WorldWideScience

Sample records for antineutrino reactions

  1. Study of charged current reactions induced by muon antineutrinos

    International Nuclear Information System (INIS)

    Huss, D.

    1979-07-01

    We present in this work a study of antineutrino reactions on light targets. We have used the Gargamelle cloud chamber with a propane-freon mix. In the 2 first chapters we give a brief description of the experimental setting and we present the selection criteria of the events. In the third chapter we analyse the data for the reaction anti-ν + p → μ + + n that preserves strangeness. We have deduced the values of the axial (M A ) and vector (M V ) form factors: M A = (O.92 ± 0.08) GeV and M V = (0.86 ± 0.04) GeV. In the fourth chapter we study reactions in which strange particles appear (ΔS = 1) and we have determined their production cross-sections. The elastic reaction: anti-ν + p → μ + + Λ is studied in a more accurate manner thanks to a 3-constraint adjustment that enables the selection of events occurring on free protons. We have deduced from our data the longitudinal, orthogonal and transverse polarization of Λ, we have got respectively P l = -0.06 ± 0.44; P p = 0.29 ± 0.41; P t 1.05 ± 0.30. We have also deduced the values of the total cross-section as a function of the incident antineutrino energy E: σ (0.27 ± 0.02)*E*10 -38 cm -2 . E has been assessed from the energy deposited in the cloud chamber and we have adjusted the cross-section with a straight line as it is expected under the assumption of scale invariance. (A.C.)

  2. Neutrino and antineutrino charge-exchange reactions on 12C

    International Nuclear Information System (INIS)

    Samana, A. R.; Krmpotic, F.; Paar, N.; Bertulani, C. A.

    2011-01-01

    We extend the formalism of weak interaction processes, obtaining new expressions for the transition rates, which greatly facilitate numerical calculations, for both neutrino-nucleus reactions and muon capture. Explicit violation of the conserved vector current hypothesis by the Coulomb field, as well as development of a sum-rule approach for inclusive cross sections, has been worked out. We have done a thorough study of exclusive (ground-state) properties of 12 B and 12 N within the projected quasiparticle random phase approximation (PQRPA). Good agreement with experimental data achieved in this way put into evidence the limitations of the standard RPA and QRPA models, which come from the inability of the RPA to open the p 3/2 shell and from the nonconservation of the number of particles in the QRPA. The inclusive neutrino/antineutrino (ν/ν-tilde) reactions 12 C(ν,e - ) 12 N and 12 C(ν-tilde,e + ) 12 B are calculated within both the PQRPA and the relativistic QRPA. It is found that (i) the magnitudes of the resulting cross sections are close to the sum-rule limit at low energy, but significantly smaller than this limit at high energies, for both ν and ν-tilde; (ii) they increase steadily when the size of the configuration space is augmented, particularly for ν/ν-tilde energies >200 MeV; and (iii) they converge for sufficiently large configuration space and final-state spin. The quasi-elastic 12 C(ν,μ - ) 12 N cross section recently measured in the MiniBooNE experiment is briefly discussed. We study the decomposition of the inclusive cross section based on the degree of forbiddenness of different multipoles. A few words are dedicated to the ν/ν-tilde- 12 C charge-exchange reactions related to astrophysical applications.

  3. Calculation of reactor antineutrino spectra in TEXONO

    CERN Document Server

    Chen Dong Liang; Mao Ze Pu; Wong, T H

    2002-01-01

    In the low energy reactor antineutrino physics experiments, either for the researches of antineutrino oscillation and antineutrino reactions, or for the measurement of abnormal magnetic moment of antineutrino, the flux and the spectra of reactor antineutrino must be described accurately. The method of calculation of reactor antineutrino spectra was discussed in detail. Furthermore, based on the actual circumstances of NP2 reactors and the arrangement of detectors, the flux and the spectra of reactor antineutrino in TEXONO were worked out

  4. Study of neutral current reactions with production of a pion induced by muon antineutrinos

    International Nuclear Information System (INIS)

    Guyonnet, J.L.

    1981-03-01

    In this work we have studied the 4 production reactions of a pion induced by muon anti-neutrino collisions with nucleons: anti-ν μ p → anti-ν μ pπ 0 or anti-ν μ nπ + and anti-ν μ n → anti-ν μ nπ 0 or anti-ν μ pπ - . We have processed experimental data from the Gargamelle cloud chamber to assess the pion production cross-sections. Our results are consistent with the theoretical predictions of the Adler model and of the Fogli and Nardulli model within the framework of the Weinberg and Salam unified theory. As for the isospin structure of the weak hadronic neutral current, the iso-vectorial component is highlighted in the invariant mass spectra in the channels pπ 0 and pπ - . Our results show that the isospin structure is not purely isoscalar or purely iso-vectorial but rather a mix of I = 0 and I = 1. We confirm that the sign of the product of the 2 coupling constants u L *d L is negative. (A.C.)

  5. The reactor antineutrino anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Haser, Julia; Buck, Christian; Lindner, Manfred [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

    2016-07-01

    Major discoveries were made in the past few years in the field of neutrino flavour oscillation. Nuclear reactors produce a clean and intense flux of electron antineutrinos and are thus an essential neutrino source for the determination of oscillation parameters. Most currently the reactor antineutrino experiments Double Chooz, Daya Bay and RENO have accomplished to measure θ{sub 13}, the smallest of the three-flavour mixing angles. In the course of these experiments two anomalies emerged: (1) the reanalysis of the reactor predictions revealed a deficit in experimentally observed antineutrino flux, known as the ''reactor antineutrino anomaly''. (2) The high precision of the latest generation of neutrino experiments resolved a spectral shape distortion relative to the expected energy spectra. Both puzzles are yet to be solved and triggered new experimental as well as theoretical studies, with the search for light sterile neutrinos as most popular explanation for the flux anomaly. This talk outlines the two reactor antineutrino anomalies. Discussing possible explanations for their occurrence, recent and upcoming efforts to solve the reactor puzzles are highlighted.

  6. Towards Compact Antineutrino Detectors for Safeguarding Nuclear Reactors

    International Nuclear Information System (INIS)

    Meijer, R.J. de; Smit, F.D.; Woertche, H.J.

    2010-01-01

    research programs aim at developing scintillator materials, with a high flame point and weak or no quenching. Moreover we require (Pulse Shape Discrimination) PSD to differentiate between gammas and alphas and Bayesian filtering for background suppression. The second method is triggered by a recent paper indicating an effect of neutrinos on beta- decay. We are investigating the 'mirror' reaction of antineutrinos on beta+ decay. Although we have reduced the effect already by two orders of magnitude, the present upper limit would still allow antineutrino-flux monitoring at nuclear power reactors. (author)

  7. KamLAND and Solar Antineutrino Spectrum

    CERN Document Server

    Chauhan, B C; Torrente-Lujan, E; Chauhan, Bhag C.; Pulido, Joao

    2004-01-01

    We use the recent KamLAND observations to predict the solar antineutrino spectrum at some confidence limits. We find that a scaling of the antineutrino probability with respect to the magnetic field profile --in the sense that the same probability function can be reproduced by any profile with a suitable peak field value-- can be utilised to obtain a general shape of the solar antineutrino spectrum. This scaling and the upper bound on the solar antineutrino event rate, that can be derived from the data, lead to: 1) an upper bound on the solar antineutrino flux, 2) the prediction of their energy spectrum, as the normalisation of the spectrum can be obtained from the total number of antineutrino events recorded in the experiment. We get $\\phi_{\\bar\

  8. Daya Bay Antineutrino Detector Gas System

    OpenAIRE

    Band, H. R.; Cherwinka, J. J.; Chu, M-C.; Heeger, K. M.; Kwok, M. W.; Shih, K.; Wise, T.; Xiao, Q.

    2012-01-01

    The Daya Bay Antineutrino Detector gas system is designed to protect the liquid scintillator targets of the antineutrino detectors against degradation and contamination from exposure to ambient laboratory air. The gas system is also used to monitor the leak tightness of the antineutrino detector assembly. The cover gas system constantly flushes the gas volumes above the liquid scintillator with dry nitrogen to minimize oxidation of the scintillator over the five year lifetime of the experimen...

  9. Antineutrino Oscillations in the Atmospheric Sector

    Energy Technology Data Exchange (ETDEWEB)

    Himmel, Alexander I. [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2011-05-01

    This thesis presents measurements of the oscillations of muon antineutrinos in the atmospheric sector, where world knowledge of antineutrino oscillations lags well behind the knowledge of neutrinos, as well as a search for vμ → $\\bar{v}$μ transitions. Differences between neutrino and antineutrino oscillations could be a sign of physics beyond the Standard Model, including non-standard matter interactions or the violation of CPT symmetry. These measurements leverage the sign-selecting capabilities of the magnetized steel-scintillator MINOS detectors to analyze antineutrinos from the NuMI beam, both when it is in neutrino-mode and when it is in antineutrino-mode. Antineutrino oscillations are observed at |Δ$\\bar{m}$atm 2| = (3.36-0.40+0.46(stat) ± 0.06(syst)) x 10-3 eV2 and sin2(2$\\bar{θ}$23) = 0.860-0.12+0.11(stat) ± 0.01(syst). The oscillation parameters measured for antineutrinos and those measured by MINOS for neutrinos differ by a large enough margin that the chance of obtaining two values as discrepant as those observed is only 2%, assuming the two measurements arise from the same underlying mechanism, with the same parameter values. No evidence is seen for neutrino-to-antineutrino transitions.

  10. Antineutrino Monitoring of Spent Nuclear Fuel

    Science.gov (United States)

    Brdar, Vedran; Huber, Patrick; Kopp, Joachim

    2017-11-01

    Military and civilian applications of nuclear energy have left a significant amount of spent nuclear fuel over the past 70 years. Currently, in many countries worldwide, the use of nuclear energy is on the rise. Therefore, the management of highly radioactive nuclear waste is a pressing issue. In this paper, we explore antineutrino detectors as a tool for monitoring and safeguarding nuclear-waste material. We compute the flux and spectrum of antineutrinos emitted by spent nuclear fuel elements as a function of time, and we illustrate the usefulness of antineutrino detectors in several benchmark scenarios. In particular, we demonstrate how a measurement of the antineutrino flux can help to reverify the contents of a dry storage cask in case the monitoring chain by conventional means gets disrupted. We then comment on the usefulness of antineutrino detectors at long-term storage facilities such as Yucca mountain. Finally, we put forward antineutrino detection as a tool in locating underground "hot spots" in contaminated areas such as the Hanford site in Washington state.

  11. Workshop applied antineutrino physics 2007

    International Nuclear Information System (INIS)

    Akiri, T.; Andrieu, B.; Anjos, J.; Argyriades, J.; Barouch, G.; Bernstein, A.; Bersillon, O.; Besida, O.; Bowden, N.; Cabrera, A.; Calmet, D.; Collar, J.; Cribier, M.; Kerret, H. de; Meijer, R. de; Dudziak, F.; Enomoto, S.; Fallot, M.; Fioni, G.; Fiorentini, G.; Gale, Ph.; Georgadze, A.; Giot, L.; Gonin, M.; Guillon, B.; Henson, C.; Jonkmans, G.; Kanamaru, S.; Kawasaki, T.; Kornoukhov, V.; Lasserre, Th.; Learned, J.G.; Lefebvre, J.; Letourneau, A.; Lhillier, D.; Lindner, M.; Lund, J.; Mantovani, F.; Mcdonough, B.; Mention, G.; Monteith, A.; Motta, D.; Mueller, Th.; Oberauer, L.; Obolensky, M.; Odrzywolek, A.; Petcov, S.; Porta, A.; Queval, R.; Reinhold, B.; Reyna, D.; Ridikas, D.; Sadler, L.; Schoenert, St.; Sida, J.L.; Sinev, V.; Suekane, F.; Suvorov, Y.; Svoboda, R.; Tang, A.; Tolich, N.; Tolich, K.; Vanka, S.; Vignaud, D.; Volpe, Ch.; Wong, H.

    2007-01-01

    The 'Applied Antineutrino Physics 2007' workshop is the fourth international meeting devoted to the opening of the neutrino physics to more applied fields, such as geophysics and geochemistry, nuclear industry, as well as the nonproliferation. This meeting highlights the world efforts already engaged to exploit the single characteristics of the neutrinos for the control of the production of plutonium in the civil nuclear power reactor. The potential industrial application of the measurement of the thermal power of the nuclear plants by the neutrinos is also approached. earth neutrinos were for the first time highlighted in 2002 by the KamLAND experiment. Several international efforts are currently underway to use earth neutrinos to reveal the interior of the Earth. This meeting is an opportunity to adapt the efforts of detection to the real needs of geophysicists and geochemists (sources of radiogenic heat, potassium in the court, feathers.) Finally more futuristic topics such as the detection of nuclear explosions, of low powers, are also discussed. This document gathers only the slides of the presentations

  12. Workshop applied antineutrino physics 2007

    Energy Technology Data Exchange (ETDEWEB)

    Akiri, T.; Andrieu, B.; Anjos, J.; Argyriades, J.; Barouch, G.; Bernstein, A.; Bersillon, O.; Besida, O.; Bowden, N.; Cabrera, A.; Calmet, D.; Collar, J.; Cribier, M.; Kerret, H. de; Meijer, R. de; Dudziak, F.; Enomoto, S.; Fallot, M.; Fioni, G.; Fiorentini, G.; Gale, Ph.; Georgadze, A.; Giot, L.; Gonin, M.; Guillon, B.; Henson, C.; Jonkmans, G.; Kanamaru, S.; Kawasaki, T.; Kornoukhov, V.; Lasserre, Th.; Learned, J.G.; Lefebvre, J.; Letourneau, A.; Lhillier, D.; Lindner, M.; Lund, J.; Mantovani, F.; Mcdonough, B.; Mention, G.; Monteith, A.; Motta, D.; Mueller, Th.; Oberauer, L.; Obolensky, M.; Odrzywolek, A.; Petcov, S.; Porta, A.; Queval, R.; Reinhold, B.; Reyna, D.; Ridikas, D.; Sadler, L.; Schoenert, St.; Sida, J.L.; Sinev, V.; Suekane, F.; Suvorov, Y.; Svoboda, R.; Tang, A.; Tolich, N.; Tolich, K.; Vanka, S.; Vignaud, D.; Volpe, Ch.; Wong, H

    2007-07-01

    The 'Applied Antineutrino Physics 2007' workshop is the fourth international meeting devoted to the opening of the neutrino physics to more applied fields, such as geophysics and geochemistry, nuclear industry, as well as the nonproliferation. This meeting highlights the world efforts already engaged to exploit the single characteristics of the neutrinos for the control of the production of plutonium in the civil nuclear power reactor. The potential industrial application of the measurement of the thermal power of the nuclear plants by the neutrinos is also approached. earth neutrinos were for the first time highlighted in 2002 by the KamLAND experiment. Several international efforts are currently underway to use earth neutrinos to reveal the interior of the Earth. This meeting is an opportunity to adapt the efforts of detection to the real needs of geophysicists and geochemists (sources of radiogenic heat, potassium in the court, feathers.) Finally more futuristic topics such as the detection of nuclear explosions, of low powers, are also discussed. This document gathers only the slides of the presentations.

  13. Daya Bay Antineutrino Detector gas system

    Science.gov (United States)

    Band, H. R.; Cherwinka, J. J.; Chu, M.-C.; Heeger, K. M.; Kwok, M. W.; Shih, K.; Wise, T.; Xiao, Q.

    2012-11-01

    The Daya Bay Antineutrino Detector gas system is designed to protect the liquid scintillator targets of the antineutrino detectors against degradation and contamination from exposure to ambient laboratory air. The gas system is also used to monitor the leak tightness of the antineutrino detector assembly. The cover gas system constantly flushes the gas volumes above the liquid scintillator with dry nitrogen to minimize oxidation of the scintillator over the five year lifetime of the experiment. This constant flush also prevents the infiltration of radon or other contaminants into these detecting liquids keeping the internal backgrounds low. Since the Daya Bay antineutrino detectors are immersed in the large water pools of the muon veto system, other gas volumes are needed to protect vital detector cables or gas lines. These volumes are also purged with dry gas. Return gas is monitored for oxygen content and humidity to provide early warning of potentially damaging leaks. The design and performance of the Daya Bay Antineutrino Detector gas system is described.

  14. A Direction-Sensitive Detector for Electron Antineutrinos

    Science.gov (United States)

    Brooks, F. D.; Drosg, M.; Smit, F. D.

    2011-12-01

    A modular design is proposed for an electron antineutrino detector based on boron-doped liquid scintillator. Tests have been carried out on small detector systems using neutrons to simulate the antineutrino detection signature. Results from these tests are reported, and the possibility of using a larger system of similar design to detect reactor antineutrinos is discussed.

  15. Applied Anti-neutrino Physics 2013

    CERN Document Server

    2013-01-01

    This year, the 9th annual Applied Antineutrino Physics Workshop will be hosted by Sejong University, at the COEX conference center in Seoul South Korea. The workshop will be held on November 1(Friday) - 2(Saturday), 2013. Conveniently for many travelers, it takes place directly after and at the same venue as the 2013 IEEE Nuclear Science Symposium (http://www.nss-mic.org/2013/NSSMain.asp) Applied Antineutrino Physics describes an ensemble of experimental and theoretical efforts which aim to use the antineutrino signal from nuclear reactors, and from the Earth itself, in order to address practical problems in nonproliferation and geology respectively. Since the 2004 inception of these workshops, groups worldwide have made considerable advances in defining and expanding the field, garnering interest from the International Atomic Energy Agency (IAEA), which administers the worlds most important nonproliferation regime, and from the geology/geophysics community. This meeting will focus on the current activi...

  16. Anti-neutrino disintegration of the deuteron

    International Nuclear Information System (INIS)

    Mueller, W.; Gari, M.; Max-Planck-Institut fuer Chemie

    1981-01-01

    The anti-neutrino disintegration of the deuteron (anti ν + D → anti ν + n + p and anti νsub(e) + D → + e + + n + n) is calculated using realistic two-body states. Meson-exchange currents are considered in the one-boson-exchange limit. The results are discussed as corrections to the cross sections obtained in effective range approximations. It is shown that the ratio of the cross sections (sigma - /sigma 0 ) for reactor antineutrinos is practically independent of the nuclear physics uncertainties. (orig.)

  17. Antineutrino-nucleon total cross section and ratio of antineutrino cross section on neutrons and protons

    CERN Document Server

    Erriquez, O; Bisi, V; Bonetti, S; Bullock, F W; Cavalli, D; Engel, J P; Eranzinetti, C; Escubes, B; Esten, M J; Fogli-Muciaccia, M T; Gamba, D; Guyonnet, J L; Halsteinslid, A; Henderson, R C W; Huss, D; Jones, T W; Marzari-Chiesa, A; Mauri, F; Myklebost, K; Natali, S; Nuzzo, S; Paty, M; Pullia, A; Racca, C; Ramzan, F A; Riccati, L; Riester, J L; Rognebakke, A; Rollier, M; Romero, A; Skjeggestad, O

    1979-01-01

    On a selected sample of 2171 events, observed in the heavy liquid bubble chamber Gargamelle at CERN, the charged current total cross section for antineutrino on nucleons has been determined to the laboratory energy 8 GeV. (7 refs).

  18. Present and Future Experiments in Non-equilibrium Reactor Antineutrino Energy Spectrum

    OpenAIRE

    Kopeikin, V. I.; Mikaelyan, L. A.

    2005-01-01

    Considerable efforts that have been undertaken in the recent years in low energy antineutrino experiments require further systematic investigations in line of reactor antineutrino spectroscopy as a metrological basis of these experiments. We consider some effects associated with the non-equilibrium of reactor antineutrino radiation and residual antineutrino emission from spent reactor fuel in contemporary antineutrino experiments.

  19. Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay.

    Science.gov (United States)

    An, F P; Balantekin, A B; Band, H R; Bishai, M; Blyth, S; Butorov, I; Cao, D; Cao, G F; Cao, J; Cen, W R; Chan, Y L; Chang, J F; Chang, L C; Chang, Y; Chen, H S; Chen, Q Y; Chen, S M; Chen, Y X; Chen, Y; Cheng, J H; Cheng, J; Cheng, Y P; Cherwinka, J J; Chu, M C; Cummings, J P; de Arcos, J; Deng, Z Y; Ding, X F; Ding, Y Y; Diwan, M V; Dove, J; Draeger, E; Dwyer, D A; Edwards, W R; Ely, S R; Gill, R; Gonchar, M; Gong, G H; Gong, H; Grassi, M; Gu, W Q; Guan, M Y; Guo, L; Guo, X H; Hackenburg, R W; Han, R; Hans, S; He, M; Heeger, K M; Heng, Y K; Higuera, A; Hor, Y K; Hsiung, Y B; Hu, B Z; Hu, L M; Hu, L J; Hu, T; Hu, W; Huang, E C; Huang, H X; Huang, X T; Huber, P; Hussain, G; Jaffe, D E; Jaffke, P; Jen, K L; Jetter, S; Ji, X P; Ji, X L; Jiao, J B; Johnson, R A; Kang, L; Kettell, S H; Kohn, S; Kramer, M; Kwan, K K; Kwok, M W; Kwok, T; Langford, T J; Lau, K; Lebanowski, L; Lee, J; Lei, R T; Leitner, R; Leung, K Y; Leung, J K C; Lewis, C A; Li, D J; Li, F; Li, G S; Li, Q J; Li, S C; Li, W D; Li, X N; Li, X Q; Li, Y F; Li, Z B; Liang, H; Lin, C J; Lin, G L; Lin, P Y; Lin, S K; Ling, J J; Link, J M; Littenberg, L; Littlejohn, B R; Liu, D W; Liu, H; Liu, J L; Liu, J C; Liu, S S; Lu, C; Lu, H Q; Lu, J S; Luk, K B; Ma, Q M; Ma, X Y; Ma, X B; Ma, Y Q; Martinez Caicedo, D A; McDonald, K T; McKeown, R D; Meng, Y; Mitchell, I; Monari Kebwaro, J; Nakajima, Y; Napolitano, J; Naumov, D; Naumova, E; Ngai, H Y; Ning, Z; Ochoa-Ricoux, J P; Olshevski, A; Pan, H-R; Park, J; Patton, S; Pec, V; Peng, J C; Piilonen, L E; Pinsky, L; Pun, C S J; Qi, F Z; Qi, M; Qian, X; Raper, N; Ren, B; Ren, J; Rosero, R; Roskovec, B; Ruan, X C; Shao, B B; Steiner, H; Sun, G X; Sun, J L; Tang, W; Taychenachev, D; Tsang, K V; Tull, C E; Tung, Y C; Viaux, N; Viren, B; Vorobel, V; Wang, C H; Wang, M; Wang, N Y; Wang, R G; Wang, W; Wang, W W; Wang, X; Wang, Y F; Wang, Z; Wang, Z; Wang, Z M; Wei, H Y; Wen, L J; Whisnant, K; White, C G; Whitehead, L; Wise, T; Wong, H L H; Wong, S C F; Worcester, E; Wu, Q; Xia, D M; Xia, J K; Xia, X; Xing, Z Z; Xu, J Y; Xu, J L; Xu, J; Xu, Y; Xue, T; Yan, J; Yang, C G; Yang, L; Yang, M S; Yang, M T; Ye, M; Yeh, M; Young, B L; Yu, G Y; Yu, Z Y; Zang, S L; Zhan, L; Zhang, C; Zhang, H H; Zhang, J W; Zhang, Q M; Zhang, Y M; Zhang, Y X; Zhang, Y M; Zhang, Z J; Zhang, Z Y; Zhang, Z P; Zhao, J; Zhao, Q W; Zhao, Y F; Zhao, Y B; Zheng, L; Zhong, W L; Zhou, L; Zhou, N; Zhuang, H L; Zou, J H

    2016-02-12

    This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18)  cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43)  cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.

  20. Antineutrino flux and spectrum calculation for spent nuclear fuel for the Daya Bay antineutrino experiment

    Science.gov (United States)

    Ma, X. B.; Zhao, Y. F.; Chen, Y. X.; Zhong, W. L.; An, F. P.

    2017-10-01

    The antineutrino flux from spent nuclear fuel (SNF) is an important source of uncertainty when making estimates of a reactor neutrino flux. However, to determine the contribution from SNF, sufficient data is needed such as the amount of spent fuel in the pool, the time after discharged from the reactor core, the burnup of each assembly, and the antineutrino spectrum of each isotope in the SNF. A method to calculate this contribution is proposed. A reactor simulation code verified against experimental data has been used to simulate fuel depletion by taking into account more than 2000 isotopes and fission products, the quantity of SNF in each of the six spent fuel pools, and the time variation of the antineutrino spectra after SNF discharging from the core. Results show that the SNF contribution to the total antineutrino flux is about 0.26%-0.34%, and the shutdown impact is about 20%. The SNF spectrum alters the softer part of the antineutrino spectra, and the maximum contribution from the SNF is about 3.0%. Nevertheless, there is an 18% difference between the line evaluate method and under evaluate method. In addition, non-equilibrium effects are also discussed, and the results are compatible considering the uncertainties.

  1. Antineutrino and gamma emission from the OSIRIS research reactor

    Directory of Open Access Journals (Sweden)

    Giot Lydie

    2017-01-01

    Full Text Available For the first time, the summation method has been coupled with a complete reactor model, in order to predict the antineutrino emission of a research reactor. This work, discussed in the first part of this paper, allows us to predict the low energy part of the antineutrino spectrum, evidencing the important contribution of actinides to the antineutrino emission. Experimental conditions at short distance from research reactors are challenging, because the reactor itself produces huge gamma background that induce accidental and correlated backgrounds in an antineutrino target. The understanding of this background is of utmost importance and triggered the second part of the work presented here.

  2. Reactor antineutrino detector iDREAM.

    Science.gov (United States)

    Gromov, M. B.; Lukyanchenko, G. A.; Novikova, G. J.; Obinyakov, B. A.; Oralbaev, A. Y.; Skorokhvatov, M. D.; Sukhotin, S. V.; Chepurnov, A. S.; Etenko, A. V.

    2017-09-01

    Industrial Detector for Reactor Antineutrino Monitoring (iDREAM) is a compact (≈ 3.5m 2) industrial electron antineutrino spectrometer. It is dedicated for remote monitoring of PWR reactor operational modes by neutrino method in real-time. Measurements of antineutrino flux from PWR allow to estimate a fuel mixture in active zone and to check the status of the reactor campaign for non-proliferation purposes. LAB-based gadolinium doped scintillator is exploited as a target. Multizone architecture of the detector with gamma-catcher surrounding fiducial volume and plastic muon veto above and below ensure high efficiency of IBD detection and background suppression. DAQ is based on Flash ADC with PSD discrimination algorithms while digital trigger is programmable and flexible due to FPGA. The prototype detector was started up in 2014. Preliminary works on registration Cerenkov radiation produced by cosmic muons were established with distilled water inside the detector in order to test electronic and slow control systems. Also in parallel a long-term measurements with different scintillator samples were conducted.

  3. Development of the reactor antineutrino detection technology within the iDream project

    Science.gov (United States)

    Gromov, M.; Kuznetsov, D.; Murchenko, A.; Novikova, G.; Obinyakov, B.; Oralbaev, A.; Plakitina, K.; Skorokhvatov, M.; Sukhotin, S.; Chepurnov, A.; Etenko, A.

    2017-12-01

    The iDREAM (industrial Detector for reactor antineutrino monitoring) project is aimed at remote monitoring of the operating modes of the atomic reactor on nuclear power plant to ensure a technical support of IAEA non-proliferation safeguards. The detector is a scintillator spectrometer. The sensitive volume (target) is filled with a liquid organic scintillator based on linear alkylbenzene where reactor antineutrinos will be detected via inverse beta-decay reaction. We present first results of laboratory tests after physical launch. The detector was deployed at sea level without background shielding. The number of calibrations with radioactive sources was conducted. All data were obtained by means of a slow control system which was put into operation.

  4. Reactor Monitoring with Antineutrinos - A Progress Report

    Science.gov (United States)

    Bernstein, Adam

    2012-08-01

    The Reactor Safeguards regime is the name given to a set of protocols and technologies used to monitor the consumption and production of fissile materials in nuclear reactors. The Safeguards regime is administered by the International Atomic Energy Agency (IAEA), and is an essential component of the global Treaty on Nuclear Nonproliferation, recently renewed by its 189 remaining signators. (The 190th, North Korea, withdrew from the Treaty in 2003). Beginning in Russia in the 1980s, a number of researchers worldwide have experimentally demonstrated the potential of cubic meter scale antineutrino detectors for non-intrusive real-time monitoring of fissile inventories and power output of reactors. The detectors built so far have operated tens of meters from a reactor core, outside of the containment dome, largely unattended and with remote data acquisition for an entire 1.5 year reactor cycle, and have achieved levels of sensitivity to fissile content of potential interest for the IAEA safeguards regime. In this article, I will describe the unique advantages of antineutrino detectors for cooperative monitoring, consider the prospects and benefits of increasing the range of detectability for small reactors, and provide a partial survey of ongoing global research aimed at improving near-field and far field monitoring and discovery of nuclear reactors.

  5. Long Distance Reactor Antineutrino Flux Monitoring

    Science.gov (United States)

    Dazeley, Steven; Bergevin, Marc; Bernstein, Adam

    2015-10-01

    The feasibility of antineutrino detection as an unambiguous and unshieldable way to detect the presence of distant nuclear reactors has been studied. While KamLAND provided a proof of concept for long distance antineutrino detection, the feasibility of detecting single reactors at distances greater than 100 km has not yet been established. Even larger detectors than KamLAND would be required for such a project. Considerations such as light attenuation, environmental impact and cost, which favor water as a detection medium, become more important as detectors get larger. We have studied both the sensitivity of water based detection media as a monitoring tool, and the scientific impact such detectors might provide. A next generation water based detector may be able to contribute to important questions in neutrino physics, such as supernova neutrinos, sterile neutrino oscillations, and non standard electroweak interactions (using a nearby compact accelerator source), while also providing a highly sensitive, and inherently unshieldable reactor monitoring tool to the non proliferation community. In this talk I will present the predicted performance of an experimental non proliferation and high-energy physics program. Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy, National Nuclear Security Administration under Contract DE-AC52-07NA27344. Release number LLNL-ABS-674192.

  6. Determining reactor fuel type from continuous antineutrino monitoring

    OpenAIRE

    Jaffke, Patrick; Huber, Patrick

    2016-01-01

    We investigate the ability of an antineutrino detector to determine the fuel type of a reactor. A hypothetical 5t antineutrino detector is placed 25m from the core and measures the spectral shape and rate of antineutrinos emitted by fission fragments in the core for a number of 90 day periods. Our results indicate that four major fuel types can be differentiated from the variation of fission fractions over the irradiation time with a true positive probability of detection at 95%. In addition,...

  7. Heavy quark production by neutrinos and antineutrinos

    International Nuclear Information System (INIS)

    Scott, D.M.; Tanaka, K.

    1979-01-01

    The rate for producing t- and b-quarks in, respectively, neutrino and antineutrino interactions with nucleons are estimated. Experimental quark parton distribution functions, SU(2) x SU(2) x U(1) gauge group mixing angles, and threshold suppression through rescaling are used in the calculation. The ratios to total cross sections of b-quark production by anti nu, R/sub b//sup anti nu/, and t-quark production by ν, R/sub t//sup nu/, are, respectively, R/sub b//sup anti nu/ approximately equal to 10 -4 and R/sub t//sup nu/ approximately equal to 10 -5 for an incident energy of 200 GeV. 13 references

  8. The reactor antineutrino anomaly and low energy threshold neutrino experiments

    Science.gov (United States)

    Cañas, B. C.; Garcés, E. A.; Miranda, O. G.; Parada, A.

    2018-01-01

    Short distance reactor antineutrino experiments measure an antineutrino spectrum a few percent lower than expected from theoretical predictions. In this work we study the potential of low energy threshold reactor experiments in the context of a light sterile neutrino signal. We discuss the perspectives of the recently detected coherent elastic neutrino-nucleus scattering in future reactor antineutrino experiments. We find that the expectations to improve the current constraints on the mixing with sterile neutrinos are promising. We also analyze the measurements of antineutrino scattering off electrons from short distance reactor experiments. In this case, the statistics is not competitive with inverse beta decay experiments, although future experiments might play a role when compare it with the Gallium anomaly.

  9. Antineutrino monitoring for the Iranian heavy water reactor

    OpenAIRE

    Christensen, Eric; Huber, Patrick; Jaffke, Patrick; Shea, Thomas

    2014-01-01

    In this note we discuss the potential application of antineutrino monitoring to the Iranian heavy water reactor at Arak, the IR-40, as a non-proliferation measure. We demonstrate that an above ground detector positioned right outside the IR-40 reactor building could meet and in some cases significantly exceed the verification goals identified by IAEA for plutonium production or diversion from declared inventories. In addition to monitoring the reactor during operation, observing antineutrino ...

  10. Development of PROSPECT detectors for precision antineutrino studies

    OpenAIRE

    Norcini, Danielle; collaboration, for the PROSPECT

    2015-01-01

    PROSPECT, the Precision Reactor Oscillation and Spectrum Experiment, will use two segmented detectors positioned 7-20 m from the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory to measure the U-235 antineutrino spectrum and perform a search for short-baseline oscillations as a signature of eV-scale sterile neutrinos. PROSPECT has developed Li-6 loaded liquid scintillator detectors for efficient identification of reactor antineutrinos and has measured reactor and cosmogenic b...

  11. Antineutrino monitoring of burning mixed oxide plutonium fuels

    Science.gov (United States)

    Hayes, A. C.; Trellue, H. R.; Nieto, Michael Martin; Wilson, W. B.

    2012-02-01

    Background: Antineutrino monitoring of reactors is an enhanced nuclear safeguard that is being explored by several international groups. A key question is whether such a scheme could be used to verify the destruction of plutonium loaded in a reactor as mixed oxide (MOX) fuel.Purpose: To explore the effectiveness of antineutrino monitoring for the purposes of nuclear accountability and safeguarding of MOX plutonium, we examine the magnitude and temporal variation in the antineutrino signals expected for different loadings of MOX fuels.Methods: Reactor burn simulations are carried out for four different MOX fuel loadings and the antineutrino signals as a function of fuel burnup are computed and compared.Results: The antineutrino signals from reactor-grade and weapons-grade MOX are shown to be distinct from those from burning low enriched uranium, and this signal difference increases as the MOX plutonium fraction of the reactor core increases.Conclusion: Antineutrino monitoring could be used to verify the destruction of plutonium in reactors, although verifying the grade of the plutonium being burned is found to be more challenging.

  12. Experimental determination of the antineutrino spectrum of the fission products of 238U

    International Nuclear Information System (INIS)

    Haag, Nils-Holger

    2013-01-01

    Fission of 238 U contributes about 10 % to the antineutrino emission of a pressurized water reactor. In the present thesis, the beta spectrum of the fission products of 238 U was determined in an experiment at the neutron source FRM II. This beta spectrum was subsequently converted into an antineutrino spectrum. This first measurement of the antineutrino spectrum supports all current and future reactor antineutrino experiments.

  13. Experimental determination of the antineutrino spectrum of the fission products of {sup 238}U

    Energy Technology Data Exchange (ETDEWEB)

    Haag, Nils-Holger

    2013-10-09

    Fission of {sup 238}U contributes about 10 % to the antineutrino emission of a pressurized water reactor. In the present thesis, the beta spectrum of the fission products of {sup 238}U was determined in an experiment at the neutron source FRM II. This beta spectrum was subsequently converted into an antineutrino spectrum. This first measurement of the antineutrino spectrum supports all current and future reactor antineutrino experiments.

  14. Determining Reactor Fuel Type from Continuous Antineutrino Monitoring

    Science.gov (United States)

    Jaffke, Patrick; Huber, Patrick

    2017-09-01

    We investigate the ability of an antineutrino detector to determine the fuel type of a reactor. A hypothetical 5-ton antineutrino detector is placed 25 m from the core and measures the spectral shape and rate of antineutrinos emitted by fission fragments in the core for a number of 90-d periods. Our results indicate that four major fuel types can be differentiated from the variation of fission fractions over the irradiation time with a true positive probability of detection at approximately 95%. In addition, we demonstrate that antineutrinos can identify the burnup at which weapons-grade mixed-oxide (MOX) fuel would be reduced to reactor-grade MOX, on average, providing assurance that plutonium-disposition goals are met. We also investigate removal scenarios where plutonium is purposefully diverted from a mixture of MOX and low-enriched uranium fuel. Finally, we discuss how our analysis is impacted by a spectral distortion around 6 MeV observed in the antineutrino spectrum measured from commercial power reactors.

  15. Search for coherent muon pair production by neutrinos and antineutrinos

    International Nuclear Information System (INIS)

    Bergsma, F.; Dorenbosch, J.; Jonker, M.; Nieuwenhuis, C.; Allaby, J.V.; Amaldi, U.; Barbiellini, G.; Barone, L.; Capone, A.; Flegel, W.; Metcalf, M.; Panman, J.; Winter, K.; Aspiazu, J.; Buesser, F.W.; Daumann, H.; Gall, P.D.; Metz, E.; Niebergall, F.; Ranitzsch, K.H.; Staehelin, P.; Baroncelli, A.; Borgia, B.; Bosio, C.; Ferroni, F.; Longo, E.; Monacelli, P.; De Notaristefani, F.; Pistilli, P.; Santoni, C.; Tortora, L.; Valente, V.

    1983-01-01

    A search for coherent μ + μ - pair production has been made using the CHARM neutrino detector exposed to wide-band horn-focussed neutrino and antineutrino beams at the 400 GeV CERN SPS. Out of 3.3 x 10 6 neutrino and antineutrino induced CC events with energy greater than 10 GeV, we find two events which can be attributed to coherent production off the target nuclei (CaCO 3 ). This allows a limit to be set on the diagonal four-lepton coupling constant Gsub(d) < 1.5 Gsub(f) (90% CL). (orig.)

  16. The U238 antineutrino spectrum in the Double Chooz experiment

    Energy Technology Data Exchange (ETDEWEB)

    Haag, Nils; Oberauer, Lothar; Potzel, Walter; Schreckenbach, Klaus [Technische Universitaet, Muenchen (Germany); Lachenmaier, Tobias [Eberhard Karls Universitaet, Tuebingen (Germany)

    2011-07-01

    The DoubleChooz experiment aims at the determination of the unknown neutrino mixing parameter {Theta}{sub 13}. Two liquid scintillator detectors will measure an electron antineutrino disappearance at the Chooz site in the French ardennes. In order to improve the sensitivity, the antineutrino spectrum emitted by the Chooz reactor cores has to be determined with high accuracy. This talk focusses on the U238 spectrum, which is the only contributing spectrum, that was not measured until now. The final U238 beta spectrum is presented, and its implementation into the analysis framework is shown.

  17. Investigation of large LGB detectors for antineutrino detection

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, P. [Department of Physics, Naval Postgraduate School, Monterey, CA 93943 (United States); Bowden, N.S., E-mail: nbowden@llnl.gov [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)

    2011-12-21

    A detector material or configuration that can provide an unambiguous indication of neutron capture can substantially reduce random coincidence backgrounds in antineutrino detection and capture-gated neutron spectrometry applications. Here we investigate the performance of such a material, a composite of plastic scintillator and {sup 6}Li{sub 6}{sup nat}Gd({sup 10}BO{sub 3}){sub 3}:Ce (LGB) crystal shards of Almost-Equal-To 1 mm dimension and comprising 1% of the detector by mass. While it is found that the optical propagation properties of this material as currently fabricated are only marginally acceptable for antineutrino detection, its neutron capture identification ability is encouraging.

  18. Is there a high-y anomaly in antineutrino interactions

    International Nuclear Information System (INIS)

    Holder, M.; Knobloch, J.; May, J.; Paar, H.P.; Palazzi, P.; Schlatter, D.; Steinberger, J.; Suter, H.; Wahl, H.; Williams, E.G.H.; Eisele, F.; Geweniger, C.; Kleinknecht, K.; Spahn, G.; Wilutzki, H.; Dorth, W.; Dydak, F.; Hepp, V.; Tittel, K.; Wotschack, J.; Bloch, P.; Devaux, B.; Grimm, M.; Maillard, J.; Peyaud, B.; Rander, J.; Savoy-Navarro, A.; Turlay, R.; Navarria, F.L.

    1977-01-01

    We have analyzed data taken in the CERN narrow-band neutrino and antineutrino beams with regard to the ''high-y anomaly'' observed by previous experiments at Fermilab. At neutrino energies between 30 and 200 GeV, the anti ν and ν charged-current cross-section ratios and muon-inelasticity distributions disagree with the earlier results. In particular, there is no evidence for energy-dependent effects in the antineutrino data which constitute an important aspect of the alleged anomaly

  19. A study of quasi-elastic muon neutrino and antineutrino scattering in the NOMAD experiment

    Energy Technology Data Exchange (ETDEWEB)

    Lyubushkin, V.; Bunyatov, S.; Chukanov, A.; Klimov, O.; Kustov, D.; Nefedov, Yu.; Samoylov, O.; Tereshchenko, V. [JINR, Dubna (Russian Federation); Popov, B. [JINR, Dubna (Russian Federation); LPNHE, Univ. of Paris VI and VII, Paris (France); Kim, J.J.; Godley, A.; Ling, J.; Mishra, S.R.; Petti, R.; Seaton, M.; Wu, Q. [Univ. of South Carolina, Columbia, SC (United States); Camilleri, L.; Autiero, D.; Di Lella, L.; Couto e Silva, E. do; Ferrere, D.; Grant, A.; Kokkonen, J.; Linssen, L.; Placci, A.; Stiegler, U.; Tsesmelis, E.; Vidal-Sitjes, G.; Wilson, F.F. [CERN, Geneva (Switzerland); Levy, J.M.; Astier, P.; Banner, M.; Dumarchez, J.; Lachaud, C.; Letessier-Selvon, A.; Schahmaneche, K.; Touchard, A.M.; Vannucci, F. [LPNHE, Univ. of Paris VI and VII, Paris (France); Mezzetto, M.; Baldo-Ceolin, M.; Bobisut, F.; Collazuol, G.; Contalbrigo, M.; Gibin, D.; Guglielmi, A.; Lacaprara, S.; Laveder, M.; Rebuffi, L.; Sconza, A.; Zuccon, P. [Univ. of Padova (Italy); INFN, Padova (Italy); Naumov, D. [JINR, Dubna (Russian Federation); Univ. of Florence (Italy); INFN, Florence (Italy); Alekhin, S. [Inst. for High Energy Physics, Protvino, Moscow Region (Russian Federation); Baldisseri, A.; Besson, N.; Bouchez, J.; Gosset, J.; Hagner, C.; Mechain, X.; Meyer, J.P.; Stolarczyk, T.; Zaccone, H. [DAPNIA, Saclay (France); Bassompierre, G.; Gaillard, J.M.; Gouanere, M.; Mendiburu, J.P.; Nedelec, P.; Pessard, H.; Sillou, D. [LAPP, Annecy (France); Benslama, K.; Degaudenzi, H.; Joseph, C.; Juget, F.; Nguyen-Mau, C.; Sozzi, G.; Tareb-Reyes, M.; Tran, M.T.; Vacavant, L.; Vieira, J.M. [Univ. of Lausanne, Lausanne (Switzerland); Bird, I. [CERN, Geneva (Switzerland); Univ. of Lausanne (Switzerland); Blumenfeld, B.; Long, J. [Johns Hopkins Univ., Baltimore, MD (United States); Boyd, S.; Ellis, M.; Peak, L.S.; Ulrichs, J.; Varvell, K.E.; Yabsley, B.D. [Univ. of Sydney (Australia); Bueno, A. [Harvard Univ., Cambridge, MA (United States); ETH Zurich (Switzerland)] [and others

    2009-10-15

    We have studied the muon neutrino and antineutrino quasi-elastic (QEL) scattering reactions ({nu}{sub {mu}}n {yields}{mu}{sup -}p and anti {nu}{sub {mu}}p{yields}{mu}{sup +}n) using a set of experimental data collected by the NOMAD Collaboration. We have performed measurements of the cross-section of these processes on a nuclear target (mainly carbon) normalizing it to the total {nu}{sub {mu}}(anti {nu}{sub {mu}}) charged-current cross section. The results for the flux-averaged QEL cross sections in the (anti)neutrino energy interval 3-100 GeV are left angle {sigma}{sub qel} right angle {sub {nu}}{sub {mu}}=(0.92{+-}0.02(stat){+-}0.06(syst)) x 10{sup -38} cm{sup 2} and left angle {sigma}{sub qel} right angle {sub anti} {sub {nu}{sub {mu}}}{sub =}(0.81{+-}0.05(stat){+-}0.09(syst)) x 10{sup -38} cm{sup 2} for neutrino and antineutrino, respectively. The axial mass parameter M{sub A} was extracted from the measured quasi-elastic neutrino cross section. The corresponding result is M{sub A}=1.05{+-}0.02(stat){+-}0.06(syst) GeV. It is consistent with the axial mass values recalculated from the antineutrino cross section and extracted from the pure Q{sup 2} shape analysis of the high purity sample of {nu}{sub {mu}} quasi-elastic 2-track events, but has smaller systematic error and should be quoted as the main result of this work. Our measured M{sub A} is found to be in good agreement with the world average value obtained in previous deuterium filled bubble chamber experiments. The NOMAD measurement of M{sub A} is lower than those recently published by K2K and MiniBooNE Collaborations. However, within the large errors quoted by these experiments on M{sub A}, these results are compatible with the more precise NOMAD value. (orig.)

