Single-particle cryo-EM-Improved ab initio 3D reconstruction with SIMPLE/PRIME.

PubMed

Reboul, Cyril F; Eager, Michael; Elmlund, Dominika; Elmlund, Hans

2018-01-01

Cryogenic electron microscopy (cryo-EM) and single-particle analysis now enables the determination of high-resolution structures of macromolecular assemblies that have resisted X-ray crystallography and other approaches. We developed the SIMPLE open-source image-processing suite for analysing cryo-EM images of single-particles. A core component of SIMPLE is the probabilistic PRIME algorithm for identifying clusters of images in 2D and determine relative orientations of single-particle projections in 3D. Here, we extend our previous work on PRIME and introduce new stochastic optimization algorithms that improve the robustness of the approach. Our refined method for identification of homogeneous subsets of images in accurate register substantially improves the resolution of the cluster centers and of the ab initio 3D reconstructions derived from them. We now obtain maps with a resolution better than 10 Å by exclusively processing cluster centers. Excellent parallel code performance on over-the-counter laptops and CPU workstations is demonstrated. © 2017 The Protein Society.

Preface to Special Topic: Collective Effects in Particle Beams and Nonneutral Plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilson, Erik P.; Qin, Hong

Nonneutral plasmas are plasma systems in which there is no overall charge neutrality, including the limit of systems that are fully unneutralized in which there are particles of only a single sign of charge. Here, examples of nonneutral plasmas include charged-particle beams, pure electron plasmas, pure positron plasmas, and pure-ion plasmas consisting of a variety of ion charge states in a single trap. A key feature of nonneutral plasmas which distinguishes them from quasineutral plasmas is that their self-electric and self-magnetic fields can play a dominant role in the behavior of the system. Moreover, single-component plasmas can be confined inmore » states of global thermal equilibrium, enabling detailed theoretical and experimental studies of fundamental plasma phenomena and precise testing of models.« less

Preface to Special Topic: Collective Effects in Particle Beams and Nonneutral Plasmas

DOE PAGES

Gilson, Erik P.; Qin, Hong

2018-01-30

Nonneutral plasmas are plasma systems in which there is no overall charge neutrality, including the limit of systems that are fully unneutralized in which there are particles of only a single sign of charge. Here, examples of nonneutral plasmas include charged-particle beams, pure electron plasmas, pure positron plasmas, and pure-ion plasmas consisting of a variety of ion charge states in a single trap. A key feature of nonneutral plasmas which distinguishes them from quasineutral plasmas is that their self-electric and self-magnetic fields can play a dominant role in the behavior of the system. Moreover, single-component plasmas can be confined inmore » states of global thermal equilibrium, enabling detailed theoretical and experimental studies of fundamental plasma phenomena and precise testing of models.« less

The application of single particle aerosol mass spectrometry for the detection and identification of high explosives and chemical warfare agents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Audrey Noreen

2006-01-01

Single Particle Aerosol Mass Spectrometry (SPAMS) was evaluated as a real-time detection technique for single particles of high explosives. Dual-polarity time-of-flight mass spectra were obtained for samples of 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), and pentaerythritol tetranitrate (PETN); peaks indicative of each compound were identified. Composite explosives, Comp B, Semtex 1A, and Semtex 1H were also analyzed, and peaks due to the explosive components of each sample were present in each spectrum. Mass spectral variability with laser fluence is discussed. The ability of the SPAMS system to identify explosive components in a single complex explosive particle (~1 pg) without the need formore » consumables is demonstrated. SPAMS was also applied to the detection of Chemical Warfare Agent (CWA) simulants in the liquid and vapor phases. Liquid simulants for sarin, cyclosarin, tabun, and VX were analyzed; peaks indicative of each simulant were identified. Vapor phase CWA simulants were adsorbed onto alumina, silica, Zeolite, activated carbon, and metal powders which were directly analyzed using SPAMS. The use of metal powders as adsorbent materials was especially useful in the analysis of triethyl phosphate (TEP), a VX stimulant, which was undetectable using SPAMS in the liquid phase. The capability of SPAMS to detect high explosives and CWA simulants using one set of operational conditions is established.« less

A novel prediction method about single components of analog circuits based on complex field modeling.

PubMed

Zhou, Jingyu; Tian, Shulin; Yang, Chenglin

2014-01-01

Few researches pay attention to prediction about analog circuits. The few methods lack the correlation with circuit analysis during extracting and calculating features so that FI (fault indicator) calculation often lack rationality, thus affecting prognostic performance. To solve the above problem, this paper proposes a novel prediction method about single components of analog circuits based on complex field modeling. Aiming at the feature that faults of single components hold the largest number in analog circuits, the method starts with circuit structure, analyzes transfer function of circuits, and implements complex field modeling. Then, by an established parameter scanning model related to complex field, it analyzes the relationship between parameter variation and degeneration of single components in the model in order to obtain a more reasonable FI feature set via calculation. According to the obtained FI feature set, it establishes a novel model about degeneration trend of analog circuits' single components. At last, it uses particle filter (PF) to update parameters for the model and predicts remaining useful performance (RUP) of analog circuits' single components. Since calculation about the FI feature set is more reasonable, accuracy of prediction is improved to some extent. Finally, the foregoing conclusions are verified by experiments.

Electronic sputtering of LiF, CaF2, LaF3 and UF4 with 197 MeV Au ions. Is the stoichiometry of atom emission preserved?

NASA Astrophysics Data System (ADS)

Toulemonde, M.; Assmann, W.; Muller, D.; Trautmann, C.

2017-09-01

Sputtering experiments with swift heavy ions in the electronic energy loss regime were performed by using the catcher technique in combination with elastic recoil detection analysis. Four different fluoride targets, LiF, CaF2, LaF3 and UF4 were irradiated in the electronic energy loss regime using 197 MeV Au ions. The angular distribution of particles sputtered from the surface of freshly cleaved LiF and CaF2 single crystals is composed of a broad cosine distribution superimposed by a jet-like peak that appears perpendicular to the surface independent of the angle of beam incidence. For LiF, the particle emission in the entire angular distribution (jet plus broad cosine component) is stoichiometric, whereas for CaF2 the ratio of the sputtered F to Ca particles is at large angles by a factor of two smaller than the stoichiometry of the crystal. For single crystalline LaF3 no jet component is observed and the angular distribution is non-stoichiometric with the number of sputtered F particles being slightly larger than the number of sputtered La particles. In the case of UF4, the target was polycrystalline and had a much rougher surface compared to cleaved crystals. This destroys the appearance of a possible jet component leading to a broad angular distribution. The ratio of sputtered U atoms compared to F atoms is in the order of 1-2, i.e. the number of collected particles on the catcher is also non-stoichiometric. Such unlike behavior of particles sputtered from different fluoride crystals creates new questions.

The Umov effect in application to an optically thin two-component cloud of cosmic dust

NASA Astrophysics Data System (ADS)

Zubko, Evgenij; Videen, Gorden; Zubko, Nataliya; Shkuratov, Yuriy

2018-04-01

The Umov effect is an inverse correlation between linear polarization of the sunlight scattered by an object and its geometric albedo. The Umov effect has been observed in particulate surfaces, such as planetary regoliths, and recently it also was found in single-scattering small dust particles. Using numerical modeling, we study the Umov effect in a two-component mixture of small irregularly shaped particles. Such a complex chemical composition is suggested in cometary comae and other types of optically thin clouds of cosmic dust. We find that the two-component mixtures of small particles also reveal the Umov effect regardless of the chemical composition of their end-member components. The interrelation between log(Pmax) and log(A) in a two-component mixture of small irregularly shaped particles appears either in a straight linear form or in a slightly curved form. This curvature tends to decrease while the index n in a power-law size distribution r-n grows; at n > 2.5, the log(Pmax)-log(A) diagrams are almost straight linear in appearance. The curvature also noticeably decreases with the packing density of constituent material in irregularly shaped particles forming the mixture. That such a relation exists suggest the Umov effect may also be observed in more complex mixtures.

The Umov effect in application to an optically thin two-component cloud of cosmic dust

NASA Astrophysics Data System (ADS)

Zubko, Evgenij; Videen, Gorden; Zubko, Nataliya; Shkuratov, Yuriy

2018-07-01

The Umov effect is an inverse correlation between linear polarization of the sunlight scattered by an object and its geometric albedo. The Umov effect has been observed in particulate surfaces, such as planetary regoliths, and recently it also was found in single-scattering small dust particles. Using numerical modelling, we study the Umov effect in a two-component mixture of small irregularly shaped particles. Such a complex chemical composition is suggested in cometary comae and other types of optically thin clouds of cosmic dust. We find that the two-component mixtures of small particles also reveal the Umov effect regardless of the chemical composition of their end-member components. The interrelation between log(Pmax) and log(A) in a two-component mixture of small irregularly shaped particles appears either in a straight linear form or in a slightly curved form. This curvature tends to decrease while the index n in a power-law size distribution r-n grows; at n > 2.5, the log(Pmax)-log(A) diagrams are almost straight linear in appearance. The curvature also noticeably decreases with the packing density of constituent material in irregularly shaped particles forming the mixture. That such a relation exists suggests the Umov effect may also be observed in more complex mixtures.

Pseudorapidity dependence of long-range two-particle correlations in p Pb collisions at √{sNN}=5.02 TeV

NASA Astrophysics Data System (ADS)

Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Knünz, V.; König, A.; Krammer, M.; Krätschmer, I.; Liko, D.; Matsushita, T.; Mikulec, I.; Rabady, D.; Rad, N.; Rahbaran, B.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Knutsson, A.; Lauwers, J.; Luyckx, S.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; Daci, N.; De Bruyn, I.; Deroover, K.; Heracleous, N.; Keaveney, J.; Lowette, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Van Parijs, I.; Barria, P.; Brun, H.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Fasanella, G.; Favart, L.; Goldouzian, R.; Grebenyuk, A.; Karapostoli, G.; Lenzi, T.; Léonard, A.; Maerschalk, T.; Marinov, A.; Pernié, L.; Randle-conde, A.; Seva, T.; Vander Velde, C.; Vanlaer, P.; Yonamine, R.; Zenoni, F.; Zhang, F.; Beernaert, K.; Benucci, L.; Cimmino, A.; Crucy, S.; Dobur, D.; Fagot, A.; Garcia, G.; Gul, M.; Mccartin, J.; Ocampo Rios, A. A.; Poyraz, D.; Ryckbosch, D.; Salva, S.; Sigamani, M.; Tytgat, M.; Van Driessche, W.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bondu, O.; Brochet, S.; Bruno, G.; Caudron, A.; Ceard, L.; Delaere, C.; Favart, D.; Forthomme, L.; Giammanco, A.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Mertens, A.; Musich, M.; Nuttens, C.; Perrini, L.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Beliy, N.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, F. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Hamer, M.; Hensel, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Matos Figueiredo, D.; Mora Herrera, C.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; De Souza Santos, A.; Dogra, S.; Tomei, T. R. Fernandez Perez; Gregores, E. M.; Mercadante, P. G.; Moon, C. S.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Cheng, T.; Du, R.; Jiang, C. H.; Leggat, D.; Plestina, R.; Romeo, F.; Shaheen, S. M.; Spiezia, A.; Tao, J.; Wang, C.; Wang, Z.; Zhang, H.; Asawatangtrakuldee, C.; Ban, Y.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Puljak, I.; Ribeiro Cipriano, P. M.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Micanovic, S.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Bodlak, M.; Finger, M.; Finger, M.; Abdelalim, A. A.; Awad, A.; Mahrous, A.; Radi, A.; Calpas, B.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Pekkanen, J.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Peltola, T.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Machet, M.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Zghiche, A.; Antropov, I.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Chapon, E.; Charlot, C.; Davignon, O.; Filipovic, N.; Granier de Cassagnac, R.; Jo, M.; Lisniak, S.; Mastrolorenzo, L.; Miné, P.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Pigard, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Strebler, T.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. C.; Chanon, N.; Collard, C.; Conte, E.; Coubez, X.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Merlin, J. A.; Skovpen, K.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Bernet, C.; Boudoul, G.; Bouvier, E.; Carrillo Montoya, C. A.; Chierici, R.; Contardo, D.; Courbon, B.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Lagarde, F.; Laktineh, I. B.; Lethuillier, M.; Mirabito, L.; Pequegnot, A. L.; Perries, S.; Ruiz Alvarez, J. D.; Sabes, D.; Sgandurra, L.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Toriashvili, T.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.; Feld, L.; Heister, A.; Kiesel, M. K.; Klein, K.; Lipinski, M.; Ostapchuk, A.; Preuten, M.; Raupach, F.; Schael, S.; Schulte, J. F.; Verlage, T.; Weber, H.; Zhukov, V.; Ata, M.; Brodski, M.; Dietz-Laursonn, E.; Duchardt, D.; Endres, M.; Erdmann, M.; Erdweg, S.; Esch, T.; Fischer, R.; Güth, A.; Hebbeker, T.; Heidemann, C.; Hoepfner, K.; Knutzen, S.; Kreuzer, P.; Merschmeyer, M.; Meyer, A.; Millet, P.; Mukherjee, S.; Olschewski, M.; Padeken, K.; Papacz, P.; Pook, T.; Radziej, M.; Reithler, H.; Rieger, M.; Scheuch, F.; Sonnenschein, L.; Teyssier, D.; Thüer, S.; Cherepanov, V.; Erdogan, Y.; Flügge, G.; Geenen, H.; Geisler, M.; Hoehle, F.; Kargoll, B.; Kress, T.; Künsken, A.; Lingemann, J.; Nehrkorn, A.; Nowack, A.; Nugent, I. M.; Pistone, C.; Pooth, O.; Stahl, A.; Aldaya Martin, M.; Asin, I.; Bartosik, N.; Behnke, O.; Behrens, U.; Borras, K.; Burgmeier, A.; Campbell, A.; Contreras-Campana, C.; Costanza, F.; Diez Pardos, C.; Dolinska, G.; Dooling, S.; Dorland, T.; Eckerlin, G.; Eckstein, D.; Eichhorn, T.; Flucke, G.; Gallo, E.; Garay Garcia, J.; Geiser, A.; Gizhko, A.; Gunnellini, P.; Hauk, J.; Hempel, M.; Jung, H.; Kalogeropoulos, A.; Karacheban, O.; Kasemann, M.; Katsas, P.; Kieseler, J.; Kleinwort, C.; Korol, I.; Lange, W.; Leonard, J.; Lipka, K.; Lobanov, A.; Lohmann, W.; Mankel, R.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Naumann-Emme, S.; Nayak, A.; Ntomari, E.; Perrey, H.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Roland, B.; Sahin, M. Ö.; Saxena, P.; Schoerner-Sadenius, T.; Seitz, C.; Spannagel, S.; Trippkewitz, K. D.; Walsh, R.; Wissing, C.; Blobel, V.; Centis Vignali, M.; Draeger, A. R.; Erfle, J.; Garutti, E.; Goebel, K.; Gonzalez, D.; Görner, M.; Haller, J.; Hoffmann, M.; Höing, R. S.; Junkes, A.; Klanner, R.; Kogler, R.; Kovalchuk, N.; Lapsien, T.; Lenz, T.; Marchesini, I.; Marconi, D.; Meyer, M.; Nowatschin, D.; Ott, J.; Pantaleo, F.; Peiffer, T.; Perieanu, A.; Pietsch, N.; Poehlsen, J.; Rathjens, D.; Sander, C.; Scharf, C.; Schleper, P.; Schlieckau, E.; Schmidt, A.; Schumann, S.; Schwandt, J.; Sola, V.; Stadie, H.; Steinbrück, G.; Stober, F. M.; Tholen, H.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Vormwald, B.; Barth, C.; Baus, C.; Berger, J.; Böser, C.; Butz, E.; Chwalek, T.; Colombo, F.; De Boer, W.; Descroix, A.; Dierlamm, A.; Fink, S.; Frensch, F.; Friese, R.; Giffels, M.; Gilbert, A.; Haitz, D.; Hartmann, F.; Heindl, S. M.; Husemann, U.; Katkov, I.; Kornmayer, A.; Lobelle Pardo, P.; Maier, B.; Mildner, H.; Mozer, M. U.; Müller, T.; Müller, Th.; Plagge, M.; Quast, G.; Rabbertz, K.; Röcker, S.; Roscher, F.; Schröder, M.; Sieber, G.; Simonis, H. J.; Ulrich, R.; Wagner-Kuhr, J.; Wayand, S.; Weber, M.; Weiler, T.; Williamson, S.; Wöhrmann, C.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Psallidas, A.; Topsis-Giotis, I.; Agapitos, A.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Tziaferi, E.; Evangelou, I.; Flouris, G.; Foudas, C.; Kokkas, P.; Loukas, N.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Strologas, J.; Bencze, G.; Hajdu, C.; Hazi, A.; Hidas, P.; Horvath, D.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Molnar, J.; Szillasi, Z.; Bartók, M.; Makovec, A.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Choudhury, S.; Mal, P.; Mandal, K.; Sahoo, D. K.; Sahoo, N.; Swain, S. K.; Bansal, S.; Beri, S. B.; Bhatnagar, V.; Chawla, R.; Gupta, R.; Bhawandeep, U.; Kalsi, A. K.; Kaur, A.; Kaur, M.; Kumar, R.; Mehta, A.; Mittal, M.; Singh, J. B.; Walia, G.; Kumar, Ashok; Bhardwaj, A.; Choudhary, B. C.; Garg, R. B.; Malhotra, S.; Naimuddin, M.; Nishu, N.; Ranjan, K.; Sharma, R.; Sharma, V.; Bhattacharya, S.; Chatterjee, K.; Dey, S.; Dutta, S.; Majumdar, N.; Modak, A.; Mondal, K.; Mukhopadhyay, S.; Roy, A.; Roy, D.; Roy Chowdhury, S.; Sarkar, S.; Sharan, M.; Abdulsalam, A.; Chudasama, R.; Dutta, D.; Jha, V.; Kumar, V.; Mohanty, A. K.; Pant, L. M.; Shukla, P.; Topkar, A.; Aziz, T.; Banerjee, S.; Bhowmik, S.; Chatterjee, R. M.; Dewanjee, R. K.; Dugad, S.; Ganguly, S.; Ghosh, S.; Guchait, M.; Gurtu, A.; Jain, Sa.; Kole, G.; Kumar, S.; Mahakud, B.; Maity, M.; Majumder, G.; Mazumdar, K.; Mitra, S.; Mohanty, G. B.; Parida, B.; Sarkar, T.; Sur, N.; Sutar, B.; Wickramage, N.; Chauhan, S.; Dube, S.; Kapoor, A.; Kothekar, K.; Sharma, S.; Bakhshiansohi, H.; Behnamian, H.; Etesami, S. M.; Fahim, A.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Calabria, C.; Caputo, C.; Colaleo, A.; Creanza, D.; Cristella, L.; De Filippis, N.; De Palma, M.; Fiore, L.; Iaselli, G.; Maggi, G.; Maggi, M.; Miniello, G.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Ranieri, A.; Selvaggi, G.; Silvestris, L.; Venditti, R.; Abbiendi, G.; Battilana, C.; Benvenuti, A. C.; Bonacorsi, D.; Braibant-Giacomelli, S.; Brigliadori, L.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Chhibra, S. S.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Grandi, C.; Guiducci, L.; Marcellini, S.; Masetti, G.; Montanari, A.; Navarria, F. L.; Perrotta, A.; Rossi, A. M.; Rovelli, T.; Siroli, G. P.; Tosi, N.; Cappello, G.; Chiorboli, M.; Costa, S.; Di Mattia, A.; Giordano, F.; Potenza, R.; Tricomi, A.; Tuve, C.; Barbagli, G.; Ciulli, V.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Gori, V.; Lenzi, P.; Meschini, M.; Paoletti, S.; Sguazzoni, G.; Viliani, L.; Benussi, L.; Bianco, S.; Fabbri, F.; Piccolo, D.; Primavera, F.; Calvelli, V.; Ferro, F.; Lo Vetere, M.; Monge, M. R.; Robutti, E.; Tosi, S.; Brianza, L.; Dinardo, M. E.; Fiorendi, S.; Gennai, S.; Gerosa, R.; Ghezzi, A.; Govoni, P.; Malvezzi, S.; Manzoni, R. A.; Marzocchi, B.; Menasce, D.; Moroni, L.; Paganoni, M.; Pedrini, D.; Ragazzi, S.; Redaelli, N.; Tabarelli de Fatis, T.; Buontempo, S.; Cavallo, N.; Di Guida, S.; Esposito, M.; Fabozzi, F.; Iorio, A. O. M.; Lanza, G.; Lista, L.; Meola, S.; Merola, M.; Paolucci, P.; Sciacca, C.; Thyssen, F.; Azzi, P.; Bacchetta, N.; Bellato, M.; Benato, L.; Boletti, A.; Branca, A.; Dall'Osso, M.; Dorigo, T.; Fantinel, S.; Fanzago, F.; Gonella, F.; Gozzelino, A.; Kanishchev, K.; Lacaprara, S.; Margoni, M.; Meneguzzo, A. T.; Montecassiano, F.; Passaseo, M.; Pazzini, J.; Pegoraro, M.; Pozzobon, N.; Ronchese, P.; Simonetto, F.; Torassa, E.; Tosi, M.; Ventura, S.; Zanetti, M.; Zotto, P.; Zucchetta, A.; Braghieri, A.; Magnani, A.; Montagna, P.; Ratti, S. P.; Re, V.; Riccardi, C.; Salvini, P.; Vai, I.; Vitulo, P.; Alunni Solestizi, L.; Bilei, G. M.; Ciangottini, D.; Fanò, L.; Lariccia, P.; Mantovani, G.; Menichelli, M.; Saha, A.; Santocchia, A.; Androsov, K.; Azzurri, P.; Bagliesi, G.; Bernardini, J.; Boccali, T.; Castaldi, R.; Ciocci, M. A.; Dell'Orso, R.; Donato, S.; Fedi, G.; Foà, L.; Giassi, A.; Grippo, M. T.; Ligabue, F.; Lomtadze, T.; Martini, L.; Messineo, A.; Palla, F.; Rizzi, A.; Savoy-Navarro, A.; Serban, A. T.; Spagnolo, P.; Tenchini, R.; Tonelli, G.; Venturi, A.; Verdini, P. G.; Barone, L.; Cavallari, F.; D'imperio, G.; Del Re, D.; Diemoz, M.; Gelli, S.; Jorda, C.; Longo, E.; Margaroli, F.; Meridiani, P.; Organtini, G.; Paramatti, R.; Preiato, F.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Traczyk, P.; Amapane, N.; Arcidiacono, R.; Argiro, S.; Arneodo, M.; Bellan, R.; Biino, C.; Cartiglia, N.; Costa, M.; Covarelli, R.; Degano, A.; Demaria, N.; Finco, L.; Kiani, B.; Mariotti, C.; Maselli, S.; Migliore, E.; Monaco, V.; Monteil, E.; Obertino, M. M.; Pacher, L.; Pastrone, N.; Pelliccioni, M.; Pinna Angioni, G. L.; Ravera, F.; Romero, A.; Ruspa, M.; Sacchi, R.; Solano, A.; Staiano, A.; Belforte, S.; Candelise, V.; Casarsa, M.; Cossutti, F.; Della Ricca, G.; Gobbo, B.; La Licata, C.; Marone, M.; Schizzi, A.; Zanetti, A.; Kropivnitskaya, A.; Nam, S. K.; Kim, D. H.; Kim, G. N.; Kim, M. S.; Kong, D. J.; Lee, S.; Oh, Y. D.; Sakharov, A.; Son, D. C.; Brochero Cifuentes, J. A.; Kim, H.; Kim, T. J.; Song, S.; Cho, S.; Choi, S.; Go, Y.; Gyun, D.; Hong, B.; Kim, H.; Kim, Y.; Lee, B.; Lee, K.; Lee, K. S.; Lee, S.; Park, S. K.; Roh, Y.; Yoo, H. D.; Choi, M.; Kim, H.; Kim, J. H.; Lee, J. S. H.; Park, I. C.; Ryu, G.; Ryu, M. S.; Choi, Y.; Goh, J.; Kim, D.; Kwon, E.; Lee, J.; Yu, I.; Dudenas, V.; Juodagalvis, A.; Vaitkus, J.; Ahmed, I.; Ibrahim, Z. A.; Komaragiri, J. R.; Md Ali, M. A. B.; Mohamad Idris, F.; Wan Abdullah, W. A. T.; Yusli, M. N.; Zolkapli, Z.; Casimiro Linares, E.; Castilla-Valdez, H.; De La Cruz-Burelo, E.; Heredia-De La Cruz, I.; Hernandez-Almada, A.; Lopez-Fernandez, R.; Sanchez-Hernandez, A.; Carrillo Moreno, S.; Vazquez Valencia, F.; Pedraza, I.; Salazar Ibarguen, H. A.; Morelos Pineda, A.; Krofcheck, D.; Butler, P. H.; Ahmad, A.; Ahmad, M.; Hassan, Q.; Hoorani, H. R.; Khan, W. 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V.; Baskakov, A.; Belyaev, A.; Boos, E.; Ershov, A.; Gribushin, A.; Kaminskiy, A.; Kodolova, O.; Korotkikh, V.; Lokhtin, I.; Miagkov, I.; Obraztsov, S.; Petrushanko, S.; Savrin, V.; Snigirev, A.; Vardanyan, I.; Azhgirey, I.; Bayshev, I.; Bitioukov, S.; Kachanov, V.; Kalinin, A.; Konstantinov, D.; Krychkine, V.; Petrov, V.; Ryutin, R.; Sobol, A.; Tourtchanovitch, L.; Troshin, S.; Tyurin, N.; Uzunian, A.; Volkov, A.; Adzic, P.; Cirkovic, P.; Milosevic, J.; Rekovic, V.; Alcaraz Maestre, J.; Calvo, E.; Cerrada, M.; Chamizo Llatas, M.; Colino, N.; De La Cruz, B.; Delgado Peris, A.; Escalante Del Valle, A.; Fernandez Bedoya, C.; Fernández Ramos, J. P.; Flix, J.; Fouz, M. C.; Garcia-Abia, P.; Gonzalez Lopez, O.; Goy Lopez, S.; Hernandez, J. M.; Josa, M. I.; Navarro De Martino, E.; Pérez-Calero Yzquierdo, A.; Puerta Pelayo, J.; Quintario Olmeda, A.; Redondo, I.; Romero, L.; Santaolalla, J.; Soares, M. S.; Albajar, C.; de Trocóniz, J. 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V.; Neugebauer, H.; Orfanelli, S.; Orsini, L.; Pape, L.; Perez, E.; Peruzzi, M.; Petrilli, A.; Petrucciani, G.; Pfeiffer, A.; Pierini, M.; Piparo, D.; Racz, A.; Reis, T.; Rolandi, G.; Rovere, M.; Ruan, M.; Sakulin, H.; Schäfer, C.; Schwick, C.; Seidel, M.; Sharma, A.; Silva, P.; Simon, M.; Sphicas, P.; Steggemann, J.; Stieger, B.; Stoye, M.; Takahashi, Y.; Treille, D.; Triossi, A.; Tsirou, A.; Veres, G. I.; Wardle, N.; Wöhri, H. K.; Zagozdzinska, A.; Zeuner, W. D.; Bertl, W.; Deiters, K.; Erdmann, W.; Horisberger, R.; Ingram, Q.; Kaestli, H. C.; Kotlinski, D.; Langenegger, U.; Rohe, T.; Bachmair, F.; Bäni, L.; Bianchini, L.; Casal, B.; Dissertori, G.; Dittmar, M.; Donegá, M.; Eller, P.; Grab, C.; Heidegger, C.; Hits, D.; Hoss, J.; Kasieczka, G.; Lecomte, P.; Lustermann, W.; Mangano, B.; Marionneau, M.; Martinez Ruiz del Arbol, P.; Masciovecchio, M.; Meister, D.; Micheli, F.; Musella, P.; Nessi-Tedaldi, F.; Pandolfi, F.; Pata, J.; Pauss, F.; Perrozzi, L.; Quittnat, M.; Rossini, M.; Schönenberger, M.; Starodumov, A.; Takahashi, M.; Tavolaro, V. R.; Theofilatos, K.; Wallny, R.; Aarrestad, T. K.; Amsler, C.; Caminada, L.; Canelli, M. F.; Chiochia, V.; De Cosa, A.; Galloni, C.; Hinzmann, A.; Hreus, T.; Kilminster, B.; Lange, C.; Ngadiuba, J.; Pinna, D.; Rauco, G.; Robmann, P.; Salerno, D.; Yang, Y.; Cardaci, M.; Chen, K. H.; Doan, T. H.; Jain, Sh.; Khurana, R.; Konyushikhin, M.; Kuo, C. M.; Lin, W.; Lu, Y. J.; Pozdnyakov, A.; Yu, S. S.; Kumar, Arun; Chang, P.; Chang, Y. H.; Chang, Y. W.; Chao, Y.; Chen, K. F.; Chen, P. 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C.; Apyan, A.; Barbieri, R.; Baty, A.; Bierwagen, K.; Brandt, S.; Busza, W.; Cali, I. A.; Demiragli, Z.; Di Matteo, L.; Gomez Ceballos, G.; Goncharov, M.; Gulhan, D.; Iiyama, Y.; Innocenti, G. M.; Klute, M.; Kovalskyi, D.; Lai, Y. S.; Lee, Y.-J.; Levin, A.; Luckey, P. D.; Marini, A. C.; Mcginn, C.; Mironov, C.; Narayanan, S.; Niu, X.; Paus, C.; Roland, C.; Roland, G.; Salfeld-Nebgen, J.; Stephans, G. S. F.; Sumorok, K.; Varma, M.; Velicanu, D.; Veverka, J.; Wang, J.; Wang, T. W.; Wyslouch, B.; Yang, M.; Zhukova, V.; Dahmes, B.; Evans, A.; Finkel, A.; Gude, A.; Hansen, P.; Kalafut, S.; Kao, S. C.; Klapoetke, K.; Kubota, Y.; Lesko, Z.; Mans, J.; Nourbakhsh, S.; Ruckstuhl, N.; Rusack, R.; Tambe, N.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bartek, R.; Bloom, K.; Bose, S.; Claes, D. R.; Dominguez, A.; Fangmeier, C.; Gonzalez Suarez, R.; Kamalieddin, R.; Knowlton, D.; Kravchenko, I.; Meier, F.; Monroy, J.; Ratnikov, F.; Siado, J. E.; Snow, G. R.; Alyari, M.; Dolen, J.; George, J.; Godshalk, A.; Harrington, C.; Iashvili, I.; Kaisen, J.; Kharchilava, A.; Kumar, A.; Rappoccio, S.; Roozbahani, B.; Alverson, G.; Barberis, E.; Baumgartel, D.; Chasco, M.; Hortiangtham, A.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Teixeira De Lima, R.; Trocino, D.; Wang, R.-J.; Wood, D.; Zhang, J.; Bhattacharya, S.; Hahn, K. A.; Kubik, A.; Low, J. F.; Mucia, N.; Odell, N.; Pollack, B.; Schmitt, M.; Sung, K.; Trovato, M.; Velasco, M.; Brinkerhoff, A.; Dev, N.; Hildreth, M.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Marinelli, N.; Meng, F.; Mueller, C.; Musienko, Y.; Planer, M.; Reinsvold, A.; Ruchti, R.; Smith, G.; Taroni, S.; Valls, N.; Wayne, M.; Wolf, M.; Woodard, A.; Antonelli, L.; Brinson, J.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Hart, A.; Hill, C.; Hughes, R.; Ji, W.; Ling, T. Y.; Liu, B.; Luo, W.; Puigh, D.; Rodenburg, M.; Winer, B. L.; Wulsin, H. W.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Koay, S. A.; Lujan, P.; Marlow, D.; Medvedeva, T.; Mooney, M.; Olsen, J.; Palmer, C.; Piroué, P.; Stickland, D.; Tully, C.; Zuranski, A.; Malik, S.; Barker, A.; Barnes, V. E.; Benedetti, D.; Bortoletto, D.; Gutay, L.; Jha, M. K.; Jones, M.; Jung, A. W.; Jung, K.; Kumar, A.; Miller, D. H.; Neumeister, N.; Radburn-Smith, B. C.; Shi, X.; Shipsey, I.; Silvers, D.; Sun, J.; Svyatkovskiy, A.; Wang, F.; Xie, W.; Xu, L.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Chen, Z.; Ecklund, K. M.; Geurts, F. J. M.; Guilbaud, M.; Li, W.; Michlin, B.; Northup, M.; Padley, B. P.; Redjimi, R.; Roberts, J.; Rorie, J.; Tu, Z.; Zabel, J.; Betchart, B.; Bodek, A.; de Barbaro, P.; Demina, R.; Eshaq, Y.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Han, J.; Harel, A.; Hindrichs, O.; Khukhunaishvili, A.; Lo, K. H.; Petrillo, G.; Tan, P.; Verzetti, M.; Chou, J. P.; Contreras-Campana, E.; Ferencek, D.; Gershtein, Y.; Halkiadakis, E.; Heindl, M.; Hidas, D.; Hughes, E.; Kaplan, S.; Kunnawalkam Elayavalli, R.; Lath, A.; Nash, K.; Saka, H.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Foerster, M.; Riley, G.; Rose, K.; Spanier, S.; Thapa, K.; Bouhali, O.; Castaneda Hernandez, A.; Celik, A.; Dalchenko, M.; De Mattia, M.; Delgado, A.; Dildick, S.; Eusebi, R.; Gilmore, J.; Huang, T.; Kamon, T.; Krutelyov, V.; Mueller, R.; Osipenkov, I.; Pakhotin, Y.; Patel, R.; Perloff, A.; Rose, A.; Safonov, A.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Cowden, C.; Damgov, J.; Dragoiu, C.; Dudero, P. R.; Faulkner, J.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Undleeb, S.; Volobouev, I.; Appelt, E.; Delannoy, A. G.; Greene, S.; Gurrola, A.; Janjam, R.; Johns, W.; Maguire, C.; Mao, Y.; Melo, A.; Ni, H.; Sheldon, P.; Tuo, S.; Velkovska, J.; Xu, Q.; Arenton, M. W.; Cox, B.; Francis, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Li, H.; Lin, C.; Neu, C.; Sinthuprasith, T.; Sun, X.; Wang, Y.; Wolfe, E.; Wood, J.; Xia, F.; Clarke, C.; Harr, R.; Karchin, P. E.; Kottachchi Kankanamge Don, C.; Lamichhane, P.; Sturdy, J.; Belknap, D. A.; Carlsmith, D.; Cepeda, M.; Dasu, S.; Dodd, L.; Duric, S.; Gomber, B.; Grothe, M.; Herndon, M.; Hervé, A.; Klabbers, P.; Lanaro, A.; Levine, A.; Long, K.; Loveless, R.; Mohapatra, A.; Ojalvo, I.; Perry, T.; Pierro, G. A.; Polese, G.; Ruggles, T.; Sarangi, T.; Savin, A.; Sharma, A.; Smith, N.; Smith, W. H.; Taylor, D.; Verwilligen, P.; Woods, N.; CMS Collaboration

2017-07-01

Two-particle correlations in p Pb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV are studied as a function of the pseudorapidity separation (Δ η ) of the particle pair at small relative azimuthal angle (|Δ ϕ |<π /3 ). The correlations are decomposed into a jet component that dominates the short-range correlations (|Δ η |<1 ), and a component that persists at large Δ η and may originate from collective behavior of the produced system. The events are classified in terms of the multiplicity of the produced particles. Finite azimuthal anisotropies are observed in high-multiplicity events. The second and third Fourier components of the particle-pair azimuthal correlations, V2 and V3, are extracted after subtraction of the jet component. The single-particle anisotropy parameters v2 and v3 are normalized by their laboratory frame midrapidity value and are studied as a function of ηc.m.. The normalized v2 distribution is found to be asymmetric about ηc.m.=0 , with smaller values observed at forward pseudorapidity, corresponding to the direction of the proton beam, while no significant pseudorapidity dependence is observed for the normalized v3 distribution within the statistical uncertainties.

Pseudorapidity dependence of long-range two-particle correlations in $p$Pb collisions at $$\\sqrt{s_{NN}}=5.02$$ TeV

DOE PAGES

Khachatryan, Vardan

2016-04-18

Two-particle correlations in pPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV are studied as a function of the pseudorapidity separation (Delta eta) of the particle pair at small relative azimuthal angle (abs(Delta phi)< pi/3). The correlations are decomposed into a jet component that dominates the short-range correlations (abs(Delta eta) < 1), and a component that persists at large Delta eta and may originate from collective behavior of the produced system. The events are classified in terms of the multiplicity of the produced particles. Finite azimuthal anisotropies are observed in high-multiplicity events. The second and third Fourier components ofmore » the particle-pair azimuthal correlations, V[2] and V[3], are extracted after subtraction of the jet component. The single-particle anisotropy parameters v[2] and v[3] are normalized by their lab frame mid-rapidity value and are studied as a function of eta[cm]. The normalized v[2] distribution is found to be asymmetric about eta[cm] = 0, with smaller values observed at forward pseudorapidity, corresponding to the direction of the proton beam, while no significant pseudorapidity dependence is observed for the normalized v[3] distribution within the statistical uncertainties.« less

Formation of a new archetypal Metal-Organic Framework from a simple monatomic liquid

NASA Astrophysics Data System (ADS)

Metere, Alfredo; Oleynikov, Peter; Dzugutov, Mikhail; O'Keeffe, Michael

2014-12-01

We report a molecular-dynamics simulation of a single-component system of particles interacting via a spherically symmetric potential that is found to form, upon cooling from a liquid state, a low-density porous crystalline phase. Its structure analysis demonstrates that the crystal can be described by a net with a topology that belongs to the class of topologies characteristic of the Metal-Organic Frameworks (MOFs). The observed net is new, and it is now included in the Reticular Chemistry Structure Resource database. The observation that a net topology characteristic of MOF crystals, which are known to be formed by a coordination-driven self-assembly process, can be reproduced by a thermodynamically stable configuration of a simple single-component system of particles opens a possibility of using these models in studies of MOF nets. It also indicates that structures with MOF topology, as well as other low-density porous crystalline structures can possibly be produced in colloidal systems of spherical particles, with an appropriate tuning of interparticle interaction.

Wounded Nucleon Model and Deuteron--Gold Collisions at RHIC

NASA Astrophysics Data System (ADS)

Bialas, A.; Czyz, W.

2005-03-01

It is shown that the wounded nucleon model describes very well the recent PHOBOS data on particle production in D--Au collisions at 200 GeV. Contribution to particle production from a single wounded nucleon is determined. A two-component model is formulated and shown to account for most of the important features of the data.

North Massif lithologies and chemical compositions viewed from 2-4 mm particles of soil sample 76503

NASA Technical Reports Server (NTRS)

Bishop, Kaylynn M.; Jolliff, Bradley L.; Korotev, Randy L.; Haskin, Larry A.

1992-01-01

We identify the lithologic and compositional components of soil 76503 based on INAA of 243 2-4-mm particles and 72 thin sections from these and associated 1-2-mm particles (76502). We present a statistical distribution of the major compositional types as the first step of a detailed comparative study of the North and South Massifs. The soil sample was collected well away from any boulder and is more representative of typical North Massif material than any single large rock or boulder sample. So far, our examination of the 76503 particles has provided a better definition of precursor igneous lithologies and their petrogenetic relationships. It has enabled us to refine the nature of mixing components for the North Massif less than 1-mm fines. It has confirmed the differences in lithologies and their proportions between materials of the North and South Massifs; e.g., the North Massif is distinguished by the absence of a 72275-type KREEP component, the abundance of a highly magnesian igneous component, and the absence of certain types of melt compositions found in the South Massif samples.

Low-background EN-detector for the investigation of the neutron component of EASs

NASA Astrophysics Data System (ADS)

Gromushkin, D. M.; Bogdanov, F. A.; Lakhonin, A. A.; Petrukhin, A. A.; Stenkin, Yu. V.; Shchegolev, O. B.; Yurin, K. O.; Yashin, I. I.

2018-01-01

Thermal neutrons are detected using a scintillator compound based on ZnS(Ag) with B2O3 added to it. The pulse height generated by single charged particles in a scintillator of small thickness (50 mg/cm2) is not larger than that of a noise signal due to a low sensitivity to single charged particles. As a result, the detector satisfies the requirements of a low-background one in the context of cosmic-ray experiments. The detector is to be used for neutron detection in extensive air showers.

Dissolution of solid dosage form. II. Equations for the dissolution of nondisintegrating tablet under the sink condition.

PubMed

Yonezawa, Y; Shirakura, K; Otsuka, A; Sunada, H

1991-03-01

An equation for dissolution from the whole surface of a nondisintegrating single component tablet under the sink condition was derived. Also, equations for several dissolution manners of the tablet under the sink condition were derived in the postulation of the dominant dissolution rate constant which determines the dissolution manner. The applicability or validity of these equations were examined by the dissolution measurements with nondisintegrating single component tablets. About one-tenth the amount of the amount needed to saturate the solution was used to prepare a tablet, and dissolution measurements were carried out with the tablet whose flat or side surface was masked with an adhesive tape in accordance with the conditions for derivation of equations. Among the derived equations, dissolution from the whole surface of a tablet was expressed by a form similar to the cube root law equation for particles. Hence, a single component tablet compressed by the use of a suitable amount was thought to behave like a single crystal. Also, equations derived for several dissolution manners were thought to be applicable for the dissolution of a nonspherical particle and crystal concerning the crystal's habit and its dissolution property, and the extended applicability was examined by converting the crystal into a simplified or idealized form, i.e., rectangle or plate.

Stability of binary and ternary model oil-field particle suspensions: a multivariate analysis approach.

PubMed

Dudásová, Dorota; Rune Flåten, Geir; Sjöblom, Johan; Øye, Gisle

2009-09-15

The transmission profiles of one- to three-component particle suspension mixtures were analyzed by multivariate methods such as principal component analysis (PCA) and partial least-squares regression (PLS). The particles mimic the solids present in oil-field-produced water. Kaolin and silica represent solids of reservoir origin, whereas FeS is the product of bacterial metabolic activities, and Fe(3)O(4) corrosion product (e.g., from pipelines). All particles were coated with crude oil surface active components to imitate particles in real systems. The effects of different variables (concentration, temperature, and coating) on the suspension stability were studied with Turbiscan LAb(Expert). The transmission profiles over 75 min represent the overall water quality, while the transmission during the first 15.5 min gives information for suspension behavior during a representative time period for the hold time in the separator. The behavior of the mixed particle suspensions was compared to that of the single particle suspensions and models describing the systems were built. The findings are summarized as follows: silica seems to dominate the mixture properties in the binary suspensions toward enhanced separation. For 75 min, temperature and concentration are the most significant, while for 15.5 min, concentration is the only significant variable. Models for prediction of transmission spectra from run parameters as well as particle type from transmission profiles (inverse calibration) give a reasonable description of the relationships. In ternary particle mixtures, silica is not dominant and for 75 min, the significant variables for mixture (temperature and coating) are more similar to single kaolin and FeS/Fe(3)O(4). On the other hand, for 15.5 min, the coating is the most significant and this is similar to one for silica (at 15.5 min). The model for prediction of transmission spectra from run parameters gives good estimates of the transmission profiles. Although the model for prediction of particle type from transmission parameters is able to predict some particles, further improvement is required before all particles are consistently correctly classified. Cross-validation was done for both models and estimation errors are reported.

Optical properties of mineral dust aerosol including analysis of particle size, composition, and shape effects, and the impact of physical and chemical processing

NASA Astrophysics Data System (ADS)

Alexander, Jennifer Mary

Atmospheric mineral dust has a large impact on the earth's radiation balance and climate. The radiative effects of mineral dust depend on factors including, particle size, shape, and composition which can all be extremely complex. Mineral dust particles are typically irregular in shape and can include sharp edges, voids, and fine scale surface roughness. Particle shape can also depend on the type of mineral and can vary as a function of particle size. In addition, atmospheric mineral dust is a complex mixture of different minerals as well as other, possibly organic, components that have been mixed in while these particles are suspended in the atmosphere. Aerosol optical properties are investigated in this work, including studies of the effect of particle size, shape, and composition on the infrared (IR) extinction and visible scattering properties in order to achieve more accurate modeling methods. Studies of particle shape effects on dust optical properties for single component mineral samples of silicate clay and diatomaceous earth are carried out here first. Experimental measurements are modeled using T-matrix theory in a uniform spheroid approximation. Previous efforts to simulate the measured optical properties of silicate clay, using models that assumed particle shape was independent of particle size, have achieved only limited success. However, a model which accounts for a correlation between particle size and shape for the silicate clays offers a large improvement over earlier modeling approaches. Diatomaceous earth is also studied as an example of a single component mineral dust aerosol with extreme particle shapes. A particle shape distribution, determined by fitting the experimental IR extinction data, used as a basis for modeling the visible light scattering properties. While the visible simulations show only modestly good agreement with the scattering data, the fits are generally better than those obtained using more commonly invoked particle shape distributions. The next goal of this work is to investigate if modeling methods developed in the studies of single mineral components can be generalized to predict the optical properties of more authentic aerosol samples which are complex mixtures of different minerals. Samples of Saharan sand, Iowa loess, and Arizona road dust are used here as test cases. T-matrix based simulations of the authentic samples, using measured particle size distributions, empirical mineralogies, and a priori particle shape models for each mineral component are directly compared with the measured IR extinction spectra and visible scattering profiles. This modeling approach offers a significant improvement over more commonly applied models that ignore variations in particle shape with size or mineralogy and include only a moderate range of shape parameters. Mineral dust samples processed with organic acids and humic material are also studied in order to explore how the optical properties of dust can change after being aged in the atmosphere. Processed samples include quartz mixed with humic material, and calcite reacted with acetic and oxalic acid. Clear differences in the light scattering properties are observed for all three processed mineral dust samples when compared to the unprocessed mineral dust or organic salt products. These interactions result in both internal and external mixtures depending on the sample. In addition, the presence of these organic materials can alter the mineral dust particle shape. Overall, however, these results demonstrate the need to account for the effects of atmospheric aging of mineral dust on aerosol optical properties. Particle shape can also affect the aerodynamic properties of mineral dust aerosol. In order to account for these effects, the dynamic shape factor is used to give a measure of particle asphericity. Dynamic shape factors of quartz are measured by mass and mobility selecting particles and measuring their vacuum aerodynamic diameter. From this, dynamic shape factors in both the transition and vacuum regime can be derived. The measured dynamic shape factors of quartz agree quite well with the spheroidal shape distributions derived through studies of the optical properties.

Temperature effects on drift of suspended single-domain particles induced by the Magnus force

NASA Astrophysics Data System (ADS)

Denisov, S. I.; Lyutyy, T. V.; Reva, V. V.; Yermolenko, A. S.

2018-03-01

We study the temperature dependence of the drift velocity of single-domain ferromagnetic particles induced by the Magnus force in a dilute suspension. A set of stochastic equations describing the translational and rotational dynamics of particles is derived, and the particle drift velocity that depends on components of the average particle magnetization is introduced. The Fokker-Planck equation for the probability density of magnetization orientations is solved analytically in the limit of strong thermal fluctuations for both the planar rotor and general models. Using these solutions, we calculate the drift velocity and show that the out-of-plane fluctuations of magnetization, which are not accounted for in the planar rotor model, play an important role. In the general case of arbitrary fluctuations, we investigate the temperature dependence of the drift velocity by numerically simulating a set of effective stochastic differential equations for the magnetization dynamics.

The luminescence characteristics of CsI(Na) crystal under α and X/γ excitation

NASA Astrophysics Data System (ADS)

Liu, Jinliang; Liu, Fang; Ouyang, Xiaoping; Liu, Bin; Chen, Liang; Ruan, Jinlu; Zhang, Zhongbing; Liu, Jun

2013-01-01

In this paper, we study the effective decay time characteristic of CsI(Na) crystal under 239Pu alpha particle and 137Cs gamma-ray excitation using a single photon counting decay time measurement system. The measurement system employs a silicon optical fiber to couple and transit single photon. The slow decay time component of CsI(Na) crystal is 460-550 ns. We observe a 15 ns fast decay component under alpha particle excitation. In addition, we find that the primary stage of the falling edge in the decay time curve is non-exponential and drops rapidly when CsI(Na) crystal is excited by 239Pu alpha particles. Since the high density of self-trapped-excitons (STEs) is produced in alpha particle excitation process, we propose that the fast falling edge is corresponding to the quenching process of STEs which transit with non-radiation in the case of high excitation density. To prove this proposal, we excited the CsI(Na) crystal with sub-nanosecond intensive pulsed X-ray radiation. Our X-ray impinging results show that the fast falling edge also exists under low energy (average 100 keV) bremsstrahlung X-ray excitation.

Single particle characterization using a light scattering module coupled to a time-of-flight aerosol mass spectrometer

NASA Astrophysics Data System (ADS)

Cross, E. S.; Onasch, T. B.; Canagaratna, M.; Jayne, J. T.; Kimmel, J.; Yu, X.-Y.; Alexander, M. L.; Worsnop, D. R.; Davidovits, P.

2008-12-01

We present the first single particle results obtained using an Aerodyne time-of-flight aerosol mass spectrometer coupled with a light scattering module (LS-ToF-AMS). The instrument was deployed at the T1 ground site approximately 40 km northeast of the Mexico City Metropolitan Area (MCMA) as part of the MILAGRO field study in March of 2006. The instrument was operated as a standard AMS from 12-30 March, acquiring average chemical composition and size distributions for the ambient aerosol, and in single particle mode from 27-30 March. Over a 75-h sampling period, 12 853 single particle mass spectra were optically triggered, saved, and analyzed. The correlated optical and chemical detection allowed detailed examination of single particle collection and quantification within the LS-ToF-AMS. The single particle data enabled the mixing states of the ambient aerosol to be characterized within the context of the size-resolved ensemble chemical information. The particulate mixing states were examined as a function of sampling time and most of the particles were found to be internal mixtures containing many of the organic and inorganic species identified in the ensemble analysis. The single particle mass spectra were deconvolved, using techniques developed for ensemble AMS data analysis, into HOA, OOA, NH4NO3, (NH4)2SO4, and NH4Cl fractions. Average single particle mass and chemistry measurements are shown to be in agreement with ensemble MS and PTOF measurements. While a significant fraction of ambient particles were internal mixtures of varying degrees, single particle measurements of chemical composition allowed the identification of time periods during which the ambient ensemble was externally mixed. In some cases the chemical composition of the particles suggested a likely source. Throughout the full sampling period, the ambient ensemble was an external mixture of combustion-generated HOA particles from local sources (e.g. traffic), with number concentrations peaking during morning rush hour (04:00-08:00 LT) each day, and more processed particles of mixed composition from nonspecific sources. From 09:00-12:00 LT all particles within the ambient ensemble, including the locally produced HOA particles, became coated with NH4NO3 due to photochemical production of HNO3. The number concentration of externally mixed HOA particles remained low during daylight hours. Throughout the afternoon the OOA component dominated the organic fraction of the single particles, likely due to secondary organic aerosol formation and condensation. Single particle mass fractions of (NH4)2SO4 were lowest during the day and highest during the night. In one instance, gas-to-particle condensation of (NH4)2SO4 was observed on all measured particles within a strong SO2 plume arriving at T1 from the northwest. Particles with high NH4Cl mass fractions were identified during early morning periods. A limited number of particles (~5% of the total number) with mass spectral features characteristic of biomass burning were also identified.

Kneelike Structure in the Spectrum of the Heavy Component of Cosmic Rays Observed with KASCADE-Grande

NASA Astrophysics Data System (ADS)

Apel, W. D.; Arteaga-Velázquez, J. C.; Bekk, K.; Bertaina, M.; Blümer, J.; Bozdog, H.; Brancus, I. M.; Buchholz, P.; Cantoni, E.; Chiavassa, A.; Cossavella, F.; Daumiller, K.; de Souza, V.; di Pierro, F.; Doll, P.; Engel, R.; Engler, J.; Finger, M.; Fuhrmann, D.; Ghia, P. L.; Gils, H. J.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.; Huber, D.; Huege, T.; Isar, P. G.; Kampert, K.-H.; Kang, D.; Klages, H. O.; Link, K.; Łuczak, P.; Ludwig, M.; Mathes, H. J.; Mayer, H. J.; Melissas, M.; Milke, J.; Mitrica, B.; Morello, C.; Navarra, G.; Oehlschläger, J.; Ostapchenko, S.; Over, S.; Palmieri, N.; Petcu, M.; Pierog, T.; Rebel, H.; Roth, M.; Schieler, H.; Schröder, F. G.; Sima, O.; Toma, G.; Trinchero, G. C.; Ulrich, H.; Weindl, A.; Wochele, J.; Wommer, M.; Zabierowski, J.

2011-10-01

We report the observation of a steepening in the cosmic ray energy spectrum of heavy primary particles at about 8×1016eV. This structure is also seen in the all-particle energy spectrum, but is less significant. Whereas the “knee” of the cosmic ray spectrum at 3-5×1015eV was assigned to light primary masses by the KASCADE experiment, the new structure found by the KASCADE-Grande experiment is caused by heavy primaries. The result is obtained by independent measurements of the charged particle and muon components of the secondary particles of extensive air showers in the primary energy range of 1016 to 1018eV. The data are analyzed on a single-event basis taking into account also the correlation of the two observables.

A Novel Prediction Method about Single Components of Analog Circuits Based on Complex Field Modeling

PubMed Central

Tian, Shulin; Yang, Chenglin

2014-01-01

Few researches pay attention to prediction about analog circuits. The few methods lack the correlation with circuit analysis during extracting and calculating features so that FI (fault indicator) calculation often lack rationality, thus affecting prognostic performance. To solve the above problem, this paper proposes a novel prediction method about single components of analog circuits based on complex field modeling. Aiming at the feature that faults of single components hold the largest number in analog circuits, the method starts with circuit structure, analyzes transfer function of circuits, and implements complex field modeling. Then, by an established parameter scanning model related to complex field, it analyzes the relationship between parameter variation and degeneration of single components in the model in order to obtain a more reasonable FI feature set via calculation. According to the obtained FI feature set, it establishes a novel model about degeneration trend of analog circuits' single components. At last, it uses particle filter (PF) to update parameters for the model and predicts remaining useful performance (RUP) of analog circuits' single components. Since calculation about the FI feature set is more reasonable, accuracy of prediction is improved to some extent. Finally, the foregoing conclusions are verified by experiments. PMID:25147853

Single virus particle mass detection using microresonators with nanoscale thickness

NASA Astrophysics Data System (ADS)

Gupta, A.; Akin, D.; Bashir, R.

2004-03-01

In this letter, we present the microfabrication and application of arrays of silicon cantilever beams as microresonator sensors with nanoscale thickness to detect the mass of individual virus particles. The dimensions of the fabricated cantilever beams were in the range of 4-5 μm in length, 1-2 μm in width and 20-30 nm in thickness. The virus particles we used in the study were vaccinia virus, which is a member of the Poxviridae family and forms the basis of the smallpox vaccine. The frequency spectra of the cantilever beams, due to thermal and ambient noise, were measured using a laser Doppler vibrometer under ambient conditions. The change in resonant frequency as a function of the virus particle mass binding on the cantilever beam surface forms the basis of the detection scheme. We have demonstrated the detection of a single vaccinia virus particle with an average mass of 9.5 fg. These devices can be very useful as components of biosensors for the detection of airborne virus particles.

Characterization of individual ice residual particles by the single droplet freezing method: a case study in the Asian dust outflow region

NASA Astrophysics Data System (ADS)

Iwata, Ayumi; Matsuki, Atsushi

2018-02-01

In order to better characterize ice nucleating (IN) aerosol particles in the atmosphere, we investigated the chemical composition, mixing state, and morphology of atmospheric aerosols that nucleate ice under conditions relevant for mixed-phase clouds. Five standard mineral dust samples (quartz, K-feldspar, Na-feldspar, Arizona test dust, and Asian dust source particles) were compared with actual aerosol particles collected from the west coast of Japan (the city of Kanazawa) during Asian dust events in February and April 2016. Following droplet activation by particles deposited on a hydrophobic Si (silicon) wafer substrate under supersaturated air, individual IN particles were located using an optical microscope by gradually cooling the temperature to -30 °C. For the aerosol samples, both the IN active particles and non-active particles were analyzed individually by atomic force microscopy (AFM), micro-Raman spectroscopy, and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX). Heterogeneous ice nucleation in all standard mineral dust samples tested in this study was observed at consistently higher temperatures (e.g., -22.2 to -24.2 °C with K-feldspar) than the homogeneous freezing temperature (-36.5 °C). Meanwhile, most of the IN active atmospheric particles formed ice below -28 °C, i.e., at lower temperatures than the standard mineral dust samples of pure components. The most abundant IN active particles above -30 °C were predominantly irregular solid particles that showed clay mineral characteristics (or mixtures of several mineral components). Other than clay, Ca-rich particles internally mixed with other components, such as sulfate, were also regarded as IN active particle types. Moreover, sea salt particles were predominantly found in the non-active fraction, and internal mixing with sea salt clearly acted as a significant inhibiting agent for the ice nucleation activity of mineral dust particles. Also, relatively pure or fresh calcite, Ca(NO3)2, and (NH4)2SO4 particles were more often found in the non-active fraction. In this study, we demonstrated the capability of the combined single droplet freezing method and thorough individual particle analysis to characterize the ice nucleation activity of atmospheric aerosols. We also found that dramatic changes in the particle mixing states during long-range transport had a complex effect on the ice nucleation activity of the host aerosol particles. A case study in the Asian dust outflow region highlighted the need to consider particle mixing states, which can dramatically influence ice nucleation activity.

Criticality of Low-Energy Protons in Single-Event Effects Testing of Highly-Scaled Technologies

NASA Technical Reports Server (NTRS)

Pellish, Jonathan A.; Marshall, Paul W.; Rodbell, Kenneth P.; Gordon, Michael S.; LaBel, Kenneth A.; Schwank, James R.; Dodds, Nathaniel A.; Castaneda, Carlos M.; Berg, Melanie D.; Kim, Hak S.;

Formation of a new archetypal Metal-Organic Framework from a simple monatomic liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metere, Alfredo, E-mail: alfredo.metere@mmk.su.se; Oleynikov, Peter; Dzugutov, Mikhail

2014-12-21

We report a molecular-dynamics simulation of a single-component system of particles interacting via a spherically symmetric potential that is found to form, upon cooling from a liquid state, a low-density porous crystalline phase. Its structure analysis demonstrates that the crystal can be described by a net with a topology that belongs to the class of topologies characteristic of the Metal-Organic Frameworks (MOFs). The observed net is new, and it is now included in the Reticular Chemistry Structure Resource database. The observation that a net topology characteristic of MOF crystals, which are known to be formed by a coordination-driven self-assembly process,more » can be reproduced by a thermodynamically stable configuration of a simple single-component system of particles opens a possibility of using these models in studies of MOF nets. It also indicates that structures with MOF topology, as well as other low-density porous crystalline structures can possibly be produced in colloidal systems of spherical particles, with an appropriate tuning of interparticle interaction.« less

Size-resolved chemical composition, effective density, and optical properties of biomass burning particles

NASA Astrophysics Data System (ADS)

Zhai, Jinghao; Lu, Xiaohui; Li, Ling; Zhang, Qi; Zhang, Ci; Chen, Hong; Yang, Xin; Chen, Jianmin

2017-06-01

Biomass burning aerosol has an important impact on the global radiative budget. A better understanding of the correlations between the mixing states of biomass burning particles and their optical properties is the goal of a number of current studies. In this work, the effective density, chemical composition, and optical properties of rice straw burning particles in the size range of 50-400 nm were measured using a suite of online methods. We found that the major components of particles produced by burning rice straw included black carbon (BC), organic carbon (OC), and potassium salts, but the mixing states of particles were strongly size dependent. Particles of 50 nm had the smallest effective density (1.16 g cm-3) due to a relatively large proportion of aggregate BC. The average effective densities of 100-400 nm particles ranged from 1.35 to 1.51 g cm-3 with OC and inorganic salts as dominant components. Both density distribution and single-particle mass spectrometry showed more complex mixing states in larger particles. Upon heating, the separation of the effective density distribution modes confirmed the external mixing state of less-volatile BC or soot and potassium salts. The size-resolved optical properties of biomass burning particles were investigated at two wavelengths (λ = 450 and 530 nm). The single-scattering albedo (SSA) showed the lowest value for 50 nm particles (0.741 ± 0.007 and 0.889 ± 0.006) because of the larger proportion of BC content. Brown carbon played an important role for the SSA of 100-400 nm particles. The Ångström absorption exponent (AAE) values for all particles were above 1.6, indicating the significant presence of brown carbon in all sizes. Concurrent measurements in our work provide a basis for discussing the physicochemical properties of biomass burning aerosol and its effects on the global climate and atmospheric environment.

Application of two-component phase Doppler interferometry to the measurement of particle size, mass flux, and velocities in two-phase flows

NASA Technical Reports Server (NTRS)

Mcdonell, V. G.; Samuelsen, G. S.

1989-01-01

Two-component phase Doppler interferometry is described, along with its application for the spatially-resolved measurements of particle size, velocity, and mass flux as well as continuous phase velocity. This technique measures single particle events at a point in the flow; droplet size is deduced from the spatial phase shift of the Doppler signal. Particle size influence and discrimination of continuous and discrete phases are among issues covered. Applications are presented for four cases: an example of the discrimination of two sizes of glass beads in a jet flow; a demonstration of the discrimination of phases in a spray field; an assessment of atomizer symmetry with respect to fuel distribution; and a characterization of a droplet field in a reacting spray. It is noted that the above technique is especially powerful in delineating droplet interactions in the swirling, complex flows typical of realistic systems.

The applicability of physical optics in the millimetre and sub-millimetre spectral region. Part II: Application to a three-component model of ice cloud and its evaluation against the bulk single-scattering properties of various other aggregate models

NASA Astrophysics Data System (ADS)

Baran, Anthony J.; Ishimoto, Hiroshi; Sourdeval, Odran; Hesse, Evelyn; Harlow, Chawn

2018-02-01

The bulk single-scattering properties of various randomly oriented aggregate ice crystal models are compared and contrasted at a number of frequencies between 89 and 874 GHz. The model ice particles consist of the ten-branched plate aggregate, five-branched plate aggregate, eight-branched hexagonal aggregate, Voronoi ice aggregate, six-branched hollow bullet rosette, hexagonal column of aspect ratio unity, and the ten-branched hexagonal aggregate. The bulk single-scattering properties of the latter two ice particle models have been calculated using the light scattering methods described in Part I, which represent the two most extreme members of an ensemble model of cirrus ice crystals. In Part I, it was shown that the method of physical optics could be combined with the T-matrix at a size parameter of about 18 to compute the bulk integral ice optical properties and the phase function in the microwave to sufficient accuracy to be of practical value. Here, the bulk single-scattering properties predicted by the two ensemble model members and the Voronoi model are shown to generally bound those of all other models at frequencies between 89 and 874 GHz, thus representing a three-component model of ice cloud that can be generally applied to the microwave, rather than using many differing ice particle models. Moreover, the Voronoi model and hollow bullet rosette scatter similarly to each other in the microwave. Furthermore, from the various comparisons, the importance of assumed shapes of the particle size distribution as well as cm-sized ice aggregates is demonstrated.

Phase-factor-dependent symmetries and quantum phases in a three-level cavity QED system.

PubMed

Fan, Jingtao; Yu, Lixian; Chen, Gang; Jia, Suotang

2016-05-03

Unlike conventional two-level particles, three-level particles may support some unitary-invariant phase factors when they interact coherently with a single-mode quantized light field. To gain a better understanding of light-matter interaction, it is thus necessary to explore the phase-factor-dependent physics in such a system. In this report, we consider the collective interaction between degenerate V-type three-level particles and a single-mode quantized light field, whose different components are labeled by different phase factors. We mainly establish an important relation between the phase factors and the symmetry or symmetry-broken physics. Specifically, we find that the phase factors affect dramatically the system symmetry. When these symmetries are breaking separately, rich quantum phases emerge. Finally, we propose a possible scheme to experimentally probe the predicted physics of our model. Our work provides a way to explore phase-factor-induced nontrivial physics by introducing additional particle levels.

First-order reversal curves of single domain particles: diluted random assemblages and chains

NASA Astrophysics Data System (ADS)

Egli, R.

2009-04-01

Exact magnetic models can be used to calculate first-order reversal curves (FORC) of single domain (SD) particle assemblages, as shown by Newell [2005] for the case of isolated Stoner-Wohlfarth particles. After overcoming experimental difficulties, a FORC diagram sharing many similarities to Newell's model has been measured on a lake sediment sample (see A.P. Chen et al., "Quantification of magnetofossils using first-order reversal curves", EGU General Assembly 2009, Abstracts Vol. 11, EGU2009-10719). This sample contains abundant magnetofossils, as shown by coercivity analysis and electron microscopy, therefore suggesting that well dispersed, intact magnetosome chains are the main SD carriers. Subtle differences between the reversible and the irreversible contributions of the measured FORC distribution suggest that magnetosome chains might not be correctly described by the Stoner-Wohlfarth model. To better understand the hysteresis properties of such chains, a simple magnetic model has been implemented, taking dipole-dipole interactions between particles within the same chain into account. The model results depend on the magnetosome elongation, the number of magnetosomes in a chain, and the gap between them. If the chain axis is subparallel to the applied field, the magnetic moment reverses by a pseudo-fanning mode, which is replaced by a pseudo-coherent rotation mode at greater angles. These reversal modes are intrinsically different from coherent rotation assumed Stoner-Wohlfarth model, resulting in FORC diagrams with a smaller reversible component. On the other hand, isolated authigenic SD particles can precipitate in the sediment matrix, as it might occur for pedogenic magnetite. In this case, an assembly of randomly located particles provides a possible model for the resulting FORC diagram. If the concentration of the particles is small, each particle is affected by a random interaction field whose statistical distribution can be calculated from first principles. In this case, the irreversible component of the FORC diagram, which is described by a Dirac delta function in the non-interacting case, converts into a continuous function that directly reflects the distribution of interaction fields. Such models provide a way to identify and characterize authigenic SD particles in sediments, and in some case allow one to isolate their magnetic contribution from that of other magnetic components. Newell, A.J. (2005), A high-precision model of first-order reversal curve (FORC) functions for single-domain ferromagnets with uniaxial anisotropy, Gechem. Geophys. Geosyst., 6, Q05010, doi:10.1029/2004GC00877.

Optical potential from first principles

DOE PAGES

Rotureau, J.; Danielewicz, P.; Hagen, G.; ...

2017-02-15

Here, we develop a method to construct a microscopic optical potential from chiral interactions for nucleon-nucleus scattering. The optical potential is constructed by combining the Green’s function approach with the coupled-cluster method. To deal with the poles of the Green’s function along the real energy axis we employ a Berggren basis in the complex energy plane combined with the Lanczos method. Using this approach, we perform a proof-of-principle calculation of the optical potential for the elastic neutron scattering on 16O. For the computation of the ground-state of 16O, we use the coupled-cluster method in the singles-and-doubles approximation, while for themore » A ±1 nuclei we use particle-attached/removed equation-of-motion method truncated at two-particle-one-hole and one-particle-two-hole excitations, respectively. We verify the convergence of the optical potential and scattering phase shifts with respect to the model-space size and the number of discretized complex continuum states. We also investigate the absorptive component of the optical potential (which reflects the opening of inelastic channels) by computing its imaginary volume integral and find an almost negligible absorptive component at low-energies. To shed light on this result, we computed excited states of 16O using equation-of-motion coupled-cluster method with singles-and- doubles excitations and we found no low-lying excited states below 10 MeV. Furthermore, most excited states have a dominant two-particle-two-hole component, making higher-order particle-hole excitations necessary to achieve a precise description of these core-excited states. We conclude that the reduced absorption at low-energies can be attributed to the lack of correlations coming from the low-order cluster truncation in the employed coupled-cluster method.« less

Means for the focusing and acceleration of parallel beams of charged particles. [Patent application

DOEpatents

Maschke, A.W.

1980-09-23

Apparatus for focusing beams of charged particles comprising planar arrays of electrostatic quadrupoles. The array may be assembled from a single component which comprises a support plate containing uniform rows of poles. Each pole is separated by a hole through the plate designed to pass a beam. Two such plates may be positioned with their poles intermeshed to form a plurality of quadrupoles.

Alignment of cryo-EM movies of individual particles by optimization of image translations.

PubMed

Rubinstein, John L; Brubaker, Marcus A

2015-11-01

Direct detector device (DDD) cameras have revolutionized single particle electron cryomicroscopy (cryo-EM). In addition to an improved camera detective quantum efficiency, acquisition of DDD movies allows for correction of movement of the specimen, due to both instabilities in the microscope specimen stage and electron beam-induced movement. Unlike specimen stage drift, beam-induced movement is not always homogeneous within an image. Local correlation in the trajectories of nearby particles suggests that beam-induced motion is due to deformation of the ice layer. Algorithms have already been described that can correct movement for large regions of frames and for >1 MDa protein particles. Another algorithm allows individual <1 MDa protein particle trajectories to be estimated, but requires rolling averages to be calculated from frames and fits linear trajectories for particles. Here we describe an algorithm that allows for individual <1 MDa particle images to be aligned without frame averaging or linear trajectories. The algorithm maximizes the overall correlation of the shifted frames with the sum of the shifted frames. The optimum in this single objective function is found efficiently by making use of analytically calculated derivatives of the function. To smooth estimates of particle trajectories, rapid changes in particle positions between frames are penalized in the objective function and weighted averaging of nearby trajectories ensures local correlation in trajectories. This individual particle motion correction, in combination with weighting of Fourier components to account for increasing radiation damage in later frames, can be used to improve 3-D maps from single particle cryo-EM. Copyright © 2015 Elsevier Inc. All rights reserved.

Chemical composition of individual aerosol particles in workplace air during production of manganese alloys.

PubMed

Gunst, S; Weinbruch, S; Wentzel, M; Ortner, H M; Skogstad, A; Hetland, S; Thomassen, Y

2000-02-01

Aerosol particle samples were collected at ELKEM ASA ferromanganese (FeMn) and silicomanganese (SiMn) smelters at Porsgrunn, Norway, during different production steps: raw material mixing, welding of protective steel casings, tapping of FeMn and slag, crane operation moving the ladles with molten metal, operation of the Metal Oxygen Refinement (MOR) reactor and casting of SiMn. Aerosol fractions were assessed for the analysis of the bulk elemental composition as well as for individual particle analysis. The bulk elemental composition was determined by inductively coupled plasma atomic emission spectrometry. For individual particle analysis, an electron microprobe was used in combination with wavelength-dispersive techniques. Most particles show a complex composition and cannot be attributed to a single phase. Therefore, the particles were divided into six groups according to their chemical composition: Group I, particles containing mainly metallic Fe and/or Mn; Group II, slag particles containing mainly Fe and/or Mn oxides; Group III, slag particles consisting predominantly of oxidized flux components such as Si, Al, Mg, Ca, Na and K; Group IV, particles consisting mainly of carbon; Group V, mixtures of particles from Groups II, III and IV; Group VI, mixtures of particles from Groups II and III. In raw material mixing, particles originating from the Mn ores were mostly found. In the welding of steel casings, most particles were assigned to Group II, Mn and Fe oxides. During the tapping of slag and metal, mostly slag particles from Group III were found (oxides of the flux components). During movement of the ladles, most particles came from Group II. At the MOR reactor, most of the particles belonged to the slag phase consisting of the flux components (Group III). The particles collected during the casting of SiMn were mainly attributed to the slag phase (Groups III and V). Due to the compositional complexity of the particles, toxicological investigations on the kinetics of pure compounds may not be easily associated with the results of this study.

Improved Holistic Analysis of Rayleigh Waves for Single- and Multi-Offset Data: Joint Inversion of Rayleigh-Wave Particle Motion and Vertical- and Radial-Component Velocity Spectra

NASA Astrophysics Data System (ADS)

Dal Moro, Giancarlo; Moustafa, Sayed S. R.; Al-Arifi, Nassir S.

2018-01-01

Rayleigh waves often propagate according to complex mode excitation so that the proper identification and separation of specific modes can be quite difficult or, in some cases, just impossible. Furthermore, the analysis of a single component (i.e., an inversion procedure based on just one objective function) necessarily prevents solving the problems related to the non-uniqueness of the solution. To overcome these issues and define a holistic analysis of Rayleigh waves, we implemented a procedure to acquire data that are useful to define and efficiently invert the three objective functions defined from the three following "objects": the velocity spectra of the vertical- and radial-components and the Rayleigh-wave particle motion (RPM) frequency-offset data. Two possible implementations are presented. In the first case we consider classical multi-offset (and multi-component) data, while in a second possible approach we exploit the data recorded by a single three-component geophone at a fixed offset from the source. Given the simple field procedures, the method could be particularly useful for the unambiguous geotechnical exploration of large areas, where more complex acquisition procedures, based on the joint acquisition of Rayleigh and Love waves, would not be economically viable. After illustrating the different kinds of data acquisition and the data processing, the results of the proposed methodology are illustrated in a case study. Finally, a series of theoretical and practical aspects are discussed to clarify some issues involved in the overall procedure (data acquisition and processing).

ICTV Virus Taxonomy Profile: Virgaviridae

USDA-ARS?s Scientific Manuscript database

The family Virgaviridae is comprised of plant-infecting viruses with rod-shaped particles, single stranded RNA genomes with 3' terminal tRNA-like structures, and replication proteins typical of alphalike viruses. Differences in the number of genome components, genome organization and transmission m...

Multi-Component, Multi-Point Interferometric Rayleigh/Mie Doppler Velocimeter

NASA Technical Reports Server (NTRS)

Danehy, Paul M.; Lee, Joseph W.; Bivolaru, Daniel

2012-01-01

An interferometric Rayleigh scattering system was developed to enable the measurement of multiple, orthogonal velocity components at several points within very-high-speed or high-temperature flows. The velocity of a gaseous flow can be optically measured by sending laser light into the gas flow, and then measuring the scattered light signal that is returned from matter within the flow. Scattering can arise from either gas molecules within the flow itself, known as Rayleigh scattering, or from particles within the flow, known as Mie scattering. Measuring Mie scattering is the basis of all commercial laser Doppler and particle imaging velocimetry systems, but particle seeding is problematic when measuring high-speed and high-temperature flows. The velocimeter is designed to measure the Doppler shift from only Rayleigh scattering, and does not require, but can also measure, particles within the flow. The system combines a direct-view, large-optic interferometric setup that calculates the Doppler shift from fringe patterns collected with a digital camera, and a subsystem to capture and re-circulate scattered light to maximize signal density. By measuring two orthogonal components of the velocity at multiple positions in the flow volume, the accuracy and usefulness of the flow measurement increase significantly over single or nonorthogonal component approaches.

LET spectra measurements of charged particles in the P0006 experiment on LDEF

NASA Technical Reports Server (NTRS)

Benton, E. V.; Csige, I.; Oda, K.; Henke, R. P.; Frank, A. L.; Benton, E. R.; Frigo, L. A.; Parnell, T. A.; Watts, J. W., Jr.; Derrickson, J. H.

1993-01-01

Measurements are under way of the charged particle radiation environment of the Long Duration Exposure Facility (LDEF) satellite using stacks of plastic nuclear track detectors (PNTD's) placed in different locations of the satellite. In the initial work the charge, energy, and linear energy transfer (LET) spectra of charged particles were measured with CR-39 double layer PNTD's located on the west side of the satellite (Experiment P0006). Primary and secondary stopping heavy ions were measured separately from the more energetic particles. Both trapped and galactic cosmic ray (GCR) particles are included, with the latter component being dominated by relativistic iron particles. The results from the P0006 experiment will be compared with similar measurements in other locations on LDEF with different orientation and shielding conditions. The remarkably detailed investigation of the charged particle radiation environment of the LDEF satellite will lead to a better understanding of the radiation environment of the Space Station Freedom. It will enable more accurate prediction of single event upsets (SEU's) in microelectronics and, especially, more accurate assessment of the risk - contributed by different components of the radiation field (GCR's, trapped protons, secondaries and heavy recoils, etc.) - to the health and safety of crew members.

Protein secondary structure determination by constrained single-particle cryo-electron tomography.

PubMed

Bartesaghi, Alberto; Lecumberry, Federico; Sapiro, Guillermo; Subramaniam, Sriram

2012-12-05

Cryo-electron microscopy (cryo-EM) is a powerful technique for 3D structure determination of protein complexes by averaging information from individual molecular images. The resolutions that can be achieved with single-particle cryo-EM are frequently limited by inaccuracies in assigning molecular orientations based solely on 2D projection images. Tomographic data collection schemes, however, provide powerful constraints that can be used to more accurately determine molecular orientations necessary for 3D reconstruction. Here, we propose "constrained single-particle tomography" as a general strategy for 3D structure determination in cryo-EM. A key component of our approach is the effective use of images recorded in tilt series to extract high-resolution information and correct for the contrast transfer function. By incorporating geometric constraints into the refinement to improve orientational accuracy of images, we reduce model bias and overrefinement artifacts and demonstrate that protein structures can be determined at resolutions of ∼8 Å starting from low-dose tomographic tilt series. Copyright © 2012 Elsevier Ltd. All rights reserved.

Design of fluidized-bed fermentors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrews, G.F.; Przezdziecki, J.

1986-06-01

Designing a fluidized-bed bioreactor requires choosing the best support particle (if any). Effectiveness factors (proportional to reactor volumetric productivity) are derived for flocs, solid spherical supports, porous supports, and adsorbent supports. The derivation demonstrates a mathematical procedure for reducing the diffusion/uptake equations for many components (substrates and inhibitory products) to a single equation, and for identifying the limiting component. With solid supports there exists a film thickness that maximizes the effectiveness, and the design objective is to keep the film near this optimum throughout the bed. This involves consideration of the effect of support particle density and film growth onmore » bed stratification. Other considerations in packing support particles are obtaining reasonable values for bed height and diameter, minimizing mass transfer resistance between liquid and biomass, and preventing surface shear from stripping off the biomass. 20 references.« less

Spatial Variability of Sources and Mixing State of Atmospheric Particles in a Metropolitan Area.

PubMed

Ye, Qing; Gu, Peishi; Li, Hugh Z; Robinson, Ellis S; Lipsky, Eric; Kaltsonoudis, Christos; Lee, Alex K Y; Apte, Joshua S; Robinson, Allen L; Sullivan, Ryan C; Presto, Albert A; Donahue, Neil M

2018-05-30

Characterizing intracity variations of atmospheric particulate matter has mostly relied on fixed-site monitoring and quantifying variability in terms of different bulk aerosol species. In this study, we performed ground-based mobile measurements using a single-particle mass spectrometer to study spatial patterns of source-specific particles and the evolution of particle mixing state in 21 areas in the metropolitan area of Pittsburgh, PA. We selected sampling areas based on traffic density and restaurant density with each area ranging from 0.2 to 2 km 2 . Organics dominate particle composition in all of the areas we sampled while the sources of organics differ. The contribution of particles from traffic and restaurant cooking varies greatly on the neighborhood scale. We also investigate how primary and aged components in particles mix across the urban scale. Lastly we quantify and map the particle mixing state for all areas we sampled and discuss the overall pattern of mixing state evolution and its implications. We find that in the upwind and downwind of the urban areas, particles are more internally mixed while in the city center, particle mixing state shows large spatial heterogeneity that is mostly driven by emissions. This study is to our knowledge, the first study to perform fine spatial scale mapping of particle mixing state using ground-based mobile measurement and single-particle mass spectrometry.

Principal-component analysis of two-particle azimuthal correlations in PbPb and $$p\\text{Pb}$$ collisions at CMS

DOE PAGES

Sirunyan, A.M.; et al.

2017-12-05

For the first time a principle-component analysis is used to separate out different orthogonal modes of the two-particle correlation matrix from heavy ion collisions. The analysis uses data from sNN=2.76TeV PbPb and sNN=5.02TeV pPb collisions collected by the CMS experiment at the CERN Large Hadron Collider. Two-particle azimuthal correlations have been extensively used to study hydrodynamic flow in heavy ion collisions. Recently it was shown that the expected factorization of two-particle results into a product of the constituent single-particle anisotropies is broken. The new information provided by these modes may shed light on the breakdown of flow factorization in heavymore » ion collisions. The first two modes (“leading” and “subleading”) of two-particle correlations are presented for elliptical and triangular anisotropies in PbPb and pPb collisions as a function of pT over a wide range of event activity. The leading mode is found to be essentially equivalent to the anisotropy harmonic previously extracted from two-particle correlation methods. The subleading mode represents a new experimental observable and is shown to account for a large fraction of the factorization breaking recently observed at high transverse momentum. The principle-component analysis technique was also applied to multiplicity fluctuations. These also show a subleading mode. The connection of these new results to previous studies of factorization is discussed.« less

Principal-component analysis of two-particle azimuthal correlations in PbPb and pPb collisions at CMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sirunyan, Albert M; et al.

2017-08-23

For the first time a principle-component analysis is used to separate out different orthogonal modes of the two-particle correlation matrix from heavy ion collisions. The analysis uses data from sqrt(s[NN]) = 2.76 TeV PbPb and sqrt(s[NN]) = 5.02 TeV pPb collisions collected by the CMS experiment at the LHC. Two-particle azimuthal correlations have been extensively used to study hydrodynamic flow in heavy ion collisions. Recently it has been shown that the expected factorization of two-particle results into a product of the constituent single-particle anisotropies is broken. The new information provided by these modes may shed light on the breakdown ofmore » flow factorization in heavy ion collisions. The first two modes ("leading" and "subleading") of two-particle correlations are presented for elliptical and triangular anisotropies in PbPb and pPb collisions as a function of pt over a wide range of event activity. The leading mode is found to be essentially equivalent to the anisotropy harmonic previously extracted from two-particle correlation methods. The subleading mode represents a new experimental observable and is shown to account for a large fraction of the factorization breaking recently observed at high transverse momentum. The principle-component analysis technique has also been applied to multiplicity fluctuations. These also show a subleading mode. The connection of these new results to previous studies of factorization is discussed.« less

Principal-component analysis of two-particle azimuthal correlations in PbPb and p Pb collisions at CMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sirunyan, A. M.; Tumasyan, A.; Adam, W.

