Reversible Li storage for nanosize cation/anion-disordered rocksalt-type oxyfluorides: LiMoO2 - x LiF (0 ≤ x ≤ 2) binary system

NASA Astrophysics Data System (ADS)

Takeda, Nanami; Hoshino, Satoshi; Xie, Lixin; Chen, Shuo; Ikeuchi, Issei; Natsui, Ryuichi; Nakura, Kensuke; Yabuuchi, Naoaki

2017-11-01

A binary system of LiMoO2 - x LiF (0 ≤ x ≤ 2), Li1+xMoO2Fx, is systematically studied as potential positive electrode materials for rechargeable Li batteries. Single phase and nanosized samples on this binary system are successfully prepared by using a mechanical milling route. Crystal structures and Li storage properties on the binary system are also examined. Li2MoO2F (x = 1), which is classified as a cation-/anion-disordered rocksalt-type structure and is a thermodynamically metastable phase, delivers a large reversible capacity of over 300 mAh g-1 in Li cells with good reversibility. Highly reversible Li storage is realized for Li2MoO2F consisting of nanosized particles based on Mo3+/Mo5+ two-electron redox as evidenced by ex-situ X-ray absorption spectroscopy coupled with ex-situ X-ray diffractometry. Moreover, the presence of the most electronegative element in the framework structure effectively increases the electrode potential of Mo redox through an inductive effect. From these results, potential of nanosized lithium molybdenum oxyfluorides for high-capacity positive electrode materials of rechargeable Li batteries are discussed.

Highly efficient green up-conversion luminescence of Nd3+-Yb3+-Ho3+ codoped fluorite-type nanocrystals in transparent glass ceramics

NASA Astrophysics Data System (ADS)

Qiu, Jianbei; Kawamoto, Yoji; Zhang, Junjie

2002-11-01

Oxyfluoride glasses were developed with composition 30SiO2[middle dot]15AlO1.5[middle dot]28PbF2[middle dot]22CdF2[middle dot](4.8-x)GdF3[middle dot]0.1NdF3[middle dot]0.1HoF3[middle dot]xYbF3 (x=0, 0.1, 0.2, 0.5, 1, 2, 3, 4, and 4.8) in mole percent. Powder x-ray diffraction analysis revealed that the heat treatments of the oxyfluoride glasses at 450 degC for 0.5 h cause the precipitation of Nd3+-Yb3+-Ho3+ codoped fluorite-type nanocrystals of about 16.3 nm in diameter in the glass matrix. These transparent glass ceramics exhibited very strong green up-conversion luminescence due to the Ho3+: (5F4, 5S2)[right arrow]5I8 transition under 800 nm excitation. The intensity of the green up-conversion luminescence in a 1 mol % YbF3-containing glass ceramic was found to be about 120 times stronger than that in the precursor oxyfluoride glass. The reason for the highly efficient Ho3+ up-conversion luminescence in the oxyfluoride glass ceramics is discussed. An up-conversion mechanism is also proposed.

Intense 2.7 μm mid-infrared emission of Er{sup 3+} in oxyfluoride glass ceramic containing NaYF{sub 4} nanocrystals

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

Liu, Yin; Liu, Xueyun; Wang, Weichao

2016-04-15

Highlights: • Transparent oxyfluoride glass-ceramics containing NaYF{sub 4}:Er{sup 3+} nanocrystals have been prepared. • Intense 2.7 μm emission of the glass-ceramics has been demonstrated. • Prolonged decay lifetimes of Er{sup 3+}:{sup 4}I{sub 11/2} and {sup 4}I{sub 13/2} levels have been achieved. - Abstract: Transparent oxyfluoride glass ceramics containing NaYF{sub 4}:Er{sup 3+} nanocrystals have been prepared by melt quenching and subsequent thermal treatment. X-ray diffraction and high-resolution transmission electron microscopy analysis confirmed the precipitation of NaYF{sub 4} nanocrystals in glass. Energy dispersive spectrometer results evidenced the preferential concentration of Er{sup 3+} ions in nanocrystals. Mid-infrared, upconversion, and near-infrared emissions were measuredmore » upon excitation with 980 nm laser diode and the luminescence mechanisms were discussed. Intense 2.7 μm emission originating from the Er{sup 3+}:{sup 4}I{sub 11/2} → {sup 4}I{sub 13/2} transition was achieved due to the incorporation of Er{sup 3+} ions into the precipitated low phonon energy fluoride nanocrystals. The results indicate that oxyfluoride glass ceramic containing NaYF{sub 4}:Er{sup 3+} nanocrystals is a promising candidate material for 2.7 μm laser.« less

Novel duplex vapor-electrochemical method for silicon solar cells

NASA Technical Reports Server (NTRS)

Kapur, V. K.; Nanis, L.; Sanjurjo, A.

1977-01-01

Silicon was produced by alternate pulse feeding of the reactants SiF4 gas and liquid sodium. The average temperature in the reactor could be controlled, by regulating the amount of reactant in each pulse. Silicon tetrafluoride gas was analyzed by mass spectrometry to determine the nature and amount of contained volatile impurities which included silicon oxyfluorides, sulfur oxyfluorides, and sulfur dioxide. Sodium metal was analyzed by emission spectrography, and it was found to contain only calcium and copper as impurities.

Optical properties of rare earth doped transparent oxyfluoride glass ceramics

NASA Astrophysics Data System (ADS)

Mendez-Ramos, J.; Lavin, V.; Martin, I. R.; Rodriguez-Mendoza, U. R.; Rodriguez, V. D.; Lozano-Gorrin, A. D.; Nunez, P.

2003-01-01

Optical properties of Eu3+ ions in oxyfluoride glasses and glass ceramics doped with low concentration (0.1 mol%) have been analysed and compared with previous results for high concentrated samples (2.5 mol%). The Eu3+ ions in the low dopant concentration glass ceramics are diluted into like crystalline environments with higher symmetry and lower coupled phonons energy than in the precursor glasses. Fluorescence line narrowing measurements indicate the presence of two main fluoride site distributions for the Eu3+ ions in these low concentrated glass ceramics.

Improvement of Er 3+ emissions in oxyfluoride glass ceramic nano-composite by thermal treatment

NASA Astrophysics Data System (ADS)

Chen, Daqin; Wang, Yuansheng; Yu, Yunlong; Ma, En

2006-05-01

In order to improve the 1.53 μm emission of Er 3+-doped oxyfluoride glass ceramic containing CaF 2 nano-crystals, series of samples with same Er 3+ doping lever thermal treated under different conditions were prepared. The UV-VIR-NIR absorption spectra, near-infrared and up-conversion emission spectra, and 4I13/2 decay curves were measured. Based on Judd-Ofelt theory, the radiative transition probability, fluorescence branching ratio and radiative decay time of various metastable transitions of precursor glass and glass ceramics were evaluated. With the increasing of heating temperature, the Judd-Ofelt intensity parameter Ω2 monotonously decreased from 4.39×10 -20 to 2.72×10 -20 cm 2; the emission lifetime and quantum efficiency significantly increased from 5.9 to 8.0 ms and 70% to 98%, respectively. The wavelength dependence of gain cross-sections of oxyfluoride glass and glass ceramics were computed to be relatively flat in the range of 1530-1565 nm for population inversion from 0.7 to 1.0.

White light emission of dysprosium doped lanthanum calcium phosphate oxide and oxyfluoride glasses

NASA Astrophysics Data System (ADS)

Luewarasirikul, N.; Kim, H. J.; Meejitpaisan, P.; Kaewkhao, J.

2017-04-01

Lanthanum calcium phosphate oxide and oxyfluoride glasses doped with dysprosium oxide were prepared by melt-quenching technique with chemical composition 20La2O3:10CaO:69P2O5:1Dy2O3 and 20La2O3:10CaF2:69P2O5:1Dy2O3. The physical, optical and luminescence properties of the glass samples were studied to evaluate their potential to using as luminescence materials for solid-state lighting applications. The density, molar volume and refractive index of the glass samples were carried out. The optical and luminescence properties were studied by investigating absorption, excitation, and emission spectra of the glass samples. The absorption spectra were investigated in the UV-Vis-NIR region from 300 to 2000 nm. The excitation spectra observed under 574 nm emission wavelength showed the highest peak centered at 349 nm (6H15/2 → 6P7/2). The emission spectra, excited with 349 nm excitation wavelength showed two major peaks corresponding to 482 nm blue emission (4F9/2 → 6H15/2) and 574 nm yellow emission (4F9/2 → 6H13/2). The experimental lifetime were found to be 0.539 and 0.540 for oxide and oxyfluoride glass sample, respectively. The x,y color coordinates under 349 nm excitation wavelength were (0.38, 0.43) for both glass samples, that be plotted in white region of CIE 1931 chromaticity diagram. The CCT values obtained from the glass samples are 4204 K for oxide glass and 4228 K for oxyfluoride glass corresponding to the commercial cool white light (3100-4500 K). Judd-Ofelt theory had also been employed to obtain the J-O parameters (Ω2, Ω4 and Ω6), oscillator strength, radiative transition possibility, stimulated emission cross section and branching ratio. The Ω2 > Ω4 > Ω6 trend of J-O parameters of both glass samples may indicate the good quality of a glass host for using as optical device application. Temperature dependence of emission spectra was studied from 300 K to 10 K and found that the intensity of the emission peak was found to be increased with decreasing of the temperature. The results of the investigations in this work confirmed that the present Dy-doped lanthanum calcium phosphate oxide and oxyfluoride glasses perform high potential for using as efficient luminescence materials for solid-state lighting applications, especially for white LEDs. Furthermore, the oxyfluoride glass sample provides more luminescence potential than the oxide glass sample.

Reduced reactivity to air on HF-treated YBa2Cu3O(7-x)surfaces

NASA Technical Reports Server (NTRS)

Vasquez, R. P.; Hunt, B. D.; Foote, M. C.

1989-01-01

Treatment of YBa2Cu3O(7-x) films with a nonaqueous solution of HF in absolute ethanol results in the formation of an oxyfluoride with relative Y:Ba:Cu concentrations of 1:4:3 on the surface, as determined by X-ray photoelectron spectroscopy. The passivation properties of chemically treated films were tested by monitoring the growth of the high binding energy O 1s peak, associated with nonsuperconducting surface species, as a function of air exposure time, for both HF-treated and untreated films. The native oxyfluoride is shown to reduce the reactivity of the superconductor to air.

Method for fluorination of actinide fluorides and oxyfluorides using O/sub 2/F/sub 2/

DOEpatents

Eller, P.G.; Malm, J.G.; Penneman, R.A.

1984-08-01

The present invention relates generally to methods of fluorination and more particularly to the use of O/sub 2/F/sub 2/ for the preparation of actinide hexafluorides, and for the extraction of deposited actinides and fluorides and oxyfluorides thereof from reaction vessels. The experiments set forth hereinabove demonstrate that the room temperature or below use of O/sub 2/F/sub 2/ will be highly beneficial for the preparation of pure actinide hexafluorides from their respective tetrafluorides without traces of HF being present as occurs using other fluorinating agents: and decontamination of equipment previously exposed to actinides: e.g., walls, feed lines, etc.

A Stable, Narrow-Gap Oxyfluoride Photocatalyst for Visible-Light Hydrogen Evolution and Carbon Dioxide Reduction.

PubMed

Kuriki, Ryo; Ichibha, Tom; Hongo, Kenta; Lu, Daling; Maezono, Ryo; Kageyama, Hiroshi; Ishitani, Osamu; Oka, Kengo; Maeda, Kazuhiko

2018-05-30

Mixed anion compounds such as oxynitrides and oxychalcogenides are recognized as potential candidates of visible-light-driven photocatalysts since, as compared with oxygen 2p orbitals, p orbitals of less electronegative anion (e.g., N 3- , S 2- ) can form a valence band that has more negative potential. In this regard, oxyfluorides appear unsuitable because of the higher electronegativity of fluorine. Here we show an exceptional case, an anion-ordered pyrochlore oxyfluoride Pb 2 Ti 2 O 5.4 F 1.2 that has a small band gap (ca. 2.4 eV). With suitable modification of Pb 2 Ti 2 O 5.4 F 1.2 by promoters such as platinum nanoparticles and a binuclear ruthenium(II) complex, Pb 2 Ti 2 O 5.4 F 1.2 worked as a stable photocatalyst for visible-light-driven H 2 evolution and CO 2 reduction. Density functional theory calculations have revealed that the unprecedented visible-light-response of Pb 2 Ti 2 O 5.4 F 1.2 arises from strong interaction between Pb-6s and O-2p orbitals, which is enabled by a short Pb-O bond in the pyrochlore lattice due to the fluorine substitution.

Photoluminescence properties of Mn2+/Yb3+ co-doped oxyfluoride glasses for solar cells application

NASA Astrophysics Data System (ADS)

Yan, Ying; Chen, Zeng; Jia, Xiyang; Li, Shengjun

2018-01-01

Mn2+/Yb3+ co-doped oxyfluoride glasses were facilely synthesized in the SiO2-Al2O3-Na2O-CaF2 system. Partial crystallization processed during the preparation of the glasses, by which small amounts of CaF2 nano-crystals were formed. Under ultraviolet and blue (370-500 nm) light excitation, an efficient down-conversion involving the emission of near-infrared is realized in the Mn2+/Yb3+ co-doped oxyfluoride glasses. The near-infrared emission peaks mainly at 976 nm and secondarily at 1020 nm, which is a comfortable match with the band gap of c-Si. The variation in visible and near-infrared spectra and the decay curves of Mn2+:4T1 → 6A1 emission have been investigated to verify the possible energy transfer from Mn2+ ions to Yb3+ ions. On analyzing the energy transfer processes theoretically and experimentally, we propose that quantum cutting and down-shifting processes may occur simultaneously in the samples. We suggest that the Mn2+-Yb3+ co-doped materials can provide a novel direction to realize UV-Vis to NIR down-conversion for Si solar cells.

Infrared-to-visible conversion luminescence of Er 3+ ions in lead borate transparent glass-ceramics

NASA Astrophysics Data System (ADS)

Pisarski, Wojciech A.; Pisarska, Joanna; Lisiecki, Radosław; Grobelny, Łukasz; Dominiak-Dzik, Grażyna; Ryba-Romanowski, Witold

2009-10-01

Transparent glass-ceramics were successfully prepared during controlled heat treatment of lead borate glasses. The PbF 2 particles were dispersed into a borate glass matrix which was evidenced by X-ray diffraction analysis. The phase identification revealed that crystalline peaks can be related to the orthorhombic PbF 2 phase. Green up-conversion luminescence due to the 4S 3/2- 4I 15/2 transition of Er 3+ ions was registered. In comparison to the precursor glass the luminescence intensity was considerably higher, whereas the luminescence linewidth slightly decreased in the studied oxyfluoride transparent glass-ceramics. It indicated that a part of the trivalent erbium was incorporated into the PbF 2 crystalline phase.

Method for fluorination of actinide fluorides and oxyfluorides thereof using O.sub.2 F.sub.2

DOEpatents

Eller, Phillip G.; Malm, John G.; Penneman, Robert A.

1988-01-01

Method for fluorination of actinides and fluorides and oxyfluorides thereof using O.sub.2 F.sub.2 which generates actinide hexafluorides, and for removal of actinides and compounds thereof from surfaces upon which they appear as unwanted deposits. The fluorinating agent, O.sub.2 F.sub.2, has been observed to readily perform the above-described tasks at sufficiently low temperatures that there is virtually no damage to the containment vessels. Moreover, the resulting actinide hexafluorides are thereby not destroyed by high temperature reactions with the walls of the reaction vessel. Dioxygen difluoride is easily prepared, stored and transferred to the desired place of reaction.

Fluoride glass starting materials - Characterization and effects of thermal treatment

NASA Technical Reports Server (NTRS)

Chen, William; Dunn, Bruce; Shlichta, Paul; Neilson, George F.; Weinberg, Michael C.

1987-01-01

The production of heavy metal fluoride (HMF) glasses, and the effects of thermal treatments on the HMF glasses are investigated. ZrF4, BaF2, AlF3, LaF3, and NaF were utilized in the synthesis of zirconium-barium-lanthanum-aluminum-sodium fluoride glass. The purity of these starting materials, in particular ZrF4, is evaluated using XRD analysis. The data reveal that low temperature heating of ZrF4-H2O is effective in removing the water of hydration, but causes the production of ZrF4 and oxyfluorides; however, dehydration followed by sublimation results in the production of monoclinic ZrFe without water or oxyfluoride contaminants.

Method for fluorination of actinide fluorides and oxyfluorides thereof using O[sub 2]F[sub 2

DOEpatents

Eller, P.G.; Malm, J.G.; Penneman, R.A.

1988-11-08

Method is described for fluorination of actinides and fluorides and oxyfluorides thereof using O[sub 2]F[sub 2] which generates actinide hexafluorides, and for removal of actinides and compounds thereof from surfaces upon which they appear as unwanted deposits. The fluorinating agent, O[sub 2]F[sub 2], has been observed to readily perform the above-described tasks at sufficiently low temperatures that there is virtually no damage to the containment vessels. Moreover, the resulting actinide hexafluorides are thereby not destroyed by high temperature reactions with the walls of the reaction vessel. Dioxygen difluoride is easily prepared, stored and transferred to the desired place of reaction.

Optical transitions of Ho(3+) in oxyfluoride glasses and upconversion luminescence of Ho(3+)/Yb(3+)-codoped oxyfluoride glasses.

PubMed

Feng, Li; Wu, Yinsu

2015-05-05

Optical properties of Ho(3+)-doped SiO2-BaF2-ZnF2 glasses have been investigated on the basis of the Judd-Ofelt theory. Judd-Ofelt intensity parameters, radiative transition probabilities, fluorescence branching ratios and radiative lifetimes have been calculated for different glass compositions. Upconversion emissions were observed in Ho(3+)/Yb(3+)-codoped SiO2-BaF2-ZnF2 glasses under 980nm excitation. The effects of composition, concentration of the doping ions, and excitation pump power on the upconversion emissions were also systematically studied. Copyright © 2015 Elsevier B.V. All rights reserved.

Optical transitions of Tm3+ in oxyfluoride glasses and compositional and thermal effect on upconversion luminescence of Tm3+/Yb3+-codoped oxyfluoride glasses.

PubMed

Feng, Li; Wu, Yinsu; Liu, Zhuo; Guo, Tao

2014-01-24

Optical properties of Tm(3+)-doped SiO2-BaF2-ZnF2 glasses have been investigated on the basis of the Judd-Ofelt theory. Judd-Ofelt intensity parameters, radiative transition probabilities, fluorescence branching ratios and radiative lifetimes have been calculated for different glass compositions. Upconversion emissions were observed in Tm(3+)/Yb(3+)-codoped SiO2-BaF2-ZnF2 glasses under 980 nm excitation. The effects of composition, concentration of the doping ions, temperature, and excitation pump power on the upconversion emissions were also systematically studied. Copyright © 2013 Elsevier B.V. All rights reserved.

[Multiply upconversion emission in oxyfluoride ceramics].

PubMed

Xiao, Si-guo; Yang, Xiao-liang; Liu, Zhen-wei

2003-02-01

Oxyfluoride ceramics with the host composition of SiO2 and PbF2 have been prepared. X-ray diffraction analysis of the ceramics revealed that fluoride type beta-PbF2 solid solution regions are precipitated in the glass matrix. Rare earth ions in the beta-PbF2 solid solution show highly efficient upconversion performance due to the very small multi-phonon relaxation rates. Eight upconversion emission bands whose central wavelength are 846, 803, 665, 549, 523, 487, 456 and 411 nm have been observed when the sample was excited with 930 nm diode light. Four possible energy transfer processes between Er3+ and Yb3+ cause the electronic population of high energy level of Er3+ and realize the abound upconversion luminescence bands.

White light upconversion emissions in Er3+/Tm3+/Yb3+ tridoped oxyfluoride glass

NASA Astrophysics Data System (ADS)

Guan, Xiaoping; Xu, Wei; Zhu, Shuang; Song, Qiutong; Wu, Xijun; Liu, Hailong

2015-10-01

Rare earth ions doped glasses producing visible upconversion emissions are of great interest due to their potential applications in the photonics filed. In fact, practical application of upconversion emissions has been used to obtain color image displays and white light sources. However, there are few reports on the thermal effect on tuning the emission color of the RE doped materials. In this work, the Er3+/Tm3+/Yb3+ tridoped oxyfluoride glasses were prepared through high temperature solid-state method. Under a 980 nm diode laser excitation, the upconversion emissions from the samples were studied. At room-temperature, bright white luminescence, whose CIE chromaticity coordinate was about (0.28, 0.31), can be obtained when the excitation power was 120 mW. The emission color was changed by varying the intensity ratios between RGB bands, which are strongly dependent on the rare earth ions concentration. The temperature dependent color emissions were also investigated. As temperature increased, the intensities for the emission bands presented different decay rates, finally resulting in the changing of the CIE coordinate. When the temperature was 573 K, white light with color coordinate of (0.31, 0.33) was achieved, which matches well with the white reference (0.33, 0.33). The color tunability, high quality of white light and intense emission intensity make the transparent oxyfluoride glasses excellent candidates for applications in solid-state lighting.

Development of ytterbium-doped oxyfluoride glasses for laser cooling applications.

PubMed

Krishnaiah, Kummara Venkata; de Lima Filho, Elton Soares; Ledemi, Yannick; Nemova, Galina; Messaddeq, Younes; Kashyap, Raman

2016-02-26

Oxyfluoride glasses doped with 2, 5, 8, 12, 16 and 20 mol% of ytterbium (Yb(3+)) ions have been prepared by the conventional melt-quenching technique. Their optical, thermal and thermo-mechanical properties were characterized. Luminescence intensity at 1020 nm under laser excitation at 920 nm decreases with increasing Yb(3+) concentration, suggesting a decrease in the photoluminescence quantum yield (PLQY). The PLQY of the samples was measured with an integrating sphere using an absolute method. The highest PLQY was found to be 0.99(11) for the 2 mol% Yb(3+): glass and decreases with increasing Yb(3+) concentration. The mean fluorescence wavelength and background absorption of the samples were also evaluated. Upconversion luminescence under 975 nm laser excitation was observed and attributed to the presence of Tm(3+) and Er(3+) ions which exist as impurity traces with YbF3 starting powder. Decay curves for the Yb(3+): (2)F5/2 → (2)F7/2 transition exhibit single exponential behavior for all the samples, although lifetime decrease was observed for the excited level of Yb(3+) with increasing Yb(3+) concentration. Also observed are an increase in the PLQY and a slight decrease in lifetime with increasing the pump power. Finally, the potential of these oxyfluoride glasses with high PLQY and low background absorption for laser cooling applications is discussed.

Development of ytterbium-doped oxyfluoride glasses for laser cooling applications

PubMed Central

Krishnaiah, Kummara Venkata; Soares de Lima Filho, Elton; Ledemi, Yannick; Nemova, Galina; Messaddeq, Younes; Kashyap, Raman

2016-01-01

Oxyfluoride glasses doped with 2, 5, 8, 12, 16 and 20 mol% of ytterbium (Yb3+) ions have been prepared by the conventional melt-quenching technique. Their optical, thermal and thermo-mechanical properties were characterized. Luminescence intensity at 1020 nm under laser excitation at 920 nm decreases with increasing Yb3+ concentration, suggesting a decrease in the photoluminescence quantum yield (PLQY). The PLQY of the samples was measured with an integrating sphere using an absolute method. The highest PLQY was found to be 0.99(11) for the 2 mol% Yb3+: glass and decreases with increasing Yb3+ concentration. The mean fluorescence wavelength and background absorption of the samples were also evaluated. Upconversion luminescence under 975 nm laser excitation was observed and attributed to the presence of Tm3+ and Er3+ ions which exist as impurity traces with YbF3 starting powder. Decay curves for the Yb3+: 2F5/2 → 2F7/2 transition exhibit single exponential behavior for all the samples, although lifetime decrease was observed for the excited level of Yb3+ with increasing Yb3+ concentration. Also observed are an increase in the PLQY and a slight decrease in lifetime with increasing the pump power. Finally, the potential of these oxyfluoride glasses with high PLQY and low background absorption for laser cooling applications is discussed. PMID:26915817

Synthesis and structure of a new layered oxyfluoride Sr{sub 2}ScO{sub 3}F with photocatalytic property

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

Wang, Yongkun; Tang, Kaibin, E-mail: kbtang@ustc.edu.cn; Zhu, Baichuan

2015-05-15

Highlights: • A new oxyfluoride compound Sr{sub 2}ScO{sub 3}F was prepared by a solid state route. • The structure of this compound was determined by GSAS program based on XRD data. • The photocatalytic property was investigated under UV irradiation. - Abstract: A new Ruddlesden–Popper type scandium oxyfluoride, Sr{sub 2}ScO{sub 3}F, was synthesized by a conventional solid state reaction route. The detailed structure of Sr{sub 2}ScO{sub 3}F was investigated using X-ray diffraction (XRD) and selected area electron diffraction (SAED). The disorder distribution pattern of fluorine anions was determined by the {sup 19}F nuclear magnetic resonance (NMR) spectrum. The compound crystallizesmore » in a K{sub 2}NiF{sub 4}-type tetragonal structure (space group I4/mmm) with O/F anions disordered over the apical sites of the perovskite-type Sc(O,F){sub 6} octahedron layers interleaved with strontium cations. Ultraviolet–visible (UV–vis) diffuse reflection spectrum of the prepared Sr{sub 2}ScO{sub 3}F indicates that it has an absorption in the UV–vis region. The photocatalytic activity of Sr{sub 2}ScO{sub 3}F was further investigated, showing an effective photodegradation of Rhodamine-B (RB) within 2 h under UV light irradiation.« less

Structure, stability, and photoluminescence in the anti-perovskites Na{sub 3}W{sub 1−x}Mo{sub x}O{sub 4}F (0≤x≤1)

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

Sullivan, Eirin, E-mail: esulliv@ilstu.edu; Avdeev, Maxim; Blom, Douglas A.

2015-10-15

Single-phase ordered oxyfluorides Na{sub 3}WO{sub 4}F, Na{sub 3}MoO{sub 4}F and their mixed members Na{sub 3}W{sub 1−x}Mo{sub x}O{sub 4}F can be prepared via facile solid state reaction of Na{sub 2}MO{sub 4}·2H{sub 2}O (M=W, Mo) and NaF. Phases produced from incongruent melts are metastable, but lower temperatures allow for a facile one-step synthesis. In polycrystalline samples of Na{sub 3}W{sub 1−x}Mo{sub x}O{sub 4}F, the presence of Mo stabilizes the structure against decomposition to spinel phases. Photoluminescence studies show that upon excitation with λ=254 nm and λ=365 nm, Na{sub 3}WO{sub 4}F and Na{sub 3}MoO{sub 4}F exhibit broad emission maxima centered around 485 nm. Thesemore » materials constitute new members of the family of self-activating ordered oxyfluoride phosphors with anti-perovskite structures which are amenable to doping with emitters such as Eu{sup 3+}. - Graphical abstract: Directed synthesis of the ordered oxyfluorides Na{sub 3}W{sub 1−x}Mo{sub x}O{sub 4}F (0≤x≤1) has shown that a complete solid solution is attainable and provides the first example of photoluminescence in these materials. - Highlights: • Na{sub 3}W{sub 1−x}Mo{sub x}O{sub 4}F is a complete solid solution with hexagonal anti-perovskite structure. • The presence of even small amounts of Mo stabilizes the structure against decomposition. • Na{sub 3}W{sub 1−x}Mo{sub x}O{sub 4}F has broad emissions centered ≈485 nm (λ{sub ex}=254 nm and λ{sub ex}=365 nm). • These materials constitute a new family of self-activated oxyfluoride phosphors. • Na{sub 3}W{sub 1−x}Mo{sub x}O{sub 4}F materials are amenable to doping with emitters such as Eu{sup 3+}.« less

Cubic to tetragonal phase transition of Tm{sup 3+} doped nanocrystals in oxyfluoride glass ceramics

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

Li, Yiming; Fu, Yuting; Shi, Yahui

2016-02-15

Tm{sup 3+} ions doped β-PbF{sub 2} nanocrystals in oxyfluoride glass ceramics with different doping concentrations and thermal temperatures are prepared by a traditional melt-quenching and thermal treatment method to investigate the structure and the phase transition of Tm{sup 3+} doped nanocrystals. The structures are characterized by X-ray diffraction Rietveld analysis and confirmed with numerical simulation. The phase transitions are proved further by the emission spectra. Both of the doping concentration and thermal temperature can induce an O{sub h} to D{sub 4h} site symmetry distortion and a cubic to tetragonal phase transition. The luminescence of Tm{sup 3+} doped nanocrystals at 800more » nm was modulated by the phase transition of the surrounding crystal field.« less

Synthesis and structural characterization of the hexagonal anti-perovskite Na{sub 2}CaVO{sub 4}F

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

Green, Robert L., E-mail: rgreen@flpoly.org; Avdeev, Maxim; School of Chemistry, The University of Sydney, Sydney, NSW 2006

The structural details of the ordered hexagonal oxyfluoride Na{sub 2}CaVO{sub 4}F prepared by solid-state synthesis using stoichiometric amounts of V{sub 2}O{sub 5}, CaCO{sub 3}, Na{sub 2}CO{sub 3} and NaF were characterized using high-resolution neutron powder diffraction. The structural changes between 25 °C and 750 °C revealed that the two structural subunits in this material behave different when heated: there is an expansion of the face-shared FNa{sub 4}Ca{sub 2} octahedra while the VO{sub 4} tetrahedra due to increased thermal disorder reveal marginal bond contractions. Bond valences and the global instability index point to significant structural disorder at 750 °C. - Graphicalmore » abstract: The structure of the novel oxyfluoride Na{sub 2}CaVO{sub 4}F is studied at room temperature and high-temperatures. The structure can be viewed as layers of compression and elongation of polyhedral subunits, which change as a function of temperature. - Highlights: • The novel oxyfluoride, Na{sub 2}CaVO{sub 4}F, is synthesized via solid-state method. • High-resolution neutron diffraction data is used to analyze the structure of Na{sub 2}CaVO{sub 4}F. • Structural subunits exhibit expansion and contraction with increasing temperature. • Higher temperatures increase instability within the structure of Na{sub 2}CaVO{sub 4}F.« less

Hydrothermal synthesis of (C6N2H14)2(UVI2UIVO4F12), a mixed-valent one-dimensional uranium oxyfluoride.

PubMed

Allen, S; Barlow, S; Halasyamani, P S; Mosselmans, J F; O'Hare, D; Walker, S M; Walton, R I

2000-08-21

A new hybrid organic-inorganic mixed-valent uranium oxyfluoride, (C6N2H14)2(U3O4F12), UFO-17, has been synthesized under hydrothermal conditions using uranium dioxide as the uranium source, hydrofluoric acid as mineralizer, and 1,4-diazabicyclo[2.2.2]octane as template. The single-crystal X-ray structure was determined. Crystals of UFO-17 belonged to the orthorhombic space group Cmcm (no. 63), with a = 14.2660(15) A, b = 24.5130(10) A, c = 7.201(2) A, and Z = 4. The structure reveals parallel uranium-containing chains of two types: one type is composed of edge-sharing UO2F5 units; the other has a backbone of edge-sharing UF8 units, each sharing an edge with a pendant UO2F5 unit. Bond-valence calculations suggest the UF8 groups contain UIV, while the UO2F5 groups contain UVI. EXAFS data give results consistent with the single-crystal X-ray structure determination, while comparison of the uranium LIII-edge XANES of UFO-17 with that of related UIV and UVI compounds supports the oxidation-state assignment. Variable-temperature magnetic susceptibility measurements on UFO-17 and a range of related hybrid organic-inorganic uranium(IV) and uranium(VI) fluorides and oxyfluorides further support the formulation of UFO-17 as a mixed-valent UIV/UVI compound.

Experimental and theoretical methods to study structural phase transition mechanisms in K{sub 3}WO{sub 3}F{sub 3} oxyfluoride

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

Krylov, A.S., E-mail: shusy@iph.krasn.ru; Sofronova, S.N.; Kolesnikova, E.M.

2014-10-15

The results of structural phase transitions mechanisms study in K{sub 3}WO{sub 3}F{sub 3}oxyfluoride are represented by different experimental and theoretical methods. The structural phase transition anomalies at T{sub 1}=452 K and T{sub 2}=414 K of Raman and IR spectra have been analyzed. Using vibrational spectroscopy methods, the NMR-experiment has been done to clarify the nature of found phase transitions: displacive types or order-disorder types. The model of “disordered” crystal was proposed, and the results of lattice dynamics calculation in frameworks of the generalized Gordon–Kim method of ordered (R3) and “disordered” crystals were compared. The high pressure phases were studied bymore » the Raman technique too. - Graphical abstract: (1) Two possible configuration of octahedra. (2). All phases Raman lines of octahedra. (3) All phases IR lines of octahedra. (4) NMR spectra of all phases. - Highlights: • The results of study oxyfluoride K{sub 3}WO{sub 3}F{sub 3} are represented by Raman, IR, NMR technique. • The high pressure phases were studied by the Raman technique. • The anionic octahedra [WO{sub 3}F{sub 3}]{sup 3−} are not ordered below the both phase transitions. • The ferroelectric phase is realized due to the shift of atoms without F/O ordering. • Both of found phase transitions are close to the second order.« less

Radioluminescence and optical studies of gadolinium calcium phosphate oxyfluoride glasses doped with Sm3+

NASA Astrophysics Data System (ADS)

Meejitpaisan, P.; Insiripong, S.; Kedkaew, C.; Kim, H. J.; Kaewkhao, J.

2017-08-01

Sm3+-doped gadolinium calcium phosphate oxyfluoride glasses have been synthesized and investigated their optical, photo and radioluminescence properties. The glasses were prepared by melt quenching technique at 1400 °C. The characteristic absorption bands of Sm3+ ions originating from the 6H5/2 ground state and occurring absorbed photon in visible light (VIS) and near-infrared (NIR) region with clearly observed from absorption spectra. From the photoluminescence (PL), the glasses showed the emission at 561 (4G5/2→6H5/2), 598 (4G5/2→6H7/2), 644 (4G5/2→6H9/2) and 705 nm (4G5/2→6H11/2). The radioluminescence (RL), emission spectra were corresponding to those from PL measurements. From RL measurement, the integral scintillation efficiency of developed glass was determined at 43% when compared with BGO crystal.

Structural study of VO {sub x} doped aluminium fluoride and aluminium oxide catalysts

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

Scheurell, Kerstin; Scholz, Gudrun; Kemnitz, Erhard

The structural properties of vanadium doped aluminium oxyfluorides and aluminium oxides, prepared by a modified sol-gel synthesis route, were thoroughly investigated. The influence of the preparation technique and the calcination temperature on the coordination of vanadium, aluminium and fluorine was analysed by different spectroscopic methods such as Raman, MAS NMR and ESR spectroscopy. In all samples calcined at low temperatures (350 deg. C), vanadium coexists in two oxidation states V{sup IV} and V{sup V}, with V{sup IV} as dominating species in the vanadium doped aluminium oxyfluorides. In the fluoride containing solids aluminium as well as vanadium are coordinated by fluorinemore » and oxygen. Thermal annealing of 800 deg. C leads to an extensive reorganisation of the original matrices and to the oxidation of V{sup IV} to V{sup V} in both systems. - Graphical abstract: Structure model for VO {sub x} doped aluminium oxide.« less

Transparent Glass-Ceramics Produced by Sol-Gel: A Suitable Alternative for Photonic Materials.

PubMed

Gorni, Giulio; Velázquez, Jose J; Mosa, Jadra; Balda, Rolindes; Fernández, Joaquin; Durán, Alicia; Castro, Yolanda

2018-01-30

Transparent glass-ceramics have shown interesting optical properties for several photonic applications. In particular, compositions based on oxide glass matrices with fluoride crystals embedded inside, known as oxyfluoride glass-ceramics, have gained increasing interest in the last few decades. Melt-quenching is still the most used method to prepare these materials but sol-gel has been indicated as a suitable alternative. Many papers have been published since the end of the 1990s, when these materials were prepared by sol-gel for the first time, thus a review of the achievements obtained so far is necessary. In the first part of this paper, a review of transparent sol-gel glass-ceramics is made focusing mainly on oxyfluoride compositions. Many interesting optical results have been obtained but very little innovation of synthesis and processing is found with respect to pioneering papers published 20 years ago. In the second part we describe the improvements in synthesis and processing obtained by the authors during the last five years. The main achievements are the preparation of oxyfluoride glass-ceramics with a much higher fluoride crystal fraction, at least double that reported up to now, and the first synthesis of NaGdF₄ glass-ceramics. Moreover, a new SiO₂ precursor was introduced in the synthesis, allowing for a reduction in the treatment temperature and favoring hydroxyl group removal. Interesting optical properties demonstrated the incorporation of dopant ions in the fluoride crystals, thus obtaining crystal-like spectra along with higher efficiencies with respect to xerogels, and hence demonstrating that these materials are a suitable alternative for photonic applications.

The structure of Er3+-doped oxy-fluoride transparent glass-ceramics studied by Raman scattering

NASA Astrophysics Data System (ADS)

Tikhomirov, V. K.; Seddon, A. B.; Ferrari, M.; Montagna, M.; Santos, L. F.; Almeida, R. M.

2003-11-01

We show that the structure of transparent oxy-fluoride glass-ceramics formed by heat treatment of glasses of typical composition 32(SiO2):9(AlO1.5):31.5(CdF2):18.5(PbF2): 5.5(ZnF2):3.5(ErF3) mol% consists of ~ 12 nm diameter, Er3+-doped, β-PbF2 nano-crystals embedded in a silica-based glass network and connected to it via non-bridging O and F anions, or fluorine linkages such as Pb-F-Cd and Pb-F-Zn. It is proposed that the glass network structure is mostly chain-like and dominated by Si(O,F)4 tetrahedra with two bridging O and two non-bridging O and/or F atoms (Q2 units). SiO4 tetrahedra with zero and one bridging O (Q0 and Q1 units, respectively) are also present in the glass structure, in the approximate proportion Q0:Q1:Q2 = 1:1:3, a characteristic which appears to be of primary importance. The flexible, chain-like glass-network, with many broken bonds, results in easy accommodation of the Er3+-doped PbF2 nano-crystals, which are grown by heat-treatment of the precursor glass. The boson peak in the Raman spectrum of the precursor glass decreases in intensity upon ceramming and is partly converted to narrow crystalline peaks at lower frequency, consistent with the precipitation of PbF2 crystalline nano-particles. It is suggested that the boson peak involves localized vibrations of broken or stretched Pb-F bonds. The mean free path for these vibrations increases with ceramming, which involves partial crystallization of the glass network, resulting in a shift of the boson peak vibrations to lower-frequency crystalline peaks.

Low temperature synthesis of LnOF rare-earth oxyfluorides through reaction of the oxides with PTFE

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

Dutton, S.E., E-mail: sdutton@princeton.edu; Hirai, D.; Cava, R.J.

2012-03-15

Highlights: Black-Right-Pointing-Pointer Low temperature synthesis of LnOF rare-earth oxyfluorides from Ln{sub 2}O{sub 3} and PTFE (CF{sub 2}). Black-Right-Pointing-Pointer Rhombohedral LnOF is the major phase and forms as nanocrystals, 29-103 nm. Black-Right-Pointing-Pointer Expected lanthanide contraction observed in lattice parameters and bond lengths. Black-Right-Pointing-Pointer TbOF orders antiferromagnetically at 10 K and has a metamagnetic transition at 1.8 T. Black-Right-Pointing-Pointer GdOF orders antiferromagnetically at 5 K, other LnOF are paramagnetic. -- Abstract: A low temperature solid-state synthesis route, employing polytetrafluoroethylene (PTFE) and the rare-earth oxides, for the formation of the LnOF rare-earth oxyfluorides (Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Tb,more » Dy, Ho, Er), is reported. With the exception of LaOF, which forms in a tetragonal variant, rhomobohedral LnOF is found to be the major product of the reaction. In the case of PrOF, a transition from the rhombohedral to the cubic fluorite phase is observed on heating in air to 500 Degree-Sign C. X-ray diffraction shows the expected lanthanide contraction in the lattice parameters and bond lengths. Magnetic susceptibility measurements show antiferromagnetic-like ordering in TbOF, T{sub m} = 10 K, with a metamagnetic transition at a field {mu}{sub 0}H{sub t} = 1.8 T at 2 K. An antiferromagnetic transition, T{sub N} = 4 K, is observed in GdOF. Paramagnetic behavior is observed above 2 K in PrOF, NdOF, DyOF, HoOF and ErOF. The magnetic susceptibility of EuOF is characteristic of Van Vleck paramagnetism.« less

Novel high volumetric energy density nanostructured electrode materials for biomedical applications

NASA Astrophysics Data System (ADS)

Tong, Wei

A definitive focus is being made to develop cathode materials of higher energy and good power for primary and rechargeable lithium batteries upon the development of implantable biomedical devices (cardiac defibrillators). In this thesis, novel electroactive nanostructured silver metal oxyfluoride perovskites, Ag1+3Mo6+(O3F 3) and Ag1+3Nb5+(O2F 4) have been successfully synthesized by a mechanochemical reaction. The formation of these perovskites was investigated throughout the Ag-Mo / Nb composition range with the use of either Ag1+ or Ag 2+ in the form of AgF and AgF2 as the reactant, respectively. The compositional study combined with XRD and extensive Raman investigation was utilized to determine structure and cation distribution and infer oxidation state. An electrochemical characterization of these silver metal oxyfluoride perovskite positive electrodes for Li batteries was investigated for the first time as a function of synthesis condition, stoichiometry and effect of Mo and Ag derived second phases. A detailed in-situ electrochemical study by XAS, Raman and XRD was performed, revealing a 3 electron silver displacement or conversion reaction at > 3 V and a 2 electron reduction of Mo6+ to Mo4+ in the region < 3 V. To further improve the rate capability of silver metal oxyfluorides, metallic Ag2F phase has been successfully synthesized through the mechanochemical reaction of Ag and AgF. Its unique metallic character within Ag layers lead to a very good electronic conductivity (7.89x10 -2 S/cm). The efficacy of SMOF composites consisting of conducting matrix (carbon black, Ag2F and Ag phase) for lithium battery was investigated through discharge rate studies. Results indicated that Ag 2F phase could be utilized as an alternative conductive additive with exceptional density.

Transparent Glass-Ceramics Produced by Sol-Gel: A Suitable Alternative for Photonic Materials

PubMed Central

Gorni, Giulio; Mosa, Jadra; Balda, Rolindes; Fernández, Joaquin; Durán, Alicia; Castro, Yolanda

2018-01-01

Transparent glass-ceramics have shown interesting optical properties for several photonic applications. In particular, compositions based on oxide glass matrices with fluoride crystals embedded inside, known as oxyfluoride glass-ceramics, have gained increasing interest in the last few decades. Melt-quenching is still the most used method to prepare these materials but sol-gel has been indicated as a suitable alternative. Many papers have been published since the end of the 1990s, when these materials were prepared by sol-gel for the first time, thus a review of the achievements obtained so far is necessary. In the first part of this paper, a review of transparent sol-gel glass-ceramics is made focusing mainly on oxyfluoride compositions. Many interesting optical results have been obtained but very little innovation of synthesis and processing is found with respect to pioneering papers published 20 years ago. In the second part we describe the improvements in synthesis and processing obtained by the authors during the last five years. The main achievements are the preparation of oxyfluoride glass-ceramics with a much higher fluoride crystal fraction, at least double that reported up to now, and the first synthesis of NaGdF4 glass-ceramics. Moreover, a new SiO2 precursor was introduced in the synthesis, allowing for a reduction in the treatment temperature and favoring hydroxyl group removal. Interesting optical properties demonstrated the incorporation of dopant ions in the fluoride crystals, thus obtaining crystal-like spectra along with higher efficiencies with respect to xerogels, and hence demonstrating that these materials are a suitable alternative for photonic applications. PMID:29385706

Pressure-Driven Spin Crossover Involving Polyhedral Transformation in Layered Perovskite Cobalt Oxyfluoride

PubMed Central

Tsujimoto, Yoshihiro; Nakano, Satoshi; Ishimatsu, Naoki; Mizumaki, Masaichiro; Kawamura, Naomi; Kawakami, Takateru; Matsushita, Yoshitaka; Yamaura, Kazunari

2016-01-01

We report a novel pressure-driven spin crossover in layered cobalt oxyfluoride Sr2CoO3F with a distorted CoO5 square pyramid loosely bound with a fluoride ion. Upon increasing pressure, the spin state of the Co(III) cation gradually changes from a high spin state (S = 2) to a low spin state (S = 0) accompanied by a anomalously large volume contraction (bulk modulus, 76.8(5) GPa). The spin state change occurs on the CoO5 pyramid in a wide pressure range, but the concomitant gradual shrinkage of the Co–F bond length with pressure gives rise to a polyhedral transformation to the CoO5F octahedron without a structural phase transition, leading to the full conversion to the LS state at 12 GPa. The present results provide new effective strategy to fine-tune electronic properties of mixed anion systems by controlling the covalency in metal-ligand bonds under pressure. PMID:27805031

Up-conversion luminescence of Er3+ ions in lead-free germanate glasses under 800 nm and 980 nm cw diode laser excitation

NASA Astrophysics Data System (ADS)

Janek, J.; Lisiecki, R.; Ryba-Romanowski, W.; Pisarska, J.; Pisarski, W. A.

2017-12-01

Up-conversion luminescence spectra of Er3+ ions in multicomponent oxyfluoride glasses GeO2 - BaO - BaF2 - Ga2O3 - Er2O3 were examined. It was found that the up-conversion luminescence spectra of Er3+ are dependent on pumping wavelengths. The spectra recorded upon the excitation at 800 nm contained an intense green up-conversion luminescence corresponding to the 2H11/2,4S3/2 → 4I15/2 transitions and a very weak red luminescence related to the 4F9/2 - 4I15/2 transition. In spectra recorded upon 980 nm excitation the contribution of the red luminescence was markedly higher. The interaction mechanisms involved in up-conversion processes are proposed and observed dependence of intensity of up-converted luminescence on excitation power is discussed. The experimental results suggest that Er3+ singly doped lead-free oxyfluoride germanate glass is useful for up-conversion luminescence applications.

Clean synthesis of YOF:Er3+, Yb3+ upconversion colloidal nanoparticles in water through liquid phase pulsed laser ablation for imaging applications

NASA Astrophysics Data System (ADS)

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

2017-10-01

Upconversion luminescent nanomaterials have great outlook towards imaging applications. These materials have high chemical and thermal stability, low auto fluorescence, high photo stability and IR excitation does not cause photo damage to living cells and penetrate deeply into tissue. Most of the reported nanoparticles are synthesized through chemical methods in which surface modification is needed for dispersing nanoparticles in water. In this paper we report clean and simple synthesis of upconversion luminescent yttrium oxyfluoride (YOF) nanoparticles through laser ablation in deionized water. YOF:Er3+, Yb3+ pellets were used for ablation. Er3+ is the emission centre Yb3+ is the sensitizer. Obtained colloidal solution is transparent to day light and showing red emission on exciting with 980 nm IR laser. By controlling ablation parameters particles of size less than 10 nm dispersed uniformly in water can be obtained through this surfactant free method. The synthesized nanoparticles can be used for cell imaging.

Comparison of Erosion Behavior and Particle Contamination in Mass-Production CF4/O2 Plasma Chambers Using Y2O3 and YF3 Protective Coatings

PubMed Central

Lin, Tzu-Ken; Wang, Wei-Kai; Huang, Shih-Yung; Tasi, Chi-Tsung

2017-01-01

Yttrium fluoride (YF3) and yttrium oxide (Y2O3) protective coatings prepared using an atmospheric plasma spraying technique were used to investigate the relationship between surface erosion behaviors and their nanoparticle generation under high-density plasma (1012–1013 cm−3) etching. As examined by transmission electron microscopy, the Y2O3 and YF3 coatings become oxyfluorinated after exposure to the plasma, wherein the yttrium oxyfluoride film formation was observed on the surface with a thickness of 5.2 and 6.8 nm, respectively. The difference in the oxyfluorination of Y2O3 and YF3 coatings could be attributed to Y–F and Y–O bonding energies. X-ray photoelectron spectroscopy analyses revealed that a strongly fluorinated bonding (Y–F bond) was obtained on the etched surface of the YF3 coating. Scanning electron microscopy and energy dispersive X-ray diffraction analysis revealed that the nanoparticles on the 12-inch wafer are composed of etchant gases and Y2O3. These results indicate that the YF3 coating is a more erosion-resistant material, resulting in fewer contamination particles compared with the Y2O3 coating. PMID:28708079

Formation of nanostructures in Eu3+ doped glass-ceramics: an XAS study.

PubMed

Pellicer-Porres, J; Segura, A; Martínez-Criado, G; Rodríguez-Mendoza, U R; Lavín, V

2013-01-16

We describe the results of x-ray absorption experiments carried out to deduce structural and chemical information in Eu(3+) doped, transparent, oxyfluoride glass and nanostructured glass-ceramic samples. The spectra were measured at the Pb and Eu-L(III) edges. The Eu environment in the glass samples is observed to be similar to that of EuF(3). Complementary x-ray diffraction experiments show that thermal annealing creates β-PbF(2) type nanocrystals. X-ray absorption indicates that Eu ions act as seeds in the nanocrystal formation. There is evidence of interstitial fluorine atoms around Eu ions as well as Eu dimers. X-ray absorption at the Pb-L(III) edge shows that after the thermal treatment most lead atoms form a PbO amorphous phase and that only 10% of the lead atoms remain available to form β-PbF(2) type nanocrystals. Both x-ray diffraction and absorption point to a high Eu content in the nanocrystals. Our study suggests new approaches to the oxyfluoride glass-ceramic synthesis in order to further improve their properties.

Spectroscopic properties of Nd3+ doped transparent oxyfluoride glass ceramics.

PubMed

Yu, Yunlong; Chen, Daqin; Ma, En; Wang, Yuansheng; Hu, Zhongjian

2007-07-01

In this paper, the spectroscopic properties of Nd(3+) doped transparent oxyfluoride glass ceramics containing LaF(3) nano-crystals were systematically studied. The formation and distribution of LaF(3) nano-crystals in the glass matrix were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Based on Judd-Ofelt theory, the intensity parameters Omega(t) (t=2, 4, 6), spontaneous emission probability, radiative lifetime, radiative quantum efficiency, width of the emission line and stimulated emission cross-section of Nd(3+) were evaluated. Particularly, the effect of Nd(3+) doping level on them was discussed. With the increase of Nd(3+) concentration in the glass ceramic, the experimental luminescence lifetime, radiative quantum efficiency and stimulated emission cross-section vary from 353.4 micros, 78.3% and 1.86 x 10(-20)cm(2) to 214.7 micros, 39.9% and 1.52 x 10(-20)cm(2), respectively. The comparative study of Nd(3+) spectroscopic parameters in different hosts suggests that the investigated glass ceramic system is potentially applicable as laser materials for 1.06 microm emission.

T-p phase diagrams and the barocaloric effect in materials with successive phase transitions

NASA Astrophysics Data System (ADS)

Gorev, M. V.; Bogdanov, E. V.; Flerov, I. N.

2017-09-01

An analysis of the extensive and intensive barocaloric effect (BCE) at successive structural phase transitions in some complex fluorides and oxyfluorides was performed. The high sensitivity of these compounds to a change in the chemical pressure allows one to vary the succession and parameters of the transformations (temperature, entropy, baric coefficient) over a wide range and obtain optimal values of the BCE. A comparison of different types of schematic T-p phase diagrams with the complicated T( p) dependences observed experimentally shows that in some ranges of temperature and pressure the BCE in compounds undergoing successive transformations can be increased due to a summation of caloric effects associated with distinct phase transitions. The maximum values of the extensive and intensive BCE in complex fluorides and oxyfluorides can be realized at rather low pressure (0.1-0.3 GPa). In a narrow temperature range around the triple points conversion from conventional BCE to inverse BCE is observed, which is followed by a gigantic change of both \\vertΔ S_BCE\\vert and \\vertΔ T_AD\\vert .

Structures and electron affinity of XO30,-, XOF40,- and XO2F20,- (X = P, As, Sb, Bi): a theoretical study of novel superhalogen formulae and exceptions of superhalogen formulae

NASA Astrophysics Data System (ADS)

Yang, Yi-Fan; Cui, Zhong-Hua; Ding, Yi-Hong

2015-03-01

Most superhalogen species are in the form of oxides or halides. To enrich the family of superhalogen species, herein, we investigated the structures and electron affinity (EA) values of higher group 15 elements (X = P, As, Sb, Bi) oxyfluoride species XO30,-, XOF40,- and XO2F20,-, at the CCSD(T)/aug-cc-pVTZ-pp & aug-cc-pVTZ //B3LYP/aug-cc-pVTZ-pp & aug-cc-pVTZ levels (aug-cc-pVTZ-pp for X = Sb and Bi). Some oxyfluoride species, i.e., PO2F20,-, AsO2F20,-, SbO2F20,-, POF40,-, AsOF40,-, SbOF40,- and BiOF40,-, were found to possess higher EA (VDE: 5.0-6.2 eV; ADE: 4.5-5.5 eV) than halogens (F: 3.4 eV; Cl: 3.6 eV). Thus, we recommended that the oxyfluorides in the form of XO2F20,- and XOF40,- should be considered as potential superhalogens, which have not been considered previously. Surprisingly, we showed that BiO3 and BiO2F2, in superhalogen formulae, possess a high vertical detachment energy (VDE) yet a low adiabatic detachment energy (ADE). This is in marked contrast to the previously reported superhalogens, which generally contain both the high VDE and high ADE values. It is the first report about exceptions of superhalogen formulae. These findings revealed that for the analogous main-group compounds with the same structural formula, the difference in the metallic property of the core element could lead to the significant difference in the ground structures of either the anionic or neutral structures, which would result in the much differed superhalogen features.

White light upconversion emission in Yb3+/ Er3+/ Tm3+ codoped oxy-fluoride lithium tungsten tellurite glass ceramics

NASA Astrophysics Data System (ADS)

Ansari, Ghizal F.; Mahajan, S. K.

2012-02-01

The bright white upconversion emission ( tri-colour UC) is generated in Er/Tm/Yb tri -doped oxy-fluoride lithium tungsten tellurite (TWLOF)glass ceramics containing crystalline phase LiYbF4 under the excitation of 980nm laser diode. The most appropriate combination of rare-earth ions (2mol% YbF3 1mol% ErF3 and 1mol%TmF3 )of glass ceramic sample has been determined to tune the primary colour (RGB and generate white light emission. By varying the pump power, intense and weak blue (487nm, 437nm), green (525nm and 545nm) and red (662nm) emission are simultaneously observed at room temperature. The dependence of upconversion emission intensity suggest that a theephoton process is responsible for the blue emission of Tm3+ ions and red emission due to both Tm3+ and Er3+ ions , while green emission originated from two photon processes in Er3+ ions. Also tri colour upconvesion and energy transfer in this glass ceramics sample were studied under 808nm laser diode excitation. The Upconversion mechanisms and Tm3+ ions plays role of both emitter and activator (transfer energy to Er) were discussed.

Freestanding NiFe Oxyfluoride Holey Film with Ultrahigh Volumetric Capacitance for Flexible Asymmetric Supercapacitors.

PubMed

Liang, Kun; Marcus, Kyle; Yang, Zhenzhong; Zhou, Le; Pan, Hao; Bai, Yuanli; Du, Yingge; Engelhard, Mark H; Yang, Yang

2018-01-01

In this work, a freestanding NiFe oxyfluoride (NiFeOF) holey film is prepared by electrochemical deposition and anodic treatments. With the combination of good electrical conductivity and holey structure, the NiFeOF holey film offers superior electrochemical performance with maximum specific capacitance of 670 F cm -3 (134 mF cm -2 ), due to the following reasons: (i) The residual metal alloy framework can be used as the current collector to improve electrode conductivity. Moreover, the as-prepared freestanding NiFeOF holey film can be used as a supercapacitor electrode without reliance on binders and other additives. The residual metal alloy framework and binder-free electrode effectively reduce electrode resistance, thus improving electron transport. (ii) The highly interconnected holey structure and hierarchical pore distribution provide a high specific surface area to improve electron transport, enhancing rapid ion transport, and mitigating diffusion limitations throughout the holey film. (iii) The excellent mechanical characteristics facilitate flexibility and cyclability related performance. Additionally, the NiFeOF holey film presents exceptional electrochemical performance, showing that it is a promising alternative for small/microsize electronic devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrochemical fluorination of La(2)CuO(4): a mild "chimie douce" route to superconducting oxyfluoride materials.

PubMed

Delville, M H; Barbut, D; Wattiaux, A; Bassat, J M; Ménétrier, M; Labrugère, C; Grenier, J C; Etourneau, J

2009-08-17

The fluorination of La(2)CuO(4) was achieved for the first time under normal conditions of pressure and temperature (1 MPa and 298 K) via electrochemical insertion in organic fluorinated electrolytes and led to lanthanum oxyfluorides of general formula La(2)CuO(4)F(x). Analyses showed that, underneath a very thin layer of LaF(3) (a few atomic layers), fluorine is effectively inserted in the material's structure. The fluorination strongly modifies the lanthanum environment, whereas very little modification is observed on copper, suggesting an insertion in the La(2)O(2) blocks of the structure. In all cases, fluorine insertion breaks the translation symmetry and introduces a long-distance disorder, as shown by electron spin resonance. These results highlight the efficiency of electrochemistry as a new "chimie douce" type fluorination technique for solid-state materials. Performed at room temperature, it additionally does not require any specific experimental care. The choice of the electrolytic medium is crucial with regard to the fluorine insertion rate as well as the material deterioration. Successful application of this technique to the well-known La(2)CuO(4) material provides a basis for further syntheses from other oxides.

Variable Asymmetric Chains in Transition Metal Oxyfluorides: Structure-Second-Harmonic-Generation Property Relationships.

PubMed

Ahmed, Belal; Jo, Hongil; Oh, Seung-Jin; Ok, Kang Min

2018-05-15

Four novel transition metal oxyfluorides, [Zn(pz) 3 ][MoO 2 F 4 ]·0.1H 2 O (1), [Zn(pz) 2 F 2 ][Zn(pz) 3 ] 2 [WO 2 F 4 ] 2 (2), [Cd(pz) 4 ][Cd(pz) 4 (H 2 O)][MoO 2 F 4 ] 2 ·0.625H 2 O (3), and [Zn(mpz) 3 ] 2 [MoO 2 F 4 ] 2 (4) (pz = pyrazole; mpz = 3-methyl pyrazole) have been synthesized. Compounds 1 and 4 contain helical chains. Compound 2 accommodates zigzag chains, and compound 3 has quasi-one-dimensional linear chains. The variable chain structures are found to be attributable to the different structure-directing anionic groups and hydrogen bonding interactions. Compound 4 crystallized in the noncentrosymmetric (NCS) polar space group, Pna2 1 , is nonphase-matchable (Type I), and reveals a moderate second-harmonic-generation (SHG) efficiency (10 × α-SiO 2 ). The observed SHG efficiency of compound 4 is due to the small net polarization occurring from the arrangement of ZnN 3 F 2 trigonal bipyramids. Spectroscopic and thermal characterizations along with calculations for the title materials are reported.

Investigation of mid-infrared emission characteristics and energy transfer dynamics in Er3+ doped oxyfluoride tellurite glass

PubMed Central

Chen, Fangze; Wei, Tao; Jing, Xufeng; Tian, Ying; Zhang, Junjie; Xu, Shiqing

2015-01-01

Er3+ doped oxyfluoride tellurite glasses have been prepared. Three Judd-Ofelt parameters Ωt (t = 2, 4, 6) and radiative properties are calculated for prepared glasses. Emission characteristics are analyzed and it is found that prepared glasses possess larger calculated predicted spontaneous transition probability (39.97 s−1), emission cross section σem (10.18 × 10−21 cm2) and σem × Δλeff (945.32 × 10−28 cm3), corresponding to the 2.7 μm emission of Er3+: 4I11/2→ 4I13/2 transition. The results suggest that the prepared glasses might be appropriate optical material for mid-infrared laser application. Moreover, rate equation analysis which is rarely used in bulk glass has been carried out to explain the relationship between emission intensity and Er3+ concentration. The calculation results show that with the increment of Er3+ concentration, the energy transfer up-conversion rate of 4I13/2 state increases while the rate of 4I11/2 state reduces, resulting in the change of 2.7 μm emission. PMID:26032900

Inelastic Neutron Scattering Study of the Specific Features of the Phase Transitions in (NH4)2WO2F4

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

Smirnov, Lev S; Kolesnikov, Alexander I; Flerov, I. N.