  20. Measuring Antineutrino Oscillations with the MINOS Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Justin John [Univ. of Oxford (United Kingdom)

    2008-09-01

    MINOS is a long baseline neutrino oscillation experiment. A manmade beam of predominantly muon neutrinos is detected both 1 km and 735 km from the production point by two functionally identical detectors. A comparison of the energy spectra measured by the two detectors shows the energy-dependent disappearance of muon neutrinos characteristic of oscillations and allows a measurement of the parameters governing the oscillations. This thesis presents work leading to measurements of disappearance in the 6% $\\bar{v}$μ background in that beam. A calibration is developed to correct for time-dependent changes in the responses of both detectors, reducing the corresponding uncertainty on hadronic energy measurements from 1.8% to 0.4% in the near detector and from 0.8% to 0.4% in the far detector. A method of selecting charged current $\\bar{v}$μ events is developed, with purities (efficiencies) of 96.5% (74.4%) at the near detector, and 98.8% (70.9%) at the far detector in the region below 10 GeV reconstructed antineutrino energy. A method of using the measured near detector neutrino energy spectrum to predict that expected at the far detector is discussed, and developed for use in the $\\bar{v}$μ analysis. Sources of systematic uncertainty contributing to the oscillation measurements are discussed. In the far detector, 32 charged current $\\bar{v}$μ events are observed below a reconstructed energy of 30 GeV, compared to an expectation of 47.8 for Δ$\\bar{m}$atm2 = Δ$\\bar{m}$atm2, sin2(2$\\bar{θ}$23) = sin2(2θ23). This deficit, in such a low-statistics sample, makes the result difficult to interpret in the context of an oscillation parameter measurement. Possible sources for the discrepancy are discussed, concluding that considerably more data are required for a definitive solution. Running MINOS with a dedicated $\\bar

  1. Prospects for improved understanding of isotopic reactor antineutrino fluxes

    Science.gov (United States)

    Gebre, Y.; Littlejohn, B. R.; Surukuchi, P. T.

    2018-01-01

    Predictions of antineutrino fluxes produced by fission isotopes in a nuclear reactor have recently received increased scrutiny due to observed differences in predicted and measured inverse beta decay (IBD) yields, referred to as the "reactor antineutrino flux anomaly." In this paper, global fits are applied to existing IBD yield measurements to produce constraints on antineutrino production by individual plutonium and uranium fission isotopes. We find that fits including measurements from highly U 235 -enriched cores and fits including Daya Bay's new fuel evolution result produce discrepant best-fit IBD yields for U 235 and Pu 239 . This discrepancy can be alleviated in a global analysis of all data sets through simultaneous fitting of Pu 239 , U 235 , and U 238 yields. The measured IBD yield of U 238 in this analysis is (7.02 ±1.65 )×10-43 cm2/fission , nearly two standard deviations below existing predictions. Future hypothetical IBD yield measurements by short-baseline reactor experiments are examined to determine their possible impact on the global understanding of isotopic IBD yields. It is found that future improved short-baseline IBD yield measurements at both high-enriched and low-enriched cores can significantly improve constraints for U 235 , U 238 , and Pu 239 , providing comparable or superior precision to existing conversion- and summation-based antineutrino flux predictions. Systematic and experimental requirements for these future measurements are also investigated.

  2. Monitoring of spent nuclear fuel with antineutrino detectors

    Science.gov (United States)

    Brdar, Vedran

    2017-09-01

    We put forward the possibility of employing antineutrino detectors in order to control the amounts of spent nuclear fuel in repositories or, alternatively, to precisely localize the underground sources of nuclear material. For instance, we discuss the applicability in determining a possible leakage of stored nuclear material which would aid in preventing environmental problems. The long-term storage facilities are also addressed.

  3. On neutrino and antineutrino scattering by electrons, and by partons

    International Nuclear Information System (INIS)

    Bell, J.S.; Dass, G.V.

    1975-09-01

    Assuming a non-derivative point interaction, and Born approximation, there are some simple relations between neutrino and antineutrino scattering on electrons or partons. They have been observed already, for some special cases, in the results of explicit calculations. Here they are obtained from simple general considerations. (author)

  4. Anti-neutrino imprint in solar neutrino flare

    Science.gov (United States)

    Fargion, D.

    2006-10-01

    A future neutrino detector at megaton mass might enlarge the neutrino telescope thresholds revealing cosmic supernova background and largest solar flares (SFs) neutrinos. Indeed the solar energetic (Ep>100 MeV) flare particles (protons, α), while scattering among themselves on solar corona atmosphere must produce prompt charged pions, whose chain decays are source of a solar (electron muon) neutrino 'flare' (at tens or hundreds MeV energy). These brief (minutes) neutrino 'bursts' at largest flare peak may overcome by three to five orders of magnitude the steady atmospheric neutrino noise on the Earth, possibly leading to their detection above detection thresholds (in a full mixed three flavour state). Moreover the birth of anti-neutrinos at a few tens of MeV very clearly flares above a null thermal 'hep' anti-neutrino solar background and also above a tiny supernova relic and atmospheric noise. The largest prompt solar anti-neutrino 'burst' may be well detected in future Super Kamikande (gadolinium implemented) anti-neutrino \\bar\

  5. Electron Neutrino and Antineutrino Appearance in the MINOS Detector

    Energy Technology Data Exchange (ETDEWEB)

    Schreckenberger, Adam Paul [Univ. of Minnesota, Minneapolis, MN (United States)

    2013-04-01

    The Main Injector Neutrino Oscillation Search (MINOS) is a long-baseline neutrino experiment that utilizes a particle beam and two steel-scintillator calorimeters designed to determine the parameters associated with muon neutrino disappearance. Analysis methods developed by the MINOS νe group have facilitated the placement of limits upon the mixing angle associated with νμ → νe oscillations. Since the polarity of the focusing horns can be switched, we can perform a similar analysis with an antineutrino-enriched beam to select electron antineutrino appearance candidates. Using 3.34e20 POT (protons on target) in the antineutrino mode, we exclude θ13 = 0 at the 80% C.L. A joint fit of the 3.34e20 POT antineutrino and 10.6e20 POT neutrino samples excluded θ13 = 0 at the 96% C.L. In addition, the combined data were used to produce exclusions regarding the CP-violating phase.

  6. Towards earth AntineutRino TomograpHy (EARTH)

    NARCIS (Netherlands)

    De Meijer, R. J.; Smit, F. D.; Brooks, F. D.; Fearick, R. W.; Wortche, H. J.; Mantovani, F.

    2006-01-01

    The programme Earth AntineutRino TomograpHy (EARTH) proposes to build ten underground facilities each hosting a telescope. Each telescope consists of many detector modules, to map the radiogenic heat sources deep in the interior of the Earth by utilising direction sensitive geoneutrino detection.

  7. Anti-neutrino flux in a research reactor for non-proliferation application

    Energy Technology Data Exchange (ETDEWEB)

    Khakshournia, Samad; Foroughi, Shokoufeh [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of). Atomic Energy Organization of Iran (AEOI)

    2017-11-15

    Owing to growing interest in the study of emitted antineutrinos from nuclear reactors to test the Atomic Energy Agency safeguards, antineutrino flux was studied in the Tehran Research Reactor (TRR) using ORIGEN code. According to our prediction, antineutrino rate was obtained 2.6 x 10{sup 17} (v{sub e}/sec) in the core No. 57F of the TRR. Calculations indicated that evolution of antineutrino flux was very slow with time and the performed refueling had not an observable effect on antineutrino flux curve for a 5 MW reactor with the conventional refueling program. It is seen that for non-proliferation applications the measurement of the contribution of {sup 239}Pu to the fission using an antineutrino detector is not viable in the TRR.

  8. Measuring of fissile isotopes partial antineutrino spectra in direct experiment at nuclear reactor

    OpenAIRE

    Sinev, V. V.

    2009-01-01

    The direct measuring method is considered to get nuclear reactor antineutrino spectrum. We suppose to isolate partial spectra of the fissile isotopes by using the method of antineutrino spectrum extraction from the inverse beta decay positron spectrum applied at Rovno experiment. This admits to increase the accuracy of partial antineutrino spectra forming the total nuclear reactor spectrum. It is important for the analysis of the reactor core fuel composition and could be applied for non-prol...

  9. A neutrino (antineutrino)-induced four lepton event

    International Nuclear Information System (INIS)

    Loveless, R.J.; Benada, R.; Camerini, U.; Duffy, M.; Fry, W.; McCabe, P.; Minette, D.; Ngai, M.; Reeder, D.D.; Cence, R.J.; Harris, F.A.; Jones, M.D.; Parker, S.I.; Peters, M.W.; Peterson, V.Z.; Wyatt, N.; Burnett, T.H.; Holmgren, D.; Lubatti, H.J.; Moriyasu, K.; Rudnicka, H.; Swider, G.M.; Wolin, E.; Yuldashev, B.S.

    1978-01-01

    Observation of a neutrino (antineutrino)-induced event with two electrons, one positron, one positively charged muon, a neutral K meson, and seven gammas in an experiment performed in the FNAL 15-ft bubble chamber with a 47% atomic mixture of neon in hydrogen is reported. Estimated experimental electron backgrounds are approximately 10 -4 per track. At present the authors have no plausible interpretation of this event. (Auth.)

  10. Net charge of quark jets in (anti)neutrino interactions

    International Nuclear Information System (INIS)

    Teper, M.

    1981-01-01

    We analyse recent measurements of the net charges of quark jets in neutrino and antineutrino interactions. The data indicates that (i) the two quarks in the nucleon fragmentation region prefer to behave as a diquark rather than as a pair of independent quarks, and (ii) the struck quark does not appear to suffer any soft charge exchange of the kind that occurs when a valence quark inside a nucleon is slowed to x approx. O. (orig.)

  11. Antineutrino Neutral Current Interactions in MiniBooNE

    Energy Technology Data Exchange (ETDEWEB)

    Dharmapalan, Ranjan [Univ. of Alabama, Tuscaloosa, AL (United States)

    2012-01-01

    This dissertation reports the antineutrino-nucleus neutral current elastic scattering cross section on CH2 measured by the MiniBooNE experiment located in Batavia, IL. The data set consists of 60,605 events passing the selection cuts corresponding to 10.1×1020 POT, which represents the world’s largest sample of antineutrino neutral current elastic scattering events. The final sample is more than one order of magnitude lager that the previous antineutrino NCE scattering cross section measurement reported by the BNL E734 experiment. The measurement presented in this dissertation also spans a wider range in Q2, including the low-Q2 regime where the cross section rollover is clearly visible. A X2-based minimization was performed to determine the best value of the axial mass, MA and the Pauli blocking scaling function, that matches the antineutrino NCE scattering data. However, the best fit values of MA=1.29 GeV and K=1.026 still give a relatively poor X2, which suggests that the underlying nuclear model (based largely on the relativistic Fermi gas model) may not be an accurate representation for this particular interaction. Additionally, we present a measurement of the antineutrino/neutrino-nucleus NCE scattering cross section ratio. The neutrino mode NCE sample used in this study, corresponding to 6.4 × 1020 POT, is also the world’s largest sample (also by an order of magnitude). We have demonstrated that the ratio measurement is robust, as most of the correlated errors cancel, as expected. Furthermore, this ratio also proves to be rather insensitive to variations in the axial mass and the Pauli blocking parameter. This is the first time that this ratio has been experimentally reported. We believe this measurement will aid the theoretical physics community to test various model predictions of neutrino-nucleon/nucleus interactions.

  12. Use of Antineutrino Detectors for Nuclear Reactor Safeguards Effectiveness Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, A; Lambert, H E; Elayat, H A; O' Connell, W J; Rexroth, P; Baldwin, G; Bowden, N; Huelskamp, R

    2006-06-05

    As described in an earlier article [1], important information regarding reactor power and the amount and type of fissile material in reactor cores can be determined by measuring the antineutrino rate and energy spectrum, using a cubic meter scale antineutrino detector at tens of meters standoff from the core. Current International Atomic Energy Agency (IAEA) safeguards techniques do not provide such real-time quantitative information regarding core power levels and isotopic composition. The possible benefits of this approach are several and have been discussed in the earlier article. One key advantage is that the method gives the inspecting agency completely independent access to real-time information on the operational status and fissile content of the core. Furthermore, the unattended and non-intrusive nature of the technology may reduce the monitoring burden on the plant operator, even though more information is being provided than is available within the current IAEA safeguards regime. Here we present a detailed analytical framework for measuring the impact that such a detector might have on IAEA safeguards, if implemented. To perform the analysis, we will use initial data from our operating detector and a standard analysis technique for safeguards regimes, developed at Lawrence Livermore National Laboratory. Because characterization of the prototype detector is still underway, and because improvements in the prototype could have important impact on safeguards performance, the results presented here should be understood to be preliminary, and not reflective of the ultimate performance of the system. The structure of this paper is as follows. Reactor safeguards and the relevant properties of antineutrino detectors are briefly reviewed. A set of hypothetical diversion scenarios are then described, and one of these is analyzed using the Lawrence Livermore National Laboratory Integrated Safeguards System Analysis Tool (LISSAT) The probability of successful

  13. Leakage Tests of the Stainless Steel Vessels of the Antineutrino Detectors in the Daya Bay Reactor Neutrino Experiment

    OpenAIRE

    Chen, Xiaohui; Luo, Xiaolan; Heng, Yuekun; Wang, Lingshu; Tang, Xiao; Ma, Xiaoyan; Zhuang, Honglin; Band, Henry; Cherwinka, Jeff; Xiao, Qiang; Heeger, Karsten M.

    2012-01-01

    The antineutrino detectors in the Daya Bay reactor neutrino experiment are liquid scintillator detectors designed to detect low energy particles from antineutrino interactions with high efficiency and low backgrounds. Since the antineutrino detector will be installed in a water Cherenkov cosmic ray veto detector and will run for 3 to 5 years, ensuring water tightness is critical to the successful operation of the antineutrino detectors. We choose a special method to seal the detector. Three l...

  14. Reactors as a source of antineutrinos: the effect of fuel loading and burnup for mixed oxide fuels

    OpenAIRE

    Bernstein, Adam; Bowden, Nathaniel; Erickson, Anna

    2016-01-01

    In a conventional light water reactor loaded with a range of uranium and plutonium-based fuel mixtures, the variation in antineutrino production over the cycle reflects both the initial core fissile inventory and its evolution. Under the assumption of constant thermal power, we calculate the rate at which antineutrinos are emitted from variously fueled cores, and the evolution of that rate as measured by a representative ton-scale antineutrino detector. We find that antineutrino flux decrease...

  15. Antineutrino Oscillations and a Search for Non-standard Interactions with the MINOS

    Energy Technology Data Exchange (ETDEWEB)

    Isvan, Zeynep [Univ. of Pittsburgh, PA (United States)

    2012-01-01

    MINOS searches for neutrino oscillations using the disappearance of muon neutrinos from the NuMI beam at Fermilab between two detectors. The Near Detector, located near the source, measures the beam composition before flavor change occurs. The energy spectrum is measured again at the Far Detector after neutrinos travel a distance. The mixing angle and mass splitting between the second and third mass states are extracted from the energy dependent difference between the spectra at the two detectors. NuMI is able to produce an antineutrino-enhanced beam as well as a neutrino-enhanced beam. Collecting data in antineutrino-mode allows the direct measurement of antineutrino oscillation parameters. From the analysis of the antineutrino mode data we measure $|\\Delta\\bar{m}^{2}_{\\text{atm}}| = 2.62^{+0.31}_{-0.28}\\times10^{-3}\\text{eV}^{2}$ and $\\sin^{2}(2\\bar{\\theta})_{23} = 0.95^{+0.10}_{-0.11}$, which is the most precise measurement of antineutrino oscillation parameters to date. A difference between neutrino and antineutrino oscillation parameters may indicate new physics involving interactions that are not part of the Standard Model, called non-standard interactions, that alter the apparent disappearance probability. Collecting data in neutrino and antineutrino mode independently allows a direct search for non-standard interactions. In this dissertation non-standard interactions are constrained by a combined analysis of neutrino and antineutrino datasets and no evidence of such interactions is found.

  16. Search for the Neutrino Magnetic Moment in the Non-Equilibrium Reactor Antineutrino Energy Spectrum

    OpenAIRE

    Kopeikin, V. I.; Mikaelyan, L. A.; Sinev, V. V.

    1999-01-01

    We study the time evolution of the typical nuclear reactor antineutrino energy spectrum during reactor ON period and the decay of the residual antineutrino spectrum after reactor is stopped. We find that relevant variations of the soft recoil electron spectra produced via weak and magnetic ${\\widetilde {\

  17. The upper limit of the solar antineutrino flux according to the LSD array data

    International Nuclear Information System (INIS)

    Al'etta, M.; Antonioli, P.; Badino, D.

    1997-01-01

    The analysis of the experimental data obtained at the LSD liquid scintillation detector is carried out with the aim of searching the possible flux of electron antineutrinos from Sun. The most strong at present upper limit for the electron antineutrino flux of solar origin is determined: ≤ 1.0 x 10 5 cm -2 x s -1 (the reliability level of 90%)

  18. Dilepton and trilepton production by antineutrinos and neutrinos in neon

    Science.gov (United States)

    Gerbier, G.; Bertrand, D.; Guy, J.; Marage, P.; Aderholz, M.; Armenise, N.; Bartley, J. H.; Baton, J. P.; Brisson, V.; Belusevic, R.; Brou, D.; Bullock, F. W.; Calicchio, M.; Clayton, E. F.; Coghen, T.; Cooper-Sarkar, A. M.; Erriquez, O.; Fitch, P. J.; Hulth, P. O.; Jones, G. T.; Kasper, P.; Klein, H.; Kochowski, C.; Lagraa, M.; Leighton-Davis, S.; Middleton, R.; Miller, D. B.; Mobayyen, M. M.; Morrison, D. R. O.; Neveu, M.; Nuzzo, S.; O'Neale, S.; Parker, M. A.; Petiau, P.; Sacton, J.; Sansum, R. A.; Schmitz, N.; Simopoulou, E.; Talebzadeh, M.; Varvell, K.; Vallee, C.; Vayaki, A.; Venus, W.; Wachsmuth, H.; Wells, J.; Wittek, W.; Zevgolatakos, E.

    1985-03-01

    A sample of over 25,000 fully measured neutrino and antineutrino charged current interactions in BEBC includes 192 dilepton candidates. The prompt signal after subtraction of background is 41 ±7µ+ e -, 35±7µ+µ- events frombar v interactions, and 32±7µ-µ+ events from ν interactions. There are 2 trileptons, µ-µ- e + and µ-µ-µ+. Results are compared with other experimental data and with the standard model. Limits to prompt like sign µ+ e +, µ+µ+ and µ-µ- signals are given and compared with other experiments and with theoretical calculations.

  19. Search for differences in oscillation parameters for atmospheric neutrinos and antineutrinos at Super-Kamiokande.

    Science.gov (United States)

    Abe, K; Hayato, Y; Iida, T; Ikeda, M; Iyogi, K; Kameda, J; Koshio, Y; Kozuma, Y; Miura, M; Moriyama, S; Nakahata, M; Nakayama, S; Obayashi, Y; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Takenaga, Y; Takeuchi, Y; Ueno, K; Ueshima, K; Watanabe, H; Yamada, S; Yokozawa, T; Ishihara, C; Kaji, H; Lee, K P; Kajita, T; Kaneyuki, K; McLachlan, T; Okumura, K; Shimizu, Y; Tanimoto, N; Martens, K; Vagins, M R; Labarga, L; Magro, L M; Dufour, F; Kearns, E; Litos, M; Raaf, J L; Stone, J L; Sulak, L R; Goldhaber, M; Bays, K; Kropp, W R; Mine, S; Regis, C; Smy, M B; Sobel, H W; Ganezer, K S; Hill, J; Keig, W E; Jang, J S; Kim, J Y; Lim, I T; Albert, J B; Scholberg, K; Walter, C W; Wendell, R; Wongjirad, T M; Tasaka, S; Learned, J G; Matsuno, S; Hasegawa, T; Ishida, T; Ishii, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Nishikawa, K; Nishino, H; Oyama, Y; Sakashita, K; Sekiguchi, T; Tsukamoto, T; Suzuki, A T; Minamino, A; Nakaya, T; Fukuda, Y; Itow, Y; Mitsuka, G; Tanaka, T; Jung, C K; Taylor, I; Yanagisawa, C; Ishino, H; Kibayashi, A; Mino, S; Mori, T; Sakuda, M; Toyota, H; Kuno, Y; Kim, S B; Yang, B S; Ishizuka, T; Okazawa, H; Choi, Y; Nishijima, K; Koshiba, M; Yokoyama, M; Totsuka, Y; Chen, S; Heng, Y; Yang, Z; Zhang, H; Kielczewska, D; Mijakowski, P; Connolly, K; Dziomba, M; Wilkes, R J

    2011-12-09

    We present a search for differences in the oscillations of antineutrinos and neutrinos in the Super-Kamiokande-I, -II, and -III atmospheric neutrino sample. Under a two-flavor disappearance model with separate mixing parameters between neutrinos and antineutrinos, we find no evidence for a difference in oscillation parameters. Best-fit antineutrino mixing is found to be at (Δm2,sin2 2θ)=(2.0×10(-3)  eV2, 1.0) and is consistent with the overall Super-K measurement.

  20. A study of inclusive antineutrino interactions in propane

    International Nuclear Information System (INIS)

    Ramzan, F.A.

    1979-02-01

    Some results obtained using the heavy liquid bubble chamber Gargamelle situated at the CERN Proton Synchrotron neutrino beam facility are presented. The deep inelastic scattering of antineutrinos is analysed and interpreted in the theoretical framework of Bjorken scaling and the Quark Parton model of the nucleon. This model predicts that scaling should occur in regions of high four momentum squared. The effect of not being in that region is investigated. In particular the data suggest that in the region of low four momentum transfer the results can still be interpreted in the scaling framework. A model is presented which enables extraction of the neutron to proton cross section, and the result is interpreted within the quark model. (author)

  1. Analysis of the Daya Bay Reactor Antineutrino Flux Changes with Fuel Burnup

    Science.gov (United States)

    Hayes, A. C.; Jungman, Gerard; McCutchan, E. A.; Sonzogni, A. A.; Garvey, G. T.; Wang, X. B.

    2018-01-01

    We investigate the recent Daya Bay results on the changes in the antineutrino flux and spectrum with the burnup of the reactor fuel. We find that the discrepancy between current model predictions and the Daya Bay results can be traced to the original measured U 235 /Pu 239 ratio of the fission β spectra that were used as a base for the expected antineutrino fluxes. An analysis of the antineutrino spectra that is based on a summation over all fission fragment β decays, using nuclear database input, explains all of the features seen in the Daya Bay evolution data. However, this summation method still allows for an anomaly. We conclude that there is currently not enough information to use the antineutrino flux changes to rule out the possible existence of sterile neutrinos.

  2. Precision Search for Muon Antineutrino Disappearance Oscillations Using a Dual Baseline Technique

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Gary Li [Columbia Univ., New York, NY (United States)

    2013-01-01

    A search for short baseline muon antineutrino disappearance with the SciBooNE and MiniBooNE experiments at Fermi National Accelerator Laboratory in Batavia, Illinois is presented. Short baseline muon antineutrino disappearance measurements help constrain sterile neutrino models. The two detectors observe muon antineutrinos from the same beam, therefore the combined analysis of their data sets serves to partially constrain some of the flux and cross section uncertainties. A likelihood ratio method was used to set a 90% confidence level upper limit on muon antineutrino disappearance that dramatically improves upon prior sterile neutrino oscillation limits in the Δm2=0.1-100 eV2 region.

  3. Opportunities for applied measurements using the PROSPECT antineutrino detector: reactor physics and safeguards

    Science.gov (United States)

    Bowden, Nathaniel; Prospect Collaboration

    2015-10-01

    Disagreement of reactor antineutrino spectrum and flux measurements with updated predictions indicates that we have much to learn about the complicated processes underlying antineutrino production in reactors, as well as hinting at new physics. A number of new efforts seek to address these questions, including the PROSPECT experiment planned at the HFIR research reactor. In addition to greatly advancing our understanding of reactor antineutrino emissions, PROSPECT can support a rich applied physics program. The detection technology developed for PROSPECT will enable precision antineutrino spectrum measurements close to essentially any reactor type. Here we describe how such measurements provide opportunities to probe fissile isotope and fission daughter distributions, and their potential use for reactor physics and safeguards applications. LLNL-ABS-673983. Prepared by LLNL under Contract DE-AC52-07NA27344.

  4. Measurement of charm production in antineutrino charged-current interactions

    CERN Document Server

    Onengüt, G; De Jong, M; Konijn, J; Melzer, O; Oldeman, R G C; Pesen, E; Van der Poel, C A F J; Visschers, J L; Güler, M; Köse, U; Serin-Zeyrek, M; Kama, S; Sever, R; Tolun, P; Zeyrek, M T; Catanesi, M G; De Serio, M; Ieva, M; Muciaccia, M T; Radicioni, E; Simone, S; Bülte, A; Winter, Klaus; Van de Vyver, B; Vilain, P; Wilquet, G; Saitta, B; Di Capua, E; Ogawa, S; Shibuya, H; Artamonov, A V; Brunner, J; Chizhov, M; Cussans, D G; Doucet, M; Fabre, Jean-Paul; Hristova, I R; Kawamura, T; Kolev, D; Litmaath, M; Meinhard, H; Panman, J; Papadopoulos, I M; Ricciardi, S; Rozanov, A; Saltzberg, D; Tsenov, R V; Uiterwijk, J W E; Zucchelli, P; Goldberg, J; Chikawa, M; Arik, E; Song, J S; Yoon, C S; Kodama, K; Ushida, N; Aoki, S; Hara, T; Delbar, T; Favart, D; Grégoire, G; Kalinin, S; Makhlyoueva, I V; Gorbunov, P; Khovanskii, V D; Shamanov, V V; Tsukerman, I; Bruski, N; Frekers, D; Rondeshagen, D; Wolff, T; Hoshino, K; Kawada, J; Komatsu, M; Miyanishi, M; Nakamura, M; Nakano, T; Narita, K; Niu, K; Niwa, K; Nonaka, N; Sato, O; Toshito, T; Buontempo, S; Cocco, A G; D'Ambrosio, N; De Lellis, G; De Rosa, G; Di Capua, F; Ereditato, A; Fiorillo, G; Marotta, A; Messina, M; Migliozzi, P; Pistillo, C; Santorelli, R; Scotto-Lavina, L; Strolin, P; Tioukov, V; Nakamura, K; Okusawa, T; Dore, U; FLoverre, P; Ludovici, L; Maslennikov, A L; Righini, P; Rosa, G; Santacesaria, R; Satta, A; Spada, F R; Barbuto, E; Bozza, C; Grella, G; Romano, G; Sirignano, C; Sorrentino, S; Sato, Y; Tezuka, I

    2004-01-01

    During the years 1994-97, the emulsion target of the CHORUS detector was exposed to the wideband neutrino beam of the CERN SPS collecting about 10^6 neutrino interactions. A measurement of nubar_mu-induced charm production is performed by usingthe presence of a 5% nubarmu component in the nu_mu beam. The measurement takes advantage of the capability to observe the decay topology in the emulsion. The analysis is based on a sample of charged-current interactions with at least one identified muon. About 100 000 vere located in the emulsion target and fully reconstructed. By requiring a positive muon charge as determined by the CHORUS spectrometer, 32-nubar_mu induced charm events were observed with an estimated background of 3.2 events. At an average antineutrino energy in the neutrino beam of 18GeV, the charm production rate induced by anitneutrinos is measured to be sigma(nubar_muN -> mu+cbarX)/sigma(nubar_muN -> mu+X) = (5.0^+1.4_-0.9(stat) +- 0.7(syst))%. The ratio between neutral and charged charm productio...

  5. Gadolinium-loaded gel scintillators for neutron and antineutrino detection

    Energy Technology Data Exchange (ETDEWEB)

    Riddle, Catherine Lynn; Akers, Douglas William; Demmer, Ricky Lynn; Paviet, Patricia Denise; Drigert, Mark William

    2016-11-29

    A gadolinium (Gd) loaded scintillation gel (Gd-ScintGel) compound allows for neutron and gamma-ray detection. The unique gel scintillator encompasses some of the best features of both liquid and solid scintillators, yet without many of the disadvantages associated therewith. Preferably, the gel scintillator is a water soluble Gd-DTPA compound and water soluble fluorophores such as: CdSe/ZnS (or ZnS) quantum dot (Q-dot) nanoparticles, coumarin derivatives 7-hydroxy-4-methylcoumarin, 7-hydroxy-4-methylcoumarin-3-acetic acid, 7-hydroxycoumarin-3-carboxylic acid, and Alexa Fluor 350 as well as a carbostyril compound, carbostyril 124 in a stable water-based gel, such as methylcellulose or polyacrylamide polymers. The Gd-loaded ScintGel allows for a homogenious distribution of the Gd-DTPA and the fluorophores, and yields clean fluorescent emission peaks. A moderator, such as deuterium or a water-based clear polymer, can be incorporated in the Gd-ScintGel. The gel scintillators can be used in compact detectors, including neutron and antineutrino detectors.

  6. Reactors as a Source of Antineutrinos: Effects of Fuel Loading and Burnup for Mixed-Oxide Fuels

    Science.gov (United States)

    Bernstein, Adam; Bowden, Nathaniel S.; Erickson, Anna S.

    2018-01-01

    In a conventional light-water reactor loaded with a range of uranium and plutonium-based fuel mixtures, the variation in antineutrino production over the cycle reflects both the initial core fissile inventory and its evolution. Under an assumption of constant thermal power, we calculate the rate at which antineutrinos are emitted from variously fueled cores, and the evolution of that rate as measured by a representative ton-scale antineutrino detector. We find that antineutrino flux decreases with burnup for low-enriched uranium cores, increases for full mixed-oxide (MOX) cores, and does not appreciably change for cores with a MOX fraction of approximately 75%. Accounting for uncertainties in the fission yields in the emitted antineutrino spectra and the detector response function, we show that the difference in corewide MOX fractions at least as small as 8% can be distinguished using a hypothesis test. The test compares the evolution of the antineutrino rate relative to an initial value over part or all of the cycle. The use of relative rates reduces the sensitivity of the test to an independent thermal power measurement, making the result more robust against possible countermeasures. This rate-only approach also offers the potential advantage of reducing the cost and complexity of the antineutrino detectors used to verify the diversion, compared to methods that depend on the use of the antineutrino spectrum. A possible application is the verification of the disposition of surplus plutonium in nuclear reactors.

  7. An assessment of anti-neutrino mass determination via electrostatic measurements of tritium beta-decay

    International Nuclear Information System (INIS)

    Le Bas, P.A.

    1984-01-01

    Data on the mass of the anti-neutrino determined via electrostatic measurements of tritium beta-decay are assessed. Relativistic calculations concerning the finite mass of the electron anti-neutrino and the recoil of the nucleus, are given for the theoretical end-point spectrum of tritium beta-decay. The specifications are given for an electrostatic Spherical Retarding Beta-Spectrometer, and an electrostatic Cylindrical Mirror Analyser, both used in the tritium beta-decay experiment. The electrostatic measurements lead to a value of less than 50 ev (90% C.L.) for the electron anti-neutrino mass. These results are discussed in terms of the resolution of the electrostatic equipment and the Monte Carlo simulations of the data collection. (UK)

  8. Search for Lorentz invariance and CPT violation with muon antineutrinos in the MINOS Near Detector

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, P. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); et al.

    2012-02-01

    We have searched for sidereal variations in the rate of antineutrino interactions in the MINOS Near Detector. Using antineutrinos produced by the NuMI beam, we find no statistically significant sidereal modulation in the rate. When this result is placed in the context of the Standard Model Extension theory we are able to place upper limits on the coefficients defining the theory. These limits are used in combination with the results from an earlier analysis of MINOS neutrino data to further constrain the coefficients.

  9. Two particle–hole excitations in charged current quasielastic antineutrino-nucleus scattering

    International Nuclear Information System (INIS)

    Nieves, J.; Ruiz Simo, I.; Vicente Vacas, M.J.

    2013-01-01

    We evaluate the quasielastic and multinucleon contributions to the antineutrino-nucleus scattering cross section and compare our results with the recent MiniBooNE data. We use a local Fermi gas model that includes RPA correlations and gets the multinucleon part from a systematic many body expansion of the W boson selfenergy in the nuclear medium. The same model had been quite successful for the neutrino cross section and contains no new parameters. We have also analyzed the relevance of 2p2h events for the antineutrino energy reconstruction

  10. First test of Lorentz violation with a reactor-based antineutrino experiment

    International Nuclear Information System (INIS)

    Abe, Y.; Ishitsuka, M.; Konno, T.; Kuze, M.; Aberle, C.; Buck, C.; Hartmann, F.X.; Haser, J.; Kaether, F.; Lindner, M.; Reinhold, B.; Schwetz, T.; Wagner, S.; Watanabe, H.; Anjos, J.C. dos; Gama, R.; Lima, H.P.-Jr.; Pepe, I.M.; Bergevin, M.; Felde, J.; Maesano, C.N.; Bernstein, A.; Bowden, N.S.; Dazeley, S.; Erickson, A.; Keefer, G.; Bezerra, T.J.C.; Furuta, H.; Suekane, F.; Bezrukhov, L.; Lubsandorzhiev, B.K.; Yanovitch, E.; Blucher, E.; Conover, E.; Crum, K.; Strait, M.; Worcester, M.; Busenitz, J.; Goon, J.TM.; Habib, S.; Ostrovskiy, I.; Reichenbacher, J.; Stancu, I.; Sun, Y.; Cabrera, A.; Franco, D.; Kryn, D.; Obolensky, M.; Roncin, R.; Tonazzo, A.; Caden, E.; Damon, E.; Lane, C.E.; Maricic, J.; Miletic, T.; Milincic, R.; Perasso, S.; Smith, E.; Camilleri, L.; Carr, R.; Franke, A.J.; Shaevitz, M.H.; Toups, M.; Cerrada, M.; Crespo-Anadon, J.I.; Gil-Botella, I.; Lopez-Castano, J.M.; Novella, P.; Palomares, C.; Santorelli, R.; Chang, P.J.; Horton-Smith, G.A.; McKee, D.; Shrestha, D.; Chimenti, P.; Classen, T.; Collin, A.P.; Cucoanes, A.; Durand, V.; Fechner, M.; Fischer, V.; Hayakawa, T.; Lasserre, T.; Letourneau, A.; Lhuillier, D.; Mention, G.; Mueller, Th.A.; Perrin, P.; Sida, J.L.; Sinev, V.; Veyssiere, C.

    2012-01-01

    We present a search for Lorentz violation with 8249 candidate electron antineutrino events taken by the Double Chooz experiment in 227.9 live days of running. This analysis, featuring a search for a sidereal time dependence of the events, is the first test of Lorentz invariance using a reactor-based antineutrino source. No sidereal variation is present in the data and the disappearance results are consistent with sidereal time independent oscillations. Under the Standard-Model Extension, we set the first limits on 14 Lorentz violating coefficients associated with transitions between electron and tau flavor, and set two competitive limits associated with transitions between electron and muon flavor. (authors)

  11. Monte Carlo Simulation of a Segmented Detector for Low-Energy Electron Antineutrinos

    Science.gov (United States)

    Qomi, H. Akhtari; Safari, M. J.; Davani, F. Abbasi

    2017-11-01

    Detection of low-energy electron antineutrinos is of importance for several purposes, such as ex-vessel reactor monitoring, neutrino oscillation studies, etc. The inverse beta decay (IBD) is the interaction that is responsible for detection mechanism in (organic) plastic scintillation detectors. Here, a detailed study will be presented dealing with the radiation and optical transport simulation of a typical segmented antineutrino detector withMonte Carlo method using MCNPX and FLUKA codes. This study shows different aspects of the detector, benefiting from inherent capabilities of the Monte Carlo simulation codes.

  12. Total Absorption Spectroscopy of Fission Fragments Relevant for Reactor Antineutrino Spectra and Decay Heat Calculations

    Directory of Open Access Journals (Sweden)

    Porta A.

    2016-01-01

    Full Text Available Beta decay of fission products is at the origin of decay heat and antineutrino emission in nuclear reactors. Decay heat represents about 7% of the reactor power during operation and strongly impacts reactor safety. Reactor antineutrino detection is used in several fundamental neutrino physics experiments and it can also be used for reactor monitoring and non-proliferation purposes. 92,93Rb are two fission products of importance in reactor antineutrino spectra and decay heat, but their β-decay properties are not well known. New measurements of 92,93Rb β-decay properties have been performed at the IGISOL facility (Jyväskylä, Finland using Total Absorption Spectroscopy (TAS. TAS is complementary to techniques based on Germanium detectors. It implies the use of a calorimeter to measure the total gamma intensity de-exciting each level in the daughter nucleus providing a direct measurement of the beta feeding. In these proceedings we present preliminary results for 93Rb, our measured beta feedings for 92Rb and we show the impact of these results on reactor antineutrino spectra and decay heat calculations.

  13. Sterile neutrinos or flux uncertainties? — Status of the reactor anti-neutrino anomaly

    Science.gov (United States)

    Dentler, Mona; Hernández-Cabezudo, Álvaro; Kopp, Joachim; Maltoni, Michele; Schwetz, Thomas

    2017-11-01

    The ˜ 3 σ discrepancy between the predicted and observed reactor anti-neutrino flux, known as the reactor anti-neutrino anomaly, continues to intrigue. The recent discovery of an unexpected bump in the reactor anti-neutrino spectrum, as well as indications that the flux deficit is different for different fission isotopes seems to disfavour the explanation of the anomaly in terms of sterile neutrino oscillations. We critically review this conclusion in view of all available data on electron (anti)neutrino disappearance. We find that the sterile neutrino hypothesis cannot be rejected based on global data and is only mildly disfavored compared to an individual rescaling of neutrino fluxes from different fission isotopes. The main reason for this is the presence of spectral features in recent data from the NEOS and DANSS experiments. If state-of-the-art predictions for reactor fluxes are taken at face value, sterile neutrino oscillations allow a consistent description of global data with a significance close to 3 σ relative to the no-oscillation case. Even if reactor fluxes and spectra are left free in the fit, a 2 σ hint in favour of sterile neutrinos remains, with allowed parameter regions consistent with an explanation of the anomaly in terms of oscillations.

  14. Neutrino and antineutrino inclusive charged-current cross section measurement with the MINOS near detector

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Debdatta [Univ. of Pittsburgh, PA (United States)

    2009-01-01

    This thesis presents the measurement of energy dependence of the neutrino-nucleon inclusive charged current cross section on an isoscalar target in the range 3-50 GeV for neutrinos and 5-50 GeV energy range for antineutrinos. The data set was collected with the MINOS Near Detector using the wide band NuMI beam at Fermilab. The size of the charged current sample is 1.94 x 106 neutrino events and 1.60 x 105 antineutrino events. The flux has been extracted using a low hadronic energy sub-sample of the charged current events. The energy dependence of the cross section is obtained by dividing the charged current sample with the extracted flux. The neutrino and antineutrino cross section exhibits a linear dependence on energy at high energy but shows deviations from linear behavior at low energy. We also present a measurement of the ratio of antineutrino to neutrino inclusive cross section.

  15. New Decay Data Sub-library for Calculation of Nuclear Reactors Antineutrino Spectra

    Science.gov (United States)

    Sonzogni, Alejandro; McCutchan, Elizabeth; Johnson, Timothy

    2015-10-01

    The ENDF/B-VII.1 decay data sub-library contains up-to-date decay properties for all known nuclides and can be used in a wide variety of applications such as decay heat, delayed nu-bar and astrophysics. We have recently completed an upgrade to the ENDF/B-VII.1 decay data sub-library in order to better calculate antineutrino spectra from fission of actinide nuclides. This sub-library has been used to identify the main contributors to the antineutrino spectra as well as to derive a systematic behavior of the energy integrated spectra similar to that of the beta-delayed neutron multiplicities. The main improvements have been the use of the TAGS data from Algora et al and Greenwood et al, as well as some of the single beta spectrum data from Rudstam et al to obtain beta minus level feedings. Additionally, we have calculated the antineutrino spectra for neutron energies higher than thermal, needed for highly-enriched uranium cores, such as the HFIR in ORNL that will be used in the PROSPECT experiment. These calculations are relevant since the high precision beta spectra which are used in many antineutrino calculations were measured at thermal energies. The impact of the fission yield data on these calculations will be discussed. This work was sponsored by the Office of Nuclear Physics, Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-98CH10886.

  16. Modelling of the anti-neutrino production and spectra from a Magnox reactor

    Science.gov (United States)

    Mills, Robert W.; Mountford, David J.; Coleman, Jonathon P.; Metelko, Carl; Murdoch, Matthew; Schnellbach, Yan-Jie

    2018-01-01

    The anti-neutrino source properties of a fission reactor are governed by the production and beta decay of the radionuclides present and the summation of their individual anti-neutrino spectra. The fission product radionuclide production changes during reactor operation and different fissioning species give rise to different product distributions. It is thus possible to determine some details of reactor operation, such as power, from the anti-neutrino emission to confirm safeguards records. Also according to some published calculations, it may be feasible to observe different anti-neutrino spectra depending on the fissile contents of the reactor fuel and thus determine the reactor's fissile material inventory during operation which could considerable improve safeguards. In mid-2014 the University of Liverpool deployed a prototype anti-neutrino detector at the Wylfa R1 station in Anglesey, United Kingdom based upon plastic scintillator technology developed for the T2K project. The deployment was used to develop the detector electronics and software until the reactor was finally shutdown in December 2015. To support the development of this detector technology for reactor monitoring and to understand its capabilities, the National Nuclear Laboratory modelled this graphite moderated and natural uranium fuelled reactor with existing codes used to support Magnox reactor operations and waste management. The 3D multi-physics code PANTHER was used to determine the individual powers of each fuel element (8×6152) during the year and a half period of monitoring based upon reactor records. The WIMS/TRAIL/FISPIN code route was then used to determine the radionuclide inventory of each nuclide on a daily basis in each element. These nuclide inventories were then used with the BTSPEC code to determine the anti-neutrino spectra and source strength using JEFF-3.1.1 data. Finally the anti-neutrino source from the reactor for each day during the year and a half of monitored reactor

  17. Modelling of the anti-neutrino production and spectra from a Magnox reactor

    Directory of Open Access Journals (Sweden)

    Mills Robert W

    2018-01-01

    Full Text Available The anti-neutrino source properties of a fission reactor are governed by the production and beta decay of the radionuclides present and the summation of their individual anti-neutrino spectra. The fission product radionuclide production changes during reactor operation and different fissioning species give rise to different product distributions. It is thus possible to determine some details of reactor operation, such as power, from the anti-neutrino emission to confirm safeguards records. Also according to some published calculations, it may be feasible to observe different anti-neutrino spectra depending on the fissile contents of the reactor fuel and thus determine the reactor's fissile material inventory during operation which could considerable improve safeguards. In mid-2014 the University of Liverpool deployed a prototype anti-neutrino detector at the Wylfa R1 station in Anglesey, United Kingdom based upon plastic scintillator technology developed for the T2K project. The deployment was used to develop the detector electronics and software until the reactor was finally shutdown in December 2015. To support the development of this detector technology for reactor monitoring and to understand its capabilities, the National Nuclear Laboratory modelled this graphite moderated and natural uranium fuelled reactor with existing codes used to support Magnox reactor operations and waste management. The 3D multi-physics code PANTHER was used to determine the individual powers of each fuel element (8×6152 during the year and a half period of monitoring based upon reactor records. The WIMS/TRAIL/FISPIN code route was then used to determine the radionuclide inventory of each nuclide on a daily basis in each element. These nuclide inventories were then used with the BTSPEC code to determine the anti-neutrino spectra and source strength using JEFF-3.1.1 data. Finally the anti-neutrino source from the reactor for each day during the year and a half of

  18. The relevance of the vertex bremsstrahlung photon detection in the electron-neutrino (antineutrino) electron scattering experiments at low energy

    CERN Document Server

    Broggini, C; Moretti, M

    1999-01-01

    We discuss the size of the electron-antineutrino electron into electron-antineutrino electron cross section reduction due to the rejection of the events with a vertex bremsstrahlung photon above a certain energy in the final state. In particular we analyze the effect in experiments designed to detect the low energy electron-antineutrino and electron-neutrino from a nuclear reactor and from the Sun. We find that such reduction has to be considered in a relatively high statistic reactor experiment, while it is negligible for pp and 7Be solar neutrino detection.