For the first time a principle-component analysis is used to separate out different orthogonal modes of the two-particle correlation matrix from heavy ion collisions. The analysis uses data from √ sNN = 2.76TeV PbPb and √ sNN = 5.02TeV pPb collisions collected by the CMS experiment at the CERN Large Hadron Collider. Two-particle azimuthal correlations have been extensively used to study hydrodynamic flow in heavy ion collisions. Recently it was shown that the expected factorization of two-particle results into a product of the constituent single-particle anisotropies is broken. The new information provided by these modes may shed light on themore » breakdown of flow factorization in heavy ion collisions. The first two modes (“leading” and “subleading”) of two-particle correlations are presented for elliptical and triangular anisotropies in PbPb and pPb collisions as a function of p T over a wide range of event activity. The leading mode is found to be essentially equivalent to the anisotropy harmonic previously extracted from two-particle correlation methods. The subleading mode represents a new experimental observable and is shown to account for a large fraction of the factorization breaking recently observed at high transverse momentum. The principle-component analysis technique was also applied to multiplicity fluctuations. These also show a subleading mode. As a result, the connection of these new results to previous studies of factorization is discussed.« less

Principal-component analysis of two-particle azimuthal correlations in PbPb and p Pb collisions at CMS

NASA Astrophysics Data System (ADS)

Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Grossmann, J.; Hrubec, J.; Jeitler, M.; König, A.; Krammer, N.; Krätschmer, I.; Liko, D.; Madlener, T.; Mikulec, I.; Pree, E.; Rabady, D.; Rad, N.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Spanring, M.; Spitzbart, D.; Strauss, J.; Waltenberger, W.; Wittmann, J.; Wulz, C.-E.; Zarucki, M.; Chekhovsky, V.; Mossolov, V.; Suarez Gonzalez, J.; De Wolf, E. A.; Janssen, X.; Lauwers, J.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; De Bruyn, I.; De Clercq, J.; Deroover, K.; Flouris, G.; Lowette, S.; Moortgat, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Skovpen, K.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Parijs, I.; Brun, H.; Clerbaux, B.; De Lentdecker, G.; Delannoy, H.; Fasanella, G.; Favart, L.; Goldouzian, R.; Grebenyuk, A.; Karapostoli, G.; Lenzi, T.; Luetic, J.; Maerschalk, T.; Marinov, A.; Randle-conde, A.; Seva, T.; Vander Velde, C.; Vanlaer, P.; Vannerom, D.; Yonamine, R.; Zenoni, F.; Zhang, F.; Cimmino, A.; Cornelis, T.; Dobur, D.; Fagot, A.; Gul, M.; Khvastunov, I.; Poyraz, D.; Roskas, C.; Salva, S.; Tytgat, M.; Verbeke, W.; Zaganidis, N.; Bakhshiansohi, H.; Bondu, O.; Brochet, S.; Bruno, G.; Caudron, A.; De Visscher, S.; Delaere, C.; Delcourt, M.; Francois, B.; Giammanco, A.; Jafari, A.; Komm, M.; Krintiras, G.; Lemaitre, V.; Magitteri, A.; Mertens, A.; Musich, M.; Piotrzkowski, K.; Quertenmont, L.; Vidal Marono, M.; Wertz, S.; Beliy, N.; Aldá Júnior, W. L.; Alves, F. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Hensel, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; Da Silveira, G. G.; De Jesus Damiao, D.; Fonseca De Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Melo De Almeida, M.; Mora Herrera, C.; Mundim, L.; Nogima, H.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Torres Da Silva De Araujo, F.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; Tomei, T. R. Fernandez Perez; Gregores, E. M.; Mercadante, P. G.; Moon, C. S.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Misheva, M.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Fang, W.; Gao, X.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Chen, Y.; Jiang, C. H.; Leggat, D.; Liu, Z.; Romeo, F.; Shaheen, S. M.; Spiezia, A.; Tao, J.; Wang, C.; Wang, Z.; Yazgan, E.; Zhang, H.; Zhao, J.; Ban, Y.; Chen, G.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; González Hernández, C. F.; Ruiz Alvarez, J. D.; Courbon, B.; Godinovic, N.; Lelas, D.; Puljak, I.; Ribeiro Cipriano, P. M.; Sculac, T.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Ferencek, D.; Kadija, K.; Mesic, B.; Susa, T.; Ather, M. W.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Finger, M.; Finger, M.; Carrera Jarrin, E.; Abdelalim, A. A.; Mohammed, Y.; Salama, E.; Dewanjee, R. 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T.; Meister, D.; Micheli, F.; Musella, P.; Nessi-Tedaldi, F.; Pandolfi, F.; Pata, J.; Pauss, F.; Perrin, G.; Perrozzi, L.; Quittnat, M.; Rossini, M.; Schönenberger, M.; Shchutska, L.; Starodumov, A.; Tavolaro, V. R.; Theofilatos, K.; Vesterbacka Olsson, M. L.; Wallny, R.; Zagozdzinska, A.; Zhu, D. H.; Aarrestad, T. K.; Amsler, C.; Caminada, L.; Canelli, M. F.; De Cosa, A.; Donato, S.; Galloni, C.; Hinzmann, A.; Hreus, T.; Kilminster, B.; Ngadiuba, J.; Pinna, D.; Rauco, G.; Robmann, P.; Salerno, D.; Seitz, C.; Zucchetta, A.; Candelise, V.; Doan, T. H.; Jain, Sh.; Khurana, R.; Konyushikhin, M.; Kuo, C. M.; Lin, W.; Pozdnyakov, A.; Yu, S. S.; Kumar, Arun; Chang, P.; Chao, Y.; Chen, K. F.; Chen, P. H.; Fiori, F.; Hou, W.-S.; Hsiung, Y.; Liu, Y. F.; Lu, R.-S.; Miñano Moya, M.; Paganis, E.; Psallidas, A.; Tsai, J. f.; Asavapibhop, B.; Kovitanggoon, K.; Singh, G.; Srimanobhas, N.; Adiguzel, A.; Bakirci, M. N.; Boran, F.; Cerci, S.; Damarseckin, S.; Demiroglu, Z. S.; Dozen, C.; Dumanoglu, I.; Girgis, S.; Gokbulut, G.; Guler, Y.; Hos, I.; Kangal, E. E.; Kara, O.; Kayis Topaksu, A.; Kiminsu, U.; Oglakci, M.; Onengut, G.; Ozdemir, K.; Tali, B.; Turkcapar, S.; Zorbakir, I. S.; Zorbilmez, C.; Bilin, B.; Karapinar, G.; Ocalan, K.; Yalvac, M.; Zeyrek, M.; Gülmez, E.; Kaya, M.; Kaya, O.; Tekten, S.; Yetkin, E. A.; Agaras, M. N.; Atay, S.; Cakir, A.; Cankocak, K.; Grynyov, B.; Levchuk, L.; Sorokin, P.; Aggleton, R.; Ball, F.; Beck, L.; Brooke, J. J.; Burns, D.; Clement, E.; Cussans, D.; Flacher, H.; Goldstein, J.; Grimes, M.; Heath, G. P.; Heath, H. F.; Jacob, J.; Kreczko, L.; Lucas, C.; Newbold, D. M.; Paramesvaran, S.; Poll, A.; Sakuma, T.; Seif El Nasr-storey, S.; Smith, D.; Smith, V. J.; Belyaev, A.; Brew, C.; Brown, R. M.; Calligaris, L.; Cieri, D.; Cockerill, D. J. A.; Coughlan, J. A.; Harder, K.; Harper, S.; Olaiya, E.; Petyt, D.; Shepherd-Themistocleous, C. H.; Thea, A.; Tomalin, I. R.; Williams, T.; Baber, M.; Bainbridge, R.; Breeze, S.; Buchmuller, O.; Bundock, A.; Casasso, S.; Citron, M.; Colling, D.; Corpe, L.; Dauncey, P.; Davies, G.; De Wit, A.; Della Negra, M.; Di Maria, R.; Dunne, P.; Elwood, A.; Futyan, D.; Haddad, Y.; Hall, G.; Iles, G.; James, T.; Lane, R.; Laner, C.; Lyons, L.; Magnan, A.-M.; Malik, S.; Mastrolorenzo, L.; Matsushita, T.; Nash, J.; Nikitenko, A.; Pela, J.; Pesaresi, M.; Raymond, D. M.; Richards, A.; Rose, A.; Scott, E.; Seez, C.; Shtipliyski, A.; Summers, S.; Tapper, A.; Uchida, K.; Vazquez Acosta, M.; Virdee, T.; Winterbottom, D.; Wright, J.; Zenz, S. C.; Cole, J. E.; Hobson, P. R.; Khan, A.; Kyberd, P.; Reid, I. D.; Symonds, P.; Teodorescu, L.; Turner, M.; Borzou, A.; Call, K.; Dittmann, J.; Hatakeyama, K.; Liu, H.; Pastika, N.; Bartek, R.; Dominguez, A.; Buccilli, A.; Cooper, S. I.; Henderson, C.; Rumerio, P.; West, C.; Arcaro, D.; Avetisyan, A.; Bose, T.; Gastler, D.; Rankin, D.; Richardson, C.; Rohlf, J.; Sulak, L.; Zou, D.; Benelli, G.; Cutts, D.; Garabedian, A.; Hakala, J.; Heintz, U.; Hogan, J. M.; Kwok, K. H. M.; Laird, E.; Landsberg, G.; Mao, Z.; Narain, M.; Pazzini, J.; Piperov, S.; Sagir, S.; Syarif, R.; Yu, D.; Band, R.; Brainerd, C.; Burns, D.; Calderon De La Barca Sanchez, M.; Chertok, M.; Conway, J.; Conway, R.; Cox, P. T.; Erbacher, R.; Flores, C.; Funk, G.; Gardner, M.; Ko, W.; Lander, R.; Mclean, C.; Mulhearn, M.; Pellett, D.; Pilot, J.; Shalhout, S.; Shi, M.; Smith, J.; Squires, M.; Stolp, D.; Tos, K.; Tripathi, M.; Wang, Z.; Bachtis, M.; Bravo, C.; Cousins, R.; Dasgupta, A.; Florent, A.; Hauser, J.; Ignatenko, M.; Mccoll, N.; Saltzberg, D.; Schnaible, C.; Valuev, V.; Bouvier, E.; Burt, K.; Clare, R.; Ellison, J.; Gary, J. W.; Ghiasi Shirazi, S. M. A.; Hanson, G.; Heilman, J.; Jandir, P.; Kennedy, E.; Lacroix, F.; Long, O. R.; Olmedo Negrete, M.; Paneva, M. I.; Shrinivas, A.; Si, W.; Wei, H.; Wimpenny, S.; Yates, B. R.; Branson, J. G.; Cerati, G. B.; Cittolin, S.; Derdzinski, M.; Gerosa, R.; Hashemi, B.; Holzner, A.; Klein, D.; Kole, G.; Krutelyov, V.; Letts, J.; Macneill, I.; Masciovecchio, M.; Olivito, D.; Padhi, S.; Pieri, M.; Sani, M.; Sharma, V.; Simon, S.; Tadel, M.; Vartak, A.; Wasserbaech, S.; Wood, J.; Würthwein, F.; Yagil, A.; Zevi Della Porta, G.; Amin, N.; Bhandari, R.; Bradmiller-Feld, J.; Campagnari, C.; Dishaw, A.; Dutta, V.; Franco Sevilla, M.; George, C.; Golf, F.; Gouskos, L.; Gran, J.; Heller, R.; Incandela, J.; Mullin, S. D.; Ovcharova, A.; Qu, H.; Richman, J.; Stuart, D.; Suarez, I.; Yoo, J.; Anderson, D.; Bendavid, J.; Bornheim, A.; Lawhorn, J. M.; Newman, H. B.; Nguyen, T.; Pena, C.; Spiropulu, M.; Vlimant, J. R.; Xie, S.; Zhang, Z.; Zhu, R. Y.; Andrews, M. B.; Ferguson, T.; Mudholkar, T.; Paulini, M.; Russ, J.; Sun, M.; Vogel, H.; Vorobiev, I.; Weinberg, M.; Cumalat, J. P.; Ford, W. T.; Jensen, F.; Johnson, A.; Krohn, M.; Leontsinis, S.; Mulholland, T.; Stenson, K.; Wagner, S. R.; Alexander, J.; Chaves, J.; Chu, J.; Dittmer, S.; Mcdermott, K.; Mirman, N.; Patterson, J. R.; Rinkevicius, A.; Ryd, A.; Skinnari, L.; Soffi, L.; Tan, S. M.; Tao, Z.; Thom, J.; Tucker, J.; Wittich, P.; Zientek, M.; Abdullin, S.; Albrow, M.; Apollinari, G.; Apresyan, A.; Apyan, A.; Banerjee, S.; Bauerdick, L. A. T.; Beretvas, A.; Berryhill, J.; Bhat, P. C.; Bolla, G.; Burkett, K.; Butler, J. N.; Canepa, A.; Cheung, H. W. K.; Chlebana, F.; Cremonesi, M.; Duarte, J.; Elvira, V. D.; Freeman, J.; Gecse, Z.; Gottschalk, E.; Gray, L.; Green, D.; Grünendahl, S.; Gutsche, O.; Harris, R. M.; Hasegawa, S.; Hirschauer, J.; Hu, Z.; Jayatilaka, B.; Jindariani, S.; Johnson, M.; Joshi, U.; Klima, B.; Kreis, B.; Lammel, S.; Lincoln, D.; Lipton, R.; Liu, M.; Liu, T.; Lopes De Sá, R.; Lykken, J.; Maeshima, K.; Magini, N.; Marraffino, J. M.; Maruyama, S.; Mason, D.; McBride, P.; Merkel, P.; Mrenna, S.; Nahn, S.; O'Dell, V.; Pedro, K.; Prokofyev, O.; Rakness, G.; Ristori, L.; Schneider, B.; Sexton-Kennedy, E.; Soha, A.; Spalding, W. J.; Spiegel, L.; Stoynev, S.; Strait, J.; Strobbe, N.; Taylor, L.; Tkaczyk, S.; Tran, N. V.; Uplegger, L.; Vaandering, E. W.; Vernieri, C.; Verzocchi, M.; Vidal, R.; Wang, M.; Weber, H. A.; Whitbeck, A.; Acosta, D.; Avery, P.; Bortignon, P.; Brinkerhoff, A.; Carnes, A.; Carver, M.; Curry, D.; Das, S.; Field, R. D.; Furic, I. K.; Konigsberg, J.; Korytov, A.; Kotov, K.; Ma, P.; Matchev, K.; Mei, H.; Mitselmakher, G.; Rank, D.; Sperka, D.; Terentyev, N.; Thomas, L.; Wang, J.; Wang, S.; Yelton, J.; Joshi, Y. R.; Linn, S.; Markowitz, P.; Martinez, G.; Rodriguez, J. L.; Ackert, A.; Adams, T.; Askew, A.; Hagopian, S.; Hagopian, V.; Johnson, K. F.; Kolberg, T.; Perry, T.; Prosper, H.; Santra, A.; Yohay, R.; Baarmand, M. M.; Bhopatkar, V.; Colafranceschi, S.; Hohlmann, M.; Noonan, D.; Roy, T.; Yumiceva, F.; Adams, M. R.; Apanasevich, L.; Berry, D.; Betts, R. R.; Cavanaugh, R.; Chen, X.; Evdokimov, O.; Gerber, C. E.; Hangal, D. A.; Hofman, D. J.; Jung, K.; Kamin, J.; Sandoval Gonzalez, I. D.; Tonjes, M. B.; Trauger, H.; Varelas, N.; Wang, H.; Wu, Z.; Zhang, J.; Bilki, B.; Clarida, W.; Dilsiz, K.; Durgut, S.; Gandrajula, R. P.; Haytmyradov, M.; Khristenko, V.; Merlo, J.-P.; Mermerkaya, H.; Mestvirishvili, A.; Moeller, A.; Nachtman, J.; Ogul, H.; Onel, Y.; Ozok, F.; Penzo, A.; Snyder, C.; Tiras, E.; Wetzel, J.; Yi, K.; Blumenfeld, B.; Cocoros, A.; Eminizer, N.; Fehling, D.; Feng, L.; Gritsan, A. V.; Maksimovic, P.; Roskes, J.; Sarica, U.; Swartz, M.; Xiao, M.; You, C.; Al-bataineh, A.; Baringer, P.; Bean, A.; Boren, S.; Bowen, J.; Castle, J.; Khalil, S.; Kropivnitskaya, A.; Majumder, D.; Mcbrayer, W.; Murray, M.; Royon, C.; Sanders, S.; Schmitz, E.; Stringer, R.; Tapia Takaki, J. D.; Wang, Q.; Ivanov, A.; Kaadze, K.; Maravin, Y.; Mohammadi, A.; Saini, L. K.; Skhirtladze, N.; Toda, S.; Rebassoo, F.; Wright, D.; Anelli, C.; Baden, A.; Baron, O.; Belloni, A.; Calvert, B.; Eno, S. C.; Ferraioli, C.; Hadley, N. J.; Jabeen, S.; Jeng, G. Y.; Kellogg, R. G.; Kunkle, J.; Mignerey, A. C.; Ricci-Tam, F.; Shin, Y. H.; Skuja, A.; Tonwar, S. C.; Abercrombie, D.; Allen, B.; Azzolini, V.; Barbieri, R.; Baty, A.; Bi, R.; Brandt, S.; Busza, W.; Cali, I. A.; D'Alfonso, M.; Demiragli, Z.; Gomez Ceballos, G.; Goncharov, M.; Hsu, D.; Iiyama, Y.; Innocenti, G. M.; Klute, M.; Kovalskyi, D.; Lai, Y. S.; Lee, Y.-J.; Levin, A.; Luckey, P. D.; Maier, B.; Marini, A. C.; Mcginn, C.; Mironov, C.; Narayanan, S.; Niu, X.; Paus, C.; Roland, C.; Roland, G.; Salfeld-Nebgen, J.; Stephans, G. S. F.; Tatar, K.; Velicanu, D.; Wang, J.; Wang, T. W.; Wyslouch, B.; Benvenuti, A. C.; Chatterjee, R. M.; Evans, A.; Hansen, P.; Kalafut, S.; Kubota, Y.; Lesko, Z.; Mans, J.; Nourbakhsh, S.; Ruckstuhl, N.; Rusack, R.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bloom, K.; Claes, D. R.; Fangmeier, C.; Gonzalez Suarez, R.; Kamalieddin, R.; Kravchenko, I.; Monroy, J.; Siado, J. E.; Snow, G. R.; Stieger, B.; Alyari, M.; Dolen, J.; Godshalk, A.; Harrington, C.; Iashvili, I.; Nguyen, D.; Parker, A.; Rappoccio, S.; Roozbahani, B.; Alverson, G.; Barberis, E.; Hortiangtham, A.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Teixeira De Lima, R.; Trocino, D.; Wang, R.-J.; Wood, D.; Bhattacharya, S.; Charaf, O.; Hahn, K. A.; Mucia, N.; Odell, N.; Pollack, B.; Schmitt, M. H.; Sung, K.; Trovato, M.; Velasco, M.; Dev, N.; Hildreth, M.; Hurtado Anampa, K.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Loukas, N.; Marinelli, N.; Meng, F.; Mueller, C.; Musienko, Y.; Planer, M.; Reinsvold, A.; Ruchti, R.; Smith, G.; Taroni, S.; Wayne, M.; Wolf, M.; Woodard, A.; Alimena, J.; Antonelli, L.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Francis, B.; Hart, A.; Hill, C.; Ji, W.; Liu, B.; Luo, W.; Puigh, D.; Winer, B. L.; Wulsin, H. W.; Benaglia, A.; Cooperstein, S.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Lange, D.; Luo, J.; Marlow, D.; Mei, K.; Ojalvo, I.; Olsen, J.; Palmer, C.; Piroué, P.; Stickland, D.; Svyatkovskiy, A.; Tully, C.; Malik, S.; Norberg, S.; Barker, A.; Barnes, V. E.; Folgueras, S.; Gutay, L.; Jha, M. K.; Jones, M.; Jung, A. W.; Khatiwada, A.; Miller, D. H.; Neumeister, N.; Schulte, J. F.; Sun, J.; Wang, F.; Xie, W.; Cheng, T.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Chen, Z.; Ecklund, K. M.; Geurts, F. J. M.; Guilbaud, M.; Li, W.; Michlin, B.; Northup, M.; Padley, B. P.; Roberts, J.; Rorie, J.; Tu, Z.; Zabel, J.; Bodek, A.; de Barbaro, P.; Demina, R.; Duh, Y. t.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Han, J.; Hindrichs, O.; Khukhunaishvili, A.; Lo, K. H.; Tan, P.; Verzetti, M.; Ciesielski, R.; Goulianos, K.; Mesropian, C.; Agapitos, A.; Chou, J. P.; Gershtein, Y.; Gómez Espinosa, T. A.; Halkiadakis, E.; Heindl, M.; Hughes, E.; Kaplan, S.; Kunnawalkam Elayavalli, R.; Kyriacou, S.; Lath, A.; Montalvo, R.; Nash, K.; Osherson, M.; Saka, H.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Foerster, M.; Heideman, J.; Riley, G.; Rose, K.; Spanier, S.; Thapa, K.; Bouhali, O.; Castaneda Hernandez, A.; Celik, A.; Dalchenko, M.; De Mattia, M.; Delgado, A.; Dildick, S.; Eusebi, R.; Gilmore, J.; Huang, T.; Kamon, T.; Mueller, R.; Pakhotin, Y.; Patel, R.; Perloff, A.; Perniè, L.; Rathjens, D.; Safonov, A.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Damgov, J.; De Guio, F.; Dudero, P. R.; Faulkner, J.; Gurpinar, E.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Peltola, T.; Undleeb, S.; Volobouev, I.; Wang, Z.; Greene, S.; Gurrola, A.; Janjam, R.; Johns, W.; Maguire, C.; Melo, A.; Ni, H.; Sheldon, P.; Tuo, S.; Velkovska, J.; Xu, Q.; Arenton, M. W.; Barria, P.; Cox, B.; Hirosky, R.; Ledovskoy, A.; Li, H.; Neu, C.; Sinthuprasith, T.; Sun, X.; Wang, Y.; Wolfe, E.; Xia, F.; Clarke, C.; Harr, R.; Karchin, P. E.; Sturdy, J.; Zaleski, S.; Buchanan, J.; Caillol, C.; Dasu, S.; Dodd, L.; Duric, S.; Gomber, B.; Grothe, M.; Herndon, M.; Hervé, A.; Hussain, U.; Klabbers, P.; Lanaro, A.; Levine, A.; Long, K.; Loveless, R.; Pierro, G. A.; Polese, G.; Ruggles, T.; Savin, A.; Smith, N.; Smith, W. H.; Taylor, D.; Woods, N.; CMS Collaboration

2017-12-01

For the first time a principle-component analysis is used to separate out different orthogonal modes of the two-particle correlation matrix from heavy ion collisions. The analysis uses data from √{sNN}=2.76 TeV PbPb and √{sNN}=5.02 TeV p Pb collisions collected by the CMS experiment at the CERN Large Hadron Collider. Two-particle azimuthal correlations have been extensively used to study hydrodynamic flow in heavy ion collisions. Recently it was shown that the expected factorization of two-particle results into a product of the constituent single-particle anisotropies is broken. The new information provided by these modes may shed light on the breakdown of flow factorization in heavy ion collisions. The first two modes ("leading" and "subleading") of two-particle correlations are presented for elliptical and triangular anisotropies in PbPb and p Pb collisions as a function of pT over a wide range of event activity. The leading mode is found to be essentially equivalent to the anisotropy harmonic previously extracted from two-particle correlation methods. The subleading mode represents a new experimental observable and is shown to account for a large fraction of the factorization breaking recently observed at high transverse momentum. The principle-component analysis technique was also applied to multiplicity fluctuations. These also show a subleading mode. The connection of these new results to previous studies of factorization is discussed.

Principal-component analysis of two-particle azimuthal correlations in PbPb and p Pb collisions at CMS

DOE PAGES

Sirunyan, A. M.; Tumasyan, A.; Adam, W.; ...

2017-12-05

For the first time a principle-component analysis is used to separate out different orthogonal modes of the two-particle correlation matrix from heavy ion collisions. The analysis uses data from √ sNN = 2.76TeV PbPb and √ sNN = 5.02TeV pPb collisions collected by the CMS experiment at the CERN Large Hadron Collider. Two-particle azimuthal correlations have been extensively used to study hydrodynamic flow in heavy ion collisions. Recently it was shown that the expected factorization of two-particle results into a product of the constituent single-particle anisotropies is broken. The new information provided by these modes may shed light on themore » breakdown of flow factorization in heavy ion collisions. The first two modes (“leading” and “subleading”) of two-particle correlations are presented for elliptical and triangular anisotropies in PbPb and pPb collisions as a function of p T over a wide range of event activity. The leading mode is found to be essentially equivalent to the anisotropy harmonic previously extracted from two-particle correlation methods. The subleading mode represents a new experimental observable and is shown to account for a large fraction of the factorization breaking recently observed at high transverse momentum. The principle-component analysis technique was also applied to multiplicity fluctuations. These also show a subleading mode. As a result, the connection of these new results to previous studies of factorization is discussed.« less

Three component laser anemometer measurements in an annular cascade of core turbine vanes with contoured end wall

NASA Technical Reports Server (NTRS)

Goldman, Louis J.; Seasholtz, Richard G.

1988-01-01

The three mean velocity components were measured in a full-scale annular turbine stator cascade with contoured hub end wall using a newly developed laser anemometer system. The anemometer consists of a standard fringe configuration using fluorescent seed particles to measure the axial and tangential components. The radial component is measured with a scanning confocal Fabry-Perot interferometer. These two configurations are combined in a single optical system that can operate simultaneously in a backscatter mode through a single optical access port. Experimental measurements were obtained both within and downstream of the stator vane row and compared with calculations from a three-dimensional inviscid computer program. In addition, detailed calibration procedures are described that were used, prior to the experiment, to accurately determine the laser beam probe volume location relative to the cascade hardware.

Two-component relativistic coupled-cluster methods using mean-field spin-orbit integrals

NASA Astrophysics Data System (ADS)

Liu, Junzi; Shen, Yue; Asthana, Ayush; Cheng, Lan

2018-01-01

A novel implementation of the two-component spin-orbit (SO) coupled-cluster singles and doubles (CCSD) method and the CCSD augmented with the perturbative inclusion of triple excitations [CCSD(T)] method using mean-field SO integrals is reported. The new formulation of SO-CCSD(T) features an atomic-orbital-based algorithm for the particle-particle ladder term in the CCSD equation, which not only removes the computational bottleneck associated with the large molecular-orbital integral file but also accelerates the evaluation of the particle-particle ladder term by around a factor of 4 by taking advantage of the spin-free nature of the instantaneous electron-electron Coulomb interaction. Benchmark calculations of the SO splittings for the thallium atom and a set of diatomic 2Π radicals as well as of the bond lengths and harmonic frequencies for a set of closed-shell diatomic molecules are presented. The basis-set and core-correlation effects in the calculations of these properties have been carefully analyzed.

Numerical simulation of advection fog formation on multi-disperse aerosols due to combustion-related pollutants

NASA Technical Reports Server (NTRS)

Hung, R. J.; Liaw, G. S.

1980-01-01

The effects of multi-disperse distribution of the aerosol population are presented. Single component and multi-component aerosol species on the condensation/nucleation processes which affect the reduction in visibility are described. The aerosol population with a high particle concentration provided more favorable conditions for the formation of a denser fog than the aerosol population with a greater particle size distribution when the value of the mass concentration of the aerosols was kept constant. The results were used as numerical predictions of fog formation. Two dimensional observations in horizontal and vertical coordinates, together with time-dependent measurements were needed as initial values for the following physical parameters: (1)wind profiles; (2) temperature profiles; (3) humidity profiles; (4) mass concentration of aerosol particles; (5) particle size distribution of aerosols; and (6) chemical composition of aerosols. Formation and dissipation of advection fog, thus, can be forecasted numerically by introducing initial values obtained from the observations.

Biochemical studies of rat lung following exposure to potassium dichromate or chromium-rich welding fume particles.

PubMed

White, L R; Hunt, J; Richards, R J; Eik-Nes, K B

1982-04-01

Rats were examined for biochemical changes at the lung surface and in lung tissue 1, 4, and 13 weeks after a single instillation of the soluble of insoluble fraction of stainless steel welding particles, or potassium dichromate containing concentrations of hexavalent chromium (CrVI) equivalent to those found in the welding particles. Most of the toxicity of the welding particles 1 week after instillation could be related to the content of soluble CrVI, though the insoluble particles also produced changes at the alveolar surface. The regression of inflammatory changes 4 and 13 weeks after instillation was probably due to the removal of soluble components such as CrVI from the lung.

Dark-matter particles without weak-scale masses or weak interactions.

PubMed

Feng, Jonathan L; Kumar, Jason

2008-12-05

We propose that dark matter is composed of particles that naturally have the correct thermal relic density, but have neither weak-scale masses nor weak interactions. These models emerge naturally from gauge-mediated supersymmetry breaking, where they elegantly solve the dark-matter problem. The framework accommodates single or multiple component dark matter, dark-matter masses from 10 MeV to 10 TeV, and interaction strengths from gravitational to strong. These candidates enhance many direct and indirect signals relative to weakly interacting massive particles and have qualitatively new implications for dark-matter searches and cosmological implications for colliders.

Nonisothermal Brownian motion: Thermophoresis as the macroscopic manifestation of thermally biased molecular motion.

PubMed

Brenner, Howard

2005-12-01

A quiescent single-component gravity-free gas subject to a small steady uniform temperature gradient T, despite being at rest, is shown to experience a drift velocity UD=-D* gradient ln T, where D* is the gas's nonisothermal self-diffusion coefficient. D* is identified as being the gas's thermometric diffusivity alpha. The latter differs from the gas's isothermal isotopic self-diffusion coefficient D, albeit only slightly. Two independent derivations are given of this drift velocity formula, one kinematical and the other dynamical, both derivations being strictly macroscopic in nature. Within modest experimental and theoretical uncertainties, this virtual drift velocity UD=-alpha gradient ln T is shown to be constitutively and phenomenologically indistinguishable from the well-known experimental and theoretical formulas for the thermophoretic velocity U of a macroscopic (i.e., non-Brownian) non-heat-conducting particle moving under the influence of a uniform temperature gradient through an otherwise quiescent single-component rarefied gas continuum at small Knudsen numbers. Coupled with the size independence of the particle's thermophoretic velocity, the empirically observed equality, U=UD, leads naturally to the hypothesis that these two velocities, the former real and the latter virtual, are, in fact, simply manifestations of the same underlying molecular phenomenon, namely the gas's Brownian movement, albeit biased by the temperature gradient. This purely hydrodynamic continuum-mechanical equality is confirmed by theoretical calculations effected at the kinetic-molecular level on the basis of an existing solution of the Boltzmann equation for a quasi-Lorentzian gas, modulo small uncertainties pertaining to the choice of collision model. Explicitly, this asymptotically valid molecular model allows the virtual drift velocity UD of the light gas and the thermophoretic velocity U of the massive, effectively non-Brownian, particle, now regarded as the tracer particle of the light gas's drift velocity, to each be identified with the Chapman-Enskog "thermal diffusion velocity" of the quasi-Lorentzian gas, here designated by the symbol UM/M, as calculated by de la Mora and Mercer. It is further pointed out that, modulo the collective uncertainties cited above, the common velocities UD,U, and UM/M are identical to the single-component gas's diffuse volume current jv, the latter representing yet another, independent, strictly continuum-mechanical concept. Finally, comments are offered on the extension of the single-component drift velocity notion to liquids, and its application towards rationalizing Soret thermal-diffusion separation phenomena in quasi-Lorentzian liquid-phase binary mixtures composed of disparately sized solute and solvent molecules, with the massive Brownian solute molecules (e.g., colloidal particles) present in disproportionately small amounts relative to that of the solvent.

Femtosecond X-ray diffraction from an aerosolized beam of protein nanocrystals

DOE PAGES

Awel, Salah; Kirian, Richard A.; Wiedorn, Max O.; ...

2018-02-01

High-resolution Bragg diffraction from aerosolized single granulovirus nanocrystals using an X-ray free-electron laser is demonstrated. The outer dimensions of the in-vacuum aerosol injector components are identical to conventional liquid-microjet nozzles used in serial diffraction experiments, which allows the injector to be utilized with standard mountings. As compared with liquid-jet injection, the X-ray scattering background is reduced by several orders of magnitude by the use of helium carrier gas rather than liquid. Such reduction is required for diffraction measurements of small macromolecular nanocrystals and single particles. High particle speeds are achieved, making the approach suitable for use at upcoming high-repetition-rate facilities.

Confocal Raman microscopy for monitoring chemical reactions on single optically trapped, solid-phase support particles.

PubMed

Houlne, Michael P; Sjostrom, Christopher M; Uibel, Rory H; Kleimeyer, James A; Harris, Joel M

2002-09-01

Optical trapping of small structures is a powerful tool for the manipulation and investigation of colloidal and particulate materials. The tight focus excitation requirements of optical trapping are well suited to confocal Raman microscopy. In this work, an inverted confocal Raman microscope is developed for studies of chemical reactions on single, optically trapped particles and applied to reactions used in solid-phase peptide synthesis. Optical trapping and levitation allow a particle to be moved away from the coverslip and into solution, avoiding fluorescence interference from the coverslip. More importantly, diffusion of reagents into the particle is not inhibited by a surface, so that reaction conditions mimic those of particles dispersed in solution. Optical trapping and levitation also maintain optical alignment, since the particle is centered laterally along the optical axis and within the focal plane of the objective, where both optical forces and light collection are maximized. Hour-long observations of chemical reactions on individual, trapped silica particles are reported. Using two-dimensional least-squares analysis methods, the Raman spectra collected during the course of a reaction can be resolved into component contributions. The resolved spectra of the time-varying species can be observed, as they bind to or cleave from the particle surface.

Single agglutinates: A comparative study of compositions of agglutinitic glass, whole-grain, bulk soil, and FMR

NASA Technical Reports Server (NTRS)

Basu, A.; Robinson, R.; Mckay, D. S.; Blanchard, D. P.; Morris, R. V.; Wentworth, Susan J.

1994-01-01

Previous workers on single agglutinates have variously interpreted the composition of agglutinitic glass to represent impact melts of (1) bulk soil, (2) mixed components in finer sizes, and (3) microtargets. Separately, Papike has argued in favor of fusion of the finest fraction of bulk soils. Thirty-four single agglutinates were hand-picked from the mature Apollo 16 soil 61181 (I(sub s)/FeO = 82) and the FMR and chemical composition (INAA for Fe, Sc, Sm, Co, Ni, and Cr) of each agglutinate particle were measured. Thirteen of these single agglutinates were selected for electron beam microanalysis and imaging. Less than 1 micron spots were analyzed (for Na, Mg, Al, Si, P, S, K, Ca, Ti, Cr, Mn, Fe, Ni, and Ba) on pure glassy areas (approximately ten in each particle) selected on the basis of optical and BSE images (avoiding all clasts and inclusions) with an electron microprobe to obtain average glass compositions of each single agglutinate.

Phoresis in fluids.

PubMed

Brenner, Howard

2011-12-01

This paper presents a unified theory of phoretic phenomena in single-component fluids. Simple formulas are given for the phoretic velocities of small inert force-free non-Brownian particles migrating through otherwise quiescent single-component gases and liquids and animated by a gradient in the fluid's temperature (thermophoresis), pressure (barophoresis), density (pycnophoresis), or any combination thereof. The ansatz builds upon a recent paper [Phys. Rev. E 84, 046309 (2011)] concerned with slip of the fluid's mass velocity at solid surfaces--that is, with phenomena arising from violations of the classical no-slip fluid-mechanical boundary condition. Experimental and other data are cited in support of the phoretic model developed herein.

Decorrelation correction for nanoparticle tracking analysis of dilute polydisperse suspensions in bulk flow

NASA Astrophysics Data System (ADS)

Hartman, John; Kirby, Brian

2017-03-01

Nanoparticle tracking analysis, a multiprobe single particle tracking technique, is a widely used method to quickly determine the concentration and size distribution of colloidal particle suspensions. Many popular tools remove non-Brownian components of particle motion by subtracting the ensemble-average displacement at each time step, which is termed dedrifting. Though critical for accurate size measurements, dedrifting is shown here to introduce significant biasing error and can fundamentally limit the dynamic range of particle size that can be measured for dilute heterogeneous suspensions such as biological extracellular vesicles. We report a more accurate estimate of particle mean-square displacement, which we call decorrelation analysis, that accounts for correlations between individual and ensemble particle motion, which are spuriously introduced by dedrifting. Particle tracking simulation and experimental results show that this approach more accurately determines particle diameters for low-concentration polydisperse suspensions when compared with standard dedrifting techniques.

Chemical characterization of freshly emitted particulate matter from aircraft exhaust using single particle mass spectrometry

NASA Astrophysics Data System (ADS)

Abegglen, Manuel; Brem, B. T.; Ellenrieder, M.; Durdina, L.; Rindlisbacher, T.; Wang, J.; Lohmann, U.; Sierau, B.

2016-06-01

Non-volatile aircraft engine emissions are an important anthropogenic source of soot particles in the upper troposphere and in the vicinity of airports. They influence climate and contribute to global warming. In addition, they impact air quality and thus human health and the environment. The chemical composition of non-volatile particulate matter emission from aircraft engines was investigated using single particle time-of-flight mass spectrometry. The exhaust from three different aircraft engines was sampled and analyzed. The soot particulate matter was sampled directly behind the turbine in a test cell at Zurich Airport. Single particle analyses will focus on metallic compounds. The particles analyzed herein represent a subset of the emissions composed of the largest particles with a mobility diameter >100 nm due to instrumental restrictions. A vast majority of the analyzed particles was shown to contain elemental carbon, and depending on the engine and the applied thrust the elemental carbon to total carbon ratio ranged from 83% to 99%. The detected metallic compounds were all internally mixed with the soot particles. The most abundant metals in the exhaust were Cr, Fe, Mo, Na, Ca and Al; V, Ba, Co, Cu, Ni, Pb, Mg, Mn, Si, Ti and Zr were also detected. We further investigated potential sources of the ATOFMS-detected metallic compounds using Inductively Coupled Plasma Mass Spectrometry. The potential sources considered were kerosene, engine lubrication oil and abrasion from engine wearing components. An unambiguous source apportionment was not possible because most metallic compounds were detected in several of the analyzed sources.

Microwave Dielectric Constant Dependence on Soil Tension.

DTIC Science & Technology

1983-10-01

water to be only a single monolayer thick .1 (OA) with Ice-like dielectric properties EWS = (3.15, JO). The first approach apportions the soil solution Into...mixing model that accounts explicitly for the presence of a hydrationU layer of bound water adjacent to hydrophilic soil particle surfaces. The soil ... solution is differentiated Into (1) a bound, ice-like component and (2) a bulk solution component, by a physical soil model dependent upon either soil

Stability of the wobbling motion in the triaxially deformed odd-A nucleus

NASA Astrophysics Data System (ADS)

Tanabe, Kosai; Sugawara-Tanabe, Kazuko

2017-12-01

In order to analyze the content of the exact solutions for particle-rotor models with both the rigid and the hydrodynamical moments of inertia (MoI), as a theoretical probe we apply the Holstein-Primakoff (HP) boson expansion method to the total angular momentum I and the single-particle angular momentum j. We study the competition between Coriolis force and the single-particle potential by employing the different choices of the diagonal HP boson representations for the components of I and j along a common coordinate axis, and along perpendicular axes. We do not find any wobbling level sequence associated with the rotation around the principal axis with the medium MoI. The staggering in the alignments of I about the axis with the medium MoI is found in the limited range of I, while the vector R(=I-j) is confined about the axis with the largest MoI.

Pneumoconiotic effects of welding-fume particles from mild and stainless steel deposited in the lung of the rat.

PubMed

Hicks, R; Lam, H F; Al-Shamma, K J; Hewitt, P J

1984-03-01

Rats were exposed to single periods of inhalation of fumes generated by arc welding. Two processes were compared: either manual metal arc (MMA) using flux-coated mild steel (MS) electrodes or metal inert-gas (MIG) welding with stainless steel (SS). Widespread but small deposits of fume particles were cleared effectively from alveoli and airways. Peribronchial and subpleural aggregates of particle-laden macrophages remained. More massive and persistent lung-burdens were established by intratracheal administration of suspensions of fume-particles (10 mg and 50 mg, single doses). Initial pneumonitis was attributed to irritant gases or soluble toxic components of particles. MIG-SS particle deposits were more persistent and lesions more severe, inhibition of phagocytosis or clearance and damage to epithelial cells being associated with possible toxic effects in macrophages. Both types of particle caused alveolar epithelial thickening, with proliferation of granular pneumocytes and exudation of lamellar material. Foam cells appeared in alveoli. Long-term effects (80-300 days) involved formation of nodular aggregates of particle-laden macrophages. Giant cells were formed. Nodules containing MIG-SS material were irregular and surrounded by collapsed and thickened epithelium. Soluble chromium or nickel constituents are cited as probable active agents producing effects resembling those of cytotoxic non-fibrogenic dusts, e.g., soluble silicas . MMA-MS particles produced low-grade fibrotic ( collagenised ) changes.

Analysis of particle in liquid using excitation-fluorescence spectral flow cytometer

NASA Astrophysics Data System (ADS)

Takenaka, Kei; Togashi, Shigenori

2018-01-01

We have developed a new flow cytometer that can measure the excitation-fluorescence spectra of a single particle. This system consists of a solution-transmitting unit and an optical unit. The solution-transmitting unit allows a sample containing particles to flow through the center of a flow cell by hydrodynamic focusing. The optical unit irradiates particles with dispersed white light (wavelength band: 400-650 nm) along the flow direction and measures their fluorescence spectra (wavelength band: 400-700 nm) using a spectroscopic photodetector array. The fluorescence spectrum of a particle changes with the shift of the wavelength of the excitation light. Using this system, the excitation-fluorescence spectra of a fluorescent particle were measured. Additionally, a homogenized tomato suspension and a homogenized spinach suspension were measured using the system. Measurement results show that it is possible to determine the components of vegetables by comparing measured fluorescence spectra of particles in a vegetable suspension.

A determination of relativistic shock jump conditions using Monte Carlo techniques

NASA Technical Reports Server (NTRS)

Ellison, Donald C.; Reynolds, Stephen P.

1991-01-01

Monte Carlo techniques are used, assuming isotropic elastic scattering of all particles, to calculate jump conditions in parallel relativistic collisionless shocks in the absence of Fermi acceleration. The shock velocity and compression ratios are shown for arbitrary flow velocities and for any upstream temperature. Both single-component electron-positron plasma and two-component proton-electron plasmas are considered. It is shown that protons and electrons must share energy, directly or through the mediation of plasma waves, in order to satisfy the basic conservation conditions, and the electron and proton temperatures are determined for a particular microscopic, kinetic-theory model, namely, that protons always scatter elastically. The results are directly applicable to shocks in which waves of scattering superthermal particles are absent.

Hygroscopicity and volatility of semi-volatile organic components in optical levitated single organic/inorganic aqueous aerosol droplet

NASA Astrophysics Data System (ADS)

Cai, C.; Zhao, C.

2017-12-01

Quantifying the gas/particle partitioning of organic compounds is of great significance to the understanding of atmospheric aerosol indirect effect. Accurate determination of the hygroscopicities and vapor pressures of semi-volatile organic compounds (SVOC) is of crucial importance in studying their partitioning behavior into atmospheric aerosol, as current published vapor pressures results of compounds of interest (usually with vapor pressures smaller than 0.01 Pa) vary by several orders of magnitude. On the other hand, influences on SVOCs evaporation from participation of inorganic species remains ambiguous. In this study we present quantitative investigation of hygroscopicities and volatilities of single aerosol droplets in an aerosol optical tweezers. The trapped droplet (3-7 µm radii) in the aerosol optical tweezers acts as a micro cavity, which stimulates the cavity enhanced Raman spectroscopy (CERS) signal. Size and composition of the particle are calculated from Mie fit to the positions of the "whispering gallery modes" in the CERS fingerprint. Hygroscopic behaviors and SVOC pure component vapor pressure can then be extracted from the correlation between the changing droplet radius and solute concentration (derived from experimentally determined RI real part). We will further present the influences between mass transfer on the gas-particle interface and within the droplet.

Quantum self-organization and nuclear collectivities

NASA Astrophysics Data System (ADS)

Otsuka, T.; Tsunoda, Y.; Togashi, T.; Shimizu, N.; Abe, T.

2018-02-01

The quantum self-organization is introduced as one of the major underlying mechanisms of the quantum many-body systems. In the case of atomic nuclei as an example, two types of the motion of nucleons, single-particle states and collective modes, dominate the structure of the nucleus. The outcome of the collective mode is determined basically by the balance between the effect of the mode-driving force (e.g., quadrupole force for the ellipsoidal deformation) and the resistance power against it. The single-particle energies are one of the sources to produce such resistance power: a coherent collective motion is more hindered by larger gaps between relevant single particle states. Thus, the single-particle state and the collective mode are “enemies” each other. However, the nuclear forces are demonstrated to be rich enough so as to enhance relevant collective mode by reducing the resistance power by changing singleparticle energies for each eigenstate through monopole interactions. This will be verified with the concrete example taken from Zr isotopes. Thus, when the quantum self-organization occurs, single-particle energies can be self-organized, being enhanced by (i) two quantum liquids, e.g., protons and neutrons, (ii) two major force components, e.g., quadrupole interaction (to drive collective mode) and monopole interaction (to control resistance). In other words, atomic nuclei are not necessarily like simple rigid vases containing almost free nucleons, in contrast to the naïve Fermi liquid picture. Type II shell evolution is considered to be a simple visible case involving excitations across a (sub)magic gap. The quantum self-organization becomes more important in heavier nuclei where the number of active orbits and the number of active nucleons are larger. The quantum self-organization is a general phenomenon, and is expected to be found in other quantum systems.

Mechanism for the formation and microphysical characteristics of submicron aerosol during heavy haze pollution episode in the Yangtze River Delta, China.

PubMed

Wang, Honglei; An, Junlin; Shen, Lijuan; Zhu, Bin; Pan, Chen; Liu, Zirui; Liu, Xiaohui; Duan, Qing; Liu, Xuan; Wang, Yuesi

2014-08-15

In this paper we investigate a severe pollution episode that occurred in the Yangtze River Delta (YRD) region in January 2013. The episode was caused by the combination of anthropogenic emissions and unusual atmospheric circulation, the depression of strong cold air activities and the very unfavorable dispersion. The episode contained three haze events (haze1: Jan. 4-9, haze2: Jan. 10-13, and haze3: Jan. 14-16). In Nanjing, aerosol size distributions from 10nm to 10 μm and chemical components of single particles from 0.2 to 2 μm were measured with a Wide Range Particle Spectrometer (WPS) and a Single Particle Aerosol Mass Spectrometer (SPAMS), respectively. The results indicate that the mean PM2.5 concentrations in the YRD region were greater than 110 μg·m(-3). The highest PM2.5 concentration of 175.6 μg·m(-3) occurred in Nanjing; the other cities had values in the range of 110.8-147.3 μg·m(-3). The average PM2.5 concentrations were 58.3, 122.7, 145.4 and 154.7 μg·m(-3) on clean and haze1, haze2 and haze3 days, respectively. The highest PM2.5 values of 416.5, 415.5 and 300.5 μg·m(-3) in Nanjing occurred during the three haze events. The spectra of the aerosol number concentrations had unimodal distributions on clean and haze days. The maximum surface area peaks were located at 0.5-0.7 μm and had values of 419, 1397, 1309 and 1378 μm(2)·cm(-3)·nm(-1) on clean and haze1, haze2 and haze3 days, respectively. The number concentrations of biomass/biofuel burning-containing particles (biomass), organic carbon-containing particles (OC), elemental carbon-containing particles (EC), nitrate-containing particles (nitrate) and sulfate-containing particles (sulfate) increased significantly during the haze events. The chemical components of the aerosols during the haze1 and haze2 events were similar to those on clean days, and variations were caused by local particle accumulations under poor diffusion conditions. The high EC particle concentration of 24.76% during the haze3 event was impacted by the pollutants transported from surrounding cities. In addition, the different chemical components showed distinct size distributions. Copyright © 2014 Elsevier B.V. All rights reserved.

NMRI Measurements of Flow of Granular Mixtures

NASA Technical Reports Server (NTRS)

Nakagawa, Masami; Waggoner, R. Allen; Fukushima, Eiichi

1996-01-01

We investigate complex 3D behavior of granular mixtures in shaking and shearing devices. NMRI can non-invasively measure concentration, velocity, and velocity fluctuations of flows of suitable particles. We investigate origins of wall-shear induced convection flow of single component particles by measuring the flow and fluctuating motion of particles near rough boundaries. We also investigate if a mixture of different size particles segregate into their own species under the influence of external shaking and shearing disturbances. These non-invasive measurements will reveal true nature of convecting flow properties and wall disturbance. For experiments in a reduced gravity environment, we will design a light weight NMR imager. The proof of principle development will prepare for the construction of a complete spaceborne system to perform experiments in space.

Fabrication of chitosan single-component microcapsules with a micrometer-thick and layered wall structure by stepwise core-mediated precipitation.

PubMed

Han, Yuanyuan; Tong, Weijun; Zhang, Yuying; Gao, Changyou

2012-02-27

Incubation of CaCO(3) microparticles in chitosan (CS) solution at pH 5.2 and following with ethylenediaminetetraacetic acid disodium salt (EDTA) treatment resulted in CS single-component microcapsules with an ultra-thick wall structure. Repeating the incubation caused stepwise increase of wall thickness and finally resulted in CS microcapsules with a layered structure. This unique method is mediated by precipitation of CS on the CaCO(3) particles as a result of pH increase caused by the partial dissolution of CaCO(3) . The obtained CS capsules are stable at neutral pH. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Applications of seismic spatial wavefield gradient and rotation data in exploration seismology

NASA Astrophysics Data System (ADS)

Schmelzbach, C.; Van Renterghem, C.; Sollberger, D.; Häusler, M.; Robertsson, J. O. A.

2017-12-01

Seismic spatial wavefield gradient and rotation data have the potential to open up new ways to address long-standing problems in land-seismic exploration such as identifying and separating P-, S-, and surface waves. Gradient-based acquisition and processing techniques could enable replacing large arrays of densely spaced receivers by sparse spatially-compact receiver layouts or even one single multicomponent station with dedicated instruments (e.g., rotational seismometers). Such approaches to maximize the information content of single-station recordings are also of significant interest for seismic measurements at sites with limited access such as boreholes, the sea bottom, and extraterrestrial seismology. Arrays of conventional three-component (3C) geophones enable measuring not only the particle velocity in three dimensions but also estimating their spatial gradients. Because the free-surface condition allows to express vertical derivatives in terms of horizontal derivatives, the full gradient tensor and, hence, curl and divergence of the wavefield can be computed. In total, three particle velocity components, three rotational components, and divergence, result seven-component (7C) seismic data. Combined particle velocity and gradient data can be used to isolate the incident P- or S-waves at the land surface or the sea bottom using filtering techniques based on the elastodynamic representation theorem. Alternatively, as only S-waves exhibit rotational motion, rotational measurements can directly be used to identify S-waves. We discuss the derivations of the gradient-based filters as well as their application to synthetic and field data, demonstrating that rotational data can be of particular interest to S-wave reflection and P-to-S-wave conversion imaging. The concept of array-derived gradient estimation can be extended to source arrays as well. Therefore, source arrays allow us to emulate rotational (curl) and dilatational (divergence) sources. Combined with 7C recordings, a total of 49 components of the seismic wavefield can be excited and recorded. Such data potentially allow to further improve wavefield separation and may find application in directional imaging and coherent noise suppression.

Scavenging of pollutant acid substances by Asian mineral dust particles - article no. L07816

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsumoto, J.; Takahashi, K.; Matsumi, Y.

2006-04-13

Uptakes of sulfate and nitrate onto Asian dust particles during transport from the Asian continent to the Pacific Ocean were analyzed by using a single-particle time-of-flight mass spectrometer. Observation was conducted at Tsukuba in Japan in the springtime of 2004. Sulfate-rich dust particles made their largest contribution during the 'dust event' in the middle of April 2004. As a result of detailed analysis including backward trajectory calculations, it was confirmed that sulfate components originating from coal combustion in the continent were internally mixed with dust particles. Even in the downstream of the outflow far from the continental coastline, significant contributionmore » of Asian dust to sulfate was observed. Asian dust plays critical roles as the carrier of sulfate over the Pacific Ocean.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Chao

Sparx, a new environment for Cryo-EM image processing; Cryo-EM, Single particle reconstruction, principal component analysis; Hardware Req.: PC, MAC, Supercomputer, Mainframe, Multiplatform, Workstation. Software Req.: operating system is Unix; Compiler C++; type of files: source code, object library, executable modules, compilation instructions; sample problem input data. Location/transmission: http://sparx-em.org; User manual & paper: http://sparx-em.org;

Uncovering homo-and hetero-interactions on the cell membrane using single particle tracking approaches

NASA Astrophysics Data System (ADS)

Torreno-Pina, Juan A.; Manzo, Carlo; Garcia-Parajo, Maria F.

2016-03-01

The plasma membrane of eukaryotic cells is responsible for a myriad of functions that regulate cell physiology and plays a crucial role in a multitude of processes that include adhesion, migration, signaling recognition and cell-cell communication. This is accomplished by specific interactions between different membrane components such as lipids and proteins on the lipid bilayer but also through interactions with the underlying cortical actin cytoskeleton on the intracellular side and the glycocalyx matrix in close proximity to the extracellular side. Advanced biophysical techniques, including single particle tracking (SPT) have revealed that the lateral diffusion of molecular components on the plasma membrane represents a landmark manifestation of such interactions. Indeed, by studying changes in the diffusivity of individual membrane molecules, including sub-diffusion, confined diffusion and/or transient arrest of molecules in membrane compartments, it has been possible to gain insight on the nature of molecular interactions and to infer on its functional role for cell response. In this review, we will revise some exciting results where SPT has been crucial to reveal homo- and hetero-interactions on the cell membrane.

BCS Theory of Time-Reversal-Symmetric Hofstadter-Hubbard Model

NASA Astrophysics Data System (ADS)

Umucalılar, R. O.; Iskin, M.

2017-08-01

The competition between the length scales associated with the periodicity of a lattice potential and the cyclotron radius of a uniform magnetic field is known to have dramatic effects on the single-particle properties of a quantum particle, e.g., the fractal spectrum is known as the Hofstadter butterfly. Having this intricate competition in mind, we consider a two-component Fermi gas on a square optical lattice with opposite synthetic magnetic fields for the components, and study its effects on the many-body BCS-pairing phenomenon. By a careful addressing of the distinct superfluid transitions from the semimetal, quantum spin-Hall insulator, or normal phases, we explore the low-temperature phase diagrams of the model, displaying lobe structures that are reminiscent of the well-known Mott-insulator transitions of the Bose-Hubbard model.

Permanent magnet system to guide superparamagnetic particles

NASA Astrophysics Data System (ADS)

Baun, Olga; Blümler, Peter

2017-10-01

A new concept of using permanent magnet systems for guiding superparamagnetic nano-particles on arbitrary trajectories over a large volume is proposed. The basic idea is to use one magnet system which provides a strong, homogeneous, dipolar magnetic field to magnetize and orient the particles, and a second constantly graded, quadrupolar field, superimposed on the first, to generate a force on the oriented particles. In this configuration the motion of the particles is driven predominantly by the component of the gradient field which is parallel to the direction of the homogeneous field. As a result, particles are guided with constant force and in a single direction over the entire volume. The direction is simply adjusted by varying the angle between quadrupole and dipole. Since a single gradient is impossible due to Gauß' law, the other gradient component of the quadrupole determines the angular deviation of the force. However, the latter can be neglected if the homogeneous field is stronger than the local contribution of the quadrupole field. A possible realization of this idea is a coaxial arrangement of two Halbach cylinders. A dipole to evenly magnetize and orient the particles, and a quadrupole to generate the force. The local force was calculated analytically for this particular geometry and the directional limits were analyzed and discussed. A simple prototype was constructed to demonstrate the principle in two dimensions on several nano-particles of different size, which were moved along a rough square by manual adjustment of the force angle. The observed velocities of superparamagnetic particles in this prototype were always several orders of magnitude higher than the theoretically expected value. This discrepancy is attributed to the observed formation of long particle chains as a result of their polarization by the homogeneous field. The magnetic moment of such a chain is then the combination of that of its constituents, while its hydrodynamic radius stays low. A complete system will consist of another quadrupole (third cylinder) to additionally enable scaling of the gradient/force strength by another rotation. In this configuration the device could then also be used as a simple MRI machine to image the particles between movement intervals. Finally, a concept is proposed by which superparamagnetic particles can be guided in three-dimensional space.

Relativistic plasma control for single attosecond x-ray burst generation

NASA Astrophysics Data System (ADS)

Baeva, T.; Gordienko, S.; Pukhov, A.

2006-12-01

We show that managing time-dependent polarization of the relativistically intense laser pulse incident on a plasma surface allows us to gate a single (sub)attosecond x-ray burst even when a multicycle driver is used. The single x-ray burst is emitted when the tangential component of the vector potential at the plasma surface vanishes. This relativistic plasma control is based on the theory of relativistic spikes [T. Baeva, S. Gordienko, and A. Pukhov, Phys. Rev. E 74, 046404 (2006)]. The relativistic plasma control is demonstrated here numerically by particle-in-cell simulations.

Approaches to Quality Risk Management When Using Single-Use Systems in the Manufacture of Biologics.

PubMed

Ishii-Watabe, Akiko; Hirose, Akihiko; Katori, Noriko; Hashii, Norikata; Arai, Susumu; Awatsu, Hirotoshi; Eiza, Akira; Hara, Yoshiaki; Hattori, Hideshi; Inoue, Tomomi; Isono, Tetsuya; Iwakura, Masahiro; Kajihara, Daisuke; Kasahara, Nobuo; Matsuda, Hiroyuki; Murakami, Sei; Nakagawa, Taishiro; Okumura, Takehiro; Omasa, Takeshi; Takuma, Shinya; Terashima, Iyo; Tsukahara, Masayoshi; Tsutsui, Maiko; Yano, Takahiro; Kawasaki, Nana

2015-10-01

Biologics manufacturing technology has made great progress in the last decade. One of the most promising new technologies is the single-use system, which has improved the efficiency of biologics manufacturing processes. To ensure safety of biologics when employing such single-use systems in the manufacturing process, various issues need to be considered including possible extractables/leachables and particles arising from the components used in single-use systems. Japanese pharmaceutical manufacturers, together with single-use suppliers, members of the academia and regulatory authorities have discussed the risks of using single-use systems and established control strategies for the quality assurance of biologics. In this study, we describe approaches for quality risk management when employing single-use systems in the manufacturing of biologics. We consider the potential impact of impurities related to single-use components on drug safety and the potential impact of the single-use system on other critical quality attributes as well as the stable supply of biologics. We also suggest a risk-mitigating strategy combining multiple control methods which includes the selection of appropriate single-use components, their inspections upon receipt and before releasing for use and qualification of single-use systems. Communication between suppliers of single-use systems and the users, as well as change controls in the facilities both of suppliers and users, are also important in risk-mitigating strategies. Implementing these control strategies can mitigate the risks attributed to the use of single-use systems. This study will be useful in promoting the development of biologics as well as in ensuring their safety, quality and stable supply.

Characterization of a catalyst-based conversion technique to measure total particulate nitrogen and organic carbon and comparison to a particle mass measurement instrument

NASA Astrophysics Data System (ADS)

Stockwell, Chelsea E.; Kupc, Agnieszka; Witkowski, Bartłomiej; Talukdar, Ranajit K.; Liu, Yong; Selimovic, Vanessa; Zarzana, Kyle J.; Sekimoto, Kanako; Warneke, Carsten; Washenfelder, Rebecca A.; Yokelson, Robert J.; Middlebrook, Ann M.; Roberts, James M.

2018-05-01

The chemical composition of aerosol particles is a key aspect in determining their impact on the environment. For example, nitrogen-containing particles impact atmospheric chemistry, air quality, and ecological N deposition. Instruments that measure total reactive nitrogen (Nr = all nitrogen compounds except for N2 and N2O) focus on gas-phase nitrogen and very few studies directly discuss the instrument capacity to measure the mass of Nr-containing particles. Here, we investigate the mass quantification of particle-bound nitrogen using a custom Nr system that involves total conversion to nitric oxide (NO) across platinum and molybdenum catalysts followed by NO-O3 chemiluminescence detection. We evaluate the particle conversion of the Nr instrument by comparing to mass-derived concentrations of size-selected and counted ammonium sulfate ((NH4)2SO4), ammonium nitrate (NH4NO3), ammonium chloride (NH4Cl), sodium nitrate (NaNO3), and ammonium oxalate ((NH4)2C2O4) particles determined using instruments that measure particle number and size. These measurements demonstrate Nr-particle conversion across the Nr catalysts that is independent of particle size with 98 ± 10 % efficiency for 100-600 nm particle diameters. We also show efficient conversion of particle-phase organic carbon species to CO2 across the instrument's platinum catalyst followed by a nondispersive infrared (NDIR) CO2 detector. However, the application of this method to the atmosphere presents a challenge due to the small signal above background at high ambient levels of common gas-phase carbon compounds (e.g., CO2). We show the Nr system is an accurate particle mass measurement method and demonstrate its ability to calibrate particle mass measurement instrumentation using single-component, laboratory-generated, Nr-containing particles below 2.5 µm in size. In addition we show agreement with mass measurements of an independently calibrated online particle-into-liquid sampler directly coupled to the electrospray ionization source of a quadrupole mass spectrometer (PILS-ESI/MS) sampling in the negative-ion mode. We obtain excellent correlations (R2 = 0.99) of particle mass measured as Nr with PILS-ESI/MS measurements converted to the corresponding particle anion mass (e.g., nitrate, sulfate, and chloride). The Nr and PILS-ESI/MS are shown to agree to within ˜ 6 % for particle mass loadings of up to 120 µg m-3. Consideration of all the sources of error in the PILS-ESI/MS technique yields an overall uncertainty of ±20 % for these single-component particle streams. These results demonstrate the Nr system is a reliable direct particle mass measurement technique that differs from other particle instrument calibration techniques that rely on knowledge of particle size, shape, density, and refractive index.

Quantum turbulence in cold multicomponent matter

NASA Astrophysics Data System (ADS)

Pshenichnyuk, Ivan A.

2018-02-01

Quantum vortices are pivotal for understanding of phenomena in quantum hydrodynamics. Vortices were observed in different physical systems like trapped dilute Bose-Einstein condensates, liquid helium, exciton-polariton condensates and other types of systems. Foreign particles attached to the vortices often serve for a visualization of the vortex shape and kinematics in superfluid experiments. Fascinating discoveries were made in the field of cold quantum mixtures, where vortices created in one component may interact with the other component. This works raise the fundamental question of the interaction between quantum vortices and matter. The generalized nonlinear Schrodinger equation based formalism is applied here to model three different processes involving the interaction of quantum vortices with foreign particles: propagation of a fast classical particle in a superfluid under the influence of sound waves, scattering of a single fermion by a quantized vortex line and dynamics of vortex pairs doped with heavy bosonic matter. The obtained results allow to to clarify the details of recent experiments and acquire a better understanding of the multicomponent quantum turbulence.

Information storage and retrieval in a single levitating colloidal particle

NASA Astrophysics Data System (ADS)

Myers, Christopher J.; Celebrano, Michele; Krishnan, Madhavi

2015-10-01

The binary switch is a basic component of digital information. From phase-change alloys to nanomechanical beams, molecules and atoms, new strategies for controlled bistability hold great interest for emerging technologies. We present a generic methodology for precise and parallel spatiotemporal control of nanometre-scale matter in a fluid, and demonstrate the ability to attain digital functionalities such as switching, gating and data storage in a single colloid, with further implications for signal amplification and logic operations. This fluid-phase bit can be arrayed at high densities, manipulated by either electrical or optical fields, supports low-energy, high-speed operation and marks a first step toward ‘colloidal information’. The principle generalizes to any system where spatial perturbation of a particle elicits a differential response amenable to readout.

Information storage and retrieval in a single levitating colloidal particle.

PubMed

Myers, Christopher J; Celebrano, Michele; Krishnan, Madhavi

2015-10-01

The binary switch is a basic component of digital information. From phase-change alloys to nanomechanical beams, molecules and atoms, new strategies for controlled bistability hold great interest for emerging technologies. We present a generic methodology for precise and parallel spatiotemporal control of nanometre-scale matter in a fluid, and demonstrate the ability to attain digital functionalities such as switching, gating and data storage in a single colloid, with further implications for signal amplification and logic operations. This fluid-phase bit can be arrayed at high densities, manipulated by either electrical or optical fields, supports low-energy, high-speed operation and marks a first step toward 'colloidal information'. The principle generalizes to any system where spatial perturbation of a particle elicits a differential response amenable to readout.

Organic component vapor pressures and hygroscopicities of aqueous aerosol measured by optical tweezers.

PubMed

Cai, Chen; Stewart, David J; Reid, Jonathan P; Zhang, Yun-hong; Ohm, Peter; Dutcher, Cari S; Clegg, Simon L

2015-01-29

Measurements of the hygroscopic response of aerosol and the particle-to-gas partitioning of semivolatile organic compounds are crucial for providing more accurate descriptions of the compositional and size distributions of atmospheric aerosol. Concurrent measurements of particle size and composition (inferred from refractive index) are reported here using optical tweezers to isolate and probe individual aerosol droplets over extended timeframes. The measurements are shown to allow accurate retrievals of component vapor pressures and hygroscopic response through examining correlated variations in size and composition for binary droplets containing water and a single organic component. Measurements are reported for a homologous series of dicarboxylic acids, maleic acid, citric acid, glycerol, or 1,2,6-hexanetriol. An assessment of the inherent uncertainties in such measurements when measuring only particle size is provided to confirm the value of such a correlational approach. We also show that the method of molar refraction provides an accurate characterization of the compositional dependence of the refractive index of the solutions. In this method, the density of the pure liquid solute is the largest uncertainty and must be either known or inferred from subsaturated measurements with an error of <±2.5% to discriminate between different thermodynamic treatments.

Modification of Pawlow's thermodynamical model for the melting of small single-component particles

NASA Astrophysics Data System (ADS)

Barybin, Anatoly; Shapovalov, Victor

2011-02-01

A new approach to the melting of small particles is proposed to modify the known Pawlow's model by taking into account the transfer of material from solid spherical particles to liquid ones through a gas phase. Thermodynamical analysis gives rise to a differential equation for the melting point Tm involving such size-dependent and temperature-dependent parameters of a material as the surface tensions σs(l ), molar heat of fusion ΔHm and molar volumes vs(l ). Solution of this equation has shown that all the limiting cases for size-independent situations coincide with results known in the literature and our analysis of size-dependent situations gives results close to the experimental data previously obtained by other authors for some metallic particles.

Computational Prediction of Cryogenic Micro-nano Solid Nitrogen Particle Production Using Laval Nozzle for Physical Photo Resist Removal-cleaning Technology

NASA Astrophysics Data System (ADS)

Ishimoto, Jun; Abe, Haruto; Ochiai, Naoya

The fundamental characteristics of the cryogenic single-component micro-nano solid nitrogen (SN2) particle production using super adiabatic Laval nozzle and its application to the physical photo resist removal-cleaning technology are investigated by a new type of integrated measurement coupled computational technique. As a result of present computation, it is found that high-speed ultra-fine SN2 particles are continuously generated due to the freezing of liquid nitrogen (LN2) droplets induced by rapid adiabatic expansion of transonic subcooled two-phase nitrogen flow passing through the Laval nozzle. Furthermore, the effect of SN2 particle diameter, injection velocity, and attack angle to the wafer substrate on resist removal-cleaning performance is investigated in detail by integrated measurement coupled computational technique.

Characterisation of Black Carbon (BC) mixing state and flux in Beijing using single particle measurements.

NASA Astrophysics Data System (ADS)

Joshi, Rutambhara; Liu, Dantong; Allan, James; Coe, Hugh; Flynn, Michael; Broda, Kurtis; Olfert, Jason; Irwin, Martin; Sun, Yele; Fu, Pingqing; Wang, Junfeng; Ge, Xinlei; Langford, Ben; Nemitz, Eiko; Mullinger, Neil

2017-04-01

BC is generated by the incomplete combustion of carbonaceous fuels and it is an important component of fine PM2.5. In the atmosphere BC particles have a complex structure and its mixing state has crucial impact on optical properties. Quantifying the sources and emissions of black carbon in urban environments is important and presently uncertain, particularly in megacities undergoing rapid growth and change in emissions. During the winter of 2016 (10th Nov-10th Dec) the BC was characterised as part of a large joint UK-China field experiment in Beijing. This paper focuses on understanding the mixing state of BC as well as identification and quantification of BC sources. We used a combination of a Centrifugal Particle Mass Analyser (CPMA) and a Single Particle Soot Photometer (SP2) to uniquely quantify the morphology independent mass of single refractory BC particles and their coating content. The CPMA allows us to select pre-charged aerosol particles according to their mass to charge ratio and the SP2 provides information on the mass of refractory BC through a laser-induced incandescence method. Furthermore, another SP2 was used to measure the BC flux at 100m height using the Eddy Covariance method. We have successfully gathered 4 weeks of continuous measurements which include several severe pollution events in Beijing. Here we present preliminary results, characterising the distribution of coating mass on BC particles in Beijing and linking this to the main sources of BC in the city. We will provide initial estimates of the BC flux over a several kilometre footprint. Such analysis will provide important information for the further investigation of source distribution, emission, lifetime and optical properties of BC under complex environments in Beijing.

Calcination and solid state reaction of ceramic-forming components to provide single-phase superconducting materials having fine particle size

DOEpatents

Balachandran, Uthamalingam; Poeppel, Roger B.; Emerson, James E.; Johnson, Stanley A.

1992-01-01

An improved method for the preparation of single phase, fine grained ceramic materials from precursor powder mixtures where at least one of the components of the mixture is an alkali earth carbonate. The process consists of heating the precursor powders in a partial vacuum under flowing oxygen and under conditions where the partial pressure of CO.sub.2 evolved during the calcination is kept to a very low level relative to the oxygen. The process has been found particularly suitable for the preparation of high temperature copper oxide superconducting materials such as YBa.sub.2 Cu.sub.3 O.sub.x "123" and YBa.sub.2 Cu.sub.4 O.sub.8 "124".

Application of randomly oriented spheroids for retrieval of dust particle parameters from multiwavelength lidar measurements

NASA Astrophysics Data System (ADS)

Veselovskii, I.; Dubovik, O.; Kolgotin, A.; Lapyonok, T.; di Girolamo, P.; Summa, D.; Whiteman, D. N.; Mishchenko, M.; Tanré, D.

2010-11-01

Multiwavelength (MW) Raman lidars have demonstrated their potential to profile particle parameters; however, until now, the physical models used in retrieval algorithms for processing MW lidar data have been predominantly based on the Mie theory. This approach is applicable to the modeling of light scattering by spherically symmetric particles only and does not adequately reproduce the scattering by generally nonspherical desert dust particles. Here we present an algorithm based on a model of randomly oriented spheroids for the inversion of multiwavelength lidar data. The aerosols are modeled as a mixture of two aerosol components: one composed only of spherical and the second composed of nonspherical particles. The nonspherical component is an ensemble of randomly oriented spheroids with size-independent shape distribution. This approach has been integrated into an algorithm retrieving aerosol properties from the observations with a Raman lidar based on a tripled Nd:YAG laser. Such a lidar provides three backscattering coefficients, two extinction coefficients, and the particle depolarization ratio at a single or multiple wavelengths. Simulations were performed for a bimodal particle size distribution typical of desert dust particles. The uncertainty of the retrieved particle surface, volume concentration, and effective radius for 10% measurement errors is estimated to be below 30%. We show that if the effect of particle nonsphericity is not accounted for, the errors in the retrieved aerosol parameters increase notably. The algorithm was tested with experimental data from a Saharan dust outbreak episode, measured with the BASIL multiwavelength Raman lidar in August 2007. The vertical profiles of particle parameters as well as the particle size distributions at different heights were retrieved. It was shown that the algorithm developed provided substantially reasonable results consistent with the available independent information about the observed aerosol event.

The influence of the surface composition of mixed monolayer films on the evaporation coefficient of water.

PubMed

Miles, Rachael E H; Davies, James F; Reid, Jonathan P

2016-07-20

We explore the dependence of the evaporation coefficient of water from aqueous droplets on the composition of a surface film, considering in particular the influence of monolayer mixed component films on the evaporative mass flux. Measurements with binary component films formed from long chain alcohols, specifically tridecanol (C13H27OH) and pentadecanol (C15H31OH), and tetradecanol (C14H29OH) and hexadecanol (C16H33OH), show that the evaporation coefficient is dependent on the mole fractions of the two components forming the monolayer film. Immediately at the point of film formation and commensurate reduction in droplet evaporation rate, the evaporation coefficient is equal to a mole fraction weighted average of the evaporation coefficients through the equivalent single component films. As a droplet continues to diminish in surface area with continued loss of water, the more-soluble, shorter alkyl chain component preferentially partitions into the droplet bulk with the evaporation coefficient tending towards that through a single component film formed simply from the less-soluble, longer chain alcohol. We also show that the addition of a long chain alcohol to an aqueous-sucrose droplet can facilitate control over the degree of dehydration achieved during evaporation. After undergoing rapid gas-phase diffusion limited water evaporation, binary aqueous-sucrose droplets show a continued slow evaporative flux that is limited by slow diffusional mass transport within the particle bulk due to the rapidly increasing particle viscosity and strong concentration gradients that are established. The addition of a long chain alcohol to the droplet is shown to slow the initial rate of water loss, leading to a droplet composition that remains more homogeneous for a longer period of time. When the sucrose concentration has achieved a sufficiently high value, and the diffusion constant of water has decreased accordingly so that bulk phase diffusion arrest occurs in the monolayer coated particle, the droplet is found to have lost a greater proportion of its initial water content. A greater degree of slowing in the evaporative flux can be achieved by increasing the chain length of the surface active alcohol, leading to a greater degree of dehydration.

Fluorescent image tracking velocimeter

DOEpatents

Shaffer, Franklin D.

1994-01-01

A multiple-exposure fluorescent image tracking velocimeter (FITV) detects and measures the motion (trajectory, direction and velocity) of small particles close to light scattering surfaces. The small particles may follow the motion of a carrier medium such as a liquid, gas or multi-phase mixture, allowing the motion of the carrier medium to be observed, measured and recorded. The main components of the FITV include: (1) fluorescent particles; (2) a pulsed fluorescent excitation laser source; (3) an imaging camera; and (4) an image analyzer. FITV uses fluorescing particles excited by visible laser light to enhance particle image detectability near light scattering surfaces. The excitation laser light is filtered out before reaching the imaging camera allowing the fluoresced wavelengths emitted by the particles to be detected and recorded by the camera. FITV employs multiple exposures of a single camera image by pulsing the excitation laser light for producing a series of images of each particle along its trajectory. The time-lapsed image may be used to determine trajectory and velocity and the exposures may be coded to derive directional information.

Size-resolved ultrafine particle composition analysis 1. Atlanta

NASA Astrophysics Data System (ADS)

Rhoads, K. P.; Phares, D. J.; Wexler, A. S.; Johnston, M. V.

2003-04-01

During August 1999 as part of the Southern Oxidants Study Supersite Experiment, our group collected size-resolved measurements of the chemical composition of single ambient aerosol particles with a unique real-time laser desorption/ionization mass spectrometry technique. The rapid single-particle mass spectrometry instrument is capable of analyzing "ultrafine" particles with aerodynamic diameters ranging from 0.01 to 1.5 μm. Under the heaviest loading observed in Atlanta, particles were analyzed at a rate of roughly one per second in sizes ranging from 0.1 to 0.2 μm. Nearly 16,000 individual spectra were recorded over the course of the month during both daytime and nighttime sampling periods. Evaluation of the data indicates that the composition of the ultrafine (less than 100 nm) particles is dominated by carbon-containing compounds. Larger particles show varied compositions but typically appeared to have organic carbon characteristics mixed with an inorganic component (e.g., crustal materials, metals, etc.). During the experiment, 70 composition classes were identified. In this paper we report the average spectra and correlations with various meteorological parameters for all major compound classes and a number of minor ones. The major composition classes are identified from the primary peaks in their spectra as organic carbon (about 74% of the particles), potassium (8%), iron (3%), calcium (2%), nitrate (2%), elemental carbon (1.5%), and sodium (1%). Many of these compound classes appeared in repeatable size ranges and quadrants of the wind rose, indicating emission from specific sources.

Probing the Evaporation Dynamics of Mixed SOA/Squalane Particles Using Size-Resolved Composition and Single-Particle Measurements.

PubMed

Robinson, Ellis Shipley; Saleh, Rawad; Donahue, Neil M

2015-08-18

An analysis of the formation and evaporation of mixed-particles containing squalane (a surrogate for hydrophobic primary organic aerosol, POA) and secondary organic aerosol (SOA) is presented. In these experiments, one material (D62-squalane or SOA from α-pinene + O3) was prepared first to serve as surface area for condensation of the other, forming the mixed-particles. The mixed-particles were then subjected to a heating-ramp from 22 to 44 °C. We were able to determine that (1) almost all of the SOA mass is comprised of material less volatile than D62-squalane; (2) AMS collection efficiency in these mixed-particle systems can be parametrized as a function of the relative mass fraction of the components; and (3) the vast majority of D62-squalane is able to evaporate from the mixed particles, and does so on the same time scale regardless of the order of preparation. We also performed two-population mixing experiments to directly test whether D62-squalane and SOA from α-pinene + O3 form a single solution or two separate phases. We find that these two OA types are immiscible, which informs our inference of the morphology of the mixed-particles. If the morphology is core-shell and dictated by the order of preparation, these data indicate that squalane is able to diffuse relatively quickly through the SOA shell, implying that there are no major diffusion limitations.

Heterogeneous chemistry of atmospheric mineral dust particles and their resulting cloud-nucleation properties

NASA Astrophysics Data System (ADS)

Sullivan, Ryan Christopher

Mineral dust particles are a major component of tropospheric aerosol mass and affect regional and global atmospheric chemistry and climate. Dust particles experience heterogeneous reactions with atmospheric gases that alter the gas and particle-phase chemistry. These in turn influence the warm and cold cloud nucleation ability and optical properties of the dust particles. This dissertation investigates the atmospheric chemistry of mineral dust particles and their role in warm cloud nucleation through a combination of synergistic field measurements, laboratory experiments, and theoretical modeling. In-situ measurements made with a single-particle mass spectrometer during the ACE-Asia field campaign in 2001 provide the motivation for this work. The observed mixing state of the individual ambient particles with secondary organic and inorganic components is described in Chapter 2. A large Asian dust storm occurred during the campaign and produced dramatic changes in the aerosol's composition and mixing state. The effect of particle size and mineralogy on the atmospheric processing of individual dust particles is explored in Chapters 3 & 4. Sulfate was found to accumulate preferentially in submicron iron and aluminosilicate-rich dust particles, while nitrate and chloride were enriched in supermicron calcite-rich dust. The mineral dust (and sea salt particles) were also enriched in oxalic acid, the dominant component of water soluble organic carbon. Chapter 5 explores the roles of gas-phase photochemistry and partitioning of the diacids to the alkaline particles in producing this unique behavior. The effect of the dust's mixing state with secondary organic and inorganic components on the dust particles' solubility, hygroscopicity, and thus warm cloud nucleation properties is explored experimentally and theoretically in Chapter 6. Cloud condensation nucleation (CCN) activation curves revealed that while calcium nitrate and calcium chloride particles were very hygroscopic and CCN-active, due to the high solubility of these compounds, calcium sulfate and calcium oxalate were not. Particles composed of these two sparingly soluble compounds had apparent hygroscopicities similar to pure calcium carbonate. This implies that the commonly made assumption that all dust particles become more hygroscopic after atmospheric processing must be revisited. Calcium sulfate and oxalate represent two forms of aged mineral dust particles that remain non-hygroscopic and thus have poor CCN nucleation ability. The particle generation method (dry versus wet) was found to significantly affect the chemistry and hygroscopicity of the aerosolized particles. Finally, in Chapter 7 the timescale for the atmospheric conversion of insoluble calcite particles to soluble, CCN-active calcium nitrate particles was derived from aerosol flow tube experiments. The reaction rate is rapid was used to estimate the conversion of calcite particles to very hygroscopic particles can occur in just a few hours of exposure to tropospheric levels of nitric acid. This process will therefore be controlled by the availability of nitric acid and its precursors, as opposed to the available atmospheric reaction time.

Semianalytical computation of path lines for finite-difference models

USGS Publications Warehouse

Pollock, D.W.

1988-01-01

A semianalytical particle tracking method was developed for use with velocities generated from block-centered finite-difference ground-water flow models. Based on the assumption that each directional velocity component varies linearly within a grid cell in its own coordinate directions, the method allows an analytical expression to be obtained describing the flow path within an individual grid cell. Given the intitial position of a particle anywhere in a cell, the coordinates of any other point along its path line within the cell, and the time of travel between them, can be computed directly. For steady-state systems, the exit point for a particle entering a cell at any arbitrary location can be computed in a single step. By following the particle as it moves from cell to cell, this method can be used to trace the path of a particle through any multidimensional flow field generated from a block-centered finite-difference flow model. -Author

A new type of shotgun ammunition produces unique wound characteristics.

PubMed

Nelson, Craig L; Winston, David C

2007-01-01

The Tucson Police Department, Tucson, AZ, has begun using the Polyshok Impact Reactive Projectile (IRP), a new type of shotgun ammunition that includes a lead bead core that travels within single, plastic-encased projectile. On impact, the core is released to distribute over a small area, thereby disintegrating on impact to reduce the likelihood of exit or collateral damage on missed shots. After a brief review of shotgun slug ballistics and wound characteristics and a discussion of the mechanism of the Polyshok IRP, we report the first death in the United States from this ammunition. Findings included a single entrance wound with plastic ammunition components and small lead particles recovered from the body, the combination of which normally would suggest a close-range shooting with birdshot. However, the characteristics of this ammunition create different patterns than are found with slugs or shot, so that a medical examiner unfamiliar with the Polyshok IRP could draw inaccurate conclusions about ammunition and range of fire. Because the single projectile fired from this ammunition is composed of both plastic and lead, plastic components are likely to be found within the wound at any range of fire, unlike traditional shot or slug ammunition. Also, the small size of lead particles found spread through the wound cavity would ordinarily suggest a small-size shot, whereas the external appearance of the wound (a single entrance with no dispersion of shot) and the pattern of tissue destruction are more consistent with the patterns of injury associated with shotgun slugs.

Modeling of non-stationary local response on impurity penetration in plasma

NASA Astrophysics Data System (ADS)

Tokar, M. Z.; Koltunov, M.

2012-04-01

In fusion devices, strongly localized intensive sources of impurities may arise unexpectedly, e.g., if the wall is excessively demolished by hot plasma particles, or can be created deliberately through impurity seeding. The spreading of impurities from such sources both along and perpendicular to the magnetic field is affected by coulomb collisions with background particles, ionization, acceleration by electric field, etc. Simultaneously, the plasma itself can be significantly disturbed by these interactions. To describe self-consistently the impurity spreading process and the plasma response, three-dimensional fluid equations for the particle, parallel momentum, and energy balances of various plasma components are solved by reducing them to ordinary differential equations for the time evolution of several parameters characterizing the solutions in principal details: the maximum densities of impurity ions of different charges, the dimensions both along and across the magnetic field of the shells occupied by these particles, the characteristic temperatures of all plasma components, and the densities of the main ions and electrons in different shells. The results of modeling for penetration of lithium singly charged particles in tokamak edge plasma are presented. A new mechanism for the condensation phenomenon and formation of cold dense plasma structures, implying an outstanding role of coulomb collisions between main and impurity ions, is proposed.

Cassini Radio Occultations of Saturn's Rings: Scattered Signal and Particle Sizes

NASA Astrophysics Data System (ADS)

Thomson, F.; Wong, K.; Marouf, E.; French, R.; Rappaport, N.; McGhee, C.; Anabtawi, A.; Asmar, S.; Barbinis, E.; Fleischman, D.; Goltz, G.; Johnston, D.; Rochblatt, D.

2005-08-01

Eight Cassini radio occultations of Saturn's rings were conducted from May 3 to September 5, 2005. During any given occultation, Cassini transmits Ka-, X-, and S-band sinusoidal signals (0.94, 3.6, and 13 cm-wavelength) through the rings. Spectral analysis of the perturbed signals received at stations of the Deep Space Network (DSN) reveals two distinct signal components. The first is the direct signal, a narrowband component representing the incident sinusoid emerging from the rings reduced in amplitude and changed in phase. The second is the scattered signal, a broadband component, representing near-forward scattering by ring particles. After reconstruction to remove diffraction effects, time history of the direct signal yields profiles of ring structure at resolution approaching ˜50 m. Of primary concern here is the broadband component. For the first time ever, clearly detectable scattered signals were observed at all three (Ka/X/S) bands. A single X/S radio occultation by Voyager 1 in 1980 detected scattered signal at X-band only, primarily because of the small ring opening angle B=5.9o at the time, compared with 19.1 ≤ B ≤ 23.6o for Cassini. Time histories of the observed spectra (spectrograms) and their dependence on wavelength provide important information about physical ring properties, including abundance of meter-size particles, particle crowding, clustering, spatial anisotropy, vertical ring profile and thickness. Cassini occultation orbits were optimized to map scattering by individual ring features into nearly non-overlapping spectral bands, allowing unambiguous identification of the contribution of ring features to the computed spectrograms. We present Ka/X/S spectrograms over the full extent of the ring system and relate their behavior to observed ring structure. The spectrograms imply presence of meters-size particles throughout the ring system. Preliminary results regarding the particle size distribution and vertical ring profile of selected ring features are presented. Contributions of personnel of the DSN are gratefully acknowledged.

Principal Components Constrain Dynamic Pyrometamorphism in a Partially Melted Interplanetary Dust Particle

NASA Astrophysics Data System (ADS)

Rietmeijer, F. J. M.

1996-03-01

All interplanetary dust particles [IDPs] that decelerate in the Earth's atmosphere experience flash heating whereby their orbital velocity (km s^-1) is reduced to cm s^-1. Iron-oxide rims that may either be continuous on the particle surface, or discontinuous along its perimeter, occur on many IDPs. It is the most conspicuous mineralogical indicator of dynamic pyrometamorphism and its formation is interpreted as 'intense' IDP heating. It appears that the formation of these magnetite and maghemite rims is intimately linked to the presence of Fe,Ni-sulfides in the pre-entry particle. In this regard chondritic porous (CP) IDP L2011K7 may be an unusual particle. This porous aggregate consists of S-free polyphase units (PUs), nonstoichiometric diopside and Mg-rich wollastonite single-crystals and small, accessory Fe,Ni-sulfide grains. Only a few Fe-oxide nanograins are present along its perimeter. The nonstoichiometry of its Ca,Mg-clinopyroxenes indicates incongruent melting or vaporization that was experimentally determined at 1300 degrees-1400 degrees C. The CP IDP L2011K7 is probably of cometary origin since active comet nuclei are the most likely sources for uncompacted aggregate IDPs whereby their low density (< 1 g cm^-3) enhances atmospheric entry survival of large particles. In addition, the fluffy texture which inhibits chemical exchange among its components further enhances their survival unless compaction occurs during deceleration in the Earth's atmosphere.

Characterization of new types of stationary phases for fast and ultra-fast liquid chromatography by signal processing based on AutoCovariance Function: a case study of application to Passiflora incarnata L. extract separations.

PubMed

Pietrogrande, Maria Chiara; Dondi, Francesco; Ciogli, Alessia; Gasparrini, Francesco; Piccin, Antonella; Serafini, Mauro

2010-06-25

In this study, a comparative investigation was performed of HPLC Ascentis (2.7 microm particles) columns based on fused-core particle technology and Acquity (1.7 microm particles) columns requiring UPLC instruments, in comparison with Chromolith RP-18e columns. The study was carried out on mother and vegetal tinctures of Passiflora incarnata L. on one single or two coupled columns. The fundamental attributions of the chromatographic profiles are evaluated using a chemometric procedure, based on the AutoCovariance Function (ACVF). Different chromatographic systems are compared in terms of their separation parameters, i.e., number of total chemical components (m(tot)), separation efficiency (sigma), peak capacity (n(c)), overlap degree of peaks and peak purity. The obtained results show the improvements achieved by HPLC columns with narrow size particles in terms of total analysis time and chromatographic efficiency: comparable performance are achieved by Ascentis (2.7 microm particle) column and Acquity (1.7 microm particle) column requiring UPLC instruments. The ACVF plot is proposed as a simplified tool describing the chromatographic fingerprint to be used for evaluating and comparing chemical composition of plant extracts by using the parameters D% - relative abundance of the deterministic component - and c(EACF) - similarity index computed on ACVF. Copyright 2010 Elsevier B.V. All rights reserved.

Proteins of Vasicular Stomatitis Virus

PubMed Central

Kang, C. Y.; Prevec, L.

1969-01-01

Infection of L cells with vesicular stomatitis virus results in the release, into the cell-free fluid, of four antigenic components separable by rate zonal centrifugation on sucrose gradients. The largest antigens are the infectious (B) particle and a shorter noninfectious, autointerfering (T) particle. The two small antigens are characterized by sedimentation coefficients of approximately 20S and 6S. Treatment of purified B or T particles with sodium deoxycholate results in the release from the particle of a nucleoprotein core which can be purified on sucrose gradient and which has a sedimentation coefficient characteristic of the virus from which it arose. Utilizing purified antigens labeled with 14C-amino acids during growth, we examined the protein constituents of each antigen by acrylamide-gel electrophoresis. The proteins of B and T particles are identical, each containing one minor (virus protein 1) and three major (virus proteins 2, 3, and 4) proteins, numbered in order of increasing mobility. Virus protein 3 originates from the nucleoprotein core, whereas proteins 2 and 4 come from the coat. The origin of virus protein 1 is not known. The 20S antigen contains a single protein equivalent to virus protein 3, whereas the 6S antigen shows a single protein which is similar to, but probably distinct from, virus protein 2. PMID:4306195

Laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF): performance, reference spectra and classification of atmospheric samples

NASA Astrophysics Data System (ADS)

Shen, Xiaoli; Ramisetty, Ramakrishna; Mohr, Claudia; Huang, Wei; Leisner, Thomas; Saathoff, Harald

2018-04-01

The laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF, AeroMegt GmbH) is able to identify the chemical composition and mixing state of individual aerosol particles, and thus is a tool for elucidating their impacts on human health, visibility, ecosystem, and climate. The overall detection efficiency (ODE) of the instrument we use was determined to range from ˜ (0.01 ± 0.01) to ˜ (4.23 ± 2.36) % for polystyrene latex (PSL) in the size range of 200 to 2000 nm, ˜ (0.44 ± 0.19) to ˜ (6.57 ± 2.38) % for ammonium nitrate (NH4NO3), and ˜ (0.14 ± 0.02) to ˜ (1.46 ± 0.08) % for sodium chloride (NaCl) particles in the size range of 300 to 1000 nm. Reference mass spectra of 32 different particle types relevant for atmospheric aerosol (e.g. pure compounds NH4NO3, K2SO4, NaCl, oxalic acid, pinic acid, and pinonic acid; internal mixtures of e.g. salts, secondary organic aerosol, and metallic core-organic shell particles; more complex particles such as soot and dust particles) were determined. Our results show that internally mixed aerosol particles can result in spectra with new clusters of ions, rather than simply a combination of the spectra from the single components. An exemplary 1-day ambient data set was analysed by both classical fuzzy clustering and a reference-spectra-based classification method. Resulting identified particle types were generally well correlated. We show how a combination of both methods can greatly improve the interpretation of single-particle data in field measurements.

Impact of covariate models on the assessment of the air pollution-mortality association in a single- and multipollutant context.

PubMed

Sacks, Jason D; Ito, Kazuhiko; Wilson, William E; Neas, Lucas M

2012-10-01

With the advent of multicity studies, uniform statistical approaches have been developed to examine air pollution-mortality associations across cities. To assess the sensitivity of the air pollution-mortality association to different model specifications in a single and multipollutant context, the authors applied various regression models developed in previous multicity time-series studies of air pollution and mortality to data from Philadelphia, Pennsylvania (May 1992-September 1995). Single-pollutant analyses used daily cardiovascular mortality, fine particulate matter (particles with an aerodynamic diameter ≤2.5 µm; PM(2.5)), speciated PM(2.5), and gaseous pollutant data, while multipollutant analyses used source factors identified through principal component analysis. In single-pollutant analyses, risk estimates were relatively consistent across models for most PM(2.5) components and gaseous pollutants. However, risk estimates were inconsistent for ozone in all-year and warm-season analyses. Principal component analysis yielded factors with species associated with traffic, crustal material, residual oil, and coal. Risk estimates for these factors exhibited less sensitivity to alternative regression models compared with single-pollutant models. Factors associated with traffic and crustal material showed consistently positive associations in the warm season, while the coal combustion factor showed consistently positive associations in the cold season. Overall, mortality risk estimates examined using a source-oriented approach yielded more stable and precise risk estimates, compared with single-pollutant analyses.

The role of pore geometry in single nanoparticle detection

DOE PAGES

Davenport, Matthew; Healy, Ken; Pevarnik, Matthew; ...