2009-01-01

Oxyfluoride (NH4)2WO2F4 has been studied by the inelastic neutron scattering method over a wide temperature range 10 300 K at two initial neutron energies of 15 and 60 meV. The role of tetrahedral ammonium groups in the mechanism of sequential phase transitions at T1 = 201 K and T2 = 160 K has been discussed.

Chemistry and Physics of Weakly Ionized Plasmas

DTIC Science & Technology

2010-01-22

temperature: Stabilization of the reactant intermediate A.A. Viggiano, Thomas . M. Miller, Skip Williams, S.T. Arnold, J.V. Seeley , and J.F. Friedman J...16. A Theoretical Study of High Electron Affinity Sulfur Oxyfluorides FSO3, F3SO2, and F5SO Susan T. Arnold, Thomas M. Miller, and A.A. Viggiano...McSweeney, M. D. Hargus, D. M Kerr, Thomas M. Miller, and A. A. Viggiano Int. J. Mass Spectrom. 228, 541-549 (Aug 2003). 37. Reactions and

Transparent Oxyfluoride Nano-Glass-Ceramics Doped with Pr3+ and Pr3+-Yb3+ for NIR Emission

NASA Astrophysics Data System (ADS)

Gorni, Giulio; Cosci, Alessandro; Pelli, Stefano; Pascual, Laura; Durán, Alicia; Pascual, M. J.

2016-12-01

Pr3+-Yb3+ co-doped oxyfluoride glasses and glass-ceramics (GC) containing LaF3 nanocrystals have been prepared to obtain NIR emission of Yb3+ ions upon Pr3+ excitation in the blue region of the visible spectrum. Two different compositions have been tested 0.1-0.5 Pr-Yb and 0.5-1 Pr-Yb, in addition to Pr3+ singly doped samples. The crystallization mechanism of the nano-glass-ceramics was studied by DTA revealing that it occurs from a constant number of nuclei, the crystal growth being limited by diffusion. HR-TEM demonstrated that phase separation acts as precursor for LaF3 crystallization and a detailed analysis of the chemical composition (EDXS) revealed the enrichment in RE3+ ions inside the initial phase separated droplets, from which the LaF3 crystals are formed. The RE3+ ions incorporation inside LaF3 crystals was also proved by photoluminescence measurements showing Stark splitting of the RE3+ ions energy levels in the glass-ceramic samples. Lifetimes measurements showed the existence of a better energy transfer process between Pr3+ and Yb3+ ions in the glass-ceramics compared to the as made glass, and the highest value of energy transfer efficiency is 59% and the highest theoretical quantum efficiency is 159%, obtained for glass-ceramics GC0.1-0.5 Pr-Yb treated at 620 ºC-40 h.

Structural direction of hybrid organic-inorganic materials: Synthesis of vanadium oxyfluoride, copper vanadate, and copper molybdate solid state materials through solvuthermal and solution methods

NASA Astrophysics Data System (ADS)

Deburgomaster, Paul

The vast structural complexity of inorganic oxides with structure directing organocations, nitrogen containing ligands and organophosphonate ligands was explored. The hydrothermal reaction conditions utilized herein include the variables of temperature, pH, fill volume and stoichiometry. The systems studied included: (1) the complex materials rendered from reactions of organoamine cations on the structure of vanadium oxides, oxyfluorides and fluorides. As with other systems, the influence of the mineralizer HF was not limited to pH as fluorine incorporation was not uncommon. In specific cases this coincided with reduction of vanadium sites. (2) The copper-organonitrogen ligand/vanadium oxide/aromatic phosphonate system has been studied. The rigid aromatic di- and tri-phosphonate tethers have provided a series of materials which are structurally distinct from the previously investigated aliphatic series. The inclusion of copper-coordinated nitrogen bi- and tri-dentate ligands also provided structural diversity. Product composition was highly influenced by the HF/V ratio. A similar study was conducted with the ligand 1,4-carboxy-phenylphosphonic acid. (3) The preparation of a series of bimetallic organic-inorganic hybrid materials of the M(II)/VxOy/organonitrogen ligand class was further evidence of the utility of thermodynamically driven hydrothermal synthesis. (4) While decomposition of the spherical Keplerate molybdenum clusters is encountered under hydrothermal conditions, this highly soluble form of molybdate was investigated for the development of hybrid organic-inorganic room temperature solution synthesis.

Spectroscopic and theoretical investigation of the electronic states of layered perovskite oxyfluoride S r2Ru O3F2 thin films

NASA Astrophysics Data System (ADS)

Chikamatsu, Akira; Kurauchi, Yuji; Kawahara, Keisuke; Onozuka, Tomoya; Minohara, Makoto; Kumigashira, Hiroshi; Ikenaga, Eiji; Hasegawa, Tetsuya

2018-06-01

We investigated the electronic structure of a layered perovskite oxyfluoride S r2Ru O3F2 thin film by hard x-ray photoemission spectroscopy (HAXPES) and soft x-ray absorption spectroscopy (XAS) as well as density functional theory (DFT)-based calculations. The core-level HAXPES spectra suggested that S r2Ru O3F2 is a Mott insulator. The DFT calculations described the total and site-projected density of states and the band dispersion for the optimized crystal structure of S r2Ru O3F2 , predicting that R u4 + takes a high-spin configuration of (xy ) ↑(yz ,z x ) ↑↑(3z2-r2 ) ↑ and that S r2Ru O3F2 has an indirect band gap of 0.7 eV with minima at the M ,A and X ,R points. HAXPES spectra near the Fermi level and the angular-dependent O 1 s XAS spectra of the S r2Ru O3F2 thin film, corresponding to the valence band and conduction band density of states, respectively, were drastically different compared to those of the S r2Ru O4 film, suggesting that the changes in the electronic states were mainly driven by the substitution of an oxygen atom coordinated to Ru by fluorine and subsequent modification of the crystal field.

METHOD FOR THE RECOVERY AND PURIFICATION OF GASEOUS UF$sub 6$ FROM GASEOUS MIXTURES AND UF$sub 7$NO AND UF$sub 7$NO$sub 2$ PRODUCTS PRODUCED THEREBY

DOEpatents

Ogle, P.R. Jr.

1962-06-16

A method is given for recovering uranium hexafluoride from a gaseous mixture containing said uranium hexafluoride and extraneous gaseous impurities. The method comprises reacting said mixture with a nitrogen oxyfluoride at a temperature in the range - 100 to 50 deg C to thereby form a solid compound having the empirical formula UF/sub 7/N(O)/sub x/ where x is a number from 1 to 2. (AEC)

Secondary lithium batteries for space applications

NASA Technical Reports Server (NTRS)

Carter, B.; Khanna, S. K.; Yen, S. P. S.; Shen, D.; Somoano, R. B.

1981-01-01

Secondary lithium cells which use a LiAsF6-2-Me-THF electrolyte and a TiS2 intercalatable cathode exhibit encouraging cycle life at ambient temperature. Electrochemical and surface analytical studies indicate that the electrolyte is unstable in the presence of metallic lithium, leading to the formation of a lithium passivating film composed of lithium arsenic oxyfluorides and lithium fluorsilicates. The lithium cyclability remains as the most important problem to solve. Different electrolyte solvents, such as sulfolane, exhibit promising characteristics but lead to new compatibility problems with the other cell component materials.

Laser and gain parameters at 2.7 μm of Er 3+-doped oxyfluoride transparent glass-ceramics

NASA Astrophysics Data System (ADS)

Tikhomirov, V. K.; Méndez-Ramos, J.; Rodríguez, V. D.; Furniss, D.; Seddon, A. B.

2006-07-01

The room temperature emission spectrum at about 2.7 μm corresponding to the laser transition 4I 11/2 → 4I 13/2 in Er 3+-doped nano-scaled transparent oxyfluoride glass-ceramic has been measured and stimulated emission cross-section for the transition has been calculated. The intensity of the transition has been found to be 40 times stronger and lifetime 50 times longer in the glass-ceramics compared to the precursor glass, which we show to be due to a change of frequency of the phonon involved in non-radiative de-excitation of the 4I 11/2 level from 900 cm -1 in the precursor glass to 240 cm -1 in the ensuing glass-ceramics. The absorption cross-section for the excited state absorption 4I 13/2 → 4I 11/2 has been calculated based on the experimental reciprocal emission spectrum and wavelength dependence of the gain cross-section for the lasing transition 4I 11/2 → 4I 13/2 vs population inversion has been derived. The lasing/optical amplification gain parameters, such as population inversion, pump saturation intensity and product of emission cross-section and fluorescence lifetime have been obtained at the 2.7 μm wavelength. A noteworthy result is that laser action at 2.7 μm is possible in these Er 3+-doped glass-ceramics, already not taking into account energy transfer or up-conversion processes, related to the 4I 13/2 level, which favour the population inversion.

A green-yellow emitting oxyfluoride solid solution phosphor Sr[subscript 2]Ba(AlO[subscript 4]F)[subscript 1;#8722;x](SiO[subscript 5])x:Ce[superscript 3+] for thermally stable, high color rendition solid state white lighting

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

Denault, Kristin A.; George, Nathan C.; Paden, Sara R.

2012-10-23

A near-UV excited, oxyfluoride phosphor solid solution Sr{sub 1.975}Ce{sub 0.025}Ba(AlO{sub 4}F){sub 1-x}(SiO{sub 5}){sub x} has been developed for solid state white lighting applications. An examination of the host lattice, and the local structure around the Ce{sup 3+} activator ions through a combination of density functional theory, synchrotron X-ray and neutron powder diffraction and total scattering, and electron paramagnetic resonance, points to how chemical substitutions play a crucial role in tuning the optical properties of the phosphor. The maximum emission wavelength can be tuned from green ({lambda}{sub em} = 523 nm) to yellow ({lambda}{sub em} = 552 nm) by tuning themore » composition, x. Photoluminescent quantum yield is determined to be 70 {+-} 5% for some of the examples in the series. Excellent thermal properties were found for the x = 0.5 sample, with the photoluminescence intensity at 160 C only decreased to 82% of its room temperature value. Phosphor-converted LED devices fabricated using an InGaN LED ({lambda}{sub max} = 400 nm) exhibit high color rendering white light with R{sub a} = 70 and a correlated color temperature near 7000 K. The value of R{sub a} could be raised to 90 by the addition of a red component, and the correlated color temperature lowered to near 4000 K.« less

Cation-substituted spinel oxide and oxyfluoride cathodes for lithium ion batteries

DOEpatents

Manthiram, Arumugam; Choi, Wongchang

2014-05-13

The present invention includes compositions and methods of making cation-substituted and fluorine-substituted spinel cathode compositions by firing a LiMn.sub.2-y-zLi.sub.yM.sub.zO.sub.4 oxide with NH.sub.4HF.sub.2 at low temperatures of between about 300 and 700.degree. C. for 2 to 8 hours and a .eta. of more than 0 and less than about 0.50, mixed two-phase compositions consisting of a spinel cathode and a layered oxide cathode, and coupling them with unmodified or surface modified graphite anodes in lithium ion cells.

Structural and electronic parameters of ferroelectric KWOF

NASA Astrophysics Data System (ADS)

Atuchin, V. V.; Gavrilova, T. A.; Kesler, V. G.; Molokeev, M. S.; Aleksandrov, K. S.

2010-11-01

The low-temperature ferroelectric G2 polymorph of K 3WO 3F 3 oxyfluoride is formed by chemical synthesis. The electronic parameters of G2-K 3WO 3F 3 have been measured by X-ray photoelectron spectroscopy under excitation with Al Kα radiation (1486.6 eV). Detailed spectra have been recorded for all element core levels and Auger lines. The chemical bonding effects in the WO 3F 3 and WO 6 octahedrons are considered by using the binding energy difference ΔBE(O-W)=BE(O 1s)-BE(W 4f).

Measurement of solids motion in gas-fluidized beds. Technical progress report, 1 October 1982-31 December 1982

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

Chen, M.M.; Chao, B.T.

This technical progress report covers the progress made during the fifth quarter of the project entitled Measurements of Solids Motion in Gas Fluidized Beds under Grant No. DOE-F22-81PC40804 during the period 1 October through 31 December 1982. The research concerns the measurement of solids particle velocity distribution and residence time distribution using the Computer-Aided Particle Tracking Facility (CAPTF) at the University of Illinois at Urbana-Champaign. The experimental equipment and measuring methods used to determine particle size distribution and particle motion and the results obtained are presented.

Cation-substituted spinel oxide and oxyfluoride cathodes for lithium ion batteries

DOEpatents

Manthiram, Arumugam; Choi, Wonchang

2010-05-18

The present invention includes compositions and methods of making cation-substituted and fluorine-substituted spinel cathode compositions by firing a LiMn_2-y-zLi_yM_zO₄ oxide with NH₄HF₂ at low temperatures of between about 300 and 700.degree. C. for 2 to 8 hours and a .eta. of more than 0 and less than about 0.50, mixed two-phase compositions consisting of a spinel cathode and a layered oxide cathode, and coupling them with unmodified or surface modified graphite anodes in lithium ion cells.

Graphene sheets stabilized on genetically engineered M13 viral templates as conducting frameworks for hybrid energy-storage materials.

PubMed

Oh, Dahyun; Dang, Xiangnan; Yi, Hyunjung; Allen, Mark A; Xu, Kang; Lee, Yun Jung; Belcher, Angela M

2012-04-10

Utilization of the material-specific peptide-substrate interactions of M13 virus broadens colloidal stability window of graphene. The homogeneous distribution of graphene is maintained in weak acids and increased ionic strengths by complexing with virus. This graphene/virus conducting template is utilized in the synthesis of energy-storage materials to increase the conductivity of the composite electrode. Successful formation of the hybrid biological template is demonstrated by the mineralization of bismuth oxyfluoride as a cathode material for lithium-ion batteries, with increased loading and improved electronic conductivity. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Progress on the three-particle quantization condition

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

Briceno, Raul; Hansen, Mawell T.; Sharpe, Stephen R.

2016-10-01

We report progress on extending the relativistic model-independent quantization condition for three particles, derived previously by two of us, to a broader class of theories, as well as progress on checking the formalism. In particular, we discuss the extension to include the possibility of 2->3 and 3->2 transitions and the calculation of the finite-volume energy shift of an Efimov-like three-particle bound state. The latter agrees with the results obtained previously using non-relativistic quantum mechanics.

Identification of F impurities in F-doped ZnO by synchrotron X-ray absorption near edge structures

NASA Astrophysics Data System (ADS)

Na-Phattalung, Sutassana; Limpijumnong, Sukit; Min, Chul-Hee; Cho, Deok-Yong; Lee, Seung-Ran; Char, Kookrin; Yu, Jaejun

2018-04-01

Synchrotron X-ray absorption near edge structure (XANES) measurements of F K-edge in conjunction with first-principles calculations are used to identify the local structure of the fluorine (F) atom in F-doped ZnO. The ZnO film was grown by pulsed laser deposition with an Nd:YAG laser, and an oxyfluoridation method was used to introduce F ions into the ZnO films. The measured XANES spectrum of the sample was compared against the first-principles XANES calculations based on various models for local atomic structures surrounding F atoms. The observed spectral features are attributed to ZnF2 and FO defects in wurtzite bulk ZnO.

Kinetics of Sulfur Oxide, Sulfur Fluoride, and Sulfur Oxyfluoride Anions with Atomic Species at 298 and 500 K

DTIC Science & Technology

2007-02-01

TABLE 4: Energetics for the HS0 2 - Isomers Calculated Using G2 and G2(MP2) Theory, Including the Vertical Detachment Energy ( VDE ) of the Anion and...548.595 939 76.7 SIOSO- -548.582 037 -548.576 281 151.0 -548.570 411 -548.564 655 155.3 •11298K VDE 298K VDE G2 G2 G2(MP2) G2(MP2) (kJ mol-) (kJ mol-1) (kJ...However, as seen in Table 4, if neutral ( VDE ) values given in Table 4 derived from the neutral energies HS0 2 is produced via vertical electron

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

Sanjeewa, Liurukara D.; McMillen, Colin D.; McGuire, Michael A.

We synthesized manganese vanadate fluorides using high-temperature hydrothermal techniques with BaF 2 as a mineralizer. Ba 3Mn 2(V 2O 7) 2F 2 crystallizes in space group C2/c and consists of dimers built from edge-sharing MnO 4F 2 trigonal prisms with linking V 2O 7 groups. Ba 7Mn 8O 2(VO 4) 2F 23 crystallizes in space group Cmmm, with a manganese oxyfluoride network built from edge- and corner-sharing Mn 2+/3+(O,F) 6 octahedra. The resulting octahedra form alternating Mn 2+ and Mn 2+/3+ layers separated by VO 4 tetrahedra. This latter compound exhibits a canted antiferromagnetic order below TN = 25 K.

Acoustic particle separation

NASA Technical Reports Server (NTRS)

Barmatz, M. B.; Stoneburner, J. D.; Jacobi, N.; Wang, T. (Inventor)

1985-01-01

A method is described which uses acoustic energy to separate particles of different sizes, densities, or the like. The method includes applying acoustic energy resonant to a chamber containing a liquid of gaseous medium to set up a standing wave pattern that includes a force potential well wherein particles within the well are urged towards the center, or position of minimum force potential. A group of particles to be separated is placed in the chamber, while a non-acoustic force such as gravity is applied, so that the particles separate with the larger or denser particles moving away from the center of the well to a position near its edge and progressively smaller lighter particles moving progressively closer to the center of the well. Particles are removed from different positions within the well, so that particles are separated according to the positions they occupy in the well.

U.C. Davis high energy particle physics research: Technical progress report -- 1990

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

NONE

Summaries of progress made for this period is given for each of the following areas: (1) Task A--Experiment, H1 detector at DESY; (2) Task C--Experiment, AMY detector at KEK; (3) Task D--Experiment, fixed target detectors at Fermilab; (4) Task F--Experiment, PEP detector at SLAC and pixel detector; (5) Task B--Theory, particle physics; and (6) Task E--Theory, particle physics.

Phase I: energy conservation potential of Portland Cement particle size distribution control. Progress report, November 1978-January 1979

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

Helmuth, R.A.

1979-03-01

Progress is reported on the energy conservation potential of Portland cement particle size distribution control. Results of preliminary concrete tests, Series IIIa and Series IIIb, effects of particle size ranges on strength and drying shrinkage, are presented. Series IV, effects of mixing and curing temperature, tests compare the properties of several good particle size controlled cements with normally ground cements at low and high temperatures. The work on the effects of high alkali and high sulfate clinker cements (Series V) has begun.

Identify OH groups in TiOF{sub 2} and their impact on the lithium intercalation properties

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

Li, Wei; Body, Monique; Legein, Christophe

A detailed investigation on the chemical composition of the cubic form of titanium oxyfluoride-based compound reveals the presence of OH groups substituting the oxide/ fluoride sublattice. The substitution of oxide by hydroxyl groups induces the presence of titanium vacancies (□) which were characterized by {sup 1}H and {sup 19}F solid-state NMR. {sup 1}H NMR shows that OH groups are present as bridging Ti-OH-Ti or terminal OH groups, i.e. sitting close to a titanium vacancy Ti-OH-□. The electrochemical properties vs. Li{sup +}/Li indicates that the presence of OH groups prevents the intercalation of lithium in the upper voltage region (1.2–3 Vmore » vs. Li{sup +}/Li). Indeed, a partial dehydroxylation of the framework enables to improve the reversibility of the lithium insertion/de-insertion processes. Since the presence of OH groups in this type of compounds is usual and depends on the synthesis method employed, this work enables to rationalize the different electrochemical behaviors reported in the literature and further highlights the importance of a good knowledge of the chemical composition with regard to the physico-chemical properties. - Graphical abstract: The substitution of oxide by hydroxyl groups inducing the formation of titanium vacancies (□), i.e., Ti{sub 1−x}□{sub x}O{sub 1-4x}(OH){sub 4x+y}F{sub 2−y}, was characterized by solid-state {sup 1}H and {sup 19}F NMR. - Highlights: • Evidences of the presence of OH groups and titanium vacancies in titanium oxyfluoride. • {sup 1}H NMR showed the presence of Ti-OH-Ti and Ti-OH-□ species. • The presence of OH groups limits the insertion of lithium within the interstitial sites.« less

Framework influence of erbium doped oxyfluoride glasses on their optical properties

NASA Astrophysics Data System (ADS)

Środa, Marcin; Cholewa-Kowalska, Katarzyna; Różański, Marek; Nocuń, Marek

2011-01-01

Glasses of different matrix (phosphate, borate, silicate and lead-silicate) were studied for their optical properties. The effect of Er dopant on transmittance and luminescence properties was presented. The significant “red shift” and “blue shift” of UV edge absorption were discussed based on the changes in the framework of the borate and phosphate glasses, respectively. It was showed that the integral intensity of the two main optical absorption transitions monotonically increases with the order: phosphate < borate < silicate < lead-silicate. Ellipsometric measurement was applied to obtain the refractive index of the glasses. The correlation between the shift of edge absorption and the change of refractive index was presented. Effect of glassy matrix on luminescence of Er3+ was discussed.

Recent progress of particle migration in viscoelastic fluids.

PubMed

Yuan, Dan; Zhao, Qianbin; Yan, Sheng; Tang, Shi-Yang; Alici, Gursel; Zhang, Jun; Li, Weihua

2018-02-13

Recently, research on particle migration in non-Newtonian viscoelastic fluids has gained considerable attention. In a viscoelastic fluid, three dimensional (3D) particle focusing can be easily realized in simple channels without the need for any external force fields or complex microchannel structures compared with that in a Newtonian fluid. Due to its promising properties for particle precise focusing and manipulation, this field has been developed rapidly, and research on the field has been shifted from fundamentals to applications. This review will elaborate the recent progress of particle migration in viscoelastic fluids, especially on the aspect of applications. The hydrodynamic forces on the micro/nano particles in viscoelastic fluids are discussed. Next, we elaborate the basic particle migration in viscoelasticity-dominant fluids and elasto-inertial fluids in straight channels. After that, a comprehensive review on the applications of viscoelasticity-induced particle migration (particle separation, cell deformability measurement and alignment, particle solution exchange, rheometry-on-a-chip and others) is presented; finally, we thrash out some perspectives on the future directions of particle migration in viscoelastic fluids.

Progressive biogeochemical transformation of placer gold particles drives compositional changes in associated biofilm communities.

PubMed

Rea, Maria Angelica; Standish, Christopher D; Shuster, Jeremiah; Bissett, Andrew; Reith, Frank

2018-05-03

Biofilms on placer gold (Au)-particle surfaces drive Au solubilization and re-concentration thereby progressively transforming the particles. Gold solubilization induces Au-toxicity; however, Au-detoxifying community members ameliorates Au-toxicity by precipitating soluble Au to metallic Au. We hypothesize that Au-dissolution and re-concentration (precipitation) places selective pressures on associated microbial communities, leading to compositional changes and subsequent Au-particle transformation. We analyzed Au-particles from eight United Kingdom sites using next generation sequencing, electron microscopy and micro-analyses. Gold particles contained biofilms composed of prokaryotic cells and extracellular polymeric substances intermixed with (bio)minerals. Across all sites communities were dominated by Proteobacteria (689, 97% Operational Taxonomic Units, 59.3% of total reads), with β-Proteobacteria being the most abundant. A wide range of Au-morphotypes including nanoparticles, micro-crystals, sheet-like Au and secondary rims, indicated that dissolution and re-precipitation occurred, and from this transformation indices were calculated. Multivariate statistical analyses showed a significant relationship between the extent of Au-particle transformation and biofilm community composition, with putative metal-resistant Au-cycling taxa linked to progressive Au transformation. These included the genera Pseudomonas, Leptothrix and Acinetobacter. Additionally, putative exoelectrogenic genera Rhodoferax and Geobacter were highly abundant. In conclusion, biogeochemical Au-cycling and Au-particle transformation occurred at all sites and exerted a strong influence on biofilm community composition.

Recent progress in biopolymer nanoparticle and microparticle formation by heat-treating electrostatic protein-polysaccharide complexes.

PubMed

Jones, Owen G; McClements, David Julian

2011-09-14

Functional biopolymer nanoparticles or microparticles can be formed by heat treatment of globular protein-ionic polysaccharide electrostatic complexes under appropriate solution conditions. These biopolymer particles can be used as encapsulation and delivery systems, fat mimetics, lightening agents, or texture modifiers. This review highlights recent progress in the design and fabrication of biopolymer particles based on heating globular protein-ionic polysaccharide complexes above the thermal denaturation temperature of the proteins. The influence of biopolymer type, protein-polysaccharide ratio, pH, ionic strength, and thermal history on the characteristics of the biopolymer particles formed is reviewed. Our current understanding of the underlying physicochemical mechanisms of particle formation and properties is given. The information provided in this review should facilitate the rational design of biopolymer particles with specific physicochemical and functional attributes, as well as stimulate further research in identifying the physicochemical origin of particle formation. Copyright © 2010 Elsevier B.V. All rights reserved.

Bottom-up substitution assembly of AuF4-n0,-+nPO3 (n = 1-4): a theoretical study of novel oxyfluoride hyperhalogen molecules and anions AuF4-n(PO3)n0,-

NASA Astrophysics Data System (ADS)

Yang, Yi-fan; Cui, Zhong-hua; Ding, Yi-hong

2014-06-01

Compounds with high electron affinity, i.e. superhalogens, have continued to attract chemists' attention, due to their potential importance in fundamental chemistry and materials science. It has now proven very effective to build up novel superhalogens with multi-positively charged centres, which are usually called 'hyperhalogens'. Herein, using AuF4- and PO3 as the model building blocks, we made the first attempt to design the Au,P-based hyperhalogen anions AuF4-n(PO3)n- (n = 1-4) at the B3LYP/6-311+G(d)&SDD and CCSD(T)/6-311+G(d)&SDD (single-point) levels (6-311+G(d) for O, F, P and SDD for Au). Notably, for all the considered Au,P systems, the ground state bears a dioxo-bonded structure with n ≤ 3, which is significantly more stable than the usually presumed mono-oxo-bonded one. Moreover, the clustering of the -PO3 moieties becomes energetically favoured for n ≥ 3. The ground states of AuP4O120,- are the first reported cage-like oxide hyperhalogens. Thus, the -PO3 moiety cannot be retained during the 'bottom-up' assembly. The vertical detachment energy (VDE) value of the most stable AuF4-n(PO3)n- (n = 1-4) ranges from 7.16 to 8.20 eV, higher than the VDE values of the corresponding building blocks AuF4- (7.08 eV) and PO3- (4.69 eV). The adiabatic detachment energy values of these four hyperhalogens exceed 6.00 eV. Possible generation routes for AuF4-n(PO3)n- (n = 1-4) were discussed. The presently designed oxyfluorides not only enriches the family of hyperhalogens, but also demonstrates the great importance of considering the structural transformation during the superhalogen → hyperhalogen design such as for the present Au-P based systems.

* Murine Model of Progressive Orthopedic Wear Particle-Induced Chronic Inflammation and Osteolysis.

PubMed

Pajarinen, Jukka; Nabeshima, Akira; Lin, Tzu-Hua; Sato, Taishi; Gibon, Emmanuel; Jämsen, Eemeli; Lu, Laura; Nathan, Karthik; Yao, Zhenyu; Goodman, Stuart B

2017-12-01

Periprosthetic osteolysis and subsequent aseptic loosening of total joint replacements are driven by byproducts of wear released from the implant. Wear particles cause macrophage-mediated inflammation that culminates with periprosthetic bone loss. Most current animal models of particle-induced osteolysis are based on the acute inflammatory reaction induced by wear debris, which is distinct from the slowly progressive clinical scenario. To address this limitation, we previously developed a murine model of periprosthetic osteolysis that is based on slow continuous delivery of wear particles into the murine distal femur over a period of 4 weeks. The particle delivery was accomplished by using subcutaneously implanted osmotic pumps and tubing, and a hollow titanium rod press-fit into the distal femur. In this study, we report a modification of our prior model in which particle delivery is extended to 8 weeks to better mimic the progressive development of periprosthetic osteolysis and allow the assessment of interventions in a setting where the chronic particle-induced osteolysis is already present at the initiation of the treatment. Compared to 4-week samples, extending the particle delivery to 8 weeks significantly exacerbated the local bone loss observed with μCT and the amount of both peri-implant F4/80 + macrophages and tartrate-resistant acid phosphatase-positive osteoclasts detected with immunohistochemical and histochemical staining. Furthermore, systemic recruitment of reporter macrophages to peri-implant tissues observed with bioluminescence imaging continued even at the later stages of particle-induced inflammation. This modified model system could provide new insights into the mechanisms of chronic inflammatory bone loss and be particularly useful in assessing the efficacy of treatments in a setting that resembles the clinical scenario of developing periprosthetic osteolysis more closely than currently existing model systems.

Basics of particle therapy I: physics

PubMed Central

Park, Seo Hyun

2011-01-01

With the advance of modern radiation therapy technique, radiation dose conformation and dose distribution have improved dramatically. However, the progress does not completely fulfill the goal of cancer treatment such as improved local control or survival. The discordances with the clinical results are from the biophysical nature of photon, which is the main source of radiation therapy in current field, with the lower linear energy transfer to the target. As part of a natural progression, there recently has been a resurgence of interest in particle therapy, specifically using heavy charged particles, because these kinds of radiations serve theoretical advantages in both biological and physical aspects. The Korean government is to set up a heavy charged particle facility in Korea Institute of Radiological & Medical Sciences. This review introduces some of the elementary physics of the various particles for the sake of Korean radiation oncologists' interest. PMID:22984664

Low-temperature synthesis and structural properties of ferroelectric K 3WO 3F 3 elpasolite

NASA Astrophysics Data System (ADS)

Atuchin, V. V.; Gavrilova, T. A.; Kesler, V. G.; Molokeev, M. S.; Aleksandrov, K. S.

2010-06-01

Low-temperature ferroelectric G2 polymorph of K 3WO 3F 3 has been prepared by chemical synthesis. Structural and chemical properties of the final product have been evaluated with X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Structure parameters of G2-K 3WO 3F 3 are refined by the Rietveld method from XRD data measured at room temperature (space group Cm, Z = 2, a = 8.7350(3) Å, b = 8.6808(5) Å, c = 6.1581(3) Å, β = 135.124(3) Å, V = 329.46(3) Å 3; RB = 2.47%). Partial ordering of oxygen and fluorine atoms has been found over anion positions. Mechanism of ferroelectric phase transition in A 2BMO 3F 3 oxyfluorides is discussed.

Energetic particle instabilities in fusion plasmas

NASA Astrophysics Data System (ADS)

Sharapov, S. E.; Alper, B.; Berk, H. L.; Borba, D. N.; Breizman, B. N.; Challis, C. D.; Classen, I. G. J.; Edlund, E. M.; Eriksson, J.; Fasoli, A.; Fredrickson, E. D.; Fu, G. Y.; Garcia-Munoz, M.; Gassner, T.; Ghantous, K.; Goloborodko, V.; Gorelenkov, N. N.; Gryaznevich, M. P.; Hacquin, S.; Heidbrink, W. W.; Hellesen, C.; Kiptily, V. G.; Kramer, G. J.; Lauber, P.; Lilley, M. K.; Lisak, M.; Nabais, F.; Nazikian, R.; Nyqvist, R.; Osakabe, M.; Perez von Thun, C.; Pinches, S. D.; Podesta, M.; Porkolab, M.; Shinohara, K.; Schoepf, K.; Todo, Y.; Toi, K.; Van Zeeland, M. A.; Voitsekhovich, I.; White, R. B.; Yavorskij, V.; TG, ITPA EP; Contributors, JET-EFDA

2013-10-01

Remarkable progress has been made in diagnosing energetic particle instabilities on present-day machines and in establishing a theoretical framework for describing them. This overview describes the much improved diagnostics of Alfvén instabilities and modelling tools developed world-wide, and discusses progress in interpreting the observed phenomena. A multi-machine comparison is presented giving information on the performance of both diagnostics and modelling tools for different plasma conditions outlining expectations for ITER based on our present knowledge.

A Review of Particle Swarm Optimization

NASA Astrophysics Data System (ADS)

Jain, N. K.; Nangia, Uma; Jain, Jyoti

2018-03-01

This paper presents an overview of the research progress in Particle Swarm Optimization (PSO) during 1995-2017. Fifty two papers have been reviewed. They have been categorized into nine categories based on various aspects. This technique has attracted many researchers because of its simplicity which led to many improvements and modifications of the basic PSO. Some researchers carried out the hybridization of PSO with other evolutionary techniques. This paper discusses the progress of PSO, its improvements, modifications and applications.

Intra Articular Therapeutic Delivery for Post Traumatic Osteoarthritis

DTIC Science & Technology

2016-10-01

method. Our central hypotheses are that joint retention time and therapeutic efficacy will be influenced by amniotic membrane particle size ...three Specific Aims: Aim 1: Evaluate the effects of human amniotic membrane (AM) particle size distribution on particle retention and progression of OA...following trauma. Factors we hypothesized would impact therapeutic efficacy of dHACM included particle size , timing of treatment, and frequency of delivery

Thermal and Kinetic Modelling of Elastomer Flow—Application to an Extrusion Die

NASA Astrophysics Data System (ADS)

Launay, J.; Allanic, N.; Mousseau, P.; Deterre, R.

2011-05-01

This paper reports and discusses the thermal and kinetic behaviour of elastomer flow inside an extrusion die. The reaction progress through the runner was modeled by using a particle tracking technique. The aim is to analyze viscous dissipation phenomena to control scorch arisen, improve the rubber compound curing homogeneity and reduce the heating time in the mould using the progress of the induction time. The heat and momentum equations were solved in three dimensions with Ansys Polyflow. A particle tracking technique was set up to calculate the reaction progress. Several simulations were performed to highlight the influence of process parameters and geometry modifications on the rubber compound thermal and cure homogeneity.

Structure and up-conversion luminescence in sol-gel derived Er 3+-Yb 3+ co-doped SiO 2:PbF 2 nano-glass-ceramics

NASA Astrophysics Data System (ADS)

del-Castillo, J.; Yanes, A. C.; Méndez-Ramos, J.; Tikhomirov, V. K.; Rodríguez, V. D.

2009-11-01

Transparent oxyfluoride nano-glass-ceramics 90(SiO 2)10(PbF 2) co-doped with 0.3 Yb 3+ and 0.1 Er 3+ (mol%) have been prepared by thermal treatment of precursor sol-gel glasses. X-ray diffraction and high resolution transmission electron microscopy analysis pointed out a precipitation of cubic β-PbF 2 nanocrystals of certain diameter in nano-glass-ceramics varying from 10 to 20 nm depending on heat treatment conditions. The incorporation of Yb 3+ and Er 3+ dopants in these nanocrystals has been confirmed by signatures of luminescence spectroscopy. Up-conversion luminescence pumped at 980 nm has been detected. Colour tuneability of up-conversion luminescence varying pump power has been analyzed in terms of standard chromaticity diagram. This tuneability opens applications for up-conversion phosphors and three-dimensional optical recording.

Chemical and morphological characteristics of lithium electrode surfaces

NASA Technical Reports Server (NTRS)

Yen, S. P. S.; Shen, D.; Vasquez, R. P.; Grunthaner, F. J.; Somoano, R. B.

1981-01-01

Lithium electrode surfaces were analyzed for chemical and morphological characteristics, using electron spectroscopy chemical analysis (ESCA) and scanning electron microscopy (SEM). Samples included lithium metal and lithium electrodes which were cycled in a 1.5 M lithium arsenic hexafluoride/two-methyl tetrahydrofuran electrolyte. Results show that the surface of the as-received lithium metal was already covered by a film composed of LiO2 and an Li2O/CO2 adduct with a thickness of approximately 100-200 A. No evidence of Ni3 was found. Upon exposure of the lithium electrode to a 1.5 M LiAsF6/2-Me-THF electrochemical environment, a second film was observed to form on the surface, consisting primarily of As, Si, and F, possibly in the form of lithium arsenic oxyfluorides or lithium fluorosilicates. It is suggested that the film formation may be attributed to salt degradation.

Thermal NF3 fluorination/oxidation of cobalt, yttrium, zirconium, and selected lanthanide oxides

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

Scheele, Randall D.; McNamara, Bruce K.; Casella, Andrew M.

2013-02-01

This paper presents results of our continuing investigation on the use of nitrogen trifluoride as a fluorination or fluorination/oxidation agent for separating valuable constituents from used nuclear fuels by exploiting the different volatilities of the constituent fission product and actinide fluorides. This article focuses on fission products that do not have volatile fluorides or oxyfluorides at expected operations temperatures. Our thermodynamic calculations show that nitrogen trifluoride has the potential to completely fluorinate fission product oxides to their fluorides. Simultaneous thermogravimetric and differential thermal analyses show that the oxides of cobalt, zirconium, and the lanthanides are fluorinated but do not formmore » volatile fluorides when treated with nitrogen trifluoride at temperatures up to 550°C. Our studies of gadolinium-doped commercial nuclear fuel indicate that nitrogen trifluoride can extract uranium from the non-volatile gadolinium.« less

Manganese Vanadate Chemistry in Hydrothermal BaF 2 Brines: Ba 3 Mn 2 (V 2 O 7 ) 2 F 2 and Ba 7 Mn 8 O 2 (VO 4 ) 2 F 23

DOE PAGES

Sanjeewa, Liurukara D.; McMillen, Colin D.; McGuire, Michael A.; ...

2016-12-05

We synthesized manganese vanadate fluorides using high-temperature hydrothermal techniques with BaF 2 as a mineralizer. Ba 3Mn 2(V 2O 7) 2F 2 crystallizes in space group C2/c and consists of dimers built from edge-sharing MnO 4F 2 trigonal prisms with linking V 2O 7 groups. Ba 7Mn 8O 2(VO 4) 2F 23 crystallizes in space group Cmmm, with a manganese oxyfluoride network built from edge- and corner-sharing Mn 2+/3+(O,F) 6 octahedra. The resulting octahedra form alternating Mn 2+ and Mn 2+/3+ layers separated by VO 4 tetrahedra. This latter compound exhibits a canted antiferromagnetic order below TN = 25 K.

Refractive Index Dispersion in Ternary Germanate Glasses

NASA Astrophysics Data System (ADS)

Sakaguchi, Shigeki; Todoroki, Shinichi; Rigout, Nathalie

1995-10-01

The refractive index dispersion in germanate oxyfluoride glasses of GeO2-P2O5-MF2 (M=Ca, Zn), which are developed for optical fiber application, is investigated in the 0.4-4 µ m wavelength range by the minimum deviation method. The prepared glasses have a GeO2 content varying from 80 to 30 mol%. The dispersion curves for these glasses tend to shift to shorter wavelengths as the GeO2 content is decreased. Material dispersions are also derived from the refractive index measurements and the zero-material dispersion wavelengths (λ0) are found in the vicinity of 1.5 µ m. On the basis of the empirical relationship between λ0 and the minimum loss wavelength (λ0), the λ min values are located at around 1.8 µ m. A minimum loss of as low as 0.08 dB/km is expected for the present germanate glasses.

Magnetic particle translation as a surrogate measure for synovial fluid mechanics.

PubMed

Shah, Yash Y; Maldonado-Camargo, Lorena; Patel, Neal S; Biedrzycki, Adam H; Yarmola, Elena G; Dobson, Jon; Rinaldi, Carlos; Allen, Kyle D

2017-07-26

The mechanics of synovial fluid vary with disease progression, but are difficult to quantify quickly in a clinical setting due to small sample volumes. In this study, a novel technique to measure synovial fluid mechanics using magnetic nanoparticles is introduced. Briefly, microspheres embedded with superparamagnetic iron oxide nanoparticles, termed magnetic particles, are distributed through a 100μL synovial fluid sample. Then, a permanent magnet inside a protective sheath is inserted into the synovial fluid sample. Magnetic particles translate toward the permanent magnet and the percentage of magnetic particles collected by the magnet in a given time can be related to synovial fluid viscosity. To validate this relationship, magnetic particle translation was demonstrated in three phases. First, magnetic particle translation was assessed in glycerol solutions with known viscosities, demonstrating that as fluid viscosity increased, magnetic particle translation decreased. Next, the relationship between magnetic particle translation and synovial fluid viscosity was assessed using bovine synovial fluid that was progressively degenerated via ultrasonication. Here, particle collection in a given amount of time increased as fluid degenerated, demonstrating that the relationship between particle collection and fluid mechanics holds in non-Newtonian synovial fluid. Finally, magnetic particle translation was used to assess differences between healthy and OA affected joints in equine synovial fluid. Here, particle collection in a given time was higher in OA joints relative to healthy horses (p<0.001). Combined, these data demonstrate potential viability of magnetic particle translation in a clinical setting to evaluate synovial fluid mechanics in limited volumes of synovial fluid sample. Copyright © 2017 Elsevier Ltd. All rights reserved.

MISR UAE2 Aerosol Versioning

Atmospheric Science Data Center

2013-03-21

... The "Beta" designation means particle microphysical property validation is in progress, uncertainty envelopes on particle size distribution, ... UAE-2 campaign activities are part of the validation process, so two versions of the MISR aerosol products are included in this ...

General Relativistic Smoothed Particle Hydrodynamics code developments: A progress report

NASA Astrophysics Data System (ADS)

Faber, Joshua; Silberman, Zachary; Rizzo, Monica

2017-01-01

We report on our progress in developing a new general relativistic Smoothed Particle Hydrodynamics (SPH) code, which will be appropriate for studying the properties of accretion disks around black holes as well as compact object binary mergers and their ejecta. We will discuss in turn the relativistic formalisms being used to handle the evolution, our techniques for dealing with conservative and primitive variables, as well as those used to ensure proper conservation of various physical quantities. Code tests and performance metrics will be discussed, as will the prospects for including smoothed particle hydrodynamics codes within other numerical relativity codebases, particularly the publicly available Einstein Toolkit. We acknowledge support from NSF award ACI-1550436 and an internal RIT D-RIG grant.

A 3-D model of tumor progression based on complex automata driven by particle dynamics.

PubMed

Wcisło, Rafał; Dzwinel, Witold; Yuen, David A; Dudek, Arkadiusz Z

2009-12-01

The dynamics of a growing tumor involving mechanical remodeling of healthy tissue and vasculature is neglected in most of the existing tumor models. This is due to the lack of efficient computational framework allowing for simulation of mechanical interactions. Meanwhile, just these interactions trigger critical changes in tumor growth dynamics and are responsible for its volumetric and directional progression. We describe here a novel 3-D model of tumor growth, which combines particle dynamics with cellular automata concept. The particles represent both tissue cells and fragments of the vascular network. They interact with their closest neighbors via semi-harmonic central forces simulating mechanical resistance of the cell walls. The particle dynamics is governed by both the Newtonian laws of motion and the cellular automata rules. These rules can represent cell life-cycle and other biological interactions involving smaller spatio-temporal scales. We show that our complex automata, particle based model can reproduce realistic 3-D dynamics of the entire system consisting of the tumor, normal tissue cells, blood vessels and blood flow. It can explain phenomena such as the inward cell motion in avascular tumor, stabilization of tumor growth by the external pressure, tumor vascularization due to the process of angiogenesis, trapping of healthy cells by invading tumor, and influence of external (boundary) conditions on the direction of tumor progression. We conclude that the particle model can serve as a general framework for designing advanced multiscale models of tumor dynamics and it is very competitive to the modeling approaches presented before.

Evaluation of caries progression in dentin treated by fluoride-containing materials using an in-air micro-PIGE and micro-PIXE measurement system

NASA Astrophysics Data System (ADS)

Yamamoto, H.; Iwami, Y.; Yagi, K.; Hayashi, M.; Komatsu, H.; Okuyama, K.; Matsuda, Y.; Yasuda, K.

2015-04-01

It is well-known that fluorine (F) is involved in the progression of caries. The evaluation of caries progression has conventionally been based on the change in mineral content using transverse microradiography (TMR). The purpose of this study was to evaluate the progression of dentinal caries by the change in calcium (Ca) content using Particle-Induced Gamma-ray Emission/Particle-Induced X-ray Emission (PIGE/PIXE) techniques at the Wakasa Wan Energy Research Center. We also assessed the relationship between caries progression rate and the concentration of F penetration into dentin from dental fluoride-containing materials (FCMs). Dentin sections of six extracted human teeth were prepared to obtain various amounts of F uptake using three types of FCMs. F and Ca distribution of specimens were obtained using PIGE/PIXE techniques. After evaluation, the specimens were immersed in 10 ml of demineralizing solution (pH 4.5) to simulate caries attack. To estimate caries progression rates, the same portions of the specimens were evaluated after caries attack treatment using PIGE/PIXE. A negative correlation between the F uptake in dentin and the rate of caries progression was observed. Therefore, caries progression in dentin was reduced by increasing the amount of F uptake from FCMs. This demonstrates that PIGE/PIXE techniques are valuable for estimating caries progression rates.

Respiratory dose assessment of inhaled particles: continuing progress

EPA Science Inventory

Internal dose is a key factor for determining the health risk ofinhaled pollutant particles on the one hand and the efficacy ofdrug inhalantsonthe other. Accurateestimation ofrespiratorydose, however, is a difficult task because multiple factors come to play roles in the process....

Some Progress in Large-Eddy Simulation using the 3-D Vortex Particle Method

NASA Technical Reports Server (NTRS)

Winckelmans, G. S.

1995-01-01

This two-month visit at CTR was devoted to investigating possibilities in LES modeling in the context of the 3-D vortex particle method (=vortex element method, VEM) for unbounded flows. A dedicated code was developed for that purpose. Although O(N(sup 2)) and thus slow, it offers the advantage that it can easily be modified to try out many ideas on problems involving up to N approx. 10(exp 4) particles. Energy spectrums (which require O(N(sup 2)) operations per wavenumber) are also computed. Progress was realized in the following areas: particle redistribution schemes, relaxation schemes to maintain the solenoidal condition on the particle vorticity field, simple LES models and their VEM extension, possible new avenues in LES. Model problems that involve strong interaction between vortex tubes were computed, together with diagnostics: total vorticity, linear and angular impulse, energy and energy spectrum, enstrophy. More work is needed, however, especially regarding relaxation schemes and further validation and development of LES models for VEM. Finally, what works well will eventually have to be incorporated into the fast parallel tree code.

Progress in Titanium Metal Powder Injection Molding.

PubMed

German, Randall M

2013-08-20

Metal powder injection molding is a shaping technology that has achieved solid scientific underpinnings. It is from this science base that recent progress has occurred in titanium powder injection molding. Much of the progress awaited development of the required particles with specific characteristics of particle size, particle shape, and purity. The production of titanium components by injection molding is stabilized by a good understanding of how each process variable impacts density and impurity level. As summarized here, recent research has isolated the four critical success factors in titanium metal powder injection molding (Ti-MIM) that must be simultaneously satisfied-density, purity, alloying, and microstructure. The critical role of density and impurities, and the inability to remove impurities with sintering, compels attention to starting Ti-MIM with high quality alloy powders. This article addresses the four critical success factors to rationalize Ti-MIM processing conditions to the requirements for demanding applications in aerospace and medical fields. Based on extensive research, a baseline process is identified and reported here with attention to linking mechanical properties to the four critical success factors.

Progress in Titanium Metal Powder Injection Molding

PubMed Central

German, Randall M.

2013-01-01

Metal powder injection molding is a shaping technology that has achieved solid scientific underpinnings. It is from this science base that recent progress has occurred in titanium powder injection molding. Much of the progress awaited development of the required particles with specific characteristics of particle size, particle shape, and purity. The production of titanium components by injection molding is stabilized by a good understanding of how each process variable impacts density and impurity level. As summarized here, recent research has isolated the four critical success factors in titanium metal powder injection molding (Ti-MIM) that must be simultaneously satisfied—density, purity, alloying, and microstructure. The critical role of density and impurities, and the inability to remove impurities with sintering, compels attention to starting Ti-MIM with high quality alloy powders. This article addresses the four critical success factors to rationalize Ti-MIM processing conditions to the requirements for demanding applications in aerospace and medical fields. Based on extensive research, a baseline process is identified and reported here with attention to linking mechanical properties to the four critical success factors. PMID:28811458

ENGINEERING NANO- AND MICRO-PARTICLES TO TUNE IMMUNITY

PubMed Central

Moon, James J.; Irvine, Darrell J.; Huang, Bonnie

2013-01-01

The immune system can be a cure or cause of disease, fulfilling a protective role in attacking cancer or pathogenic microbes but also causing tissue destruction in autoimmune disorders. Thus, therapies aimed to amplify or suppress immune reactions are of great interest. However, the complex regulation of the immune system, coupled with the potential systemic side effects associated with traditional systemic drug therapies, has presented a major hurdle for the development of successful immunotherapies,. Recent progress in the design of synthetic micro- and nano-particles that can target drugs, deliver imaging agents, or stimulate immune cells directly through their physical and chemical properties is leading to new approaches to deliver vaccines, promote immune responses against tumors, and suppress autoimmunity. In addition, novel strategies, such as the use of particle-laden immune cells as living targeting agents for drugs, are providing exciting new approaches for immunotherapy. This progress report describes recent advances in the design of micro- and nano-particles in immunotherapies and diagnostics. PMID:22641380

DIESEL EXHAUST PARTICLES INDUCE ABERRANT ALVEOLAR EPITHELIAL DIRECTED CELL MOVEMENT BY DISRUPTION OF POLARITY MECHANISMS

EPA Science Inventory

Disruption of the respiratory epithelium contributes to the progression of a variety of respiratory diseases that are aggravated by exposure to air pollutants, specifically traffic-based pollutants such as diesel exhaust particles (DEP). Recognizing that lung repair following inj...

Technologies for delivery of proton and ion beams for radiotherapy

NASA Astrophysics Data System (ADS)

Owen, Hywel; Holder, David; Alonso, Jose; Mackay, Ranald

2014-05-01

Recent developments for the delivery of proton and ion beam therapy have been significant, and a number of technological solutions now exist for the creation and utilisation of these particles for the treatment of cancer. In this paper we review the historical development of particle accelerators used for external beam radiotherapy and discuss the more recent progress towards more capable and cost-effective sources of particles.

The effect of air dust pollution on semen quality and sperm parameters among infertile men in west of Iran.

PubMed

Najafpour, Ali; Aghaz, Faranak; Roshankhah, Shiva; Bakhtiari, Mitra

2018-06-26

Pollutants during haze and Asian dust storms are transported out of the Asian continent, affecting the regional climate and the hydrological and biogeochemical cycles. Nonetheless, no specific studies evaluated the dust particles influence on semen quality in a specific geographical area. In this article, we investigated the effect of dust particles on semen quality and sperm parameters among infertile men. A descriptive-analytic study was conducted among 850 infertile men between 2011 and 2015 years. Semen quality was assessed according to the WHO 2010 guidelines, including sperm concentration, progressive motility, and morphology. Four-year average dust particle concentrations were estimated at each participant's address using the Air Pollution Monitoring Station affiliated with the Department of Environment of Kermanshah city were gathered. Dust particle levels were highest in the summer months, in Kermanshah province. Our results show that, dust pollution was found to be significantly negatively correlated with sperm morphology and sperm concentration before and after lab-processing, but sperm progressive motility is low sensitive to dust particles. Our findings showed that exposures to dust particle may influence sperm quantity in infertile men, consistent with the knowledge that sperm morphology and concentration are the most sensitive parameters of dust pollution.

THE SMALL VOLUME PARTICLE MICROSAMPLER (SVPM): A NEW APPROACH TO PARTICLE SIZE DISTRIBUTION AND COMPOSITION. (R827090)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

LUNG INFLAMMATION INDUCED BY CONCENTRATED AMBIENT AIR PARTICLES IS RELATED TO PARTICLE COMPOSITION. (R827353C008)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

New Quantum Diffusion Monte Carlo Method for strong field time dependent problems

NASA Astrophysics Data System (ADS)

Kalinski, Matt

2017-04-01

We have recently formulated the Quantum Diffusion Quantum Monte Carlo (QDMC) method for the solution of the time-dependent Schrödinger equation when it is equivalent to the reaction-diffusion system coupled by the highly nonlinear potentials of the type of Shay. Here we formulate a new Time Dependent QDMC method free of the nonlinearities described by the constant stochastic process of the coupled diffusion with transmutation. As before two kinds of diffusing particles (color walkers) are considered but which can further also transmute one into the other. Each of the species undergoes the hypothetical Einstein random walk progression with transmutation. The progressed particles transmute into the particles of the other kind before contributing to or annihilating the other particles density. This fully emulates the Time Dependent Schrödinger equation for any number of quantum particles. The negative sign of the real and the imaginary parts of the wave function is handled by the ``spinor'' densities carrying the sign as the degree of freedom. We apply the method for the exact time-dependent observation of our discovered two-electron Langmuir configurations in the magnetic and circularly polarized fields.

Background and Recent Progress in Anomalous Transport Simulation

DTIC Science & Technology

2017-07-19

NUMBER (Include area code) 19 July 2017 Briefing Charts 14 June 2017 - 19 July 2017 Background and Recent Progress in Anomalous Transport Simulation ...and Recent Progress in Anomalous Transport Simulation 19 Jul 2017 Justin Koo AFRL/RQRS Edwards AFB, CA 2DISTRIBUTION A: Approved for public release...Baalrud, S.D. and Chabert, P., “Theory for the anomalous electron transport in Hall effect thrusters. I. Insights from particle-in-cell simulations

On thermalization of electron-positron-photon plasma

NASA Astrophysics Data System (ADS)

Siutsou, I. A.; Aksenov, A. G.; Vereshchagin, G. V.

2015-12-01

Recently a progress has been made in understanding thermalization mechanism of relativistic plasma starting from a non-equilibrium state. Relativistic Boltzmann equations were solved numerically for homogeneous isotropic plasma with collision integrals for two- and three-particle interactions calculated from the first principles by means of QED matrix elements. All particles were assumed to fulfill Boltzmann statistics. In this work we follow plasma thermalization by accounting for Bose enhancement and Pauli blocking in particle interactions. Our results show that particle in equilibrium reach Bose-Einstein distribution for photons, and Fermi-Dirac one for electrons, respectively.

Particle acceleration, transport and turbulence in cosmic and heliospheric physics

NASA Technical Reports Server (NTRS)

Matthaeus, W.

1992-01-01

In this progress report, the long term goals, recent scientific progress, and organizational activities are described. The scientific focus of this annual report is in three areas: first, the physics of particle acceleration and transport, including heliospheric modulation and transport, shock acceleration and galactic propagation and reacceleration of cosmic rays; second, the development of theories of the interaction of turbulence and large scale plasma and magnetic field structures, as in winds and shocks; third, the elucidation of the nature of magnetohydrodynamic turbulence processes and the role such turbulence processes might play in heliospheric, galactic, cosmic ray physics, and other space physics applications.

Rare-earth doped transparent nano-glass-ceramics: a new generation of photonic integrated devices

NASA Astrophysics Data System (ADS)

Rodríguez-Armas, Vicente Daniel; Tikhomirov, Victor K.; Méndez-Ramos, Jorge; Yanes, Angel C.; Del-Castillo, Javier; Furniss, David; Seddon, Angela B.

2007-05-01

We report on optical properties and prospect applications on rare-earth doped oxyfluoride precursor glass and ensuing nano-glass-ceramics. We find out the spectral optical gain of the nano-glass-ceramics and show that its flatness and breadth are advantageous as compared to contemporary used erbium doped optical amplifiers. We present the possibility of flat gain cross-section erbium doped waveguide amplifiers as short 'chip', all-optical, devices capable of dense wavelength division multiplexing, including the potential for direct writing of these devices inside bulk glasses for three-dimensional photonic integration. We carried out a comparative study of the up-conversion luminescence in Er 3+-doped and Yb 3+-Er 3+-Tm 3+ co-doped samples, which indicates that these materials can be used as green/red tuneable up-conversion phosphors and white light simulation respectively. Observed changes in the spectra of the up-conversion luminescence provide a tool for tuning the colour opening the way for producing 3-dimensional optical recording.

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

Liang, Kun; Marcus, Kyle; Yang, Zhenzhong

In this work, a freestanding NiFe oxyfluoride (NiFeOF) holey film was prepared by electrochemical deposition and anodic treatments. With the combination of good electrical conductivity and holey structure, the NiFeOF holey film offers superior electrochemical performance, due to the following reasons: (i) The residual metal alloy framework can be used as the current collector to improve electrode conductivity. Moreover, the as-prepared freestanding NiFeOF holey film can be used as a supercapacitor electrode without reliance on binders and other additives. The residual metal alloy framework and binder-free electrode effectively reduces electrode resistance, thus improving electron transport. (ii) The highly interconnected holeymore » structure and hierarchical pore distribution provides a high specific surface area to improve electron transport, enhancing rapid ion transport and mitigating diffusion limitations throughout the holey film. (iii) The excellent mechanical characteristics facilitate flexibility and cyclability related performance. Additionally, the NiFeOF holey film presents exceptional electrochemical performance, showing that it is a promising alternative for small/micro-size electronic devices.« less

Comprehensive insights into the structural and chemical changes in mixed-anion FeOF electrodes by using operando PDF and NMR spectroscopy.

PubMed

Wiaderek, Kamila M; Borkiewicz, Olaf J; Castillo-Martínez, Elizabeth; Robert, Rosa; Pereira, Nathalie; Amatucci, Glenn G; Grey, Clare P; Chupas, Peter J; Chapman, Karena W

2013-03-13

In-depth analysis of operando X-ray pair distribution function (PDF) data is combined with Li NMR spectroscopy to gain comprehensive insights into the electrochemical reaction mechanism of high-performance iron oxyfluoride electrodes. While the full discharge capacity could be recovered upon charge, implying reversibility of the electrochemical reaction, the atomic structure of the electrode formed after cycling (discharge-charge) differs from the pristine uncycled electrode material. Instead, the "active" electrode that forms upon cycling is a nanocomposite of an amorphous rutile phase and a nanoscale rock salt phase. Bond valence sum analysis, based on the precise structural parameters (bond lengths and coordination number) extracted from the in situ PDF data, suggests that anion partitioning occurs during the electrochemical reaction, with the rutile phase being F-rich and the rock salt phase being O-rich. The F- and O-rich phases react sequentially; Fe in a F-rich environment reacts preferentially during both discharge and charge.

Overall Water Splitting with Room-Temperature Synthesized NiFe Oxyfluoride Nanoporous Films

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

Liang, Kun; Guo, Limin; Marcus, Kyle

Freestanding and lightweight thin-films were rationally designed to serve as robust electrodes for renewable energy applications. A facile and scalable nanomanufacturing process was developed to fabricate these transformative thin-film electrodes (iron group mixed oxides) that exhibit a nanoporous structure and controllable composition. More specifically, electrodeposition and anodic treatments were employed to produce freestanding and lightweight metal oxides nanoporous layers (NPL). These NPL can be directly used as flexible and additive-free electrodes for renewable energy generation (water splitting) and storage (supercapacitor) applications without requiring binders and current collector and other additives. Significantly enhanced electrochemical performance was achieved due to the uniquemore » merits of the NPL: i) highly porous structure considerably increases the electrode/electrolyte interface, which facilitate electrochemical reactions; ii) NPL substantially increase the number of active sites that are favorable in electrochemical reactions; iii) residual metal network within the NPL forms a conductive framework, drastically improving electrode strength, flexibility and conductivity.« less

Fluorescence properties of Eu3+ ions doped borate and fluoroborate glasses containing lithium, zinc and lead.

PubMed

Venkatramu, V; Babu, P; Jayasankar, C K

2006-02-01

The influence of glass composition on the fluorescence properties of Eu3+ ions doped borate and fluoroborate glasses modified with Li+, Zn2+ and Pb2+ cations have been investigated. The magnitude of splittings of 7F1 levels are analyzed using crystal-field (CF) analysis. The relative intensities of 5D0 --> 7F2 to 5D0 --> 7F1 transitions, crystal-field strength parameters and decay times of the 5D0 level have been determined and are found to be lower for Pb based glasses than those of Zn/Li based glasses. The lifetimes of 5D0 level are found to increase when borate glasses are modified with pure fluorides than with oxides and oxyfluorides. The fluorescence decay of 5D0 level fits perfect single exponential in the Eu3+:glass systems studied which indicates the absence of energy transfer between Eu3+ ions in these glasses.

Research in cosmic and gamma ray astrophysics: Cosmic physics portion

NASA Technical Reports Server (NTRS)

Stone, Edward C.; Mewaldt, Richard A.; Schindler, Stephen

1993-01-01

Research in particle astrophysics at the Space Radiation Laboratory (SRL) of the California Institute of Technology is supported under NASA Grant NAGW-1919. A three-year proposal for continuation of support was submitted a year ago and put into effect 1 October 1992. This report is the combined progress report and continuation application called for under the Federal Demonstration Project. Gamma-ray Astrophysics at SRL is separately supported under NAGW-1919 and will be separately summarized and proposed. This report will document progress and plans for our particle spectroscopy activities and for related data analysis, calibration, and community service activities. A bibliography and a budget will be attached as appendices. The Caltech SRL research program includes a heavy emphasis on elemental and isotopic spectroscopy of energetic particles in the cosmic radiation; in solar, interplanetary, and anomalous 'cosmic' radiation; and in planetary magnetospheres as discussed.