  19. First Measurement of the Muon Anti-Neutrino Charged Current Quasielastic Double-Differential Cross-Section

    Energy Technology Data Exchange (ETDEWEB)

    Grange, Joseph M. [Univ. of Florida, Gainesville, FL (United States)

    2013-01-01

    This dissertation presents the first measurement of the muon antineutrino charged current quasi-elastic double-differential cross section. These data significantly extend the knowledge of neutrino and antineutrino interactions in the GeV range, a region that has recently come under scrutiny due to a number of conflicting experimental results. To maximize the precision of this measurement, three novel techniques were employed to measure the neutrino background component of the data set. Representing the first measurements of the neutrino contribution to an accelerator-based antineutrino beam in the absence of a magnetic field, the successful execution of these techniques carry implications for current and future neutrino experiments.

  20. Precise measurement of neutrino and anti-neutrino differential cross sections on iron

    Energy Technology Data Exchange (ETDEWEB)

    Tzanov, Martin Mihaylov [Pittsburgh U.

    2005-11-01

    This thesis will present a precise measurement of the differential cross section for charged current neutrino and anti-neutrino scattering from iron. The NuTeV experiment took data during 1996-97 and collected 8.6 10 º and 2.4 10 º charged-current (CC) interactions. The experiment combines sign-selected neutrino and antineutrino beams and the upgraded CCFR iron-scintillator neutrino detector. A precision continuous calibration beam was used to determine the muon and hadron energy scales to a precision of about a factor of two better than previous experiments. The structure functions F (x,Q2) and xF3(x,Q2) are extracted and compared with theory and previous measurements.

  1. Study for Reactor Monitoring using Anti-neutrino Detection in the Neos experiment

    Energy Technology Data Exchange (ETDEWEB)

    Han, Bo Young; Sun, Gwang Min [KAERI, Daejeon (Korea, Republic of); Jeon, Eun Ju [ISB, Daejeon (Korea, Republic of); and others

    2016-05-15

    In this study we describe a feasibility study of reactor monitoring using antineutrino detection in the Neutrino Experiment for Oscillation at Short baseline (NEOS) at Hanbit power plant. Recently, in the perspective of nonproliferation issues and misuse of nuclear energy as a fast-growing nuclear energy industry, the application of anti-neutrino measurement has been proposed and the feasibility studies has been carried out as a novel technology for monitoring the burning process of nuclear power reactor. The NEOS detector with 1000 L Gd-doped liquid scintillator was installed in tendon gallery at Hanbit power station unit 5 and has been collecting close to 2000 IBD events per day with the signal to noise ratio of ∼ 20. As a preliminary result, we demonstrate the possibility of monitoring nuclear power reactor with the IBD counting rate during reactor power ON, ramping up, and OFF.

  2. Determination of the fission coefficients in thermal nuclear reactors for antineutrino detection

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Lenilson M. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Cabral, Ronaldo G., E-mail: rgcabral@ime.eb.b [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Anjos, Joao C.C. dos, E-mail: janjos@cbpf.b [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Dept. GLN - G

    2011-07-01

    The nuclear reactors in operation periodically need to change their fuel. It is during this process that these reactors are more vulnerable to occurring of several situations of fuel diversion, thus the monitoring of the nuclear installations is indispensable to avoid events of this nature. Considering this fact, the most promissory technique to be used for the nuclear safeguard for the nonproliferation of nuclear weapons, it is based on the detection and spectroscopy of antineutrino from fissions that occur in the nuclear reactors. The detection and spectroscopy of antineutrino, they both depend on the single contribution for the total number of fission of each actinide in the core reactor, these contributions receive the name of fission coefficients. The goal of this research is to show the computational and mathematical modeling used to determinate these coefficients for PWR reactors. (author)

  3. Shifts of neutrino oscillation parameters in reactor antineutrino experiments with non-standard interactions

    Directory of Open Access Journals (Sweden)

    Yu-Feng Li

    2014-11-01

    Full Text Available We discuss reactor antineutrino oscillations with non-standard interactions (NSIs at the neutrino production and detection processes. The neutrino oscillation probability is calculated with a parametrization of the NSI parameters by splitting them into the averages and differences of the production and detection processes respectively. The average parts induce constant shifts of the neutrino mixing angles from their true values, and the difference parts can generate the energy (and baseline dependent corrections to the initial mass-squared differences. We stress that only the shifts of mass-squared differences are measurable in reactor antineutrino experiments. Taking Jiangmen Underground Neutrino Observatory (JUNO as an example, we analyze how NSIs influence the standard neutrino measurements and to what extent we can constrain the NSI parameters.

  4. A Comparison Framework for Reactor Anti-Neutrino Detectors in Near-Field Nuclear Safeguards Applications

    Energy Technology Data Exchange (ETDEWEB)

    Mendenhall, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bowden, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brodsky, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bernstein, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-11-03

    Electron anti-neutrino ( e) detectors can support nuclear safeguards, from reactor monitoring to spent fuel characterization. In recent years, the scientific community has developed multiple detector concepts, many of which have been prototyped or deployed for specific measurements by their respective collaborations. However, the diversity of technical approaches, deployment conditions, and analysis techniques complicates direct performance comparison between designs. We have begun development of a simulation framework to compare and evaluate existing and proposed detector designs for nonproliferation applications in a uniform manner. This report demonstrates the intent and capabilities of the framework by evaluating four detector design concepts, calculating generic reactor antineutrino counting sensitivity, and capabilities in a plutonium disposition application example.

  5. First Measurement of one Pion Production in Charged Current Neutrino and Antineutrino events on Argon

    Energy Technology Data Exchange (ETDEWEB)

    Scanavini, Scanavini,Giacomo [Yale U.

    2017-01-01

    This thesis presents a work done in the context of the Fermilab Neutrino Intensity Frontier. In this analysis, the cross section of single charged pion production in charged-current neutrino and antineutrino interactions with the argon nucleus target are measured. These measurements are performed using the Argon Neutrino Test (ArgoNeuT) detector exposed to the Fermilab Neutrino From The Main Injector (NuMI) beam operating in the low energy antineutrino mode. The signal is a charged-current μ interaction in the detector, with exactly one charged pion exiting the target nucleus, with momentum above 100 MeV/c. There shouldn’t be any 0 or kaons in the final state. There is no restriction on other mesons or nucleons. Total and differential cross section measurements are presented. The results are reported in terms of outgoing muon angle and momentum, outgoing pion angle and angle between outgoing pion and muon. The total cross sections, averaged over the flux, are found to be 8.2 ± 0.9 (stat) +0.9 -1.1 (syst) × 10-38 cm2 per argon nuclei and 2.5 ± 0.4 (stat) ± 0.5 (syst) × 10-37 cm2 per argon nuclei for antineutrino and neutrino respectively at a mean neutrino energy of 3.6 GeV (antineutrinos) and 9.6 GeV (neutrinos). This is the first time the single pion production in charged-current interactions cross section is measured on argon nuclei.

  6. Lithium Gadolinium Borate in Plastic Scintillator as an Antineutrino Detection Material

    Science.gov (United States)

    2010-06-01

    commercial reactor stage is fuel assembly inventory accountancy, reactor operator declarations of power and burnup and auditing by the IAEA. Current...of the groups that first established the correlation between reactor antineutrino flux, thermal power, and fuel burnup has proposed a cubic meter...certainly all escape without depositing much energy. The expected ratio for Gd captures to Li or B is hard to calculate as it depends strongly on the

  7. Reactor neutron converter into antineutrinos on base of lithium compounds and their solutions

    International Nuclear Information System (INIS)

    Lyutostanskij, Yu.S.; Lyashchuk, V.I.

    1990-01-01

    A study on the possibility of using various lithium compounds as substances for reactor neutron converter into antineutrinos, was made. It is concluded that heavy water LiOD, LiODxD 2 O, LiD solutions are the most promising ones. They provide for high efficiency with reduction of the required lithium mass (300-350 times maximum) as compared with pure lithium converter

  8. How unequal fluxes of high energy astrophysical neutrinos and antineutrinos can fake new physics

    International Nuclear Information System (INIS)

    Nunokawa, Hiroshi; Panes, Boris; Funchal, Renata Zukanovich

    2016-01-01

    Flavor ratios of very high energy astrophysical neutrinos, which can be studied at the Earth by a neutrino telescope such as IceCube, can serve to diagnose their production mechanism at the astrophysical source. The flavor ratios for neutrinos and antineutrinos can be quite different as we do not know how they are produced in the astrophysical environment. Due to this uncertainty the neutrino and antineutrino flavor ratios at the Earth also could be quite different. Nonetheless, it is generally assumed that flavor ratios for neutrinos and antineutrinos are the same at the Earth, in fitting the high energy astrophysical neutrino data. This is a reasonable assumption for the limited statistics for the data we currently have. However, in the future the fit must be performed allowing for a possible discrepancy in these two fractions in order to be able to disentangle different production mechanisms at the source from new physics in the neutrino sector. To reinforce this issue, in this work we show that a wrong assumption about the distribution of neutrino flavor ratios at the Earth may indeed lead to misleading interpretations of IceCube results.

  9. How unequal fluxes of high energy astrophysical neutrinos and antineutrinos can fake new physics

    Energy Technology Data Exchange (ETDEWEB)

    Nunokawa, Hiroshi [Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, C.P. 38071, 22452-970, Rio de Janeiro (Brazil); Panes, Boris; Funchal, Renata Zukanovich [Instituto de Física, Universidade de São Paulo, C.P. 66.318, 05315-970 São Paulo (Brazil)

    2016-10-21

    Flavor ratios of very high energy astrophysical neutrinos, which can be studied at the Earth by a neutrino telescope such as IceCube, can serve to diagnose their production mechanism at the astrophysical source. The flavor ratios for neutrinos and antineutrinos can be quite different as we do not know how they are produced in the astrophysical environment. Due to this uncertainty the neutrino and antineutrino flavor ratios at the Earth also could be quite different. Nonetheless, it is generally assumed that flavor ratios for neutrinos and antineutrinos are the same at the Earth, in fitting the high energy astrophysical neutrino data. This is a reasonable assumption for the limited statistics for the data we currently have. However, in the future the fit must be performed allowing for a possible discrepancy in these two fractions in order to be able to disentangle different production mechanisms at the source from new physics in the neutrino sector. To reinforce this issue, in this work we show that a wrong assumption about the distribution of neutrino flavor ratios at the Earth may indeed lead to misleading interpretations of IceCube results.

  10. Resonant antineutrino induced electron capture with low energy bound-beta beams

    Energy Technology Data Exchange (ETDEWEB)

    Oldeman, R.G.C.; Meloni, M.; Saitta, B. [Universita degli Studi di Cagliari (Italy); INFN, Sezione di Cagliari, Dipartimento di Fisica, Cagliari (Italy)

    2010-01-15

    Antineutrino induced electron capture is a resonant process that can have a large cross-section for beams of monochromatic antineutrinos. We calculate the cross-section of this process and investigate an experimental setup where monochromatic antineutrinos are produced from the bound-beta decay of fully ionized radioactive atoms in a storage ring. If the energy between the source and the target is well matched, the cross-sections can be significantly larger than the cross-sections of commonly used non-resonant processes. The rate that can be achieved at a small distance between the source and two targets of 10{sup 3} kg is up to one interaction per 8.3.10{sup 18} decaying atoms. For a source-target distance corresponding to the first atmospheric neutrino oscillation maximum, the largest rate is one interaction per 3.2.10{sup 21} decaying atoms, provided that extremely stringent monochromaticity conditions (10{sup -7} or better) are achieved in future ion beams. (orig.)

  11. Measurement of the electroweak coupling of neutrinos and antineutrinos on electrons

    International Nuclear Information System (INIS)

    Jonker, M.

    1983-01-01

    This thesis describes the analysis of the events induced by elastic scattering of neutrinos and antineutrinos on electrons and interprets the results in terms of the coupling strength of (anti)neutrino on electrons. The data for this analysis were obtained with the electronic calorimeter of the CHARM (Amsterdam, Cern, Hamburg, Moscow, Rome) collaboration during the wide band neutrino beam exposures of 1979, 1980 and 1981 in the neutrino facility of the SPS (Super Proton Synchrotron) at CERN (Conseil Europeen pour la Recherche Nucleaire, Geneva, Switzerland). In chapter 1 a historical overview of the early neutrino physics and a description of the phenomenological Lagrangian is given, followed by an introduction to the electroweak unification model. The neutrino detector of the CHARM collaboration is described in chapter 2. Chapter 3 deals with the on-line monitoring system of this detector which has been under the responsibility of the author. The wide band neutrino facility of the CERN SPS is described in chapter 4, followed by a discussion of the experimental method to measure the neutrino energy spectra of the neutrino beams. The electromagnetic shower development process is reviewed in chapter 5 and is followed by a description of the technique that was used to separate showers of electromagnetic and hadronic origin. Chapter 6 discusses the observed signal of the (anti)neutrinos scattering on electrons and interprets these events in terms of the parameters related to the strength of the coupling of neutrinos to electrons. (Auth.)

  12. Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay.

    Science.gov (United States)

    An, F P; Balantekin, A B; Band, H R; Bishai, M; Blyth, S; Cao, D; Cao, G F; Cao, J; Chan, Y L; Chang, J F; Chang, Y; Chen, H S; Chen, Q Y; Chen, S M; Chen, Y X; Chen, Y; Cheng, J; Cheng, Z K; Cherwinka, J J; Chu, M C; Chukanov, A; Cummings, J P; Ding, Y Y; Diwan, M V; Dolgareva, M; Dove, J; Dwyer, D A; Edwards, W R; Gill, R; Gonchar, M; Gong, G H; Gong, H; Grassi, M; Gu, W Q; Guo, L; Guo, X H; Guo, Y H; Guo, Z; Hackenburg, R W; Hans, S; He, M; Heeger, K M; Heng, Y K; Higuera, A; Hsiung, Y B; Hu, B Z; Hu, T; Huang, E C; Huang, H X; Huang, X T; Huang, Y B; Huber, P; Huo, W; Hussain, G; Jaffe, D E; Jen, K L; Ji, X P; Ji, X L; Jiao, J B; Johnson, R A; Jones, D; Kang, L; Kettell, S H; Khan, A; Kohn, S; Kramer, M; Kwan, K K; Kwok, M W; Langford, T J; Lau, K; Lebanowski, L; Lee, J; Lee, J H C; Lei, R T; Leitner, R; Leung, J K C; Li, C; Li, D J; Li, F; Li, G S; Li, Q J; Li, S; Li, S C; Li, W D; Li, X N; Li, X Q; Li, Y F; Li, Z B; Liang, H; Lin, C J; Lin, G L; Lin, S; Lin, S K; Lin, Y-C; Ling, J J; Link, J M; Littenberg, L; Littlejohn, B R; Liu, J L; Liu, J C; Loh, C W; Lu, C; Lu, H Q; Lu, J S; Luk, K B; Ma, X Y; Ma, X B; Ma, Y Q; Malyshkin, Y; Martinez Caicedo, D A; McDonald, K T; McKeown, R D; Mitchell, I; Nakajima, Y; Napolitano, J; Naumov, D; Naumova, E; Ngai, H Y; Ochoa-Ricoux, J P; Olshevskiy, A; Pan, H-R; Park, J; Patton, S; Pec, V; Peng, J C; Pinsky, L; Pun, C S J; Qi, F Z; Qi, M; Qian, X; Qiu, R M; Raper, N; Ren, J; Rosero, R; Roskovec, B; Ruan, X C; Steiner, H; Stoler, P; Sun, J L; Tang, W; Taychenachev, D; Treskov, K; Tsang, K V; Tull, C E; Viaux, N; Viren, B; Vorobel, V; Wang, C H; Wang, M; Wang, N Y; Wang, R G; Wang, W; Wang, X; Wang, Y F; Wang, Z; Wang, Z; Wang, Z M; Wei, H Y; Wen, L J; Whisnant, K; White, C G; Whitehead, L; Wise, T; Wong, H L H; Wong, S C F; Worcester, E; Wu, C-H; Wu, Q; Wu, W J; Xia, D M; Xia, J K; Xing, Z Z; Xu, J L; Xu, Y; Xue, T; Yang, C G; Yang, H; Yang, L; Yang, M S; Yang, M T; Yang, Y Z; Ye, M; Ye, Z; Yeh, M; Young, B L; Yu, Z Y; Zeng, S; Zhan, L; Zhang, C; Zhang, C C; Zhang, H H; Zhang, J W; Zhang, Q M; Zhang, R; Zhang, X T; Zhang, Y M; Zhang, Y X; Zhang, Y M; Zhang, Z J; Zhang, Z Y; Zhang, Z P; Zhao, J; Zhou, L; Zhuang, H L; Zou, J H

    2017-06-23

    The Daya Bay experiment has observed correlations between reactor core fuel evolution and changes in the reactor antineutrino flux and energy spectrum. Four antineutrino detectors in two experimental halls were used to identify 2.2 million inverse beta decays (IBDs) over 1230 days spanning multiple fuel cycles for each of six 2.9 GW_{th} reactor cores at the Daya Bay and Ling Ao nuclear power plants. Using detector data spanning effective ^{239}Pu fission fractions F_{239} from 0.25 to 0.35, Daya Bay measures an average IBD yield σ[over ¯]_{f} of (5.90±0.13)×10^{-43}  cm^{2}/fission and a fuel-dependent variation in the IBD yield, dσ_{f}/dF_{239}, of (-1.86±0.18)×10^{-43}  cm^{2}/fission. This observation rejects the hypothesis of a constant antineutrino flux as a function of the ^{239}Pu fission fraction at 10 standard deviations. The variation in IBD yield is found to be energy dependent, rejecting the hypothesis of a constant antineutrino energy spectrum at 5.1 standard deviations. While measurements of the evolution in the IBD spectrum show general agreement with predictions from recent reactor models, the measured evolution in total IBD yield disagrees with recent predictions at 3.1σ. This discrepancy indicates that an overall deficit in the measured flux with respect to predictions does not result from equal fractional deficits from the primary fission isotopes ^{235}U, ^{239}Pu, ^{238}U, and ^{241}Pu. Based on measured IBD yield variations, yields of (6.17±0.17) and (4.27±0.26)×10^{-43}  cm^{2}/fission have been determined for the two dominant fission parent isotopes ^{235}U and ^{239}Pu. A 7.8% discrepancy between the observed and predicted ^{235}U yields suggests that this isotope may be the primary contributor to the reactor antineutrino anomaly.

  13. Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

    Science.gov (United States)

    An, F. P.; Balantekin, A. B.; Band, H. R.; Bishai, M.; Blyth, S.; Cao, D.; Cao, G. F.; Cao, J.; Chan, Y. L.; Chang, J. F.; Chang, Y.; Chen, H. S.; Chen, Q. Y.; Chen, S. M.; Chen, Y. X.; Chen, Y.; Cheng, J.; Cheng, Z. K.; Cherwinka, J. J.; Chu, M. C.; Chukanov, A.; Cummings, J. P.; Ding, Y. Y.; Diwan, M. V.; Dolgareva, M.; Dove, J.; Dwyer, D. A.; Edwards, W. R.; Gill, R.; Gonchar, M.; Gong, G. H.; Gong, H.; Grassi, M.; Gu, W. Q.; Guo, L.; Guo, X. H.; Guo, Y. H.; Guo, Z.; Hackenburg, R. W.; Hans, S.; He, M.; Heeger, K. M.; Heng, Y. K.; Higuera, A.; Hsiung, Y. B.; Hu, B. Z.; Hu, T.; Huang, E. C.; Huang, H. X.; Huang, X. T.; Huang, Y. B.; Huber, P.; Huo, W.; Hussain, G.; Jaffe, D. E.; Jen, K. L.; Ji, X. P.; Ji, X. L.; Jiao, J. B.; Johnson, R. A.; Jones, D.; Kang, L.; Kettell, S. H.; Khan, A.; Kohn, S.; Kramer, M.; Kwan, K. K.; Kwok, M. W.; Langford, T. J.; Lau, K.; Lebanowski, L.; Lee, J.; Lee, J. H. C.; Lei, R. T.; Leitner, R.; Leung, J. K. C.; Li, C.; Li, D. J.; Li, F.; Li, G. S.; Li, Q. J.; Li, S.; Li, S. C.; Li, W. D.; Li, X. N.; Li, X. Q.; Li, Y. F.; Li, Z. B.; Liang, H.; Lin, C. J.; Lin, G. L.; Lin, S.; Lin, S. K.; Lin, Y.-C.; Ling, J. J.; Link, J. M.; Littenberg, L.; Littlejohn, B. R.; Liu, J. L.; Liu, J. C.; Loh, C. W.; Lu, C.; Lu, H. Q.; Lu, J. S.; Luk, K. B.; Ma, X. Y.; Ma, X. B.; Ma, Y. Q.; Malyshkin, Y.; Martinez Caicedo, D. A.; McDonald, K. T.; McKeown, R. D.; Mitchell, I.; Nakajima, Y.; Napolitano, J.; Naumov, D.; Naumova, E.; Ngai, H. Y.; Ochoa-Ricoux, J. P.; Olshevskiy, A.; Pan, H.-R.; Park, J.; Patton, S.; Pec, V.; Peng, J. C.; Pinsky, L.; Pun, C. S. J.; Qi, F. Z.; Qi, M.; Qian, X.; Qiu, R. M.; Raper, N.; Ren, J.; Rosero, R.; Roskovec, B.; Ruan, X. C.; Steiner, H.; Stoler, P.; Sun, J. L.; Tang, W.; Taychenachev, D.; Treskov, K.; Tsang, K. V.; Tull, C. E.; Viaux, N.; Viren, B.; Vorobel, V.; Wang, C. H.; Wang, M.; Wang, N. Y.; Wang, R. G.; Wang, W.; Wang, X.; Wang, Y. F.; Wang, Z.; Wang, Z.; Wang, Z. M.; Wei, H. Y.; Wen, L. J.; Whisnant, K.; White, C. G.; Whitehead, L.; Wise, T.; Wong, H. L. H.; Wong, S. C. F.; Worcester, E.; Wu, C.-H.; Wu, Q.; Wu, W. J.; Xia, D. M.; Xia, J. K.; Xing, Z. Z.; Xu, J. L.; Xu, Y.; Xue, T.; Yang, C. G.; Yang, H.; Yang, L.; Yang, M. S.; Yang, M. T.; Yang, Y. Z.; Ye, M.; Ye, Z.; Yeh, M.; Young, B. L.; Yu, Z. Y.; Zeng, S.; Zhan, L.; Zhang, C.; Zhang, C. C.; Zhang, H. H.; Zhang, J. W.; Zhang, Q. M.; Zhang, R.; Zhang, X. T.; Zhang, Y. M.; Zhang, Y. X.; Zhang, Y. M.; Zhang, Z. J.; Zhang, Z. Y.; Zhang, Z. P.; Zhao, J.; Zhou, L.; Zhuang, H. L.; Zou, J. H.; Daya Bay Collaboration

    2017-06-01

    The Daya Bay experiment has observed correlations between reactor core fuel evolution and changes in the reactor antineutrino flux and energy spectrum. Four antineutrino detectors in two experimental halls were used to identify 2.2 million inverse beta decays (IBDs) over 1230 days spanning multiple fuel cycles for each of six 2.9 G Wth reactor cores at the Daya Bay and Ling Ao nuclear power plants. Using detector data spanning effective 239Pu fission fractions F239 from 0.25 to 0.35, Daya Bay measures an average IBD yield σ¯f of (5.90 ±0.13 )×10-43 cm2/fission and a fuel-dependent variation in the IBD yield, d σf/d F239, of (-1.86 ±0.18 )×10-43 cm2/fission . This observation rejects the hypothesis of a constant antineutrino flux as a function of the 239Pu fission fraction at 10 standard deviations. The variation in IBD yield is found to be energy dependent, rejecting the hypothesis of a constant antineutrino energy spectrum at 5.1 standard deviations. While measurements of the evolution in the IBD spectrum show general agreement with predictions from recent reactor models, the measured evolution in total IBD yield disagrees with recent predictions at 3.1 σ . This discrepancy indicates that an overall deficit in the measured flux with respect to predictions does not result from equal fractional deficits from the primary fission isotopes 235U, 239Pu, 238U, and 241Pu. Based on measured IBD yield variations, yields of (6.17 ±0.17 ) and (4.27 ±0.26 )×10-43 cm2 /fission have been determined for the two dominant fission parent isotopes 235U and 239Pu. A 7.8% discrepancy between the observed and predicted 235U yields suggests that this isotope may be the primary contributor to the reactor antineutrino anomaly.

  14. Experimental study of invariance violations in neutrino and antineutrino reactions at high energy

    International Nuclear Information System (INIS)

    Blaes, R.

    1983-06-01

    This work is dedicated to the study of the structure functions in neutrino-nucleon interactions and to the interpretation of observed violations of scaling invariance. The first chapter describes the experimental setting, the Cargamelle cloud chamber has been used. The second chapter presents the data analysis, the event selection methodology, the muon identification and the energy correction that takes into account the non-detected particles. We also present the bi-dimensional x and q 2 distribution of events that is necessary to the determination of the structure functions. In the third chapter we detail the theoretical basis of our analysis: we define relevant kinematic variables and we discuss the scale invariance in the light of the quark-parton model. The violations of the scale invariance are considered first in the formalism of quantum chromodynamics and then in the view of higher twist or mass corrections. The fourth chapter deals with the experimental determination of the structure functions and of the violations of the scaling invariance. (A.C.)

  15. Properties of the hadronic system produced in antineutrino proton interactions

    International Nuclear Information System (INIS)

    Musgrave, B.

    1979-01-01

    The separation of the hadronic system produced in anti νp charged-current reactions into the current and target fragmentation components is discussed. The current fragments show properties in good qualitative agreement with the expectations of the naive quark-parton model. In particular, there is no evidence for either a Q 2 - or X/sub BJ/-dependence of the fragmentation functions. 7 references

  16. Angular distributions of neutrino and antineutrino scatterings by electrons and gauge models

    International Nuclear Information System (INIS)

    Dass, G.V.

    1976-01-01

    Assuming a nonderivative point interaction, and Born approximation, the complete angular distributions for the scatterings of neutrinos and antineutrinos by electrons are obtained from only simple general considerations, without explicit calculation; generalisation to parton targets is noted. Two pairs of simple constraints on the angular distributions can be violated only if the interaction has a helicity-flipping component; this can serve to disfavour the large class of models which are purely helicity-conserving. Comparison is made with some explicit calculations done for some special cases of some of the results. (author)

  17. Experimental study of the nucleon longitudinal structure function in charged-current neutrino and antineutrino interactions

    International Nuclear Information System (INIS)

    Bergsma, F.; Dorenbosch, J.; Jonker, M.; Nieuwenhuis, C.; Allaby, J.V.; Amaldi, U.; Barbiellini, G.; Barone, L.; Capone, A.; Flegel, W.; Metcalf, M.; Panman, J.; Winter, K.; Abt, I.; Aspiazu, J.; Buesser, F.W.; Daumann, H.; Gall, P.D.; Metz, E.; Niebergall, F.; Ranitzsch, K.H.; Staehelin, P.; Baroncelli, A.; Bosio, C.; Tortora, L.; Borgia, B.; Diemoz, M.; Dore, U.; Ferroni, F.; Longo, E.; Luminari, L.; Monacelli, P.; De Notaristefani, F.; Pistilli, P.; Santoni, C.; Valente, V.

    1984-01-01

    The x dependence of the longitudinal structure function Fsub(L) was determined with the CHARM neutrino detector exposed to neutrino and antineutrino wide-band beams of the CERN 400 GeV SPS. The results show a clear deviation from the Callan-Gross relation. The amount and the x dependence of this deviation are in agreement with the contribution coming from a finite transverse momentum of the partons in the nucleon if both the intrinsic and perturbative QCD terms are taken into account. (orig.)

  18. Neutral current (anti)neutrino scattering: Relativistic mean field and superscaling predictions

    International Nuclear Information System (INIS)

    González-Jiménez, R.; Ivanov, M.V.; Barbaro, M.B.; Caballero, J.A.; Udias, J.M.

    2013-01-01

    We evaluate the neutral current quasi-elastic neutrino cross section within two nuclear models: the SuSA model, based on the superscaling behavior of electron scattering data, and the RMF model, based on relativistic mean field theory. We also estimate the ratio (νp→νp)/(νN→νN) and compare with the MiniBooNE experimental data, performing a fit of the parameters M A and g A (s) within the two models. Finally, we present our predictions for antineutrino scattering.

  19. Measurement of the neutron and proton structure functions from neutrino and antineutrino scattering in deuterium

    Science.gov (United States)

    Allasia, D.; Angelini, C.; Baldini, A.; Barlag, S.; Bertanza, L.; Bigi, A.; Bisi, V.; Bobisut, F.; Bolognese, T.; Borg, A.; Calimani, E.; Capiluppi, P.; Casali, R.; Ciampolillo, S.; Derkaoui, J.; Faccini-Turluer, M. L.; Fantechi, R.; Flaminio, V.; Frodesen, A. G.; Gamba, D.; Giacomelli, G.; Graziani, G.; Halsteinslid, A.; Hornaes, A.; Huzita, H.; Jongejans, B.; Lippi, I.; Loreti, M.; Louedec, C.; Mandrioli, G.; Marzari-Chiesa, A.; Nappi, A.; Pazzi, R.; Pierazzini, G. M.; Riccati, L.; Romero, A.; Rossi, A. M.; Sconza, A.; Serra-Lugaresi, P.; Tenner, A.; van Apeldoorn, G. W.; van Dam, P.; Vignaud, D.; Visser, C.; Wigmans, R.

    1984-02-01

    Data from an exposure of the BEBC bubble chamber filled with deuterium to neutrino and antineutrino wide band beams have been used to extract the x dependence of the structure functions for scattering on protons and neutrons and the fractional momentum distributions of the valence quarks and the antiquarks of different flavours. The difference F n2 - F p2 is compared with recent data from high energy μD scattering. A result is also obtained on the sum rule giving the difference between the number of up and down quarks in the nucleon.

  20. New (anti)neutrino results from the T2K experiment on CP violation in the lepton sector

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    T2K is a long-baseline neutrino experiment in which a muon neutrino beam produced by J-PARC in Tokai is sent 295 km across Japan to the Super-Kamiokande detector, to study neutrino oscillations via the disappearance of muon neutrinos and the appearance of electron neutrinos. Since the start of operations in 2010, T2K has conclusively observed muon neutrino to electron neutrino oscillations, opening the door to the observation of CP violation in neutrino mixing, and performed the most precise measurement of the muon neutrino disappearance parameters. In a joint analysis between these two modes, T2K placed its first constraints on the CP-violating phase delta. Starting in 2014, T2K has been running primarily with an antineutrino beam in order to study the corresponding antineutrino oscillations, resulting in leading measurements of the muon antineutrino disappearance parameters. The joint analysis of neutrino and antineutrino data indicates that CP-conserving parameters lie outside the 90% confidence interval....

  1. Measurement of the Antineutrino Double-Differential Charged-Current Quasi-Elastic Scattering Cross Section at MINERvA

    Energy Technology Data Exchange (ETDEWEB)

    Patrick, Cheryl [Northwestern U.

    2016-01-01

    Next-generation neutrino oscillation experiments, such as DUNE and Hyper-Kamiokande, hope to measure charge-parity (CP) violation in the lepton sector. In order to do this, they must dramatically reduce their current levels of uncertainty, particularly those due to neutrino-nucleus interaction models. As CP violation is a measure of the difference between the oscillation properties of neutrinos and antineutrinos, data about how the less-studied antineutrinos interact is especially valuable. We present the MINERvA experiment's first double-differential scattering cross sections for antineutrinos on scintillator, in the few-GeV range relevant to experiments such as DUNE and NOvA. We also present total antineutrino-scintillator quasi-elastic cross sections as a function of energy, which we compare to measurements from previous experiments. As well as being useful to help reduce oscillation experiments' uncertainty, our data can also be used to study the prevalence of various cor relation and final-state interaction effects within the nucleus. We compare to models produced by different model generators, and are able to draw first conclusions about the predictions of these models.

  2. Measurement of Neutrino and Antineutrino Total Charged-Current Cross Sections on Carbon with MINERvA

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Lu [Univ. of Pittsburgh, PA (United States)

    2017-01-01

    This thesis presents a measurement of charged-current inclusive cross sections of muon neutrino and antineutrino interaction on carbon, and antineutrino to neutrino cross section ratio, r, in the energy range 2 - 22 GeV, with data collected in the MINERA experiment. The dataset corresponds to an exposure of 3.2 x 1020 protons on target (POT) for neutrinos and 1.01020 POT for antineutrinos. Measurement of neutrino and antineutrino charged-current inclusive cross sections provides essential constraints for future long baseline neutrino oscillation experiment at a few GeV energy range. Our measured antineutrino cross section has an uncertainty in the range 6.1% - 10.5% and is the most precise measurement below 6 GeV to date. The measured r has an uncertainty of 5.0% - 7.5%. This is the rst measurement below 6 GeV since Gargamelle in 1970s. The cross sections are measured as a function of neutrino energy by dividing the eciency corrected charged-current sample with extracted uxes. Fluxes are obtained using the low- method, which uses low hadronic energy subsamples of charged-current inclusive sample to extract ux. Measured cross sections show good agreement with the prediction of neutrino interaction models above 7 GeV, and are about 10% below the model below 7 GeV. The measured r agrees with the GENIE model [1] over the whole energy region. The measured cross sections and r are compared with world data.

  3. Measurement of muon neutrino and antineutrino induced single neutral pion production cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Colin E. [Yale Univ., New Haven, CT (United States)

    2011-05-01

    Elucidating the nature of neutrino oscillation continues to be a goal in the vanguard of the efforts of physics experiment. As neutrino oscillation searches seek an increasingly elusive signal, a thorough understanding of the possible backgrounds becomes ever more important. Measurements of neutrino-nucleus interaction cross sections are key to this understanding. Searches for νμ → νe oscillation - a channel that may yield insight into the vanishingly small mixing parameter θ13, CP violation, and the neutrino mass hierarchy - are particularly susceptible to contamination from neutral current single π0 (NC 1π0) production. Unfortunately, the available data concerning NC 1π0 production are limited in scope and statistics. Without satisfactory constraints, theoretical models of NC 1π0 production yield substantially differing predictions in the critical Eν ~ 1 GeV regime. Additional investigation of this interaction can ameliorate the current deficiencies. The Mini Booster Neutrino Experiment (MiniBooNE) is a short-baseline neutrino oscillation search operating at the Fermi National Accelerator Laboratory (Fermilab). While the oscillation search is the principal charge of the MiniBooNE collaboration, the extensive data (~ 106 neutrino events) offer a rich resource with which to conduct neutrino cross section measurements. This work concerns the measurement of both neutrino and antineutrino NC 1π0 production cross sections at MiniBooNE. The size of the event samples used in the analysis exceeds that of all other similar experiments combined by an order of magnitude. We present the first measurements of the absolute NC 1π0 cross section as well as the first differential cross sections in both neutrino and antineutrino mode. Specifically, we measure single differential cross sections with respect to pion momentum and pion angle. We find the

  4. Calorimetric measurement of the SOX anti-neutrino source for sterile neutrino search

    Energy Technology Data Exchange (ETDEWEB)

    Altenmueller, Konrad; Agostini, Matteo; Papp, Laszlo; Schoenert, Stefan [Physik Department and Excellence Cluster Universe, Technische Universitaet Muenchen (Germany); Collaboration: Borexino-Collaboration

    2015-07-01

    A thermal calorimeter is under development to measure with <1% accuracy the heat release of the Cerium anti-neutrino source for the SOX experiment, which is looking for eV-scale sterile neutrinos. The heat release is proportional to the source activity and thus to the emitted neutrino flux, which is an important parameter of the experiment. The calorimeter design is based on a copper heat exchanger mounted around the source with integrated water lines for the heat extraction. Heat loss through conduction and radiation is minimized by suspending the set-up through Kevlar ropes and inserting it inside a thermalized vacuum tank with radiation shields. The device is currently being assembled and tested at TUM in Garching.

  5. Reactions probing effects of quark clusters in nuclei

    International Nuclear Information System (INIS)

    Lassila, K.E.; Sukhatme, U.P.

    1988-01-01

    We study signatures of quark clusters in reactions which probe quarks in nuclei. We examine the EMC effect and use physical arguments to establish features of valence and ocean parton distributions in multiquark clusters. We predict from these distributions ratios of structure functions and cross sections measured with neutrino, antineutrinos and proton beams. It appears that a unique determination of the source of the EMC effect will be possible. 6 refs., 4 figs

  6. Experimental study of the nucleon structure functions and of the gluon distribution from charged-current neutrino and antineutrino interactions

    International Nuclear Information System (INIS)

    Bergsma, F.; Dorenbosch, J.; Jonker, M.; Nieuwenhuis, C.; Udo, F.; Allaby, J.V.; Amaldi, U.; Barbiellini, G.; Barone, L.; Capone, A.; Flegel, W.; Metcalf, M.; Panman, J.; Winter, K.; Abt, I.; Aspiazu, J.; Buesser, F.W.; Daumann, H.; Gall, P.D.; Metz, E.; Niebergall, F.; Ranitzsch, K.H.; Staehelin, P.

    1983-01-01

    Inclusive neutrino and antineutrino charged current interactions were studied in the CHARM detector exposed to neutrino and antineutrino Wide Band Beams of the CERN 400 GeV SPS. The x and Q 2 dependence of the structure functions F 2 and xF 3 and of the antiquark momentum distribution q were determined. The data have been interpreted in terms of QCD theory using the Furmanski-Petronzio method. In this way we have determined #betta#sub(LO)=[190 + 70 sub(-40)(stat)+-70 (syst.)] MeV and the structure functions of quarks and gluons without specific assumptions on their analytic dependence. The results agree with previous experiments which relied on model assumptions in the analysis. We conclude that the model independent simultaneous analysis of the xF 3 , F 2 , anti q structure functions gives a more reliable determination of the gluon distribution in the nucleon. (orig.)

  7. Measurement of total and differential cross sections of neutrino and antineutrino coherent π± production on carbon

    Science.gov (United States)

    Mislivec, A.; Higuera, A.; Aliaga, L.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Budd, H.; Caceres v., G. F. R.; Cai, T.; Martinez Caicedo, D. A.; Carneiro, M. F.; Chavarria, E.; da Motta, H.; Dytman, S. A.; Díaz, G. A.; Felix, J.; Fields, L.; Fine, R.; Gago, A. M.; Galindo, R.; Gallagher, H.; Ghosh, A.; Gran, R.; Harris, D. A.; Hurtado, K.; Jena, D.; Kleykamp, J.; Kordosky, M.; Le, T.; Maher, E.; Manly, S.; Mann, W. A.; Marshall, C. M.; McFarland, K. S.; Messerly, B.; Miller, J.; Morfín, J. G.; Mousseau, J.; Naples, D.; Nelson, J. K.; Nguyen, C.; Norrick, A.; Nuruzzaman, Paolone, V.; Perdue, G. N.; Ramírez, M. A.; Ransome, R. D.; Ray, H.; Ren, L.; Rimal, D.; Rodrigues, P. A.; Ruterbories, D.; Schellman, H.; Solano Salinas, C. J.; Sultana, M.; Sánchez Falero, S.; Tagg, N.; Valencia, E.; Wospakrik, M.; Yaeggy, B.; Zavala, G.; MinerνA Collaboration

    2018-02-01

    Neutrino induced coherent charged pion production on nuclei, ν¯ μA →μ±π∓A , is a rare inelastic interaction in which the four-momentum squared transferred to the nucleus is nearly zero, leaving it intact. We identify such events in the scintillator of MINERvA by reconstructing |t | from the final state pion and muon momenta and by removing events with evidence of energetic nuclear recoil or production of other final state particles. We measure the total neutrino and antineutrino cross sections as a function of neutrino energy between 2 and 20 GeV and measure flux integrated differential cross sections as a function of Q2 , Eπ, and θπ . The Q2 dependence and equality of the neutrino and antineutrino cross sections at finite Q2 provide a confirmation of Adler's partial conservation of axial current hypothesis.

  8. A feasibility study of boron-loaded liquid scintillator for the detection of electron anti-neutrinos

    CERN Document Server

    Wang, S C; Leung, R W S; Wang, S L; Chang, C Y; Chen Chi Ping; Cheng, K C; Ho, T I; Lai, W P; Liu, H M; Mao, Z P; Shih, I C; Wong, H T; Yu, Z Q

    1999-01-01

    Boron-loaded liquid scintillator offers some potential advantages as a detector for electron anti-neutrinos. A research program was carried out with the objective of developing such scintillators. The crucial feature is the pulse shape discrimination properties following the neutron capture by sup 1 sup 0 B. Results of the R and D efforts are presented. The feasibility and the technical difficulties of carrying out a full-scale neutrino experiment based on this approach are discussed. (author)

  9. SoLid: An innovative anti-neutrino detector for searching oscillations at the SCK• CEN BR2 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, Yamiel, E-mail: yamiel.abreu@uantwerpen.be

    2017-02-11

    The SoLid experiment intends to search for active-to-sterile anti-neutrino oscillations at a very short baseline from the SCK• CEN BR2 research reactor (Mol, Belgium). A novel detector approach to measure reactor anti-neutrinos was developed based on an innovative sandwich of composite polyvinyl-toluene and {sup 6}LiF:ZnS(Ag) scintillators. The system is highly segmented and read out by a network of wavelength shifting fibers and SiPM. High experimental sensitivity can be achieved compared to other standard technologies thanks to the combination of high granularity, good neutron–gamma discrimination using {sup 6}LiF:ZnS(Ag) scintillator and precise localisation of the Inverse Beta Decay products. This technology can be considered as a new generation of an anti-neutrino detector. This compact system requires limited passive shielding and relies on spatial topology to determine the different classes of backgrounds. We will describe the principle of detection and the detector design. Particular focus on the neutron discrimination will be made, as well as on the capability to use cosmic muons for channel equalisation and energy calibration. The performance of the first 288 kg SoLid module (SM1), based on the data taken at BR2 from February to September 2015, will be presented. We will conclude with the next phase, which will start in 2016, and the future plans of the experiment.

  10. SoLid: An innovative anti-neutrino detector for searching oscillations at the SCK•CEN BR2 reactor

    Science.gov (United States)

    Abreu, Yamiel; SoLid Collaboration

    2017-02-01

    The SoLid experiment intends to search for active-to-sterile anti-neutrino oscillations at a very short baseline from the SCK•CEN BR2 research reactor (Mol, Belgium). A novel detector approach to measure reactor anti-neutrinos was developed based on an innovative sandwich of composite polyvinyl-toluene and 6LiF:ZnS(Ag) scintillators. The system is highly segmented and read out by a network of wavelength shifting fibers and SiPM. High experimental sensitivity can be achieved compared to other standard technologies thanks to the combination of high granularity, good neutron-gamma discrimination using 6LiF:ZnS(Ag) scintillator and precise localisation of the Inverse Beta Decay products. This technology can be considered as a new generation of an anti-neutrino detector. This compact system requires limited passive shielding and relies on spatial topology to determine the different classes of backgrounds. We will describe the principle of detection and the detector design. Particular focus on the neutron discrimination will be made, as well as on the capability to use cosmic muons for channel equalisation and energy calibration. The performance of the first 288 kg SoLid module (SM1), based on the data taken at BR2 from February to September 2015, will be presented. We will conclude with the next phase, which will start in 2016, and the future plans of the experiment.