2012-08-22

In this study, we observe single nanoparticle translocation events via resistive pulse sensing using silicon nitride pores described by a range of lengths and diameters. Pores are prepared by focused ion beam milling in 50 nm-, 100 nm-, and 500 nm-thick silicon nitride membranes with diameters fabricated to accommodate spherical silica nanoparticles with sizes chosen to mimic that of virus particles. In this manner, we are able to characterize the role of pore geometry in three key components of the detection scheme, namely, event magnitude, event duration, and event frequency. We find that the electric field created by the appliedmore » voltage and the pore’s geometry is a critical factor. We develop approximations to describe this field, which are verified with computer simulations, and interactions between particles and this field. In so doing, we formulate what we believe to be the first approximation for the magnitude of ionic current blockage that explicitly addresses the invariance of access resistance of solid-state pores during particle translocation. These approximations also provide a suitable foundation for estimating the zeta potential of the particles and/or pore surface when studied in conjunction with event durations. We also verify that translocation achieved by electro-osmostic transport is an effective means of slowing translocation velocities of highly charged particles without compromising particle capture rate as compared to more traditional approaches based on electrophoretic transport.« less

Methods used to calculate doses resulting from inhalation of Capstone depleted uranium aerosols.

PubMed

Miller, Guthrie; Cheng, Yung Sung; Traub, Richard J; Little, Tom T; Guilmette, Raymond A

2009-03-01

The methods used to calculate radiological and toxicological doses to hypothetical persons inside either a U.S. Army Abrams tank or Bradley Fighting Vehicle that has been perforated by depleted uranium munitions are described. Data from time- and particle-size-resolved measurements of depleted uranium aerosol as well as particle-size-resolved measurements of aerosol solubility in lung fluids for aerosol produced in the breathing zones of the hypothetical occupants were used. The aerosol was approximated as a mixture of nine monodisperse (single particle size) components corresponding to particle size increments measured by the eight stages plus the backup filter of the cascade impactors used. A Markov Chain Monte Carlo Bayesian analysis technique was employed, which straightforwardly calculates the uncertainties in doses. Extensive quality control checking of the various computer codes used is described.

Selective laser processing of ink-jet printed nano-scaled tin-clad copper particles

NASA Astrophysics Data System (ADS)

Yung, K. C.; Plura, T. S.

2010-11-01

The deposition of tin-clad nano-size copper particles was carried out by means of ink-jet printing. Curing the particles on Polyimide (PI) turned them into soldered structures using an Nd-YAG laser. Area coverage of 55% was achieved for a single-layer print. Subsequent laser sintering increased this value to 95%. A Butanol-based copper ink and an aqueous tin (Sn)-clad Copper (Cu) ink were produced and were ink-jetted in this work. These nano-metallic inks showed excellent suspension stability with particle weight concentrations as high as 5%. The ink components were examined by measuring the particle size distribution in a dispersed condition, and the melting temperature. A piezo ink-jet print head was used to deposit the inks onto a moveable substrate. The thermal effect of the laser irradiation allowed approaching and connecting adjacent particles by melting the particle’s tin coating. The results were examined with regard to structure and soldering properties using EDX, SEM and optical microscopy.

Nanomaterial release characteristics in a single-walled carbon nanotube manufacturing workplace

NASA Astrophysics Data System (ADS)

Ji, Jun Ho; Kim, Jong Bum; Lee, Gwangjae; Bae, Gwi-Nam

2015-02-01

As carbon nanotubes (CNTs) are widely used in various applications, exposure assessment also increases in importance with other various toxicity tests for CNTs. We conducted 24-h continuous nanoaerosol measurements to identify possible nanomaterial release in a single-walled carbon nanotube (SWCNT) manufacturing workplace. Four real-time aerosol instruments were used to determine the nanosized and microsized particle numbers, particle surface area, and carbonaceous species. Task-based exposure assessment was carried out for SWCNT synthesis using the arc plasma and thermal decomposition processes to remove amorphous carbon components as impurities. During the SWCNT synthesis, the black carbon (BC) concentration was 2-12 μg/m3. The maximum BC mass concentrations occurred when the synthesis chamber was opened for harvesting the SWCNTs. The number concentrations of particles with sizes 10-420 nm were 10,000-40,000 particles/cm3 during the tasks. The maximum number concentration existed when a vacuum pump was operated to remove exhaust air from the SWCNT synthesis chamber due to the penetration of highly concentrated oil mists through the window opened. We analyzed the particle mass size distribution and particle number size distribution for each peak episode. Using real-time aerosol detectors, we distinguished the SWCNT releases from background nanoaerosols such as oil mist and atmospheric photochemical smog particles. SWCNT aggregates with sizes of 1-10 μm were mainly released from the arc plasma synthesis. The harvesting process was the main release route of SWCNTs in the workplace.

Characteristics of tyre dust in polluted air: Studies by single particle mass spectrometry (ATOFMS)

NASA Astrophysics Data System (ADS)

Dall'Osto, Manuel; Beddows, David C. S.; Gietl, Johanna K.; Olatunbosun, Oluremi A.; Yang, Xiaoguang; Harrison, Roy M.

2014-09-01

There is a paucity of quantitative knowledge on the contributions of non-exhaust (abrasion and re-suspension) sources to traffic emissions. Abrasive emissions can be broadly categorised as tyre wear, brake wear and road dust/road surface wear. Current research often considers road dust and tyre dust as externally mixed particles, the former mainly composed of mineral matter and the latter solely composed of mainly organic matter and some trace elements. The aim of this work was to characterise tyre wear from both laboratory and field studies by using Aerosol Time-Of-Flight Mass Spectrometry (ATOFMS). Real-time single particle chemical composition was obtained from a set of rubber tyres rotating on a metal surface. Bimodal particle number size distributions peaking at 35 nm and 85 nm were obtained from SMPS/APS measurements over the range 6-20,000 nm. ATOFMS mass spectra of tyre wear in the particle size range 200-3000 nm diameter show peaks due to exo-sulphur compounds, nitrate, Zn and ions of high molecular weight (m/z > 100) attributed to organic polymers. Two large ATOFMS datasets collected from a number of outdoor studies were examined. The former was constituted of 48 road dust samples collected on the roads of London. The latter consisted of ATOFMS ambient air field studies from Europe, overall composed of more than 2,000,000 single particle mass spectra. The majority (95%) of tyre wear particles present in the road dust samples and atmospheric samples are internally mixed with metals (Li, Na, Ca, Fe, Ti), as well as phosphate. It is concluded that the interaction of tyres with the road surface creates particles internally mixed from two sources: tyre rubber and road surface materials. Measurements of the tyre rubber component alone may underestimate the contribution of tyre wear to concentrations of airborne particulate matter. The results presented are especially relevant for urban aerosol source apportionment and PM2.5 exposure assessment.

Three-dimensional simulation of free-electron laser harmonics with FRED

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharp, W.M.; Scharlemann, E.T.; Fawley, W.M.

1989-11-20

FRED3D, a single-mode three-dimensional version of the FEL simulation code FRED, has been modified to follow the growth of signal components at the fundamental frequency and at even and odd harmonics. The Wiggle-averaged particle and field equations for this multi-mode formulation are derived here, and their implementation in FRED3D is discussed. 12 refs.

Annual Conference on Nuclear and Space Radiation Effects, 17th, Cornell University, Ithaca, N.Y., July 15-18, 1980, Proceedings

NASA Technical Reports Server (NTRS)

Mcgarrity, J. M.

1980-01-01

The conference covered the radiation effects on devices, circuits, and systems, physics and basic radiation effects in materials, dosimetry and radiation transport, spacecraft charging, and space radiation effects. Other subjects included single particle upset phenomena, systems-generated electromagnetic pulse phenomena, fabrication of hardened components, testing techniques, and hardness assurance.

Colloidal transport phenomena of milk components during convective droplet drying.

PubMed

Fu, Nan; Woo, Meng Wai; Chen, Xiao Dong

2011-10-15

Material segregation has been reported for industrial spray-dried milk powders, which indicates potential material migration during drying process. The relevant colloidal transport phenomenon and the underlying mechanism are still under debate. This study extended the glass-filament single droplet drying technique to observe not only the drying behaviour but also the dissolution behaviour of the correspondingly dried single particle. At progressively longer drying stage, a solvent droplet (water or ethanol) was attached to the semi-dried milk particle and the interaction between the solvent and the particle was video-recorded. Based on the different dissolution and wetting behaviours observed, material migration during milk drying was studied. Fresh skim milk and fresh whole milk were investigated using water and ethanol as solvents. Fat started to accumulate on the surface as soon as drying was started. At the initial stage of drying, the fat layer remained thin and the solubility of the semi-dried milk particle was much affected by lactose and protein present underneath the fat layer. Fat kept accumulating at the surface as drying progressed and the accumulation was completed by the middle stage of drying. The results from drying of model milk materials (pure sodium caseinate solution and lactose/sodium caseinate mixed solution) supported the colloidal transport phenomena observed for the milk drying. When mixed with lactose, sodium caseinate did not form an apparent solvent-resistant protein shell during drying. The extended technique of glass-filament single droplet approach provides a powerful tool in examining the solubility of individual particle after drying. Copyright © 2011 Elsevier B.V. All rights reserved.

Chemical aging of single and multicomponent biomass burning aerosol surrogate-particles by OH: Implications for cloud condensation nucleus activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thalman, R.; Thalman, R.; Wang, J.

Multiphase OH and O₃ oxidation reactions with atmospheric organic aerosol (OA) can influence particle physicochemical properties including composition, morphology, and lifetime. Chemical aging of initially insoluble or low soluble single-component OA by OH and O₃ can increase their water-solubility and hygroscopicity, making them more active as cloud condensation nuclei (CCN) and susceptible to wet deposition. However, an outstanding problem is whether the effects of chemical aging on their CCN activity are preserved when mixed with other organic or inorganic compounds exhibiting greater water-solubility. In this work, the CCN activity of laboratory-generated biomass burning aerosol (BBA) surrogate-particles exposed to OH andmore » O₃ is evaluated by determining the hygroscopicity parameter, κ, as a function of particle type, mixing state, and OH/O₃ exposure applying a CCN counter (CCNc) coupled to an aerosol flow reactor (AFR). Levoglucosan (LEV), 4-methyl-5-nitrocatechol (MNC), and potassium sulfate (KS) serve as representative BBA compounds that exhibit different hygroscopicity, water solubility, chemical functionalities, and reactivity with OH radicals, and thus exemplify the complexity of mixed inorganic/organic aerosol in the atmosphere. The CCN activities of all of the particles were unaffected by O₃ exposure. Following exposure to OH, κ of MNC was enhanced by an order of magnitude, from 0.009 to ~0.1, indicating that chemically-aged MNC particles are better CCN and more prone to wet deposition than pure MNC particles. No significant enhancement in κ was observed for pure LEV particles following OH exposure. κ of the internally-mixed particles was not affected by OH oxidation. Furthermore, the CCN activity of OH exposed MNC-coated KS particles is similar to the OH unexposed atomized 1:1 by mass MNC: KS binary-component particles. Our results strongly suggest that when OA is dominated by water-soluble organic carbon (WSOC) or inorganic ions, chemical aging has no significant impact on OA hygroscopicity. The organic compounds exhibiting low solubility behave as if they are infinitely soluble when mixed with a sufficient amount of water-soluble compounds. At and beyond this point, the particles' CCN activity is governed entirely by the water-soluble fraction and not influenced by the oxidized organic fraction. Our results have important implications for heterogeneous oxidation and its impact on cloud formation given that atmospheric aerosol is a complex mixture of organic and inorganic compounds exhibiting a wide-range of solubilities.« less

Chemical aging of single and multicomponent biomass burning aerosol surrogate-particles by OH: Implications for cloud condensation nucleus activity

DOE PAGES

Thalman, R.; Thalman, R.; Wang, J.; ...

2015-03-06

Multiphase OH and O₃ oxidation reactions with atmospheric organic aerosol (OA) can influence particle physicochemical properties including composition, morphology, and lifetime. Chemical aging of initially insoluble or low soluble single-component OA by OH and O₃ can increase their water-solubility and hygroscopicity, making them more active as cloud condensation nuclei (CCN) and susceptible to wet deposition. However, an outstanding problem is whether the effects of chemical aging on their CCN activity are preserved when mixed with other organic or inorganic compounds exhibiting greater water-solubility. In this work, the CCN activity of laboratory-generated biomass burning aerosol (BBA) surrogate-particles exposed to OH andmore » O₃ is evaluated by determining the hygroscopicity parameter, κ, as a function of particle type, mixing state, and OH/O₃ exposure applying a CCN counter (CCNc) coupled to an aerosol flow reactor (AFR). Levoglucosan (LEV), 4-methyl-5-nitrocatechol (MNC), and potassium sulfate (KS) serve as representative BBA compounds that exhibit different hygroscopicity, water solubility, chemical functionalities, and reactivity with OH radicals, and thus exemplify the complexity of mixed inorganic/organic aerosol in the atmosphere. The CCN activities of all of the particles were unaffected by O₃ exposure. Following exposure to OH, κ of MNC was enhanced by an order of magnitude, from 0.009 to ~0.1, indicating that chemically-aged MNC particles are better CCN and more prone to wet deposition than pure MNC particles. No significant enhancement in κ was observed for pure LEV particles following OH exposure. κ of the internally-mixed particles was not affected by OH oxidation. Furthermore, the CCN activity of OH exposed MNC-coated KS particles is similar to the OH unexposed atomized 1:1 by mass MNC: KS binary-component particles. Our results strongly suggest that when OA is dominated by water-soluble organic carbon (WSOC) or inorganic ions, chemical aging has no significant impact on OA hygroscopicity. The organic compounds exhibiting low solubility behave as if they are infinitely soluble when mixed with a sufficient amount of water-soluble compounds. At and beyond this point, the particles' CCN activity is governed entirely by the water-soluble fraction and not influenced by the oxidized organic fraction. Our results have important implications for heterogeneous oxidation and its impact on cloud formation given that atmospheric aerosol is a complex mixture of organic and inorganic compounds exhibiting a wide-range of solubilities.« less

Pulmonary epithelial response in the rat lung to instilled Montserrat respirable dusts and their major mineral components.

PubMed

Housley, D G; Bérubé, K A; Jones, T P; Anderson, S; Pooley, F D; Richards, R J

2002-07-01

The Soufriere Hills, a stratovolcano on Montserrat, started erupting in July 1995, producing volcanic ash, both from dome collapse pyroclastic flows and phreatic explosions. The eruptions/ash resuspension result in high concentrations of suspended particulate matter in the atmosphere, which includes cristobalite, a mineral implicated in respiratory disorders. To conduct toxicological studies on characterised samples of ash, together with major components of the dust mixture (anorthite, cristobalite), and a bioreactive mineral control (DQ12 quartz). Rats were challenged with a single mass (1 mg) dose of particles via intratracheal instillation and groups sacrificed at one, three, and nine weeks. Acute bioreactivity of the particles was assessed by increases in lung permeability and inflammation, changes in epithelial cell markers, and increase in the size of bronchothoracic lymph nodes. Data indicated that respirable ash derived from pyroclastic flows (20.1% cristobalite) or phreatic explosion (8.6% cristobalite) had minimal bioreactivity in the lung. Anorthite showed low bioreactivity, in contrast to pure cristobalite, which showed progressive increases in lung damage. Results suggests that either the percentage mass of cristobalite particles present in Montserrat ash was not sufficient as a catalyst in the lung environment, or its surface reactivity was masked by the non-reactive volcanic glass components during the process of ash formation.

"Self-Shaping" of Multicomponent Drops.

PubMed

Cholakova, Diana; Valkova, Zhulieta; Tcholakova, Slavka; Denkov, Nikolai; Smoukov, Stoyan K

2017-06-13

In our recent study we showed that single-component emulsion drops, stabilized by proper surfactants, can spontaneously break symmetry and transform into various polygonal shapes during cooling [ Denkov Nature 2015 , 528 , 392 - 395 ]. This process involves the formation of a plastic rotator phase of self-assembled oil molecules beneath the drop surface. The plastic phase spontaneously forms a frame of plastic rods at the oil drop perimeter which supports the polygonal shapes. However, most of the common substances used in industry appear as mixtures of molecules rather than pure substances. Here we present a systematic study of the ability of multicomponent emulsion drops to deform upon cooling. The observed trends can be summarized as follows: (1) The general drop-shape evolution for multicomponent drops during cooling is the same as with single-component drops; however, some additional shapes are observed. (2) Preservation of the particle shape upon freezing is possible for alkane mixtures with chain length difference Δn ≤ 4; for greater Δn, phase separation within the droplet is observed. (3) Multicomponent particles prepared from alkanes with Δn ≤ 4 plastify upon cooling due to the formation of a bulk rotator phase within the particles. (4) If a compound, which cannot induce self-shaping when pure, is mixed with a certain amount of a compound which induces self-shaping, then drops prepared from this mixture can also self-shape upon cooling. (5) Self-emulsification phenomena are also observed for multicomponent drops. In addition to the three recently reported mechanisms of self-emulsification [ Tcholakova Nat. Commun. 2017 , ( 8 ), 15012 ], a new (fourth) mechanism is observed upon freezing for alkane mixtures with Δn > 4. It involves disintegration of the particles due to a phase separation of alkanes upon freezing.

Volumetric particle image velocimetry with a single plenoptic camera

NASA Astrophysics Data System (ADS)

Fahringer, Timothy W.; Lynch, Kyle P.; Thurow, Brian S.

2015-11-01

A novel three-dimensional (3D), three-component (3C) particle image velocimetry (PIV) technique based on volume illumination and light field imaging with a single plenoptic camera is described. A plenoptic camera uses a densely packed microlens array mounted near a high resolution image sensor to sample the spatial and angular distribution of light collected by the camera. The multiplicative algebraic reconstruction technique (MART) computed tomography algorithm is used to reconstruct a volumetric intensity field from individual snapshots and a cross-correlation algorithm is used to estimate the velocity field from a pair of reconstructed particle volumes. This work provides an introduction to the basic concepts of light field imaging with a plenoptic camera and describes the unique implementation of MART in the context of plenoptic image data for 3D/3C PIV measurements. Simulations of a plenoptic camera using geometric optics are used to generate synthetic plenoptic particle images, which are subsequently used to estimate the quality of particle volume reconstructions at various particle number densities. 3D reconstructions using this method produce reconstructed particles that are elongated by a factor of approximately 4 along the optical axis of the camera. A simulated 3D Gaussian vortex is used to test the capability of single camera plenoptic PIV to produce a 3D/3C vector field, where it was found that lateral displacements could be measured to approximately 0.2 voxel accuracy in the lateral direction and 1 voxel in the depth direction over a 300× 200× 200 voxel volume. The feasibility of the technique is demonstrated experimentally using a home-built plenoptic camera based on a 16-megapixel interline CCD camera and a 289× 193 array of microlenses and a pulsed Nd:YAG laser. 3D/3C measurements were performed in the wake of a low Reynolds number circular cylinder and compared with measurements made using a conventional 2D/2C PIV system. Overall, single camera plenoptic PIV is shown to be a viable 3D/3C velocimetry technique.

Transforming single DNA molecules into fluorescent magnetic particles for detection and enumeration of genetic variations

PubMed Central

Dressman, Devin; Yan, Hai; Traverso, Giovanni; Kinzler, Kenneth W.; Vogelstein, Bert

2003-01-01

Many areas of biomedical research depend on the analysis of uncommon variations in individual genes or transcripts. Here we describe a method that can quantify such variation at a scale and ease heretofore unattainable. Each DNA molecule in a collection of such molecules is converted into a single magnetic particle to which thousands of copies of DNA identical in sequence to the original are bound. This population of beads then corresponds to a one-to-one representation of the starting DNA molecules. Variation within the original population of DNA molecules can then be simply assessed by counting fluorescently labeled particles via flow cytometry. This approach is called BEAMing on the basis of four of its principal components (beads, emulsion, amplification, and magnetics). Millions of individual DNA molecules can be assessed in this fashion with standard laboratory equipment. Moreover, specific variants can be isolated by flow sorting and used for further experimentation. BEAMing can be used for the identification and quantification of rare mutations as well as to study variations in gene sequences or transcripts in specific populations or tissues. PMID:12857956

Biocompatible Er, Yb co-doped fluoroapatite upconversion nanoparticles for imaging applications

NASA Astrophysics Data System (ADS)

Anjana, R.; K. M., Kurias; M. K., Jayaraj

2017-08-01

Upconversion luminescence, visible emission on infra red (IR) excitation was achieved in a biocompatible material, fluoroapatite. Fluoroapatite crystals are well known biomaterials, which is a component of tooth enamel. Also it can be considered as an excellent host material for lanthanide doping since the ionic radii of lanthanide is similar to that of calcium ion(Ca2+) hence successful incorporation of dopants within the lattice is possible. Erbium (Er), Ytterbium (Yb) co-doped fluorapatite (FAp) nanoparticles were prepared by precipitation method. The particles show intense visible emission when excited with 980 nm laser. Since upconversion luminescence is a multiphoton process the excitation power dependence on emission will give number of photons involved in the emission of single photon. Excitation power dependence studies show that two photons are involved in the emission of single photons. The value of slope was different for different emission peak because of the difference in intermediate energy level involved. The crystal structure and morphology of the particle were determined using X-ray diffractometer (XRD) and field emission scanning electron microscope (FESEM). These particles with surface functionalisation can be used for live cell imaging.

The Microwave Radiative Properties of Falling Snow Derived from Nonspherical Ice Particle Models. Part II: Initial Testing Using Radar, Radiometer and In Situ Observations

NASA Technical Reports Server (NTRS)

Olson, William S.; Tian, Lin; Grecu, Mircea; Kuo, Kwo-Sen; Johnson, Benjamin; Heymsfield, Andrew J.; Bansemer, Aaron; Heymsfield, Gerald M.; Wang, James R.; Meneghini, Robert

2016-01-01

In this study, two different particle models describing the structure and electromagnetic properties of snow are developed and evaluated for potential use in satellite combined radar-radiometer precipitation estimation algorithms. In the first model, snow particles are assumed to be homogeneous ice-air spheres with single-scattering properties derived from Mie theory. In the second model, snow particles are created by simulating the self-collection of pristine ice crystals into aggregate particles of different sizes, using different numbers and habits of the collected component crystals. Single-scattering properties of the resulting nonspherical snow particles are determined using the discrete dipole approximation. The size-distribution-integrated scattering properties of the spherical and nonspherical snow particles are incorporated into a dual-wavelength radar profiling algorithm that is applied to 14- and 34-GHz observations of stratiform precipitation from the ER-2 aircraft-borne High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) radar. The retrieved ice precipitation profiles are then input to a forward radiative transfer calculation in an attempt to simulate coincident radiance observations from the Conical Scanning Millimeter-Wave Imaging Radiometer (CoSMIR). Much greater consistency between the simulated and observed CoSMIR radiances is obtained using estimated profiles that are based upon the nonspherical crystal/aggregate snow particle model. Despite this greater consistency, there remain some discrepancies between the higher moments of the HIWRAP-retrieved precipitation size distributions and in situ distributions derived from microphysics probe observations obtained from Citation aircraft underflights of the ER-2. These discrepancies can only be eliminated if a subset of lower-density crystal/aggregate snow particles is assumed in the radar algorithm and in the interpretation of the in situ data.

Cylinders vs. Spheres: Biofluid Shear Thinning in Driven Nanoparticle Transport

PubMed Central

Cribb, Jeremy A.; Meehan, Timothy D.; Shah, Sheel M.; Skinner, Kwan; Superfine, Richard

2011-01-01

Increasingly, the research community applies magnetophoresis to micro and nanoscale particles for drug delivery applications and the nanoscale rheological characterization of complex biological materials. Of particular interest is the design and transport of these magnetic particles through entangled polymeric fluids commonly found in biological systems. We report the magnetophoretic transport of spherical and rod-shaped particles through viscoelastic, entangled solutions using lambda-phage DNA (λ-DNA) as a model system. In order to understand and predict the observed phenomena, we fully characterize three fundamental components: the magnetic field and field gradient, the shape and magnetic properties of the probe particles, and the macroscopic rheology of the solution. Particle velocities obtained in Newtonian solutions correspond to macroscale rheology, with forces calculated via Stokes Law. In λ-DNA solutions, nanorod velocities are 100 times larger than predicted by measured zero-shear viscosity. These results are consistent with particles experiencing transport through a shear thinning fluid, indicating magnetically driven transport in shear thinning may be especially effective and favor narrow diameter, high aspect ratio particles. A complete framework for designing single-particle magnetic-based delivery systems results when we combine a quantified magnetic system with qualified particles embedded in a characterized viscoelastic medium. PMID:20571853

Concept of a utility scale dispatch able solar thermal electricity plant with an indirect particle receiver in a single tower layout

NASA Astrophysics Data System (ADS)

Schwaiger, Karl; Haider, Markus; Haemmerle, Martin; Steiner, Peter; Obermaier, Michael-Dario

2016-05-01

Flexible dispatch able solar thermal electricity plants applying state of the art power cycles have the potential of playing a vital role in modern electricity systems and even participating in the ancillary market. By replacing molten salt via particles, operation temperatures can be increased and plant efficiencies of over 45 % can be reached. In this work the concept for a utility scale plant using corundum as storage/heat transfer material is thermodynamically modeled and its key performance data are cited. A novel indirect fluidized bed particle receiver concept is presented, profiting from a near black body behavior being able to heat up large particle flows by realizing temperature cycles over 500°C. Specialized fluidized bed steam-generators are applied with negligible auxiliary power demand. The performance of the key components is discussed and a rough sketch of the plant is provided.

DNA-controlled assembly of a NaTl lattice structure from gold nanoparticles and protein nanoparticles

NASA Astrophysics Data System (ADS)

Cigler, Petr; Lytton-Jean, Abigail K. R.; Anderson, Daniel G.; Finn, M. G.; Park, Sung Yong

2010-11-01

The formation of diamond structures from tailorable building blocks is an important goal in colloidal crystallization because the non-compact diamond lattice is an essential component of photonic crystals for the visible-light range. However, designing nanoparticle systems that self-assemble into non-compact structures has proved difficult. Although several methods have been proposed, single-component nanoparticle assembly of a diamond structure has not been reported. Binary systems, in which at least one component is arranged in a diamond lattice, provide alternatives, but control of interparticle interactions is critical to this approach. DNA has been used for this purpose in a number of systems. Here we show the creation of a non-compact lattice by DNA-programmed crystallization using surface-modified Qβ phage capsid particles and gold nanoparticles, engineered to have similar effective radii. When combined with the proper connecting oligonucleotides, these components form NaTl-type colloidal crystalline structures containing interpenetrating organic and inorganic diamond lattices, as determined by small-angle X-ray scattering. DNA control of assembly is therefore shown to be compatible with particles possessing very different properties, as long as they are amenable to surface modification.

Chemical aging of single and multicomponent biomass burning aerosol surrogate particles by OH: implications for cloud condensation nucleus activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slade, J. H.; Thalman, R.; Wang, J.

Multiphase OH and O 3 oxidation reactions with atmospheric organic aerosol (OA) can influence particle physicochemical properties including composition, morphology, and lifetime. Chemical aging of initially insoluble or low-soluble single-component OA by OH and O 3 can increase their water solubility and hygroscopicity, making them more active as cloud condensation nuclei (CCN) and susceptible to wet deposition. However, an outstanding problem is whether the effects of chemical aging on their CCN activity are preserved when mixed with other organic or inorganic compounds exhibiting greater water solubility. In this work, the CCN activity of laboratory-generated biomass burning aerosol (BBA) surrogate particlesmore » exposed to OH and O 3 is evaluated by determining the hygroscopicity parameter, κ, as a function of particle type, mixing state, and OH and O 3 exposure applying a CCN counter (CCNc) coupled to an aerosol flow reactor (AFR). Levoglucosan (LEV), 4-methyl-5-nitrocatechol (MNC), and potassium sulfate (KS) serve as representative BBA compounds that exhibit different hygroscopicity, water solubility, chemical functionalities, and reactivity with OH radicals, and thus exemplify the complexity of mixed inorganic/organic aerosol in the atmosphere. The CCN activities of all of the particles were unaffected by O 3 exposure. Following exposure to OH, κ of MNC was enhanced by an order of magnitude, from 0.009 to ~ 0.1, indicating that chemically aged MNC particles are better CCN and more prone to wet deposition than pure MNC particles. No significant enhancement in κ was observed for pure LEV particles following OH exposure. κ of the internally mixed particles was not affected by OH oxidation. Furthermore, the CCN activity of OH-exposed MNC-coated KS particles is similar to the OH unexposed atomized 1 : 1 by mass MNC : KS binary-component particles. Our results strongly suggest that when OA is dominated by water-soluble organic carbon (WSOC) or inorganic ions, chemical aging has no significant impact on OA hygroscopicity. The organic compounds exhibiting low solubility behave as if they are infinitely soluble when mixed with a sufficient number of water-soluble compounds. At and beyond this point, the particles' CCN activity is governed entirely by the water-soluble fraction and is not influenced by the oxidized organic fraction. Our results have important implications for heterogeneous oxidation and its impact on cloud formation given that atmospheric aerosol is a complex mixture of organic and inorganic compounds exhibiting a wide range of solubilities.« less

Chemical aging of single and multicomponent biomass burning aerosol surrogate particles by OH: implications for cloud condensation nucleus activity

DOE PAGES

Slade, J. H.; Thalman, R.; Wang, J.; ...

2015-09-14

Multiphase OH and O 3 oxidation reactions with atmospheric organic aerosol (OA) can influence particle physicochemical properties including composition, morphology, and lifetime. Chemical aging of initially insoluble or low-soluble single-component OA by OH and O 3 can increase their water solubility and hygroscopicity, making them more active as cloud condensation nuclei (CCN) and susceptible to wet deposition. However, an outstanding problem is whether the effects of chemical aging on their CCN activity are preserved when mixed with other organic or inorganic compounds exhibiting greater water solubility. In this work, the CCN activity of laboratory-generated biomass burning aerosol (BBA) surrogate particlesmore » exposed to OH and O 3 is evaluated by determining the hygroscopicity parameter, κ, as a function of particle type, mixing state, and OH and O 3 exposure applying a CCN counter (CCNc) coupled to an aerosol flow reactor (AFR). Levoglucosan (LEV), 4-methyl-5-nitrocatechol (MNC), and potassium sulfate (KS) serve as representative BBA compounds that exhibit different hygroscopicity, water solubility, chemical functionalities, and reactivity with OH radicals, and thus exemplify the complexity of mixed inorganic/organic aerosol in the atmosphere. The CCN activities of all of the particles were unaffected by O 3 exposure. Following exposure to OH, κ of MNC was enhanced by an order of magnitude, from 0.009 to ~ 0.1, indicating that chemically aged MNC particles are better CCN and more prone to wet deposition than pure MNC particles. No significant enhancement in κ was observed for pure LEV particles following OH exposure. κ of the internally mixed particles was not affected by OH oxidation. Furthermore, the CCN activity of OH-exposed MNC-coated KS particles is similar to the OH unexposed atomized 1 : 1 by mass MNC : KS binary-component particles. Our results strongly suggest that when OA is dominated by water-soluble organic carbon (WSOC) or inorganic ions, chemical aging has no significant impact on OA hygroscopicity. The organic compounds exhibiting low solubility behave as if they are infinitely soluble when mixed with a sufficient number of water-soluble compounds. At and beyond this point, the particles' CCN activity is governed entirely by the water-soluble fraction and is not influenced by the oxidized organic fraction. Our results have important implications for heterogeneous oxidation and its impact on cloud formation given that atmospheric aerosol is a complex mixture of organic and inorganic compounds exhibiting a wide range of solubilities.« less

2D- and 3D SIMS investigations on hot-pressed steel powder HS 6-5-3-8.

PubMed

Rosner, M; Pöckl, G; Danninger, H; Hutter, H

2002-10-01

Processing of steel with powder metallurgical methods such as sintering or hot-pressing have proven to be a powerful tool for the production of industrial parts and for components in the automotive industry. Series of steel-powders (HS 6-5-3-8) produced by gas atomization has been hot-pressed in a graphite tube at temperatures from 820 degrees C to 1050 degrees C. The samples have been characterized with a Secondary Electron Microscope (SEM) due to their porosity and then investigated with 2D- and 3D- SIMS. The spatial distribution of the non-metallic impurities and the covering oxide layer of the single particles has been traced dependent to the pressing temperature. Powders pressed at temperatures higher than 880 degrees C exhibited different precipitation behavior of the impurities and an excessive loss of the covering oxide layer of the single powder particles.

Magnetosheath-ionspheric plasma interactions in the cusp/cleft. 2: Mesoscale particle simulations

NASA Technical Reports Server (NTRS)

Winglee, R. M.; Menietti, J. D.; Lin, C. S.

1993-01-01

Ionospheric plasma flowing out from the cusp can be an important source of plasma to the magnetosphere. One source of free energy that can drive this outflow is the injection of magnetosheath plasma into the cusp. Two-dimensional (three velocity) mesoscale particle simulations are used to investigate the particle dynamics in the cusp during southward interplanetary magnetic field. This mesoscale model self-consistently incorporates (1) global influences such as the convection of plasma across the cusp, the action of the mirror force, and the injection of the magnetosheath plasma, and (2) wave-particle interactions which produce the actual coupling between the magnetosheath and ionospheric plasmas. It is shown that, because the thermal speed of the electrons is higher than the bulk motion of the magnetosheath plasma, an upward current is formed on the equatorward edge of the injection region with return currents on either side. However, the poleward return currents are the stronger due to the convection and mirroring of many of the magnetosheath electrons. The electron distribution in this latter region evolves from upward directed streams to single-sided loss cones or possibly electron conics. The ion distribution also shows a variety of distinct features that are produced by spatial and/or temporal effects associated with varying convection patterns and wave-particle interactions. On the equatorward edge the distribution has a downflowing magnetosheath component and an upflowing cold ionospheric component due to continuous convection of ionospheric plasma into the region. In the center of the magnetosheath region, heating from the development of an ion-ion streaming instability causes the suppression of the cold ionospheric component and the formation of downward ionospheric streams. Further poleward there is velocity filtering of ions with low pitch angles, so that the magnetosheath ions develop a ring-beam distribution and the ensuing wave instabilities generate downward ionospheric conics. These downward ionospheric components are eventually turned by the mirror force, leading to the production of upward conics at elevated energies throughout the region.

Investigation of HZETRN 2010 as a Tool for Single Event Effect Qualification of Avionics Systems

NASA Technical Reports Server (NTRS)

Rojdev, Kristina; Koontz, Steve; Atwell, William; Boeder, Paul

2014-01-01

NASA's future missions are focused on long-duration deep space missions for human exploration which offers no options for a quick emergency return to Earth. The combination of long mission duration with no quick emergency return option leads to unprecedented spacecraft system safety and reliability requirements. It is important that spacecraft avionics systems for human deep space missions are not susceptible to Single Event Effect (SEE) failures caused by space radiation (primarily the continuous galactic cosmic ray background and the occasional solar particle event) interactions with electronic components and systems. SEE effects are typically managed during the design, development, and test (DD&T) phase of spacecraft development by using heritage hardware (if possible) and through extensive component level testing, followed by system level failure analysis tasks that are both time consuming and costly. The ultimate product of the SEE DD&T program is a prediction of spacecraft avionics reliability in the flight environment produced using various nuclear reaction and transport codes in combination with the component and subsystem level radiation test data. Previous work by Koontz, et al.1 utilized FLUKA, a Monte Carlo nuclear reaction and transport code, to calculate SEE and single event upset (SEU) rates. This code was then validated against in-flight data for a variety of spacecraft and space flight environments. However, FLUKA has a long run-time (on the order of days). CREME962, an easy to use deterministic code offering short run times, was also compared with FLUKA predictions and in-flight data. CREME96, though fast and easy to use, has not been updated in several years and underestimates secondary particle shower effects in spacecraft structural shielding mass. Thus, this paper will investigate the use of HZETRN 20103, a fast and easy to use deterministic transport code, similar to CREME96, that was developed at NASA Langley Research Center primarily for flight crew ionizing radiation dose assessments. HZETRN 2010 includes updates to address secondary particle shower effects more accurately, and might be used as another tool to verify spacecraft avionics system reliability in space flight SEE environments.

3D Rainbow Particle Tracking Velocimetry

NASA Astrophysics Data System (ADS)

Aguirre-Pablo, Andres A.; Xiong, Jinhui; Idoughi, Ramzi; Aljedaani, Abdulrahman B.; Dun, Xiong; Fu, Qiang; Thoroddsen, Sigurdur T.; Heidrich, Wolfgang

2017-11-01

A single color camera is used to reconstruct a 3D-3C velocity flow field. The camera is used to record the 2D (X,Y) position and colored scattered light intensity (Z) from white polyethylene tracer particles in a flow. The main advantage of using a color camera is the capability of combining different intensity levels for each color channel to obtain more depth levels. The illumination system consists of an LCD projector placed perpendicularly to the camera. Different intensity colored level gradients are projected onto the particles to encode the depth position (Z) information of each particle, benefiting from the possibility of varying the color profiles and projected frequencies up to 60 Hz. Chromatic aberrations and distortions are estimated and corrected using a 3D laser engraved calibration target. The camera-projector system characterization is presented considering size and depth position of the particles. The use of these components reduces dramatically the cost and complexity of traditional 3D-PTV systems.

Hugoniot-based equations of state for two filled EPDM rubbers

NASA Astrophysics Data System (ADS)

Pacheco, A. H.; Dattelbaum, D. M.; Orler, E. B.; Bartram, B. D.; Gustavsen, R. L.

2014-05-01

Particle-filled elastomers are commonly used as engineering components due to their ability to provide structural support via their elastic mechanical response. Even small amounts of particle fillers are known to increase the mechanical strength of elastomers due to polymer-filler interactions. In this work, the shock response of two filled (SiO2 or silica and KevlarTMfillers) ethylene-propylene-diene (EPDM) rubbers were studied using single and two-stage gas gun-driven plate impact experiments. Hugoniot states were determined using standard plate impact methods. Both filled-EPDM elastomers exhibit high compressibility under shock loading and have a response similar to adiprene rubber.

Contribution of bacteria-like particles to PM2.5 aerosol in urban and rural environments

NASA Astrophysics Data System (ADS)

Wolf, R.; El-Haddad, I.; Slowik, J. G.; Dällenbach, K.; Bruns, E.; Vasilescu, J.; Baltensperger, U.; Prévôt, A. S. H.

2017-07-01

We report highly time-resolved estimates of airborne bacteria-like particle concentrations in ambient aerosol using an Aerodyne aerosol mass spectrometer (AMS). AMS measurements with a newly developed PM2.5 and the standard (PM1) aerodynamic lens were performed at an urban background site (Zurich) and at a rural site (Payerne) in Switzerland. Positive matrix factorization using the multilinear engine (ME-2) implementation was used to estimate the contribution of bacteria-like particles to non-refractory organic aerosol. The success of the method was evaluated by a size-resolved analysis of the organic mass and the analysis of single particle mass spectra, which were detected with a light scattering system integrated into the AMS. Use of the PM2.5 aerodynamic lens increased measured bacteria-like concentrations, supporting the analysis method. However, at all sites, the low concentrations of this component suggest that airborne bacteria constitute a minor fraction of non-refractory PM2.5 organic aerosol mass. Estimated average mass concentrations were below 0.1 μg/m3 and relative contributions were lower than 2% at both sites. During rainfall periods, concentrations of the bacteria-like component increased considerably reaching a short-time maximum of approximately 2 μg/m3 at the Payerne site in summer.

Development of a prototype sensor system for ultra-high-speed LDA-PIV

NASA Astrophysics Data System (ADS)

Griffiths, Jennifer A.; Royle, Gary J.; Bohndiek, Sarah E.; Turchetta, Renato; Chen, Daoyi

2008-04-01

Laser Doppler Anemometry (LDA) and Particle Image Velocimetry (PIV) are commonly used in the analysis of particulates in fluid flows. Despite the successes of these techniques, current instrumentation has placed limitations on the size and shape of the particles undergoing measurement, thus restricting the available data for the many industrial processes now utilising nano/micro particles. Data for spherical and irregularly shaped particles down to the order of 0.1 µm is now urgently required. Therefore, an ultra-fast LDA-PIV system is being constructed for the acquisition of this data. A key component of this instrument is the PIV optical detection system. Both the size and speed of the particles under investigation place challenging constraints on the system specifications: magnification is required within the system in order to visualise particles of the size of interest, but this restricts the corresponding field of view in a linearly inverse manner. Thus, for several images of a single particle in a fast fluid flow to be obtained, the image capture rate and sensitivity of the system must be sufficiently high. In order to fulfil the instrumentation criteria, the optical detection system chosen is a high-speed, lensed, digital imaging system based on state-of-the-art CMOS technology - the 'Vanilla' sensor developed by the UK based MI3 consortium. This novel Active Pixel Sensor is capable of high frame rates and sparse readout. When coupled with an image intensifier, it will have single photon detection capabilities. An FPGA based DAQ will allow real-time operation with minimal data transfer.

Wide-field surface plasmon microscopy of nano- and microparticles: features, benchmarking, limitations, and bioanalytical applications

NASA Astrophysics Data System (ADS)

Nizamov, Shavkat; Scherbahn, Vitali; Mirsky, Vladimir M.

2017-05-01

Detection of nano- and micro-particles is an important task for chemical analytics, food industry, biotechnology, environmental monitoring and many other fields of science and industry. For this purpose, a method based on the detection and analysis of minute signals in surface plasmon resonance images due to adsorption of single nanopartciles was developed. This new technology allows one a real-time detection of interaction of single nano- and micro-particles with sensor surface. Adsorption of each nanoparticle leads to characteristic diffraction image whose intensity depends on the size and chemical composition of the particle. The adsorption rate characterizes volume concentration of nano- and micro-particles. Large monitored surface area of sensor enables a high dynamic range of counting and to a correspondingly high dynamic range in concentration scale. Depending on the type of particles and experimental conditions, the detection limit for aqueous samples can be below 1000 particles per microliter. For application of method in complex media, nanoparticle images are discriminated from image perturbations due to matrix components. First, the characteristic SPRM images of nanoparticles (templates) are collected in aqueous suspensions or spiked real samples. Then, the detection of nanoparticles in complex media using template matching is performed. The detection of various NPs in consumer products like cosmetics, mineral water, juices, and wines was shown at sub-ppb level. The method can be applied for ultrasensitive detection and analysis of nano- and micro-particles of biological (bacteria, viruses, endosomes), biotechnological (liposomes, protein nanoparticles for drug delivery) or technical origin.

Urban ambient particle metrics and health: a time-series analysis.

PubMed

Atkinson, Richard W; Fuller, Gary W; Anderson, H Ross; Harrison, Roy M; Armstrong, Ben

2010-07-01

Epidemiologic evidence suggests that exposure to ambient particulate matter is associated with adverse health effects. Little is known, however, about which components of the particulate mixture (size, number, source, toxicity) are most relevant to health. We investigated associations of a range of particle metrics with daily deaths and hospital admissions in London. Daily concentrations of particle mass (PM10, PM2.5, and PM(10-2.5)), measured using gravimetric, tapered-element-oscillating, and filter-dynamic-measurement-system samplers, as well as particle number concentration and particle composition (carbon, sulfate, nitrate and chloride), were collected from a background monitoring station in central London between 2000 and 2005. All-cause and cause-specific deaths and emergency admissions to hospital in London for the same period were also collected. A Poisson regression time-series model was used in the analysis. The results were not consistent across the various outcomes and lags. Particle number concentration was associated with daily mortality and admissions, particularly for cardiovascular diseases lagged 1-day; increases in particle number concentration (10,166 n/cm3) were associated with 2.2% (95% confidence interval = 0.6% to 3.8%) and 0.6% (-0.4% to 1.7%) increases in cardiovascular deaths and admissions, respectively. Secondary pollutants, especially nonprimary PM2.5, nitrate and sulfate, were more important for respiratory outcomes. This study provides some evidence that specific components of the particle mixture for air pollutants may be relevant to specific diseases. Interpretation should be cautious, however, in particular because exposures were based upon data from a single centrally located monitoring site. There is a need for replication with more comprehensive exposure data, both in London and elsewhere.

Single track effects, Biostack and risk assessment

NASA Technical Reports Server (NTRS)

Curtis, S. B.; Chatterjee, A. (Principal Investigator)

1994-01-01

The scientific career of Prof. Bucker has spanned a very exciting period in the fledgling science of Space Radiation Biology. The capability for placing biological objects in space was developed, and the methods for properly packaging, retrieving and analyzing them were worked out. Meaningful results on the effects of radiation were obtained for the first time. In fact, many of the successful techniques and methodologies for handling biological samples were developed in Prof. Bucker's laboratories, as attested by the extensive Biostack program. He was the first to suggest and successfully carry out experiments in space directly aimed at measuring effects of single tracks of high-energy heavy galactic cosmic rays by specifically identifying whether or not the object had been hit by a heavy particle track. Because the "hit" frequencies of heavy galactic cosmic rays to cell nuclei in the bodies of space travelers will be low, it is expected that any effects to humans on the cellular level will be dominated by single-track cell traversals. This includes the most important generally recognized late effect of space radiation exposure: radiation-induced cancer. This paper addresses the single-track nature of the space radiation environment, and points out the importance of single "hits" in the evaluation of radiation risk for long-term missions occurring outside the earth's magnetic field. A short review is made of biological objects found to show increased effects when "hit" by a single heavy charged-particle in space. A brief discussion is given of the most provocative results from the bacterial spore Bacillus subtilis: experimental evidence that tracks can affect biological systems at much larger distances from the trajectory than previously suspected, and that the resultant inactivation cross section in space calculated for this system is very large. When taken at face value, the implication of these results, when compared to those from experiments performed at ground-based accelerators with beams at low energies in the same LET range, is that high-energy particles can exert their influence a surprising distance from their trajectory and the inactivation cross sections are some 20 times larger than expected. Clearly, beams from high-energy heavy-ion accelerators should be used to confirm these results. For those end points that can also be caused by low-LET beams such as high-energy protons, it is important to measure their action cross sections as well. The ratio of the cross sections for a high-LET beam to that of a low-LET beam is an interesting experimental ratio and, we suggest, of more intrinsic interest than the RBE (Relative Biological Effectiveness). It is a measure of the "biological" importance of one particle type relative to another particle type. This ratio will be introduced and given the name RPPE (Relative Per Particle Effectiveness). Values of RPPE have appeared in the literature and will be discussed. A rather well-known value of this quantity (13,520) has been suggested for the RPPE of high-energy iron ions to high-energy protons. This value was suggested by Letaw et al. Nature 330, 709-710 (1987)] we will call it the Letaw limit. It will be discussed in terms of the importance of the heavy-ion component vs light-ion component of the galactic cosmic rays. It is also pointed out, however, that there may be unique effects from single tracks of heavy ions that do not occur from light-ion tracks. For such effects, the concepts of both RBE and RPPE lose their meaning.

Measurements of long-range azimuthal anisotropies and associated Fourier coefficients for p p collisions at s = 5.02 and 13 TeV and p + Pb collisions at s NN = 5.02  TeV with the ATLAS detector

DOE PAGES

Aaboud, M.; Aad, G.; Abbott, B.; ...

2017-08-22

ATLAS measurements of two-particle correlations are presented formore » $$\\sqrt{s}$$ = 5.02 and 13 TeV pp collisions and for $$\\sqrt{s}$$$_ {NN}$$ = 5.02 TeV p + Pb collisions at the LHC. The correlation functions are measured as a function of relative azimuthal angle Δφ, and pseudorapidity separation Δη, using charged particles detected within the pseudorapidity interval |η| < 2.5. Azimuthal modulation in the long-range component of the correlation function, with |Δη| > 2, is studied using a template fitting procedure to remove a "back-to-back" contribution to the correlation function that primarily arises from hard-scattering processes. In addition to the elliptic, cos(2Δφ), modulation observed in a previous measurement, the pp correlation functions exhibit significant cos(3Δφ) and cos(4Δφ) modulation. The Fourier coefficients v n,n associated with the cos(nΔφ) modulation of the correlation functions for n=2-4 are measured as a function of charged-particle multiplicity and charged-particle transverse momentum. The Fourier coefficients are observed to be compatible with cos(nφ) modulation of per-event single-particle azimuthal angle distributions. The single-particle Fourier coefficients v n are measured as a function of charged-particle multiplicity, and charged-particle transverse momentum for n=2-4. The integrated luminosities used in this analysis are, 64 nb -1 for the $$\\sqrt{s}$$ = 13 TeV pp data, 170 nb-1 for the $$\\sqrt{s}$$ = 5.02 TeV pp data, and 28 nb -1 for the $$\\sqrt{s}$$$_ {NN}$$ = 5.02 TeV p+Pb data.« less

Measurements of long-range azimuthal anisotropies and associated Fourier coefficients for p p collisions at √{s }=5.02 and 13 TeV and p +Pb collisions at √{sNN}=5.02 TeV with the ATLAS detector

NASA Astrophysics Data System (ADS)

Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Abouzeid, O. S.; Abraham, N. L.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adachi, S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Ali, B.; Aliev, M.; Alimonti, G.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allen, B. W.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Alshehri, A. A.; Alstaty, M.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amadio, B. T.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antel, C.; Antonelli, M.; Antonov, A.; Antrim, D. J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Armitage, L. J.; Arnaez, O.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Artz, S.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baak, M. A.; Baas, A. E.; Baca, M. J.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Baines, J. T.; Bajic, M.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Balunas, W. K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisits, M.-S.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska-Blenessy, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barranco Navarro, L.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bedognetti, M.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, J. K.; Bell, A. S.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Belyaev, N. L.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez, J.; Benjamin, D. P.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Beringer, J.; Berlendis, S.; Bernard, N. R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertram, I. A.; Bertsche, C.; Bertsche, D.; Besjes, G. J.; Bessidskaia Bylund, O.; Bessner, M.; Besson, N.; Betancourt, C.; Bethani, A.; Bethke, S.; Bevan, A. J.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Biedermann, D.; Bielski, R.; Biesuz, N. V.; Biglietti, M.; Bilbao de Mendizabal, J.; Billoud, T. R. V.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biondi, S.; Bisanz, T.; Bjergaard, D. M.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blue, A.; Blum, W.; Blumenschein, U.; Blunier, S.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Boerner, D.; Bogaerts, J. A.; Bogavac, D.; Bogdanchikov, A. G.; Bohm, C.; Boisvert, V.; Bokan, P.; Bold, T.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Bortfeldt, J.; Bortoletto, D.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Bossio Sola, J. D.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Boutle, S. K.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Breaden Madden, W. D.; Brendlinger, K.; Brennan, A. J.; Brenner, L.; Brenner, R.; Bressler, S.; Bristow, T. M.; Britton, D.; Britzger, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Broughton, J. H.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Bruni, A.; Bruni, G.; Bruni, L. S.; Brunt, Bh; Bruschi, M.; Bruscino, N.; Bryant, P.; Bryngemark, L.; Buanes, T.; Buat, Q.; Buchholz, P.; Buckley, A. G.; Budagov, I. A.; Buehrer, F.; Bugge, M. K.; Bulekov, O.; Bullock, D.; Burckhart, H.; Burdin, S.; Burgard, C. D.; Burger, A. M.; Burghgrave, B.; Burka, K.; Burke, S.; Burmeister, I.; Burr, J. T. P.; Busato, E.; Büscher, D.; Büscher, V.; Bussey, P.; Butler, J. M.; Buttar, C. M.; Butterworth, J. M.; Butti, P.; Buttinger, W.; Buzatu, A.; Buzykaev, A. R.; Cabrera Urbán, S.; Caforio, D.; Cairo, V. M.; Cakir, O.; Calace, N.; Calafiura, P.; Calandri, A.; Calderini, G.; Calfayan, P.; Callea, G.; Caloba, L. P.; Calvente Lopez, S.; Calvet, D.; Calvet, S.; Calvet, T. P.; Camacho Toro, R.; Camarda, S.; Camarri, P.; Cameron, D.; Caminal Armadans, R.; Camincher, C.; Campana, S.; Campanelli, M.; Camplani, A.; Campoverde, A.; Canale, V.; Canepa, A.; Cano Bret, M.; Cantero, J.; Cao, T.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Capua, M.; Carbone, R. M.; Cardarelli, R.; Cardillo, F.; Carli, I.; Carli, T.; Carlino, G.; Carminati, L.; Carney, R. M. D.; Caron, S.; Carquin, E.; Carrillo-Montoya, G. D.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Casolino, M.; Casper, D. W.; Castaneda-Miranda, E.; Castelijn, R.; Castelli, A.; Castillo Gimenez, V.; Castro, N. F.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Caudron, J.; Cavaliere, V.; Cavallaro, E.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Cerda Alberich, L.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cervelli, A.; Cetin, S. A.; Chafaq, A.; Chakraborty, D.; Chan, S. K.; Chan, Y. L.; Chang, P.; Chapman, J. D.; Charlton, D. G.; Chatterjee, A.; Chau, C. C.; Chavez Barajas, C. A.; Che, S.; Cheatham, S.; Chegwidden, A.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, S.; Chen, S.; Chen, X.; Chen, Y.; Cheng, H. C.; Cheng, H. J.; Cheng, Y.; Cheplakov, A.; Cheremushkina, E.; Cherkaoui El Moursli, R.; Chernyatin, V.; Cheu, E.; Chevalier, L.; Chiarella, V.; Chiarelli, G.; Chiodini, G.; Chisholm, A. S.; Chitan, A.; Chizhov, M. V.; Choi, K.; Chomont, A. R.; Chouridou, S.; Chow, B. K. B.; Christodoulou, V.; Chromek-Burckhart, D.; Chudoba, J.; Chuinard, A. J.; Chwastowski, J. J.; Chytka, L.; Ciapetti, G.; Ciftci, A. K.; Cinca, D.; Cindro, V.; Cioara, I. A.; Ciocca, C.; Ciocio, A.; Cirotto, F.; Citron, Z. H.; Citterio, M.; Ciubancan, M.; Clark, A.; Clark, B. L.; Clark, M. R.; Clark, P. J.; Clarke, R. N.; Clement, C.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Colasurdo, L.; Cole, B.; Colijn, A. P.; Collot, J.; Colombo, T.; Conde Muiño, P.; Coniavitis, E.; Connell, S. H.; Connelly, I. A.; Consorti, V.; Constantinescu, S.; Conti, G.; Conventi, F.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cormier, F.; Cormier, K. J. R.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Cottin, G.; Cowan, G.; Cox, B. E.; Cranmer, K.; Crawley, S. J.; Cree, G.; Crépé-Renaudin, S.; Crescioli, F.; Cribbs, W. A.; Crispin Ortuzar, M.; Cristinziani, M.; Croft, V.; Crosetti, G.; Cueto, A.; Cuhadar Donszelmann, T.; Cummings, J.; Curatolo, M.; Cúth, J.; Czirr, H.; Czodrowski, P.; D'Amen, G.; D'Auria, S.; D'Onofrio, M.; da Cunha Sargedas de Sousa, M. J.; da Via, C.; Dabrowski, W.; Dado, T.; Dai, T.; Dale, O.; Dallaire, F.; Dallapiccola, C.; Dam, M.; Dandoy, J. R.; Dang, N. P.; Daniells, A. C.; Dann, N. S.; Danninger, M.; Dano Hoffmann, M.; Dao, V.; Darbo, G.; Darmora, S.; Dassoulas, J.; Dattagupta, A.; Davey, W.; David, C.; Davidek, T.; Davies, M.; Davison, P.; Dawe, E.; Dawson, I.; de, K.; de Asmundis, R.; de Benedetti, A.; de Castro, S.; de Cecco, S.; de Groot, N.; de Jong, P.; de la Torre, H.; de Lorenzi, F.; de Maria, A.; de Pedis, D.; de Salvo, A.; de Sanctis, U.; de Santo, A.; de Vivie de Regie, J. B.; Dearnaley, W. J.; Debbe, R.; Debenedetti, C.; Dedovich, D. V.; Dehghanian, N.; Deigaard, I.; Del Gaudio, M.; Del Peso, J.; Del Prete, T.; Delgove, D.; Deliot, F.; Delitzsch, C. M.; Dell'Acqua, A.; Dell'Asta, L.; Dell'Orso, M.; Della Pietra, M.; Della Volpe, D.; Delmastro, M.; Delsart, P. A.; Demarco, D. A.; Demers, S.; Demichev, M.; Demilly, A.; Denisov, S. P.; Denysiuk, D.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Deterre, C.; Dette, K.; Deviveiros, P. O.; Dewhurst, A.; Dhaliwal, S.; di Ciaccio, A.; di Ciaccio, L.; di Clemente, W. K.; di Donato, C.; di Girolamo, A.; di Girolamo, B.; di Micco, B.; di Nardo, R.; di Petrillo, K. F.; di Simone, A.; di Sipio, R.; di Valentino, D.; Diaconu, C.; Diamond, M.; Dias, F. A.; Diaz, M. A.; Diehl, E. B.; Dietrich, J.; Díez Cornell, S.; Dimitrievska, A.; Dingfelder, J.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Djuvsland, J. I.; Do Vale, M. A. B.; Dobos, D.; Dobre, M.; Doglioni, C.; Dolejsi, J.; Dolezal, Z.; Donadelli, M.; Donati, S.; Dondero, P.; Donini, J.; Dopke, J.; Doria, A.; Dova, M. T.; Doyle, A. 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U.; Mlynarikova, M.; Moa, T.; Mochizuki, K.; Mogg, P.; Mohapatra, S.; Molander, S.; Moles-Valls, R.; Monden, R.; Mondragon, M. C.; Mönig, K.; Monk, J.; Monnier, E.; Montalbano, A.; Montejo Berlingen, J.; Monticelli, F.; Monzani, S.; Moore, R. W.; Morange, N.; Moreno, D.; Moreno Llácer, M.; Morettini, P.; Morgenstern, S.; Mori, D.; Mori, T.; Morii, M.; Morinaga, M.; Morisbak, V.; Moritz, S.; Morley, A. K.; Mornacchi, G.; Morris, J. D.; Mortensen, S. S.; Morvaj, L.; Moschovakos, P.; Mosidze, M.; Moss, H. J.; Moss, J.; Motohashi, K.; Mount, R.; Mountricha, E.; Moyse, E. J. W.; Muanza, S.; Mudd, R. D.; Mueller, F.; Mueller, J.; Mueller, R. S. P.; Mueller, T.; Muenstermann, D.; Mullen, P.; Mullier, G. A.; Munoz Sanchez, F. J.; Murillo Quijada, J. A.; Murray, W. J.; Musheghyan, H.; Muškinja, M.; Myagkov, A. G.; Myska, M.; Nachman, B. P.; Nackenhorst, O.; Nagai, K.; Nagai, R.; Nagano, K.; Nagasaka, Y.; Nagata, K.; Nagel, M.; Nagy, E.; Nairz, A. M.; Nakahama, Y.; Nakamura, K.; Nakamura, T.; Nakano, I.; Naranjo Garcia, R. F.; Narayan, R.; Narrias Villar, D. I.; Naryshkin, I.; Naumann, T.; Navarro, G.; Nayyar, R.; Neal, H. A.; Nechaeva, P. Yu.; Neep, T. J.; Negri, A.; Negrini, M.; Nektarijevic, S.; Nellist, C.; Nelson, A.; Nemecek, S.; Nemethy, P.; Nepomuceno, A. A.; Nessi, M.; Neubauer, M. S.; Neumann, M.; Neves, R. M.; Nevski, P.; Newman, P. R.; Nguyen, D. H.; Nguyen Manh, T.; Nickerson, R. B.; Nicolaidou, R.; Nielsen, J.; Nikolaenko, V.; Nikolic-Audit, I.; Nikolopoulos, K.; Nilsen, J. K.; Nilsson, P.; Ninomiya, Y.; Nisati, A.; Nisius, R.; Nobe, T.; Nomachi, M.; Nomidis, I.; Nooney, T.; Norberg, S.; Nordberg, M.; Norjoharuddeen, N.; Novgorodova, O.; Nowak, S.; Nozaki, M.; Nozka, L.; Ntekas, K.; Nurse, E.; Nuti, F.; O'Grady, F.; O'Neil, D. C.; O'Rourke, A. A.; O'Shea, V.; Oakham, F. G.; Oberlack, H.; Obermann, T.; Ocariz, J.; Ochi, A.; Ochoa, I.; Ochoa-Ricoux, J. P.; Oda, S.; Odaka, S.; Ogren, H.; Oh, A.; Oh, S. H.; Ohm, C. C.; Ohman, H.; Oide, H.; Okawa, H.; Okumura, Y.; Okuyama, T.; Olariu, A.; Oleiro Seabra, L. F.; Olivares Pino, S. A.; Oliveira Damazio, D.; Olszewski, A.; Olszowska, J.; Onofre, A.; Onogi, K.; Onyisi, P. U. E.; Oreglia, M. J.; Oren, Y.; Orestano, D.; Orlando, N.; Orr, R. S.; Osculati, B.; Ospanov, R.; Otero Y Garzon, G.; Otono, H.; Ouchrif, M.; Ould-Saada, F.; Ouraou, A.; Oussoren, K. P.; Ouyang, Q.; Owen, M.; Owen, R. E.; Ozcan, V. E.; Ozturk, N.; Pachal, K.; Pacheco Pages, A.; Pacheco Rodriguez, L.; Padilla Aranda, C.; Pagáčová, M.; Pagan Griso, S.; Paganini, M.; Paige, F.; Pais, P.; Pajchel, K.; Palacino, G.; Palazzo, S.; Palestini, S.; Palka, M.; Pallin, D.; Panagiotopoulou, E. St.; Pandini, C. E.; Panduro Vazquez, J. G.; Pani, P.; Panitkin, S.; Pantea, D.; Paolozzi, L.; Papadopoulou, Th. D.; Papageorgiou, K.; Paramonov, A.; Paredes Hernandez, D.; Parker, A. J.; Parker, M. A.; Parker, K. A.; Parodi, F.; Parsons, J. A.; Parzefall, U.; Pascuzzi, V. R.; Pasqualucci, E.; Passaggio, S.; Pastore, Fr.; Pásztor, G.; Pataraia, S.; Pater, J. R.; Pauly, T.; Pearce, J.; Pearson, B.; Pedersen, L. E.; Pedersen, M.; Pedraza Lopez, S.; Pedro, R.; Peleganchuk, S. V.; Penc, O.; Peng, C.; Peng, H.; Penwell, J.; Peralva, B. S.; Perego, M. M.; Perepelitsa, D. V.; Perez Codina, E.; Perini, L.; Pernegger, H.; Perrella, S.; Peschke, R.; Peshekhonov, V. D.; Peters, K.; Peters, R. F. Y.; Petersen, B. A.; Petersen, T. C.; Petit, E.; Petridis, A.; Petridou, C.; Petroff, P.; Petrolo, E.; Petrov, M.; Petrucci, F.; Pettersson, N. E.; Peyaud, A.; Pezoa, R.; Phillips, P. W.; Piacquadio, G.; Pianori, E.; Picazio, A.; Piccaro, E.; Piccinini, M.; Pickering, M. A.; Piegaia, R.; Pilcher, J. E.; Pilkington, A. D.; Pin, A. W. J.; Pinamonti, M.; Pinfold, J. L.; Pingel, A.; Pires, S.; Pirumov, H.; Pitt, M.; Plazak, L.; Pleier, M.-A.; Pleskot, V.; Plotnikova, E.; Pluth, D.; Poettgen, R.; Poggioli, L.; Pohl, D.; Polesello, G.; Poley, A.; Policicchio, A.; Polifka, R.; Polini, A.; Pollard, C. S.; Polychronakos, V.; Pommès, K.; Pontecorvo, L.; Pope, B. G.; Popeneciu, G. A.; Poppleton, A.; Pospisil, S.; Potamianos, K.; Potrap, I. N.; Potter, C. J.; Potter, C. T.; Poulard, G.; Poveda, J.; Pozdnyakov, V.; Pozo Astigarraga, M. E.; Pralavorio, P.; Pranko, A.; Prell, S.; Price, D.; Price, L. E.; Primavera, M.; Prince, S.; Prokofiev, K.; Prokoshin, F.; Protopopescu, S.; Proudfoot, J.; Przybycien, M.; Puddu, D.; Purohit, M.; Puzo, P.; Qian, J.; Qin, G.; Qin, Y.; Quadt, A.; Quayle, W. B.; Queitsch-Maitland, M.; Quilty, D.; Raddum, S.; Radeka, V.; Radescu, V.; Radhakrishnan, S. K.; Radloff, P.; Rados, P.; Ragusa, F.; Rahal, G.; Raine, J. A.; Rajagopalan, S.; Rammensee, M.; Rangel-Smith, C.; Ratti, M. G.; Rauch, D. M.; Rauscher, F.; Rave, S.; Ravenscroft, T.; Ravinovich, I.; Raymond, M.; Read, A. L.; Readioff, N. P.; Reale, M.; Rebuzzi, D. M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reed, R. G.; Reeves, K.; Rehnisch, L.; Reichert, J.; Reiss, A.; Rembser, C.; Ren, H.; Rescigno, M.; Resconi, S.; Rezanova, O. L.; Reznicek, P.; Rezvani, R.; Richter, R.; Richter, S.; Richter-Was, E.; Ricken, O.; Ridel, M.; Rieck, P.; Riegel, C. J.; Rieger, J.; Rifki, O.; Rijssenbeek, M.; Rimoldi, A.; Rimoldi, M.; Rinaldi, L.; Ristić, B.; Ritsch, E.; Riu, I.; Rizatdinova, F.; Rizvi, E.; Rizzi, C.; Robertson, S. H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, J. E. M.; Robson, A.; Roda, C.; Rodina, Y.; Rodriguez Perez, A.; Rodriguez Rodriguez, D.; Roe, S.; Rogan, C. S.; Røhne, O.; Roloff, J.; Romaniouk, A.; Romano, M.; Romano Saez, S. M.; Romero Adam, E.; Rompotis, N.; Ronzani, M.; Roos, L.; Ros, E.; Rosati, S.; Rosbach, K.; Rose, P.; Rosien, N.-A.; Rossetti, V.; Rossi, E.; Rossi, L. P.; Rosten, J. H. N.; Rosten, R.; Rotaru, M.; Roth, I.; Rothberg, J.; Rousseau, D.; Rozanov, A.; Rozen, Y.; Ruan, X.; Rubbo, F.; Rudolph, M. S.; Rühr, F.; Ruiz-Martinez, A.; Rurikova, Z.; Rusakovich, N. A.; Ruschke, A.; Russell, H. L.; Rutherfoord, J. P.; Ruthmann, N.; Ryabov, Y. F.; Rybar, M.; Rybkin, G.; Ryu, S.; Ryzhov, A.; Rzehorz, G. F.; Saavedra, A. F.; Sabato, G.; Sacerdoti, S.; Sadrozinski, H. F.-W.; Sadykov, R.; Safai Tehrani, F.; Saha, P.; Sahinsoy, M.; Saimpert, M.; Saito, T.; Sakamoto, H.; Sakurai, Y.; Salamanna, G.; Salamon, A.; Salazar Loyola, J. E.; Salek, D.; Sales de Bruin, P. H.; Salihagic, D.; Salnikov, A.; Salt, J.; Salvatore, D.; Salvatore, F.; Salvucci, A.; Salzburger, A.; Sammel, D.; Sampsonidis, D.; Sánchez, J.; Sanchez Martinez, V.; Sanchez Pineda, A.; Sandaker, H.; Sandbach, R. L.; Sandhoff, M.; Sandoval, C.; Sankey, D. P. C.; Sannino, M.; Sansoni, A.; Santoni, C.; Santonico, R.; Santos, H.; Santoyo Castillo, I.; Sapp, K.; Sapronov, A.; Saraiva, J. G.; Sarrazin, B.; Sasaki, O.; Sato, K.; Sauvan, E.; Savage, G.; Savard, P.; Savic, N.; Sawyer, C.; Sawyer, L.; Saxon, J.; Sbarra, C.; Sbrizzi, A.; Scanlon, T.; Scannicchio, D. A.; Scarcella, M.; Scarfone, V.; Schaarschmidt, J.; Schacht, P.; Schachtner, B. M.; Schaefer, D.; Schaefer, L.; Schaefer, R.; Schaeffer, J.; Schaepe, S.; Schaetzel, S.; Schäfer, U.; Schaffer, A. C.; Schaile, D.; Schamberger, R. D.; Scharf, V.; Schegelsky, V. A.; Scheirich, D.; Schernau, M.; Schiavi, C.; Schier, S.; Schillo, C.; Schioppa, M.; Schlenker, S.; Schmidt-Sommerfeld, K. R.; Schmieden, K.; Schmitt, C.; Schmitt, S.; Schmitz, S.; Schneider, B.; Schnoor, U.; Schoeffel, L.; Schoening, A.; Schoenrock, B. D.; Schopf, E.; Schott, M.; Schouwenberg, J. F. P.; Schovancova, J.; Schramm, S.; Schreyer, M.; Schuh, N.; Schulte, A.; Schultens, M. J.; Schultz-Coulon, H.-C.; Schulz, H.; Schumacher, M.; Schumm, B. A.; Schune, Ph.; Schwartzman, A.; Schwarz, T. A.; Schweiger, H.; Schwemling, Ph.; Schwienhorst, R.; Schwindling, J.; Schwindt, T.; Sciolla, G.; Scuri, F.; Scutti, F.; Searcy, J.; Seema, P.; Seidel, S. C.; Seiden, A.; Seifert, F.; Seixas, J. M.; Sekhniaidze, G.; Sekhon, K.; Sekula, S. J.; Seliverstov, D. M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Serkin, L.; Sessa, M.; Seuster, R.; Severini, H.; Sfiligoj, T.; Sforza, F.; Sfyrla, A.; Shabalina, E.; Shaikh, N. W.; Shan, L. Y.; Shang, R.; Shank, J. T.; Shapiro, M.; Shatalov, P. B.; Shaw, K.; Shaw, S. M.; Shcherbakova, A.; Shehu, C. Y.; Sherwood, P.; Shi, L.; Shimizu, S.; Shimmin, C. O.; Shimojima, M.; Shirabe, S.; Shiyakova, M.; Shmeleva, A.; Shoaleh Saadi, D.; Shochet, M. J.; Shojaii, S.; Shope, D. R.; Shrestha, S.; Shulga, E.; Shupe, M. A.; Sicho, P.; Sickles, A. M.; Sidebo, P. E.; Sideras Haddad, E.; Sidiropoulou, O.; Sidorov, D.; Sidoti, A.; Siegert, F.; Sijacki, Dj.; Silva, J.; Silverstein, S. B.; Simak, V.; Simic, Lj.; Simion, S.; Simioni, E.; Simmons, B.; Simon, D.; Simon, M.; Sinervo, P.; Sinev, N. B.; Sioli, M.; Siragusa, G.; Sivoklokov, S. Yu.; Sjölin, J.; Skinner, M. B.; Skottowe, H. P.; Skubic, P.; Slater, M.; Slavicek, T.; Slawinska, M.; Sliwa, K.; Slovak, R.; Smakhtin, V.; Smart, B. H.; Smestad, L.; Smiesko, J.; Smirnov, S. Yu.; Smirnov, Y.; Smirnova, L. N.; Smirnova, O.; Smith, J. W.; Smith, M. N. K.; Smith, R. W.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snyder, I. M.; Snyder, S.; Sobie, R.; Socher, F.; Soffer, A.; Soh, D. A.; Sokhrannyi, G.; Solans Sanchez, C. A.; Solar, M.; Soldatov, E. Yu.; Soldevila, U.; Solodkov, A. A.; Soloshenko, A.; Solovyanov, O. V.; Solovyev, V.; Sommer, P.; Son, H.; Song, H. Y.; Sood, A.; Sopczak, A.; Sopko, V.; Sorin, V.; Sosa, D.; Sotiropoulou, C. L.; Soualah, R.; Soukharev, A. M.; South, D.; Sowden, B. C.; Spagnolo, S.; Spalla, M.; Spangenberg, M.; Spanò, F.; Sperlich, D.; Spettel, F.; Spighi, R.; Spigo, G.; Spiller, L. A.; Spousta, M.; St. Denis, R. D.; Stabile, A.; Stamen, R.; Stamm, S.; Stanecka, E.; Stanek, R. W.; Stanescu, C.; Stanescu-Bellu, M.; Stanitzki, M. M.; Stapnes, S.; Starchenko, E. A.; Stark, G. H.; Stark, J.; Staroba, P.; Starovoitov, P.; Stärz, S.; Staszewski, R.; Steinberg, P.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stewart, G. A.; Stillings, J. A.; Stockton, M. C.; Stoebe, M.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Stramaglia, M. E.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Strubig, A.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Suchek, S.; Sugaya, Y.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, S.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Suster, C. J. E.; Sutton, M. R.; Suzuki, S.; Svatos, M.; Swiatlowski, M.; Swift, S. P.; Sykora, I.; Sykora, T.; Ta, D.; Tackmann, K.; Taenzer, J.; Taffard, A.; Tafirout, R.; Taiblum, N.; Takai, H.; Takashima, R.; Takeshita, T.; Takubo, Y.; Talby, M.; Talyshev, A. A.; Tanaka, J.; Tanaka, M.; Tanaka, R.; Tanaka, S.; Tanioka, R.; Tannenwald, B. B.; Tapia Araya, S.; Tapprogge, S.; Tarem, S.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tashiro, T.; Tassi, E.; Tavares Delgado, A.; Tayalati, Y.; Taylor, A. C.; Taylor, G. N.; Taylor, P. T. E.; Taylor, W.; Teischinger, F. A.; Teixeira-Dias, P.; Temming, K. K.; Temple, D.; Ten Kate, H.; Teng, P. K.; Teoh, J. J.; Tepel, F.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Theveneaux-Pelzer, T.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, P. D.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Tibbetts, M. J.; Ticse Torres, R. E.; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tipton, P.; Tisserant, S.; Todome, K.; Todorov, T.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tolley, E.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Tong, B.; Tornambe, P.; Torrence, E.; Torres, H.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Trefzger, T.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trocmé, B.; Trofymov, A.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; Truong, L.; Trzebinski, M.; Trzupek, A.; Tseng, J. C.-L.; Tsiareshka, P. V.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsui, K. M.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tu, Y.; Tudorache, A.; Tudorache, V.; Tulbure, T. T.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turgeman, D.; Turk Cakir, I.; Turra, R.; Tuts, P. M.; Ucchielli, G.; Ueda, I.; Ughetto, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usui, J.; Vacavant, L.; Vacek, V.; Vachon, B.; Valderanis, C.; Valdes Santurio, E.; Valencic, N.; Valentinetti, S.; Valero, A.; Valery, L.; Valkar, S.; Valls Ferrer, J. A.; van den Wollenberg, W.; van der Deijl, P. C.; van der Graaf, H.; van Eldik, N.; van Gemmeren, P.; van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vanguri, R.; Vaniachine, A.; Vankov, P.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vasquez, J. G.; Vasquez, G. A.; Vazeille, F.; Vazquez Schroeder, T.; Veatch, J.; Veeraraghavan, V.; Veloce, L. M.; Veloso, F.; Veneziano, S.; Ventura, A.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Viazlo, O.; Vichou, I.; Vickey, T.; Vickey Boeriu, O. E.; Viehhauser, G. H. A.; Viel, S.; Vigani, L.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vittori, C.; Vivarelli, I.; Vlachos, S.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wallangen, V.; Wang, C.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, R.; Wang, S. M.; Wang, T.; Wang, W.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Washbrook, A.; Watkins, P. M.; Watson, A. T.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Weber, S. A.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M. D.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; Whallon, N. L.; Wharton, A. M.; White, A.; White, M. J.; White, R.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilk, F.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winston, O. J.; Winter, B. T.; Wittgen, M.; Wolf, T. M. H.; Wolff, R.; Wolter, M. W.; Wolters, H.; Worm, S. D.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xi, Z.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yamaguchi, D.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yang, Z.; Yao, W.-M.; Yap, Y. C.; Yasu, Y.; Yatsenko, E.; Yau Wong, K. H.; Ye, J.; Ye, S.; Yeletskikh, I.; Yildirim, E.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yuen, S. P. Y.; Yusuff, I.; Zabinski, B.; Zaidan, R.; Zaitsev, A. M.; Zakharchuk, N.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanello, L.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zeng, J. C.; Zeng, Q.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, G.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, L.; Zhang, M.; Zhang, R.; Zhang, R.; Zhang, X.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, L.; Zhou, M.; Zhou, M.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; Zur Nedden, M.; Zwalinski, L.; Atlas Collaboration

2017-08-01

ATLAS measurements of two-particle correlations are presented for √{s }=5.02 and 13 TeV p p collisions and for √{sNN}=5.02 TeV p +Pb collisions at the LHC. The correlation functions are measured as a function of relative azimuthal angle Δ ϕ , and pseudorapidity separation Δ η , using charged particles detected within the pseudorapidity interval |η |<2.5 . Azimuthal modulation in the long-range component of the correlation function, with |Δ η |>2 , is studied using a template fitting procedure to remove a "back-to-back" contribution to the correlation function that primarily arises from hard-scattering processes. In addition to the elliptic, cos (2 Δ ϕ ) , modulation observed in a previous measurement, the p p correlation functions exhibit significant cos (3 Δ ϕ ) and cos (4 Δ ϕ ) modulation. The Fourier coefficients vn ,n associated with the cos (n Δ ϕ ) modulation of the correlation functions for n =2 -4 are measured as a function of charged-particle multiplicity and charged-particle transverse momentum. The Fourier coefficients are observed to be compatible with cos (n ϕ ) modulation of per-event single-particle azimuthal angle distributions. The single-particle Fourier coefficients vn are measured as a function of charged-particle multiplicity, and charged-particle transverse momentum for n =2 -4 . The integrated luminosities used in this analysis are, 64 nb-1 for the √{s }=13 TeV p p data, 170 nb-1 for the √{s }=5.02 TeV p p data, and 28 nb-1 for the √{sNN}=5.02 TeV p +Pb data.

Measurements of long-range azimuthal anisotropies and associated Fourier coefficients for p p collisions at s = 5.02 and 13 TeV and p + Pb collisions at s NN = 5.02  TeV with the ATLAS detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aaboud, M.; Aad, G.; Abbott, B.

ATLAS measurements of two-particle correlations are presented formore » $$\\sqrt{s}$$ = 5.02 and 13 TeV pp collisions and for $$\\sqrt{s}$$$_ {NN}$$ = 5.02 TeV p + Pb collisions at the LHC. The correlation functions are measured as a function of relative azimuthal angle Δφ, and pseudorapidity separation Δη, using charged particles detected within the pseudorapidity interval |η| < 2.5. Azimuthal modulation in the long-range component of the correlation function, with |Δη| > 2, is studied using a template fitting procedure to remove a "back-to-back" contribution to the correlation function that primarily arises from hard-scattering processes. In addition to the elliptic, cos(2Δφ), modulation observed in a previous measurement, the pp correlation functions exhibit significant cos(3Δφ) and cos(4Δφ) modulation. The Fourier coefficients v n,n associated with the cos(nΔφ) modulation of the correlation functions for n=2-4 are measured as a function of charged-particle multiplicity and charged-particle transverse momentum. The Fourier coefficients are observed to be compatible with cos(nφ) modulation of per-event single-particle azimuthal angle distributions. The single-particle Fourier coefficients v n are measured as a function of charged-particle multiplicity, and charged-particle transverse momentum for n=2-4. The integrated luminosities used in this analysis are, 64 nb -1 for the $$\\sqrt{s}$$ = 13 TeV pp data, 170 nb-1 for the $$\\sqrt{s}$$ = 5.02 TeV pp data, and 28 nb -1 for the $$\\sqrt{s}$$$_ {NN}$$ = 5.02 TeV p+Pb data.« less

Measuring molecular motions inside single cells with improved analysis of single-particle trajectories

NASA Astrophysics Data System (ADS)

Rowland, David J.; Biteen, Julie S.

2017-04-01

Single-molecule super-resolution imaging and tracking can measure molecular motions inside living cells on the scale of the molecules themselves. Diffusion in biological systems commonly exhibits multiple modes of motion, which can be effectively quantified by fitting the cumulative probability distribution of the squared step sizes in a two-step fitting process. Here we combine this two-step fit into a single least-squares minimization; this new method vastly reduces the total number of fitting parameters and increases the precision with which diffusion may be measured. We demonstrate this Global Fit approach on a simulated two-component system as well as on a mixture of diffusing 80 nm and 200 nm gold spheres to show improvements in fitting robustness and localization precision compared to the traditional Local Fit algorithm.

Urban organic aerosols measured by single particle mass spectrometry in the megacity of London

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Harrison, R. M.

2011-02-01

During the month of October 2006, as part of the REPARTEE-I experiment (Regent's Park and Tower Environmental Experiment) an Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) was deployed at an urban background location in the city of London, UK. Fifteen particle types were classified, some of which were accompanied by Aerosol Mass Spectrometer (AMS) quantitative aerosol mass loading measurements (Dall'Osto et al., 2009a, b). In this manuscript the origins and properties of four particle types associated with locally generated aerosols, independent of the air mass type advected into London, are examined. One particle type, originating from lubricating oil (referred to as Ca-EC), was associated with morning rush hour traffic emissions. A second particle type, composed of both inorganic and organic species (called Na-EC-OC), was found enhanced in particle number concentration during evening time periods, and is likely to originate from a source operating at this time of day, or more probably from condensation of semi-volatile species, and contains both primary and secondary components. A third class, internally mixed with organic carbon and sulphate (called OC), was found to spike both in the morning and evenings. The fourth class (SOA-PAH) exhibited maximum frequency during the warmest part of the day, and a number of factors point towards secondary production from traffic-related volatile aromatic compounds. Single particle mass spectra of this particle type showed an oxidized polycyclic aromatic compound signature. Finally, a comparison of ATOFMS particle class data is made with factors obtained by Positive Matrix Factorization from AMS data.. Both the Ca-EC and OC particle types correlate with the AMS HOA primary organic fraction (R2 = 0.65 and 0.50 respectively), and Na-EC-OC, but not SOA-PAH, which correlates weakly with the AMS OOA secondary organic aerosol factor (R2 = 0.35). A detailed analysis was conducted to identify ATOFMS particle type(s) representative of the AMS COA cooking aerosol factor, but no convincing associations were found.

Non-Destructive Inspection Methods for Propulsion Systems and Components

DTIC Science & Technology

1979-04-01

debris on a microfilter, followed by X-ray examination of the deposits and atomic absorption analysis of the deposits dissolved in hydrochloric acid ...thickness. A single naphthenic mineral oil was used for all tests in a once through system to avoid particle contamination. It was found that: the total...Superalliage. Alliage nickel. Acier inoxydable. Mesure expdrimentale. Transformation phase. Oxydation . Carbonisation. Aube turbine. Ddtection ddfaut. Contr6le

Pulmonary epithelial response in the rat lung to instilled Montserrat respirable dusts and their major mineral components

PubMed Central

Housley, D; Berube, K; Jones, T; Anderson, S; Pooley, F; Richards, R

2002-01-01

Background: The Soufriere Hills, a stratovolcano on Montserrat, started erupting in July 1995, producing volcanic ash, both from dome collapse pyroclastic flows and phreatic explosions. The eruptions/ash resuspension result in high concentrations of suspended particulate matter in the atmosphere, which includes cristobalite, a mineral implicated in respiratory disorders. Aims: To conduct toxicological studies on characterised samples of ash, together with major components of the dust mixture (anorthite, cristobalite), and a bioreactive mineral control (DQ12 quartz). Methods: Rats were challenged with a single mass (1 mg) dose of particles via intratracheal instillation and groups sacrificed at one, three, and nine weeks. Acute bioreactivity of the particles was assessed by increases in lung permeability and inflammation, changes in epithelial cell markers, and increase in the size of bronchothoracic lymph nodes. Results: Data indicated that respirable ash derived from pyroclastic flows (20.1% cristobalite) or phreatic explosion (8.6% cristobalite) had minimal bioreactivity in the lung. Anorthite showed low bioreactivity, in contrast to pure cristobalite, which showed progressive increases in lung damage. Conclusion: Results suggests that either the percentage mass of cristobalite particles present in Montserrat ash was not sufficient as a catalyst in the lung environment, or its surface reactivity was masked by the non-reactive volcanic glass components during the process of ash formation. PMID:12107295

Snow particles extracted from X-ray computed microtomography imagery and their single-scattering properties

NASA Astrophysics Data System (ADS)

Ishimoto, Hiroshi; Adachi, Satoru; Yamaguchi, Satoru; Tanikawa, Tomonori; Aoki, Teruo; Masuda, Kazuhiko

2018-04-01

Sizes and shapes of snow particles were determined from X-ray computed microtomography (micro-CT) images, and their single-scattering properties were calculated at visible and near-infrared wavelengths using a Geometrical Optics Method (GOM). We analyzed seven snow samples including fresh and aged artificial snow and natural snow obtained from field samples. Individual snow particles were numerically extracted, and the shape of each snow particle was defined by applying a rendering method. The size distribution and specific surface area distribution were estimated from the geometrical properties of the snow particles, and an effective particle radius was derived for each snow sample. The GOM calculations at wavelengths of 0.532 and 1.242 μm revealed that the realistic snow particles had similar scattering phase functions as those of previously modeled irregular shaped particles. Furthermore, distinct dendritic particles had a characteristic scattering phase function and asymmetry factor. The single-scattering properties of particles of effective radius reff were compared with the size-averaged single-scattering properties. We found that the particles of reff could be used as representative particles for calculating the average single-scattering properties of the snow. Furthermore, the single-scattering properties of the micro-CT particles were compared to those of particle shape models using our current snow retrieval algorithm. For the single-scattering phase function, the results of the micro-CT particles were consistent with those of a conceptual two-shape model. However, the particle size dependence differed for the single-scattering albedo and asymmetry factor.

Brownian motion studies of viscoelastic colloidal gels by rotational single particle tracking

DOE PAGES

Liang, Mengning; Harder, Ross; Robinson, Ian K.

2014-04-14

Colloidal gels have unique properties due to a complex microstructure which forms into an extended network. Although the bulk properties of colloidal gels have been studied, there has been difficulty correlating those properties with individual colloidal dynamics on the microscale due to the very high viscosity and elasticity of the material. We utilize rotational X-ray tracking (RXT) to investigate the rotational motion of component crystalline colloidal particles in a colloidal gel of alumina and decanoic acid. Our investigation has determined that the high elasticity of the bulk is echoed by a high elasticity experienced by individual colloidal particles themselves butmore » also finds an unexpected high degree of rotational diffusion, indicating a large degree of freedom in the rotational motion of individual colloids even within a tightly bound system.« less

Synergistic effects of atmospheric pressure plasma-emitted components on DNA oligomers: a Raman spectroscopic study.

PubMed

Edengeiser, Eugen; Lackmann, Jan-Wilm; Bründermann, Erik; Schneider, Simon; Benedikt, Jan; Bandow, Julia E; Havenith, Martina

2015-11-01

Cold atmospheric-pressure plasmas have become of increasing importance in sterilization processes especially with the growing prevalence of multi-resistant bacteria. Albeit the potential for technological application is obvious, much less is known about the molecular mechanisms underlying bacterial inactivation. X-jet technology separates plasma-generated reactive particles and photons, thus allowing the investigation of their individual and joint effects on DNA. Raman spectroscopy shows that particles and photons cause different modifications in DNA single and double strands. The treatment with the combination of particles and photons does not only result in cumulative, but in synergistic effects. Profilometry confirms that etching is a minor contributor to the observed DNA damage in vitro. Schematics of DNA oligomer treatment with cold atmospheric-pressure plasma. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Coherent diffraction imaging analysis of shape-controlled nanoparticles with focused hard X-ray free-electron laser pulses.