Burning rate for steel-cased, pressed binderless HMX

NASA Technical Reports Server (NTRS)

Fifer, R. A.; Cole, J. E.

1980-01-01

The burning behavior of pressed binderless HMX laterally confined in 6.4 mm i.d. steel cases was measured over the pressure range 1.45 to 338 MPa in a constant pressure strand burner. The measured regression rates are compared to those reported previously for unconfined samples. It is shown that lateral confinement results in a several-fold decrease in the regression rate for the coarse particle size HMX above the transition to super fast regression. For class E samples, confinement shifts the transition to super fast regression from low pressure to high pressure. These results are interpreted in terms of the previously proposed progressive deconsolidation mechanism. Preliminary holographic photography and closed bomb tests are also described. Theoretical one dimensional modeling calculations were carried out to predict the expected flame height (particle burn out distance) as a function of particle size and pressure for binderless HMX burning by a progressive deconsolidation mechanism.

Progress in our understanding of cometary dust tails

NASA Technical Reports Server (NTRS)

Sekanina, Z.

1976-01-01

Various analytical techniques are employed to analyze observations on the character, composition, and size distribution of solid particles in cometary dust tails. Emphasized is the mechanical theory that includes solar gravitational attraction and solar radiation pressure to explain dust particle motions in cometary tails, as well as interactions between dust and plasma.

DISPERSION POLYMERIZATIONS OF METHYL METHACRYLATE IN SUPERCRITICAL CARBON DIOXIDE: THE INFLUENCE OF HELIUM CONCENTRATION ON PARTICLE SIZE AND PARTICLE SIZE DISTRIBUTION. (R826115)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

DOES THE HARVARD/U.S. ENVIRONMENTAL PROTECTION AGENCY AMBIENT PARTICLE CONCENTRATOR CHANGE THE TOXIC POTENTIAL OF PARTICLES? (R827353C008)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Acoustic attraction, repulsion and radiation force cancellation on a pair of rigid particles with arbitrary cross-sections in 2D: Circular cylinders example

NASA Astrophysics Data System (ADS)

Mitri, F. G.

2017-11-01

The acoustic radiation forces arising on a pair of sound impenetrable cylindrical particles of arbitrary cross-sections are derived. Plane progressive, standing or quasi-standing waves with an arbitrary incidence angle are considered. Multiple scattering effects are described using the multipole expansion formalism and the addition theorem of cylindrical wave functions. An effective incident acoustic field on a particular object is determined, and used with the scattered field to derive closed-form analytical expressions for the radiation force vector components. The mathematical expressions for the radiation force components are exact, and have been formulated in partial-wave series expansions in cylindrical coordinates involving the angle of incidence, the reflection coefficient forming the progressive or the (quasi)standing wave field, the addition theorem, and the expansion coefficients. Numerical examples illustrate the analysis for two rigid circular cross-sections immersed in a non-viscous fluid. Computations for the dimensionless radiation force functions are performed with emphasis on varying the angle of incidence, the interparticle distance, the sizes of the particles as well as the characteristics of the incident field. Depending on the interparticle distance and angle of incidence, one of the particles yields neutrality; it experiences no force and becomes unresponsive (i.e., ;invisible;) to the linear momentum transfer of the effective incident field due to multiple scattering cancellation effects. Moreover, attractive or repulsive forces between the two particles may arise depending on the interparticle distance, the angle of incidence and size parameters of the particles. This study provides a complete analytical method and computations for the axial and transverse radiation force components in multiple acoustic scattering encompassing the cases of plane progressive, standing or quasi-standing waves of arbitrary incidence by a pair of scatterers. Potential applications concern the prediction of the forces used in acoustically-engineered metamaterials with reconfigurable periodicities, cloaking devices, and liquid crystals to name a few examples.

Progress in the Analysis of Complex Atmospheric Particles.

PubMed

Laskin, Alexander; Gilles, Mary K; Knopf, Daniel A; Wang, Bingbing; China, Swarup

2016-06-12

This article presents an overview of recent advances in field and laboratory studies of atmospheric particles formed in processes of environmental air-surface interactions. The overarching goal of these studies is to advance predictive understanding of atmospheric particle composition, particle chemistry during aging, and their environmental impacts. The diversity between chemical constituents and lateral heterogeneity within individual particles adds to the chemical complexity of particles and their surfaces. Once emitted, particles undergo transformation via atmospheric aging processes that further modify their complex composition. We highlight a range of modern analytical approaches that enable multimodal chemical characterization of particles with both molecular and lateral specificity. When combined, these approaches provide a comprehensive arsenal of tools for understanding the nature of particles at air-surface interactions and their reactivity and transformations with atmospheric aging. We discuss applications of these novel approaches in recent studies and highlight additional research areas to explore the environmental effects of air-surface interactions.

Experimental Study of Short-Time Brownian Motion

NASA Astrophysics Data System (ADS)

Mo, Jianyong; Simha, Akarsh; Riegler, David; Raizen, Mark

2015-03-01

We report our progress on the study of short-time Brownian motion of optically-trapped microspheres. In earlier work, we observed the instantaneous velocity of microspheres in gas and in liquid, verifying a prediction by Albert Einstein from 1907. We now report a more accurate test of the energy equipartition theorem for a particle in liquid. We also observe boundary effects on Brownian motion in liquid by setting a wall near the trapped particle, which changes the dynamics of the motion. We find that the velocity autocorrelation of the particle decreases faster as the particle gets closer to the wall.

Talking about German Verb Particles Identified in Concordance Lines--From Spontaneous to Expert-Like Metatalk

ERIC Educational Resources Information Center

Schaeffer-Lacroix, Eva

2016-01-01

Johns reports in his text "Kibbitzing one-to-ones" (1997) that corpus-informed metatalk with a foreign language expert helps apprentice writers to make progress in independent text revision. Expecting this progress to be based on the development of expert-like ways to observe language features, I integrated Johns' so-called kibbitzing…

Single Aerosol Particle Studies Using Optical Trapping Raman And Cavity Ringdown Spectroscopy

NASA Astrophysics Data System (ADS)

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

2017-12-01

Due to the physical and chemical complexity of aerosol particles and the interdisciplinary nature of aerosol science that involves physics, chemistry, and biology, our knowledge of aerosol particles is rather incomplete; our current understanding of aerosol particles is limited by averaged (over size, composition, shape, and orientation) and/or ensemble (over time, size, and multi-particles) measurements. Physically, single aerosol particles are the fundamental units of any large aerosol ensembles. Chemically, single aerosol particles carry individual chemical components (properties and constituents) in particle ensemble processes. Therefore, the study of single aerosol particles can bridge the gap between aerosol ensembles and bulk/surface properties and provide a hierarchical progression from a simple benchmark single-component system to a mixed-phase multicomponent system. A single aerosol particle can be an effective reactor to study heterogeneous surface chemistry in multiple phases. Latest technological advances provide exciting new opportunities to study single aerosol particles and to further develop single aerosol particle instrumentation. We present updates on our recent studies of single aerosol particles optically trapped in air using the optical-trapping Raman and cavity ringdown spectroscopy.

The joint NASA/Goddard-University of Maryland research program in charged particle and high energy photon detector technology

NASA Technical Reports Server (NTRS)

1986-01-01

Progress made in the following areas is discussed: low energy ion and electron experiments; instrument design for current experiments; magnetospheric measurement of particles; ion measurement in the earth plasma sheet; abundance measurement; X-ray data acquisition; high energy physics; extragalactic astronomy; compact object astrophysics; planetology; and high energy photon detector technology.

Progress in the Analysis of Complex Atmospheric Particles

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

Laskin, Alexander; Gilles, Mary K.; Knopf, Daniel A.

2016-06-16

This manuscript presents an overview on recent advances in field and laboratory studies of atmospheric particles formed in processes of environmental air-surfaces interactions. The overarching goal of these studies is to advance predictive understanding of atmospheric particle composition, particle chemistry during aging, and their environmental impacts. The diversity between chemical constituents and lateral heterogeneity within individual particles adds to the chemical complexity of particles and their surfaces. Once emitted, particles undergo transformation via atmospheric aging processes that further modify their complex composition. We highlight a range of modern analytical approaches that enable multi-modal chemical characterization of particles with both molecularmore » and lateral specificity. When combined, they provide a comprehensive arsenal of tools for understanding the nature of particles at air-surface interactions and their reactivity and transformations with atmospheric aging. We discuss applications of these novel approaches in recent studies and highlight additional research areas to explore environmental effects of air-surface interactions.« less

Progress in the analysis of complex atmospheric particles

DOE PAGES

Laskin, Alexander; Gilles, Mary K.; Knopf, Daniel A.; ...

2016-06-01

This study presents an overview of recent advances in field and laboratory studies of atmospheric particles formed in processes of environmental air-surface interactions. The overarching goal of these studies is to advance predictive understanding of atmospheric particle composition, particle chemistry during aging, and their environmental impacts. The diversity between chemical constituents and lateral heterogeneity within individual particles adds to the chemical complexity of particles and their surfaces. Once emitted, particles undergo transformation via atmospheric aging processes that further modify their complex composition. We highlight a range of modern analytical approaches that enable multimodal chemical characterization of particles with both molecularmore » and lateral specificity. When combined, these approaches provide a comprehensive arsenal of tools for understanding the nature of particles at air-surface interactions and their reactivity and transformations with atmospheric aging. We discuss applications of these novel approaches in recent studies and highlight additional research areas to explore the environmental effects of air-surface interactions.« less

Laboratory Directed Research and Development FY 1998 Progress Report

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

John Vigil; Kyle Wheeler

This is the FY 1998 Progress Report for the Laboratory Directed Research and Development (LDRD) Program at Los Alamos National Laboratory. It gives an overview of the LDRD Program, summarizes work done on individual research projects, relates the projects to major Laboratory program sponsors, and provides an index to the principle investigators. Project summaries are grouped by their LDRD component: Competency Development, Program Development, and Individual Projects. Within each component, they are further grouped into nine technical categories: (1) materials science, (2) chemistry, (3) mathematics and computational science, (4) atomic, molecular, optical, and plasma physics, fluids, and particle beams, (5)more » engineering science, (6) instrumentation and diagnostics, (7) geoscience, space science, and astrophysics, (8) nuclear and particle physics, and (9) bioscience.« less

Laboratory directed research and development: FY 1997 progress report

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

Vigil, J.; Prono, J.

1998-05-01

This is the FY 1997 Progress Report for the Laboratory Directed Research and Development (LDRD) program at Los Alamos National Laboratory. It gives an overview of the LDRD program, summarizes work done on individual research projects, relates the projects to major Laboratory program sponsors, and provides an index to the principal investigators. Project summaries are grouped by their LDRD component: Competency Development, Program Development, and Individual Projects. Within each component, they are further grouped into nine technical categories: (1) materials science, (2) chemistry, (3) mathematics and computational science, (4) atomic and molecular physics and plasmas, fluids, and particle beams, (5)more » engineering science, (6) instrumentation and diagnostics, (7) geoscience, space science, and astrophysics, (8) nuclear and particle physics, and (9) bioscience.« less

Research in the Theory of Condensed Matter and Elementary Particles: Final Report, September 1, 1984 - November 30, 1987

DOE R&D Accomplishments Database

Friedan, D.; Kadanoff, L.; Nambu, Y.; Shenker, S.

1988-04-01

Progress is reported in the field of condensed matter physics in the area of two-dimensional critical phenomena, specifically results allowing complete classification of all possible two-dimensional critical phenomena in a certain domain. In the field of high energy physics, progress is reported in string and conformal field theory, and supersymmetry.

Spontaneous deswelling of pNIPAM microgels at high concentrations

NASA Astrophysics Data System (ADS)

Gasser, Urs; Scotti, Andrea; Herman, Emily S.; Pelaez-Fernandez, Miguel; Han, Jun; Menzel, Andreas; Lyon, L. Andrew; Fernandez-Nieves, Alberto

Polydisperse suspensions of pNIPAM microgel particles show a unique, spontaneous particle deswelling behavior. Beyond a critical concentration, the largest microgels deswell and thereby reduce the polydispersity of the suspension. We have recently unraveled the mechanism of this spontaneous, selective deswelling. pNIPAM microgels carry charged sulfate groups originating from the ammonium persulfate starter used in particle synthesis. Most of the ammonium counterions are trapped close to the microgel surface, but a fraction of them escapes the electrostatic attraction and contributes to the osmotic pressure of the suspension. The counterion clouds of neighboring particles progressively overlap with increasing volume fraction, leading to an increase of free counterions and the osmotic pressure outside but not inside the microgel particles. We find particles to deswell when the resulting osmotic pressure difference between the inside and the outside becomes larger their bulk modulus. For pNIPAM microgels synthesized with the same protocol, the largest particles are the softest and deswell first.

Progress Toward a Multidimensional Representation of Mortar Interior Ballistics

DTIC Science & Technology

2009-06-01

reached, act as rigid bodies within the chamber. Using computational particles to represent the propellant charge permits a host of modeling features...walls are represented by special Lagrange particles, which remain impermeable (hence the charges act as rigid bodies ) until a specified wall...composition, and table 2 provides the thermochemical calculations done using Cheetah (14), the basis of which is discussed in Schmidt and Nusca (12

Laboratory directed research and development. FY 1995 progress report

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

Vigil, J.; Prono, J.

1996-03-01

This document presents an overview of Laboratory Directed Research and Development Programs at Los Alamos. The nine technical disciplines in which research is described include materials, engineering and base technologies, plasma, fluids, and particle beams, chemistry, mathematics and computational science, atmic and molecular physics, geoscience, space science, and astrophysics, nuclear and particle physics, and biosciences. Brief descriptions are provided in the above programs.

Loss in lung volume and changes in the immune response demonstrate disease progression in African green monkeys infected by small-particle aerosol and intratracheal exposure to Nipah virus.

PubMed

Cong, Yu; Lentz, Margaret R; Lara, Abigail; Alexander, Isis; Bartos, Christopher; Bohannon, J Kyle; Hammoud, Dima; Huzella, Louis; Jahrling, Peter B; Janosko, Krisztina; Jett, Catherine; Kollins, Erin; Lackemeyer, Matthew; Mollura, Daniel; Ragland, Dan; Rojas, Oscar; Solomon, Jeffrey; Xu, Ziyue; Munster, Vincent; Holbrook, Michael R

2017-04-01

Nipah virus (NiV) is a paramyxovirus (genus Henipavirus) that emerged in the late 1990s in Malaysia and has since been identified as the cause of sporadic outbreaks of severe febrile disease in Bangladesh and India. NiV infection is frequently associated with severe respiratory or neurological disease in infected humans with transmission to humans through inhalation, contact or consumption of NiV contaminated foods. In the work presented here, the development of disease was investigated in the African Green Monkey (AGM) model following intratracheal (IT) and, for the first time, small-particle aerosol administration of NiV. This study utilized computed tomography (CT) and magnetic resonance imaging (MRI) to temporally assess disease progression. The host immune response and changes in immune cell populations over the course of disease were also evaluated. This study found that IT and small-particle administration of NiV caused similar disease progression, but that IT inoculation induced significant congestion in the lungs while disease following small-particle aerosol inoculation was largely confined to the lower respiratory tract. Quantitative assessment of changes in lung volume found up to a 45% loss in IT inoculated animals. None of the subjects in this study developed overt neurological disease, a finding that was supported by MRI analysis. The development of neutralizing antibodies was not apparent over the 8-10 day course of disease, but changes in cytokine response in all animals and activated CD8+ T cell numbers suggest the onset of cell-mediated immunity. These studies demonstrate that IT and small-particle aerosol infection with NiV in the AGM model leads to a severe respiratory disease devoid of neurological indications. This work also suggests that extending the disease course or minimizing the impact of the respiratory component is critical to developing a model that has a neurological component and more accurately reflects the human condition.

Loss in lung volume and changes in the immune response demonstrate disease progression in African green monkeys infected by small-particle aerosol and intratracheal exposure to Nipah virus

PubMed Central

Cong, Yu; Lentz, Margaret R.; Lara, Abigail; Alexander, Isis; Bartos, Christopher; Bohannon, J. Kyle; Hammoud, Dima; Huzella, Louis; Jahrling, Peter B.; Janosko, Krisztina; Jett, Catherine; Kollins, Erin; Lackemeyer, Matthew; Mollura, Daniel; Ragland, Dan; Rojas, Oscar; Solomon, Jeffrey; Xu, Ziyue; Munster, Vincent

2017-01-01

Nipah virus (NiV) is a paramyxovirus (genus Henipavirus) that emerged in the late 1990s in Malaysia and has since been identified as the cause of sporadic outbreaks of severe febrile disease in Bangladesh and India. NiV infection is frequently associated with severe respiratory or neurological disease in infected humans with transmission to humans through inhalation, contact or consumption of NiV contaminated foods. In the work presented here, the development of disease was investigated in the African Green Monkey (AGM) model following intratracheal (IT) and, for the first time, small-particle aerosol administration of NiV. This study utilized computed tomography (CT) and magnetic resonance imaging (MRI) to temporally assess disease progression. The host immune response and changes in immune cell populations over the course of disease were also evaluated. This study found that IT and small-particle administration of NiV caused similar disease progression, but that IT inoculation induced significant congestion in the lungs while disease following small-particle aerosol inoculation was largely confined to the lower respiratory tract. Quantitative assessment of changes in lung volume found up to a 45% loss in IT inoculated animals. None of the subjects in this study developed overt neurological disease, a finding that was supported by MRI analysis. The development of neutralizing antibodies was not apparent over the 8–10 day course of disease, but changes in cytokine response in all animals and activated CD8+ T cell numbers suggest the onset of cell-mediated immunity. These studies demonstrate that IT and small-particle aerosol infection with NiV in the AGM model leads to a severe respiratory disease devoid of neurological indications. This work also suggests that extending the disease course or minimizing the impact of the respiratory component is critical to developing a model that has a neurological component and more accurately reflects the human condition. PMID:28388650

Supercritical fluid particle design for poorly water-soluble drugs (review).

PubMed

Sun, Yongda

2014-01-01

Supercritical fluid particle design (SCF PD) offers a number of routes to improve solubility and dissolution rate for enhancing the bioavailability of poorly water-soluble drugs, which can be adopted through an in-depth knowledge of SCF PD processes and the molecular properties of active pharmaceutical ingredients (API) and drug delivery system (DDS). Combining with research experiences in our laboratory, this review focuses on the most recent development of different routes (nano-micron particles, polymorphic particles, composite particles and bio-drug particles) to improve solubility and dissolution rate of poorly water-soluble drugs, covering the fundamental concept of SCF and the principle of SCF PD processes which are typically used to control particle size, shape, morphology and particle form and hence enable notable improvement in the dissolution rate of the poorly water-soluble drugs. The progress of the industrialization of SCF PD processes in pharmaceutical manufacturing environment with scaled-up plant under current good manufacturing process (GMP) specification is also considered in this review.

Functionalised particles using dry powder coating in pharmaceutical drug delivery: promises and challenges.

PubMed

Dahmash, Eman Z; Mohammed, Afzal R

2015-01-01

Production of functionalised particles using dry powder coating is a one-step, environmentally friendly process that paves the way for the development of particles with targeted properties and diverse functionalities. Applying the first principles in physical science for powders, fine guest particles can be homogeneously dispersed over the surface of larger host particles to develop functionalised particles. Multiple functionalities can be modified including: flowability, dispersibility, fluidisation, homogeneity, content uniformity and dissolution profile. The current publication seeks to understand the fundamental underpinning principles and science governing dry coating process, evaluate key technologies developed to produce functionalised particles along with outlining their advantages, limitations and applications and discusses in detail the resultant functionalities and their applications. Dry particle coating is a promising solvent-free manufacturing technology to produce particles with targeted functionalities. Progress within this area requires the development of continuous processing devices that can overcome challenges encountered with current technologies such as heat generation and particle attrition. Growth within this field requires extensive research to further understand the impact of process design and material properties on resultant functionalities.

Modern views on the composition of anionic oxy-fluoride complexes of aluminium and their rearrangement during the electrolysis of cryolite-alumina melts

NASA Astrophysics Data System (ADS)

Khramov, A. P.; Shurov, N. I.

2014-08-01

Some consequences of the hypothesis of the absence of free F- ions in cryolite-alumina melts are observed. The melt at 1 < CR < 3 is assumed to consist of the complexes AlF{6/3-}, AlF{5/2-}, AlF{4/-}, Al2OF{6/2-}, and Al2O2F{4/2-}, and alkali metal cations. A formal-stoichiometric study of the processes occurring during electrolysis is performed on the basis of the accepted hypothesis. Judgments about some of the features of the electrode reactions and chemical reactions in the electrolyte volume are presented. The reaction schemes for the instances with and without the subsequent/preceding chemical reaction near the electrode or in the molten salt volume are given. The mass flows of various forms of ionic complexes through the electrolyte volume are given for these schemes. Definitive conclusions are not made in the study, but the range of possible variants for the electrochemical routes of the overall chemical reaction in the cell is limited.

Formation of anodic layers on InAs (111)III. Study of the chemical composition

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

Valisheva, N. A., E-mail: valisheva@thermo.isp.nsc.ru; Tereshchenko, O. E.; Prosvirin, I. P.

2012-04-15

The chemical composition of {approx}20-nm-thick anodic layers grown on InAs (111)III in alkaline and acid electrolytes containing or not containing NH{sub 4}F is studied by X-ray photoelectron spectroscopy. It is shown that the composition of fluorinated layers is controlled by the relation between the concentrations of fluorine and hydroxide ions in the electrolyte and by diffusion processes in the growing layer. Fluorine accumulates at the (anodic layer)/InAs interface. Oxidation of InAs in an acid electrolyte with a low oxygen content and a high NH{sub 4}F content brings about the formation of anodic layers with a high content of fluorine andmore » elemental arsenic and the formation of an oxygen-free InF{sub x}/InAs interface. Fluorinated layers grown in an alkaline electrolyte with a high content of O{sup 2-} and/or OH{sup -} groups contain approximately three times less fluorine and consist of indium and arsenic oxyfluorides. No distinction between the compositions of the layers grown in both types of fluorine-free electrolytes is established.« less

Photocatalytic Active Bismuth Fluoride/Oxyfluoride Surface Crystallized 2Bi2O3-B2O3 Glass-Ceramics

NASA Astrophysics Data System (ADS)

Sharma, Sumeet Kumar; Singh, V. P.; Chauhan, Vishal S.; Kushwaha, H. S.; Vaish, Rahul

2018-03-01

The present article deals with 2Bi2O3-B2O3 (BBO) glass whose photocatalytic activity has been enhanced by the method of wet etching using an aqueous solution of hydrofluoric acid (HF). X-ray diffraction of the samples reveals that etching with an aqueous solution of HF leads to the formation of BiF3 and BiO0.1F2.8 phases. Surface morphology obtained from scanning electron microscopy show granular and plate-like morphology on the etched glass samples. Rhodamine 6G (Rh 6G) has been used to investigate the photocatalytic activity of the as-quenched and etched glasses. Enhanced visible light-driven photocatalytic activity was observed in HF etched glass-ceramics compared to the as-quenched BBO glass. Contact angle of the as-quenched glass was 90.2°, which decreases up to 20.02° with an increase in concentration of HF in the etching solution. Enhanced photocatalytic activity and increase in the hydrophilic nature suggests the efficient treatment of water pollutants by using the prepared surface crystallized glass-ceramics.

Microscale simulations of shock interaction with large assembly of particles for developing point-particle models

NASA Astrophysics Data System (ADS)

Thakur, Siddharth; Neal, Chris; Mehta, Yash; Sridharan, Prasanth; Jackson, Thomas; Balachandar, S.

2017-01-01

Micrsoscale simulations are being conducted for developing point-particle and other related models that are needed for the mesoscale and macroscale simulations of explosive dispersal of particles. These particle models are required to compute (a) instantaneous aerodynamic force on the particle and (b) instantaneous net heat transfer between the particle and the surrounding. A strategy for a sequence of microscale simulations has been devised that allows systematic development of the hybrid surrogate models that are applicable at conditions representative of the explosive dispersal application. The ongoing microscale simulations seek to examine particle force dependence on: (a) Mach number, (b) Reynolds number, and (c) volume fraction (different particle arrangements such as cubic, face-centered cubic (FCC), body-centered cubic (BCC) and random). Future plans include investigation of sequences of fully-resolved microscale simulations consisting of an array of particles subjected to more realistic time-dependent flows that progressively better approximate the actual problem of explosive dispersal. Additionally, effects of particle shape, size, and number in simulation as well as the transient particle deformation dependence on various parameters including: (a) particle material, (b) medium material, (c) multiple particles, (d) incoming shock pressure and speed, (e) medium to particle impedance ratio, (f) particle shape and orientation to shock, etc. are being investigated.

Visibility and Haze

EPA Pesticide Factsheets

Haze forms when sunlight encounters particle pollution. It reduces visibility in cities and scenic areas. This web area provides regulatory information and progress towards improving visibility through EPA’s regional haze program.

Final Progress Report for Ionospheric Dusty Plasma In the Laboratory [Smokey Plasma

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

Robertson, Scott

2010-07-31

“Ionospheric Dusty Plasma in the Laboratory” is a research project with the purpose of finding and reproducing the characteristics of plasma in the polar mesosphere that is unusually cold (down to 140 K) and contains nanometer-sized dust particles. This final progress report summarizes results from four years of effort that include a final year with a no-cost extension.

Report of NRL Progress. Fifty Years of Science for the Navy and the Nation, 1923-1973

DTIC Science & Technology

1973-07-01

on High Energy Physics in September, 1960. In the decade of the sixties we were gradually to disengage from elementary particle physicsf in ...Progress, July 1973 IQI M. M. SHAPIRO Figure 2 - A high - energy interaction of a nitrogen nucleus in photographic emul- sion. The nitrogen ion from ...particularly as induced by a radiation environment. In the

Laboratory laser acceleration and high energy astrophysics: {gamma}-ray bursts and cosmic rays

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

Tajima, T.; Takahashi, Y.

1998-08-20

Recent experimental progress in laser acceleration of charged particles (electrons) and its associated processes has shown that intense electromagnetic pulses can promptly accelerate charged particles to high energies and that their energy spectrum is quite hard. On the other hand some of the high energy astrophysical phenomena such as extremely high energy cosmic rays and energetic components of {gamma}-ray bursts cry for new physical mechanisms for promptly accelerating particles to high energies. The authors suggest that the basic physics involved in laser acceleration experiments sheds light on some of the underlying mechanisms and their energy spectral characteristics of the promptlymore » accelerated particles in these high energy astrophysical phenomena.« less

Particulate matter induced enhancement of inflammatory markers in the brains of apolipoprotein E knockout mice.

PubMed

Campbell, Arezoo; Araujo, Jesus A; Li, Huihui; Sioutas, Constantinos; Kleinman, Michael

2009-08-01

Exposure to air particulate matter (PM) present in urban environments have been shown to induce systemic prooxidant and proinflammatory effects in apolipoprotein E knockout (ApoE-/-) mice and proinflammatory central nervous system (CNS) effects in BALB/c mice. We hypothesize that ApoE-/- mice would exhibit a greater propensity to develop PM-induced CNS effects due to their greater susceptibility to CNS inflammation. We studied the brains of ApoE-/- mice exposed in a previous study to concentrated air particles of different sizes (fine vs. ultrafine) or filtered-air to evaluate the effect of PM exposure on the development of CNS proinflammatory effects in a genetically susceptible background. This was important because, although the use of nano-sized materials opens an exciting potential for their use as diagnostic or therapeutic tools, not much is known about the possible CNS toxicity of these particles. Neuroinflammation has been shown to exacerbate progression of neurodegeneration. Since the onset and progression of idiopathic forms of neurodegenerative disorders are likely to be multifactorial and involve gene-environment interactions, we determined the possibility of particles in ambient air pollution to enhance neuroinflammation. Our results indicate that in the brain, there was significant modulation in the activation of the transcription factors NF-kappaB and AP-1 after exposure to the ultrafine fractions. Levels of two pro-inflammatory cytokines (TNF-alpha and IL-1alpha) were also increased in the brain of exposed animals and this was independent of the size fraction of PM. Since inflammatory processes have been shown to contribute to the pathology associated with neurodegenerative diseases, it will be important to further evaluate the role ambient particles may play in the potentiation of existing CNS damage and progression of neurodegenerative disorders.

Advanced computations in plasma physics

NASA Astrophysics Data System (ADS)

Tang, W. M.

2002-05-01

Scientific simulation in tandem with theory and experiment is an essential tool for understanding complex plasma behavior. In this paper we review recent progress and future directions for advanced simulations in magnetically confined plasmas with illustrative examples chosen from magnetic confinement research areas such as microturbulence, magnetohydrodynamics, magnetic reconnection, and others. Significant recent progress has been made in both particle and fluid simulations of fine-scale turbulence and large-scale dynamics, giving increasingly good agreement between experimental observations and computational modeling. This was made possible by innovative advances in analytic and computational methods for developing reduced descriptions of physics phenomena spanning widely disparate temporal and spatial scales together with access to powerful new computational resources. In particular, the fusion energy science community has made excellent progress in developing advanced codes for which computer run-time and problem size scale well with the number of processors on massively parallel machines (MPP's). A good example is the effective usage of the full power of multi-teraflop (multi-trillion floating point computations per second) MPP's to produce three-dimensional, general geometry, nonlinear particle simulations which have accelerated progress in understanding the nature of turbulence self-regulation by zonal flows. It should be emphasized that these calculations, which typically utilized billions of particles for thousands of time-steps, would not have been possible without access to powerful present generation MPP computers and the associated diagnostic and visualization capabilities. In general, results from advanced simulations provide great encouragement for being able to include increasingly realistic dynamics to enable deeper physics insights into plasmas in both natural and laboratory environments. The associated scientific excitement should serve to stimulate improved cross-cutting collaborations with other fields and also to help attract bright young talent to plasma science.

Advanced Computation in Plasma Physics

NASA Astrophysics Data System (ADS)

Tang, William

2001-10-01

Scientific simulation in tandem with theory and experiment is an essential tool for understanding complex plasma behavior. This talk will review recent progress and future directions for advanced simulations in magnetically-confined plasmas with illustrative examples chosen from areas such as microturbulence, magnetohydrodynamics, magnetic reconnection, and others. Significant recent progress has been made in both particle and fluid simulations of fine-scale turbulence and large-scale dynamics, giving increasingly good agreement between experimental observations and computational modeling. This was made possible by innovative advances in analytic and computational methods for developing reduced descriptions of physics phenomena spanning widely disparate temporal and spatial scales together with access to powerful new computational resources. In particular, the fusion energy science community has made excellent progress in developing advanced codes for which computer run-time and problem size scale well with the number of processors on massively parallel machines (MPP's). A good example is the effective usage of the full power of multi-teraflop MPP's to produce 3-dimensional, general geometry, nonlinear particle simulations which have accelerated progress in understanding the nature of turbulence self-regulation by zonal flows. It should be emphasized that these calculations, which typically utilized billions of particles for tens of thousands time-steps, would not have been possible without access to powerful present generation MPP computers and the associated diagnostic and visualization capabilities. In general, results from advanced simulations provide great encouragement for being able to include increasingly realistic dynamics to enable deeper physics insights into plasmas in both natural and laboratory environments. The associated scientific excitement should serve to stimulate improved cross-cutting collaborations with other fields and also to help attract bright young talent to plasma science.

Workshop on the Analysis of Interplanetary Dust Particles

NASA Technical Reports Server (NTRS)

Zolensky, Michael E. (Editor)

1994-01-01

Great progress has been made in the analysis of interplanetary dust particles (IDP's) over the past few years. This workshop provided a forum for the discussion of the following topics: observation and modeling of dust in the solar system, mineralogy and petrography of IDP's, processing of IDP's in the solar system and terrestrial atmosphere, comparison of IDP's to meteorites and micrometeorites, composition of IDP's, classification, and collection of IDP's.

Current status of direct dark matter detection experiments

NASA Astrophysics Data System (ADS)

Liu, Jianglai; Chen, Xun; Ji, Xiangdong

2017-03-01

Much like ordinary matter, dark matter might consist of elementary particles, and weakly interacting massive particles are one of the prime suspects. During the past decade, the sensitivity of experiments trying to directly detect them has improved by three to four orders of magnitude, but solid evidence for their existence is yet to come. We overview the recent progress in direct dark matter detection experiments and discuss future directions.

Effects of damage and thermal residual stresses on the overall elastoplastic behavior of particle-reinforced metal matrix composites

NASA Astrophysics Data System (ADS)

Liu, Haitao

The objective of the present study is to investigate damage mechanisms and thermal residual stresses of composites, and to establish the frameworks to model the particle-reinforced metal matrix composites with particle-matrix interfacial debonding, particle cracking or thermal residual stresses. An evolutionary interfacial debonding model is proposed for the composites with spheroidal particles. The construction of the equivalent stiffness is based on the fact that when debonding occurs in a certain direction, the load-transfer ability will lose in that direction. By using this equivalent method, the interfacial debonding problem can be converted into a composite problem with perfectly bonded inclusions. Considering the interfacial debonding is a progressive process in which the debonding area increases in proportion to external loading, a progressive interfacial debonding model is proposed. In this model, the relation between external loading and the debonding area is established using a normal stress controlled debonding criterion. Furthermore, an equivalent orthotropic stiffness tensor is constructed based on the debonding areas. This model is able to study the composites with randomly distributed spherical particles. The double-inclusion theory is recalled to model the particle cracking problems. Cracks inside particles are treated as penny-shape particles with zero stiffness. The disturbed stress field due to the existence of a double-inclusion is expressed explicitly. Finally, a thermal mismatch eigenstrain is introduced to simulate the inconsistent expansions of the matrix and the particles due to the difference of the coefficients of thermal expansion. Micromechanical stress and strain fields are calculated due to the combination of applied external loads and the prescribed thermal mismatch eigenstrains. For all of the above models, ensemble-volume averaging procedures are employed to derive the effective yield function of the composites. Numerical simulations are performed to analyze the effects of various parameters and several good agreements between our model's predictions and experimental results are obtained. It should be mentioned that all of expressions in the frameworks are explicitly derived and these analytical results are easy to be adopted in other related investigations.

Levitated Optomechanics for Fundamental Physics

NASA Astrophysics Data System (ADS)

Rashid, Muddassar; Bateman, James; Vovrosh, Jamie; Hempston, David; Ulbricht, Hendrik

2015-05-01

Optomechanics with levitated nano- and microparticles is believed to form a platform for testing fundamental principles of quantum physics, as well as find applications in sensing. We will report on a new scheme to trap nanoparticles, which is based on a parabolic mirror with a numerical aperture of 1. Combined with achromatic focussing, the setup is a cheap and readily straightforward solution to trapping nanoparticles for further study. Here, we report on the latest progress made in experimentation with levitated nanoparticles; these include the trapping of 100 nm nanodiamonds (with NV-centres) down to 1 mbar as well as the trapping of 50 nm Silica spheres down to 10?4 mbar without any form of feedback cooling. We will also report on the progress to implement feedback stabilisation of the centre of mass motion of the trapped particle using digital electronics. Finally, we argue that such a stabilised particle trap can be the particle source for a nanoparticle matterwave interferometer. We will present our Talbot interferometer scheme, which holds promise to test the quantum superposition principle in the new mass range of 106 amu. EPSRC, John Templeton Foundation.

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.

A novel sheet-like virus particle array is a hallmark of Zika virus infection.

PubMed

Liu, Jun; Kline, Brandon A; Kenny, Tara A; Smith, Darci R; Soloveva, Veronica; Beitzel, Brett; Pang, Song; Lockett, Stephen; Hess, Harald F; Palacios, Gustavo; Kuhn, Jens H; Sun, Mei G; Zeng, Xiankun

2018-04-25

Zika virus (ZIKV) is an emerging flavivirus that caused thousands of human infections in recent years. Compared to other human flaviviruses, ZIKV replication is not well understood. Using fluorescent, transmission electron, and focused ion beam-scanning electron microscopy, we examined ZIKV replication dynamics in Vero 76 cells and in the brains of infected laboratory mice. We observed the progressive development of a perinuclear flaviviral replication factory both in vitro and in vivo. In vitro, we illustrated the ZIKV lifecycle from particle cell entry to egress. ZIKV particles assembled and aggregated in an induced convoluted membrane structure and ZIKV strain-specific membranous vesicles. While most mature virus particles egressed via membrane budding, some particles also likely trafficked through late endosomes and egressed through membrane abscission. Interestingly, we consistently observed a novel sheet-like virus particle array consisting of a single layer of ZIKV particles. Our study further defines ZIKV replication and identifies a novel hallmark of ZIKV infection.

Removal of the commercial pesticides Novadim Progress, Bordeaux mixture and Karate Zeon by pullulan derivatives based flocculants.

PubMed

Ghimici, Luminita; Constantin, Marieta

2018-04-14

Cationic pullulan derivatives have been synthesized and evaluated, for the first time, as flocculants for the separation of the commercial pesticides, Novadim Progress (organophosphoric type), Bordeax mixture and Karate Zeon (pyrethroid type) from synthetic wastewater. The investigated polymer samples contained either pendent tertiary amine or quaternary ammonium salts groups. The separation efficiency was followed by UV-Vis spectroscopy, while the information regarding the mechanism involved in the separation of pesticide particles have been obtained by zeta potential. UV-Vis spectroscopy data showed strong pesticide particles/polycation interactions in case of Novadim Progress and Bordeaux mixture (maximum pesticide removal between 90% and 98%). Good separation efficiency (around 80%) of Karate Zeon emulsion was also noticed. The zeta potential measurements indicated that the charge neutralization was the common flocculation mechanism for the removal of these pesticides. In addition, the hydrogen bondings and chelation of copper ions by amide and/or tertiary amino groups of the polycations had a noteworthy contribution to the pesticide removal. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cloud condensation nuclei droplet growth kinetics of ultrafine particles during anthropogenic nucleation events

NASA Astrophysics Data System (ADS)

Shantz, N. C.; Pierce, J. R.; Chang, R. Y.-W.; Vlasenko, A.; Riipinen, I.; Sjostedt, S.; Slowik, J. G.; Wiebe, A.; Liggio, J.; Abbatt, J. P. D.; Leaitch, W. R.

2012-02-01

Evolution of the cloud condensation nucleus (CCN) activity of 36 ± 4 nm diameter anthropogenic aerosol particles at a water supersaturation of 1.0 ± 0.1% is examined for particle nucleation and growth. During the early stages of one event, relatively few of the anthropogenic particles at 36 nm were CCN active and their growth rates by water condensation were delayed relative to ammonium sulphate particles. As the event progressed, the particle size distribution evolved to larger sizes and the relative numbers of particles at 36 nm that were CCN active increased until all the 36 nm particles were activating at the end of the event. Based on the chemistry of larger particles and the results from an aerosol chemical microphysics box model, the increase in CCN activity of the particles was most likely the result of the condensation of sulphate in this case. Despite the increased CCN activity, a delay was observed in the initial growth of these particles into cloud droplets, which persisted even when the aerosol was most CCN active later in the afternoon. Simulations show that the delay in water uptake is explained by a reduction of the mass accommodation coefficient assuming that the composition of the 36 nm particles is the same as the measured composition of the 60-100 nm particles.

Estimation of Particle Flux and Remineralization Rate from Radioactive Disequilibrium

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

Michael P. Bacon; Roger Francois

2004-05-24

Reactive radionuclides, such as the thorium isotopes, show measurable deficiencies in the oceanic water column because of their removal by chemical scavenging due to the particle flux. Measurement of the deficiency, coupled with measurement of the radionuclide concentration in particles, allows a determination of the effective particle sinking velocity. Results to date suggest that the effective particle sinking velocity is remarkably invariant with depth. This leads to the tentative suggestion that POC concentration profiles may, to a good approximation, be used directly to determine length scales for the remineralization of sinking organic matter. Further measurements are in progress to testmore » this idea and to evaluate its limitations. Knowledge of the remineralization length scale is essential to an evaluation of the efficiency of the biological pump as a means for deep sequestering of carbon in the ocean.« less

Progress in the synthesis and characterization of magnetite nanoparticles with amino groups on the surface

NASA Astrophysics Data System (ADS)

Durdureanu-Angheluta, A.; Dascalu, A.; Fifere, A.; Coroaba, A.; Pricop, L.; Chiriac, H.; Tura, V.; Pinteala, M.; Simionescu, B. C.

2012-05-01

This manuscript deals with the synthesis of new hydrophilic magnetite particles by employing a two-step method: in the first step magnetite particles with hydrophobic shell formed in presence of oleic acid-oleylamine complex through a synthesis in mass, without solvent, in a mortar with pestle were obtained; while in the second step the hydrophobic shell was interchanged with an aminosilane monomer. The influence of the Fe2+/Fe3+ molar ratio on the dimension of the particles of high importance for their potential applications was carefully investigated. This paper, also presents an alternative method of synthesis of new core-shell magnetite particles and the complete study of their structure and morphology by FT-IR, XPS, TGA, ESEM and TEM techniques. The rheological properties and magnetization analysis of high importance for magnetic particles were also investigated.

CRYSTAL GROWTH. Crystallization by particle attachment in synthetic, biogenic, and geologic environments.

PubMed

De Yoreo, James J; Gilbert, Pupa U P A; Sommerdijk, Nico A J M; Penn, R Lee; Whitelam, Stephen; Joester, Derk; Zhang, Hengzhong; Rimer, Jeffrey D; Navrotsky, Alexandra; Banfield, Jillian F; Wallace, Adam F; Michel, F Marc; Meldrum, Fiona C; Cölfen, Helmut; Dove, Patricia M

2015-07-31

Field and laboratory observations show that crystals commonly form by the addition and attachment of particles that range from multi-ion complexes to fully formed nanoparticles. The particles involved in these nonclassical pathways to crystallization are diverse, in contrast to classical models that consider only the addition of monomeric chemical species. We review progress toward understanding crystal growth by particle-attachment processes and show that multiple pathways result from the interplay of free-energy landscapes and reaction dynamics. Much remains unknown about the fundamental aspects, particularly the relationships between solution structure, interfacial forces, and particle motion. Developing a predictive description that connects molecular details to ensemble behavior will require revisiting long-standing interpretations of crystal formation in synthetic systems, biominerals, and patterns of mineralization in natural environments. Copyright © 2015, American Association for the Advancement of Science.

Elastic collisions of classical point particles on a finite frictionless linear track with perfectly reflecting endpoints

NASA Astrophysics Data System (ADS)

DeLuca, R.

2006-03-01

Repeated elastic collisions of point particles on a finite frictionless linear track with perfectly reflecting endpoints are considered. The problem is analysed by means of an elementary linear algebra approach. It is found that, starting with a state consisting of a projectile particle in motion at constant velocity and a target particle at rest in a fixed known position, the points at which collisions occur on track, when plotted versus progressive numerals, corresponding to the collisions themselves, show periodic patterns for a rather large choice of values of the initial position x(0) and on the mass ratio r. For certain values of these parameters, however, only regular behaviour over a large number of collisions is detected.

The CONNIE experiment

NASA Astrophysics Data System (ADS)

Aguilar-Arevalo, A.; Bertou, X.; Bonifazi, C.; Butner, M.; Cancelo, G.; Castaneda Vazquez, A.; Cervantes Vergara, B.; Chavez, C. R.; Da Motta, H.; D'Olivo, J. C.; Dos Anjos, J.; Estrada, J.; Fernandez Moroni, G.; Ford, R.; Foguel, A.; Hernandez Torres, K. P.; Izraelevitch, F.; Kavner, A.; Kilminster, B.; Kuk, K.; Lima, H. P., Jr.; Makler, M.; Molina, J.; Moreno-Granados, G.; Moro, J. M.; Paolini, E. E.; Sofo Haro, M.; Tiffenberg, J.; Trillaud, F.; Wagner, S.

2016-10-01

The CONNIE experiment uses fully depleted, high resistivity CCDs as particle detectors in an attempt to measure for the first time the Coherent Neutrino-Nucleus Elastic Scattering of antineutrinos from a nuclear reactor with silicon nuclei. This talk, given at the XV Mexican Workshop on Particles and Fields (MWPF), discussed the potential of CONNIE to perform this measurement, the installation progress at the Angra dos Reis nuclear power plant, as well as the plans for future upgrades.

The CONNIE experiment

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

Aguilar-Arevalo, A.; et al.

2016-10-19

The CONNIE experiment uses fully depleted, high resistivity CCDs as particle detectors in an attempt to measure for the first time the Coherent Neutrino-Nucleus Elastic Scattering of antineutrinos from a nuclear reactor with silicon nuclei.This talk, given at the XV Mexican Workshop on Particles and Fields (MWPF), discussed the potential of CONNIE to perform this measurement, the installation progress at the Angra dos Reis nuclear power plant, as well as the plans for future upgrades.

Project X

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

Holmes, Steve; Alber, Russ; Asner, David

2013-06-23

Particle physics has made enormous progress in understanding the nature of matter and forces at a fundamental level and has unlocked many mysteries of our world. The development of the Standard Model of particle physics has been a magnificent achievement of the field. Many deep and important questions have been answered and yet many mysteries remain. The discovery of neutrino oscillations, discrepancies in some precision measurements of Standard-Model processes, observation of matter-antimatter asymmetry, the evidence for the existence of dark matter and dark energy, all point to new physics beyond the Standard Model. The pivotal developments of our field, includingmore » the latest discovery of the Higgs Boson, have progressed within three interlocking frontiers of research – the Energy, Intensity and Cosmic frontiers – where discoveries and insights in one frontier powerfully advance the other frontiers as well.« less

Size segregation in a granular bore

NASA Astrophysics Data System (ADS)

Edwards, A. N.; Vriend, N. M.

2016-10-01

We investigate the effect of particle-size segregation in an upslope propagating granular bore. A bidisperse mixture of particles, initially normally graded, flows down an inclined chute and impacts with a closed end. This impact causes the formation of a shock in flow thickness, known as a granular bore, to travel upslope, leaving behind a thick deposit. This deposit imprints the local segregated state featuring both pure and mixed regions of particles as a function of downstream position. The particle-size distribution through the depth is characterized by a thin purely small-particle layer at the base, a significant linear transition region, and a thick constant mixed-particle layer below the surface, in contrast to previously observed S-shaped steady-state concentration profiles. The experimental observations agree with recent progress that upward and downward segregation of large and small particles respectively is asymmetric. We incorporate the three-layer, experimentally observed, size-distribution profile into a depth-averaged segregation model to modify it accordingly. Numerical solutions of this model are able to match our experimental results and therefore motivate the use of a more general particle-size distribution profile.

Recent Advances in Multi-component Particles Assembly.

PubMed

Guo, Dan; Song, Yanlin

2018-03-09

Particles assembly and co-assembly have been research frontiers in chemistry and material science in the past few decades. To achieve a large variety of intricate structures and functional materials, remarkable progress has been made in the particle assembly principles and strategies. It can be summarized that the particle assembly is driven by intrinsic interparticle interaction or the external control. In this article, we focus on binary or ternary particles co-assembly and review the principles and feasible strategies. These advances have led to new disciplines of microfabrication technology and material engineering. Although remarked achievement on particle-based structures has been made, it is still challenging to fully develop general and facile strategies to precisely control the one-dimensional (1D) co-assembly. This article reviews the recent development on multi-component particles co-assembly, which significantly increases structural complexity and functional diversity. In particular, we highlight the advances in the particles co-assembly of well-ordered 1D binary superstructures by liquid soft confinement. Finally, prospective outlook for future trends in this field is proposed. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Understanding of Particle Acceleration by Foreshock Transients (invited)

NASA Astrophysics Data System (ADS)

Liu, T. Z.; Angelopoulos, V.; Hietala, H.; Lu, S.; Wilson, L. B., III

2017-12-01

Although plasma shocks are known to be a major particle accelerator at Earth's environment (e.g., the bow shock) and elsewhere in the universe, how particles are accelerated to very large energies compared to the shock potential is still not fully understood. Significant new information on such acceleration in the vicinity of Earth's bow shock has recently emerged due to the availability of multi-point observations, in particular from Cluster and THEMIS. These have revealed numerous types of foreshock transients, formed by shock-reflected ions, which could play a crucial role in particle pre-acceleration, i.e. before the particles reach the shock to be subjected again to even further acceleration. Foreshock bubbles (FBs) and hot flow anomalies (HFAs), are a subset of such foreshock transients that are especially important due to their large spatial scale (1-10 Earth radii), and their ability to have global effects at Earth.s geospace. These transients can accelerate particles that can become a particle source for the parent shock. Here we introduce our latest progress in understanding particle acceleration by foreshock transients including their statistical characteristics and acceleration mechanisms.

Understanding of Particle Acceleration by Foreshock Transients

NASA Astrophysics Data System (ADS)

Liu, T. Z.; Angelopoulos, V.; Hietala, H.; Lu, S.; Wilson, L. B., III

2017-12-01

Although plasma shocks are known to be a major particle accelerator at Earth's environment (e.g., the bow shock) and elsewhere in the universe, how particles are accelerated to very large energies compared to the shock potential is still not fully understood. Significant new information on such acceleration in the vicinity of Earth's bow shock has recently emerged due to the availability of multi-point observations, in particular from Cluster and THEMIS. These have revealed numerous types of foreshock transients, formed by shock-reflected ions, which could play a crucial role in particle pre-acceleration, i.e. before the particles reach the shock to be subjected again to even further acceleration. Foreshock bubbles (FBs) and hot flow anomalies (HFAs), are a subset of such foreshock transients that are especially important due to their large spatial scale (1-10 Earth radii), and their ability to have global effects at Earth's geospace. These transients can accelerate particles that can become a particle source for the parent shock. Here we introduce our latest progress in understanding particle acceleration by foreshock transients including their statistical characteristics and acceleration mechanisms.

Nuclear Power Plant Mechanical Component Flooding Fragility Experiments Status

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

Pope, C. L.; Savage, B.; Johnson, B.

This report describes progress on Nuclear Power Plant mechanical component flooding fragility experiments and supporting research. The progress includes execution of full scale fragility experiments using hollow-core doors, design of improvements to the Portal Evaluation Tank, equipment procurement and initial installation of PET improvements, designation of experiments exploiting the improved PET capabilities, fragility mathematical model development, Smoothed Particle Hydrodynamic simulations, wave impact simulation device research, and pipe rupture mechanics research.

Optical spectroscopy of interplanetary dust collected in the earth's stratosphere

NASA Technical Reports Server (NTRS)

Fraundorf, P.; Patel, R. I.; Shirck, J.; Walker, R. M.; Freeman, J. J.

1980-01-01

Optical absorption spectra of interplanetary dust particles 2-30 microns in size collected in the atmosphere at an altitude of 20 km by inertial impactors mounted on NASA U-2 aircraft are reported. Fourier transform absorption spectroscopy of crushed samples of the particles reveals a broad feature in the region 1300-800 kaysers which has also been found in meteorite and cometary dust spectra, and a weak iron crystal field absorption band at approximately 9800 kaysers, as is observed in meteorites. Work is currently in progress to separate the various components of the interplanetary dust particles in order to evaluate separately their contributions to the absorption.

Progress in tagged neutron beams for cargo inspections

NASA Astrophysics Data System (ADS)

Pesente, S.; Nebbia, G.; Viesti, G.; Daniele, F.; Fabris, D.; Lunardon, M.; Moretto, S.; Nad, K.; Sudac, D.; Valkovic, V.

2007-08-01

The use of neutron beams produced via the D + T reaction and tagged by the associated particle technique has been recently applied to cargo container inspections. In the EURITRACK project, a portable sealed-tube neutron generator has been designed and built to deliver 14 MeV neutron beams tagged by a matrix of 64 YAP:Ce alpha-particle detectors read by a multi-anode HAMAMATSU H8500 Photomultiplier Tube. The performances of this alpha-particle detector have been determined as a function of the count rate at the Rudjer Boskovic Institute, Zagreb (Croatia). Moreover, tests of the final detector operated inside the sealed-tube neutron generator are fully satisfactory.

Magnetohydrodynamic Particle Acceleration Processes: SSX Experiments, Theory, and Astrophysical Applications

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

Brown, Michael R.

2006-11-16

Project Title: Magnetohydrodynamic Particle Acceleration Processes: SSX Experiments, Theory, and Astrophysical Applications PI: Michael R. Brown, Swarthmore College The purpose of the project was to provide theoretical and modeling support to the Swarthmore Spheromak Experiment (SSX). Accordingly, the theoretical effort was tightly integrated into the SSX experimental effort. During the grant period, Michael Brown and his experimental collaborators at Swarthmore, with assistance from W. Matthaeus as appropriate, made substantial progress in understanding the physics SSX plasmas.

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

Colò, G., E-mail: gianluca.colo@mi.infn.it; Baldo, M.; Bortignon, P. F.

In this contribution, we report some recent progress in our understanding of particle-vibration coupling (PVC) in nuclei. In particular, we first review the formal development that has allowed some of us to deduce the PVC equations within the Green’s functionmethod. Applications are then discussed, both in the case of single-particle states and giant resonances in magic nuclei. We also present a new model that extends the PVC ansatz and is meant to account for the complete low-lying spectra of odd nuclei.

Recent progress in the transition radiation detector techniques

NASA Technical Reports Server (NTRS)

Yuan, L. C. L.

1973-01-01

A list of some of the major experimental achievements involving charged particles in the relativistic region are presented. With the emphasis mainly directed to the X-ray region, certain modes of application of the transition radiation for the identification and separation of relativistic charged particles are discussed. Some recent developments in detection techniques and improvements in detector performances are presented. Experiments were also carried out to detect the dynamic radiation, but no evidence of such an effect was observed.

Small particle aerosol inoculation of cowpox Brighton Red in rhesus monkeys results in a severe respiratory disease

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

Johnson, Reed F.; Hammoud, Dima A.; Lackemeyer, Matthew G.

Cowpox virus (CPXV) inoculation of nonhuman primates (NHPs) has been suggested as an alternate model for smallpox (Kramski et al., 2010, PLoS One, 5, e10412). Previously, we have demonstrated that intrabronchial inoculation of CPXV-Brighton Red (CPXV-BR) into cynomolgus monkeys resulted in a disease that shared many similarities to smallpox; however, severe respiratory tract disease was observed (Smith et al., 2011, J. Gen. Virol.). Here we describe the course of disease after small particle aerosol exposure of rhesus monkeys using computed tomography (CT) to monitor respiratory disease progression. Subjects developed a severe respiratory disease that was uniformly lethal at 5.7 log{submore » 10} PFU of CPXV-BR. CT indicated changes in lung architecture that correlated with changes in peripheral blood monocytes and peripheral oxygen saturation. While the small particle aerosol inoculation route does not accurately mimic human smallpox, the data suggest that CT can be used as a tool to monitor real-time disease progression for evaluation of animal models for human diseases. - Highlights: • Small particle aerosol exposure of rhesus results in a severe respiratory disease. • CT findings correlated with peripheral oxygen saturation and monocyte increases. • Virus dissemination was limited and mainly confined to the respiratory tract. • CT provides insight into pathogenesis to aid development of animal models of disease.« less

Rheological changes induced by clast fragmentation in debris flows

NASA Astrophysics Data System (ADS)

Caballero, Lizeth; Sarocchi, Damiano; Soto, Enrique; Borselli, Lorenzo

2014-09-01

On the basis of rotating drum analogue experiments, we describe a fragmentation process acting within debris flows during transport and its influence on rheologic behavior. Our hypothesis is based on a detailed textural analysis including granulometry, clast morphology, and rheologic properties of the fluid matrix. Results of the experiments point out that breakage of certain granulometric classes produces fine particles like fine sand and silt. The population growth of fine clasts with time leads to an increase in yield strength and viscosity that progressively modifies the rheologic behavior. From a textural point of view, this is reflected in a bimodal granulometric distribution. Up to now this characteristic has been explained as the effect of bulking and/or sedimentation processes during transport. Our experimental results show that the type of fragmentation depends on particle size and is the consequence of strong clast-clast interaction and clast-fluid interactions. Coarse particles develop small fractures which cause the loss of sharp edges and asperities. Medium-sized particles develop through-going fractures that cause them to break apart. The latter process explains why intermediate granulometric classes progressively diminish with time in debris flows. Analogue experiments enable us to study the efficacy of clast fragmentation in modifying the textural character and flow behavior of debris flows without the influence of external factors such as erosion and sedimentation. The obtained results constitute the base of a new approach for modeling debris flow dynamics.

Study of aniline polymerization reactions through the particle size formation in acidic and neutral medium

NASA Astrophysics Data System (ADS)

Aribowo, Slamet; Hafizah, Mas Ayu Elita; Manaf, Azwar; Andreas

2018-04-01

In the present paper, we reported particle size kinetic studies on the conducting polyaniline (PANI) which synthesized through a chemical oxidative polymerization technique from aniline monomer. PANI was prepared using ammonium persulfate (APS) as oxidizing agent which carried out in acidic and neutral medium at various batch temperatures of respectively 20, 30 and 50 °C. From the studies, it was noticed that the complete polymerization reaction progressed within 480 minutes duration time. The pH of the solution during reaction kinetic reached values 0.8 - to 1.2 in acidic media, while in the neutral media the pH value reached values 3.8 - 4.9. The batch temperature controlled the polymerization reaction in which the reaction progressing, which followed by the temperature rise of solution above the batch temperature before settled down to the initial temperature. An increment in the batch temperature gave highest rise in the solution temperature for the two media which cannot be more than 50 °C. The final product of polymerization reaction was PANI confirmed by Fourier Transform Infra-Red (FTIR) spectrophotometer for molecule structure identification. The averages particle size of PANI which carried out in the two different media is evidently similar in the range 30 - 40 μm and insensitive to the batch temperature. However, the particle size of PANI which obtained from the polymerization reaction at a batch temperature of 50 °C under acidic condition reached ˜53.1 μm at the tip of the propagation stage which started in the first 5 minutes. The size is obviously being the largest among the batch temperatures. Whereas, under neutral condition the particle size is much larger which reached the size 135 μm at the batch temperature of 20 °C. It is concluded that the particle size formation during the polymerization reaction being one of the important parameter to determine particle growing of polymer which indicated the reaction kinetics mechanism of synthesize polyaniline.

Modeling of particle radiative properties in coal combustion depending on burnout

NASA Astrophysics Data System (ADS)

Gronarz, Tim; Habermehl, Martin; Kneer, Reinhold

2017-04-01

In the present study, absorption and scattering efficiencies as well as the scattering phase function of a cloud of coal particles are described as function of the particle combustion progress. Mie theory for coated particles is applied as mathematical model. The scattering and absorption properties are determined by several parameters: size distribution, spectral distribution of incident radiation and spectral index of refraction of the particles. A study to determine the influence of each parameter is performed, finding that the largest effect is due to the refractive index, followed by the effect of size distribution. The influence of the incident radiation profile is negligible. As a part of this study, the possibility of applying a constant index of refraction is investigated. Finally, scattering and absorption efficiencies as well as the phase function are presented as a function of burnout with the presented model and the results are discussed.

The Features of Self-Assembling Organic Bilayers Important to the Formation of Anisotropic Inorganic Materials in Microgravity Conditions

NASA Technical Reports Server (NTRS)

Talham, Daniel R.; Adair, James H.

1999-01-01

There is a growing need for inorganic anisotropic particles in a variety of materials science applications. Structural, optical, and electrical properties can be greatly augmented by the fabrication of composite materials with anisotropic microstructures or with anisotropic particles uniformly dispersed in an isotropic matrix. Examples include structural composites, magnetic and optical recording media, photographic film, certain metal and ceramic alloys, and display technologies including flat panel displays. While considerable progress has been made toward developing an understanding of the synthesis of powders composed of monodispersed, spherical particles, these efforts have not been transferred to the synthesis of anisotropic nanoparticles. The major objective of the program is to develop a fundamental understanding of the growth of anisotropic particles at organic templates, with emphasis on the chemical and structural aspects of layered organic assemblies that contribute to the formation of anisotropic inorganic particles.

Statistical theory of correlations in random packings of hard particles.

PubMed

Jin, Yuliang; Puckett, James G; Makse, Hernán A

2014-05-01

A random packing of hard particles represents a fundamental model for granular matter. Despite its importance, analytical modeling of random packings remains difficult due to the existence of strong correlations which preclude the development of a simple theory. Here, we take inspiration from liquid theories for the n-particle angular correlation function to develop a formalism of random packings of hard particles from the bottom up. A progressive expansion into a shell of particles converges in the large layer limit under a Kirkwood-like approximation of higher-order correlations. We apply the formalism to hard disks and predict the density of two-dimensional random close packing (RCP), ϕ(rcp) = 0.85 ± 0.01, and random loose packing (RLP), ϕ(rlp) = 0.67 ± 0.01. Our theory also predicts a phase diagram and angular correlation functions that are in good agreement with experimental and numerical data.