  11. First Anti-neutrino Oscillation Results from the T2K Experiment

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    Neutrinos are some of the most abundant but yet most elusive particles in the universe. They have almost no mass, only interact weakly and relatively little is known about their properties. Furthermore it has been firmly established over the last decade that neutrinos can undergo flavour transitions as mass and flavor eigenstates are not identical. These neutrino oscillations have been studied using natural sources as well as nuclear reactors or with neutrinos produced at accelerators. T2K is a long baseline neutrino oscillation beam that uses a beam of muon (anti-)neutrinos that is directed form J-PARC at the east cost of Japan over a distance of almost 300 km to the SuperKamiokande water Cherenkov detector in the west. The facility is complemented by a near detector complex 280 m downstream of the neutrino production target to characterise the beam and the neutrino interaction dynamics. T2K has taken data with a muon neutrino beam since early 2010 and is studying the disappearance of muon neutrinos as well...

  12. Scintillation light production, propagation and detection in the Stereo reactor antineutrino experiment

    Science.gov (United States)

    Buck, Christian; Lindner, Manfred; Roca, Christian

    2017-09-01

    The Stereo experiment’s detector has been optimized to observe reactor antineutrinos via inverse beta decay within a 1800 liter volume filled with Gadolinium-doped organic liquid scintillator (LS). The main requirements for the scintillator in Stereo are compatibility with detector materials as the acrylic vessels, transparency, light yield, pulse shape discrimination capabilities as well as chemical and optical stability over several years of data taking. With these conditions in mind, the composition of the LS is mainly a mix of 75% LAB, 20%PXE and 5% DIN combined with the two wavelength-shifters PPO and Bis-MSB. The final admixture after the full scale production lead to an attenuation length of more than 5 meters for optical photons of 430 nm. The scintillation light produced in the Gd-loaded target volume and the Gd-free outer crown is detected by 48 eight inch PMTs on top of the detector. A correct performance of the PMTs has been ensured through several tests. Common characteristics for PMTs as gain, single photoelectron peak, time behaviour, dark rate and afterpulse ratio were measured resulting in a complete agreement with the manufacturer values.

  13. Geneva University: Observation of electron-antineutrino disappearance at Daya Bay

    CERN Multimedia

    Université de Genève

    2012-01-01

    GENEVA UNIVERSITY École de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 Genève 4 Tél.: (022) 379 62 73 Fax: (022) 379 69 92 Monday 19 March 2012 COLLOQUE DE PHYSIQUE 5 p.m. - École de Physique, Auditoire Stueckelberg Observation of electron-antineutrino disappearance at Daya Bay  Professor Yifang Wang Institute of High Energy Physics of the Chinese Academy of Sciences Beijing The Daya Bay Reactor Neutrino Experiment, a multinational collaboration operating in the south of China, today reported the first results of its search for the last, most elusive piece of a long-standing puzzle: how is it that neutrinos can appear to vanish as they travel? The surprising answer opens a gateway to a new understanding of fundamental physics and may eventually solve the riddle of why there is far more ordinary matter than antimatter in the Universe today....

  14. Method of fission product beta spectra measurements for predicting reactor anti-neutrino emission

    Energy Technology Data Exchange (ETDEWEB)

    Asner, David M.; Burns, Kimberly A.; Campbell, Luke W.; Greenfield, Bryce A.; Kos, Marek S.; Orrell, John L.; Schram, Malachi; VanDevender, Brent A.; Wood, Lynn S.; Wootan, David W.

    2015-03-01

    The nuclear fission process that occurs in the core of nuclear reactors results in unstable, neutron-rich fission products that subsequently beta decay and emit electron antineutrinos. These reactor neutrinos have served neutrino physics research from the initial discovery of the neutrino to today's precision measurements of neutrino mixing angles. The prediction of the absolute flux and energy spectrum of the emitted reactor neutrinos hinges upon a series of seminal papers based on measurements performed in the 1970s and 1980s. The steadily improving reactor neutrino measurement techniques and recent reconsiderations of the agreement between the predicted and observed reactor neutrino flux motivates revisiting the underlying beta spectra measurements. A method is proposed to use an accelerator proton beam delivered to an engineered target to yield a neutron field tailored to reproduce the neutron energy spectrum present in the core of an operating nuclear reactor. Foils of the primary reactor fissionable isotopes placed in this tailored neutron flux will ultimately emit beta particles from the resultant fission products. Measurement of these beta particles in a time projection chamber with a perpendicular magnetic field provides a distinctive set of systematic considerations for comparison to the original seminal beta spectra measurements. Ancillary measurements such as gamma-ray emission and post-irradiation radiochemical analysis will further constrain the absolute normalization of beta emissions per fission. The requirements for unfolding the beta spectra measured with this method into a predicted reactor neutrino spectrum are explored.

  15. Supernova relic electron neutrinos and anti-neutrinos in future large-scale observatories

    Energy Technology Data Exchange (ETDEWEB)

    Volpe, C.; Welzel, J. [Institut de Physique Nuclueaire, 91 - Orsay (France)

    2007-07-01

    We investigate the signal from supernova relic neutrinos in future large scale observatories, such as MEMPHYS (UNO, Hyper-K), LENA and GLACIER, at present under study. We discuss that complementary information might be gained from the observation of supernova relic electron antineutrinos and neutrinos using the scattering on protons on one hand, and on nuclei such as oxygen, carbon or argon on the other hand. When determining the relic neutrino fluxes we also include, for the first time, the coupling of the neutrino magnetic moment to magnetic fields within the core collapse supernova. We present numerical results on both the relic {nu}{sub e} and {nu}-bar{sub e} fluxes and on the number of events for {nu}{sub e} + C{sup 12}, {nu}{sub e} + O{sup 16}, {nu}{sub e} + Ar{sup 40} and {nu}-bar{sub e} + p for various oscillation scenarios. The observation of supernova relic neutrinos might provide us with unique information on core-collapse supernova explosions, on the star formation history and on neutrino properties, that still remain unknown. (authors)

  16. Messung der Impulsverteilung der Antiquarks im Nukleon aus der inklusiven tiefinelastischen Antineutrino Nukleon Reaktion ueber geladene Stroeme

    CERN Document Server

    Klasen, Hans Peter

    1981-01-01

    In this thesis the antiquark momentum distribution in the nucleus as a function of x and Q2 is determined. This determination is based on the measurement of the differential cross-section at high y for inclusive antineutrino nucleon charged current interactions. The portion of antineutrino scattering off quarks is corrected by the also measured neutrino cross-section. For the measurement of the cross-section 150 000 anti v- und 35 000 v-events, which were produced in the CERN wide band beam, in the energy range from 20 GeV to 160 GeV and 27 000 anti v- and 63 000 v-events measured in the narrow band beam in the energy range from 20 GeV to 200 GeV are used. The measurement was performed with the detector of the CERN-Dortmund-Heidelberg-Saclay collaboration. The detector serves at the same time as target, as hadron energy calorimeter and as muon spectrometer. The measured antiquark momentum distribution shows a strong rise for x<0.1 as a function of Q2. It will be shown that this scaling violation cannot be ...

  17. Search for sub-eV sterile neutrinos in the precision multiple baselines reactor antineutrino oscillation experiments

    Directory of Open Access Journals (Sweden)

    Shu Luo

    2015-10-01

    Full Text Available According to different effects on neutrino oscillations, the unitarity violation in the MNSP matrix can be classified into the direct unitarity violation and the indirect unitarity violation which are induced by the existence of the light and the heavy sterile neutrinos respectively. Of which sub-eV sterile neutrinos are of most interesting. We study in this paper the possibility of searching for sub-eV sterile neutrinos in the precision reactor antineutrino oscillation experiments with three different baselines at around 500 m, 2 km and 60 km. We find that the antineutrino survival probabilities obtained in the reactor experiments are sensitive only to the direct unitarity violation and offer very concentrated sensitivity to the two parameters θ14 and Δm412. If such light sterile neutrinos do exist, the active–sterile mixing angle θ14 could be acquired by the combined rate analysis at all the three baselines and the mass-squared difference Δm412 could be obtained by taking the Fourier transformation to the L/E spectrum. Of course, for such measurements to succeed, both high energy resolution and large statistics are essentially important.

  18. Measurement of the mixing leptonic parameter θ13 at the Double Chooz reactor antineutrino experiment

    International Nuclear Information System (INIS)

    Durand, V.

    2012-01-01

    The Double Chooz experiment aims at measuring the neutrino mixing parameter θ13 by studying the oscillations of de ν-bar e produced by the Chooz nuclear reactors located in France. The experimental concept consists in comparing the signal of two identical 10.3 m 3 detectors, allowing to cancel most of the experimental systematic uncertainties. The near detector, whose goal is the flux normalization and a measurement without oscillation, is expected to be delivered in 2013. The farthest detector from the source is taking data since April 2011 and is sensitive to θ 13 , which is expected to affect both the rate and the shape of the measured de ν-bar e . In this thesis, are first presented the Double Chooz experiment, with its ν-bar e source, its detection method, and the expected signal and backgrounds. In order to perform a selection, important quantities have to be reconstructed, calibrated, and saved in data files. The channel time offsets determination, the energy and vertex reconstruction algorithm CocoReco, the reconstruction packages of the Common Trunk, and the light trees maker Cheetah are especially presented. Concerning the data analysis, all the selection cuts and results for signal and backgrounds are discussed, particularly the multiplicity cut, the multiple off time window method, the lithium veto cut, and the cosmogenic 9 Li background studies. The Double Chooz experiment observed 8,249 de ν-bar e candidates in 227.93 days in its far detector only. The reactor antineutrino flux prediction used the Bugey 4 flux measurement after correction for differences in core composition. The expectation in case of no-oscillation is 8,937 events and this deficit is interpreted as evidence for ν-bar e disappearance. From a rate and shape analysis, is found sin 2 2θ = 0,109± 0,030 (stat) ± 0,025 (syst), with Δm 2 31 = 2,32 x 10 -3 eV 2 , while the no-oscillation hypothesis is even excluded at 2.9 σ. (author) [fr

  19. Anti-Neutrino Charged Current Quasi-Elastic Scattering in MINER$\

    Energy Technology Data Exchange (ETDEWEB)

    Chvojka, Jesse John [Univ. of Rochester, NY (United States)

    2012-01-01

    in neutrino interactions. We present the first cross-section measurement for MINER A, the differential cross-section dσ/dQ2 for muon anti-neutrino CCQE scattering on polystyrene scintillator (CH) as well as comparisons to several final state models.

  20. Strength function of xenon 127 and cross section of 127I(νe, e-)127Xe reaction

    International Nuclear Information System (INIS)

    Lyutostanskij, Yu.S.; Shul'gina, N.B.

    1989-01-01

    The strenght functions S β (E) and the cross section of the reaction ν e + 127 I → e - + 127 Xe were calculated in the framework of the theory of finite Fermi-systems. The results obtained are used to estimate the possibility of using an iodine-xenon detector in the experiments with solar neutrinos and reactor antineutrinos. The advantages of the iodine-xenon detector over the chlorine-argon one are shown. 13 refs.; 6 figs.; 3 tabs

  1. Measurement of Neutrino and Antineutrino Charged-Current Inclusive Cross Sections with the MINERvA Detector

    Energy Technology Data Exchange (ETDEWEB)

    Devan, Joshua D. [College of William and Mary, Williamsburg, VA (United States)

    2015-01-01

    Neutrinos are a nearly massless, neutral particle in the Standard Model that only interact via the weak interaction. Experimental confirmation of neutrino oscillations, in which a neutrino created as a particular type (electron, muon or tau) can be observed as a different type after propagating some distance, earned the 2015 Nobel Prize in Physics. Neutrino oscillation experiments rely on accurate measurements of neutrino interactions with matter, such as that presented here. Neutrinos also provide a unique probe of the nucleus, complementary to electron scattering experiments. This thesis presents a measurement of the charged-current inclusive cross section for muon neutrinos and antineutrinos in the energy range 2 to 50 GeV with the MINERvA detector. MINERvA is a neutrino scattering experiment in the NuMI neutrino beam at Fermilab, near Chicago. A cross section measures the probability of an interaction occurring, measured here as a function of neutrino energy. To extract a cross section from data, the observed rate of interactions is corrected for detector efficiency and divided by the number of scattering nucleons in the target and the flux of neutrinos in the beam. The neutrino flux is determined with the low-$\

  2. Monte-Carlo simulations on the antineutrino detection in heavy ion collisions

    International Nuclear Information System (INIS)

    Zude, E.

    1991-09-01

    Aim of the present thesis was to study, how far a large-area neutron detector with high efficiency operated at the Corporation for Heavy Ion Research in Darmstadt can also by applied for experiments on the sub-threshold antineutron production in heavy ion reactions for the study of the equation of state of highly excited nuclear matter. The experimental part consisted in the partition at the construction, the taking into operation, and the calibration measurements of the target-detector system, as well at the experiments with the LAND detector for the study of the Coulomb excitation of 136 Xe projectiles in the reaction 136 Xe+ 208 Pb at 700 respectively 800 MeV/u. Studies on the suppression of neutron events against antineutron events in the data acquisition in a typical SIS/LAND experiment on the antineutron production in heavy ion collisions were performed. The possibilities available on the level of the hardware trigger for the suppression of (multiple) neutron events were studied. Thereby resulted a reachable suppression factor of ≅ 10 -3 . Studies on the off-line analysis of antineutron events exhibited problems, which base on the high matter density in the detector. (orig./HSI) [de

  3. Measurements of cross-section of charge current inclusive of antineutrino scattering off nucleons using carbon, iron, lead and scintillator at MINER$\

    Energy Technology Data Exchange (ETDEWEB)

    Rakotondravohitra, Laza [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-08-18

    Neutrino physics is one of the most active fields in the domaine of high energy physics during the last century. The need of precise measurement of neutrino-nucleus interactions required by the neutrino oscillation experiments is a an exiting step. These measurements of cross-section are more than essential for neutrino oscillation experiment. Over the year, many measurements from varieties of experiments have been presented. MINERνA is one of the world leaders in measuring cross-section of neutrino and antineutrino -nucleus interactions. MINERνA is a neutrino-nucleus scattering experiment installed in the few-GeV NuMI beam line at Fermilab. In order to study nuclear dependence, MINERνA is endowed with different types of solid nuclear targets as well are liquid targets such as helium and water. This thesis presents measurements of cross-section of antineutrino scattering off nucleons using a variety of solid nuclear targets, carbon, iron, lead and also polystyrene scintillator (CH). The data set of antineutrino used for this analysis was taken between March and July 2010 with a total of 1.60X1020 protons on target. Charged current inclusive interactions were selected by requiring a positive muon and kinematics limitation of acceptance of the muon spectrometer are applied. The analysis requires neutrino energy between 2GeV et 20GeV and the angle of muon θmu < 17degree . The absolute cross-section # as function of neutrino energy and the differential cross-section dσ/ dxbj measured and shown the corresponding systematics for each nuclear targets. Data results are compared with prediction of the models implemented in the neutrino events generators GENIE 2.6.2 used by the experiment.

  4. Reactor anti-neutrinos: measurement of the θ13 leptonic mixing angle and search for potential sterile neutrinos

    International Nuclear Information System (INIS)

    Collin, A.

    2014-01-01

    The Double Chooz experiment aims to measure the θ 13 mixing angle through the disappearance -induced by the oscillation phenomenon - of anti-neutrinos produced by the Chooz nuclear reactors. In order to reduce systematic uncertainties, the experiment relies on the relative comparison of detected signals in two identical liquid scintillator detectors. The near one, giving the normalization of the emitted flux, is currently being built and will be delivered in spring 2014. The far detector, sensitive to θ 13 , is located at about one kilometer and is taking data since 2011. In this first phase of the experiment, the far detector data are compared to a prediction of the emitted neutrino flux to estimate θ 13 . In this thesis, the Double Chooz experiment and its analysis are presented, especially the background studies and the rejection of parasitic signals due to light emitted by photo-multipliers. Neutron fluxes between the different detector volumes impact the definition of the fiducial volume of neutrino interactions and the efficiency of detection. Detailed studies of these effects are presented. As part of the Double Chooz experiment, studies were performed to improve the prediction of neutrino flux emitted by reactors. This work revealed a deficit of observed neutrino rates in the short baseline experiments of last decades. This deficit could be explained by an oscillation to a sterile state. The Stereo project aims to observe a typical signature of oscillations: the distortion of neutrino spectra both in energy and baseline. This thesis presents the detector concept and simulations as well as sensitivity studies. Background sources and the foreseen shielding are also discussed. (author) [fr

  5. Study of the prospective usefulness of the detection of antineutrinos to monitor nuclear power plants for non proliferation purpose

    International Nuclear Information System (INIS)

    Cormon, S.

    2012-01-01

    The field of applied neutrino physics has shown new developments in the last decade. Indeed, the antineutrinos (n e ) emitted by a nuclear power plant depend on the composition of the fuel: thus their detection could be exploited for determining the isotopic composition of the reactor fuel. The International Atomic Energy Agency (IAEA) has expressed its interest in the potentialities of this detection as a new safeguard tool and has created an Ad Hoc working group devoted to this study. Our aim is to determine on the one hand, the current sensitivity reached with the n e detection and on the other hand, the sensitivity required to be useful to the IAEA and then we deduce the required performances required for a cubic meter detector. We will first present the physics on which our feasibility study relies: the neutrinos, the b-decay of the fission products (FP) and their conversion into ne spectra. We will then present our simulation tools: we use a package called MCNP Utility for Reactor Evolution (MURE), initially developed by CNRS/IN2P3 labs to study Generation IV reactors. Thanks to MURE coupled with nuclear data bases, we build the ne spectra by summing the FP contributions. The method is the only one that allows the ne spectra calculations associated to future reactors: we will present the predicted spectra for various innovative fuels. We then calculate the emitted ne associated to various concepts of current and future nuclear reactors in order to determine the sensitivity of the ne probe to various diversion scenarios, taking neutronics into account. The reactor studied are Canadian Deuterium, Pebble Bed Reactor and Fast Breeder Reactor. (author)

  6. A PRECISION MEASUREMENT OF THE NEUTRINO MIXING ANGLE THETA (SUB 13) USING REACTOR ANTINEUTRINOS AT DAYA BAY.

    Energy Technology Data Exchange (ETDEWEB)

    KETTELL, S.; ET AL.

    2006-10-16

    This document describes the design of the Daya Bay reactor neutrino experiment. Recent discoveries in neutrino physics have shown that the Standard Model of particle physics is incomplete. The observation of neutrino oscillations has unequivocally demonstrated that the masses of neutrinos are nonzero. The smallness of the neutrino masses (<2 eV) and the two surprisingly large mixing angles measured have thus far provided important clues and constraints to extensions of the Standard Model. The third mixing angle, {delta}{sub 13}, is small and has not yet been determined; the current experimental bound is sin{sup 2} 2{theta}{sub 13} < 0.17 at 90% confidence level (from Chooz) for {Delta}m{sub 31}{sup 2} = 2.5 x 10{sup -3} eV{sup 2}. It is important to measure this angle to provide further insight on how to extend the Standard Model. A precision measurement of sin{sup 2} 2{theta}{sub 13} using nuclear reactors has been recommended by the 2004 APS Multi-divisional Study on the Future of Neutrino Physics as well as a recent Neutrino Scientific Assessment Group (NUSAG) report. We propose to perform a precision measurement of this mixing angle by searching for the disappearance of electron antineutrinos from the nuclear reactor complex in Daya Bay, China. A reactor-based determination of sin{sup 2} 2{theta}{sub 13} will be vital in resolving the neutrino-mass hierarchy and future measurements of CP violation in the lepton sector because this technique cleanly separates {theta}{sub 13} from CP violation and effects of neutrino propagation in the earth. A reactor-based determination of sin{sup 2} 2{theta}{sub 13} will provide important, complementary information to that from long-baseline, accelerator-based experiments. The goal of the Daya Bay experiment is to reach a sensitivity of 0.01 or better in sin{sup 2} 2{theta}{sub 13} at 90% confidence level.

  7. Measurement of the muon antineutrino double-differential cross section for quasielastic-like scattering on hydrocarbon at Eν˜3.5 GeV

    Science.gov (United States)

    Patrick, C. E.; Aliaga, L.; Bashyal, A.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Budd, H.; Caceres v., G. F. R.; Carneiro, M. F.; Chavarria, E.; da Motta, H.; Dytman, S. A.; Díaz, G. A.; Felix, J.; Fields, L.; Fine, R.; Gago, A. M.; Galindo, R.; Gallagher, H.; Ghosh, A.; Gran, R.; Han, J. Y.; Harris, D. A.; Henry, S.; Hurtado, K.; Jena, D.; Kleykamp, J.; Kordosky, M.; Le, T.; Lu, X.-G.; Maher, E.; Manly, S.; Mann, W. A.; Marshall, C. M.; McFarland, K. S.; McGowan, A. M.; Messerly, B.; Miller, J.; Mislivec, A.; Morfín, J. G.; Mousseau, J.; Naples, D.; Nelson, J. K.; Norrick, A.; Nowak, G. M.; Nuruzzaman, Paolone, V.; Perdue, G. N.; Peters, E.; Ramírez, M. A.; Ransome, R. D.; Ray, H.; Ren, L.; Rodrigues, P. A.; Ruterbories, D.; Schellman, H.; Solano Salinas, C. J.; Sultana, M.; Sánchez Falero, S.; Teklu, A. M.; Valencia, E.; Wolcott, J.; Wospakrik, M.; Yaeggy, B.; Zhang, D.; Miner ν A Collaboration

    2018-03-01

    We present double-differential measurements of antineutrino charged-current quasielastic scattering in the MINERvA detector. This study improves on a previous single-differential measurement by using updated reconstruction algorithms and interaction models and provides a complete description of observed muon kinematics in the form of a double-differential cross section with respect to muon transverse and longitudinal momentum. We include in our signal definition zero-meson final states arising from multinucleon interactions and from resonant pion production followed by pion absorption in the primary nucleus. We find that model agreement is considerably improved by a model tuned to MINERvA inclusive neutrino scattering data that incorporates nuclear effects such as weak nuclear screening and two-particle, two-hole enhancements.

  8. A new measurement of the ratio of the cross sections of muon-neutrino and muon-antineutrino scattering on electrons

    International Nuclear Information System (INIS)

    Bergsma, F.; Dorenbosch, J.; Allaby, J.V.; Amaldi, U.; Barbiellini, G.; Baubillier, M.; Busi, C.; Flegel, W.; Grancagnolo, F.; Lanceri, L.; Metcalf, M.; Nieuwenhuis, C.; Panman, J.; Plunkett, R.; Santoni, C.; Winter, K.; Abt, I.; Aspiazu, J.; Buesser, F.W.; Daumann, H.; Gall, P.D.; Hebbeker, T.; Niebergall, F.; Schuett, P.; Staehelin, P.; Barone, L.; Borgia, B.; Capone, A.; Diemoz, M.; Dore, U.; Ferroni, F.; Longo, E.; Luminari, L.; Monacelli, P.; Notaristefani, F. de; Rome Univ.; Morganti, S.; Valente, V.

    1984-01-01

    A new experimental determination of the electro-weak mixing angle thetasub(W) is reported based on a second exposure of the CHARM calorimeter to the CERN-SPS wide-band beam. The ratio R of muon-neutrino- and muon-antineutrino-electron scattering cross sections has been determined from a sample of 37+-10 and 35+-10 events. The experimental result is R=1.26 (+0.72-0.45), corresponding to a value of sin 2 thetasub(W)=0.216+-0.055. The total sample of events collected in the CHARM calorimeter during the two exposures is (83+-16)νsub(μ)e events and (112+-21)anti νsub(μ)e events, leading to the final result sin 2 thetasub(W)=0.215+-0.032. The systematic error is estimated to be +-0.012. (orig.)

  9. Measurement of the neutral to charged current cross section ratios in neutrino and antineutrino nucleon interactions and determination of the Weinberg angle

    International Nuclear Information System (INIS)

    Abramowicz, H.; Groot, J.G.H. de; Hansl-Kozanecka, T.; Knobloch, J.; May, J.; Navarria, F.L.; Palazzi, P.; Para, A.; Ranjard, F.; Rothberg, J.; Schlatter, D.; Steinberger, J.; Taureg, H.; Rueden, W. von; Wahl, H.; Wotschak, J.; Duda, J.; Eisele, F.; Klasen, H.P.; Kleinknecht, K.; Lierl, H.; Pollmann, D.; Pszola, B.; Renk, B.; Willutzki, H.J.; Dydak, F.; Flottmann, T.; Geweniger, C.; Hepp, V.; Krolikowski, J.; Tittel, K.; Bloch, P.; Bloch-Devaux, B.; Guyot, C.; Loucatos, S.; Maillard, J.; Merlo, J.P.; Peyaud, B.; Rander, J.; Savoy-Navarro, A.; Turlay, R.; He, J.T.; Ruan, T.Z.; Wu, W.M.

    1985-01-01

    The cross section ratios of neutral and charged current interactions induced by neutrinos and antineutrinos in iron have been measured in the 200 GeV narrow-band beam at the CERN SPS. We find Rsub(ν)=0.301+-0.007 and Rsub(anti ν)=0.363+-0.015 for a hadron energy cut of 10 GeV. The results are in agreement with the standard model of electroweak interactions. In the MS renormalization scheme at the scale of the W boson mass sin 2 Osub(w)(msub(w))=0.226+-0.012 is obtained, where the error represents the experimental uncertainty. The theoretical uncertainty is estimated to be Δ sind 2 Osub(w)=+-0.006. (orig.)

  10. Reaction Automata

    OpenAIRE

    Okubo, Fumiya; Kobayashi, Satoshi; Yokomori, Takashi

    2011-01-01

    Reaction systems are a formal model that has been introduced to investigate the interactive behaviors of biochemical reactions. Based on the formal framework of reaction systems, we propose new computing models called reaction automata that feature (string) language acceptors with multiset manipulation as a computing mechanism, and show that reaction automata are computationally Turing universal. Further, some subclasses of reaction automata with space complexity are investigated and their la...

  11. CeLAND: search for a 4th light neutrino state with a 3 PBq 144Ce-144Pr electron antineutrino generator in KamLAND

    Energy Technology Data Exchange (ETDEWEB)

    Gando, A; Gando, Y; Hayashida, S; Ikeda, H; Inoue, K; Ishidoshiro, K; Ishikawa, H; Koga, M; Matsuda, R; Matsuda, S; Mitsui, T; Motoki, D; Nakamura, K; Oki, Y; Otani, M; Shimizu, I; Shirai, J; Suekane, F; Suzuki, A; Takemoto, Y; Tamae, K; Ueshima, K; Watanabe, H; Xu, BD; Yamada, S; Yamauchi, Y; Yoshida, H; Cribier, M; Durero, M; Fischer, V; Gaffiot, J; Jonqueres, N; Kouchner, A; Lasserre, T; Leterme, D; Letourneau, A; Lhuillier, D; Mention, G; Rampal, G; Scola, L; Veyssiere, C; Vivier, M; Yala, P; Berger, BE; Kozlov, A; Banks, T; Dwyer, D; Fujikawa, BK; Han, K; Kolomensky, YG; Mei, Y; O' Donnell, T; Decowski, P; Markoff, DM; Yoshida, S; Kornoukhov, VN; Gelis, TVM; Tikhomirov, GV; Learned, JG; Maricic, J; Matsuno, S; Milincic, R; Karwowski, HJ; Efremenko, Y; Detwiler, A; Enomoto, S

    2017-05-12

    The reactor neutrino and gallium anomalies can be tested with a 3-4 PBq (75-100 kCi scale) 144Ce-144Pr antineutrino beta-source deployed at the center or next to a large low-background liquid scintillator detector. The antineutrino generator will be produced by the Russian reprocessing plant PA Mayak as early as 2014, transported to Japan, and deployed in the Kamioka Liquid Scintillator Anti-Neutrino Detector (KamLAND) as early as 2015. KamLAND's 13 m diameter target volume provides a suitable environment to measure the energy and position dependence of the detected neutrino flux. A characteristic oscillation pattern would be visible for a baseline of about 10 m or less, providing a very clean signal of neutrino disappearance into a yet-unknown, sterile neutrino state. This will provide a comprehensive test of the electron dissaperance neutrino anomalies and could lead to the discovery of a 4th neutrino state for Δm$2\\atop{new}$ ≳ 0.1 eV2 and sin2(2θnew) > 0.05.

  12. The electron antineutrino angular correlation coefficient a in free neutron decay. Testing the standard model with the aSPECT-spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Borg, Michael

    2011-02-04

    The {beta}-decay of free neutrons is a strongly over-determined process in the Standard Model (SM) of Particle Physics and is described by a multitude of observables. Some of those observables are sensitive to physics beyond the SM. For example, the correlation coefficients of the involved particles belong to them. The spectrometer aSPECT was designed to measure precisely the shape of the proton energy spectrum and to extract from it the electron anti-neutrino angular correlation coefficient a. A first test period (2005/2006) showed the ''proof-of-principles''. The limiting influence of uncontrollable background conditions in the spectrometer made it impossible to extract a reliable value for the coefficient a (published in 2008). A second measurement cycle (2007/2008) aimed to under-run the relative accuracy of previous experiments ({delta}a)/(a)=5%. I performed the analysis of the data taken there which is the emphasis of this doctoral thesis. A central point are background studies. The systematic impact of background on a was reduced to ({delta}a{sup (syst.)})/(a)=0.61 %. The statistical accuracy of the analyzed measurements is ({delta}a{sup (stat.)})/(a){approx}1.4 %. Besides, saturation effects of the detector electronics were investigated which were initially observed. These turned out not to be correctable on a sufficient level. An applicable idea how to avoid the saturation effects is discussed in the last chapter. (orig.)

  13. The electron antineutrino angular correlation coefficient a in free neutron decay. Testing the standard model with the aSPECT-spectrometer

    International Nuclear Information System (INIS)

    Borg, Michael

    2011-01-01

    The β-decay of free neutrons is a strongly over-determined process in the Standard Model (SM) of Particle Physics and is described by a multitude of observables. Some of those observables are sensitive to physics beyond the SM. For example, the correlation coefficients of the involved particles belong to them. The spectrometer aSPECT was designed to measure precisely the shape of the proton energy spectrum and to extract from it the electron anti-neutrino angular correlation coefficient a. A first test period (2005/2006) showed the ''proof-of-principles''. The limiting influence of uncontrollable background conditions in the spectrometer made it impossible to extract a reliable value for the coefficient a (published in 2008). A second measurement cycle (2007/2008) aimed to under-run the relative accuracy of previous experiments (δa)/(a)=5%. I performed the analysis of the data taken there which is the emphasis of this doctoral thesis. A central point are background studies. The systematic impact of background on a was reduced to (δa (syst.) )/(a)=0.61 %. The statistical accuracy of the analyzed measurements is (δa (stat.) )/(a)∼1.4 %. Besides, saturation effects of the detector electronics were investigated which were initially observed. These turned out not to be correctable on a sufficient level. An applicable idea how to avoid the saturation effects is discussed in the last chapter. (orig.)

  14. Neutrino reactions in hot and dense matter

    International Nuclear Information System (INIS)

    Lohs, Andreas

    2015-01-01

    In this thesis, neutrino reactions in hot and dense matter are studied. In particular, this work is concerned with neutrino-matter interactions that are relevant for neutrino transport in core-collapse supernovae (CCSNe). The majority of the energy from a CCSN is released in the form of neutrinos. Accurate understanding and computation of these interactions is most relevant to achieve sufficiently reliable predictions for the evolution of CCSNe and other related question such as the production of heavy elements or neutrino oscillations. For this purpose this work follows the combined approach of searching for new important neutrino reactions and improving the computation of those reactions that are already implemented. First we estimate the relevance of charged-current weak interactions that include muon-neutrinos or muons, as well as the role of neutron decay for neutrino transport in CCSNe. All of these reactions were previously neglected in CCSN-simulations. We derive and compute the matrix element and subsequent semi-analytic expressions for transport properties like the inverse mean free path of the new reactions. It is found that these reactions are important for muon neutrinos and low energy electron antineutrinos at very high densities in the protoneutron star surface. Consequently their implementation might lead to several changes in the prediction of CCSNe signatures such as the nucleosynthesis yields. Second we improve the precision in the computation of well known neutrino-nucleon reactions like neutrino absorption on neutrons. We derive semi-analytic expressions for transport properties that use less restrictive approximations while keeping the computational demand constant. Therefore we consider the full relativistic kinematics of all participating particles i.e. allowing for relativistic nucleons and finite lepton masses. Also the weak magnetism terms of the matrix elements are explicitly included to all orders. From our results we suggest that the

  15. Neutrino reactions in hot and dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Lohs, Andreas

    2015-04-13

    In this thesis, neutrino reactions in hot and dense matter are studied. In particular, this work is concerned with neutrino-matter interactions that are relevant for neutrino transport in core-collapse supernovae (CCSNe). The majority of the energy from a CCSN is released in the form of neutrinos. Accurate understanding and computation of these interactions is most relevant to achieve sufficiently reliable predictions for the evolution of CCSNe and other related question such as the production of heavy elements or neutrino oscillations. For this purpose this work follows the combined approach of searching for new important neutrino reactions and improving the computation of those reactions that are already implemented. First we estimate the relevance of charged-current weak interactions that include muon-neutrinos or muons, as well as the role of neutron decay for neutrino transport in CCSNe. All of these reactions were previously neglected in CCSN-simulations. We derive and compute the matrix element and subsequent semi-analytic expressions for transport properties like the inverse mean free path of the new reactions. It is found that these reactions are important for muon neutrinos and low energy electron antineutrinos at very high densities in the protoneutron star surface. Consequently their implementation might lead to several changes in the prediction of CCSNe signatures such as the nucleosynthesis yields. Second we improve the precision in the computation of well known neutrino-nucleon reactions like neutrino absorption on neutrons. We derive semi-analytic expressions for transport properties that use less restrictive approximations while keeping the computational demand constant. Therefore we consider the full relativistic kinematics of all participating particles i.e. allowing for relativistic nucleons and finite lepton masses. Also the weak magnetism terms of the matrix elements are explicitly included to all orders. From our results we suggest that the

  16. Nuclear reactions

    International Nuclear Information System (INIS)

    Lane, A.M.

    1980-01-01

    In reviewing work at Harwell over the past 25 years on nuclear reactions it is stated that a balance has to be struck in both experiment and theory between work on cross-sections of direct practical relevance to reactors and on those relevant to an overall understanding of reaction processes. The compound nucleus and direct process reactions are described. Having listed the contributions from AERE, Harwell to developments in nuclear reaction research in the period, work on the optical model, neutron capture theory, reactions at doorway states with fine structure, and sum-rules for spectroscopic factors are considered in more detail. (UK)

  17. Reaction mechanisms

    International Nuclear Information System (INIS)

    Nguyen Trong Anh

    1988-01-01

    The 1988 progress report of the Reaction Mechanisms laboratory (Polytechnic School, France), is presented. The research topics are: the valence bond methods, the radical chemistry, the modelling of the transition states by applying geometric constraints, the long range interactions (ion - molecule) in gaseous phase, the reaction sites in gaseous phase and the mass spectroscopy applications. The points of convergence between the investigations of the mass spectroscopy and the theoretical chemistry teams, as well as the purposes guiding the research programs, are discussed. The published papers, the conferences, the congress communications and the thesis, are also reported [fr

  18. Capture reactions

    NARCIS (Netherlands)

    Endt, P.M.

    1956-01-01

    Capture reactions will be considered here from the viewpoint of the nuclear spectroscopist. Especially important to him are the capture of neutrons, protons, and alpha particles, which may proceed through narrow resonances, offering a well defined initial state for the subsequent deexcitation

  19. Allergic reactions

    Science.gov (United States)

    ... that don't bother most people (such as venom from bee stings and certain foods, medicines, and pollens) can ... person. If the allergic reaction is from a bee sting, scrape the ... more venom. If the person has emergency allergy medicine on ...

  20. cycloaddition reactions

    Indian Academy of Sciences (India)

    Unknown

    ... has shown very severe limitations in predicting the regioselectivity. In comparison,. DFT-based descriptors are better suited to model the regioselectivity of cycloaddition reactions. Acknowledgements. GG thanks the Council of Scientific and Industrial. Research for a fellowship. References. 1. Winkler J D 1996 Chem. Rev.

  1. Review of Reactor Antineutrino Experiments

    OpenAIRE

    Djurcic, Zelimir

    2012-01-01

    As discussed elsewhere, the measurement of a non-zero value for $\\theta_{13}$ would open up a wide range of possibilities to explore CP-violation and the mass hierarchy. Experimental methods to measure currently the unknown mixing angle $\\theta_{13}$ include accelerator searches for the $\

  2. Spallation reactions

    International Nuclear Information System (INIS)

    Cugon, J.

    1996-01-01

    Spallation reactions dominate the interactions of hadrons with nuclei in the GeV range (from ∼ 0.1 to ∼ 10 GeV). They correspond to a sometimes important ejection of light particles leaving most of the time a residue of mass commensurate with the target mass. The main features of the experimental data are briefly reviewed. The most successful theoretical model, namely the intranuclear cascade + evaporation model, is presented. Its physical content, results and possible improvements are critically discussed. Alternative approaches are shortly reviewed. (author)

  3. Nuclear reactions

    International Nuclear Information System (INIS)

    Corner, J.; Richardson, K.; Fenton, N.

    1990-01-01

    Nuclear reactions' marks a new development in the study of television as an agency of public policy debate. During the Eighties, nuclear energy became a major international issue. The disasters at Three-mile Island and Chernobyl created a global anxiety about its risks and a new sensitivity to it among politicians and journalists. This book is a case-study into documentary depictions of nuclear energy in television and video programmes and into the interpretations and responses of viewers drawn from many different occupational groupings. How are the complex and specialist arguments about benefit, risk and proof conveyed through the different conventions of commentary, interview and film sequence? What symbolic associations does the visual language of television bring to portrayals of the issue? And how do viewers make sense of various and conflicting accounts, connecting what they see and hear on the screen with their pre-existing knowledge, experience and 'civic' expectations. The authors examine some of the contrasting forms and themes which have been used by programme makers to explain and persuade, and then give a sustained analysis of the nature and sources of viewers' own accounts. 'Nuclear Reactions' inquires into the public meanings surrounding energy and the environment, spelling out in its conclusion some of the implications for future media treatments of this issue. It is also a key contribution to the international literature on 'television knowledge' and the processes of active viewing. (author)

  4. Chain reaction

    International Nuclear Information System (INIS)

    Balogh, Brian.

    1991-01-01

    Chain Reaction is a work of recent American political history. It seeks to explain how and why America came to depend so heavily on its experts after World War II, how those experts translated that authority into political clout, and why that authority and political discretion declined in the 1970s. The author's research into the internal memoranda of the Atomic Energy Commission substantiates his argument in historical detail. It was not the ravages of American anti-intellectualism, as so many scholars have argued, that brought the experts back down to earth. Rather, their decline can be traced to the very roots of their success after World War II. The need to over-state anticipated results in order to garner public support, incessant professional and bureaucratic specialization, and the sheer proliferation of expertise pushed arcane and insulated debates between experts into public forums at the same time that a broad cross section of political participants found it easier to gain access to their own expertise. These tendencies ultimately undermined the political influence of all experts. (author)

  5. Evolved Models for Elementary Particles and Atoms Require Alternating Neutrino/Antineutrino Pairs Along Interlocked or Looped Strings. Traveling Waves, TW, and Standing Waves, SW, Alternate at Nodal Notches

    Science.gov (United States)

    McLeod, Roger David; McLeod, David Matthew

    2009-05-01

    Our hydrogen atom interacts with a neutron star. Its stringy TW/SW electron is cut by a neutrino scissor that instantly becomes its end anti-node. The string has one extra neutrino in 100,000. Antimatter remains concealed. Our Dumbo Proton of a TW state is similarly cut. Inside the star, electron string/spring compresses 100,000 and 1836 times more, to proton's linear mass density. Electrostatics encourages that caboose, stringy electron, to couple with a cut proton. Linear charge densities neutralize while composite length contracts 20%. The writhing string evicts an antineutrino at closure on Pauli's authority, becoming Mickey Neutron, with looped quarks. Unstable Mickey Neutron has his ear notch forced into an ear notch of stable Dumbo Proton, achieving immortality in this deuteron marriage. Tritium is in a m'enage a trois. Alpha Nucleus has a # grid. Meta state Ne-20 predicts alpha eviction to O-16. Schr"odinger finally prevails, so string theory and Wave Mechanics can prosper.

  6. Catalysis of Photochemical Reactions.

    Science.gov (United States)

    Albini, A.

    1986-01-01

    Offers a classification system of catalytic effects in photochemical reactions, contrasting characteristic properties of photochemical and thermal reactions. Discusses catalysis and sensitization, examples of catalyzed reactions of excepted states, complexing ground state substrates, and catalysis of primary photoproducts. (JM)

  7. On Thermonuclear Reaction Rates

    OpenAIRE

    Haubold, H. J.; Mathai, A. M.

    1996-01-01

    Nuclear reactions govern major aspects of the chemical evolution of galaxies and stars. Analytic study of the reaction rates and reaction probability integrals is attempted here. Exact expressions for the reaction rates and reaction probability integrals for nuclear reactions in the cases of nonresonant, modified nonresonant, screened nonresonant and resonant cases are given. These are expressed in terms of H-functions, G-functions and in computable series forms. Computational aspects are als...

  8. [Adverse reactions to insulin].

    Science.gov (United States)

    Liñana, J J; Montoro, F J; Hernández, M D; Basomba, A

    1997-07-01

    The prevalence of allergic reactions to insuline has decreased during the last few years. Probably this is due to the use of the newly-developed recombinant human insuline. At present, adverse reactions to insuline occur in 5-10% of patients on therapy with insuline. Adverse reactions may be local (more frequent) or systemic (rare). Insuline resistance consists in a different type of immunological reaction. Diagnosis of allergy to insuline is based on clinical history and cutaneous and serological tests. Treatment depends upon the severity of the reaction. When insuline is indispensable despite a previous allergic reaction, a desensitization protocol may be implemented.

  9. Preequilibrium Nuclear Reactions

    International Nuclear Information System (INIS)

    Strohmaier, B.

    1988-01-01

    After a survey on existing experimental data on precompound reactions and a description of preequilibrium reactions, theoretical models and quantum mechanical theories of preequilibrium emission are presented. The 25 papers of this meeting are analyzed separately

  10. Microfluidic chemical reaction circuits

    Science.gov (United States)

    Lee, Chung-cheng [Irvine, CA; Sui, Guodong [Los Angeles, CA; Elizarov, Arkadij [Valley Village, CA; Kolb, Hartmuth C [Playa del Rey, CA; Huang, Jiang [San Jose, CA; Heath, James R [South Pasadena, CA; Phelps, Michael E [Los Angeles, CA; Quake, Stephen R [Stanford, CA; Tseng, Hsian-rong [Los Angeles, CA; Wyatt, Paul [Tipperary, IE; Daridon, Antoine [Mont-Sur-Rolle, CH

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  11. Oral Hypersensitivity Reactions

    Science.gov (United States)

    ... such as cinnamon, peppermint, eugenol and menthol. Even dental floss and denture cleansers may contain ingredients known to cause a hypersensitivity reaction. Q: How can dental treatment trigger a hypersensitivity reaction? A: Some dental ...

  12. Chemical transport reactions

    CERN Document Server

    Schäfer, Harald

    2013-01-01

    Chemical Transport Reactions focuses on the processes and reactions involved in the transport of solid or liquid substances to form vapor phase reaction products. The publication first offers information on experimental and theoretical principles and the transport of solid substances and its special applications. Discussions focus on calculation of the transport effect of heterogeneous equilibria for a gas motion between equilibrium spaces; transport effect and the thermodynamic quantities of the transport reaction; separation and purification of substances by means of material transport; and

  13. Thermonuclear reaction rates. III

    International Nuclear Information System (INIS)

    Harris, M.J.; Fowler, W.A.; Caughlan, G.R.; Zimmerman, B.A.

    1983-01-01

    Stellar thermonuclear reaction rates are revised and updated, adding a number of new important reaction rates. Several reactions with large negative Q-values are included, and examples of them are discussed. The importance of the decay rates for Mg-26(p,n) exp 26 Al and Al-26(n,p) exp 26 Mg for stellar studies is emphasized. 19 references

  14. Cluster knockout reactions

    Indian Academy of Sciences (India)

    2014-04-07

    Apr 7, 2014 ... advancements in the area of (α, 2α) reactions and heavy cluster knockout reactions are discussed. Importance of the finite-range vertex and the final-state interactions are brought out. Keywords. Cluster knockout reactions; FR-DWIA calculations; t-matrix effective interaction. PACS Nos 14.20.Pt; 24.10.

  15. ORGANIC REACTION MECHANISM CONTROVERSY ...

    African Journals Online (AJOL)

    Preferred Customer

    However, there are so many chemical reactions notably in organic chemistry where reactions may not directly lead to products. ... There are concepts that support these ideas but can they be proven to the ... Reaction mechanism is one such issue in organic chemistry that has attracted a lot of controversial comments from ...