PubMed

Takahashi, Yukio; Suzuki, Akihiro; Zettsu, Nobuyuki; Oroguchi, Tomotaka; Takayama, Yuki; Sekiguchi, Yuki; Kobayashi, Amane; Yamamoto, Masaki; Nakasako, Masayoshi

2013-01-01

We report the first demonstration of the coherent diffraction imaging analysis of nanoparticles using focused hard X-ray free-electron laser pulses, allowing us to analyze the size distribution of particles as well as the electron density projection of individual particles. We measured 1000 single-shot coherent X-ray diffraction patterns of shape-controlled Ag nanocubes and Au/Ag nanoboxes and estimated the edge length from the speckle size of the coherent diffraction patterns. We then reconstructed the two-dimensional electron density projection with sub-10 nm resolution from selected coherent diffraction patterns. This method enables the simultaneous analysis of the size distribution of synthesized nanoparticles and the structures of particles at nanoscale resolution to address correlations between individual structures of components and the statistical properties in heterogeneous systems such as nanoparticles and cells.

Hybrid solar collector using nonimaging optics and photovoltaic components

NASA Astrophysics Data System (ADS)

Winston, Roland; Yablonovitch, Eli; Jiang, Lun; Widyolar, Bennett K.; Abdelhamid, Mahmoud; Scranton, Gregg; Cygan, David; Kozlov, Alexandr

2015-08-01

The project team of University of California at Merced (UC-M), Gas Technology Institute, and Dr. Eli Yablonovitch of University of California at Berkeley developed a novel hybrid concentrated solar photovoltaic thermal (PV/T) collector using nonimaging optics and world record single-junction Gallium arsenide (GaAs) PV components integrated with particle laden gas as thermal transfer and storage media, to simultaneously generate electricity and high temperature dispatchable heat. The collector transforms a parabolic trough, commonly used in CSP plants, into an integrated spectrum-splitting device. This places a spectrum-sensitive topping element on a secondary reflector that is registered to the thermal collection loop. The secondary reflector transmits higher energy photons for PV topping while diverting the remaining lower energy photons to the thermal media, achieving temperatures of around 400°C even under partial utilization of the solar spectrum. The collector uses the spectral selectivity property of Gallium arsenide (GaAs) cells to maximize the exergy output of the system, resulting in an estimated exergy efficiency of 48%. The thermal media is composed of fine particles of high melting point material in an inert gas that increases heat transfer and effectively stores excess heat in hot particles for later on-demand use.

Fluorescence enhancement on silver nanostructures: studies of components of ribosomal translation in vitro

NASA Astrophysics Data System (ADS)

Mandecki, Wlodek; Bharill, Shashank; Borejdo, Julian; Cabral, Diana; Cooperman, Barry S.; Farrell, Ian; Fetter, Linus; Goldman, Emanuel; Gryczynski, Zygmunt; Jakubowski, Hieronim; Liu, Hanqing; Luchowski, Rafal; Matveeva, Evgenia; Pan, Dongli; Qin, Haiou; Tennant, Donald; Gryczynski, Ignacy

2008-02-01

Metallic particles, silver in particular, can significantly enhance the fluorescence of dye molecules in the immediate vicinity (5-20 nm) of the particle. This magnifying effect can be theoretically explained/predicted by considering the change of photonic mode density near the fluorophore due to coupling to the conducting surface. We are using this method to observe fluorescence from a single ribosomal particle in a project aimed at acquiring sequence information from the translating ribosome (NIH's $1000 Genome Initiative). Several quartz slides with silver nanostructures were made using electron beam lithography techniques. The structures were approximately 50 nm high silver tiles measuring 400-700 nm on the side, and were spaced differently over a total area of 1 mm x 1 mm on any given quartz slide. In a preliminary experiment, we coated this surface with the Alexa 647-labeled antibodies and collected single molecule images using the MicroTime 200 (PicoQuant) confocal system. We showed that the fluorescence intensity measured over the silver islands film was more than 100-fold higher than fluorescence from a comparable site on uncoated section of the quartz slide. No noticeable photobleaching was seen. The fluorescence lifetime was very short, about 200 ps or less (this is the resolution limit of the system). The method has great promise for investigations of biologically relevant single molecules.

Intracellular trafficking of silicon particles and logic-embedded vectors

NASA Astrophysics Data System (ADS)

Ferrati, Silvia; Mack, Aaron; Chiappini, Ciro; Liu, Xuewu; Bean, Andrew J.; Ferrari, Mauro; Serda, Rita E.

2010-08-01

Mesoporous silicon particles show great promise for use in drug delivery and imaging applications as carriers for second-stage nanoparticles and higher order particles or therapeutics. Modulation of particle geometry, surface chemistry, and porosity allows silicon particles to be optimized for specific applications such as vascular targeting and avoidance of biological barriers commonly found between the site of drug injection and the final destination. In this study, the intracellular trafficking of unloaded carrier silicon particles and carrier particles loaded with secondary iron oxide nanoparticles was investigated. Following cellular uptake, membrane-encapsulated silicon particles migrated to the perinuclear region of the cell by a microtubule-driven mechanism. Surface charge, shape (spherical and hemispherical) and size (1.6 and 3.2 μm) of the particle did not alter the rate of migration. Maturation of the phagosome was associated with an increase in acidity and acquisition of markers of late endosomes and lysosomes. Cellular uptake of iron oxide nanoparticle-loaded silicon particles resulted in sorting of the particles and trafficking to unique destinations. The silicon carriers remained localized in phagosomes, while the second stage iron oxide nanoparticles were sorted into multi-vesicular bodies that dissociated from the phagosome into novel membrane-bound compartments. Release of iron from the cells may represent exocytosis of iron oxide nanoparticle-loaded vesicles. These results reinforce the concept of multi-functional nanocarriers, in which different particles are able to perform specific tasks, in order to deliver single- or multi-component payloads to specific sub-cellular compartments.Mesoporous silicon particles show great promise for use in drug delivery and imaging applications as carriers for second-stage nanoparticles and higher order particles or therapeutics. Modulation of particle geometry, surface chemistry, and porosity allows silicon particles to be optimized for specific applications such as vascular targeting and avoidance of biological barriers commonly found between the site of drug injection and the final destination. In this study, the intracellular trafficking of unloaded carrier silicon particles and carrier particles loaded with secondary iron oxide nanoparticles was investigated. Following cellular uptake, membrane-encapsulated silicon particles migrated to the perinuclear region of the cell by a microtubule-driven mechanism. Surface charge, shape (spherical and hemispherical) and size (1.6 and 3.2 μm) of the particle did not alter the rate of migration. Maturation of the phagosome was associated with an increase in acidity and acquisition of markers of late endosomes and lysosomes. Cellular uptake of iron oxide nanoparticle-loaded silicon particles resulted in sorting of the particles and trafficking to unique destinations. The silicon carriers remained localized in phagosomes, while the second stage iron oxide nanoparticles were sorted into multi-vesicular bodies that dissociated from the phagosome into novel membrane-bound compartments. Release of iron from the cells may represent exocytosis of iron oxide nanoparticle-loaded vesicles. These results reinforce the concept of multi-functional nanocarriers, in which different particles are able to perform specific tasks, in order to deliver single- or multi-component payloads to specific sub-cellular compartments. Electronic supplementary information (ESI) available: Confocal microscopy image showing internalized negative particles, and movie of the intracellular migration of silicon particles. See DOI: 10.1039/c0nr00227e

Light-induced cross transport phenomena in a single-component gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chermyaninov, I. V.; Chernyak, V. G., E-mail: Vladimir.Chernyak@usu.ru

2013-07-15

The cross transport processes that occur in a single-component gas in a capillary and are caused by resonance laser radiation and pressure and temperature gradients are studied. An expression for entropy production is derived using a system of kinetic Boltzmann equations in a linear approximation. The kinetic coefficients that determine the transport processes are shown to satisfy the Onsager reciprocal relations at any Knudsen numbers and any character of the elastic interaction of gas particles with the capillary surface. The light-induced baro- and thermoeffects that take place in a closed heat-insulated system in the field of resonance laser radiation aremore » considered. Analytical expressions are obtained for the Onsager coefficients in an almost free-molecular regime. The light-induced pressure and temperature gradients that appear in a closed heat-insulated capillary under typical experimental conditions are numerically estimated.« less

The study of ionization by electron impact of a substance simulating spent nuclear fuel components

NASA Astrophysics Data System (ADS)

Antonov, N. N.; Bochkarev, E. I.; Gavrikov, A. V.; Samokhin, A. A.; Smirnov, V. P.

2015-11-01

Plasma sources of model substances are necessary to solve problems associated with development of the spent nuclear fuel (SNF) plasma separation method. Lead was chosen to simulate kinetic and dynamic properties of the heavy SNF components. In this paper we present the results of a study of a lead vapor discharge with a lead concentration of 1012-1013 cm-3. Ionization was carried out by an electron beam (with energy of up to 500 eV per electron) inside a centimeter gap between planar electrodes. The discharge was numerically modeled using the hydrodynamic and single-particle approximation. Current-voltage characteristics and single ionization efficiency were obtained as functions of the vapors concentration and thermoelectric current. An ion current of hundreds of microamperes at the ionization efficiency near tenths of a percent was experimentally obtained. These results are in good agreement with our model.

Can tokamaks PFC survive a single event of any plasma instabilities?

NASA Astrophysics Data System (ADS)

Hassanein, A.; Sizyuk, V.; Miloshevsky, G.; Sizyuk, T.

2013-07-01

Plasma instability events such as disruptions, edge-localized modes (ELMs), runaway electrons (REs), and vertical displacement events (VDEs) are continued to be serious events and most limiting factors for successful tokamak reactor concept. The plasma-facing components (PFCs), e.g., wall, divertor, and limited surfaces of a tokamak as well as coolant structure materials are subjected to intense particle and heat loads and must maintain a clean and stable surface environment among them and the core/edge plasma. Typical ITER transient events parameters are used for assessing the damage from these four different instability events. HEIGHTS simulation showed that a single event of a disruption, giant ELM, VDE, or RE can cause significant surface erosion (melting and vaporization) damage to PFC, nearby components, and/or structural materials (VDE, RE) melting and possible burnout of coolant tubes that could result in shut down of reactor for extended repair time.

Solar system applications of Mie theory and of radiative transfer of polarized light

NASA Technical Reports Server (NTRS)

Whitehill, L. P.

1972-01-01

A theory of the multiple scattering of polarized light is discussed using the doubling method of van de Hulst. The concept of the Stokes parameters is derived and used to develop the form of the scattering phase matrix of a single particle. The diffuse reflection and transmission matrices of a single scattering plane parallel atmosphere are expressed as a function of the phase matrix, and the symmetry properties of these matrices are examined. Four matrices are required to describe scattering and transmission. The scattering matrix that results from the addition of two identical layers is derived. Using the doubling method, the scattering and transmission matrices of layers of arbitrary optical thickness can be derived. The doubling equations are then rewritten in terms of their Fourier components. Computation time is reduced since each Fourier component doubles independently. Computation time is also reduced through the use of symmetry properties.

Single-cell isolation using a DVD optical pickup

PubMed Central

Kasukurti, A.; Potcoava, M.; Desai, S.A.; Eggleton, C.; Marr, D. W. M.

2011-01-01

A low-cost single-cell isolation system incorporating a digital versatile disc burner (DVD RW) optical pickup has been developed. We show that these readily available modules have the required laser power and focusing optics to provide a steady Gaussian beam capable of optically trapping micron-sized colloids and red blood cells. Utility of the pickup is demonstrated through the non-destructive isolation of such particles in a laminar-flow based microfluidic device that captures and translates single microscale objects across streamlines into designated channel exits. In this, the integrated objective lens focusing coils are used to steer the optical trap across the channel, resulting in the isolation of colloids and red blood cells using a very inexpensive off-the-shelf optical component. PMID:21643294

The Impacts of Dust Storm Particles on Human Lung Cells - an Analysis at the Single Cell Level

NASA Astrophysics Data System (ADS)

Ardon-Dryer, K.; Mock, C.; Reyes, J.; Lahav, G.

2017-12-01

Aerosols particles (Natural and anthropogenic) are a key component of our atmosphere, their presence defines air quality levels and they can affect our health. Small particles penetrate into our lungs and this exposure can cause our lung cells to stress and in some cases leads to the death of the cells and to inflammation. During dust storm events there is an increase in particle concentration, many of them are breathable particles that can penetrate deep into our lungs. Exposure to dust particles can lead to respiratory problems, particularly for people with asthma. Therefore, during and after a dust storm event the number of people who are hospitalized with inflammation and respiratory problems increase. However, the exact mechanism that causes these health problems is still unclear. In this project, we are investigating the impacts that dust storm particles from different sources and of different concentrations (doses) have on human lung cells, performing a new and unique analysis at the single cell level. To accomplish this, each individual lung cell is continuously tracked after being exposed to dust particles. We monitor the behavior of the cell over time, identify the cells time of death and type of death (e.g. cell explosion). With this analysis, we can quantify cell death as a function of dust concertation (doses); to our surprise, an increase in cells death was not observed only as a function of an increase of dust concertation. In addition, we noticed that the way particles come in contact with cells, by sticking to or being engulfed by, and the interaction duration has an effect; cells that interact with dust particles for a longer period died earlier compared to cells with a shorter interaction period. These findings will help us to better understand the health related consequences of exposure to dust storm events and serve as a baseline for when evaluating other aerosol.

Residential indoor and outdoor coarse particles and associated endotoxin exposures

NASA Astrophysics Data System (ADS)

Wheeler, Amanda J.; Dobbin, Nina A.; Lyrette, Ninon; Wallace, Lance; Foto, Mark; Mallick, Ranjeeta; Kearney, Jill; Van Ryswyk, Keith; Gilbert, Nicolas L.; Harrison, Ian; Rispler, Kathleen; Héroux, Marie-Eve

2011-12-01

There is a growing body of evidence demonstrating that coarse particles (PM 10-2.5) have detrimental impacts upon health, especially for respiratory effects. There are limited data available for indoor residential exposures. Some data exist regarding the composition of this PM size fraction with emphasis on crustal elements and biological components. This study includes data from 146 homes sampled in Regina, Saskatchewan (SK) where 5-day integrated concurrent monitoring of indoor and outdoor coarse particles was conducted during the winter and summer of 2007. The coarse particle filters were subsequently analysed for endotoxin content to determine the contribution of this compound. Winter indoor geometric mean concentrations of coarse particles exceeded outdoor concentrations (3.73 μg m -3 vs 2.49 μg m -3; paired t-test p < 0.0001); however the reverse was found in summer (4.34 μg m -3 vs 8.82 μg m -3; paired t-test p < 0.0001). Linear regression indicated that winter predictors of indoor coarse particles were outdoor coarse particles, ventilation and presence of at least two or more occupants. During the summer, increased use of central air conditioning was associated with reduced coarse particles, while smoking and the presence of two or more occupants resulted in increased coarse particles. Endotoxin concentrations (EU μg -1) were lower indoors than outdoors in both seasons. Spatial variability of ambient coarse particles was assessed to determine the suitability of using a single monitoring station within a city to estimate exposure. The coefficients of variation between homes sampled simultaneously and the central monitoring station were calculated (median COV in summer = 15% and winter = 24%) and showed significant variability by week, especially during the summer months, suggesting a single site may be insufficient for characterizing exposure. Future studies should consider daily measurements per home to understand shorter term exposures and day to day variability of these pollutants.

Single, binary and multi-component adsorption of some anions and heavy metals on environmentally friendly Carpobrotus edulis plant.

PubMed

Chiban, Mohamed; Soudani, Amina; Sinan, Fouad; Persin, Michel

2011-02-01

A low-cost adsorbent and environmentally friendly adsorbent from Carpobrotus edulis plant was used for the removal of NO(3)(-), H(2)PO(4)(-), Pb(2+) and Cd(2+) ions from single, binary and multi-component systems. The efficiency of the adsorbent was studied using batch adsorption technique under different experimental conditions by varying parameters such as pH, initial concentration and contact time. In single component systems, the dried C. edulis has the highest affinity for Pb(2+), followed by NO(3)(-), Cd(2+) and H(2)PO(4)(-), with adsorption capacities of 175mg/g, 125mg/g, 28mg/g and 26mg/g, respectively. These results showed that the adsorption of NO(3)(-) and H(2)PO(4)(-) ions from single and binary component systems can be successfully described by Langmuir and Freundlich isotherms. Freundlich adsorption model, showed the best fit to the single and binary experimental adsorption data. These results also indicated that the adsorption yield of Pb(2+) ion was reduced by the presence of Cd(2+) ion in binary metal mixture. The competitive adsorption of NO(3)(-), H(2)PO(4)(-), Pb(2+) and Cd(2+) ions on dried C. edulis plant shows that NO(3)(-) and H(2)PO(4)(-) anions are able to adsorb on different free binding sites and Pb(2+) and Cd(2+) cations are able to adsorb on the same active sites of C. edulis particles. The dried C. edulis was found to be efficient in removing nitrate, phosphate, cadmium and lead from aqueous solution as compared to other adsorbents already used for the removal of these ions. Copyright © 2010 Elsevier B.V. All rights reserved.

Optical properties of non-spherical desert dust particles in the terrestrial infrared - An asymptotic approximation approach

NASA Astrophysics Data System (ADS)

Klüser, Lars; Di Biagio, Claudia; Kleiber, Paul D.; Formenti, Paola; Grassian, Vicki H.

2016-07-01

Optical properties (extinction efficiency, single scattering albedo, asymmetry parameter and scattering phase function) of five different desert dust minerals have been calculated with an asymptotic approximation approach (AAA) for non-spherical particles. The AAA method combines Rayleigh-limit approximations with an asymptotic geometric optics solution in a simple and straightforward formulation. The simulated extinction spectra have been compared with classical Lorenz-Mie calculations as well as with laboratory measurements of dust extinction. This comparison has been done for single minerals and with bulk dust samples collected from desert environments. It is shown that the non-spherical asymptotic approximation improves the spectral extinction pattern, including position of the extinction peaks, compared to the Lorenz-Mie calculations for spherical particles. Squared correlation coefficients from the asymptotic approach range from 0.84 to 0.96 for the mineral components whereas the corresponding numbers for Lorenz-Mie simulations range from 0.54 to 0.85. Moreover the blue shift typically found in Lorenz-Mie results is not present in the AAA simulations. The comparison of spectra simulated with the AAA for different shape assumptions suggests that the differences mainly stem from the assumption of the particle shape and not from the formulation of the method itself. It has been shown that the choice of particle shape strongly impacts the quality of the simulations. Additionally, the comparison of simulated extinction spectra with bulk dust measurements indicates that within airborne dust the composition may be inhomogeneous over the range of dust particle sizes, making the calculation of reliable radiative properties of desert dust even more complex.

Routine single particle CryoEM sample and grid characterization by tomography

PubMed Central

Noble, Alex J; Brasch, Julia; Chase, Jillian; Acharya, Priyamvada; Tan, Yong Zi; Zhang, Zhening; Kim, Laura Y; Scapin, Giovanna; Rapp, Micah; Eng, Edward T; Rice, William J; Cheng, Anchi; Negro, Carl J; Shapiro, Lawrence; Kwong, Peter D; Jeruzalmi, David; des Georges, Amedee; Potter, Clinton S

2018-01-01

Single particle cryo-electron microscopy (cryoEM) is often performed under the assumption that particles are not adsorbed to the air-water interfaces and in thin, vitreous ice. In this study, we performed fiducial-less tomography on over 50 different cryoEM grid/sample preparations to determine the particle distribution within the ice and the overall geometry of the ice in grid holes. Surprisingly, by studying particles in holes in 3D from over 1000 tomograms, we have determined that the vast majority of particles (approximately 90%) are adsorbed to an air-water interface. The implications of this observation are wide-ranging, with potential ramifications regarding protein denaturation, conformational change, and preferred orientation. We also show that fiducial-less cryo-electron tomography on single particle grids may be used to determine ice thickness, optimal single particle collection areas and strategies, particle heterogeneity, and de novo models for template picking and single particle alignment. PMID:29809143

Two-component flux explanation for the high energy neutrino events at IceCube

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Chien-Yi; Dev, P. S. Bhupal; Soni, Amarjit

In understanding the spectral and flavor composition of the astrophysical neutrino flux responsible for the recently observed ultrahigh-energy events at IceCube we see how important both astrophysics and particle physics are. Here, we perform a statistical likelihood analysis to the three-year IceCube data and derive the allowed range of the spectral index and flux normalization for various well-motivated physical flavor compositions at the source. While most of the existing analyses so far assume the flavor composition of the neutrinos at an astrophysical source to be (1:2:0), it seems rather unnatural to assume only one type of source, once we recognizemore » the possibility of at least two physical sources. Bearing this in mind, we entertain the possibility of a two-component source for the analysis of IceCube data. It appears that our two-component hypothesis explains some key features of the data better than a single-component scenario; i.e. it addresses the apparent energy gap between 400 TeV and about 1 PeV and easily accommodates the observed track-to-shower ratio. Given the extreme importance of the flavor composition for the correct interpretation of the underlying astrophysical processes as well as for the ramification for particle physics, this two-component flux should be tested as more data is accumulated.« less

Two-component flux explanation for the high energy neutrino events at IceCube

DOE PAGES

Chen, Chien-Yi; Dev, P. S. Bhupal; Soni, Amarjit

2015-10-01

In understanding the spectral and flavor composition of the astrophysical neutrino flux responsible for the recently observed ultrahigh-energy events at IceCube we see how important both astrophysics and particle physics are. Here, we perform a statistical likelihood analysis to the three-year IceCube data and derive the allowed range of the spectral index and flux normalization for various well-motivated physical flavor compositions at the source. While most of the existing analyses so far assume the flavor composition of the neutrinos at an astrophysical source to be (1:2:0), it seems rather unnatural to assume only one type of source, once we recognizemore » the possibility of at least two physical sources. Bearing this in mind, we entertain the possibility of a two-component source for the analysis of IceCube data. It appears that our two-component hypothesis explains some key features of the data better than a single-component scenario; i.e. it addresses the apparent energy gap between 400 TeV and about 1 PeV and easily accommodates the observed track-to-shower ratio. Given the extreme importance of the flavor composition for the correct interpretation of the underlying astrophysical processes as well as for the ramification for particle physics, this two-component flux should be tested as more data is accumulated.« less

The frequency-dependent response of single aerosol particles to vapour phase oscillations and its application in measuring diffusion coefficients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Preston, Thomas C.; Davies, James F.; Wilson, Kevin R.

A new method for measuring diffusion in the condensed phase of single aerosol particles is proposed and demonstrated. The technique is based on the frequency-dependent response of a binary particle to oscillations in the vapour phase of one of its chemical components. Here, we discuss how this physical situation allows for what would typically be a non-linear boundary value problem to be approximately reduced to a linear boundary value problem. For the case of aqueous aerosol particles, we investigate the accuracy of the closed-form analytical solution to this linear problem through a comparison with the numerical solution of the fullmore » problem. Then, using experimentally measured whispering gallery modes to track the frequency-dependent response of aqueous particles to relative humidity oscillations, we determine diffusion coefficients as a function of water activity. The measured diffusion coefficients are compared to previously reported values found using the two common experiments: (i) the analysis of the sorption/desorption of water from a particle after a step-wise change to the surrounding relative humidity and (ii) the isotopic exchange of water between a particle and the vapour phase. The technique presented here has two main strengths: first, when compared to the sorption/desorption experiment, it does not require the numerical evaluation of a boundary value problem during the fitting process as a closed-form expression is available. Second, when compared to the isotope exchange experiment, it does not require the use of labeled molecules. Therefore, the frequency-dependent experiment retains the advantages of these two commonly used methods but does not suffer from their drawbacks.« less

The frequency-dependent response of single aerosol particles to vapour phase oscillations and its application in measuring diffusion coefficients

DOE PAGES

Preston, Thomas C.; Davies, James F.; Wilson, Kevin R.

2017-01-13

A new method for measuring diffusion in the condensed phase of single aerosol particles is proposed and demonstrated. The technique is based on the frequency-dependent response of a binary particle to oscillations in the vapour phase of one of its chemical components. Here, we discuss how this physical situation allows for what would typically be a non-linear boundary value problem to be approximately reduced to a linear boundary value problem. For the case of aqueous aerosol particles, we investigate the accuracy of the closed-form analytical solution to this linear problem through a comparison with the numerical solution of the fullmore » problem. Then, using experimentally measured whispering gallery modes to track the frequency-dependent response of aqueous particles to relative humidity oscillations, we determine diffusion coefficients as a function of water activity. The measured diffusion coefficients are compared to previously reported values found using the two common experiments: (i) the analysis of the sorption/desorption of water from a particle after a step-wise change to the surrounding relative humidity and (ii) the isotopic exchange of water between a particle and the vapour phase. The technique presented here has two main strengths: first, when compared to the sorption/desorption experiment, it does not require the numerical evaluation of a boundary value problem during the fitting process as a closed-form expression is available. Second, when compared to the isotope exchange experiment, it does not require the use of labeled molecules. Therefore, the frequency-dependent experiment retains the advantages of these two commonly used methods but does not suffer from their drawbacks.« less

Aerosol Airmass Type Mapping Over the Urban Mexico City Region From Space-based Multi-angle Imaging

NASA Technical Reports Server (NTRS)

Patadia, F.; Kahn, R. A.; Limbacher, J. A.; Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.

2013-01-01

Using Multi-angle Imaging SpectroRadiometer (MISR) and sub-orbital measurements from the 2006 INTEX-B/MILAGRO field campaign, in this study we explore MISR's ability to map different aerosol air mass types over the Mexico City metropolitan area. The aerosol air mass distinctions are based on shape, size and single scattering albedo retrievals from the MISR Research Aerosol Retrieval algorithm. In this region, the research algorithm identifies dust-dominated aerosol mixtures based on non-spherical particle shape, whereas spherical biomass burning and urban pollution particles are distinguished by particle size. Two distinct aerosol air mass types based on retrieved particle microphysical properties, and four spatially distributed aerosol air masses, are identified in the MISR data on 6 March 2006. The aerosol air mass type identification results are supported by coincident, airborne high-spectral-resolution lidar (HSRL) measurements. Aerosol optical depth (AOD) gradients are also consistent between the MISR and sub-orbital measurements, but particles having single-scattering albedo of approx. 0.7 at 558 nm must be included in the retrieval algorithm to produce good absolute AOD comparisons over pollution-dominated aerosol air masses. The MISR standard V22 AOD product, at 17.6 km resolution, captures the observed AOD gradients qualitatively, but retrievals at this coarse spatial scale and with limited spherical absorbing particle options underestimate AOD and do not retrieve particle properties adequately over this complex urban region. However, we demonstrate how AOD and aerosol type mapping can be accomplished with MISR data over complex urban regions, provided the retrieval is performed at sufficiently high spatial resolution, and with a rich enough set of aerosol components and mixtures.

Note: Establishing α-particle radiation damage experiments using the Dalton Cumbrian Facility's 5 MV tandem pelletron.

PubMed

Bower, W R; Smith, A D; Pattrick, R A D; Pimblott, S M

2015-04-01

Evaluating the radiation stability of mineral phases is a vital research challenge when assessing the performance of the materials employed in a Geological Disposal Facility for radioactive waste. This report outlines the setup and methodology for efficiently allowing the determination of the dose dependence of damage to a mineral from a single ion irradiated sample. The technique has been deployed using the Dalton Cumbrian Facility's 5 MV tandem pelletron to irradiate a suite of minerals with a controlled α-particle ((4)He(2+)) beam. Such minerals are proxies for near-field clay based buffer material surrounding radioactive canisters, as well as the sorbent components of the host rock.

Note: Establishing α-particle radiation damage experiments using the Dalton Cumbrian Facility's 5 MV tandem pelletron

NASA Astrophysics Data System (ADS)

Bower, W. R.; Smith, A. D.; Pattrick, R. A. D.; Pimblott, S. M.

2015-04-01

Evaluating the radiation stability of mineral phases is a vital research challenge when assessing the performance of the materials employed in a Geological Disposal Facility for radioactive waste. This report outlines the setup and methodology for efficiently allowing the determination of the dose dependence of damage to a mineral from a single ion irradiated sample. The technique has been deployed using the Dalton Cumbrian Facility's 5 MV tandem pelletron to irradiate a suite of minerals with a controlled α-particle (4He2+) beam. Such minerals are proxies for near-field clay based buffer material surrounding radioactive canisters, as well as the sorbent components of the host rock.

Nanoparticle detection using dual-phase interferometry

PubMed Central

Deutsch, Bradley; Beams, Ryan; Novotny, Lukas

2013-01-01

Detection and identification of nanoparticles is of growing interest in atmospheric monitoring, medicine and semiconductor manufacturing. While elastic light scattering with interferometric detection provides good sensitivity to single particles, active optical components prevent scalability realistic sizes for deployment in the field or clinic. Here we report on a simple phase-sensitive nanoparticle detection scheme with no active optical elements. Two measurements are taken simultaneously, allowing amplitude and phase to be decoupled. We demonstrate detection of 25 nm Au particles in liquid in Δt ~ 1 ms with a signal-to-noise ratio of 37. Such performance makes it possible to detect nanoscale contaminants or larger proteins in real time without the need of artificial labeling. PMID:20830181

Contactless microparticle control via ultrahigh frequency needle type single beam acoustic tweezers

NASA Astrophysics Data System (ADS)

Fei, Chunlong; Li, Ying; Zhu, Benpeng; Chiu, Chi Tat; Chen, Zeyu; Li, Di; Yang, Yintang; Kirk Shung, K.; Zhou, Qifa

2016-10-01

This paper reports on contactless microparticle manipulation including single-particle controlled trapping, transportation, and patterning via single beam acoustic radiation forces. As the core component of single beam acoustic tweezers, a needle type ultrasonic transducer was designed and fabricated with center frequency higher than 300 MHz and -6 dB fractional bandwidth as large as 64%. The transducer was built for an f-number close to 1.0, and the desired focal depth was achieved by press-focusing technology. Its lateral resolution was measured to be better than 6.7 μm by scanning a 4 μm tungsten wire target. Tightly focused acoustic beam produced by the transducer was shown to be capable of manipulating individual microspheres as small as 3 μm. "USC" patterning with 15 μm microspheres was demonstrated without affecting nearby microspheres. These promising results may expand the applications in biomedical and biophysical research of single beam acoustic tweezers.

A Hybrid Method for Accelerated Simulation of Coulomb Collisions in a Plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caflisch, R; Wang, C; Dimarco, G

2007-10-09

If the collisional time scale for Coulomb collisions is comparable to the characteristic time scales for a plasma, then simulation of Coulomb collisions may be important for computation of kinetic plasma dynamics. This can be a computational bottleneck because of the large number of simulated particles and collisions (or phase-space resolution requirements in continuum algorithms), as well as the wide range of collision rates over the velocity distribution function. This paper considers Monte Carlo simulation of Coulomb collisions using the binary collision models of Takizuka & Abe and Nanbu. It presents a hybrid method for accelerating the computation of Coulombmore » collisions. The hybrid method represents the velocity distribution function as a combination of a thermal component (a Maxwellian distribution) and a kinetic component (a set of discrete particles). Collisions between particles from the thermal component preserve the Maxwellian; collisions between particles from the kinetic component are performed using the method of or Nanbu. Collisions between the kinetic and thermal components are performed by sampling a particle from the thermal component and selecting a particle from the kinetic component. Particles are also transferred between the two components according to thermalization and dethermalization probabilities, which are functions of phase space.« less

Probing Nanoparticle Reactivity at the Single-Molecule Level

DTIC Science & Technology

2014-02-15

nanorod hetero - nuclear particle (top) and a bime- tallic nanorod with two metal components (bottom). Both sys- tems have a metal-metal junction . Au...catalysts for co oxidation . J Am Chem Soc 133, 1978–1986 (2011). 32 F. Liu, J. Y. Lee & W. Zhou. Template preparation of multisegment ptni nanorods as...reactivity at nanoscale metal?metal junctions . (a) Papers published in peer-reviewed journals (N/A for none) Enter List of papers submitted or

Single file diffusion into a semi-infinite tube.

PubMed

Farrell, Spencer G; Brown, Aidan I; Rutenberg, Andrew D

2015-11-23

We investigate single file diffusion (SFD) of large particles entering a semi-infinite tube, such as luminal diffusion of proteins into microtubules or flagella. While single-file effects have no impact on the evolution of particle density, we report significant single-file effects for individually tracked tracer particle motion. Both exact and approximate ordering statistics of particles entering semi-infinite tubes agree well with our stochastic simulations. Considering initially empty semi-infinite tubes, with particles entering at one end starting from an initial time t = 0, tracked particles are initially super-diffusive after entering the system, but asymptotically diffusive at later times. For finite time intervals, the ratio of the net displacement of individual single-file particles to the average displacement of untracked particles is reduced at early times and enhanced at later times. When each particle is numbered, from the first to enter (n = 1) to the most recent (n = N), we find good scaling collapse of this distance ratio for all n. Experimental techniques that track individual particles, or local groups of particles, such as photo-activation or photobleaching of fluorescently tagged proteins, should be able to observe these single-file effects. However, biological phenomena that depend on local concentration, such as flagellar extension or luminal enzymatic activity, should not exhibit single-file effects.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yiran; Liu, Siming; Yuan, Qiang, E-mail: liusm@pmo.ac.cn

Recent precise measurements of cosmic-ray (CR) spectra show that the energy distribution of protons is softer than those of heavier nuclei, and there are spectral hardenings for all nuclear compositions above ∼200 GV. Models proposed for these anomalies generally assume steady-state solutions of the particle acceleration process. We show that if the diffusion coefficient has a weak dependence on the particle rigidity near shock fronts of supernova remnants (SNRs), time-dependent solutions of the linear diffusive shock acceleration at two stages of SNR evolution can naturally account for these anomalies. The high-energy component of CRs is dominated by acceleration in themore » free expansion and adiabatic phases with enriched heavy elements and a high shock speed. The low-energy component may be attributed to acceleration by slow shocks propagating in dense molecular clouds with low metallicity in the radiative phase. Instead of a single power-law distribution, the spectra of time-dependent solutions soften gradually with the increase of energy, which may be responsible for the “knee” of CRs.« less

Distributed multi-sensor particle filter for bearings-only tracking

NASA Astrophysics Data System (ADS)

Zhang, Jungen; Ji, Hongbing

2012-02-01

In this article, the classical bearings-only tracking (BOT) problem for a single target is addressed, which belongs to the general class of non-linear filtering problems. Due to the fact that the radial distance observability of the target is poor, the algorithm-based sequential Monte-Carlo (particle filtering, PF) methods generally show instability and filter divergence. A new stable distributed multi-sensor PF method is proposed for BOT. The sensors process their measurements at their sites using a hierarchical PF approach, which transforms the BOT problem from Cartesian coordinate to the logarithmic polar coordinate and separates the observable components from the unobservable components of the target. In the fusion centre, the target state can be estimated by utilising the multi-sensor optimal information fusion rule. Furthermore, the computation of a theoretical Cramer-Rao lower bound is given for the multi-sensor BOT problem. Simulation results illustrate that the proposed tracking method can provide better performances than the traditional PF method.

Evaluation of the BioVigilant IMD-A, a novel optical spectroscopy technology for the continuous and real-time environmental monitoring of viable and nonviable particles. Part II. Case studies in environmental monitoring during aseptic filling, intervention assessments, and glove integrity testing in manufacturing isolators.

PubMed

Miller, Michael J; Walsh, Michael R; Shrake, Jerry L; Dukes, Randall E; Hill, Daniel B

2009-01-01

This paper describes the use of the BioVigilant IMD-A, a real-time and continuous monitoring technology based on optical spectroscopy, to simultaneously and instantaneously detect, size, and enumerate both viable and nonviable particles in a variety of filling and transfer isolator environments during an aseptic fill, transfer of sterilized components, and filling interventions. Continuous monitoring of three separate isolators for more than 16 h and representing more than 28 m3 of air per isolator (under static conditions) yielded a mean viable particle count of zero (0) per cubic meter. Although the mean count per cubic meter was zero, the detection of very low levels of single viable particles was randomly observed in each of these sampling runs. No viable particles were detected during the manual transfer of sterilized components from transfer isolators into a filling isolator, and similar results were observed during an aseptic fill, a filling needle change-out procedure, and during disassembly, movement, and reassembly of a vibrating stopper bowl. During the continuous monitoring of a sample transfer port and a simulated mousehole, no viable particles were detected; however, when the sampling probe was inserted beyond the isolator-room interface, the IMD-A instantaneously detected and enumerated both viable and nonviable particles originating from the surrounding room. Data from glove pinhole studies showed no viable particles being observed, although significant viable particles were immediately detected when the gloves were removed and a bare hand was allowed to introduce microorganisms into the isolator. The IMD-A technology offers the industry an unprecedented advantage over growth-based bioaerosol samplers for monitoring the state of microbiological control in pharmaceutical manufacturing environments, and represents significant progress toward the acceptance of microbiology process analytical technology solutions for the industry.

In-situ single particle composition analysis of free tropospheric ice nuclei and ice residues in mixed-phase clouds during INUIT-JFJ 2013

NASA Astrophysics Data System (ADS)

Schmidt, Susan; Schneider, Johannes; Thomas, Klimach; Stephan, Mertes; Ludwig, Schenk; Udo, Kästner; Frank, Stratmann; Joachim, Curtius; Piotr, Kupiszewski; Ernest, Weingartner; Emanuel, Hammer; Paul, Vochezer; Martin, Schnaiter; Stephan, Borrmann

2014-05-01

In the framework of the DFG (deutsche Forschungsgemeinschaft)-funded research unit INUIT (Ice Nuclei research UnIT) a field campaign at the High Alpine Research Station Jungfraujoch (JFJ, Swiss Alps, Sphinx Laboratory, 3580 m asl; 7°59'2''E, 46°32'53''N) took place in January/February 2013 (INUIT-JFJ 2013). The goal of the measurements was to investigate the chemical composition of ice particle residues (IPR) in ambient air as well as the background aerosol particles. Previous investigations conducted at the JFJ showed that particles consisting of mineral components dominate the ice particle residue number (Kamphus et al., 2008) but also particles consisting of black carbon were found to be enriched in IPR (Mertes et al., 2007; Cozic et al., 2008). Cziczo et al. find out that lead as well is a good ice nucleus and was measured in IPR at previous measurements at the JFJ. During INUIT-JFJ 2013, the IPR were sampled out of mixed-phase clouds by an Ice-CVI (Ice Counterflow Virtual Impactor, Mertes et al., 2007) and an ISI (Ice Selective Inlet, Kupiszewski et al., 2013) and analyzed by the single particle mass spectrometer ALABAMA (Aircraft-based Laser Ablation Aerosol Mass Spectrometer; Brands et al., 2011). Additionally, the ALABAMA was connected to a total aerosol-inlet to investigate the chemical composition of background aerosol particles. During 217 hours of background aerosol measurements we analyzed more than 27000 aerosol particles, which consisted mainly of pure organic components or organics mixed with ammonium, metals or mineral components. During six cloud events with approximately 63 h measurement time we detected 162 IPR sampled by the Ice-CVI. The main part of these IPR were also composed of organic material mixed with other chemical compounds. Additionally, we found particles which consisted of mineral components (approximately 23 %). Sampling mixed-phase cloud through the ISI we measured during four cloud events 34 ice residues in approximately 30 h measurement time. The main part of the chemical compounds of these IPR were also organic material mixed with metals or with mineral compounds. We also found a smaller part of particles which consisted of pure mineral components (about 48 %). Lead was also found in the IPR measured behind Ice-CVI (~14 %) as well as in the background aerosol (~0.04 %). Black carbon particles were only found in the background aerosol. Because of the topography of the JFJ, air masses can reach the station only from the northwestern or southeastern direction (Hammer et al., 2013). Back trajectory calculations show that during our measurements the air masses were dominated mainly by long-distance transport from North America over Great Britain and France. This may explain the lower abundance of mineral dust in the ice residues compared to the previous studies. Brands, M., Kamphus, M., Böttger, T., Schneider, J., Drewnick, F., Roth, A., Curtius, J., Voigt, C., Borbon, A., Beekmann, M., Bourdon, A., Perrin, T. and Borrmann, S. (2011) Aerosol Sci. Technol., 45, 46-64. Cozic, J., Mertes, S., Verheggen, B., Cziczo, D. J., Gallavardin, S. J., Walter, S., Baltensperger, U. and Weingartner, E. (2008) J. Geophys. Res.-Atmos., 113, D15209. Cziczo, D. J., Stetzer. O., Worringen, A., Ebert, M., Weinbruch, S., Kamphus, M., Gallavardin, S. J., Curtius, J., Borrmann, S., Froyd, K. D., Mertes, S., Möhler, O., Lohmann, U. (2009) Nature Geoscience, 2, 333-336 Hammer, E., Bukowiecki, N., Gysel, M., Jurányi, Z., Hoyle, C. R., Vogt, R., Baltensperger, U. and Weingartner, E. (2013) Atmos. Chem. Phys. Discuss., 13, 20419-20462 Kamphus, M., Ettner-Mahl, M., Klimach, T., Drewnick, F, Keller, L., Cziczo, D. J., Mertes, S., Borrmann, S. and Curtius1, J. (2010) Atmos. Chem. Phys., 10, 8077-8095. Kupiszewski, P., Weingartner, E., Färber, R., Gysel, M., Hammer, E., Fuchs, C., Baltensperger, U., Vochezer, P., Schnaiter, M., Linke, C., Toprak, E., Mertes, S., Schneider, J., Schmidt, S. (2013) European Aerosol Conference, Prague. Mertes, S., Verheggen, B., Walter,S., Connolly,P., Ebert, M., Schneider, J., Bower, K. N., Cozic, J., Weinbruch, S., Baltensperger, U. and Weingartner, E. (2007) Aerosol Sci. Technol., 41, 848-864.

Electronic properties of hybrid Cu2S/Ru semiconductor/metallic-cage nanoparticles.

PubMed

Bekenstein, Yehonadav; Vinokurov, Kathy; Banin, Uri; Millo, Oded

2012-12-21

Hybrid inorganic nanoparticles, comprising a semiconducting Cu(2)S quantum-dot (QD) core encapsulated by a metallic Ru cage-like shell, and each of their individual components, are studied via scanning tunneling spectroscopy. Bare Cu(2)S QDs show nearly identical semiconducting-like I-V characteristics while the empty Ru cages exhibit single electron tunneling effects-the Coulomb blockade and staircase. Surprisingly, in some cases negative differential conductance features, with periodicity that correlates to the Coulomb staircase, were observed. The tunneling spectra measured on the hybrid QDs varies greatly along a single particle, manifesting synergetic electrical properties that originate from this unique semiconducting-metallic interface.

Light-field camera-based 3D volumetric particle image velocimetry with dense ray tracing reconstruction technique

NASA Astrophysics Data System (ADS)

Shi, Shengxian; Ding, Junfei; New, T. H.; Soria, Julio

2017-07-01

This paper presents a dense ray tracing reconstruction technique for a single light-field camera-based particle image velocimetry. The new approach pre-determines the location of a particle through inverse dense ray tracing and reconstructs the voxel value using multiplicative algebraic reconstruction technique (MART). Simulation studies were undertaken to identify the effects of iteration number, relaxation factor, particle density, voxel-pixel ratio and the effect of the velocity gradient on the performance of the proposed dense ray tracing-based MART method (DRT-MART). The results demonstrate that the DRT-MART method achieves higher reconstruction resolution at significantly better computational efficiency than the MART method (4-50 times faster). Both DRT-MART and MART approaches were applied to measure the velocity field of a low speed jet flow which revealed that for the same computational cost, the DRT-MART method accurately resolves the jet velocity field with improved precision, especially for the velocity component along the depth direction.

GPU acceleration of particle-in-cell methods

NASA Astrophysics Data System (ADS)

Cowan, Benjamin; Cary, John; Meiser, Dominic

2015-11-01

Graphics processing units (GPUs) have become key components in many supercomputing systems, as they can provide more computations relative to their cost and power consumption than conventional processors. However, to take full advantage of this capability, they require a strict programming model which involves single-instruction multiple-data execution as well as significant constraints on memory accesses. To bring the full power of GPUs to bear on plasma physics problems, we must adapt the computational methods to this new programming model. We have developed a GPU implementation of the particle-in-cell (PIC) method, one of the mainstays of plasma physics simulation. This framework is highly general and enables advanced PIC features such as high order particles and absorbing boundary conditions. The main elements of the PIC loop, including field interpolation and particle deposition, are designed to optimize memory access. We describe the performance of these algorithms and discuss some of the methods used. Work supported by DARPA contract W31P4Q-15-C-0061 (SBIR).

Numerical simulation of submicron particles formation by condensation at coals burning

NASA Astrophysics Data System (ADS)

Kortsenshteyn, N. M.; Petrov, L. V.

2017-11-01

The thermodynamic analysis of the composition of the combustion products of 15 types of coals was carried out with consideration for the formation of potassium and sodium aluminosilicates and solid and liquid slag removal. Based on the results of the analysis, the approximating temperature dependences of the concentrations of condensed components (potassium and sodium sulfates) were obtained for the cases of two-phase and single-phase equilibriums; conclusions on the comparative influence of solid and liquid slag removal on the probability of the formation of submicron particles on the combustion of coals were made. The found dependences was make it possible to perform a numerical simulation of the bulk condensation of potassium and sodium sulfate vapors upon the cooling of coal combustion products in a process flow. The number concentration and size distribution of the formed particles have been determined. Agreement with experimental data on the fraction composition of particles has been reached at a reasonable value of a free parameter of the model.

Coupling discrete and continuum concentration particle models for multiscale and hybrid molecular-continuum simulations

NASA Astrophysics Data System (ADS)

Petsev, Nikolai D.; Leal, L. Gary; Shell, M. Scott

2017-12-01

Hybrid molecular-continuum simulation techniques afford a number of advantages for problems in the rapidly burgeoning area of nanoscale engineering and technology, though they are typically quite complex to implement and limited to single-component fluid systems. We describe an approach for modeling multicomponent hydrodynamic problems spanning multiple length scales when using particle-based descriptions for both the finely resolved (e.g., molecular dynamics) and coarse-grained (e.g., continuum) subregions within an overall simulation domain. This technique is based on the multiscale methodology previously developed for mesoscale binary fluids [N. D. Petsev, L. G. Leal, and M. S. Shell, J. Chem. Phys. 144, 084115 (2016)], simulated using a particle-based continuum method known as smoothed dissipative particle dynamics. An important application of this approach is the ability to perform coupled molecular dynamics (MD) and continuum modeling of molecularly miscible binary mixtures. In order to validate this technique, we investigate multicomponent hybrid MD-continuum simulations at equilibrium, as well as non-equilibrium cases featuring concentration gradients.

Comment on 'Amplification of endpoint structure for new particle mass measurement at the LHC'

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barr, A. J.; Gwenlan, C.; Young, C. J. S.

2011-06-01

We present a comment on the kinematic variable m{sub CT2} recently proposed in Won Sang Cho, Jihn E. Kim, and Ji-Hun Kim, Phys. Rev. D 81, 095010 (2010). The variable is designed to be applied to models such as R-parity conserving supersymmetry (SUSY) when there is pair production of new heavy particles each of which decays to a single massless visible and a massive invisible component. It was proposed by Cho, Kim, and Kim that a measurement of the peak of the m{sub CT2} distribution could be used to precisely constrain the masses of the SUSY particles. We show that,more » for the an example characterized by direct squark decays, when standard model backgrounds are included in simulations, the sensitivity of the m{sub CT2} variable to the SUSY particle masses is more seriously impacted for m{sub CT2} than for other previously proposed variables.« less

Nanotechnology-based approaches for the development of diagnostics, therapeutics, and vaccines.

PubMed

Srinivasan, Alagarsamy; Rastogi, Anshu; Ayyavoo, Velpandi; Srivastava, Shiv

2014-06-01

The architecture of nanoparticles of biological origin, generally also known as bionanoparticles, presents several features that are ideal for their use in developing diagnostics, therapeutics, and vaccines. In this regard, particles formed by viral proteins using recombinant DNA technology resemble authentic virus particles. However, they lack infectivity due to the absence of genetic components such as DNA or RNA. Hence, they are designated as virus-like particles (VLP). VLPs possess the following characteristics: (1) they can be generated by either a single or a few viral proteins; (2) their size, formed by viral proteins, is in the range of 20 to100 nm; (3) the number of protein molecules required for particle assembly is from hundreds to thousands, depending on the VLP; (4) the protein(s) responsible for their assembly are amenable for manipulation; and (5) multiple proteins/peptides can be incorporated into a VLP. The potential advantages of VLPs directed by retroviral proteins are discussed in this review.

Fuzzy inference enhanced information recovery from digital PIV using cross-correlation combined with particle tracking

NASA Technical Reports Server (NTRS)

Wernet, Mark P.

1995-01-01

Particle Image Velocimetry provides a means of measuring the instantaneous 2-component velocity field across a planar region of a seeded flowfield. In this work only two camera, single exposure images are considered where both cameras have the same view of the illumination plane. Two competing techniques which yield unambiguous velocity vector direction information have been widely used for reducing the single exposure, multiple image data: cross-correlation and particle tracking. Correlation techniques yield averaged velocity estimates over subregions of the flow, whereas particle tracking techniques give individual particle velocity estimates. The correlation technique requires identification of the correlation peak on the correlation plane corresponding to the average displacement of particles across the subregion. Noise on the images and particle dropout contribute to spurious peaks on the correlation plane, leading to misidentification of the true correlation peak. The subsequent velocity vector maps contain spurious vectors where the displacement peaks have been improperly identified. Typically these spurious vectors are replaced by a weighted average of the neighboring vectors, thereby decreasing the independence of the measurements. In this work fuzzy logic techniques are used to determine the true correlation displacement peak even when it is not the maximum peak on the correlation plane, hence maximizing the information recovery from the correlation operation, maintaining the number of independent measurements and minimizing the number of spurious velocity vectors. Correlation peaks are correctly identified in both high and low seed density cases. The correlation velocity vector map can then be used as a guide for the particle tracking operation. Again fuzzy logic techniques are used, this time to identify the correct particle image pairings between exposures to determine particle displacements, and thus velocity. The advantage of this technique is the improved spatial resolution which is available from the particle tracking operation. Particle tracking alone may not be possible in the high seed density images typically required for achieving good results from the correlation technique. This two staged approach offers a velocimetric technique capable of measuring particle velocities with high spatial resolution over a broad range of seeding densities.

Measurements of Light Absorbing Particles on Tropical South American Glaciers

NASA Astrophysics Data System (ADS)

Schmitt, C. G.; All, J.; Schwarz, J. P.; Arnott, W. P.; Warthon, J.; Andrade, M.; Celestian, A. J.; Hoffmann, D.; Cole, R. J.; Lapham, E.; Horodyskyj, U. N.; Froyd, K. D.; Liao, J.

2014-12-01

Glaciers in the tropical Andes have been losing mass rapidly in recent decades. In addition to the documented increase in temperature, increases in light absorbing particulates deposited on glaciers could be contributing to the observed glacier loss. Here we present results of measurements of light absorbing particles from glaciers in Peru and Bolivia. Samples have been collected by American Climber Science Program volunteers and scientists at altitudes up to 6770 meters. Collected snow samples were melted and filtered in the field. A new inexpensive technique, the Light Absorption Heating Method (LAHM) has been developed for analysis of light absorbing particles collected on filters. Results from LAHM analysis are calibrated using filters with known amounts of fullerene soot, a common industrial surrogate for black carbon (BC). For snow samples collected at the same field location LAHM analysis and measurements from the Single Particle Soot Photometer (SP2) instrument are well correlated (r2 = 0.92). Co-located SP2 and LAHM filter analysis suggest that BC could be the dominant absorbing component of the light absorbing particles in some areas.

Three Component Velocity and Acceleration Measurement Using FLEET

NASA Technical Reports Server (NTRS)

Danehy, Paul M.; Bathel, Brett F.; Calvert, Nathan; Dogariu, Arthur; Miles, Richard P.

2014-01-01

The femtosecond laser electronic excitation and tagging (FLEET) method has been used to measure three components of velocity and acceleration for the first time. A jet of pure N2 issuing into atmospheric pressure air was probed by the FLEET system. The femtosecond laser was focused down to a point to create a small measurement volume in the flow. The long-lived lifetime of this fluorescence was used to measure the location of the tagged particles at different times. Simultaneous images of the flow were taken from two orthogonal views using a mirror assembly and a single intensified CCD camera, allowing two components of velocity to be measured in each view. These different velocity components were combined to determine three orthogonal velocity components. The differences between subsequent velocity components could be used to measure the acceleration. Velocity accuracy and precision were roughly estimated to be +/-4 m/s and +/-10 m/s respectively. These errors were small compared to the approx. 100 m/s velocity of the subsonic jet studied.

Molecular ways to nanoscale particles and films

NASA Astrophysics Data System (ADS)

Shen, H.; Mathur, S.

2002-06-01

Chemical routes for the synthesis of nanoparticles and films are proving to be highly efficient and versatile in tailoring the elemental combination and intrinsic properties of the target materials. The use of molecular compounds allows a controlled interaction of atoms or molecules, when compared to the solid-state methods, resulting in the formation of compositionally homogeneous deposits or uniform solid particles. Assembling all the elements forming the material in a single molecular compound, the so-called single-source approach augments the formation of nanocrystalline phases at low temperatures with atomically precise structures. To this end, we have shown that predefined reaction (decomposition) chemistry of precursors enforces a molecular level homogeneity in the obtained materials. Following the single-step conversions of appropriate molecular sources, we have obtained films and nanoparticles of oxides (Fe3O4, BaTiO3, ZnAl2O4, CoAl2O4), metal/oxide composites (Ge/GeO2) and ceramic-ceramic composites (LnAIO3/AI2O3; Ln = Pr, Nd). For a comparative evaluation, CoAl2O4 nanoparticles were prepared by both single- and multi-component routes; whereas the single-source approach yielded monophasic high purity spinels, phase contamination, due to monometal phases, was observed in the ceramic obtained from multicomponent mixture. An account of the size-controlled synthesis and characterisation of the new ceramics and composites is presented.

Modelling of strong heterogeneities in aerosol single scattering albedos over a polluted region

NASA Astrophysics Data System (ADS)

Mallet, M.; Pont, V.; Liousse, C.

2005-05-01

To date, most models dedicated to the investigation of aerosol direct or semi-direct radiative forcings have assumed the various aerosol components to be either completely externally mixed or homogeneously internally mixed. Some recent works have shown that a core-shell treatment of particles should be more realistic, leading to significant differences in the radiative impact as compared to only externally or well-internally mixed states. To account for these studies, an optical module, ORISAM-RAD, has been developed for computing aerosol radiative properties under the hypothesis of internally mixed particles with a n-layer spherical concentric structure. Mesoscale simulations using ORISAM-RAD, coupled with the 3D mesoscale model Meso-NH-C, have been performed for one selected day (06/24/2001) during the ESCOMPTE experiment in the Marseilles-Fos/Berre region, which illustrate the ability of this new module to reproduce spatial heterogeneities of measured single scattering albedo (ωo), due to industrial and/or urban pollution plumes.

Molecular dynamics of single-particle impacts predicts phase diagrams for large scale pattern formation.

PubMed

Norris, Scott A; Samela, Juha; Bukonte, Laura; Backman, Marie; Djurabekova, Flyura; Nordlund, Kai; Madi, Charbel S; Brenner, Michael P; Aziz, Michael J

2011-01-01

Energetic particle irradiation can cause surface ultra-smoothening, self-organized nanoscale pattern formation or degradation of the structural integrity of nuclear reactor components. A fundamental understanding of the mechanisms governing the selection among these outcomes has been elusive. Here we predict the mechanism governing the transition from pattern formation to flatness using only parameter-free molecular dynamics simulations of single-ion impacts as input into a multiscale analysis, obtaining good agreement with experiment. Our results overturn the paradigm attributing these phenomena to the removal of target atoms via sputter erosion: the mechanism dominating both stability and instability is the impact-induced redistribution of target atoms that are not sputtered away, with erosive effects being essentially irrelevant. We discuss the potential implications for the formation of a mysterious nanoscale topography, leading to surface degradation, of tungsten plasma-facing fusion reactor walls. Consideration of impact-induced redistribution processes may lead to a new design criterion for stability under irradiation.

Detecting single-electron events in TEM using low-cost electronics and a silicon strip sensor.

PubMed

Gontard, Lionel C; Moldovan, Grigore; Carmona-Galán, Ricardo; Lin, Chao; Kirkland, Angus I

2014-04-01

There is great interest in developing novel position-sensitive direct detectors for transmission electron microscopy (TEM) that do not rely in the conversion of electrons into photons. Direct imaging improves contrast and efficiency and allows the operation of the microscope at lower energies and at lower doses without loss in resolution, which is especially important for studying soft materials and biological samples. We investigate the feasibility of employing a silicon strip detector as an imaging detector for TEM. This device, routinely used in high-energy particle physics, can detect small variations in electric current associated with the impact of a single charged particle. The main advantages of using this type of sensor for direct imaging in TEM are its intrinsic radiation hardness and large detection area. Here, we detail design, simulation, fabrication and tests in a TEM of the front-end electronics developed using low-cost discrete components and discuss the limitations and applications of this technology for TEM.

Overview on Sobemoviruses and a Proposal for the Creation of the Family Sobemoviridae

PubMed Central

Sõmera, Merike; Sarmiento, Cecilia; Truve, Erkki

2015-01-01

The genus Sobemovirus, unassigned to any family, consists of viruses with single-stranded plus-oriented single-component RNA genomes and small icosahedral particles. Currently, 14 species within the genus have been recognized by the International Committee on Taxonomy of Viruses (ICTV) but several new species are to be recognized in the near future. Sobemovirus genomes are compact with a conserved structure of open reading frames and with short untranslated regions. Several sobemoviruses are important pathogens. Moreover, over the last decade sobemoviruses have become important model systems to study plant virus evolution. In the current review we give an overview of the structure and expression of sobemovirus genomes, processing and functions of individual proteins, particle structure, pathology and phylogenesis of sobemoviruses as well as of satellite RNAs present together with these viruses. Based on a phylogenetic analysis we propose that a new family Sobemoviridae should be recognized including the genera Sobemovirus and Polemovirus. Finally, we outline the future perspectives and needs for the research focusing on sobemoviruses. PMID:26083319

Theoretical and experimental analysis of a linear accelerator endowed with single feed coupler with movable short-circuit.

PubMed

Dal Forno, Massimo; Craievich, Paolo; Penco, Giuseppe; Vescovo, Roberto

2013-11-01

The front-end injection systems of the FERMI@Elettra linac produce high brightness electron beams that define the performance of the Free Electron Laser. The photoinjector mainly consists of the radiofrequency (rf) gun and of two S-band rf structures which accelerate the beam. Accelerating structures endowed with a single feed coupler cause deflection and degradation of the electron beam properties, due to the asymmetry of the electromagnetic field. In this paper, a new type of single feed structure with movable short-circuit is proposed. It has the advantage of having only one waveguide input, but we propose a novel design where the dipolar component is reduced. Moreover, the racetrack geometry allows to reduce the quadrupolar component. This paper presents the microwave design and the analysis of the particle motion inside the linac. A prototype has been machined at the Elettra facility to verify the new coupler design and the rf field has been measured by adopting the bead-pull method. The results are here presented, showing good agreement with the expectations.

Continuum mesoscopic framework for multiple interacting species and processes on multiple site types and/or crystallographic planes.

PubMed

Chatterjee, Abhijit; Vlachos, Dionisios G

2007-07-21

While recently derived continuum mesoscopic equations successfully bridge the gap between microscopic and macroscopic physics, so far they have been derived only for simple lattice models. In this paper, general deterministic continuum mesoscopic equations are derived rigorously via nonequilibrium statistical mechanics to account for multiple interacting surface species and multiple processes on multiple site types and/or different crystallographic planes. Adsorption, desorption, reaction, and surface diffusion are modeled. It is demonstrated that contrary to conventional phenomenological continuum models, microscopic physics, such as the interaction potential, determines the final form of the mesoscopic equation. Models of single component diffusion and binary diffusion of interacting particles on single-type site lattice and of single component diffusion on complex microporous materials' lattices consisting of two types of sites are derived, as illustrations of the mesoscopic framework. Simplification of the diffusion mesoscopic model illustrates the relation to phenomenological models, such as the Fickian and Maxwell-Stefan transport models. It is demonstrated that the mesoscopic equations are in good agreement with lattice kinetic Monte Carlo simulations for several prototype examples studied.

Evaluation of commercial ADC radiation tolerance for accelerator experiments

DOE PAGES

Chen, K.; Chen, H.; Kierstead, J.; ...

2015-08-17

Electronic components used in high energy physics experiments are subjected to a radiation background composed of high energy hadrons, mesons and photons. These particles can induce permanent and transient effects that affect the normal device operation. Ionizing dose and displacement damage can cause chronic damage which disable the device permanently. Transient effects or single event effects are in general recoverable with time intervals that depend on the nature of the failure. The magnitude of these effects is technology dependent with feature size being one of the key parameters. Analog to digital converters are components that are frequently used in detectormore » front end electronics, generally placed as close as possible to the sensing elements to maximize signal fidelity. We report on radiation effects tests conducted on 17 commercially available analog to digital converters and extensive single event effect measurements on specific twelve and fourteen bit ADCs that presented high tolerance to ionizing dose. We discuss mitigation strategies for single event effects (SEE) for their use in the large hadron collider environment.« less

Nanoparticle generation and interactions with surfaces in vacuum systems

NASA Astrophysics Data System (ADS)

Khopkar, Yashdeep

Extreme ultraviolet lithography (EUVL) is the most likely candidate as the next generation technology beyond immersion lithography to be used in high volume manufacturing in the semiconductor industry. One of the most problematic areas in the development process is the fabrication of mask blanks used in EUVL. As the masks are reflective, there is a chance that any surface aberrations in the form of bumps or pits could be printed on the silicon wafers. There is a strict tolerance to the number density of such defects on the mask that can be used in the final printing process. Bumps on the surface could be formed when particles land on the mask blank surface during the deposition of multiple bi-layers of molybdenum and silicon. To identify, and possibly mitigate the source of particles during mask fabrication, SEMATECH investigated particle generation in the VEECO Nexus deposition tool. They found several sources of particles inside the tool such as valves. To quantify the particle generation from vacuum components, a test bench suitable for evaluating particle generation in the sub-100 nm particle size range was needed. The Nanoparticle test bench at SUNY Polytechnic Institute was developed as a sub-set of the overall SEMATECH suite of metrology tools used to identify and quantify sources of particles inside process tools that utilize these components in the semiconductor industry. Vacuum valves were tested using the test bench to investigate the number, size and possible sources of particles inside the valves. Ideal parameters of valve operation were also investigated using a 300-mm slit valve with the end goal of finding optimized parameters for minimum particle generation. SEMATECH also pursued the development of theoretical models of particle transport replicating the expected conditions in an ion beam deposition chamber assuming that the particles were generated. In the case of the ion beam deposition tool used in the mask blank fabrication process, the ion beam in the tool could significantly accelerate particles. Assuming that these particles are transported to various surfaces inside the deposition tool, the next challenge is to enhance the adhesion of the particles on surfaces that are located in the non-critical areas inside the tool. However, for particles in the sub-100 nm size range, suitable methods do not exist that can compare the adhesion probability of particles upon impact for a wide range of impact velocities, surfaces and particle types. Traditional methods, which rely on optical measurement of particle velocities in the micron-size regime, cannot be used for sub-100 nm particles as the particles do not scatter sufficient light for the detectors to function. All the current methods rely on electrical measurements taken from impacting particles onto a surface. However, for sub-100 nm particles, the impact velocity varies in different regions of the same impaction spot. Therefore, electrical measurements are inadequate to quantify the exact adhesion characteristics at different impact velocities to enable a comparison of multiple particle-surface systems. Therefore, we propose a new method based on the use of scanning electron microscopy (SEM) imaging to study the adhesion of particles upon impact on surfaces. The use of SEM imaging allows for single particle detection across a single impaction spot and, therefore, enables the comparison of different regions with different impact velocities in a single impaction spot. The proposed method will provide comprehensive correlation between the adhesion probability of sub-100 nm particles and a wide range of impact velocities and angles. The location of each particle is compared with impact velocity predicted by using computational fluid dynamics methods to generate a comprehensive adhesion map involving the impact of 70 nm particles on a polished surface across a large impact velocity range. The final adhesion probability map shows higher adhesion at oblique impact angles compared to normal incidence impacts. Theoretical and experiments with micron-sized particles have shown that the contact area between the particle and the surface decreases at lower incidence angles which results in a decrease in the adhesion probability of the particle. The most likely cause of this result was the role of plastic deformation of particles and its effect on adhesion. Therefore, 70 nm sucrose particles were also impacted under similar impaction conditions to compare the role of plastic deformation on the adhesion characteristics of a particle. Sucrose particles have approximately 10 times more modulus of elasticity than Polystyrene Latex (PSL) particles and were found to have almost no adhesion on the surface at the same impact velocities where the highest adhesion of PSL particles was measured. Besides the role of plastic deformation, the influence of other possible errors in this process was investigated but not found to be significant. (Abstract shortened by UMI.).

Particle Streak Anemometry: A New Method for Proximal Flow Sensing from Aircraft

NASA Astrophysics Data System (ADS)

Nichols, T. W.

Accurate sensing of relative air flow direction from fixed-wing small unmanned aircraft (sUAS) is challenging with existing multi-hole pitot-static and vane systems. Sub-degree direction accuracy is generally not available on such systems and disturbances to the local flow field, induced by the airframe, introduce an additional error source. An optical imaging approach to make a relative air velocity measurement with high-directional accuracy is presented. Optical methods offer the capability to make a proximal measurement in undisturbed air outside of the local flow field without the need to place sensors on vulnerable probes extended ahead of the aircraft. Current imaging flow analysis techniques for laboratory use rely on relatively thin imaged volumes and sophisticated hardware and intensity thresholding in low-background conditions. A new method is derived and assessed using a particle streak imaging technique that can be implemented with low-cost commercial cameras and illumination systems, and can function in imaged volumes of arbitrary depth with complex background signal. The new technique, referred to as particle streak anemometry (PSA) (to differentiate from particle streak velocimetry which makes a field measurement rather than a single bulk flow measurement) utilizes a modified Canny Edge detection algorithm with a connected component analysis and principle component analysis to detect streak ends in complex imaging conditions. A linear solution for the air velocity direction is then implemented with a random sample consensus (RANSAC) solution approach. A single DOF non-linear, non-convex optimization problem is then solved for the air speed through an iterative approach. The technique was tested through simulation and wind tunnel tests yielding angular accuracies under 0.2 degrees, superior to the performance of existing commercial systems. Air speed error standard deviations varied from 1.6 to 2.2 m/s depending on the techniques of implementation. While air speed sensing is secondary to accurate flow direction measurement, the air speed results were in line with commercial pitot static systems at low speeds.

Nanotomography and Micromagnetic Modelling of Remanence Carriers in the Semarkona LL3.0 Chondrite: A New View of the Vortex State

NASA Astrophysics Data System (ADS)

Harrison, R. J.; Einsle, J. F.; Williams, W.; Ó Conbhuí, P.; Fu, R. R.; Weiss, B. P.; Kasama, T.

2015-12-01

Dusty-olivine chondrules are carriers of stable pre-accretionary remanence, and have recently been used to obtain the first reliable estimate of the magnetic field of the early solar nebula. Here we show how the magnetic architecture of a single dusty olivine grain from the Semarkona LL3.0 ordinary chondrite meteorite can be fully characterised in three-dimensions, using a combination of Focussed-Ion-Beam nanotomography (FIB-nt), electron tomography and finite-element micromagnetic modelling. We present a 3D volume reconstruction of a dusty olivine grain, obtained by selective milling through a region of interest in a series of sequential 20 nm slices, which are then imaged using scanning electron microscopy. The data provide a quantitative description of the iron particle ensemble, including the distribution of particle sizes, shapes, interparticle spacings and preferred orientations. Iron particles are predominantly oblate ellipoids. Particles nucleate on dislocation networks and are loosely arranged in a series of parallel sheets with their shortest dimension oriented normal to the sheets and their longest dimensions preferentially aligned within the sheets. Individual particle geometries are converted to a finite-element mesh and used to perform micromagnetic simulations. The majority of particles adopt a single vortex state, with 'bulk' spins that rotate around a central vortex core. The results challenge pre-conceived ideas about the remanence carrying properties of vortex states. We find that remanence is carried by bulk spins rather than the vortex core. Although the orientation of the core is determined by the ellipsoidal geometry (parallel to the major axis for prolate ellipsoids; parallel to the minor axis for oblate ellipsoids), the remanence vectors generally lie at large angles (and in many cases antiparallel) to the core magnetisation. Even in the case of prolate particles, the resulting remanence vector can make a large angle of ~50° to the expected easy axis. The results reconcile the predicted and observed directions of remanence anisotropy, and demonstrate how this combination of nanotomography and micromagnetics will become an essential component of future single-crystal paleomagnetic studies.

Comparison of three-dimensional particle tracking and sizing using plenoptic imaging and digital in-line holography.

PubMed

Hall, Elise M; Thurow, Brian S; Guildenbecher, Daniel R

2016-08-10

Digital in-line holography (DIH) and plenoptic photography are two techniques for single-shot, volumetric measurement of 3D particle fields. Here we present a comparison of the two methods by applying plenoptic imaging to experimental configurations that have been previously investigated with DIH. These experiments include the tracking of secondary droplets from the impact of a water drop on a thin film of water and tracking of pellets from a shotgun. Both plenoptic imaging and DIH successfully quantify the 3D nature of these particle fields. This includes measurement of the 3D particle position, individual particle sizes, and three-component velocity vectors. For the initial processing methods presented here, both techniques give out-of-plane positional accuracy of approximately 1-2 particle diameters. For a fixed image sensor, digital holography achieves higher effective in-plane spatial resolutions. However, collimated and coherent illumination makes holography susceptible to image distortion through index of refraction gradients, as demonstrated in the shotgun experiments. In contrast, plenoptic imaging allows for a simpler experimental configuration and, due to the use of diffuse, white-light illumination, plenoptic imaging is less susceptible to image distortion in the shotgun experiments.

The structure of Escherichia coli signal recognition particle revealed by scanning transmission electron microscopy.

PubMed

Mainprize, Iain L; Beniac, Daniel R; Falkovskaia, Elena; Cleverley, Robert M; Gierasch, Lila M; Ottensmeyer, F Peter; Andrews, David W

2006-12-01

Structural studies on various domains of the ribonucleoprotein signal recognition particle (SRP) have not converged on a single complete structure of bacterial SRP consistent with the biochemistry of the particle. We obtained a three-dimensional structure for Escherichia coli SRP by cryoscanning transmission electron microscopy and mapped the internal RNA by electron spectroscopic imaging. Crystallographic data were fit into the SRP reconstruction, and although the resulting model differed from previous models, they could be rationalized by movement through an interdomain linker of Ffh, the protein component of SRP. Fluorescence resonance energy transfer experiments determined interdomain distances that were consistent with our model of SRP. Docking our model onto the bacterial ribosome suggests a mechanism for signal recognition involving interdomain movement of Ffh into and out of the nascent chain exit site and suggests how SRP could interact and/or compete with the ribosome-bound chaperone, trigger factor, for a nascent chain during translation.

Review of progress in magnetic particle inspection

NASA Astrophysics Data System (ADS)

Eisenmann, David J.; Enyart, Darrel; Lo, Chester; Brasche, Lisa

2014-02-01

Magnetic particle inspection (MPI) has been widely utilized for decades, and sees considerable use in the aerospace industry with a majority of the steel parts being inspected with MPI at some point in the lifecycle. Typical aircraft locations inspected are landing gear, engine components, attachment hardware, and doors. In spite of its numerous applications the method remains poorly understood, and there are many aspects of that method which would benefit from in-depth study. This shortcoming is due to the fact that MPI combines the complicated nature of electromagnetics, metallurgical material effects, fluid-particle motion dynamics, and physiological human factors into a single inspection. To promote understanding of the intricate method issues that affect sensitivity, or to assist with the revision of industry specifications and standards, research studies will be prioritized through the guidance of a panel of industry experts, using an approach which has worked successfully in the past to guide fluorescent penetrant inspection (FPI) research efforts.

Coupling of the microphysical and optical properties of an Arctic nimbostratus cloud during the ASTAR 2004 experiment: Implications for light-scattering modeling

NASA Astrophysics Data System (ADS)

Jourdan, Olivier; Mioche, Guillaume; Garrett, Timothy J.; SchwarzenböCk, Alfons; Vidot, JéRôMe; Xie, Yu; Shcherbakov, Valery; Yang, Ping; Gayet, Jean-FrançOis

2010-12-01

Airborne measurements in an Arctic mixed-phase nimbostratus cloud were conducted in Spitsbergen on 21 May 2004 during the international Arctic Study of Tropospheric Aerosol, Clouds and Radiation (ASTAR) campaign. The in situ instrument suite aboard the Alfred Wegener Institute Polar 2 aircraft included a polar nephelometer (PN), a cloud particle imager (CPI), a Nevzorov probe, and a standard PMS 2DC probe to measure the cloud particle single-scattering properties (at a wavelength of 0.8 μm), and the particle morphology and size, as well as the in-cloud partitioning of ice/water content. The main objective of this work is to present a technique based on principal component analysis and light-scattering modeling to link the microphysical properties of cloud particles to their optical characteristics. The technique is applied to the data collected during the 21 May case study where a wide variety of ice crystal shapes and liquid water fractions were observed at temperatures ranging from -1°C to -12°C. CPI measurements highlight the presence of large supercooled water droplets with diameters close to 500 μm. Although the majority of ice particles were found to have irregular shapes, columns and needles were the prevailing regular habits between -3°C and -6°C while stellars and plates were observed at temperatures below -8°C. The implementation of the principal component analysis of the PN scattering phase function measurements revealed representative optical patterns that were consistent with the particle habit classification derived from the CPI. This indicates that the synergy between the CPI and the PN can be exploited to link the microphysical and shape properties of cloud particles to their single-scattering characteristics. Using light-scattering modeling, we have established equivalent microphysical models based on a limited set of free parameters (roughness, mixture of idealized particle habits, and aspect ratio of ice crystals) that reproduce the main optical features assessed for cloud regions with different particle geometries and liquid water fractions. However, the retrieved bulk microphysical parameters can substantially differ from the measurements (by several times for the effective size and up to 3 orders of magnitude for the number concentration). Several possible explanations for these discrepancies are discussed. The retrievals show that the optical contribution of small particles with sizes lower than 50 μm (droplets and ice crystals) is significant, always exceeding 50% of the total scattering signal, and thus needs to be more accurately quantified. The shattering of large ice crystals on the shrouded inlet of the PN could also strongly affect the retrieved microphysical parameters.

Single particle electrochemical sensors and methods of utilization

DOEpatents

Schoeniger, Joseph [Oakland, CA; Flounders, Albert W [Berkeley, CA; Hughes, Robert C [Albuquerque, NM; Ricco, Antonio J [Los Gatos, CA; Wally, Karl [Lafayette, CA; Kravitz, Stanley H [Placitas, NM; Janek, Richard P [Oakland, CA

2006-04-04

The present invention discloses an electrochemical device for detecting single particles, and methods for using such a device to achieve high sensitivity for detecting particles such as bacteria, viruses, aggregates, immuno-complexes, molecules, or ionic species. The device provides for affinity-based electrochemical detection of particles with single-particle sensitivity. The disclosed device and methods are based on microelectrodes with surface-attached, affinity ligands (e.g., antibodies, combinatorial peptides, glycolipids) that bind selectively to some target particle species. The electrodes electrolyze chemical species present in the particle-containing solution, and particle interaction with a sensor element modulates its electrolytic activity. The devices may be used individually, employed as sensors, used in arrays for a single specific type of particle or for a range of particle types, or configured into arrays of sensors having both these attributes.

Intracellular Trafficking of Silicon Particles and Logic-Embedded Vectors

PubMed Central

Ferrati, Silvia; Mack, Aaron; Chiappini, Ciro; Liu, Xuewu; Bean, Andrew J.; Ferrari, Mauro; Serda, Rita E.

2010-01-01

Mesoporous silicon particles show great promise for use in drug delivery and imaging applications as carriers for second-stage nanoparticles and higher order particles or therapeutics. Modulation of particle geometry, surface chemistry, and porosity allows silicon particles to be optimized for specific applications such as vascular targeting and avoidance of biological barriers commonly found between the site of drug injection and the final destination. In this study, the intracellular trafficking of unloaded carrier silicon particles and carrier particles loaded with secondary iron oxide nanoparticles was investigated. Following cellular uptake, membrane-encapsulated silicon particles migrated to the perinuclear region of the cell by a microtubule-driven mechanism. Surface charge, shape (spherical and hemispherical) and size (1.6 and 3.2 μm) of the particle did not alter the rate of migration. Maturation of the phagosome was associated with an increase in acidity and acquisition of markers of late endosomes and lysosomes. Cellular uptake of iron oxide nanoparticle-loaded silicon particles resulted in sorting of the particles and trafficking to unique destinations. The silicon carriers remained localized in phagosomes, while the second stage iron oxide nanoparticles were sorted into multi-vesicular bodies that dissociated from the phagosome into novel membrane-bound compartments. Release of iron from the cells may represent exocytosis of iron oxide nanoparticle-loaded vesicles. These results reinforce the concept of multi-functional nanocarriers, in which different particles are able to perform specific tasks, in order to deliver single- or multi-component payloads to specific sub-cellular compartments. PMID:20820744

Lepidocrocite to Maghemite to Hematite: A way to have Magnetic and Hematitic Martian Soil

NASA Technical Reports Server (NTRS)

Morris, Richard V.; Golden, D. C.; Shelfer, Tad D.; Lauer, H. V., Jr.

1997-01-01

We examined decomposition products of lepidocrocite, which were produced by heating the phase in air at temperatures up to 525 C for 3 and 300 hr, by XRD, TEM, magnetic methods, and reflectance spectroscopy (visible and near-IR). Single-crystal lepidocrocite particles dehydroxilated to polycrystalline particles of disordered maghemite which subsequently transformed to polycrystalline particles of hematite. Essentially pure maghemite was obtained at 265 and 223 C for the 3 and 300 hr heating experiments, respectively. Its saturation magnetization (J(sub s)) and mass specific susceptibility are approximately 50 A(sq m)/kg and approximately 40 cubic micrometers/kg, respectively. Because hematite is spectrally dominant, spectrally-hematitic samples (i.e., characterized bv a minimum near 860 nm and a maximum near 750 nm) could also be strongly magnetic (J(sub s) up to approximately 30 A(sq m)/kg) from the masked maghemite component. TEM analyses showed that individual particles are polycrystalline with respect to both maghemite and hematite. The spectrally-hematitic and magnetic Mh+Hm particles can satisfy the spectral and magnetic constraints for Martian surface materials over a wide range of values of Mh/(Mh+Hm) and as either pure oxide powders or (within limits) as components of multiphase particles. These experiments are consistent with lepidocrocite as the precursor of Mh+Hm assemblages on Mars, but other phases (e.g., magnetite) that decompose to Mh and Hm are also possible precursors. Simulations done with a copy of the Mars Pathfinder Magnet Array showed that spectrally hematitic Mh+Hm powders having J(sub s) equal to 20.6 A(sq m)/kg adhered to all five magnets.

Exchange-biased quantum tunnelling in a supramolecular dimer of single-molecule magnets.

PubMed

Wernsdorfer, Wolfgang; Aliaga-Alcalde, Núria; Hendrickson, David N; Christou, George

2002-03-28

Various present and future specialized applications of magnets require monodisperse, small magnetic particles, and the discovery of molecules that can function as nanoscale magnets was an important development in this regard. These molecules act as single-domain magnetic particles that, below their blocking temperature, exhibit magnetization hysteresis, a classical property of macroscopic magnets. Such 'single-molecule magnets' (SMMs) straddle the interface between classical and quantum mechanical behaviour because they also display quantum tunnelling of magnetization and quantum phase interference. Quantum tunnelling of magnetization can be advantageous for some potential applications of SMMs, for example, in providing the quantum superposition of states required for quantum computing. However, it is a disadvantage in other applications, such as information storage, where it would lead to information loss. Thus it is important to both understand and control the quantum properties of SMMs. Here we report a supramolecular SMM dimer in which antiferromagnetic coupling between the two components results in quantum behaviour different from that of the individual SMMs. Our experimental observations and theoretical analysis suggest a means of tuning the quantum tunnelling of magnetization in SMMs. This system may also prove useful for studying quantum tunnelling of relevance to mesoscopic antiferromagnets.

Long period seismic signals observed before the Caldera formation during the 2000 Miyake- jima volcanic activity

NASA Astrophysics Data System (ADS)

Ohminato, T.; Kobayashi, T.; Ida, Y.; Fujita, E.

2006-12-01

During the 2000 Miyake-jima volcanic activity started on 26 June 2000, an intense earthquake swarm occurred initially beneath the southwest flank near the summit and gradually migrated west of the island. A volcanic earthquake activity in the island was reactivated beneath the summit, leading to a summit eruption with a significant summit subsidence on 8 July. We detected small but numerous number of long period (LP) seismic signals during these activities. Most of them include both 0.2 and 0.4 Hz components suggesting an existence of a harmonic oscillator. Some of them have dominant frequency peak at 0.2Hz (LP1), while others have one at 0.4 Hz (LP2). At the beginning of each waveform of both LP1 and LP2, an impulsive signal with a pulse-width of about 2 s is clearly identified. The major axis of the particle motion for the initial impulsive signal is almost horizontal suggesting a shallow source beneath the summit, while the inclined particle motion for the latter phase suggests deeper source beneath the island. For both LP1 and LP2, we can identify a clear positive correlation between the amplitude of the initial pulse and that of the latter phase. We conducted waveform inversions for the LP events assuming a point source and determined the locations and mechanisms simultaneously. We assumed three types of source mechanisms; three single forces, six moment tensor components, and a combination of moment tensor and single forces. We used AIC to decide the optimal solutions. Firstly, we applied the method to the entire waveform including both the initial pulse and the latter phase. The source type with a combination of moment tensor and single force components yields the minimum values of the AIC for both LP events. However, the spatial distribution of the residual errors tends to have two local minima. Considering the error distribution and the characteristic particle motions, it is likely that the source of the LP event consists of two different parts. We thus divided the LP events into two parts; the initial and the latter phases, and applied the same waveform inversion procedure separately for each part of the waveform. The inversion results show that the initial impulsive phase and the latter oscillatory phase are well explained by a nearly horizontal single force and a moment solution, respectively. The single force solutions of the initial pulse are positioned at the depth of about 2 km beneath the summit. The single force initially oriented to the north, and then to the south. On the other hand, the sources of the moment solutions are significantly deeper than the single force solutions. The hypocenter of the later phase of LP1 is located at the depth of 5.5 km in the southern region of the island, while that for the LP2 event is at 5.1 km beneath the summit. The horizontal oscillations are relatively dominant for both the LP1 and LP2 events. Although the two sources are separated each other by several kilometers, the positive correlation between the amplitudes of the initial pulse and the latter phase strongly suggests that the shallow sources trigger the deeper sources. The source time histories of the 6 moment tensor components of the latter portion of the LP1 and LP2 are not in phase. This makes it difficult to extract information on source geometry using the amplitude ratio among moment tensor components in a traditional manner. It may suggest that the source is composed of two independent sources whose oscillations are out of phase.

Single shot ultrafast dynamic ellipsometry (UDE) of laser-driven shocks in single crystal explosives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whitley, Von H; Mcgrane, Shawn D; Moore, David S

2009-01-01

We report on the first experiments to measure states in shocked energetic single crystals with dynamic ellipsometry. We demonstrate that these ellipsometric techniques can produce reasonable Hugoniot values using small amounts of crystalline RDX and PETN. Pressures, particle velocities and shock velocities obtained using shocked ellipsometry are comparable to those found using gas-gun flyer plates and molecular dynamics calculations. The adaptation of the technique from uniform thin films of polymers to thick non-perfect crystalline materials was a significant achievement. Correct sample preparation proved to be a crucial component. Through trial and error, we were able to resolve polishing issues, samplemore » quality problems, birefringence effects and mounting difficulties that were not encountered using thin polymer films.« less

Pulse flux measuring device

DOEpatents

Riggan, William C.

1985-01-01

A device for measuring particle flux comprises first and second photodiode detectors for receiving flux from a source and first and second outputs for producing first and second signals representing the flux incident to the detectors. The device is capable of reducing the first output signal by a portion of the second output signal, thereby enhancing the accuracy of the device. Devices in accordance with the invention may measure distinct components of flux from a single source or fluxes from several sources.

Single surface barrier detectors for neutron dosimetry and associated light-ion fluxes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Treado, P.A.; Allas, R.G.; Eman, B.

1981-04-01

In this paper the authors have attempted to perfect a simple, compact and inexpensive single surface barrier detection system to measure both the intensities and approximate spectral shape of continuous neutron and light ion fluxes. They have measured such fluxes for three known collimated and uncollimated neutron beams with two geometrical configurations and with at least two different thicknesses of CH/sub 2/ and CD/sub 2/ radiators. All neutron flux data were obtained with a Au shield in front of the detector; this was removed for LIF measurements. The known shapes of the impinging neutron beams were used to calculate themore » expected recoil-particle spectra and such predictions have been compared with the experimental data. Also, data have been obtained with telescopes, with carbon foil and thin detector-grade silicon foil radiators. These data allow the authors to estimate contributions to the higher-energy portion of the recoil-particle spectra from reactions due to the carbon in the CH/sub 2/ and CD/sub 2/ radiators and due to the silicon in the detector. Corrections for rim effects in the detector and multiple scattering in the radiator are calculable. The precipitous decrease in the number of observed events, expected at the maximum energy that can be deposited by a recoil particle from the radiator, was observed for each of the radiator/detector combinations studied. The data agree reasonably well with both the intensity and spectral shape predictions for recoil-particle energies above about 300 keV. The telescope data confirm the single-detector data and add significant information about the LIFs created by the collimation of the neutron beams. In fact, both the single-detector and telescope data indicate that (n,p) reactions in collimation and target-backing materials contribute significant proton components to the light-ion fluxes.« less

Single-particle speciation of alkylamines in ambient aerosol at five European sites.

PubMed

Healy, Robert M; Evans, Greg J; Murphy, Michael; Sierau, Berko; Arndt, Jovanna; McGillicuddy, Eoin; O'Connor, Ian P; Sodeau, John R; Wenger, John C

2015-08-01

Alkylamines are associated with both natural and anthropogenic sources and have been detected in ambient aerosol in a variety of environments. However, little is known about the ubiquity or relative abundance of these species in Europe. In this work, ambient single-particle mass spectra collected at five sampling sites across Europe have been analysed for their alkylamine content. The aerosol time-of-flight mass spectrometer (ATOFMS) data used were collected in Ireland (Cork), France (Paris, Dunkirk and Corsica) and Switzerland (Zurich) between 2008 and 2013. Each dataset was queried for mass spectral marker ions associated with the following ambient alkylamines: dimethylamine (DMA), trimethylamine (TMA), diethylamine (DEA), triethylamine (TEA), dipropylamine (DPA) and tripropylamine (TPA). The fraction of ambient particles that contained detectable alkylamines ranged from 1 to 17 % depending on location, with the highest fractions observed in Paris and Zurich in the winter months. The lowest fractions were observed at coastal sites, where the influence of animal husbandry-related alkylamine emissions is also expected to be lowest. TMA was the most ubiquitous particle phase alkylamine detected and was observed at all locations. Alkylamines were found to be internally mixed with both sulphate and nitrate for each dataset, suggesting that aminium salt formation may be important at all sites investigated. Interestingly, in Corsica, all alkylamine particles detected were also found to be internally mixed with methanesulphonic acid (MSA), indicating that aminium methanesulphonate salts may represent a component of marine ambient aerosol in the summer months. Internal mixing of alkylamines with sea salt was not observed, however. Alkylamine-containing particle composition was found to be reasonably homogeneous at each location, with the exception of the Corsica and Dunkirk sites, where two and four distinct mixing states were observed, respectively.