Tailoring particle translocation via dielectrophoresis in pore channels

PubMed Central

Tanaka, Shoji; Tsutsui, Makusu; Theodore, Hu; Yuhui, He; Arima, Akihide; Tsuji, Tetsuro; Doi, Kentaro; Kawano, Satoyuki; Taniguchi, Masateru; Kawai, Tomoji

2016-01-01

Understanding and controlling electrophoretic motions of nanoscopic objects in fluidic channels are a central challenge in developing nanopore technology for molecular analyses. Although progress has been made in slowing the translocation velocity to meet the requirement for electrical detections of analytes via picoampere current measurements, there exists no method useful for regulating particle flows in the transverse directions. Here, we report the use of dielectrophoresis to manipulate the single-particle passage through a solid-state pore. We created a trap field by applying AC voltage between electrodes embedded in a low-aspect-ratio micropore. We demonstrated a traffic control of particles to go through center or near side surface via the voltage frequency. We also found enhanced capture efficiency along with faster escaping speed of particles by virtue of the AC-mediated electroosmosis. This method is compatible with nanopore sensing and would be widely applied for reducing off-axis effects to achieve single-molecule identification. PMID:27527126

Assembly of Reconfigurable Colloidal Structures by Multidirectional Field-Induced Interactions.

PubMed

Bharti, Bhuvnesh; Velev, Orlin D

2015-07-28

Field-directed colloidal assembly has shown remarkable recent progress in increasing the complexity, degree of control, and multiscale organization of the structures. This has largely been achieved by using particles of complex shapes and polarizabilites (Janus, patchy, shaped, and faceted). We review the fundamentals of the interactions leading to the directed assembly of such structures, the ways to simulate the dynamics of the process, and the effect of particle size, shape, and properties on the type of structure obtained. We discuss how directional polarization interactions induced by external electric and magnetic fields can be used to assemble complex particles or particle mixtures into lattices of tailored structure. Examples of such systems include isotropic and anisotropic shaped particles with surface patches, which form networks and crystals of unusual symmetry by dipolar, quadrupolar, and multipolar interactions in external fields. The emerging trends in making reconfigurable and dynamic structures are discussed.

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.

Simulating Biomass Fast Pyrolysis at the Single Particle Scale

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

Ciesielski, Peter; Wiggins, Gavin; Daw, C Stuart

2017-07-01

Simulating fast pyrolysis at the scale of single particles allows for the investigation of the impacts of feedstock-specific parameters such as particle size, shape, and species of origin. For this reason particle-scale modeling has emerged as an important tool for understanding how variations in feedstock properties affect the outcomes of pyrolysis processes. The origins of feedstock properties are largely dictated by the composition and hierarchical structure of biomass, from the microstructural porosity to the external morphology of milled particles. These properties may be accounted for in simulations of fast pyrolysis by several different computational approaches depending on the level ofmore » structural and chemical complexity included in the model. The predictive utility of particle-scale simulations of fast pyrolysis can still be enhanced substantially by advancements in several areas. Most notably, considerable progress would be facilitated by the development of pyrolysis kinetic schemes that are decoupled from transport phenomena, predict product evolution from whole-biomass with increased chemical speciation, and are still tractable with present-day computational resources.« less

Tracking the shape-dependent sintering of platinum-rhodium model catalysts under operando conditions

NASA Astrophysics Data System (ADS)

Hejral, Uta; Müller, Patrick; Balmes, Olivier; Pontoni, Diego; Stierle, Andreas

2016-03-01

Nanoparticle sintering during catalytic reactions is a major cause for catalyst deactivation. Understanding its atomic-scale processes and finding strategies to reduce it is of paramount scientific and economic interest. Here, we report on the composition-dependent three-dimensional restructuring of epitaxial platinum-rhodium alloy nanoparticles on alumina during carbon monoxide oxidation at 550 K and near-atmospheric pressures employing in situ high-energy grazing incidence x-ray diffraction, online mass spectrometry and a combinatorial sample design. For platinum-rich particles our results disclose a dramatic reaction-induced height increase, accompanied by a corresponding reduction of the total particle surface coverage. We find this restructuring to be progressively reduced for particles with increasing rhodium composition. We explain our observations by a carbon monoxide oxidation promoted non-classical Ostwald ripening process during which smaller particles are destabilized by the heat of reaction. Its driving force lies in the initial particle shape which features for platinum-rich particles a kinetically stabilized, low aspect ratio.

Physical characteristics of cometary dust from dynamical studies - A review

NASA Technical Reports Server (NTRS)

Sekanina, Z.

1980-01-01

Progress made in the determination of the physical characteristics of cometary dust particles from studies of dust tail dynamics is reviewed. Applications of the combined dynamical photometric approach of Finson and Probstein (1968) to studies of cometary tails exhibiting continuous light intensity variations are discussed, with attention given to determinations of the particle-size-related distribution function of the solar radiation pressure exerted on the particles, the contribution of comets to the interplanetary dust, calculations of dust ejection rates and a Monte Carlo approach to the analysis of dust tails. Investigations of dust streamers and striae, which are believed to be related to comet outbursts entailing brief but sharp enhancements of dust production, are then reviewed, with particular attention given to observations of Comet West 1976 VI. Finally, the question of cometary particle type is addressed, and it is pointed out that the presence of submicron absorbing particles in the striae of Comet West is not incompatible with the presence of micron-size dielectric particles in the inner coma.

Working Group Report: Sensors

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

Artuso, M.; et al.,

Sensors play a key role in detecting both charged particles and photons for all three frontiers in Particle Physics. The signals from an individual sensor that can be used include ionization deposited, phonons created, or light emitted from excitations of the material. The individual sensors are then typically arrayed for detection of individual particles or groups of particles. Mounting of new, ever higher performance experiments, often depend on advances in sensors in a range of performance characteristics. These performance metrics can include position resolution for passing particles, time resolution on particles impacting the sensor, and overall rate capabilities. In additionmore » the feasible detector area and cost frequently provides a limit to what can be built and therefore is often another area where improvements are important. Finally, radiation tolerance is becoming a requirement in a broad array of devices. We present a status report on a broad category of sensors, including challenges for the future and work in progress to solve those challenges.« less

Sensor Compendium - A Snowmass Whitepaper-

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

Artuso, M.; Battaglia, M.; Bolla, G.

Sensors play a key role in detecting both charged particles and photons for all three frontiers in Particle Physics. The signals from an individual sensor that can be used include ionization deposited, phonons created, or light emitted from excitations of the material. The individual sensors are then typically arrayed for detection of individual particles or groups of particles. Mounting of new, ever higher performance experiments, often depend on advances in sensors in a range of performance characteristics. These performance metrics can include position resolution for passing particles, time resolution on particles impacting the sensor, and overall rate capabilities. In additionmore » the feasible detector area and cost frequently provides a limit to what can be built and therefore is often another area where improvements are important. Finally, radiation tolerance is becoming a requirement in a broad array of devices. We present a status report on a broad category of sensors, including challenges for the future and work in progress to solve those challenges.« less

Crystallization by Particle Attachment in Synthetic, Biogenic, and Geologic Environments

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

De Yoreo, James J.; Gilbert, Pupa U.; Sommerdijk, Nico

Field and laboratory observations show that crystals commonly form by the addition and attachment of particles that range from multi-ion complexes to fully formed nanoparticles. These non-classical pathways to crystallization are diverse, in contrast to classical models that consider the addition of monomeric chemical species. We review progress toward understanding crystal growth by particle attachment processes and show that multiple pathways result from the interplay of free energy landscapes and reaction dynamics. Much remains unknown about the fundamental aspects; particularly the relationships between solution structure, interfacial forces, and particle motion. Developing a predictive description that connects molecular details to ensemblemore » behavior will require revisiting long-standing interpretations of crystal formation in synthetic systems and patterns of mineralization in natural environments.« less

Detectors for Linear Colliders: Calorimetry at a Future Electron-Positron Collider (3/4)

ScienceCinema

Thomson, Mark

2018-04-16

Calorimetry will play a central role in determining the physics reach at a future e+e- collider. The requirements for calorimetry place the emphasis on achieving an excellent jet energy resolution. The currently favoured option for calorimetry at a future e+e- collider is the concept of high granularity particle flow calorimetry. Here granularity and a high pattern recognition capability is more important than the single particle calorimetric response. In this lecture I will describe the recent progress in understanding the reach of high granularity particle flow calorimetry and the related R&D; efforts which concentrate on test beam demonstrations of the technological options for highly granular calorimeters. I will also discuss alternatives to particle flow, for example the technique of dual readout calorimetry.

Simultaneous purification and storage of hydrogen

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

Hynek, S.; Fuller, W.; Weber, R.

1998-08-01

Specially coated magnesium particles have been shown to selectively absorb hydrogen from a hydrogen-rich gas stream such as reformate. These coated magnesium particles can store the absorbed hydrogen as required and subsequently deliver pure hydrogen, just as uncoated magnesium particles can. These coated magnesium particles could be used in a device that accepts a steady stream of reformate, as from a methane reformer, stores the selectively absorbed hydrogen indefinitely, and delivers purified hydrogen on demand. Unfortunately, this coating (magnesium nitride) has been shown to degrade over a period of several weeks, so that the magnesium within evidences progressively lower storagemore » capacity. The authors are investigating two other coatings, one of which might be applicable to hydridable metals other than magnesium, to replace magnesium nitride.« less

Processes of energy deposition by heavy-particle and electron impact. Final progress report

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

Salop, A.; Smith, F.T.

1978-04-18

Progress is reported in three areas of reasearch during the present period: K-shell ionization in high energy collisions of heavy ions with light target atoms using the sudden (Magnus) approximation, K-L level matching phenomena associated with K-shell vacancy production in heavy-ion collisions, and studies of low energy collisions of electrons with molecules using semi-classical perturbation theory. A brief discussion of each of these activities is given.

The Progress of Research Project for Magnetized Target Fusion in China

NASA Astrophysics Data System (ADS)

Yang, Xian-Jun

2015-11-01

The fusion of magnetized plasma called Magnetized Target Fusion (MTF) is a hot research area recently. It may significantly reduce the cost and size. Great progress has been achieved in past decades around the world. Five years ago, China initiated the MTF project and has gotten some progress as follows: 1. Verifying the feasibility of ignition of MTF by means of first principle and MHD simulation; 2. Generating the magnetic field over 1400 Tesla, which can be suppress the heat conduction from charged particles, deposit the energy of alpha particle to promote the ignition process, and produce the stable magnetized plasma for the target of ignition; 3. The imploding facility of FP-1 can put several Mega Joule energy to the solid liner of about ten gram in the range of microsecond risen time, while the simulating tool has been developed for design and analysis of the process; 4. The target of FRC can be generated by ``YG 1 facility'' while some simulating tools have be developed. Next five years, the above theoretical work and the experiments of MTF may be integrated to step up as the National project, which may make my term play an important lead role and be supposed to achieve farther progress in China. Supported by the National Natural Science Foundation of China under Grant No 11175028.

Prophylaxis and Immunization in Mice by Use of Virus-Free Defective T Particles to Protect Against Intracerebral Infection by Vesicular Stomatitis Virus

PubMed Central

Doyle, Michael; Holland, John J.

1973-01-01

Defective interfering T particles of vesicular stomatitis virus provide remarkable protection against viral disease and death when introduced intracerebrally in large numbers along with an otherwise rapidly fatal low dose of standard infectious virus. This profound prophylactic effect of defective T particles is due to homologous autointerference since it is serotype-specific and interferon is not induced. This protective effect can be demonstrated only with preparations of T particles that have been purified completely free of infectious virions. When pure T particles are injected intracerebrally along with large doses of infectious virus, they convert an otherwise rapidly fatal disease process to a slowly progressing virus infection that generally terminates in death after many days of wasting disease and paralysis. Intracerebral injection of virus-free T particles alone is apparently innocuous to mice and stimulates immunity to massive doses of homologous infectious virus. In vitro, virus-free T particles at extremely high multiplicities depress cellular RNA and protein synthesis and kill BHK21 cells in culture, but do not exhibit such effects at moderately high multiplicities. PMID:4352972

Modeling compressible multiphase flows with dispersed particles in both dense and dilute regimes

NASA Astrophysics Data System (ADS)

McGrath, T.; St. Clair, J.; Balachandar, S.

2018-05-01

Many important explosives and energetics applications involve multiphase formulations employing dispersed particles. While considerable progress has been made toward developing mathematical models and computational methodologies for these flows, significant challenges remain. In this work, we apply a mathematical model for compressible multiphase flows with dispersed particles to existing shock and explosive dispersal problems from the literature. The model is cast in an Eulerian framework, treats all phases as compressible, is hyperbolic, and satisfies the second law of thermodynamics. It directly applies the continuous-phase pressure gradient as a forcing function for particle acceleration and thereby retains relaxed characteristics for the dispersed particle phase that remove the constituent material sound velocity from the eigenvalues. This is consistent with the expected characteristics of dispersed particle phases and can significantly improve the stable time-step size for explicit methods. The model is applied to test cases involving the shock and explosive dispersal of solid particles and compared to data from the literature. Computed results compare well with experimental measurements, providing confidence in the model and computational methods applied.

On the role of particle cracking in flow and fracture of metal matrix composites

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

Brockenbrough, J.R.; Zok, F.W.

1995-01-01

The flow response of particle-reinforced metal matrix composites is studied using finite element methods. Unit cells containing either intact or cracked particles in a power law hardening matrix are used to determine the corresponding asymptotic flow strengths. The effects of the hardening exponent and the elastic mismatch between the particles and the matrix on the flow response are examined. For comparison, the flow response of power law hardening solids containing penny-shaped cracks is also evaluated. The latter results are found to be in reasonable agreement with those corresponding to composites that contain low volume fractions of cracked particles. The asymptoticmore » results are used to develop a one-dimensional constitutive law for composites which undergo progressive damage during tensile straining. This law is used to evaluate the strain at the onset of plastic instability. It is proposed that the instability strain be used as a measure of tensile ductility when the particle content is low and the particles are uniformly distributed through the matrix.« less

New measurements for hadrontherapy and space radiation: biology

NASA Technical Reports Server (NTRS)

Blakely, E. A.

2001-01-01

The dual goals of optimizing clinical efficacy of hadrontherapy and determining radiation risk estimates for space research have intersected to a common focus for investigation of the biological effects of charged particles. This paper briefly highlights recent international progress at accelerator facilities engaged in both biological and clinical studies of the effects of particle beams, primarily protons, carbon and iron ions. Basic mechanisms of molecular, cellular and tissue responses continue under investigation for radiations with a range of ionization densities. Late normal tissue effects, including the risk of cancer in particular, are of importance for both research fields. International cooperation has enhanced the rate of progress as evidenced by recent publications. Specific areas of biomedical research related to the biological radiotoxicity of critical organs (especially the central nervous system), individual radiosensitivities to radiation carcinogenesis, and the analysis of effects in mixed radiation fields still require more research. Recommendations for addressing these issues are made.

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

Liakh, Dmitry I

While the formalism of multiresolution analysis (MRA), based on wavelets and adaptive integral representations of operators, is actively progressing in electronic structure theory (mostly on the independent-particle level and, recently, second-order perturbation theory), the concepts of multiresolution and adaptivity can also be utilized within the traditional formulation of correlated (many-particle) theory which is based on second quantization and the corresponding (generally nonorthogonal) tensor algebra. In this paper, we present a formalism called scale-adaptive tensor algebra (SATA) which exploits an adaptive representation of tensors of many-body operators via the local adjustment of the basis set quality. Given a series of locallymore » supported fragment bases of a progressively lower quality, we formulate the explicit rules for tensor algebra operations dealing with adaptively resolved tensor operands. The formalism suggested is expected to enhance the applicability and reliability of local correlated many-body methods of electronic structure theory, especially those directly based on atomic orbitals (or any other localized basis functions).« less

ATMOSPHERIC AEROSOL SOURCE-RECEPTOR RELATIONSHIPS: THE ROLE OF COAL-FIRED POWER PLANTS

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

Allen L. Robinson; Spyros N. Pandis; Cliff I. Davidson

2004-12-01

This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of March 2004 through August 2004. Significant progress was made this project period on the analysis of ambient data, source apportionment, and deterministic modeling activities. Results highlighted in this report include evaluation of the performance of PMCAMx+ for an air pollution episode in the Eastern US, an emission profile for a coke production facility, ultrafine particle composition during a nucleation event, and a new hybrid approach for source apportionment. An agreement was reached with a utility to characterize fine particle and mercury emissionsmore » from a commercial coal fired power. Research in the next project period will include source testing of a coal fired power plant, source apportionment analysis, emission scenario modeling with PMCAMx+, and writing up results for submission as journal articles.« less

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

Gorelenkov, Nikolai N

The area of energetic particle (EP) physics of fusion research has been actively and extensively researched in recent decades. The progress achieved in advancing and understanding EP physics has been substantial since the last comprehensive review on this topic by W.W. Heidbrink and G.J. Sadler [1]. That review coincided with the start of deuterium-tritium (DT) experiments on Tokamak Fusion Test reactor (TFTR) and full scale fusion alphas physics studies. Fusion research in recent years has been influenced by EP physics in many ways including the limitations imposed by the "sea" of Alfven eigenmodes (AE) in particular by the toroidicityinduced AEsmore » (TAE) modes and reversed shear Alfven (RSAE). In present paper we attempt a broad review of EP physics progress in tokamaks and spherical tori since the first DT experiments on TFTR and JET (Joint European Torus) including helical/stellarator devices. Introductory discussions on basic ingredients of EP physics, i.e. particle orbits in STs, fundamental diagnostic techniques of EPs and instabilities, wave particle resonances and others are given to help understanding the advanced topics of EP physics. At the end we cover important and interesting physics issues toward the burning plasma experiments such as ITER (International Thermonuclear Experimental Reactor).« less

Aliphatic and aromatic plant biopolymer dynamics in soil particles isolated from sequential density fractionation

NASA Astrophysics Data System (ADS)

Caldwell, B.; Filley, T.; Sollins, P.; Lajtha, K.; Swanston, C.; Kleber, M.; Kramer, M.

2007-12-01

A recent multi-layer-based soil organic matter-mineral interaction mechanistic model to describe the nature of soil organic matter-mineral surface mechanism for soil organic matter stabilization predicts that proteinaceous and aliphatic materials establish the core of strong binding-interactions upon which other organic matter is layered. A key methodology providing data underpinning this hypothesis is sequential density fractionation where soil is partitioned into particles of increasing density with the assumption that a partial control on organic matter distribution through density series is the thickness of its layering. Four soils of varying mineralogy and texture were investigated for their biopolymer, isotopic, and mineralogical properties. Light fractions (<1.8 g/cm3), although dominanted by organic detritus, did not always contain the highest concentration of lignin and substituted fatty acids from cutin and suberin while heavier fractions, 1.8-2.6 g/cm3, exhibited a progressive decrease in concentration in plant derived biopolymers with density. Extractable lignin phenols exhibited a progressive oxidation state with density. The concentration of biopolymers roughly mirrored the C:N ratio of soil particles which dropped consistently with increasing particle density. Although, in all soils, both lignin phenols and SFA concentration generally decreased with increasing density the ratio SFA/lignin varied with density and depending upon the soil. All soils, except the oxisol, exhibited an increase in SFA with respect to lignin suggesting a selective stabilization of those material with respect to lignin. In the oxisol, which showed little variation in its hematite dominated mineralogy across density, SFA/lignin remained constant, potentially indicating a greater capacity to stabilize lignin in that system. Interestingly, the lignin oxidation state increased with density in the oxisol. Given the variation in soil character, the consistency in these trends it suggests a general phenomenon of progressive decay in plant derived material with thinness of mineral coating but an overall relative increase in aliphatic character-all consistent with the multi-layer model.

Progress in the Development and Utilization of Ferrography

DTIC Science & Technology

1975-12-31

in greater detail in Figs 5 and 6, could be due to some form of chemical attack or the incomplete balling- up of many small particles. The size of...When, however, the wearing surfaces started to fail and become rougher with time, the maximum size of the particles increased by as much as one or two orders of magnitude. .. I ...Prepared - or : Office cf Naval Research 31 December 1975 DISTRIBUTED BY: mi] National Technical Information Service U. S. DEPARTMENT OF COMMERCE

Particle-gas dynamics in the protoplanetary nebula

NASA Technical Reports Server (NTRS)

Cuzzi, Jeffrey N.; Champney, Joelle M.; Dobrovolskis, Anthony R.

1991-01-01

In the past year we made significant progress in improving our fundamental understanding of the physics of particle-gas dynamics in the protoplanetary nebula. Having brought our code to a state of fairly robust functionality, we devoted significant effort to optimizing it for running long cases. We optimized the code for vectorization to the extent that it now runs eight times faster than before. The following subject areas are covered: physical improvements to the model; numerical results; Reynolds averaging of fluid equations; and modeling of turbulence and viscosity.

Kinetic modeling of particle dynamics in H- negative ion sources (invited)

NASA Astrophysics Data System (ADS)

Hatayama, A.; Shibata, T.; Nishioka, S.; Ohta, M.; Yasumoto, M.; Nishida, K.; Yamamoto, T.; Miyamoto, K.; Fukano, A.; Mizuno, T.

2014-02-01

Progress in the kinetic modeling of particle dynamics in H- negative ion source plasmas and their comparisons with experiments are reviewed, and discussed with some new results. Main focus is placed on the following two topics, which are important for the research and development of large negative ion sources and high power H- ion beams: (i) Effects of non-equilibrium features of EEDF (electron energy distribution function) on H- production, and (ii) extraction physics of H- ions and beam optics.

A theoretical perspective on particle acceleration by interplanetary shocks and the Solar Energetic Particle problem

NASA Astrophysics Data System (ADS)

Verkhoglyadova, Olga P.; Zank, Gary P.; Li, Gang

2015-02-01

Understanding the physics of Solar Energetic Particle (SEP) events is of importance to the general question of particle energization throughout the cosmos as well as playing a role in the technologically critical impact of space weather on society. The largest, and often most damaging, events are the so-called gradual SEP events, generally associated with shock waves driven by coronal mass ejections (CMEs). We review the current state of knowledge about particle acceleration at evolving interplanetary shocks with application to SEP events that occur in the inner heliosphere. Starting with a brief outline of recent theoretical progress in the field, we focus on current observational evidence that challenges conventional models of SEP events, including complex particle energy spectra, the blurring of the distinction between gradual and impulsive events, and the difference inherent in particle acceleration at quasi-parallel and quasi-perpendicular shocks. We also review the important problem of the seed particle population and its injection into particle acceleration at a shock. We begin by discussing the properties and characteristics of non-relativistic interplanetary shocks, from their formation close to the Sun to subsequent evolution through the inner heliosphere. The association of gradual SEP events with shocks is discussed. Several approaches to the energization of particles have been proposed, including shock drift acceleration, diffusive shock acceleration (DSA), acceleration by large-scale compression regions, acceleration by random velocity fluctuations (sometimes known as the "pump mechanism"), and others. We review these various mechanisms briefly and focus on the DSA mechanism. Much of our emphasis will be on our current understanding of the parallel and perpendicular diffusion coefficients for energetic particles and models of plasma turbulence in the vicinity of the shock. Because of its importance both to the DSA mechanism itself and to the particle composition of SEP events, we address in some detail the injection problem. Although steady-state models can improve our understanding of the diffusive shock acceleration mechanism, SEP events are inherently time-dependent. We therefore review the time-dependent theory of DSA in some detail, including estimating possible maximum particle energies and particle escape from the shock complex. We also discuss generalizations of the diffusive transport approach to modeling particle acceleration by considering a more general description based on the focused transport equation. The escape of accelerated particles from the shock requires that their subsequent transport in the interplanetary medium be modeled and the consequence of interplanetary transport can lead to the complex spectra and compositional profiles that are observed frequently. The different approaches to particle transport in the inner heliosphere are reviewed. The various numerical models that have been developed to solve the gradual SEP problem are reviewed. Explicit comparisons of modeling results with observations of large SEP events are discussed. A summary of current progress and the outlook on the SEP problem and remaining open questions conclude the review.

Nature of crystalline particle assembly in ring shaped colloidal stains from concentrated dispersions

NASA Astrophysics Data System (ADS)

Shao, Fenfen; Huynh, Trang; Somers, Anthony; Liu, Boyin; Fu, Jing; Muradoglu, Murat; Ng, Tuck Wah

2014-05-01

The drying of colloidal droplet suspensions is important in many realms of practical application and has sustained the interest of researchers over two decades. The arrangements of polystyrene and silica beads, both of diameter 1 μm, 10% by volume of solid deposited on normal glass (hydrophilic), and silicone (hydrophobic) surfaces evaporated from a suspension volume of 3 μL, were investigated. Doughnut shape depositions were found, imputing the influence of strong central circulation flows that resulted in three general regions. In the central region which had strong particle build-up, the top most layers of particle arrangement was confirmed to be disordered using power spectrum and radial distribution function analysis. On closer examination, this appeared more like frustrated attempts to crystallize into larger grains rather than beads arranging in a disordered fashion throughout the piling process. With an adapted micro-bulldozing operation to progressively remove layers of particles from the heap, we found that the later efforts to crystallize through lateral capillary inter-particle forces were liable to be undone once the particles contacted the disorganized particles underneath, which were formed out of the jamming of fast particles arriving at the surface.

Lunar Dust Characterization Activity at GRC

NASA Technical Reports Server (NTRS)

Street, Kenneth W.

2008-01-01

The fidelity of lunar simulants as compared to actual regolith is evaluated using Figures of Merit (FOM) which are based on four criteria: Particle Size, Particle Shape, Composition, and Density of the bulk material. In practice, equipment testing will require other information about both the physical properties (mainly of the dust fraction) and composition as a function of particle size. At Glenn Research Center (GRC) we are involved in evaluating a number of simulant properties of consequence to testing of lunar equipment in a relevant environment, in order to meet Technology Readiness Level (TRL) 6 criteria. Bulk regolith has been characterized for many decades, but surprisingly little work has been done on the dust fraction (particles less than 20 micrometers in diameter). GRC is currently addressing the information shortfall by characterizing the following physical properties: Particle Size Distribution, Adhesion, Abrasivity, Surface Energy, Magnetic Susceptibility, Tribocharging and Surface Chemistry/Reactivity. Since some of these properties are also dependent on the size of the particles we have undertaken the construction of a six stage axial cyclone particle separator to fractionate dust into discrete particle size distributions for subsequent evaluation of these properties. An introduction to this work and progress to date will be presented.

Influence of Particle Morphology on 3D Kinematic Behavior and Strain Localization of Sheared Sand

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

Alshibli, Khalid A.; Jarrar, Maha F.; Druckrey, Andrew M.

The constitutive behavior of sheared sand is highly influenced by particle morphology, gradation, mineralogy, specimen density, loading condition, stress path, and boundary conditions. The current literature lacks a three-dimensional (3D) systematic experimental study that investigates the influence of particle morphology, confining pressure, and specimen density on the failure mode of sheared sand. In this paper, surface texture, roundness, and sphericity of three uniform sands and glass beads with similar grain size were quantified by using 3D images of particles. In situ nondestructive 3D synchrotron microcomputed tomography (SMT) was used to monitor the deformation of medium-dense and very dense dry sandmore » specimens that were tested under axisymmetric triaxial loading condition at 15 and 400 kPa confining pressures. The particles were identified and tracked in 3D as shearing progressed within the specimens, and maps of incremental particle translation and rotation were developed and used to uncover the relationship between particle morphology, specimen density, and confining pressure on the deformation and failure mode of sheared sand. This paper discusses the relationship between the failure mode and particle morphology, specimen density, and confining pressure.« less

Er-doped lead borate glasses and transparent glass ceramics for near-infrared luminescence and up-conversion applications.

PubMed

Pisarski, Wojciech A; Goryczka, Tomasz; Pisarska, Joanna; Ryba-Romanowski, Witold

2007-03-15

Lead borate based glasses have been analyzed using Raman and infrared spectroscopy. The formation of different borate groups and the direction of BO3 <--> BO4 conversion strongly depends on the PbO- and/or PbF2-to-B2O3 ratio in chemical composition. PbF2-PbO-B2O3 based glasses containing Er3+ ions have been studied after annealing. The orthorhombic PbF2 crystallites are formed during thermal treatment, which was evidenced by X-ray diffraction analysis. Near-infrared luminescence at 1530 nm and green up-conversion at 545 nm have been registered for samples before and after annealing. The luminescence bands correspond to 4I13/2-4I15/2 and 4S3/2-4I15/2 transitions of Er3+ ions, respectively. In comparison to the precursor glasses, the luminescence intensities are higher in the studied transparent oxyfluoride glass ceramics. Simultaneously, the half-width of the luminescence lines slightly decreases. It can be the evidence that a small amount of the Er3+ ions is incorporated into the orthorhombic PbF2 phase.

White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals

NASA Astrophysics Data System (ADS)

Li, Chenxia; Xu, Shiqing; Ye, Rengguang; Deng, Degang; Hua, Youjie; Zhao, Shilong; Zhuang, Songlin

2011-04-01

Ho3+/Tm3+/Yb3+ tri-doped glass ceramics with white light emitting have been developed and demonstrated. Pumped by 980 nm laser diode (LD), intensive red, green and blue up-conversions (UC) were obtained. The green emission is assigned to Ho3+ ion and the blue emission is assigned to Tm3+ ion, whereas the red emission is the combination contribution of the Ho3+ and Tm3+ ions. The RGB intensities could be adjusted by tuning the rare-earth ion concentration and pump power intensity. Thus, multicolor of the luminescence, including perfect white light with CIE-X=0.329 and CIE-Y=0.342 in the 1931 CIE chromaticity diagram can be obtained in 0.15 Ho3+/0.2Tm3+/3Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals pumped by a single infrared laser diode source of 980 nm at 500 mW. The up-conversion luminescence mechanism of Yb3+ sensitize Ho3+ and Tm3+ ions and the energy transfer from Ho3+ to Tm3+ in oxy-fluoride silicate glass ceramics were analyzed.

Ytterbium-doped glass-ceramics for optical refrigeration.

PubMed

Filho, Elton Soares de Lima; Krishnaiah, Kummara Venkata; Ledemi, Yannick; Yu, Ye-Jin; Messaddeq, Younes; Nemova, Galina; Kashyap, Raman

2015-02-23

We report for the first time the characterization of glass-ceramics for optical refrigeration. Ytterbium-doped nanocrystallites were grown in an oxyfluoride glass matrix of composition 2YbF(3):30SiO(2)-15Al(2)O(3)-25CdF(2)-22PbF(2)-4YF(3), forming bulk glass-ceramics at three different crystalisation levels. The samples are compared with a corresponding uncrystalised (glass) sample, as well as a Yb:YAG sample which has presented optical cooling. The measured X-ray diffraction spectra, and thermal capacities of the samples are reported. We also report for the first time the use of Yb:YAG as a reference for absolute photometric quantum efficiency measurement, and use the same setup to characterize the glass and glass-ceramic samples. The cooling figure-of-merit was measured by optical calorimetry using a fiber Bragg grating and found to depend on the level of crystallization of the sample, and that samples with nanocrystallites result in higher quantum efficiency and lower background absorption than the pure-glass sample. In addition to laser-induced cooling, the glass-ceramics have the potential to serve as a reference for quantum efficiency measurements.

FERMILAB ACCELERATOR R&D PROGRAM TOWARDS INTENSITY FRONTIER ACCELERATORS : STATUS AND PROGRESS

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

Shiltsev, Vladimir

2016-11-15

The 2014 P5 report indicated the accelerator-based neutrino and rare decay physics research as a centrepiece of the US domestic HEP program at Fermilab. Operation, upgrade and development of the accelerators for the near- term and longer-term particle physics program at the Intensity Frontier face formidable challenges. Here we discuss key elements of the accelerator physics and technology R&D program toward future multi-MW proton accelerators and present its status and progress. INTENSITY FRONTIER ACCELERATORS

Using field-particle correlations to study auroral electron acceleration in the LAPD

NASA Astrophysics Data System (ADS)

Schroeder, J. W. R.; Howes, G. G.; Skiff, F.; Kletzing, C. A.; Carter, T. A.; Vincena, S.; Dorfman, S.

2017-10-01

Resonant nonlinear Alfvén wave-particle interactions are believed to contribute to the acceleration of auroral electrons. Experiments in the Large Plasma Device (LAPD) at UCLA have been performed with the goal of providing the first direct measurement of this nonlinear process. Recent progress includes a measurement of linear fluctuations of the electron distribution function associated with the production of inertial Alfvén waves in the LAPD. These linear measurements have been analyzed using the field-particle correlation technique to study the nonlinear transfer of energy between the Alfvén wave electric fields and the electron distribution function. Results of this analysis indicate collisions alter the resonant signature of the field-particle correlation, and implications for resonant Alfvénic electron acceleration in the LAPD are considered. This work was supported by NSF, DOE, and NASA.

Size and shape effects on diffusion and absorption of colloidal particles near a partially absorbing sphere: implications for uptake of nanoparticles in animal cells.

PubMed

Shi, Wendong; Wang, Jizeng; Fan, Xiaojun; Gao, Huajian

2008-12-01

A mechanics model describing how a cell membrane with diffusive mobile receptors wraps around a ligand-coated cylindrical or spherical particle has been recently developed to model the role of particle size in receptor-mediated endocytosis. The results show that particles in the size range of tens to hundreds of nanometers can enter cells even in the absence of clathrin or caveolin coats. Here we report further progress on modeling the effects of size and shape in diffusion, interaction, and absorption of finite-sized colloidal particles near a partially absorbing sphere. Our analysis indicates that, from the diffusion and interaction point of view, there exists an optimal hydrodynamic size of particles, typically in the nanometer regime, for the maximum rate of particle absorption. Such optimal size arises as a result of balance between the diffusion constant of the particles and the interaction energy between the particles and the absorbing sphere relative to the thermal energy. Particles with a smaller hydrodynamic radius have larger diffusion constant but weaker interaction with the sphere while larger particles have smaller diffusion constant but stronger interaction with the sphere. Since the hydrodynamic radius is also determined by the particle shape, an optimal hydrodynamic radius implies an optimal size as well as an optimal aspect ratio for a nonspherical particle. These results show broad agreement with experimental observations and may have general implications on interaction between nanoparticles and animal cells.

Size and shape effects on diffusion and absorption of colloidal particles near a partially absorbing sphere: Implications for uptake of nanoparticles in animal cells

NASA Astrophysics Data System (ADS)

Shi, Wendong; Wang, Jizeng; Fan, Xiaojun; Gao, Huajian

2008-12-01

A mechanics model describing how a cell membrane with diffusive mobile receptors wraps around a ligand-coated cylindrical or spherical particle has been recently developed to model the role of particle size in receptor-mediated endocytosis. The results show that particles in the size range of tens to hundreds of nanometers can enter cells even in the absence of clathrin or caveolin coats. Here we report further progress on modeling the effects of size and shape in diffusion, interaction, and absorption of finite-sized colloidal particles near a partially absorbing sphere. Our analysis indicates that, from the diffusion and interaction point of view, there exists an optimal hydrodynamic size of particles, typically in the nanometer regime, for the maximum rate of particle absorption. Such optimal size arises as a result of balance between the diffusion constant of the particles and the interaction energy between the particles and the absorbing sphere relative to the thermal energy. Particles with a smaller hydrodynamic radius have larger diffusion constant but weaker interaction with the sphere while larger particles have smaller diffusion constant but stronger interaction with the sphere. Since the hydrodynamic radius is also determined by the particle shape, an optimal hydrodynamic radius implies an optimal size as well as an optimal aspect ratio for a nonspherical particle. These results show broad agreement with experimental observations and may have general implications on interaction between nanoparticles and animal cells.

Visualization of the African swine fever virus infection in living cells by incorporation into the virus particle of green fluorescent protein-p54 membrane protein chimera

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

Hernaez, Bruno; Escribano, Jose M.; Alonso, Covadonga

2006-06-20

Many stages of African swine fever virus infection have not yet been studied in detail. To track the behavior of African swine fever virus (ASFV) in the infected cells in real time, we produced an infectious recombinant ASFV (B54GFP-2) that expresses and incorporates into the virus particle a chimera of the p54 envelope protein fused to the enhanced green fluorescent protein (EGFP). The incorporation of the fusion protein into the virus particle was confirmed immunologically and it was determined that p54-EGFP was fully functional by confirmation that the recombinant virus made normal-sized plaques and presented similar growth curves to themore » wild-type virus. The tagged virus was visualized as individual fluorescent particles during the first stages of infection and allowed to visualize the infection progression in living cells through the viral life cycle by confocal microscopy. In this work, diverse potential applications of B54GFP-2 to study different aspects of ASFV infection are shown. By using this recombinant virus it was possible to determine the trajectory and speed of intracellular virus movement. Additionally, we have been able to visualize for first time the ASFV factory formation dynamics and the cytophatic effect of the virus in live infected cells. Finally, we have analyzed virus progression along the infection cycle and infected cell death as time-lapse animations.« less

SITE OF PARTICLE SELECTION IN A BIVALVE MOLLUSK. (R825551)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Region 5: Ohio Canton - Massilon Adequate Letter (2/10/2010)

EPA Pesticide Factsheets

This is a letter from John Mooney, Chief, to Jenifer Hunter regarding Ohio's SIP for the Establishment of Interim Progress for the Fine Particle National Ambient Air Quality and early fine particulate (PM2.5) transportation conformity emission budgets.

PERSONAL EXPOSURE TO PARTICLES IN BANSKA BYSTRICA, SLOVAKIA. (R825173)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

SYSTEMIC INTERACTIONS BETWEEN INHALED ULTRAFINE PARTICLES AND ENDOTOXIN. (R826784)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

ATMOSPHERIC AEROSOL SOURCE-RECEPTOR RELATIONSHIPS: THE ROLE OF COAL-FIRED POWER PLANTS

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

Allen L. Robinson; Spyros N. Pandis; Cliff I. Davidson

2004-04-01

This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of September 2003 through February 2004. Significant progress was made this project period on the analysis of ambient data, source apportionment, and deterministic modeling activities. Results highlighted in this report include chemical fractionation of the organic fraction to quantify the ratio of organic mass to organic carbon (OM/OC). The average OM/OC ratio for the 31 samples analyzed so far is 1.89, ranging between 1.62 and 2.53, which is consistent with expectations for an atmospherically processed regional aerosol. Analysis of the single particle datamore » reveals that a on a particles in Pittsburgh consist of complex mixture of primary and secondary components. Approximately 79% of all particles measured with the instrument containing some form of carbon, with Carbonaceous Ammonium Nitrate (54.43%) being the dominant particle class. PMCAMx predictions were compared with data from more than 50 sites of the STN network located throughout the Eastern United States for the July 2001 period. OC and sulfate concentrations predicted by PMCAMx are within {+-}30% of the observed concentration at most of these sites. Spherical Aluminum Silicate particle concentrations (SAS) were used to estimate the contribution of primary coal emissions to fine particle levels at the central monitoring site. Primary emissions from coal combustion contribute on average 0.44 {+-} 0.3 {micro}g/m{sup 3} to PM{sub 2.5} at the site or 1.4 {+-} 1.3% of the total PM{sub 2.5} mass. Chemical mass balance analysis was performed to apportion the primary organic aerosol. About 70% of the primary OC emissions are from vehicular sources, with the gasoline contribution being on average three times greater than the diesel emissions in the summer.« less

Particle and nuclear physics instrumentation and its broad connections

DOE PAGES

Demarteau, Marcel; Lipton, Ron; Nicholson, Howard; ...

2016-12-20

Subatomic physics shares with other basic sciences the need to innovate, invent, and develop tools, techniques, and technologies to carry out its mission to explore the nature of matter, energy, space, and time. In some cases, entire detectors or technologies developed specifically for particle physics research have been adopted by other fields of research or in commercial applications. In most cases, however, the development of new devices and technologies by particle physics for its own research has added value to other fields of research or to applications beneficial to society by integrating them in the existing technologies. Thus, detector researchmore » and development has not only advanced the current state of technology for particle physics, but has often advanced research in other fields of science and has underpinned progress in numerous applications in medicine and national security. At the same time particle physics has profited immensely from developments in industry and applied them to great benefit for the use of particle physics detectors. Finally, this symbiotic relationship has seen strong mutual benefits with sometimes unexpected far reach.« less

Particle and nuclear physics instrumentation and its broad connections

NASA Astrophysics Data System (ADS)

Demarteau, M.; Lipton, R.; Nicholson, H.; Shipsey, I.

2016-10-01

Subatomic physics shares with other basic sciences the need to innovate, invent, and develop tools, techniques, and technologies to carry out its mission to explore the nature of matter, energy, space, and time. In some cases, entire detectors or technologies developed specifically for particle physics research have been adopted by other fields of research or in commercial applications. In most cases, however, the development of new devices and technologies by particle physics for its own research has added value to other fields of research or to applications beneficial to society by integrating them in the existing technologies. Thus, detector research and development has not only advanced the current state of technology for particle physics, but has often advanced research in other fields of science and has underpinned progress in numerous applications in medicine and national security. At the same time particle physics has profited immensely from developments in industry and applied them to great benefit for the use of particle physics detectors. This symbiotic relationship has seen strong mutual benefits with sometimes unexpected far reach.

Particle and nuclear physics instrumentation and its broad connections

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

Demarteau, Marcel; Lipton, Ron; Nicholson, Howard

Subatomic physics shares with other basic sciences the need to innovate, invent, and develop tools, techniques, and technologies to carry out its mission to explore the nature of matter, energy, space, and time. In some cases, entire detectors or technologies developed specifically for particle physics research have been adopted by other fields of research or in commercial applications. In most cases, however, the development of new devices and technologies by particle physics for its own research has added value to other fields of research or to applications beneficial to society by integrating them in the existing technologies. Thus, detector researchmore » and development has not only advanced the current state of technology for particle physics, but has often advanced research in other fields of science and has underpinned progress in numerous applications in medicine and national security. At the same time particle physics has profited immensely from developments in industry and applied them to great benefit for the use of particle physics detectors. Finally, this symbiotic relationship has seen strong mutual benefits with sometimes unexpected far reach.« less

Capture of Hypervelocity Particles with Low-Density Aerogel

NASA Technical Reports Server (NTRS)

Hoerz, Friedrich; Cintala, Mark J.; Zolensky, Michael E.; Bernhard, Ronald B.; Haynes, Gerald; See, Thomas H.; Tsou, Peter; Brownlee, Donald E.

1998-01-01

Recent impact experiments conducted at Johnson Space Center supported a space-exposed flight instrument called the orbital debris collector (ODC) to see whether SiO2 acrogel performed adequately as a collector to capture cosmic dust particles and/or manmade debris, or whether additional development is needed. The first ODC was flown aboard the Mir for 18 months, while the second will be flown aboard a spacecraft (Stardust, to be launched in 1999) that will encounter the comet Wild 2 and return to Earth. Aerogels are highly porous materials that decelerate high-velocity particles without substantial melting or modifications to the particles' components; in other denser materials, these particles would melt or vaporize upon impact. The experimental data in this report must be considered somewhat qualitative because they are characterized by substantial, if not intolerable, scatter, possibly due to experimental difficulties in duplicating given sets of initial impact conditions. Therefore, this report is a chronological guide of the experimenters' attempts, difficulties, progress, and evaluations for future tests.

Particle-Size-Exclusion Clogging Regimes in Porous Media

NASA Astrophysics Data System (ADS)

Gerber, G.; Rodts, S.; Aimedieu, P.; Faure, P.; Coussot, P.

2018-04-01

From observations of the progressive deposition of noncolloidal particles by geometrical exclusion effects inside a 3D model porous medium, we get a complete dynamic view of particle deposits over a full range of regimes from transport over a long distance to clogging and caking. We show that clogging essentially occurs in the form of an accumulation of elements in pore size clusters, which ultimately constitute regions avoided by the flow. The clusters are dispersed in the medium, and their concentration (number per volume) decreases with the distance from the entrance; caking is associated with the final stage of this effect (for a critical cluster concentration at the entrance). A simple probabilistic model, taking into account the impact of clogging on particle transport, allows us to quantitatively predict all these trends up to a large cluster concentration, based on a single parameter: the clogging probability, which is a function of the confinement ratio. This opens the route towards a unification of the different fields of particle transport, clogging, caking, and filtration.

Modeling of Cluster-Induced Turbulence in Particle-Laden Channel Flow

NASA Astrophysics Data System (ADS)

Baker, Michael; Capecelatro, Jesse; Kong, Bo; Fox, Rodney; Desjardins, Olivier

2017-11-01

A phenomenon often observed in gas-solid flows is the formation of mesoscale clusters of particles due to the relative motion between the solid and fluid phases that is sustained through the dampening of collisional particle motion from interphase momentum coupling inside these clusters. The formation of such sustained clusters, leading to cluster-induced turbulence (CIT), can have a significant impact in industrial processes, particularly in regards to mixing, reaction progress, and heat transfer. Both Euler-Lagrange (EL) and Euler-Euler anisotropic Gaussian (EE-AG) approaches are used in this work to perform mesoscale simulations of CIT in fully developed gas-particle channel flow. The results from these simulations are applied in the development of a two-phase Reynolds-Averaged Navier-Stokes (RANS) model to capture the wall-normal flow characteristics in a less computationally expensive manner. Parameters such as mass loading, particle size, and gas velocity are varied to examine their respective impact on cluster formation and turbulence statistics. Acknowledging support from the NSF (AN:1437865).

Particle motions beneath irrotational water waves

NASA Astrophysics Data System (ADS)

Bakhoday-Paskyabi, Mostafa

2015-08-01

Neutral and buoyant particle motions in an irrotational flow are investigated under the passage of linear, nonlinear gravity, and weakly nonlinear solitary waves at a constant water depth. The developed numerical models for the particle trajectories in a non-turbulent flow incorporate particle momentum, size, and mass (i.e., inertial particles) under the influence of various surface waves such as Korteweg-de Vries waves which admit a three parameter family of periodic cnoidal wave solutions. We then formulate expressions of mass-transport velocities for the neutral and buoyant particles. A series of test cases suggests that the inertial particles possess a combined horizontal and vertical drifts from the locations of their release, with a fall velocity as a function of particle material properties, ambient flow, and wave parameters. The estimated solutions exhibit good agreement with previously explained particle behavior beneath progressive surface gravity waves. We further investigate the response of a neutrally buoyant water parcel trajectories in a rotating fluid when subjected to a series of wind and wave events. The results confirm the importance of the wave-induced Coriolis-Stokes force effect in both amplifying (destroying) the pre-existing inertial oscillations and in modulating the direction of the flow particles. Although this work has mainly focused on wave-current-particle interaction in the absence of turbulence stochastic forcing effects, the exercise of the suggested numerical models provides additional insights into the mechanisms of wave effects on the passive trajectories for both living and nonliving particles such as swimming trajectories of plankton in non-turbulent flows.

Novel changes in discoidal high density lipoprotein morphology: a molecular dynamics study.

PubMed

Catte, Andrea; Patterson, James C; Jones, Martin K; Jerome, W Gray; Bashtovyy, Denys; Su, Zhengchang; Gu, Feifei; Chen, Jianguo; Aliste, Marcela P; Harvey, Stephen C; Li, Ling; Weinstein, Gilbert; Segrest, Jere P

2006-06-15

ApoA-I is a uniquely flexible lipid-scavenging protein capable of incorporating phospholipids into stable particles. Here we report molecular dynamics simulations on a series of progressively smaller discoidal high density lipoprotein particles produced by incremental removal of palmitoyloleoylphosphatidylcholine via four different pathways. The starting model contained 160 palmitoyloleoylphosphatidylcholines and a belt of two antiparallel amphipathic helical lipid-associating domains of apolipoprotein (apo) A-I. The results are particularly compelling. After a few nanoseconds of molecular dynamics simulation, independent of the starting particle and method of size reduction, all simulated double belts of the four lipidated apoA-I particles have helical domains that impressively approximate the x-ray crystal structure of lipid-free apoA-I, particularly between residues 88 and 186. These results provide atomic resolution models for two of the particles produced by in vitro reconstitution of nascent high density lipoprotein particles. These particles, measuring 95 angstroms and 78 angstroms by nondenaturing gradient gel electrophoresis, correspond in composition and in size/shape (by negative stain electron microscopy) to the simulated particles with molar ratios of 100:2 and 50:2, respectively. The lipids of the 100:2 particle family form minimal surfaces at their monolayer-monolayer interface, whereas the 50:2 particle family displays a lipid pocket capable of binding a dynamic range of phospholipid molecules.

Novel Changes in Discoidal High Density Lipoprotein Morphology: A Molecular Dynamics Study

PubMed Central

Catte, Andrea; Patterson, James C.; Jones, Martin K.; Jerome, W. Gray; Bashtovyy, Denys; Su, Zhengchang; Gu, Feifei; Chen, Jianguo; Aliste, Marcela P.; Harvey, Stephen C.; Li, Ling; Weinstein, Gilbert; Segrest, Jere P.

2006-01-01

ApoA-I is a uniquely flexible lipid-scavenging protein capable of incorporating phospholipids into stable particles. Here we report molecular dynamics simulations on a series of progressively smaller discoidal high density lipoprotein particles produced by incremental removal of palmitoyloleoylphosphatidylcholine via four different pathways. The starting model contained 160 palmitoyloleoylphosphatidylcholines and a belt of two antiparallel amphipathic helical lipid-associating domains of apolipoprotein (apo) A-I. The results are particularly compelling. After a few nanoseconds of molecular dynamics simulation, independent of the starting particle and method of size reduction, all simulated double belts of the four lipidated apoA-I particles have helical domains that impressively approximate the x-ray crystal structure of lipid-free apoA-I, particularly between residues 88 and 186. These results provide atomic resolution models for two of the particles produced by in vitro reconstitution of nascent high density lipoprotein particles. These particles, measuring 95 Å and 78 Å by nondenaturing gradient gel electrophoresis, correspond in composition and in size/shape (by negative stain electron microscopy) to the simulated particles with molar ratios of 100:2 and 50:2, respectively. The lipids of the 100:2 particle family form minimal surfaces at their monolayer-monolayer interface, whereas the 50:2 particle family displays a lipid pocket capable of binding a dynamic range of phospholipid molecules. PMID:16581834

Velocity and displacement statistics in a stochastic model of nonlinear friction showing bounded particle speed

NASA Astrophysics Data System (ADS)

Menzel, Andreas M.

2015-11-01

Diffusion of colloidal particles in a complex environment such as polymer networks or biological cells is a topic of high complexity with significant biological and medical relevance. In such situations, the interaction between the surroundings and the particle motion has to be taken into account. We analyze a simplified diffusion model that includes some aspects of a complex environment in the framework of a nonlinear friction process: at low particle speeds, friction grows linearly with the particle velocity as for regular viscous friction; it grows more than linearly at higher particle speeds; finally, at a maximum of the possible particle speed, the friction diverges. In addition to bare diffusion, we study the influence of a constant drift force acting on the diffusing particle. While the corresponding stationary velocity distributions can be derived analytically, the displacement statistics generally must be determined numerically. However, as a benefit of our model, analytical progress can be made in one case of a special maximum particle speed. The effect of a drift force in this case is analytically determined by perturbation theory. It will be interesting in the future to compare our results to real experimental systems. One realization could be magnetic colloidal particles diffusing through a shear-thickening environment such as starch suspensions, possibly exposed to an external magnetic field gradient.

Induction of micronuclei in human fibroblasts across the Bragg curve of energetic heavy ions

NASA Technical Reports Server (NTRS)

Hada, Megumi; Rusek, Adam; Cucinotta, Francis A.; Wu, Honglu

2006-01-01

The space environment consists of a varying field of radiation particles including high energy ions, with spacecraft shielding material providing the major protection to astronauts from harmful exposure. Unlike low-L or X-rays, the presence of shielding does not always reduce the radiation risks for energetic charged particle exposure. Although the dose delivered by the charged particle increases sharply as the particle approaches the Bragg peak, the Bragg curve does not necessarily represent the biological damage along the particle traversal. The "biological Bragg curve" is dependent on the energy and the type of the primary particle, and may vary for different biological endpoints. To investigate "biological Bragg curves", we analyzed micronuclei (MN) induction along the particle traversal of Si and Fe ions at incident energies of 300 MeV/nucleon and 1 GeV/nucleon. A quantitative biological response curve did not reveal an increased yield of MN at the location of the Bragg peak. However, the ratio of mono-to bi-nucleated cells, which indicates inhibition in cell progression, increased at the Bragg peak location. These results confirm the hypothesis that "over kill" at the Bragg peak will affect the outcome of other biological endpoints.

FINE PARTICLE AND GASEOUS EMISSION RATES FROM RESIDENTIAL WOOD COMBUSTION. (R826237)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

SYSTEMIC INTERACTIONS BETWEEN INHALED ULTRAFINE PARTICLES AND ENDOTOXIN. (R827354C004)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

INTERSTRAIN VARIATION IN MURINE SUSCEPTIBILITY TO INHALED ACID-COATED PARTICLES. (R825815)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

GENETIC LINKAGE ANALYSIS OF SUSCEPTIBILITY TO PARTICLE EXPOSURE IN MICE. (R825815)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Scientific Discovery through Advanced Computing in Plasma Science

NASA Astrophysics Data System (ADS)

Tang, William

2005-03-01

Advanced computing is generally recognized to be an increasingly vital tool for accelerating progress in scientific research during the 21st Century. For example, the Department of Energy's ``Scientific Discovery through Advanced Computing'' (SciDAC) Program was motivated in large measure by the fact that formidable scientific challenges in its research portfolio could best be addressed by utilizing the combination of the rapid advances in super-computing technology together with the emergence of effective new algorithms and computational methodologies. The imperative is to translate such progress into corresponding increases in the performance of the scientific codes used to model complex physical systems such as those encountered in high temperature plasma research. If properly validated against experimental measurements and analytic benchmarks, these codes can provide reliable predictive capability for the behavior of a broad range of complex natural and engineered systems. This talk reviews recent progress and future directions for advanced simulations with some illustrative examples taken from the plasma science applications area. Significant recent progress has been made in both particle and fluid simulations of fine-scale turbulence and large-scale dynamics, giving increasingly good agreement between experimental observations and computational modeling. This was made possible by the combination of access to powerful new computational resources together with innovative advances in analytic and computational methods for developing reduced descriptions of physics phenomena spanning a huge range in time and space scales. In particular, the plasma science community has made excellent progress in developing advanced codes for which computer run-time and problem size scale well with the number of processors on massively parallel machines (MPP's). A good example is the effective usage of the full power of multi-teraflop (multi-trillion floating point computations per second) MPP's to produce three-dimensional, general geometry, nonlinear particle simulations which have accelerated progress in understanding the nature of plasma turbulence in magnetically-confined high temperature plasmas. These calculations, which typically utilized billions of particles for thousands of time-steps, would not have been possible without access to powerful present generation MPP computers and the associated diagnostic and visualization capabilities. In general, results from advanced simulations provide great encouragement for being able to include increasingly realistic dynamics to enable deeper physics insights into plasmas in both natural and laboratory environments. The associated scientific excitement should serve to stimulate improved cross-cutting collaborations with other fields and also to help attract bright young talent to the computational science area.

Tracking inorganic foulants irreversibly accumulated on low-pressure membranes for treating surface water.

PubMed

Yamamura, Hiroshi; Kimura, Katsuki; Higuchi, Kumiko; Watanabe, Yoshimasa; Ding, Qing; Hafuka, Akira

2015-12-15

While low-pressure membrane filtration processes (i.e., microfiltration and ultrafiltration) can offer precise filtration than sand filtration, they pose the problem of reduced efficiency due to membrane fouling. Although many studies have examined membrane fouling by organic substances, there is still not enough data available concerning membrane fouling by inorganic substances. The present research investigated changes in the amounts of inorganic components deposited on the surface of membrane filters over time using membrane specimens sampled thirteen times at arbitrary time intervals during pilot testing in order to determine the mechanism by which irreversible fouling by inorganic substances progresses. The experiments showed that the inorganic components that primarily contribute to irreversible fouling vary as filtration continues. It was discovered that, in the initial stage of operation, the main membrane-fouling substance was iron, whereas the primary membrane-fouling substances when operation finished were manganese, calcium, and silica. The amount of iron accumulated on the membrane increased up to the thirtieth day of operation, after which it reached a steady state. After the accumulation of iron became static, subsequent accumulation of manganese was observed. The fact that the removal rates of these inorganic components also increased gradually shows that the size of the exclusion pores of the membrane filter narrows as operation continues. Studying particle size distributions of inorganic components contained in source water revealed that while many iron particles are approximately the same size as membrane pores, the fraction of manganese particles slightly smaller than the pores in diameter was large. From these results, it is surmised that iron particles approximately the same size as the pores block them soon after the start of operation, and as the membrane pores narrow with the development of fouling, they become further blocked by manganese particles approximately the same size as the narrowed pores. Calcium and silica are assumed to accumulate on the membrane due to their cross-linking action and/or complex formation with organic substances such as humic compounds. The present research is the first to clearly show that the inorganic components that contribute to membrane fouling differ according to the stage of membrane fouling progression; the information obtained by this research should enable chemical cleaning or operational control in accordance with the stage of membrane fouling progression. Copyright © 2015 Elsevier Ltd. All rights reserved.

Charged particle and magnetic field research in space

NASA Technical Reports Server (NTRS)

1972-01-01

Research completed and in progress is described, related publications and reports are listed, and abstracts of papers and talks on results of the research are given. The charged particle research centered on OGO-5 and OGO-6 electron spectrometer data, and theoretical radiation belt studies. Work on the ATS-1 magnetometer project included development of production data reduction programs, development of spectral analysis procedures, and scientific studies of ULF waves at synchronous orbit. The magnetic fields research also included work on the Mariner project and theoretical studies on the solar wind.

Laboratory Astrophysics Using High Intensity Particle and Photon Beams

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

Chen, Pisin

History has shown that the symbiosis between direct observations and laboratory studies is instrumental in the progress of astrophysics. Recent years have seen growing interests in the laboratory investigation of astrophysical phenomena that can be addressed by high densities and advancement of technologies in lasers as well as high-energy particle beams. We will give examples on how frontier phenomena such as black holes, supernovae, gamma ray bursts, ultra high-energy cosmic rays, etc., can be investigated in the laboratory setting. Finally, we describe a possible laboratory astrophysics facility to be developed at SLAC.

Precision Crystal Calorimeters in High Energy Physics

ScienceCinema

Ren-Yuan Zhu

2017-12-09

Precision crystal calorimeters traditionally play an important role in high energy physics experiments. In the last two decades, it faces a challenge to maintain its precision in a hostile radiation environment. This paper reviews the performance of crystal calorimeters constructed for high energy physics experiments and the progress achieved in understanding crystal’s radiation damage as well as in developing high quality scintillating crystals for particle physics. Potential applications of new generation scintillating crystals of high density and high light yield, such as LSO and LYSO, in particle physics experiments is also discussed.

SR-BI selective lipid uptake: subsequent metabolism of acute phase HDL.

PubMed

de Beer, Maria C; Webb, Nancy R; Whitaker, Nathan L; Wroblewski, Joanne M; Jahangiri, Anisa; van der Westhuyzen, Deneys R; de Beer, Frederick C

2009-09-01

The purpose of this study was to investigate the interaction of SAA and SR-BI in remodeling of acute phase HDL (AP HDL). We used SAA and SR-BI adenoviral vector expression models to study the interaction between these entities. SR-BI processing of mouse AP HDL generated progressively smaller discreet HDL particles with distinct apolipoprotein compositions. SR-BI actions segregated apolipoproteins with the smallest particles containing only apoA-I. Larger remnants contained apoA-I, apoA-II, and SAA. Small apoA-I only particles failed to associate with preformed HDL, whereas larger remnants readily did. The presence of SAA on SR-BI-processed HDL particles propelled apoA-I to a small lipid-poor form and accelerated apoA-I catabolism. Data indicate that after core and surface HDL lipid perturbation by SR-BI, SAA propels apoA-I to a small lipid-poor form while accelerating HDL metabolism.

Characterizing and controlling industrial dust: a case study in small particle measurement.

PubMed

Combes, Richard S; Warren, D Alan

2005-07-01

Instrumentation used to measure characteristics of fine particles entrained in gas or suspended in aerosols provides information needed to develop valid regulations for emission sources and to support the design of control technologies. This case study offers a brief history of "micromeritics," a term used by early researchers to describe the science of small particles, and the related invention of laboratory instruments for characterizing very fine particles. The historical view provides insights into the role that Progressive Era government agencies played in advancing esoteric science and applying this knowledge to the regulation of workplace air pollution. Micromeritics instrumentation developed in conjunction with federal research now has many commercial applications worldwide, with characterizing airborne pollutants only a minor one. However, the continuing advances in the micromeritics field provide important laboratory measurement capabilities to environmental research organizations, such as the National Institute for Occupational Safety and Health (NIOSH).