  16. Maillard Reaction: review

    Directory of Open Access Journals (Sweden)

    Júlia d'Almeida Francisquini

    2017-11-01

    Full Text Available Maillard reaction is an important subject of study in food science and technology and different areas of knowledge are involved such as chemistry, food engineering, nutrition and food technology. The objective of this paper is to present the basic concepts of the Maillard reaction, such as the reaction stages, the main compounds producced and some technological consequences for dairy products.

  17. Resonant thermonuclear reaction rate

    International Nuclear Information System (INIS)

    Haubold, H.J.; Mathai, A.M.

    1986-01-01

    Basic physical principles for the resonant and nonresonant thermonuclear reaction rates are applied to find their standard representations for nuclear astrophysics. Closed-form representations for the resonant reaction rate are derived in terms of Meijer's G-function. Analytic representations of the resonant and nonresonant nuclear reaction rates are compared and the appearance of Meijer's G-function is discussed in physical terms

  18. Nuclear reaction studies

    International Nuclear Information System (INIS)

    Alexander, J.M.; Lacey, R.A.

    1994-01-01

    Research focused on the statistical and dynamical properties of ''hot'' nuclei formed in symmetric heavy-ion reactions. Theses included ''flow'' measurements and the mechanism for multifragment disassembly. Model calculations are being performed for the reactions C+C, Ne+Al, Ar+Sc, Kr+Nb, and Xe+La. It is planned to study 40 Ar reactions from 27 to 115 MeV/nucleon. 2 figs., 41 refs

  19. Sleeve reaction chamber system

    Science.gov (United States)

    Northrup, M Allen [Berkeley, CA; Beeman, Barton V [San Mateo, CA; Benett, William J [Livermore, CA; Hadley, Dean R [Manteca, CA; Landre, Phoebe [Livermore, CA; Lehew, Stacy L [Livermore, CA; Krulevitch, Peter A [Pleasanton, CA

    2009-08-25

    A chemical reaction chamber system that combines devices such as doped polysilicon for heating, bulk silicon for convective cooling, and thermoelectric (TE) coolers to augment the heating and cooling rates of the reaction chamber or chambers. In addition the system includes non-silicon-based reaction chambers such as any high thermal conductivity material used in combination with a thermoelectric cooling mechanism (i.e., Peltier device). The heat contained in the thermally conductive part of the system can be used/reused to heat the device, thereby conserving energy and expediting the heating/cooling rates. The system combines a micromachined silicon reaction chamber, for example, with an additional module/device for augmented heating/cooling using the Peltier effect. This additional module is particularly useful in extreme environments (very hot or extremely cold) where augmented heating/cooling would be useful to speed up the thermal cycling rates. The chemical reaction chamber system has various applications for synthesis or processing of organic, inorganic, or biochemical reactions, including the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction.

  20. Sodium-concrete reactions

    International Nuclear Information System (INIS)

    Gadd, P.G.

    1982-09-01

    Reaction products of all the major constituents of commercial concrete with liquid sodium have been identified using X-Ray Powder Diffraction. Eight different aggregate materials were chosen to represent the main rock classes available and Ordinary Portland Cement was used throughout. A Differential Thermal Analysis apparatus which enabled continuous stirring of the reactants was designed to improve contact between the powdered concrete components and the liquid sodium. Heats of reaction were calculated from peak areas, the apparatus having been calibrated using reactions of sodium with simple binary oxides whose heats of reaction were known. The heat evolution from aggregates was rationalised on the basis of their mineralogical composition, thus providing a means of choosing an optimum aggregate for use in the concrete of a LMFBR. The reaction of SiO 2 with liquid sodium was shown to depend on the oxygen concentration of the sodium. Reaction products are identified. The reaction of Al 2 O 3 with sodium has been shown also to depend on the oxygen concentration. Reaction products are identified. The evolution of hydrogen during a sodium-cement reaction has been studied using an electrochemical hydrogen meter and the penetration of the liquid metal into cement blocks was also investigated. (author)

  1. Tattoo reaction: Case series

    Directory of Open Access Journals (Sweden)

    Muneer Mohamed

    2018-04-01

    Full Text Available Tattoo is going to be a very common practice especially among young people and we are witnessing a gradual increase of numerous potential complications to tattoo placement which are often seen by physicians, but generally unknown to the public. The most common skin reactions to tattoo include a transient acute inflammatory reaction due to trauma of the skin with needles and medical complications such as superficial and deep local infections, systemic infections, allergic contact dermatitis, photodermatitis, granulomatous and lichenoid reactions, and skin diseases localized on tattooed area (eczema, psoriasis, lichen, and morphea. In this series we present three cases of tattoo reaction.

  2. Clock Reaction: Outreach Attraction

    Science.gov (United States)

    Carpenter, Yuen-ying; Phillips, Heather A.; Jakubinek, Michael B.

    2010-01-01

    Chemistry students are often introduced to the concept of reaction rates through demonstrations or laboratory activities involving the well-known iodine clock reaction. For example, a laboratory experiment involving thiosulfate as an iodine scavenger is part of the first-year general chemistry laboratory curriculum at Dalhousie University. With…

  3. Nuclear Reaction Data Centers

    International Nuclear Information System (INIS)

    McLane, V.; Nordborg, C.; Lemmel, H.D.; Manokhin, V.N.

    1988-01-01

    The cooperating Nuclear Reaction Data Centers are involved in the compilation and exchange of nuclear reaction data for incident neutrons, charged particles and photons. Individual centers may also have services in other areas, e.g., evaluated data, nuclear structure and decay data, reactor physics, nuclear safety; some of this information may also be exchanged between interested centers. 20 refs., 1 tab

  4. Hydrogen evolution reaction catalyst

    Science.gov (United States)

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  5. Applications of Reaction Rate

    Science.gov (United States)

    Cunningham, Kevin

    2007-01-01

    This article presents an assignment in which students are to research and report on a chemical reaction whose increased or decreased rate is of practical importance. Specifically, students are asked to represent the reaction they have chosen with an acceptable chemical equation, identify a factor that influences its rate and explain how and why it…

  6. Degradations and Rearrangement Reactions

    Science.gov (United States)

    Zhang, Jianbo

    This section deals with recent reports concerning degradation and rearrangement reactions of free sugars as well as some glycosides. The transformations are classified in chemical and enzymatic ways. In addition, the Maillard reaction will be discussed as an example of degradation and rearrangement transformation and its application in current research in the fields of chemistry and biology.

  7. Allergic reactions during anesthesia.

    Science.gov (United States)

    Levy, J H

    1988-01-01

    Any drug or blood product administered in the perioperative period has the potential to produce a life-threatening allergic (immune reaction) called anaphylaxis. Anaphylactic reactions represent adverse reactions mediated by immunospecific antibodies (IgE and IgG) that interact with mast cells, basophils, or the complement system to liberate vasoactive mediators and recruit other inflammatory cells. Activation of humoral and cellular pathways produces characteristic responses in the respiratory (bronchospasm and upper airway edema), cardiovascular (vasodilation and increased capillary permeability), and cutaneous systems (wheal and flare). Other predictable adverse drug reactions may mimic anaphylaxis to produce similar physiologic consequences independent of allergy (immune responses). Rapid and timely cardiopulmonary intervention with airway maintenance, epinephrine, and volume expansion is essential to avoid an adverse outcome. Severe reactions may be protracted, especially during anesthesia, requiring even larger doses of catecholamines and intensive care observation.

  8. Enhancing chemical reactions

    Science.gov (United States)

    Morrey, John R.

    1978-01-01

    Methods of enhancing selected chemical reactions. The population of a selected high vibrational energy state of a reactant molecule is increased substantially above its population at thermal equilibrium by directing onto the molecule a beam of radiant energy from a laser having a combination of frequency and intensity selected to pump the selected energy state, and the reaction is carried out with the temperature, pressure, and concentrations of reactants maintained at a combination of values selected to optimize the reaction in preference to thermal degradation by transforming the absorbed energy into translational motion. The reaction temperature is selected to optimize the reaction. Typically a laser and a frequency doubler emit radiant energy at frequencies of .nu. and 2.nu. into an optical dye within an optical cavity capable of being tuned to a wanted frequency .delta. or a parametric oscillator comprising a non-centrosymmetric crystal having two indices of refraction, to emit radiant energy at the frequencies of .nu., 2.nu., and .delta. (and, with a parametric oscillator, also at 2.nu.-.delta.). Each unwanted frequency is filtered out, and each desired frequency is focused to the desired radiation flux within a reaction chamber and is reflected repeatedly through the chamber while reactants are fed into the chamber and reaction products are removed therefrom.

  9. Respiratory transfusion reactions

    Directory of Open Access Journals (Sweden)

    Ivica Marić

    2017-11-01

    Full Text Available Respiratory transfusion-related reactions are not very frequent, partly also because recognition and reporting transfusion reactions is still underemphasized. Tis article describes the most important respiratory transfusion reactions, their pathophysiology, clinical picture and treatment strategies. Respiratory transfusion related reactions can be primary or secondary. The most important primary transfusion-related reactions are TRALI - transfusion-related acute lung injury, TACO – transfusion-associated circulatory overload, and TAD - transfusion-associated dyspnea. TRALI is immuneassociated injury of alveolar basal membrane, which becomes highly permeable and causes noncardiogenic pulmonary edema. Treatment of TRALI is mainly supportive with oxygen, fluids (in case of hypotension and in cases of severe acute respiratory failure also mechanic ventilation. TACO is caused by volume overload in predisposed individuals, such as patients with heart failure, the elderly, infants, patients with anemia and patients with positive fluid balance. Clinical picture is that of a typical pulmonary cardiogenic edema, and the therapy is classical: oxygen and diuretics, and in severe cases also non-invasive or invasive mechanical ventilation. TAD is usually a mild reaction of unknown cause and cannot be classified as TACO or TRALI, nor can it be ascribed to patient’s preexisting diseases. Although the transfusion-related reactions are not very common, knowledge about them can prevent serious consequences. On the one hand preventive measures should be sought, and on the other early recognition is beneficial, so that proper treatment can take place.

  10. The Reaction Wheel Pendulum

    CERN Document Server

    Block, Daniel J; Spong, Mark W

    2007-01-01

    This monograph describes the Reaction Wheel Pendulum, the newest inverted-pendulum-like device for control education and research. We discuss the history and background of the reaction wheel pendulum and other similar experimental devices. We develop mathematical models of the reaction wheel pendulum in depth, including linear and nonlinear models, and models of the sensors and actuators that are used for feedback control. We treat various aspects of the control problem, from linear control of themotor, to stabilization of the pendulum about an equilibrium configuration using linear control, t

  11. Electron transfer reactions

    CERN Document Server

    Cannon, R D

    2013-01-01

    Electron Transfer Reactions deals with the mechanisms of electron transfer reactions between metal ions in solution, as well as the electron exchange between atoms or molecules in either the gaseous or solid state. The book is divided into three parts. Part 1 covers the electron transfer between atoms and molecules in the gas state. Part 2 tackles the reaction paths of oxidation states and binuclear intermediates, as well as the mechanisms of electron transfer. Part 3 discusses the theories and models of the electron transfer process; theories and experiments involving bridged electron transfe

  12. Reactor for exothermic reactions

    Science.gov (United States)

    Smith, L.A. Jr.; Hearn, D.; Jones, E.M. Jr.

    1993-03-02

    A liquid phase process is described for oligomerization of C[sub 4] and C[sub 5] isoolefins or the etherification thereof with C[sub 1] to C[sub 6] alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300 F. Wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

  13. Bad Reaction to Cosmetics?

    Science.gov (United States)

    ... Consumers Protect Yourself Health Fraud Bad Reactions to Cosmetics? Tell FDA! Share Tweet Linkedin Pin it More ... Radiation-Emitting Products Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products

  14. Transfusion reaction - hemolytic

    Science.gov (United States)

    ... Names Blood transfusion reaction Images Surface proteins causing rejection References Choate JD, Maitta RW, Tormey CA, Wu ... PA: Elsevier Saunders; 2016:chap 177. Hall JE. Blood types; transfusion; tissue and organ transplantation. In: Hall JE, ...

  15. Reaction Qualifications Revisited

    DEFF Research Database (Denmark)

    Lippert-Rasmussen, Kasper

    2009-01-01

    to a person's effectiveness by causing a favourable reaction in customers, co-workers etc. (for short: recipients) - are involved, this assumption is false. Building on work by Wertheimer, Mason, and Miller, this paper proposes an account of the reaction qualifications that count, from the point of view...... preferences, recipients should not respond to the applicant actually hired on the basis of their (the recipients') racial preferences. My account decomposes the meritocratic ideal into four separate norms, one of which applies to recipients rather than to selectors. Finally, it defends the view that reaction...... qualifications based on antimeritocratic reactions, while not unproblematic, are not entirely irrelevant from the point of view of merit. Notably, selectors need not discount them when no one - including the targets of the objectionable preferences - is unfairly disadvantaged. Because not all problematic...

  16. Sequential charged particle reaction

    International Nuclear Information System (INIS)

    Hori, Jun-ichi; Ochiai, Kentaro; Sato, Satoshi; Yamauchi, Michinori; Nishitani, Takeo

    2004-01-01

    The effective cross sections for producing the sequential reaction products in F82H, pure vanadium and LiF with respect to the 14.9-MeV neutron were obtained and compared with the estimation ones. Since the sequential reactions depend on the secondary charged particles behavior, the effective cross sections are corresponding to the target nuclei and the material composition. The effective cross sections were also estimated by using the EAF-libraries and compared with the experimental ones. There were large discrepancies between estimated and experimental values. Additionally, we showed the contribution of the sequential reaction on the induced activity and dose rate in the boundary region with water. From the present study, it has been clarified that the sequential reactions are of great importance to evaluate the dose rates around the surface of cooling pipe and the activated corrosion products. (author)

  17. Firefighter Nozzle Reaction

    DEFF Research Database (Denmark)

    Chin, Selena K.; Sunderland, Peter B.; Jomaas, Grunde

    2017-01-01

    to anchor forces, the hose becomes straight. The nozzle reaction is found to equal the jet momentum flow rate, and it does not change when an elbow connects the hose to the nozzle. A forward force must be exerted by a firefighter or another anchor that matches the forward force that the jet would exert...... on a perpendicular wall. Three reaction expressions are derived, allowing it to be determined in terms of hose diameter, jet diameter, flow rate, and static pressure upstream of the nozzle. The nozzle reaction predictions used by the fire service are 56% to 90% of those obtained here for typical firefighting hand......Nozzle reaction and hose tension are analyzed using conservation of fluid momentum and assuming steady, inviscid flow and a flexible hose in frictionless contact with the ground. An expression that is independent of the bend angle is derived for the hose tension. If this tension is exceeded owing...

  18. Nucleon induced reactions

    International Nuclear Information System (INIS)

    Gmuca, S.; Antalik, R.; Kristiak, J.

    1988-01-01

    The collection contains full texts of 37 contributions; all fall within the INIS Subject Scope. The topics treated include some unsolved problems of nuclear reactions and relevant problems of nuclear structure at low and intermediate energies. (Z.S.)

  19. Jets in hadronic reactions

    Energy Technology Data Exchange (ETDEWEB)

    Paige, F.E.

    1983-01-01

    Recent experimental data on the properties of jets in hadronic reactions are reviewed and compared with theoretical expectations. Jets are clearly established as the dominant process for high E/sub T/ events in hadronic reactions. The cross section and the other properties of these events are in qualitative and even semiquantitative agreement with expectations based on perturbative QCD. However, we can not yet make precise tests of QCD, primarily because there are substantial uncertainties in the theoretical calculations. 45 references. (WHK)

  20. Oxygen evolution reaction catalysis

    Science.gov (United States)

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

    2016-09-06

    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  1. Anaphylactic reaction to orthoiodohippurate

    Energy Technology Data Exchange (ETDEWEB)

    Stoeckel, M.; Roedbro, P.; Ennow, K.; Kristensen, K.

    1983-02-01

    A case of an anaphylactic reaction following administration of /sup 125/I- and /sup 131/-I-o-iodohippurate in a 32-year-old woman is reported. The patient had a renography performed because of hematuria. She was known to react to an intravenous pyelography previously performed with an anaphylactic shock. The importance of reporting all adverse reactions to radiopharmaceuticals for central registration is stressed.

  2. Adverse drug reactions.

    Science.gov (United States)

    Patton, K; Borshoff, D C

    2018-01-01

    Adverse drug reactions are a cause of significant morbidity and mortality to patients and a source of financial burden to the healthcare system. Of the wide spectrum of adverse drug reactions, the most concerning to the anaesthetist remain anaphylaxis and malignant hyperthermia. Although the incidence of anaphylaxis under anaesthesia is difficult to ascertain, it occurs commonly enough that most anaesthetists will manage at least one case in their career. The wide range of drugs given in the peri-operative period and the variable presentation in the anaesthetised patient can delay diagnosis and treatment, and adversely affect outcome. Furthermore, despite improvements in testing, causative drugs can still be difficult to identify, as adverse reactions may be mediated by mechanisms other than IgE activation. With an increase in the reporting of anaphylaxis to newer anaesthetic drugs such as sugammadex, combined with change over the recent decades in the most likely causative peri-operative agents, it is imperative anaesthetists remain up to date on recent developments. In addition, they should be vigilant to patient characteristics, including pharmacogenetic variations that may predispose to adverse drug reactions, in order to help minimise risks of a reaction. The severity of adverse drug reactions to peri-operative drugs means morbidity and mortality remain high. © 2018 The Association of Anaesthetists of Great Britain and Ireland.

  3. Immediate reaction to clarithromycin.

    Science.gov (United States)

    Gangemi, S; Ricciardi, L; Fedele, R; Isola, S; Purello-D'Ambrosio, F

    2001-01-01

    We present the case of bronchospastic reaction to clarithromycin had during a drug challenge test. Personal allergic history was negative for respiratory allergies and positive for adverse drug reactions to general and regional anesthesia and to ceftriaxone. After the administration of 1/4 of therapeutic dose of clarithromycin the patient showed dyspnea, cough and bronchospasm in all the lung fields. The positivity of the test was confirmed by the negativity to the administration of placebo. The quickness and the clinical characteristic of the adverse reaction suggest a pathogenic mechanism of immediate-type hypersensitivity. On reviewing the literature we have found no reports of bronchospastic reaction to clarithromycin. Macrolides are a class of antibiotics mainly used in the last years in place of beta-lactams because of a broad spectrum of action and a low allergic power. In fact, there are few reports on allergic reactions to these molecules. Clarithromycin is one of the latest macrolides, characterised by the presence of a 14-carbon-atom lactone ring as erythromycin, active on a wide spectrum of pathogens.

  4. Chemical kinetics of gas reactions

    CERN Document Server

    Kondrat'Ev, V N

    2013-01-01

    Chemical Kinetics of Gas Reactions explores the advances in gas kinetics and thermal, photochemical, electrical discharge, and radiation chemical reactions. This book is composed of 10 chapters, and begins with the presentation of general kinetic rules for simple and complex chemical reactions. The next chapters deal with the experimental methods for evaluating chemical reaction mechanisms and some theories of elementary chemical processes. These topics are followed by discussions on certain class of chemical reactions, including unimolecular, bimolecular, and termolecular reactions. The rema

  5. Inflammatory reaction in chondroblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Yamamura, Sigeki [Dept. of Orthopedic Surgery, Nagoya Univ. School of Medicine (Japan); Sato, Keiji [Dept. of Orthopedic Surgery, Nagoya Univ. School of Medicine (Japan); Sugiura, Hideshi [Dept. of Orthopedic Surgery, Nagoya Univ. School of Medicine (Japan); Iwata, Hisashi [Dept. of Orthopedic Surgery, Nagoya Univ. School of Medicine (Japan)

    1996-05-01

    The objective of this study was to evaluate the inflammatory reaction accompanying chondroblastoma and to define the value of the finding in clinical practice. We reviewed the clinical, radiographic, and magnetic resonance (MR) findings in six patients with histologically proven chondroblastoma. In all cases, MR imaging showered marrow and soft tissue edema. In four of six cases, periosteal reaction related to intra-osseous edema was more clearly demonstrated on MR imaging than on radiographs. Follow-up MR studies after surgery were available in three patients and all showed disappearance of inflammatory responses such as marrow and soft tissue edema, and reactive synovitis. We propose that these inflammatory reactions of chondroblastomas are inportant signs for detecting residual tumor in recurrences after surgery, as well as for making a precise diagnosis. The MR changes may also be valuable in demonstrating eradication of the tumor. (orig./MG)

  6. Nanoparticle Reactions on Chip

    Science.gov (United States)

    Köhler, J. M.; Kirner, Th.; Wagner, J.; Csáki, A.; Möller, R.; Fritzsche, W.

    The handling of heterogenous systems in micro reactors is difficult due to their adhesion and transport behaviour. Therefore, the formation of precipitates and gas bubbles has to be avoided in micro reaction technology, in most cases. But, micro channels and other micro reactors offer interesting possibilities for the control of reaction conditions and transport by diffusion and convection due to the laminar flow caused by small Reynolds numbers. This can be used for the preparation and modification of objects, which are much smaller than the cross section of microchannels. The formation of colloidal solutions and the change of surface states of nano particles are two important tasks for the application of chip reactors in nanoparticle technology. Some concepts for the preparation and reaction of nanoparticles in modular chip reactor arrangements will be discussed.

  7. Velocity pump reaction turbine

    Science.gov (United States)

    House, P.A.

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

  8. Reactions to dietary tartrazine.

    OpenAIRE

    David, T J

    1987-01-01

    Double blind challenges with tartrazine and benzoic acid were performed in hospital in 24 children whose parents gave a definite history of a purely behavioural immediate adverse reaction to one of these substances. The patients, whose ages ranged from 1.6 to 12.4 years, were on a diet that avoided these items, and in all there was a clear history that any lapse of the diet caused an obvious adverse behavioural reaction within two hours. In no patient was any change in behaviour noted either ...

  9. Allergic reactions in anaesthesia

    DEFF Research Database (Denmark)

    Krøigaard, M; Garvey, L H; Menné, T

    2005-01-01

    match, the right substance being suspected, but investigations showed an additional allergen or several substances, including the right substance being suspected. CONCLUSIONS: An informed guess is not a reliable way of determining the cause of a supposed allergic reaction during anaesthesia and may put...... a significant number of patients at unnecessary risk. Some patients may be labelled with a wrong allergy, leading to unnecessary warnings against harmless substances, and some patients may be put at risk of subsequent re-exposure to the real allergen. Patients with suspected allergic reactions during...

  10. Introduction to nuclear reactions

    International Nuclear Information System (INIS)

    Satchler, G.R.

    1980-01-01

    This introduction to nuclear reaction phenomena is aimed primarily but not exclusively at readers at the undergraduate student level. An overview of the subject is presented in the first two chapters entitled - Some background information and Introduction to nuclear reactions. The third chapter reviews scattering theory with emphasis on the underlying physical ideas and also provides schematic entrees to the more advanced topics. The physical models which have been developed to account for the various aspects of nuclear phenomena are described in more detail in chapter 4. References and exercises are appended to each chapter. (U.K.)

  11. Modeling of Reaction Calorimeter

    OpenAIRE

    Farzad, Reza

    2014-01-01

    The purpose of this project was to model the reaction calorimeter in order to calculate the heat of absorption which is the most important parameter in this work. Reaction calorimeter is an apparatus which is used in measuring the heat of absorption of CO2 as well as the total pressure in vapor phase based on vapor-liquid equilibrium state. Mixture of monoethanolamine (MEA) and water was used as a solvent to absorb the CO2.Project was divided in to three parts in order to make the programming...

  12. Anniversary reactions in therapists.

    Science.gov (United States)

    Granet, R B; Kalman, T P

    1982-12-01

    The authors provide three case examples of anniversary reactions in psychotherapists evoked in the course of treating patients. They note that psychotherapy has always been discussed in terms of time and phases, which lend themselves to periodicities and may provide the potential for anniversary phenomena. The authors recommend that therapists be aware of such phenomena; monitor their own losses, defenses, and dreams; and continue their own supervision. Possible positive aspects of identification of therapists' anniversary reactions are increased empathy with patients and help in completing unresolved therapeutic and personal issues.

  13. Reaction Decoder Tool (RDT): extracting features from chemical reactions

    OpenAIRE

    Rahman, Syed Asad; Torrance, Gilliean; Baldacci, Lorenzo; Mart?nez Cuesta, Sergio; Fenninger, Franz; Gopal, Nimish; Choudhary, Saket; May, John W.; Holliday, Gemma L.; Steinbeck, Christoph; Thornton, Janet M.

    2016-01-01

    Summary: Extracting chemical features like Atom?Atom Mapping (AAM), Bond Changes (BCs) and Reaction Centres from biochemical reactions helps us understand the chemical composition of enzymatic reactions. Reaction Decoder is a robust command line tool, which performs this task with high accuracy. It supports standard chemical input/output exchange formats i.e. RXN/SMILES, computes AAM, highlights BCs and creates images of the mapped reaction. This aids in the analysis of metabolic pathways and...

  14. Reaction Formulation: A Bibliography.

    Science.gov (United States)

    Pedrini, D. T.; Pedrini, Bonnie C.

    Reaction formation was studied by Sigmund Freud. This defense mechanism may be related to repression, substitution, reversal, and compensation (or over-compensation). Alfred Adler considered compensation a basic process in his individual psychology. Anna Freud discussed some defense mechanisms, and Bibring, Dwyer, Huntington, and Valenstein…

  15. Cluster knockout reactions

    Indian Academy of Sciences (India)

    2014-04-07

    Apr 7, 2014 ... Cluster knockout reactions are expected to reveal the amount of clustering (such as that of , d and even of heavier clusters such as 12C, 16O etc.) in the target nucleus. In simple terms, incident medium high-energy nuclear projectile interacts strongly with the cluster (present in the target nucleus) as if it ...

  16. Polymerase chain reaction system

    Science.gov (United States)

    Benett, William J.; Richards, James B.; Stratton, Paul L.; Hadley, Dean R.; Milanovich, Fred P.; Belgrader, Phil; Meyer, Peter L.

    2004-03-02

    A portable polymerase chain reaction DNA amplification and detection system includes one or more chamber modules. Each module supports a duplex assay of a biological sample. Each module has two parallel interrogation ports with a linear optical system. The system is capable of being handheld.

  17. Reaction product imaging

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, D.W. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    Over the past few years the author has investigated the photochemistry of small molecules using the photofragment imaging technique. Bond energies, spectroscopy of radicals, dissociation dynamics and branching ratios are examples of information obtained by this technique. Along with extending the technique to the study of bimolecular reactions, efforts to make the technique as quantitative as possible have been the focus of the research effort. To this end, the author has measured the bond energy of the C-H bond in acetylene, branching ratios in the dissociation of HI, the energetics of CH{sub 3}Br, CD{sub 3}Br, C{sub 2}H{sub 5}Br and C{sub 2}H{sub 5}OBr dissociation, and the alignment of the CD{sub 3} fragment from CD{sub 3}I photolysis. In an effort to extend the technique to bimolecular reactions the author has studied the reaction of H with HI and the isotopic exchange reaction between H and D{sub 2}.

  18. Explaining competitive reaction effects

    NARCIS (Netherlands)

    Leeflang, P.S.H.; Wittink, D.R.

    Changes in promotional expenditure decisions for a brand, as in other marketing decisions, should be based on the expected impact on purchase and consumption behavior as well as on the likely reactions by competitors. Purchase behavior may be predicted from estimated demand functions. Competitive

  19. Cutaneous adverse drug reactions

    African Journals Online (AJOL)

    limiting but they can be the initial presentation of more serious reactions such as Stevens-Johnson and drug hypersensitivity syndromes.3 It is thus important for the clinician to distinguish between self-limiting morbilliform drug eruptions that resolve solely with the withdrawal of the offending drug and the life-threatening ...

  20. Michaelis–Arbuzov reaction

    Indian Academy of Sciences (India)

    agriculture, medicine and synthetic chemistry as cata- lysts and synthetic ... ophile with an electrophilic carbon2 have been found in many synthetic ... problems. Catalytic methods play a special role in synthetic organic chemistry for progress of the reactions in sim- ple fashion. Therefore, researchers have developed var-.

  1. Managing Your Emotional Reactions

    Science.gov (United States)

    ... this situation: Your friends have received promposals (or college acceptances, team places, etc.). But you haven't. Once you identify, ... each one. Which reaction would lead to the best outcome? We always have a ... that work out well. Learning to react well takes practice. But we all ...

  2. [Allergic reactions during anesthesia].

    Science.gov (United States)

    Escolano, F; Sierra, P

    1996-01-01

    Anaphylactic reaction during anesthesia is a constant source of concern for anesthesiologists, given that the rates of death and serious complications are high and predicting which patients will be susceptible is impossible. All substances used in the perioperative period carry a certain risk of releasing histamine and triggering an allergic reaction, though muscle relaxants are the drugs usually implicated. The incidence of serious anaphylaxis ranges between 1:4,000 and 1:23,000 anesthetic procedures, with mortality set at 3-9% and morbidity 10 times higher. Clinical signs vary from mild symptoms to anaphylactic shock and cardiac arrest. The diagnostic procedure to follow upon observing an allergic reaction is to first identify the responsible mechanism and later the responsible agent, as well as drugs that can be used safely. Prophylaxis is based mainly on recognizing predisposed patients before surgery and following recommendations and pharmacological protocols based on better understanding of the pathophysiological mechanisms that cause anaphylactic reaction and on experience in managing them.

  3. Multicomponent reactions in polymer synthesis.

    Science.gov (United States)

    Kakuchi, Ryohei

    2014-01-03

    More participants, yet efficient reactions: Multicomponent reactions (MCRs) have found application in polymer chemistry both in the synthesis of multifunctional monomers and in post-polymerization modification. Examples include the Passerini three-component reaction, the Ugi four-component reaction, and the copper-catalyzed MCR. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. What Is a Reaction Rate?

    Science.gov (United States)

    Schmitz, Guy

    2005-01-01

    The definition of reaction rate is derived and demonstrations are made for the care to be taken while using the term. Reaction rate can be in terms of a reaction property, the extent of reaction and thus it is possible to give a definition applicable in open and closed systems.

  5. Nuclear reactions in astrophysics

    International Nuclear Information System (INIS)

    Cardenas, M.

    1976-01-01

    It is revised the nuclear reactions which present an interest in astrophysics regarding the explanation of some problems such as the relative quantity of the elements, the structure and evolution of the stars. The principal object of the study is the determination of the experimental possibilities in the field of astrophysics, of an accelerator Van de Graaff's 700 KeV type. Two hundred nuclear reactions approximately, were found, and nothing or very little has been done in the intervals of energy which are of interest. Since the bombardment energies and the involved sections are low in some cases, there are real possibilities, for the largest number of stars to obtain important statistical data with the above mentioned accelerator, taking some necessary precautions. (author)

  6. Reactions to dietary tartrazine.

    Science.gov (United States)

    David, T J

    1987-02-01

    Double blind challenges with tartrazine and benzoic acid were performed in hospital in 24 children whose parents gave a definite history of a purely behavioural immediate adverse reaction to one of these substances. The patients, whose ages ranged from 1.6 to 12.4 years, were on a diet that avoided these items, and in all there was a clear history that any lapse of the diet caused an obvious adverse behavioural reaction within two hours. In no patient was any change in behaviour noted either by the parents or the nursing staff after the administration of placebo or active substances. Twenty two patients returned to a normal diet without problems, but the parents of two children insisted on continuing the diet. While popular belief has it that additives may have harmful behavioural effects, objective verification is required to prevent overdiagnosis.

  7. Adverse reactions to antidepressants

    DEFF Research Database (Denmark)

    Uher, Rudolf; Farmer, Anne; Henigsberg, Neven

    2009-01-01

    (74%), constipation (33%) and weight gain (15%) were associated with nortriptyline treatment. Diarrhoea (9%), insomnia (36%) and yawning (16%) were more common during treatment with escitalopram. Problems with urination and drowsiness predicted discontinuation of nortriptyline. Diarrhoea and decreased......Background: Adverse drug reactions are important determinants of non-adherence to antidepressant treatment, but their assessment is complicated by overlap with depressive symptoms and lack of reliable self-report measures. Aims: To evaluate a simple self-report measure and describe adverse...... comparing escitalopram and nortriptyline. Results: There was good agreement between self-report and psychiatrists' ratings. Most complaints listed as adverse reactions in people with depression were more common when they were medication-free rather than during their treatment with antidepressants. Dry mouth...

  8. Concordant Chemical Reaction Networks

    Science.gov (United States)

    Shinar, Guy; Feinberg, Martin

    2015-01-01

    We describe a large class of chemical reaction networks, those endowed with a subtle structural property called concordance. We show that the class of concordant networks coincides precisely with the class of networks which, when taken with any weakly monotonic kinetics, invariably give rise to kinetic systems that are injective — a quality that, among other things, precludes the possibility of switch-like transitions between distinct positive steady states. We also provide persistence characteristics of concordant networks, instability implications of discordance, and consequences of stronger variants of concordance. Some of our results are in the spirit of recent ones by Banaji and Craciun, but here we do not require that every species suffer a degradation reaction. This is especially important in studying biochemical networks, for which it is rare to have all species degrade. PMID:22659063

  9. Enzyme catalysed tandem reactions.

    Science.gov (United States)

    Oroz-Guinea, Isabel; García-Junceda, Eduardo

    2013-04-01

    To transfer to the laboratory, the excellent efficiency shown by enzymes in Nature, biocatalysis, had to mimic several synthetic strategies used by the living organisms. Biosynthetic pathways are examples of tandem catalysis and may be assimilated in the biocatalysis field for the use of isolated multi-enzyme systems in the homogeneous phase. The concurrent action of several enzymes that work sequentially presents extraordinary advantages from the synthetic point of view, since it permits a reversible process to become irreversible, to shift the equilibrium reaction in such a way that enantiopure compounds can be obtained from prochiral or racemic substrates, reduce or eliminate problems due to product inhibition or prevent the shortage of substrates by dilution or degradation in the bulk media, etc. In this review we want to illustrate the developments of recent studies involving in vitro multi-enzyme reactions for the synthesis of different classes of organic compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Reactions to dietary tartrazine.

    Science.gov (United States)

    David, T J

    1987-01-01

    Double blind challenges with tartrazine and benzoic acid were performed in hospital in 24 children whose parents gave a definite history of a purely behavioural immediate adverse reaction to one of these substances. The patients, whose ages ranged from 1.6 to 12.4 years, were on a diet that avoided these items, and in all there was a clear history that any lapse of the diet caused an obvious adverse behavioural reaction within two hours. In no patient was any change in behaviour noted either by the parents or the nursing staff after the administration of placebo or active substances. Twenty two patients returned to a normal diet without problems, but the parents of two children insisted on continuing the diet. While popular belief has it that additives may have harmful behavioural effects, objective verification is required to prevent overdiagnosis. PMID:3548601

  11. Cluster knockout reactions

    Indian Academy of Sciences (India)

    2014-04-07

    Apr 7, 2014 ... (figure 2), the corresponding α–α t-matrix effective interactions are seen to be widely different (figure 3). 2. Formalism. The finite-range transition matrix element T n,l. BA in the triple differential cross-section [13], d3σ d 1d 2dE1. = Fkin × Sl × |T n,l. BA (kf 1, kf 2, ki)|2 for the (α, 2α) cluster knockout reactions is ...

  12. Flora rapid reaction forces

    Directory of Open Access Journals (Sweden)

    Виктор Васильевич Туганаев

    2015-10-01

    Full Text Available Flora rapid reaction forces ­– there are explerents that have high productivity and weak competitiveness. Their innately functional allocation is to plant disturbed acres as soon as possible preventing by that biosphere homeostasis disturbance. Disturbed acres were used to take place in geological history. Nowadays they take especially big areas. Considering a historical line of Dactylis glomerata L. authors suggest to separate out an especial group of anthropochores which they call medieophytes

  13. Photochemical reaction dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Moore, B.C. [Lawrence Berkeley Laboratory, Livermore, CA (United States)

    1993-12-01

    The purpose of the program is to develop a fundamental understanding of unimolecular and bimolecular reaction dynamics with application in combustion and energy systems. The energy dependence in ketene isomerization, ketene dissociation dynamics, and carbonyl substitution on organometallic rhodium complexes in liquid xenon have been studied. Future studies concerning unimolecular processes in ketene as well as energy transfer and kinetic studies of methylene radicals are discussed.

  14. Adverse cutaneous drug reaction

    Directory of Open Access Journals (Sweden)

    Nayak Surajit

    2008-01-01

    Full Text Available In everyday clinical practice, almost all physicians come across many instances of suspected adverse cutaneous drug reactions (ACDR in different forms. Although such cutaneous reactions are common, comprehensive information regarding their incidence, severity and ultimate health effects are often not available as many cases go unreported. It is also a fact that in the present world, almost everyday a new drug enters market; therefore, a chance of a new drug reaction manifesting somewhere in some form in any corner of world is unknown or unreported. Although many a times, presentation is too trivial and benign, the early identification of the condition and identifying the culprit drug and omit it at earliest holds the keystone in management and prevention of a more severe drug rash. Therefore, not only the dermatologists, but all practicing physicians should be familiar with these conditions to diagnose them early and to be prepared to handle them adequately. However, we all know it is most challenging and practically difficult when patient is on multiple medicines because of myriad clinical symptoms, poorly understood multiple mechanisms of drug-host interaction, relative paucity of laboratory testing that is available for any definitive and confirmatory drug-specific testing. Therefore, in practice, the diagnosis of ACDR is purely based on clinical judgment. In this discussion, we will be primarily focusing on pathomechanism and approach to reach a diagnosis, which is the vital pillar to manage any case of ACDR.

  15. Modelling Tethered Enzymatic Reactions

    Science.gov (United States)

    Solis Salas, Citlali; Goyette, Jesse; Coker-Gordon, Nicola; Bridge, Marcus; Isaacson, Samuel; Allard, Jun; Maini, Philip; Dushek, Omer

    Enzymatic reactions are key to cell functioning, and whilst much work has been done in protein interaction in cases where diffusion is possible, interactions of tethered proteins are poorly understood. Yet, because of the large role cell membranes play in enzymatic reactions, several reactions may take place where one of the proteins is bound to a fixed point in space. We develop a model to characterize tethered signalling between the phosphatase SHP-1 interacting with a tethered, phosphorylated protein. We compare our model to experimental data obtained using surface plasmon resonance (SPR). We show that a single SPR experiment recovers 5 independent biophysical/biochemical constants. We also compare the results between a three dimensional model and a two dimensional model. The work gives the opportunity to use known techniques to learn more about signalling processes, and new insights into how enzyme tethering alters cellular signalling. With support from the Mexican Council for Science and Technology (CONACyT), the Public Education Secretariat (SEP), and the Mexican National Autonomous University's Foundation (Fundacion UNAM).

  16. Polyneutron Chain Reactions

    International Nuclear Information System (INIS)

    John C. Fisher

    2000-01-01

    Although helium atoms do not form molecules, a sufficiently large number will bind into a stable liquid droplet. A comparable situation is expected for neutrons, with a sufficiently large number binding into a stable droplet of neutron matter. Such polyneutron droplets can be viewed as isotopes of an element with nuclear charge Z=0, tentatively denoted neutrium, symbol Nt. Because of the relatively weak binding of neutrons compared with that of a mix of neutrons and protons, the minimum number of neutrons required for stability of a droplet is fairly large. Early estimates of ∼60 may be reduced to a dozen or so by the BCS pairing interaction. The Nt entries with N≥12 are new to the table of isotopes. Because all of them are beta-unstable, none is expected to persist as a free particle. Yet, some may occasionally be produced by means to be described below, and it is of interest to examine their decay chains and their interactions with charged nuclei to ascertain how their presence might be revealed. Although these reactions are interesting, they cannot be taken seriously without identifying a source for the initial Nt isotope that begins the chain. Here, we consider possible interactions between 16 O and A Nt. Although there is no strong interaction between them, we can expect a very weak residual attraction that can form a loosely bound 16 O A Nt nuclear molecule. This is not a compound nucleus in the usual sense because, considered as fluids, the 16 O and A Nt droplets are immiscible. For a droplet with fewer than about 60 neutrons, beta decay of A Nt is prevented by the buildup of Coulomb energy associated with transforming A Nt into A H in close proximity to 16 O. Thus, it is possible that 16 O A Nt molecules can persist indefinitely and that a few of them may be present in ordinary water as supermassive oxygen nuclei. Because the binding of these molecules is weak, the A Nt component can tunnel to an adjacent nucleus, and if the adjacent nucleus is 18 O, a

  17. Boron atom reactions

    International Nuclear Information System (INIS)

    Estes, R.; Tabacco, M.B.; Digiuseppe, T.G.; Davidovits, P.

    1982-01-01

    The reaction rates of atomic boron with various epoxides have been measured in a flow tube apparatus. The bimolecular rate constants, in units of cm 3 molecule -1 s -1 , are: 1,2-epoxypropane (8.6 x 10 -11 ), 1,2-epoxybutane (8.8 x 10 -11 ), 1,2,3,4-diepoxybutane (5.5 x 10 -11 ), 1-chloro-2,3-epoxypropane (5.7 x 10 -11 ), and 1,2-epoxy-3,3,3-trichloropropane (1.5 x 10 -11 ). (orig.)

  18. Microfluidic polymerase chain reaction

    Science.gov (United States)

    Maltezos, George; Gomez, Alvaro; Zhong, Jiang; Gomez, Frank A.; Scherer, Axel

    2008-12-01

    We implement microfluidic technology to miniaturize a thermal cycling system for amplifying DNA fragments. By using a microfluidic thermal heat exchanger to cool a Peltier junction, we have demonstrated rapid heating and cooling of small volumes of solution. We use a miniature K-type thermocouple to provide a means for in situ sensing of the temperature inside the microrefrigeration system. By combining the thermocouple, two power supplies controlled by a relay system, and computer automation, we reproduce the function of a commercial polymerase chain reaction thermal cycler and demonstrate amplification of a DNA sample of about 1000 base pairs.

  19. Low Energy Nuclear Reactions?

    CERN Multimedia

    CERN. Geneva; Faccini, R.

    2014-01-01

    After an introduction to the controversial problem of Low Energy Nuclear Reactions (LENR) catalyzed by neutrons on metallic hydride surfaces we present the results of an experiment, made in collaboration with ENEA Labs in Frascati, to search neutrons from plasma discharges in electrolytic cells. The negative outcome of our experiment goes in the direction of ruling out those theoretical models expecting LENR to occur in condensed matter systems under specific conditions. Our criticism on the theoretical foundations of such models will also be presented.

  20. (d,pγ) Reactions and the surrogate reaction technique

    International Nuclear Information System (INIS)

    Cizewski, J.A.; Hatarik, R.; Jones, K.L.; Pain, S.D.; Thomas, J.S.; Johnson, M.S.; Bardayan, D.W.; Blackmon, J.C.; Smith, M.S.; Kozub, R.L.

    2007-01-01

    Neutron-capture reactions on neutron-rich nuclei are important to understand r-process nucleosynthesis, as well as applied needs such as stewardship science and nuclear energy. Because of the short half-lives of these species, it is not possible to measure these reactions directly with neutron beams on unstable targets. The (d,pγ) reaction with radioactive ion beams has been proposed as a surrogate reaction for (n,γ). Experiments to develop (d,pγ) techniques with radioactive ion beams and to demonstrate the efficacy of the (d,pγ) reaction as a surrogate for (n,γ) are discussed

  1. Hydrogen isotope exchange reactions

    International Nuclear Information System (INIS)

    Jones, J.R.

    1980-01-01

    The two most widely used methods for following hydrogen isotope exchange reactions, namely dedeuteriation and detritiation, involve in the first place the synthesis of an appropriately labelled compound. Rates of dedeuteriation are usually followed by measuring changes in the 1 H n.m.r. spectrum of the substrate (examples are given); the method not only gives the rate but also the site(s) of exchange. It is limited to rather slow reactions and is not as accurate as some of the other methods. The development of deuterium n.m.r. spectroscopy means that changes in the 2 H n.m.r. spectrum can also be used to measure rates of dedeuteriation. The development of liquid scintillation counting greatly eased the problem of how to detect weak β emitters; the attractions of tritium as a tracer were thereby much enhanced. Nowadays the study of rates of detritiation constitutes one of the most versatile and accurate methods of following hydrogen isotope exchange. Examples of the technique are given. (U.K.)