Development of Modeling and Simulation for Magnetic Particle Inspection Using Finite Elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Jun-Youl

2003-01-01

Magnetic particle inspection (MPI) is a widely used nondestructive inspection method for aerospace applications essentially limited to experiment-based approaches. The analysis of MPI characteristics that affect sensitivity and reliability contributes not only reductions in inspection design cost and time but also improvement of analysis of experimental data. Magnetic particles are easily attracted toward a high magnetic field gradient. Selection of a magnetic field source, which produces a magnetic field gradient large enough to detect a defect in a test sample or component, is an important factor in magnetic particle inspection. In this work a finite element method (FEM) has beenmore » employed for numerical calculation of the MPI simulation technique. The FEM method is known to be suitable for complicated geometries such as defects in samples. This thesis describes the research that is aimed at providing a quantitative scientific basis for magnetic particle inspection. A new FEM solver for MPI simulation has been developed in this research for not only nonlinear reversible permeability materials but also irreversible hysteresis materials that are described by the Jiles-Atherton model. The material is assumed to have isotropic ferromagnetic properties in this research (i.e., the magnetic properties of the material are identical in all directions in a single crystal). In the research, with a direct current field mode, an MPI situation has been simulated to measure the estimated volume of magnetic particles around defect sites before and after removing any external current fields. Currently, this new MPI simulation package is limited to solving problems with the single current source from either a solenoid or an axial directional current rod.« less

Single particle mass spectral signatures from vehicle exhaust particles and the source apportionment of on-line PM2.5 by single particle aerosol mass spectrometry.

PubMed

Yang, Jian; Ma, Shexia; Gao, Bo; Li, Xiaoying; Zhang, Yanjun; Cai, Jing; Li, Mei; Yao, Ling'ai; Huang, Bo; Zheng, Mei

2017-09-01

In order to accurately apportion the many distinct types of individual particles observed, it is necessary to characterize fingerprints of individual particles emitted directly from known sources. In this study, single particle mass spectral signatures from vehicle exhaust particles in a tunnel were performed. These data were used to evaluate particle signatures in a real-world PM 2.5 apportionment study. The dominant chemical type originating from average positive and negative mass spectra for vehicle exhaust particles are EC species. Four distinct particle types describe the majority of particles emitted by vehicle exhaust particles in this tunnel. Each particle class is labeled according to the most significant chemical features in both average positive and negative mass spectral signatures, including ECOC, NaK, Metal and PAHs species. A single particle aerosol mass spectrometry (SPAMS) was also employed during the winter of 2013 in Guangzhou to determine both the size and chemical composition of individual atmospheric particles, with vacuum aerodynamic diameter (d va ) in the size range of 0.2-2μm. A total of 487,570 particles were chemically analyzed with positive and negative ion mass spectra and a large set of single particle mass spectra was collected and analyzed in order to identify the speciation. According to the typical tracer ions from different source types and classification by the ART-2a algorithm which uses source fingerprints for apportioning ambient particles, the major sources of single particles were simulated. Coal combustion, vehicle exhaust, and secondary ion were the most abundant particle sources, contributing 28.5%, 17.8%, and 18.2%, respectively. The fraction with vehicle exhaust species particles decreased slightly with particle size in the condensation mode particles. Copyright © 2017 Elsevier B.V. All rights reserved.

Droplet activation, separation, and compositional analysis: laboratory studies and atmospheric measurements

NASA Astrophysics Data System (ADS)

Hiranuma, N.; Kohn, M.; Pekour, M. S.; Nelson, D. A.; Shilling, J. E.; Cziczo, D. J.

2011-10-01

Droplets produced in a cloud condensation nuclei chamber (CCNC) as a function of supersaturation have been separated from unactivated aerosol particles using counterflow virtual impaction. Residual material after droplets were evaporated was chemically analyzed with an Aerodyne Aerosol Mass Spectrometer (AMS) and the Particle Analysis by Laser Mass Spectrometry (PALMS) instrument. Experiments were initially conducted to verify activation conditions for monodisperse ammonium sulfate particles and to determine the resulting droplet size distribution as a function of supersaturation. Based on the observed droplet size, the counterflow virtual impactor cut-size was set to differentiate droplets from unactivated interstitial particles. Validation experiments were then performed to verify that only droplets with sufficient size passed through the counterflow virtual impactor for subsequent analysis. A two-component external mixture of monodisperse particles was also exposed to a supersaturation which would activate one of the types (hygroscopic salts) but not the other (polystyrene latex spheres or adipic acid). The mass spectrum observed after separation indicated only the former, validating separation of droplets from unactivated particles. Results from ambient measurements using this technique and AMS analysis were inconclusive, showing little chemical differentiation between ambient aerosol and activated droplet residuals, largely due to low signal levels. When employing as single particle mass spectrometer for compositional analysis, however, we observed enhancement of sulfate in droplet residuals.

Dynamic fracture behavior of single and contacting Poly(methyl methacrylate) particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parab, Niranjan D.; Guo, Zherui; Hudspeth, Matthew C.

Fracture behaviors of single, two, and multiple contacting spherical Poly (methyl methacrylate) (PMMA) particles were recorded using high speed synchrotron X-ray phase contrast imaging. A miniaturized Kolsky bar setup was used to apply dynamic compressive loading on the PMMA particles. In both single and two particle experiments, cracking initiated near the center of the particles and propagated towards the contacts. The crack bifurcated near the contact points for single particle experiments, thus forming conical fragments. The crack bifurcation and subsequent conical fragment formation was observed only at the particle-particle contact for two particle experiments. The particles were observed to fracturemore » in hemispherical fragments normal to the contact plane in the multiparticle experiments. The observed failure mechanisms strongly suggest that the maximum tensile stress near the center of the particle is the critical parameter governing fracture of the particles. Moreover, the compressive stress under the contact areas led to the bifurcation and subsequent conical fragment formation.« less

Dynamic fracture behavior of single and contacting Poly(methyl methacrylate) particles

DOE PAGES

Parab, Niranjan D.; Guo, Zherui; Hudspeth, Matthew C.; ...

2017-09-19

Fracture behaviors of single, two, and multiple contacting spherical Poly (methyl methacrylate) (PMMA) particles were recorded using high speed synchrotron X-ray phase contrast imaging. A miniaturized Kolsky bar setup was used to apply dynamic compressive loading on the PMMA particles. In both single and two particle experiments, cracking initiated near the center of the particles and propagated towards the contacts. The crack bifurcated near the contact points for single particle experiments, thus forming conical fragments. The crack bifurcation and subsequent conical fragment formation was observed only at the particle-particle contact for two particle experiments. The particles were observed to fracturemore » in hemispherical fragments normal to the contact plane in the multiparticle experiments. The observed failure mechanisms strongly suggest that the maximum tensile stress near the center of the particle is the critical parameter governing fracture of the particles. Moreover, the compressive stress under the contact areas led to the bifurcation and subsequent conical fragment formation.« less

Long-term airborne black carbon measurements on a Lufthansa passenger aircraft

NASA Astrophysics Data System (ADS)

Ditas, Jeannine; Su, Hang; Scharffe, Dieter; Wang, Siwen; Zhang, Yuxuan; Brenninkmeijer, Carl; Pöschl, Ulrich; Cheng, Yafang

2016-04-01

Aerosol particles containing black carbon are the most absorbing component of incoming solar radiation and exert a significant positive radiative forcing thus forming next to CO² the strongest component of current global warming (Bond, 2013). Nevertheless, the role of black carbon particles and especially their complex interaction with clouds needs further research which is hampered by the limited experimental data, especially observations in the free and upper troposphere, and in the UTLS (upper troposphere and lower stratosphere). Many models underestimate the global atmospheric absorption attributable to black carbon by a factor of almost 3 (Bond, 2013). In August 2014, a single particle soot photometer was included in the extensive scientific payload of the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) project. CARIBIC is in operation since 1997 (with an interruption for 2002-2005) and carries out systematic observations at 10-12 km altitude. For this a special air freight container combining different instruments is transported on a monthly basis using a Lufthansa Airbus A340-600 passenger aircraft with destinations from 120°W to 120°E and 10°N to 75°N. The container has equipment for trace gas analyses and sampling and aerosol analyses and sampling and is connected to an inlet system that is part of the aircraft which contains a camera and DOAS remote sensing system. The integration of a single particle soot photometer (SP2) offers the possibility for the first long-term measurement of global distribution of black carbon and so far flights up to November 2015 have been conducted with more than 400 flight hours. So far the SP2 measurements have been analysed for flights over four continents from Munich to San Francisco, Sao Paulo, Tokyo, Beijing, Cape Town, Los Angeles and Hong Kong). The first measurements show promising results of black carbon measurements. Background concentrations in the UTLS have been determined. Beside a general distribution of number and mass of black carbon particles, single peak events were detected with an up to 20 times higher concentration. High concentration plumes have been observed continuously over a range of 10,000 km. Interestingly, the first measurements show also a lower amount of black carbon mass in the tropics compared to the mid latitude northern hemisphere. References CARIBIC: www.caribic-atmospheric.com / www.caribic-atmospheric.org / www.caribic.de Bond, T. C., et al. (2013), Bounding the role of black carbon in the climate system: A scientific assessment, J. Geophys. Res. Atmos., 118, 5380-5552, doi:10.1002/jgrd.50171

System design of a 1 MW north-facing, solid particle receiver

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christian, J.; Ho, C.

Falling solid particle receivers (SPR) utilize small particles as a heat collecting medium within a cavity receiver structure. The components required to operate an SPR include the receiver (to heat the particles), bottom hopper (to catch the falling particles), particle lift elevator (to lift particles back to the top of the receiver), top hopper (to store particles before being dropped through the receiver), and ducting. In addition to the required components, there are additional features needed for an experimental system. These features include: a support structure to house all components, calibration panel to measure incident radiation, cooling loops, and sensorsmore » (flux gages, thermocouples, pressure gages). Each of these components had to be designed to withstand temperatures ranging from ambient to 700 °C. Thermal stresses from thermal expansion become a key factor in these types of high temperature systems. The SPR will be housing ~3000 kg of solid particles. The final system will be tested at the National Solar Thermal Test Facility in Albuquerque, NM.« less

System design of a 1 MW north-facing, solid particle receiver

DOE PAGES

Christian, J.; Ho, C.

2015-05-01

Falling solid particle receivers (SPR) utilize small particles as a heat collecting medium within a cavity receiver structure. The components required to operate an SPR include the receiver (to heat the particles), bottom hopper (to catch the falling particles), particle lift elevator (to lift particles back to the top of the receiver), top hopper (to store particles before being dropped through the receiver), and ducting. In addition to the required components, there are additional features needed for an experimental system. These features include: a support structure to house all components, calibration panel to measure incident radiation, cooling loops, and sensorsmore » (flux gages, thermocouples, pressure gages). Each of these components had to be designed to withstand temperatures ranging from ambient to 700 °C. Thermal stresses from thermal expansion become a key factor in these types of high temperature systems. The SPR will be housing ~3000 kg of solid particles. The final system will be tested at the National Solar Thermal Test Facility in Albuquerque, NM.« less

Studies in Three Phase Gas-Liquid Fluidised Systems

NASA Astrophysics Data System (ADS)

Awofisayo, Joyce Ololade

1992-01-01

Available from UMI in association with The British Library. The work is a logical continuation of research started at Aston some years ago when studies were conducted on fermentations in bubble columns. The present work highlights typical design and operating problems that could arise in such systems as waste water, chemical, biochemical and petroleum operations involving three-phase, gas-liquid -solid fluidisation; such systems are in increasing use. It is believed that this is one of few studies concerned with "true" three-phase, gas-liquid-solid fluidised systems, and that this work will contribute significantly to closing some of the gaps in knowledge in this area. The research work was experimentally based and involved studies of the hydrodynamic parameters, phase holdups (gas and solid), particle mixing and segregation, and phase flow dynamics (flow regime and circulation patterns). The studies have focused particularly on the solid behaviour and the influence of properties of solids present on the above parameters in three-phase, gas-liquid-solid fluidised systems containing single particle components and those containing binary and ternary mixtures of particles. All particles were near spherical in shape and two particle sizes and total concentration levels were used. Experiments were carried out in two- and three-dimensional bubble columns. Quantitative results are presented in graphical form and are supported by qualitative results from visual studies which are also shown as schematic diagrams and in photographic form. Gas and solid holdup results are compared for air-water containing single, binary and ternary component particle mixtures. It should be noted that the criteria for selection of the materials used are very important if true three-phase fluidisation is to be achieved: this is very evident when comparing the results with those in the literature. The fluid flow and circulation patterns observed were assessed for validation of the generally accepted patterns, and the author believes that the present work provides more accurate insight into the modelling of liquid circulation in bubble columns. The characteristic bubbly flow at low gas velocity in a two-phase system is suppressed in the three-phase system. The degree of mixing within the system is found to be dependent on flow regime, liquid circulation and the ratio of solid phase physical properties.

A novel method to study single-particle dynamics by the resistive pulse technique

NASA Astrophysics Data System (ADS)

Berge, L. I.; Feder, J.; Jøssang, T.

1989-08-01

We have developed a new method, a pressure-reversal technique, which extends the uses of the resistive pulse (Coulter counter) technique to single-particle dynamics. The resistive pulse technique measures the increase in resistance when particles suspended in an electrolyte are transported through a current-carrying aperture. By the new method, the pressure is reversed when a particle exits the pore. A trigger signal, derived from the particle pulses, is used to activate two miniature solenoid valves which serve as pressure switches. In this way, the particle reenters the pore. A single particle flowing back and forth may be studied over a long period of time. The time the particle spends outside the pore between reversals is variable from a few milliseconds to several seconds. We have so far used pore diameters in the range of 3-30 μm. The new technique enables us to study single-particle dissolution and single-particle flow dynamics. The experimental arrangement and the details of the new method are described together with some illustrative measurements.

Microfabricated particle focusing device

DOEpatents

Ravula, Surendra K.; Arrington, Christian L.; Sigman, Jennifer K.; Branch, Darren W.; Brener, Igal; Clem, Paul G.; James, Conrad D.; Hill, Martyn; Boltryk, Rosemary June

2013-04-23

A microfabricated particle focusing device comprises an acoustic portion to preconcentrate particles over large spatial dimensions into particle streams and a dielectrophoretic portion for finer particle focusing into single-file columns. The device can be used for high throughput assays for which it is necessary to isolate and investigate small bundles of particles and single particles.

Tutorial: Radiation Effects in Electronic Systems

NASA Technical Reports Server (NTRS)

Pellish, Jonathan A.

2017-01-01

This tutorial presentation will give an overview of radiation effects in electrical, electronic, and electromechanical (EEE) components as it applies to civilian space systems of varying size and complexity. The natural space environment presents many unique threats to electronic systems regardless of where the systems operate from low-Earth orbit to interplanetary space. The presentation will cover several topics, including: an overview and introduction to the applicable space radiation environments common to a broad range of mission designs; definitions and impacts of effects due to impinging particles in the space environment e.g., total ionizing dose (TID), total non-ionizing dose (TNID), and single-event effects (SEE); and, testing for and evaluation of TID, TNID, and SEE in EEE components.

Observation of pick-up ions in the solar wind: Evidence for the source of the anomalous cosmic ray component?

NASA Technical Reports Server (NTRS)

Hovestadt, D.; Moebius, E.; Klecker, B.; Scholer, M.; Gloeckler, G.; Ipavich, F. M.

1985-01-01

Singly ionized energetic helium has been observed in the solar wind by using the time of flight spectrometer SULEICA on the AMPTE/IRM satellite between September and December, 1984. The energy density spectrum shows a sharp cut off which is strongly correlated with the four fold solar wind bulk energy. The absolute flux of the He(+)ions of about 10000 ion/sq cm.s is present independent of the IPL magnetic field orientation. The most likely source is the neutral helium of the interstellar wind which is ionized by solar UV radiation. It is suggested that these particles represent the source of the anomalous cosmic ray component.

Chemical composition of wildland and agricultural biomass burning particles measured downwind during the BBOP study

NASA Astrophysics Data System (ADS)

Onasch, T. B.; Shilling, J. E.; Wormhoudt, J.; Sedlacek, A. J., III; Fortner, E.; Pekour, M. S.; Chand, D.; Zhou, S.; Collier, S.; Zhang, Q.; Kleinman, L. I.; Lewis, E. R.; Yokelson, R. J.; Adachi, K.; Buseck, P. R.; Freedman, A.; Williams, L. R.

2017-12-01

The Biomass Burning Observation Project (BBOP), a Department of Energy (DOE) sponsored study, measured emissions from wildland fires in the Pacific Northwest and agricultural burns in the Central Southeastern US from the DOE Gulfstream-1 airborne platform over a four month period in 2013. Rapid physical, chemical and optical changes in biomass burning particles were measured downwind (< 3 hours temporally) from wildland fires. The chemical composition of the particulate emissions was characterized using an Aerodyne Soot Particle Aerosol Mass Spectrometer (SP-AMS) and a Single Particle Soot Photometer (SP2) and the measurement results will be presented in the context of the fire location, combustion conditions, and optical property measurements, including extinction and single scattering albedos. The SP-AMS was operated with both laser and resistively heated tungsten vaporizers, alternating between laser on and off. With the laser vaporizer off, the instrument operated as a standard high resolution AMS. Under these sampling conditions, the non-refractory chemical composition, including the level of oxidation (i.e., O:C, H:C, and organic mass/organic carbon ratios, OM:OC), of the biomass burning particles was characterized as a function of the fuel type burned, modified combustion efficiency, and degree of oxidation during downwind transport. With the laser vaporizer on, the SP-AMS was also sensitive to the refractory black carbon (rBC) content, in addition to the non-refractory components. The chemical measurements will be correlated with simultaneous optical measurements. We will also present preliminary results from laboratory studies on tar balls and SP-AMS OA quantification while operating with both laser and tungsten vaporizers.

Methods for forming particles from single source precursors

DOEpatents

Fox, Robert V [Idaho Falls, ID; Rodriguez, Rene G [Pocatello, ID; Pak, Joshua [Pocatello, ID

2011-08-23

Single source precursors are subjected to carbon dioxide to form particles of material. The carbon dioxide may be in a supercritical state. Single source precursors also may be subjected to supercritical fluids other than supercritical carbon dioxide to form particles of material. The methods may be used to form nanoparticles. In some embodiments, the methods are used to form chalcopyrite materials. Devices such as, for example, semiconductor devices may be fabricated that include such particles. Methods of forming semiconductor devices include subjecting single source precursors to carbon dioxide to form particles of semiconductor material, and establishing electrical contact between the particles and an electrode.

New apparatus of single particle trap system for aerosol visualization

NASA Astrophysics Data System (ADS)

Higashi, Hidenori; Fujioka, Tomomi; Endo, Tetsuo; Kitayama, Chiho; Seto, Takafumi; Otani, Yoshio

2014-08-01

Control of transport and deposition of charged aerosol particles is important in various manufacturing processes. Aerosol visualization is an effective method to directly observe light scattering signal from laser-irradiated single aerosol particle trapped in a visualization cell. New single particle trap system triggered by light scattering pulse signal was developed in this study. The performance of the device was evaluated experimentally. Experimental setup consisted of an aerosol generator, a differential mobility analyzer (DMA), an optical particle counter (OPC) and the single particle trap system. Polystylene latex standard (PSL) particles (0.5, 1.0 and 2.0 μm) were generated and classified according to the charge by the DMA. Singly charged 0.5 and 1.0 μm particles and doubly charged 2.0 μm particles were used as test particles. The single particle trap system was composed of a light scattering signal detector and a visualization cell. When the particle passed through the detector, trigger signal with a given delay time sent to the solenoid valves upstream and downstream of the visualization cell for trapping the particle in the visualization cell. The motion of particle in the visualization cell was monitored by CCD camera and the gravitational settling velocity and the electrostatic migration velocity were measured from the video image. The aerodynamic diameter obtained from the settling velocity was in good agreement with Stokes diameter calculated from the electrostatic migration velocity for individual particles. It was also found that the aerodynamic diameter obtained from the settling velocity was a one-to-one function of the scattered light intensity of individual particles. The applicability of this system will be discussed.

Particle-fluid interactions for flow measurements

NASA Technical Reports Server (NTRS)

Berman, N. S.

1973-01-01

Study has been made of the motion of single particle and of group of particles, emphasizing solid particles in gaseous fluid. Velocities of fluid and particle are compared for several conditions of physical interest. Mean velocity and velocity fluctuations are calculated for single particle, and some consideration is given to multiparticle systems.

Analysis of radiation risk from alpha particle component of solar particle events

NASA Technical Reports Server (NTRS)

Cucinotta, F. A.; Townsend, L. W.; Wilson, J. W.; Golightly, M. J.; Weyland, M.

1994-01-01

The solar particle events (SPE) will contain a primary alpha particle component, representing a possible increase in the potential risk to astronauts during an SPE over the often studied proton component. We discuss the physical interactions of alpha particles important in describing the transport of these particles through spacecraft and body shielding. Models of light ion reactions are presented and their effects on energy and linear energy transfer (LET) spectra in shielding discussed. We present predictions of particle spectra, dose, and dose equivalent in organs of interest for SPE spectra typical of those occurring in recent solar cycles. The large events of solar cycle 19 are found to have substantial increase in biological risk from alpha particles, including a large increase in secondary neutron production from alpha particle breakup.

Structure of epsilon15 bacteriophage reveals genome organization and DNA packaging/injection apparatus

NASA Astrophysics Data System (ADS)

Jiang, Wen; Chang, Juan; Jakana, Joanita; Weigele, Peter; King, Jonathan; Chiu, Wah

2006-02-01

The critical viral components for packaging DNA, recognizing and binding to host cells, and injecting the condensed DNA into the host are organized at a single vertex of many icosahedral viruses. These component structures do not share icosahedral symmetry and cannot be resolved using a conventional icosahedral averaging method. Here we report the structure of the entire infectious Salmonella bacteriophage epsilon15 (ref. 1) determined from single-particle cryo-electron microscopy, without icosahedral averaging. This structure displays not only the icosahedral shell of 60 hexamers and 11 pentamers, but also the non-icosahedral components at one pentameric vertex. The densities at this vertex can be identified as the 12-subunit portal complex sandwiched between an internal cylindrical core and an external tail hub connecting to six projecting trimeric tailspikes. The viral genome is packed as coaxial coils in at least three outer layers with ~90 terminal nucleotides extending through the protein core and the portal complex and poised for injection. The shell protein from icosahedral reconstruction at higher resolution exhibits a similar fold to that of other double-stranded DNA viruses including herpesvirus, suggesting a common ancestor among these diverse viruses. The image reconstruction approach should be applicable to studying other biological nanomachines with components of mixed symmetries.

An optical apparatus for rotation and trapping

PubMed Central

Gutiérrez-Medina, Braulio; Andreasson, Johan O. L.; Greenleaf, William J.; LaPorta, Arthur; Block, Steven M.

2010-01-01

We present details of the design, construction and testing of a single-beam optical tweezers apparatus capable of measuring and exerting torque, as well as force, on microfabricated, optically anisotropic particles (an ‘optical torque wrench’). The control of angular orientation is achieved by rotating the linear polarization of a trapping laser with an electro-optic modulator (EOM), which affords improved performance over previous designs. The torque imparted to the trapped particle is assessed by measuring the difference between left- and right-circular components of the transmitted light, and constant torque is maintained by feeding this difference signal back into a custom-designed electronic servo loop. The limited angular range of the EOM (±180°) is extended by rapidly reversing the polarization once a threshold angle is reached, enabling the torque clamp to function over unlimited, continuous rotations at high bandwidth. In addition, we developed particles suitable for rotation in this apparatus using microfabrication techniques. Altogether, the system allows for the simultaneous application of forces (~0.1–100 pN) and torques (~1–10,000 pN nm) in the study of biomolecules. As a proof of principle, we demonstrate how our instrument can be used to study the supercoiling of single DNA molecules. PMID:20627165

Helium-filled soap bubbles tracing fidelity in wall-bounded turbulence

NASA Astrophysics Data System (ADS)

Faleiros, David Engler; Tuinstra, Marthijn; Sciacchitano, Andrea; Scarano, Fulvio

2018-03-01

The use of helium-filled soap bubbles (HFSB) as flow tracers for particle image velocimetry (PIV) and particle tracking velocimetry (PTV) to measure the properties of turbulent boundary layers is investigated in the velocity range from 30 to 50 m/s. The experiments correspond to momentum thickness-based Reynolds numbers of 3300 and 5100. A single bubble generator delivers nearly neutrally buoyant HFSB to seed the air flow developing over the flat plate. The HFSB motion analysis is performed by PTV using single-frame multi-exposure recordings. The measurements yield the local velocity and turbulence statistics. Planar two-component-PIV measurements with micron-sized droplets (DEHS) conducted under the same conditions provide reference data for the quantities of interest. In addition, the behavior of air-filled soap bubbles is studied where the effect of non-neutral buoyancy is more pronounced. The mean velocity profiles as well as the turbulent stresses obtained with HFSB are in good agreement with the flow statistics obtained with DEHS particles. The study illustrates that HFSB tracers can be used to determine the mean velocity and the turbulent fluctuations of turbulent boundary layers above a distance of approximately two bubble diameters from the wall. This work broadens the current range of application of HFSB from external aerodynamics of large-scale-PIV experiments towards wall-bounded turbulence.

Measurements of Size Resolved Organic Particulate Mass Using An On-line Aerosol Mass Spectrometer (ams) Laboratory Validation; Analysis Tool Development; and Interpretation of Field Data

NASA Astrophysics Data System (ADS)

Alfarra, M. R.; Coe, H.; Allan, J. D.; Bower, K. N.; Garforth, A. A.; Canagaratna, M.; Worsnop, D.

The aerosol mass spectrometer (AMS) is a quantitative instrument designed to deliver real-time size resolved chemical composition of the volatile and semi volatile aerosol fractions. The AMS response to a wide range of organic compounds has been exper- imentally characterized, and has been shown to compare well with standard libraries of 70 eV electron impact ionization mass spectra. These results will be presented. Due to the scanning nature of the quadrupole mass spectrometer, the AMS provides averaged composition of ensemble of particles rather than single particle composi- tion. However, the mass spectra measured by AMS are reproducible and similar to those of standard libraries so analysis tools can be developed on large mass spectral libraries that can provide chemical composition information about the type of organic compounds in the aerosol. One such tool is presented and compared with laboratory measurements of single species and mixed component organic particles by the AMS. We will then discuss the applicability of these tools to interpreting field AMS data ob- tained in a range of experiments at different sites in the UK and Canada. The data will be combined with other measurements to show the behaviour of the organic aerosol fraction in urban and sub-urban environments.

Aerosol properties in the upper clouds of Venus from glory observations by the Venus Monitoring Camera (Venus Express mission)

NASA Astrophysics Data System (ADS)

Markiewicz, Wojciech J.; Petrova, Elena V.; Shalygina, Oksana S.

2018-01-01

From the angular positions of the glory features observed on the upper cloud deck of Venus in three VMC channels (at 0.365, 0.513, and 0.965 μm), the dominating sizes of cloud particles and their refractive indices have been retrieved, and their spatial and temporal variations have been analyzed. For this, the phase profiles of brightness were compared to the single-scattering phase functions of particles of different sizes, since diffuse multiple scattering in the clouds does not move the angular positions of the glory, which is produced by the single scattering by cloud particles, but only makes them less pronounced. We presented the measured phase profiles in two ways: they were built for individual images and for individual small regions observed in series of successive images. The analysis of the data of both types has yielded consistent results. The presently retrieved radii of cloud particle average approximately 1.0-1.2 μm (though some values reach 1.4 μm) and demonstrate a variable pattern versus latitude and local solar time (LST). The decrease of particle sizes at high latitudes (down to 0.6 μm at 60°S) earlier found from the 0.965-μm and partly 0.365-μm data has been definitely confirmed in the analysis of the data of all three channels considered. To obtain the consistent estimates of particle sizes from the UV glory maximum and minimum positions, we have to vary the effective variance of the particle sizes, while it was fixed constant in our previous studies. The twofold increase of this parameter (from 0.07 to 0.14) diminishes the estimates of particle sizes by 10-15%, while the effect on the retrieved refractive index is negligible. The obtained estimates of the refractive index are more or less uniformly distributed over the covered latitude and LST ranges, and most of them are higher than those of concentrated sulfuric acid solution. This confirms our previous result obtained only at 0.965 μm, and now we may state that the cases of a relatively high real part of the refractive index are often observed for the 1-μm mode of cloud particles on Venus. Consequently, an additional component with a high value of the refractive index is required to be present in the cloud droplets. We suggest that this component is in small submicron particles; during the condensation process, they become incorporated into sulfuric acid droplets, which results in forming the complex UV absorbing particles with an increased refractive index. We suppose that this material can be ferric chloride that is one of the candidates for the so-called unknown UV absorber in the upper clouds of Venus.

Dosimetry of heavy ions by use of CCD detectors

NASA Technical Reports Server (NTRS)

Schott, J. U.

1994-01-01

The design and the atomic composition of Charge Coupled Devices (CCD's) make them unique for investigations of single energetic particle events. As detector system for ionizing particles they detect single particles with local resolution and near real time particle tracking. In combination with its properties as optical sensor, particle transversals of single particles are to be correlated to any objects attached to the light sensitive surface of the sensor by simple imaging of their shadow and subsequent image analysis of both, optical image and particle effects, observed in affected pixels. With biological objects it is possible for the first time to investigate effects of single heavy ions in tissue or extinguished organs of metabolizing (i.e. moving) systems with a local resolution better than 15 microns. Calibration data for particle detection in CCD's are presented for low energetic protons and heavy ions.

icpTOF: a new way for the detection of synthetic nanoparticles in environmental systems

NASA Astrophysics Data System (ADS)

Borovinskaya, Olga; Tanner, Martin; Böhme, Steffi; Gondikas, Andreas

2016-04-01

Tons of engineered nanoparticles are yearly released into the environment as a result of human activity and utilization of nano-containing products. Driven by demand and innovations, the production volumes of nanomaterials are predicted to grow further and already in 2020 will reach >500000 tons [1]. The current challenge faced by society is the lack of information about the fate, behavior, and implications of nanomaterials. This gap has to be filled in order to develop an appropriate strategy for the regulation of nanotechnologies. This is not a simple task because we are still unable to detect and monitor nanoparticles once they have been released into the environment. The list of analytical techniques which can be applied for nanoparticle detection in complex media and at environmentally relevant concentrations (ppt-ppb) is very short and for most of the studies complementary approaches are applied. Single particle (sp)-ICP-MS is a new technique which provides an easy and routinely applied way to quantitatively determine size and number concentration of metal-containing nanoparticles [2]. Moreover, element-specific detection makes sp-ICP-MS more tolerant to high levels of natural background (e.g. organic matter, bacteria). The measurement of single particles implies the detection of extremely short signals (100-500 μm) and requires sensitive and fast instrumentation. Sequentially scanning instruments based on quadrupole or sector-field technology cannot accurately measure more than one isotope per particle and determine elemental composition of single particles. A new icpTOF mass spectrometer (TOFWERK AG, Switzerland) provides simultaneous detection over the whole mass range of elements at μs-time resolution and with >3000 mass resolving power. These unique features render the determination of multi-element composition of single nanoparticles possible [3]. This additional information is extremely valuable to study chemical transformations of particles once they have entered the real ecosystem. Besides, element ratios of single particles can be used as a specific merit for the identification of synthetic nanoparticles in the presence of naturally occurring particulate background [4]. In addition to higher mass resolving power, the instrument is equipped with a collision/reaction cell, which helps to improve detection limits for elements suffering from interferences (e.g. Fe, Ti, P, S). The icpTOF performance will be shown in combination with different sample introduction systems, including novel discrete microdroplet introduction. The single droplet introduction approach enables particle quantification without particulate reference materials and significantly simplifies the analysis. The advantages of fast simultaneous detection for the characterization of multi-component nanoparticles in environmental media will be demonstrated on several studies. [1] Nanoscience and Nanotechnologies: Nanoscience and nanotechnologies: opportunities and uncertainties, Final Report. Royal Society: London, 2004 [2] Degueldre et al. (2003), Coll. Surf. A, 217, 137-142. [3] Borovinskaya et al. (2014), Anal. Chem, 86, 8142-8148. [4] Von der Kammer et al. (2012), Env. Tox. and Chem., 31, 32-49.

Unmelted meteoritic debris in the Late Pliocene iridium anomaly - Evidence for the ocean impact of a nonchondritic asteroid

NASA Technical Reports Server (NTRS)

Kyte, F. T.; Brownlee, D. E.

1985-01-01

Ir-bearing particles have been recovered from two piston cores in the Antarctic Basin in the southeastern Pacific. In core E13-3, the particles closely correspond to the Late Pliocene Ir anomaly and have a fluence of about 100 mg/cm sq. In core E13-4, 120 km to the southwest, the particle fluence is about 4 mg/cm sq. Particles with diameters from 0.5 to 4 mm contain at least 35 percent of the Ir in this horizon. Three types of particles have been identified: (1) vesicular, (2) basaltic, and (3) metal. The vesicular particles appear to be shock-melted debris derived from the oceanic impact of a howarditic asteroid containing a minor metal component. These particles have recrystallized from a melt and impact into the ocean has resulted in the incorporation of Na, K, Cl, and radiogenic Sr from the ocean water target. The basaltic clasts appear to be unmelted fragments of the original asteroid which may have separated from the main body prior to impact. Combined vesicular and basaltic particles are believed to have formed by collisions in the debris cloud. Estimates of the diameter of the projectile range from 100 to 500 m. By many orders of magnitude, this is the most massive achondrite sampled by a single meteorite fall.

Black light photography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lisin, M.A.

1996-11-01

Black light photography of fluorescent penetrant and wet fluorescent magnetic particle indications can yield spectacular and useful results. The technique provides a lasting record of a flaw`s severity and location, as well as its physical relation to other components and important features. The procedures are easily learned and do not require sophisticated apparatus. In fact, equipment costs can often be justified on the basis of a single application. Using the techniques described in this article, black light photography can be a cost-effective, informative NDT tool.

Electronic structure studies of La2CuO4

NASA Astrophysics Data System (ADS)

Wachs, A. L.; Turchi, P. E. A.; Jean, Y. C.; Wetzler, K. H.; Howell, R. H.; Fluss, M. J.; Harshman, D. R.; Remeika, J. P.; Cooper, A. S.; Fleming, R. M.

1988-07-01

We report results of positron-electron momentum-distribution measurements of single-crystal La2CuO4 using two-dimensional angular correlation of positron-annihilation-radiation techniques. The data contain two components: a large (~85%), isotropic corelike electron contribution and a remaining, anisotropic valence-electron contribution modeled using a linear combination of atomic orbitals-molecular orbital method and a localized ion scheme, within the independent-particle model approximation. This work suggests a ligand-field Hamiltonian to be justified for describing the electronic properties of perovskite materials.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forno, Massimo Dal; Department of Engineering and Architecture, University of Trieste, Trieste; Craievich, Paolo

The front-end injection systems of the FERMI@Elettra linac produce high brightness electron beams that define the performance of the Free Electron Laser. The photoinjector mainly consists of the radiofrequency (rf) gun and of two S-band rf structures which accelerate the beam. Accelerating structures endowed with a single feed coupler cause deflection and degradation of the electron beam properties, due to the asymmetry of the electromagnetic field. In this paper, a new type of single feed structure with movable short-circuit is proposed. It has the advantage of having only one waveguide input, but we propose a novel design where the dipolarmore » component is reduced. Moreover, the racetrack geometry allows to reduce the quadrupolar component. This paper presents the microwave design and the analysis of the particle motion inside the linac. A prototype has been machined at the Elettra facility to verify the new coupler design and the rf field has been measured by adopting the bead-pull method. The results are here presented, showing good agreement with the expectations.« less

Infectious mutants of cassava latent virus generated in vivo from intact recombinant DNA clones containing single copies of the genome.

PubMed Central

Stanley, J; Townsend, R

1986-01-01

Intact recombinant DNAs containing single copies of either component of the cassava latent virus genome can elicit infection when mechanically inoculated to host plants in the presence of the appropriate second component. Characterisation of infectious mutant progeny viruses, by analysis of virus-specific supercoiled DNA intermediates, indicates that most if not all of the cloning vector has been deleted, achieved at least in some cases by intermolecular recombination in vivo between DNAs 1 and 2. Significant rearrangements within the intergenic region of DNA 2, predominantly external to the common region, can be tolerated without loss of infectivity suggesting a somewhat passive role in virus multiplication for the sequences in question. Although packaging constraints might impose limits on the amount of DNA within geminate particles, isolation of an infectious coat protein mutant defective in virion production suggests that packaging is not essential for systemic spread of the viral DNA. Images PMID:2875435

Single-event and total-dose effects in geo-stationary transfer orbit during solar-activity maximum period measured by the Tsubasa satellite

NASA Astrophysics Data System (ADS)

Koshiishi, H.; Kimoto, Y.; Matsumoto, H.; Goka, T.

The Tsubasa satellite developed by the Japan Aerospace Exploration Agency was launched in Feb 2002 into Geo-stationary Transfer Orbit GTO Perigee 500km Apogee 36000km and had been operated well until Sep 2003 The objective of this satellite was to verify the function of commercial parts and new technologies of bus-system components in space Thus the on-board experiments were conducted in the more severe radiation environment of GTO rather than in Geo-stationary Earth Orbit GEO or Low Earth Orbit LEO The Space Environment Data Acquisition equipment SEDA on board the Tsubasa satellite had the Single-event Upset Monitor SUM and the DOSimeter DOS to evaluate influences on electronic devices caused by radiation environment that was also measured by the particle detectors of the SEDA the Standard DOse Monitor SDOM for measurements of light particles and the Heavy Ion Telescope HIT for measurements of heavy ions The SUM monitored single-event upsets and single-event latch-ups occurred in the test sample of two 64-Mbit DRAMs The DOS measured accumulated radiation dose at fifty-six locations in the body of the Tsubasa satellite Using the data obtained by these instruments single-event and total-dose effects in GTO during solar-activity maximum period especially their rapid changes due to solar flares and CMEs in the region from L 1 1 through L 11 is discussed in this paper

Chemical composition and mixing-state of ice residuals sampled within mixed phase clouds

NASA Astrophysics Data System (ADS)

Ebert, M.; Worringen, A.; Benker, N.; Mertes, S.; Weingartner, E.; Weinbruch, S.

2010-10-01

During an intensive campaign at the high alpine research station Jungfraujoch, Switzerland, in February/March 2006 ice particle residuals within mixed-phase clouds were sampled using the Ice-counterflow virtual impactor (Ice-CVI). Size, morphology, chemical composition, mineralogy and mixing state of the ice residual and the interstitial (i.e., non-activated) aerosol particles were analyzed by scanning and transmission electron microscopy. Ice nuclei (IN) were identified from the significant enrichment of particle groups in the ice residual (IR) samples relative to the interstitial aerosol. In terms of number lead-bearing particles are enriched by a factor of approximately 25, complex internal mixtures with silicates or metal oxides as major components by a factor of 11, and mixtures of secondary aerosol and soot (C-O-S particles) by a factor of 2. Other particle groups (sulfates, sea salt, Ca-rich particles, external silicates) observed in the ice-residual samples cannot be assigned unambiguously as IN. Between 9 and 24% of all IR are Pb-bearing particles. Pb was found as major component in around 10% of these particles (PbO, PbCl2). In the other particles, Pb was found as some 100 nm sized agglomerates consisting of 3-8 nm sized primary particles (PbS, elemental Pb). C-O-S particles are present in the IR at an abundance of 17-27%. The soot component within these particles is strongly aged. Complex internal mixtures occur in the IR at an abundance of 9-15%. Most IN identified at the Jungfraujoch station are internal mixtures containing anthropogenic components (either as main or minor constituent), and it is concluded that admixture of the anthropogenic component is responsible for the increased IN efficiency within mixed phase clouds. The mixing state appears to be a key parameter for the ice nucleation behaviour that cannot be predicted from the separate components contained within the individual particles.

Bilocal current densities and mean trajectories in a Young interferometer with two Gaussian slits and two detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Withers, L. P., E-mail: lpwithers@mitre.org; Narducci, F. A., E-mail: francesco.narducci@navy.mil

2015-06-15

The recent single-photon double-slit experiment of Steinberg et al., based on a weak measurement method proposed by Wiseman, showed that, by encoding the photon’s transverse momentum behind the slits into its polarization state, the momentum profile can subsequently be measured on average, from a difference of the separated fringe intensities for the two circular polarization components. They then integrated the measured average velocity field, to obtain the average trajectories of the photons enroute to the detector array. In this paper, we propose a modification of their experiment, to demonstrate that the average particle velocities and trajectories change when the modemore » of detection changes. The proposed experiment replaces a single detector by a pair of detectors with a given spacing between them. The pair of detectors is configured so that it is impossible to distinguish which detector received the particle. The pair of detectors is then analogous to the simple pair of slits, in that it is impossible to distinguish which slit the particle passed through. To establish the paradoxical outcome of the modified experiment, the theory and explicit three-dimensional formulas are developed for the bilocal probability and current densities, and for the average velocity field and trajectories as the particle wavefunction propagates in the volume of space behind the Gaussian slits. Examples of these predicted results are plotted. Implementation details of the proposed experiment are discussed.« less

Towards a high performance geometry library for particle-detector simulations

DOE PAGES

Apostolakis, J.; Bandieramonte, M.; Bitzes, G.; ...

2015-05-22

Thread-parallelization and single-instruction multiple data (SIMD) ”vectorisation” of software components in HEP computing has become a necessity to fully benefit from current and future computing hardware. In this context, the Geant-Vector/GPU simulation project aims to re-engineer current software for the simulation of the passage of particles through detectors in order to increase the overall event throughput. As one of the core modules in this area, the geometry library plays a central role and vectorising its algorithms will be one of the cornerstones towards achieving good CPU performance. Here, we report on the progress made in vectorising the shape primitives, asmore » well as in applying new C++ template based optimizations of existing code available in the Geant4, ROOT or USolids geometry libraries. We will focus on a presentation of our software development approach that aims to provide optimized code for all use cases of the library (e.g., single particle and many-particle APIs) and to support different architectures (CPU and GPU) while keeping the code base small, manageable and maintainable. We report on a generic and templated C++ geometry library as a continuation of the AIDA USolids project. As a result, the experience gained with these developments will be beneficial to other parts of the simulation software, such as for the optimization of the physics library, and possibly to other parts of the experiment software stack, such as reconstruction and analysis.« less

Towards a high performance geometry library for particle-detector simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Apostolakis, J.; Bandieramonte, M.; Bitzes, G.

Thread-parallelization and single-instruction multiple data (SIMD) ”vectorisation” of software components in HEP computing has become a necessity to fully benefit from current and future computing hardware. In this context, the Geant-Vector/GPU simulation project aims to re-engineer current software for the simulation of the passage of particles through detectors in order to increase the overall event throughput. As one of the core modules in this area, the geometry library plays a central role and vectorising its algorithms will be one of the cornerstones towards achieving good CPU performance. Here, we report on the progress made in vectorising the shape primitives, asmore » well as in applying new C++ template based optimizations of existing code available in the Geant4, ROOT or USolids geometry libraries. We will focus on a presentation of our software development approach that aims to provide optimized code for all use cases of the library (e.g., single particle and many-particle APIs) and to support different architectures (CPU and GPU) while keeping the code base small, manageable and maintainable. We report on a generic and templated C++ geometry library as a continuation of the AIDA USolids project. As a result, the experience gained with these developments will be beneficial to other parts of the simulation software, such as for the optimization of the physics library, and possibly to other parts of the experiment software stack, such as reconstruction and analysis.« less

Relative optically stimulated luminescence and thermoluminescence efficiencies of Al2O3:C dosimeters to heavy charged particles with energies relevant to space and radiotherapy dosimetry

NASA Astrophysics Data System (ADS)

Sawakuchi, G. O.; Yukihara, E. G.; McKeever, S. W. S.; Benton, E. R.; Gaza, R.; Uchihori, Y.; Yasuda, N.; Kitamura, H.

2008-12-01

This article presents a comprehensive characterization of the thermoluminescence (TL) and optically stimulated luminescence (OSL) relative luminescence efficiencies of carbon-doped aluminum (Al2O3:C) for heavy charged particles (HCPs) with atomic numbers ranging from 1 (proton) to 54 (xenon) and energies ranging from 7 to 1000 MeV/u, and investigates the dependence of the Al2O3:C response on experimental conditions. Relative luminescence efficiency values are presented for 19 primary charge/energy combinations, plus 31 additional charge/energy combinations obtained by introducing absorbers in the primary beam. Our results show that for energies of hundreds of MeV/u the data can be described by a single curve of relative luminescence efficiency versus linear energy transfer (LET). This information is needed to compensate for the reduced OSL efficiency to high-LET particles in such applications as space dosimetry. For lower energies, the relative luminescence efficiency as function of LET cannot be described by a single curve; instead, it separates into different components corresponding to different particles. We also present data on the low-LET dose response of Al2O3:C, measured under the same experimental conditions in which the relative luminescence efficiencies to HCPs were obtained, providing information relevant to future theoretical investigations of HCP energy deposition and luminescence production in Al2O3:C.

The dendritic effect and magnetic permeability in dendron coated nickel and manganese zinc ferrite nanoparticles.

PubMed

Jishkariani, Davit; Lee, Jennifer D; Yun, Hongseok; Paik, Taejong; Kikkawa, James M; Kagan, Cherie R; Donnio, Bertrand; Murray, Christopher B

2017-09-28

The collective magnetic properties of nanoparticle (NP) solid films are greatly affected by inter-particle dipole-dipole interactions and therefore the proximity of the neighboring particles. In this study, a series of dendritic ligands (generations 0 to 3, G0-G3) have been designed and used to cover the surface of magnetic NPs to control the spacings between the NP components in single lattices. The dendrons of different generations introduced here were based on the 2,2-bis(hydroxymethyl)propionic acid (Bis-MPA) scaffold and equipped with an appropriate surface binding group at one end and several fatty acid segments at the other extremity. The surface of the NPs was then modified by partial ligand exchange between the primary stabilizing surfactants and the new dendritic wedges. It was shown that this strategy permitted very precise tuning of inter-particle spacings in the range of 2.9-5.0 nm. As expected, the increase in the inter-particle spacings reduced the dipole-dipole interactions between magnetic NPs and therefore allowed changes in their magnetic permeability. The dendron size and inter-particle distance dependence was studied to reveal the dendritic effect and identify the optimal geometry and generation.

Sub-grid drag models for horizontal cylinder arrays immersed in gas-particle multiphase flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarkar, Avik; Sun, Xin; Sundaresan, Sankaran

2013-09-08

Immersed cylindrical tube arrays often are used as heat exchangers in gas-particle fluidized beds. In multiphase computational fluid dynamics (CFD) simulations of large fluidized beds, explicit resolution of small cylinders is computationally infeasible. Instead, the cylinder array may be viewed as an effective porous medium in coarse-grid simulations. The cylinders' influence on the suspension as a whole, manifested as an effective drag force, and on the relative motion between gas and particles, manifested as a correction to the gas-particle drag, must be modeled via suitable sub-grid constitutive relationships. In this work, highly resolved unit-cell simulations of flow around an arraymore » of horizontal cylinders, arranged in a staggered configuration, are filtered to construct sub-grid, or `filtered', drag models, which can be implemented in coarse-grid simulations. The force on the suspension exerted by the cylinders is comprised of, as expected, a buoyancy contribution, and a kinetic component analogous to fluid drag on a single cylinder. Furthermore, the introduction of tubes also is found to enhance segregation at the scale of the cylinder size, which, in turn, leads to a reduction in the filtered gas-particle drag.« less

Tabletop Traffic Jams: Modeling Traffic Jams using Self Propelled Particles

NASA Astrophysics Data System (ADS)

Yadav, Vikrant; Kudrolli, Arshad

2015-03-01

We model behavior of traffic using Self Propelled Particles (SPPs). Granular rods with asymmetric mass distribution confined to move in a circular channel on a vibrated substrate and interact with each other through inelastic collision serve as our model vehicle. Motion of a single vehicle is observed to be composed of 2 parts, a linear velocity in the direction of lighter end of particle and a non-Gaussian random velocity. We find that the collective mean speed of the SPPs is constant over a wide range of line densities before decreasing rapidly as the maximum packing is approached indicating the spontaneous formation of Phantom jams. This decrease in speed is observed to be far greater than any small differences in the mean drift speed of individual SPPs , and occurs as the collision frequency between SPPs increase exponentially with line density. However the random velocity component of SPPs remain super-diffusive over entire range of line densities. While the collective motion at low densities is characterized by caravan following behind the slowest particle leading to clustering, at higher densities we see formation of jamming waves travelling in direction opposite to that of motion of particles.

Saha equation, single and two particle states

NASA Technical Reports Server (NTRS)

Kraeft, W. D.; Girardeau, M. D.; Strege, B.

1990-01-01

Single- and two-particle properties in a dense plasma are discussed in connection with their role in the mass action law for a partially ionized plasma. The two-particle-bound states are nearly density independent, while the continuum is essentially shifted. The single-particle states are damped, and their energy has a negative shift and a parabolic behavior for small momenta.

Negative DC corona discharge current characteristics in a flowing two-phase (air + suspended smoke particles) fluid

NASA Astrophysics Data System (ADS)

Berendt, Artur; Domaszka, Magdalena; Mizeraczyk, Jerzy

2017-04-01

The electrical characteristics of a steady-state negative DC corona discharge in a two-phase fluid (air with suspended cigarette smoke particles) flowing along a chamber with a needle-to-plate electrode arrangement were experimentally investigated. The two-phase flow was transverse in respect to the needle-to-plate axis. The velocity of the transverse two-phase flow was limited to 0.8 m/s, typical of the electrostatic precipitators. We found that three discharge current modes of the negative corona exist in the two-phase (air + smoke particles) fluid: the Trichel pulses mode, the "Trichel pulses superimposed on DC component" mode and the DC component mode, similarly as in the corona discharge in air (a single-phase fluid). The shape of Trichel pulses in the air + suspended particles fluid is similar to that in air. However, the Trichel pulse amplitudes are higher than those in "pure" air while their repetition frequency is lower. As a net consequence of that the averaged corona discharge current in the two-phase fluid is lower than in "pure" air. It was also found that the average discharge current decreases with increasing suspended particle concentration. The calculations showed that the dependence of the average negative corona current (which is a macroscopic corona discharge parameter) on the particle concentration can be explained by the particle-concentration dependencies of the electric charge of Trichel pulse and the repetition frequency of Trichel pulses, both giving a microscopic insight into the electrical phenomena in the negative corona discharge. Our investigations showed also that the average corona discharge current in the two-phase fluid is almost unaffected by the transverse fluid flow up to a velocity of 0.8 m/s. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomáš Hoder

Coupling discrete and continuum concentration particle models for multiscale and hybrid molecular-continuum simulations

DOE PAGES

Petsev, Nikolai Dimitrov; Leal, L. Gary; Shell, M. Scott

2017-12-21

Hybrid molecular-continuum simulation techniques afford a number of advantages for problems in the rapidly burgeoning area of nanoscale engineering and technology, though they are typically quite complex to implement and limited to single-component fluid systems. We describe an approach for modeling multicomponent hydrodynamic problems spanning multiple length scales when using particle-based descriptions for both the finely-resolved (e.g. molecular dynamics) and coarse-grained (e.g. continuum) subregions within an overall simulation domain. This technique is based on the multiscale methodology previously developed for mesoscale binary fluids [N. D. Petsev, L. G. Leal, and M. S. Shell, J. Chem. Phys. 144, 84115 (2016)], simulatedmore » using a particle-based continuum method known as smoothed dissipative particle dynamics (SDPD). An important application of this approach is the ability to perform coupled molecular dynamics (MD) and continuum modeling of molecularly miscible binary mixtures. In order to validate this technique, we investigate multicomponent hybrid MD-continuum simulations at equilibrium, as well as non-equilibrium cases featuring concentration gradients.« less

Coupling discrete and continuum concentration particle models for multiscale and hybrid molecular-continuum simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petsev, Nikolai Dimitrov; Leal, L. Gary; Shell, M. Scott

Hybrid molecular-continuum simulation techniques afford a number of advantages for problems in the rapidly burgeoning area of nanoscale engineering and technology, though they are typically quite complex to implement and limited to single-component fluid systems. We describe an approach for modeling multicomponent hydrodynamic problems spanning multiple length scales when using particle-based descriptions for both the finely-resolved (e.g. molecular dynamics) and coarse-grained (e.g. continuum) subregions within an overall simulation domain. This technique is based on the multiscale methodology previously developed for mesoscale binary fluids [N. D. Petsev, L. G. Leal, and M. S. Shell, J. Chem. Phys. 144, 84115 (2016)], simulatedmore » using a particle-based continuum method known as smoothed dissipative particle dynamics (SDPD). An important application of this approach is the ability to perform coupled molecular dynamics (MD) and continuum modeling of molecularly miscible binary mixtures. In order to validate this technique, we investigate multicomponent hybrid MD-continuum simulations at equilibrium, as well as non-equilibrium cases featuring concentration gradients.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ali, S.; Bukhari, S.; Department of Physics, The University of Azad Jammu and Kashmir, Muzaffarabad 13100, Azad Kashmir

Keeping in view the kinetic treatment for plasma particles, the electrostatic twisted dust-acoustic (DA) and dust-ion-acoustic (DIA) waves are investigated in a collisionless unmagnetized multi-component dusty plasma, whose constituents are the electrons, singly ionized positive ions, and negatively charged massive dust particulates. With this background, the Vlasov–Poisson equations are coupled together to derive a generalized dielectric constant by utilizing the Laguerre-Gaussian perturbed distribution function and electrostatic potential in the paraxial limit. The dispersion and damping rates of twisted DA and DIA waves are analyzed with finite orbital angular momentum states in a multi-component dusty plasma. Significant modifications concerning the realmore » wave frequencies and damping rates appeared with varying twisted dimensionless parameter and dust concentration. In particular, it is shown that dust concentration enhances the phase speed of the DIA waves in contrary to DA waves, whereas the impact of twisted parameter reduces the frequencies of both DA and DIA waves. The results should be useful for the understanding of particle transport and trapping phenomena caused by wave excitation in laboratory dusty plasmas.« less

Transmission properties of C60 ions through micro- and nano-capillaries

NASA Astrophysics Data System (ADS)

Tsuchida, Hidetsugu; Majima, Takuya; Tomita, Shigeo; Sasa, Kimikazu; Narumi, Kazumasa; Saitoh, Yuichi; Chiba, Atsuya; Yamada, Keisuke; Hirata, Koichi; Shibata, Hiromi; Itoh, Akio

2013-11-01

We apply the capillary beam-focusing method for the C60 fullerene projectiles in the velocity range between 0.14 and 0.2 a.u. We study the C60 transmission properties through two different types of capillaries: (1) borosilicate glass microcapillary with an outlet diameter of 5.5 μm, and (2) Al2O3 multi-capillary foil with a pore size of about 70 nm and a high aspect ratio of about 750. We measured the transmitted particle composition by using the electrostatic deflection method combined with the microchannel plate imaging technique. For the experiments with the single microcapillary, the main transmission component is found to be primary C60 beams that are focused in the area equal to the capillary outlet diameter. Minor components are charge-exchanged C60 ions and charged or neutral fragments (fullerene-like C60-2m and small Cn particles), and their fractions decrease with decreasing the projectile velocity. It is concluded that the C60 transmission fraction is considerably high for both types of the capillaries in the present velocity range.

Size segregation of component coals during pulverization of high volatile/low volatile blends

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, A.; Orban, P.C.

1995-12-31

Samples of single high volatile (hvb) and low volatile (lvb) coals and binary blends in proportions ranging from 75%hvb/25%lvb to 25%hvb/75%lvb were pulverized in a Raymond 271 bowl mill and then screened into different size fractions. The ranks of two of the feed coals were sufficiently different that individual particles could be distinguished microscopically. This enabled the proportions of each feed coal in the various blend size fractions to be determined. The difference in rank and therefore grindability of the components (Hardgrove indices of 99 versus 50) was such that significant segregation resulted. For example, the 25%hvb/75%lvb blend, upon grinding,more » produced a +50 mesh (300 {micro}m) fraction with 30% lvb coal, and a {minus}325 mesh (45 {micro}m) fraction with 84% lvb coal. The effect of this segregation according to size was a notable progressive decrease in volatility towards the finer fractions, consistent with an increase in the proportion of lvb particles; differences in volatile matter (d.b.) between coarsest and finest fractions of up to 6.9% were encountered. Although most of the segregation is attributable to rank difference between the component coals, part appears to be due to the lower grindability of liptinite-rich lithotypes in the hvb coal.« less

Preliminary design of a prototype particulate stack sampler. [For stack gas temperature under 300/sup 0/C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elder, J.C.; Littlefield, L.G.; Tillery, M.I.

1978-06-01

A preliminary design of a prototype particulate stack sampler (PPSS) has been prepared, and development of several components is under way. The objective of this Environmental Protection Agency (EPA)-sponsored program is to develop and demonstrate a prototype sampler with capabilities similar to EPA Method 5 apparatus but without some of the more troublesome aspects. Features of the new design include higher sampling flow; display (on demand) of all variables and periodic calculation of percent isokinetic, sample volume, and stack velocity; automatic control of probe and filter heaters; stainless steel surfaces in contact with the sample stream; single-point particle size separationmore » in the probe nozzle; null-probe capability in the nozzle; and lower weight in the components of the sampling train. Design considerations will limit use of the PPSS to stack gas temperatures under approximately 300/sup 0/C, which will exclude sampling some high-temperature stacks such as incinerators. Although need for filter weighing has not been eliminated in the new design, introduction of a variable-slit virtual impactor nozzle may eliminate the need for mass analysis of particles washed from the probe. Component development has shown some promise for continuous humidity measurement by an in-line wet-bulb, dry-bulb psychrometer.« less

Comparison of three-dimensional particle tracking and sizing using plenoptic imaging and digital in-line holography

DOE PAGES

Hall, Elise M.; Thurow, Brian S.; Guildenbecher, Daniel R.

2016-08-08

Digital in-line holography (DIH) and plenoptic photography are two techniques for single-shot, volumetric measurement of 3D particle fields. Here we present a comparison of the two methods by applying plenoptic imaging to experimental configurations that have been previously investigated with DIH. These experiments include the tracking of secondary droplets from the impact of a water drop on a thin film of water and tracking of pellets from a shotgun. Both plenoptic imaging and DIH successfully quantify the 3D nature of these particle fields. Furthermore, this includes measurement of the 3D particle position, individual particle sizes, and three-component velocity vectors. Formore » the initial processing methods presented here, both techniques give out-of-plane positional accuracy of approximately 1–2 particle diameters. For a fixed image sensor, digital holography achieves higher effective in-plane spatial resolutions. However, collimated and coherent illumination makes holography susceptible to image distortion through index of refraction gradients, as demonstrated in the shotgun experiments. In contrast, plenoptic imaging allows for a simpler experimental configuration and, due to the use of diffuse, white-light illumination, plenoptic imaging is less susceptible to image distortion in the shotgun experiments.« less

Separation of harmful impurities from refuse derived fuels (RDF) by a fluidized bed.

PubMed

Krüger, B; Mrotzek, A; Wirtz, S

2014-02-01

In firing systems of cement production plants and coal-fired power plants, regular fossil fuels are increasingly substituted by alternative fuels. Rising energy prices and ambitious CO2-reduction goals promote the use of alternative fuels as a significant contribution to efficient energy recovery. One possibility to protect energy resources are refuse-derived fuels (RDF), which are produced during the treatment of municipal solid, commercial and industrial waste. The waste fractions suitable for RDF have a high calorific value and are often not suitable for material recycling. With current treatment processes, RDF still contains components which impede the utilization in firing systems or limit the degree of substitution. The content of these undesired components may amount to 4 wt%. These, in most cases incombustible particles which consist of mineral, ceramic and metallic materials can cause damages in the conveying systems (e. g. rotary feeder) or result in contaminations of the products (e. g. cement, chalk). Up-to-date separation processes (sieve machine, magnet separator or air classifier) have individual weaknesses that could hamper a secure separation of these particles. This article describes a new technology for the separation of impurities from refuse derived fuels based on a rotating fluidized bed. In this concept a rotating motion of the particle bed is obtained by the tangential injection of the fluidization gas in a static geometry. The RDF-particles experience a centrifugal force which fluidized the bed radially. The technical principle allows tearing up of particle clusters to single particles. Radially inwards the vertical velocity is much lower thus particles of every description can fall down there. For the subsequent separation of the particles by form and density an additionally cone shaped plate was installed in the centre. Impurities have a higher density and a compact form compared to combustible particles and can be separated with a high efficiency. The new technology was experimentally investigated and proven using model-RDF, actual-RDF and impurities of different densities. In addition, numerical simulations were also done. The fluidization chamber was operated in batch mode. The article describes experiences and difficulties in using rotating fluidized bed systems. Copyright © 2013 Elsevier Ltd. All rights reserved.

From cluster structures to nuclear molecules: The role of nodal structure of the single-particle wave functions

NASA Astrophysics Data System (ADS)

Afanasjev, A. V.; Abusara, H.

2018-02-01

The nodal structure of the density distributions of the single-particle states occupied in rod-shaped, hyper- and megadeformed structures of nonrotating and rotating N ˜Z nuclei has been investigated in detail. The single-particle states with the Nilsson quantum numbers of the [N N 0 ]1 /2 (with N from 0 to 5) and [N ,N -1 ,1 ]Ω (with N from 1 to 3 and Ω =1 /2 , 3/2) types are considered. These states are building blocks of extremely deformed shapes in the nuclei with mass numbers A ≤50 . Because of (near) axial symmetry and large elongation of such structures, the wave functions of the single-particle states occupied are dominated by a single basis state in cylindrical basis. This basis state defines the nodal structure of the single-particle density distribution. The nodal structure of the single-particle density distributions allows us to understand in a relatively simple way the necessary conditions for α clusterization and the suppression of the α clusterization with the increase of mass number. It also explains in a natural way the coexistence of ellipsoidal mean-field-type structures and nuclear molecules at similar excitation energies and the features of particle-hole excitations connecting these two types of the structures. Our analysis of the nodal structure of the single-particle density distributions does not support the existence of quantum liquid phase for the deformations and nuclei under study.

High sensitivity fluorescent single particle and single molecule detection apparatus and method

DOEpatents

Mathies, Richard A.; Peck, Konan; Stryer, Lubert

1990-01-01

Apparatus is described for ultrasensitive detection of single fluorescent particles down to the single fluorescent molecule limit in a fluid or on a substrate comprising means for illuminating a predetermined volume of the fluid or area of the substrate whereby to emit light including background light from the fluid and burst of photons from particles residing in the area. The photon burst is detected in real time to generate output representative signal. The signal is received and the burst of energy from the fluorescent particles is distinguished from the background energy to provide an indication of the number, location or concentration of the particles or molecules.

A quantitative estimation of the exhaust, abrasion and resuspension components of particulate traffic emissions using electron microscopy

NASA Astrophysics Data System (ADS)

Weinbruch, Stephan; Worringen, Annette; Ebert, Martin; Scheuvens, Dirk; Kandler, Konrad; Pfeffer, Ulrich; Bruckmann, Peter

2014-12-01

The contribution of the three traffic-related components exhaust, abrasion, and resuspension to kerbside and urban background PM10 and PM1 levels was quantified based on the analysis of individual particles by scanning electron microscopy. A total of 160 samples was collected on 38 days between February and September 2009 at a kerbside and an urban background station in the urban/industrial Ruhr area (Germany). Based on size, morphology, chemical composition and stability under electron bombardment, the 111,003 particles studied in detail were classified into the following 14 particle classes: traffic/exhaust, traffic/abrasion, traffic/resuspension, carbonaceous/organic, industry/metallurgy, industry/power plants, secondary particles, (aged) sea salt, silicates, Ca sulfates, carbonates, Fe oxides/hydroxides, biological particles, and other particles. The traffic/exhaust component consists predominantly of externally mixed soot particles and soot internally mixed with secondary particles. The traffic/abrasion component contains all particles with characteristic tracer elements (Fe, Cu, Ba, Sb, Zn) for brake and tire abrasion. The traffic/resuspension component is defined by the mixing state and comprises all internally mixed particles with a high proportion of silicates or Fe oxides/hydroxides which contain soot or abrasion particles as minor constituent. In addition, silicates and Fe oxides/hydroxides internally mixed with chlorine and sulphur containing particles were also assigned to the traffic/resuspension component. The total contribution of traffic to PM10 was found to be 27% at the urban background station and 48% at the kerbside station, the corresponding values for PM1 are 15% and 39%. These values lie within the range reported in previous literature. The relative share of the different traffic components for PM10 at the kerbside station was 27% exhaust, 15% abrasion, and 58% resuspension (38%, 8%, 54% for PM1). For the urban background, the following relative shares were obtained for PM10: 22% exhaust, 22% abrasion and 56% resuspension (40%, 27%, 33% for PM1). Compared to previous publications we have observed a significantly lower portion of exhaust particles and a significantly higher portion of resuspension particles. The high abundance of resuspension particles underlines their significance for the observed adverse health effects of traffic emissions and for mitigation measures.

Encapsidated Host Factors in Alphavirus Particles Influence Midgut Infection of Aedes aegypti.

PubMed

Mackenzie-Liu, David; Sokoloski, Kevin J; Purdy, Sarah; Hardy, Richard W

2018-05-16

Transmission of mosquito-borne viruses requires the efficient infection of both a permissive vertebrate host and a competent mosquito vector. The infectivity of Sindbis virus (SINV), the type species of the Alphavirus genus, is influenced by both the original and new host cell. We have shown that infection of vertebrate cells by SINV, chikungunya virus (CHIKV), and Ross River virus (RRV) produces two subpopulations of virus particles separable based on density. In contrast, a single population of viral particles is produced by mosquito cells. Previous studies demonstrated that the denser vertebrate-derived particles and the mosquito-derived particles contain components of the small subunit of the host cell ribosome, whereas the less dense vertebrate-derived particles do not. Infection of mice with RRV showed that both particle subpopulations are produced in an infected vertebrate, but in a tissue specific manner with serum containing only the less dense version of the virus particles. Previous infectivity studies using SINV particles have shown that the denser particles (SINV Heavy ) and mosquito derived particles SINV C6/36 are significantly more infectious in vertebrate cells than the less dense vertebrate derived particles (SINV Light ). The current study shows that SINV Light particles, initiate the infection of the mosquito midgut more efficiently than SINV Heavy particles and that this enhanced infectivity is associated with an exacerbated immune response to SINV Light infection in midgut tissues. The enhanced infection of SINV Light is specific to the midgut as intrathoracically injected virus do not exhibit the same fitness advantage. Together, our data indicate a biologically significant role for the SINV Light subpopulation in the efficient transmission from infected vertebrates to the mosquito vector.

Evolution of single-particle structure and beta-decay near 78Ni

NASA Astrophysics Data System (ADS)

Borzov, I. N.

2012-12-01

The extended self-consistent beta-decay model has been applied for bet-decay rates and delayed neutron emission probabilities of spherical neutron-rich isotopes near the r-process paths. Unlike a popular global FRDM+RPA model, in our fully microscopic approach, the Gamow-Teller and first-forbidden decays are treated on the same footing. The model has been augmented by blocking of the odd particle in order to account for important ground-state spin-parity inversion effect which has been shown to exist in the region of the most neutron-rich doubly-magic nucleus 78Ni. Finally, a newly developed form of density functional DF3a has been employed which gives a better spin-orbit splitting due to the modified tensor components of the density functional.

Single particles measured by a light scattering module coupled to a time-of-flight aerosol mass spectrometer onboard the NOAA P-3 aircraft during SENEX

NASA Astrophysics Data System (ADS)

Liao, J.; Middlebrook, A. M.; Welti, A.; Sueper, D.; Murphy, D. M.

2014-12-01

Single particles in the eastern US were characterized by a light scattering module coupled to a time-of-flight aerosol mass spectrometer (LS-ToF-AMS) onboard the NOAA P-3 aircraft during the Southeastern Nexus (SENEX) campaign. Single particle data were collected for 30 seconds every 5 minutes. Aerosols larger than 200-300 nm in vacuum aerodynamic diameter can be optically detected by the 405 nm crystal laser and trigger the saving of single particle mass spectra. The measured single particles are internally-mixed as expected. The single particles were classified as prompt, delayed, and null based on the chemical ion signal arrival time difference between prediction from the light scattering signal and measurement by mass spectrometer and the presence or absence of a mass spectrum. On average the number fraction of particles detected as prompt, delayed, and null (no spectrum) is about 30%, 10%, and 60%. The number fraction of these three particle types varied with aerosol size, chemical composition and the investigation region and will be discussed in detail. For example, the number fraction of prompt particles was significantly higher for the flight to the Pennsylvania natural gas shale region on July 6, 2013, which is probably related to the chemical composition (more acidic) and phase of the ambient particles. These particle types and detection efficiency are related to the bouncing effect on the vaporizer and may provide insight into the non-unit AMS collection efficiency. Moreover, most of the particles larger than 800 nm in vacuum aerodynamic diameter sized with the traditional AMS PToF mode are delayed particles and their mass spectral signals appear to be affected by this process.

Threshold singularities in a Fermi gas with attractive potential in one dimension

DOE PAGES

Schlottmann, P.; Zvyagin, A. A.

2015-01-15

We consider the one-dimensional gas of fermions with spin S interacting via an attractive δ-function potential using the Bethe Ansatz solution. In zero magnetic field the atoms form bound states of N=2S + 1 fermions, i.e. generalized Cooper states with each atom having a different spin component. For low energy excitations the system is a Luttinger liquid and is properly described by a conformal field theory with conformal charge c=1. The linear dispersion of a Luttinger liquid is asymptotically exact in the low-energy limit where the band curvature terms in the dispersion are irrelevant. For higher energy excitations, however, themore » spectral function displays deviations in the neighborhood of the single-particle (hole) energy, which can be described by an effective X-ray edge type model. Using the Bethe Ansatz solution we obtain expressions for the critical exponents for the single-particle (hole) Green’s function. This model can be relevant in the context of ultracold atoms with effective total spin S confined to an elongated optical trap.« less

Solid-phase diffusion mechanism for GaAs nanowire growth.

PubMed

Persson, Ann I; Larsson, Magnus W; Stenström, Stig; Ohlsson, B Jonas; Samuelson, Lars; Wallenberg, L Reine

2004-10-01

Controllable production of nanometre-sized structures is an important field of research, and synthesis of one-dimensional objects, such as nanowires, is a rapidly expanding area with numerous applications, for example, in electronics, photonics, biology and medicine. Nanoscale electronic devices created inside nanowires, such as p-n junctions, were reported ten years ago. More recently, hetero-structure devices with clear quantum-mechanical behaviour have been reported, for example the double-barrier resonant tunnelling diode and the single-electron transistor. The generally accepted theory of semiconductor nanowire growth is the vapour-liquid-solid (VLS) growth mechanism, based on growth from a liquid metal seed particle. In this letter we suggest the existence of a growth regime quite different from VLS. We show that this new growth regime is based on a solid-phase diffusion mechanism of a single component through a gold seed particle, as shown by in situ heating experiments of GaAs nanowires in a transmission electron microscope, and supported by highly resolved chemical analysis and finite element calculations of the mass transport and composition profiles.

Comparison of CREME (cosmic-ray effects on microelectronics) model LET (linear energy transfer) spaceflight dosimetry data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Letaw, J.R.; Adams, J.H.

The galactic cosmic radiation (GCR) component of space radiation is the dominant cause of single-event phenomena in microelectronic circuits when Earth's magnetic shielding is low. Spaceflights outside the magnetosphere and in high inclination orbits are examples of such circumstances. In high-inclination orbits, low-energy (high LET) particles are transmitted through the field only at extreme latitudes, but can dominate the orbit-averaged dose. GCR is an important part of the radiation dose to astronauts under the same conditions. As a test of the CREME environmental model and particle transport codes used to estimate single event upsets, we have compiled existing measurements ofmore » HZE doses were compiled where GCR is expected to be important: Apollo 16 and 17, Skylab, Apollo Soyuz Test Project, and Kosmos 782. The LET spectra, due to direct ionization from GCR, for each of these missions has been estimated. The resulting comparisons with data validate the CREME model predictions of high-LET galactic cosmic-ray fluxes to within a factor of two. Some systematic differences between the model and data are identified.« less

Quantum cryptography using single-particle entanglement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Jae-Weon; Lee, Eok Kyun; Chung, Yong Wook

2003-07-01

A quantum cryptography scheme based on entanglement between a single-particle state and a vacuum state is proposed. The scheme utilizes linear optics devices to detect the superposition of the vacuum and single-particle states. Existence of an eavesdropper can be detected by using a variant of Bell's inequality.

Individual aerosol particles in ambient and updraft conditions below convective cloud bases in the Oman mountain region

NASA Astrophysics Data System (ADS)

Semeniuk, T. A.; Bruintjes, R. T.; Salazar, V.; Breed, D. W.; Jensen, T. L.; Buseck, P. R.

2014-03-01

An airborne study of cloud microphysics provided an opportunity to collect aerosol particles in ambient and updraft conditions of natural convection systems for transmission electron microscopy (TEM). Particles were collected simultaneously on lacey carbon and calcium-coated carbon (Ca-C) TEM grids, providing information on particle morphology and chemistry and a unique record of the particle's physical state on impact. In total, 22 particle categories were identified, including single, coated, aggregate, and droplet types. The fine fraction comprised up to 90% mixed cation sulfate (MCS) droplets, while the coarse fraction comprised up to 80% mineral-containing aggregates. Insoluble (dry), partially soluble (wet), and fully soluble particles (droplets) were recorded on Ca-C grids. Dry particles were typically silicate grains; wet particles were mineral aggregates with chloride, nitrate, or sulfate components; and droplets were mainly aqueous NaCl and MCS. Higher numbers of droplets were present in updrafts (80% relative humidity (RH)) compared with ambient conditions (60% RH), and almost all particles activated at cloud base (100% RH). Greatest changes in size and shape were observed in NaCl-containing aggregates (>0.3 µm diameter) along updraft trajectories. Their abundance was associated with high numbers of cloud condensation nuclei (CCN) and cloud droplets, as well as large droplet sizes in updrafts. Thus, compositional dependence was observed in activation behavior recorded for coarse and fine fractions. Soluble salts from local pollution and natural sources clearly affected aerosol-cloud interactions, enhancing the spectrum of particles forming CCN and by forming giant CCN from aggregates, thus, making cloud seeding with hygroscopic flares ineffective in this region.

Mass spectra features of biomass burning boiler and coal burning boiler emitted particles by single particle aerosol mass spectrometer.

PubMed

Xu, Jiao; Li, Mei; Shi, Guoliang; Wang, Haiting; Ma, Xian; Wu, Jianhui; Shi, Xurong; Feng, Yinchang

2017-11-15

In this study, single particle mass spectra signatures of both coal burning boiler and biomass burning boiler emitted particles were studied. Particle samples were suspended in clean Resuspension Chamber, and analyzed by ELPI and SPAMS simultaneously. The size distribution of BBB (biomass burning boiler sample) and CBB (coal burning boiler sample) are different, as BBB peaks at smaller size, and CBB peaks at larger size. Mass spectra signatures of two samples were studied by analyzing the average mass spectrum of each particle cluster extracted by ART-2a in different size ranges. In conclusion, BBB sample mostly consists of OC and EC containing particles, and a small fraction of K-rich particles in the size range of 0.2-0.5μm. In 0.5-1.0μm, BBB sample consists of EC, OC, K-rich and Al_Silicate containing particles; CBB sample consists of EC, ECOC containing particles, while Al_Silicate (including Al_Ca_Ti_Silicate, Al_Ti_Silicate, Al_Silicate) containing particles got higher fractions as size increase. The similarity of single particle mass spectrum signatures between two samples were studied by analyzing the dot product, results indicated that part of the single particle mass spectra of two samples in the same size range are similar, which bring challenge to the future source apportionment activity by using single particle aerosol mass spectrometer. Results of this study will provide physicochemical information of important sources which contribute to particle pollution, and will support source apportionment activities. Copyright © 2017. Published by Elsevier B.V.

Anisotropic elasticity of quasi-one-component polymer nanocomposites.

PubMed

Voudouris, Panayiotis; Choi, Jihoon; Gomopoulos, Nikos; Sainidou, Rebecca; Dong, Hongchen; Matyjaszewski, Krzysztof; Bockstaller, Michael R; Fytas, George

2011-07-26

The in-plane and out-of-plane elastic properties of thin films of "quasi-one-component" particle-brush-based nanocomposites are compared to those of "classical" binary particle-polymer nanocomposite systems with near identical overall composition using Brillouin light scattering. Whereas phonon propagation is found to be independent of the propagation direction for the binary particle/polymer blend systems, a pronounced splitting of the phonon propagation velocity along the in-plane and out-of-plane film direction is observed for particle-brush systems. The anisotropic elastic properties of quasi-one-component particle-brush systems are interpreted as a consequence of substrate-induced order formation into layer-type structures and the associated breaking of the symmetry of the film. The results highlight new opportunities to engineer quasi-one-component nanocomposites with advanced control of structural and physical property characteristics based on the assembly of particle-brush materials.

Pairing of one-dimensional Bose-Fermi mixtures with unequal masses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rizzi, Matteo; Max Planck Institut fuer QuantenOptik, Hans Kopfermann Strasse 1, D-85748 Garching; Imambekov, Adilet

We have considered one-dimensional Bose-Fermi mixture with equal densities and unequal masses using numerical density matrix renormalization group. For the mass ratio of K-Rb mixture and attraction between bosons and fermions, we determined the phase diagram. For weak boson-boson interactions, there is a direct transition between two-component Luttinger liquid and collapsed phases as the boson-fermion attraction is increased. For strong enough boson-boson interactions, we find an intermediate 'paired' phase, which is a single-component Luttinger liquid of composite particles. We investigated correlation functions of such a 'paired' phase, studied the stability of 'paired' phase to density imbalance, and discussed various experimentalmore » techniques which can be used to detect it.« less

LEGO: A modular accelerator design code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Y.; Donald, M.; Irwin, J.

1997-08-01

An object-oriented accelerator design code has been designed and implemented in a simple and modular fashion. It contains all major features of its predecessors: TRACY and DESPOT. All physics of single-particle dynamics is implemented based on the Hamiltonian in the local frame of the component. Components can be moved arbitrarily in the three dimensional space. Several symplectic integrators are used to approximate the integration of the Hamiltonian. A differential algebra class is introduced to extract a Taylor map up to arbitrary order. Analysis of optics is done in the same way both for the linear and nonlinear case. Currently, themore » code is used to design and simulate the lattices of the PEP-II. It will also be used for the commissioning.« less

The hrp23 Protein in the Balbiani Ring Pre-mRNP Particles Is Released Just before or at the Binding of the Particles to the Nuclear Pore Complex

PubMed Central

Sun, Xin; Alzhanova-Ericsson, Alla T.; Visa, Neus; Aissouni, Youssef; Zhao, Jian; Daneholt, Bertil

1998-01-01

Balbiani ring (BR) pre-mRNP particles reside in the nuclei of salivary glands of the dipteran Chironomus tentans and carry the message for giant-sized salivary proteins. In the present study, we identify and characterize a new protein component in the BR ribonucleoprotein (RNP) particles, designated hrp23. The protein with a molecular mass of 20 kD has a single RNA-binding domain and a glycine-arginine-serine–rich auxiliary domain. As shown by immunoelectron microscopy, the hrp23 protein is added to the BR transcript concomitant with transcription, is still present in the BR particles in the nucleoplasm, but is absent from the BR particles that are bound to the nuclear pore complex or are translocating through the central channel of the complex. Thus, hrp23 is released just before or at the binding of the particles to the nuclear pore complex. It is noted that hrp23 behaves differently from two other BR RNP proteins earlier studied: hrp36 and hrp45. These proteins both reach the nuclear pore complex, and hrp36 even accompanies the RNA into the cytoplasm. It is concluded that each BR RNA-binding protein seems to have a specific flow pattern, probably related to the particular role of the protein in gene expression. PMID:9732280

Wood combustion particles induce adverse effects to normal and diseased airway epithelia.

PubMed

Krapf, Manuel; Künzi, Lisa; Allenbach, Sandrine; Bruns, Emily A; Gavarini, Ilaria; El-Haddad, Imad; Slowik, Jay G; Prévôt, André S H; Drinovec, Luka; Močnik, Griša; Dümbgen, Lutz; Salathe, Matthias; Baumlin, Nathalie; Sioutas, Constantinos; Baltensperger, Urs; Dommen, Josef; Geiser, Marianne

2017-04-19

Residential wood burning is a major source of poorly characterized, deleterious particulate matter, whose composition and toxicity may vary with wood type, burning condition and photochemical age. The causative link between ambient wood particle constituents and observed adverse health effects is currently lacking. Here we investigate the relationship between chemical properties of primary and atmospherically aged wood combustion particles and acute toxicity in human airway epithelial cells. Emissions from a log wood burner were diluted and injected into a smog chamber for photochemical aging. After concentration-enrichment and removal of oxidizing gases, directly emitted and atmospherically aged particles were deposited on cell cultures at the air-liquid interface for 2 hours in an aerosol deposition chamber mimicking physiological conditions in lungs. Cell models were fully differentiated normal and diseased (cystic fibrosis and asthma) human bronchial epithelia (HBE) and the bronchial epithelial cell line BEAS-2B. Cell responses were assessed at 24 hours after aerosol exposure. Atmospherically relevant doses of wood combustion particles significantly increased cell death in all but the asthma cell model. Expression of oxidative stress markers increased in HBE from all donors. Increased cell death and inflammatory responses could not be assigned to a single chemical fraction of the particles. Exposure to primary and aged wood combustion particles caused adverse effects to airway epithelia, apparently induced by several interacting components.

Insights into Bacteriophage T5 Structure from Analysis of Its Morphogenesis Genes and Protein Components

PubMed Central

Zivanovic, Yvan; Confalonieri, Fabrice; Ponchon, Luc; Lurz, Rudi; Chami, Mohamed; Flayhan, Ali; Renouard, Madalena; Huet, Alexis; Decottignies, Paulette; Davidson, Alan R.; Breyton, Cécile

2014-01-01

Bacteriophage T5 represents a large family of lytic Siphoviridae infecting Gram-negative bacteria. The low-resolution structure of T5 showed the T=13 geometry of the capsid and the unusual trimeric organization of the tail tube, and the assembly pathway of the capsid was established. Although major structural proteins of T5 have been identified in these studies, most of the genes encoding the morphogenesis proteins remained to be identified. Here, we combine a proteomic analysis of T5 particles with a bioinformatic study and electron microscopic immunolocalization to assign function to the genes encoding the structural proteins, the packaging proteins, and other nonstructural components required for T5 assembly. A head maturation protease that likely accounts for the cleavage of the different capsid proteins is identified. Two other proteins involved in capsid maturation add originality to the T5 capsid assembly mechanism: the single head-to-tail joining protein, which closes the T5 capsid after DNA packaging, and the nicking endonuclease responsible for the single-strand interruptions in the T5 genome. We localize most of the tail proteins that were hitherto uncharacterized and provide a detailed description of the tail tip composition. Our findings highlight novel variations of viral assembly strategies and of virion particle architecture. They further recommend T5 for exploring phage structure and assembly and for deciphering conformational rearrangements that accompany DNA transfer from the capsid to the host cytoplasm. PMID:24198424

Single-molecule detection of proteins with antigen-antibody interaction using resistive-pulse sensing of submicron latex particles

NASA Astrophysics Data System (ADS)

Takakura, T.; Yanagi, I.; Goto, Y.; Ishige, Y.; Kohara, Y.

2016-03-01

We developed a resistive-pulse sensor with a solid-state pore and measured the latex agglutination of submicron particles induced by antigen-antibody interaction for single-molecule detection of proteins. We fabricated the pore based on numerical simulation to clearly distinguish between monomer and dimer latex particles. By measuring single dimers agglutinated in the single-molecule regime, we detected single human alpha-fetoprotein molecules. Adjusting the initial particle concentration improves the limit of detection (LOD) to 95 fmol/l. We established a theoretical model of the LOD by combining the reaction kinetics and the counting statistics to explain the effect of initial particle concentration on the LOD. The theoretical model shows how to improve the LOD quantitatively. The single-molecule detection studied here indicates the feasibility of implementing a highly sensitive immunoassay by a simple measurement method using resistive-pulse sensing.

Single exposure three-dimensional imaging of dusty plasma clusters.

PubMed

Hartmann, Peter; Donkó, István; Donkó, Zoltán

2013-02-01

We have worked out the details of a single camera, single exposure method to perform three-dimensional imaging of a finite particle cluster. The procedure is based on the plenoptic imaging principle and utilizes a commercial Lytro light field still camera. We demonstrate the capabilities of our technique on a single layer particle cluster in a dusty plasma, where the camera is aligned and inclined at a small angle to the particle layer. The reconstruction of the third coordinate (depth) is found to be accurate and even shadowing particles can be identified.

Clearing the waters: Evaluating the need for site-specific field fluorescence corrections based on turbidity measurements

USGS Publications Warehouse

Saraceno, John F.; Shanley, James B.; Downing, Bryan D.; Pellerin, Brian A.

2017-01-01

In situ fluorescent dissolved organic matter (fDOM) measurements have gained increasing popularity as a proxy for dissolved organic carbon (DOC) concentrations in streams. One challenge to accurate fDOM measurements in many streams is light attenuation due to suspended particles. Downing et al. (2012) evaluated the need for corrections to compensate for particle interference on fDOM measurements using a single sediment standard in a laboratory study. The application of those results to a large river improved unfiltered field fDOM accuracy. We tested the same correction equation in a headwater tropical stream and found that it overcompensated fDOM when turbidity exceeded ∼300 formazin nephelometric units (FNU). Therefore, we developed a site-specific, field-based fDOM correction equation through paired in situ fDOM measurements of filtered and unfiltered streamwater. The site-specific correction increased fDOM accuracy up to a turbidity as high as 700 FNU, the maximum observed in this study. The difference in performance between the laboratory-based correction equation of Downing et al. (2012) and our site-specific, field-based correction equation likely arises from differences in particle size distribution between the sediment standard used in the lab (silt) and that observed in our study (fine to medium sand), particularly during high flows. Therefore, a particle interference correction equation based on a single sediment type may not be ideal when field sediment size is significantly different. Given that field fDOM corrections for particle interference under turbid conditions are a critical component in generating accurate DOC estimates, we describe a way to develop site-specific corrections.

Computational modeling of magnetic particle margination within blood flow through LAMMPS

NASA Astrophysics Data System (ADS)

Ye, Huilin; Shen, Zhiqiang; Li, Ying

2017-11-01

We develop a multiscale and multiphysics computational method to investigate the transport of magnetic particles as drug carriers in blood flow under influence of hydrodynamic interaction and external magnetic field. A hybrid coupling method is proposed to handle red blood cell (RBC)-fluid interface (CFI) and magnetic particle-fluid interface (PFI), respectively. Immersed boundary method (IBM)-based velocity coupling is used to account for CFI, which is validated by tank-treading and tumbling behaviors of a single RBC in simple shear flow. While PFI is captured by IBM-based force coupling, which is verified through movement of a single magnetic particle under non-uniform external magnetic field and breakup of a magnetic chain in rotating magnetic field. These two components are seamlessly integrated within the LAMMPS framework, which is a highly parallelized molecular dynamics solver. In addition, we also implement a parallelized lattice Boltzmann simulator within LAMMPS to handle the fluid flow simulation. Based on the proposed method, we explore the margination behaviors of magnetic particles and magnetic chains within blood flow. We find that the external magnetic field can be used to guide the motion of these magnetic materials and promote their margination to the vascular wall region. Moreover, the scaling performance and speedup test further confirm the high efficiency and robustness of proposed computational method. Therefore, it provides an efficient way to simulate the transport of nanoparticle-based drug carriers within blood flow in a large scale. The simulation results can be applied in the design of efficient drug delivery vehicles that optimally accumulate within diseased tissue, thus providing better imaging sensitivity, therapeutic efficacy and lower toxicity.