Studies of High Energy Particle Astrophysics

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

Nitz, David F; Fick, Brian E

This report covers the progress of the Michigan Technological University particle astrophysics group during the period April 15th, 2011 through April 30th, 2014. The principal investigator is Professor David Nitz. Professor Brian Fick is the Co-PI. The focus of the group is the study of the highest energy cosmic rays using the Pierre Auger Observatory. The major goals of the Pierre Auger Observatory are to discover and understand the source or sources of cosmic rays with energies exceeding 10**19 eV, to identify the particle type(s), and to investigate the interactions of those cosmic particles both in space and in themore » Earth's atmosphere. The Pierre Auger Observatory in Argentina was completed in June 2008 with 1660 surface detector stations and 24 fluorescence telescopes arranged in 4 stations. It has a collecting area of 3,000 square km, yielding an aperture of 7,000 km**2 sr.« less

Influence of ICRF heating on the stability of TAEs

NASA Astrophysics Data System (ADS)

Sears, J.; Burke, W.; Parker, R. R.; Snipes, J. A.; Wolfe, S.

2007-11-01

Unstable toroidicity-induced Alfv'en eigenmodes (TAEs) can appear spontaneously due to resonant interaction with fast particles such as fusion alphas, raising concern that TAEs may threaten ITER performance. This work investigates the progression of stable TAE damping rates toward instability during a scan of ICRF heating power up to 3.1 MW. Stable eigenmodes are identified in Alcator C-Mod by the Active MHD diagnostic. Unstable TAEs are observed to appear spontaneously in C-Mod limited L-mode plasmas at sufficient tail energies generated by >3 MW of ICRF heating. However preliminary analysis of experiments with moderate ICRF heating power show that TAE stability may not simply degrade with overall fast particle content. There are hints that the stability of some TAEs may be enhanced in the presence of fast particle distribution tails. Furthermore, the radial profile of the energetic particle distribution relative to the safety factor profile affects the ICRF power influence on TAE stability.

SR-BI Selective Lipid Uptake: Subsequent Metabolism of Acute Phase HDL

PubMed Central

de Beer, Maria C.; Webb, Nancy R.; Whitaker, Nathan L.; Wroblewski, Joanne M.; Jahangiri, Anisa; van der Westhuyzen, Deneys R.; de Beer, Frederick C.

2009-01-01

Objective To investigate the interaction of SAA and SR-BI in remodeling of acute phase HDL (AP HDL). Methods and Results We used SAA and SR-BI adenoviral vector expression models to study the interaction between these entities. SR-BI processing of mouse AP HDL generated progressively smaller discreet HDL particles with distinct apolipoprotein compositions. SR-BI actions segregated apolipoproteins with the smallest particles containing only apoA-I. Larger remnants contained apoA-I, apoA-II and SAA. Small apoA-I only particles failed to associate with preformed HDL whereas larger remnants readily did. The presence of SAA on SR-BI processed HDL particles propelled apoA-I to a small lipid-poor form and accelerated apoA-I catabolism. Conclusions Data indicate that after core and surface HDL lipid perturbation by SR-BI, SAA propels apoA-I to a small lipid-poor form while accelerating HDL metabolism. PMID:19304574

A purely Lagrangian method for simulating the shallow water equations on a sphere using smooth particle hydrodynamics

NASA Astrophysics Data System (ADS)

Capecelatro, Jesse

2018-03-01

It has long been suggested that a purely Lagrangian solution to global-scale atmospheric/oceanic flows can potentially outperform tradition Eulerian schemes. Meanwhile, a demonstration of a scalable and practical framework remains elusive. Motivated by recent progress in particle-based methods when applied to convection dominated flows, this work presents a fully Lagrangian method for solving the inviscid shallow water equations on a rotating sphere in a smooth particle hydrodynamics framework. To avoid singularities at the poles, the governing equations are solved in Cartesian coordinates, augmented with a Lagrange multiplier to ensure that fluid particles are constrained to the surface of the sphere. An underlying grid in spherical coordinates is used to facilitate efficient neighbor detection and parallelization. The method is applied to a suite of canonical test cases, and conservation, accuracy, and parallel performance are assessed.

Applications of Micro/Nanoparticles in Microfluidic Sensors: A Review

PubMed Central

Jiang, Yusheng; Wang, Hui; Li, Shunbo; Wen, Weijia

2014-01-01

This paper reviews the applications of micro/nanoparticles in microfluidics device fabrication and analytical processing. In general, researchers have focused on two properties of particles—electric behavior and magnetic behavior. The applications of micro/nanoparticles could be summarized on the chip fabrication level and on the processing level. In the fabrication of microfluidic chips (chip fabrication level), particles are good additives in polydimethylsiloxane (PDMS) to prepare conductive or magnetic composites which have wide applications in sensors, valves and actuators. On the other hand, particles could be manipulated according to their electric and magnetic properties under external electric and magnetic fields when they are travelling in microchannels (processing level). Researchers have made a great progress in preparing modified PDMS and investigating the behaviors of particles in microchannels. This article attempts to present a discussion on the basis of particles applications in microfluidics. PMID:24755517

Physical Explanation of Archie's Porosity Exponent in Granular Materials: A Process-Based, Pore-Scale Numerical Study

NASA Astrophysics Data System (ADS)

Niu, Qifei; Zhang, Chi

2018-02-01

The empirical Archie's law has been widely used in geosciences and engineering to explain the measured electrical resistivity of many geological materials, but its physical basis has not been fully understood yet. In this study, we use a pore-scale numerical approach combining discrete element-finite difference methods to study Archie's porosity exponent m of granular materials over a wide porosity range. Numerical results reveal that at dilute states (e.g., porosity ϕ > 65%), m is exclusively related to the particle shape and orientation. As the porosity decreases, the electric flow in pore space concentrates progressively near particle contacts and m increases continuously in response to the intensified nonuniformity of the local electrical field. It is also found that the increase in m is universally correlated with the volume fraction of pore throats for all the samples regardless of their particle shapes, particle size range, and porosities.

Streaming and particle motion in acoustically-actuated leaky systems

NASA Astrophysics Data System (ADS)

Nama, Nitesh; Barnkob, Rune; Jun Huang, Tony; Kahler, Christian; Costanzo, Francesco

2017-11-01

The integration of acoustics with microfluidics has shown great promise for applications within biology, chemistry, and medicine. A commonly employed system to achieve this integration consists of a fluid-filled, polymer-walled microchannel that is acoustically actuated via standing surface acoustic waves. However, despite significant experimental advancements, the precise physical understanding of such systems remains a work in progress. In this work, we investigate the nature of acoustic fields that are setup inside the microchannel as well as the fundamental driving mechanism governing the fluid and particle motion in these systems. We provide an experimental benchmark using state-of-art 3D measurements of fluid and particle motion and present a Lagrangian velocity based temporal multiscale numerical framework to explain the experimental observations. Following verification and validation, we employ our numerical model to reveal the presence of a pseudo-standing acoustic wave that drives the acoustic streaming and particle motion in these systems.

Utilization of microparticles in next-generation assays for microflow cytometers.

PubMed

Kim, Jason S; Ligler, Frances S

2010-11-01

Micron-sized particles have primarily been used in microfabricated flow cytometers for calibration purposes and proof-of-concept experiments. With increasing frequency, microparticles are serving as a platform for assays measured in these small analytical devices. Light scattering has been used to measure the agglomeration of antibody-coated particles in the presence of an antigen. Impedance detection is another technology being integrated into microflow cytometers for microparticle-based assays. Fluorescence is the most popular detection method in flow cytometry, enabling highly sensitive multiplexed assays. Finally, magnetic particles have also been used to measure antigen levels using a magnetophoretic micro-device. We review the progress of microparticle-based assays in microflow cytometry in terms of the advantages and limitations of each approach.

Nuclear and particle physics, astrophysics and cosmology (NPAC) capability review

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

Redondo, Antonio

2010-01-01

The present document represents a summary self-assessment of the status of the Nuclear and Particle Physics, Astrophysics and Cosmology (NPAC) capability across Los Alamos National Laboratory (LANL). For the purpose of this review, we have divided the capability into four theme areas: Nuclear Physics, Particle Physics, Astrophysics and Cosmology, and Applied Physics. For each theme area we have given a general but brief description of the activities under the area, a list of the Laboratory divisions involved in the work, connections to the goals and mission of the Laboratory, a brief description of progress over the last three years, ourmore » opinion of the overall status of the theme area, and challenges and issues.« less

Progress report on hot particle studies

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

Baum, J.W.; Kaurin, D.G.; Waligorski, M.

1992-02-01

NCRP Report 106 on the effects of hot particles on the skin of pigs, monkeys, and humans was critically reviewed and reassessed. The analysis of the data of Forbes and Mikhail on the effects from activated UC{sub 2} particles, ranging in diameter from 144 {mu}m to 328 {mu}m, led to the formulation of a new model to predict both the threshold for acute ulceration and for ulcer diameter. In this model, a point dose of 27 Gy at a depth of 1.33 mm in tissue will cause an ulcer with a diameter determined by the radius to which this dosemore » extends. Application of the model to the Forbes and Mikhail data obtained with mixed fission product beta particles yielded a threshold'' (5% probability) of 6 {times} 10{sup 9} beta particles from a point source of high energy (2.25 MeV maximum) beta particles on skin. The above model was used to predict that approximately 1.2 {times} 10{sup 10} beta particles from Sr-Y-90 would produce similar effects, since few Sr-90 beta particles reach 1.33 mm depth. These emissions correspond to doses at 70-{mu}m depth in tissue of approximately 5.3 to 5.5 Gy averaged over 1 cm{sup 2}, respectively.« less

Progress report on hot particle studies

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

Baum, J.W.; Kaurin, D.G.; Waligorski, M.

1992-02-01

NCRP Report 106 on the effects of hot particles on the skin of pigs, monkeys, and humans was critically reviewed and reassessed. The analysis of the data of Forbes and Mikhail on the effects from activated UC{sub 2} particles, ranging in diameter from 144 {mu}m to 328 {mu}m, led to the formulation of a new model to predict both the threshold for acute ulceration and for ulcer diameter. In this model, a point dose of 27 Gy at a depth of 1.33 mm in tissue will cause an ulcer with a diameter determined by the radius to which this dosemore » extends. Application of the model to the Forbes and Mikhail data obtained with mixed fission product beta particles yielded a ``threshold`` (5% probability) of 6 {times} 10{sup 9} beta particles from a point source of high energy (2.25 MeV maximum) beta particles on skin. The above model was used to predict that approximately 1.2 {times} 10{sup 10} beta particles from Sr-Y-90 would produce similar effects, since few Sr-90 beta particles reach 1.33 mm depth. These emissions correspond to doses at 70-{mu}m depth in tissue of approximately 5.3 to 5.5 Gy averaged over 1 cm{sup 2}, respectively.« less

Recent progress in the microscopic description of small and large amplitude collective motion

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

Lacroix, D., E-mail: lacroix@ipno.in2p3.fr; Tanimura, Y.; Ayik, S.

2015-10-15

Dynamical mean-field theory has recently attracted much interests to provide a unified framework for the description of many aspects of nuclear dynamics [1, 2, 3, 4, 5] (for recent reviews see [6, 7]). In particular, the inclusion of pairing correlation has opened new perspectives [8, 9, 10, 11, 12]. A summary of recent applications including giant resonances and transfer reactions will be made in this talk [13, 14, 15, 16]. While new progresses have been made with the use of sophisticated effective interactions and the development of symmetry unrestricted applications, mean-field dynamics suffer from the poor treatment of quantum fluctuationsmore » in collective space. As a consequence, these theories are successful in describing average properties of many different experimental observations but generally fail to account realistically for the width of experimental distribution. The increase of predictive power of dynamical mean-field theory is facing the difficulty of going beyond the independent particle or quasi-particle picture. Nevertheless, in the last decade, novel methods have been proposed to prepare the next generation of microscopic mean-field codes able to account for both average properties and fluctuations around the average. A review of recent progresses in this direction as well as recent applications to heavy-ion collisions will be given [17, 18].« less

Rheology of granular materials composed of crushable particles.

PubMed

Nguyen, Duc-Hanh; Azéma, Émilien; Sornay, Philippe; Radjaï, Farhang

2018-04-11

We investigate sheared granular materials composed of crushable particles by means of contact dynamics simulations and the bonded-cell model for particle breakage. Each particle is paved by irregular cells interacting via cohesive forces. In each simulation, the ratio of the internal cohesion of particles to the confining pressure, the relative cohesion, is kept constant and the packing is subjected to biaxial shearing. The particles can break into two or more fragments when the internal cohesive forces are overcome by the action of compressive force chains between particles. The particle size distribution evolves during shear as the particles continue to break. We find that the breakage process is highly inhomogeneous both in the fragment sizes and their locations inside the packing. In particular, a number of large particles never break whereas a large number of particles are fully shattered. As a result, the packing keeps the memory of its initial particle size distribution, whereas a power-law distribution is observed for particles of intermediate size due to consecutive fragmentation events whereby the memory of the initial state is lost. Due to growing polydispersity, dense shear bands are formed inside the packings and the usual dilatant behavior is reduced or cancelled. Hence, the stress-strain curve no longer passes through a peak stress, and a progressive monotonic evolution towards a pseudo-steady state is observed instead. We find that the crushing rate is controlled by the confining pressure. We also show that the shear strength of the packing is well expressed in terms of contact anisotropies and force anisotropies. The force anisotropy increases while the contact orientation anisotropy declines for increasing internal cohesion of the particles. These two effects compensate each other so that the shear strength is nearly independent of the internal cohesion of particles.

MODE OF INHERITANCE IN SUSCEPTIBILITY TO INHALED ACID-COATED PARTICLES IN MICE. (R825815)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

AGE-RELATED RESPONSES IN RATS TO CONCENTRATED URBAN AIR PARTICLES (CAPS). (R825242)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

AIRBORNE FINE AND ULTRAFINE PARTICLES NEAR THE WORLD TRADE CENTER DISASTER SITE. (R827351)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

ASSOCIATION OF PERSONAL PARTICLE EXPOSURE WITH HEART RATE VARIABILITY. (R828678C002)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

LAGRANGIAN PARTICLE DISPERSION MODELING OF THE FUMIGATION PROCESS USING LARGE-EDDY SIMULATION. (R828178)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

EXTRAPULMONARY TRANSLOCATION OF ULTRAFINE CARBON PARTICLES FOLLOWING INHALATION EXPOSURE. (R827354C004)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

EFFECT OF SURFACE HYDROPHOBICITY ON THE HYDRODYNAMIC DETACHMENT OF PARTICLES FROM SURFACES (R821268)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

INTERACTIONS BETWEEN INHALED ULTRAFINE PARTICLES AND SYSTEMIC ENDOTOXIN IN TWO RAT STRAINS. (R826784)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

COMPOSITION OF INHALED URBAN AIR PARTICLES DETERMINES ACUTE PULMONARY RESPONSES. (R827353C008)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Design colloidal particle morphology and self-assembly for coating applications

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

Jiang, Shan; Van Dyk, Antony; Maurice, Alvin

The progressive replacement of organic solvent-based coatings by waterborne latex polymer coatings has substantially renovated the coating industry, and generated huge environmental and health benefits. Today, on top of the continuing demand for higher performance and lower costs, the coating industry faces tighter regulation and higher sustainability standards. In addition, the new waterborne coatings have created unique opportunities and challenges in terms of fundamental understanding and research development. To address these challenges, polymer latex binders with diverse particle morphologies have been developed to improve coating performance. Furthermore, colloidal self-assembly has been utilized to help manufacturers make better paint with lessmore » cost. In this report, we review the recent progress in both fundamental study and industrial application in the context of developing new generation architectural coating materials. We introduce the basic concepts in coating materials and showcase several key technologies that have been implemented to improve coating performance. As a result, these technologies also represent the most important considerations in architectural coating design.« less

Large eddy simulation of piloted pulverised coal combustion using extended flamelet/progress variable model

NASA Astrophysics Data System (ADS)

Wen, Xu; Luo, Kun; Jin, Hanhui; Fan, Jianren

2017-09-01

An extended flamelet/progress variable (EFPV) model for simulating pulverised coal combustion (PCC) in the context of large eddy simulation (LES) is proposed, in which devolatilisation, char surface reaction and radiation are all taken into account. The pulverised coal particles are tracked in the Lagrangian framework with various sub-models and the sub-grid scale (SGS) effects of turbulent velocity and scalar fluctuations on the coal particles are modelled by the velocity-scalar joint filtered density function (VSJFDF) model. The presented model is then evaluated by LES of an experimental piloted coal jet flame and comparing the numerical results with the experimental data and the results from the eddy break up (EBU) model. Detailed quantitative comparisons are carried out. It is found that the proposed model performs much better than the EBU model on radial velocity and species concentrations predictions. Comparing against the adiabatic counterpart, we find that the predicted temperature is evidently lowered and agrees well with the experimental data if the conditional sampling method is adopted.

Design colloidal particle morphology and self-assembly for coating applications

DOE PAGES

Jiang, Shan; Van Dyk, Antony; Maurice, Alvin; ...

2017-05-04

The progressive replacement of organic solvent-based coatings by waterborne latex polymer coatings has substantially renovated the coating industry, and generated huge environmental and health benefits. Today, on top of the continuing demand for higher performance and lower costs, the coating industry faces tighter regulation and higher sustainability standards. In addition, the new waterborne coatings have created unique opportunities and challenges in terms of fundamental understanding and research development. To address these challenges, polymer latex binders with diverse particle morphologies have been developed to improve coating performance. Furthermore, colloidal self-assembly has been utilized to help manufacturers make better paint with lessmore » cost. In this report, we review the recent progress in both fundamental study and industrial application in the context of developing new generation architectural coating materials. We introduce the basic concepts in coating materials and showcase several key technologies that have been implemented to improve coating performance. As a result, these technologies also represent the most important considerations in architectural coating design.« less

Status and path to a final EUVL reticle-handling solution

NASA Astrophysics Data System (ADS)

He, Long; Orvek, Kevin; Seidel, Phil; Wurm, Stefan; Underwood, Jon; Betancourt, Ernie

2007-03-01

In extreme ultraviolet lithography (EUVL), the lack of a suitable material to build conventional pellicles calls for industry standardization of new techniques for protection and handling throughout the reticle's lifetime. This includes reticle shipping, robotic handling, in-fab transport, storage, and uses in atmospheric environments for metrology and vacuum environments for EUV exposure. In this paper, we review the status of the industry-wide progress in developing EUVL reticle-handling solutions. We show the industry's leading reticle carrier approaches for particle-free protection, such as improvements in conventional single carrier designs and new EUVL-specific carrier concepts, including variations on a removable pellicle. Our test indicates dual pod approach of the removable pellicle led to nearly particle-free use during a simulated life cycle, at ~50nm inspection sensitivity. We will provide an assessment of the remaining technical challenges facing EUVL reticle-handling technology. Finally, we will review the progress of the SEMI EUVL Reticle-handling Task Force in its efforts to standardize a final EUV reticle protection and handling solution.

Shape of wear particles found in human knee joints and their relationship to osteoarthritis.

PubMed

Kuster, M S; Podsiadlo, P; Stachowiak, G W

1998-09-01

To analyse and compare the shape of wear particles found in healthy and osteoarthritic human knee joints for monitoring the progress of osteoarthritis, the long-term prognosis and to evaluate therapeutic regimens. Joint particles from seven patients with normal cartilage in all compartments of the knee joint, 12 patients with fibrillation of less than half the cartilage thickness (grade 1), seven patients with fibrillation of more than half the cartilage thickness (grade 2) and four patients with erosions down to bone (grade 3) were analysed. A total of 565 particles were extracted from synovial fluid samples by ferrography and analysed in a scanning electron microscope. A number of numerical descriptors, i.e. boundary fractal dimension, shape factor, convexity and elongation, were calculated for each particle image and correlated to the degree of osteoarthritis using non-parametric tests. Experiments demonstrated that there were significant differences between the numerical descriptors calculated for wear particles from healthy and osteoarthritic knee joints (P < 0.01), suggesting that the particle shape can be used as an indicator of the joint condition. In particular, the fractal dimension of the particle boundary was shown to correlate directly with the degree of osteoarthritis. Numerical analysis of the shape of wear particles found in human knee joints may provide a reliable means for the assessment of cartilage repair after surgical or conservative treatment of osteoarthritis.

Viral nerve necrosis in hatchery-produced fry of Asian seabass Lates calcarifer: sequential microscopic analysis of histopathology.

PubMed

Azad, I S; Shekhar, M S; Thirunavukkarasu, A R; Jithendran, K P

2006-12-14

We studied the natural progression of viral nerve necrosis (VNN) in larvae of Asian seabass Lates calcarifer Bloch from 0 to 40 days post-hatch (dph). The hatchlings were reared in the vicinity of a confirmed nodavirus-affected older batch. Using light and electron microscopy (EM), we made a sequential analysis of histopathological manifestations in nerve tissue and other organs. There were no changes from the day of hatching until 4 dph. Larvae at 4 dph had viral particles in the intramuscular spaces underlying the skin, but the nerve cells of the brain were normal. The first signs of necrosis of the brain cells were observed at 6 dph. EM observations revealed characteristic membrane-bound viral particles measuring 30 nm in the cytoplasm of nerve cells of the brain, spinal cord and retina. Histological samples of fry examined when group mortalities reached 20 to 35% revealed highly vacuolated brains, empty nerve cell cytoplasm and viral particles in the intercellular spaces. Viral particles occurred extensively in the intramuscular spaces and the epidermal layers. These observations were corroborated by positive immunostaining of the virus-rich intramuscular spaces. EM studies also revealed progressive necrotic changes in the cells harboring the virus. Results emphasize the need to maintain hygiene in the hatchery environment and to develop strategies for prevention of disease spread among cohabiting seabass and other susceptible fish larvae. Intramuscular localization of the nodavirus in both preclinical healthy-looking and post-clinical moribund larvae suggests that virus neutralization strategies during larval development could be effective in controlling VNN-associated mortalities.

Debilitating lung disease among surface coal miners with no underground mining tenure.

PubMed

Halldin, Cara N; Reed, William R; Joy, Gerald J; Colinet, Jay F; Rider, James P; Petsonk, Edward L; Abraham, Jerrold L; Wolfe, Anita L; Storey, Eileen; Laney, A Scott

2015-01-01

To characterize exposure histories and respiratory disease among surface coal miners identified with progressive massive fibrosis from a 2010 to 2011 pneumoconiosis survey. Job history, tenure, and radiograph interpretations were verified. Previous radiographs were reviewed when available. Telephone follow-up sought additional work and medical history information. Among eight miners who worked as drill operators or blasters for most of their tenure (median, 35.5 years), two reported poor dust control practices, working in visible dust clouds as recently as 2012. Chest radiographs progressed to progressive massive fibrosis in as few as 11 years. One miner's lung biopsy demonstrated fibrosis and interstitial accumulation of macrophages containing abundant silica, aluminum silicate, and titanium dust particles. Overexposure to respirable silica resulted in progressive massive fibrosis among current surface coal miners with no underground mining tenure. Inadequate dust control during drilling/blasting is likely an important etiologic factor.

Debilitating Lung Disease Among Surface Coal Miners With No Underground Mining Tenure

PubMed Central

Halldin, Cara N.; Reed, William R.; Joy, Gerald J.; Colinet, Jay F.; Rider, James P.; Petsonk, Edward L.; Abraham, Jerrold L.; Wolfe, Anita L.; Storey, Eileen; Laney, A. Scott

2015-01-01

Objective To characterize exposure histories and respiratory disease among surface coal miners identified with progressive massive fibrosis from a 2010 to 2011 pneumoconiosis survey. Methods Job history, tenure, and radiograph interpretations were verified. Previous radiographs were reviewed when available. Telephone follow-up sought additional work and medical history information. Results Among eight miners who worked as drill operators or blasters for most of their tenure (median, 35.5 years), two reported poor dust control practices, working in visible dust clouds as recently as 2012. Chest radiographs progressed to progressive massive fibrosis in as few as 11 years. One miner’s lung biopsy demonstrated fibrosis and interstitial accumulation of macrophages containing abundant silica, aluminum silicate, and titanium dust particles. Conclusions Overexposure to respirable silica resulted in progressive massive fibrosis among current surface coal miners with no underground mining tenure. Inadequate dust control during drilling/blasting is likely an important etiologic factor. PMID:25563541

LIPOPOLYSACCHARIDE PRIMING AMPLIFIES LUNG MACROPHAGE TUMOR NECROSIS FACTOR PRODUCTION IN RESPONSE TO AIR PARTICLES. (R824790)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

A Study of Particle Acceleration Mechanisms and the Dynamics of the Outer Trapping Region by Observations at Synchronous Orbit: a Summary of Scientific Results

NASA Technical Reports Server (NTRS)

Erickson, K. N.

1980-01-01

The research concerning the ATS-6 synchronous orbit satellite is reported. The completed research and results are discussed along with the research in progress. Abstracts of published papers are included.

RESPIRATORY DISEASE AS A CONTRIBUTING CAUSE OF NON-RESPIRATORY MORTALITY ASSOCIATIONS WITH PARTICLE MASS. (R825271)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Application of Ferrofluids as an Acoustic Transducer Material.

DTIC Science & Technology

1979-12-04

oleic acid . The carrier is typically nonconductive, but efforts are in progress to suspend the particles in conducting liquids such as mercury or...and at lower temperature in high-vacuum applications. It has excellent chemical stability to 120*C. The carrier is bis- (2 ethylhexyl) azelate which

INHALATION OF CONCENTRATED AMBIENT AIR PARTICLES EXACERBATES MYOCARDIAL ISCHEMIA IN CONSCIOUS DOGS. (R827353C008)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

GENOME-WIDE EXPRESSION MONITORING IN RATS EXPOSED TO PARTICLES AND OZONE. (R827351C005)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

EXTRAPULMONARY TRANSLOCATION OF ULTRAFINE CARBON PARTICLES FOLLOWING WHOLE-BODY INHALATION EXPOSURE OF RATS. (R826784)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

ALTERATION IN LUNG PARTICLE TRANSLOCATION, MACROPHAGE FUNCTION, AND MICROFILAMENT ARRANGEMENT IN MONOCROTALINE-TREATED RATS. (R826246)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

AGE ALTERS MACROPHAGE RESPONSES TO ENDOTOXIN AND PARTICLE-INDUCED CYTOKINE GENE EXPRESSION. (R827354C005)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

ALVEOLAR MACROPHAGE CYTOKINE PRODUCTION IN RESPONSE TO AIR PARTICLES IN VITRO: ROLE OF ENDOTOXIN. (R824790)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

VISIBILITY AS A SURROGATE FOR PARTICLE POLLUTION IN MULTI-CENTER POPULATION-BASED STUDIES. (R827994)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

MOLECULAR DYNAMICS STUDY OF SILVER PARTICLES FOR LOW TEMPERATURE LEAD FREE INTERCONNECT APPLICATIONS. (R831489)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

A METHODOLOGY FOR MEASURING SIZE-DEPENDENT CHEMICAL COMPOSITION OF ULTRAFINE PARTICLES. (R828678C009)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

FINE AMBIENT AIR PARTICULAR MATTER EXPOSURE INDUCES MOLECULAR ALTERATIONS INDICATIVE OF CARDIOVASCULAR DISEASE PROGRESSION IN ATHEROSCLEROTIC SUSCEPTIBLE MICE

EPA Science Inventory

Epidemiological, clinical, and toxicological studies have demonstrated that exposure to ambient air particulate matter (PM) can alter cardiovascular function and may influence cardiovascular disease (CVD). It has been shown that exposure to concentrated ambient air particles (CA...

SINGLE PARTICLE CHARACTERIZATION OF AUTOMOBILE AND DIESEL TRUCK EMISSIONS IN THE CALDECOTT TUNNEL. (U915566)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Chalk-Ex: Transport of Optically Active Particles from the Surface Mixed Layer

DTIC Science & Technology

2002-09-30

and K. A. Kilpatrick. 1998. Scattering and attenuation properties of Emiliania huxleyi cells and their detached coccoliths. Limnol. Oceanogr. 43...coccolithophore Emiliania huxleyi under steady-state light-limited growth. Marine Ecology Progress Series. 142: 87-97. Bidigare, R. R. , M. Latasa, Z

InGaP alpha voltaic batteries: Synthesis, modeling, and radiation tolerance

NASA Astrophysics Data System (ADS)

Cress, Cory D.; Landi, Brian J.; Raffaelle, Ryne P.; Wilt, David M.

2006-12-01

The viability of InGaP diodes coupled with α-particle sources as radioisotope power supplies is investigated both theoretically and experimentally. The electrical power output of epitaxially grown InGaP p-type/n-type (p/n) junction diodes coupled with Am241 and Po210 α-particle sources was measured. A theoretical model was developed that determines the α-particle energy deposition profile within an InGaP diode when irradiated by an omnidirectional α-particle source. The results of the model illustrate the dramatic influence the radiation source/diode configuration has on the α-particle energy deposition profile within a device. Progress has been shown towards increasing the radiation tolerance of the InGaP devices, which included utilizing an intrinsic region and reducing the junction thickness. Introduction of the intrinsic region within a conventional n /p diode to form a n-type/intrinsic/p-type diode enabled the device to withstand a ten times greater fluence of 4.2MeV α particles before decreasing to 50% of its original power output under simulated air mass zero illumination, when compared to an abrupt junction device with the same active region thickness.

Machine remaining useful life prediction: An integrated adaptive neuro-fuzzy and high-order particle filtering approach

NASA Astrophysics Data System (ADS)

Chen, Chaochao; Vachtsevanos, George; Orchard, Marcos E.

2012-04-01

Machine prognosis can be considered as the generation of long-term predictions that describe the evolution in time of a fault indicator, with the purpose of estimating the remaining useful life (RUL) of a failing component/subsystem so that timely maintenance can be performed to avoid catastrophic failures. This paper proposes an integrated RUL prediction method using adaptive neuro-fuzzy inference systems (ANFIS) and high-order particle filtering, which forecasts the time evolution of the fault indicator and estimates the probability density function (pdf) of RUL. The ANFIS is trained and integrated in a high-order particle filter as a model describing the fault progression. The high-order particle filter is used to estimate the current state and carry out p-step-ahead predictions via a set of particles. These predictions are used to estimate the RUL pdf. The performance of the proposed method is evaluated via the real-world data from a seeded fault test for a UH-60 helicopter planetary gear plate. The results demonstrate that it outperforms both the conventional ANFIS predictor and the particle-filter-based predictor where the fault growth model is a first-order model that is trained via the ANFIS.

Direct observation and analysis of york-shell materials using low-voltage high-resolution scanning electron microscopy: Nanometal-particles encapsulated in metal-oxide, carbon, and polymer

NASA Astrophysics Data System (ADS)

Asahina, Shunsuke; Suga, Mitsuo; Takahashi, Hideyuki; Young Jeong, Hu; Galeano, Carolina; Schüth, Ferdi; Terasaki, Osamu

2014-11-01

Nanometal particles show characteristic features in chemical and physical properties depending on their sizes and shapes. For keeping and further enhancing their features, the particles should be protected from coalescence or degradation. One approach is to encapsulate the nanometal particles inside pores with chemically inert or functional materials, such as carbon, polymer, and metal oxides, which contain mesopores to allow permeation of only chemicals not the nanometal particles. Recently developed low-voltage high-resolution scanning electron microscopy was applied to the study of structural, chemical, and electron state of both nanometal particles and encapsulating materials in yolk-shell materials of Au@C, Ru/Pt@C, Au@TiO2, and Pt@Polymer. Progresses in the following categories were shown for the yolk-shell materials: (i) resolution of topographic image contrast by secondary electrons, of atomic-number contrast by back-scattered electrons, and of elemental mapping by X-ray energy dispersive spectroscopy; (ii) sample preparation for observing internal structures; and (iii) X-ray spectroscopy such as soft X-ray emission spectroscopy. Transmission electron microscopy was also used for characterization of Au@C.

Design and process aspects of laboratory scale SCF particle formation systems.

PubMed

Vemavarapu, Chandra; Mollan, Matthew J; Lodaya, Mayur; Needham, Thomas E

2005-03-23

Consistent production of solid drug materials of desired particle and crystallographic morphologies under cGMP conditions is a frequent challenge to pharmaceutical researchers. Supercritical fluid (SCF) technology gained significant attention in pharmaceutical research by not only showing a promise in this regard but also accommodating the principles of green chemistry. Given that this technology attained commercialization in coffee decaffeination and in the extraction of hops and other essential oils, a majority of the off-the-shelf SCF instrumentation is designed for extraction purposes. Only a selective few vendors appear to be in the early stages of manufacturing equipment designed for particle formation. The scarcity of information on the design and process engineering of laboratory scale equipment is recognized as a significant shortcoming to the technological progress. The purpose of this article is therefore to provide the information and resources necessary for startup research involving particle formation using supercritical fluids. The various stages of particle formation by supercritical fluid processing can be broadly classified into delivery, reaction, pre-expansion, expansion and collection. The importance of each of these processes in tailoring the particle morphology is discussed in this article along with presenting various alternatives to perform these operations.

In Situ Single Particle Measurement of Atmospheric Aging of Carbonaceous Aerosols During CARES

NASA Astrophysics Data System (ADS)

Cahill, J. F.; Suski, K.; Hubbe, J.; Shilling, J.; Zaveri, R. A.; Springston, S. R.; Prather, K. A.

2011-12-01

Atmospheric aging of aerosols through photochemistry, heterogeneous reactions and aqueous processing can change their physical and chemical properties, impacting their gas uptake, radiative forcing, and activation of cloud nuclei. Understanding the timescale and magnitude of this aging process is essential for accurate aerosol-climate modeling and predictions. An aircraft aerosol time-of-flight mass spectrometer (A-ATOFMS) measured single particle mixing state during the Carbonaceous Aerosols and Radiative Effects Study (CARES) in the summer of 2010 over Sacramento, CA. On 6/23/10, flights in the morning and afternoon performed pseudo-Lagrangian sampling of the Sacramento urban plume. Carbonaceous particles from these flights were classified into 'aged' and 'fresh' classes based on their mixing state, with aged particles having more secondary species, such as nitrate and sulfate. In the morning flight, a clear decreasing trend in the ratio of fresh/aged particle types was seen as the flight progressed, whereas in the afternoon flight, the ratio was essentially constant. These data show that in the morning carbonaceous aerosols can become heavily oxidized in a few hours. Further analysis of particle mixing state and the timescale of carbonaceous aerosol aging will be presented

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

Syphers, M. J.; Chattopadhyay, S.

An overview is provided of the currently envisaged landscape of charged particle accelerators at the energy and intensity frontiers to explore particle physics beyond the standard model via 1-100 TeV-scale lepton and hadron colliders and multi-Megawatt proton accelerators for short- and long- baseline neutrino experiments. The particle beam physics, associated technological challenges and progress to date for these accelerator facilities (LHC, HL-LHC, future 100 TeV p-p colliders, Tev-scale linear and circular electron-positron colliders, high intensity proton accelerator complex PIP-II for DUNE and future upgrade to PIP-III) are outlined. Potential and prospects for advanced “nonlinear dynamic techniques” at the multi-MW levelmore » intensity frontier and advanced “plasma- wakefield-based techniques” at the TeV-scale energy frontier and are also described.« less

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

Martin, Christopher Blake

A new particle decaying to a pair of vector bosons was discovered in 2012 by the ATLAS and CMS experiments at the Large Hadron Collider. In the wake of this discovery a rush of measurements was made to characterize this particle. The fourlepton final state has been instrumental in both the discovery and characterization of this new particle. With only about 20 events seen in the resonance peak at 125 GeV the CMS experiment has been able to make considerable progress in characterizing the Higgs-like boson using the wealth of information in this final state in concert with other decaymore » modes. In addition to the search for this new boson we present three recent results in the study of the Higgs-like boson properties: studies of the production mode, total width, and spin-parity quantum numbers.« less

Direct writing of metal nanostructures: lithographic tools for nanoplasmonics research.

PubMed

Leggett, Graham J

2011-03-22

Continued progress in the fast-growing field of nanoplasmonics will require the development of new methods for the fabrication of metal nanostructures. Optical lithography provides a continually expanding tool box. Two-photon processes, as demonstrated by Shukla et al. (doi: 10.1021/nn103015g), enable the fabrication of gold nanostructures encapsulated in dielectric material in a simple, direct process and offer the prospect of three-dimensional fabrication. At higher resolution, scanning probe techniques enable nanoparticle particle placement by localized oxidation, and near-field sintering of nanoparticulate films enables direct writing of nanowires. Direct laser "printing" of single gold nanoparticles offers a remarkable capability for the controlled fabrication of model structures for fundamental studies, particle-by-particle. Optical methods continue to provide a powerful support for research into metamaterials.

Second-order Compton-Getting effect on arbitrary intensity distribution

NASA Technical Reports Server (NTRS)

Ng, C. K.

1985-01-01

Theoretical studies of energetic particles in space are often referred to a special frame of reference. To compare theory with experiment, one has to transform the particle distribution from the special frame to the observer's frame, or vice versa. Various methods have been derived to obtain the directional distribution in the comoving frame from the directional fluxes measured on a spacecraft. These methods have become progressively complicated as increasingly detailed directional particle data become available. A set of 2nd order correct formulae for the transformation of an arbitrary differential intensity distribution, expressed as a series of spherical harmonics, between any two frames in constant relative motion is presented. These formulae greatly simplify the complicated procedures currently in use for the determination of the differential intensity distribution in a comoving frame.

Radiation reaction force on a particle in Schwarzschild spacetime

NASA Astrophysics Data System (ADS)

Tripathi, Swapnil; Wiseman, Alan

2007-04-01

The mathematical modelling of the radiation reaction force experienced by a particle in curved spacetime is very important for calculations of the templates used in detection of gravitational waves with LIGO, LISA etc. In particular, extreme mass ratio inspirals are strong candidates for gravitational wave detection with LISA. We model these systems as a particle in Schwarzschild spacetime, and use the Quinn Wald axioms to regularize the self force. Mode by mode expansion techniques are used for calculating the selfforce. Recent progress in this work is being reported in this talkootnotetextA. G. Wiseman, Phys. Rev. D 61 (2000) arXiv.org:gr-qc/084014 ootnotetextT.C. Quinn, Phys. Rev. D 62 (2000) arXiv.org:gr- qc/064029 ootnotetextT.C. Quinn, R.M. Wald Phys. Rev. D 56 (1997) 3381

Using science centers to expose the general public to the microworld

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

Malamud, E.

1994-08-01

Despite the remarkable progress in the past decades in understanding our Universe, we particle physicists have failed to communicate the wonder, excitement, and beauty of these discoveries to the general public. I am sure all agree there is a need, if our support from public funds is to continue at anywhere approximating the present level, for us collectively to educate and inform the general public of what we are doing and why. Informal science education and especially science and technology centers can play an important role in efforts to raise public awareness of particle physics in particular and of basicmore » research in general. Science Centers are a natural avenue for particle physicists to use to communicate with and gain support from the general public.« less

Aerosol reactor production of uniform submicron powders

NASA Technical Reports Server (NTRS)

Flagan, Richard C. (Inventor); Wu, Jin J. (Inventor)

1991-01-01

A method of producing submicron nonagglomerated particles in a single stage reactor includes introducing a reactant or mixture of reactants at one end while varying the temperature along the reactor to initiate reactions at a low rate. As homogeneously small numbers of seed particles generated in the initial section of the reactor progress through the reactor, the reaction is gradually accelerated through programmed increases in temperature along the length of the reactor to promote particle growth by chemical vapor deposition while minimizing agglomerate formation by maintaining a sufficiently low number concentration of particles in the reactor such that coagulation is inhibited within the residence time of particles in the reactor. The maximum temperature and minimum residence time is defined by a combination of temperature and residence time that is necessary to bring the reaction to completion. In one embodiment, electronic grade silane and high purity nitrogen are introduced into the reactor and temperatures of approximately 770.degree. K. to 1550.degree. K. are employed. In another embodiment silane and ammonia are employed at temperatures from 750.degree. K. to 1800.degree. K.

Aerosol reactor production of uniform submicron powders

DOEpatents

Flagan, Richard C.; Wu, Jin J.

1991-02-19

A method of producing submicron nonagglomerated particles in a single stage reactor includes introducing a reactant or mixture of reactants at one end while varying the temperature along the reactor to initiate reactions at a low rate. As homogeneously small numbers of seed particles generated in the initial section of the reactor progress through the reactor, the reaction is gradually accelerated through programmed increases in temperature along the length of the reactor to promote particle growth by chemical vapor deposition while minimizing agglomerate formation by maintaining a sufficiently low number concentration of particles in the reactor such that coagulation is inhibited within the residence time of particles in the reactor. The maximum temperature and minimum residence time is defined by a combination of temperature and residence time that is necessary to bring the reaction to completion. In one embodiment, electronic grade silane and high purity nitrogen are introduced into the reactor and temperatures of approximately 770.degree. K. to 1550.degree. K. are employed. In another embodiment silane and ammonia are employed at temperatures from 750.degree. K. to 1800.degree. K.

Quantitative characterization of the spatial distribution of particles in materials: Application to materials processing

NASA Technical Reports Server (NTRS)

Parse, Joseph B.; Wert, J. A.

1991-01-01

Inhomogeneities in the spatial distribution of second phase particles in engineering materials are known to affect certain mechanical properties. Progress in this area has been hampered by the lack of a convenient method for quantitative description of the spatial distribution of the second phase. This study intends to develop a broadly applicable method for the quantitative analysis and description of the spatial distribution of second phase particles. The method was designed to operate on a desktop computer. The Dirichlet tessellation technique (geometrical method for dividing an area containing an array of points into a set of polygons uniquely associated with the individual particles) was selected as the basis of an analysis technique implemented on a PC. This technique is being applied to the production of Al sheet by PM processing methods; vacuum hot pressing, forging, and rolling. The effect of varying hot working parameters on the spatial distribution of aluminum oxide particles in consolidated sheet is being studied. Changes in distributions of properties such as through-thickness near-neighbor distance correlate with hot-working reduction.

Interplanetary dust. [survey of last four years' research

NASA Technical Reports Server (NTRS)

Brownlee, D. E.

1979-01-01

Progress in the study of interplanetary dust during the past four years is reviewed. Attention is given to determinations of the relative contributions of interstellar dust grains, collisional debris from the asteroid belt and short-period comets to the interplanetary dust cloud. Effects of radiation pressure and collisions on particle dynamics are discussed, noting the discovery of the variation of the orbital parameters of dust particles at 1 AU with size and in situ measurements of dust density between 0.3 and 5 AU by the Helios and Pioneer spacecraft. The interpretation of the zodiacal light as produced by porous absorbing particles 10 to 100 microns in size is noted, and measurements of the Doppler shift, light-producing-particle density, UV spectrum, photometric axis and angular scattering function of the zodiacal light are reported. Results of analyses of lunar rock microcraters as to micrometeoroid density, flux rate, size distribution and composition are indicated and interplanetary dust particles collected from the stratosphere are discussed. Findings concerning the composition of fragile meteoroid types found as cosmic spherules in deep sea sediments are also presented.

Particle blender

DOEpatents

Willey, Melvin G.

1981-01-01

An infinite blender that achieves a homogeneous mixture of fuel microspheres is provided. Blending is accomplished by directing respective groups of desired particles onto the apex of a stationary coaxial cone. The particles progress downward over the cone surface and deposit in a space at the base of the cone that is described by a flexible band provided with a wide portion traversing and in continuous contact with the circumference of the cone base and extending upwardly therefrom. The band, being attached to the cone at a narrow inner end thereof, causes the cone to rotate on its arbor when the band is subsequently pulled onto a take-up spool. As a point at the end of the wide portion of the band passes the point where it is tangent to the cone, the blended particles are released into a delivery tube leading directly into a mold, and a plate mounted on the lower portion of the cone and positioned between the end of the wide portion of the band and the cone assures release of the particles only at the tangent point.

MACROSCOPIC AND MICROSCOPIC OBSERVATIONS OF PARTICLE-FACILITATED MERCURY TRANSPORT FROM NEW IDRIA AND SULPHUR BANK MERCURY MINE TAILINGS (R827634)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

PARTICLE-FACILITATED MERCURY TRANSPORT FROM NEW IDRIA AND SULPHUR BANK MERCURY MINE TAILINGS. 2. MICROSCOPIC AND SPECTROSCOPIC ANALYSIS. (R827634)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

FILTRATION OF RECOMBINANT NORWALK VIRUS PARTICLES AND BACTERIOPHAGE MS2 IN QUARTZ SAND: IMPORTANCE OF ELECTROSTATIC INTERACTIONS. (R824775)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

A HIGH VOLUME APPARATUS FOR THE CONDENSATIONAL GROWTH OF ULTRAFINE PARTICLES FOR INHALATION TOXICOLOGICAL STUDIES. (R825270)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Prospects for Physics in the 1990's Surveyed.

ERIC Educational Resources Information Center

Robinson, Arthur L.

1986-01-01

A National Academy of Science report ("Physics Through the 1990's") says that American physics has been a highly diversified and productive enterprise, but continued excellence cannot be taken for granted. Progress in six subfields (elementary particle, nuclear, condensed-matter, atomic/molecular, plasma/fluid, and gravitation/cosmology physics)…

HEMATOLOGIC RESPONSES TO INHALATION OF CONCENTRATED AIR PARTICLES (CAPS) AND TRANSIENT MYOCARDIAL ISCHEMIA (MI). (R827353C008)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

RESPIRATORY DISEASE AS A CONTRIBUTING CAUSE OF NON-RESPIRATORY MORTALITY ASSOCIATIONS WITH PARTICLE MASS IN NEW YORK CITY. (R825271)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

SIZE-FRACTIONATED MEASUREMENTS OF AMBIENT ULTRAFINE PARTICLE CHEMICAL COMPOSITION IN LOS ANGELES USING THE NANOMOUDI. (R827352C021)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

SOURCE APPORTIONMENT OF FINE PARTICULATE MATTER BY CLUSTERING SINGLE-PARTICLE DATA: TESTS OF RECEPTOR MODEL ACCURACY. (R826371C001)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

EFFECT OF INHALED ULTRAFINE CARBON PARTICLES ON THE ALLERGIC AIRWAY RESPONSE IN RAGWEED SENSITIZED DOGS. (R826442)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

DEVELOPMENT OF AN AEROSOL MASS SPECTROMETER FOR SIZE AND COMPOSITION ANALYSIS OF SUBMICRON PARTICLES. (R825253,R825391)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Physics in One Dimension

ERIC Educational Resources Information Center

Bertel, Erminald

2013-01-01

Due to progress in nanotechnology high-quality quantum wires can nowadays be fabricated. The behavior of particles in one dimension differs significantly from that in three-dimensional (3D) systems, yet the physics of such low-dimensional systems is generally not very well represented in standard undergraduate or graduate curricula. For instance,…

INHALED CONCENTRATED AMBIENT PARTICLES ARE ASSOCIATED WITH HEMATOLOGIC AND BRONCHOALVEOLAR LAVAGE CHANGES IN CANINES. (R827353C008)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

DIESEL EXHAUST PARTICLES EXERT ACUTE EFFECTS ON AIRWAY INFLAMMATION AND FUNCTION IN MURINE ALLERGEN PROVOCATION MODELS. (R827352C008)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

ENDOTOXIN PRIMING AFFECTS THE LUNG RESPONSE TO ULTRAFINE PARTICLES AND OZONE IN YOUNG AND OLD RATS. (R827354C004)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

SIMULTANEOUS PARTICLE AND MOLECULE MODELING (SPAMM): AN APPROACH FOR COMBINING SECTIONAL AEROSOL EQUATIONS AND ELEMENTARY GAS-PHASE REACTIONS. (R824970)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

COMPARISON OF FREE-LIVING AND PARTICLE-ASSOCIATED BACTERIAL COMMUNITIES IN A COASTAL LAGOON. (R828676C003)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

ULTRAFINE INSOLUBLE IRIDIUM PARTICLES ARE NEGLIGIBLY TRANSLOCATED FROM LUNG EPITHELIUM TO EXTRAPULMONARY ORGANS. (R827354C004)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

CLASSIFICATION OF SINGLE PARTICLES ANALYZED BY ATOFMS USING AN ARTIFICIAL NEURAL NETWORK, ART-2A. (R826371C001)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

ULTRAFINE PARTICLE EXPOSURE ALTERS EXPRESSION OF CD40 LIGAND (CD154) IN HEALTHY SUBJECTS AND SUBJECTS WITH ASTHMA. (R826781)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Accelerator physics and technology challenges of very high energy hadron colliders

NASA Astrophysics Data System (ADS)

Shiltsev, Vladimir D.

2015-08-01

High energy hadron colliders have been in the forefront of particle physics for more than three decades. At present, international particle physics community considers several options for a 100 TeV proton-proton collider as a possible post-LHC energy frontier facility. The method of colliding beams has not fully exhausted its potential but has slowed down considerably in its progress. This paper briefly reviews the accelerator physics and technology challenges of the future very high energy colliders and outlines the areas of required research and development towards their technical and financial feasibility.

Accelerator physics and technology challenges of very high energy hadron colliders

DOE PAGES

Shiltsev, Vladimir D.

2015-08-20

High energy hadron colliders have been in the forefront of particle physics for more than three decades. At present, international particle physics community considers several options for a 100 TeV proton–proton collider as a possible post-LHC energy frontier facility. The method of colliding beams has not fully exhausted its potential but has slowed down considerably in its progress. This article briefly reviews the accelerator physics and technology challenges of the future very high energy colliders and outlines the areas of required research and development towards their technical and financial feasibility.

Nanoscale Design of Nano-Sized Particles in Shape-Memory Polymer Nanocomposites Driven by Electricity

PubMed Central

Lu, Haibao; Huang, Wei Min; Liang, Fei; Yu, Kai

2013-01-01

In the last few years, we have witnessed significant progress in developing high performance shape memory polymer (SMP) nanocomposites, in particular, for shape recovery activated by indirect heating in the presence of electricity, magnetism, light, radio frequency, microwave and radiation, etc. In this paper, we critically review recent findings in Joule heating of SMP nanocomposites incorporated with nanosized conductive electromagnetic particles by means of nanoscale control via applying an electro- and/or magnetic field. A few different nanoscale design principles to form one-/two-/three- dimensional conductive networks are discussed. PMID:28788303

Solid state RF power: The route to 1W per euro cent

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

Heid, Oliver

2013-04-19

In most particle accelerators RF power is a decisive design constraint due to high costs and relative inflexibility of current electron beam based RF sources, i.e. Klystrons, Magnetrons, Tetrodes etc. At VHF/UHF frequencies the transition to solid state devices promises to fundamentally change the situation. Recent progress brings 1 Watt per Euro cent installed cost within reach. We present a Silicon Carbide semiconductor solution utilising the Solid State Direct Drive technology at unprecedented efficiency, power levels and power densities. The proposed solution allows retrofitting of existing RF accelerators and opens the route to novel particle accelerator concepts.

Analysis of particles produced during airbag deployment by scanning electron microscopy with energy dispersive x-ray spectroscopy and their deposition on surrounding surfaces: a mid-research summary

NASA Astrophysics Data System (ADS)

Wyatt, J. Matney

2011-06-01

Airbags can be encountered in forensic work when investigating a car crash and are typically constructed with primerlike material to begin the deployment apparatus. The mechanisms of airbag deployment can produce particles ideal for scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS) analysis. A recent study published by Berk studied airbags with vents and showed that it is possible for particles generated from the deployment of these airbags to deposit on surfaces in the vehicle as the airbags deflate.1 Another paper published by Berk reported particles similar in morphology and composition to primer gunshot residue (GSR) are produced by side impact airbags.2 This paper's aim will be to show mid-point results of a study still in progress in which non-vented airbags were analyzed to determine if they exhibited the same particle depositing features as their vented airbag counterparts. Further investigation in this study is being performed to find more airbags which produce primer gunshot residue-like particles containing lead, barium, and antimony from airbag deployment. To date, the study has resulted in (1) non-vented airbags exhibiting deposition of particles suitable for SEM/EDS analysis and (2) no gunshot residue-like particles being detected from the airbag residues studied thus far.

Particulate Formation from a Copper Oxide-Based Oxygen ...

EPA Pesticide Factsheets

Attrition behavior and particle loss of a copper oxide-based oxygen carrier from a methane chemical looping combustion (CLC) process was investigated in a fluidized bed reactor. The aerodynamic diameters of most elutriated particulates, after passing through a horizontal settling duct, range between 2 and 5 μm. A notable number of submicron particulates are also identified. Oxygen carrier attrition was observed to lead to increased CuO loss resulting from the chemical looping reactions, i.e., Cu is enriched in small particles generated primarily from fragmentation in the size range of 10-75 μm. Cyclic reduction and oxidation reactions in CLC have been determined to weaken the oxygen carrier particles, resulting in increased particulate emission rates when compared to oxygen carriers without redox reactions. The generation rate for particulates < 10 μm was found to decrease with progressive cycles over as-prepared oxygen carrier particles and then reach a steady state. The surface of the oxygen carrier is also found to be coarsened due to a Kirkendall effect, which also explains the enrichment of Cu on particle surfaces and in small particles. As a result, it is important to collect and reprocess small particles generated from chemical looping processes to reduce oxygen carrier loss. The redox reactions associated with chemical looping combustion play an important role in particle attrition in the fluidized bed. Reaction-induced local stresses, due to the r

Gas explosions and thermal runaways during external heating abuse of commercial lithium-ion graphite-LiCoO2 cells at different levels of ageing

NASA Astrophysics Data System (ADS)

Larsson, Fredrik; Bertilsson, Simon; Furlani, Maurizio; Albinsson, Ingvar; Mellander, Bengt-Erik

2018-01-01

Commercial 6.8 Ah lithium-ion cells with different ageing/status have been abused by external heating in an oven. Prior to the abuse test, selected cells were aged either by C/2 cycling up to 300 cycles or stored at 60 °C. Gas emissions were measured by FTIR and three separate vents were identified, two well before the thermal runaway while the third occurred simultaneously with the thermal runaway releasing heavy smoke and gas. Emissions of toxic carbon monoxide (CO), hydrogen fluoride (HF) and phosphorous oxyfluoride (POF3) were detected in the third vent, regardless if there was a fire or not. All abused cells went into thermal runaway and emitted smoke and gas, the working cells also released flames as well as sparks. The dead cells were however less reactive but still underwent thermal runaway. For about half of the working cells, for all levels of cycle ageing, ignition of the accumulated battery released gases occurred about 15 s after the thermal runaway resulting in a gas explosion. The thermal runaway temperature, about 190 °C, varied somewhat for the different cell ageing/status where a weak local minimum was found for cells cycled between 100 and 200 times.

Tunable band alignment in two-phase-coexistence Nb3O7F nanocrystals with enhanced light harvesting and photocatalytic performance

NASA Astrophysics Data System (ADS)

Li, Zhen; Huang, Fei; Feng, Xin; Yan, Aihua; Dong, Haiming; Hu, Miao; Li, Qi

2018-06-01

A two-phase-coexistence technique offers intriguing variables to maneuver novel and enhanced functionality in a single-component material. Most importantly, new band alignment and perfect interfaces between two phases can strongly affect local photoelectronic properties. However, previous efforts to achieve two-phase coexistence were mainly restricted to specific systems and methods. Here we demonstrate a phase-transition route to acquire two-phase-coexistence niobium oxyfluoride (Nb3O7F) nanocrystals for the first time. Based on key distinguishing features of the experimental results and theoretical analysis, the phase transition of Nb3O7F involves an organic/inorganic hybrid, heat treating, Al-doping, lattice deformation and structural rearrangement. The band gap can be effectively tuned from 3.03 eV to 2.84 eV, and the VBM can be tuned from 1.49 eV to 1.69 eV according to the phase proportion. Benefiting from uniform nanocrystal size, tunable band alignment and an optimized interfacial structure, the two-phase coexistence markedly enhances visible-light harvesting and the photocatalytic performance of Nb3O7F nanocrystals. The results not only demonstrate an opportunity to explore two-phase coexistence of novel nanocrystals, but also illustrate the role of two-phase coexistence in achieving enhanced photoelectronic properties.

Tunable band alignment in two-phase-coexistence Nb3O7F nanocrystals with enhanced light harvesting and photocatalytic performance.

PubMed

Li, Zhen; Huang, Fei; Feng, Xin; Yan, Aihua; Dong, Haiming; Hu, Miao; Li, Qi

2018-06-01

A two-phase-coexistence technique offers intriguing variables to maneuver novel and enhanced functionality in a single-component material. Most importantly, new band alignment and perfect interfaces between two phases can strongly affect local photoelectronic properties. However, previous efforts to achieve two-phase coexistence were mainly restricted to specific systems and methods. Here we demonstrate a phase-transition route to acquire two-phase-coexistence niobium oxyfluoride (Nb 3 O 7 F) nanocrystals for the first time. Based on key distinguishing features of the experimental results and theoretical analysis, the phase transition of Nb 3 O 7 F involves an organic/inorganic hybrid, heat treating, Al-doping, lattice deformation and structural rearrangement. The band gap can be effectively tuned from 3.03 eV to 2.84 eV, and the VBM can be tuned from 1.49 eV to 1.69 eV according to the phase proportion. Benefiting from uniform nanocrystal size, tunable band alignment and an optimized interfacial structure, the two-phase coexistence markedly enhances visible-light harvesting and the photocatalytic performance of Nb 3 O 7 F nanocrystals. The results not only demonstrate an opportunity to explore two-phase coexistence of novel nanocrystals, but also illustrate the role of two-phase coexistence in achieving enhanced photoelectronic properties.

Reply to “Structural and magnetic behavior of the cubic oxyfluoride SrFeO{sub 2}F studied by neutron diffraction”

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

Clemens, Oliver, E-mail: oliver.clemens@kit.edu; Karlsruher Institut für Technologie, Institut für Nanotechnologie, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen; Berry, Frank J.

2015-03-15

In this article we comment on the results published by Thompson et al. (, J. Solid State Chem. 219 (2014) 173–178) on the crystal structure of SrFeO{sub 2}F, who claim the compound to crystallize in the cubic space group Pm-3m. We give a more detailed explanation of the determination of our previously reported structural model with Imma symmetry (Clemens et al., J. Solid State Chem. 206 (2013) 158–169), with addition of variable temperature XRD measurements with high counting time to provide unambiguous evidence for the Imma model being correct for our sample. - Graphical abstract: The crystal structure of SrFeO{submore » 2}F is discussed with regards to previous reports. - Highlights: • SrFeO{sub 2}F was synthesized by polymer based fluorination of SrFeO{sub 3}. • Evaluation of the diffraction data shows a pseudocubic cell metric. • Superstructure reflections at low d-spacings indicate deviation from cubic symmetry. • The phase transition temperature from orthorhombic to cubic was determined using variable temperature X-ray diffraction. • Results published by Thompson et al. are critically discussed with respect to those observations.« less

MULTI-STAGE DELIVERY NANO-PARTICLE SYSTEMS FOR THERAPEUTIC APPLICATIONS

PubMed Central

Serda, Rita E.; Godin, Biana; Blanco, Elvin; Chiappini, Ciro; Ferrari, Mauro

2010-01-01

Background The daunting task for drug molecules to reach pathological lesions has fueled rapid advances in Nanomedicine. The progressive evolution of nanovectors has led to the development of multi-stage delivery systems aimed at overcoming the numerous obstacles encountered by nanovectors on their journey to the target site. Scope of Review This review summarizes major findings with respect to silicon-based drug delivery vectors for cancer therapeutics and imaging. Based on rational design, well established silicon technologies have been adapted for the fabrication of nanovectors with specific shapes, sizes, and porosities. These vectors are part of a multi-stage delivery system that contains multiple nano-components, each designed to achieve a specific task with the common goal of site-directed delivery of therapeutics. Major Conclusions Quasi-hemispherical and discoidal silicon microparticles are superior to spherical particles with respect to margination in the blood, with particles of different shapes and sizes having unique distributions in vivo. Cellular adhesion and internalization of silicon microparticles is influenced by microparticle shape and surface charge, with the latter dictating binding of serum opsonins. Based on in vitro cell studies, the internalization of porous silicon microparticles by endothelial cells and macrophages is compatible with cellular morphology, intracellular trafficking, mitosis, cell cycle progression, cytokine release, and cell viability. In vivo studies support superior therapeutic efficacy of liposomal encapsulated siRNA when delivered in multi-stage systems compared to free nanoparticles. PMID:20493927

Evolution of network architecture in a granular material under compression

NASA Astrophysics Data System (ADS)

Papadopoulos, Lia; Puckett, James G.; Daniels, Karen E.; Bassett, Danielle S.