  2. The nuclear reaction matrix

    International Nuclear Information System (INIS)

    Krenciglowa, E.M.; Kung, C.L.; Kuo, T.T.S.; Osnes, E.; and Department of Physics, State University of New York at Stony Brook, Stony Brook, New York 11794)

    1976-01-01

    Different definitions of the reaction matrix G appropriate to the calculation of nuclear structure are reviewed and discussed. Qualitative physical arguments are presented in support of a two-step calculation of the G-matrix for finite nuclei. In the first step the high-energy excitations are included using orthogonalized plane-wave intermediate states, and in the second step the low-energy excitations are added in, using harmonic oscillator intermediate states. Accurate calculations of G-matrix elements for nuclear structure calculations in the Aapprox. =18 region are performed following this procedure and treating the Pauli exclusion operator Q 2 /sub p/ by the method of Tsai and Kuo. The treatment of Q 2 /sub p/, the effect of the intermediate-state spectrum and the energy dependence of the reaction matrix are investigated in detail. The present matrix elements are compared with various matrix elements given in the literature. In particular, close agreement is obtained with the matrix elements calculated by Kuo and Brown using approximate methods

  3. Nuclear reaction matrix

    International Nuclear Information System (INIS)

    Krenciglowa, E.M.; Kung, C.L.; Kuo, T.T.S.; Osnes, E.

    1975-01-01

    Different definitions of the reaction matrix G appropriate to the calculation of nuclear structure are reviewed and discussed. Qualitative physical arguments are presented in support of a two-step calculation of the G-matrix for finite nuclei. In the first step the high-energy excitations are included using orthogonalized plane-wave intermediate states, and in the second step the low-energy excitations are added in, using harmonic oscillator intermediate states. Accurate calculations of G-matrix elements for nuclear structure calculations in the A approximately 18 region are performed following this procedure and treating the Pauli exclusion operator Q/sub 2p/ by the method of Tsai and Kuo. The treatment of Q/sub 2p/, the effect of the intermediate-state spectrum and the energy dependence of the reaction matrix are investigated in detail. The present matrix elements are compared with various matrix elements given in the literature. In particular, close argument is obtained with the matrix elements calculated by Kuo and Brown using approximate methods

  4. Reaction Decoder Tool (RDT): extracting features from chemical reactions.

    Science.gov (United States)

    Rahman, Syed Asad; Torrance, Gilliean; Baldacci, Lorenzo; Martínez Cuesta, Sergio; Fenninger, Franz; Gopal, Nimish; Choudhary, Saket; May, John W; Holliday, Gemma L; Steinbeck, Christoph; Thornton, Janet M

    2016-07-01

    Extracting chemical features like Atom-Atom Mapping (AAM), Bond Changes (BCs) and Reaction Centres from biochemical reactions helps us understand the chemical composition of enzymatic reactions. Reaction Decoder is a robust command line tool, which performs this task with high accuracy. It supports standard chemical input/output exchange formats i.e. RXN/SMILES, computes AAM, highlights BCs and creates images of the mapped reaction. This aids in the analysis of metabolic pathways and the ability to perform comparative studies of chemical reactions based on these features. This software is implemented in Java, supported on Windows, Linux and Mac OSX, and freely available at https://github.com/asad/ReactionDecoder : asad@ebi.ac.uk or s9asad@gmail.com. © The Author 2016. Published by Oxford University Press.

  5. Ion-Molecule Reaction Dynamics.

    Science.gov (United States)

    Meyer, Jennifer; Wester, Roland

    2017-05-05

    We review the recent advances in the investigation of the dynamics of ion-molecule reactions. During the past decade, the combination of single-collision experiments in crossed ion and neutral beams with the velocity map ion imaging detection technique has enabled a wealth of studies on ion-molecule reactions. These methods, in combination with chemical dynamics simulations, have uncovered new and unexpected reaction mechanisms, such as the roundabout mechanism and the subtle influence of the leaving group in anion-molecule nucleophilic substitution reactions. For this important class of reactions, as well as for many fundamental cation-molecule reactions, the information obtained with crossed-beam imaging is discussed. The first steps toward understanding micro-solvation of ion-molecule reaction dynamics are presented. We conclude with the presentation of several interesting directions for future research.

  6. Kinetics of Bio-Reactions

    DEFF Research Database (Denmark)

    Villadsen, John

    2015-01-01

    . The models can be used in mass balances for design of processes under process conditions not yet studied experimentally. The value of the predictive kinetic model depends on the quality of the experimental data on which the model is based, and well-founded kinetic models for enzyme reactions have...... a considerable predictive power. This is also true for cell reaction models, when the model is used in its proper context. The chapter first discusses the kinetics for enzymatically catalyzed reactions (“enzyme reactions”). The kinetics can be derived from a mechanistic model. Then, the chapter derives empirical......his chapter predicts the specific rates of reaction by means of a mathematical expression, the kinetics of the reaction. This expression can be derived through a mechanistic interpretation of an enzymatically catalyzed reaction, but it is essentially of empirical nature for cell reactions...

  7. The Glaser–Hay reaction

    DEFF Research Database (Denmark)

    Vilhelmsen, Mie Højer; Jensen, Jonas; Tortzen, Christian

    2013-01-01

    . This unfavorable change in reaction profile could be avoided by adding molecular sieves to the reaction mixture, thereby removing the water that is accumulated from the air and produced in the reaction in which dioxygen acts as the oxidizing agent. Not unexpectedly, the stirring rate, and hence uptake of air (O2......), was found to have a significant effect on the rate of the reaction: The percentage of alkyne remaining after a certain time decreased linearly with the rate of stirring. On the basis of systematic studies, the optimized conditions for the coupling reaction using CuCl/TMEDA as the catalyst system......The oxidative Glaser–Hay coupling of two terminal alkynes to furnish a butadiyne is a key reaction for acetylenic scaffolding. Although the reaction is performed under rather simple conditions [CuCl/TMEDA/O2 (air)], the mechanism is still under debate. Herein we present detailed studies...

  8. Nuclear reactions an introduction

    CERN Document Server

    Paetz gen. Schieck, Hans

    2014-01-01

    Nuclei and nuclear reactions offer a unique setting for investigating three (and in some cases even all four) of the fundamental forces in nature. Nuclei have been shown – mainly by performing scattering experiments with electrons, muons, and neutrinos – to be extended objects with complex internal structures: constituent quarks; gluons, whose exchange binds the quarks together; sea-quarks, the ubiquitous virtual quark-antiquark pairs and, last but not least, clouds of virtual mesons, surrounding an inner nuclear region, their exchange being the source of the nucleon-nucleon interaction.   The interplay between the (mostly attractive) hadronic nucleon-nucleon interaction and the repulsive Coulomb force is responsible for the existence of nuclei; their degree of stability, expressed in the details and limits of the chart of nuclides; their rich structure and the variety of their interactions. Despite the impressive successes of the classical nuclear models and of ab-initio approaches, there is clearly no ...

  9. Chemical Reactions in Nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Levdansky, V.V.; Smolík, Jiří; Moravec, Pavel

    2010-01-01

    Roč. 83, č. 2 (2010), s. 401-405 ISSN 1062-0125 R&D Projects: GA ČR GA101/09/1633; GA AV ČR(CZ) IAA400720804; GA MPO(CZ) FR-TI1/548 Institutional research plan: CEZ:AV0Z40720504 Keywords : nanoparticle * chemical reaction * size effect Subject RIV: CF - Physical ; Theoretical Chemistry http://www.scopus.com/record/display.url?eid=2-s2.0-77955925089&origin=resultslist&sort=plf-f& src =s&st1=smolik%2cj&sid=j7atgxrpM26F0dojYSZsugJ%3a170&sot=b&sdt=b&sl=21&s=AUTHOR-NAME%28smolik%2cj%29&relpos=10&relpos=10&searchTerm=AUTHOR-NAME(smolik,j)

  10. Reversible and irreversible reaction fronts in two competing reactions system

    International Nuclear Information System (INIS)

    Sinder, M.; Taitelbaum, H.; Pelleg, J.

    2002-01-01

    A modeling of the non-equilibrium diffusion phenomena of the impurities in the semiconductors is based on the reaction-diffusion equations for local concentrations of the components. Through this approach a new feature, a reaction front, may be caused by reaction in diffusion profiles of the components. The asymptotic long-time properties of the reaction fronts in the system with initially separated components and two competing reactions: reversible A 1 +B↔C 1 and irreversible A 2 +B→C 2 are studied in this work. It is assumed that the backward constant of the reaction A 1 +B↔C 1 is small. The dynamics of the system is described as a cross-over between the 'irreversible' regime for small times and the 'reversible' regime for large times. It is shown that the 'irreversible' regime is characterized by single reaction zone, in which both reactions occur. The two reaction fronts, reversible A 1 +B↔C 1 and irreversible A 2 +C 1 →A 1 +C 2 appear in the 'reversible' regime. Numerical computing of the mean-field kinetics equations confirms these asymptotic results. The experimental tests of the theoretical predictions relating to the diffusion phenomena in semiconductors are discussed

  11. Immediate hypersensitivity reaction with mango.

    Science.gov (United States)

    Shah, Ashok; Gera, Kamal

    2014-01-01

    Hypersensitivity to the fruit mango is extremely rare and can exhibit either as immediate or delayed reactions. Since 1939, only 22 patients (10 with immediate type I reactions and 12 with delayed) have been documented with allergy to mango. History of atopy and geographical region may influence the type of reaction. Immediate reactions occurred most often in patients with history of atopy, while delayed reactions developed in non-atopic individuals. Clustering of delayed hypersensitivity reports from Australia and immediate reactions from Europe has been documented. We report a 50-year-old man with immediate type I hypersensitivity to mango, who developed cough, wheezing dyspnoea, generalised itching and abdominal discomfort after ingestion of mango. Life threatening event can also happen making it imperative to diagnose on time, so as to prevent significant morbidity and potential mortality.

  12. Adverse Reactions to Biologic Therapy.

    Science.gov (United States)

    Patel, Sheenal V; Khan, David A

    2017-05-01

    Biologic therapies are emerging as a significant therapeutic option for many with debilitating inflammatory and autoimmune conditions. As expansion in the number of FDA-approved agents continue to be seen, more unanticipated adverse reactions are likely to occur. Currently, the diagnostic tools, including skin testing and in vitro testing, to evaluate for immediate hypersensitivity reactions are insufficient. In this review, management strategies for common acute infusion reactions, injection site reactions, and immediate reactions suggestive of IgE-mediated mechanisms are discussed. Desensitization can be considered for reactions suggestive of IgE-mediated mechanisms, but allergists/immunologists should be involved in managing these patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. [Adverse cutaneous reactions to drugs].

    Science.gov (United States)

    Suástegui-Rodríguez, Irvin; Campos-Jiménez, Karin Ivette; Domínguez-Cherit, Judith; Méndez-Flores, Silvia

    2018-01-01

    Adverse cutaneous reactions to drugs are any undesirable change in the structure or function of the skin. These are among the adverse side effects to common drugs. The most commonly implicated drugs are antibiotics and anticonvulsants. Cutaneous clinical manifestations are diverse ranging from mild or moderate reactions, such as urticaria and maculopapular rash, to severe cutaneous adverse reactions (SCAR), which are known due to their high morbidity and mortality (among these: Stevens-Johnson syndrome, toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS). The clinical pattern, etiology, prognosis and treatment differ among these skin reactions, which is why it is necessary a clear diagnosis based on a comprehensive clinical examination, skin biopsy, and specific laboratory tests. The therapeutic options depend on the clinical diagnosis. For all reactions, a symptomatic and adequate supportive therapy is necessary; in some cases, a systemic immunomodulatory therapy can be useful.

  14. Nuclear reactions as structure probes

    International Nuclear Information System (INIS)

    Fernandez, Bernard; Cugnon, Joseph; Roussel-Chomaz, Patricia; Sparenberg, Jean-Marc; Oliveira Santos, Francois de; Bauge, Eric; Poves, Alfredo; Keeley, Nicholas; Simenel, Cedric; Avez, Benoit; Lacroix, Denis; Baye, Daniel; Cortina-Gil, Dolores; Pons, Alexandre

    2007-09-01

    This publication gathers courses which aim at giving a view on new experiments which are performed by using radioactive beams, notably low intensity beams, in different accelerators, and allow the structure of very exotic nuclei to be characterized. Experimental as well as theoretical aspects are thus addressed. The contributions propose: a brief history of nuclear reactions and of instruments used to study them from the discovery of nucleus to the DWBA (Distorted Wave Born Approximation); an overview of nuclear reactions; experimental techniques; the theory of collisions at low energy; resonant elastic scattering, inelastic scattering and astrophysical reactions; to probe nuclear structure with nucleons; shell model and spectroscopic factors; analysis of transfer reactions and determination of spectroscopic factors; microscopic approaches of nuclear dynamics; theoretical aspects of dissociation reactions; experimental aspects of knockout reactions; research in oenology with the chemical characterisation of defective ageing of dry white wines

  15. Nuclear astrophysics from direct reactions

    Energy Technology Data Exchange (ETDEWEB)

    Bertulani, C. [Department of Physics, Texas A and M University, Commerce, TX 75429 (United States)]. e-mail: carlos_bertulani@tamu-commerce.edu

    2008-12-15

    Accurate nuclear reaction rates are needed for primordial nucleosynthesis and hydrostatic burning in stars. The relevant reactions are extremely difficult to measure directly in the laboratory at the small astrophysical energies. In recent years direct reactions have been developed and applied to extract low-energy astrophysical S-factors. These methods require a combination of new experimental techniques and theoretical efforts, which are the subject of this presentation. (Author)

  16. Multistep processes in nuclear reactions

    International Nuclear Information System (INIS)

    Hodgson, P.E.

    1988-01-01

    The theories of nuclear reactions are reviewed with particular attention to the recent work on multistep processes. The evidence for compound nucleus and direct interaction reactions is described together with the results of comparisons between theories and experimental data. These theories have now proved inadequate, and there is evidence for multistep processes that take place after the initial direct stage but long before the attainment of the statistical equilibrium characteristic of compound nucleus processes. The theories of these reactions are described and it is shown how they can account for the experimental data and thus give a comprehensive understanding of nuclear reactions. (author)

  17. Dynamic Reaction Figures: An Integrative Vehicle for Understanding Chemical Reactions

    Science.gov (United States)

    Schultz, Emeric

    2008-01-01

    A highly flexible learning tool, referred to as a dynamic reaction figure, is described. Application of these figures can (i) yield the correct chemical equation by simply following a set of menu driven directions; (ii) present the underlying "mechanism" in chemical reactions; and (iii) help to solve quantitative problems in a number of different…

  18. Free Radical Reactions in Food.

    Science.gov (United States)

    Taub, Irwin A.

    1984-01-01

    Discusses reactions of free radicals that determine the chemistry of many fresh, processed, and stored foods. Focuses on reactions involving ascorbic acid, myoglobin, and palmitate radicals as representative radicals derived from a vitamin, metallo-protein, and saturated lipid. Basic concepts related to free radical structure, formation, and…

  19. Adverse Reactions to Hallucinogenic Drugs.

    Science.gov (United States)

    Meyer, Roger E. , Ed.

    This reports a conference of psychologists, psychiatrists, geneticists and others concerned with the biological and psychological effects of lysergic acid diethylamide and other hallucinogenic drugs. Clinical data are presented on adverse drug reactions. The difficulty of determining the causes of adverse reactions is discussed, as are different…

  20. "Greening up" the Suzuki Reaction

    Science.gov (United States)

    Aktoudianakis, Evangelos; Chan, Elton; Edward, Amanda R.; Jarosz, Isabel; Lee, Vicki; Mui, Leo; Thatipamala, Sonya S.; Dicks, Andrew P.

    2008-01-01

    This article describes the rapid, green synthesis of a biaryl compound (4-phenylphenol) via a Pd(0)-catalyzed Suzuki cross-coupling reaction in water. Mild reaction conditions and operational simplicity makes this experiment especially amenable to both mid- and upper-level undergraduates. The methodology exposes students to purely aqueous…

  1. Effective reaction rates for diffusion-limited reaction cycles.

    Science.gov (United States)

    Nałęcz-Jawecki, Paweł; Szymańska, Paulina; Kochańczyk, Marek; Miękisz, Jacek; Lipniacki, Tomasz

    2015-12-07

    Biological signals in cells are transmitted with the use of reaction cycles, such as the phosphorylation-dephosphorylation cycle, in which substrate is modified by antagonistic enzymes. An appreciable share of such reactions takes place in crowded environments of two-dimensional structures, such as plasma membrane or intracellular membranes, and is expected to be diffusion-controlled. In this work, starting from the microscopic bimolecular reaction rate constants and using estimates of the mean first-passage time for an enzyme-substrate encounter, we derive diffusion-dependent effective macroscopic reaction rate coefficients (EMRRC) for a generic reaction cycle. Each EMRRC was found to be half of the harmonic average of the microscopic rate constant (phosphorylation c or dephosphorylation d), and the effective (crowding-dependent) motility divided by a slowly decreasing logarithmic function of the sum of the enzyme concentrations. This implies that when c and d differ, the two EMRRCs scale differently with the motility, rendering the steady-state fraction of phosphorylated substrate molecules diffusion-dependent. Analytical predictions are verified using kinetic Monte Carlo simulations on the two-dimensional triangular lattice at the single-molecule resolution. It is demonstrated that the proposed formulas estimate the steady-state concentrations and effective reaction rates for different sets of microscopic reaction rates and concentrations of reactants, including a non-trivial example where with increasing diffusivity the fraction of phosphorylated substrate molecules changes from 10% to 90%.

  2. Reaction rates for reaction-diffusion kinetics on unstructured meshes.

    Science.gov (United States)

    Hellander, Stefan; Petzold, Linda

    2017-02-14

    The reaction-diffusion master equation is a stochastic model often utilized in the study of biochemical reaction networks in living cells. It is applied when the spatial distribution of molecules is important to the dynamics of the system. A viable approach to resolve the complex geometry of cells accurately is to discretize space with an unstructured mesh. Diffusion is modeled as discrete jumps between nodes on the mesh, and the diffusion jump rates can be obtained through a discretization of the diffusion equation on the mesh. Reactions can occur when molecules occupy the same voxel. In this paper, we develop a method for computing accurate reaction rates between molecules occupying the same voxel in an unstructured mesh. For large voxels, these rates are known to be well approximated by the reaction rates derived by Collins and Kimball, but as the mesh is refined, no analytical expression for the rates exists. We reduce the problem of computing accurate reaction rates to a pure preprocessing step, depending only on the mesh and not on the model parameters, and we devise an efficient numerical scheme to estimate them to high accuracy. We show in several numerical examples that as we refine the mesh, the results obtained with the reaction-diffusion master equation approach those of a more fine-grained Smoluchowski particle-tracking model.

  3. Reaction path analysis of sodium-water reaction phenomena in support of chemical reaction model development

    International Nuclear Information System (INIS)

    Kikuchi, Shin; Ohshima, Hiroyuki; Hashimoto, Kenro

    2011-01-01

    Computational study of the sodium-water reaction at the gas (water) - liquid (sodium) interface has been carried out using ab initio (first-principle) method. A possible reaction channel has been identified for the stepwise OH bond dissociations of a single water molecule. The energetics including the binding energy of a water molecule to the sodium surface, the activation energies of the bond cleavages, and the reaction energies, have been evaluated, and the rate constants of the first and second OH bond-breakings have been compared. The results are used as the basis for constructing the chemical reaction model used in a multi-dimensional sodium-water reaction code, SERAPHIM, being developed by JAEA toward the safety assessment of the steam generator (SG) in a sodium-cooled fast reactor (SFR). (author)

  4. Integrated Microreactors for Reaction Automation: New Approaches to Reaction Development

    Science.gov (United States)

    McMullen, Jonathan P.; Jensen, Klavs F.

    2010-07-01

    Applications of microsystems (microreactors) in continuous-flow chemistry have expanded rapidly over the past two decades, with numerous reports of higher conversions and yields compared to conventional batch benchtop equipment. Synthesis applications are enhanced by chemical information gained from integrating microreactor components with sensors, actuators, and automated fluid handling. Moreover, miniaturized systems allow experiments on well-defined samples at conditions not easily accessed by conventional means, such as reactions at high pressure and temperatures. The wealth of synthesis information that could potentially be acquired through use of microreactors integrated with physical sensors and analytical chemistry techniques for online reaction monitoring has not yet been well explored. The increased efficiency resulting from use of continuous-flow microreactor platforms to automate reaction screening and optimization encourages a shift from current batchwise chemical reaction development to this new approach. We review advances in this new area and provide application examples of online monitoring and automation.

  5. Fusion chain reaction - a chain reaction with charged particles

    International Nuclear Information System (INIS)

    Peres, A.; Shvarts, D.

    1975-01-01

    When a DT-plasma is compressed to very high density, the particles resulting from nuclear reactions give their energy mostly to D and T ions, by nuclear collisions, rather than to electrons as usual. Fusion can thus proceed as a chain reaction, without the need of thermonuclear temperatures. In this paper, we derive relations for the suprathermal ion population created by a fusion reaction. Numerical integration of these equations shows that a chain reaction can proceed in a cold infinite DT-plasma at densities above 8.4x10 27 ions.cm -3 . Seeding the plasma with a small amount of 6 Li reduces the critical density to 7.2x10 27 ions.cm -3 (140000times the normal solid density). (author)

  6. The Paterno-Buchi reaction

    DEFF Research Database (Denmark)

    Brogaard, Rasmus Yding; Schalk, Oliver; Boguslavskiy, Andrey E.

    2012-01-01

    The Paternò-Büchi (PB) reaction between an excited carbonyl compound and an alkene has been widely studied, but so far little is known about the excited-state dynamics of the reaction. In this investigation, we used a compound in which a formyl and a vinyl group are attached to a [2.2]paracycloph......The Paternò-Büchi (PB) reaction between an excited carbonyl compound and an alkene has been widely studied, but so far little is known about the excited-state dynamics of the reaction. In this investigation, we used a compound in which a formyl and a vinyl group are attached to a [2...... within two picoseconds competes efficiently with the reaction in the singlet manifold. Thus, the PB reaction in this model system takes place in the triplet state on a time scale of nanoseconds. This result stresses the importance of triplet states in the excited-state pathway of the PB reaction...

  7. Palladium-catalyzed coupling reactions

    CERN Document Server

    Molnár, Árpád

    2013-01-01

    This handbook and ready reference brings together all significant issues of practical importance for interested readers in one single volume. While covering homogeneous and heterogeneous catalysis, the text is unique in focusing on such important aspects as using different reaction media, microwave techniques or catalyst recycling. It also provides a comprehensive treatment of modern-day coupling reactions and emphasizes those topics that show potential for future development, such as continuous flow systems, water as a reaction medium, and catalyst immobilization, among others. With i

  8. Catalytic Organometallic Reactions of Ammonia

    Science.gov (United States)

    Klinkenberg, Jessica L.

    2012-01-01

    Until recently, ammonia had rarely succumbed to catalytic transformations with homogeneous catalysts, and the development of such reactions that are selective for the formation of single products under mild conditions has encountered numerous challenges. However, recently developed catalysts have allowed several classes of reactions to create products with nitrogen-containing functional groups from ammonia. These reactions include hydroaminomethylation, reductive amination, alkylation, allylic substitution, hydroamination, and cross-coupling. This Minireview describes examples of these processes and the factors that control catalyst activity and selectivity. PMID:20857466

  9. Chemical potential and reaction electronic flux in symmetry controlled reactions.

    Science.gov (United States)

    Vogt-Geisse, Stefan; Toro-Labbé, Alejandro

    2016-07-15

    In symmetry controlled reactions, orbital degeneracies among orbitals of different symmetries can occur along a reaction coordinate. In such case Koopmans' theorem and the finite difference approximation provide a chemical potential profile with nondifferentiable points. This results in an ill-defined reaction electronic flux (REF) profile, since it is defined as the derivative of the chemical potential with respect to the reaction coordinate. To overcome this deficiency, we propose a new way for the calculation of the chemical potential based on a many orbital approach, suitable for reactions in which symmetry is preserved. This new approach gives rise to a new descriptor: symmetry adapted chemical potential (SA-CP), which is the chemical potential corresponding to a given irreducible representation of a symmetry group. A corresponding symmetry adapted reaction electronic flux (SA-REF) is also obtained. Using this approach smooth chemical potential profiles and well defined REFs are achieved. An application of SA-CP and SA-REF is presented by studying the Cs enol-keto tautomerization of thioformic acid. Two SA-REFs are obtained, JA'(ξ) and JA'' (ξ). It is found that the tautomerization proceeds via an in-plane delocalized 3-center 4-electron O-H-S hypervalent bond which is predicted to exist only in the transition state (TS) region. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. Reactions with light exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Lichtenthäler, R.; Faria, P.N. de; Pires, K.C.C.; Lepine-Szily, A.; Guimaraes, V.; Mendes Junior, D.R.; Assuncao, M.; Barioni, A.; Morcelle, V.; Morais, M.C.; Camargo Junior, O.; Alcantara Nuñez, J. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica; Moro, A.M. [Departamento de FAMN, Universidad de Sevilla, Sevilla (Spain); Arazi, A. [Laboratorio Tandar, Departamento de Fisica, Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina); Rodriguez-Gallardo, M. [Instituto de Estructura de la Materia, CSIC, Madrid (Spain)

    2014-07-01

    Experimental cross sections for the {sup 6}He+{sup 120}Sn are analysed. Elastic scattering angular distributions and alpha particle production cross sections have been measured and are compared with the total reaction cross sections. (author)

  11. Method for conducting exothermic reactions

    Science.gov (United States)

    Smith, L. Jr.; Hearn, D.; Jones, E.M. Jr.

    1993-01-05

    A liquid phase process for oligomerization of C[sub 4] and C[sub 5] isoolefins or the etherification thereof with C[sub 1] to C[sub 6] alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300 F. wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

  12. Analysis of kinetic reaction mechanisms

    CERN Document Server

    Turányi, Tamás

    2014-01-01

    Chemical processes in many fields of science and technology, including combustion, atmospheric chemistry, environmental modelling, process engineering, and systems biology, can be described by detailed reaction mechanisms consisting of numerous reaction steps. This book describes methods for the analysis of reaction mechanisms that are applicable in all these fields. Topics addressed include: how sensitivity and uncertainty analyses allow the calculation of the overall uncertainty of simulation results and the identification of the most important input parameters, the ways in which mechanisms can be reduced without losing important kinetic and dynamic detail, and the application of reduced models for more accurate engineering optimizations. This monograph is invaluable for researchers and engineers dealing with detailed reaction mechanisms, but is also useful for graduate students of related courses in chemistry, mechanical engineering, energy and environmental science and biology.

  13. Drug Reactions in Oral Mucosa

    Directory of Open Access Journals (Sweden)

    Emine Derviş

    2012-12-01

    Full Text Available Both immunologic and nonimmunologic drug reactions can be seen in oral mucosa. Since considerable number of these reactions heals spontaneously without being noticed by the patients, exact frequency of the lesions is unknown. Most common lesions are xerostomia, taste disorders, mucosal ulcerations and edema. In this article, oral lesions resulting from drug intake similar to those from oral lesions of local and systemic diseases, and diagnostic problems caused by these similarities, have been reviewed.

  14. Medium effects in direct reactions

    International Nuclear Information System (INIS)

    Karakoc, M; Bertulani, C

    2013-01-01

    We discuss medium corrections of the nucleon-nucleon (NN) cross sections and their influence on direct reactions at intermediate energies ≳50 MeV/nucleon. The results obtained with free NN cross sections are compared with those obtained with a geometrical treatment of Pauli-blocking and Dirac-Bruecker methods. We show that medium corrections may lead to sizable modifications for collisions at intermediate energies and that they are more pronounced in reactions involving weakly bound nuclei.

  15. Late reaction, persistent reaction and doubtful allergic reaction: The problems of interpretation

    Directory of Open Access Journals (Sweden)

    Sarma Nilendu

    2009-01-01

    Full Text Available The standard method of patch test reading is to read the test site for any positive allergy at 48hr and then again at 72/96 hr. A late reading on the seventh day is also advised to exclude the irritant reaction (IR and to notice some delayed development of allergic reaction. However, multiple visits are often difficult for the patient; therefore, this late reading is sometimes omitted. Here a case of plantar hyperkeratosis, due to allergic contact dermatitis, is reported with some insight into interpretation of the patch test. The patient showed delayed patch test reaction to formaldehyde and colophony, which has never been reported before.

  16. Reciprocity theory of homogeneous reactions

    Science.gov (United States)

    Agbormbai, Adolf A.

    1990-03-01

    The reciprocity formalism is applied to the homogeneous gaseous reactions in which the structure of the participating molecules changes upon collision with one another, resulting in a change in the composition of the gas. The approach is applied to various classes of dissociation, recombination, rearrangement, ionizing, and photochemical reactions. It is shown that for the principle of reciprocity to be satisfied it is necessary that all chemical reactions exist in complementary pairs which consist of the forward and backward reactions. The backward reaction may be described by either the reverse or inverse process. The forward and backward processes must satisfy the same reciprocity equation. Because the number of dynamical variables is usually unbalanced on both sides of a chemical equation, it is necessary that this balance be established by including as many of the dynamical variables as needed before the reciprocity equation can be formulated. Statistical transformation models of the reactions are formulated. The models are classified under the titles free exchange, restricted exchange and simplified restricted exchange. The special equations for the forward and backward processes are obtained. The models are consistent with the H theorem and Le Chatelier's principle. The models are also formulated in the context of the direct simulation Monte Carlo method.

  17. Nuclear Reactions for Astrophysics and Other Applications

    Energy Technology Data Exchange (ETDEWEB)

    Escher, J E; Burke, J T; Dietrich, F S; Scielzo, N D; Ressler, J J

    2011-03-01

    Cross sections for compound-nuclear reactions are required for many applications. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f) reactions, but need to be improved upon for applications to capture reactions.

  18. Reaction rates for mesoscopic reaction-diffusion kinetics.

    Science.gov (United States)

    Hellander, Stefan; Hellander, Andreas; Petzold, Linda

    2015-02-01

    The mesoscopic reaction-diffusion master equation (RDME) is a popular modeling framework frequently applied to stochastic reaction-diffusion kinetics in systems biology. The RDME is derived from assumptions about the underlying physical properties of the system, and it may produce unphysical results for models where those assumptions fail. In that case, other more comprehensive models are better suited, such as hard-sphere Brownian dynamics (BD). Although the RDME is a model in its own right, and not inferred from any specific microscale model, it proves useful to attempt to approximate a microscale model by a specific choice of mesoscopic reaction rates. In this paper we derive mesoscopic scale-dependent reaction rates by matching certain statistics of the RDME solution to statistics of the solution of a widely used microscopic BD model: the Smoluchowski model with a Robin boundary condition at the reaction radius of two molecules. We also establish fundamental limits on the range of mesh resolutions for which this approach yields accurate results and show both theoretically and in numerical examples that as we approach the lower fundamental limit, the mesoscopic dynamics approach the microscopic dynamics. We show that for mesh sizes below the fundamental lower limit, results are less accurate. Thus, the lower limit determines the mesh size for which we obtain the most accurate results.

  19. Reaction rates for a generalized reaction-diffusion master equation.

    Science.gov (United States)

    Hellander, Stefan; Petzold, Linda

    2016-01-01

    It has been established that there is an inherent limit to the accuracy of the reaction-diffusion master equation. Specifically, there exists a fundamental lower bound on the mesh size, below which the accuracy deteriorates as the mesh is refined further. In this paper we extend the standard reaction-diffusion master equation to allow molecules occupying neighboring voxels to react, in contrast to the traditional approach, in which molecules react only when occupying the same voxel. We derive reaction rates, in two dimensions as well as three dimensions, to obtain an optimal match to the more fine-grained Smoluchowski model and show in two numerical examples that the extended algorithm is accurate for a wide range of mesh sizes, allowing us to simulate systems that are intractable with the standard reaction-diffusion master equation. In addition, we show that for mesh sizes above the fundamental lower limit of the standard algorithm, the generalized algorithm reduces to the standard algorithm. We derive a lower limit for the generalized algorithm which, in both two dimensions and three dimensions, is of the order of the reaction radius of a reacting pair of molecules.

  20. Concordant Chemical Reaction Networks and the Species-Reaction Graph

    Science.gov (United States)

    Shinar, Guy; Feinberg, Martin

    2015-01-01

    In a recent paper it was shown that, for chemical reaction networks possessing a subtle structural property called concordance, dynamical behavior of a very circumscribed (and largely stable) kind is enforced, so long as the kinetics lies within the very broad and natural weakly monotonic class. In particular, multiple equilibria are precluded, as are degenerate positive equilibria. Moreover, under certain circumstances, also related to concordance, all real eigenvalues associated with a positive equilibrium are negative. Although concordance of a reaction network can be decided by readily available computational means, we show here that, when a nondegenerate network’s Species-Reaction Graph satisfies certain mild conditions, concordance and its dynamical consequences are ensured. These conditions are weaker than earlier ones invoked to establish kinetic system injectivity, which, in turn, is just one ramification of network concordance. Because the Species-Reaction Graph resembles pathway depictions often drawn by biochemists, results here expand the possibility of inferring significant dynamical information directly from standard biochemical reaction diagrams. PMID:22940368

  1. Carbonitriding reactions of diatomaceous earth: phase evolution and reaction mechanisms

    Directory of Open Access Journals (Sweden)

    BRANKO MATOVIC

    2006-06-01

    Full Text Available The possibility of using diatomaceous earth as Si precursor for low temperature synthesis of non-oxide powders by carbothermal reduction-nitridation was studied. It was found that carbonitriding reactions produce phases of the Si–Al–O–N system. Already at 1300 °C, nanosized, non-oxide powders were obtained. The comparatively low reaction temperatures is attributred to the nano-porous nature of the raw material. The evolution of crystalline phases proceeded via many intermediate stages. The powders were characterized by X-ray and SEM investigations. The results showed that diatomaceous earth can be a very effective source for obtaining non-oxide powders.

  2. A comprehensive survey of nuclear reactions; Panorama des reactions nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Cugnon, J. [Liege Univ., IFPA, AGO Dept. (Belgium)

    2007-07-01

    The various mechanisms of nuclear reactions are surveyed and classified in different regimes, based on the notions of coherent mechanisms and hard versus soft processes. The emphasis is put on the concepts at the basis of the understanding of these regimes and on the elements of nuclear structure which are involved in these different regimes, as well as the on the possibility of extracting this information. Due to lack of space and for pedagogical reasons, the discussion is limited to nucleon-induced and light-ion-induced reactions. However, a few remarks are given concerning some specific probes, such as weakly bound projectiles or neutron-rich nuclei. (author)

  3. Biomarkers of adverse drug reactions.

    Science.gov (United States)

    Carr, Daniel F; Pirmohamed, Munir

    2018-02-01

    Adverse drug reactions can be caused by a wide range of therapeutics. Adverse drug reactions affect many bodily organ systems and vary widely in severity. Milder adverse drug reactions often resolve quickly following withdrawal of the casual drug or sometimes after dose reduction. Some adverse drug reactions are severe and lead to significant organ/tissue injury which can be fatal. Adverse drug reactions also represent a financial burden to both healthcare providers and the pharmaceutical industry. Thus, a number of stakeholders would benefit from development of new, robust biomarkers for the prediction, diagnosis, and prognostication of adverse drug reactions. There has been significant recent progress in identifying predictive genomic biomarkers with the potential to be used in clinical settings to reduce the burden of adverse drug reactions. These have included biomarkers that can be used to alter drug dose (for example, Thiopurine methyltransferase (TPMT) and azathioprine dose) and drug choice. The latter have in particular included human leukocyte antigen (HLA) biomarkers which identify susceptibility to immune-mediated injuries to major organs such as skin, liver, and bone marrow from a variety of drugs. This review covers both the current state of the art with regard to genomic adverse drug reaction biomarkers. We also review circulating biomarkers that have the potential to be used for both diagnosis and prognosis, and have the added advantage of providing mechanistic information. In the future, we will not be relying on single biomarkers (genomic/non-genomic), but on multiple biomarker panels, integrated through the application of different omics technologies, which will provide information on predisposition, early diagnosis, prognosis, and mechanisms. Impact statement • Genetic and circulating biomarkers present significant opportunities to personalize patient therapy to minimize the risk of adverse drug reactions. ADRs are a significant heath issue

  4. Spallation reactions - physics and applications

    International Nuclear Information System (INIS)

    Kelic, A.; Ricciardi, M.; Schmidt, K-H.

    2009-01-01

    Spallation reactions have become an ideal tool for studying the equation of state and thermal instabilities of nuclear matter. In astrophysics, the interactions of cosmic rays with the interstellar medium have to be understood in detail for deducing their original composition and their production mechanisms. Renewed interest in spallation reactions with protons around 1 GeV came up recently with the developments of spallation neutron sources. The project of an accelerator-driven system (ADS) as a technological solution for incinerating the radioactive waste even intensified the efforts for better understanding the physics involved in the spallation process. Experiments on spallation reactions were performed for determining the production cross sections and properties of particles, fragments and heavy residues. Traditional experiments on heavy residues, performed in direct kinematics, were limited to the direct observation of long-lived radioactive nuclides and did not provide detailed information on the kinematics of the reaction. Therefore, an innovative experimental method has been developed, based on inverse kinematics, which allowed to identify all reaction residues in-flight, using the high resolution magnetic spectrometer FRS of GSL Darmstadt. It also gives direct access to the reaction kinematics. An experimental campaign has been carried out in a Europe-wide collaboration, investigating the spallation of several nuclei ranging from 56 Fe to 238 U Complementary experiments were performed with a full-acceptance detection system, yielding total fission cross sections. Recently, another detection system using the large acceptance ALADIN dipole and the LAND neutron detector was introduced to measure light particles in coincidence with the heavy residues. Another intense activity was dedicated to developing codes, which cover nuclear reactions occurring in an ADS. The first phase of the reaction is successfully described by a sequence of quasi-free nucleon

  5. [Histopathology of cutaneous drug reactions].

    Science.gov (United States)

    Ortonne, Nicolas

    2018-02-01

    There are many different types of cutaneous adverse reactions. The most classical reactions are driven by T lymphocytes that specifically react towards a drug, with an individual genetic susceptibility linked to certain type I major histocompatibility complex alleles. These reactions are characterized by a wide variety of clinical and histopathological presentations, and a wide range of severity. The most frequent entity is the maculopapular rash, while the most aggressive forms are the Steven-Johnson syndrome and toxic epidermal necrolysis (SJS-TEN). The histopathological alterations associated to each of these syndromes have been better described in the literature during the past 10 years, encompassing non-specific lesions, as in most drug induced maculopapular rashes, to more specific inflammatory patterns. The finding of confluent apoptotic keratinocytes with epidermal detachment is the prototypical aspect of SJS-TEN. There are however numerous pitfalls, and a similar aspect to those observed in each cutaneous drug reactions entities can be found in other diseases. DRESS syndrome can indeed present with dense and epidermotropic T-cell infiltrate, sometimes with nuclear atypias, and thus can be difficult to distinguish from a primary or secondary cutaneous T-cell lymphoma. The diagnosis of cutaneous adverse reactions relies on a clinical-pathological confrontation and requires an accurate evaluation of drug imputability. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  6. Fatal anaphylactic reaction during anesthesia

    Directory of Open Access Journals (Sweden)

    Izidor Kern

    2012-01-01

    Full Text Available Background: Incidence of anaphylactic reactions occuring during anesthesia is not known. They occur most often in the induction  phase and can present with different levels of severity, also as an anaphylactic shock. Neuromuscular blocking drugs are the most frequently involved substances.Case presentation: We  report a case of a 77-year old female patient with granulomatous inflammation of unknown etiology. Surgical  biopsy of a neck lymph node was indicated. During the induction of anesthesia using propofol and succinylcholine she developed severe anaphylactic reaction presented with bronchospasm and cardiac arrest. Despite 80 min continous cardiopulmonary resuscitation the patient died. Elevated tryptase level in the patient’s blood sample taken before death confirmed anaphylactic reaction. On autopsy we confirmed the tuberculous etiology of generalized granulomatous inflammation.Conclusions: It is important to recognize anaphylactic reaction during anesthesia early and to take adequate measures in order to prevent unfavorable outcome. Tryptase assay of a blood sample taken during life or postmortem may help to identify anaphylactic reaction.

  7. Topics in heavy ion reactions

    International Nuclear Information System (INIS)

    Feshbach, H.

    1980-01-01

    Methods are discussed which, by straightforward extensions of currently available concepts and procedures, can be used for the description of reactions induced by heavy ions. The first section describes a nuclear Weiszaecker-Williams method for peripheral collisions of nuclei which is here extended to pion production in peripheral collisions. The second section emphasizes the relationship between the collision of an energetic proton and that of an energetic heavy ion with a nucleus. The comparatively remarkable behavior of the observed energy dependence of the angular distribution and average energy of the fragments produced in proton collision is described and a qualitative explanation offered. The third section is concerned with the'pre-equilibrium' reactions as well as the multi-step direct reactions which are known to play an important role in heavy ion collisions. A statistical theory of multi-step direct and multi-step compound reactions providing explicit expressions for the energy and angular distributions is formulated. A diffusion equation in momentum space is obtained as an approximation to these formulas. The extension of these results to heavy ion reactions in which phenomena involving deformation, mass and charge transfer and multi-particle final states are important, is made. (author)

  8. Combustion kinetics and reaction pathways

    Energy Technology Data Exchange (ETDEWEB)

    Klemm, R.B.; Sutherland, J.W. [Brookhaven National Laboratory, Upton, NY (United States)

    1993-12-01

    This project is focused on the fundamental chemistry of combustion. The overall objectives are to determine rate constants for elementary reactions and to elucidate the pathways of multichannel reactions. A multitechnique approach that features three independent experiments provides unique capabilities in performing reliable kinetic measurements over an exceptionally wide range in temperature, 300 to 2500 K. Recent kinetic work has focused on experimental studies and theoretical calculations of the methane dissociation system (CH{sub 4} + Ar {yields} CH{sub 3} + H + Ar and H + CH{sub 4} {yields} CH{sub 3} + H{sub 2}). Additionally, a discharge flow-photoionization mass spectrometer (DF-PIMS) experiment is used to determine branching fractions for multichannel reactions and to measure ionization thresholds of free radicals. Thus, these photoionization experiments generate data that are relevant to both reaction pathways studies (reaction dynamics) and fundamental thermochemical research. Two distinct advantages of performing PIMS with high intensity, tunable vacuum ultraviolet light at the National Synchrotron Light Source are high detection sensitivity and exceptional selectivity in monitoring radical species.

  9. Inorganic Reaction Mechanisms Part II: Homogeneous Catalysis

    Science.gov (United States)

    Cooke, D. O.

    1976-01-01

    Suggests several mechanisms for catalysis by metal ion complexes. Discusses the principal factors of importance in these catalysis reactions and suggests reactions suitable for laboratory study. (MLH)

  10. A unified diabatic description for electron transfer reactions, isomerization reactions, proton transfer reactions, and aromaticity.

    Science.gov (United States)

    Reimers, Jeffrey R; McKemmish, Laura K; McKenzie, Ross H; Hush, Noel S

    2015-10-14

    While diabatic approaches are ubiquitous for the understanding of electron-transfer reactions and have been mooted as being of general relevance, alternate applications have not been able to unify the same wide range of observed spectroscopic and kinetic properties. The cause of this is identified as the fundamentally different orbital configurations involved: charge-transfer phenomena involve typically either 1 or 3 electrons in two orbitals whereas most reactions are typically closed shell. As a result, two vibrationally coupled electronic states depict charge-transfer scenarios whereas three coupled states arise for closed-shell reactions of non-degenerate molecules and seven states for the reactions implicated in the aromaticity of benzene. Previous diabatic treatments of closed-shell processes have considered only two arbitrarily chosen states as being critical, mapping these states to those for electron transfer. We show that such effective two-state diabatic models are feasible but involve renormalized electronic coupling and vibrational coupling parameters, with this renormalization being property dependent. With this caveat, diabatic models are shown to provide excellent descriptions of the spectroscopy and kinetics of the ammonia inversion reaction, proton transfer in N2H7(+), and aromaticity in benzene. This allows for the development of a single simple theory that can semi-quantitatively describe all of these chemical phenomena, as well as of course electron-transfer reactions. It forms a basis for understanding many technologically relevant aspects of chemical reactions, condensed-matter physics, chemical quantum entanglement, nanotechnology, and natural or artificial solar energy capture and conversion.