Multi-party quantum summation without a trusted third party based on single particles

NASA Astrophysics Data System (ADS)

Zhang, Cai; Situ, Haozhen; Huang, Qiong; Yang, Pingle

We propose multi-party quantum summation protocols based on single particles, in which participants are allowed to compute the summation of their inputs without the help of a trusted third party and preserve the privacy of their inputs. Only one participant who generates the source particles needs to perform unitary operations and only single particles are needed in the beginning of the protocols.

A Critical Appraisal of the "Day" Diagram

NASA Astrophysics Data System (ADS)

Roberts, Andrew P.; Tauxe, Lisa; Heslop, David; Zhao, Xiang; Jiang, Zhaoxia

2018-04-01

The "Day" diagram (Day et al., 1977, https://doi.org/10.1016/0031-9201(77)90108-X) is used widely to make inferences about the domain state of magnetic mineral assemblages. Based on theoretical and empirical arguments, the Day diagram is demarcated into stable "single domain" (SD), "pseudo single domain" ("PSD"), and "multidomain" (MD) zones. It is straightforward to make the necessary measurements for a sample and to plot results within the "domain state" framework based on the boundaries defined by Day et al. (1977, https://doi.org/10.1016/0031-9201(77)90108-X). We discuss 10 issues that limit Day diagram interpretation, including (1) magnetic mineralogy, (2) the associated magnetocrystalline anisotropy type, (3) mineral stoichiometry, (4) stress state, (5) surface oxidation, (6) magnetostatic interactions, (7) particle shape, (8) thermal relaxation, (9) magnetic particle mixtures, and (10) definitional/measurement issues. In most studies, these variables are unknowns and cannot be controlled for, so that hysteresis parameters for single bulk samples are nonunique and any data point in a Day diagram could result from infinite combinations of relevant variables. From this critical appraisal, we argue that the Day diagram is fundamentally ambiguous for domain state diagnosis. Widespread use of the Day diagram has also contributed significantly to prevalent but questionable views, including underrecognition of the importance of stable SD particles in the geological record and reinforcement of the unhelpful PSD concept and of its geological importance. Adoption of approaches that enable correct domain state diagnosis should be an urgent priority for component-specific understanding of magnetic mineral assemblages and for quantitative rock magnetic interpretation.

Sheathless Size-Based Acoustic Particle Separation

PubMed Central

Guldiken, Rasim; Jo, Myeong Chan; Gallant, Nathan D.; Demirci, Utkan; Zhe, Jiang

2012-01-01

Particle separation is of great interest in many biological and biomedical applications. Flow-based methods have been used to sort particles and cells. However, the main challenge with flow based particle separation systems is the need for a sheath flow for successful operation. Existence of the sheath liquid dilutes the analyte, necessitates precise flow control between sample and sheath flow, requires a complicated design to create sheath flow and separation efficiency depends on the sheath liquid composition. In this paper, we present a microfluidic platform for sheathless particle separation using standing surface acoustic waves. In this platform, particles are first lined up at the center of the channel without introducing any external sheath flow. The particles are then entered into the second stage where particles are driven towards the off-center pressure nodes for size based separation. The larger particles are exposed to more lateral displacement in the channel due to the acoustic force differences. Consequently, different-size particles are separated into multiple collection outlets. The prominent feature of the present microfluidic platform is that the device does not require the use of the sheath flow for positioning and aligning of particles. Instead, the sheathless flow focusing and separation are integrated within a single microfluidic device and accomplished simultaneously. In this paper, we demonstrated two different particle size-resolution separations; (1) 3 μm and 10 μm and (2) 3 μm and 5 μm. Also, the effects of the input power, the flow rate, and particle concentration on the separation efficiency were investigated. These technologies have potential to impact broadly various areas including the essential microfluidic components for lab-on-a-chip system and integrated biological and biomedical applications. PMID:22368502

A Wide Field of View Plasma Spectrometer

DOE PAGES

Skoug, Ruth M.; Funsten, Herbert O.; Moebius, Eberhard; ...

2016-07-01

Here we present a fundamentally new type of space plasma spectrometer, the wide field of view plasma spectrometer, whose field of view is >1.25π ster using fewer resources than traditional methods. The enabling component is analogous to a pinhole camera with an electrostatic energy-angle filter at the image plane. Particle energy-per-charge is selected with a tunable bias voltage applied to the filter plate relative to the pinhole aperture plate. For a given bias voltage, charged particles from different directions are focused by different angles to different locations. Particles with appropriate locations and angles can transit the filter plate and aremore » measured using a microchannel plate detector with a position-sensitive anode. Full energy and angle coverage are obtained using a single high-voltage power supply, resulting in considerable resource savings and allowing measurements at fast timescales. Lastly, we present laboratory prototype measurements and simulations demonstrating the instrument concept and discuss optimizations of the instrument design for application to space measurements.« less

Single particle chemical composition, state of mixing and shape of fresh and aged Saharan dust in Morocco and at Cape Verde Islands during SAMUM I and II

NASA Astrophysics Data System (ADS)

Kandler, Konrad; Emmel, Carmen; Ebert, Martin; Lieke, Kirsten; Müller-Ebert, Dörthe; Schütz, Lothar; Weinbruch, Stephan

2010-05-01

The Saharan Mineral Dust Experiment (SAMUM) is focussed to the understanding of the radiative effects of mineral dust. During the SAMUM 2006 field campaign at Tinfou, southern Morocco, chemical and mineralogical properties of fresh desert aerosol was measured. The winter campaign of Saharan Mineral Dust Experiment II in 2008 was based in Praia, Island of Santiago, Cape Verde. This second field campaign was dedicated to the investigation of transported Saharan Mineral Dust. Ground-based and airborne measurements were performed in the winter season, where mineral dust from the Western Sahara and biomass burning aerosol from the Sahel region occurred. Samples were collected with a miniature impactor system, a sedimentation trap, a free-wing impactor, and a filter sampler. Beryllium discs as well as carbon coated nickel discs, carbon foils, and nuclepore and fiber filters were used as sampling substrates. The size-resolved particle aspect ratio and the chemical composition are determined by scanning electron microscopy and energy-dispersive X-ray microanalysis of single particles. Mineralogical bulk composition is determined by X-ray diffraction analysis. In Morocco, three size regimes are identified in the aerosol: Smaller than 500 nm in diameter, the aerosol consists of sulfates and mineral dust. Larger than 500 nm up to 50 µm, mineral dust dominates, consisting mainly of silicates, and - to a lesser extent - carbonates and quartz. Larger than 50 µm, approximately half of the particles consist of quartz. Time series of the elemental composition show a moderate temporal variability of the major compounds. Calcium-dominated particles are enhanced during advection from a prominent dust source in Northern Africa (Chott El Djerid and surroundings). More detailed results are found in Kandler et al. (2009) At Praia, Cape Verde, the boundary layer aerosol consists of a superposition of mineral dust, marine aerosol and ammonium sulfate, soot, and other sulfates as well as mixtures of these components. During low-dust periods, the aerosol is dominated by sea salt. During dust events, mineral dust dominates the particle mass (more than 90 %). Particles smaller 500 nm in diameter always show a significant abundance of ammonium sulfate. Comparing a high dust period at Cape Verde with the total data from Morocco, it is found that the atomic ratio distributions of Al/Si, K/Si and Fe/Si for the single particles are very similar for the dust component. This indicates that the dominating silicate minerals are the same. In contrast, the content of calcium rich minerals at Cape Verde is significantly lower than in Morocco which is in agreement with the source regions for the Cape Verde dust (E Mali and W Niger) derived from trajectory analysis. The sulfur content of super-micron aerosol particles at Cape Verde scales with the particle surface, indicating the presence of sulfate coatings. For the submicron particles, the sulfur content scales with particle volume, which can be attributed to the large amount of particles identified as ammonium sulfate. In contrast to findings in Japan (Zhang et al., 2006), no internal mixtures between pristine seasalt and mineral dust are present during this dust period at Cape Verde. However, for a significant number of particles a small amount of sodium and chlorine is associated with internal mixtures of dust and sulfate, what may indicate that these particles started as internal mixture of dust with a sea water droplet before taking up more sulfur from the gas phase. In general, the shape of the particles in Morocco and Cape Verde is rather similar: The distributions of the two-dimensional aspect ratio of an ellipse fitted to each particle's shape for the total aerosol show no significant differences. A median value of 1.6 is found for both locations. References Kandler, K., Schütz, L., Deutscher, C., Hofmann, H., Jäckel, S. and co-authors 2009. Tellus 61B, 32-50. Zhang, D., Iwasaka, Y., Matsuki, A., Ueno, K. and Matsuzaki, T. 2006. Atmos. Environ. 40, 1205-1215. Financial support by the Deutsche Forschungsgemeinschaft (research group SAMUM, FOR539) is gratefully acknowledged. We thank TACV - Cabo Verde Airlines and Mr. António Lima Fortes for logistic support.

A deep convolutional neural network approach to single-particle recognition in cryo-electron microscopy.

PubMed

Zhu, Yanan; Ouyang, Qi; Mao, Youdong

2017-07-21

Single-particle cryo-electron microscopy (cryo-EM) has become a mainstream tool for the structural determination of biological macromolecular complexes. However, high-resolution cryo-EM reconstruction often requires hundreds of thousands of single-particle images. Particle extraction from experimental micrographs thus can be laborious and presents a major practical bottleneck in cryo-EM structural determination. Existing computational methods for particle picking often use low-resolution templates for particle matching, making them susceptible to reference-dependent bias. It is critical to develop a highly efficient template-free method for the automatic recognition of particle images from cryo-EM micrographs. We developed a deep learning-based algorithmic framework, DeepEM, for single-particle recognition from noisy cryo-EM micrographs, enabling automated particle picking, selection and verification in an integrated fashion. The kernel of DeepEM is built upon a convolutional neural network (CNN) composed of eight layers, which can be recursively trained to be highly "knowledgeable". Our approach exhibits an improved performance and accuracy when tested on the standard KLH dataset. Application of DeepEM to several challenging experimental cryo-EM datasets demonstrated its ability to avoid the selection of un-wanted particles and non-particles even when true particles contain fewer features. The DeepEM methodology, derived from a deep CNN, allows automated particle extraction from raw cryo-EM micrographs in the absence of a template. It demonstrates an improved performance, objectivity and accuracy. Application of this novel method is expected to free the labor involved in single-particle verification, significantly improving the efficiency of cryo-EM data processing.

Single-particle dispersion in compressible turbulence

NASA Astrophysics Data System (ADS)

Zhang, Qingqing; Xiao, Zuoli

2018-04-01

Single-particle dispersion statistics in compressible box turbulence are studied using direct numerical simulation. Focus is placed on the detailed discussion of effects of the particle Stokes number and turbulent Mach number, as well as the forcing type. When solenoidal forcing is adopted, it is found that the single-particle dispersion undergoes a transition from the ballistic regime at short times to the diffusive regime at long times, in agreement with Taylor's particle dispersion argument. The strongest dispersion of heavy particles is announced when the Stokes number is of order 1, which is similar to the scenario in incompressible turbulence. The dispersion tends to be suppressed as the Mach number increases. When hybrid solenoidal and compressive forcing at a ratio of 1/2 is employed, the flow field shows apparent anisotropic property, characterized by the appearance of large shock wave structures. Accordingly, the single-particle dispersion shows extremely different behavior from the solenoidal forcing case.

Single α-particle irradiation permits real-time visualization of RNF8 accumulation at DNA damaged sites

NASA Astrophysics Data System (ADS)

Muggiolu, Giovanna; Pomorski, Michal; Claverie, Gérard; Berthet, Guillaume; Mer-Calfati, Christine; Saada, Samuel; Devès, Guillaume; Simon, Marina; Seznec, Hervé; Barberet, Philippe

2017-01-01

As well as being a significant source of environmental radiation exposure, α-particles are increasingly considered for use in targeted radiation therapy. A better understanding of α-particle induced damage at the DNA scale can be achieved by following their tracks in real-time in targeted living cells. Focused α-particle microbeams can facilitate this but, due to their low energy (up to a few MeV) and limited range, α-particles detection, delivery, and follow-up observations of radiation-induced damage remain difficult. In this study, we developed a thin Boron-doped Nano-Crystalline Diamond membrane that allows reliable single α-particles detection and single cell irradiation with negligible beam scattering. The radiation-induced responses of single 3 MeV α-particles delivered with focused microbeam are visualized in situ over thirty minutes after irradiation by the accumulation of the GFP-tagged RNF8 protein at DNA damaged sites.

Tripartite assembly of RND multidrug efflux pumps

NASA Astrophysics Data System (ADS)

Daury, Laetitia; Orange, François; Taveau, Jean-Christophe; Verchère, Alice; Monlezun, Laura; Gounou, Céline; Marreddy, Ravi K. R.; Picard, Martin; Broutin, Isabelle; Pos, Klaas M.; Lambert, Olivier

2016-02-01

Tripartite multidrug efflux systems of Gram-negative bacteria are composed of an inner membrane transporter, an outer membrane channel and a periplasmic adaptor protein. They are assumed to form ducts inside the periplasm facilitating drug exit across the outer membrane. Here we present the reconstitution of native Pseudomonas aeruginosa MexAB-OprM and Escherichia coli AcrAB-TolC tripartite Resistance Nodulation and cell Division (RND) efflux systems in a lipid nanodisc system. Single-particle analysis by electron microscopy reveals the inner and outer membrane protein components linked together via the periplasmic adaptor protein. This intrinsic ability of the native components to self-assemble also leads to the formation of a stable interspecies AcrA-MexB-TolC complex suggesting a common mechanism of tripartite assembly. Projection structures of all three complexes emphasize the role of the periplasmic adaptor protein as part of the exit duct with no physical interaction between the inner and outer membrane components.

Heavy ions in space (M0001)

NASA Technical Reports Server (NTRS)

Adams, J. H., Jr.; Slberberg, R.; Tsao, C. H.

1984-01-01

The ojectives are to investigate three components of heavy nuclei in space: (1) a recently observed anomalous component of low-energy nuclei of N, O, and Ne; (2) the heavy nuclei in the Van Allen radiation belts; and (3) the UH nuclei (Z 30) of the galactic radiation. The study of the anomalous flux of N, O, and Ne nuclei in the unexplored energy region above 100 MeV/u is expected to provide new insights into the source of this component. Its observation in this experiment will confirm that these ions are singly charged. Knowledge of the energy spectra of the heavy nuclei observed in the Van Allen belts is expected to enhance the understanding of the origin of the belts (e.g., injection and local acceleration pocesses). The observation of these heavy ions could show, for the first time, that low-energy particles of extraterrestrial origin can diffuse to the innermost parts of the magnetosphere. Measurements of the UH component are expected to contribute information concerning its source, interstellar propagation, and the galactic storage time.

Responsive polymer-based colloids for drug delivery and bioconversion

NASA Astrophysics Data System (ADS)

Kudina, Olena

Responsive polymer-based colloids (RPBC) are the colloidal structures containing responsive polymeric component which is able to adapt its physico-chemical properties to the environment by undergoing chemical and/or conformational changes. The goal of the dissertation is to develop and characterize several groups of RPBC with different morphological complexity and explore their potential in drug delivery and bioconversion. The role of RPBC morphology for these specific applications is discussed in details. Three groups of RPBC were fabricated: i. polymeric micelles; ii. mixed polymeric micelles; iii. hybrid polymer-inorganic particles. All fabricated RPBCs contain polymeric component in their structure. The dissertation investigates how the changes of the responsive polymeric component properties are reflected in morphologies of RPBC. The first group of RPBC, polymeric micelles, was formed by the self-assembly of amphiphilic invertible polymers (AIPs) synthesized in our group. AIPs self-assemble into invertible micellar assemblies (IMAs) in solvents of different polarity. In this work, IMAs ability to invert the structure as a response to the change in solvent polarity was demonstrated using 1H NMR spectroscopy and SANS. It was shown that the IMAs incorporate hydrophobic cargo either in the core or in the shell, depending on the chemical structure of cargo molecules. Following in vitro study demonstrates that loaded with drug (curcumin) IMAs are cytotoxic to osteosarcoma cells. Mixed polymeric micelles represent another, more complex, RPBC morphologies studied in the dissertation. Mixed micelles were fabricated from AIPs and amphiphilic oligomers synthesized from pyromellitic dianhydride, polyethylene glycol methyl ethers, and alkanols/cholesterol. The combination of selected AIP and oligomers based on cholesterol results in mixed micelles with an increased drug-loading capacity (from 10% w/w loaded curcumin in single component IMAs to 26%w/w in mixed micelles). Even more complex colloids are hybrid polymer-inorganic particles, the third RPBC group studied in dissertation. Material was designed as core--shell particles with superparamagnetic core engulfed by grafted polymer brushes. These particles were loaded with enzymes (cellulases), thus, are turned into enzymogels for cellulose bioconversion. The study demonstrates that such RPBCs can be used multiple times during hydrolysis and provide an about four-fold increase in glucose production in comparison to free enzymes.

Combining external and internal mixing representation of atmospheric aerosol for optical properties calculations: focus on absorption properties over Europe and North America using AERONET observations and AQMEII simulations

NASA Astrophysics Data System (ADS)

Curci, Gabriele

2017-04-01

The calculation of optical properties from knowledge of the composition and abundance of atmospheric aerosol implies a certain number of assumptions. First and if not known or explicitly simulated, a size distribution must be assigned to each aerosol component (e.g. sulfate-like inorganic ions, organic and back carbon, soil dust, sea salt). Second, physical-chemical properties such as the shape, density, complex refractive index, and hygroscopic factors must be associated to each aerosol species. Third, a representation of how the aerosol species combine together must be made: among those, the most popular are the assumptions of external mixing, in which each particle is assumed to be formed of a single compound and the optical properties may be calculated separately for each species, or of internal core-shell arrangement, in which each particle consists of a water-insoluble core coated with a water-soluble shell and that requires more elaborate calculations for optical properties. Previous work found that the assumption on the mixing state (external or core-shell internal) is the one that introduces the highest uncertainty, quantified in about 30% uncertainty on the calculation of monthly mean aerosol optical depth (AOD) and single-scattering albedo (SSA). The external mixing assumption is generally more reasonable for freshly emitted aerosol, while the internal mixing case is associated with aged aerosol that had the time to form the coating around the core. Both approximations are thus regarded as valid, but in general a combination of the two mixing states may be expected in a given air mass. In this work, we test a simple empirical parameterization of the fraction of internally mixed particles (F_in) in a generic air mass. The F_in fraction is calculated in two alternative ways, one exploiting the NOz to NOx ratio (proxy of the photochemical aging), and the other using the relative abundance of black carbon with respect to other aerosol components (proxy of the coating formation). We compare sunphotometer observations from the AERosol RObotic NETwork (AERONET, http://aeronet.gsfc.nasa.gov/) across Europe and North America for the year 2010 with simulations from the Air Quality Modeling Evaluation International Initiative (AQMEII, http://aqmeii.jrc.ec.europa.eu/). The calculation of optical properties from simulated aerosol profiles is carried out using a single post-processing tool (FlexAOD, http://pumpkin.aquila.infn.it/flexaod/) that allows explicit and flexible assignment of the underlying assumptions mentioned above. We found that the combination of externally and internally mixed particles weighted through the F_in fraction gives the best agreement between models and observations, in particular regarding the single-scattering albedo.

Superluminal tunneling of a relativistic half-integer spin particle through a potential barrier

NASA Astrophysics Data System (ADS)

Nanni, Luca

2017-11-01

This paper investigates the problem of a relativistic Dirac half-integer spin free particle tunneling through a rectangular quantum-mechanical barrier. If the energy difference between the barrier and the particle is positive, and the barrier width is large enough, there is proof that the tunneling may be superluminal. For first spinor components of particle and antiparticle states, the tunneling is always superluminal regardless the barrier width. Conversely, the second spinor components of particle and antiparticle states may be either subluminal or superluminal depending on the barrier width. These results derive from studying the tunneling time in terms of phase time. For the first spinor components of particle and antiparticle states, it is always negative while for the second spinor components of particle and antiparticle states, it is always positive, whatever the height and width of the barrier. In total, the tunneling time always remains positive for particle states while it becomes negative for antiparticle ones. Furthermore, the phase time tends to zero, increasing the potential barrier both for particle and antiparticle states. This agrees with the interpretation of quantum tunneling that the Heisenberg uncertainty principle provides. This study's results are innovative with respect to those available in the literature. Moreover, they show that the superluminal behaviour of particles occurs in those processes with high-energy confinement.

Characterizing oxidative flow reactor SOA production and OH radical exposure from laboratory experiments of complex mixtures (engine exhaust) and simple precursors (monoterpenes)

NASA Astrophysics Data System (ADS)

Michael Link, M. L.; Friedman, B.; Ortega, J. V.; Son, J.; Kim, J.; Park, G.; Park, T.; Kim, K.; Lee, T.; Farmer, D.

2016-12-01

Recent commercialization of the Oxidative Flow Reactor (OFR, occasionally described in the literature as a "Potential Aerosol Mass") has created the opportunity for many researchers to explore the mechanisms behind OH-driven aerosol formation on a wide range of oxidative timescales (hours to weeks) in both laboratory and field measurements. These experiments have been conducted in both laboratory and field settings, including simple (i.e. single component) and complex (multi-component) precursors. Standard practices for performing OFR experiments, and interpreting data from the measurements, are still being developed. Measurement of gas and particle phase chemistry, from oxidation products generated in the OFR, through laboratory studies on single precursors and the measurement of SOA from vehicle emissions on short atmospheric timescales represent two very different experiments in which careful experimental design is essential for exploring reaction mechanisms and SOA yields. Two parameters essential in experimental design are (1) the role of seed aerosol in controlling gas-particle partitioning and SOA yields, and (2) the accurate determination of OH exposure during any one experiment. We investigated the role of seed aerosol surface area in controlling the observed SOA yields and gas/particle composition from the OH-initiated oxidation of four monoterpenes using an aerosol chemical ionization time-of-flight mass spectrometer and scanning mobility particle sizer. While the OH exposure during laboratory experiments is simple to constrain, complex mixtures such as diesel exhaust have high estimated OH reactivity values, and thus require careful consideration. We developed methods for constraining OH radical exposure in the OFR during vehicle exhaust oxidation experiments. We observe changes in O/C ratios and highly functionalized species over the temperature gradient employed in the aerosol-CIMS measurement. We relate this observed, speciated chemistry to the volatility of the aerosol, and compare observed SOA yields to other OFR and smog chamber SOA generation methods. Additionally, estimates of OH radical exposure in the OFR during different vehicle experiments of varying fuel type and speed were observed to vary as determined from a high-NOx and variable humidity calibration set.

A compact fiber optics-based heterodyne combined normal and transverse displacement interferometer.

PubMed

Zuanetti, Bryan; Wang, Tianxue; Prakash, Vikas

2017-03-01

While Photonic Doppler Velocimetry (PDV) has become a common diagnostic tool for the measurement of normal component of particle motion in shock wave experiments, this technique has not yet been modified for the measurement of combined normal and transverse motion, as needed in oblique plate impact experiments. In this paper, we discuss the design and implementation of a compact fiber-optics-based heterodyne combined normal and transverse displacement interferometer. Like the standard PDV, this diagnostic tool is assembled using commercially available telecommunications hardware and uses a 1550 nm wavelength 2 W fiber-coupled laser, an optical focuser, and single mode fibers to transport light to and from the target. Two additional optical probes capture first-order beams diffracted from a reflective grating at the target free-surface and deliver the beams past circulators and a coupler where the signal is combined to form a beat frequency. The combined signal is then digitized and analyzed to determine the transverse component of the particle motion. The maximum normal velocity that can be measured by this system is limited by the equivalent transmission bandwidth (3.795 GHz) of the combined detector, amplifier, and digitizer and is estimated to be ∼2.9 km/s. Sample symmetric oblique plate-impact experiments are performed to demonstrate the capability of this diagnostic tool in the measurement of the combined normal and transverse displacement particle motion.

Fluorescence particle detection using microfluidics and planar optoelectronic elements

NASA Astrophysics Data System (ADS)

Kettlitz, Siegfried W.; Moosmann, Carola; Valouch, Sebastian; Lemmer, Uli

2014-05-01

Detection of fluorescent particles is an integral part of flow cytometry for analysis of selectively stained cells. Established flow cytometer designs achieve great sensitivity and throughput but require bulky and expensive components which prohibit mass production of small single-use point-of-care devices. The use of a combination of innovative technologies such as roll-to-roll printed microuidics with integrated optoelectronic components such as printed organic light emitting diodes and printed organic photodiodes enables tremendous opportunities in cost reduction, miniaturization and new application areas. In order to harvest these benefits, the optical setup requires a redesign to eliminate the need for lenses, dichroic mirrors and lasers. We investigate the influence of geometric parameters on the performance of a thin planar design which uses a high power LED as planar light source and a PIN-photodiode as planar detector. Due to the lack of focusing optics and inferior optical filters, the device sensitivity is not yet on par with commercial state of the art flow cytometer setups. From noise measurements, electronic and optical considerations we deduce possible pathways of improving the device performance. We identify that the sensitivity is either limited by dark noise for very short apertures or by noise from background light for long apertures. We calculate the corresponding crossover length. For the device design we conclude that a low device thickness, low particle velocity and short aperture length are necessary to obtain optimal sensitivity.

Characterizing physical properties and heterogeneous chemistry of single particles in air using optical trapping-Raman spectroscopy

NASA Astrophysics Data System (ADS)

Gong, Z.; Wang, C.; Pan, Y. L.; Videen, G.

2017-12-01

Heterogeneous reactions of solid particles in a gaseous environment are of increasing interest; however, most of the heterogeneous chemistry studies of airborne solids were conducted on particle ensembles. A close examination on the heterogeneous chemistry between single particles and gaseous-environment species is the key to elucidate the fundamental mechanisms of hydroscopic growth, cloud nuclei condensation, secondary aerosol formation, etc., and reduce the uncertainty of models in radiative forcing, climate change, and atmospheric chemistry. We demonstrate an optical trapping-Raman spectroscopy (OT-RS) system to study the heterogeneous chemistry of the solid particles in air at single-particle level. Compared to other single-particle techniques, optical trapping offers a non-invasive, flexible, and stable method to isolate single solid particle from substrates. Benefited from two counter-propagating hollow beams, the optical trapping configuration is adaptive to trap a variety of particles with different materials from inorganic substitution (carbon nanotubes, silica, etc.) to organic, dye-doped polymers and bioaerosols (spores, pollen, etc.), with different optical properties from transparent to strongly absorbing, with different sizes from sub-micrometers to tens of microns, or with distinct morphologies from loosely packed nanotubes to microspheres and irregular pollen grains. The particles in the optical trap may stay unchanged, surface degraded, or optically fragmented according to different laser intensity, and their physical and chemical properties are characterized by the Raman spectra and imaging system simultaneously. The Raman spectra is able to distinguish the chemical compositions of different particles, while the synchronized imaging system can resolve their physical properties (sizes, shapes, morphologies, etc.). The temporal behavior of the trapped particles also can be monitored by the OT-RS system at an indefinite time with a resolution from 10 ms to 5 min, which can be further applied to monitor the dynamics of heterogeneous reactions. The OT-RS system provides a flexible method to characterize and monitor the physical properties and heterogeneous chemistry of optically trapped solid particles in gaseous environment at single-particle level.

Anti-Brownian ELectrokinetic (ABEL) Trapping of Single High Density Lipoprotein (HDL) Particles

NASA Astrophysics Data System (ADS)

Bockenhauer, Samuel; Furstenberg, Alexandre; Wang, Quan; Devree, Brian; Jie Yao, Xiao; Bokoch, Michael; Kobilka, Brian; Sunahara, Roger; Moerner, W. E.

2010-03-01

The ABEL trap is a novel device for trapping single biomolecules in solution for extended observation. The trap estimates the position of a fluorescently-labeled object as small as ˜10 nm in solution and then applies a feedback electrokinetic drift every 20 us to trap the object by canceling its Brownian motion. We use the ABEL trap to study HDL particles at the single-copy level. HDL particles, essential in regulation of ``good'' cholesterol in humans, comprise a small (˜10 nm) lipid bilayer disc bounded by a belt of apolipoproteins. By engineering HDL particles with single fluorescent donor/acceptor probes and varying lipid compositions, we are working to study lipid diffusion on small length scales. We also use HDL particles as hosts for single transmembrane receptors, which should enable study of receptor conformational dynamics on long timescales.

Method to separate lignin-rich solid phase from acidic biomass suspension at an acidic pH

DOEpatents

Yasarla, Kumar Lakshmi Rakesh; Ramarao, Bandaru V; Amidon, Thomas

2017-09-05

A method of separating a lignin-rich solid phase from a solution suspension, by pretreating a lignocellulosic biomass with a pretreatment fluid having remove soluble components, colloidal material and primarily lignin containing particles; separating the pretreated lignocellulosic biomass from the pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles; flocculating the separated pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles using polyethylene oxide (i.e., PEO) or cationic Poly acrylamide (i.e., CPAM) as a flocculating agent; and filtering the flocculated separated pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles to remove agglomerates.

Shock-induced microstructural response of mono- and nanocrystalline SiC ceramics

NASA Astrophysics Data System (ADS)

Branicio, Paulo S.; Zhang, Jingyun; Rino, José P.; Nakano, Aiichiro; Kalia, Rajiv K.; Vashishta, Priya

2018-04-01

The dynamic behavior of mono- and nanocrystalline SiC ceramics under plane shock loading is revealed using molecular-dynamics simulations. The generation of shock-induced elastic compression, plastic deformation, and structural phase transformation is characterized at different crystallographic directions as well as on a 5-nm grain size nanostructure at 10 K and 300 K. Shock profiles are calculated in a wide range of particle velocities 0.1-6.0 km/s. The predicted Hugoniot agree well with experimental data. Results indicate the generation of elastic waves for particle velocities below 0.8-1.9 km/s, depending on the crystallographic direction. In the intermediate range of particle velocities between 2 and 5 km/s, the shock wave splits into an elastic precursor and a zinc blende-to-rock salt structural transformation wave, which is triggered by shock pressure over the ˜90 GPa threshold value. A plastic wave, with a strong deformation twinning component, is generated ahead of the transformation wave for shocks in the velocity range between 1.5 and 3 km/s. For particle velocities greater than 5-6 km/s, a single overdriven transformation wave is generated. Surprisingly, shocks on the nanocrystalline sample reveal the absence of wave splitting, and elastic, plastic, and transformation wave components are seamlessly connected as the shock strength is continuously increased. The calculated strengths 15.2, 31.4, and 30.9 GPa for ⟨001⟩, ⟨111⟩, and ⟨110⟩ directions and 12.3 GPa for the nanocrystalline sample at the Hugoniot elastic limit are in excellent agreement with experimental data.

Detector Simulations with DD4hep

NASA Astrophysics Data System (ADS)

Petrič, M.; Frank, M.; Gaede, F.; Lu, S.; Nikiforou, N.; Sailer, A.

2017-10-01

Detector description is a key component of detector design studies, test beam analyses, and most of particle physics experiments that require the simulation of more and more different detector geometries and event types. This paper describes DD4hep, which is an easy-to-use yet flexible and powerful detector description framework that can be used for detector simulation and also extended to specific needs for a particular working environment. Linear collider detector concepts ILD, SiD and CLICdp as well as detector development collaborations CALICE and FCal have chosen to adopt the DD4hep geometry framework and its DDG4 pathway to Geant4 as its core simulation and reconstruction tools. The DDG4 plugins suite includes a wide variety of input formats, provides access to the Geant4 particle gun or general particles source and allows for handling of Monte Carlo truth information, eg. by linking hits and the primary particle that caused them, which is indispensable for performance and efficiency studies. An extendable array of segmentations and sensitive detectors allows the simulation of a wide variety of detector technologies. This paper shows how DD4hep allows to perform complex Geant4 detector simulations without compiling a single line of additional code by providing a palette of sub-detector components that can be combined and configured via compact XML files. Simulation is controlled either completely via the command line or via simple Python steering files interpreted by a Python executable. It also discusses how additional plugins and extensions can be created to increase the functionality.

New Mechanism of Extractive Electrospray Ionization Mass Spectrometry for Heterogeneous Solid Particles.

PubMed

Kumbhani, S; Longin, T; Wingen, L M; Kidd, C; Perraud, V; Finlayson-Pitts, B J

2018-02-06

Real-time in situ mass spectrometry analysis of airborne particles is important in several applications, including exposure studies in ambient air, industrial settings, and assessing impacts on visibility and climate. However, obtaining molecular and 3D structural information is more challenging, especially for heterogeneous solid or semisolid particles. We report a study of extractive electrospray ionization mass spectrometry (EESI-MS) for the analysis of solid particles with an organic coating. The goal is to elucidate how much of the overall particle content is sampled, and determine the sensitivity of this technique to the surface layers. It is shown that, for NaNO 3 particles coated with glutaric acid (GA), very little of the solid NaNO 3 core is sampled compared to the GA coating, whereas for GA particles coated with malonic acid (MA), significant signals from both the MA coating and the GA core are observed. However, conventional ESI-MS of the same samples collected on a Teflon filter (and then extracted) detects much more core material compared to EESI-MS in both cases. These results show that, for the experimental conditions used here, EESI-MS does not sample the entire particle but, instead, is more sensitive to surface layers. Separate experiments on single-component particles of NaNO 3 , GA, or citric acid show that there must be a kinetics limitation to dissolution that is important in determining EESI-MS sensitivity. We propose a new mechanism of EESI solvent droplet interaction with solid particles that is consistent with the experimental observations. In conjunction with previous EESI-MS studies of organic particles, these results suggest that EESI does not necessarily sample the entire particle when solid, and that not only solubility but also surface energies and the kinetics of dissolution play an important role.

Excitation wavelength dependence of the fluorescence kinetics in Photosystem I particles from Synechocystis PCC 6803 and Synechococcus elongatus.

PubMed

Gobets, Bas; van Stokkum, Ivo H M; van Mourik, Frank; Dekker, Jan P; van Grondelle, Rienk

2003-12-01

The excitation-wavelength dependence of the excited-state dynamics of monomeric and trimeric Photosystem I (PSI) particles from Synechocystis PCC 6803 as well as trimeric PSI particles from Synechococcus elongatus has been studied at room temperature using time-resolved fluorescence spectroscopy. For aselective (400 nm), carotenoid (505 nm), and bulk chlorophyll (approximately 650 nm) excitation in all species, a downhill energy-transfer component is observed, corresponding to a lifetime of 3.4-5.5 ps. For selective red excitation (702-719 nm) in all species, a significantly faster, an approximately 1-ps, uphill transfer component was recorded. In Synechococcus PSI, an additional approximately 10-ps downhill energy-transfer component is found for all wavelengths of excitation, except 719 nm. Each of the species exhibits its own characteristic trap spectrum, the shape of which is independent of the wavelength of excitation. This trap spectrum decays in approximately 23 ps in both monomeric and trimeric Synechocystis PSI and in approximately 35 ps in trimeric Synechococcus PSI. The data were simulated based on the 2.5 A structural model of PSI of Synechococcus elongatus using the Förster equation for energy transfer, and using the 0.6-1-ps charge-separation time and the value of 1.2-1.3 for the index of refraction that were obtained from the dynamics of a hypothetical PSI particle without red chls. The experimentally obtained lifetimes and spectra were reproduced well by assigning three of the chlorophyll-a (chla) dimers observed in the structure to the C708/C702RT pool of red chls present in PSI from both species. Essential for the simulation of the dynamics of Synechococcus PSI is the assignment of the single chla trimer in the structure to the C719/C708RT pool present in this species.

Single-protein detection in crowded molecular environments in cryo-EM images

PubMed Central

Rickgauer, J Peter; Grigorieff, Nikolaus; Denk, Winfried

2017-01-01

We present an approach to study macromolecular assemblies by detecting component proteins’ characteristic high-resolution projection patterns, calculated from their known 3D structures, in single electron cryo-micrographs. Our method detects single apoferritin molecules in vitreous ice with high specificity and determines their orientation and location precisely. Simulations show that high spatial-frequency information and—in the presence of protein background—a whitening filter are essential for optimal detection, in particular for images taken far from focus. Experimentally, we could detect small viral RNA polymerase molecules, distributed randomly among binding locations, inside rotavirus particles. Based on the currently attainable image quality, we estimate a threshold for detection that is 150 kDa in ice and 300 kDa in 100 nm thick samples of dense biological material. DOI: http://dx.doi.org/10.7554/eLife.25648.001 PMID:28467302

Modeling the effects of low-LET cosmic rays on electronic components.

PubMed

Keating, A; Goncalves, P; Pimenta, M; Brogueira, P; Zadeh, A; Daly, E

2012-08-01

The effects of cosmic radiation in single cells, organic tissues and electronics are a major concern for space exploration and manned missions. Standard heavy ions radiation tests employ ion cocktails with energy of the order of 10 MeV per nucleon and with a linear energy transfer ranging from a few MeV cm(2) mg(-1) to hundreds of MeV cm(2) mg(-1). In space, cosmic rays show significant fluxes at energies up to the order of GeV per nucleon. The present work aims at investigating single event damage due to low-, high- and very-high-energy ions. The European Space Agency reference single event upset monitor data are used to support the discussion. Finally, the effect of ionization induced directly by primary particles and ionization induced by recoils produced in an electronic device is investigated for different types of devices.

Opto-electrochemical In Situ Monitoring of the Cathodic Formation of Single Cobalt Nanoparticles.

PubMed

Brasiliense, Vitor; Clausmeyer, Jan; Dauphin, Alice L; Noël, Jean-Marc; Berto, Pascal; Tessier, Gilles; Schuhmann, Wolfgang; Kanoufi, Fréderic

2017-08-21

Single-particle electrochemistry at a nanoelectrode is explored by dark-field optical microscopy. The analysis of the scattered light allows in situ dynamic monitoring of the electrodeposition of single cobalt nanoparticles down to a radius of 65 nm. Larger sub-micrometer particles are directly sized optically by super-localization of the edges and the scattered light contains complementary information concerning the particle redox chemistry. This opto-electrochemical approach is used to derive mechanistic insights about electrocatalysis that are not accessible from single-particle electrochemistry. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of high-energy particles on accretion flows onto a super massive black hole

NASA Astrophysics Data System (ADS)

Kimura, Shigeo

We study effects of high-energy particles on the accretion flow onto a supermassive black hole and luminosities of escaping particles such as protons, neutrons, gamma-rays, and neutrinos. We formulate a one-dimensional model of the two-component accretion flow consisting of thermal particles and high-energy particles, supposing that some fraction of viscous dissipation energy is converted to the acceleration of high-energy particles. The thermal component is governed by fluid dynamics while the high-energy particles obey the moment equations of the diffusion-convection equation. By solving the time evolution of these equations, we obtain advection dominated flows as steady state solutions. Effects of the high-energy particles on the flow structure turn out to be very small because the compressional heating is so effective that the thermal component always provides the major part of the pressure. We calculate luminosities of escaping particles for these steady solutions. For a broad range of mass accretion rates, escaping particles can extract the energy about one-thousandth of the accretion energy. We also discuss some implications on relativistic jet production by escaping particles.

Chemical ageing and transformation of diffusivity in semi-solid multi-component organic aerosol particles

NASA Astrophysics Data System (ADS)

Pfrang, C.; Shiraiwa, M.; Pöschl, U.

2011-04-01

Recent experimental evidence underlines the importance of reduced diffusivity in amorphous semi-solid or glassy atmospheric aerosols. This paper investigates the impact of diffusivity on the ageing of multi-component reactive organic particles representative of atmospheric cooking aerosols. We apply and extend the recently developed KM-SUB model in a study of a 12-component mixture containing oleic and palmitoleic acids. We demonstrate that changes in the diffusivity may explain the evolution of chemical loss rates in ageing semi-solid particles, and we resolve surface and bulk processes under transient reaction conditions considering diffusivities altered by oligomerisation. This new model treatment allows prediction of the ageing of mixed organic multi-component aerosols over atmospherically relevant time scales and conditions. We illustrate the impact of changing diffusivity on the chemical half-life of reactive components in semi-solid particles, and we demonstrate how solidification and crust formation at the particle surface can affect the chemical transformation of organic aerosols.

Chemical ageing and transformation of diffusivity in semi-solid multi-component organic aerosol particles

NASA Astrophysics Data System (ADS)

Pfrang, C.; Shiraiwa, M.; Pöschl, U.

2011-07-01

Recent experimental evidence underlines the importance of reduced diffusivity in amorphous semi-solid or glassy atmospheric aerosols. This paper investigates the impact of diffusivity on the ageing of multi-component reactive organic particles approximating atmospheric cooking aerosols. We apply and extend the recently developed KM-SUB model in a study of a 12-component mixture containing oleic and palmitoleic acids. We demonstrate that changes in the diffusivity may explain the evolution of chemical loss rates in ageing semi-solid particles, and we resolve surface and bulk processes under transient reaction conditions considering diffusivities altered by oligomerisation. This new model treatment allows prediction of the ageing of mixed organic multi-component aerosols over atmospherically relevant timescales and conditions. We illustrate the impact of changing diffusivity on the chemical half-life of reactive components in semi-solid particles, and we demonstrate how solidification and crust formation at the particle surface can affect the chemical transformation of organic aerosols.

Fuzzy Logic Particle Tracking

NASA Technical Reports Server (NTRS)

2005-01-01

A new all-electronic Particle Image Velocimetry technique that can efficiently map high speed gas flows has been developed in-house at the NASA Lewis Research Center. Particle Image Velocimetry is an optical technique for measuring the instantaneous two component velocity field across a planar region of a seeded flow field. A pulsed laser light sheet is used to illuminate the seed particles entrained in the flow field at two instances in time. One or more charged coupled device (CCD) cameras can be used to record the instantaneous positions of particles. Using the time between light sheet pulses and determining either the individual particle displacements or the average displacement of particles over a small subregion of the recorded image enables the calculation of the fluid velocity. Fuzzy logic minimizes the required operator intervention in identifying particles and computing velocity. Using two cameras that have the same view of the illumination plane yields two single exposure image frames. Two competing techniques that yield unambiguous velocity vector direction information have been widely used for reducing the single-exposure, multiple image frame data: (1) cross-correlation and (2) particle tracking. Correlation techniques yield averaged velocity estimates over subregions of the flow, whereas particle tracking techniques give individual particle velocity estimates. For the correlation technique, the correlation peak corresponding to the average displacement of particles across the subregion must be identified. Noise on the images and particle dropout result in misidentification of the true correlation peak. The subsequent velocity vector maps contain spurious vectors where the displacement peaks have been improperly identified. Typically these spurious vectors are replaced by a weighted average of the neighboring vectors, thereby decreasing the independence of the measurements. In this work, fuzzy logic techniques are used to determine the true correlation displacement peak even when it is not the maximum peak, hence maximizing the information recovery from the correlation operation, maintaining the number of independent measurements, and minimizing the number of spurious velocity vectors. Correlation peaks are correctly identified in both high and low seed density cases. The correlation velocity vector map can then be used as a guide for the particle-tracking operation. Again fuzzy logic techniques are used, this time to identify the correct particle image pairings between exposures to determine particle displacements, and thus the velocity. Combining these two techniques makes use of the higher spatial resolution available from the particle tracking. Particle tracking alone may not be possible in the high seed density images typically required for achieving good results from the correlation technique. This two-staged velocimetric technique can measure particle velocities with high spatial resolution over a broad range of seeding densities.

Detecting element specific electrons from a single cobalt nanocluster with synchrotron x-ray scanning tunneling microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kersell, Heath; Shirato, Nozomi; Cummings, Marvin

We use a nanofabricated scanning tunneling microscope tip as a detector to investigate local X-ray induced tunneling and electron emission from a single cobalt nanocluster on a Au(111) surface. The tip-detector is positioned a few angstroms above the nanocluster, and ramping the incident X-ray energy across the Co photoabsorption K-edge enables the detection of element specific electrons. Atomic-scale spatial dependent changes in the X-ray absorption cross section are directly measured by taking the X-ray induced current as a function of X-ray energy. From the measured sample and tip currents, element specific X-ray induced current components can be separated and therebymore » the corresponding yields for the X-ray induced processes of the single cobalt nanocluster can be determined. The detection of element specific synchrotron X-ray induced electrons of a single nanocluster opens a new avenue for materials characterization on a one particle at-a-time basis.« less

Detecting element specific electrons from a single cobalt nanocluster with synchrotron x-ray scanning tunneling microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kersell, Heath; Shirato, Nozomi; Cummings, Marvin

Here, we use a nanofabricated scanning tunneling microscope tip as a detector to investigate local X-ray induced tunneling and electron emission from a single cobalt nanocluster on a Au(111) surface. The tip-detector is positioned a few angstroms above the nanocluster, and ramping the incident X-ray energy across the Co photoabsorption K-edge enables the detection of element specific electrons. Atomic-scale spatial dependent changes in the X-ray absorption cross section are directly measured by taking the X-ray induced current as a function of X-ray energy. From the measured sample and tip currents, element specific X-ray induced current components can be separated andmore » thereby the corresponding yields for the X-ray induced processes of the single cobalt nanocluster can be determined. The detection of element specific synchrotron X-ray induced electrons of a single nanocluster opens a new avenue for materials characterization on a one particle at-a-time basis.« less

Detecting element specific electrons from a single cobalt nanocluster with synchrotron x-ray scanning tunneling microscopy

DOE PAGES

Kersell, Heath; Shirato, Nozomi; Cummings, Marvin; ...

2017-09-05

Here, we use a nanofabricated scanning tunneling microscope tip as a detector to investigate local X-ray induced tunneling and electron emission from a single cobalt nanocluster on a Au(111) surface. The tip-detector is positioned a few angstroms above the nanocluster, and ramping the incident X-ray energy across the Co photoabsorption K-edge enables the detection of element specific electrons. Atomic-scale spatial dependent changes in the X-ray absorption cross section are directly measured by taking the X-ray induced current as a function of X-ray energy. From the measured sample and tip currents, element specific X-ray induced current components can be separated andmore » thereby the corresponding yields for the X-ray induced processes of the single cobalt nanocluster can be determined. The detection of element specific synchrotron X-ray induced electrons of a single nanocluster opens a new avenue for materials characterization on a one particle at-a-time basis.« less

Energetic particle modes of q = 1 high-order harmonics in tokamak plasmas with monotonic weak magnetic shear

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, Zhen-Zhen; Wang, Feng; Fu, G. Y.

Linear and nonlinear simulations of high-order harmonics q=1 energetic particle modes excited by trapped energetic particles in tokamaks are carried out using kinetic/magnetohydrodynamic hybrid code M3D-K. It is found that with a flat safety factor profile in the core region, the linear growth rate of high-order harmonics (m=n>1) driven by energetic trapped particles can be higher than the m/n=1/1 component. The high m=n>1 modes become more unstable when the pressure of energetic particles becomes higher. Moreover, it is shown that there exist multiple resonant locations satisfying different resonant conditions in the phase space of energetic particles for the high-order harmonicsmore » modes, whereas there is only one precessional resonance for the m/n=1/1 harmonics. The fluid nonlinearity reduces the saturation level of the n=1 component, while it hardly affects those of the high n components, especially the modes with m=n=3,4. The frequency of these modes does not chirp significantly, which is different with the typical fishbone driven by trapped particles. Lastly, in addition, the flattening region of energetic particle distribution due to high-order harmonics excitation is wider than that due to m/n=1/1 component, although the m/n=1/1 component has a higher saturation amplitude.« less

Energetic particle modes of q = 1 high-order harmonics in tokamak plasmas with monotonic weak magnetic shear

DOE PAGES

Ren, Zhen-Zhen; Wang, Feng; Fu, G. Y.; ...

2017-04-24

Linear and nonlinear simulations of high-order harmonics q=1 energetic particle modes excited by trapped energetic particles in tokamaks are carried out using kinetic/magnetohydrodynamic hybrid code M3D-K. It is found that with a flat safety factor profile in the core region, the linear growth rate of high-order harmonics (m=n>1) driven by energetic trapped particles can be higher than the m/n=1/1 component. The high m=n>1 modes become more unstable when the pressure of energetic particles becomes higher. Moreover, it is shown that there exist multiple resonant locations satisfying different resonant conditions in the phase space of energetic particles for the high-order harmonicsmore » modes, whereas there is only one precessional resonance for the m/n=1/1 harmonics. The fluid nonlinearity reduces the saturation level of the n=1 component, while it hardly affects those of the high n components, especially the modes with m=n=3,4. The frequency of these modes does not chirp significantly, which is different with the typical fishbone driven by trapped particles. Lastly, in addition, the flattening region of energetic particle distribution due to high-order harmonics excitation is wider than that due to m/n=1/1 component, although the m/n=1/1 component has a higher saturation amplitude.« less

Extinction cross section measurements for a single optically trapped particle

NASA Astrophysics Data System (ADS)

Cotterell, Michael I.; Preston, Thomas C.; Mason, Bernard J.; Orr-Ewing, Andrew J.; Reid, Jonathan P.

2015-08-01

Bessel beam (BB) optical traps have become widely used to confine single and multiple aerosol particles across a broad range of sizes, from a few microns to < 200 nm in radius. The radiation pressure force exerted by the core of a single, zeroth-order BB incident on a particle can be balanced by a counter-propagating gas flow, allowing a single particle to be trapped indefinitely. The pseudo non-diffracting nature of BBs enables particles to be confined over macroscopic distances along the BB core propagation length; the position of the particle along this length can be finely controlled by variation of the BB laser power. This latter property is exploited to optimize the particle position at the center of the TEM00 mode of a high finesse optical cavity, allowing cavity ring-down spectroscopy (CRDS) to be performed on single aerosol particles and their optical extinction cross section, σext, measured. Further, the variation in the light from the illuminating BB elastically scattered by the particle is recorded as a function of scattering angle. Such intensity distributions are fitted to Lorenz-Mie theory to determine the particle radius. The trends in σext with particle radius are modelled using cavity standing wave Mie simulations and a particle's varying refractive index with changing relative humidity is determined. We demonstrate σext measurements on individual sub-micrometer aerosol particles and determine the lowest limit in particle size that can be probed by this technique. The BB-CRDS method will play a key role in reducing the uncertainty associated with atmospheric aerosol radiative forcing, which remains among the largest uncertainties in climate modelling.

Weight of Polyethylene Wear Particles is Similar in TKAs with Oxidized Zirconium and Cobalt-chrome Prostheses

PubMed Central

Kim, Jun-Shik; Huh, Wansoo; Lee, Kwang-Hoon

2009-01-01

Background The greater lubricity and resistance to scratching of oxidized zirconium femoral components are expected to result in less polyethylene wear than cobalt-chrome femoral components. Questions/purposes We examined polyethylene wear particles in synovial fluid and compared the weight, size (equivalent circle diameter), and shape (aspect ratio) of polyethylene wear particles in knees with an oxidized zirconium femoral component with those in knees with a cobalt-chrome femoral component. Patients and Methods One hundred patients received an oxidized zirconium femoral component in one knee and a cobalt-chrome femoral component in the other. There were 73 women and 27 men with a mean age of 55.6 years (range, 44–60 years). The minimum followup was 5 years (mean, 5.5 years; range, 5–6 years). Polyethylene wear particles were analyzed using thermogravimetric methods and scanning electron microscopy. Results The weight of polyethylene wear particles produced at the bearing surface was 0.0223 ± 0.0054 g in 1 g synovial fluid in patients with an oxidized zirconium femoral component and 0.0228 ± 0.0062 g in patients with a cobalt-chrome femoral component. Size and shape of polyethylene wear particles were 0.59 ± 0.05 μm and 1.21 ± 0.24, respectively, in the patients with an oxidized zirconium femoral component and 0.52 ± 0.03 μm and 1.27 ± 0.31, respectively, in the patients with a cobalt-chrome femoral component. Knee Society knee and function scores, radiographic results, and complication rate were similar between the knees with an oxidized zirconium and cobalt-chrome femoral component. Conclusions The weight, size, and shape of polyethylene wear particles were similar in the knees with an oxidized zirconium and a cobalt-chrome femoral component. We found the theoretical advantages of this surface did not provide the actual advantage. Level of Evidence Level I, therapeutic study. See the guidelines for Authors for a complete description of levels of evidence. PMID:19949906

Features of the phase composition and morphology of the particles of sialon synthesized from silicon and aluminum nitrides

NASA Astrophysics Data System (ADS)

Ivicheva, S. N.; Lysenkov, A. S.; Ovsyannikov, N. A.; Titov, D. D.; Kargin, Yu F.

2018-04-01

The phase composition and morphological features of sialons were studied under the same conditions of firing (duration, temperature) using different initial components, silicon nitride, aluminum nitride, and a mixture of silicon nitrides and aluminum with the application of nitrides of the corresponding oxide (aluminum or silicon) sol-gel method. The effect of the initial reagents composition on the phase composition of the final product and the morphological features of the sialon powders obtained in a single firing step in a nitrogen atmosphere is shown.

Ultrasonic measurement of stress in 2219-T87 aluminum plate

NASA Technical Reports Server (NTRS)

Clotfelter, W. N.; Risch, E. R.

1976-01-01

The basic relationship of ultrasonic signal velocity to directional subsurface stress is reviewed. Inappropriateness of dependency on a single correlative value of constant for a three dimensional stress field in metallic materials is discussed. Implementation of conventional ultrasonic nondestructive testing capabilities integrated to provide a composite technique for the measurement of orthogonal stress components is described, and the procedures for performing the preparatory calibration and subsequent stress field measurements are presented. In conclusion, the prime effect of stress on ultrasonic signal velocity occurs only in the direction of material excitation or particle motion.

Demixing in symmetric supersolid mixtures

NASA Astrophysics Data System (ADS)

Jain, Piyush; Moroni, Saverio; Boninsegni, Massimo; Pollet, Lode

2013-09-01

The droplet crystal phase of a symmetric binary mixture of soft-core bosons is studied by computer simulation. At high temperature each droplet comprises on average equal numbers of particles of either component, but the two components demix below the supersolid transition temperature, i.e., droplets mostly consist of particles of one component. Clustering of droplets of the same component is also observed. Demixing is driven by quantum tunneling of particles across droplets over the system and does not take place in an insulating crystal. This effect provides an unambiguous experimental signature of supersolidity.

Plasmonic Resonances for Spectroscopy Applications using 3D Finite-Difference Time-Domain Models

NASA Astrophysics Data System (ADS)

Ravi, Aruna

Tuning plasmonic extinction resonances of sub-wavelength scale structures is essential to achieve maximum sensitivity and accuracy. These resonances can be controlled with careful design of nanoparticle geometries and incident wave attributes. In the first part of this dissertation, plasmonically enhanced effects on hexagonal-arrays of metal nanoparticles, metal-hole arrays (micro-mesh), and linear-arrays of metal nanorings are analyzed using three-dimensional Finite-Difference Time-Domain (3D-FDTD) simulations. The effect of particle size, lattice spacing, and lack of monodispersity of a self-assembled, hexagonal array layer of silver (Ag) nanoparticles on the extinction resonance is investigated to help determine optimal design specifications for efficient organic solar power harvesting. The enhancement of transmission resonances using plasmonic thin metal films with arrays of holes which enable recording of scatter-free infrared (IR) transmission spectra of individual particles is also explored. This method is quantitative, non-destructive and helps in better understanding the interaction of light with sub-wavelength particles. Next, plasmonically enhanced effects on linear arrays of gold (Au) rings are studied. Simulations employing 3D-FDTD can be used to determine the set of geometrical parameters to attain localized surface plasmon resonance (LSPR). The shifts in resonances due to changes in the effective dielectric of the structure are investigated, which is useful in sensing applications. Computational models enrich experimental studies. In the second part of this dissertation, the effect of particle size, shape and orientation on the IR spectra is investigated using 3D-FDTD and Mie-Bruggeman models. This computational analysis is extended to include clusters of particles of mixed composition. The prediction of extinction and absorption spectra of single particles of mixed composition helps in interpreting their physical properties and predict chemical composition. The chemical composition of respirable particles is of great interest from health, atmospheric, and environmental perspectives. Different environments may pose different hazards and spectroscopic challenges. Common mineral components of airborne and atmospheric dust samples have strong IR transitions with wavelengths that match particle size, giving rise to interesting lineshape distortions. These models enable the determination of volume fractions of components in individual particles that are mixtures of many materials, as are the dust particles inhaled into people's lungs.

Accurate modelling of single-particle cryo-EM images quantifies the benefits expected from using Zernike phase contrast

PubMed Central

Hall, R. J.; Nogales, E.; Glaeser, R. M.

2011-01-01

The use of a Zernike-type phase plate in biological cryo-electron microscopy allows the imaging, without using defocus, of what are predominantly phase objects. It is thought that such phase-plate implementations might result in higher quality images, free from the problems of CTF correction that occur when images must be recorded at extremely high values of defocus. In single-particle cryo-electron microscopy it is hoped that these improvements in image quality will facilitate work on structures that have proved difficult to study, either because of their relatively small size or because the structures are not completely homogeneous. There is still a need, however, to quantify how much improvement can be gained by using a phase plate for single-particle cryo-electron microscopy. We present a method for quantitatively modelling the images recorded with 200 keV electrons, for single particles embedded in vitreous ice. We then investigate what difference the use of a phase-plate device could have on the processing of single-particle data. We confirm that using a phase plate results in single-particle datasets in which smaller molecules can be detected, particles can be more accurately aligned and problems of heterogeneity can be more easily addressed. PMID:21463690

Particle orbits in model current sheet with a nonzero B(y) component

NASA Technical Reports Server (NTRS)

Zhu, Zhongwei; Parks, George

1993-01-01

The problem of charged particle motions in magnetotaillike model current sheets is revisited with the inclusion of a nonzero dawn-dusk magnetic field component. Three cases are examined considering both trapped and escaped orbits. The results show that a nonzero B(y) component disturbs the particle orbits by destroying orbit symmetry in the phase space about the z = 0 plane. It also changes the bounce frequency of particle orbits. The presence of B(y) thus modifies the Speiser orbits, particularly near the ejection phase. The process of ejected particle such as ejection direction, ejection velocity, and pitch angles are shown to depend on the sign of the charge.

Characterization of vertical aerosol flows by single particle mass spectrometry for micrometeorological analysis

NASA Astrophysics Data System (ADS)

Gelhausen, Elmar; Hinz, Klaus-Peter; Schmidt, Andres; Spengler, Bernhard

2011-10-01

A single particle mass spectrometer LAMPAS 2 (Laser Mass Analyzer for Particles in the Airborne State) was combined with an ultrasonic anemometer to provide a measurement system for monitoring environmental substance exchange as caused by emission/deposition of aerosol particles. For this study, 681 mass spectra of detected particles were sorted into groups of similarity by a clustering algorithm leading to five classes of different particle types. Each single mass spectrum was correlated to corresponding anemometer data (vertical wind vector and wind speed) in a time-resolved analysis. Due to sampling constraints time-resolution was limited to 36 s, as a result of transition time distributions through the sampling tube. Vertical particle flow (emission/deposition) was determined for all particles based on these data as acquired during a measuring campaign in Giessen, Germany. For a selected particle class a detailed up- and downwards flow consideration was performed to prove the developed approach. Particle flow of that class was dominated by an emission trend as expected. The presented combination of single-particle mass spectrometry and ultrasonic anemometry provides for the possibility to correlate chemical particle data and wind data in a distinct assignment for the description of turbulent particle behavior near earth surface. Results demonstrate the ability to apply the method to real micrometeorological systems, if sampling issues are properly considered for an intended time resolution.

Martian airfall dust on smooth, inclined surfaces as observed on the Phoenix Mars Lander telltale mirror

NASA Astrophysics Data System (ADS)

Moores, John E.; Ha, Taesung; Lemmon, Mark T.; Gunnlaugsson, Haraldur Páll

2015-10-01

The telltale mirror, a smooth inclined surface raised over 1 m above the deck of the Phoenix Mars Lander, was observed by the Surface Stereo Imager (SSI) several times per sol during the Phoenix Mars Lander mission. These observations were combined with a radiative transfer model to determine the thickness of dust on the wind telltale mirror as a function of time. 239 telltale sequences were analyzed and dustiness was determined on a diurnal and seasonal basis. The thickness of accumulated dust did not follow any particular diurnal or seasonal trend. The dust thickness on the mirror over the mission was 0.82±0.39 μm, which suggests a similar thickness to the modal scattering particle diameter. This suggests that inclining a surface beyond the angle of repose and polishing it to remove surface imperfections is an effective way to mitigate the accumulation of dust to less than a micron over a wide range of meteorological conditions and could be beneficial for surfaces which can tolerate some dust but not thick accumulations, such as solar panels. However, such a surface will not remain completely dust free through this action alone and mechanical or electrical clearing must be employed to remove adhered dust if a pristine surface is required. The single-scattering phase function of the dust on the mirror was consistent with the single-scattering phase function of martian aerosol dust at 450 nm, suggesting that this result is inconsistent with models of the atmosphere which require vertically or horizontally separated components or broad size distributions to explain the scattering behavior of these aerosols in the blue. The single-scattering behavior of the dust on the mirror is also consistent with Hapke modeling of spherical particles. The presence of a monolayer of particles would tend to support the spherical conclusion: such particles would be most strongly adhered electrostatically.

Molecular Diversity of Sea Spray Aerosol Particles: Impact of Ocean Biology on Particle Composition and Hygroscopicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cochran, Richard E.; Laskina, Olga; Trueblood, Jonathan V.

The impact of sea spray aerosol (SSA) on climate depends on the size and chemical composition of individual particles that make-up the total SSA ensemble. While the organic fraction of SSA has been characterized from a bulk perspective, there remains a lack of understanding as to the composition of individual particles within the SSA ensemble. To better understand the molecular components within SSA particles and how SSA composition changes with ocean biology, simultaneous measurements of seawater and SSA were made during a month-long mesocosm experiment performed in an ocean-atmosphere facility. Herein, we deconvolute the composition of freshly emitted SSA devoidmore » of anthropogenic and terrestrial influences by characterizing classes of organic compounds as well as specific molecules within individual SSA particles. Analysis of SSA particles show that the diversity of molecules within the organic fraction varies between two size fractions (submicron and supermicron) with contributions from fatty acids, monosaccharides, polysaccharides and siliceous material. Significant changes in the distribution of these compounds within individual particles are observed to coincide with the rise and fall of phytoplankton and bacterial populations within the seawater. Furthermore, water uptake is impacted as shown by hygroscopicity measurements of model systems composed of representative organic compounds. Thus, the how changes in the hygroscopic growth of SSA evolves with composition can be elucidated. Overall, this study provides an important connection between biological processes that control the composition of seawater and changes in single particle composition which will enhances our ability to predict the impact of SSA on climate.« less

Embedded Fiber Optic Sensors for Measuring Transient Detonation/Shock Behavior;Time-of-Arrival Detection and Waveform Determination.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chavez, Marcus Alexander; Willis, Michael David; Covert, Timothy Todd

2014-09-01

The miniaturization of explosive components has driven the need for a corresponding miniaturization of the current diagnostic techniques available to measure the explosive phenomena. Laser interferometry and the use of spectrally coated optical windows have proven to be an essential interrogation technique to acquire particle velocity time history data in one- dimensional gas gun and relatively large-scale explosive experiments. A new diagnostic technique described herein allows for experimental measurement of apparent particle velocity time histories in microscale explosive configurations and can be applied to shocks/non-shocks in inert materials. The diagnostic, Embedded Fiber Optic Sensors (EFOS), has been tested in challengingmore » microscopic experimental configurations that give confidence in the technique's ability to measure the apparent particle velocity time histories of an explosive with pressure outputs in the tenths of kilobars to several kilobars. Embedded Fiber Optic Sensors also allow for several measurements to be acquired in a single experiment because they are microscopic, thus reducing the number of experiments necessary. The future of EFOS technology will focus on further miniaturization, material selection appropriate for the operating pressure regime, and extensive hydrocode and optical analysis to transform apparent particle velocity time histories into true particle velocity time histories as well as the more meaningful pressure time histories.« less

TAKASAGO-6 apparatus for cryogenic coherent X-ray diffraction imaging of biological non-crystalline particles using X-ray free electron laser at SACLA.

PubMed

Kobayashi, Amane; Sekiguchi, Yuki; Takayama, Yuki; Oroguchi, Tomotaka; Shirahama, Keiya; Torizuka, Yasufumi; Manoda, Masahiro; Nakasako, Masayoshi; Yamamoto, Masaki

2016-05-01

Coherent X-ray diffraction imaging (CXDI) is a technique for structure analyses of non-crystalline particles with dimensions ranging from micrometer to sub-micrometer. We have developed a diffraction apparatus named TAKASAGO-6 for use in single-shot CXDI experiments of frozen-hydrated non-crystalline biological particles at cryogenic temperature with X-ray free electron laser pulses provided at a repetition rate of 30 Hz from the SPring-8 Angstrom Compact free-electron LAser. Specimen particles are flash-cooled after being dispersed on thin membranes supported by specially designed disks. The apparatus is equipped with a high-speed translation stage with a cryogenic pot for raster-scanning of the disks at a speed higher than 25 μm/33 ms. In addition, we use devices assisting the easy transfer of cooled specimens from liquid-nitrogen storages to the cryogenic pot. In the current experimental procedure, more than 20 000 diffraction patterns can be collected within 1 h. Here we report the key components and performance of the diffraction apparatus. Based on the efficiency of the diffraction data collection and the structure analyses of metal particles, biological cells, and cellular organelles, we discuss the future application of this diffraction apparatus for structure analyses of biological specimens.

Spatial Variability in Black Carbon Mixing State Observed During The Multi-City NASA DISCOVER-AQ Field Campaign

NASA Astrophysics Data System (ADS)

Moore, R.; Ziemba, L. D.; Beyersdorf, A. J.; Chen, G.; Corr, C.; Hudgins, C.; Martin, R.; Shook, M.; Thornhill, K. L., II; Winstead, E.; Anderson, B. E.

2014-12-01

Light absorbing carbonaceous aerosols are known to be an important climatic driver with a global radiative forcing of about half (IPCC, 2013) to two-thirds (Bond et al., 2013) that of the dominant greenhouse gas, carbon dioxide. While the mass absorption coefficient of pure black carbon (BC) is fairly well known, observational evidence suggests that BC rapidly mixes with other aerosol chemical components within hours of emission (Moffet and Prather, 2009; Moteki et al., 2007). These other components may include predominantly scattering organic, sulfate, and nitrate species, as well as light-absorbing, so-called "brown carbon" (BrC). It has been suggested that the presence of these BC-mixed components may induce mixing-state-dependent lensing effects that could potentially double the BC direct radiative forcing (Jacobson, 2001). The key to better understanding how BC-rich aerosols are distributed in the atmosphere is to examine an unbiased set of measurements covering broad spatial and temporal coverage; however, many past airborne field campaigns have specifically targeted source plumes or other scientifically-relevant emissions sources. The recent NASA DISCOVER-AQ campaign is unique in that approximately the same flight pattern was performed over a month-long period in each of four different U.S. metropolitan areas, ensuring an unbiased, or at least less biased, data set with both wide horizontal and vertical (surface to 5 km altitude) coverage. We present a statistical analysis of BC-rich particle mixing state measured during DISCOVER-AQ by a DMT Single Particle Soot Photometer (SP2). The SP2 measures the BC mass distribution via laser incandescence, and the non-BC coating thickness is inferred from the light scattering signal of particles greater than 200 nm in diameter (Gao et al., 2007; Moteki and Kondo, 2008). The SP2-derived size distributions are compared to optical scattering size distributions measured by an UHSAS in order determine 1) the externally mixed fraction of particles containing BC across the optically-active region of the size distribution (200-1000 nm) and 2) the internally mixed volume fraction of BC relative to the total particle volume assuming spherical particles. Vertical profiles of these variables are discussed in the context of remotely sensing aerosol mixing state.

Online single particle measurement of fireworks pollution during Chinese New Year in Nanning.

PubMed

Li, Jingyan; Xu, Tingting; Lu, Xiaohui; Chen, Hong; Nizkorodov, Sergey A; Chen, Jianmin; Yang, Xin; Mo, Zhaoyu; Chen, Zhiming; Liu, Huilin; Mao, Jingying; Liang, Guiyun

2017-03-01

Time-resolved single-particle measurements were conducted during Chinese New Year in Nanning, China. Firework displays resulted in a burst of SO 2 , coarse mode, and accumulation mode (100-500nm) particles. Through single particle mass spectrometry analysis, five different types of particles (fireworks-metal, ash, dust, organic carbon-sulfate (OC-sulfate), biomass burning) with different size distributions were identified as primary emissions from firework displays. The fireworks-related particles accounted for more than 70% of the total analyzed particles during severe firework detonations. The formation of secondary particulate sulfate and nitrate during firework events was investigated on single particle level. An increase of sulfite peak (80SO 3 - ) followed by an increase of sulfate peaks (97HSO 4 - +96SO 4 - ) in the mass spectra during firework displays indicated the aqueous uptake and oxidation of SO 2 on particles. High concentration of gaseous SO 2 , high relative humidity and high particle loading likely promoted SO 2 oxidation. Secondary nitrate formed through gas-phase oxidation of NO 2 to nitric acid, followed by the condensation into particles as ammonium nitrate. This study shows that under worm, humid conditions, both primary and secondary aerosols contribute to the particulate air pollution during firework displays. Copyright © 2016. Published by Elsevier B.V.

An overview on the use of backscattered sound for measuring suspended particle size and concentration profiles in non-cohesive inorganic sediment transport studies

NASA Astrophysics Data System (ADS)

Thorne, Peter D.; Hurther, David

2014-02-01

For over two decades, coastal marine scientists studying boundary layer sediment transport processes have been using, and developing, the application of sound for high temporal-spatial resolution measurements of suspended particle size and concentration profiles. To extract the suspended sediment parameters from the acoustic data requires an understanding of the interaction of sound with a suspension of sediments and an inversion methodology. This understanding is distributed around journals in a number of scientific fields and there is no single article that succinctly draws together the different components. In the present work the aim is to provide an overview on the acoustic approach to measuring suspended sediment parameters and assess its application in the study of non-cohesive inorganic suspended sediment transport processes.

Prevalence, pathophysiological mechanisms and factors affecting urolithiasis.

PubMed

Khan, Aslam

2018-05-01

The formation of urinary stone, urolithiasis, is one the oldest known disease affecting human throughout different civilizations and times. The exact pathophysiological mechanism of urolithiasis is not yet clear, as these calculi are of various types and too complex for simple understanding. A single theory cannot explain its formation; therefore, different theories are presented in various times for its explanation like free particle, fixed particle, Randall's plaque theory. In addition, various factors and components are identified that play an important role in the formation of these urinary calculi. In this review, composition of kidney stones, its prevalence/incidence, explanation of pathophysiological mechanisms and role of various factors; urinary pH, uric acid, parathyroid hormone, citrate, oxalate, calcium and macromolecules; osteopontin, matrix Gla protein, kidney injury molecules, urinary prothrombin fragment-1, Tamm-Horsfall protein, inter-α-inhibitors, have been discussed in detail.

Disentangling Random Motion and Flow in a Complex Medium

PubMed Central

Koslover, Elena F.; Chan, Caleb K.; Theriot, Julie A.

2016-01-01

We describe a technique for deconvolving the stochastic motion of particles from large-scale fluid flow in a dynamic environment such as that found in living cells. The method leverages the separation of timescales to subtract out the persistent component of motion from single-particle trajectories. The mean-squared displacement of the resulting trajectories is rescaled so as to enable robust extraction of the diffusion coefficient and subdiffusive scaling exponent of the stochastic motion. We demonstrate the applicability of the method for characterizing both diffusive and fractional Brownian motion overlaid by flow and analytically calculate the accuracy of the method in different parameter regimes. This technique is employed to analyze the motion of lysosomes in motile neutrophil-like cells, showing that the cytoplasm of these cells behaves as a viscous fluid at the timescales examined. PMID:26840734

Source apportionment of lead-containing aerosol particles in Shanghai using single particle mass spectrometry.

PubMed

Zhang, Yaping; Wang, Xiaofei; Chen, Hong; Yang, Xin; Chen, Jianmin; Allen, Jonathan O

2009-01-01

Lead (Pb) in individual aerosol particles was measured using single particle aerosol mass spectrometer (ATOFMS) in the summer of 2007 in Shanghai, China. Pb was found in 3% of particles with diameters in the range 0.1-2.0 microm. Single particle data were analyzed focusing on the particles with high Pb content which were mostly submicron. Using the ART-2a neural network algorithm, these fine Pb-rich particles were classified into eight main classes by their mass spectral patterns. Based on the size distribution, temporal variation of number density, chemical composition and the correlation between different chemical species for each class, three major emission sources were identified. About 45% of the Pb-rich particles contained organic or elemental carbon and were attributed to the emission from coal combustion; particles with good correlation between Cl and Pb content were mostly attributed to waste incineration. One unique class of particles was identified by strong phosphate and Pb signals, which were assigned to emissions from phosphate industry. Other Pb-rich particles included aged sea salt and particles from metallurgical processes.

Computation of Phase Equilibria, State Diagrams and Gas/Particle Partitioning of Mixed Organic-Inorganic Aerosols

NASA Astrophysics Data System (ADS)

Zuend, A.; Marcolli, C.; Peter, T.

2009-04-01

The chemical composition of organic-inorganic aerosols is linked to several processes and specific topics in the field of atmospheric aerosol science. Photochemical oxidation of organics in the gas phase lowers the volatility of semi-volatile compounds and contributes to the particulate matter by gas/particle partitioning. Heterogeneous chemistry and changes in the ambient relative humidity influence the aerosol composition as well. Molecular interactions between condensed phase species show typically non-ideal thermodynamic behavior. Liquid-liquid phase separations into a mainly polar, aqueous and a less polar, organic phase may considerably influence the gas/particle partitioning of semi-volatile organics and inorganics (Erdakos and Pankow, 2004; Chang and Pankow, 2006). Moreover, the phases present in the aerosol particles feed back on the heterogeneous, multi-phase chemistry, influence the scattering and absorption of radiation and affect the CCN ability of the particles. Non-ideal thermodynamic behavior in mixtures is usually described by an expression for the excess Gibbs energy, enabling the calculation of activity coefficients. We use the group-contribution model AIOMFAC (Zuend et al., 2008) to calculate activity coefficients, chemical potentials and the total Gibbs energy of mixed organic-inorganic systems. This thermodynamic model was combined with a robust global optimization module to compute potential liquid-liquid (LLE) and vapor-liquid-liquid equilibria (VLLE) as a function of particle composition at room temperature. And related to that, the gas/particle partitioning of semi-volatile components. Furthermore, we compute the thermodynamic stability (spinodal limits) of single-phase solutions, which provides information on the process type and kinetics of a phase separation. References Chang, E. I. and Pankow, J. F.: Prediction of activity coefficients in liquid aerosol particles containing organic compounds, dissolved inorganic salts, and water - Part 2: Consideration of phase separation effects by an XUNIFAC model, Atmos. Environ., 40, 6422-6436, 2006. Erdakos, G. B. and Pankow, J. F.: Gas/particle partitioning of neutral and ionizing compounds to single- and multi-phase aerosol particles. 2. Phase separation in liquid particulate matter containing both polar and low-polarity organic compounds, Atmos. Environ., 38, 1005-1013, 2004. Zuend, A., Marcolli, C., Luo, B. P., and Peter, T.: A thermodynamic model of mixed organic-inorganic aerosols to predict activity coefficients, Atmos. Chem. Phys., 8, 4559-4593, 2008.

Impact of agglomeration state of nano- and submicron sized gold particles on pulmonary inflammation

PubMed Central

2010-01-01

Background Nanoparticle (NP) toxicity testing comes with many challenges. Characterization of the test substance is of crucial importance and in the case of NPs, agglomeration/aggregation state in physiological media needs to be considered. In this study, we have addressed the effect of agglomerated versus single particle suspensions of nano- and submicron sized gold on the inflammatory response in the lung. Rats were exposed to a single dose of 1.6 mg/kg body weight (bw) of spherical gold particles with geometric diameters of 50 nm or 250 nm diluted either by ultrapure water or by adding phosphate buffered saline (PBS). A single dose of 1.6 mg/kg bw DQ12 quartz was used as a positive control for pulmonary inflammation. Extensive characterization of the particle suspensions has been performed by determining the zetapotential, pH, gold concentration and particle size distribution. Primary particle size and particle purity has been verified using transmission electron microscopy (TEM) techniques. Pulmonary inflammation (total cell number, differential cell count and pro-inflammatory cytokines), cell damage (total protein and albumin) and cytotoxicity (alkaline phosphatase and lactate dehydrogenase) were determined in bronchoalveolar lavage fluid (BALF) and acute systemic effects in blood (total cell number, differential cell counts, fibrinogen and C-reactive protein) 3 and 24 hours post exposure. Uptake of gold particles in alveolar macrophages has been determined by TEM. Results Particles diluted in ultrapure water are well dispersed, while agglomerates are formed when diluting in PBS. The particle size of the 50 nm particles was confirmed, while the 250 nm particles appear to be 200 nm using tracking analysis and 210 nm using TEM. No major differences in pulmonary and systemic toxicity markers were observed after instillation of agglomerated versus single gold particles of different sizes. Both agglomerated as well as single nanoparticles were taken up by macrophages. Conclusion Primary particle size, gold concentration and particle purity are important features to check, since these characteristics may deviate from the manufacturer's description. Suspensions of well dispersed 50 nm and 250 nm particles as well as their agglomerates produced very mild pulmonary inflammation at the same mass based dose. We conclude that single 50 nm gold particles do not pose a greater acute hazard than their agglomerates or slightly larger gold particles when using pulmonary inflammation as a marker for toxicity. PMID:21126342

Nanotip analysis for dielectrophoretic concentration of nanosized viral particles.

PubMed

Yeo, Woon-Hong; Lee, Hyun-Boo; Kim, Jong-Hoon; Lee, Kyong-Hoon; Chung, Jae-Hyun

2013-05-10

Rapid and sensitive detection of low-abundance viral particles is strongly demanded in health care, environmental control, military defense, and homeland security. Current detection methods, however, lack either assay speed or sensitivity, mainly due to the nanosized viral particles. In this paper, we compare a dendritic, multi-terminal nanotip ('dendritic nanotip') with a single terminal nanotip ('single nanotip') for dielectrophoretic (DEP) concentration of viral particles. The numerical computation studies the concentration efficiency of viral particles ranging from 25 to 100 nm in radius for both nanotips. With DEP and Brownian motion considered, when the particle radius decreases by two times, the concentration time for both nanotips increases by 4-5 times. In the computational study, a dendritic nanotip shows about 1.5 times faster concentration than a single nanotip for the viral particles because the dendritic structure increases the DEP-effective area to overcome the Brownian motion. For the qualitative support of the numerical results, the comparison experiment of a dendritic nanotip and a single nanotip is conducted. Under 1 min of concentration time, a dendritic nanotip shows a higher sensitivity than a single nanotip. When the concentration time is 5 min, the sensitivity of a dendritic nanotip for T7 phage is 10(4) particles ml(-1). The dendritic nanotip-based concentrator has the potential for rapid identification of viral particles.

Nanotip analysis for dielectrophoretic concentration of nanosized viral particles

NASA Astrophysics Data System (ADS)

Yeo, Woon-Hong; Lee, Hyun-Boo; Kim, Jong-Hoon; Lee, Kyong-Hoon; Chung, Jae-Hyun

2013-05-01

Rapid and sensitive detection of low-abundance viral particles is strongly demanded in health care, environmental control, military defense, and homeland security. Current detection methods, however, lack either assay speed or sensitivity, mainly due to the nanosized viral particles. In this paper, we compare a dendritic, multi-terminal nanotip (‘dendritic nanotip’) with a single terminal nanotip (‘single nanotip’) for dielectrophoretic (DEP) concentration of viral particles. The numerical computation studies the concentration efficiency of viral particles ranging from 25 to 100 nm in radius for both nanotips. With DEP and Brownian motion considered, when the particle radius decreases by two times, the concentration time for both nanotips increases by 4-5 times. In the computational study, a dendritic nanotip shows about 1.5 times faster concentration than a single nanotip for the viral particles because the dendritic structure increases the DEP-effective area to overcome the Brownian motion. For the qualitative support of the numerical results, the comparison experiment of a dendritic nanotip and a single nanotip is conducted. Under 1 min of concentration time, a dendritic nanotip shows a higher sensitivity than a single nanotip. When the concentration time is 5 min, the sensitivity of a dendritic nanotip for T7 phage is 104 particles ml-1. The dendritic nanotip-based concentrator has the potential for rapid identification of viral particles.

Mixed Calcium Dust and Carbonaceous Particles from Asia Contributing to Precipitation Changes in California

NASA Astrophysics Data System (ADS)

Kristensen, L.; Cornwell, G.; Sedlacek, A. J., III; Prather, K. A.

2016-12-01

Mineral dust particles can serve as cloud condensation nuclei (CCN), with enhanced CCN activity observed when the dust is mixed with additional soluble species. Long range atmospheric transport can change the composition of dust particles through aging, cloud processing and mixing with other particles. The CalWater2 campaign measured single particles and cloud dynamics to investigate the influence aerosols have on the hydrological cycle in California. An Aircraft Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) was used to characterize and identify single particles within clouds potentially acting as ice and cloud nuclei. Two matching flights over California's mountains in March 2015 detected significantly different particle types that resulted in different precipitation totals. Calcium dust dominated the particle composition during the first flight which had an observed decrease in orographic precipitation. Particle composition and air mass back trajectories indicate an Asian desert origin. The calcium dust particles contained secondary acids, in particular oxalic acid, acquired during transport from Asia to California. This chemical processing likely increased the solubility of the dust, enabling the particles to act as more effective CCN. The chemical composition also showed oligomeric carbonaceous species were mixed with the calcium dust particles, potentially further increasing the solubility the particles. A single particle soot photometer (SP2) measured black carbon concurrently and returned intense incandescence when calcium dust was present, confirming the calcium dust particles were internally mixed with a carbonaceous species. Dust particles were greatly reduced during the second flight with local biomass burning particles the dominant type. Observed precipitation in California were within forecast levels during the second flight. These single particle measurements from CalWater2 show that dust particles from Asia can affect cloud process and thus precipitation in California.

Automated data collection in single particle electron microscopy

PubMed Central

Tan, Yong Zi; Cheng, Anchi; Potter, Clinton S.; Carragher, Bridget

2016-01-01

Automated data collection is an integral part of modern workflows in single particle electron microscopy (EM) research. This review surveys the software packages available for automated single particle EM data collection. The degree of automation at each stage of data collection is evaluated, and the capabilities of the software packages are described. Finally, future trends in automation are discussed. PMID:26671944

Microprocessor-based single particle calibration of scintillation counter

NASA Technical Reports Server (NTRS)

Mazumdar, G. K. D.; Pathak, K. M.

1985-01-01

A microprocessor-base set-up is fabricated and tested for the single particle calibration of the plastic scintillator. The single particle response of the scintillator is digitized by an A/D converter, and a 8085 A based microprocessor stores the pulse heights. The digitized information is printed. Facilities for CRT display and cassette storing and recalling are also made available.

Single-Particle Mobility Edge in a One-Dimensional Quasiperiodic Optical Lattice

NASA Astrophysics Data System (ADS)

Lüschen, Henrik P.; Scherg, Sebastian; Kohlert, Thomas; Schreiber, Michael; Bordia, Pranjal; Li, Xiao; Das Sarma, S.; Bloch, Immanuel

2018-04-01

A single-particle mobility edge (SPME) marks a critical energy separating extended from localized states in a quantum system. In one-dimensional systems with uncorrelated disorder, a SPME cannot exist, since all single-particle states localize for arbitrarily weak disorder strengths. However, in a quasiperiodic system, the localization transition can occur at a finite detuning strength and SPMEs become possible. In this Letter, we find experimental evidence for the existence of such a SPME in a one-dimensional quasiperiodic optical lattice. Specifically, we find a regime where extended and localized single-particle states coexist, in good agreement with theoretical simulations, which predict a SPME in this regime.

Preliminary results from DIMES: Dispersion in the ACC

NASA Astrophysics Data System (ADS)

Balwada, D.; Speer, K.; LaCasce, J. H.; Owens, B.

2012-04-01

The Diapycnal and Isopynal Mixing Experiment in the Southern Ocean (DIMES) is a CLIVAR process study designed to study mixing in the Antarctic Circumpolar Current. The experiment includes tracer release, float, and small-scale turbulence components. This presentation will report on some results of the float component, from floats deployed across the ACC in the Southeast Pacific Ocean. These are the first subsurface Lagrangian trajectories from the ACC. Floats were deployed to follow approximately a constant density surface for a period of 1-3 years. To help aid the experimental results virtual floats were advected using AVISO data and basic statistics were derived from both deployed and virtual float trajectories. Experimental design, initial results, comparison to virtual floats and single particle and relative dispersion calculations will be presented.

Colloidal assembly directed by virtual magnetic moulds

NASA Astrophysics Data System (ADS)

Demirörs, Ahmet F.; Pillai, Pramod P.; Kowalczyk, Bartlomiej; Grzybowski, Bartosz A.

2013-11-01

Interest in assemblies of colloidal particles has long been motivated by their applications in photonics, electronics, sensors and microlenses. Existing assembly schemes can position colloids of one type relatively flexibly into a range of desired structures, but it remains challenging to produce multicomponent lattices, clusters with precisely controlled symmetries and three-dimensional assemblies. A few schemes can efficiently produce complex colloidal structures, but they require system-specific procedures. Here we show that magnetic field microgradients established in a paramagnetic fluid can serve as `virtual moulds' to act as templates for the assembly of large numbers (~108) of both non-magnetic and magnetic colloidal particles with micrometre precision and typical yields of 80 to 90 per cent. We illustrate the versatility of this approach by producing single-component and multicomponent colloidal arrays, complex three-dimensional structures and a variety of colloidal molecules from polymeric particles, silica particles and live bacteria and by showing that all of these structures can be made permanent. In addition, although our magnetic moulds currently resemble optical traps in that they are limited to the manipulation of micrometre-sized objects, they are massively parallel and can manipulate non-magnetic and magnetic objects simultaneously in two and three dimensions.

Double-slit experiment with single wave-driven particles and its relation to quantum mechanics.

PubMed

Andersen, Anders; Madsen, Jacob; Reichelt, Christian; Rosenlund Ahl, Sonja; Lautrup, Benny; Ellegaard, Clive; Levinsen, Mogens T; Bohr, Tomas

2015-07-01

In a thought-provoking paper, Couder and Fort [Phys. Rev. Lett. 97, 154101 (2006)] describe a version of the famous double-slit experiment performed with droplets bouncing on a vertically vibrated fluid surface. In the experiment, an interference pattern in the single-particle statistics is found even though it is possible to determine unambiguously which slit the walking droplet passes. Here we argue, however, that the single-particle statistics in such an experiment will be fundamentally different from the single-particle statistics of quantum mechanics. Quantum mechanical interference takes place between different classical paths with precise amplitude and phase relations. In the double-slit experiment with walking droplets, these relations are lost since one of the paths is singled out by the droplet. To support our conclusions, we have carried out our own double-slit experiment, and our results, in particular the long and variable slit passage times of the droplets, cast strong doubt on the feasibility of the interference claimed by Couder and Fort. To understand theoretically the limitations of wave-driven particle systems as analogs to quantum mechanics, we introduce a Schrödinger equation with a source term originating from a localized particle that generates a wave while being simultaneously guided by it. We show that the ensuing particle-wave dynamics can capture some characteristics of quantum mechanics such as orbital quantization. However, the particle-wave dynamics can not reproduce quantum mechanics in general, and we show that the single-particle statistics for our model in a double-slit experiment with an additional splitter plate differs qualitatively from that of quantum mechanics.