2016-09-01

As a granular material is compressed, the particles and forces within the system arrange to form complex and heterogeneous collective structures. Force chains are a prime example of such structures, and are thought to constrain bulk properties such as mechanical stability and acoustic transmission. However, capturing and characterizing the evolving nature of the intrinsic inhomogeneity and mesoscale architecture of granular systems can be challenging. A growing body of work has shown that graph theoretic approaches may provide a useful foundation for tackling these problems. Here, we extend the current approaches by utilizing multilayer networks as a framework for directly quantifying the progression of mesoscale architecture in a compressed granular system. We examine a quasi-two-dimensional aggregate of photoelastic disks, subject to biaxial compressions through a series of small, quasistatic steps. Treating particles as network nodes and interparticle forces as network edges, we construct a multilayer network for the system by linking together the series of static force networks that exist at each strain step. We then extract the inherent mesoscale structure from the system by using a generalization of community detection methods to multilayer networks, and we define quantitative measures to characterize the changes in this structure throughout the compression process. We separately consider the network of normal and tangential forces, and find that they display a different progression throughout compression. To test the sensitivity of the network model to particle properties, we examine whether the method can distinguish a subsystem of low-friction particles within a bath of higher-friction particles. We find that this can be achieved by considering the network of tangential forces, and that the community structure is better able to separate the subsystem than a purely local measure of interparticle forces alone. The results discussed throughout this study suggest that these network science techniques may provide a direct way to compare and classify data from systems under different external conditions or with different physical makeup.

Plasma Accelerators Race to 10 GeV and Beyond

NASA Astrophysics Data System (ADS)

Katsouleas, Tom

2005-10-01

This paper reviews the concepts, recent progress and current challenges for realizing the tremendous electric fields in relativistic plasma waves for applications ranging from tabletop particle accelerators to high-energy physics. Experiments in the 90's on laser-driven plasma wakefield accelerators at several laboratories around the world demonstrated the potential for plasma wakefields to accelerate intense bunches of self-trapped particles at rates as high as 100 GeV/m in mm-scale gas jets. These early experiments offered impressive gradients but large energy spread (100%) and short interaction lengths. Major breakthroughs have recently occurred on both fronts. Three groups (LBL-US, LOA-France and RAL-UK) have now entered a new regime of laser wakefield acceleration resulting in 100 MeV mono-energetic beams with up to nanoCoulombs of charge and very small angular spread. Simulations suggest that current lasers are just entering this new regime, and the scaling to higher energies appears attractive. In parallel with the progress in laser-driven wakefields, particle-beam driven wakefield accelerators are making large strides. A series of experiments using the 30 GeV beam of the Stanford Linear Accelerator Center (SLAC) has demonstrated high-gradient acceleration of electrons and positrons in meter-scale plasmas. The UCLA/USC/SLAC collaboration has accelerated electrons beyond 1 GeV and is aiming at 10 GeV in 30 cm as the next step toward a ``plasma afterburner,'' a concept for doubling the energy of a high-energy collider in a few tens of meters of plasma. In addition to wakefield acceleration, these and other experiments have demonstrated the rich physics bounty to be reaped from relativistic beam-plasma interactions. This includes plasma lenses capable of focusing particle beams to the highest density ever produced, collective radiation mechanisms capable of generating high-brightness x-ray beams, collective refraction of particles at a plasma interface, and acceleration of intense proton beams from laser-irradiated foils.

Zooplankton Grazing Effects on Particle Size Spectra under Different Seasonal Conditions

NASA Astrophysics Data System (ADS)

Stamieszkin, K.; Poulton, N.; Pershing, A. J.

2016-02-01

Oceanic particle size spectra can be used to explain and predict variability in carbon export efficiency, since larger particles are more likely to sink to depth than small particles. The distribution of biogenic particle size in the surface ocean is the result of many variables and processes, including nutrient availability, primary productivity, aggregation, remineralization, and grazing. We conducted a series of grazing experiments to test the hypothesis that mesozooplankton shift particle size spectra toward larger particles, via grazing and egestion of relatively large fecal pellets. These experiments were carried out over several months, and used natural communities of mesozooplankton and their microbial prey, collected offshore of the Damariscotta River in the Gulf of Maine. We analyzed the samples using Fluid Imaging Technologies' FlowCam®, a particle imaging system. With this equipment, we processed live samples, decreasing the likelihood of losing or damaging fragile particles, and thereby lessening sources of error in commonly used preservation and enumeration protocols. Our results show how the plankton size spectrum changes as the Gulf of Maine progresses through a seasonal cycle. We explore the relationship of grazing community size structure to its effect on the overall biogenic particle size spectrum. At some times of year, mesozooplankton grazing does not alter the particle size spectrum, while at others it significantly does, affecting the potential for biogenic flux. We also examine prey selectivity, and find that chain diatoms are the only prey group preferentially consumed. Otherwise, we find that complete mesozooplankton communities are "evolved" to fit their prey such that most prey groups are grazed evenly. We discuss a metabolic numerical model which could be used to universalize the relationships between whole gazer and whole microbial communities, with respect to effects on particle size spectra.

Pushing, pulling and electromagnetic radiation force cloaking by a pair of conducting cylindrical particles

NASA Astrophysics Data System (ADS)

Mitri, F. G.

2018-02-01

The present analysis shows that two conducting cylindrical particles illuminated by an axially-polarized electric field of plane progressive waves at arbitrary incidence will attract, repel or become totally cloaked (i.e., invisible to the transfer of linear momentum carried by the incident waves), depending on their sizes, the interparticle distance as well as the angle of incidence of the incident field. Based on the rigorous multipole expansion method and the translational addition theorem of cylindrical wave functions, the electromagnetic (EM) radiation forces arising from multiple scattering effects between a pair of perfectly conducting cylindrical particles of circular cross-sections are derived and computed. An effective incident field on a particular particle is determined first, and used subsequently with its corresponding scattered field to derive the closed-form analytical expressions for the radiation force vector components. The mathematical expressions for the EM radiation force components (i.e. longitudinal and transverse) are exact, and have been formulated in partial-wave series expansions in cylindrical coordinates involving the angle of incidence, the interparticle distance and the expansion coefficients. Numerical examples illustrate the analysis for two perfectly conducting circular cylinders in a homogeneous nonmagnetic medium of wave propagation. The computations for the dimensionless radiation force functions are performed with particular emphasis on varying the angle of incidence, the interparticle distance, and the sizes of the particles. Depending on the interparticle distance and angle of incidence, the cylinders yield total neutrality (or invisibility); they experience no force and become unresponsive to the transfer of the EM linear momentum due to multiple scattering cancellation effects. Moreover, pushing or pulling EM forces between the two cylinders arise depending on the interparticle distance, the angle of incidence and their size parameters. This study provides a complete analytical method and computations for the longitudinal and transverse radiation force components in the multiple scattering of EM plane progressive waves with potential applications in particle manipulation, optically-engineered metamaterials with reconfigurable periodicities and cloaking devices to name a few examples.

Recent progress in the physics of microfluidics and related biotechnological applications.

PubMed

Tabeling, Patrick

2014-02-01

Since the mid-nineties, the physical understanding of microfluidic flows has reached a level sufficiently elaborate for envisaging applications in all sorts of domains. As the domain expanded, the existence of new situations where fluid dynamics at small or moderate Reynolds numbers combines with confinement, interfaces, transport, particles along with disordered substrates raised new challenges. The present review is restricted to three domains in which progress in the physical description has been made recently (droplet-based, inertial and paper-based microfluidics) and for which biotechnological applications are foreseeable. Copyright © 2013 Elsevier Ltd. All rights reserved.

Solid-State Division progress report for period ending March 31, 1983

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

Green, P.H.; Watson, D.M.

1983-09-01

Progress and activities are reported on: theoretical solid-state physics (surfaces; electronic, vibrational, and magnetic properties; particle-solid interactions; laser annealing), surface and near-surface properties of solids (surface, plasma-material interactions, ion implantation and ion-beam mixing, pulsed-laser and thermal processing), defects in solids (radiation effects, fracture, impurities and defects, semiconductor physics and photovoltaic conversion), transport properties of solids (fast-ion conductors, superconductivity, mass and charge transport in materials), neutron scattering (small-angle scattering, lattice dynamics, magnetic properties, structure and instrumentation), and preparation and characterization of research materials (growth and preparative methods, nuclear waste forms, special materials). (DLC)

Adaptive measurement selection for progressive damage estimation

NASA Astrophysics Data System (ADS)

Zhou, Wenfan; Kovvali, Narayan; Papandreou-Suppappola, Antonia; Chattopadhyay, Aditi; Peralta, Pedro

2011-04-01

Noise and interference in sensor measurements degrade the quality of data and have a negative impact on the performance of structural damage diagnosis systems. In this paper, a novel adaptive measurement screening approach is presented to automatically select the most informative measurements and use them intelligently for structural damage estimation. The method is implemented efficiently in a sequential Monte Carlo (SMC) setting using particle filtering. The noise suppression and improved damage estimation capability of the proposed method is demonstrated by an application to the problem of estimating progressive fatigue damage in an aluminum compact-tension (CT) sample using noisy PZT sensor measurements.

Recent Progress in the Study of Topological Semimetals

NASA Astrophysics Data System (ADS)

Bernevig, Andrei; Weng, Hongming; Fang, Zhong; Dai, Xi

2018-04-01

The topological semimetal is a new, theoretically predicted and experimentally discovered, topological state of matter. In one of its several realizations, the topological semimetal hosts Weyl fermions, elusive particles predicted more than 85 years ago, sought after in high-energy experiments, but only recently found in a condensed-matter setting. In the present review, we catalogue the most recent progress in this fast-developing research field. We give special attention to topological invariants and the material realization of three different types of topological semimetal. We also discuss various photo emission, transport and optical experimental observables that characterize the appearance of topological semimetal phases.

Defect and void evolution in oxide dispersion strengthened ferritic steels under 3.2 MeV Fe + ion irradiation with simultaneous helium injection

NASA Astrophysics Data System (ADS)

Kim, I.-S.; Hunn, J. D.; Hashimoto, N.; Larson^1, D. L.; Maziasz, P. J.; Miyahara, K.; Lee, E. H.

2000-08-01

In an attempt to explore the potential of oxide dispersion strengthened (ODS) ferritic steels for fission and fusion structural materials applications, a set of ODS steels with varying oxide particle dispersion were irradiated at 650°C, using 3.2 MeV Fe + and 330 keV He + ions simultaneously. The void formation mechanisms in these ODS steels were studied by juxtaposing the response of a 9Cr-2WVTa ferritic/martensitic steel and solution annealed AISI 316LN austenitic stainless steel under the same irradiation conditions. The results showed that void formation was suppressed progressively by introducing and retaining a higher dislocation density and finer precipitate particles. Theoretical analyses suggest that the delayed onset of void formation in ODS steels stems from the enhanced point defect recombination in the high density dislocation microstructure, lower dislocation bias due to oxide particle pinning, and a very fine dispersion of helium bubbles caused by trapping helium atoms at the particle-matrix interfaces.

cisTEM, user-friendly software for single-particle image processing.

PubMed

Grant, Timothy; Rohou, Alexis; Grigorieff, Nikolaus

2018-03-07

We have developed new open-source software called cis TEM (computational imaging system for transmission electron microscopy) for the processing of data for high-resolution electron cryo-microscopy and single-particle averaging. cis TEM features a graphical user interface that is used to submit jobs, monitor their progress, and display results. It implements a full processing pipeline including movie processing, image defocus determination, automatic particle picking, 2D classification, ab-initio 3D map generation from random parameters, 3D classification, and high-resolution refinement and reconstruction. Some of these steps implement newly-developed algorithms; others were adapted from previously published algorithms. The software is optimized to enable processing of typical datasets (2000 micrographs, 200 k - 300 k particles) on a high-end, CPU-based workstation in half a day or less, comparable to GPU-accelerated processing. Jobs can also be scheduled on large computer clusters using flexible run profiles that can be adapted for most computing environments. cis TEM is available for download from cistem.org. © 2018, Grant et al.

An improved model for computing the trajectories of conductive particles in roll-type electrostatic separator for recycling metals from WEEE.

PubMed

Wu, Jiang; Li, Jia; Xu, Zhenming

2009-08-15

Electrostatic separation presents an effective and environmentally friendly way for recycling metals and nonmetals from ground waste electrical and electronic equipment (WEEE). For this process, the trajectory of conductive particle is significant and some models have been established. However, the results of previous researches are limited by some simplifying assumptions and lead to a notable discrepancy between the model prediction and the experimental results. In the present research, a roll-type corona-electrostatic separator and ground printed circuit board (PCB) wastes were used to investigate the trajectory of the conductive particle. Two factors, the air drag force and the different charging situation, were introduced into the improved model. Their effects were analyzed and an improved model for the theoretical trajectory of conductive particle was established. Compared with the previous one, the improved model shows a good agreement with the experimental results. It provides a positive guidance for designing of separator and makes a progress for recycling the metals and nonmetals from WEEE.

Swelling, Structure, and Phase Stability of Soft, Compressible Microgels

NASA Astrophysics Data System (ADS)

Denton, Alan R.; Urich, Matthew

Microgels are soft colloidal particles that swell when dispersed in a solvent. The equilibrium particle size is governed by a delicate balance of osmotic pressures, which can be tuned by varying single-particle properties and externally controlled conditions, such as temperature, pH, ionic strength, and concentration. Because of their tunable size and ability to encapsulate dye or drug molecules, microgels have practical relevance for biosensing, drug delivery, carbon capture, and filtration. Using Monte Carlo simulation, we model suspensions of microgels that interact via Hertzian elastic interparticle forces and can expand or contract via trial size changes governed by the Flory-Rehner free energy of cross-linked polymer gels. We analyze the influence of particle compressibility and size fluctuations on bulk structural and thermal properties by computing swelling ratios, radial distribution functions, static structure factors, osmotic pressures, and freezing densities. With increasing density, microgels progressively deswell and their intrinsic polydispersity broadens, while compressibility acts to forestall crystallization. This work was supported by the National Science Foundation under Grant No. DMR- 1106331.

cisTEM, user-friendly software for single-particle image processing

PubMed Central

2018-01-01

We have developed new open-source software called cisTEM (computational imaging system for transmission electron microscopy) for the processing of data for high-resolution electron cryo-microscopy and single-particle averaging. cisTEM features a graphical user interface that is used to submit jobs, monitor their progress, and display results. It implements a full processing pipeline including movie processing, image defocus determination, automatic particle picking, 2D classification, ab-initio 3D map generation from random parameters, 3D classification, and high-resolution refinement and reconstruction. Some of these steps implement newly-developed algorithms; others were adapted from previously published algorithms. The software is optimized to enable processing of typical datasets (2000 micrographs, 200 k – 300 k particles) on a high-end, CPU-based workstation in half a day or less, comparable to GPU-accelerated processing. Jobs can also be scheduled on large computer clusters using flexible run profiles that can be adapted for most computing environments. cisTEM is available for download from cistem.org. PMID:29513216

Visualized effect of oxidation on magnetic recording fidelity in pseudo-single-domain magnetite particles

PubMed Central

Almeida, Trevor P.; Kasama, Takeshi; Muxworthy, Adrian R.; Williams, Wyn; Nagy, Lesleis; Hansen, Thomas W.; Brown, Paul D.; Dunin-Borkowski, Rafal E.

2014-01-01

Magnetite (Fe3O4) is an important magnetic mineral to Earth scientists, as it carries the dominant magnetic signature in rocks, and the understanding of its magnetic recording fidelity provides a critical tool in the field of palaeomagnetism. However, reliable interpretation of the recording fidelity of Fe3O4 particles is greatly diminished over time by progressive oxidation to less magnetic iron oxides, such as maghemite (γ-Fe2O3), with consequent alteration of remanent magnetization potentially having important geological significance. Here we use the complementary techniques of environmental transmission electron microscopy and off-axis electron holography to induce and visualize the effects of oxidation on the magnetization of individual nanoscale Fe3O4 particles as they transform towards γ-Fe2O3. Magnetic induction maps demonstrate a change in both strength and direction of remanent magnetization within Fe3O4 particles in the size range dominant in rocks, confirming that oxidation can modify the original stored magnetic information. PMID:25300366

Visualized effect of oxidation on magnetic recording fidelity in pseudo-single-domain magnetite particles.

PubMed

Almeida, Trevor P; Kasama, Takeshi; Muxworthy, Adrian R; Williams, Wyn; Nagy, Lesleis; Hansen, Thomas W; Brown, Paul D; Dunin-Borkowski, Rafal E

2014-10-10

Magnetite (Fe3O4) is an important magnetic mineral to Earth scientists, as it carries the dominant magnetic signature in rocks, and the understanding of its magnetic recording fidelity provides a critical tool in the field of palaeomagnetism. However, reliable interpretation of the recording fidelity of Fe3O4 particles is greatly diminished over time by progressive oxidation to less magnetic iron oxides, such as maghemite (γ-Fe2O3), with consequent alteration of remanent magnetization potentially having important geological significance. Here we use the complementary techniques of environmental transmission electron microscopy and off-axis electron holography to induce and visualize the effects of oxidation on the magnetization of individual nanoscale Fe3O4 particles as they transform towards γ-Fe2O3. Magnetic induction maps demonstrate a change in both strength and direction of remanent magnetization within Fe3O4 particles in the size range dominant in rocks, confirming that oxidation can modify the original stored magnetic information.

Spin-dependent post-Newtonian parameters from EMRI computation in Kerr background

NASA Astrophysics Data System (ADS)

Friedman, John; Le Tiec, Alexandre; Shah, Abhay

2013-04-01

Because the extreme mass-ratio inspiral (EMRI) approximation is accurate to all orders in v/c, it can be used to find high order post-Newtonian parameters that are not yet analytically accessible. We report here on progress in computing spin-dependent, conservative, post-Newtonian parameters from a radiation-gauge computation for a particle in circular orbit in a family of Kerr geometries. For a particle with 4-velocity u^α= U k^α, with k^α the helical Killing vector of the perturbed spacetime, the renormalized perturbation δU, when written as a function of the particle's angular velocity, is invariant under gauge transformations generated by helically symmetric vectors. The EMRI computations are done in a modified radiation gauge. Extracted parameters are compared to previously known and newly computed spin-dependent post-Newtonian terms. This work is modeled on earlier computations by Blanchet, Detweiler, Le Tiec and Whiting of spin-independent terms for a particle in circular orbit in a Schwarzschild geometry.

Rare earth nanoparticles prevent retinal degeneration induced by intracellular peroxides:

NASA Astrophysics Data System (ADS)

Chen, Junping; Patil, Swanand; Seal, Sudipta; McGinnis, James F.

2006-11-01

Photoreceptor cells are incessantly bombarded with photons of light, which, along with the cells' high rate of oxygen metabolism, continuously exposes them to elevated levels of toxic reactive oxygen intermediates (ROIs). Vacancy-engineered mixed-valence-state cerium oxide nanoparticles (nanoceria particles) scavenge ROIs. Our data show that nanoceria particles prevent increases in the intracellular concentrations of ROIs in primary cell cultures of rat retina and, in vivo, prevent loss of vision due to light-induced degeneration of photoreceptor cells. These data indicate that the nanoceria particles may be effective in inhibiting the progression of ROI-induced cell death, which is thought to be involved in macular degeneration, retinitis pigmentosa and other blinding diseases, as well as the ROI-induced death of other cell types in diabetes, Alzheimer's disease, atherosclerosis, stroke and so on. The use of nanoceria particles as a direct therapy for multiple diseases represents a novel strategy and suggests that they may represent a unique platform technology.

[The analytical setting of rotary speed of centrifuge rotor and centrifugation time in chemical, biochemical and microbiological practice].

PubMed

Zolotarev, K V

2012-08-01

The researchers happen to face with suspensions in their chemical, biochemical and microbiological practice. The suspensions are the disperse systems with solid dispersed phase and liquid dispersion medium and with dispersed phase particle size > 100 nm (10-7 m). Quite often the necessity occurs to separate solid particles from liquid. To use for this purpose the precipitation in gravitation field can make the process to progress too long. In this respect an effective mode is the precipitation in the field of centrifugal forces--the centrifugation. The rotary speed of centrifuge rotor and centrifugation time can be set analytically using regularities of general dynamics and hydrodynamics. To this effect, should be written and transformed the equation of First and Second Newton Laws for suspension particle being in the field of centrifugal forces and forces of resistance of liquid and vessel wall. The force of liquid resistance depends on particle motion condition in liquid. To determine the regimen the Archimedes and Reynolds numerical dimensionless criteria are to be applied. The article demonstrates the results of these transformations as analytical inverse ratio dependence of centrifugation time from rotary speed. The calculation of series of "rate-time" data permits to choose the optimal data pair on the assumption of centrifuge capacity and practical reasonability. The results of calculations are validated by actual experimental data hence the physical mathematical apparatus can be considered as effective one. The setting progress depends both from parameter (Reynolds criterion) and data series calculation. So, the most convenient way to apply this operation is the programming approach. The article proposes to use the program Microsoft Excel and VBA programming language for this purpose. The possibility to download the file from Internet to use it for fast solution is proposed.

Advances in 4D Treatment Planning for Scanned Particle Beam Therapy — Report of Dedicated Workshops

PubMed Central

Bert, Christoph; Graeff, Christian; Riboldi, Marco; Nill, Simeon; Baroni, Guido; Knopf, Antje-Christin

2014-01-01

We report on recent progress in the field of mobile tumor treatment with scanned particle beams, as discussed in the latest editions of the 4D treatment planning workshop. The workshop series started in 2009, with about 20 people from 4 research institutes involved, all actively working on particle therapy delivery and development. The first workshop resulted in a summary of recommendations for the treatment of mobile targets, along with a list of requirements to apply these guidelines clinically. The increased interest in the treatment of mobile tumors led to a continuously growing number of attendees: the 2012 edition counted more than 60 participants from 20 institutions and commercial vendors. The focus of research discussions among workshop participants progressively moved from 4D treatment planning to complete 4D treatments, aiming at effective and safe treatment delivery. Current research perspectives on 4D treatments include all critical aspects of time resolved delivery, such as in-room imaging, motion detection, beam application, and quality assurance techniques. This was motivated by the start of first clinical treatments of hepato cellular tumors with a scanned particle beam, relying on gating or abdominal compression for motion mitigation. Up to date research activities emphasize significant efforts in investigating advanced motion mitigation techniques, with a specific interest in the development of dedicated tools for experimental validation. Potential improvements will be made possible in the near future through 4D optimized treatment plans that require upgrades of the currently established therapy control systems for time resolved delivery. But since also these novel optimization techniques rely on the validity of the 4DCT, research focusing on alternative 4D imaging technique, such as MRI based 4DCT generation will continue. PMID:24354749

Planetary surface photometry and imaging: progress and perspectives.

PubMed

Goguen, Jay D

2014-10-01

Spacecraft have visited and returned many thousands of images and spectra of all of the planets, many of their moons, several asteroids, and a few comet nuclei during the golden age of planetary exploration. The signal in each pixel of each image or spectral channel is a measurement of the radiance of scattered sunlight into a specific direction. The information on the structure and composition of the surface that is contained in variation of the radiance with scattering geometry and wavelength, including polarization state, has only just begun to be exploited and is the topic of this review. The uppermost surfaces of these bodies are mainly composed of particles that are continuously generated by impacts of micrometeoroids and larger impactors. Models of light scattering by distributions of sizes and irregular shapes of particles and by closely packed particles within a surface are challenging. These are active topics of research where considerable progress has recently been made. We focus on the surfaces of bodies lacking atmospheres.These surfaces are diverse and their morphologies give evidence of their evolution by impacts and resurfacing by a variety of processes including down slope movement and electrostatic transport of particles, gravitational accumulation of debris, volatile outgassing and migration, and magnetospheric interactions. Sampling of scattering geometries and spatial resolution is constrained by spacecraft trajectories. However, the large number of archived images and spectra demand more quantitative interpretation. The scattering geometry dependence of the radiance is underutilized and promises constraints on the compositions and structure of the surface for materials that lack diagnostic wavelength dependence. The general problem is considered in terms of the lunar regolith for which samples have been returned to Earth.

Particle shape-controlled sorting and transport behaviour of mixed siliciclastic/bioclastic sediments in a mesotidal lagoon, South Africa

NASA Astrophysics Data System (ADS)

Flemming, Burghard W.

2017-08-01

This study investigates the effect of particle shape on the transport and deposition of mixed siliciclastic-bioclastic sediments in the lower mesotidal Langebaan Lagoon along the South Atlantic coast of South Africa. As the two sediment components have undergone mutual sorting for the last 7 ka, they can be expected to have reached a highest possible degree of hydraulic equivalence. A comparison of sieve and settling tube data shows that, with progressive coarsening of the size fractions, the mean diameters of individual sediment components increasingly depart from the spherical quartz standard, the experimental data demonstrating the hydraulic incompatibility of the sieve data. Overall, the spatial distribution patterns of textural parameters (mean settling diameter, sorting and skewness) of the siliciclastic and bioclastic sediment components are very similar. Bivariate plots between them reveal linear trends when averaged over small intervals. A systematic deviation is observed in sorting, the trend ranging from uniformity at poorer sorting levels to a progressively increasing lag of the bioclastic component relative to the siliciclastic one as overall sorting improves. The deviation amounts to 0.8 relative sorting units at the optimal sorting level. The small textural differences between the two components are considered to reflect the influence of particle shape, which prevents the bioclastic fraction from achieving complete textural equivalence with the siliciclastic one. This is also reflected in the inferred transport behaviour of the two shape components, the bioclastic fraction moving closer to the bed than the siliciclastic one because of the higher drag experienced by low shape factor particles. As a consequence, the bed-phase development of bioclastic sediments departs significantly from that of siliciclastic sediments. Systematic flume experiments, however, are currently still lacking.

Short-wavelength plasma turbulence and temperature anisotropy instabilities: Recent computational progress

DOE PAGES

Gary, S. Peter

2015-04-06

Plasma turbulence consists of an ensemble of enhanced, broadband electromagnetic fluctuations, typically driven by multi-wave interactions which transfer energy in wavevector space via non- linear cascade processes. In addition, temperature anisotropy instabilities in collisionless plasmas are driven by quasi-linear wave–particle interactions which transfer particle kinetic energy to field fluctuation energy; the resulting enhanced fluctuations are typically narrowband in wavevector magnitude and direction. Whatever their sources, short-wavelength fluctuations are those at which charged particle kinetic, that is, velocity-space, properties are important; these are generally wavelengths of the order of or shorter than the ion inertial length or the thermal ion gyroradius.more » The purpose of this review is to summarize and interpret recent computational results concerning short-wavelength plasma turbulence, short-wavelength temperature anisotropy instabilities and relationships between the two phenomena.« less

A fluid description of plasma double-layers

NASA Technical Reports Server (NTRS)

Levine, J. S.; Crawford, F. W.

1979-01-01

The space-charge double-layer that forms between two plasmas with different densities and thermal energies was investigated using three progressively realistic models which are treated by fluid theory, and take into account four species of particles: electrons and ions reflected by the double-layer, and electrons and ions transmitted through it. The two plasmas are assumed to be cold, and the self-consistent potential, electric field and space-charge distributions within the double-layer are determined. The effects of thermal velocities are taken into account for the reflected particles, and the modifications to the cold plasma solutions are established. Further modifications due to thermal velocities of the transmitted particles are examined. The applicability of a one dimensional fluid description, rather than plasma kinetic theory, is discussed. Theoretical predictions are compared with double layer potentials and lengths deduced from laboratory and space plasma experiments.

SERDP and ESTCP Workshop on Research and Development Needs for Long-Term Management of Contaminated Sediments

DTIC Science & Technology

2012-10-01

protective of subsistence fishers at an excess life time cancer risk of 1 in one million (1 × 10-6). The trophic transfer model, which is calibrated...In Progress) ER-2135-11, Application of Biofilm Covered Activated Carbon Particles as a Microbial Inoculum Delivery System for Enhanced

NANO-SCALE METAL OXIDE PARTICLES/CLUSTERS AS CHEMICAL REAGENTS: SYNTHESIS AND PROPERTIES OF ULTRA-HIGH SURFACE AREA MAGNESIUM OXIDE. (R825549C015)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

MEASUREMENT OF RURAL SULFUR DIOXIDE AND PARTICLE SULFATE: ANALYSIS OF CASTNET DATA, 1987 - 1996

EPA Science Inventory

The Clean Sir Status and Trends Network (CASTNet) was implemented by the U.S. Environmental Protection Agency (EPA) in 1991 in response to Title IX of the Clean Air Amendments of 1990, which mandated the deployment of a national ambient air monitoring network to track progress of...

RESPIRATORY DISEASE AS A CONTRIBUTING CAUSE OF NON-RESPIRATORY MORTALITY ASSOCIATIONS WITH PARTICLE MASS IN 5 U.S. CITIES. (R825271)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Tracking in 4 dimensions

DOE PAGES

Cartiglia, N.; Arcidiacono, R.; Baldassarri, B.; ...

2016-06-03

In this contribution we will review the progresses toward the construction of a tracking system able to measure the passage of charged particles with a combined precision of ~10 ps and ~10 μm, either using a single type of sensor, able to concurrently measure position and time, or a combination of position and time sensors.

A NUMERICAL CHARACTERIZATION OF PARTICLE BEAM COLLIMATION BY AN AERODYNAMIC LENS-NOZZLE SYSTEM PART I: AN INDIVIDUAL LENS OR NOZZLE. (R825391)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

SYSTEMIC, MUCOSAL AND HETEROTYPIC IMMUNE INDUCTION IN MICE INOCULATED WITH VENEZUELAN EQUINE ENCEPHALITIS REPLICONS EXPRESSING NORWALK VIRUS-LIKE PARTICLES. (R826139)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

PARTICLE CONCENTRATIONS IN INNER-CITY HOMES OF CHILDREN WITH ASTHMA: THE EFFECT OF SMOKING, COOKING AND OUTDOOR POLLUTION. (R827355C002)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

JPL in-house fluidized bed reactor research

NASA Technical Reports Server (NTRS)

Rohatgi, N. K.

1985-01-01

The progress in the in-house program on the silane fluidized-bed system is reported. A seed-particle cleaning procedure was developed to obtain material purity near the level required to produce a semiconductor-grade product. The liner-seal design was consistently proven to withstand heating/cooling cycles in all of the experimental runs.

THIOL ANTIOXIDANTS INHIBIT THE ADJUVANT EFFECTS OF AEROSOLIZED DIESEL EXHAUST PARTICLES IN A MURINE MODEL FOR OVALBUMIN SENSITIZATION. (R827352C008)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

THIOL ANTIOXIDANTS INHIBIT THE ADJUVANT EFFECTS OF AEROSOLIZED DIESEL EXHAUST PARTICLES IN A MURINE MODEL FOR OVALBUMIN SENSITIZATION. (R827352C001)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

INDUCTION OF HEME OXYGENASE-1 EXPRESSION IN MACROPHAGES BY DIESEL EXHAUST PARTICLE CHEMICALS AND QUINONES VIA THE ANTIOXIDANT-RESPONSIVE ELEMENT. (R827352C001)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

THE ROLE OF A MITOCHONDRIAL PATHWAY IN THE INDUCTION OF APOPTOSIS BY CHEMICALS EXTRACTED FROM DIESEL EXHAUST PARTICLES. (R827352C001)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

ENDOTOXIN PRIMING, OZONE EXPOSURE, AND AGE AFFECT ULTRAFINE PARTICLE-INDUCED INFLAMMATION AND ANTIOXIDANT GENE EXPRESSION IN MOUSE LUNG AND HEART. (R827354C005)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

INHALATION OF ULTRAFINE PARTICLES HAS NO EFFECT ON IMMUNE RESPONSE AND AIRWAY REACTIVITY IN A BEAGLE DOG MODEL OF ALLERGIC ASTHMA. (R826442)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

ULTRAFINE PARTICLE EXPOSURE ALTERS EXPRESSION OF CD40 LIGAND (CD154) IN HEALTHY SUBJECTS AND SUBJECTS WITH ASTHMA. (R827354C003)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Computational study of scattering of a zero-order Bessel beam by large nonspherical homogeneous particles with the multilevel fast multipole algorithm

NASA Astrophysics Data System (ADS)

Yang, Minglin; Wu, Yueqian; Sheng, Xinqing; Ren, Kuan Fang

2017-12-01

Computation of scattering of shaped beams by large nonspherical particles is a challenge in both optics and electromagnetics domains since it concerns many research fields. In this paper, we report our new progress in the numerical computation of the scattering diagrams. Our algorithm permits to calculate the scattering of a particle of size as large as 110 wavelengths or 700 in size parameter. The particle can be transparent or absorbing of arbitrary shape, smooth or with a sharp surface, such as the Chebyshev particles or ice crystals. To illustrate the capacity of the algorithm, a zero order Bessel beam is taken as the incident beam, and the scattering of ellipsoidal particles and Chebyshev particles are taken as examples. Some special phenomena have been revealed and examined. The scattering problem is formulated with the combined tangential formulation and solved iteratively with the aid of the multilevel fast multipole algorithm, which is well parallelized with the message passing interface on the distributed memory computer platform using the hybrid partitioning strategy. The numerical predictions are compared with the results of the rigorous method for a spherical particle to validate the accuracy of the approach. The scattering diagrams of large ellipsoidal particles with various parameters are examined. The effect of aspect ratios, as well as half-cone angle of the incident zero-order Bessel beam and the off-axis distance on scattered intensity, is studied. Scattering by asymmetry Chebyshev particle with size parameter larger than 700 is also given to show the capability of the method for computing scattering by arbitrary shaped particles.

Fracture of a Brittle-Particle Ductile Matrix Composite with Applications to a Coating System

NASA Astrophysics Data System (ADS)

Bianculli, Steven J.

In material systems consisting of hard second phase particles in a ductile matrix, failure initiating from cracking of the second phase particles is an important failure mechanism. This dissertation applies the principles of fracture mechanics to consider this problem, first from the standpoint of fracture of the particles, and then the onset of crack propagation from fractured particles. This research was inspired by the observation of the failure mechanism of a commercial zinc-based anti-corrosion coating and the analysis was initially approached as coatings problem. As the work progressed it became evident that failure mechanism was relevant to a broad range of composite material systems and research approach was generalized to consider failure of a system consisting of ellipsoidal second phase particles in a ductile matrix. The starting point for the analysis is the classical Eshelby Problem, which considered stress transfer from the matrix to an ellipsoidal inclusion. The particle fracture problem is approached by considering cracks within particles and how they are affected by the particle/matrix interface, the difference in properties between the particle and matrix, and by particle shape. These effects are mapped out for a wide range of material combinations. The trends developed show that, although the particle fracture problem is very complex, the potential for fracture among a range of particle shapes can, for certain ranges in particle shape, be considered easily on the basis of the Eshelby Stress alone. Additionally, the evaluation of cracks near the curved particle/matrix interface adds to the existing body of work of cracks approaching bi-material interfaces in layered material systems. The onset of crack propagation from fractured particles is then considered as a function of particle shape and mismatch in material properties between the particle and matrix. This behavior is mapped out for a wide range of material combinations. The final section of this dissertation qualitatively considers an approach to determine critical particle sizes, below which crack propagation will not occur for a coating system that exhibited stable cracks in an interfacial layer between the coating and substrate.

Overview of progress in European medium sized tokamaks towards an integrated plasma-edge/wall solution

NASA Astrophysics Data System (ADS)

Meyer, H.; Eich, T.; Beurskens, M.; Coda, S.; Hakola, A.; Martin, P.; Adamek, J.; Agostini, M.; Aguiam, D.; Ahn, J.; Aho-Mantila, L.; Akers, R.; Albanese, R.; Aledda, R.; Alessi, E.; Allan, S.; Alves, D.; Ambrosino, R.; Amicucci, L.; Anand, H.; Anastassiou, G.; Andrèbe, Y.; Angioni, C.; Apruzzese, G.; Ariola, M.; Arnichand, H.; Arter, W.; Baciero, A.; Barnes, M.; Barrera, L.; Behn, R.; Bencze, A.; Bernardo, J.; Bernert, M.; Bettini, P.; Bilková, P.; Bin, W.; Birkenmeier, G.; Bizarro, J. P. S.; Blanchard, P.; Blanken, T.; Bluteau, M.; Bobkov, V.; Bogar, O.; Böhm, P.; Bolzonella, T.; Boncagni, L.; Botrugno, A.; Bottereau, C.; Bouquey, F.; Bourdelle, C.; Brémond, S.; Brezinsek, S.; Brida, D.; Brochard, F.; Buchanan, J.; Bufferand, H.; Buratti, P.; Cahyna, P.; Calabrò, G.; Camenen, Y.; Caniello, R.; Cannas, B.; Canton, A.; Cardinali, A.; Carnevale, D.; Carr, M.; Carralero, D.; Carvalho, P.; Casali, L.; Castaldo, C.; Castejón, F.; Castro, R.; Causa, F.; Cavazzana, R.; Cavedon, M.; Cecconello, M.; Ceccuzzi, S.; Cesario, R.; Challis, C. D.; Chapman, I. T.; Chapman, S.; Chernyshova, M.; Choi, D.; Cianfarani, C.; Ciraolo, G.; Citrin, J.; Clairet, F.; Classen, I.; Coelho, R.; Coenen, J. W.; Colas, L.; Conway, G.; Corre, Y.; Costea, S.; Crisanti, F.; Cruz, N.; Cseh, G.; Czarnecka, A.; D'Arcangelo, O.; De Angeli, M.; De Masi, G.; De Temmerman, G.; De Tommasi, G.; Decker, J.; Delogu, R. S.; Dendy, R.; Denner, P.; Di Troia, C.; Dimitrova, M.; D'Inca, R.; Dorić, V.; Douai, D.; Drenik, A.; Dudson, B.; Dunai, D.; Dunne, M.; Duval, B. P.; Easy, L.; Elmore, S.; Erdös, B.; Esposito, B.; Fable, E.; Faitsch, M.; Fanni, A.; Fedorczak, N.; Felici, F.; Ferreira, J.; Février, O.; Ficker, O.; Fietz, S.; Figini, L.; Figueiredo, A.; Fil, A.; Fishpool, G.; Fitzgerald, M.; Fontana, M.; Ford, O.; Frassinetti, L.; Fridström, R.; Frigione, D.; Fuchert, G.; Fuchs, C.; Furno Palumbo, M.; Futatani, S.; Gabellieri, L.; Gałązka, K.; Galdon-Quiroga, J.; Galeani, S.; Gallart, D.; Gallo, A.; Galperti, C.; Gao, Y.; Garavaglia, S.; Garcia, J.; Garcia-Carrasco, A.; Garcia-Lopez, J.; Garcia-Munoz, M.; Gardarein, J.-L.; Garzotti, L.; Gaspar, J.; Gauthier, E.; Geelen, P.; Geiger, B.; Ghendrih, P.; Ghezzi, F.; Giacomelli, L.; Giannone, L.; Giovannozzi, E.; Giroud, C.; Gleason González, C.; Gobbin, M.; Goodman, T. P.; Gorini, G.; Gospodarczyk, M.; Granucci, G.; Gruber, M.; Gude, A.; Guimarais, L.; Guirlet, R.; Gunn, J.; Hacek, P.; Hacquin, S.; Hall, S.; Ham, C.; Happel, T.; Harrison, J.; Harting, D.; Hauer, V.; Havlickova, E.; Hellsten, T.; Helou, W.; Henderson, S.; Hennequin, P.; Heyn, M.; Hnat, B.; Hölzl, M.; Hogeweij, D.; Honoré, C.; Hopf, C.; Horáček, J.; Hornung, G.; Horváth, L.; Huang, Z.; Huber, A.; Igitkhanov, J.; Igochine, V.; Imrisek, M.; Innocente, P.; Ionita-Schrittwieser, C.; Isliker, H.; Ivanova-Stanik, I.; Jacobsen, A. S.; Jacquet, P.; Jakubowski, M.; Jardin, A.; Jaulmes, F.; Jenko, F.; Jensen, T.; Jeppe Miki Busk, O.; Jessen, M.; Joffrin, E.; Jones, O.; Jonsson, T.; Kallenbach, A.; Kallinikos, N.; Kálvin, S.; Kappatou, A.; Karhunen, J.; Karpushov, A.; Kasilov, S.; Kasprowicz, G.; Kendl, A.; Kernbichler, W.; Kim, D.; Kirk, A.; Kjer, S.; Klimek, I.; Kocsis, G.; Kogut, D.; Komm, M.; Korsholm, S. B.; Koslowski, H. R.; Koubiti, M.; Kovacic, J.; Kovarik, K.; Krawczyk, N.; Krbec, J.; Krieger, K.; Krivska, A.; Kube, R.; Kudlacek, O.; Kurki-Suonio, T.; Labit, B.; Laggner, F. M.; Laguardia, L.; Lahtinen, A.; Lalousis, P.; Lang, P.; Lauber, P.; Lazányi, N.; Lazaros, A.; Le, H. B.; Lebschy, A.; Leddy, J.; Lefévre, L.; Lehnen, M.; Leipold, F.; Lessig, A.; Leyland, M.; Li, L.; Liang, Y.; Lipschultz, B.; Liu, Y. Q.; Loarer, T.; Loarte, A.; Loewenhoff, T.; Lomanowski, B.; Loschiavo, V. P.; Lunt, T.; Lupelli, I.; Lux, H.; Lyssoivan, A.; Madsen, J.; Maget, P.; Maggi, C.; Maggiora, R.; Magnussen, M. L.; Mailloux, J.; Maljaars, B.; Malygin, A.; Mantica, P.; Mantsinen, M.; Maraschek, M.; Marchand, B.; Marconato, N.; Marini, C.; Marinucci, M.; Markovic, T.; Marocco, D.; Marrelli, L.; Martin, Y.; Solis, J. R. Martin; Martitsch, A.; Mastrostefano, S.; Mattei, M.; Matthews, G.; Mavridis, M.; Mayoral, M.-L.; Mazon, D.; McCarthy, P.; McAdams, R.; McArdle, G.; McCarthy, P.; McClements, K.; McDermott, R.; McMillan, B.; Meisl, G.; Merle, A.; Meyer, O.; Milanesio, D.; Militello, F.; Miron, I. G.; Mitosinkova, K.; Mlynar, J.; Mlynek, A.; Molina, D.; Molina, P.; Monakhov, I.; Morales, J.; Moreau, D.; Morel, P.; Moret, J.-M.; Moro, A.; Moulton, D.; Müller, H. W.; Nabais, F.; Nardon, E.; Naulin, V.; Nemes-Czopf, A.; Nespoli, F.; Neu, R.; Nielsen, A. H.; Nielsen, S. K.; Nikolaeva, V.; Nimb, S.; Nocente, M.; Nouailletas, R.; Nowak, S.; Oberkofler, M.; Oberparleiter, M.; Ochoukov, R.; Odstrčil, T.; Olsen, J.; Omotani, J.; O'Mullane, M. G.; Orain, F.; Osterman, N.; Paccagnella, R.; Pamela, S.; Pangione, L.; Panjan, M.; Papp, G.; Papřok, R.; Parail, V.; Parra, F. I.; Pau, A.; Pautasso, G.; Pehkonen, S.-P.; Pereira, A.; Perelli Cippo, E.; Pericoli Ridolfini, V.; Peterka, M.; Petersson, P.; Petrzilka, V.; Piovesan, P.; Piron, C.; Pironti, A.; Pisano, F.; Pisokas, T.; Pitts, R.; Ploumistakis, I.; Plyusnin, V.; Pokol, G.; Poljak, D.; Pölöskei, P.; Popovic, Z.; Pór, G.; Porte, L.; Potzel, S.; Predebon, I.; Preynas, M.; Primc, G.; Pucella, G.; Puiatti, M. E.; Pütterich, T.; Rack, M.; Ramogida, G.; Rapson, C.; Rasmussen, J. Juul; Rasmussen, J.; Rattá, G. A.; Ratynskaia, S.; Ravera, G.; Réfy, D.; Reich, M.; Reimerdes, H.; Reimold, F.; Reinke, M.; Reiser, D.; Resnik, M.; Reux, C.; Ripamonti, D.; Rittich, D.; Riva, G.; Rodriguez-Ramos, M.; Rohde, V.; Rosato, J.; Ryter, F.; Saarelma, S.; Sabot, R.; Saint-Laurent, F.; Salewski, M.; Salmi, A.; Samaddar, D.; Sanchis-Sanchez, L.; Santos, J.; Sauter, O.; Scannell, R.; Scheffer, M.; Schneider, M.; Schneider, B.; Schneider, P.; Schneller, M.; Schrittwieser, R.; Schubert, M.; Schweinzer, J.; Seidl, J.; Sertoli, M.; Šesnić, S.; Shabbir, A.; Shalpegin, A.; Shanahan, B.; Sharapov, S.; Sheikh, U.; Sias, G.; Sieglin, B.; Silva, C.; Silva, A.; Silva Fuglister, M.; Simpson, J.; Snicker, A.; Sommariva, C.; Sozzi, C.; Spagnolo, S.; Spizzo, G.; Spolaore, M.; Stange, T.; Stejner Pedersen, M.; Stepanov, I.; Stober, J.; Strand, P.; Šušnjara, A.; Suttrop, W.; Szepesi, T.; Tál, B.; Tala, T.; Tamain, P.; Tardini, G.; Tardocchi, M.; Teplukhina, A.; Terranova, D.; Testa, D.; Theiler, C.; Thornton, A.; Tolias, P.; Tophøj, L.; Treutterer, W.; Trevisan, G. L.; Tripsky, M.; Tsironis, C.; Tsui, C.; Tudisco, O.; Uccello, A.; Urban, J.; Valisa, M.; Vallejos, P.; Valovic, M.; Van den Brand, H.; Vanovac, B.; Varoutis, S.; Vartanian, S.; Vega, J.; Verdoolaege, G.; Verhaegh, K.; Vermare, L.; Vianello, N.; Vicente, J.; Viezzer, E.; Vignitchouk, L.; Vijvers, W. A. J.; Villone, F.; Viola, B.; Vlahos, L.; Voitsekhovitch, I.; Vondráček, P.; Vu, N. M. T.; Wagner, D.; Walkden, N.; Wang, N.; Wauters, T.; Weiland, M.; Weinzettl, V.; Westerhof, E.; Wiesenberger, M.; Willensdorfer, M.; Wischmeier, M.; Wodniak, I.; Wolfrum, E.; Yadykin, D.; Zagórski, R.; Zammuto, I.; Zanca, P.; Zaplotnik, R.; Zestanakis, P.; Zhang, W.; Zoletnik, S.; Zuin, M.; ASDEX Upgrade, the; MAST; TCV Teams

2017-10-01

Integrating the plasma core performance with an edge and scrape-off layer (SOL) that leads to tolerable heat and particle loads on the wall is a major challenge. The new European medium size tokamak task force (EU-MST) coordinates research on ASDEX Upgrade (AUG), MAST and TCV. This multi-machine approach within EU-MST, covering a wide parameter range, is instrumental to progress in the field, as ITER and DEMO core/pedestal and SOL parameters are not achievable simultaneously in present day devices. A two prong approach is adopted. On the one hand, scenarios with tolerable transient heat and particle loads, including active edge localised mode (ELM) control are developed. On the other hand, divertor solutions including advanced magnetic configurations are studied. Considerable progress has been made on both approaches, in particular in the fields of: ELM control with resonant magnetic perturbations (RMP), small ELM regimes, detachment onset and control, as well as filamentary scrape-off-layer transport. For example full ELM suppression has now been achieved on AUG at low collisionality with n  =  2 RMP maintaining good confinement {{H}\\text{H≤ft(98,\\text{y}2\\right)}}≈ 0.95 . Advances have been made with respect to detachment onset and control. Studies in advanced divertor configurations (Snowflake, Super-X and X-point target divertor) shed new light on SOL physics. Cross field filamentary transport has been characterised in a wide parameter regime on AUG, MAST and TCV progressing the theoretical and experimental understanding crucial for predicting first wall loads in ITER and DEMO. Conditions in the SOL also play a crucial role for ELM stability and access to small ELM regimes. In the future we will refer to the author list of the paper as the EUROfusion MST1 Team.

Force fields of charged particles in micro-nanofluidic preconcentration systems

NASA Astrophysics Data System (ADS)

Gong, Lingyan; Ouyang, Wei; Li, Zirui; Han, Jongyoon

2017-12-01

Electrokinetic concentration devices based on the ion concentration polarization (ICP) phenomenon have drawn much attention due to their simple setup, high enrichment factor, and easy integration with many subsequent processes, such as separation, reaction, and extraction etc. Despite significant progress in the experimental research, fundamental understanding and detailed modeling of the preconcentration systems is still lacking. The mechanism of the electrokinetic trapping of charged particles is currently limited to the force balance analysis between the electric force and fluid drag force in an over-simplified one-dimensional (1D) model, which misses many signatures of the actual system. This letter studies the particle trapping phenomena that are not explainable in the 1D model through the calculation of the two-dimensional (2D) force fields. The trapping of charged particles is shown to significantly distort the electric field and fluid flow pattern, which in turn leads to the different trapping behaviors of particles of different sizes. The mechanisms behind the protrusions and instability of the focused band, which are important factors determining overall preconcentration efficiency, are revealed through analyzing the rotating fluxes of particles in the vicinity of the ion-selective membrane. The differences in the enrichment factors of differently sized particles are understood through the interplay between the electric force and convective fluid flow. These results provide insights into the electrokinetic concentration effect, which could facilitate the design and optimization of ICP-based preconcentration systems.

Role of Exposure Atmospheres on Particle Coarsening and Phase Transformation of LiAlO 2

DOE PAGES

Heo, Su Jeong; Hu, Boxun; Uddin, Md Aman; ...

2017-05-05

The phase transformation and particle coarsening of lithium aluminate (α-LiAlO 2) in electrolyte are the major causes of degradation affecting the performance and the lifetime of the molten carbonate fuel cell (MCFC). The stability of LiAlO 2 has been studied in Li 2CO 3-Na 2CO 3 electrolyte under accelerated conditions in reducing and oxidizing gas atmospheres at temperatures of 650 and 750 for up to 500 hours. X-ray diffraction analyses show that the progressive transformation of α-LiAlO 2 to γ-LiAlO 2 phase proceeds with increasing temperature in lower P CO2 and lower P O2 environments. Spherical LiAlO 2 particles weremore » transformed to coarsened pyramid-shape particles in 4% H 2-3% H 2O-N 2 and 100% N 2 (~10 ppm P O2 ) atmospheres. Under CO 2-rich atmospheres (4% H 2-30% CO 2-N 2 and 70% air-30% CO 2), both phase and particle size remained unchanged at 650 and 750ºC. The selected area electron diffraction (SAED) pattern analysis indicated that the large pyramidal shape particles (~30 μm) were γ-LiAlO 2 phase. Experimental observations and related simulation results pertaining to particle coarsening and phase transformation behavior of LiAlO 2 are presented.« less

Mechanical particle coating using polymethacrylate nanoparticle agglomerates for the preparation of controlled release fine particles: The relationship between coating performance and the characteristics of various polymethacrylates.

PubMed

Kondo, Keita; Kato, Shinsuke; Niwa, Toshiyuki

2017-10-30

We aimed to understand the factors controlling mechanical particle coating using polymethacrylate. The relationship between coating performance and the characteristics of polymethacrylate powders was investigated. First, theophylline crystals were treated using a mechanical powder processor to obtain theophylline spheres (<100μm). Second, five polymethacrylate latexes were powdered by spray freeze drying to produce colloidal agglomerates. Finally, mechanical particle coating was performed by mixing theophylline spheres and polymethacrylate agglomerates using the processor. The agglomerates were broken under mechanical stress to coat the spheres effectively. The coating performance of polymethacrylate agglomerates tended to increase as their pulverization progressed. Differences in the grindability of the agglomerates were attributed to differences in particle structure, resulting from consolidation between colloidal particles. High-grindability agglomerates exhibited higher pulverization as their glass transition temperature (T g ) increased and the further pulverization promoted coating. We therefore conclude that the minimization of polymethacrylate powder by pulverization is an important factor in mechanical particle coating using polymethacrylate with low deformability. Meanwhile, when product temperature during coating approaches T g of polymer, polymethacrylate was soften to show high coating performance by plastic deformation. The effective coating by this mechanism may be accomplished by adjusting the temperature in the processor to the T g . Copyright © 2017 Elsevier B.V. All rights reserved.

Induction of Micronuclei in Human Fibroblasts across the Bragg Curve of Energetic Si and Fe Ions

NASA Technical Reports Server (NTRS)

Wu, H.; Rusek, A.; Hada, M.

2006-01-01

The space environment consists of a varying field of radiation particles including high-energy ions, with spacecraft shielding material providing the major protection to astronauts from harmful exposure. Unlike low-LET gamma or X-rays, the presence of shielding does not always reduce the radiation risks for energetic charged particle exposure. Since the dose delivered by the charged particle increases sharply as the particle approaches the end of its range, a position known as the Bragg peak, the Bragg curve does not necessarily represent the biological damage along the particle traversal since biological effects are influenced by the track structure of both primary and secondary particles. Therefore, the biological Bragg curve is dependent on the energy and the type of the primary particle, and may vary for different biological endpoints. We studied micronuclei (MN) induction across the Bragg curve of Si and Fe ions at incident energies of 300 MeV/nucleon and 1 GeV/nucleon. A quantitative biological response curve did not reveal an increased yield of MN at the location of the Bragg peak. However, the ratio of mono- to bi-nucleated cells, which indicates inhibition in cell progression, increased at the Bragg peak location. These results confirm the hypothesis that severely damaged cells at the Bragg peak are likely to go through reproduction death.

Characteristics of storm runoff and sediment dispersal in the San Pedro Channel, southern California.

PubMed

Ahn, J H; Grant, S B

2007-01-01

In-site measurements of particle size spectra were obtained from three offshore cruises to evaluate the physical consequences of increased sediment transport and deposition offshore which was caused by episodic storm runoff water from the Santa Ana River watershed, a highly urbanised coastal watershed in southern California. Of the total annual runoff discharge to the coastal ocean, 89.2% occurred in the 2003/2004 winter season, and 0.22 Mt of sediment mass was transported during the storm events. The runoff plume at surface taken offshore by cross-shore currents progressed rapid aggregation and sedimentation, while the initially high concentration of suspended sediment discharged from the river outlet was dominated by small particles. Vertical profiles of particle size spectra revealed two separated plumes near the river outlet and turbidity plume along the bottom consisted of an abundance of very fine and dense particles. It would appear to support the theory that even if the storm runoff does not carry a high concentration of sediment being capable of generating negative buoyancy, sediment deposition on the shelf might mobilise in dense, fluid mud transported offshore by gravity. In a coastal pollution context, sediment particle size spectra information may offer potentially useful means of characterising particle-associated pollutants for purposes of source tracking and environmental interpretation.

A biologically inspired two-species exclusion model: effects of RNA polymerase motor traffic on simultaneous DNA replication

NASA Astrophysics Data System (ADS)

Ghosh, Soumendu; Mishra, Bhavya; Patra, Shubhadeep; Schadschneider, Andreas; Chowdhury, Debashish

2018-04-01

We introduce a two-species exclusion model to describe the key features of the conflict between the RNA polymerase (RNAP) motor traffic, engaged in the transcription of a segment of DNA, concomitant with the progress of two DNA replication forks on the same DNA segment. One of the species of particles (P) represents RNAP motors while the other (R) represents the replication forks. Motivated by the biological phenomena that this model is intended to capture, a maximum of two R particles only are allowed to enter the lattice from two opposite ends whereas the unrestricted number of P particles constitutes a totally asymmetric simple exclusion process (TASEP) in a segment in the middle of the lattice. The model captures three distinct pathways for resolving the co-directional as well as head-on collision between the P and R particles. Using Monte Carlo simulations and heuristic analytical arguments that combine exact results for the TASEP with mean-field approximations, we predict the possible outcomes of the conflict between the traffic of RNAP motors (P particles engaged in transcription) and the replication forks (R particles). In principle, the model can be adapted to experimental conditions to account for the data quantitatively.

Particle and Blood Cell Dynamics in Oscillatory Flows Final Report

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

Juan M. Restrepo

2008-09-01

Our aim has been to uncover fundamental aspects of the suspension and dislodgement of particles in wall-bounded oscillatory flows, in flows characterized by Reynolds numbers en- compassing the situation found in rivers and near shores (and perhaps in some industrial processes). Our research tools are computational and our coverage of parameter space fairly broad. Computational means circumvent many complications that make the measurement of the dynamics of particles in a laboratory setting an impractical task, especially on the broad range of parameter space we plan to report upon. The impact of this work on the geophysical problem of sedimentation ismore » boosted considerably by the fact that the proposed calculations can be considered ab-initio, in the sense that little to no modeling is done in generating dynamics of the particles and of the moving fluid: we use a three-dimensional Navier Stokes solver along with straightforward boundry conditions. Hence, to the extent that Navier Stokes is a model for an ideal incompressible isotropic Newtonian fluid, the calculations yield benchmark values for such things as the drag, buoyancy, and lift of particles, in a highly controlled environment. Our approach will be to make measurements of the lift, drag, and buoyancy of particles, by considering progressively more complex physical configurations and physics.« less

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

Heo, Su Jeong; Hu, Boxun; Uddin, Md Aman

The phase transformation and particle coarsening of lithium aluminate (α-LiAlO 2) in electrolyte are the major causes of degradation affecting the performance and the lifetime of the molten carbonate fuel cell (MCFC). The stability of LiAlO 2 has been studied in Li 2CO 3-Na 2CO 3 electrolyte under accelerated conditions in reducing and oxidizing gas atmospheres at temperatures of 650 and 750 for up to 500 hours. X-ray diffraction analyses show that the progressive transformation of α-LiAlO 2 to γ-LiAlO 2 phase proceeds with increasing temperature in lower P CO2 and lower P O2 environments. Spherical LiAlO 2 particles weremore » transformed to coarsened pyramid-shape particles in 4% H 2-3% H 2O-N 2 and 100% N 2 (~10 ppm P O2 ) atmospheres. Under CO 2-rich atmospheres (4% H 2-30% CO 2-N 2 and 70% air-30% CO 2), both phase and particle size remained unchanged at 650 and 750ºC. The selected area electron diffraction (SAED) pattern analysis indicated that the large pyramidal shape particles (~30 μm) were γ-LiAlO 2 phase. Experimental observations and related simulation results pertaining to particle coarsening and phase transformation behavior of LiAlO 2 are presented.« less

Particle-in-cell simulations on graphic processing units

NASA Astrophysics Data System (ADS)

Ren, C.; Zhou, X.; Li, J.; Huang, M. C.; Zhao, Y.

2014-10-01

We will show our recent progress in using GPU's to accelerate the PIC code OSIRIS [Fonseca et al. LNCS 2331, 342 (2002)]. The OISRIS parallel structure is retained and the computation-intensive kernels are shipped to GPU's. Algorithms for the kernels are adapted for the GPU, including high-order charge-conserving current deposition schemes with few branching and parallel particle sorting [Kong et al., JCP 230, 1676 (2011)]. These algorithms make efficient use of the GPU shared memory. This work was supported by U.S. Department of Energy under Grant No. DE-FC02-04ER54789 and by NSF under Grant No. PHY-1314734.

Recent Progress on Understanding SEP Acceleration and Transport

NASA Astrophysics Data System (ADS)

Cohen, C.

2017-12-01

Joint observations between near-Earth spacecraft and the twin STEREO spacecraft have allowed new examinations of the longitudinal extent of solar energetic particles (SEPs). Although the radial dependence will not be measured in detail until Parker Solar Probe and Solar Orbiter have launched, recent developments in modeling SEP acceleration and transport have revealed interesting dependences on magnetic field configurations and the characteristics of seed particle populations. This talk will review recent SEP in-situ observations along with theoretical studies and their implications for our understanding of SEP acceleration and transport in the inner heliosphere and our expectations for upcoming Solar Orbiter and Parker Solar Probe observations.

Progress on the Multiphysics Capabilities of the Parallel Electromagnetic ACE3P Simulation Suite

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

Kononenko, Oleksiy

2015-03-26

ACE3P is a 3D parallel simulation suite that is being developed at SLAC National Accelerator Laboratory. Effectively utilizing supercomputer resources, ACE3P has become a key tool for the coupled electromagnetic, thermal and mechanical research and design of particle accelerators. Based on the existing finite-element infrastructure, a massively parallel eigensolver is developed for modal analysis of mechanical structures. It complements a set of the multiphysics tools in ACE3P and, in particular, can be used for the comprehensive study of microphonics in accelerating cavities ensuring the operational reliability of a particle accelerator.

Development progress of the Materials Analysis and Particle Probe

NASA Astrophysics Data System (ADS)

Lucia, M.; Kaita, R.; Majeski, R.; Bedoya, F.; Allain, J. P.; Boyle, D. P.; Schmitt, J. C.; Onge, D. A. St.