  11. Redox reactions in food fermentations

    DEFF Research Database (Denmark)

    Hansen, Egon Bech

    2018-01-01

    Food fermentations are typically performed without actively supplying air. Except for possible surface microorganisms, oxygen will only be transiently available and the redox reactions during the fermentation need to be in balance. Production of ATP from fermentation of carbohydrates typically in...... of the redox properties of strains used to compose food cultures.......Food fermentations are typically performed without actively supplying air. Except for possible surface microorganisms, oxygen will only be transiently available and the redox reactions during the fermentation need to be in balance. Production of ATP from fermentation of carbohydrates typically...... involves oxidative steps in the early part of the pathways whereas a multitude of different reactions are used as compensating reductions. Much of the diversity seen between food fermentations arise from the different routes and the different electron acceptors used by microorganisms to counterbalance...

  12. Two Paired "Le Chatelier" Reactions

    Science.gov (United States)

    Cawley, John J.

    1995-07-01

    We have created a two-week, two hour-per-week cyclic experiment, which pairs two reactions. These reactions, the acid catalyzed esterification to yield n-amyl acetate and the base catalyzed hydrolysis of n-amyl acetate are intended to serve as a first and last experiment respectively, of the second-semester laboratory for liberal arts students. Because of time constraints, we have modified these experiments so that no distillation is performed as a purification step. The notion of achieving yields beyond the equilibrium value is discussed in terms of the pragmatics of removing one of the products of an equilibrium. Because of this "Le Chatelier" aspect of each reaction, each of them may be pushed in practicality to completion, which is well beyond the equilibrium value expectation. Because of the cycle, the chemistry may be done on a scale well beyond the microscale approach with little loss of material.

  13. Anaphylactic reactions to novel foods

    DEFF Research Database (Denmark)

    Ballardini, Natalia; Nopp, Anna; Hamsten, Carl

    2017-01-01

    Availability of "exotic" foods is steadily increasing. In this report, we describe the first case of anaphylaxis to crocodile meat. The patient was a 13-year-old boy with severe immunoglobulin E-mediated allergy to chicken meat. When tasting crocodile meat for the first time, he developed...... an anaphylactic reaction. Cross-reactivity between chicken and crocodile meat was suspected to have triggered this reaction. Basophil activation and immunoglobulin E testing confirmed the boy's allergic reaction to crocodile meat proteins. Molecular analysis identified a crocodile a-parvalbumin, with extensive...... sequence homology to chicken a-parvalbumin, as the main cross-reactive allergen. We conclude that crocodile meat can be a potent food allergen and patients with allergy to chicken meat should be advised to avoid intake of meat from crocodile species. Both foods and people travel around the world...

  14. Dynamic effects in fragmentation reactions

    International Nuclear Information System (INIS)

    Bertsch, G. F.; Esbensen, H.

    2002-01-01

    Fragmentation reactions offer a useful tool to study the spectroscopy of halo nuclei, but the large extent of the halo wave function makes the reaction theory more difficult. The simple reaction models based on the eikonal approximation for the nuclear interaction or first-order perturbation theory for the Coulomb interaction have systematic errors that they investigate here, comparing to the predictions of complete dynamical calculations. They find that stripping probabilities are underpredicted by the eikonal model, leading to extracted spectroscopy strengths that are two large. In contrast, the Coulomb excitation is overpredicted by the simple theory. They attribute this to a screening effect, as is well known in the Barkas effect on stopping powers. The errors decrease with beam energy as E(sub beam)(sup -1), and are not significant at beam energies above 50 MeV/u. At lower beam energies, the effects should be taken into account when extracting quantitative spectroscopic strengths

  15. Effective dynamics along given reaction coordinates, and reaction rate theory.

    Science.gov (United States)

    Zhang, Wei; Hartmann, Carsten; Schütte, Christof

    2016-12-22

    In molecular dynamics and related fields one considers dynamical descriptions of complex systems in full (atomic) detail. In order to reduce the overwhelming complexity of realistic systems (high dimension, large timescale spread, limited computational resources) the projection of the full dynamics onto some reaction coordinates is examined in order to extract statistical information like free energies or reaction rates. In this context, the effective dynamics that is induced by the full dynamics on the reaction coordinate space has attracted considerable attention in the literature. In this article, we contribute to this discussion: we first show that if we start with an ergodic diffusion process whose invariant measure is unique then these properties are inherited by the effective dynamics. Then, we give equations for the effective dynamics, discuss whether the dominant timescales and reaction rates inferred from the effective dynamics are accurate approximations of such quantities for the full dynamics, and compare our findings to results from approaches like Mori-Zwanzig, averaging, or homogenization. Finally, by discussing the algorithmic realization of the effective dynamics, we demonstrate that recent algorithmic techniques like the "equation-free" approach and the "heterogeneous multiscale method" can be seen as special cases of our approach.

  16. Miniaturized continuous flow reaction vessels: influence on chemical reactions

    NARCIS (Netherlands)

    Brivio, M.; Verboom, Willem; Reinhoudt, David

    2006-01-01

    This review offers an overview of the relatively young research area of continuous flow lab-on-a-chip for synthetic applications. A short introduction on the basic aspects of lab-on-a-chip is given in the first part. Subsequently, the effects of downscaling reaction vessels as well as the advantages

  17. Reaction rate of propene pyrolysis.

    Science.gov (United States)

    Han, Peipei; Su, Kehe; Liu, Yan; Wang, Yanli; Wang, Xin; Zeng, Qingfeng; Cheng, Laifei; Zhang, Litong

    2011-10-01

    The reaction rate of propene pyrolysis was investigated based on the elementary reactions proposed in Qu et al., J Comput Chem 2009, 31, 1421. The overall reaction rate was developed with the steady-state approximation and the rate constants of the elementary reactions were determined with the variational transition state theory. For the elementary reaction having transition state, the vibrational frequencies of the selected points along the minimum energy path were calculated with density functional theory at B3PW91/6-311G(d,p) level and the energies were improved with the accurate model chemistry method G3(MP2). For the elementary reaction without transition state, the frequencies were calculated with CASSCF/6-311G(d,p) and the energies were refined with the multireference configuration interaction method MRCISD/6-311G(d,p). The rate constants were evaluated within 200-2000 K and the fitted three-parameter expressions were obtained. The results are consistent with those in the literatures in most cases. For the overall rate, it was found that the logarithm of the rate and the reciprocal temperature have excellent linear relationship above 400 K, predicting that the rate follows a typical first-order law at high temperatures of 800-2000 K, which is also consistent with the experiments. The apparent activation energy in 800-2000 K is 317.3 kJ/mol from the potential energy surface of zero Kelvin. This value is comparable with the energy barriers, 365.4 and 403.7 kJ/mol, of the rate control steps. However, the apparent activation energy, 215.7 kJ/mol, developed with the Gibbs free energy surface at 1200 K is consistent with the most recent experimental result 201.9 ± 0.6 kJ/mol. Copyright © 2011 Wiley Periodicals, Inc.

  18. Clozapine-associated extrapyramidal reaction.

    Science.gov (United States)

    Elliott, E S; Marken, P A; Ruehter, V L

    2000-05-01

    To report a case of extrapyramidal reaction associated with a dosage increase of clozapine. A 44-year-old white man with a 20-year history of chronic paranoid schizophrenia was admitted to an inpatient psychiatric facility. His prior medications restarted on admission were clozapine 650 mg at bedtime, haloperidol 10 mg at bedtime, clonazepam 2 mg/d, and aspirin 325 mg/d. Two days after admission (hospital day 3), clozapine and clonazepam were discontinued, and he was prescribed haloperidol 5 mg every morning and 10 mg every evening. Stabilization occurred over the following 24 days, with progressively lower dosages of haloperidol and increasing dosages of clozapine. Haloperidol was discontinued on day 24. On day 47, the patient was agitated and making bizarre statements; thus, the morning dose of clozapine was increased by 50 mg (total 450 mg/d). On day 48 at 2200, a dystonic reaction was diagnosed; he received intramuscular diphenhydramine 50 mg, which caused the reaction to subside. At the time of the adverse reaction, he was prescribed clozapine 450 mg/d, vitamin E 400 IU three times daily, aspirin 325 mg/d, and acetaminophen, milk of magnesia, and Maalox as needed. Although the risk of extrapyramidal symptoms (EPS) is significantly lower with clozapine than with conventional agents, elevated clozapine blood concentrations have been reported to cause EPS; other reports have cited severe dystonias and dyskinesias on abrupt clozapine withdrawal. Considering the medications prescribed at the time and the discontinuation of haloperidol 24 days before the event, clozapine was the most likely cause of the extrapyramidal reaction. Regardless of anticipated safety associated with novel antipsychotics such as clozapine, reports of dystonic reactions must be taken into account and patients monitored appropriately.

  19. Allergic reactions occurring during anaesthesia.

    Science.gov (United States)

    Mertes, P M; Laxenaire, M C

    2002-04-01

    Anaphylactic reactions to anaesthetic and associated agents used during the perioperative period have been reported with increasing frequency in most developed countries. Any drug administered in the perioperative period can potentially produce life-threatening immune-mediated anaphylaxis. Most published reports on the incidence of anaphylaxis come from France, Australia, the UK and New Zealand. These reflect an active policy of systematic clinical and/or laboratory investigation of suspected immune-mediated reactions. The estimated incidence of anaphylaxis ranges from 1:10,000 to 1:20,000. Muscle relaxants (69.1%) and latex (12.1%) were the most frequently involved drugs according to the most recent French epidemiological survey. Clinical symptoms do not afford an easy distinction between immune-mediated anaphylactic reactions and anaphylactoid reactions resulting from direct non-specific histamine release. Moreover, when restricted to a single clinical symptom, anaphylaxis can easily be misdiagnosed. Pre- and postoperative investigation must be performed to confirm the nature of the reaction, the responsibility of the suspected drugs and to provide precise recommendations for future anaesthetic procedures. These include plasma histamine, tryptase and specific IgE concentration determination at the time of the reaction and at skin tests 6 weeks later. In addition, since no specific treatment has been shown reliably to prevent the occurrence of anaphylaxis, allergy assessment must be performed in all high-risk patients. Treatment of anaphylaxis is aimed at interrupting contact with the responsible antigen, inhibiting mediator production and release, and modulating the effects of released mediators. It must be initiated as quickly as possible and relies on widely accepted principles. Finally, the need for proper epidemiological studies and the relative complexity of allergy investigation should be underscored. They represent an incentive for further development of

  20. Internal friction in enzyme reactions.

    Science.gov (United States)

    Rauscher, Anna; Derényi, Imre; Gráf, László; Málnási-Csizmadia, András

    2013-01-01

    The empirical concept of internal friction was introduced 20 years ago. This review summarizes the results of experimental and theoretical studies that help to uncover the nature of internal friction. After the history of the concept, we describe the experimental challenges in measuring and interpreting internal friction based on the viscosity dependence of enzyme reactions. We also present speculations about the structural background of this viscosity dependence. Finally, some models about the relationship between the energy landscape and internal friction are outlined. Alternative concepts regarding the viscosity dependence of enzyme reactions are also discussed. Copyright © 2012 International Union of Biochemistry and Molecular Biology, Inc.

  1. Vision 2020. Reaction Engineering Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Klipstein, David H. [Reaction Design, San Diego, CA (United States); Robinson, Sharon [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2001-01-01

    The Reaction Engineering Roadmap is a part of an industry- wide effort to create a blueprint of the research and technology milestones that are necessary to achieve longterm industry goals. This report documents the results of a workshop focused on the research needs, technology barriers, and priorities of the chemical industry as they relate to reaction engineering viewed first by industrial use (basic chemicals; specialty chemicals; pharmaceuticals; and polymers) and then by technology segment (reactor system selection, design, and scale-up; chemical mechanism development and property estimation; dealing with catalysis; and new, nonstandard reactor types).

  2. Dynamics of traveling reaction pulses

    International Nuclear Information System (INIS)

    Dovzhenko, A. Yu.; Rumanov, E. N.

    2007-01-01

    The growth of activator losses is accompanied by the decay of a traveling reaction pulse. In a ring reactor, this propagation threshold is present simultaneously with a threshold related to the ring diameter. The results of numerical experiments with pulses of an exothermal reaction reveal the transition from pulse propagation to a homogeneous hot regime, established regimes with periodic variations of the pulse velocity, and oscillatory decay of the pulse. When the medium becomes 'bistable' as a result of the variation in parameters, this factor does not prevent the propagation of pulses, but leads to changes in the pulse structure

  3. Reaction

    African Journals Online (AJOL)

    raoul

    12 janv. 2012 ... Key words: Métastase, rate, colon, carcinome. Received: 28/12/2011 - Accepted: 09/01/2012 - Published: ... tomodensitométriques au moment du diagnostic du cancer primitif ou lors du suivi radiologique régulier des patients atteints de cancers. Le recours à la TEP-FDG couplée au scanner serait d'un ...

  4. Reaction

    African Journals Online (AJOL)

    abp

    19 oct. 2017 ... Axillary block is an easy and recommended technique in children. Its use in children with acute hepatitis A is not risk free especially when associated with sedation using remifentanil and propofol. Similarly, the presence of a single hydatid cyst allows general anesthesia with mono- pulmonary ventilation.

  5. Reaction

    African Journals Online (AJOL)

    abp

    2013-03-05

    Mar 5, 2013 ... define direct costs to include the out-of pocket (monetary) expenditures such as payments for ... elevated blood pressure is more of the late middle age and elderly group. It also suggests that at this age they ... definition, the study showed that about 53% of the household of the patients incurred catastrophic ...

  6. Palladium-Catalysed Coupling Reactions

    NARCIS (Netherlands)

    de Vries, Johannes G.; Beller, M; Blaser, HU

    2012-01-01

    Palladium-catalysed coupling reactions have gained importance as a tool for the production of pharmaceutical intermediates and to a lesser extent also for the production of agrochemicals, flavours and fragrances, and monomers for polymers. In this review only these cases are discussed where it seems

  7. The Pitfalls of Precipitation Reactions.

    Science.gov (United States)

    Slade, Peter W.; Rayner-Canham, Geoffrey W.

    1990-01-01

    Described are some of the difficulties presented in these reactions by competing equilibria that are usually ignored. Situations involving acid-base equilibria, solubility product calculations, the use of ammonia as a complexing agent, and semiquantitative comparisons of solubility product values are discussed. (CW)

  8. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    ... improvements in reactor performance. In this article, application of recent (and not so recent) developments in engineering reactors for catalytic reactions is discussed. Some examples where performance enhancement was realized by catalyst design, appropriate choice of reactor, better injection and dispersion strategies ...

  9. Apparent tunneling in chemical reactions

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Hansen, Flemming Yssing; Billing, G. D.

    2000-01-01

    A necessary condition for tunneling in a chemical reaction is that the probability of crossing a barrier is non-zero, when the energy of the reactants is below the potential energy of the barrier. Due to the non-classical nature (i.e, momentum uncertainty) of vibrational states this is, however...

  10. Reactions of ethanol on Ru

    NARCIS (Netherlands)

    Sturm, Jacobus Marinus; Liu, Feng; Lee, Christopher James; Bijkerk, Frederik

    2012-01-01

    The adsorption and reactions of ethanol on Ru(0001) were studied with temperatureprogrammed desorption (TPD) and reflection-absorption infrared spectroscopy (RAIRS). Ethanol was found to adsorb intact onto Ru(0001) below 100 K. Heating to 250 K resulted in formation of ethoxy groups, which undergo

  11. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    on selectivity can make substantial impact on process viability and economics. Extensive studies have been conducted to establish sound basis for design and engineering of reactors for practising such catalytic reactions and for realizing improvements in reactor performance. In this article, application of recent (and not so ...

  12. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    cation strategies for effective translation of laboratory process to practise. ... control). Several tools for modelling of chemical kinetics and reactions are already well-developed and routinely used in practice for facilitating engineering of reactors. Sev- eral excellent ... in absence of catalyst and is often controlled by mix-.

  13. Organic Reaction Mechanism Controversy: Pedagogical ...

    African Journals Online (AJOL)

    The paper investigated the pedagogical implications of the controversy generated by the nature of reaction mechanism in organic chemistry as to whether it can be proven or not. A conference of a chemist, chemical educator, a graduate chemistry teacher and a graduate assistant was organized. The conference lasted for ...

  14. Reaction rates when barriers fluctuate

    OpenAIRE

    Reimann, Peter

    1999-01-01

    Reaction rates when barriers fluctuate : a path integral approach / P. Hänggi and P. Reimann. - In: International Conference on Path Integrals from peV to TeV : Proceedings of the ... / eds.: R. Casalbuoni ... - Singapore u.a. : World Scientific, 1999. - S. 407-409

  15. Reduction of chemical reaction models

    Science.gov (United States)

    Frenklach, Michael

    1991-01-01

    An attempt is made to reconcile the different terminologies pertaining to reduction of chemical reaction models. The approaches considered include global modeling, response modeling, detailed reduction, chemical lumping, and statistical lumping. The advantages and drawbacks of each of these methods are pointed out.

  16. Reactants encapsulation and Maillard Reaction

    NARCIS (Netherlands)

    Troise, A.D.; Fogliano, V.

    2013-01-01

    In the last decades many efforts have been addressed to the control of Maillard Reaction products in different foods with the aim to promote the formation of compounds having the desired color and flavor and to reduce the concentration of several potential toxic molecules. Encapsulation, already

  17. Humanism and science: a reaction.

    Science.gov (United States)

    Wampold, Bruce E

    2012-12-01

    Authors in this section have noted that humanism is intrinsic to psychotherapy, although disagreements remain. One of the disagreements is about the role of science in humanism. In this reaction, I contend that humanism, as discussed in these articles, is a legitimate theory to be subjected to scientific scrutiny. (c) 2012 APA, all rights reserved.

  18. Immediate hypersensitivity reactions to corticosteroids.

    Science.gov (United States)

    Patel, Adesh; Bahna, Sami L

    2015-09-01

    To review the literature on immediate hypersensitivity reactions to corticosteroids and classify them according to manifestations, routes of exposure, causative preparations, diagnostic tests, and management. PubMed search for English-language publications from January 1, 2004 through December 31, 2014 using search terms corticosteroid, glucocorticoid, or steroid combined with hypersensitivity, allergy, or anaphylaxis. Only reports of immediate hypersensitivity reactions that occurred sooner than 24 hours after administration of a corticosteroid were included. Excluded were reports on patients with delayed reactions, including contact dermatitis. Forty-eight articles fulfilled the criteria, reporting 120 reactions in 106 patients 2 to 90 years of age (55 male and 51 female). The most commonly reported manifestation was anaphylaxis in 60.8% (73 of 120) followed by urticaria and/or angioedema in 26.7%. Exposure to corticosteroid was through any route, with intravenous being the most common (44.2%, 53 of 120), followed by oral in 25.8% and intra-articular in 11.7%. Methylprednisolone was the most commonly implicated (40.8%) followed by prednisolone (20.0%). Some reacted to more than 1 preparation. Pharmacologically-inactive ingredients were implicated in 28.3%. Diagnosis was based primarily on medical history and in most cases was confirmed by challenge testing. Skin tests were positive in 74.1%. The vast majority of patients tolerated at least 1 alternative preparation, and very rarely desensitization was required. Corticosteroids seem to be rare causes of immediate hypersensitivity reactions but possibly are misdiagnosed or under-reported relative to their worldwide use. Physicians should be cognizant of this entity and identify safe alternative preparations. Copyright © 2015 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  19. KINETICS AND MECHANISM OF REACTION OF ACIDIC ...

    African Journals Online (AJOL)

    For both Nile blue and Meldola\\'s blue reactions the rates have first-order dependence on each substrate, chlorite and acid. Both reactions showed negative salt effect indicating the reaction is between the oppositely charged species, likely the substrate cation and chlorite anion. The acidic chlorite reaction with MB+ was ...

  20. Use of Isotopes for Studying Reaction Mechanisms

    Indian Academy of Sciences (India)

    would help us optimize reaction conditions to effect higher yields, minimize reaction times, etc. The transformation ... effect of the isotope on the reaction rate. In the following. Uday Maitra and. J Chandrasekhar .... to the reaction, the rate of isotope exchange was unaltered, but the rate of racemization (of the reactant) became ...

  1. Reaction of hydrogen atoms with acrylaldehyde

    International Nuclear Information System (INIS)

    Koda, Seiichiro; Nakamura, Kazumoto; Hoshino, Takashi; Hikita, Tsutomu

    1978-01-01

    The reaction of hydrogen atoms with acrylaldehyde was investigated in a fast flow reactor equipped with a time-of-flight type mass spectrometer under reduced pressure. Main reaction products were carbon monoxide, ethylene, ethane, methane, and propanal. Consideration of the distributions of the reaction products under various reaction conditions showed that hydrogen atoms attacked the C=C double bond, especially its inner carbon side under reduced pressure. Resulting hot radicals caused subsequent reactions. The relative value of the apparent bimolecular rate constant of the reaction against that of trans-2-butene with hydrogen atoms was 1.6+-0.2, which supported the above-mentioned initial reaction. (auth.)

  2. Optimizing Chemical Reactions with Deep Reinforcement Learning.

    Science.gov (United States)

    Zhou, Zhenpeng; Li, Xiaocheng; Zare, Richard N

    2017-12-27

    Deep reinforcement learning was employed to optimize chemical reactions. Our model iteratively records the results of a chemical reaction and chooses new experimental conditions to improve the reaction outcome. This model outperformed a state-of-the-art blackbox optimization algorithm by using 71% fewer steps on both simulations and real reactions. Furthermore, we introduced an efficient exploration strategy by drawing the reaction conditions from certain probability distributions, which resulted in an improvement on regret from 0.062 to 0.039 compared with a deterministic policy. Combining the efficient exploration policy with accelerated microdroplet reactions, optimal reaction conditions were determined in 30 min for the four reactions considered, and a better understanding of the factors that control microdroplet reactions was reached. Moreover, our model showed a better performance after training on reactions with similar or even dissimilar underlying mechanisms, which demonstrates its learning ability.

  3. Resonance phenomena in few-body reactions

    International Nuclear Information System (INIS)

    Micek, S.

    1976-01-01

    In this work resonant states observed in two-body (p,p) reactions are compared. Theoretical analysis gives agreement in the resonant parameters in both types of the reactions for 41 Sc and 59 Cu nuclei. The excitation of states with higher angular momenta in the three-body reactions allows one to use this reaction as an supplementary to the two-body reaction in the investigations of resonant states. (author)

  4. Reaction engineering of urea alcoholysis: Alkyl carbamates

    OpenAIRE

    Mote, Dhananjay R.; Ranade, Vivek V.

    2017-01-01

    Urea alcoholysis is a reversible reaction generating alkyl carbamate and ammonia as products. The reaction can be performed non-catalytically or in presence of catalyst. The first step in Reaction engineering analysis is to finalize the reactor configuration. In this case it is important to determine the necessity of reactive separation (simultaneous reaction and separation). This has been addressed by first establishing the reversibility of the reaction through theoretical and experimental i...

  5. Thermodynamics of Enzyme-Catalyzed Reactions Database

    Science.gov (United States)

    SRD 74 Thermodynamics of Enzyme-Catalyzed Reactions Database (Web, free access)   The Thermodynamics of Enzyme-Catalyzed Reactions Database contains thermodynamic data on enzyme-catalyzed reactions that have been recently published in the Journal of Physical and Chemical Reference Data (JPCRD). For each reaction the following information is provided: the reference for the data, the reaction studied, the name of the enzyme used and its Enzyme Commission number, the method of measurement, the data and an evaluation thereof.

  6. Multiresponse modelling of the caramelisation reaction

    OpenAIRE

    Quintas, Mafalda; Guimarães, Carla; Baylina, João; Brandão, Teresa R. S.; Silva, Cristina L.M.

    2007-01-01

    Multiresponse modelling is a powerful tool for studying complex kinetics of reactions occurring in food products. This modelling technique uses information of reactants and products involved, allowing insightful kinetic parameters estimation and helping in clarifying reaction mechanisms. One example of a complex reaction that occurs in food processing is the caramelisation reaction. Caramelisation is the common name for a group of reactions observed when carbohydrates are exposed to high temp...

  7. Limits for Stochastic Reaction Networks

    DEFF Research Database (Denmark)

    Cappelletti, Daniele

    at a certain time are stochastically modelled by means of a continuous-time Markov chain. Our work concerns primarily stochastic reaction systems, and their asymptotic properties. In Paper I, we consider a reaction system with intermediate species, i.e. species that are produced and fast degraded along a path...... network tends to that of the original one. In particular, we prove a uniform punctual convergence in distribution and weak convergence of the integrals of continuous functions along the paths of the two models. Under some extra conditions, we also prove weak convergence of the two processes. The result....... Such species, in the deterministic modelling regime, assume always the same value at any positive steady state. In the stochastic setting, we prove that, if the initial condition is a point in the basin of attraction of a positive steady state of the corresponding deterministic model and tends to innity...

  8. MEANS FOR TERMINATING NUCLEAR REACTIONS

    Science.gov (United States)

    Cooper, C.M.

    1959-02-17

    An apparatus is presented for use in a reactor of the heterogeneous, fluid cooled type for the purpose of quickly terminating the reaction, the coolant being circulated through coolant tubes extending through the reactor core. Several of the tubes in the critical region are connected through valves to a tank containing a poisoning fluid having a high neutron capture crosssection and to a reservoir. When it is desired to quickly terminate the reaction, the valves are operated to permit the flow of the poisoning fluid through these particular tubes and into the reservoir while normal coolant is being circulated through the remaining tubes. The apparatus is designed to prevent contamination of the primary coolant by the poisoning fluid.

  9. Theoretical aspects of surface reactions

    Science.gov (United States)

    Nørskov, J. K.; Stoltze, P.

    1987-10-01

    A short review is given of our present understanding of the trends in the chemisorption energies and activation energies for dissociation of simple gas molecules on the transition metals. The effect of adsorbed alkali atoms on the activation energy for dissociation is also discussed. This is then used to explain the trends in activity along the transition metal rows and the promoting effect of K for the ammonia synthesis reaction. The basis for the description is the development of a kinetic model for the ammonia synthesis which can describe quantitatively the macroscopic kinetics of a commercial catalyst under industrial conditions. The model relates the reaction rate directly to the properties of the chemisorbed reactants, intermediates and product as measured for model single crystal systems under ultrahigh vacuum conditions.

  10. Electrochemical promotion of catalytic reactions

    Science.gov (United States)

    Imbihl, R.

    2010-05-01

    The electrochemical promotion of heterogeneously catalyzed reactions (EPOC) became feasible through the use of porous metal electrodes interfaced to a solid electrolyte. With the O 2- conducting yttrium stabilized zirconia (YSZ), the Na + conducting β″-Al 2O 3 (β-alumina), and several other types of solid electrolytes the EPOC effect has been demonstrated for about 100 reaction systems in studies conducted mainly in the mbar range. Surface science investigations showed that the physical basis for the EPOC effect lies in the electrochemically induced spillover of oxygen and alkali metal, respectively, onto the surface of the metal electrodes. For the catalytic promotion effect general concepts and mechanistic schemes were proposed but these concepts and schemes are largely speculative. Applying surface analytical tools to EPOC systems the proposed mechanistic schemes can be verified or invalidated. This report summarizes the progress which has been achieved in the mechanistic understanding of the EPOC effect.

  11. Allergic reactions in red tattoos

    DEFF Research Database (Denmark)

    Hutton Carlsen, K; Køcks, M; Sepehri, M

    2016-01-01

    AIM: The aim of this study was to assess the feasibility of Raman spectroscopy as a screening technique for chemical characterisation of tattoo pigments in pathologic reacting tattoos and tattoo ink stock products to depict unsafe pigments and metabolites of pigments. MATERIALS/METHODS: Twelve...... to be feasible for chemical analysis of red pigments in allergic reactions. Raman spectroscopy has a major potential for fingerprint screening of problematic tattoo pigments in situ in skin, ex vivo in skin biopsies and in tattoo ink stock products, thus, to eliminate unsafe ink products from markets....... dermatome shave biopsies from allergic reactions in red tattoos were analysed with Raman spectroscopy (A 785-nm 300 mW diode laser). These were referenced to samples of 10 different standard tattoo ink stock products, three of these identified as the culprit inks used by the tattooist and thus by history...

  12. Vanadocene reactions with hydroxy acids

    International Nuclear Information System (INIS)

    Latyaeva, V.N.; Lineva, A.N.; Zimina, S.V.; Ehllert, O.G.; Arsen'eva, T.I.

    1984-01-01

    To prepare a series of vanadium cyclopentadienylcarboxylates soluble in water, the vanadocene reactions with lactic, γ-oxybutyric-, salicylic,- gallic-, orotic-, and acetylsalicylic acids have been studied. To determine the influence of cyclopentadienyl groups, bound with a vanadium atom, on the physiological activity of the complexes formed, vanadium halides are made to react with lactic acid. Only the vanadocene reaction with orotic acid was conducted in an aqueous medium, other interactions were realized in the diethyl ether, toluene, T, H, P medium. The interaction of vanadocene and vanadium halides with lactic-, salicylic-, acetylsalicylic- and gallic acids was found to lead to the formation of water-soluble vanadium complexes of Cp 2 , VOCOR or CpV (OCOR) 2 type. The data on the produced compounds yield, their IR spectra, decomposition temperatures, solubility, effective magnetic moments are presented

  13. Statistical theory of breakup reactions

    Energy Technology Data Exchange (ETDEWEB)

    Bertulani, Carlos A., E-mail: carlos.bertulani@tamuc.edu [Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce, TX (United States); Descouvemont, Pierre, E-mail: pdesc@ulb.ac.be [Physique Nucleaire Theorique et Physique Mathematique, Universite Libre de Bruxelles (ULB), Brussels (Belgium); Hussein, Mahir S., E-mail: hussein@if.usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Estudos Avancados

    2014-07-01

    We propose an alternative for Coupled-Channels calculations with loosely bound exotic nuclei (CDCC), based on the the Random Matrix Model of the statistical theory of nuclear reactions. The coupled channels equations are divided into two sets. The first set, described by the CDCC, and the other set treated with RMT. The resulting theory is a Statistical CDCC (CDCC{sub s}), able in principle to take into account many pseudo channels. (author)

  14. Stickland reactions of dental plaque.

    Science.gov (United States)

    Curtis, M A; Kemp, C W; Robrish, S A; Bowen, W H

    1983-01-01

    Dental plaque samples from monkeys (Macaca fascicularis) were shown to contain proline reduction activity in coupled Stickland reactions with other amino acids and also with certain end products of bacterial glucose metabolism. The unusually high concentration of bound and free proline in the oral environment may be of importance in both the production of base and in the removal of acid from the tooth surface after dietary carbohydrate ingestion. PMID:6618673

  15. Anaphylactic reaction after artificial insemination.

    Science.gov (United States)

    Orta, Marta; Ordoqui, Elena; Aranzábal, Ascensión; Fernández, Cristina; Bartolomé, Borja; Sanz, Maria Luisa

    2003-04-01

    Bovine seroalbumin is known as an allergen for human beings, but reactions to it in an artificial insemination procedure are much rarer. We report a case of anaphylaxis after intrauterine insemination (IUI) in which sensitization to bovine serum albumin (BSA) is demonstrated. Report the allergy evaluation performed in a patient who suffered a severe reaction immediately after an IUI procedure. A 33-year-old woman was referred because of an anaphylactic reaction after a second trial of IUI. She developed pruritus, abdominal pain, nausea and vomiting, bronchospasm, and generalized urticaria. She had an atopic medical history of pollen allergy and sensitization to cat epithelium. She had never had trouble with minor surgery and she usually uses latex material. She had never received heterologous sera before. Her husband's semen for the IUI was processed in a standard fluid medium called upgraded INRA B 2 (Laboratoires CCD, Paris, France), which contains amino acids, lipids, vitamins, BSA, penicillin, and streptomycin in addition to inorganic salts. Skin prick tests with the medium and BSA 10 mg/mL were positive. In vitro studies demonstrated an immunoglobulin E binding protein of 60 to 65 kDa and mast cells and basophil activation (CD63 expression) against BSA contained in the medium. Cutaneous and challenge tests with penicillin and streptomycin were negative. We consider the BSA in the semen culture medium to be the factor which triggered the anaphylactic reaction. This case supports the authors who state that media free from heterologous proteins should be used for human application, especially on atopic patients, to avoid sensitization.

  16. When the chain reaction started

    International Nuclear Information System (INIS)

    1968-01-01

    It was 2 December 1942. Just as the band of distinguished scientists were waiting for the world's first chain reaction to start in the first atomic pile Enrico Fermi looked at his watch and said 'Gentlemen, time for lunch'. This incident was part of the first-hand story related to members of the Agency staff on 3 September this year by Professor Herbert L. Anderson of Chicago University, one of the team engaged in the project. (author)

  17. Tuberculin reaction and BCG scar

    DEFF Research Database (Denmark)

    Timmermann, Clara Amalie Gade; Biering-Sørensen, Sofie; Aaby, Peter

    2015-01-01

    rate ratio (MRR) comparing children with a BCG scar with those without was 0.42 (95% CI = 0.19; 0.93). There was a similar tendency for TST positivity: MRR = 0.47 (95% CI = 0.14; 1.54). For LBW children who had both a positive TST reaction and a scar, the MRR was 0.22 (95% CI = 0.05; 0.87). For NBW...

  18. Statistical theory of breakup reactions

    International Nuclear Information System (INIS)

    Bertulani, Carlos A.; Descouvemont, Pierre; Hussein, Mahir S.

    2014-01-01

    We propose an alternative for Coupled-Channels calculations with loosely bound exotic nuclei (CDCC), based on the the Random Matrix Model of the statistical theory of nuclear reactions. The coupled channels equations are divided into two sets. The first set, described by the CDCC, and the other set treated with RMT. The resulting theory is a Statistical CDCC (CDCC s ), able in principle to take into account many pseudo channels. (author)

  19. Anaphylactoid Reaction Against to Atropine

    Directory of Open Access Journals (Sweden)

    Melike Korkmaz Toker

    2014-08-01

    Full Text Available In this case report, the anaphylactoid reaction against to atropine had been reported in a 51 years old woman patient who had undertaken to total abdominal hystrectomy and bilateral salphingooferectomy surgery. At the end of the surgery, the anesthesia maintenance finished during the extubation procedure consequtively atropine had given intravenously 0,01 mg.kg-1 for preventing the neostigmine’s cholinergic effects. After the enjection of atropine tachycardia occured, nonpitting edema, maculopapular skin rash beginning from the periferal veins especially head and neck region spread out althrough the body observed. Anaphylactoid reaction developing like angioedema at the head and neck region threated the airway safety, therefore methylprednisolone 4 mg.kg-1, ranitidine 50 mg and feniramine maleat 1 mg.kg-1 intravenously administered. For safety of the airway the patient transferred to intensive care unit as intubated. After 24 hours follow up patient had clinically recovered and extubated. With our case report we try to emphasise the anaphylactoid reaction against to atropine and raise awareness of the anesthesiologists.

  20. Modulation of spermatozoon acrosome reaction

    Directory of Open Access Journals (Sweden)

    Pilar Vigil

    2011-01-01

    Full Text Available Spermatozoon acrosome reaction is an exocytotic event of the utmost importance for the development of mammalian fertilisation. Current evidence shows that the triggering of the acrosome reaction (AR could be regulated by the action of diverse compounds, namely, metabolites, neurotransmitters and hormones. The aim of the present review is to describe the modulating effects of several compounds that have been classified as inductors or inhibitors of acrosome reaction. Among AR inductors, it is necessary to mention progesterone, angiotensin II, atrial natriuretic peptide, cathecolamines, insulin, leptin, relaxin and other hormones. Regarding the inhibitors, oestradiol and epidermal growth factor are among the substances that retard AR. It is worth mentioning that gamma-aminobutyric acid, a neurotransmitter known to be an inhibitor in the central nervous system, has been shown to induce AR. The multiple hormones located in the fluids of the female reproductive tract are also likely to act as subtle regulators of AR, constituting a fundamental aspect for the development of successful fertilisation. Finally, it is necessary to emphasise that the study of regulation exerted by hormones and other compounds on AR is essential for further understanding of mammalian reproductive biology, especially spermatozoon physiology.

  1. Microfabricated electrochemiluminescence cell for chemical reaction detection

    Science.gov (United States)

    Northrup, M. Allen; Hsueh, Yun-Tai; Smith, Rosemary L.

    2003-01-01

    A detector cell for a silicon-based or non-silicon-based sleeve type chemical reaction chamber that combines heaters, such as doped polysilicon for heating, and bulk silicon for convection cooling. The detector cell is an electrochemiluminescence cell constructed of layers of silicon with a cover layer of glass, with spaced electrodes located intermediate various layers forming the cell. The cell includes a cavity formed therein and fluid inlets for directing reaction fluid therein. The reaction chamber and detector cell may be utilized in any chemical reaction system for synthesis or processing of organic, inorganic, or biochemical reactions, such as the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction, which are examples of a synthetic, thermal-cycling-based reaction. The ECL cell may also be used in synthesis instruments, particularly those for DNA amplification and synthesis.

  2. Chlorination of Amino Acids: Reaction Pathways and Reaction Rates.

    Science.gov (United States)

    How, Zuo Tong; Linge, Kathryn L; Busetti, Francesco; Joll, Cynthia A

    2017-05-02

    Chlorination of amino acids can result in the formation of organic monochloramines or organic dichloramines, depending on the chlorine to amino acid ratio (Cl:AA). After formation, organic chloramines degrade into aldehydes, nitriles and N-chloraldimines. In this paper, the formation of organic chloramines from chlorination of lysine, tyrosine and valine were investigated. Chlorination of tyrosine and lysine demonstrated that the presence of a reactive secondary group can increase the Cl:AA ratio required for the formation of N,N-dichloramines, and potentially alter the reaction pathways between chlorine and amino acids, resulting in the formation of unexpected byproducts. In a detailed investigation, we report rate constants for all reactions in the chlorination of valine, for the first time, using experimental results and modeling. At Cl:AA = 2.8, the chlorine was found to first react quickly with valine (5.4 × 10 4 M -1 s -1 ) to form N-monochlorovaline, with a slower subsequent reaction with N-monochlorovaline to form N,N-dichlorovaline (4.9 × 10 2 M -1 s -1 ), although some N-monochlorovaline degraded into isobutyraldehyde (1.0 × 10 -4 s -1 ). The N,N-dichlorovaline then competitively degraded into isobutyronitrile (1.3 × 10 -4 s -1 ) and N-chloroisobutyraldimine (1.2 × 10 -4 s -1 ). In conventional drinking water disinfection, N-chloroisobutyraldimine can potentially be formed in concentrations higher than its odor threshold concentration, resulting in aesthetic challenges and an unknown health risk.

  3. Computer-aided design and construction of an antineutrino detector

    International Nuclear Information System (INIS)

    Stutz, A.

    1989-01-01

    The Bugey group is setting-up a new detector for another neutrino oscillation experiment. This thesis reports on the different steps concerning its realisation. Light yield, light transmission and pulse shape discrimination properties of NE 320 a new liquid scintillator loaded with 0.15% of Lithium 6 allow to realise a large volume detector (3 x 600 l) with an order of magnitude increase in sensitivity. The benefit of the neutron capture on Lithium 6 has been conserved owing to the segmentation of the whole detector volume in 98 cells and to energy resolution and pulse shape discrimination properties of the liquid. The efficiency is expected to be 0.5 and the essential component of the background is the natural activity of the scintillator. This makes this detector the most performant for neutrino oscillation experiment at reactor [fr

  4. Neutrino-antineutrino asymmetry around rotating black holes

    Indian Academy of Sciences (India)

    . = . The Latin and Greek alphabets indicate the flat and curved space coordinate respectively and we would work in units = = B = 1 and signature as (+ - --). Expanding (1), we get the Dirac Lagrangian separated into free and (gravita-.

  5. Cross sections for neutrino and antineutrino neutral current interactions

    International Nuclear Information System (INIS)

    Bosetti, P.C.; Deden, H.; Deutschmann, M.; Fritze, P.; Graessler, H.; Hasert, F.J.; Morfin, J.; Schulte, R.; Schultze, K.; Seyfert, H.; Banerjee, S.; Barnham, K.W.J.; Beuselinck, R.; Butterworth, I.; Clayton, E.F.; Miller, D.B.; Powell, K.J.; Davis, C.L.; Grossman, P.; McGow, R.; Mulvey, J.H.; Myatt, G.; Perkins, D.H.; Pons, R.; Radojicic, O.; Renton, P.; Saitta, B.; Stenger, V.

    1978-01-01

    The cross sections for γ and anti γ neutral current interactions for which the hadron energy is > 15 GeV have been measured. These results, and the ratios of neutral current to charged current sections, are in agreement with the Weinberg-Salam model. Values of sin 2 thetasub(w) have been obtained both with and without the use of a parametrisation for the hadronic part of the interaction; the values are in good agreement with each other and the preferred result, that obtained by the method independent of hadronic models, is sin 2 thetasub(w) = 0.22 +- 0.05. (Auth.)

  6. Neutrino-antineutrino asymmetry around rotating black holes

    Indian Academy of Sciences (India)

    important effects and hence can be constrained by Big Bang nucleosynthesis and power spectrum of cosmic microwave background, it becomes an important issue by itself to study new mechanisms which can generate neutrino asymmetry specially in the present epoch. When Dirac neutrinos propagate in gravitational ...

  7. Recent Developments in Neutrino/Antineutrino-Nucleus Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Morfín, Jorge G.; Nieves, Juan; Sobczyk, Jan T.

    2012-01-01

    Recent experimental results and developments in the theoretical treatment of neutrino-nucleus interactions in the energy range of 1–10 GeV are discussed. Difficulties in extracting neutrino-nucleon cross sections from neutrino-nucleus scattering data are explained and significance of understanding nuclear effects for neutrino oscillation experiments is stressed. Detailed discussions of the status of two-body current contribution in the kinematic region dominated by quasielastic scattering and specific features of partonic nuclear effects in weak DIS scattering are presented.

  8. Data acquisition system for segmented reactor antineutrino detector

    Czech Academy of Sciences Publication Activity Database

    Hons, Zdeněk; Vlášek, J.

    2017-01-01

    Roč. 12, č. 1 (2017), č. článku P01022. ISSN 1748-0221 R&D Projects: GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : Data acquisition concepts * Detector control systems (detector and experiment monitoring and slow-control system, architecture , hardware, algorithms, databases) * Neutrino detectors Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 1.220, year: 2016

  9. Chemical reactions in solvents and melts

    CERN Document Server

    Charlot, G

    1969-01-01

    Chemical Reactions in Solvents and Melts discusses the use of organic and inorganic compounds as well as of melts as solvents. This book examines the applications in organic and inorganic chemistry as well as in electrochemistry. Organized into two parts encompassing 15 chapters, this book begins with an overview of the general properties and the different types of reactions, including acid-base reactions, complex formation reactions, and oxidation-reduction reactions. This text then describes the properties of inert and active solvents. Other chapters consider the proton transfer reactions in

  10. [Reactions to insect stings and bites].

    Science.gov (United States)

    Ljubojević, Suzana; Lipozencić, Jasna

    2011-01-01

    Reaction to insect sting and bite may be local, such as erythema, edema and pruritus, or systemic, such as anaphylactic reaction. Diagnosis can be made by patient history, clinical picture, skin testing, total and specific IgE level, and provocation test. Local reactions are treated with cold compresses, topical corticosteroids and oral antihistamines. Oral and intramuscular antihistamines and corticosteroids are used for the treatment of mild systemic reactions, and in severe reaction epinephrine injections are added. Hyposensitization is indicated in patients with severe systemic reaction, positive skin tests and high level of specific IgE antibodies.

  11. Metal-catalyzed asymmetric aldol reactions

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Luiz C.; Lucca Junior, Emilio C. de; Ferreira, Marco A. B.; Polo, Ellen C., E-mail: ldias@iqm.unicamp.br [Universidade de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica

    2012-12-15

    The aldol reaction is one of the most powerful and versatile methods for the construction of C-C bonds. Traditionally, this reaction was developed in a stoichiometric version; however, great efforts in the development of chiral catalysts for aldol reactions were performed in recent years. Thus, in this review article, the development of metal-mediated chiral catalysts in Mukaiyama-type aldol reaction, reductive aldol reaction and direct aldol reaction are discussed. Moreover, the application of these catalysts in the total synthesis of complex molecules is discussed. (author)

  12. Substrate-Directed Catalytic Selective Chemical Reactions.

    Science.gov (United States)

    Sawano, Takahiro; Yamamoto, Hisashi

    2018-03-06

    The development of highly efficient reactions at only the desired position is one of the most important subjects in organic chemistry. Most of the reactions in current organic chemistry are reagent- or catalyst-controlled reactions, and the regio- and stereoselectivity of the reactions are determined by the inherent nature of the reagent or catalyst. In sharp contrast, substrate-directed reaction determines the selectivity of the reactions by the functional group on the substrate and can strictly distinguish sterically and electronically similar multiple reaction sites in the substrate. In this Perspective, three topics of substrate-directed reaction are mainly reviewed: (1) directing group-assisted epoxidation of alkenes, (2) ring-opening reactions of epoxides by various nucleophiles, and (3) catalytic peptide synthesis. Our newly developed synthetic methods with new ligands including hydroxamic acid derived ligands realized not only highly efficient reactions but also pinpointed reactions at the expected position, demonstrating the substrate-directed reaction as a powerful method to achieve the desired regio- and stereoselective functionalization of molecules from different viewpoints of reagent- or catalyst-controlled reactions.