Asymmetric Bidirectional Controlled Quantum Information Transmission via Seven-Particle Entangled State

NASA Astrophysics Data System (ADS)

Sang, Ming-huang; Nie, Li-ping

2017-11-01

We demonstrate that a seven-particle entangled state can be used to realize the deterministic asymmetric bidirectional controlled quantum information transmission by performing only Bell-state measurement and two-particle projective measurement and single-particle measurement. In our protocol, Alice can teleport an arbitrary unknown single-particle state to Bob and at the same time Bob can remotely prepare an arbitrary known two-particle state for Alice via the control of the supervisor Charlie.

Active Brownian particles escaping a channel in single file.

PubMed

Locatelli, Emanuele; Baldovin, Fulvio; Orlandini, Enzo; Pierno, Matteo

2015-02-01

Active particles may happen to be confined in channels so narrow that they cannot overtake each other (single-file conditions). This interesting situation reveals nontrivial physical features as a consequence of the strong interparticle correlations developed in collective rearrangements. We consider a minimal two-dimensional model for active Brownian particles with the aim of studying the modifications introduced by activity with respect to the classical (passive) single-file picture. Depending on whether their motion is dominated by translational or rotational diffusion, we find that active Brownian particles in single file may arrange into clusters that are continuously merging and splitting (active clusters) or merely reproduce passive-motion paradigms, respectively. We show that activity conveys to self-propelled particles a strategic advantage for trespassing narrow channels against external biases (e.g., the gravitational field).

Active Brownian particles escaping a channel in single file

NASA Astrophysics Data System (ADS)

Locatelli, Emanuele; Baldovin, Fulvio; Orlandini, Enzo; Pierno, Matteo

2015-02-01

Active particles may happen to be confined in channels so narrow that they cannot overtake each other (single-file conditions). This interesting situation reveals nontrivial physical features as a consequence of the strong interparticle correlations developed in collective rearrangements. We consider a minimal two-dimensional model for active Brownian particles with the aim of studying the modifications introduced by activity with respect to the classical (passive) single-file picture. Depending on whether their motion is dominated by translational or rotational diffusion, we find that active Brownian particles in single file may arrange into clusters that are continuously merging and splitting (active clusters) or merely reproduce passive-motion paradigms, respectively. We show that activity conveys to self-propelled particles a strategic advantage for trespassing narrow channels against external biases (e.g., the gravitational field).

[Preparation of panax notoginseng saponins-tanshinone H(A) composite method for pulmonary delivery with spray-drying method and its characterization].

PubMed

Wang, Hua-Mei; Fu, Ting-Ming; Guo, Li-Wei

2013-02-01

To prepare panax notoginseng saponins-tanshinone II(A) composite particles for pulmonary delivery, in order to explore a dry powder particle preparation method ensuring synchronized arrival of multiple components of traditional Chinese medicine compounds at absorption sites. Panax notoginseng saponins-tanshinone II(A) composite particles were prepared with spray-drying method, and characterized by scanning electron microscopy (SEM), confocal laser scanning microscope (CLSM), X-ray diffraction (XRD), infrared analysis (IR), dry laser particle size analysis, high performance liquid chromatography (HPLC) and the aerodynamic behavior was evaluated by a Next Generation Impactor (NGI). The dry powder particles produced had narrow particle size distribution range and good aerodynamic behavior, and could realize synchronized administration of multiple components. The spray-drying method is used to combine traditional Chinese medicine components with different physical and chemical properties in the same particle, and product into traditional Chinese medicine compound particles in line with the requirements for pulmonary delivery.

Adjustable vector Airy light-sheet single optical tweezers: negative radiation forces on a subwavelength spheroid and spin torque reversal

NASA Astrophysics Data System (ADS)

Mitri, Farid G.

2018-01-01

Generalized solutions of vector Airy light-sheets, adjustable per their derivative order m, are introduced stemming from the Lorenz gauge condition and Maxwell's equations using the angular spectrum decomposition method. The Cartesian components of the incident radiated electric, magnetic and time-averaged Poynting vector fields in free space (excluding evanescent waves) are determined and computed with particular emphasis on the derivative order of the Airy light-sheet and the polarization on the magnetic vector potential forming the beam. Negative transverse time-averaged Poynting vector components can arise, while the longitudinal counterparts are always positive. Moreover, the analysis is extended to compute the optical radiation force and spin torque vector components on a lossless dielectric prolate subwavelength spheroid in the framework of the electric dipole approximation. The results show that negative forces and spin torques sign reversal arise depending on the derivative order of the beam, the polarization of the magnetic vector potential, and the orientation of the subwavelength prolate spheroid in space. The spin torque sign reversal suggests that counter-clockwise or clockwise rotations around the center of mass of the subwavelength spheroid can occur. The results find useful applications in single Airy light-sheet tweezers, particle manipulation, handling, and rotation applications to name a few examples.

POD analysis of the instability mode of a low-speed streak in a laminar boundary layer

NASA Astrophysics Data System (ADS)

Deng, Si-Chao; Pan, Chong; Wang, Jin-Jun; Rinoshika, Akira

2017-12-01

The instability of one single low-speed streak in a zero-pressure-gradient laminar boundary layer is investigated experimentally via both hydrogen bubble visualization and planar particle image velocimetry (PIV) measurement. A single low-speed streak is generated and destabilized by the wake of an interference wire positioned normal to the wall and in the upstream. The downstream development of the streak includes secondary instability and self-reproduction process, which leads to the generation of two additional streaks appearing on either side of the primary one. A proper orthogonal decomposition (POD) analysis of PIV measured velocity field is used to identify the components of the streak instability in the POD mode space: for a sinuous/varicose type of POD mode, its basis functions present anti-symmetric/symmetric distributions about the streak centerline in the streamwise component, and the symmetry condition reverses in the spanwise component. It is further shown that sinuous mode dominates the turbulent kinematic energy (TKE) through the whole streak evolution process, the TKE content first increases along the streamwise direction to a saturation value and then decays slowly. In contrast, varicose mode exhibits a sustained growth of the TKE content, suggesting an increasing competition of varicose instability against sinuous instability.

Speciation of individual mineral particles of micrometer size by the combined use of attenuated total reflectance-Fourier transform-infrared imaging and quantitative energy-dispersive electron probe X-ray microanalysis techniques.

PubMed

Jung, Hae-Jin; Malek, Md Abdul; Ryu, JiYeon; Kim, BoWha; Song, Young-Chul; Kim, HyeKyeong; Ro, Chul-Un

2010-07-15

Our previous work demonstrated for the first time the potential of the combined use of two techniques, attenuated total reflectance FT-IR (ATR-FT-IR) imaging and a quantitative energy-dispersive electron probe X-ray microanalysis, low-Z particle EPMA, for the characterization of individual aerosol particles. In this work, the speciation of mineral particles was performed on a single particle level for 24 mineral samples, including kaolinite, montmorillonite, vermiculite, talc, quartz, feldspar, calcite, gypsum, and apatite, by the combined use of ATR-FT-IR imaging and low-Z particle EPMA techniques. These two single particle analytical techniques provide complementary information, the ATR-FT-IR imaging on mineral types and low-Z particle EPMA on the morphology and elemental concentrations, on the same individual particles. This work demonstrates that the combined use of the two single particle analytical techniques can powerfully characterize externally heterogeneous mineral particle samples in detail and has great potential for the characterization of airborne mineral dust particles.

Method and apparatus for cutting and abrading with sublimable particles

DOEpatents

Bingham, D.N.

1995-10-10

A gas delivery system provides a first gas as a liquid under extreme pressure and as a gas under intermediate pressure. Another gas delivery system provides a second gas under moderate pressure. The second gas is selected to solidify at a temperature at or above the temperature of the liquefied gas. A nozzle assembly connected to the gas delivery systems produces a stream containing a liquid component, a solid component, and a gas component. The liquid component of the stream consists of a high velocity jet of the liquefied first gas. The high velocity jet is surrounded by a particle sheath that consists of solid particles of the second gas which solidifies in the nozzle upon contact with the liquefied gas of the high velocity jet. The gas component of the stream is a high velocity flow of the first gas that encircles the particle sheath, forming an outer jacket. 6 figs.

Method and apparatus for cutting and abrading with sublimable particles

DOEpatents

Bingham, Dennis N.

1995-01-01

A gas delivery system provides a first gas as a liquid under extreme pressure and as a gas under intermediate pressure. Another gas delivery system provides a second gas under moderate pressure. The second gas is selected to solidify at a temperature at or above the temperature of the liquified gas. A nozzle assembly connected to the gas delivery systems produces a stream containing a liquid component, a solid component, and a gas component. The liquid component of the stream consists of a high velocity jet of the liquified first gas. The high velocity jet is surrounded by a particle sheath that consists of solid particles of the second gas which solidifies in the nozzle upon contact with the liquified gas of the high velocity jet. The gas component of the stream is a high velocity flow of the first gas that encircles the particle sheath, forming an outer jacket.

The theory of nonstationary thermophoresis of a solid spherical particle

NASA Astrophysics Data System (ADS)

Kuzmin, M. K.; Yalamov, Yu. I.

2007-06-01

The theory of nonstationary thermophoresis of a solid spherical particle in a viscous gaseous medium is presented. The theory is constructed on the solutions of fluid-dynamics and thermal problems, each of which is split into stationary and strictly nonstationary parts. The solution of the stationary parts of the problems gives the final formula for determining the stationary component of the thermophoretic velocity of this particle. To determine the nonstationary component of the thermophoretic velocity of the particle, the corresponding formula in the space of Laplace transforms is derived. The limiting value theorems from operational calculus are used for obtaining the dependence of the nonstationary component of the thermophoretic velocity of the spherical particle on the strictly nonstationary temperature gradient for large and small values of time. The factors determining the thermophoretic velocity of the particle under investigation are determined.

A new approach to the linear theory of single-species tearing in two-dimensional quasi-neutral sheets

NASA Technical Reports Server (NTRS)

Brittnacher, M.; Quest, K. B.; Karimabadi, H.

1995-01-01

We have developed the linear theory of collisionless ion tearing in a two-dimensional magnetotail equilibrium for a single resonant species. We have solved the normal mode problem for tearing instability by an algorithm that employs particle-in-cell simulation to calculate the orbit integrals in the Maxwell-Vlasov eigenmode equation. The results of our single-species tearing analysis can be applied to ion tearing where electron effects are not included. We have calculated the tearing growth rate as a function of the magnetic field component B(sub n) normal to the current sheet for thick and thin current sheets, and we show that marginal stability occurs when the normal gyrofrequency Omega(sub n) is comparable to the Harris neutral sheet growth rate. A cross-tail B(sub y) component has little effect on the growth rate for B(sub y) approximately = B(sub n). Even in the limit B(sub y) much greater than B(sub n), the mode is strongly stabilized by B(sub n). We report than random pitch angle scattering can overcome the stabilizing effect of B(sub n) and drive the growth rate up toward the Harris neutral sheet (B(sub n) = 0) value when the pitch angle diffusion rate is comparable to Omega(sub n).

Plenoptic particle image velocimetry with multiple plenoptic cameras

NASA Astrophysics Data System (ADS)

Fahringer, Timothy W.; Thurow, Brian S.

2018-07-01

Plenoptic particle image velocimetry was recently introduced as a viable three-dimensional, three-component velocimetry technique based on light field cameras. One of the main benefits of this technique is its single camera configuration allowing the technique to be applied in facilities with limited optical access. The main drawback of this configuration is decreased accuracy in the out-of-plane dimension. This work presents a solution with the addition of a second plenoptic camera in a stereo-like configuration. A framework for reconstructing volumes with multiple plenoptic cameras including the volumetric calibration and reconstruction algorithms, including: integral refocusing, filtered refocusing, multiplicative refocusing, and MART are presented. It is shown that the addition of a second camera improves the reconstruction quality and removes the ‘cigar’-like elongation associated with the single camera system. In addition, it is found that adding a third camera provides minimal improvement. Further metrics of the reconstruction quality are quantified in terms of a reconstruction algorithm, particle density, number of cameras, camera separation angle, voxel size, and the effect of common image noise sources. In addition, a synthetic Gaussian ring vortex is used to compare the accuracy of the single and two camera configurations. It was determined that the addition of a second camera reduces the RMSE velocity error from 1.0 to 0.1 voxels in depth and 0.2 to 0.1 voxels in the lateral spatial directions. Finally, the technique is applied experimentally on a ring vortex and comparisons are drawn from the four presented reconstruction algorithms, where it was found that MART and multiplicative refocusing produced the cleanest vortex structure and had the least shot-to-shot variability. Filtered refocusing is able to produce the desired structure, albeit with more noise and variability, while integral refocusing struggled to produce a coherent vortex ring.

Aerosol hygroscopic growth parameterization based on a solute specific coefficient

NASA Astrophysics Data System (ADS)

Metzger, S.; Steil, B.; Xu, L.; Penner, J. E.; Lelieveld, J.

2011-09-01

Water is a main component of atmospheric aerosols and its amount depends on the particle chemical composition. We introduce a new parameterization for the aerosol hygroscopic growth factor (HGF), based on an empirical relation between water activity (aw) and solute molality (μs) through a single solute specific coefficient νi. Three main advantages are: (1) wide applicability, (2) simplicity and (3) analytical nature. (1) Our approach considers the Kelvin effect and covers ideal solutions at large relative humidity (RH), including CCN activation, as well as concentrated solutions with high ionic strength at low RH such as the relative humidity of deliquescence (RHD). (2) A single νi coefficient suffices to parameterize the HGF for a wide range of particle sizes, from nanometer nucleation mode to micrometer coarse mode particles. (3) In contrast to previous methods, our analytical aw parameterization depends not only on a linear correction factor for the solute molality, instead νi also appears in the exponent in form x · ax. According to our findings, νi can be assumed constant for the entire aw range (0-1). Thus, the νi based method is computationally efficient. In this work we focus on single solute solutions, where νi is pre-determined with the bisection method from our analytical equations using RHD measurements and the saturation molality μssat. The computed aerosol HGF and supersaturation (Köhler-theory) compare well with the results of the thermodynamic reference model E-AIM for the key compounds NaCl and (NH4)2SO4 relevant for CCN modeling and calibration studies. The equations introduced here provide the basis of our revised gas-liquid-solid partitioning model, i.e. version 4 of the EQuilibrium Simplified Aerosol Model (EQSAM4), described in a companion paper.

Histidinoalanine, a naturally occurring cross-link derived from phosphoserine and histidine residues in mineral-binding phosphoproteins.

PubMed

Marsh, M E

1986-05-06

Native mineral-containing phosphoprotein particles were isolated from the Heterodont bivalve Macrocallista nimbosa. The native particles are discrete structures about 40 nm in diameter which migrate as a single band during electrophoresis in agarose gels. Removal of the mineral component with ethylenediaminetetraacetic acid dissociates the native protein into nonidentical subunits. The lower molecular weight subunits, representing 8% of the total protein, were obtained by differential centrifugation. The native protein is characterized by a high content of aspartic acid, phosphoserine, phosphothreonine, histidine, and the bifunctional cross-linking residue histidinoalanine. The low molecular weight subunits have the same amino acid composition except for a reduction in histidinoalanine and a corresponding increase in phosphoserine and histidine residues, demonstrating that the alanine portion of the cross-link is derived from phosphoserine residues. Ion-exchange chromatography and molecular sieve chromatography show that the low molecular weight subunits have a similar charge density but differ in molecular weight, and the relative mobilities of the subunits on agarose gels indicate that they are polymers of a single phosphoprotein molecule. The minimum molecular weight of the monomer is about 140 000 on the basis of the amino acid composition. The high molecular weight subunits are rich in histidinoalanine and too large to be resolved by either molecular sieve chromatography or gel electrophoresis. On the basis of the ultrastructural, electrophoretic, chromatographic, and compositional evidence, native phosphoprotein particles are composed of subunits ionically cross-linked via divalent cations. These subunits are variable molecular weight aggregates of a single phosphoprotein molecule covalently cross-linked via histidinoalanine residues. Evidence for a nonenzymatic cross-linking mechanism is discussed.

On the calibration of a single channel cosmic ray particle detector

NASA Astrophysics Data System (ADS)

Maghrabi, A. H.; Alghamdi, A. S.; Alotaibi, R.; Almutari, M. M.; Garawi, M. S.

2014-07-01

Cosmic Ray (CR) variation measurements have been extensively conducted using different type of detectors sensing different components of CR and at different locations around the world. We have constructed and, operated a single channel muon detector in the central part of Saudi Arabia. The main goal of this detector is to record the intensity of cosmic rays on different time scales and investigate their correlations with environment parameters. This detector is expected to fill the gap between neutron monitors and muon telescopes that exist around the world. In this paper, the technical aspects of this detector will be briefly discussed. Calibration procedures conducted to characterize and improve its performance will be detailed. These include the effect of the detector geometry and the internal surface coating.

Relation between aerosol sources and meteorological parameters for inhalable atmospheric particles in Sao Paulo City, Brazil

NASA Astrophysics Data System (ADS)

Andrade, Fatima; Orsini, Celso; Maenhaut, Willy

Stacked filter units were used to collect atmospheric particles in separate coarse and fine fractions at the Sao Paulo University Campus during the winter of 1989. The samples were analysed by particle-induced X-ray emission (PIXE) and the data were subjected to an absolute principal component analysis (APCA). Five sources were identified for the fine particles: industrial emissions, which accounted for 13% of the fine mass; emissions from residual oil and diesel, explaining 41%; resuspended soil dust, with 28%; and emissions of Cu and of Mg, together with 18%. For the coarse particles, four sources were identified: soil dust, accounting for 59% of the coarse mass; industrial emissions, with 19%; oil burning, with 8%; and sea salt aerosol, with 14% of the coarse mass. A data set with various meteorological parameters was also subjected to APCA, and a correlation analysis was performed between the meteorological "absolute principal component scores" (APCS) and the APCS from the fine and coarse particle data sets. The soil dust sources for the fine and coarse aerosol were highly correlated with each other and were anticorrelated with the sea breeze component. The industrial components in the fine and coarse size fractions were also highly positively correlated. Furthermore, the industrial component was related with the northeasterly wind direction and, to a lesser extent, with the sea breeze component.

Methods of forming semiconductor devices and devices formed using such methods

DOEpatents

Fox, Robert V; Rodriguez, Rene G; Pak, Joshua

2013-05-21

Single source precursors are subjected to carbon dioxide to form particles of material. The carbon dioxide may be in a supercritical state. Single source precursors also may be subjected to supercritical fluids other than supercritical carbon dioxide to form particles of material. The methods may be used to form nanoparticles. In some embodiments, the methods are used to form chalcopyrite materials. Devices such as, for example, semiconductor devices may be fabricated that include such particles. Methods of forming semiconductor devices include subjecting single source precursors to carbon dioxide to form particles of semiconductor material, and establishing electrical contact between the particles and an electrode.

Development of a single-axis ultrasonic levitator and the study of the radial particle oscillations

NASA Astrophysics Data System (ADS)

Baer, Sebastian; Andrade, Marco A. B.; Esen, Cemal; Adamowski, Julio Cezar; Ostendorf, Andreas

2012-05-01

This work describes the development and analysis of a new single-axis acoustic levitator, which consists of a 38 kHz Langevin-type piezoelectric transducer with a concave radiating surface and a concave reflector. The new levitator design allows to significantly reducing the electric power necessary to levitate particles and to stabilize the levitated sample in both radial and axial directions. In this investigation the lateral oscillations of a levitated particle were measured with a single point Laser Doppler Vibrometer (LDV) and an image evaluation technique. The lateral oscillations were measured for different values of particle diameter, particle density and applied electrical power.

Tracking single particle rotation: Probing dynamics in four dimensions

DOE PAGES

Anthony, Stephen Michael; Yu, Yan

2015-04-29

Direct visualization and tracking of small particles at high spatial and temporal resolution provides a powerful approach to probing complex dynamics and interactions in chemical and biological processes. Analysis of the rotational dynamics of particles adds a new dimension of information that is otherwise impossible to obtain with conventional 3-D particle tracking. In this review, we survey recent advances in single-particle rotational tracking, with highlights on the rotational tracking of optically anisotropic Janus particles. Furthermore, strengths and weaknesses of the various particle tracking methods, and their applications are discussed.

Structure and Dynamics of Bimodal Colloidal Dispersions in a Low-Molecular-Weight Polymer Solution

DOE PAGES

Zhang, Fan; Allen, Andrew J.; Levine, Lyle E.; ...

2017-02-24

We present an experimental study of the structural and dynamical properties of bimodal, micrometersized colloidal dispersions (size ratio ≈ 2) in an aqueous solution of low-molecular weight polymer (polyethylene glycol 2000) using synchrotron ultra-small angle X-ray scattering (USAXS) and USAXSbased X-ray photon correlation spectroscopy. We fixed the volume fraction of the large particles at 5 % and systematically increased the volume fraction of the small particles from 0 % to 5 % to evaluate its effect on the structure and dynamics. The bimodal dispersions were homogenous through the investigated parameter space. We found that the partial structure factors can bemore » satisfactorily retrieved for the bimodal colloidal dispersions using a Percus-Yevick hard sphere potential when the particle size distributions of the particles were taken into account. We also found that the partial structure factor between the large particles does not exhibit significant variation with increasing volume fraction of small particles, whereas the isothermal compressibility of the binary mixture was found to decrease with increasing volume fraction of small particles. The dynamics of single-component large particle dispersion obey the principles of de Gennes narrowing, where the wave vector dependence of the interparticle diffusion coefficient is inversely proportional to the interparticle structure factor. The dynamics of the bimodal dispersions demonstrate strong dependence on the fraction of small particles. As a result, we also made a comparison between the experimental effective dynamic viscosity of the bimodal dispersion with theoretical predictions, which suggest that the complex mutual interactions between large and small particles have a strong effect on the dynamic behaviors of bimodal dispersions.« less

Structure and Dynamics of Bimodal Colloidal Dispersions in a Low-Molecular-Weight Polymer Solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Fan; Allen, Andrew J.; Levine, Lyle E.

We present an experimental study of the structural and dynamical properties of bimodal, micrometersized colloidal dispersions (size ratio ≈ 2) in an aqueous solution of low-molecular weight polymer (polyethylene glycol 2000) using synchrotron ultra-small angle X-ray scattering (USAXS) and USAXSbased X-ray photon correlation spectroscopy. We fixed the volume fraction of the large particles at 5 % and systematically increased the volume fraction of the small particles from 0 % to 5 % to evaluate its effect on the structure and dynamics. The bimodal dispersions were homogenous through the investigated parameter space. We found that the partial structure factors can bemore » satisfactorily retrieved for the bimodal colloidal dispersions using a Percus-Yevick hard sphere potential when the particle size distributions of the particles were taken into account. We also found that the partial structure factor between the large particles does not exhibit significant variation with increasing volume fraction of small particles, whereas the isothermal compressibility of the binary mixture was found to decrease with increasing volume fraction of small particles. The dynamics of single-component large particle dispersion obey the principles of de Gennes narrowing, where the wave vector dependence of the interparticle diffusion coefficient is inversely proportional to the interparticle structure factor. The dynamics of the bimodal dispersions demonstrate strong dependence on the fraction of small particles. As a result, we also made a comparison between the experimental effective dynamic viscosity of the bimodal dispersion with theoretical predictions, which suggest that the complex mutual interactions between large and small particles have a strong effect on the dynamic behaviors of bimodal dispersions.« less

Micrometer-scale particle sizing by laser diffraction: critical impact of the imaginary component of refractive index.

PubMed

Beekman, Alice; Shan, Daxian; Ali, Alana; Dai, Weiguo; Ward-Smith, Stephen; Goldenberg, Merrill

2005-04-01

This study evaluated the effect of the imaginary component of the refractive index on laser diffraction particle size data for pharmaceutical samples. Excipient particles 1-5 microm in diameter (irregular morphology) were measured by laser diffraction. Optical parameters were obtained and verified based on comparison of calculated vs. actual particle volume fraction. Inappropriate imaginary components of the refractive index can lead to inaccurate results, including false peaks in the size distribution. For laser diffraction measurements, obtaining appropriate or "effective" imaginary components of the refractive index was not always straightforward. When the recommended criteria such as the concentration match and the fit of the scattering data gave similar results for very different calculated size distributions, a supplemental technique, microscopy with image analysis, was used to decide between the alternatives. Use of effective optical parameters produced a good match between laser diffraction data and microscopy/image analysis data. The imaginary component of the refractive index can have a major impact on particle size results calculated from laser diffraction data. When performed properly, laser diffraction and microscopy with image analysis can yield comparable results.

Self-assembly concepts in the formation of nanostructured particles using a liquid-phase synthesis method

NASA Astrophysics Data System (ADS)

Nandiyanto, Asep Bayu Dani

2016-02-01

When synthesizing particles using a liquid-phase synthesis method, reactant components show interaction with the reaction system itself. However, current reports described successful synthesis of material with only partial information on the component-component interaction and possible self-assembly mechanism occurring during the material synthesis process. Here, self-assembly concepts in the formation of nanostructured particles are presented. Influences of self-assembly parameters (i.e., surface charge, size, and concentration of components involving the reaction) on self-organized material fabrication are described. Because understanding the interaction of the component provides significant information in regard to practical uses, this report can be relevant to further material development and fabrication.

A Dose-Rate Effect in Single-Particle Electron Microscopy

PubMed Central

Chen, James Z.; Sachse, Carsten; Xu, Chen; Mielke, Thorsten; Spahn, Christian M. T.; Grigorieff, Nikolaus

2008-01-01

A low beam-intensity, low electron-dose imaging method has been developed for single-particle electron cryo-microscopy (cryo-EM). Experiments indicate that the new technique can reduce beam-induced specimen movement and secondary radiolytic effects, such as “bubbling”. The improvement in image quality, especially for multiple-exposure data collection, will help single-particle cryo-EM to reach higher resolution. PMID:17977018

A 6.1 s isomer and rotational bands in $sup 192$Os

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pakkanen, A.; Heikkinen, D.W.

A 6.1 plus or minus 0.2 s activity has been observed when natural Os targets were bombarded with 14.5 MeV neutrons. The activity is assigned to the decay of a high-spin isomer in /sup 192/Os at 2015.4 keV, which is depopulated by M2 and E3 transitions. Singles and coincidence gamma -ray spectra have allowed the identification of seven new states in /sup 192/Os. Several of these levels have been placed in either the ground- state or gamma -vibrational bands, which are strongly mixed. Excitation energies, B(E2) ratios for these bands are compared with different theoretical models. (auth) It is shownmore » that, if one uses single-particle energies from experiment and a delta residual interaction, it is not possible to obtain the energy of the giant dipole and spurious states of /sup 208/Pb, and at the same time obtain reasonable results for the low-lying two- particle spectra of /sup 210/Pb or /sup 210/Po. Related to the above problem, the isobaric analog state of /sup 208/Pb (in /sup 208/Bi) comes much too low in calculations using realistic interactions. It is noted that the above difficulties can be overcome, phenomenologically at least, by adding to the effective interaction some longrange repulsive components. The Bansal- French and the Schiffer interactions are examples of these; however, the dipole--dipole component of the Schiffer interaction gives much too large a splitting between the dipole state and spurious state. (auth)« less

Single-particle characterization of indoor aerosol particles collected at an underground shopping area in Seoul, Korea.

PubMed

Maskey, Shila; Kang, TaeHee; Jung, Hae-Jin; Ro, Chul-Un

2011-02-01

In this study, single-particle characterization of aerosol particles collected at an underground shopping area was performed for the first time. A quantitative single-particle analytical technique, low-Z particle electron probe X-ray microanalysis, was used to characterize a total of 7900 individual particles for eight sets of aerosol samples collected at an underground shopping area in Seoul, Korea. Based on secondary electron images and X-ray spectral data of individual particles, fourteen particle types were identified, in which primary soil-derived particles were the most abundant, followed by carbonaceous, Fe-containing, secondary soil-derived, and secondary sea-salt particles. Carbonaceous particles exist in three types: organic carbon, carbon-rich, and CNO-rich. A significant number of textile particles with chemical composition C, N, and O were encountered in some of the aerosol samples, which were from the textile shops and/or from clothes of passersby. Primary soil-derived particles showed seasonal variation, with peak values in spring samples, reflecting higher air exchange between indoor and outdoor environments in the spring. Secondary soil-derived, secondary sea-salt, and ammonium sulfate particles were frequently encountered in winter samples. Fe-containing particles, contributed from a nearby subway station, were in the range of about 19% relative abundances for all samples. In underground shopping areas, particulate matters can be a considerable health hazard to the workers, shoppers, passersby, and shop-keepers as they spend their considerable time in this closed microenvironment. However, no study on the characteristics of indoor aerosols in an underground shopping area has been reported to our knowledge. This work provides detailed information on characteristics of underground shopping area aerosols on a single particle level. © 2010 John Wiley & Sons A/S.

Magnetic Assisted Colloidal Pattern Formation

NASA Astrophysics Data System (ADS)

Yang, Ye

Pattern formation is a mysterious phenomenon occurring at all scales in nature. The beauty of the resulting structures and myriad of resulting properties occurring in naturally forming patterns have attracted great interest from scientists and engineers. One of the most convenient experimental models for studying pattern formation are colloidal particle suspensions, which can be used both to explore condensed matter phenomena and as a powerful fabrication technique for forming advanced materials. In my thesis, I have focused on the study of colloidal patterns, which can be conveniently tracked in an optical microscope yet can also be thermally equilibrated on experimentally relevant time scales, allowing for ground states and transitions between them to be studied with optical tracking algorithms. In particular, I have focused on systems that spontaneously organize due to particle-surface and particle-particle interactions, paying close attention to systems that can be dynamically adjusted with an externally applied magnetic or acoustic field. In the early stages of my doctoral studies, I developed a magnetic field manipulation technique to quantify the adhesion force between particles and surfaces. This manipulation technique is based on the magnetic dipolar interactions between colloidal particles and their "image dipoles" that appear within planar substrate. Since the particles interact with their own images, this system enables massively parallel surface force measurements (>100 measurements) in a single experiment, and allows statistical properties of particle-surface adhesion energies to be extracted as a function of loading rate. With this approach, I was able to probe sub-picoNewton surface interactions between colloidal particles and several substrates at the lowest force loading rates ever achieved. In the later stages of my doctoral studies, I focused on studying patterns formed from particle-particle interaction, which serve as an experimental model of phase transitions in condensed matter systems that can be tracked with single particle resolution. Compared with other research on colloidal crystal formation, my research has focused on multi-component colloidal systems of magnetic and non-magnetic colloids immersed in a ferrofluid. Initially, I studied the types of patterns that form as a function of the concentrations of the different particles and ferrofluid, and I discovered a wide variety of chains, rings and crystals forming in bi-component and tri-component systems. Based on these results, I narrowed my focus to one specific crystal structure (checkerboard lattice) as a model of phase transformations in alloy. Liquid/solid phase transitions were studied by slowly adjusting the magnetic field strength, which serves to control particle-particle interactions in a manner similar to controlling the physical temperature of the fluid. These studies were used to determine the optimal conditions for forming large single crystal structures, and paved the way for my later work on solid/solid phase transitions when the angle of the external field was shifted away from the normal direction. The magnetostriction coefficient of these crystals was measured in low tilt angle of the applied field. At high tilt angles, I observed a variety of martensitic transformations, which followed different pathways depending on the crystal direction relative to the in-plane field. In the last part of my doctoral studies, I investigated colloidal patterns formed in a superimposed acoustic and magnetic field. In this approach, the magnetic field mimics "temperature", while the acoustic field mimics "pressure". The ability to simultaneously tune both temperature and pressure allows for more efficient exploration of phase space. With this technique I demonstrated a large class of particle structures ranging from discrete molecule-like clusters to well ordered crystal phases. Additionally, I demonstrated a crosslinking strategy based on photoacids, which stabilized the structures after the external field was removed. This approach has potential applications in the fabrication of advanced materials. My thesis is arranged as follows. In Chapter 1, I present a brief background of general pattern formation and why I chose to investigate patterns formed in colloidal systems. I also provide a brief review of field-assisted manipulation techniques in order to motivate why I selected magnetic and acoustic field to study colloidal patterns. In chapter 2, I present the theoretical background of magnetic manipulation, which is the main technique used in my research. In this chapter, I will introduce the basic knowledge on magnetic materials and theories behind magnetic manipulation. The underlining thermodynamic mechanisms and theoretical/computational approaches in colloidal pattern formation are also briefly reviewed. In Chapter 3, I focus on using these concepts to study adhesion forces between particle and surfaces. In Chapter 4, I focus on exploring the ground states of colloidal patterns formed from the anti-ferromagnetic interactions of mixtures of particles, as a function of the particle volume fractions. In Chapter 5, I discuss my research on phase transformations of the well-ordered checkerboard phase formed from the equimolar mixture of magnetic and non-magnetic beads in ferrofluid, and I focus mainly on phase transformations in a slowly varying magnetic field. In Chapter 6, I discuss my work on the superimposed magnetic and acoustic field to study patterns formed from monocomponent colloidal suspensions under vertical confinement. Finally, I conclude my thesis in Chapter 7 and discuss future directions and open questions that can be explored in magnetic field directed self-organization in colloidal systems.

[Comparison of in vivo characteristics of polyethylene wear particles produced by a metal and a ceramic femoral component in total knee replacement].

PubMed

Veigl, D; Vavřík, P; Pokorný, D; Slouf, M; Pavlova, E; Landor, I

2011-01-01

The aim of the study was to evaluate in vivo and compare, in terms of the quality and number of ultra high-molecular polyethylene (UHMWPE) wear particles, total knee replacements of identical construction differing only in the material used for femoral component production, i.e., CoCrMo alloy or ZrO2 ceramics. Samples of peri-prosthetic granuloma tissue were collected in two patients with total knee replacement suffering from implant migration, who were matched in relevant characteristics. The primary knee replacement in Patient 1 with a CoCrMo femoral component was done 7.2 years and in Patient 2 with a ZrO2 implant 6.8 years before this assessment. The polyethylene wear-induced granuloma was analysed by the MORF method enabling us to assess the shape and size of wear debris and the IRc method for assessment of particle concentration. In the granuloma tissue samples of Patient 1, on the average, particles were 0.30 mm in size and their relative volume was 0.19. In the Patient 2 tissue samples, the average size of particles was 0.33 mm and their relative volume was 0.26. There was no significant difference in either particle morphology or their concentration in the granuloma tissue between the two patients. One of the options of how to reduce the production of polyethylene wear particles is to improve the tribological properties of contacting surfaces in total knee replacement by substituting a cobalt-chrome femoral component with a zirconia ceramic femoral component. The previous in vitro testing carried out with a mechanical simulator under conditions approaching real weight-bearing in the human body did show a nearly three-fold decrease in the number of UHMWPE wear particles in zirconia components. The evaluation of granuloma tissue induced by the activity of a real prosthetic joint for nearly seven years, however, did not reveal any great difference in either quality or quantity of polyethylene debris between the two replacements. The difference of surface roughness between CoCrMo (Ra = 0.05) and ZrO2 (Ra = 0.02) components did not play any role in in vivo conditions. CONCLUSIONS In accordance with a previous clinical study, this evaluation of the quality and quantity of UHMWPE wear particles produced by a ceramic femoral component in vivo failed to demonstrate any advantage of zirconia ceramic components over the cobalt-chrome femoral components so far used.

Single particle train ordering in microchannel based on inertial and vortex effects

NASA Astrophysics Data System (ADS)

Fan, Liang-Liang; Yan, Qing; Zhe, Jiang; Zhao, Liang

2018-06-01

A new microfluidic device for microparticle focusing and ordering in a single particle train is reported. The particle focusing and ordering are based on inertial and vortex effects in a microchannel with a series of suddenly contracted and widely expanded structures on one side. In the suddenly contracted regions, particles located near the contracted structures are subjected to a strong wall-effect lift force and momentum-change-induced inertial force due to the highly curved trajectory, migrating to the straight wall. A horizontal vortex is generated downstream of the contracted structure, which prevents the particle from getting close to the wall. In the widely expanded regions, the streamline is curved and no vortex is generated. The shear-gradient lift force and the momentum-change-induced inertial force are dominant for particle lateral migration, driving particles towards the wall of the expanded structures. Eventually, particles are focused and ordered in a single particle train by the combination effects of the inertial forces and the vortex. In comparison with other single-stream particle focusing methods, this device requires no sheath flow, is easy for fabrication and operation, and can work over a wide range of Reynolds numbers from 19.1–142.9. The highly ordered particle chain could be potentially utilized in a variety of lab-chip applications, including micro-flow cytometer, imaging and droplet-based cell entrapment.

Remarkable NO oxidation on single supported platinum atoms

DOE PAGES

Narula, Chaitanya K.; Allard, Lawrence F.; Stocks, G. M.; ...

2014-11-28

Our first-principles density functional theoretical modeling suggests that NO oxidation is feasible on fully oxidized single θ-alumina-supported platinum atoms via a modified Langmuir-Hinshelwood pathway. This is in contrast to the known decrease in NO oxidation activity of supported platinum with decreasing Pt particle size believed to be due to increased platinum oxidation. In order to validate our theoretical study, we evaluated single θ-Al 2O 3-supported platinum atoms and found them to exhibit remarkable NO oxidation activity. A comparison of turnover frequencies (TOF) of single supported Pt atoms with those of platinum particles for NO oxidation shows that single supported Ptmore » atoms are as active as fully formed platinum particles. The overall picture of NO oxidation on supported Pt is that NO oxidation activity decreases with decreasing Pt particle size but accelerates when Pt is present only as single atoms.« less

Crystalline structures of particles interacting through the harmonic-repulsive pair potential

NASA Astrophysics Data System (ADS)

Levashov, V. A.

2017-09-01

The behavior of identical particles interacting through the harmonic-repulsive pair potential has been studied in 3D using molecular dynamics simulations at a number of different densities. We found that at many densities, as the temperature of the systems decreases, the particles crystallize into complex structures whose formation has not been anticipated in previous studies on the harmonic-repulsive pair potential. In particular, at certain densities, crystallization into the structure I a 3 ¯ d (space group #230) with 16 particles in the unit cell occupying Wyckoff special positions (16b) was observed. This crystal structure has not been observed previously in experiments or in computer simulations of single component atomic or soft matter systems. At another density, we observed a liquid which is rather stable against crystallization. Yet, we observed crystallization of this liquid into the monoclinic C2/c (space group #15) structure with 32 particles in the unit cell occupying four different non-special Wyckoff (8f) sites. In this structure particles located at different Wyckoff sites have different energies. From the perspective of the local atomic environment, the organization of particles in this structure resembles the structure of some columnar quasicrystals. At a different value of the density, we did not observe crystallization at all despite rather long molecular dynamics runs. At two other densities, we observed the formation of the β S n distorted diamond structures instead of the expected diamond structure. Possibly, we also observed the formation of the R 3 ¯ c hexagonal lattice with 24 particles per unit cell occupying non-equivalent positions.

Single-shot imaging of trapped Fermi gas

NASA Astrophysics Data System (ADS)

Gajda, Mariusz; Mostowski, Jan; Sowiński, Tomasz; Załuska-Kotur, Magdalena

2016-07-01

Recently developed techniques allow for simultaneous measurements of the positions of all ultra-cold atoms in a trap with high resolution. Each such single-shot experiment detects one element of the quantum ensemble formed by the cloud of atoms. Repeated single-shot measurements can be used to determine all correlations between particle positions as opposed to standard measurements that determine particle density or two-particle correlations only. In this paper we discuss the possible outcomes of such single-shot measurements in the case of cloud of ultra-cold noninteracting Fermi atoms. We show that the Pauli exclusion principle alone leads to correlations between particle positions that originate from unexpected spatial structures formed by the atoms.

Photophoretic trapping of absorbing particles in air and measurement of their single-particle Raman spectra.

PubMed

Pan, Yong-Le; Hill, Steven C; Coleman, Mark

2012-02-27

A new method is demonstrated for optically trapping micron-sized absorbing particles in air and obtaining their single-particle Raman spectra. A 488-nm Gaussian beam from an Argon ion laser is transformed by conical lenses (axicons) and other optics into two counter-propagating hollow beams, which are then focused tightly to form hollow conical beams near the trapping region. The combination of the two coaxial conical beams, with focal points shifted relative to each other along the axis of the beams, generates a low-light-intensity biconical region totally enclosed by the high-intensity light at the surface of the bicone, which is a type of bottle beam. Particles within this region are trapped by the photophoretic forces that push particles toward the low-intensity center of this region. Raman spectra from individual trapped particles made from carbon nanotubes are measured. This trapping technique could lead to the development of an on-line real-time single-particle Raman spectrometer for characterization of absorbing aerosol particles.

Study of the phase transformation of single particles of Ga2O3 by UV-Raman spectroscopy and high-resolution TEM.

PubMed

Wang, Xiang; Xu, Qian; Fan, Fengtao; Wang, Xiuli; Li, Mingrun; Feng, Zhaochi; Li, Can

2013-09-01

By taking advantage of UV-Raman spectroscopy and high-resolution TEM (HRTEM), combined with the focused ion beam (FIB) technique, the transformation from GaOOH into α-Ga2O3 and then into β-Ga2O3 was followed. We found that the stepwise transformations took place from the surface region before developing into the bulk of single particles without particle agglomeration and growth. During the transformation from GaOOH into α-Ga2O3, the elimination of water vapor through the dehydroxylation of GaOOH resulted in the formation of micropores in the single particles, whilst maintaining their particle size. For the phase transformation from α-Ga2O3 into β-Ga2O3, the nucleation of β-Ga2O3 was found to occur at the surface defects and this process could be retarded by occupying these defects with a small amount of La2O3. By finely controlling the process of the phase transformation, the β-Ga2O3 domains gradually developed from the surface into the bulk of the single particles without particle agglomeration. Therefore, the surface structure of the α-Ga2O3 single particles can be easily tuned and a particle with an α@β core-shell phase structure has been obtained. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Role of small-norm components in extended random-phase approximation

NASA Astrophysics Data System (ADS)

Tohyama, Mitsuru

2017-09-01

The role of the small-norm amplitudes in extended random-phase approximation (RPA) theories such as the particle-particle and hole-hole components of one-body amplitudes and the two-body amplitudes other than two-particle/two-hole components are investigated for the one-dimensional Hubbard model using an extended RPA derived from the time-dependent density matrix theory. It is found that these amplitudes cannot be neglected in strongly interacting regions where the effects of ground-state correlations are significant.

The influences of ambient particle composition and size on particle infiltration in Los Angeles, CA, residences.

PubMed

Sarnat, Stefanie Ebelt; Coull, Brent A; Ruiz, Pablo A; Koutrakis, Petros; Suh, Helen H

2006-02-01

Particle infiltration is a key determinant of the indoor concentrations of ambient particles. Few studies have examined the influence of particle composition on infiltration, particularly in areas with high concentrations of volatile particles, such as ammonium nitrate (NH4NO3). A comprehensive indoor monitoring study was conducted in 17 Los Angeles-area homes. As part of this study, indoor/outdoor concentration ratios during overnight (nonindoor source) periods were used to estimate the fraction of ambient particles remaining airborne indoors, or the particle infiltration factor (FINF), for fine particles (PM2.5), its nonvolatile (i.e., black carbon [BC]) and volatile (i.e., nitrate [NO3-]) components, and particle sizes ranging between 0.02 and 10 microm. FINF was highest for BC (median = 0.84) and lowest for NO3- (median = 0.18). The low FINF for NO3- was likely because of volatilization of NO3- particles once indoors, in addition to depositional losses upon building entry. The FINF for PM2.5 (median = 0.48) fell between those for BC and NO3-, reflecting the contributions of both particle components to PM25. FINF varied with particle size, air-exchange rate, and outdoor NO3- concentrations. The FINF for particles between 0.7 and 2 microm in size was considerably lower during periods of high as compared with low outdoor NO3- concentrations, suggesting that outdoor NO3- particles were of this size. This study demonstrates that infiltration of PM2.5 varies by particle component and is lowest for volatile species, such as NH4NO3. Our results suggest that volatile particle components may influence the ability for outdoor PM concentrations to represent indoor and, thus, personal exposures to particles of ambient origin, because volatilization of these particles causes the composition of PM2.5 to differ indoors and outdoors. Consequently, particle composition likely influences observed epidemiologic relationships based on outdoor PM concentrations, especially in areas with high concentrations of NH4NO3 and other volatile particles.

On the role of adhesion in single-file dynamics

NASA Astrophysics Data System (ADS)

Fouad, Ahmed M.; Noel, John A.

2017-08-01

For a one-dimensional interacting system of Brownian particles with hard-core interactions (a single-file model), we study the effect of adhesion on both the collective diffusion (diffusion of the entire system with respect to its center of mass) and the tracer diffusion (diffusion of the individual tagged particles). For the case with no adhesion, all properties of these particle systems that are independent of particle labeling (symmetric in all particle coordinates and velocities) are identical to those of non-interacting particles (Lebowitz and Percus, 1967). We clarify this last fact twice. First, we derive our analytical predictions that show that the probability-density functions of single-file (ρsf) and ordinary (ρord) diffusion are identical, ρsf =ρord, predicting a nonanomalous (ordinary) behavior for the collective single-file diffusion, where the average second moment with respect to the center of mass, < x(t) 2 > , is calculated from ρ for both diffusion processes. Second, for single-file diffusion, we show, both analytically and through large-scale simulations, that < x(t) 2 > grows linearly with time, confirming the nonanomalous behavior. This nonanomalous collective behavior comes in contrast to the well-known anomalous sub-diffusion behavior of the individual tagged particles (Harris, 1965). We introduce adhesion to single-file dynamics as a second inter-particle interaction rule and, interestingly, we show that adding adhesion does reduce the magnitudes of both < x(t) 2 > and the mean square displacement per particle Δx2; but the diffusion behavior remains intact independent of adhesion in both cases. Moreover, we study the dependence of both the collective diffusion constant D and the tracer diffusion constant DT on the adhesion coefficient α.

A new single-particle basis for nuclear many-body calculations

NASA Astrophysics Data System (ADS)

Puddu, G.

2017-10-01

Predominantly, harmonic oscillator single-particle wave functions are the preferred choice for a basis in ab initio nuclear many-body calculations. These wave-functions, although very convenient in order to evaluate the matrix elements of the interaction in the laboratory frame, have too fast a fall-off at large distances. In the past, as an alternative to the harmonic oscillator, other single-particle wave functions have been proposed. In this work, we propose a new single-particle basis, directly linked to nucleon-nucleon interaction. This new basis is orthonormal and complete, has the proper asymptotic behavior at large distances and does not contain the continuum which would pose severe convergence problems in nuclear many body calculations. We consider the newly proposed NNLO-opt nucleon-nucleon interaction, without any renormalization. We show that, unlike other bases, this single-particle representation has a computational cost similar to the harmonic oscillator basis with the same space truncation and it gives lower energies for 6He and 6Li.

Raman Spectroscopy of Single Light-Absorbing Carbonaceous Particles Levitated in Air Using an Annular Laser Beam.

PubMed

Uraoka, Masaru; Maegawa, Keisuke; Ishizaka, Shoji

2017-12-05

A laser trapping technique is a powerful means to investigate the physical and chemical properties of single aerosol particles in a noncontact manner. However, optical trapping of strongly light-absorbing particles such as black carbon or soot is quite difficult because the repulsive force caused by heat is orders of magnitude larger than the attractive force of radiation pressure. In this study, a laser trapping and Raman microspectroscopy system using an annular laser beam was constructed to achieve noncontact levitation of single light-absorbing particles in air. Single acetylene carbon black or candle soot particles were arbitrarily selected with a glass capillary connected to a three-axis oil hydraulic micromanipulator and introduced into a minute space surrounded by a repulsive force at the focal point of an objective lens. Using the developed system, we achieved optical levitation of micrometer-sized carbonaceous particles and observation of their Raman spectra in air. Furthermore, we demonstrated in situ observations of changes in the morphology and chemical composition of optically trapped carbonaceous particles in air, which were induced by heterogeneous oxidation reactions with ozone and hydroxyl radicals.

Preparation and characterization of SiO2-coated submicron-sized L10 Fe-Pt particles

NASA Astrophysics Data System (ADS)

Hayashi, Yoshiaki; Ogawa, Tomoyuki; Ishiyama, Kazushi

2018-05-01

The development of magnets with higher performance is attracting increasing interest. The optimization of their microstructure is essential to enhance their properties, and a microstructure comprising magnetically isolated hard magnetic grains of a single-domain size has been proposed as an ideal structure for enhancing the coercivity of magnets. To obtain magnets with an ideal structure, we consider the fabrication of magnets by an approach based on core/shell nanoparticles with a hard magnetic core and a non-magnetic shell. In this study, to obtain particles for our proposed approach, we attempted to fabricate L10 Fe-Pt/SiO2-core/shell particles with submicron-sized cores less than the critical single-domain size. The fabrication of such core/shell particles was confirmed from morphology observations and XRD analysis of the particles. Although the formation of more desirable core/shell particles with submicron-sized single-crystal cores in the single-domain size range was not achieved, the fabricated core/shell particles showed a high coercivity of 25 kOe.

Planck 2013 results. X. HFI energetic particle effects: characterization, removal, and simulation

NASA Astrophysics Data System (ADS)

Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J. J.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Bridges, M.; Bucher, M.; Burigana, C.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, H. C.; Chiang, L.-Y.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Girard, D.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Hansen, F. K.; Hanson, D.; Harrison, D.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Laureijs, R. J.; Lawrence, C. R.; Leonardi, R.; Leroy, C.; Lesgourgues, J.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Mandolesi, N.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Mazzotta, P.; McGehee, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Miniussi, A.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Mottet, S.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Racine, B.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rusholme, B.; Sanselme, L.; Santos, D.; Sauvé, A.; Savini, G.; Scott, D.; Shellard, E. P. S.; Spencer, L. D.; Starck, J.-L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sureau, F.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Yvon, D.; Zacchei, A.; Zonca, A.

2014-11-01

We describe the detection, interpretation, and removal of the signal resulting from interactions of high energy particles with the Planck High Frequency Instrument (HFI). There are two types of interactions: heating of the 0.1 K bolometer plate; and glitches in each detector time stream. The transientresponses to detector glitch shapes are not simple single-pole exponential decays and fall into three families. The glitch shape for each family has been characterized empirically in flight data and these shapes have been used to remove glitches from the detector time streams. The spectrum of the count rate per unit energy is computed for each family and a correspondence is made to the location on the detector of the particle hit. Most of the detected glitches are from Galactic protons incident on the die frame supporting the micro-machined bolometric detectors. In the Planck orbit at L2, the particle flux is around 5 cm-2 s-1 and is dominated by protons incident on the spacecraft with energy >39 MeV, at a rate of typically one event per second per detector. Different categories of glitches have different signatures in the time stream. Two of the glitch types have a low amplitude component that decays over nearly 1 s. This component produces excess noise if not properly removed from the time-ordered data. We have used a glitch detection and subtraction method based on the joint fit of population templates. The application of this novel glitch subtraction method removes excess noise from the time streams. Using realistic simulations, we find that this method does not introduce signal bias into the Planck data.

Department of Defense Enhanced Particulate Matter Surveillance Program (EPMSP)

DTIC Science & Technology

2008-02-01

on Teflon® membrane, 23,807 on quartz fiber, and several million single particle analyses on Nuclepore® filters. Analytical results were...Nuclepore® filters, the sampling period was two hours, so as to provide lightly loaded filters with dispersed single particles, as required for CCSEM...membrane, 23,807 on quartz fiber, and several million single particle analyses on Nuclepore®. All results, together with summary tables and more than

Real-time Molecular Study of Bystander Effects of Low dose Low LET radiation Using Living Cell Imaging and Nanoparticale Optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Natarajan, Mohan; Xu, Nancy R; Mohan, Sumathy

2013-06-03

In this study two novel approaches are proposed to investigate precisely the low dose low LET radiation damage and its effect on bystander cells in real time. First, a flow shear model system, which would provide us a near in vivo situation where endothelial cells in the presence of extra cellular matrix experiencing continuous flow shear stress, will be used. Endothelial cells on matri-gel (simulated extra cellular matrix) will be subjected to physiological flow shear (that occurs in normal blood vessels). Second, a unique tool (Single nano particle/single live cell/single molecule microscopy and spectroscopy; Figure A) will be used tomore » track the molecular trafficking by single live cell imaging. Single molecule chemical microscopy allows one to single out and study rare events that otherwise might be lost in assembled average measurement, and monitor many target single molecules simultaneously in real-time. Multi color single novel metal nanoparticle probes allow one to prepare multicolor probes (Figure B) to monitor many single components (events) simultaneously and perform multi-complex analysis in real-time. These nano-particles resist to photo bleaching and hence serve as probes for unlimited timeframe of analysis. Single live cell microscopy allows one to image many single cells simultaneously in real-time. With the combination of these unique tools, we will be able to study under near-physiological conditions the cellular and sub-cellular responses (even subtle changes at one molecule level) to low and very low doses of low LET radiation in real time (milli-second or nano-second) at sub-10 nanometer spatial resolution. This would allow us to precisely identify, at least in part, the molecular mediators that are responsible of radiation damage in the irradiated cells and the mediators that are responsible for initiating the signaling in the neighboring cells. Endothelial cells subjected to flow shear (2 dynes/cm2 or 16 dynes/cm2) and exposed to 0.1, 1 and 10 cGy on coverslips will be examined for (a) low LET radiation-induced alterations of cellular function and its physiological relevance in real time; and (b) radiation damage triggered bystander effect on the neighboring unirradiated cells. First, to determine the low LET radiation induced alteration of cellular function we will examine: (i) the real time transformation of single membrane transporters in single living cells; (ii) the pump efficiency of membrane efflux pump of live cells in real time at the molecular level; (iii) the kinetics of single-ligand receptor interaction on single live cell surface (Figure C); and (iv) alteration in chromosome replication in living cell. Second, to study the radiation triggered bystander responses, we will examine one of the key signaling pathway i.e. TNF- alpha/NF-kappa B mediated signaling. TNF-alpha specific nano particle sensors (green) will be developed to detect the releasing dynamics, transport mechanisms and ligand-receptor binding on live cell surface in real time. A second sensor (blue) will be developed to simultaneously monitor the track of NF-kB inside the cell. The proposed nano-particle optics approach would complement our DOE funded study on biochemical mechanisms of TNF-alpha- NF-kappa B-mediated bystander effect.« less

Single-particle states vs. collective modes: friends or enemies ?

NASA Astrophysics Data System (ADS)

Otsuka, T.; Tsunoda, Y.; Togashi, T.; Shimizu, N.; Abe, T.

2018-05-01

The quantum self-organization is introduced as one of the major underlying mechanisms of the quantum many-body systems. In the case of atomic nuclei as an example, two types of the motion of nucleons, single-particle states and collective modes, dominate the structure of the nucleus. The collective mode arises as the balance between the effect of the mode-driving force (e.g., quadrupole force for the ellipsoidal deformation) and the resistance power against it. The single-particle energies are one of the sources to produce such resistance power: a coherent collective motion is more hindered by larger spacings between relevant single particle states. Thus, the single-particle state and the collective mode are "enemies" against each other. However, the nuclear forces are rich enough so as to enhance relevant collective mode by reducing the resistance power by changing single-particle energies for each eigenstate through monopole interactions. This will be verified with the concrete example taken from Zr isotopes. Thus, the quantum self-organization occurs: single-particle energies can be self-organized by (i) two quantum liquids, e.g., protons and neutrons, (ii) monopole interaction (to control resistance). In other words, atomic nuclei are not necessarily like simple rigid vases containing almost free nucleons, in contrast to the naïve Fermi liquid picture. Type II shell evolution is considered to be a simple visible case involving excitations across a (sub)magic gap. The quantum self-organization becomes more important in heavier nuclei where the number of active orbits and the number of active nucleons are larger.

Selective counting and sizing of single virus particles using fluorescent aptamer-based nanoparticle tracking analysis.

PubMed

Szakács, Zoltán; Mészáros, Tamás; de Jonge, Marien I; Gyurcsányi, Róbert E

2018-05-30

Detection and counting of single virus particles in liquid samples are largely limited to narrow size distribution of viruses and purified formulations. To address these limitations, here we propose a calibration-free method that enables concurrently the selective recognition, counting and sizing of virus particles as demonstrated through the detection of human respiratory syncytial virus (RSV), an enveloped virus with a broad size distribution, in throat swab samples. RSV viruses were selectively labeled through their attachment glycoproteins (G) with fluorescent aptamers, which further enabled their identification, sizing and counting at the single particle level by fluorescent nanoparticle tracking analysis. The proposed approach seems to be generally applicable to virus detection and quantification. Moreover, it could be successfully applied to detect single RSV particles in swab samples of diagnostic relevance. Since the selective recognition is associated with the sizing of each detected particle, this method enables to discriminate viral elements linked to the virus as well as various virus forms and associations.

Maximum Mass-Particle Velocities in Kantor's Information Mechanics

NASA Astrophysics Data System (ADS)

Sverdlik, Daniel I.

1989-02-01

Kantor's information mechanics links phenomena previously regarded as not treatable by a single theory. It is used here to calculate the maximum velocities ν m of single particles. For the electron, ν m/c≈1-1.253 814×10-77. The maximum ν m corresponds to ν m/c≈1-1.097864×10-122 for a single mass particle with a rest mass of 3.078 496×10-5g. This is the fastest that matter can move. Either information mechanics or classical mechanics can be used to show that ν m is less for heavier particles. That ν m is less for lighter particles can be deduced from an information mechanics argument alone.

Optical trapping and rotation of airborne absorbing particles with a single focused laser beam

NASA Astrophysics Data System (ADS)

Lin, Jinda; Li, Yong-qing

2014-03-01

We measure the periodic circular motion of single absorbing aerosol particles that are optically trapped with a single focused Gaussian beam and rotate around the laser propagation direction. The scattered light from the trapped particle is observed to be directional and change periodically at 0.4-20 kHz. The instantaneous positions of the moving particle within a rotation period are measured by a high-speed imaging technique using a charge coupled device camera and a repetitively pulsed light-emitting diode illumination. The centripetal acceleration of the trapped particle as high as ˜20 times the gravitational acceleration is observed and is attributed to the photophoretic forces.

The relationship between dielectrophoretic and impedance response of dielectric particles immersed in aqueous media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bahaj, A.E.; Bailey, A.G.

1985-09-01

Dielectrophoretic force measurements on isolated 50-..mu..m diameter particles of divinylbenzene (DVB) suspended in aqueous solutions show that force is dependent on relaxation mechanisms present at the particle-liquid interface. Measurements on single particles have been extended to measurements on populations of particles. The impedance of aqueous suspensions of particles contained in a gold-plated electrode test cell has been measured over a range of frequency. Data are presented in the form of Cole-Cole plots. It is shown that the dielectrophoretic response of single particles can be related to the frequency-dependent impedance behavior of suspensions of similar particles.

Habitat Design Considerations for Implementing Solar Particle Event Radiation Protection

NASA Technical Reports Server (NTRS)

Simon, Mathew A.; Clowdsley, Martha S.; Walker, Steven A.

2013-01-01

Radiation protection is an important habitat design consideration for human exploration missions beyond Low Earth Orbit. Fortunately, radiation shelter concepts can effectively reduce astronaut exposure for the relatively low proton energies of solar particle events, enabling moderate duration missions of several months before astronaut exposure (galactic cosmic ray and solar particle event) approaches radiation exposure limits. In order to minimize habitat mass for increasingly challenging missions, design of radiation shelters must minimize dedicated, single-purpose shielding mass by leveraging the design and placement of habitat subsystems, accommodations, and consumables. NASA's Advanced Exploration Systems RadWorks Storm Shelter Team has recently designed and performed radiation analysis on several low dedicated mass shelter concepts for a year-long mission. This paper describes habitat design considerations identified during the study's radiation analysis. These considerations include placement of the shelter within a habitat for improved protection, integration of human factors guidance for sizing shelters, identification of potential opportunities for habitat subsystems to compromise on individual subsystem performances for overall vehicle mass reductions, and pre-configuration of shelter components for reduced deployment times.

Composition inversion in mixtures of binary colloids and polymer

NASA Astrophysics Data System (ADS)

Zhang, Isla; Pinchaipat, Rattachai; Wilding, Nigel B.; Faers, Malcolm A.; Bartlett, Paul; Evans, Robert; Royall, C. Patrick

2018-05-01

Understanding the phase behaviour of mixtures continues to pose challenges, even for systems that might be considered "simple." Here, we consider a very simple mixture of two colloidal and one non-adsorbing polymer species, which can be simplified even further to a size-asymmetrical binary mixture, in which the effective colloid-colloid interactions depend on the polymer concentration. We show that this basic system exhibits surprisingly rich phase behaviour. In particular, we enquire whether such a system features only a liquid-vapor phase separation (as in one-component colloid-polymer mixtures) or whether, additionally, liquid-liquid demixing of two colloidal phases can occur. Particle-resolved experiments show demixing-like behaviour, but when combined with bespoke Monte Carlo simulations, this proves illusory, and we reveal that only a single liquid-vapor transition occurs. Progressive migration of the small particles to the liquid phase as the polymer concentration increases gives rise to composition inversion—a maximum in the large particle concentration in the liquid phase. Close to criticality, the density fluctuations are found to be dominated by the larger colloids.

Current models of the intensely ionizing particle environment in space

NASA Technical Reports Server (NTRS)

Adams, James H., Jr.

1988-01-01

The Cosmic Ray Effects on MicroElectronics (CREME) model that is currently in use to estimate single event effect rates in spacecraft is described. The CREME model provides a description of the radiation environment in interplanetary space near the orbit of the earth that contains no major deficiencies. The accuracy of the galactic cosmic ray model is limited by the uncertainties in solar modulation. The model for solar energetic particles could be improved by making use of all the data that has been collected on solar energetic particle events. There remain major uncertainties about the environment within the earth's magnetosphere, because of the uncertainties over the charge states of the heavy ions in the anomalous component and solar flares, and because of trapped heavy ions. The present CREME model is valid only at 1 AU, but it could be extended to other parts of the heliosphere. There is considerable data on the radiation environment from 0.2 to 35 AU in the ecliptic plane. This data could be used to extend the CREME model.

Relativistic distribution function for particles with spin at local thermodynamical equilibrium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Becattini, F., E-mail: becattini@fi.infn.it; INFN Sezione di Firenze, Florence; Universität Frankfurt, Frankfurt am Main

2013-11-15

We present an extension of relativistic single-particle distribution function for weakly interacting particles at local thermodynamical equilibrium including spin degrees of freedom, for massive spin 1/2 particles. We infer, on the basis of the global equilibrium case, that at local thermodynamical equilibrium particles acquire a net polarization proportional to the vorticity of the inverse temperature four-vector field. The obtained formula for polarization also implies that a steady gradient of temperature entails a polarization orthogonal to particle momentum. The single-particle distribution function in momentum space extends the so-called Cooper–Frye formula to particles with spin 1/2 and allows us to predict theirmore » polarization in relativistic heavy ion collisions at the freeze-out. -- Highlights: •Single-particle distribution function in local thermodynamical equilibrium with spin. •Polarization of spin 1/2 particles in a fluid at local thermodynamical equilibrium. •Prediction of a new effect: a steady gradient of temperature induces a polarization. •Application to the calculation of polarization in relativistic heavy ion collisions.« less

Reciprocity relationships in vector acoustics and their application to vector field calculations.

PubMed

Deal, Thomas J; Smith, Kevin B

2017-08-01

The reciprocity equation commonly stated in underwater acoustics relates pressure fields and monopole sources. It is often used to predict the pressure measured by a hydrophone for multiple source locations by placing a source at the hydrophone location and calculating the field everywhere for that source. A similar equation that governs the orthogonal components of the particle velocity field is needed to enable this computational method to be used for acoustic vector sensors. This paper derives a general reciprocity equation that accounts for both monopole and dipole sources. This vector-scalar reciprocity equation can be used to calculate individual components of the received vector field by altering the source type used in the propagation calculation. This enables a propagation model to calculate the received vector field components for an arbitrary number of source locations with a single model run for each vector field component instead of requiring one model run for each source location. Application of the vector-scalar reciprocity principle is demonstrated with analytic solutions for a range-independent environment and with numerical solutions for a range-dependent environment using a parabolic equation model.

Deciphering dynamics of clathrin-mediated endocytosis in a living organism

PubMed Central

Heidotting, Spencer P.; Huber, Scott D.

2016-01-01

Current understanding of clathrin-mediated endocytosis (CME) dynamics is based on detection and tracking of fluorescently tagged clathrin coat components within cultured cells. Because of technical limitations inherent to detection and tracking of single fluorescent particles, CME dynamics is not characterized in vivo, so the effects of mechanical cues generated during development of multicellular organisms on formation and dissolution of clathrin-coated structures (CCSs) have not been directly observed. Here, we use growth rates of fluorescence signals obtained from short CCS intensity trace fragments to assess CME dynamics. This methodology does not rely on determining the complete lifespan of individual endocytic assemblies. Therefore, it allows for real-time monitoring of spatiotemporal changes in CME dynamics and is less prone to errors associated with particle detection and tracking. We validate the applicability of this approach to in vivo systems by demonstrating the reduction of CME dynamics during dorsal closure of Drosophila melanogaster embryos. PMID:27458134

Application of quantum-behaved particle swarm optimization to motor imagery EEG classification.

PubMed

Hsu, Wei-Yen

2013-12-01

In this study, we propose a recognition system for single-trial analysis of motor imagery (MI) electroencephalogram (EEG) data. Applying event-related brain potential (ERP) data acquired from the sensorimotor cortices, the system chiefly consists of automatic artifact elimination, feature extraction, feature selection and classification. In addition to the use of independent component analysis, a similarity measure is proposed to further remove the electrooculographic (EOG) artifacts automatically. Several potential features, such as wavelet-fractal features, are then extracted for subsequent classification. Next, quantum-behaved particle swarm optimization (QPSO) is used to select features from the feature combination. Finally, selected sub-features are classified by support vector machine (SVM). Compared with without artifact elimination, feature selection using a genetic algorithm (GA) and feature classification with Fisher's linear discriminant (FLD) on MI data from two data sets for eight subjects, the results indicate that the proposed method is promising in brain-computer interface (BCI) applications.

A complete solution classification and unified algorithmic treatment for the one- and two-step asymmetric S-transverse mass event scale statistic

NASA Astrophysics Data System (ADS)

Walker, Joel W.

2014-08-01

The M T2, or "s-transverse mass", statistic was developed to associate a parent mass scale to a missing transverse energy signature, given that escaping particles are generally expected in pairs, while collider experiments are sensitive to just a single transverse momentum vector sum. This document focuses on the generalized extension of that statistic to asymmetric one- and two-step decay chains, with arbitrary child particle masses and upstream missing transverse momentum. It provides a unified theoretical formulation, complete solution classification, taxonomy of critical points, and technical algorithmic prescription for treatment of the event scale. An implementation of the described algorithm is available for download, and is also a deployable component of the author's selection cut software package AEAC uS (Algorithmic Event Arbiter and C ut Selector). appendices address combinatoric event assembly, algorithm validation, and a complete pseudocode.

An optimized formulation of a thermostable spray dried virus-like particles vaccine against human papillomavirus

PubMed Central

Saboo, Sugandha; Tumban, Ebenezer; Peabody, Julianne; Wafula, Denis; Peabody, David S.; Chackerian, Bryce; Muttil, Pavan

2016-01-01

Existing vaccines against human papillomavirus (HPV) require continuous cold-chain storage. Previously, we developed a bacteriophage virus-like particle (VLP) based vaccine for Human Papillomavirus (HPV) infection, which elicits broadly neutralizing antibodies against diverse HPV types. Here, we formulated these VLPs into a thermostable dry powder using a multi-component excipient system and by optimizing the spray drying parameters using a half-factorial design approach. Dry powder VLPs were stable after spray drying and after long-term storage at elevated temperatures. Immunization of mice with a single dose of reconstituted dry powder VLPs that were stored at 37°C for more than a year elicited high anti-L2 IgG antibody titers. Spray dried thermostable, broadly protective L2 bacteriophage VLPs vaccine could be accessible to remote regions of the world (where ~84% of cervical cancer patients reside) by eliminating the cold-chain requirement during transportation and storage. PMID:27019231

Mass Spectrometry of Single Particles Levitated in an Electrodynamic Balance: Applications to Laboratory Atmospheric Chemistry Research

NASA Astrophysics Data System (ADS)

Birdsall, A.; Krieger, U. K.; Keutsch, F. N.

2017-12-01

Dynamic changes to atmospheric aerosol particle composition (e.g., originating from evaporation/condensation, oxidative aging, or aqueous-phase chemical reactions) impact particle properties with importance for understanding particle effects on climate and human health. These changes can take place over the entire lifetime of an atmospheric particle, which can extend over multiple days. Previous laboratory studies of such processes have included analyzing single particles suspended in a levitation device, such as an electrodynamic balance (EDB), an optical levitator, or an acoustic trap, using optical detection techniques. However, studying chemically complex systems can require an analytical method, such as mass spectrometry, that provides more molecular specificity. Existing work coupling particle levitation with mass spectrometry is more limited and largely has consisted of acoustic levitation of millimeter-sized droplets.In this work an EDB has been coupled with a custom-built ionization source and commercial time-of-flight mass spectrometer (MS) as a platform for laboratory atmospheric chemistry research. Single charged particles (radius 10 μm) have been injected into an EDB, levitated for an arbitrarily long period of time, and then transferred to a vaporization-corona discharge ionization region for MS analysis. By analyzing a series of particles of identical composition, residing in the controlled environment of the EDB for varying times, we can trace the chemical evolution of a particle over hours or days, appropriate timescales for understanding transformations of atmospheric particles.To prove the concept of our EDB-MS system, we have studied the evaporation of particles consisting of polyethylene glycol (PEG) molecules of mixed chain lengths, used as a benchmark system. Our system can quantify the composition of single particles (see Figure for sample spectrum of a single PEG-200 particle: PEG parent ions labeled with m/z, known PEG fragment ions labeled with *). Furthermore, our measured evaporation rates are consistent with a kinetic model. We will discuss future types of experiments enabled by EDB-MS, by allowing detailed chemical changes of a particle in a controlled laboratory environment to be monitored on timescales mimicking those of particles in the atmosphere.

Fast time-resolved aerosol collector: proof of concept

NASA Astrophysics Data System (ADS)

Yu, X.-Y.; Cowin, J. P.; Iedema, M. J.; Ali, H.

2010-10-01

Atmospheric particles can be collected in the field on substrates for subsequent laboratory analysis via chemically sensitive single particle methods such as scanning electron microscopy with energy dispersive x-ray analysis. With moving substrates time resolution of seconds to minutes can be achieved. In this paper, we demonstrate how to increase the time resolution when collecting particles on a substrate to a few milliseconds to provide real-time information. Our fast time-resolved aerosol collector ("Fast-TRAC") microscopically observes the particle collection on a substrate and records an on-line video. Particle arrivals are resolved to within a single frame (4-17 ms in this setup), and the spatial locations are matched to the subsequent single particle analysis. This approach also provides in-situ information on particle size and number concentration. Applications are expected in airborne studies of cloud microstructure, pollution plumes, and surface long-term monitoring.

Fast time-resolved aerosol collector: proof of concept

NASA Astrophysics Data System (ADS)

Yu, X.-Y.; Cowin, J. P.; Iedema, M. J.; Ali, H.

2010-06-01

Atmospheric particles can be collected in the field on substrates for subsequent laboratory analysis via chemically sensitive single particle methods such as scanning electron microscopy with energy dispersive x-ray analysis. With moving substrates time resolution of seconds to minutes can be achieved. In this paper, we demonstrate how to increase the time resolution when collecting particles on a substrate to a few milliseconds to provide real-time information. Our fast time-resolved aerosol collector ("Fast-TRAC") microscopically observes the particle collection on a substrate and records an on-line video. Particle arrivals are resolved to within a single frame (4-17 ms in this setup), and the spatial locations are matched to the subsequent single particle analysis. This approach also provides in-situ information on particle size and number concentration. Applications are expected in airborne studies of cloud microstructure, pollution plumes, and surface long-term monitoring.

Comparison of mineral dust and droplet residuals measured with two single particle aerosol mass spectrometers

NASA Astrophysics Data System (ADS)

Wonaschütz, Anna; Ludwig, Wolfgang; Zawadowicz, Maria; Hiranuma, Naruki; Hitzenberger, Regina; Cziczo, Daniel; DeMott, Paul; Möhler, Ottmar

2017-04-01

Single Particle mass spectrometers are used to gain information on the chemical composition of individual aerosol particles, aerosol mixing state, and other valuable aerosol characteristics. During the Mass Spectrometry Intercomparison at the Fifth Ice Nucleation (FIN-01) Workshop, the new LAAPTOF single particle aerosol mass spectrometer (AeroMegt GmbH) was conducting simultaneous measurements together with the PALMS (Particle Analysis by Laser Mass Spectrometry) instrument. The aerosol particles were sampled from the AIDA chamber during ice cloud expansion experiments. Samples of mineral dust and ice droplet residuals were measured simultaneously. In this work, three expansion experiments are chosen for a comparison between the two mass spectrometers. A fuzzy clustering routine is used to group the spectra. Cluster centers describing the ensemble of particles are compared. First results show that while differences in the peak heights are likely due to the use of an amplifier in PALMS, cluster centers are comparable.

The ozonolysis of primary aliphatic amines in single and multicomponent fine particles

NASA Astrophysics Data System (ADS)

Zahardis, J.; Geddes, S.; Petrucci, G. A.

2007-10-01

The oxidative processing by ozone of the particulate amines octadecylamine (ODA) and hexadecylamine (HDA) is reported. Ozonolysis of these amines resulted in strong NO2- and NO3- ion signals that increased with ozone exposure as monitored by photoelectron resonance capture ionization aerosol mass spectrometry. These products suggest a mechanism of progressive oxidation of the particulate amines to nitro alkanes. Additionally, a strong ion signal at 125 m/z is assigned to the ion NO3-(HNO3). For ozonized mixed particles containing ODA or HDA + oleic acid (OL), with pO3≥3×10^{-7 atm, imine, secondary amide, and tertiary amide products were measured. These products most likely arise from reactions of amines with aldehydes (for imines) and stabilized Criegee intermediates (SCI) or secondary ozonides (for amides) from the fatty acid. The routes to amides via SCI and/or secondary ozonides was shown to be more important than comparable amide forming reactions between amines and organic acids, using azelaic acid as a test compound. Finally, direct evidence is provided for the formation of a surface barrier in the ODA + OL reaction system that resulted in the retention of OL at high ozone exposures (up to 10-3 atm for 17 s). This effect was not observed in HDA + OL or single component OL particles, suggesting that it may be a species-specific surfactant effect from an in situ generated amide or imine. Implications to tropospheric chemistry, including particle bound amines as sources of oxidized gas phase nitrogen species (e.g. NO2, NO3), formation of nitrogen enriched HULIS via ozonolysis of amines and source apportionment are discussed.}

Structure and Dynamics of Bimodal Colloidal Dispersions in a Low-Molecular-Weight Polymer Solution.

PubMed

Zhang, Fan; Allen, Andrew J; Levine, Lyle E; Tsai, De-Hao; Ilavsky, Jan

2017-03-21

We present an experimental study of the structural and dynamical properties of bimodal, micrometer-sized colloidal dispersions (size ratio ≈ 2) in an aqueous solution of low-molecular-weight polymer (polyethylene glycol 2000) using synchrotron ultra-small angle X-ray scattering (USAXS) and USAXS-based X-ray photon correlation spectroscopy. We fixed the volume fraction of the large particles at 5% and systematically increased the volume fraction of the small particles from 0 to 5% to evaluate their effects on the structure and dynamics. The bimodal dispersions were homogenous through the investigated parameter space. We found that the partial structure factors can be satisfactorily retrieved for the bimodal colloidal dispersions using a Percus-Yevick hard-sphere potential when the size distributions of the particles were taken into account. We also found that the partial structure factor between the large particles did not exhibit a significant variation with increasing volume fraction of the small particles, whereas the isothermal compressibility of the binary mixture was found to decrease with increasing volume fraction of the small particles. The dynamics of single-component large-particle dispersion obey the principles of de Gennes narrowing, where the wave vector dependence of the interparticle diffusion coefficient is inversely proportional to the interparticle structure factor. The dynamics of the bimodal dispersions demonstrate a strong dependence on the fraction of small particles. We also made a comparison between the experimental effective dynamic viscosity of the bimodal dispersion with the theoretical predictions, which suggest that the complex mutual interactions between the large and small particles have a strong effect on the dynamic behaviors of bimodal dispersions.

Optical properties of size-resolved particles at a Hong Kong urban site during winter

NASA Astrophysics Data System (ADS)

Gao, Yuan; Lai, Senchao; Lee, Shun-Cheng; Yau, Pui Shan; Huang, Yu; Cheng, Yan; Wang, Tao; Xu, Zheng; Yuan, Chao; Zhang, Yingyi

2015-03-01

Visibility degradation in Hong Kong is related to the city's serious air pollution problems. To investigate the aerosols' optical properties and their relationship with the chemical composition and size distribution of the particles, a monitoring campaign was conducted at an urban site in the early winter period (from October to December, 2010). The particle light scattering coefficient (Bsp) and absorption coefficient (Bap) were measured. Two collocated Micro-Orifice Uniform Deposit Impactor samplers (MOUDI110, MSP, USA) with nominal 50% cut-off aerodynamic diameters of 18, 10, 5.6, 3.2, 1.8, 1, 0.56, 0.32, 0.18, 0.1, and 0.056 μm were used to collect size-resolved particle samples. The average Bsp and Bap were 201.96 ± 105.82 Mm- 1 and 39.91 ± 19.16 Mm- 1, with an average single scattering albedo (ωo) of 0.82 ± 0.07. The theoretical method of light extinction calculation was used to determine the extinction of the size-resolved particulate matters (PM). The reconstructed light scattering coefficient correlated well with the measured scattering value in the Hong Kong urban area. Droplet mode (0.56-1.8 μm) particles contributed most to the particle light extinction (~ 69%). Organic matter, ammonium sulphate and elemental carbon were the key components causing visibility degradation in the droplet (0.56-1.8 μm) and condensation (0.1-0.56 μm) size ranges. Five sources contributing to particle light extinction have been identified using positive matrix factorisation (PMF). Traffic/engine exhausts and secondary aerosols accounted for ~ 36% and ~ 32% of particle light extinction, respectively, followed by sea salt (15%). The remaining sources, soil/fugitive dust and tire dust, contributed by ~ 10% and 7%, respectively, to particle light extinction.

A Hidden Markov Model for Single Particle Tracks Quantifies Dynamic Interactions between LFA-1 and the Actin Cytoskeleton

PubMed Central

Das, Raibatak; Cairo, Christopher W.; Coombs, Daniel

2009-01-01

The extraction of hidden information from complex trajectories is a continuing problem in single-particle and single-molecule experiments. Particle trajectories are the result of multiple phenomena, and new methods for revealing changes in molecular processes are needed. We have developed a practical technique that is capable of identifying multiple states of diffusion within experimental trajectories. We model single particle tracks for a membrane-associated protein interacting with a homogeneously distributed binding partner and show that, with certain simplifying assumptions, particle trajectories can be regarded as the outcome of a two-state hidden Markov model. Using simulated trajectories, we demonstrate that this model can be used to identify the key biophysical parameters for such a system, namely the diffusion coefficients of the underlying states, and the rates of transition between them. We use a stochastic optimization scheme to compute maximum likelihood estimates of these parameters. We have applied this analysis to single-particle trajectories of the integrin receptor lymphocyte function-associated antigen-1 (LFA-1) on live T cells. Our analysis reveals that the diffusion of LFA-1 is indeed approximately two-state, and is characterized by large changes in cytoskeletal interactions upon cellular activation. PMID:19893741

Magnetophoretic circuits for digital control of single particles and cells

NASA Astrophysics Data System (ADS)

Lim, Byeonghwa; Reddy, Venu; Hu, Xinghao; Kim, Kunwoo; Jadhav, Mital; Abedini-Nassab, Roozbeh; Noh, Young-Woock; Lim, Yong Taik; Yellen, Benjamin B.; Kim, Cheolgi

2014-05-01

The ability to manipulate small fluid droplets, colloidal particles and single cells with the precision and parallelization of modern-day computer hardware has profound applications for biochemical detection, gene sequencing, chemical synthesis and highly parallel analysis of single cells. Drawing inspiration from general circuit theory and magnetic bubble technology, here we demonstrate a class of integrated circuits for executing sequential and parallel, timed operations on an ensemble of single particles and cells. The integrated circuits are constructed from lithographically defined, overlaid patterns of magnetic film and current lines. The magnetic patterns passively control particles similar to electrical conductors, diodes and capacitors. The current lines actively switch particles between different tracks similar to gated electrical transistors. When combined into arrays and driven by a rotating magnetic field clock, these integrated circuits have general multiplexing properties and enable the precise control of magnetizable objects.

Improving z-tracking accuracy in the two-photon single-particle tracking microscope.

PubMed

Liu, C; Liu, Y-L; Perillo, E P; Jiang, N; Dunn, A K; Yeh, H-C

2015-10-12

Here, we present a method that can improve the z-tracking accuracy of the recently invented TSUNAMI (Tracking of Single particles Using Nonlinear And Multiplexed Illumination) microscope. This method utilizes a maximum likelihood estimator (MLE) to determine the particle's 3D position that maximizes the likelihood of the observed time-correlated photon count distribution. Our Monte Carlo simulations show that the MLE-based tracking scheme can improve the z-tracking accuracy of TSUNAMI microscope by 1.7 fold. In addition, MLE is also found to reduce the temporal correlation of the z-tracking error. Taking advantage of the smaller and less temporally correlated z-tracking error, we have precisely recovered the hybridization-melting kinetics of a DNA model system from thousands of short single-particle trajectories in silico . Our method can be generally applied to other 3D single-particle tracking techniques.

Improving z-tracking accuracy in the two-photon single-particle tracking microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, C.; Liu, Y.-L.; Perillo, E. P.

Here, we present a method that can improve the z-tracking accuracy of the recently invented TSUNAMI (Tracking of Single particles Using Nonlinear And Multiplexed Illumination) microscope. This method utilizes a maximum likelihood estimator (MLE) to determine the particle's 3D position that maximizes the likelihood of the observed time-correlated photon count distribution. Our Monte Carlo simulations show that the MLE-based tracking scheme can improve the z-tracking accuracy of TSUNAMI microscope by 1.7 fold. In addition, MLE is also found to reduce the temporal correlation of the z-tracking error. Taking advantage of the smaller and less temporally correlated z-tracking error, we havemore » precisely recovered the hybridization-melting kinetics of a DNA model system from thousands of short single-particle trajectories in silico. Our method can be generally applied to other 3D single-particle tracking techniques.« less

Single-particle energies and density of states in density functional theory

NASA Astrophysics Data System (ADS)

van Aggelen, H.; Chan, G. K.-L.

2015-07-01

Time-dependent density functional theory (TD-DFT) is commonly used as the foundation to obtain neutral excited states and transition weights in DFT, but does not allow direct access to density of states and single-particle energies, i.e. ionisation energies and electron affinities. Here we show that by extending TD-DFT to a superfluid formulation, which involves operators that break particle-number symmetry, we can obtain the density of states and single-particle energies from the poles of an appropriate superfluid response function. The standard Kohn- Sham eigenvalues emerge as the adiabatic limit of the superfluid response under the assumption that the exchange- correlation functional has no dependence on the superfluid density. The Kohn- Sham eigenvalues can thus be interpreted as approximations to the ionisation energies and electron affinities. Beyond this approximation, the formalism provides an incentive for creating a new class of density functionals specifically targeted at accurate single-particle eigenvalues and bandgaps.

Real-time detection method and system for identifying individual aerosol particles

DOEpatents

Gard, Eric E [San Francisco, CA; Coffee, Keith R [Patterson, CA; Frank, Matthias [Oakland, CA; Tobias, Herbert J [Kensington, CA; Fergenson, David P [Alamo, CA; Madden, Norm [Livermore, CA; Riot, Vincent J [Berkeley, CA; Steele, Paul T [Livermore, CA; Woods, Bruce W [Livermore, CA

2007-08-21

An improved method and system of identifying individual aerosol particles in real time. Sample aerosol particles are collimated, tracked, and screened to determine which ones qualify for mass spectrometric analysis based on predetermined qualification or selection criteria. Screening techniques include one or more of determining particle size, shape, symmetry, and fluorescence. Only qualifying particles passing all screening criteria are subject to desorption/ionization and single particle mass spectrometry to produce corresponding test spectra, which is used to determine the identities of each of the qualifying aerosol particles by comparing the test spectra against predetermined spectra for known particle types. In this manner, activation cycling of a particle ablation laser of a single particle mass spectrometer is reduced.

Stretched proton-neutron configurations in fp-shell nuclei (II). Systematics

NASA Astrophysics Data System (ADS)

von Neumann-Cosel, P.; Fister, U.; Jahn, R.; Schenk, P.; Trelle, T. K.; Wenzel, D.; Wienands, U.

1994-03-01

The systematics of the binding energies of stretched proton-neutron configurations ( f{7}/{2}, g{9}/{2}) 8 -, ( p{3}/{2}, g{9}/{2}) 6 -, ( g{9}/{2}, p{3}/{2}) 6- and ( g{9}/{2}) 29 + are studied over a wide range of f p-shell nuclei. The effective proton-neutron interaction energies deduced from the data are nearly constant for ( p{3}/{2}, g{9}/{2}) 6 -and ( g{9}/{2}) 29 + states while the ( f{7}/{2}, g{9}/{2}) 8 - configuration reveals an additional repulsive term proportional to the partial filling of the f{7}/{2} orbit in the target ground state. Two-body matrix elements are extracted. A crude shell model, which predicts that the excitation energy of a stretched state is equal to the sum of the single-particle energies, works well for the 6 - and 9 + states, but fails for the 8 - levels due to neglect of the additional interactions described above. The physics underlying the empirically introduced basic assumptions of the crude shell model is discussed. The binding energies are found to be linearly dependent on the mass number A and the isospin Tz component and are well described by the weak-coupling model of Bansal and French. The derived parameters agree with averaged values of a similar analysis for the single-particle states in the corresponding odd-even neighbours. The data indicate a significant change of the particle-hole energies with closure of the proton f{7}/{2} shell.