2014-11-01

The Materials Analysis and Particle Probe (MAPP) is a compact in vacuo surface science diagnostic, designed to provide in situ surface characterization of plasma facing components in a tokamak environment. MAPP has been implemented for operation on the Lithium Tokamak Experiment at Princeton Plasma Physics Laboratory (PPPL), where all control and analysis systems are currently under development for full remote operation. Control systems include vacuum management, instrument power, and translational/rotational probe drive. Analysis systems include onboard Langmuir probes and all components required for x-ray photoelectron spectroscopy, low-energy ion scattering spectroscopy, direct recoil spectroscopy, and thermal desorption spectroscopy surface analysis techniques.

Development progress of the Materials Analysis and Particle Probe.

PubMed

Lucia, M; Kaita, R; Majeski, R; Bedoya, F; Allain, J P; Boyle, D P; Schmitt, J C; Onge, D A St

2014-11-01

The Materials Analysis and Particle Probe (MAPP) is a compact in vacuo surface science diagnostic, designed to provide in situ surface characterization of plasma facing components in a tokamak environment. MAPP has been implemented for operation on the Lithium Tokamak Experiment at Princeton Plasma Physics Laboratory (PPPL), where all control and analysis systems are currently under development for full remote operation. Control systems include vacuum management, instrument power, and translational/rotational probe drive. Analysis systems include onboard Langmuir probes and all components required for x-ray photoelectron spectroscopy, low-energy ion scattering spectroscopy, direct recoil spectroscopy, and thermal desorption spectroscopy surface analysis techniques.

Mechanical trapping of particles in granular media

NASA Astrophysics Data System (ADS)

Kerimov, Abdulla; Mavko, Gary; Mukerji, Tapan; Al Ibrahim, Mustafa A.

2018-02-01

Mechanical trapping of fine particles in the pores of granular materials is an essential mechanism in a wide variety of natural and industrial filtration processes. The progress of invading particles is primarily limited by the network of pore throats and connected pathways encountered by the particles during their motion through the porous medium. Trapping of invading particles is limited to a depth defined by the size, shape, and distribution of the invading particles with respect to the size, shape, and distribution of the host porous matrix. Therefore, the trapping process, in principle, can be used to obtain information about geometrical properties, such as pore throat and particle size, of the underlying host matrix. A numerical framework is developed to simulate the mechanical trapping of fine particles in porous granular media with prescribed host particle size, shape, and distribution. The trapping of invading particles is systematically modeled in host packings with different host particle distributions: monodisperse, bidisperse, and polydisperse distributions of host particle sizes. Our simulation results show quantitatively and qualitatively to what extent trapping behavior is different in the generated monodisperse, bidisperse, and polydisperse packings of spherical particles. Depending on host particle size and distribution, the information about extreme estimates of minimal pore throat sizes of the connected pathways in the underlying host matrix can be inferred from trapping features, such as the fraction of trapped particles as a function of invading particle size. The presence of connected pathways with minimum and maximum of minimal pore throat diameters can be directly obtained from trapping features. This limited information about the extreme estimates of pore throat sizes of the connected pathways in the host granular media inferred from our numerical simulations is consistent with simple geometrical estimates of extreme value of pore and throat sizes of the densest structural arrangements of spherical particles and geometrical Delaunay tessellation analysis of the pore space of host granular media. Our results suggest simple relations between the host particle size and trapping features. These relationships can be potentially used to describe both the dynamics of the mechanical trapping process and the geometrical properties of the host granular media.

Mechanical trapping of particles in granular media.

PubMed

Kerimov, Abdulla; Mavko, Gary; Mukerji, Tapan; Al Ibrahim, Mustafa A

2018-02-01

Mechanical trapping of fine particles in the pores of granular materials is an essential mechanism in a wide variety of natural and industrial filtration processes. The progress of invading particles is primarily limited by the network of pore throats and connected pathways encountered by the particles during their motion through the porous medium. Trapping of invading particles is limited to a depth defined by the size, shape, and distribution of the invading particles with respect to the size, shape, and distribution of the host porous matrix. Therefore, the trapping process, in principle, can be used to obtain information about geometrical properties, such as pore throat and particle size, of the underlying host matrix. A numerical framework is developed to simulate the mechanical trapping of fine particles in porous granular media with prescribed host particle size, shape, and distribution. The trapping of invading particles is systematically modeled in host packings with different host particle distributions: monodisperse, bidisperse, and polydisperse distributions of host particle sizes. Our simulation results show quantitatively and qualitatively to what extent trapping behavior is different in the generated monodisperse, bidisperse, and polydisperse packings of spherical particles. Depending on host particle size and distribution, the information about extreme estimates of minimal pore throat sizes of the connected pathways in the underlying host matrix can be inferred from trapping features, such as the fraction of trapped particles as a function of invading particle size. The presence of connected pathways with minimum and maximum of minimal pore throat diameters can be directly obtained from trapping features. This limited information about the extreme estimates of pore throat sizes of the connected pathways in the host granular media inferred from our numerical simulations is consistent with simple geometrical estimates of extreme value of pore and throat sizes of the densest structural arrangements of spherical particles and geometrical Delaunay tessellation analysis of the pore space of host granular media. Our results suggest simple relations between the host particle size and trapping features. These relationships can be potentially used to describe both the dynamics of the mechanical trapping process and the geometrical properties of the host granular media.

Biomimetics: reconstitution of low-density lipoprotein for targeted drug delivery and related theranostic applications.

PubMed

Zhu, Chunlei; Xia, Younan

2017-12-11

Low-density lipoprotein (LDL), one of the four major groups of lipoproteins for lipid transport in vivo, is emerging as an attractive carrier for the targeted delivery of theranostic agents. In contrast to the synthetic systems, LDL particles are intrinsically biocompatible and biodegradable, together with reduced immunogenicity and natural capabilities to target cancerous cells and to escape from the recognition and elimination by the reticuloendothelial system. Enticed by these attributes, a number of strategies have been developed for reconstituting LDL particles, including conjugation to the apolipoprotein, insertion into the phospholipid layer, and loading into the core. Here we present a tutorial review on the development of reconstituted LDL (rLDL) particles for theranostic applications. We start with a brief introduction to LDL and LDL receptor, as well as the advantages of using rLDL particles as a natural and versatile platform for the targeted delivery of theranostic agents. After a discussion of commonly used strategies for the reconstitution of LDL, we highlight the applications of rLDL particles in the staging of disease progression, treatment of lesioned tissues, and delivery of photosensitizers for photodynamic cancer therapy. We finish this review with a perspective on the remaining challenges and future directions.

Charged Particle Therapy Steps Into the Clinical Environment

NASA Astrophysics Data System (ADS)

Haberer, Th.

Beams of heavy charged particles like protons or carbon ions represent the ideal tool for the treatment of deep-seated, inoperable and radioresistant tumors. For more than 4 decades research with beams of charged particles has been performed. In total more than 40000 patients have been treated, mostly using protons being delivered by accelerators that were designed for basic research centers. In Berkeley, USA heavier particles like helium or neon ions were used to conduct clinical trials until 1992. Based on that somewhat limited technological standard and triggered by the promising results from Berkeley the first dedicated charged particle facilities were constructed. In order to maximally exploit the advantageous physical and radiobiological characteristics of these beams enormous effort was put into developing dynamic beam delivery techniques and tailoring the capabilities of the accelerators, the planning systems and the quality assurance procedures and equipment to the requirements resulting from these new treatment modalities. Active beam delivery systems integrated in rotating gantries, if necessary, will allow the production of superior dose distributions that precisely follow the medical prescription. The technological progress being made during the last 10 years defines the state of the art of the upcoming next-generation facilities for the clinical environment in Europe and Japan.

A PILOT INVESTIGATION OF THE RELATIVE TOXICITY OF INDOOR AND OUTDOOR FINE PARTICLES: IN-VITRO EFFECTS OF ENDOTOXIN AND OTHER PARTICULATE PROPERTIES. (R827353C003)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

A PILOT INVESTIGATION OF THE RELATIVE TOXICITY OF INDOOR AND OUTDOOR FINE PARTICLES: IN-VITRO EFFECTS OF ENDOTOXIN AND OTHER PARTICULATE PROPERTIES. (R827353C001)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Acute High-level Exposure to WTC Particles Alters Expression of Genes Associated with Oxidative Stress and Immune Function in the Lung

EPA Science Inventory

Abstract First responders (FR) present at Ground Zero in the first 72 h after the World Trade Center (WTC) collapsed have progressively exhibited significant respiratory injuries. The few toxicology studies performed to date evaluated effects from just fine(< 2.5 um) WTC dusts; n...

Coherent soft X-ray diffraction imaging of coliphage PR772 at the Linac coherent light source

PubMed Central

Reddy, Hemanth K.N.; Yoon, Chun Hong; Aquila, Andrew; Awel, Salah; Ayyer, Kartik; Barty, Anton; Berntsen, Peter; Bielecki, Johan; Bobkov, Sergey; Bucher, Maximilian; Carini, Gabriella A.; Carron, Sebastian; Chapman, Henry; Daurer, Benedikt; DeMirci, Hasan; Ekeberg, Tomas; Fromme, Petra; Hajdu, Janos; Hanke, Max Felix; Hart, Philip; Hogue, Brenda G.; Hosseinizadeh, Ahmad; Kim, Yoonhee; Kirian, Richard A.; Kurta, Ruslan P.; Larsson, Daniel S.D.; Duane Loh, N.; Maia, Filipe R.N.C.; Mancuso, Adrian P.; Mühlig, Kerstin; Munke, Anna; Nam, Daewoong; Nettelblad, Carl; Ourmazd, Abbas; Rose, Max; Schwander, Peter; Seibert, Marvin; Sellberg, Jonas A.; Song, Changyong; Spence, John C.H.; Svenda, Martin; Van der Schot, Gijs; Vartanyants, Ivan A.; Williams, Garth J.; Xavier, P. Lourdu

2017-01-01

Single-particle diffraction from X-ray Free Electron Lasers offers the potential for molecular structure determination without the need for crystallization. In an effort to further develop the technique, we present a dataset of coherent soft X-ray diffraction images of Coliphage PR772 virus, collected at the Atomic Molecular Optics (AMO) beamline with pnCCD detectors in the LAMP instrument at the Linac Coherent Light Source. The diameter of PR772 ranges from 65–70 nm, which is considerably smaller than the previously reported ~600 nm diameter Mimivirus. This reflects continued progress in XFEL-based single-particle imaging towards the single molecular imaging regime. The data set contains significantly more single particle hits than collected in previous experiments, enabling the development of improved statistical analysis, reconstruction algorithms, and quantitative metrics to determine resolution and self-consistency. PMID:28654088

[Progress in heavy particle radiotherapy].

PubMed

Tsujii, H; Tsuji, H; Okumura, T

1994-06-01

In recent years, new types of ionizing radiations have been used as an attractive modality in cancer treatments. Low LET radiation such as protons and helium ions has the advantage of a high physical selectivity of irradiation. Clinical results have confirmed that they are of benefit in certain types of cancer. High LET particles such as fast neutrons, heavy ions (carbon, neon) and negative pions possess higher radiobiological effects (RBE). Moreover, the latter two particles have an advantage of improved dose distribution. The clinical indications for protons are those located in close vicinity to the critical normal organs, and those for fast neutrons are relatively superficial tumors. Further studies are needed to determine indications for pions. The available clinical experience in selected tumors with protons, pions and fast neutrons justifies the heavy-ion therapy programs. Successful results are anticipated from HIMAC (Heavy ion medical accelerator in Chiba) which is a dedicated facility for heavy-ion therapy.

Coronal and interplanetary propagation, interplanetary acceleration, cosmic-ray observations by deep space network and anomalous component

NASA Technical Reports Server (NTRS)

Ng, C. K.

1986-01-01

The purpose is to provide an overview of the contributions presented in sessions SH3, SH1.5, SH4.6 and SH4.7 of the 19th International Cosmic Ray Conference. These contributed papers indicate that steady progress continues to be made in both the observational and the theoretical aspects of the transport and acceleration of energetic charged particles in the heliosphere. Studies of solar and interplanetary particles have placed emphasis on particle directional distributions in relation to pitch-angle scattering and magnetic focusing, on the rigidity and spatial dependence of the mean free path, and on new propagation regimes in the inner and outer heliosphere. Coronal propagation appears in need of correlative multi-spacecraft studies in association with detailed observation of the flare process and coronal magnetic structures. Interplanetary acceleration has now gone into a consolidation phase, with theories being worked out in detail and checked against observation.

Coherent soft X-ray diffraction imaging of coliphage PR772 at the Linac coherent light source

DOE PAGES

Reddy, Hemanth K. N.; Yoon, Chun Hong; Aquila, Andrew; ...

2017-06-27

Single-particle diffraction from X-ray Free Electron Lasers offers the potential for molecular structure determination without the need for crystallization. In an effort to further develop the technique, we present a dataset of coherent soft X-ray diffraction images of Coliphage PR772 virus, collected at the Atomic Molecular Optics (AMO) beamline with pnCCD detectors in the LAMP instrument at the Linac Coherent Light Source. The diameter of PR772 ranges from 65–70 nm, which is considerably smaller than the previously reported ~600 nm diameter Mimivirus. This reflects continued progress in XFEL-based single-particle imaging towards the single molecular imaging regime. As a result, themore » data set contains significantly more single particle hits than collected in previous experiments, enabling the development of improved statistical analysis, reconstruction algorithms, and quantitative metrics to determine resolution and self-consistency.« less

The structure of evaporating and combusting sprays: Measurements and predictions

NASA Technical Reports Server (NTRS)

Shuen, J. S.; Solomon, A. S. P.; Faeth, G. M.

1982-01-01

An apparatus was constructed to provide measurements in open sprays with no zones of recirculation, in order to provide well-defined conditions for use in evaluating spray models. Measurements were completed in a gas jet, in order to test experimental methods, and are currently in progress for nonevaporating sprays. A locally homogeneous flow (LHF) model where interphase transport rates are assumed to be infinitely fast; a separated flow (SF) model which allows for finite interphase transport rates but neglects effects of turbulent fluctuations on drop motion; and a stochastic SF model which considers effects of turbulent fluctuations on drop motion were evaluated using existing data on particle-laden jets. The LHF model generally overestimates rates of particle dispersion while the SF model underestimates dispersion rates. The stochastic SF flow yield satisfactory predictions except at high particle mass loadings where effects of turbulence modulation may have caused the model to overestimate turbulence levels.

Disinfection of bacteria attached to granular activated carbon.

PubMed Central

LeChevallier, M W; Hassenauer, T S; Camper, A K; McFeters, G A

1984-01-01

Heterotrophic plate count bacteria, coliform organisms, and pathogenic microorganisms attached to granular activated carbon particles were examined for their susceptibility to chlorine disinfection. When these bacteria were grown on carbon particles and then disinfected with 2.0 mg of chlorine per liter (1.4 to 1.6 mg of free chlorine residual per liter after 1 h) for 1 h, no significant decrease in viable counts was observed. Washed cells attached to the surface of granular activated carbon particles showed similar resistance to chlorine, but a progressive increase in sublethal injury was found. Observations made by scanning electron microscope indicated that granular activated carbon was colonized by bacteria which grow in cracks and crevices and are coated by an extracellular slime layer. These data suggest a possible mechanism by which treatment and disinfection barriers can be penetrated and pathogenic bacteria may enter drinking water supplies. Images PMID:6508306

Recent advances in microparticle and nanoparticle delivery vehicles for mucosal vaccination.

PubMed

McNeela, E A; Lavelle, E C

2012-01-01

The great potential of mucosal vaccination is widely accepted but progress in the clinical development of subunit mucosal vaccines has been disappointing. Of the available approaches, the use of polymer-based microparticles is attractive because these delivery vehicles can be specifically tailored for vaccines and they offer the potential for integration of adjuvant. Here we address recent developments in the use of particulates as mucosal vaccines and the potential of novel targeting strategies, formulation approaches and adjuvant combinations to enhance the efficacy of particle-based mucosal vaccines. This review discusses the current status of mucosal vaccines based on particles and highlights several of the strategies that are currently under investigation for improving their immunogenicity. These include enhancing the stability of formulations in the luminal environment, increasing uptake by specifically targeting particles to mucosal inductive sites, and augmenting immunogenicity through co-formulation with immunostimulatory agents.

Reinventing the Accelerator for the High Energy Frontier

ScienceCinema

Rosenzweig, James [UCLA, Los Angeles, California, United States

2017-12-09

The history of discovery in high-energy physics has been intimately connected with progress in methods of accelerating particles for the past 75 years. This remains true today, as the post-LHC era in particle physics will require significant innovation and investment in a superconducting linear collider. The choice of the linear collider as the next-generation discovery machine, and the selection of superconducting technology has rather suddenly thrown promising competing techniques -- such as very large hadron colliders, muon colliders, and high-field, high frequency linear colliders -- into the background. We discuss the state of such conventional options, and the likelihood of their eventual success. We then follow with a much longer view: a survey of a new, burgeoning frontier in high energy accelerators, where intense lasers, charged particle beams, and plasmas are all combined in a cross-disciplinary effort to reinvent the accelerator from its fundamental principles on up.

Progress in understanding fission-product behaviour in coated uranium-dioxide fuel particles

NASA Astrophysics Data System (ADS)

Barrachin, M.; Dubourg, R.; Kissane, M. P.; Ozrin, V.

2009-03-01

Supported by results of calculations performed with two analytical tools (MFPR, which takes account of physical and chemical mechanisms in calculating the chemical forms and physical locations of fission products in UO2, and MEPHISTA, a thermodynamic database), this paper presents an investigation of some important aspects of the fuel microstructure and chemical evolutions of irradiated TRISO particles. The following main conclusions can be identified with respect to irradiated TRISO fuel: first, the relatively low oxygen potential within the fuel particles with respect to PWR fuel leads to chemical speciation that is not typical of PWR fuels, e.g., the relatively volatile behaviour of barium; secondly, the safety-critical fission-product caesium is released from the urania kernel but the buffer and pyrolytic-carbon coatings could form an important chemical barrier to further migration (i.e., formation of carbides). Finally, significant releases of fission gases from the urania kernel are expected even in nominal conditions.

Coherent soft X-ray diffraction imaging of coliphage PR772 at the Linac coherent light source.

PubMed

Reddy, Hemanth K N; Yoon, Chun Hong; Aquila, Andrew; Awel, Salah; Ayyer, Kartik; Barty, Anton; Berntsen, Peter; Bielecki, Johan; Bobkov, Sergey; Bucher, Maximilian; Carini, Gabriella A; Carron, Sebastian; Chapman, Henry; Daurer, Benedikt; DeMirci, Hasan; Ekeberg, Tomas; Fromme, Petra; Hajdu, Janos; Hanke, Max Felix; Hart, Philip; Hogue, Brenda G; Hosseinizadeh, Ahmad; Kim, Yoonhee; Kirian, Richard A; Kurta, Ruslan P; Larsson, Daniel S D; Duane Loh, N; Maia, Filipe R N C; Mancuso, Adrian P; Mühlig, Kerstin; Munke, Anna; Nam, Daewoong; Nettelblad, Carl; Ourmazd, Abbas; Rose, Max; Schwander, Peter; Seibert, Marvin; Sellberg, Jonas A; Song, Changyong; Spence, John C H; Svenda, Martin; Van der Schot, Gijs; Vartanyants, Ivan A; Williams, Garth J; Xavier, P Lourdu

2017-06-27

Single-particle diffraction from X-ray Free Electron Lasers offers the potential for molecular structure determination without the need for crystallization. In an effort to further develop the technique, we present a dataset of coherent soft X-ray diffraction images of Coliphage PR772 virus, collected at the Atomic Molecular Optics (AMO) beamline with pnCCD detectors in the LAMP instrument at the Linac Coherent Light Source. The diameter of PR772 ranges from 65-70 nm, which is considerably smaller than the previously reported ~600 nm diameter Mimivirus. This reflects continued progress in XFEL-based single-particle imaging towards the single molecular imaging regime. The data set contains significantly more single particle hits than collected in previous experiments, enabling the development of improved statistical analysis, reconstruction algorithms, and quantitative metrics to determine resolution and self-consistency.

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.

Forecasting of Radiation Belts: Results From the PROGRESS Project.

NASA Astrophysics Data System (ADS)

Balikhin, M. A.; Arber, T. D.; Ganushkina, N. Y.; Walker, S. N.

2017-12-01

Forecasting of Radiation Belts: Results from the PROGRESS Project. The overall goal of the PROGRESS project, funded in frame of EU Horizon2020 programme, is to combine first principles based models with the systems science methodologies to achieve reliable forecasts of the geo-space particle radiation environment.The PROGRESS incorporates three themes : The propagation of the solar wind to L1, Forecast of geomagnetic indices, and forecast of fluxes of energetic electrons within the magnetosphere. One of the important aspects of the PROGRESS project is the development of statistical wave models for magnetospheric waves that affect the dynamics of energetic electrons such as lower band chorus, hiss and equatorial noise. The error reduction ratio (ERR) concept has been used to optimise the set of solar wind and geomagnetic parameters for organisation of statistical wave models for these emissions. The resulting sets of parameters and statistical wave models will be presented and discussed. However the ERR analysis also indicates that the combination of solar wind and geomagnetic parameters accounts for only part of the variance of the emissions under investigation (lower band chorus, hiss and equatorial noise). In addition, advances in the forecast of fluxes of energetic electrons, exploiting empirical models and the first principles IMPTAM model achieved by the PROGRESS project is presented.

Lipid-Altering Therapies and the Progression of Atherosclerotic Disease

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

Wierzbicki, Anthony S.

2007-04-15

Lipids play a key role in the progression of atherosclerosis, and lipid-lowering therapies have been studied for 30 years in coronary disease. Measurement of the progression of atherosclerosis through carotid intima-media thickness, coronary mean lumen diameter, and, mostly recently, intravascular ultrasound is generally accepted. This article reviews the role of lipid-lowering therapies in changing the rate of atherosclerosis progression in the coronary and carotid circulations. Statins are the primary therapy used to reduce atherosclerosis and cardiovascular events, including strokes and transient ischemic attacks, and have benefits in reducing events in patients undergoing carotid endarterectomy. In contrast, data for other agents,more » including fibrates and nicotinic acid, in reducing the progression of atherosclerosis are less extensive and not as well known. There is increasing interest in optimizing the whole lipid profile, as this might deliver extra benefits over and above statin therapy alone. Initial proof of this concept has recently come from studies that measured the progression of atherosclerosis and showed that adding nicotinic acid to statin therapy and, more directly, infusion of high-density lipoprotein-like particles reduced progression and indeed might induce regression of the disease. It is likely that the management of significant carotid stenosis will become ever more drug focused and will be customized to the lipid profile of each patient with intervention reserved only for late-stage symptomatic disease.« less

The Phagocytosis and Toxicity of Amorphous Silica

PubMed Central

Costantini, Lindsey M.; Gilberti, Renée M.; Knecht, David A.

2011-01-01

Background Inhalation of crystalline silica is known to cause an inflammatory reaction and chronic exposure leads to lung fibrosis and can progress into the disease, silicosis. Cultured macrophages bind crystalline silica particles, phagocytose them, and rapidly undergo apoptotic and necrotic death. The mechanism by which particles are bound and internalized and the reason particles are toxic is unclear. Amorphous silica has been considered to be a less toxic form, but this view is controversial. We compared the uptake and toxicity of amorphous silica to crystalline silica. Methodology/Principal Findings Amorphous silica particles are phagocytosed by macrophage cells and a single internalized particle is capable of killing a cell. Fluorescent dextran is released from endo-lysosomes within two hours after silica treatment and Caspase-3 activation occurs within 4 hours. Interestingly, toxicity is specific to macrophage cell lines. Other cell types are resistant to silica particle toxicity even though they internalize the particles. The large and uniform size of the spherical, amorphous silica particles allowed us to monitor them during the uptake process. In mCherry-actin transfected macrophages, actin rings began to form 1-3 minutes after silica binding and the actin coat disassembled rapidly following particle internalization. Pre-loading cells with fluorescent dextran allowed us to visualize the fusion of phagosomes with endosomes during internalization. These markers provided two new ways to visualize and quantify particle internalization. At 37°C the rate of amorphous silica internalization was very rapid regardless of particle coating. However, at room temperature, opsonized silica is internalized much faster than non-opsonized silica. Conclusions/Significance Our results indicate that amorphous and crystalline silica are both phagocytosed and both toxic to mouse alveolar macrophage (MH-S) cells. The pathway leading to apoptosis appears to be similar in both cases. However, the result suggests a mechanistic difference between FcγRIIA receptor-mediated and non-opsonized silica particle phagocytosis. PMID:21311600

The phagocytosis and toxicity of amorphous silica.

PubMed

Costantini, Lindsey M; Gilberti, Renée M; Knecht, David A

2011-02-02

Inhalation of crystalline silica is known to cause an inflammatory reaction and chronic exposure leads to lung fibrosis and can progress into the disease, silicosis. Cultured macrophages bind crystalline silica particles, phagocytose them, and rapidly undergo apoptotic and necrotic death. The mechanism by which particles are bound and internalized and the reason particles are toxic is unclear. Amorphous silica has been considered to be a less toxic form, but this view is controversial. We compared the uptake and toxicity of amorphous silica to crystalline silica. Amorphous silica particles are phagocytosed by macrophage cells and a single internalized particle is capable of killing a cell. Fluorescent dextran is released from endo-lysosomes within two hours after silica treatment and Caspase-3 activation occurs within 4 hours. Interestingly, toxicity is specific to macrophage cell lines. Other cell types are resistant to silica particle toxicity even though they internalize the particles. The large and uniform size of the spherical, amorphous silica particles allowed us to monitor them during the uptake process. In mCherry-actin transfected macrophages, actin rings began to form 1-3 minutes after silica binding and the actin coat disassembled rapidly following particle internalization. Pre-loading cells with fluorescent dextran allowed us to visualize the fusion of phagosomes with endosomes during internalization. These markers provided two new ways to visualize and quantify particle internalization. At 37 °C the rate of amorphous silica internalization was very rapid regardless of particle coating. However, at room temperature, opsonized silica is internalized much faster than non-opsonized silica. Our results indicate that amorphous and crystalline silica are both phagocytosed and both toxic to mouse alveolar macrophage (MH-S) cells. The pathway leading to apoptosis appears to be similar in both cases. However, the result suggests a mechanistic difference between FcγRIIA receptor-mediated and non-opsonized silica particle phagocytosis.

A Two-Step Integrated Theory of Everything (TOE)

NASA Astrophysics Data System (ADS)

Colella, Antonio

2017-01-01

Two opposing TOE visions are my Two-Step (physics/math) and Hawking's single math step. My Two-Step should replace the single step because of the latter's near zero results after a century of attempts. My physics step had 3 goals. First ``Everything'' was defined as 20 interrelated amplified theories (e.g. string, Higgs forces, spontaneous symmetry breaking, particle decays, dark matter, dark energy, stellar black holes) and their intimate physical interrelationships. Amplifications of Higgs forces theory (e.g. matter particles and their associated Higgs forces were one and inseparable, spontaneous symmetry breaking was bidirectional and caused by high temperatures not Higgs forces, and sum of 8 Higgs forces of 8 permanent matter particles was dark energy) were key to my Two-Step TOE. The second goal answered all outstanding physics questions: what were Higgs forces, dark energy, dark matter, stellar black holes, our universe's creation, etc.? The third goal provided correct inputs for the two part second math step, an E8 Lie algebra for particles and an N-body cosmology simulation (work in progress). Scientific advancement occurs only if the two opposing TOEs are openly discussed/debated.

Collisions of unequal mass black holes and the point particle limit

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

Sperhake, Ulrich; CENTRA, Departamento de Fisica, Instituto Superior Tecnico, Universidade Tecnica de Lisboa - UTL, Av. Rovisco Pais 1, 1049 Lisboa; California Institute of Technology, Pasadena, California 91125

Numerical relativity has seen incredible progress in the last years, and is being applied with success to a variety of physical phenomena, from gravitational wave research and relativistic astrophysics to cosmology and high-energy physics. Here we probe the limits of current numerical setups, by studying collisions of unequal mass, nonrotating black holes of mass ratios up to 1 ratio 100 and making contact with a classical calculation in general relativity: the infall of a pointlike particle into a massive black hole. Our results agree well with the predictions coming from linearized calculations of the infall of pointlike particles into nonrotatingmore » black holes. In particular, in the limit that one hole is much smaller than the other, and the infall starts from an infinite initial separation, we recover the point-particle limit. Thus, numerical relativity is able to bridge the gap between fully nonlinear dynamics and linearized approximations, which may have important applications. Finally, we also comment on the 'spurious' radiation content in the initial data and the linearized predictions.« less

Hybrid Methods for Muon Accelerator Simulations with Ionization Cooling

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

Kunz, Josiah; Snopok, Pavel; Berz, Martin

Muon ionization cooling involves passing particles through solid or liquid absorbers. Careful simulations are required to design muon cooling channels. New features have been developed for inclusion in the transfer map code COSY Infinity to follow the distribution of charged particles through matter. To study the passage of muons through material, the transfer map approach alone is not sufficient. The interplay of beam optics and atomic processes must be studied by a hybrid transfer map--Monte-Carlo approach in which transfer map methods describe the deterministic behavior of the particles, and Monte-Carlo methods are used to provide corrections accounting for the stochasticmore » nature of scattering and straggling of particles. The advantage of the new approach is that the vast majority of the dynamics are represented by fast application of the high-order transfer map of an entire element and accumulated stochastic effects. The gains in speed are expected to simplify the optimization of cooling channels which is usually computationally demanding. Progress on the development of the required algorithms and their application to modeling muon ionization cooling channels is reported.« less

Particle protection capability of SEMI-compliant EUV-pod carriers

NASA Astrophysics Data System (ADS)

Huang, George; He, Long; Lystad, John; Kielbaso, Tom; Montgomery, Cecilia; Goodwin, Frank

2010-04-01

With the projected rollout of pre-production extreme ultraviolet lithography (EUVL) scanners in 2010, EUVL pilot line production will become a reality in wafer fabrication companies. Among EUVL infrastructure items that must be ready, EUV mask carriers remain critical. To keep non-pellicle EUV masks free from particle contamination, an EUV pod concept has been extensively studied. Early prototypes demonstrated nearly particle-free results at a 53 nm PSL equivalent inspection sensitivity during EUVL mask robotic handling, shipment, vacuum pump-purge, and storage. After the passage of SEMI E152, which specifies the EUV pod mechanical interfaces, standards-compliant EUV pod prototypes, including a production version inner pod and prototype outer pod, were built and tested. Their particle protection capability results are reported in this paper. A state-of-the-art blank defect inspection tool was used to quantify their defect protection capability during mask robotic handling, shipment, and storage tests. To ensure the availability of an EUV pod for 2010 pilot production, the progress and preliminary test results of pre-production EUV outer pods are reported as well.

Deep particle bed dryout model based on flooding

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

Kuan, P.

1987-01-01

Examination of the damaged Three Mile island Unit 2 (TMI-2) reactor indicates that a deep (approx. 1-m) bed of relatively large (approx. 1-mm) particles was formed in the core. Cooling of such beds is crucial to the arrest of core damage progression. The Lipinski model, based on flows in the bed, has been used to predict the coolability, but uncertainties exist in the turbulent permeability. Models based on flooding at the top of the bed either have a dimensional viscosity term, or no viscosity dependence, thus limiting their applicability. This paper presents a dimensionless correlation based on flooding data thatmore » involves a liquid Reynolds number. The derived dryout model from this correlation is compared with data for deep beds of large particles at atmospheric pressure, and with other models over a wide pressure range. It is concluded that the present model can give quite accurate predictions for the dryout heat flux of particle beds formed during a light water reactor accident and it is easy to use and agrees with the Lipinski n = 5 model, which requires iterative calculations.« less

Consequences of the Ion Cyclotron Instability in the Inner Magnetospheric Plasma

NASA Technical Reports Server (NTRS)

Khazanov, George V.

2011-01-01

The inner magnetospheric plasma is a very unique composition of different plasma particles and waves. Among these plasma particles and waves are Ring Current (RC) particles and Electromagnetic Ion Cyclotron (EMIC) waves. The RC is the source of free energy for the EMIC wave excitation provided by a temperature anisotropy of RC ions, which develops naturally during inward E x B convection from the plasma sheet. The cold plasmasphere, which is under the strong influence of the magnetospheric electric field, strongly mediates the RC-EMIC waves-coupling process, and ultimately becomes part of the particle and energy interplay, generated by the ion cyclotron instability of the inner magnetosphere. On the other hand, there is a strong influence of the RC on the inner magnetospheric electric and magnetic field configurations and these configurations, in turn, are important to RC dynamics. Therefore, one of the biggest needs for inner magnetospheric plasma physics research is the continued progression toward a coupled, interconnected system, with the inclusion of nonlinear feedback mechanisms between the plasma populations, the electric and magnetic fields, and plasma waves.

Countermeasures for space radiation induced adverse biologic effects

NASA Astrophysics Data System (ADS)

Kennedy, A. R.; Wan, X. S.

2011-11-01

Radiation exposure in space is expected to increase the risk of cancer and other adverse biological effects in astronauts. The types of space radiation of particular concern for astronaut health are protons and heavy ions known as high atomic number and high energy (HZE) particles. Recent studies have indicated that carcinogenesis induced by protons and HZE particles may be modifiable. We have been evaluating the effects of proton and HZE particle radiation in cultured human cells and animals for nearly a decade. Our results indicate that exposure to proton and HZE particle radiation increases oxidative stress, cytotoxicity, cataract development and malignant transformation in in vivo and/or in vitro experimental systems. We have also shown that these adverse biological effects can be prevented, at least partially, by treatment with antioxidants and some dietary supplements that are readily available and have favorable safety profiles. Some of the antioxidants and dietary supplements are effective in preventing radiation induced malignant transformation in vitro even when applied several days after the radiation exposure. Our recent progress is reviewed and discussed in the context of the relevant literature.

Paramyxovirus glycoprotein incorporation, assembly and budding: a three way dance for infectious particle production.

PubMed

El Najjar, Farah; Schmitt, Anthony P; Dutch, Rebecca Ellis

2014-08-07

Paramyxoviruses are a family of negative sense RNA viruses whose members cause serious diseases in humans, such as measles virus, mumps virus and respiratory syncytial virus; and in animals, such as Newcastle disease virus and rinderpest virus. Paramyxovirus particles form by assembly of the viral matrix protein, the ribonucleoprotein complex and the surface glycoproteins at the plasma membrane of infected cells and subsequent viral budding. Two major glycoproteins expressed on the viral envelope, the attachment protein and the fusion protein, promote attachment of the virus to host cells and subsequent virus-cell membrane fusion. Incorporation of the surface glycoproteins into infectious progeny particles requires coordinated interplay between the three viral structural components, driven primarily by the matrix protein. In this review, we discuss recent progress in understanding the contributions of the matrix protein and glycoproteins in driving paramyxovirus assembly and budding while focusing on the viral protein interactions underlying this process and the intracellular trafficking pathways for targeting viral components to assembly sites. Differences in the mechanisms of particle production among the different family members will be highlighted throughout.

Paramyxovirus Glycoprotein Incorporation, Assembly and Budding: A Three Way Dance for Infectious Particle Production

PubMed Central

El Najjar, Farah; Schmitt, Anthony P.; Dutch, Rebecca Ellis

2014-01-01

Paramyxoviruses are a family of negative sense RNA viruses whose members cause serious diseases in humans, such as measles virus, mumps virus and respiratory syncytial virus; and in animals, such as Newcastle disease virus and rinderpest virus. Paramyxovirus particles form by assembly of the viral matrix protein, the ribonucleoprotein complex and the surface glycoproteins at the plasma membrane of infected cells and subsequent viral budding. Two major glycoproteins expressed on the viral envelope, the attachment protein and the fusion protein, promote attachment of the virus to host cells and subsequent virus-cell membrane fusion. Incorporation of the surface glycoproteins into infectious progeny particles requires coordinated interplay between the three viral structural components, driven primarily by the matrix protein. In this review, we discuss recent progress in understanding the contributions of the matrix protein and glycoproteins in driving paramyxovirus assembly and budding while focusing on the viral protein interactions underlying this process and the intracellular trafficking pathways for targeting viral components to assembly sites. Differences in the mechanisms of particle production among the different family members will be highlighted throughout. PMID:25105277

Multi-strategy coevolving aging particle optimization.

PubMed

Iacca, Giovanni; Caraffini, Fabio; Neri, Ferrante

2014-02-01

We propose Multi-Strategy Coevolving Aging Particles (MS-CAP), a novel population-based algorithm for black-box optimization. In a memetic fashion, MS-CAP combines two components with complementary algorithm logics. In the first stage, each particle is perturbed independently along each dimension with a progressively shrinking (decaying) radius, and attracted towards the current best solution with an increasing force. In the second phase, the particles are mutated and recombined according to a multi-strategy approach in the fashion of the ensemble of mutation strategies in Differential Evolution. The proposed algorithm is tested, at different dimensionalities, on two complete black-box optimization benchmarks proposed at the Congress on Evolutionary Computation 2010 and 2013. To demonstrate the applicability of the approach, we also test MS-CAP to train a Feedforward Neural Network modeling the kinematics of an 8-link robot manipulator. The numerical results show that MS-CAP, for the setting considered in this study, tends to outperform the state-of-the-art optimization algorithms on a large set of problems, thus resulting in a robust and versatile optimizer.

Cosmic ray transport in astrophysical plasmas

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

Schlickeiser, R.

2015-09-15

Since the development of satellite space technology about 50 years ago the solar heliosphere is explored almost routinely by several spacecrafts carrying detectors for measuring the properties of the interplanetary medium including energetic charged particles (cosmic rays), solar wind particle densities, and electromagnetic fields. In 2012, the Voyager 1 spacecraft has even left what could be described as the heliospheric modulation region, as indicated by the sudden disappearance of low energy heliospheric cosmic ray particles. With the available in-situ measurements of interplanetary turbulent electromagnetic fields and of the momentum spectra of different cosmic ray species in different interplanetary environments, themore » heliosphere is the best cosmic laboratory to test our understanding of the transport and acceleration of cosmic rays in space plasmas. I review both the historical development and the current state of various cosmic ray transport equations. Similarities and differences to transport theories for terrestrial fusion plasmas are highlighted. Any progress in cosmic ray transport requires a detailed understanding of the electromagnetic turbulence that is responsible for the scattering and acceleration of these particles.« less

Capture of nonmagnetic particles and living cells using a microelectromagnetic system

NASA Astrophysics Data System (ADS)

Aki, Atsushi; Ito, Osamu; Morimoto, Hisao; Nagaoka, Yutaka; Nakajima, Yoshikata; Mizuki, Toru; Hanajiri, Tatsuro; Usami, Ron; Maekawa, Toru

2008-11-01

We develop a microelectromagnetic system to trap nonmagnetic materials such as micropolystyrene particles and yeast cells in particular areas. We fabricate gold films, the width of the central narrow part is 22 μm, and flow an electric current through the films. We then apply an external uniform dc magnetic field to weaken the local magnetic field at the narrow part so that a nonuniform magnetic field is produced. We demonstrate that the particles, which are dispersed in magnetic fluid, are successfully trapped at the narrow part of the film. We evaluate the driving force acting on a microparticle in the nonuniform magnetic field and carry out a Stokesian dynamics simulation of the motion of the particles. We show that yeast cells are also trapped at the narrow part of the film. Finally, we fabricate multichannel microelectromagnets so that yeast cells are trapped at multiple points in the microelectromagnetic system. The present system may be applied to cell transfection on a cell microarray and, therefore, eventually contribute to progress in the identification and determination technologies of different drug targets and the functions of genes and proteins.

The influence of temperature on limestone sulfation and attrition under fluidized bed combustion conditions

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

Montagnaro, Fabio; Salatino, Piero; Dipartimento di Ingegneria Chimica - Universita degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Napoli

2010-04-15

The influence of temperature on attrition of two limestones during desulfurization in a fluidized bed reactor was investigated. Differences in the microstructure of the two limestones were reflected by a different thickness of the sulfate shell formed upon sulfation and by a different value of the ultimate calcium conversion degree. Particle attrition and fragmentation were fairly small under moderately bubbling fluidization conditions for both limestones. An increase of temperature from 850 C to 900 C led to an increase of the attrition rate, most likely because of a particle weakening effect caused by a faster CO{sub 2} evolution during calcination.more » This weakening effect, however, was not sufficiently strong to enhance particle fragmentation in the bed. The progress of sulfation, associated to the build-up of a hard sulfate shell around the particles, led in any case to a decrease of the extent of attrition. Sulfation at 900 C was less effective than at 850 C, and this was shown to be related to the porosimetric features of the different samples. (author)« less

Recent trends in drug delivery system using protein nanoparticles.

PubMed

Sripriyalakshmi, S; Jose, Pinkybel; Ravindran, Aswathy; Anjali, C H

2014-09-01

Engineered nanoparticles that can facilitate drug formulation and passively target tumours have been under extensive research in recent years. These successes have driven a new wave of significant innovation in the generation of advanced particles. The fate and transport of diagnostic nanoparticles would significantly depend on nonselective drug delivery, and hence the use of high drug dosage is implemented. In this perspective, nanocarrier-based drug targeting strategies can be used which improve the selective delivery of drugs to the site of action, i.e. drug targeting. Pharmaceutical industries majorly focus on reducing the toxicity and side effects of drugs but only recently it has been realised that carrier systems themselves may pose risks to the patient. Proteins are compatible with biological systems and they are biodegradable. They offer a multitude of moieties for modifications to tailor drug binding, imaging or targeting entities. Thus, protein nanoparticles provide outstanding contributions as a carrier for drug delivery systems. This review summarises recent progress in particle-based therapeutic delivery and discusses important concepts in particle design and biological barriers for developing the next generation of particles drug delivery systems.

Mechanical Fracturing of Core-Shell Undercooled Metal Particles for Heat-Free Soldering.

PubMed

Çınar, Simge; Tevis, Ian D; Chen, Jiahao; Thuo, Martin

2016-02-23

Phase-change materials, such as meta-stable undercooled (supercooled) liquids, have been widely recognized as a suitable route for complex fabrication and engineering. Despite comprehensive studies on the undercooling phenomenon, little progress has been made in the use of undercooled metals, primarily due to low yields and poor stability. This paper reports the use of an extension of droplet emulsion technique (SLICE) to produce undercooled core-shell particles of structure; metal/oxide shell-acetate ('/' = physisorbed, '-' = chemisorbed), from molten Field's metal (Bi-In-Sn) and Bi-Sn alloys. These particles exhibit stability against solidification at ambient conditions. Besides synthesis, we report the use of these undercooled metal, liquid core-shell, particles for heat free joining and manufacturing at ambient conditions. Our approach incorporates gentle etching and/or fracturing of outer oxide-acetate layers through mechanical stressing or shearing, thus initiating a cascade entailing fluid flow with concomitant deformation, combination/alloying, shaping, and solidification. This simple and low cost technique for soldering and fabrication enables formation of complex shapes and joining at the meso- and micro-scale at ambient conditions without heat or electricity.

Laser Transmission Measurements and Plume Particle Size Distributions for Propellant Burn Tests at ATK Elkton in May 2012

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

Willitsford, Adam H.; Brown, David M.; Brown, Andrea M.

2014-08-28

Multi-wavelength laser transmittance was measured during a series of open-air propellant burn tests at Alliant Techsystems, Inc., in Elkton, MD, in May 2012. A Mie scattering model was combined with an alumina optical properties model in a simple single-scatter approach to fitting plume transmittance. Wavelength-dependent plume transmission curves were fit to the measured multi-wave- length transmittance data to infer plume particle size distributions at several heights in the plume. Tri-modal lognormal distributions described transmittance data well at all heights. Overall distributions included a mode with nanometer-scale diameter, a second mode at a diameter of ~0.5 µm, and a third, largermore » particle mode. Larger parti- cles measured 2.5 µm in diameter at 34 cm (14 in.) above the burning propellant surface, but grew to 4 µm in diameter at a height of 57 cm (22 in.), indicative of particle agglomeration in progress as the plume rises. This report presents data, analysis, and results from the study.« less

Strangeness Production in Jets with ALICE at the LHC

NASA Astrophysics Data System (ADS)

Smith, Chrismond; Harton, Austin; Garcia, Edmundo; Alice Collaboration

2016-03-01

The study of strange particle production is an important tool for understanding the properties of the hot and dense QCD medium created in heavy-ion collisions at ultra-relativistic energies. The study of strange particles in these collisions provides information on parton fragmentation, a fundamental QCD process. While measurements at low and intermediate pT, are already in progress at the LHC, the study of high momentum observables is equally important for a complete understanding of the QCD matter, this can be achieved by studying jet interactions. We propose the measurement of the characteristics of the jets containing strange particles. Starting with proton-proton collisions, we have calculated the inclusive pTJet spectra and the spectra for jets containing strange particles (K-short or lambda), and we are extending this analysis to lead-lead collisions. In this talk the ALICE experiment will be described, the methodology used for the data analysis and the available results will be discussed. This material is based upon work supported by the National Science Foundation under Grants PHY-1305280 and PHY-1407051.

Gas-Grain Simulation Facility: Fundamental studies of particle formation and interactions. Volume 2: Abstracts, candidate experiments and feasibility study

NASA Technical Reports Server (NTRS)

Fogleman, Guy (Editor); Huntington, Judith L. (Editor); Schwartz, Deborah E. (Editor); Fonda, Mark L. (Editor)

1989-01-01

An overview of the Gas-Grain Simulation Facility (GGSF) project and its current status is provided. The proceedings of the Gas-Grain Simulation Facility Experiments Workshop are recorded. The goal of the workshop was to define experiments for the GGSF--a small particle microgravity research facility. The workshop addressed the opportunity for performing, in Earth orbit, a wide variety of experiments that involve single small particles (grains) or clouds of particles. Twenty experiments from the fields of exobiology, planetary science, astrophysics, atmospheric science, biology, physics, and chemistry were described at the workshop and are outlined in Volume 2. Each experiment description included specific scientific objectives, an outline of the experimental procedure, and the anticipated GGSF performance requirements. Since these experiments represent the types of studies that will ultimately be proposed for the facility, they will be used to define the general science requirements of the GGSF. Also included in the second volume is a physics feasibility study and abstracts of example Gas-Grain Simulation Facility experiments and related experiments in progress.

Cerebrospinal Fluid Particles in Alzheimer Disease and Parkinson Disease

PubMed Central

Yang, Yue; Keene, C. Dirk; Peskind, Elaine R.; Galasko, Douglas R.; Hu, Shu-Ching; Cudaback, Eiron; Wilson, Angela M.; Li, Ge; Yu, Chang-En; Montine, Kathleen S.; Zhang, Jing; Baird, Geoffrey S.; Hyman, Bradley T.; Montine, Thomas J.

2015-01-01

Human cerebrospinal fluid (CSF) contains diverse lipid particles, including lipoproteins that are distinct from their plasma counterparts and contain apolipoprotein (apo) E isoforms, apoJ, and apoAI, and extracellular vesicles, which can be detected by annexin V binding. The aim of this study was to develop a method to quantify CSF particles and evaluate their relationship to aging and neurodegenerative diseases. We used a flow cytometric assay to detect annexin V-, apoE-, apoAI-, apoJ- and amyloid (A) β42-positive particles in CSF from 131 research volunteers who were neurologically normal or had mild cognitive impairment (MCI), Alzheimer disease (AD) dementia, or Parkinson disease. APOE ε4/ε4 participants had CSF apoE-positive particles that were more frequently larger but at an 88% lower level vs. those in APOE ε3/ε3 or APOE ε3/ε4 patients; this finding was reproduced in conditioned medium from mouse primary glial cell cultures with targeted replacement of apoE. CSF apoE-positive and β-amyloid (Aβ42)-positive particle concentrations were persistently reduced one-third to one-half in middle and older age subjects; apoAI-positive particle concentration progressively increased approximately 2-fold with age. Both apoAI-positive and annexin V-positive CSF particle levels were reduced one-third to one-half in CSF of MCI and/or AD dementia patients vs. age-matched controls. Our approach provides new methods to investigate CNS lipid biology in relation to neurodegeneration and perhaps develop new biomarkers for diagnosis or treatment monitoring. PMID:26083568

Temperature profiles for laser-induced heating of nanocrystals embedded in glass matrices

NASA Astrophysics Data System (ADS)

Bhatnagar, Promod K.; Nagpal, Swati

2001-05-01

Quantum confined nanostructures are very important because of their application towards optoelectronic devices. Commercial colored glass filters, which have large semiconductor particles, are being used to manufacture nanocrystals by suitable heat treatments. The progress in this area has been hampered by high size dispersion of these dots in the glass matrix which leads to reduction in higher order susceptibility thereby reducing non-linearity. In the present paper attempt has been made to theoretically model the temperature profiles of a laser irradiated CdS doped Borosilicate sample. Laser being used has a beam diameter of 1.5 mm and energy for 10 nsec pulse is 10 mJ. Two different particle radii of 5 nm and 10 nm have been considered. It is found that larger particles reach higher temperatures for the same pulse characteristics. This is because smaller particles have larger surface to volume ratio and hence dissipates out heat faster to the surrounding. Hence bigger particles will reach dissolution temperature faster than smaller particle and particle beyond a certain size should dissolve in the glass matrix when a sample is heat treated by laser. This could lead to a reduction in size dispersion of the nanocrystals. Also photodarkening effect found in semiconductor doped glasses is a big handicap for practical application of these materials in fast optical switching and non-linear optical devices. Photodarkening effect has been established to be a photochemical effect and it is important to study the temperature profiles around a particle since it will effect the impurity migration.

A Physical Based Formula for Calculating the Critical Stress of Snow Movement

NASA Astrophysics Data System (ADS)

He, S.; Ohara, N.

2016-12-01

In snow redistribution modeling, one of the most important parameters is the critical stress of snow movement, which is difficult to estimate from field data because it is influenced by various factors. In this study, a new formula for calculating critical stress of snow movement was derived based on the ice particle sintering process modeling and the moment balance of a snow particle. Through this formula, the influences of snow particle size, air temperature, and deposited time on the critical stress were explicitly taken into consideration. It was found that some of the model parameters were sensitive to the critical stress estimation through the sensitivity analysis using Sobol's method. The two sensitive parameters of the sintering process modeling were determined by a calibration-validation procedure using the observed snow flux data via FlowCapt. Based on the snow flux and metrological data observed at the ISAW stations (http://www.iav.ch), it was shown that the results of this formula were able to describe very well the evolution of the minimum friction wind speed required for the snow motion. This new formula suggested that when the snow just reaches the surface, the smaller snowflake can move easier than the larger particles. However, smaller snow particles require more force to move as the sintering between the snowflakes progresses. This implied that compact snow with small snow particles may be harder to erode by wind although smaller particles may have a higher chance to be suspended once they take off.

Evaluation of particle radiotherapy for the re-irradiation of recurrent intracranial meningioma.

PubMed

El Shafie, Rami A; Czech, Maja; Kessel, Kerstin A; Habermehl, Daniel; Weber, Dorothea; Rieken, Stefan; Bougatf, Nina; Jäkel, Oliver; Debus, Jürgen; Combs, Stephanie E

2018-05-08

With the advance of modern irradiation techniques, the role of radiotherapy (RT) for intracranial meningioma has increased significantly throughout the past years. Despite that tumor's generally favorable outcome with local control rates of up to 90% after ten years, progression after RT does occur. In those cases, re-irradiation is often difficult due to the limited radiation tolerance of the surrounding tissue. The aim of this analysis is to determine the value of particle therapy with its better dose conformity and higher biological efficacy for re-irradiating recurrent intracranial meningioma. It was performed within the framework of the "clinical research group heavy ion therapy" and funded by the German Research Council (DFG, KFO 214). Forty-two patients treated with particle RT (protons (n = 8) or carbon ions (n = 34)) for recurrent intracranial meningioma were included in this analysis. Location of the primary lesion varied, including skull base (n = 31), convexity (n = 5) and falx (n = 6). 74% of the patients were categorized high-risk according to histology with a WHO grading of II (n = 25) or III (n = 6), in the remaining cases histology was either WHO grade I (n = 10) or unknown (n = 1). Median follow-up was 49,7 months. In all patients, re-irradiation could be performed safely without interruptions due to side effects. No grade IV or V toxicities according to CTCAE v4.0 were observed. Particle RT offered good overall local control rates with 71% progression-free survival (PFS) after 12 months, 56,5% after 24 months and a median PFS of 34,3 months (95% CI 11,7-56,9). Histology had a significant impact on PFS yielding a median PFS of 25,7 months (95% CI 5,8-45,5) for high-risk histology (WHO grades II and III) while median PFS was not reached for low-risk tumors (WHO grade I) (p = 0,03). Median time to local progression was 15,3 months (Q1-Q3 8,08-34,6). Overall survival (OS) after re-irradiation was 89,6% after 12 months and 71,4% after 24 months with a median OS of 61,0 months (95% CI 34,2-87,7). Again, WHO grading had an effect, as median OS for low-risk patients was not reached whereas for high-risk patients it was 45,5 months (95% CI 35,6-55,3). Re-irradiation using particle therapy is an effective method for the treatment of recurrent meningiomas. Interdisciplinary decision making is necessary to guarantee best treatment for every patient.

Aggregation of asbestos fibers in water: role of solution chemistry

NASA Astrophysics Data System (ADS)

Wu, L.; Ortiz, C. P.; Jerolmack, D. J.

2016-12-01

Aggregation kinetics and stability of colloidal particles have been extensively studied using bulk techniques such as dynamic light scattering; these techniques involve large ensembles of particles and interpretation of results is difficult when particles are non-spherical and poorly characterized, as is always the case with non-ideal natural hazardous materials such as asbestos fibers. These difficulties hinder greatly progress on fundamental understanding of whether the classic colloidal aggregation theories can be applied to natural materials and how the heterogeneity of particles (e.g., shape) affects the colloidal aggregation kinetics and structure. By using in-situ microscopy and particle tracking techniques, we were able to observe the particle-by-particle growth of aggregated formed by elongated particles (synthetic glass rods and natural asbestos fibers) and demonstrated the rod-shaped geometry induced novel structures and growth dynamics that challenge existing theory. In this study, we continue to use asbestos as model system of elongated colloidal contaminant, and investigate the effects of changing solution chemistry (e.g., ionic strength, pH, and natural organic matter (NOM)), on growth dynamics and aggregates structure. The results show that aggregate growth curves are self-similar with a characteristic timescale that increases with increasing pH. By varying ionic strength for fixed pH values, we determine that the ccc is sensitive to pH. Fractal dimension decreases slightly with increasing pH and decreasing ionic strength, indicating that stronger inter-particle repulsion create sparser aggregates; however, the magnitude of the solution chemistry effects is much smaller than that of colloid shape. In monovalent solutions, regardless of their concentration, HA drastically reduces the aggregation kinetics of asbestos fiber. This work may lead to enhanced prediction of the colloidal contaminants' mobility in the environment, bioavailability, and toxicity to organisms.

Special section containing papers presented at the 13th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (Beijing, China, 17-20 September 2013) Special section containing papers presented at the 13th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (Beijing, China, 17-20 September 2013)

NASA Astrophysics Data System (ADS)

Lin, Z.

2014-10-01

In magnetic fusion plasmas, a significant fraction of the kinetic pressure is contributed by superthermal charged particles produced by auxiliary heating (fast ions and electrons) and fusion reactions (a-particles). Since these energetic particles are often far away from thermal equilibrium due to their non-Maxwellian distribution and steep pressure gradients, the free energy can excite electromagnetic instabilities to intensity levels well above the thermal fluctuations. The resultant electromagnetic turbulence could induce large transport of energetic particles, which could reduce heating efficiency, degrade overall plasma confinement, and damage fusion devices. Therefore, understanding and predicting energetic particle confinement properties are critical to the success of burning plasma experiments such as ITER since the ignition relies on plasma self-heating by a-particles. To promote international exchanges and collaborations on energetic particle physics, the biannual conference series under the auspices of the International Atomic Energy Agency (IAEA) were help in Kyiv (1989), Aspenas (1991), Trieste (1993), Princeton (1995), JET/Abingdon (1997), Naka (1999), Gothenburg (2001), San Diego (2003), Takayama (2005), Kloster Seeon (2007), Kyiv (2009), and Austin (2011). The papers in this special section were presented at the most recent meeting, the 13th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems, which was hosted by the Fusion Simulation Center, Peking University, Beijing, China (17-20 September 2013). The program of the meeting consisted of 71 presentations, including 13 invited talks, 26 oral contributed talks, 30 posters, and 2 summary talks, which were selected by the International Advisory Committee (IAC). The IAC members include H. Berk, L.G. Eriksson, A. Fasoli, W. Heidbrink, Ya. Kolesnichenko, Ph. Lauber, Z. Lin, R. Nazikian, S. Pinches, S. Sharapov, K. Shinohara, K. Toi, G. Vlad, and X.T. Ding. The conference program, abstracts of all papers, and slides of oral presentations are available at the conference website:www.phy.pku.edu.cn/fsc/w18419.jsp As a measure of the breadth in current research activities, a wide range of topics in energetic particle physics were covered in the meeting program, including dynamics of various Alfvén eigenmodes and energetic particle modes, energetic particle transport, energetic particle effects on magnetohydrodynamic (MHD) modes, runaway electrons, and diagnostics of energetic particles and neutrons. Energetic particle experiments were reported on tokamaks, stellarators, spherical tori, reversed field pinches, and linear devices. Most of the papers have direct comparisons between experimental data and simulation results, a very healthy trend in the research of energetic particle physics. As an indication for the depth in current research activities and possible future directions in energetic particle physics, some exciting progress reported at the meeting is highlighted here. The 3D fields of resonant magnetic perturbations (RMP) for controlling edge localized modes (ELM) are found to drive significant ripple loss of fast ions in DIII-D and ASDEX-U experiments. Similar loss is predicted for ITER RMP fields in the vacuum approximation. Fortunately, plasma response to RMP fields is found by the simulation to reduce the loss of fast ions and α-particles to a benign level. These results call for more accurate measurements and more reliable modeling of the plasma response to RMP fields in existing tokamak experiments and in future ITER experiments. Interesting progress on energetic particle transport by Alfvén eigenmodes was made in reduced 1D models based on the critical gradients model, in which energetic particle pressure gradients are relaxed to the local threshold of Alfvén eigenmode stability. Some experimental support for the critical gradient model was reported in DIII-D off-axis neutral beam injection (NBI) experiments, in which the fast-ion density relaxes to similar profiles for all injection angles. Further verification and validation of these reduced models by existing tokamak experiments and nonlinear simulations are needed. Impressive progress in first-principles simulations of Alfvén eigenmodes and energetic particle transport was prominently featured at the meeting. Rigorous verification and validation have been successfully carried out for global gyrokinetic simulations of Alfvén eigenmodes with kinetic effects of thermal plasmas and non-perturbative contributions by energetic particles. The gyrokinetic turbulence simulation provides an indispensable new capability for studying the nonlinear physics of energetic particles and Alfvén eigenmodes by incorporating important physics of radial variations and toroidal mode coupling. For example, gyrokinetic simulations have found nonlinear oscillations of Alfvén eigenmode amplitude and frequency consistent with experimental observations. With better understanding of linear and nonlinear properties of Alfvén eigenmodes, a fruitful future direction is the self-consistent simulation of energetic particle transport, which requires long time simulations of nonlinear interactions between multiple Alfvén eigenmodes. A significant step in this direction has been taken by MHD-gyrokinetic hybrid simulations, which have demonstrated that fast ion profile is flattened by enhanced transport due to resonance overlaps in multiple interacting Alfvén eigenmodes with realistic amplitudes. A very interesting physics here is that the re-distribution of the energetic particle profile by an initially dominant Alfvén eigenmode leads to the excitation of other Alfvén eigenmodes. The broaden phase space volume for the extraction of free energy can then drive large fluctuation amplitudes and enhanced energetic particle transport. Some experimental evidences of such indirect interaction of multiple modes through energetic particles were observed in JT-60U and ASDEX-U experiments. Thirteen papers presented at the meeting were reviewed to the usual high standard of Nuclear Fusion and published in this special section. On behalf of the IAC, I would like to thank all participants for their contributions to this conference and to thank Nuclear Fusion for publishing this special section. The next meeting of this series will be organized by Simon Pinches and will be held at the IAEA headquarters in Vienna, in the fall of 2015.

Alginate Particles with Ovalbumin (OVA) Peptide Can Serve as a Carrier and Adjuvant for Immune Therapy in B16-OVA Cancer Model.