Scalability Test of Multiscale Fluid-Platelet Model for Three Top Supercomputers

PubMed Central

Zhang, Peng; Zhang, Na; Gao, Chao; Zhang, Li; Gao, Yuxiang; Deng, Yuefan; Bluestein, Danny

2016-01-01

We have tested the scalability of three supercomputers: the Tianhe-2, Stampede and CS-Storm with multiscale fluid-platelet simulations, in which a highly-resolved and efficient numerical model for nanoscale biophysics of platelets in microscale viscous biofluids is considered. Three experiments involving varying problem sizes were performed: Exp-S: 680,718-particle single-platelet; Exp-M: 2,722,872-particle 4-platelet; and Exp-L: 10,891,488-particle 16-platelet. Our implementations of multiple time-stepping (MTS) algorithm improved the performance of single time-stepping (STS) in all experiments. Using MTS, our model achieved the following simulation rates: 12.5, 25.0, 35.5 μs/day for Exp-S and 9.09, 6.25, 14.29 μs/day for Exp-M on Tianhe-2, CS-Storm 16-K80 and Stampede K20. The best rate for Exp-L was 6.25 μs/day for Stampede. Utilizing current advanced HPC resources, the simulation rates achieved by our algorithms bring within reach performing complex multiscale simulations for solving vexing problems at the interface of biology and engineering, such as thrombosis in blood flow which combines millisecond-scale hematology with microscale blood flow at resolutions of micro-to-nanoscale cellular components of platelets. This study of testing the performance characteristics of supercomputers with advanced computational algorithms that offer optimal trade-off to achieve enhanced computational performance serves to demonstrate that such simulations are feasible with currently available HPC resources. PMID:27570250

Chalcogenide nanocrystal assembly: Controlling heterogeneity and modulating heterointerfaces

NASA Astrophysics Data System (ADS)

Davis, Jessica

This dissertation work is focused on developing methods to facilitate charge transport in heterostructured materials that comprise a nanoscale component. Multicomponent semiconductor materials were prepared by (1) spin coating of discrete nanomaterials onto porous silicon (pSi) or (2) self-assembly. Spin-coating of colloidal quantum dot (QD) PbS solutions was employed to create prototype PbS QD based radiation detection devices using porous silicon (pSi) as an n-type support and charge transport material. These devices were initially tested as a photodetector to ascertain the possibility of their use in high energy radiation detection. Short chain thiolate ligands (4-fluorothiophenolate) and anion passivation at the particle interface were evaluated to augment interparticle transport. However, the samples showed minimum interaction with the light source possibly due to poor infiltration into the pSi. The second project was also driven by the potential synergistic properties that can be achieved in multicomponent metal chalcogenide nanostructures, potentially useful in optoelectronic devices. Working with well-established methods for single component metal chalcogenide (MQ) particle gels this dissertation research sought to develop practical methods for co-gelation of different component particles with complimentary functionalities. By monitoring the kinetics of aggregation using time resolved dynamic light scattering and NMR spectroscopy the kinetics of aggregation of the two most common crystal structures for CdQ nanocrystals was studied and it was determined that the hexagonal (wurtzite) crystal structure aggregated faster than the cubic (zinc blende) crystal structure. For gel coupling of nanoparticles with differing Q (Q=S, Se and Te), once we accounted for the crystal structure effects, it was determined that the relative redox characteristics of Q govern the reaction rate. The oxidative sol-gel assembly routes were also employed to fabricate metal chalcogenide NC gels with different NC components with control over the degree of mixing. In order to control the degree of mixing, the factors that underscore sol-gel oxidative assembly were elucidated and the aggregation and gelation kinetics of metal chalcogenide QDs were monitored through time-resolved dynamic light scattering (TR-DLS), and nuclear magnetic resonance spectroscopy (NMR). Through these kinetic studies of the surface speciation of metal chalcogenides, control over heterogeneity in dual component CdSe-ZnS system, was achieved through adjustment of the capping ligand, the native crystal structure and the chalcogenide, thereby changing the relative rates of assembly for each component independently.

Magnetic properties of iron oxide photolytically produced from Fe(CO)5 impregnated porous glass

NASA Astrophysics Data System (ADS)

Borelli, N. F.; Morse, D. L.; Schreurs, J. W. H.

1983-06-01

This article discusses the magnetic properties observed in porous glasses impregnated with metal carbonyls after exposure to light. In the photolyzed and consolidated glasses both superparamagnetic and single domain ferrimagnetic particles were found to be present, with the single domain particles having an exceedingly high coercive force. The concentration ratio between superparamagnetic and single domain particles depends strongly on temperature. An analysis of the observed phenomena is given.

Digital Microfluidics Assisted Sealing of Individual Magnetic Particles in Femtoliter-Sized Reaction Wells for Single-Molecule Detection.

PubMed

Decrop, Deborah; Ruiz, Elena Pérez; Kumar, Phalguni Tewari; Tripodi, Lisa; Kokalj, Tadej; Lammertyn, Jeroen

2017-01-01

Digital microfluidics has emerged in the last years as a promising liquid handling technology for a variety of applications. Here, we describe in detail how to build up an electrowetting-on-dielectric-based digital microfluidic chip with unique advantages for performing single-molecule detection. We illustrate how superparamagnetic particles can be printed with very high loading efficiency (over 98 %) and single-particle resolution in the microwell array patterned in the Teflon-AF ® surface of the grounding plate of the chip. Finally, the potential of the device for its application to single-molecule detection is demonstrated by the ultrasensitive detection of the biotinylated enzyme β-Galactosidase captured on streptavidin-coated particles in the described platform.

Single-particle aerosol mass spectrometry for the detection and identification of chemical warfare agent simulants.

PubMed

Martin, Audrey N; Farquar, George R; Frank, Matthias; Gard, Eric E; Fergenson, David P

2007-08-15

Single-particle aerosol mass spectrometry (SPAMS) was used for the real-time detection of liquid nerve agent simulants. A total of 1000 dual-polarity time-of-flight mass spectra were obtained for micrometer-sized single particles each of dimethyl methyl phosphonate, diethyl ethyl phosphonate, diethyl phosphoramidate, and diethyl phthalate using laser fluences between 0.58 and 7.83 nJ/microm2, and mass spectral variation with laser fluence was studied. The mass spectra obtained allowed identification of single particles of the chemical warfare agent (CWA) simulants at each laser fluence used although lower laser fluences allowed more facile identification. SPAMS is presented as a promising real-time detection system for the presence of CWAs.

Polymeric Materials With Additives for Durability and Radiation Shielding in Space

NASA Technical Reports Server (NTRS)

Kiefer, Richard

2011-01-01

Polymeric materials are attractive for use in space structures because of their light weight and high strength In addition, polymers are made of elements with low atomic numbers (Z), primarily carbon (C), hydrogen (H), oxygen (0), and nitrogen (N) which provide the best shielding from galactic cosmic rays (GCR) (ref. 1). Galactic cosmic rays are composed primarily of nuclei (i.e., fully ionized atoms) plus a contribution of about 2% from electrons and positrons. There is a small but significant component of GCR particles with high charge (Z > 10) and high energy (E >100 GeV) (ref. 2). These so-called HZE particles comprise only 1 to 2% of the cosmic ray fluence but they interact with very high specific ionization and contribute 50% of the long- term dose to humans. The best shield for this radiation would be liquid hydrogen, which is not feasible. For this reason, hydrogen-containing polymers make the most effective practical shields. Moreover, neutrons are formed in the interactions of GCR particles with materials. Neutrons can only lose energy by collisions or reactions with a nucleus since they are uncharged. This is a process that is much less probable than the Coulombic interactions of charged particles. Thus, neutrons migrate far from the site of the reaction in which they were formed. This increases the probability of neutrons reaching humans or electronic equipment. Fast neutrons (> 1 MeV) can interact with silicon chips in electronic equipment resulting in the production of recoil ions which can cause single event upsets (SEU) in sensitive components (ref. 3). Neutrons lose energy most effectively by elastic collisions with light atoms, particularly hydrogen atoms. Therefore, hydrogen-containing polymers are not only effective in interacting with GCR particles; they are also effective in reducing the energy of the neutrons formed in the interactions.

[The heavy ion irradiation influence on the thermodynamic parameters of liquids in human body].

PubMed

Vlasenko, T S; Bulavin, L A; Sysoev, V M

2014-01-01

In this manuscript a theoretical model describing the influence of the heavy ion radiotherapy on the liquid matter in the human body is suggested. Based on the fundamental equations of Bogoliubov chain the effective temperatures in the case of constant particles fluent are found in the context of single component model. An existence of such temperatures allows the use of equilibrium thermodynamics formalism to nonequilibrium stationary state. The obtained results provide the possibility of predicting the liquid matter structural changes in the biological systems in the area influenced by the heavy ion beams.

Cooling of a Bose-Einstein Condensate by Spin Distillation.

PubMed

Naylor, B; Maréchal, E; Huckans, J; Gorceix, O; Pedri, P; Vernac, L; Laburthe-Tolra, B

2015-12-11

We propose and experimentally demonstrate a new cooling mechanism leading to purification of a Bose-Einstein condensate (BEC). Our scheme starts with a BEC polarized in the lowest energy spin state. Spin excited states are thermally populated by lowering the single particle energy gap set by the magnetic field. Then, these spin-excited thermal components are filtered out, which leads to an increase of the BEC fraction. We experimentally demonstrate such cooling for a spin 3 ^{52}Cr dipolar BEC. Our scheme should be applicable to Na or Rb, with the perspective to reach temperatures below 1 nK.

SINGLE EVENT EFFECTS TEST FACILITY AT OAK RIDGE NATIONAL LABORATORY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riemer, Bernie; Gallmeier, Franz X; Dominik, Laura J

2015-01-01

Increasing use of microelectronics of ever diminishing feature size in avionics systems has led to a growing Single Event Effects (SEE) susceptibility arising from the highly ionizing interactions of cosmic rays and solar particles. Single event effects caused by atmospheric radiation have been recognized in recent years as a design issue for avionics equipment and systems. To ensure a system meets all its safety and reliability requirements, SEE induced upsets and potential system failures need to be considered, including testing of the components and systems in a neutron beam. Testing of ICs and systems for use in radiation environments requiresmore » the utilization of highly advanced laboratory facilities that can run evaluations on microcircuits for the effects of radiation. This paper provides a background of the atmospheric radiation phenomenon and the resulting single event effects, including single event upset (SEU) and latch up conditions. A study investigating requirements for future single event effect irradiation test facilities and developing options at the Spallation Neutron Source (SNS) is summarized. The relatively new SNS with its 1.0 GeV proton beam, typical operation of 5000 h per year, expertise in spallation neutron sources, user program infrastructure, and decades of useful life ahead is well suited for hosting a world-class SEE test facility in North America. Emphasis was put on testing of large avionics systems while still providing tunable high flux irradiation conditions for component tests. Makers of ground-based systems would also be served well by these facilities. Three options are described; the most capable, flexible, and highest-test-capacity option is a new stand-alone target station using about one kW of proton beam power on a gas-cooled tungsten target, with dual test enclosures. Less expensive options are also described.« less

Single Event Effects Test Facility Options at the Oak Ridge National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riemer, Bernie; Gallmeier, Franz X; Dominik, Laura J

2015-01-01

Increasing use of microelectronics of ever diminishing feature size in avionics systems has led to a growing Single Event Effects (SEE) susceptibility arising from the highly ionizing interactions of cosmic rays and solar particles. Single event effects caused by atmospheric radiation have been recognized in recent years as a design issue for avionics equipment and systems. To ensure a system meets all its safety and reliability requirements, SEE induced upsets and potential system failures need to be considered, including testing of the components and systems in a neutron beam. Testing of integrated circuits (ICs) and systems for use in radiationmore » environments requires the utilization of highly advanced laboratory facilities that can run evaluations on microcircuits for the effects of radiation. This paper provides a background of the atmospheric radiation phenomenon and the resulting single event effects, including single event upset (SEU) and latch up conditions. A study investigating requirements for future single event effect irradiation test facilities and developing options at the Spallation Neutron Source (SNS) is summarized. The relatively new SNS with its 1.0 GeV proton beam, typical operation of 5000 h per year, expertise in spallation neutron sources, user program infrastructure, and decades of useful life ahead is well suited for hosting a world-class SEE test facility in North America. Emphasis was put on testing of large avionics systems while still providing tunable high flux irradiation conditions for component tests. Makers of ground-based systems would also be served well by these facilities. Three options are described; the most capable, flexible, and highest-test-capacity option is a new stand-alone target station using about one kW of proton beam power on a gas-cooled tungsten target, with dual test enclosures. Less expensive options are also described.« less

Photocatalytic/Magnetic Composite Particles

NASA Technical Reports Server (NTRS)

Wu, Chang-Yu; Goswami, Yogi; Garretson, Charles; Andino, Jean; Mazyck, David

2007-01-01

Photocatalytic/magnetic composite particles have been invented as improved means of exploiting established methods of photocatalysis for removal of chemical and biological pollutants from air and water. The photocatalytic components of the composite particles are formulated for high levels of photocatalytic activity, while the magnetic components make it possible to control the movements of the particles through the application of magnetic fields. The combination of photocatalytic and magnetic properties can be exploited in designing improved air- and water treatment reactors.

Plant immune and growth receptors share common signalling components but localise to distinct plasma membrane nanodomains.

PubMed

Bücherl, Christoph A; Jarsch, Iris K; Schudoma, Christian; Segonzac, Cécile; Mbengue, Malick; Robatzek, Silke; MacLean, Daniel; Ott, Thomas; Zipfel, Cyril

2017-03-06

Cell surface receptors govern a multitude of signalling pathways in multicellular organisms. In plants, prominent examples are the receptor kinases FLS2 and BRI1, which activate immunity and steroid-mediated growth, respectively. Intriguingly, despite inducing distinct signalling outputs, both receptors employ common downstream signalling components, which exist in plasma membrane (PM)-localised protein complexes. An important question is thus how these receptor complexes maintain signalling specificity. Live-cell imaging revealed that FLS2 and BRI1 form PM nanoclusters. Using single-particle tracking we could discriminate both cluster populations and we observed spatiotemporal separation between immune and growth signalling platforms. This finding was confirmed by visualising FLS2 and BRI1 within distinct PM nanodomains marked by specific remorin proteins and differential co-localisation with the cytoskeleton. Our results thus suggest that signalling specificity between these pathways may be explained by the spatial separation of FLS2 and BRI1 with their associated signalling components within dedicated PM nanodomains.

An investigation of enhanced capability thermal barrier coating systems for diesel engine components

NASA Technical Reports Server (NTRS)

Holtzman, R. L.; Layne, J. L.; Schechter, B.

1984-01-01

Material systems and processes for the development of effective and durable thermal barriers for heavy duty diesel engines were investigated. Seven coating systems were evaluated for thermal conductivity, erosion resistance, corrosion/oxidation resistance, and thermal shock resistance. An advanced coating system based on plasma sprayed particle yttria stabilized zirconia (PS/HYSZ) was judged superior in these tests. The measured thermal conductivity of the selected coating was 0.893 W/m C at 371 C. The PS/HYSZ coating system was applied to the piston crown, fire deck and valves of a single cylinder low heat rejection diesel engine. The coated engine components were tested for 24 hr at power levels from 0.83 MPa to 1.17 MPa brake mean effective pressure. The component coatings survived the engine tests with a minimum of distress. The measured fire deck temperatures decreased 86 C (155 F) on the intake side and 42 C (75 F) on the exhaust side with the coating applied.

An Exact Separation of the Spin-Free and Spin-Dependent Terms of the Dirac-Coulomb-Breit Hamiltonian

NASA Technical Reports Server (NTRS)

Dyall, Kenneth G.

1994-01-01

The Dirac Hamiltonian is transformed by extracting the operator (sigma x p)/2mc from the small component of the wave function and applying it to the operators of the original Hamiltonian. The resultant operators contain products of Paull matrices that can be rearranged to give spin-free and spin-dependent operators. These operators are the ones encountered in the Breit-Pauli Hamiltonian, as well as some of higher order in alpha(sup 2). However, since the transformation of the original Dirac Hamiltonian is exact, the new Hamiltonian can be used in variational calculations, with or without the spin-dependent terms. The new small component functions have the same symmetry properties as the large component. Use of only the spin-free terms of the new Hamiltonian permits the same factorization over spin variables as in nonrelativistic theory, and therefore all the post-Self-Consistent Field (SCF) machinery of nonrelativistic calculations can be applied. However, the single-particle functions are two-component orbitals having a large and small component, and the SCF methods must be modified accordingly. Numerical examples are presented, and comparisons are made with the spin-free second-order Douglas-Kroll transformed Hamiltonian of Hess.

Impact of Measurement Uncertainties on Receptor Modeling of Speciated Atmospheric Mercury.

PubMed

Cheng, I; Zhang, L; Xu, X

2016-02-09

Gaseous oxidized mercury (GOM) and particle-bound mercury (PBM) measurement uncertainties could potentially affect the analysis and modeling of atmospheric mercury. This study investigated the impact of GOM measurement uncertainties on Principal Components Analysis (PCA), Absolute Principal Component Scores (APCS), and Concentration-Weighted Trajectory (CWT) receptor modeling results. The atmospheric mercury data input into these receptor models were modified by combining GOM and PBM into a single reactive mercury (RM) parameter and excluding low GOM measurements to improve the data quality. PCA and APCS results derived from RM or excluding low GOM measurements were similar to those in previous studies, except for a non-unique component and an additional component extracted from the RM dataset. The percent variance explained by the major components from a previous study differed slightly compared to RM and excluding low GOM measurements. CWT results were more sensitive to the input of RM than GOM excluding low measurements. Larger discrepancies were found between RM and GOM source regions than those between RM and PBM. Depending on the season, CWT source regions of RM differed by 40-61% compared to GOM from a previous study. No improvement in correlations between CWT results and anthropogenic mercury emissions were found.

Impact of Measurement Uncertainties on Receptor Modeling of Speciated Atmospheric Mercury

PubMed Central

Cheng, I.; Zhang, L.; Xu, X.

2016-01-01

Gaseous oxidized mercury (GOM) and particle-bound mercury (PBM) measurement uncertainties could potentially affect the analysis and modeling of atmospheric mercury. This study investigated the impact of GOM measurement uncertainties on Principal Components Analysis (PCA), Absolute Principal Component Scores (APCS), and Concentration-Weighted Trajectory (CWT) receptor modeling results. The atmospheric mercury data input into these receptor models were modified by combining GOM and PBM into a single reactive mercury (RM) parameter and excluding low GOM measurements to improve the data quality. PCA and APCS results derived from RM or excluding low GOM measurements were similar to those in previous studies, except for a non-unique component and an additional component extracted from the RM dataset. The percent variance explained by the major components from a previous study differed slightly compared to RM and excluding low GOM measurements. CWT results were more sensitive to the input of RM than GOM excluding low measurements. Larger discrepancies were found between RM and GOM source regions than those between RM and PBM. Depending on the season, CWT source regions of RM differed by 40–61% compared to GOM from a previous study. No improvement in correlations between CWT results and anthropogenic mercury emissions were found. PMID:26857835

Measurements of the evaporation and hygroscopic response of single fine-mode aerosol particles using a Bessel beam optical trap.

PubMed

Cotterell, Michael I; Mason, Bernard J; Carruthers, Antonia E; Walker, Jim S; Orr-Ewing, Andrew J; Reid, Jonathan P

2014-02-07

A single horizontally-propagating zeroth order Bessel laser beam with a counter-propagating gas flow was used to confine single fine-mode aerosol particles over extended periods of time, during which process measurements were performed. Particle sizes were measured by the analysis of the angular variation of light scattered at 532 nm by a particle in the Bessel beam, using either a probe beam at 405 nm or 633 nm. The vapour pressures of glycerol and 1,2,6-hexanetriol particles were determined to be 7.5 ± 2.6 mPa and 0.20 ± 0.02 mPa respectively. The lower volatility of hexanetriol allowed better definition of the trapping environment relative humidity profile over the measurement time period, thus higher precision measurements were obtained compared to those for glycerol. The size evolution of a hexanetriol particle, as well as its refractive index at wavelengths 532 nm and 405 nm, were determined by modelling its position along the Bessel beam propagation length while collecting phase functions with the 405 nm probe beam. Measurements of the hygroscopic growth of sodium chloride and ammonium sulfate have been performed on particles as small as 350 nm in radius, with growth curves well described by widely used equilibrium state models. These are the smallest particles for which single-particle hygroscopicity has been measured and represent the first measurements of hygroscopicity on fine mode and near-accumulation mode aerosols, the size regimes bearing the most atmospheric relevance in terms of loading, light extinction and scattering. Finally, the technique is contrasted with other single particle and ensemble methods, and limitations are assessed.

High-resolution noise substitution to measure overfitting and validate resolution in 3D structure determination by single particle electron cryomicroscopy.

PubMed

Chen, Shaoxia; McMullan, Greg; Faruqi, Abdul R; Murshudov, Garib N; Short, Judith M; Scheres, Sjors H W; Henderson, Richard

2013-12-01

Three-dimensional (3D) structure determination by single particle electron cryomicroscopy (cryoEM) involves the calculation of an initial 3D model, followed by extensive iterative improvement of the orientation determination of the individual particle images and the resulting 3D map. Because there is much more noise than signal at high resolution in the images, this creates the possibility of noise reinforcement in the 3D map, which can give a false impression of the resolution attained. The balance between signal and noise in the final map at its limiting resolution depends on the image processing procedure and is not easily predicted. There is a growing awareness in the cryoEM community of how to avoid such over-fitting and over-estimation of resolution. Equally, there has been a reluctance to use the two principal methods of avoidance because they give lower resolution estimates, which some people believe are too pessimistic. Here we describe a simple test that is compatible with any image processing protocol. The test allows measurement of the amount of signal and the amount of noise from overfitting that is present in the final 3D map. We have applied the method to two different sets of cryoEM images of the enzyme beta-galactosidase using several image processing packages. Our procedure involves substituting the Fourier components of the initial particle image stack beyond a chosen resolution by either the Fourier components from an adjacent area of background, or by simple randomisation of the phases of the particle structure factors. This substituted noise thus has the same spectral power distribution as the original data. Comparison of the Fourier Shell Correlation (FSC) plots from the 3D map obtained using the experimental data with that from the same data with high-resolution noise (HR-noise) substituted allows an unambiguous measurement of the amount of overfitting and an accompanying resolution assessment. A simple formula can be used to calculate an unbiased FSC from the two curves, even when a substantial amount of overfitting is present. The approach is software independent. The user is therefore completely free to use any established method or novel combination of methods, provided the HR-noise test is carried out in parallel. Applying this procedure to cryoEM images of beta-galactosidase shows how overfitting varies greatly depending on the procedure, but in the best case shows no overfitting and a resolution of ~6 Å. (382 words). © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Comparison of particle sizes between 238PuO 2 before aqueous processing, after aqueous processing, and after ball milling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mulford, Roberta Nancy

Particle sizes determined for a single lot of incoming Russian fuel and for a lot of fuel after aqueous processing are compared with particle sizes measured on fuel after ball-milling. The single samples of each type are believed to have particle size distributions typical of oxide from similar lots, as the processing of fuel lots is fairly uniform. Variation between lots is, as yet, uncharacterized. Sampling and particle size measurement methods are discussed elsewhere.

Portraits of colloidal hybrid nanostructures: controlled synthesis and potential applications.

PubMed

Nguyen, Thanh-Dinh

2013-03-01

Inorganic hybrid nanostructures containing two or more nanocomponents have been emerging in many areas of materials science in recent years. The particle-particle interactions in a hybrid particle system could significantly improve existing local electronic structure and induce tunable physiochemical responses. The current work reviews the diverse inorganic hybrid nanostructures formed by adhesion of the different single components via seed-mediated method. The hybrid nanomaterials have great potentials for real applications in many other fields. The nanohybrids have been used as efficient heterocatalysts for carbon monoxide conversion and photodegradation of organic contaminants. The enhanced catalytic activity of these hybrid nanocatalysts could be attributed the formation of oxygen vacancies and electron transfer across the structural junction in a hybrid system as a result of the interfacial particle-particle interactions. The synergistic combination of up-converting and semiconducting properties in an up-converting semiconducting hybrid particle results in appearance of sub-band-gap photoconductivity. This behavior has a great significance for the design of photovoltaic devices for effective solar energy conversion. The functionalization and subsequent bioconjugation of the hybrid nanostructures to afford the multifunctional nanomedical platforms for simultaneous diagnosis and therapy are reviewed. The conjugated multifunctional hybrid nanostructures exhibit high biocompatibility and highly selective binding with functional groups-fabricated alive organs through delivering them to the tumor sites. The clever combinations of multifunctional features and antibody conjugation within these vehicles make them to generally offer new opportunities for clinical diagnostics and therapeutics. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Fabrication of a single sub-micron pore spanning a single crystal (100) diamond membrane and impact on particle translocation [Particle translocation through a single crystal diamond pore fabricated by electron beam induced chemical etching

DOE PAGES

Webb, Jennifer R.; Martin, Aiden A.; Johnson, Robert P.; ...

2017-06-21

The fabrication of sub-micron pores in single crystal diamond membranes, which span the entirety of the membrane, is described for the first time, and the translocation properties of polymeric particles through the pore investigated. The pores are produced using a combination of laser micromachining to form the membrane and electron beam induced etching to form the pore. Single crystal diamond as the membrane material, has the advantages of chemical stability and durability, does not hydrate and swell, has outstanding electrical properties that facilitate fast, low noise current-time measurements and is optically transparent for combined optical-conductance sensing. The resulting pores aremore » characterized individually using both conductance measurements, employing a microcapillary electrochemical setup, and electron microscopy. Proof-of-concept experiments to sense charged polystyrene particles as they are electrophoretically driven through a single diamond pore are performed, and the impact of this new pore material on particle translocation is explored. As a result, these findings reveal the potential of diamond as a platform for pore-based sensing technologies and pave the way for the fabrication of single nanopores which span the entirety of a diamond membrane.« less

Fabrication of a single sub-micron pore spanning a single crystal (100) diamond membrane and impact on particle translocation [Particle translocation through a single crystal diamond pore fabricated by electron beam induced chemical etching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Webb, Jennifer R.; Martin, Aiden A.; Johnson, Robert P.

The fabrication of sub-micron pores in single crystal diamond membranes, which span the entirety of the membrane, is described for the first time, and the translocation properties of polymeric particles through the pore investigated. The pores are produced using a combination of laser micromachining to form the membrane and electron beam induced etching to form the pore. Single crystal diamond as the membrane material, has the advantages of chemical stability and durability, does not hydrate and swell, has outstanding electrical properties that facilitate fast, low noise current-time measurements and is optically transparent for combined optical-conductance sensing. The resulting pores aremore » characterized individually using both conductance measurements, employing a microcapillary electrochemical setup, and electron microscopy. Proof-of-concept experiments to sense charged polystyrene particles as they are electrophoretically driven through a single diamond pore are performed, and the impact of this new pore material on particle translocation is explored. As a result, these findings reveal the potential of diamond as a platform for pore-based sensing technologies and pave the way for the fabrication of single nanopores which span the entirety of a diamond membrane.« less

Dependence of Aerosol Light Absorption and Single-Scattering Albedo On Ambient Relative Humidity for Sulfate Aerosols with Black Carbon Cores

NASA Technical Reports Server (NTRS)

Redemann, Jens; Russell, Philip B.; Hamill, Patrick

2001-01-01

Atmospheric aerosols frequently contain hygroscopic sulfate species and black carbon (soot) inclusions. In this paper we report results of a modeling study to determine the change in aerosol absorption due to increases in ambient relative humidity (RH), for three common sulfate species, assuming that the soot mass fraction is present as a single concentric core within each particle. Because of the lack of detailed knowledge about various input parameters to models describing internally mixed aerosol particle optics, we focus on results that were aimed at determining the maximum effect that particle humidification may have on aerosol light absorption. In the wavelength range from 450 to 750 nm, maximum absorption humidification factors (ratio of wet to 'dry=30% RH' absorption) for single aerosol particles are found to be as large as 1.75 when the RH changes from 30 to 99.5%. Upon lesser humidification from 30 to 80% RH, absorption humidification for single particles is only as much as 1.2, even for the most favorable combination of initial ('dry') soot mass fraction and particle size. Integrated over monomodal lognormal particle size distributions, maximum absorption humidification factors range between 1.07 and 1.15 for humidification from 30 to 80% and between 1.1 and 1.35 for humidification from 30 to 95% RH for all species considered. The largest humidification factors at a wavelength of 450 nm are obtained for 'dry' particle size distributions that peak at a radius of 0.05 microns, while the absorption humidification factors at 700 nm are largest for 'dry' size distributions that are dominated by particles in the radius range of 0.06 to 0.08 microns. Single-scattering albedo estimates at ambient conditions are often based on absorption measurements at low RH (approx. 30%) and the assumption that aerosol absorption does not change upon humidification (i.e., absorption humidification equal to unity). Our modeling study suggests that this assumption alone can introduce absolute errors in estimates of the midvisible single-scattering albedo of up to 0.05 for realistic dry particle size distributions. Our study also indicates that this error increases with increasing wavelength. The potential errors in aerosol single-scattering albedo derived here are comparable in magnitude and in addition to uncertainties in single-scattering albedo estimates that are based on measurements of aerosol light absorption and scattering.

Brown Carbon Production in Ammonium- or Amine-Containing Aerosol Particles by Reactive Uptake of Methylglyoxal and Photolytic Cloud Cycling.

PubMed

De Haan, David O; Hawkins, Lelia N; Welsh, Hannah G; Pednekar, Raunak; Casar, Jason R; Pennington, Elyse A; de Loera, Alexia; Jimenez, Natalie G; Symons, Michael A; Zauscher, Melanie; Pajunoja, Aki; Caponi, Lorenzo; Cazaunau, Mathieu; Formenti, Paola; Gratien, Aline; Pangui, Edouard; Doussin, Jean-François

2017-07-05

The effects of methylglyoxal uptake on the physical and optical properties of aerosol containing amines or ammonium sulfate were determined before and after cloud processing in a temperature- and RH-controlled chamber. The formation of brown carbon was observed upon methylglyoxal addition, detected as an increase in water-soluble organic carbon mass absorption coefficients below 370 nm and as a drop in single-scattering albedo at 450 nm. The imaginary refractive index component k 450 reached a maximum value of 0.03 ± 0.009 with aqueous glycine aerosol particles. Browning of solid particles occurred at rates limited by chamber mixing (<1 min), and in liquid particles occurred more gradually, but in all cases occurred much more rapidly than in bulk aqueous studies. Further browning in AS and methylammonium sulfate seeds was triggered by cloud events with chamber lights on, suggesting photosensitized brown carbon formation. Despite these changes in optical aerosol characteristics, increases in dried aerosol mass were rarely observed (<1 μg/m 3 in all cases), consistent with previous experiments on methylglyoxal. Under dry, particle-free conditions, methylglyoxal reacted (presumably on chamber walls) with methylamine with a rate constant k = (9 ± 2) × 10 -17 cm 3 molecule -1 s -1 at 294 K and activation energy E a = 64 ± 37 kJ/mol.

TAKASAGO-6 apparatus for cryogenic coherent X-ray diffraction imaging of biological non-crystalline particles using X-ray free electron laser at SACLA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobayashi, Amane; Sekiguchi, Yuki; Oroguchi, Tomotaka

Coherent X-ray diffraction imaging (CXDI) is a technique for structure analyses of non-crystalline particles with dimensions ranging from micrometer to sub-micrometer. We have developed a diffraction apparatus named TAKASAGO-6 for use in single-shot CXDI experiments of frozen-hydrated non-crystalline biological particles at cryogenic temperature with X-ray free electron laser pulses provided at a repetition rate of 30 Hz from the SPring-8 Angstrom Compact free-electron LAser. Specimen particles are flash-cooled after being dispersed on thin membranes supported by specially designed disks. The apparatus is equipped with a high-speed translation stage with a cryogenic pot for raster-scanning of the disks at a speedmore » higher than 25 μm/33 ms. In addition, we use devices assisting the easy transfer of cooled specimens from liquid-nitrogen storages to the cryogenic pot. In the current experimental procedure, more than 20 000 diffraction patterns can be collected within 1 h. Here we report the key components and performance of the diffraction apparatus. Based on the efficiency of the diffraction data collection and the structure analyses of metal particles, biological cells, and cellular organelles, we discuss the future application of this diffraction apparatus for structure analyses of biological specimens.« less

Optimal noise reduction in 3D reconstructions of single particles using a volume-normalized filter

PubMed Central

Sindelar, Charles V.; Grigorieff, Nikolaus

2012-01-01

The high noise level found in single-particle electron cryo-microscopy (cryo-EM) image data presents a special challenge for three-dimensional (3D) reconstruction of the imaged molecules. The spectral signal-to-noise ratio (SSNR) and related Fourier shell correlation (FSC) functions are commonly used to assess and mitigate the noise-generated error in the reconstruction. Calculation of the SSNR and FSC usually includes the noise in the solvent region surrounding the particle and therefore does not accurately reflect the signal in the particle density itself. Here we show that the SSNR in a reconstructed 3D particle map is linearly proportional to the fractional volume occupied by the particle. Using this relationship, we devise a novel filter (the “single-particle Wiener filter”) to minimize the error in a reconstructed particle map, if the particle volume is known. Moreover, we show how to approximate this filter even when the volume of the particle is not known, by optimizing the signal within a representative interior region of the particle. We show that the new filter improves on previously proposed error-reduction schemes, including the conventional Wiener filter as well as figure-of-merit weighting, and quantify the relationship between all of these methods by theoretical analysis as well as numeric evaluation of both simulated and experimentally collected data. The single-particle Wiener filter is applicable across a broad range of existing 3D reconstruction techniques, but is particularly well suited to the Fourier inversion method, leading to an efficient and accurate implementation. PMID:22613568

Protective effects of pulmonary epithelial lining fluid on oxidative stress and DNA single-strand breaks caused by ultrafine carbon black, ferrous sulphate and organic extract of diesel exhaust particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chuang, Hsiao-Chi; Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan; Cheng, Yi-Ling

Pulmonary epithelial lining fluid (ELF) is the first substance to make contact with inhaled particulate matter (PM) and interacts chemically with PM components. The objective of this study was to determine the role of ELF in oxidative stress, DNA damage and the production of proinflammatory cytokines following physicochemical exposure to PM. Ultrafine carbon black (ufCB, 15 nm; a model carbonaceous core), ferrous sulphate (FeSO{sub 4}; a model transition metal) and a diesel exhaust particle (DEP) extract (a model organic compound) were used to examine the acellular oxidative potential of synthetic ELF and non-ELF systems. We compared the effects of exposuremore » to ufCB, FeSO{sub 4} and DEP extract on human alveolar epithelial Type II (A549) cells to determine the levels of oxidative stress, DNA single-strand breaks and interleukin-8 (IL-8) production in ELF and non-ELF systems. The effects of ufCB and FeSO{sub 4} on the acellular oxidative potential, cellular oxidative stress and DNA single-strand breakage were mitigated significantly by the addition of ELF, whereas there was no decrease following treatment with the DEP extract. There was no significant effect on IL-8 production following exposure to samples that were suspended in ELF/non-ELF systems. The results of the present study indicate that ELF plays an important role in the initial defence against PM in the pulmonary environment. Experimental components, such as ufCB and FeSO{sub 4}, induced the production of oxidative stress and led to DNA single-strand breaks, which were moderately prevented by the addition of ELF. These findings suggest that ELF plays a protective role against PM-driven oxidative stress and DNA damage. -- Highlights: ► To determine the role of ELF in ROS, DNA damage and IL-8 after exposure to PM. ► ufCB, FeSO{sub 4} and DEP extract were used to examine the protective effects of ELF. ► PM-driven oxidative stress and DNA single-strand breakage were mitigated by ELF. ► The findings suggest that ELF has a protective role against PM. ► The synthetic ELF system could reduce the use of animals in PM-driven ROS testing.« less

Two component Feebly Interacting Massive Particle (FIMP) dark matter

NASA Astrophysics Data System (ADS)

Pandey, Madhurima; Majumdar, Debasish; Prasad Modak, Kamakshya

2018-06-01

We explore the idea of an alternative candidate for particle dark matter namely Feebly Interacting Massive Particle (FIMP) in the framework of a two component singlet scalar model. Singlet scalar dark matter has already been demonstrated to be a viable candidate for WIMP (Weakly Interacting Massive Particle) dark matter in literature. In the FIMP scenario, dark matter particles are slowly produced via "thermal freeze-in" mechanism in the early Universe and are never abundant enough to reach thermal equilibrium or to undergo pair annihilation inside the Universe's plasma due to their extremely small couplings. We demonstrate that for smaller couplings too, required for freeze-in process, a two component scalar dark matter model considered here could well be a viable candidate for FIMP . In this scenario, the Standard Model of particle physics is extended by two gauge singlet real scalars whose stability is protected by an unbroken Z2× Z'2 symmetry and they are assumed to acquire no VEV after Spontaneous Symmetry Breaking. We explore the viable mass regions in the present two scalar DM model that is in accordance with the FIMP scenario. We also explore the upper limits of masses of the two components from the consideration of their self interactions.

Cirrus Parcel Model Comparison Project. Phase 1: The Critical Components to Simulate Cirrus Initiation Explicitly.

NASA Astrophysics Data System (ADS)

Lin, Ruei-Fong; O'C. Starr, David; Demott, Paul J.; Cotton, Richard; Sassen, Kenneth; Jensen, Eric; Kärcher, Bernd; Liu, Xiaohong

2002-08-01

The Cirrus Parcel Model Comparison Project, a project of the GCSS [Global Energy and Water Cycle Experiment (GEWEX) Cloud System Studies] Working Group on Cirrus Cloud Systems, involves the systematic comparison of current models of ice crystal nucleation and growth for specified, typical, cirrus cloud environments. In Phase 1 of the project reported here, simulated cirrus cloud microphysical properties from seven models are compared for `warm' (40°C) and `cold' (60°C) cirrus, each subject to updrafts of 0.04, 0.2, and 1 m s1. The models employ explicit microphysical schemes wherein the size distribution of each class of particles (aerosols and ice crystals) is resolved into bins or the evolution of each individual particle is traced. Simulations are made including both homogeneous and heterogeneous ice nucleation mechanisms (all-mode simulations). A single initial aerosol population of sulfuric acid particles is prescribed for all simulations. Heterogeneous nucleation is disabled for a second parallel set of simulations in order to isolate the treatment of the homogeneous freezing (of haze droplets) nucleation process. Analysis of these latter simulations is the primary focus of this paper.Qualitative agreement is found for the homogeneous-nucleation-only simulations; for example, the number density of nucleated ice crystals increases with the strength of the prescribed updraft. However, significant quantitative differences are found. Detailed analysis reveals that the homogeneous nucleation rate, haze particle solution concentration, and water vapor uptake rate by ice crystal growth (particularly as controlled by the deposition coefficient) are critical components that lead to differences in the predicted microphysics.Systematic differences exist between results based on a modified classical theory approach and models using an effective freezing temperature approach to the treatment of nucleation. Each method is constrained by critical freezing data from laboratory studies, but each includes assumptions that can only be justified by further laboratory research. Consequently, it is not yet clear if the two approaches can be made consistent. Large haze particles may deviate considerably from equilibrium size in moderate to strong updrafts (0.2-1 m s1) at 60°C. The equilibrium assumption is commonly invoked in cirrus parcel models. The resulting difference in particle-size-dependent solution concentration of haze particles may significantly affect the ice particle formation rate during the initial nucleation interval. The uptake rate for water vapor excess by ice crystals is another key component regulating the total number of nucleated ice crystals. This rate, the product of particle number concentration and ice crystal diffusional growth rate, which is particularly sensitive to the deposition coefficient when ice particles are small, modulates the peak particle formation rate achieved in an air parcel and the duration of the active nucleation time period. The consequent differences in cloud microphysical properties, and thus cloud optical properties, between state-of-the-art models of ice crystal initiation are significant.Intermodel differences in the case of all-mode simulations are correspondingly greater than in the case of homogeneous nucleation acting alone. Definitive laboratory and atmospheric benchmark data are needed to improve the treatment of heterogeneous nucleation processes.

New instrument for tribocharge measurement due to single particle impacts.

PubMed

Watanabe, Hideo; Ghadiri, Mojtaba; Matsuyama, Tatsushi; Ding, Yu Long; Pitt, Kendal G

2007-02-01

During particulate solid processing, particle-particle and particle-wall collisions can generate electrostatic charges. This may lead to a variety of problems ranging from fire and explosion hazards to segregation, caking, and blocking. A fundamental understanding of the particle charging in such situations is therefore essential. For this purpose we have developed a new device that can measure charge transfer due to impact between a single particle and a metal plate. The device consists of an impact test system and two sets of Faraday cage and preamplifier for charge measurement. With current amplifiers, high-resolution measurements of particle charges of approximately 1 and 10 fC have been achieved before and after the impact, respectively. The device allows charge measurements of single particles with a size as small as approximately 100 microm impacting on the target at different incident angles with a velocity up to about 80 m/s. Further analyses of the charge transfer as a function of particle initial charge define an equilibrium charge, i.e., an initial charge level prior to impact for which no net charge transfer would occur as a result of impact.

New instrument for tribocharge measurement due to single particle impacts

NASA Astrophysics Data System (ADS)

Watanabe, Hideo; Ghadiri, Mojtaba; Matsuyama, Tatsushi; Long Ding, Yu; Pitt, Kendal G.

2007-02-01

During particulate solid processing, particle-particle and particle-wall collisions can generate electrostatic charges. This may lead to a variety of problems ranging from fire and explosion hazards to segregation, caking, and blocking. A fundamental understanding of the particle charging in such situations is therefore essential. For this purpose we have developed a new device that can measure charge transfer due to impact between a single particle and a metal plate. The device consists of an impact test system and two sets of Faraday cage and preamplifier for charge measurement. With current amplifiers, high-resolution measurements of particle charges of approximately 1 and 10fC have been achieved before and after the impact, respectively. The device allows charge measurements of single particles with a size as small as ˜100μm impacting on the target at different incident angles with a velocity up to about 80m/s. Further analyses of the charge transfer as a function of particle initial charge define an equilibrium charge, i.e., an initial charge level prior to impact for which no net charge transfer would occur as a result of impact.

Hygroscopicity Behavior, Activation Properties and Chemical Composition of Atmospheric Aerosol at a Background Site in the Megacity Region of Peking

NASA Astrophysics Data System (ADS)

Henning, Silvia; Nowak, Andreas; Mildenberger, Katrin; Göbel, Tina; Nekat, Bettina; van Pinxteren, Dominik; Herrmann, Hartmut; Zhao, Chunsheng; Wiedensohler, Alfred; Stratmann, Frank

2010-05-01

Large areas of China suffer from heavy air pollution (both gaseous and particulate) caused by strong economic growth in the last two decades. However, knowledge concerning the physical and chemical properties of the resulting aerosol particles populations, and their effects on the optical properties of the atmosphere, is still sparse. In the framework of the investigations presented here, comprehensive measurements concerning aerosol particle hygroscopicity, CCN ability, composition, and optical properties were performed. The investigations are part of the DFG-funded project HaChi (Haze in China) and are conducted in collaboration with the Peking University. A conclusive parameterization of aerosol hygroscopicity and activation data is aimed for, which will then be implemented in a meso-scale model to investigate aerosol-cloud-radiation and precipitation interactions. During two intensive measurements campaigns (March 2009 and July/ August 2009), in-situ aerosol measurements have been performed in an air-conditioned mobile laboratory next to the Wuqing Meteorological Station (39°23'8.53"N, 117°1'25.88"E), which is located between Bejing and Tijanjin and is thereby an ideal background site in a megacity region. The particle number size distribution (TDMPS), the particle optical properties (MAAP and nephelometer) and their hygroscopic properties at high RH (HH-TDMA, LACIS-mobile) were characterized as well as their cloud nucleating properties above supersaturation (DMT-CCNC). 24 h PM1 particle samples were continuously collected over the two campaigns in winter and summer using a DIGITEL high volume sampler (DHA-80). Additionally two 6h size-resolved samples (daytime and night-time) were collected each day applying an 11-stage Berner impactor. The size-selection of HH-TDMA, LACIS and the CCNC was synchronized with the Berner stages. Opening analysis of the winter campaign data showed that the HH-TDMA usually detected a hydrophobic and a hygroscopic mode, i.e., the particles were externally mixed. On average the growth factor in the hydrophobic mode was about 1.1 (200nm @ 98.5%). 12% of the particles were of hydrophobic nature for 200 nm and 15% over all sizes. LACIS-mobile focused on the hygroscopic mode, as this mode is mainly responsible for the optical properties of the atmosphere at high RHs. During the whole campaign very high growth factors (GFmedian = 3.56, 200 nm @ 99.2%) were observed, close to those of ammonium sulfate, with only slight dependence on the air mass. The analysis of the DIGITEL samples showed that the main components of PM1 are inorganic ions like the secondary formed ammonium nitrate und ammonium sulphate, as well as carbonaceous material. The organic carbon fraction is mostly dominated by water soluble organic carbon (80% in average) and was more analyzed in more detail for dicarboxylic acids, fatty acids, sugars and sugar related compounds. High concentrations of tracers like the anhydrosugar levoglucosan suggest biomass burning emissions as a dominant source of organic particles in the area. Closure between hygroscopic growth, CCN activation and chemical composition is aimed for with two different approaches: a) one single-parameter Köhler model applying the hygroscopicity parameter kappa following [Petters and Kreidenweis, 2007] and b) a standard Köhler model using as input parameter 4 major chemical components as analyzed from the DIGITEL samples. First tests for 200 nm particles showed very good agreement for the kappa-approach between measured and predicted critical activation. In the second approach the mass of 4 major components, namely ammonium sulfate, ammonium nitrate, sodium chloride and soluble organic mater were used as input parameter of a standard Köhler model including an insoluble core. Here the hygroscopic growth factor was underestimated, but the activation point was predicted well. Petters, M. D., and S. M. Kreidenweis (2007), A single parameter representation of hygroscopic growth and cloud condensation nucleus activity, Atmospheric Chemistry and Physics, 7, 1961-1971.

Development of Magnetic Nanomaterials and Devices for Biological Applications

DTIC Science & Technology

2007-10-30

analysis. Suitable crystals for the X-ray diffraction analysis were grown as dark red plates from a saturated hexane solution of [ Co3 (CO)9CCH3] at 4 ºC...Commercially available magnetic nanoparticles are suitable for cell separation where a large number of particles are used to separate a single cell...from a sample. The magnetic moment of these particles is not high enough to enable the separation of single antigen molecules using a single particle

On-Chip Magnetic Platform for Single-Particle Manipulation with Integrated Electrical Feedback.

PubMed

Monticelli, Marco; Torti, Andrea; Cantoni, Matteo; Petti, Daniela; Albisetti, Edoardo; Manzin, Alessandra; Guerriero, Erica; Sordan, Roman; Gervasoni, Giacomo; Carminati, Marco; Ferrari, Giorgio; Sampietro, Marco; Bertacco, Riccardo

2016-02-17

Methods for the manipulation of single magnetic particles have become very interesting, in particular for in vitro biological studies. Most of these studies require an external microscope to provide the operator with feedback for controlling the particle motion, thus preventing the use of magnetic particles in high-throughput experiments. In this paper, a simple and compact system with integrated electrical feedback is presented, implementing in the very same device both the manipulation and detection of the transit of single particles. The proposed platform is based on zig-zag shaped magnetic nanostructures, where transverse magnetic domain walls are pinned at the corners and attract magnetic particles in suspension. By applying suitable external magnetic fields, the domain walls move to the nearest corner, thus causing the step by step displacement of the particles along the nanostructure. The very same structure is also employed for detecting the bead transit. Indeed, the presence of the magnetic particle in suspension over the domain wall affects the depinning field required for its displacement. This characteristic field can be monitored through anisotropic magnetoresistance measurements, thus implementing an integrated electrical feedback of the bead transit. In particular, the individual manipulation and detection of single 1-μm sized beads is demonstrated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High efficiency virtual impactor

DOEpatents

Loo, B.W.

1980-03-27

Environmental monitoring of atmospheric air is facilitated by a single stage virtual impactor for separating an inlet flow (Q/sub 0/) having particulate contaminants into a coarse particle flow (Q/sub 1/) and a fine particle flow (Q/sub 2/) to enable collection of such particles on different filters for separate analysis. An inlet particle acceleration nozzle and coarse particle collection probe member having a virtual impaction opening are aligned along a single axis and spaced apart to define a flow separation region at which the fine particle flow (Q/sub 2/) is drawn radially outward into a chamber while the coarse particle flow (Q/sub 1/) enters the virtual impaction opening.

The Scattering Properties of Natural Terrestrial Snows versus Icy Satellite Surfaces

NASA Technical Reports Server (NTRS)

Domingue, Deborah; Hartman, Beth; Verbiscer, Anne

1997-01-01

Our comparisons of the single particle scattering behavior of terrestrial snows and icy satellite regoliths to the laboratory particle scattering measurements of McGuire and Hapke demonstrate that the differences between icy satellite regoliths and their terrestrial counterparts are due to particle structures and textures. Terrestrial snow particle structures define a region in the single particle scattering function parameter space separate from the regions defined by the McGuire and Hapke artificial laboratory particles. The particle structures and textures of the grains composing icy satellites regoliths are not simple or uniform but consist of a variety of particle structure and texture types, some of which may be a combination of the particle types investigated by McGuire and Hapke.

Silver transfer in proustite Ag{sub 3}AsS{sub 3} at high temperatures: Conductivity and single-crystal X-ray studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gagor, Anna; Pawlowski, Antoni; Pietraszko, Adam

2009-03-15

Single crystals of proustite Ag{sub 3}AsS{sub 3} have been characterised by impedance spectroscopy and single-crystal X-ray diffraction in the temperature ranges of 295-543 and 295-695 K, respectively. An analysis of the one-particle potential of silver atoms shows that in the whole measuring temperature range defects in the silver substructure play a major role in the conduction mechanism. Furthermore, the silver transfer is equally probable within silver chains and spirals, as well as between chains and spirals. The trigonal R3c room temperature phase does not change until the decomposition of the crystal. The electric anomaly of the first-order character which appearsmore » near 502 K is related to an increase in the electronic component of the total conductivity resulting from Ag{sub 2}S deposition at the sample surface. - Joint probability density function map of silver atoms at T=695 K.« less

Precipitation Behaviors of TiN Inclusion in GCr15 Bearing Steel Billet

NASA Astrophysics Data System (ADS)

Tian, Qianren; Wang, Guocheng; Zhao, Yang; Li, Jing; Wang, Qi

2018-06-01

There are many types of non-metallic TiN-based inclusions observed in GCr15 bearing steel, including single-particle TiN, multi-particle polymerized TiN, and complex inclusions like TiN-MnS, TiN-MgO-MgAl2O4 (TiN-MgO-MA), and TiN-MgAl2O4-MnS (TiN-MA-MnS). Thermodynamic calculations suggest that single-particle TiN precipitates dominate the mushy zone of GCr15 bearing steel. Kinetic calculations regarding TiN growth suggest that the final size of the single-particle TiN ranges between 1 and 6 μm in the initial concentration range of [pct Ti] = 0.0060 to 0.0079 and [pct N] = 0.0049 to 0.0070, at 1620 to 1640 K and a local cooling rate of 0.5 to 10 K/s. The multi-particle polymerized TiN are formed by single TiN particles in three stages: single-particle TiN inclusions approach each other drawn by the cavity bridge force (CBF), local active angles consolidate, and neck region sintering occurs. Based on the thermodynamic calculations of TiN, MnS, and MgO precipitation, the formation behaviors of complex inclusions of TiN-MnS, TiN-MgO-MA, and TiN-MA-MnS were investigated.

Protection of lithographic components from particle contamination

DOEpatents

Klebanoff, Leonard E.; Rader, Daniel J.

2000-01-01

A system that employs thermophoresis to protect lithographic surfaces from particle deposition and operates in an environment where the pressure is substantially constant and can be sub-atmospheric. The system (thermophoretic pellicle) comprises an enclosure that surrounds a lithographic component whose surface is being protected from particle deposition. The enclosure is provided with means for introducing a flow of gas into the chamber and at least one aperture that provides for access to the lithographic surface for the entry and exit of a beam of radiation, for example, and further controls gas flow into a surrounding low pressure environment such that a higher pressure is maintained within the enclosure and over the surface being protected. The lithographic component can be heated or, alternatively the walls of the enclosure can be cooled to establish a temperature gradient between the surface of the lithographic component and the walls of the enclosure, thereby enabling the thermophoretic force that resists particle deposition.

Method for protection of lithographic components from particle contamination

DOEpatents

Klebanoff, Leonard E.; Rader, Daniel J.

2001-07-03

A system that employs thermophoresis to protect lithographic surfaces from particle deposition and operates in an environment where the pressure is substantially constant and can be sub-atmospheric. The system (thermophoretic pellicle) comprises an enclosure that surrounds a lithographic component whose surface is being protected from particle deposition. The enclosure is provided with means for introducing a flow of gas into the chamber and at least one aperture that provides for access to the lithographic surface for the entry and exit of a beam of radiation, for example, and further controls gas flow into a surrounding low pressure environment such that a higher pressure is maintained within the enclosure and over the surface being protected. The lithographic component can be heated or, alternatively the walls of the enclosure can be cooled to establish a temperature gradient between the surface of the lithographic component and the walls of the enclosure, thereby enabling the thermophoretic force that resists particle deposition.

Detrital and Authigenic Magnetic Micro- and Nanoparticles in Pelagic Sediments of the Equatorial Atlantic

NASA Astrophysics Data System (ADS)

Franke, C.; von Dobeneck, T.; Dekkers, M.

2004-12-01

Magnetic paleofield and paleoenvironmental information of marine sediments is mostly carried by submicron magnetic particles from various sources. Most existing studies make plausible, but largely unconfirmed assumptions about the origin, mineralogy and grain size of the magnetic mineral assemblages of pelagic sediments. This study intends to provide a detailed characterization of magnetic micro- and nanoparticles in oxic to mildly suboxic sedimentary environments of the Equatorial Atlantic and compares three sites (Ceará Rise, Mid Atlantic Ridge (MAR), Sierra Leone Rise) along a W-E transect. This region offers magnetic particle sources such as continental dust, fluvial discharge and weathering of ocean ridge basalts. Remanence, hysteresis, low- and high-temperature rock magnetic investigations were performed on bulk sediments, magnetic extracts and heavy liquid separates and were combined with analytic scanning (SEM) and transmission (TEM) electron microscopy. Curie temperatures between 580 and 600° C indicate oxidized magnetite as the major low coercivity component in all samples. The Verwey transition ( ˜110 K) is weakly expressed in the samples from the Ceará Rise and the MAR and disappears at the Sierra Leone Rise. SEM studies on the magnetic extracts show that the quantitative main components are detrital titanomagnetite particles with increasing Ti-content throughout the transect towards the East. Magnetite particles with very low to zero Ti-content provide about one third of the detrital component. They often show shrinking cracks indicating external maghemitization. Further components are octahedral titanomagnetite crystals, silicates with (titano-) magnetite inclusions and spherules with low Ti-content. An important high coercive component, most likely goethite, is unsaturated at 2.5 T and missing in the magnetic extracts. It is manifested by a large discrepancy of the slopes in field cooling and the zero field cooling low-temperature curves, which disappear after heating to 340° C. Shape, grain size, roundness as well as the degree of preservation of the magnetic grains give insight into the transport mechanisms and regional provenances of the various components. The close coupling of ARM and IRM signals hints at a single source mechanism, eolian dust input, for micro- and nanoparticle fractions in the East of the transect. Therefore, the ARM/IRM ratio indicates mainly grain size variations related to varying wind intensity. In the western Equatorial Atlantic, the accumulation rates of the micro- and nanoparticles are much more weakly coupled. The coarser fraction is reflecting sea level controlled Amazon discharge while the fine fraction is yet to be identified by TEM. In contrary to the eastern part, the ARM/IRM signal of this region expresses rather a grain size mixing than sorting regime.

Observing single protein binding by optical transmission through a double nanohole aperture in a metal film

PubMed Central

Al Balushi, Ahmed A.; Zehtabi-Oskuie, Ana; Gordon, Reuven

2013-01-01

We experimentally demonstrate protein binding at the single particle level. A double nanohole (DNH) optical trap was used to hold onto a 20 nm biotin-coated polystyrene (PS) particle which subsequently is bound to streptavidin. Biotin-streptavidin binding has been detected by an increase in the optical transmission through the DNH. Similar optical transmission behavior was not observed when streptavidin binding sites where blocked by mixing streptavidin with excess biotin. Furthermore, interaction of non-functionalized PS particles with streptavidin did not induce a change in the optical transmission through the DNH. These results are promising as the DNH trap can make an excellent single molecule resolution sensor which would enable studying biomolecular interactions and dynamics at a single particle/molecule level. PMID:24049672

Diffraction data of core-shell nanoparticles from an X-ray free electron laser

DOE PAGES

Li, Xuanxuan; Chiu, Chun -Ya; Wang, Hsiang -Ju; ...

2017-04-11

X-ray free-electron lasers provide novel opportunities to conduct single particle analysis on nanoscale particles. Coherent diffractive imaging experiments were performed at the Linac Coherent Light Source (LCLS), SLAC National Laboratory, exposing single inorganic core-shell nanoparticles to femtosecond hard-X-ray pulses. Each facetted nanoparticle consisted of a crystalline gold core and a differently shaped palladium shell. Scattered intensities were observed up to about 7 nm resolution. Analysis of the scattering patterns revealed the size distribution of the samples, which is consistent with that obtained from direct real-space imaging by electron microscopy. Furthermore, scattering patterns resulting from single particles were selected and compiledmore » into a dataset which can be valuable for algorithm developments in single particle scattering research.« less

Particle size analysis of amalgam powder and handpiece generated specimens.

PubMed

Drummond, J L; Hathorn, R M; Cailas, M D; Karuhn, R

2001-07-01

The increasing interest in the elimination of amalgam particles from the dental waste (DW) stream, requires efficient devices to remove these particles. The major objective of this project was to perform a comparative evaluation of five basic methods of particle size analysis in terms of the instrument's ability to quantify the size distribution of the various components within the DW stream. The analytical techniques chosen were image analysis via scanning electron microscopy, standard wire mesh sieves, X-ray sedigraphy, laser diffraction, and electrozone analysis. The DW particle stream components were represented by amalgam powders and handpiece/diamond bur generated specimens of enamel; dentin, whole tooth, and condensed amalgam. Each analytical method quantified the examined DW particle stream components. However, X-ray sedigraphy, electrozone, and laser diffraction particle analyses provided similar results for determining particle distributions of DW samples. These three methods were able to more clearly quantify the properties of the examined powder and condensed amalgam samples. Furthermore, these methods indicated that a significant fraction of the DW stream contains particles less than 20 microm. The findings of this study indicated that the electrozone method is likely to be the most effective technique for quantifying the particle size distribution in the DW particle stream. This method required a relative small volume of sample, was not affected by density, shape factors or optical properties, and measured a sufficient number of particles to provide a reliable representation of the particle size distribution curve.

Doping evolution of spin and charge excitations in the Hubbard model

DOE PAGES

Kung, Y. F.; Nowadnick, E. A.; Jia, C. J.; ...

2015-11-05

We shed light on how electronic correlations vary across the phase diagram of the cuprate superconductors, examining the doping evolution of spin and charge excitations in the single-band Hubbard model using determinant quantum Monte Carlo (DQMC). In the single-particle response, we observe that the effects of correlations weaken rapidly with doping, such that one may expect the random phase approximation (RPA) to provide an adequate description of the two-particle response. In contrast, when compared to RPA, we find that significant residual correlations in the two-particle excitations persist up to 40% hole and 15% electron doping (the range of dopings achievedmore » in the cuprates). Ultimately, these fundamental differences between the doping evolution of single- and multi-particle renormalizations show that conclusions drawn from single-particle processes cannot necessarily be applied to multi-particle excitations. Eventually, the system smoothly transitions via a momentum-dependent crossover into a weakly correlated metallic state where the spin and charge excitation spectra exhibit similar behavior and where RPA provides an adequate description.« less

Single-particle characterization of urban aerosol particles collected in three Korean cites using low-Z electron probe X-ray microanalysis.

PubMed

Ro, Chul-Un; Kim, HyeKyeong; Oh, Keun-Young; Yea, Sun Kyung; Lee, Chong Bum; Jang, Meongdo; Van Grieken, René

2002-11-15

A recently developed single-particle analytical technique, called low-Z electron probe X-ray microanalysis (low-Z EPMA), was applied to characterize urban aerosol particles collected in three cities of Korea (Seoul, CheongJu, and ChunCheon) on single days in the winter of 1999. In this study, it is clearly demonstrated that the low-Z EPMA technique can provide detailed and quantitative information on the chemical composition of particles in the urban atmosphere. The collected aerosol particles were analyzed and classified on the basis of their chemical species. Various types of particles were identified, such as soil-derived, carbonaceous, marine-originated, and anthropogenic particles. In the sample collected in Seoul, carbonaceous, aluminosilicates, silicon dioxide, and calcium carbonate aerosol particles were abundantly encountered. In the CheongJu and ChunCheon samples, carbonaceous, aluminosilicates, reacted sea salts, and ammonium sulfate aerosol particles were often seen. However, in the CheongJu sample, ammonium sulfate particles were the most abundant in the fine fraction. Also, calcium sulfate and nitrate particles were significantly observed. In the ChunCheon sample, organic particles were the most abundant in the fine fraction. Also, sodium nitrate particles were seen at high levels. The ChunCheon sample seemed to be strongly influenced by sea-salt aerosols originating from the Yellow Sea, which is located about 115 km away from the city.

Investigation of the thickness non-uniformity of the very thin silicon-strip detectors

NASA Astrophysics Data System (ADS)

Liu, Qiang; Ye, Yanlin; Li, Zhihuan; Lin, Chengjian; Jia, Huiming; Ge, Yucheng; Li, Qite; Lou, Jianling; Yang, Xiaofei; Yang, Biao; Feng, Jun; Zang, Hongliang; Chen, Zhiqiang; Liu, Yang; Liu, Wei; Chen, Sidong; Yu, Hanzhou; Li, Jingjing; Zhang, Yun; Yang, Feng; Yang, Lei; Ma, Nanru; Sun, Lijie; Wang, Dongxi

2018-07-01

The properties of some very thin (∼ 20 μm) large-area Single-sided Silicon-Strip Detectors (SSSDs) were investigated by using the 12C-particles elastically scattered from a Au target. In the detection system, each thin SSSD was installed in front of a thick (300 μm or 500 μm) Double-sided Silicon-Strip Detector (DSSD) to form a ΔE - E particle-telescope. The energy calibration of these detectors was realized by varying the beam energy and also by the irradiation from a three-component α-particle source. The thickness distribution each SSSD is precisely determined from the energy loss in the thin layer, which was independently measured by the corresponding DSSD. It is found that, for the SSSD with the nominal thicknesses of ∼ 20 μm, the real thickness may vary by several μm over the active area. The reason for this large non-uniformity still needs to be investigated. For the present application, this non-uniformity could be corrected according to the known pixel-thickness. This correction allows to restore a good particle identification (PID) performance for the entire large-area detector, the importance of which is demonstrated by an example of measuring the cluster-decays of the highly-excited resonant states in 16O.

Probabilistic homogenization of random composite with ellipsoidal particle reinforcement by the iterative stochastic finite element method

NASA Astrophysics Data System (ADS)

Sokołowski, Damian; Kamiński, Marcin

2018-01-01

This study proposes a framework for determination of basic probabilistic characteristics of the orthotropic homogenized elastic properties of the periodic composite reinforced with ellipsoidal particles and a high stiffness contrast between the reinforcement and the matrix. Homogenization problem, solved by the Iterative Stochastic Finite Element Method (ISFEM) is implemented according to the stochastic perturbation, Monte Carlo simulation and semi-analytical techniques with the use of cubic Representative Volume Element (RVE) of this composite containing single particle. The given input Gaussian random variable is Young modulus of the matrix, while 3D homogenization scheme is based on numerical determination of the strain energy of the RVE under uniform unit stretches carried out in the FEM system ABAQUS. The entire series of several deterministic solutions with varying Young modulus of the matrix serves for the Weighted Least Squares Method (WLSM) recovery of polynomial response functions finally used in stochastic Taylor expansions inherent for the ISFEM. A numerical example consists of the High Density Polyurethane (HDPU) reinforced with the Carbon Black particle. It is numerically investigated (1) if the resulting homogenized characteristics are also Gaussian and (2) how the uncertainty in matrix Young modulus affects the effective stiffness tensor components and their PDF (Probability Density Function).

TrackArt: the user friendly interface for single molecule tracking data analysis and simulation applied to complex diffusion in mica supported lipid bilayers.

PubMed

Matysik, Artur; Kraut, Rachel S

2014-05-01

Single molecule tracking (SMT) analysis of fluorescently tagged lipid and protein probes is an attractive alternative to ensemble averaged methods such as fluorescence correlation spectroscopy (FCS) or fluorescence recovery after photobleaching (FRAP) for measuring diffusion in artificial and plasma membranes. The meaningful estimation of diffusion coefficients and their errors is however not straightforward, and is heavily dependent on sample type, acquisition method, and equipment used. Many approaches require advanced computing and programming skills for their implementation. Here we present TrackArt software, an accessible graphic interface for simulation and complex analysis of multiple particle paths. Imported trajectories can be filtered to eliminate spurious or corrupted tracks, and are then analyzed using several previously described methodologies, to yield single or multiple diffusion coefficients, their population fractions, and estimated errors. We use TrackArt to analyze the single-molecule diffusion behavior of a sphingolipid analog SM-Atto647N, in mica supported DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine) bilayers. Fitting with a two-component diffusion model confirms the existence of two separate populations of diffusing particles in these bilayers on mica. As a demonstration of the TrackArt workflow, we characterize and discuss the effective activation energies required to increase the diffusion rates of these populations, obtained from Arrhenius plots of temperature-dependent diffusion. Finally, TrackArt provides a simulation module, allowing the user to generate models with multiple particle trajectories, diffusing with different characteristics. Maps of domains, acting as impermeable or permeable obstacles for particles diffusing with given rate constants and diffusion coefficients, can be simulated or imported from an image. Importantly, this allows one to use simulated data with a known diffusion behavior as a comparison for results acquired using particular algorithms on actual, "natural" samples whose diffusion behavior is to be extracted. It can also serve as a tool for demonstrating diffusion principles. TrackArt is an open source, platform-independent, Matlab-based graphical user interface, and is easy to use even for those unfamiliar with the Matlab programming environment. TrackArt can be used for accurate simulation and analysis of complex diffusion data, such as diffusion in lipid bilayers, providing publication-quality formatted results.

Aging fingerprints in combustion particles

NASA Astrophysics Data System (ADS)

Zelenay, V.; Mooser, R.; Tritscher, T.; Křepelová, A.; Heringa, M. F.; Chirico, R.; Prévôt, A. S. H.; Weingartner, E.; Baltensperger, U.; Dommen, J.; Watts, B.; Raabe, J.; Huthwelker, T.; Ammann, M.

2011-05-01

Soot particles can significantly influence the Earth's climate by absorbing and scattering solar radiation as well as by acting as cloud condensation nuclei. However, despite their environmental (as well as economic and political) importance, the way these properties are affected by atmospheric processing is still a subject of discussion. In this work, soot particles emitted from two different cars, a EURO 2 transporter, a EURO 3 passenger vehicle, and a wood stove were investigated on a single-particle basis. The emitted exhaust, including the particulate and the gas phase, was processed in a smog chamber with artificial solar radiation. Single particle specimens of both unprocessed and aged soot were characterized using x-ray absorption spectroscopy and scanning electron microscopy. Comparison of the spectra from the unprocessed and aged soot particles revealed changes in the carbon functional group content, such as that of carboxylic carbon, which can be ascribed to both the condensation of secondary organic compounds on the soot particles and oxidation of primary soot particles upon photochemical aging. Changes in the morphology and size of the single soot particles were also observed upon aging. Furthermore, we show that the soot particles take up water in humid environments and that their water uptake capacity increases with photochemical aging.

Hybrid gas-to-particle conversion and chemical vapor deposition for production of high-surface area films

NASA Astrophysics Data System (ADS)

Nguyen, Quynh Tan

A hybrid process, based upon gas-to-particle conversion and chemical vapor deposition, is presented as an alternative technique for producing porous films with the main advantages of solvent-free, low-substrate temperature operation. Starting from solid precursors, nanoparticles were produced in the vapor phase. Downstream of this reaction zone, these nanoparticles were collected via thermophoresis onto a cooled substrate forming a porous film. Initially, alumina (Al2O3) films were produced. Later, multi-component processing was explored by incorporating platinum (Pt) nanoparticles into the Al2O3 matrix leading to the production of Pt/Al 2O3 films by two routes: simultaneous precursor injection processing or by a layer-by-layer approach. In single component processing, the formation of nanoparticle aggregates was evident within the amorphous Al2O3 films. Aggregates, composed of these particles, are likely held together by relatively weak van der Waals forces leading to the observed poor physical cohesion. In multi-component processing, reasonable control of composition and distribution of species is possible with Pt nanoparticles appearing to be co-agglomerated with alumina. Deposited crystalline Pt nanoparticles may encourage the crystallization of the amorphous Al2O3. Finally, from chemisorption results, the produced sample appears to have potentially greater catalytic activity than a commercially available standard. A model is in development to study nanoparticle interactions with a gas and deposition occurring in stagnation flow onto the cooled horizontal substrate within the tubular reactor. Using velocity and temperature fields generated from numerical solutions to the Navier-Stokes and energy equations, particle trajectories were calculated from the summation of drag, gravitational, thermophoretic, and Brownian forces. In rectangular coordinates, cooling stage width to reactor diameter ratio, deposition stage temperature, and initial velocity were the primary parameters varied in this study. An optimum balance between thermophoretic and drag forces appears to be the key factor in obtaining high yield and surface uniformity in the films. The results also suggest that Brownian motion is not a significant contributor to deposition under conditions in this study.

Endotoxin and β-1,3-d-Glucan in Concentrated Ambient Particles Induce Rapid Increase in Blood Pressure in Controlled Human Exposures.

PubMed

Zhong, Jia; Urch, Bruce; Speck, Mary; Coull, Brent A; Koutrakis, Petros; Thorne, Peter S; Scott, James; Liu, Ling; Brook, Robert D; Behbod, Behrooz; Gibson, Heike; Silverman, Frances; Mittleman, Murray A; Baccarelli, Andrea A; Gold, Diane R

2015-09-01

Short-term exposure to particulate matter (PM) is associated with increased blood pressure (BP) in epidemiological studies. Understanding the impact of specific PM components on BP is essential in developing effective risk-reduction strategies. We investigated the association between endotoxin and β-1,3-d-Glucan-two major biological PM components-and BP. We also examined whether vascular endothelial growth factor, a vasodilatory inflammatory marker, modified these associations. We conducted a single-blind, randomized, crossover trial of controlled human exposure to concentrated ambient particles with 50 healthy adults. Particle-associated-endotoxin and β-1,3-d-Glucan were sampled using polycarbonate-membrane-filters. Supine resting systolic BP and diastolic BP were measured pre-, 0.5-hour post-, and 20-hour postexposure. Urine vascular endothelial growth factor concentration was determined using enzyme-linked immunosorbant assay and creatinine-corrected. Exposures to endotoxin and β-1,3-d-Glucan for 130 minutes were associated with increases in BPs: at 0.5-hour postexposure, every doubling in endotoxin concentration was associated with 1.73 mm Hg higher systolic BP (95% confidence interval, 0.28, 3.18; P=0.02) and 2.07 mm Hg higher diastolic BP (95% confidence interval, 0.74, 3.39; P=0.003); every doubling in β-1,3-d-Glucan concentration was associated with 0.80 mm Hg higher systolic BP (95% confidence interval, -0.07, 1.67; P=0.07) and 0.88 mm Hg higher diastolic BP (95% confidence interval, 0.09, 1.66; P=0.03). Vascular endothelial growth factor rose after concentrated ambient particle endotoxin exposure and attenuated the association between endotoxin and 0.5-hour postexposure diastolic BP (Pinteraction=0.02). In healthy adults, short-term endotoxin and β-1,3-d-Glucan exposures were associated with increased BP. Our findings suggest that the biological PM components contribute to PM-related cardiovascular outcomes, and postexposure vascular endothelial growth factor elevation might be an adaptive response that attenuates these effects. © 2015 American Heart Association, Inc.

The temporal evolution process from fluorescence bleaching to clean Raman spectra of single solid particles optically trapped in air

NASA Astrophysics Data System (ADS)

Gong, Zhiyong; Pan, Yong-Le; Videen, Gorden; Wang, Chuji

2017-12-01

We observe the entire temporal evolution process of fluorescence and Raman spectra of single solid particles optically trapped in air. The spectra initially contain strong fluorescence with weak Raman peaks, then the fluorescence was bleached within seconds, and finally only the clean Raman peaks remain. We construct an optical trap using two counter-propagating hollow beams, which is able to stably trap both absorbing and non-absorbing particles in air, for observing such temporal processes. This technique offers a new method to study dynamic changes in the fluorescence and Raman spectra from a single optically trapped particle in air.

Single Charged Particle Identification in Nuclear Emulsion Using Multiple Coulomb Scattering Method

NASA Astrophysics Data System (ADS)

Tint, Khin T.; Endo, Yoko; Hoshino, Kaoru; Ito, Hiroki; Itonaga, Kazunori; Kinbara, Shinji; Kobayashi, Hidetaka; Mishina, Akihiro; Soe, Myint K.; Yoshida, Junya; Nakazawa, Kazuma

Development of particle identification technique for single charged particles such as Ξ- hyperon, proton, K- and π- mesons is on-going by measuring multiple Coulomb scattering in nuclear emulsion. We generated several thousands of tracks of the single charged particles in nuclear emulsion stacks with GEANT 4 simulation and obtained second difference in constant Sagitta Method. We found that recognition of Ξ- hyperon from π- mesons is well satisfied, although that from K- and proton are a little difficult. On the other hand, the consistency of second difference of real Ξ- hyperon and pi meson tracks and simulation results were also confirmed.

Phase Fluctuations and a Negative U Hubbard Model: Single-Particle and Thermodyanic Properties in a Conserving Approximation

NASA Astrophysics Data System (ADS)

Serene, J. W.; Deisz, J. J.; Hess, D. W.

1997-03-01

Calculations performed in the fluctuation exchange approximation for the single-band 2D Hubbard model on a cylinder and threaded by a flux, show the appearance of a finite superfluid density below T ~ 0.13t, for U=-4t and at three-eighths filling.(J.J. Deisz, D.W. Hess, Bull. Am. Phys. Soc. 41, 239 (1996); J.J. Deisz, D.W. Hess, and J.W. Serene, in preparation.) We show the evolution, with decreasing temperature, of the single-particle spectral function, the self-energy, the particle-particle T-matrix, and thermodynamic properties as the superfluid state is approached and entered.

Interplay of single particle and collective response in molecular dynamics simulation of dusty plasma system

NASA Astrophysics Data System (ADS)

Maity, Srimanta; Das, Amita; Kumar, Sandeep; Tiwari, Sanat Kumar

2018-04-01

The collective response of the plasma medium is well known and has been explored extensively in the context of dusty plasma medium. On the other hand, the individual particle response associated with the collisional character giving rise to the dissipative phenomena has not been explored adequately. In this paper, two-dimensional molecular dynamics simulation of dust particles interacting via Yukawa potential has been considered. It has been shown that disturbances induced in a dust crystal elicit both collective and single particle responses. Generation of a few particles moving at speeds considerably higher than acoustic and/or shock speed (excited by the external disturbance) is observed. This is an indication of a single particle response. Furthermore, as these individual energetic particles propagate, the dust crystal is observed to crack along their path. Initially when the energy is high, these particles generate secondary energetic particles by the collisional scattering process. However, ultimately as these particles slow down they excite a collective response in the dust medium at secondary locations in a region which is undisturbed by the primary external disturbance. The condition when the cracking of the crystal stops and collective excitations get initiated has been identified quantitatively. The trailing collective primary disturbances would thus often encounter a disturbed medium with secondary and tertiary collective perturbations, thereby suffering significant modification in its propagation. It is thus clear that there is an interesting interplay (other than mere dissipation) between the single particle and collective response which governs the dynamics of any disturbance introduced in the medium.

Raman Spectroscopy and Microphysics of Single PSC Precursor Particles Suspended in a Quadrupole Trap

NASA Astrophysics Data System (ADS)

Sonnenfroh, D. M.; Hunter, A. J.; Rawlins, W. T.

2001-12-01

Polar stratospheric clouds (PSCs) consist primarily of solid nitric acid trihydrate (NAT) particles, which are thought to nucleate via HNO3 uptake on background sulfuric acid particles at temperatures below 195 K. The mechanism for this process is uncertain, and depends on whether the sulfuric acid particles are solid or liquid at these temperatures. Previous results from laboratory and field measurements are mixed; our previous single-particle laboratory experiments showed that binary H2SO4/H2O particles at stratospheric compositions are essentially metastable in the liquid phase when cooled to PSC temperatures. Currently, we are investigating the detailed microphysics of binary (H2SO4/H2O) and ternary (HNO3/H2SO4/H2O) single particles suspended in an electrodynamic levitator, using optical elastic scattering and Raman spectroscopy to observe changes in phase and composition. Single-particle Raman spectra for supercooled binary particles exhibit spectral distributions which alter markedly with decreasing temperature down to 190 K. The variations signify increasing dissociation of HSO4(-) to SO4(-2) with decreasing temperature, consistent with measurements for bulk solutions. Upon gradual warming of supercooled liquid binary particles, some of them freeze briefly in a narrow "window" of the phase diagram, near 210 K and 60 weight per cent H2SO4. We will discuss the Raman spectroscopy and microphysical behavior of the liquid and frozen particles for both the binary and ternary systems. This research was supported by the NASA Atmospheric Effects of Aviation Program.

Enery Efficient Press and Sinter of Titanium Powder for Low-Cost Components in Vehicle Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas Zwitter; Phillip Nash; Xiaoyan Xu

2011-03-31

This is the final technical report for the Department of Energy NETL project NT01931 Energy Efficient Press and Sinter of Titanium Powder for Low-Cost Components in Vehicle Applications. Titanium has been identified as one of the key materials with the required strength that can reduce the weight of automotive components and thereby reduce fuel consumption. Working with newly developed sources of titanium powder, Webster-Hoff will develop the processing technology to manufacture low cost vehicle components using the single press/single sinter techniques developed for iron based powder metallurgy today. Working with an automotive or truck manufacturer, Webster-Hoff will demonstrate the feasibilitymore » of manufacturing a press and sinter titanium component for a vehicle application. The project objective is two-fold, to develop the technology for manufacturing press and sinter titanium components, and to demonstrate the feasibility of producing a titanium component for a vehicle application. The lowest cost method for converting metal powder into a net shape part is the Powder Metallurgy Press and Sinter Process. The method involves compaction of the metal powder in a tool (usually a die and punches, upper and lower) at a high pressure (up to 60 TSI or 827 MPa) to form a green compact with the net shape of the final component. The powder in the green compact is held together by the compression bonds between the powder particles. The sinter process then converts the green compact to a metallurgically bonded net shape part through the process of solid state diffusion. The goal of this project is to expand the understanding and application of press and sinter technology to Titanium Powder applications, developing techniques to manufacture net shape Titanium components via the press and sinter process. In addition, working with a vehicle manufacturer, demonstrate the feasibility of producing a titanium component for a vehicle. This is not a research program, but rather a project to develop a process for press and sinter of net shape Titanium components. All of these project objectives have been successfully completed.« less

Hygroscopic properties of internally mixed particles composed of NaCl and water-soluble organic acids.

PubMed

Ghorai, Suman; Wang, Bingbing; Tivanski, Alexei; Laskin, Alexander

2014-02-18

Atmospheric aging of naturally emitted marine aerosol often leads to formation of internally mixed particles composed of sea salts and water-soluble organic compounds of anthropogenic origin. Mixing of sea salt and organic components has profound effects on the evolving chemical composition and hygroscopic properties of the resulted particles, which are poorly understood. Here, we have studied chemical composition and hygroscopic properties of laboratory generated NaCl particles mixed with malonic acid (MA) and glutaric acid (GA) at different molar ratios using micro-FTIR spectroscopy, atomic force microscopy, and X-ray elemental microanalysis. Hygroscopic properties of internally mixed NaCl and organic acid particles were distinctly different from pure components and varied significantly with the type and amount of organic compound present. Experimental results were in a good agreement with the AIM modeling calculations of gas/liquid/solid partitioning in studied systems. X-ray elemental microanalysis of particles showed that Cl/Na ratio decreased with increasing organic acid component in the particles with MA yielding lower ratios relative to GA. We attribute the depletion of chloride to the formation of sodium malonate and sodium glutarate salts resulted by HCl evaporation from dehydrating particles.

Hygroscopic Properties of Internally Mixed Particles Composed of NaCl and Water-Soluble Organic Acids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghorai, Suman; Wang, Bingbing; Tivanski, Alexei V.

Atmospheric aging of naturally emitted marine aerosol often leads to formation of internally mixed particles composed of sea salts and water soluble organic compounds of anthropogenic origin. Mixing of sea salt and organic components has profound effects on the evolving chemical composition and hygroscopic properties of the resulted particles, which are poorly understood. Here, we have studied chemical composition and hygroscopic properties of laboratory generated NaCl particles mixed with malonic acid (MA) and glutaric acid (GA) at different molar ratios using micro-FTIR spectroscopy and X-ray elemental microanalysis.Hygroscopic properties of inte rnally mixed NaCl and organic acid particles were distinctly differentmore » from pure components and varied significantly with the type and amount of organic compound present. Experimental results were in a good agreement with the AIM modeling calculations of gas/liquid/solid partitioning in studied systems. X-ray elemental microanalysis of particles showed that Cl/Na ratio decreased with increasing organic acid component in the particles with MA yielding lower ratios relative to GA. We attribute the depletion of chloride to the formation of Na-malonate and Na-glutarate salts resulted by HCl evaporation from dehydrating particles.« less

A Binary Segmentation Approach for Boxing Ribosome Particles in Cryo EM Micrographs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adiga, Umesh P.S.; Malladi, Ravi; Baxter, William

Three-dimensional reconstruction of ribosome particles from electron micrographs requires selection of many single-particle images. Roughly 100,000 particles are required to achieve approximately 10 angstrom resolution. Manual selection of particles, by visual observation of the micrographs on a computer screen, is recognized as a bottleneck in automated single particle reconstruction. This paper describes an efficient approach for automated boxing of ribosome particles in micrographs. Use of a fast, anisotropic non-linear reaction-diffusion method to pre-process micrographs and rank-leveling to enhance the contrast between particles and the background, followed by binary and morphological segmentation constitute the core of this technique. Modifying the shapemore » of the particles to facilitate segmentation of individual particles within clusters and boxing the isolated particles is successfully attempted. Tests on a limited number of micrographs have shown that over 80 percent success is achieved in automatic particle picking.« less

Characterisation of a complex thin walled structure fabricated by selective laser melting using a ferritic oxide dispersion strengthened steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boegelein, Thomas, E-mail: t.boegelein@liv.ac.uk; Louvis, Eleftherios; Dawson, Karl

2016-02-15

Oxide dispersion strengthened (ODS) alloys exhibit superior mechanical and physical properties due to the presence of nanoscopic Y(Al, Ti) oxide precipitates, but their manufacturing process is complex. The present study is aimed at further investigation of the application of an alternative, Additive Manufacturing (AM) technique, Selective Laser Melting (SLM), to the production of consolidated ODS alloy components. Mechanically alloyed PM2000 (ODS-FeCrAl) powders have been consolidated and a fine dispersion of Y-containing precipitates were observed in an as built thin-walled component, but these particles were typically poly-crystalline and contained a variety of elements including O, Al, Ti, Cr and Fe. Applicationmore » of post-build heat treatments resulted in the modification of particle structures and compositions; in the annealed condition most precipitates were transformed to single crystal yttrium aluminium oxides. During the annealing treatment, precipitate distributions homogenised and localised variations in number density were diminished. The resulting volume fractions of those precipitates were 25–40% lower than have been reported in conventionally processed PM2000, which was attributed to Y-rich slag-like surface features and inclusions formed during SLM. - Highlights: • A wall structure was grown from ODS steel powder using selective laser melting. • A fine dispersion of nano-precipitates was apparent in as-build material. • Precipitates were multi-phased containing several elements, e.g. O, Ti, Al, Fe, Cr, Y. • Post-build annealing changed those into typically single-crystalline Y–Al–O. • The anneal also reduced and stabilised the volume fraction of precipitates to ~ 0.006.« less

Infrasound signal detection and characterization using ground-coupled airwaves on a single seismo-acoustic sensor pair

NASA Astrophysics Data System (ADS)

McKee, K. F.; Fee, D.; Haney, M. M.; Lyons, J. J.; Matoza, R. S.

2016-12-01

A ground-coupled airwave (GCA) occurs when an incident atmospheric pressure wave encounters the Earth's surface and part of the energy of the wave is transferred to the ground (i.e. coupled to the ground) as a seismic wave. This seismic wave propagates as a surface Rayleigh wave evidenced by the retrograde particle motion detected on a three-component seismometer. Acoustic waves recorded on a collocated microphone and seismometer can be coherent and have a 90-degree phase difference, predicted by theory and in agreement with observations. If the sensors are separated relative to the frequencies of interest, usually 10s to 100s of meters, then recorded wind noise becomes incoherent and an additional phase shift is present due to the separation distance. These characteristics of GCAs have been used to distinguish wind noise from other sources as well as to determine the acoustic contribution to seismic recordings. Here we aim to develop a minimalist infrasound signal detection and characterization technique requiring just one microphone and one three-component seismometer. Based on GCA theory, determining a source azimuth should be possible using a single seismo-acoustic sensor pair by utilizing the phase difference and exploiting the characteristic particle motion. We will use synthetic seismo-acoustic data generated by a coupled Earth-atmosphere 3D finite difference code to test and tune the detection and characterization method. The method will then be further tested using various well-constrained sources (e.g. Chelyabinsk meteor, Pagan Volcano, Cleveland Volcano). Such a technique would be advantageous in situations where resources are limited and large sensor networks are not feasible.

Single fiber model of particle retention in an acoustically driven porous mesh.

PubMed

Grossner, Michael T; Penrod, Alan E; Belovich, Joanne M; Feke, Donald L

2003-03-01

A method for the capture of small particles (tens of microns in diameter) from a continuously flowing suspension has recently been reported. This technique relies on a standing acoustic wave resonating in a rectangular chamber filled with a high-porosity mesh. Particles are retained in this chamber via a complex interaction between the acoustic field and the porous mesh. Although the mesh has a pore size two orders of magnitude larger than the particle diameter, collection efficiencies of 90% have been measured. A mathematical model has been developed to understand the experimentally observed phenomena and to be able to predict filtration performance. By examining a small region (a single fiber) of the porous mesh, the model has duplicated several experimental events such as the focusing of particles near an element of the mesh and the levitation of particles within pores. The single-fiber analysis forms the basis of modeling the overall performance of the particle filtration system. Copyright 2002 Elsevier Science B.V.

Quantitative real-time single particle analysis of virions.

PubMed

Heider, Susanne; Metzner, Christoph

2014-08-01

Providing information about single virus particles has for a long time been mainly the domain of electron microscopy. More recently, technologies have been developed-or adapted from other fields, such as nanotechnology-to allow for the real-time quantification of physical virion particles, while supplying additional information such as particle diameter concomitantly. These technologies have progressed to the stage of commercialization increasing the speed of viral titer measurements from hours to minutes, thus providing a significant advantage for many aspects of virology research and biotechnology applications. Additional advantages lie in the broad spectrum of virus species that may be measured and the possibility to determine the ratio of infectious to total particles. A series of disadvantages remain associated with these technologies, such as a low specificity for viral particles. In this review we will discuss these technologies by comparing four systems for real-time single virus particle analysis and quantification. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Charged particle beam scanning using deformed high gradient insulator

DOEpatents

Chen, Yu -Jiuan

2015-10-06

Devices and methods are provided to allow rapid deflection of a charged particle beam. The disclosed devices can, for example, be used as part of a hadron therapy system to allow scanning of a target area within a patient's body. The disclosed charged particle beam deflectors include a dielectric wall accelerator (DWA) with a hollow center and a dielectric wall that is substantially parallel to a z-axis that runs through the hollow center. The dielectric wall includes one or more deformed high gradient insulators (HGIs) that are configured to produce an electric field with an component in a direction perpendicular to the z-axis. A control component is also provided to establish the electric field component in the direction perpendicular to the z-axis and to control deflection of a charged particle beam in the direction perpendicular to the z-axis as the charged particle beam travels through the hollow center of the DWA.

Ground-State Wave Function with Interactions between Different Species in M-Component Miscible Bose-Einstein Condensates

NASA Astrophysics Data System (ADS)

Kohno, Wataru; Kirikoshi, Akimitsu; Kita, Takafumi

2018-03-01

We construct a variational ground-state wave function of weakly interacting M-component Bose-Einstein condensates beyond the mean-field theory by incorporating the dynamical 3/2-body processes, where one of the two colliding particles drops into the condensate and vice versa. Our numerical results with various masses and particle numbers show that the 3/2-body processes between different particles make finite contributions to lowering the ground-state energy, implying that many-body correlation effects between different particles are essential even in the weak-coupling regime of the Bose-Einstein condensates. We also consider the stability condition for 2-component miscible states using the new ground-state wave function. Through this calculation, we obtain the relation UAB2/UAAUBB < 1 + α , where Uij is the effective contact potential between particles i and j and α is the correction, which originates from the 3/2- and 2-body processes.