PubMed

Zhu, Longbao; Ge, Fei; Yang, Liangjun; Li, Wanzhen; Wei, Shenghua; Tao, Yugui; Du, Guocheng

2017-04-28

BACKGROUND Alginate is a natural polysaccharide obtained from brown algae and has been shown to have numerous applications in biomedical science, such as wound healing, delivery of bioactive agents, and cell transplantation. Ovalbumin (OVA) peptide 323-339 has been reported to be involved in immune response.  MATERIAL AND METHODS This work investigated the use of alginate particles as a carrier and adjuvant for the immune therapy of cancer. Alginate particles loaded with OVA peptide were produced via emulsion. A tumor model was established in C57BL/6J mice via subcutaneous injection of 3×105 B16-OVA tumor cells. The effect of alginate/OVA peptide on cell viability was analyzed by use of the CCK-8 assay kit. Activation of macrophages was examined by checking cell surface makers CD40 and CD86 by FACs. RESULTS Alginate/OVA peptide inhibited tumor progression more effectively than using the peptide alone. The viability and uptake study illustrated that this particle is safe and non-toxic. The activation study demonstrated that alginate particles can promote the activation of surface markers on macrophages. ELISA assay showed that the particles with peptide can promote the secretion of inflammatory and effector cytokines from macrophages.  CONCLUSIONS This study demonstrated that alginate has dual functions in immune therapy of cancer, serving both as a carrier and an adjuvant.

Hidden Variables and Placebo Effects

NASA Astrophysics Data System (ADS)

Goradia, Shantilal

2006-03-01

God's response to prayers and placebo leads to a question. How does He respond deterministically? He may be controlling at least one of the two variables of the uncertainty principle by extending His invisible soul to each body particle locally. Amazingly, many Vedic verses support this answer. One describes the size of the soul as arithmetically matching the size of the nucleons as if a particle is a soul. One gives a name meaning particle soul (anu-atma), consistent with particle's indeterministic behavior like that of (soulful) bird’s flying in any directions irrespective of the direction of throw. One describes souls as eternal consistent with the conservation of baryon number. One links the souls to the omnipresent (param- atma) like Einstein Rosen bridges link particles to normal spacetime. One claims eternal coexistence of matter and soul as is inflationary universe in physics/0210040 V2. The implicit scientific consistency of such verses makes the relationship of particle source of consciousness to the omnipresent Supreme analogous to the relationship of quantum source of gravitons in my gr-qc/0507130 to normal spacetime This frees us from the postulation of quantum wormholes and quantum foam. Dr. Hooft's view in ``Does God play dice,'' Physicsword, Dec 2005 seems consistent with my progressive conference presentations in Russia, Europe, India, and USA (Hindu University) in 2004/05. I see implications for nanoscience.

Partially Hydrolyzed Poly(n-propyl-2-oxazoline): Synthesis, Aqueous Solution Properties, and Preparation of Gene Delivery Systems.

PubMed

Mees, Maarten; Haladjova, Emi; Momekova, Denitsa; Momekov, Georgi; Shestakova, Pavletta S; Tsvetanov, Christo B; Hoogenboom, Richard; Rangelov, Stanislav

2016-11-14

Random copolymers of n-propyl-2-oxazoline and ethylenimine (PPrOx-PEI) were prepared by partial acidic hydrolysis of poly(n-propyl-2-oxazoline) (PPrOx). Dynamic and electrophoretic light scattering and diffusion-ordered NMR spectroscopy were utilized to investigate aqueous solution properties of the copolymers. Above a specific cloud point temperature, well-defined nanoparticles were formed. The latter consisted of a core composed predominantly of PPrOx and a thin positively charged shell from PEI moieties that mediated formation of polyplexes with DNA. The polyplexes were prepared at 65 °C at varying N/P (amine-to-phosphate groups) ratios. They underwent structural changes upon temperature variations 65-25-37 °C depending on N/P. At N/P < 2, the polyplex particles underwent minor changes because of formation of a surface layer of DNA that acted as a barrier and prevented swelling and disintegration of the initial particles. Dramatic rearrangements at N/P ≥ 2 resulting in large swollen microgel particles were overcome by coating of the polyplex particles with a cross-linked polymeric shell. The shell retained the colloidal stability and preserved the physicochemical parameters of the initial polyplex particles while it reduced the high surface potential values. Progressive loss of cytotoxicity upon complexation with DNA and coating of polyplex particles was displayed.

Final Progress Report: Internship at Los Alamos National Laboratory

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

Dunham, Ryan Q.

2012-08-10

Originally I was tasked fluidized bed modeling, however, I changed projects. While still working with ANSYS Fluent, I performed a study of particle tracks in glove boxes. This is useful from a Health-Physics perspective, dealing respirable particles that can be hazardous to the human body. I iteratively tested different amounts of turbulent particles in a steady-state flow. The goal of this testing was to discover how Fluent handles built-in Rosin-Rammler distributions for particle injections. I worked on the health physics flow problems and distribution analysis under the direction of two mentors, Bruce Letellier and Dave Decroix. I set up andmore » ran particle injection calculations using Fluent. I tried different combinations of input parameters to produce sets of 500,000, 1 million, and 1.5 million particles to determine what a good test case would be for future experiments. I performed a variety of tasks in my work as an Undergraduate Student Intern at LANL this summer, and learned how to use a powerful CFD application in addition to expanding my skills in MATLAB. I enjoyed my work at LANL and hope to be able to use the experience here to further my career in the future working in a security-conscious environment. My mentors provided guidance and help with all of my projects and I am grateful for the opportunity to work at Los Alamos National Laboratory.« less

Spectroscopy, Manipulation and Trapping of Neutral Atoms, Molecules, and Other Particles Using Optical Nanofibers: A Review

PubMed Central

Morrissey, Michael J.; Deasy, Kieran; Frawley, Mary; Kumar, Ravi; Prel, Eugen; Russell, Laura; Truong, Viet Giang; Chormaic, Síle Nic

2013-01-01

The use of tapered optical fibers, i.e., optical nanofibers, for spectroscopy and the detection of small numbers of particles, such as neutral atoms or molecules, has been gaining interest in recent years. In this review, we briefly introduce the optical nanofiber, its fabrication, and optical mode propagation within. We discuss recent progress on the integration of optical nanofibers into laser-cooled atom and vapor systems, paying particular attention to spectroscopy, cold atom cloud characterization, and optical trapping schemes. Next, a natural extension of this work to molecules is introduced. Finally, we consider several alternatives to optical nanofibers that display some advantages for specific applications. PMID:23945738

The linac coherent light source single particle imaging road map

PubMed Central

Aquila, A.; Barty, A.; Bostedt, C.; Boutet, S.; Carini, G.; dePonte, D.; Drell, P.; Doniach, S.; Downing, K. H.; Earnest, T.; Elmlund, H.; Elser, V.; Gühr, M.; Hajdu, J.; Hastings, J.; Hau-Riege, S. P.; Huang, Z.; Lattman, E. E.; Maia, F. R. N. C.; Marchesini, S.; Ourmazd, A.; Pellegrini, C.; Santra, R.; Schlichting, I.; Schroer, C.; Spence, J. C. H.; Vartanyants, I. A.; Wakatsuki, S.; Weis, W. I.; Williams, G. J.

2015-01-01

Intense femtosecond x-ray pulses from free-electron laser sources allow the imaging of individual particles in a single shot. Early experiments at the Linac Coherent Light Source (LCLS) have led to rapid progress in the field and, so far, coherent diffractive images have been recorded from biological specimens, aerosols, and quantum systems with a few-tens-of-nanometers resolution. In March 2014, LCLS held a workshop to discuss the scientific and technical challenges for reaching the ultimate goal of atomic resolution with single-shot coherent diffractive imaging. This paper summarizes the workshop findings and presents the roadmap toward reaching atomic resolution, 3D imaging at free-electron laser sources. PMID:26798801

The linac coherent light source single particle imaging road map

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

Aquila, A.; Barty, A.; Bostedt, C.

Intense femtosecond x-ray pulses from free-electron laser sources allow the imaging of individual particles in a single shot. Early experiments at the Linac Coherent Light Source (LCLS) have led to rapid progress in the field and, so far, coherent diffractive images have been recorded from biological specimens, aerosols, and quantum systems with a few-tens-of-nanometers resolution. In March 2014, LCLS held a workshop to discuss the scientific and technical challenges for reaching the ultimate goal of atomic resolution with single-shot coherent diffractive imaging. This paper summarizes the workshop findings and presents the roadmap toward reaching atomic resolution, 3D imaging at free-electronmore » laser sources.« less

Geochemical and radiological characterization of soils from former radium processing sites

USGS Publications Warehouse

Landa, E.R.

1984-01-01

Soil samples were collected from former radium processing sites in Denver, CO, and East Orange, NJ. Particle-size separations and radiochemical analyses of selected samples showed that while the greatest contents of both 226Ra and U were generally found in the finest (< 45 ??m) fraction, the pattern was not always of progressive increase in radionuclide content with decreasing particle size. Leaching tests on these samples showed a large portion of the 225Ra and U to be soluble in dilute hydrochloric acid. Radon-emanation coefficients measured for bulk samples of contaminated soil were about 20%. Recovery of residual uranium and vanadium, as an adjunct to any remedial action program, appears unlikely due to economic considerations.

Simulation studies for the PANDA experiment

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

Kopf, B.

2005-10-26

One main component of the planned Facility for Antiproton and Ion Research (FAIR) is the High Energy Storage Ring (HESR) at GSI, Darmstadt, which will provide cooled antiprotons with momenta between 1.5 and 15 GeV/c. The PANDA experiment will investigate p-barannihilations with internal hydrogen and nuclear targets. Due to the planned extensive physics program a multipurpose detector with nearly complete solid angle coverage, proper particle identification over a large momentum range, and high resolution calorimetry for neutral particles is required. For the optimization of the detector design simulation studies of several benchmark channels are in progress which are covering themore » most relevant physics topics. Some important simulation results are discussed here.« less

Conference scene: molecular pharming: manufacturing medicines in plants.

PubMed

Lössl, Andreas G; Clarke, Jihong L

2013-01-01

Within the expanding area of molecular pharming, the development of plants for manufacturing immunoglobulins, enzymes, virus-like particles and vaccines has become a major focus point. On 21 September 2012, the meeting 'Molecular Pharming - recent progress in manufacturing medicines in plants', hosted by EuroSciCon, was held at the Bioscience Catalyst campus, Stevenage, UK. The scientific program of this eventful meeting covered diverse highlights of biopharming: monoclonal antibodies, virus-like particles from transient and chloroplast expression systems, for example, for Dengue and HPV, apolipoproteins from safflower seeds, and new production platforms, such as potato or hydroponics by rhizosecretion. This report summarizes the stimulating scientific presentations and fruitful panel discussions on the current topics in this promising research field.

Progress in Developing Virus-like Particle Influenza Vaccines

PubMed Central

Quan, Fu-Shi; Lee, Young-Tae; Kim, Ki-Hye; Kim, Min-Chul; Kang, Sang-Moo

2016-01-01

Summary Recombinant vaccines based on virus-like particles (VLPs) or nanoparticles have been successful in their safety and efficacy in preclinical and clinical studies. The technology of expressing enveloped VLP vaccines has combined with molecular engineering of proteins in membrane-anchor and immunogenic forms mimicking the native conformation of surface proteins on the enveloped viruses. This review summarizes recent developments in influenza VLP vaccines against seasonal, pandemic, and avian influenza viruses from the perspective of use in humans. The immunogenicity and efficacies of influenza VLP vaccine in the homologous and cross-protection were reviewed. Discussions include limitations of current influenza vaccination strategies and future directions to confer broadly cross protective new influenza vaccines as well as vaccination. PMID:27058302

Laboratory-directed research and development: FY 1996 progress report

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

Vigil, J.; Prono, J.

1997-05-01

This report summarizes the FY 1996 goals and accomplishments of Laboratory-Directed Research and Development (LDRD) projects. It gives an overview of the LDRD program, summarizes work done on individual research projects, and provides an index to the projects` principal investigators. Projects are grouped by their LDRD component: Individual Projects, Competency Development, and Program Development. Within each component, they are further divided into nine technical disciplines: (1) materials science, (2) engineering and base technologies, (3) plasmas, fluids, and particle beams, (4) chemistry, (5) mathematics and computational sciences, (6) atomic and molecular physics, (7) geoscience, space science, and astrophysics, (8) nuclear andmore » particle physics, and (9) biosciences.« less

On the peculiarities of LDA method in two-phase flows with high concentrations of particles

NASA Astrophysics Data System (ADS)

Poplavski, S. V.; Boiko, V. M.; Nesterov, A. U.

2016-10-01

Popular applications of laser Doppler anemometry (LDA) in gas dynamics are reviewed. It is shown that the most popular method cannot be used in supersonic flows and two-phase flows with high concentrations of particles. A new approach to implementation of the known LDA method based on direct spectral analysis, which offers better prospects for such problems, is presented. It is demonstrated that the method is suitable for gas-liquid jets. Owing to the progress in laser engineering, digital recording of spectra, and computer processing of data, the method is implemented at a higher technical level and provides new prospects of diagnostics of high-velocity dense two-phase flows.

Experimental Rock-on-Rock Abrasive Wear Under Aqueous Conditions: its Role in Subglacial Abrasion

NASA Astrophysics Data System (ADS)

Rutter, E. H.; Lee, A. G.

2003-12-01

We have determined experimentally the rate of abrasive wear of rock on rock for a range of rock types as a function of normal stress and shear displacement. Unlike abrasive wear in fault zones, where wear products accumulate as a thickening gouge zone, in our experiments wear particles were removed by flowing water. The experiments are thus directly pertinent to one of the most important processes in subglacial erosion, and to some extent in river incision. Wear was produced between rotating discs machined from rock samples and measured from the progressive approach of the disc axes towards each other under various levels of normal load. Shear displacements of several km were produced. Optical and scanning electron microscopy were used to study the worn rock surfaces, and particle size distributions in wear products were characterized using a laser particle size analyzer. Rock types studied were sandstones of various porosities and cement characteristics, schists and a granite. In all cases abrasion rate decreased logarithmically with displacement by up to 2 orders of magnitude until a steady state was approached, but only after at least 1 km displacement. The more porous, less-well cemented rocks wore fastest. Amount of abrasion could be characterized quantitatively using an exponentially decaying plus a steady-state term. Wear rate increased non-linearly with normal contact stress, apparently to an asymptote defined by the unconfined compressive strength. Microstructural study showed that the well-cemented and/or lowest porosity rocks wore by progressive abrasion of grains without plucking, whereas whole grains were plucked out of weakly-cemented and/or more porous rocks. This difference in behavior was reflected in wear-product particle size distributions. Where whole-grain plucking was possible, wear products were dominated by particles of the original grain size rather than finer rock flour. Comparison of our results to glacier basal abrasive wear estimated from suspended sediment load (Findeln Glacier, Switzerland) showed the steady-state experimental data seriously to underestimate the natural wear rate. This suggests continuous resetting of the subglacial surface occurs, so that wear is continuously in the 'running-in' stage.

Proton and carbon ion radiotherapy for primary brain tumors delivered with active raster scanning at the Heidelberg Ion Therapy Center (HIT): early treatment results and study concepts

PubMed Central

2012-01-01

Background Particle irradiation was established at the University of Heidelberg 2 years ago. To date, more than 400 patients have been treated including patients with primary brain tumors. In malignant glioma (WHO IV) patients, two clinical trials have been set up-one investigating the benefit of a carbon ion (18 GyE) vs. a proton boost (10 GyE) in addition to photon radiotherapy (50 Gy), the other one investigating reirradiation with escalating total dose schedules starting at 30 GyE. In atypical meningioma patients (WHO °II), a carbon ion boost of 18 GyE is applied to macroscopic tumor residues following previous photon irradiation with 50 Gy. This study was set up in order to investigate toxicity and response after proton and carbon ion therapy for gliomas and meningiomas. Methods 33 patients with gliomas (n = 26) and meningiomas (n = 7) were treated with carbon ion (n = 26) and proton (n = 7) radiotherapy. In 22 patients, particle irradiation was combined with photon therapy. Temozolomide-based chemotherapy was combined with particle therapy in 17 patients with gliomas. Particle therapy as reirradiation was conducted in 7 patients. Target volume definition was based upon CT, MRI and PET imaging. Response was assessed by MRI examinations, and progression was diagnosed according to the Macdonald criteria. Toxicity was classified according to CTCAE v4.0. Results Treatment was completed and tolerated well in all patients. Toxicity was moderate and included fatigue (24.2%), intermittent cranial nerve symptoms (6%) and single episodes of seizures (6%). At first and second follow-up examinations, mean maximum tumor diameters had slightly decreased from 29.7 mm to 27.1 mm and 24.9 mm respectively. Nine glioma patients suffered from tumor relapse, among these 5 with infield relapses, causing death in 8 patients. There was no progression in any meningioma patient. Conclusions Particle radiotherapy is safe and feasible in patients with primary brain tumors. It is associated with little toxicity. A positive response of both gliomas and meningiomas, which is suggested in these preliminary data, must be evaluated in further clinical trials. PMID:22436135

On the use of thermal NF3 as the fluorination and oxidation agent in treatment of used nuclear fuels

NASA Astrophysics Data System (ADS)

Scheele, Randall; McNamara, Bruce; Casella, Andrew M.; Kozelisky, Anne

2012-05-01

This paper presents results of our investigation on the use of nitrogen trifluoride as a fluorination or fluorination/oxidation agent for separating valuable constituents from used nuclear fuels by exploiting the different volatilities of the constituent fission product and actinide fluorides. Our thermodynamic calculations show that nitrogen trifluoride has the potential to produce volatile fission product and actinide fluorides from oxides and metals that can form volatile fluorides. Simultaneous thermogravimetric and differential thermal analyses show that the oxides of lanthanum, cerium, rhodium, and plutonium are fluorinated but do not form volatile fluorides when treated with nitrogen trifluoride at temperatures up to 550 °C. However, depending on temperature, volatile fluorides or oxyfluorides can form from nitrogen trifluoride treatment of the oxides of niobium, molybdenum, ruthenium, tellurium, uranium, and neptunium. Thermoanalytical studies demonstrate near-quantitative separation of uranium from plutonium in a mixed 80% uranium and 20% plutonium oxide. Our studies of neat oxides and metals suggest that the reactivity of nitrogen trifluoride may be adjusted by temperature to selectively separate the major volatile fuel constituent uranium from minor volatile constituents, such as Mo, Tc, Ru and from the non-volatile fuel constituents based on differences in their reaction temperatures and kinetic behaviors. This reactivity is novel with respect to that reported for other fluorinating reagents F2, BrF5, ClF3.

Optical properties of Sm3+ -doped TeO2sbnd WO3sbnd GeO2 glasses for solid state lasers

NASA Astrophysics Data System (ADS)

Subrahmanyam, T.; Gopal, K. Rama; Suvarna, R. Padma; Jamalaiah, B. Chinna; Rao, Ch Srinivasa

2018-03-01

Sm3+ -doped oxyfluoride tellurite-tungsten (TWGSm) glasses were prepared by conventional melt quenching method. The optical properties were investigated through photoluminescence excitation, emission and luminescence decay analysis. The optical band gap energy was determined as ∼3.425 eV for 1.0 mol% of Sm3+ -doped TWGSm glass. Upon 404 nm excitation, the TWGSm glasses emit luminescence through 4G5/2 → 6H5/2 (563 nm), 4G5/2 → 6H7/2 (600 nm), 4G5/2 → 6H9/2 (645 nm) and 4G5/2 → 6H11/2 (705 nm) transitions. The Judd-Ofelt analysis was performed using absorption spectrum and obtained radiative parameters were used to estimate the laser characteristics of present glasses. The concentration of Sm3+ has been optimized as 1.0 mol% for efficient luminescence. The luminescence decay of 4G5/2 emission level was studied by monitoring the emission and excitation wavelengths at 600 and 404 nm, respectively. The experimental lifetime of 4G5/2 level was decrease with increase of Sm3+ concentration. The 1.0 mol% of Sm3+ -doped TWGSm glass could be the best choice for solid state visible lasers to emit orange luminescence.

Energy transfer dynamics of Er3+/Nd3+ embedded SiO2-Al2O3-Na2CO3-SrF2-CaF2 glasses for optical communications

NASA Astrophysics Data System (ADS)

Gelija, Devarajulu; Kadathala, Linganna; Borelli, Deva Prasad Raju

2018-04-01

The fluorescence and upconversion studies of Er3+ doped and Er3+/Nd3+ co-doped silicate based oxyfluoride glasses have been systematically analyzed. The broad band NIR emissions (830-1700 nm), includes optical bands like O, E, S, C and L were observed in the Er3+-Nd3+ co-doped glasses. The NIR emission intensity peaks centered at 876, 1057, 1329 and 1534 nm were observed for the Er3+-Nd3+ co-doped glasses. In the co-doped samples the strongest emission intensity at 1534 nm increased up to 0.5 mol % and then decreased to 3.0 mol % of Nd3+ ions under the excitation of 980 nm. The upconversion studies of the co-doped samples were recorded under the excitation of 980 and 808 nm and found the upconversion emission peaks centered at 524, 530, 547, 590 and 656 nm. The energy transfer processes between the relevant excitation levels of Er3+ and Nd3+ ions and energy transfer efficiency were discussed. The obtained results indicate that Nd3+ can be an efficient sensitizer for Er3+ to enhance upconversion emission at green laser transition for sensors and NIR emission at 1534 nm for optical communication applications.

Luminescent properties of Eu{sup 2+}-doped BaGdF{sub 5} glass ceramics a potential blue phosphor for ultra-violet light-emitting diode

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

Zhang, Weihuan; Zhang, Yuepin, E-mail: zhangyuepin@nbu.edu.cn; Ouyang, Shaoye

2015-01-14

Eu{sup 2+} doped transparent oxyfluoride glass ceramics containing BaGdF{sub 5} nanocrystals were successfully fabricated by melt-quenching technique under a reductive atmosphere. The structure of the glass and glass ceramics were investigated by differential scanning calorimetry, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The luminescent properties were investigated by transmission, excitation, and emission spectra. The decay time of the Gd{sup 3+} ions at 312 nm excited with 275 nm were also investigated. The results of XRD and TEM indicated the existence of BaGdF5 nanocrystals in the transparent glass ceramics. The excitation spectra of Eu{sup 2+} doped glass ceramics showed an excellent overlapmore » with the main emission region of an ultraviolet light-emitting diode (UV-LED). Compared with the as-made glass, the emission of glass ceramics is much stronger by a factor of increasing energy transfer efficiency from Gd{sup 3+} to Eu{sup 2+} ions, the energy transfer efficiency from Gd{sup 3+} to Eu{sup 2+} ions was discussed. In addition, the chromaticity coordinates of glass and glass ceramics specimens were also discussed, which indicated that the Eu{sup 2+} doped BaGdF{sub 5} glass ceramics may be used as a potential blue-emitting phosphor for UV-LED.« less

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

Targove, J.D.

The columnar microstructure of most thermally evaporated thin films detrimentally affects many of their properties through a reduction in packing density. In this work, the author investigated ion-assisted deposition as a means of disrupting this columnar growth for a number of coating materials. A Kaufman hot-cathode ion source bombarded thermally evaporated films with low-energy (<1000 eV) positive ions during deposition in a cryopumped box coater. The author investigated MgF/sub 2/, Na/sub 3/AlF/sub 6/, AlF/sub 3/, LaF/sub 3/,CeF/sub 3/,NdF/sub 3/,Al/sub 2/O/sub 3/, and AlN. Argon ion bombardment of the fluoride coatings increased their packing densities dramatically. He achieved packing densities nearmore » unity without significant absorption for MgF/sub 2/,LaF/sub 3/, and NdF/sub 3/, while Na/sub 3/AlF/sub 6/,AlF/sub 3/, and CeF/sub 3/ began to absorb before unity packing density could be achieved. Fluorine was preferentially sputtered by the ion bombardment, creating anion vacancies. The films adsorbed water vapor and hydroxyl radicals from the residual chamber atmosphere. These filled the vacancy sites, eliminating absorption in the visible, but the oxygen complexes caused increased absorption in the ultraviolet. For LaF/sub 3/ and NdF/sub 3/, a sufficient amount of oxygen caused a phase transformation from the fluoride phase to an oxyfluoride phase.« less

Status of LDEF ionizing radiation measurements and analysis

NASA Technical Reports Server (NTRS)

Parnell, T. A.

1992-01-01

The LDEF-1 results from the particle astrophysics, radiation environments, and dosimetry measurements on LDEF-1 are summarized, including highlights from presentations at the 2nd symposium. Progress in using LDEF data to improve radiation environment models and calculation methods is reviewed. Radiation effects, or the lack thereof are discussed. Future plans of the LDEF Ionizing Radiation Special Investigation Group are presented.

The SPRING Nanoenergetics Hub at UTD

DTIC Science & Technology

2008-12-01

synthesis and processing of advanced nanostructured materials, the structure and property characterization needed for materials optimization, the...nano-particles into hexane solvent a deposited films. Here we are modeling that processes to see how the droplet evaporation progresses in time. What...nanofibers was determined by powder X-ray diffraction (XRD) (Scintag XDS 2000 X-ray diffractometer with Cu Ka radiation). The fiber morphology was

A Primer on Vibrational Ball Bearing Feature Generation for Prognostics and Diagnostics Algorithms

DTIC Science & Technology

2015-03-01

Atlas -Marks (Cone-Shaped Kernel) ........................................................36 8.7.7 Hilbert-Huang Transform...bearing surface and eventually progress to the surface where the material will separate. Also known as pitting, spalling, or flaking. • Wear ...normal degradation caused by dirt and foreign particles causing abrasion of the contact surfaces over time resulting in alterations in the raceway and

Some recent progress in classical general relativity

NASA Astrophysics Data System (ADS)

Finster, Felix; Smoller, Joel; Yau, Shing-Tung

2000-06-01

In this short survey paper, we shall discuss certain recent results in classical gravity. Our main attention will be restricted to two topics in which we have been involved; the positive mass conjecture and its extensions to the case with horizons, including the Penrose conjecture (Part I), and the interaction of gravity with other force fields and quantum-mechanical particles (Part II).

Reactor operations informal monthly report, May 1, 1995--May 31, 1995

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

Hauptman, H.M.; Petro, J.N.; Jacobi, O.

1995-05-01

This document is an informal progress report for the operational performance of the Brookhaven Medical Research Reactor, and the Brookhaven High Flux Beam Reactor, for the month of May, 1995. Both machines ran well during this period, with no reportable instrumentation problems, all scheduled maintenance performed, and only one reportable occurance, involving a particle on Vest Button, Personnel Radioactive Contamination.

Interaction between age of irradiation and age of testing in the disruption of operant performance using a ground-based model for exposure to cosmic rays

USDA-ARS?s Scientific Manuscript database

Exposure to HZE particles produces deficits in cognitive performance. While previous research has shown a progressive deterioration in cognitive performance in radiated rats as a function of age, the present experiment was designed to evaluate the effects of age of irradiation independently of the ...

Physics Division annual review, 1 April 1980-31 March 1981

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

Not Available

1982-06-01

Progress in nuclear physics research is reported in the following areas: medium-energy physics (pion reaction mechanisms, high-resolution studies and nuclear structure, and two-nucleon physics with pions and electrons); heavy-ion research at the tandem and superconducting linear accelerator (resonant structure in heavy-ion reactions, fusion cross sections, high angular momentum states in nuclei, and reaction mechanisms and distributions of reaction strengths); charged-particle research; neutron and photonuclear physics; theoretical physics (heavy-ion direct-reaction theory, nuclear shell theory and nuclear structure, nuclear matter and nuclear forces, intermediate-energy physics, microscopic calculations of high-energy collisions of heavy ions, and light ion direct reactions); the superconducting linac; acceleratormore » operations; and GeV electron linac. Progress in atomic and molecular physics research is reported in the following areas: dissociation and other interactions of energetic molecular ions in solid and gaseous targets, beam-foil research and collision dynamics of heavy ions, photoionization- photoelectron research, high-resolution laser rf spectroscopy with atomic and molecular beams, moessbauer effect research, and theoretical atomic physics. Studies on interactions of energetic particles with solids are also described. Publications are listed. (WHK)« less

Fabrication and Characterization of Quinoa Protein Nanoparticle-Stabilized Food-Grade Pickering Emulsions with Ultrasound Treatment: Interfacial Adsorption/Arrangement Properties.

PubMed

Qin, Xin-Sheng; Luo, Zhi-Gang; Peng, Xi-Chun

2018-05-02

The natural quinoa protein isolate (QPI) was largely reflected in the nanoparticle form at pH 7.0 (∼401 nm), and the ultrasound at 20 min progressively improved the contact angle (wettability) and surface hydrophobicity of the nanoparticles. Ultrasound process also modified the type of intraparticle interaction, and the internal forces of sonicated particles were largely maintained by both disulfide bonds and hydrophobic interaction forces. In emulsion system, the ultrasound progressively increased the emulsification efficiency of the QPI nanoparticles, particularly at high protein concentration ( c > 1%, w/ v) and higher emulsion stability against coalescence. As compared with the natural QPI-stabilized emulsions, the 20 min sonicated emulsions exhibited higher packing and adsorption at the protein interface. The microstructure of emulsions that occurs is bridging flocculation of droplets at low c (≤1%, w/ v), while the amount of protein particles could be high enough to cover the droplet surface at high c ( >1%, w/ v) with hexagonal array model arrangement. Thus these results illustrated that both natural and sonicated QPI nanoparticles could be performed as effective food-grade stabilizer for Pickering emulsion; however, the sonicated QPI nanoparticles exhibited much better emulsifying and interfacial properties.

Cross-separatrix Coupling in Nonlinear Global Electrostatic Turbulent Transport in C-2U

NASA Astrophysics Data System (ADS)

Lau, Calvin; Fulton, Daniel; Bao, Jian; Lin, Zhihong; Binderbauer, Michl; Tajima, Toshiki; Schmitz, Lothar; TAE Team

2017-10-01

In recent years, the progress of the C-2/C-2U advanced beam-driven field-reversed configuration (FRC) experiments at Tri Alpha Energy, Inc. has pushed FRCs to transport limited regimes. Understanding particle and energy transport is a vital step towards an FRC reactor, and two particle-in-cell microturbulence codes, the Gyrokinetic Toroidal Code (GTC) and A New Code (ANC), are being developed and applied toward this goal. Previous local electrostatic GTC simulations find the core to be robustly stable with drift-wave instability only in the scrape-off layer (SOL) region. However, experimental measurements showed fluctuations in both regions; one possibility is that fluctuations in the core originate from the SOL, suggesting the need for non-local simulations with cross-separatrix coupling. Current global ANC simulations with gyrokinetic ions and adiabatic electrons find that non-local effects (1) modify linear growth-rates and frequencies of instabilities and (2) allow instability to move from the unstable SOL to the linearly stable core. Nonlinear spreading is also seen prior to mode saturation. We also report on the progress of the first turbulence simulations in the SOL. This work is supported by the Norman Rostoker Fellowship.

Strange Particles and Heavy Ion Physics

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

Bassalleck, Bernd; Fields, Douglas

This very long-running grant has supported many experiments in nuclear and particle physics by a group from the University of New Mexico. The gamut of these experiments runs from many aspects of Strangeness Nuclear Physics, to rare Kaon decays, to searches for exotic Hadrons such as Pentaquark or H-Dibaryon, and finally to Spin Physics within the PHENIX collaboration at RHIC. These experiments were performed at a number of laboratories worldwide: first and foremost at Brookhaven National Lab (BNL), but also at CERN, KEK, and most recently at J-PARC. In this Final Technical Report we summarize progress and achievements for thismore » award since our last Progress Report, i.e. for the period of fall 2013 until the award’s termination on November 30, 2015. The report consists of two parts, representing our two most recent experimental efforts, participation in the Nucleon Spin Physics program of the PHENIX experiment at RHIC, the Relativistic Heavy Ion Collider at BNL – Task 1, led by Douglas Fields; and participation in several Strangeness Nuclear Physics experiments at J-PARC, the Japan Proton Accelerator Research Center in Tokai-mura, Japan – Task 2, led by Bernd Bassalleck.« less

From the sea to the laboratory: Characterization of microplastic as prerequisite for the assessment of ecotoxicological impact.

PubMed

Potthoff, Annegret; Oelschlägel, Kathrin; Schmitt-Jansen, Mechthild; Rummel, Christoph Daniel; Kühnel, Dana

2017-05-01

The presence of microplastic (MP) in the aquatic environment is recognized as a global-scale pollution issue. Secondary MP particles result from an ongoing fragmentation process governed by various biotic and abiotic factors. For a reliable risk assessment of these MP particles, knowledge about interactions with biota is needed. However, extensive testing with standard organisms under reproducible laboratory conditions with well-characterized MP suspensions is not available yet. As MP in the environment represents a mixture of particles differing in properties (e.g., size, color, polymer type, surface characteristics), it is likely that only specific particle fractions pose a threat towards organisms. In order to assign hazardous effects to specific particle properties, these characteristics need to be analyzed. As shown by the testing of particles (e.g. nanoparticles), characteristics other than chemical properties are important for the emergence of toxicity in organisms, and parameters such as surface area or size distribution need consideration. Therefore, the use of "well-defined" particles for ecotoxicological testing (i.e., standard particles) facilitates the establishment of causal links between physical-chemical properties of MP particles and toxic effects in organisms. However, the benefits of well-defined particles under laboratory conditions are offset by the disadvantage of the unknown comparability with MP in the environment. Therefore, weathering effects caused by biological, chemical, physical or mechanical processes have to be considered. To date, the characterization of the progression of MP weathering based on powder and suspension characterization methods is in its infancy. The aim of this commentary is to illustrate the prerequisites for testing MP in the laboratory from 3 perspectives: (i) knowledge of particle properties; (ii) behavior of MP in test setups involving ecotoxicological test organisms; and (iii) accordingly, test conditions that may need adjustment. Only under those prerequisites will reliable hazard assessment of MP be feasible. Integr Environ Assess Manag 2017;13:500-504. © 2017 SETAC. © 2017 SETAC.

Hysteretic dynamics of active particles in a periodic orienting field

PubMed Central

Romensky, Maksym; Scholz, Dimitri; Lobaskin, Vladimir

2015-01-01

Active motion of living organisms and artificial self-propelling particles has been an area of intense research at the interface of biology, chemistry and physics. Significant progress in understanding these phenomena has been related to the observation that dynamic self-organization in active systems has much in common with ordering in equilibrium condensed matter such as spontaneous magnetization in ferromagnets. The velocities of active particles may behave similar to magnetic dipoles and develop global alignment, although interactions between the individuals might be completely different. In this work, we show that the dynamics of active particles in external fields can also be described in a way that resembles equilibrium condensed matter. It follows simple general laws, which are independent of the microscopic details of the system. The dynamics is revealed through hysteresis of the mean velocity of active particles subjected to a periodic orienting field. The hysteresis is measured in computer simulations and experiments on unicellular organisms. We find that the ability of the particles to follow the field scales with the ratio of the field variation period to the particles' orientational relaxation time, which, in turn, is related to the particle self-propulsion power and the energy dissipation rate. The collective behaviour of the particles due to aligning interactions manifests itself at low frequencies via increased persistence of the swarm motion when compared with motion of an individual. By contrast, at high field frequencies, the active group fails to develop the alignment and tends to behave like a set of independent individuals even in the presence of interactions. We also report on asymptotic laws for the hysteretic dynamics of active particles, which resemble those in magnetic systems. The generality of the assumptions in the underlying model suggests that the observed laws might apply to a variety of dynamic phenomena from the motion of synthetic active particles to crowd or opinion dynamics. PMID:26040594

Colloidal Stability in Asymmetric Electrolytes: Modifications of the Schulze-Hardy Rule.

PubMed

Trefalt, Gregor; Szilagyi, Istvan; Téllez, Gabriel; Borkovec, Michal

2017-02-21

The Schulze-Hardy rule suggests a strong dependence of the critical coagulation concentration (CCC) on the ionic valence. This rule is addressed theoretically and confronted with recent experimental results. The commonly presented derivation of this rule assumes symmetric electrolytes and highly charged particles. Both assumptions are incorrect. Symmetric electrolytes containing multivalent ions are hardly soluble, and experiments are normally carried out with the well-soluble salts of asymmetric electrolytes containing monovalent and multivalent ions. In this situation, however, the behavior is completely different whether the multivalent ions represent the counterions or co-ions. When these ions represent the counterions, meaning that the multivalent ions have the opposite sign than the charge of the particle, they adsorb strongly to the particles. Thereby, they progressively reduce the magnitude of the surface charge with increasing valence. In fact, this dependence of the charge density on the counterion valence is mainly responsible for the decrease of the CCC with the valence. In the co-ion case, where the multivalent ions have the same sign as the charge of the particle, the multivalent ions are repelled from the particles, and the surfaces remain highly charged. In this case, the inverse Schulze-Hardy rule normally applies, whereby the CCC varies inversely proportional to the co-ion valence.

Magnetic resonance imaging of folic acid-coated magnetite nanoparticles reflects tissue biodistribution of long-acting antiretroviral therapy.

PubMed

Li, Tianyuzi; Gendelman, Howard E; Zhang, Gang; Puligujja, Pavan; McMillan, JoEllyn M; Bronich, Tatiana K; Edagwa, Benson; Liu, Xin-Ming; Boska, Michael D

2015-01-01

Regimen adherence, systemic toxicities, and limited drug penetrance to viral reservoirs are obstacles limiting the effectiveness of antiretroviral therapy (ART). Our laboratory's development of the monocyte-macrophage-targeted long-acting nanoformulated ART (nanoART) carriage provides a novel opportunity to simplify drug-dosing regimens. Progress has nonetheless been slowed by cumbersome, but required, pharmacokinetic (PK), pharmacodynamics, and biodistribution testing. To this end, we developed a small magnetite ART (SMART) nanoparticle platform to assess antiretroviral drug tissue biodistribution and PK using magnetic resonance imaging (MRI) scans. Herein, we have taken this technique a significant step further by determining nanoART PK with folic acid (FA) decorated magnetite (ultrasmall superparamagnetic iron oxide [USPIO]) particles and by using SMART particles. FA nanoparticles enhanced the entry and particle retention to the reticuloendothelial system over nondecorated polymers after systemic administration into mice. These data were seen by MRI testing and validated by comparison with SMART particles and direct evaluation of tissue drug levels after nanoART. The development of alendronate (ALN)-coated magnetite thus serves as a rapid initial screen for the ability of targeting ligands to enhance nanoparticle-antiretroviral drug biodistribution, underscoring the value of decorated magnetite particles as a theranostic tool for improved drug delivery.

From oleic acid-capped iron oxide nanoparticles to polyethyleneimine-coated single-particle magnetofectins

NASA Astrophysics Data System (ADS)

Cruz-Acuña, Melissa; Maldonado-Camargo, Lorena; Dobson, Jon; Rinaldi, Carlos

2016-09-01

Various inorganic nanoparticle designs have been developed and used as non-viral gene carriers. Magnetic gene carriers containing polyethyleneimine (PEI), a well-known transfection agent, have been shown to improve DNA transfection speed and efficiency in the presence of applied magnetic field gradients that promote particle-cell interactions. Here we report a method to prepare iron oxide nanoparticles conjugated with PEI that: preserves the narrow size distribution of the nanoparticles, conserves magnetic properties throughout the process, and results in efficient transfection. We demonstrate the ability of the particles to electrostatically bind with DNA and transfect human cervical cancer (HeLa) cells by the use of an oscillating magnet array. Their transfection efficiency is similar to that of Lipofectamine 2000™, a commercial transfection reagent. PEI-coated particles were subjected to acidification, and acidification in the presence of salts, before DNA binding. Results show that although these pre-treatments did not affect the ability of particles to bind DNA they did significantly enhanced transfection efficiency. Finally, we show that these magnetofectins (PEI-MNP/DNA) complexes have no effect on the viability of cells at the concentrations used in the study. The systematic preparation of magnetic vectors with uniform physical and magnetic properties is critical to progressing this non-viral transfection technology.

The ALTEA/ALTEINO projects: studying functional effects of microgravity and cosmic radiation

NASA Technical Reports Server (NTRS)

Narici, L.; Belli, F.; Bidoli, V.; Casolino, M.; De Pascale, M. P.; Di Fino, L.; Furano, G.; Modena, I.; Morselli, A.; Picozza, P.;

Magnetic resonance imaging of folic acid-coated magnetite nanoparticles reflects tissue biodistribution of long-acting antiretroviral therapy

PubMed Central

Li, Tianyuzi; Gendelman, Howard E; Zhang, Gang; Puligujja, Pavan; McMillan, JoEllyn M; Bronich, Tatiana K; Edagwa, Benson; Liu, Xin-Ming; Boska, Michael D

2015-01-01

Regimen adherence, systemic toxicities, and limited drug penetrance to viral reservoirs are obstacles limiting the effectiveness of antiretroviral therapy (ART). Our laboratory’s development of the monocyte-macrophage-targeted long-acting nanoformulated ART (nanoART) carriage provides a novel opportunity to simplify drug-dosing regimens. Progress has nonetheless been slowed by cumbersome, but required, pharmacokinetic (PK), pharmacodynamics, and biodistribution testing. To this end, we developed a small magnetite ART (SMART) nanoparticle platform to assess antiretroviral drug tissue biodistribution and PK using magnetic resonance imaging (MRI) scans. Herein, we have taken this technique a significant step further by determining nanoART PK with folic acid (FA) decorated magnetite (ultrasmall superparamagnetic iron oxide [USPIO]) particles and by using SMART particles. FA nanoparticles enhanced the entry and particle retention to the reticuloendothelial system over nondecorated polymers after systemic administration into mice. These data were seen by MRI testing and validated by comparison with SMART particles and direct evaluation of tissue drug levels after nanoART. The development of alendronate (ALN)-coated magnetite thus serves as a rapid initial screen for the ability of targeting ligands to enhance nanoparticle-antiretroviral drug biodistribution, underscoring the value of decorated magnetite particles as a theranostic tool for improved drug delivery. PMID:26082630

Sintering and Microstructure of BaTiO3 Nano Particles Synthesized by Molten Salt Method.

PubMed

Lee, Chang-Hyun; Shin, Hyo-Soon; Yeo, Dong-Hun; Ha, Gook-Hyun; Nahm, Sahn

2016-05-01

In order to establish thinner dielectric layers in thick film electronic components such as MLCC (Multilayer ceramic capacitor), BaTiO3 nanoparticles have been utilized. However, studies on the synthesis of nanoparticles smaller than 20 nm, the characteristics of the BaTiO3 powder, and the powder's sintering are lacking. Therefore, this paper aims to synthesize BaTiO3 particles smaller than 20 nm by using the molten salt method and evaluate the microstructure and dielectric properties by varying the sintering temperature from 750 degrees C to 1200 degrees C. Through the molten salt method and by using KOH-KCl mixed salt, 20 nm BaTiO3 powder was synthesized at a low temperature of 150 degrees C. Sintering the pellets formed from the synthesized 20 nm BaTiO3 nano powder led to the observation of an unusual phenomenon where the particles grew to approximate sizes below 850 degrees C where densification progressed. At sintering temperatures above 950 degrees C, particles that expanded into rod shapes were observed and these particles were identified to be unreacted TiO2 based on the results of the EDX (Energy Dispersive X-ray Spectroscopy) analysis and phase analysis results.

The ALTEA/ALTEINO projects: studying functional effects of microgravity and cosmic radiation.

PubMed

Narici, L; Belli, F; Bidoli, V; Casolino, M; De Pascale, M P; Di Fino, L; Furano, G; Modena, I; Morselli, A; Picozza, P; Reali, E; Rinaldi, A; Ruggieri, D; Sparvoli, R; Zaconte, V; Sannita, W G; Carozzo, S; Licoccia, S; Romagnoli, P; Traversa, E; Cotronei, V; Vazquez, M; Miller, J; Salnitskii, V P; Shevchenko, O I; Petrov, V P; Trukhanov, K A; Galper, A; Khodarovich, A; Korotkov, M G; Popov, A; Vavilov, N; Avdeev, S; Boezio, M; Bonvicini, W; Vacchi, A; Zampa, N; Mazzenga, G; Ricci, M; Spillantini, P; Castellini, G; Vittori, R; Carlson, P; Fuglesang, C; Schardt, D

2004-01-01

The ALTEA project investigates the risks of functional brain damage induced by particle radiation in space. A modular facility (the ALTEA facility) is being implemented and will be operated in the International Space Station (ISS) to record electrophysiological and behavioral descriptors of brain function and to monitor their time dynamics and correlation with particles and space environment. The focus of the program will be on abnormal visual perceptions (often reported as "light flashes" by astronauts) and the impact on retinal and brain visual structures of particle in microgravity conditions. The facility will be made available to the international scientific community for human neurophysiological, electrophysiological and psychophysics experiments, studies on particle fluxes, and dosimetry. A precursor of ALTEA (the 'Alteino' project) helps set the experimental baseline for the ALTEA experiments, while providing novel information on the radiation environment onboard the ISS and on the brain electrophysiology of the astronauts during orbital flights. Alteino was flown to the ISS on the Soyuz TM34 as part of mission Marco Polo. Controlled ground experiments using mice and accelerator beams complete the experimental strategy of ALTEA. We present here the status of progress of the ALTEA project and preliminary results of the Alteino study on brain dynamics, particle fluxes and abnormal visual perceptions. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

Direct experimental visualization of the global Hamiltonian progression of two-dimensional Lagrangian flow topologies from integrable to chaotic state.

PubMed

Baskan, O; Speetjens, M F M; Metcalfe, G; Clercx, H J H

2015-10-01

Countless theoretical/numerical studies on transport and mixing in two-dimensional (2D) unsteady flows lean on the assumption that Hamiltonian mechanisms govern the Lagrangian dynamics of passive tracers. However, experimental studies specifically investigating said mechanisms are rare. Moreover, they typically concern local behavior in specific states (usually far away from the integrable state) and generally expose this indirectly by dye visualization. Laboratory experiments explicitly addressing the global Hamiltonian progression of the Lagrangian flow topology entirely from integrable to chaotic state, i.e., the fundamental route to efficient transport by chaotic advection, appear non-existent. This motivates our study on experimental visualization of this progression by direct measurement of Poincaré sections of passive tracer particles in a representative 2D time-periodic flow. This admits (i) accurate replication of the experimental initial conditions, facilitating true one-to-one comparison of simulated and measured behavior, and (ii) direct experimental investigation of the ensuing Lagrangian dynamics. The analysis reveals a close agreement between computations and observations and thus experimentally validates the full global Hamiltonian progression at a great level of detail.

Sensing of Immature Particles Produced by Dengue Virus Infected Cells Induces an Antiviral Response by Plasmacytoid Dendritic Cells

PubMed Central

Hillaire, Marine L. B.; Dejnirattisai, Wanwisa; Mongkolsapaya, Juthathip; Screaton, Gavin R.; Davidson, Andrew D.; Dreux, Marlène

2014-01-01

Dengue virus (DENV) is the leading cause of mosquito-borne viral illness and death in humans. Like many viruses, DENV has evolved potent mechanisms that abolish the antiviral response within infected cells. Nevertheless, several in vivo studies have demonstrated a key role of the innate immune response in controlling DENV infection and disease progression. Here, we report that sensing of DENV infected cells by plasmacytoid dendritic cells (pDCs) triggers a robust TLR7-dependent production of IFNα, concomitant with additional antiviral responses, including inflammatory cytokine secretion and pDC maturation. We demonstrate that unlike the efficient cell-free transmission of viral infectivity, pDC activation depends on cell-to-cell contact, a feature observed for various cell types and primary cells infected by DENV, as well as West Nile virus, another member of the Flavivirus genus. We show that the sensing of DENV infected cells by pDCs requires viral envelope protein-dependent secretion and transmission of viral RNA. Consistently with the cell-to-cell sensing-dependent pDC activation, we found that DENV structural components are clustered at the interface between pDCs and infected cells. The actin cytoskeleton is pivotal for both this clustering at the contacts and pDC activation, suggesting that this structural network likely contributes to the transmission of viral components to the pDCs. Due to an evolutionarily conserved suboptimal cleavage of the precursor membrane protein (prM), DENV infected cells release uncleaved prM containing-immature particles, which are deficient for membrane fusion function. We demonstrate that cells releasing immature particles trigger pDC IFN response more potently than cells producing fusion-competent mature virus. Altogether, our results imply that immature particles, as a carrier to endolysosome-localized TLR7 sensor, may contribute to regulate the progression of dengue disease by eliciting a strong innate response. PMID:25340500

Progress Towards Identifying and Quantifying the Organic Ice Nucleating Particles in Soils and Aerosols

NASA Astrophysics Data System (ADS)

Hill, T. C. J.; DeMott, P. J.; Fröhlich-Nowoisky, J.; Tobo, Y.; Suski, K. J.; Levin, E. J.; Kreidenweis, S. M.; Franc, G. D.

2014-12-01

Soil and plant surfaces emit ice nucleating particles (INP) to the atmosphere, especially when disturbed by wind, harvesting, rain or fire. Organic (biogenic) INP are abundant in most soils and dominate the population that nucleate >-15°C. For example, the sandy topsoil of sagebrush shrubland, a widespread ecotype prone to wind erosion after fire, contains ~106 organic INP g-1 at -6°C. The relevance of organic INP may also extend to colder temperatures than previously thought: Particles of soil organic matter (SOM) have been shown to be more important than mineral particles for the ice nucleating ability of agricultural soil dusts to -34°C. While the abundance of ice nucleation active (INA) bacteria on plants has been established, the identity of the organic INP in and emitted by soils remains a 40-year-old mystery. The need to understand their production and release is highlighted by recent findings that INA bacteria (measured with qPCR) account for few, if any, of the warm-temperature organic INP that predominate in boundary layer aerosols and snow; organic INP lofted with soil dusts seem a likely source. The complexity of SOM hinders its investigation. It contains decomposing plant materials, a diverse microbial and microfaunal community, humus, and inert organic matter. All are biochemically complex and all may contain ice nucleating constituents, either by design or by chance. Indeed the smoothness of the INP temperature spectra of soils is indicative of numerous, overlapping distributions of INP. We report recent progress in identifying and quantifying the organic INP in soils and boundary layer aerosols representative of West Central U.S. ecosystems, and how their characteristics may affect their dispersal. Chemical, enzymatic and DNA-based tests were used to assess contributions of INP from plant tissues, INA bacteria, INA fungi, organic crystals, monolayers of aliphatic alcohols, carbohydrates, and humic substances, while heat- and peroxide-based tests were used to estimate total organic INP abundance.

Towards testing quantum physics in deep space

NASA Astrophysics Data System (ADS)

Kaltenbaek, Rainer

2016-07-01

MAQRO is a proposal for a medium-sized space mission to use the unique environment of deep space in combination with novel developments in space technology and quantum technology to test the foundations of physics. The goal is to perform matter-wave interferometry with dielectric particles of up to 10^{11} atomic mass units and testing for deviations from the predictions of quantum theory. Novel techniques from quantum optomechanics with optically trapped particles are to be used for preparing the test particles for these experiments. The core elements of the instrument are placed outside the spacecraft and insulated from the hot spacecraft via multiple thermal shields allowing to achieve cryogenic temperatures via passive cooling and ultra-high vacuum levels by venting to deep space. In combination with low force-noise microthrusters and inertial sensors, this allows realizing an environment well suited for long coherence times of macroscopic quantum superpositions and long integration times. Since the original proposal in 2010, significant progress has been made in terms of technology development and in refining the instrument design. Based on these new developments, we submitted/will submit updated versions of the MAQRO proposal in 2015 and 2016 in response to Cosmic-Vision calls of ESA for a medium-sized mission. A central goal has been to address and overcome potentially critical issues regarding the readiness of core technologies and to provide realistic concepts for further technology development. We present the progress on the road towards realizing this ground-breaking mission harnessing deep space in novel ways for testing the foundations of physics, a technology pathfinder for macroscopic quantum technology and quantum optomechanics in space.

Fundus autofluorescence and fate of glycoxidized particles injected into subretinal space in rabbit age-related macular degeneration model.

PubMed

Hirata, Megumi; Yasukawa, Tsutomu; Wiedemann, Peter; Kimura, Erika; Kunou, Noriyuki; Eichler, Wolfram; Takase, Ayae; Sato, Rina; Ogura, Yuichiro

2009-07-01

Abnormal fundus autofluorescence (FAF) is associated with the incidence or progression of dry and wet age-related macular degeneration (AMD). We previously developed a rabbit AMD model with drusen and type-1 choroidal neovascularization (CNV) that mimics the accumulation of lipofuscin using artificial glycoxidized particles. The objective of the current study was to investigate in vitro effects of glycoxidized particles on retinal pigment epithelial (RPE) cells, and the FAF and fate of injected particles in this model. Glycoxidized particles were prepared by a 4-day incubation of water-in-oil emulsions of serum albumin and glycolaldehyde to allow glycoxidation and consequent cross-linking. After particles were added in the culture medium of confluent human RPE cells, cell viability, adhesion activity, and proliferation activity were assessed by cell counting. In anesthetized rabbits, 250 microg of glycoxidized particles were injected into the subretinal space to induce experimental AMD. FAF measurement and angiography with sodium fluorescein and indocyanine green were performed periodically using the Heidelberg Retina Angiograph 2 (HRA2). The eyes enucleated, and the lung and the spleen, excised at week 4 or 12, were histologically evaluated by light and fluorescence microscopy. Glycoxidized particles phagocytosed did not impair the cell viability, adhesion, and proliferation of RPE cells, as compared with RPE cells in controls. HRA2 showed different patterns of abnormal FAF in the area with the implanted glycoxidized particles, similar to pathological FAF patterns in aging human eyes with or without AMD. Histologic examination showed accumulated glycoxidized particles and large lipofuscin granules with green autofluorescence in and under the RPE and at the margins of or beneath drusen, possibly associated with abnormal FAF. In addition, some particles were detected in the lung and the spleen. Glycoxidized particles phagocytosed might stay in RPE cells without any acute biological reaction. Our rabbit model of AMD simulated abnormal FAF patterns observed in aging human eyes with or without AMD. Glycoxidized particles phagocytosed by RPE cells could be deposited on Bruch's membrane in rabbits, possibly excreted in part into choroidal circulation. This model may be useful for understanding various patterns of abnormal FAF histologically, and for elucidating the pathogenesis of AMD.

Advanced analysis of polymer emulsions: Particle size and particle size distribution by field-flow fractionation and dynamic light scattering.

PubMed

Makan, Ashwell C; Spallek, Markus J; du Toit, Madeleine; Klein, Thorsten; Pasch, Harald

2016-04-15

Field flow fractionation (FFF) is an advanced fractionation technique for the analyses of very sensitive particles. In this study, different FFF techniques were used for the fractionation and analysis of polymer emulsions/latexes. As model systems, a pure acrylic emulsion and emulsions containing titanium dioxide were prepared and analyzed. An acrylic emulsion polymerization was conducted, continuously sampled from the reactor and subsequently analyzed to determine the particle size, radius of gyration in specific, of the latex particles throughout the polymerization reaction. Asymmetrical flow field-flow fractionation (AF4) and sedimentation field-flow fractionation (SdFFF), coupled to a multidetector system, multi-angle laser light scattering (MALLS), ultraviolet (UV) and refractive index (RI), respectively, were used to investigate the evolution of particle sizes and particle size distributions (PSDs) as the polymerization progressed. The obtained particle sizes were compared against batch-mode dynamic light scattering (DLS). Results indicated differences between AF4 and DLS results due to DLS taking hydration layers into account, whereas both AF4 and SdFFF were coupled to MALLS detection, hence not taking the hydration layer into account for size determination. SdFFF has additional separation capabilities with a much higher resolution compared to AF4. The calculated radii values were 5 nm larger for SdFFF measurements for each analyzed sample against the corresponding AF4 values. Additionally a low particle size shoulder was observed for SdFFF indicating bimodality in the reactor very early during the polymerization reaction. Furthermore, different emulsions were mixed with inorganic species used as additives in cosmetics and coatings such as TiO2. These complex mixtures of species were analyzed to investigate the retention and particle interaction behavior under different AF4 experimental conditions, such as the mobile phase. The AF4 system was coupled online to inductively coupled plasma mass spectrometry (ICP-MS) for elemental speciation and identification of the inorganic additive. SdFFF had a larger separation power to distinguish different particle size populations whereas AF4 had the capability of separating the organic particles and inorganic TiO2 particles, with high resolution. Copyright © 2016 Elsevier B.V. All rights reserved.

Laser-driven particle acceleration for radiobiology and radiotherapy: where we are and where we are going

NASA Astrophysics Data System (ADS)

Giulietti, Antonio

2017-05-01

Radiation therapy of tumors progresses continuously and so do devices, sharing a global market of about $ 4 billions, growing at an annual rate exceeding 5%. Most of the progress involves tumor targeting, multi-beam irradiation, reduction of damage on healthy tissues and critical organs, dose fractioning. This fast-evolving scenario is the moving benchmark for the progress of the laser-based accelerators towards clinical uses. As for electrons, both energy and dose requested by radiotherapy are available with plasma accelerators driven by lasers in the power range of tens of TW but several issues have still to be faced before getting a prototype device for clinical tests. They include capability of varying electron energy, stability of the process, reliability for medical users. On the other side hadron therapy, presently applied to a small fraction of cases but within an exponential growth, is a primary option for the future. With such a strong motivation, research on laser-based proton/ion acceleration has been supported in the last decade in order to get performances suitable to clinical standards. None of these performances has been achieved so far with laser techniques. In the meantime a rich crop of data have been obtained in radiobiological experiments performed with beams of particles produced with laser techniques. It is quite significant however that most of the experiments have been performed moving bio samples to laser labs, rather moving laser equipment to bio labs or clinical contexts. This give us the measure that laser community cannot so far provide practical devices usable by non-laser people.

Physics Division progress report, January 1, 1984-September 30, 1986

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

Keller, W.E.

1987-10-01

This report provides brief accounts of significant progress in development activities and research results achieved by Physics Division personnel during the period January 1, 1984, through September 31, 1986. These efforts are representative of the three main areas of experimental research and development in which the Physics Division serves Los Alamos National Laboratory's and the Nation's needs in defense and basic sciences: (1) defense physics, including the development of diagnostic methods for weapons tests, weapon-related high-energy-density physics, and programs supporting the Strategic Defense Initiative; (2) laser physics and applications, especially to high-density plasmas; and (3) fundamental research in nuclear andmore » particle physics, condensed-matter physics, and biophysics. Throughout the report, emphasis is placed on the design, construction, and application of a variety of advanced, often unique, instruments and instrument systems that maintain the Division's position at the leading edge of research and development in the specific fields germane to its mission. A sampling of experimental systems of particular interest would include the relativistic electron-beam accelerator and its applications to high-energy-density plasmas; pulsed-power facilities; directed energy weapon devices such as free-electron lasers and neutral-particle-beam accelerators; high-intensity ultraviolet and x-ray beam lines at the National Synchrotron Light Source (at Brookhaven National Laboratory); the Aurora KrF ultraviolet laser system for projected use as an inertial fusion driver; antiproton physics facility at CERN; and several beam developments at the Los Alamos Meson Physics Facility for studying nuclear, condensed-matter, and biological physics, highlighted by progress in establishing the Los Alamos Neutron Scattering Center.« less

Particle damage sources for fused silica optics and their mitigation on high energy laser systems.

PubMed

Bude, J; Carr, C W; Miller, P E; Parham, T; Whitman, P; Monticelli, M; Raman, R; Cross, D; Welday, B; Ravizza, F; Suratwala, T; Davis, J; Fischer, M; Hawley, R; Lee, H; Matthews, M; Norton, M; Nostrand, M; VanBlarcom, D; Sommer, S

2017-05-15

High energy laser systems are ultimately limited by laser-induced damage to their critical components. This is especially true of damage to critical fused silica optics, which grows rapidly upon exposure to additional laser pulses. Much progress has been made in eliminating damage precursors in as-processed fused silica optics (the advanced mitigation process, AMP3), and very high damage resistance has been demonstrated in laboratory studies. However, the full potential of these improvements has not yet been realized in actual laser systems. In this work, we explore the importance of additional damage sources-in particular, particle contamination-for fused silica optics fielded in a high-performance laser environment, the National Ignition Facility (NIF) laser system. We demonstrate that the most dangerous sources of particle contamination in a system-level environment are laser-driven particle sources. In the specific case of the NIF laser, we have identified the two important particle sources which account for nearly all the damage observed on AMP3 optics during full laser operation and present mitigations for these particle sources. Finally, with the elimination of these laser-driven particle sources, we demonstrate essentially damage free operation of AMP3 fused silica for ten large optics (a total of 12,000 cm 2 of beam area) for shots from 8.6 J/cm 2 to 9.5 J/cm 2 of 351 nm light (3 ns Gaussian pulse shapes). Potentially many other pulsed high energy laser systems have similar particle sources, and given the insight provided by this study, their identification and elimination should be possible. The mitigations demonstrated here are currently being employed for all large UV silica optics on the National Ignition Facility.