  13. Microfabricated sleeve devices for chemical reactions

    Science.gov (United States)

    Northrup, M. Allen

    2003-01-01

    A silicon-based sleeve type chemical reaction chamber that combines heaters, such as doped polysilicon for heating, and bulk silicon for convection cooling. The reaction chamber combines a critical ratio of silicon and non-silicon based materials to provide the thermal properties desired. For example, the chamber may combine a critical ratio of silicon and silicon nitride to the volume of material to be heated (e.g., a liquid) in order to provide uniform heating, yet low power requirements. The reaction chamber will also allow the introduction of a secondary tube (e.g., plastic) into the reaction sleeve that contains the reaction mixture thereby alleviating any potential materials incompatibility issues. The reaction chamber may be utilized in any chemical reaction system for synthesis or processing of organic, inorganic, or biochemical reactions, such as the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction, which are examples of a synthetic, thermal-cycling-based reaction. The reaction chamber may also be used in synthesis instruments, particularly those for DNA amplification and synthesis.

  14. Department of Nuclear Reactions: Overview

    International Nuclear Information System (INIS)

    Rusek, K.

    2000-01-01

    Full text: During last year the physicists of the Department of Nuclear Reactions were involved in many experiments and projects: -Low energy nuclear reactions: For the first time a heavy ion beam from the Warsaw Cyclotron C-200 was used to investigate elastic and inelastic scattering of 12 C ions from 12 C target. The experiment is a part of a long range programme devoted to study the energy dependence of the nucleus-nucleus interactions. -Multifragmentation of relativistic heavy ions: Multifragmentation reactions induced by 12 C on different heavy targets and at different energies were studied in experiments performed at Gesellschaft fuer Schwerionenforschung by the ALADIN Collaboration. These asymmetric systems were investigated in order to study the interplay between preequilibrium and equilibrium phenomena in the nuclear liquid - gas phase transition. -The structure of nucleons: A novel, two-structure description of the Roper resonance was proposed on the basis of the α-p scattering data reanalysed by means of a T-matrix formalism. -Atomic physics: Emission of the X-rays by fast heavy ions (S, Ti, Fe) as they traverse the matter (thin carbon or other light element foil) was investigated in a series of experiments performed at University of Erlangen. It was demonstrated, that the characteristic K α X-rays emitted by a heavy ion can serve as a tool for Z-value control of the ion. -Material research: Semiconductor heterostructures were investigated by means of Rutherford Back Scattering and Channeling methods using the 2 MeV α particles from the Van de Graaff accelerator ''Lech'' at the Department. The following reports present the results and major successes which were achieved in 1999. (author)

  15. Neutral currents in semileptonic reactions

    International Nuclear Information System (INIS)

    Paschos, E.A.

    1975-05-01

    The evidence for weak neutral currents is analyzed in semileptonic reactions with special emphasis on their Lorentz and internal symmetry structure. It is found that present observations are consistent with the expectations of gauge theories, but other possibilities can not be ruled out. Of particular interest in this respect is the presence of a large isoscalar component. The excitation of the Δ-resonance by neutral currents is analyzed, and pion-nucleon mass distributions are presented. Charge asymmetries sensitive to isoscalar-isovector interferences are discussed. (U.S.)

  16. The first nuclear chain reaction

    International Nuclear Information System (INIS)

    Zinn, W.H.

    1989-01-01

    The author offers his recollections of the experimental efforts beginning in 1939 which culminated in the Chain Reaction in the squash court on December 2, 1942. Recalled are Columbia University experiments which did much to establish the feasibility of the chain in natural uranium and which stimulated the creation of the Manhattan District. The Columbia group moved to the University of Chicago, where, in early summer of 1942, construction and analysis of a number of subcritical reactors (piles) gave assurance with a high probability that only a reasonable amount of uranium and moderator would be required

  17. Giant resonances: reaction theory approach

    International Nuclear Information System (INIS)

    Toledo Piza, A.F.R. de; Foglia, G.A.

    1989-09-01

    The study of giant resonances through the use of reaction theory approach is presented and discussed. Measurements of cross-sections to the many available decay channels following excitation of giant multipole resonances (GMR) led one to view these phenomena as complicated dynamical syndromes so that theoretical requirements for their study must be extended beyond the traditional bounds of nuclear structure models. The spectra of decay products following GMR excitation in heavy nuclei are well described by statistical model (Hauser-Feshback, HF) predictions indicated that spreading of the collective modes plays a major role in shaping exclusive cross-sections. (A.C.A.S.) [pt

  18. Kinetics of heterogeneous catalytic reactions

    CERN Document Server

    Boudart, Michel

    2014-01-01

    This book is a critical account of the principles of the kinetics of heterogeneous catalytic reactions in the light of recent developments in surface science and catalysis science. Originally published in 1984. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase acc

  19. Department of Nuclear Reactions: Overview

    International Nuclear Information System (INIS)

    Rusek, K.

    2002-01-01

    Full text: Department of Nuclear Reactions has had a very productive year. We have carried out our work in close collaborations with physicists from many laboratories, home and foreign. The following reports cover three major domains of our activities: nuclear, material and atomic physics. * Nuclear physics: In collaboration with scientists from Ukraine experimental studies of nuclear reaction induced by heavy ions from the Warsaw Cyclotron have been performed. The aim of the experiments is to study nuclear reactions leading to the exotic light nuclei in exit channels and energy dependence of the nucleus - nucleus interactions. Proton induced charge-exchange reactions were investigated theoretically by means of multistep-direct model. Good agreement with the experimental data was achieved. A novel approach to the problem of the nuclear liquid → gas phase transition was proposed, based on synergetics - a domain of science dealing with self-organization in macroscopic systems. Decay properties of the Roper resonance were studied. Final analysis of the analysing powers for the polarized deuterons scattered on protons was accomplished. Experimental programme of the near-threshold meson production in proton - proton scattering has been started in collaboration with Forschungszentrum. Juelich. * Atomic physics: Spectra of the X-rays emitted by energetic sulphur ions scattered off carbon atoms were analysed in order to study the role of the multiple charge states of the inner shells in the dynamics of the collision process. Ionization probabilities in collision of oxygen ions with gold atoms were measured. The observed disagreement of the experimental data with the theoretical predictions suggest a strong effect generated by the sub-shell couplings. * Materials research: Ion channelling method was applied to investigate transformation of the defects in Al x Ga 1-x As crystalline layers. Activities of our colleagues in didactics have grown considerably. Lectures

  20. Anaphylactic reaction to intravenous cefazolin.

    Science.gov (United States)

    Faulk, D; Rodosevich, K; Katz, R L; Calmes, S H

    1993-12-01

    Allergic responses to cefazolin occur in approximately 3% to 5% of patients. The responsibility of the health care professional includes developing an awareness that histamine release in varying degrees can occur with the administration of a variety of drugs utilized throughout the perioperative period. The authors discuss the cardiopulmonary manifestations resulting from the release of histamine during an allergic reaction. Differentiation of diagnosis of the causative agent, the effective treatment of the anaphylactic response during anesthesia, and preventive measures to reduce anesthesia morbidity are examined.

  1. Dibaryon resonances in photon induced reactions

    International Nuclear Information System (INIS)

    Schwille, W.J.

    1981-11-01

    The author gives a review about the production of dibaryon resonances in photon reactions on deuterium targets. Especially he considers the reactions γ + d → p + n, γ + d → p + X, and γ + d → p + N + π. (HSI)

  2. Catalyst Initiation in the Oscillatory Carbonylation Reaction

    Directory of Open Access Journals (Sweden)

    Katarina Novakovic

    2011-01-01

    Full Text Available Palladium(II iodide is used as a catalyst in the phenylacetylene oxidative carbonylation reaction that has demonstrated oscillatory behaviour in both pH and heat of reaction. In an attempt to extract the reaction network responsible for the oscillatory nature of this reaction, the system was divided into smaller parts and they were studied. This paper focuses on understanding the reaction network responsible for the initial reactions of palladium(II iodide within this oscillatory reaction. The species researched include methanol, palladium(II iodide, potassium iodide, and carbon monoxide. Several chemical reactions were considered and applied in a modelling study. The study revealed the significant role played by traces of water contained in the standard HPLC grade methanol used.

  3. Organic chemistry - Fast reactions 'on water'

    NARCIS (Netherlands)

    Klijn, JE; Engberts, JBFN

    2005-01-01

    Efficient reactions in aqueous organic chemistry do not require soluble reactants, as had been thought. A newly developed ‘on-water’ protocol is characterized by short reaction times, and the products are easy to isolate.

  4. Amazing variational approach to chemical reactions

    OpenAIRE

    Fernández, Francisco M.

    2009-01-01

    In this letter we analyse an amazing variational approach to chemical reactions. Our results clearly show that the variational expressions are unsuitable for the analysis of empirical data obtained from chemical reactions.

  5. The mechanism of the modified Ullmann reaction

    NARCIS (Netherlands)

    Sperotto, Elena; Klink, Gerard P.M. van; Koten, Gerard van; Vries, Johannes G. de

    2010-01-01

    The copper-mediated aromatic nucleophilic substitution reactions developed by Fritz Ullmann and Irma Goldberg required stoichiometric amounts of copper and very high reaction temperatures. Recently, it was found that addition of relatively cheap ligands (diamines, aminoalcohols, diketones, diols)

  6. Scattering and transfer reactions with heavy ions

    International Nuclear Information System (INIS)

    Hussein, M.S.

    From the elastic scattering analysis the input parameters are found for the inelastic scattering analysis and the transfer reactions of the heavy ion reactions. The main theme reported is the likeness and conection among these processes. (L.C.) [pt

  7. Competing reaction channels in IR-laser-induced unimolecular reactions

    International Nuclear Information System (INIS)

    Berman, M.R.

    1981-01-01

    The competing reaction channels in the unimolecular decomposition of two molecules, formaldehyde and tetralin were studied. A TEA CO 2 laser was used as the excitation source in all experiments. The dissociation of D 2 CO was studied by infrared multiphoton dissociation (MPD) and the small-molecule nature of formaldehyde with regard to MPD was explored. The effect of collisions in MPD were probed by the pressure dependence of the MPD yield and ir fluorescence from multiphoton excited D 2 CO. MPD yield shows a near cubic dependence in pure D 2 CO which is reduced to a 1.7 power dependence when 15 torr of NO is added. The peak amplitude of 5 μm ir fluorescence from D 2 CO is proportional to the square of the D 2 CO pressure in pure D 2 CO or in the presence of 50 torr of Ar. Results are explained in terms of bottlenecks to excitation at the v = 1 level which are overcome by a combination of vibrational energy transfer and rotational relaxation. The radical/molecule branching ratio in D 2 CO MPD was 0.10 +- 0.02 at a fluence of 125 J/cm 2 at 946.0 cm -1 . The barrier height to molecular dissociation was calculated to be 3.6 +- 2.0 kcal/mole below the radical threshold or 85.0 +- 3.0 kcal/mole above the ground state of D 2 CO. In H 2 CO, this corresponds to 2.5 +- 2.0 kcal/mole below the radical threshold or 83.8 +- 3.0 kcal/mole above the ground state. Comparison with uv data indicate that RRKM theory is an acceptable description of formaldehyde dissociation in the 5 to 10 torr pressure range. The unimolecular decomposition of tetralin was studied by MPD and SiF 4 - sensitized pyrolysis. Both techniques induce decomposition without the interference of catalytic surfaces. Ethylene loss is identified as the lowest energy reaction channel. Dehydrogenation is found to result from step-wise H atom loss. Isomerization via disproportionation is also identified as a primary reaction channel

  8. Catalysis of Nuclear Reactions by Electrons

    Science.gov (United States)

    Lipoglavšek, Matej

    2018-01-01

    Electron screening enhances nuclear reaction cross sections at low energies. We studied the nuclear reaction 1H(19F,αγ)16O in inverse kinematics in different solid hydrogen targets. Measured resonance strengths differed by up to a factor of 10 in different targets. We also studied the 2H(p,γ)3He fusion reaction and observed electrons emitted as reaction products instead of γ rays. In this case electron screening greatly enhances internal conversion probability.

  9. Nuclear reaction rates and the primordial nucleosynthesis

    OpenAIRE

    Mishra, Abhishek; Basu, D. N.

    2011-01-01

    The theoretical predictions of the primordial abundances of elements in the big-bang nucleosynthesis (BBN) are dominated by uncertainties in the input nuclear reaction rates. We investigate the effect of modifying these reaction rates on light element abundance yields in BBN by replacing the thirty-five reaction rates out of the existing eighty-eight. We have studied these yields as functions of evolution time or temperature. We find that using these new reaction rates results in only a littl...

  10. Catalysis of Nuclear Reactions by Electrons

    Directory of Open Access Journals (Sweden)

    Lipoglavšek Matej

    2017-01-01

    Full Text Available Electron screening enhances nuclear reaction cross sections at low energies. We studied the nuclear reaction 1H(19F,αγ16O in inverse kinematics in different solid hydrogen targets. Measured resonance strengths differed by up to a factor of 10 in different targets. We also studied the 2H(p,γ3He fusion reaction and observed electrons emitted as reaction products instead of γ rays. In this case electron screening greatly enhances internal conversion probability.

  11. The Reaction of Oxy Hemoglobin with Nitrite

    DEFF Research Database (Denmark)

    Hathazi, Denisa; Scurtu, Florina; Bischin, Cristina

    2018-01-01

    -peroxynitrate. Density functional theory (DFT) calculations support this latter assignment. The reaction allows for differentiating between the reactivities of various chemically modified hemoglobins, including candidates for blood substitutes. Polymerization of hemoglobin slows the nitrite-induced oxidation, in sharp...... contrast to oxidative-stress type reactions which are generally accelerated, not inhibited. Sheep hemoglobin is found to be distinctly more resistant to reaction with nitrite compared to bovine Hb, at large nitrite concentrations (stopped-flow experiments directly observing the oxy + nitrite reaction...

  12. Multi-step direct reactions

    International Nuclear Information System (INIS)

    Koning, A.J.

    1992-07-01

    In recent years a variety of statistical theories has been developed concerning multistep direct (MSD) nuclear reactions. In addition, dominant in applications is a whole class of semiclassical models that may be subsumed under the heading of 'generalized exciton models'; these are basically MSD-type extensions on top of compound-like concepts. In this report the relation between their underlying statistical MSD-postulates are highlighted. A command framework is sketched that enables to generate the various MSD theories through assigning statistical properties to different parts of the nuclear Hamiltonian. Then it is shown that distinct forms of nuclear randomness are embodied in the mentioned theories. All these theories appear to be very similar at a qualitative level. In order to explain the high energy-tails and forward-peaked angular distribution typical for particles emitted in MSD reactions, it is imagined that the incident continuum particle stepwise looses its energy and direction in a sequence of collisions, thereby creating new particle-hole pairs in the target system. At each step emission may take place. The statistical aspect comes in because many continuum states are involved in the process. These are supposed to display chaotic behavior, the associated randomness assumption giving rise to important simplifications in the expression for MSD emission cross sections. This picture suggests that mentioned MSD models can be interpreted as a variant of essentially one and the same theory. 113 refs.; 25 figs.; 9 tabs

  13. Enantioselective solvent-free Robinson annulation reactions

    Indian Academy of Sciences (India)

    Unknown

    The use of proline or any other amino acid in asymmetric annulation reactions in a solid–liquid phase reaction in the absence of solvents to effect an asymmetric synthesis is an important step forward towards cleaner synthesis 2. ... Reports on solvent-free reactions have become increasingly frequent and the field has.

  14. Infrared laser-induced chemical reactions

    International Nuclear Information System (INIS)

    Katayama, Mikio

    1978-01-01

    The experimental means which clearly distinguishes between infrared ray-induced reactions and thermal reactions has been furnished for the first time when an intense monochromatic light source has been obtained by the development of infrared laser. Consequently, infrared laser-induced chemical reactions have started to develop as one field of chemical reaction researches. Researches of laser-induced chemical reactions have become new means for the researches of chemical reactions since they were highlighted as a new promising technique for isotope separation. Specifically, since the success has been reported in 235 U separation using laser in 1974, comparison of this method with conventional separation techniques from the economic point of view has been conducted, and it was estimated by some people that the laser isotope separation is cheaper. This report briefly describes on the excitation of oscillation and reaction rate, and introduces the chemical reactions induced by CW laser and TEA CO 2 laser. Dependence of reaction yield on laser power, measurement of the absorbed quantity of infrared ray and excitation mechanism are explained. Next, isomerizing reactions are reported, and finally, isotope separation is explained. It was found that infrared laser-induced chemical reactions have the selectivity for isotopes. Since it is evident that there are many examples different from thermal and photo-chemical reactions, future collection of the data is expected. (Wakatsuki, Y.)

  15. Reaction-Map of Organic Chemistry

    Science.gov (United States)

    Murov, Steven

    2007-01-01

    The Reaction-Map of Organic Chemistry lists all the most commonly studied reactions in organic chemistry on one page. The discussed Reaction-Map will act as another learning aide for the students, making the study of organic chemistry much easier.

  16. Reaction Order Ambiguity in Integrated Rate Plots

    Science.gov (United States)

    Lee, Joe

    2008-01-01

    Integrated rate plots are frequently used in reaction kinetics to determine orders of reactions. It is often emphasised, when using this methodology in practice, that it is necessary to monitor the reaction to a substantial fraction of completion for these plots to yield unambiguous orders. The present article gives a theoretical and statistical…

  17. Allergic reactions seen in orthodontic treatment

    Directory of Open Access Journals (Sweden)

    Hande Görücü Coşkuner

    2016-01-01

    Full Text Available Allergy can be defined as inappropriate and harmful response to harmless and ordinary materials. Allergic reactions, like in other fields of dentistry, can also be seen in the field of orthodontics. The reactions that occur against orthodontic materials can be seen as irritant or hypersensitivity reactions. The main reason of the irritant reactions is friction between soft tissues and orthodontic appliances. However, the reason of the hypersensitivity reactions is usually the antigenicity of the materials. Hypersensitivity reactions are usually seen as allergic contact dermatitis on face and neck; the occurrence of mucosal-gingival reactions and dermal and systemic reactions are rare. Latex, metal and acrylic resins are the most common allergens in orthodontics. Apart from these materials, allergic reactions can occur against bonding materials, extraoral appliances, disinfectants and antimicrobial agents. The reactions that occur against extraoral appliances usually result from metallic and elastic parts of the appliances or the appliance parts that are in contact with skin. Orthodontists should be aware of the allergic reactions to protect their patients’ health. The aim of this review was to evaluate the allergic reactions seen in orthodontic patients and discuss the cautions that orthodontists can take.

  18. Modelling Students' Visualisation of Chemical Reaction

    Science.gov (United States)

    Cheng, Maurice M. W.; Gilbert, John K.

    2017-01-01

    This paper proposes a model-based notion of "submicro representations of chemical reactions". Based on three structural models of matter (the simple particle model, the atomic model and the free electron model of metals), we suggest there are two major models of reaction in school chemistry curricula: (a) reactions that are simple…

  19. Method of controlling fusion reaction rates

    Science.gov (United States)

    Kulsrud, Russell M.; Furth, Harold P.; Valeo, Ernest J.; Goldhaber, Maurice

    1988-01-01

    A method of controlling the reaction rates of the fuel atoms in a fusion reactor comprises the step of polarizing the nuclei of the fuel atoms in a particular direction relative to the plasma confining magnetic field. Fusion reaction rates can be increased or decreased, and the direction of emission of the reaction products can be controlled, depending on the choice of polarization direction.

  20. Parental Reactions to Cleft Palate Children.

    Science.gov (United States)

    Vanpoelvoorde, Leah

    This literature review examines parental reactions following the birth of a cleft lip/palate child, focusing primarily on the mother's reactions. The research studies cited have explored such influences on maternal reactions as her feelings of lack of control over external forces and her feelings of guilt that the deformity was her fault. Delays…

  1. The Rate Laws for Reversible Reactions.

    Science.gov (United States)

    King, Edward L.

    1986-01-01

    Provides background information for teachers on the rate laws for reversible reactions. Indicates that although prediction of the form of the rate law for a reverse reaction given the rate law for the forward reaction is not certain, the number of possibilities is limited because of relationships described. (JN)

  2. Department of Nuclear Reactions: Overview

    International Nuclear Information System (INIS)

    Rusek, K.

    2001-01-01

    Full text: The last year of the twentieth-century was productive for our Department. Although the name of the Department suggests that we are all involved in investigations of nuclear reactions, in fact our activities are spread over three major domains: nuclear, atomic and material physics. Some of the projects we were involved in the last year have been realized using national facilities and accelerators, like the Van de Graaff accelerator of our Department at 69 Hoza Street, Warsaw Cyclotron U-200P of Warsaw University, and compact C30 cyclotron of our Institute at Swierk. Other projects were done abroad, using facilities of the Gesellschaft fuer Schwerionenforschung in Darmstadt, Institute de Physique Nucleaire at Orsay, and Universitaet Erlangen-Nuernberg in Erlangen. We carried out our work in close collaborations with physicists from many laboratories, Polish and foreign. - Low energy nuclear reactions. In collaboration with scientists from Ukraine experiments, using heavy ion beam provided by the Warsaw Cyclotron, were started. The aim of the experiments is to study nuclear reactions leading to the exotic light nuclei in exit channels and energy dependence of the nucleus - nucleus interaction. Efforts were made to develop a multistep direct model of nuclear reactions. In the model contributions due to the low energy collective excitations were taken into account. Good agreement with the experimental data was achieved. - Multifragmentation of relativistic heavy ions. ALADIN Collaboration studied multifragmentation reactions induced by relativistic heavy ions. The main activities of our scientists concentrated on an upgrade of the detecting system in order to replace photo multipliers with large area avalanche photodiodes in the central section of the TOF-wall. Some tests of the photodiodes manufactured by Advanced Photonix Inc. were performed using standard β - and γ-sources. - Structure of a nucleon. Decay properties of the Roper resonance were studied. A

  3. Reactions of butadiyne. 1: The reaction with hydrogen atoms

    Science.gov (United States)

    Schwanebeck, W.; Warnatz, J.

    1984-01-01

    The reaction of hydrogen (H) atoms with butadiene (C4H2) was studied at room temperature in a pressure range between w mbar and 10 mbar. The primary step was an addition of H to C4H2 which is in its high pressure range at p 1 mbar. Under these conditions the following addition of a second H atom lies in the transition region between low and high pressure range. Vibrationally excited C4H4 can be deactivated to form buten-(1)-yne-(3)(C4H4) or decomposes into two C2H2 molecules. The rate constant at room temperature for primary step is given. The second order rate constant for the consumption of buten-(1)-yne-(3) is an H atom excess at room temperature is given.

  4. Fundamental study on reaction of lead-bismuth eutectic and sodium. Identification of reaction products and examination of reaction behavior

    International Nuclear Information System (INIS)

    Saito, Jun-ichi; Hirakawa, Yasushi

    2003-09-01

    A simplified secondary sodium cooling system utilizing lead-bismuth eutectic as an intermediate coolant has been selected as one of candidate systems for the 'Feasibility Studies on Commercialized Fast Reactor System'. In this study, fundamental reaction experiments have been performed to understand a reaction behavior between sodium and lead-bismuth. In order to identify the reaction products and to elucidate a reaction process, sampling and X-ray diffraction analysis of the reaction products are carried out. Following results are obtained. (1) The principal reaction products which formed in sodium and lead-bismuth ternary system are BiNa 3 and Pb 4 Na 15 intermetallic compounds. These two reaction products are identified irrespective of either primary sample content or sampling temperature. (2) Pb 3 Na intermetallic compound is identified in the reaction products for the first time. (3) The principal reaction product which formed in sodium and bismuth binary system is BiNa 3 intermetallic compound. (4) The reaction products which formed in sodium and lead binary system consist of various intermetallic compounds of sodium and lead system. Single phase of an intermetallic compound can not be obtained in this system. Based on these X-ray diffraction analyses, reaction process models of formation and dissolution are proposed. (author)

  5. Department of Nuclear Reactions: Overview

    International Nuclear Information System (INIS)

    Rusek, K.

    2003-01-01

    Full text: In 2002, the Department has been involved in two new experimental programmes. Our colleagues led by Prof. Pawel Zupranski joined a large international collaboration HERMES and took part in experiments at DESY devoted to the study of the spin structure of the nucleon. Another group directed by Associate Prof. Bogdan Zwieglinski has worked on a conceptual design of a new generation detector PANDA (Proton-Antiproton Detection) which will be used in future experiments at GSI. Moreover, the experimental programmes covering three major domains of our scientific activities: nuclear physics, materials research and atomic physics were continued. - Nuclear physics: Experimental studies of nuclear reactions induced by heavy ions provided by the Warsaw U-200P Cyclotron were performed in collaboration with scientists from the Institute for Nuclear Studies in Kiev, Ukraine. The aim of the experiments was to investigate isotopic effects in the scattering of 11 B from carbon nuclides. Also, excited states of 6 Li predicted theoretically but never seen in experiments were investigated by means of one-neutron transfer reactions. Proton induced reactions were investigated theoretically by means of the multistep-direct model. Good agreement with the experimental data was achieved. The mechanism of fragments production in collisions of 197 Au with a gold target in the wide range of energies was studied by ALADIN and INDRA Collaborations. The production of η mesons from proton - proton collisions was investigated experimentally at the Juelich Cooler Synchrotron COSY. - Atomic physics: The ionisation of Au, Bi, Th and U atoms by Si ions was investigated in collaboration with the Swietokrzyska Academy, Kielce, and the University of Erlangen-Nuernberg. - Materials research: The sensitivity of the Solid State Nuclear Track PM-355 detectors was tested against intensive gamma and electron radiation. Moreover, using a monoenergetic sulphur ion beam from the Warsaw Cyclotron, the

  6. Kinetic studies of elementary chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Durant, J.L. Jr. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    This program concerning kinetic studies of elementary chemical reactions is presently focussed on understanding reactions of NH{sub x} species. To reach this goal, the author is pursuing experimental studies of reaction rate coefficients and product branching fractions as well as using electronic structure calculations to calculate transition state properties and reaction rate calculations to relate these properties to predicted kinetic behavior. The synergy existing between the experimental and theoretical studies allow one to gain a deeper insight into more complex elementary reactions.

  7. Incidents of chemical reactions in cell equipment

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, N.M.; Barlow, C.R. [Uranium Enrichment Organization, Oak Ridge, TN (United States)

    1991-12-31

    Strongly exothermic reactions can occur between equipment structural components and process gases under certain accident conditions in the diffusion enrichment cascades. This paper describes the conditions required for initiation of these reactions, and describes the range of such reactions experienced over nearly 50 years of equipment operation in the US uranium enrichment program. Factors are cited which can promote or limit the destructive extent of these reactions, and process operations are described which are designed to control the reactions to minimize equipment damage, downtime, and the possibility of material releases.

  8. Computed potential energy surfaces for chemical reactions

    Science.gov (United States)

    Walch, Stephen P.

    1994-01-01

    Quantum mechanical methods have been used to compute potential energy surfaces for chemical reactions. The reactions studied were among those believed to be important to the NASP and HSR programs and included the recombination of two H atoms with several different third bodies; the reactions in the thermal Zeldovich mechanism; the reactions of H atom with O2, N2, and NO; reactions involved in the thermal De-NO(x) process; and the reaction of CH(squared Pi) with N2 (leading to 'prompt NO'). These potential energy surfaces have been used to compute reaction rate constants and rates of unimolecular decomposition. An additional application was the calculation of transport properties of gases using a semiclassical approximation (and in the case of interactions involving hydrogen inclusion of quantum mechanical effects).

  9. Department of Nuclear Reactions - Overview

    International Nuclear Information System (INIS)

    Budzanowski, A.

    1999-01-01

    Full text: The year 1998 can be considered as very successful both in harvesting important results from the existing collaborations as well as establishing new ones. In the frame of the COSY-11 collaboration cross section for η' production in p-p collision close to the threshold has been measured. In the region of excess energy between 1.5 and 4.1 MeV the η' cross sections are much lower than those of the π 0 and η production. There seems to be no indication that N * resonance doorway-like state governs the reaction mechanisms. The determined coupling constant g η'pp appears to be consistent with the prediction of the simple quark model. Results were published in Phys. Rev. Letters. Using the GEM detector, investigations of the isospin symmetry breaking were performed. Two reactions channels 3 Heπ 0 and 3 Hπ + from the reaction at proton momenta 700, 767, and 825 MeV/c were measured. Data analysis is in progress. The model of the meson cloud in the nucleon which is a speciality of our department has been successfully applied to explain the leading proton and neutron cross sections from the e + or e - proton collisions at the HERA ring. General formulas to calculate polarization of the particles with spin transmitted through the barrier in the presence of strong magnetic fields were obtained. New collaboration between our laboratory and the Institute for Nuclear Research in Kiev has been established. One PhD thesis was completed in the frame of this collaboration. We joined the new collaboration with Lund University concerning studies of hot nuclear matter properties using heavy ions from CELSIUS ring. First test of the phoswich detector for the forward wall was performed in Uppsala. Isoscalar giant dipole resonance strength distribution 3 ℎω has been evaluated in 208 Pb in the space of 1p1h and 2p2h excitation. The centroid energy of this state can directly be related to the nuclear incompressibility module. Our result indicates rather large values of

  10. The OH + HBr reaction revisited

    Science.gov (United States)

    Ravishankara, A. R.; Wine, P. H.; Wells, J. R.

    1985-01-01

    Variable-temperature measurements of the rate coefficient /k(1)/ for the reaction OH + HBr yield Br + H2O are presented. The measurements are verified by two techniques: one involved a 266-nm pulsed-laser photolysis of O3/H2O/HBr/He mixtures in conjunction with time-resolved resonance fluorescence detection of OH, the second comprised pulsed laser-induced fluorescence detection of OH following 248-nm pulsed-laser photolysis of H2O2/HBr/Ar mixtures. It is reported that k(1) = (11.9 + or -1.4 x 10 to the -12th (cu cm)/(molecule)(s) independent of temperature. The measurements are compared with other available results.

  11. Stochastic chemical reactions in microdomains

    Science.gov (United States)

    Holcman, D.; Schuss, Z.

    2005-03-01

    Traditional chemical kinetics may be inappropriate to describe chemical reactions in microdomains involving only a small number of substrate and reactant molecules. Starting with the stochastic dynamics of the molecules, we derive a master-diffusion equation for the joint probability density of a mobile reactant and the number of bound substrate in a confined domain. We use the equation to calculate the fluctuations in the number of bound substrate molecules as a function of initial reactant distribution. A second model is presented based on a Markov description of the binding and unbinding and on the mean first passage time of a molecule to a small portion of the boundary. These models can be used for the description of noise due to gating of ionic channels by random binding and unbinding of ligands in biological sensor cells, such as olfactory cilia, photoreceptors, hair cells in the cochlea.

  12. Selected aspects of fusion reactions

    International Nuclear Information System (INIS)

    Lacroix, D.

    2003-01-01

    In this lecture, we present selected aspects of nuclear fusion. The importance of the initial geometry of the reaction and its relation to fusion barrier are first discussed. The effect of deformation leading to the notion of barrier distribution is then illustrated. After a brief overview of the advantages of macroscopic theories, the dynamics of nuclear system under large amplitude motion is reviewed. The di-nuclear concept is presented to understand the competition between fusion and quasi-fission. This concept is then generalized to account for the dissipative dynamics in multidimensional collective space. The last part of this lecture is devoted to new aspects encountered with radioactive beams specific properties of very extended neutron rich system, influence of pygmy or soft dipole resonances and charge exchange far from stability are discussed. (author)

  13. Cold molecules, collisions and reactions

    Science.gov (United States)

    Hecker Denschlag, Johannes

    2016-05-01

    I will report on recent experiments of my group where we have been studying the formation of ultracold diatomic molecules and their subsequent inelastic/reactive collisions. For example, in one of these experiments we investigate collisions of triplet Rb2 molecules in the rovibrational ground state. We observe fast molecular loss and compare the measured loss rates to predictions based on universality. In another set of experiments we investigate the formation of (BaRb)+ molecules after three-body recombination of a single Ba+ ion with two Rb atoms in an ultracold gas of Rb atoms. Our investigations indicate that the formed (BaRb)+ molecules are weakly bound and that several secondary processes take place ranging from photodissociation of the (BaRb)+ molecule to reactive collisions with Rb atoms. I will explain how we can experimentally distinguish these processes and what the typical reaction rates are. Support from the German Research foundation DFG and the European Community is acknowledged.

  14. Department of Nuclear Reactions: Overview

    International Nuclear Information System (INIS)

    Rusek, K.

    2004-01-01

    Full text: In spite of reduced personnel the number of papers published and in press exceeded fifty, almost ten more than a year ago. Another good sign is the growing number of PhD students. The following short reports cover the three major domains of our scientific activities: nuclear, material and atomic physics. Nuclear physics: The structure of light nuclei was investigated, and studies of nuclear reactions induced by heavy ions were performed including experiments at the Heavy Ion Laboratory of Warsaw University. The experiments were carried out in collaboration with scientists from the Institute of Nuclear Research from Kiev, Ukraine. Proton induced reactions on zirconium were investigated theoretically by means of a multistep-direct model extended for the unbound particle - hole states. Good agreement with the experimental data was achieved. Isospin effects in multifragmentation of relativistic heavy ions were studied by the ALADIN Collaboration. Elements of a new generation detector PANDA were tested experimentally using a proton beam provided by the C-30 compact cyclotron at Swierk. Evidence of a narrow baryon state was found in a quasi - real photoproduction on the deuterium target by the HERMES Collaboration. Atomic physics: Ionisation of selected heavy elements by sulphur ions was investigated in collaboration with the Swietokrzyska Academy, Kielce. Materials research: Hydrogen release from ultrahigh molecular weight polythene was investigated by means of an α - particle beam from the Van de Graaff accelerator of our Department. Last but not least, many of our colleagues have been involved in education. Lectures on nuclear physics, accelerators, detectors used in nuclear research as well as nuclear methods applied in solid state studies for students from many high schools of Warsaw and for students of Warsaw University were given by Dr. Andrzej Korman and Dr. Lech Nowicki. Also, our Department made a significant contribution to the 7 th Science

  15. Subdiffusion-reaction processes with A →B reactions versus subdiffusion-reaction processes with A +B→B reactions

    Science.gov (United States)

    Kosztołowicz, Tadeusz; Lewandowska, Katarzyna D.

    2014-09-01

    We consider the subdiffusion-reaction process with reactions of a type A +B→B (in which particles A are assumed to be mobile, whereas B are assumed to be static) in comparison to the subdiffusion-reaction process with A →B reactions which was studied by Sokolov, Schmidt, and Sagués [Phys. Rev. E 73, 031102 (2006), 10.1103/PhysRevE.73.031102]. In both processes a rule that reactions can only occur between particles which continue to exist is taken into account. Although in both processes a probability of the vanishing of particle A due to a reaction is independent of both time and space variables (assuming that in the system with the A +B→B reactions, particles B are distributed homogeneously), we show that subdiffusion-reaction equations describing these processes as well as their Green's functions are qualitatively different. The reason for this difference is as follows. In the case of the former reaction, particles A and B have to meet with some probability before the reaction occurs in contradiction with the case of the latter reaction. For the subdiffusion process with the A +B→B reactions we consider three models which differ in some details concerning a description of the reactions. We base the method considered in this paper on a random walk model in a system with both discrete time and discrete space variables. Then the system with discrete variables is transformed into a system with both continuous time and continuous space variables. Such a method seems to be convenient in analyzing subdiffusion-reaction processes with partially absorbing or partially reflecting walls. The reason is that within this method we can determine Green's functions without a necessity of solving a fractional differential subdiffusion-reaction equation with boundary conditions at the walls. As an example, we use the model to find the Green's functions for a subdiffusive reaction system (with the reactions mentioned above), which is bounded by a partially absorbing wall

  16. RxnFinder: biochemical reaction search engines using molecular structures, molecular fragments and reaction similarity.

    Science.gov (United States)

    Hu, Qian-Nan; Deng, Zhe; Hu, Huanan; Cao, Dong-Sheng; Liang, Yi-Zeng

    2011-09-01

    Biochemical reactions play a key role to help sustain life and allow cells to grow. RxnFinder was developed to search biochemical reactions from KEGG reaction database using three search criteria: molecular structures, molecular fragments and reaction similarity. RxnFinder is helpful to get reference reactions for biosynthesis and xenobiotics metabolism. RxnFinder is freely available via: http://sdd.whu.edu.cn/rxnfinder. qnhu@whu.edu.cn.

  17. Reaction time variability in ADHD: a review.

    Science.gov (United States)

    Tamm, Leanne; Narad, Megan E; Antonini, Tanya N; O'Brien, Kathleen M; Hawk, Larry W; Epstein, Jeffery N

    2012-07-01

    For the past decade, intra-individual variability in reaction times on computerized tasks has become a central focus of cognitive research on Attention-Deficit/Hyperactivity Disorder (ADHD). Numerous studies document increased reaction time variability among children and adults with ADHD, relative to typically developing controls. However, direct comparisons with other disorders with heightened reaction time variability are virtually nonexistent, despite their potential to inform our understanding of the phenomenon. A growing literature examines the sensitivity of reaction time variability to theoretically and clinically relevant manipulations. There is strong evidence that stimulus treatment reduces reaction time variability during a range of cognitive tasks, but the literature is mixed regarding the impact of motivational incentives and variation in stimulus event rate. Most studies of reaction time variability implicitly assume that heightened reaction time variability reflects occasional lapses in attention, and the dominant neurophysiological interpretation suggests this variability is linked to intrusions of task-negative brain network activity during task performance. Work examining the behavioral and neurophysiological correlates of reaction time variability provides some support for these hypotheses, but considerably more work is needed in this area. Finally, because conclusions from each of domains reviewed are limited by the wide range of measures used to measure reaction time variability, this review highlights the need for increased attention to the cognitive and motivational context in which variability is assessed and recommends that future work always supplement macro-level variability indices with metrics that isolate particular components of reaction time variability.

  18. Explorations into Chemical Reactions and Biochemical Pathways.

    Science.gov (United States)

    Gasteiger, Johann

    2016-12-01

    A brief overview of the work in the research group of the present author on extracting knowledge from chemical reaction data is presented. Methods have been developed to calculate physicochemical effects at the reaction site. It is shown that these physicochemical effects can quite favourably be used to derive equations for the calculation of data on gas phase reactions and on reactions in solution such as aqueous acidity of alcohols or carboxylic acids or the hydrolysis of amides. Furthermore, it is shown that these physicochemical effects are quite effective for assigning reactions into reaction classes that correspond to chemical knowledge. Biochemical reactions constitute a particularly interesting and challenging task for increasing our understanding of living species. The BioPath.Database is a rich source of information on biochemical reactions and has been used for a variety of applications of chemical, biological, or medicinal interests. Thus, it was shown that biochemical reactions can be assigned by the physicochemical effects into classes that correspond to the classification of enzymes by the EC numbers. Furthermore, 3D models of reaction intermediates can be used for searching for novel enzyme inhibitors. It was shown in a combined application of chemoinformatics and bioinformatics that essential pathways of diseases can be uncovered. Furthermore, a study showed that bacterial flavor-forming pathways can be discovered. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Department of Nuclear Reactions: Overview

    International Nuclear Information System (INIS)

    Rusek, K.

    1999-01-01

    Full text: The Department of Nuclear Reactions had a very productive year. The following reports cover three major domains of our activities: nuclear, material and atomic physics. One of the current questions in modern nuclear physics is question of the phase transitions in nuclear matter. Our physicists, the members of the ALADIN Collaboration at Gesellschaft fuer Schwerionenforschung, participated in new experiments exploring properties of highly excited nuclear matter and the phenomenon of the liquid - gas phase transition. The experiments yielded a number of important results. Details can be found in the three short reports presented in this volume. Structure of a nucleon is another important subject of nuclear science research. In the last year energy region of Δ resonance has been investigated by means of charge exchange reaction. The experiment was performed at Laboratory National Saturne in Saclay by SPESIV-π collaboration consisting of physicist from Institute of Nuclear Physics Orsay, Niels Bohr Institute Copenhagen and from our Department. The main achievement of the experiment was evidence for a Δ - hole attraction in the spin longitudinal channel. Reactions induced by radioactive ion beams such as 6 He recently attract a lot of interest. There exist some evidences that the 6 He nucleus has a two-neutron halo structure similar to that well established for 11 Li. An analysis of 6 He + 4 He scattering data reported in this volume revealed some similarities between the loosely bound 6 Li nucleus and the neutron rich 6 He. Research in material physics has focused on two basic topics: a crystallographic model of uranium dioxide, a material currently used as a nuclear fuel and transformations of defects in GaAs crystals at low temperature. The investigations have been carried out in a wide collaboration with scientists from the University of Jena, Research Center Karlsruhe and Centre de Spectrometrie Nucleaire Orsay. Some experiments have been performed at

  20. Department of Nuclear Reactions: Overview

    International Nuclear Information System (INIS)

    Rusek, K.

    1998-01-01

    (full text) During the last year our activities were spread over the three major domains: nuclear, atomic and material physics. The nuclear physics experimental programme covered a broad range of nuclear reactions induced by light and heavy ions. New experiments were performed at the compact C-30 cyclotron at Swierk, at University of Jyvaeskylae, GSI Darmstadt, LN Saturne. Prospects for future experiments on nucleon structure at Forschungszentrum Juelich were open. The collaboration with INR Kiev was tightened and work was done in order to prepare experiments at the C-200 heavy ion cyclotron in Warsaw. An effort to install the ion guide isotope separator on line (IGISOL) at the C-200 cyclotron has also to be mentioned A half a year stay of Dr. Nicholas Keeley in the Department, who received The Royal Society/Polish Academy of Science grant, resulted in many interesting results on breakup of light nuclei. Details can be found in the short abstracts presented in this report. As far as atomic physics is concerned, the activity of a group lead by Prof. Marian Jaskola yielded various new results. The experiments were performed at the University of Erlangen, in close collaboration with the Pedagogical University in Kielce and the University of Basel. Fast neutrons generated in the 3 H(d,n) 4 He reaction induced by the 2 MeV deuteron beam from the Van der Graaff accelerator at the Department were used to calibrate solid state-nuclear-track detectors. This was a very good year for material physics research: Jan Kaczanowski and Slawomir Kwiatkawski received Ph.D. degrees based on dissertation research performed in the material physics research programme, while Pawel Kolodziej completed his MSc. thesis in collaboration with the Institute of Electronic Materials Technology in Warsaw, Research Center Karlsruhe, University of Jena and CSNSM Orsay many results were obtained. Lech Nowicki and Prof. Andrzej Turos were awarded by the Director of the IPJ prizes for their scientific

  1. ReactionPredictor: prediction of complex chemical reactions at the mechanistic level using machine learning.

    Science.gov (United States)

    Kayala, Matthew A; Baldi, Pierre

    2012-10-22

    Proposing reasonable mechanisms and predicting the course of chemical reactions is important to the practice of organic chemistry. Approaches to reaction prediction have historically used obfuscating representations and manually encoded patterns or rules. Here we present ReactionPredictor, a machine learning approach to reaction prediction that models elementary, mechanistic reactions as interactions between approximate molecular orbitals (MOs). A training data set of productive reactions known to occur at reasonable rates and yields and verified by inclusion in the literature or textbooks is derived from an existing rule-based system and expanded upon with manual curation from graduate level textbooks. Using this training data set of complex polar, hypervalent, radical, and pericyclic reactions, a two-stage machine learning prediction framework is trained and validated. In the first stage, filtering models trained at the level of individual MOs are used to reduce the space of possible reactions to consider. In the second stage, ranking models over the filtered space of possible reactions are used to order the reactions such that the productive reactions are the top ranked. The resulting model, ReactionPredictor, perfectly ranks polar reactions 78.1% of the time and recovers all productive reactions 95.7% of the time when allowing for small numbers of errors. Pericyclic and radical reactions are perfectly ranked 85.8% and 77.0% of the time, respectively, rising to >93% recovery for both reaction types with a small number of allowed errors. Decisions about which of the polar, pericyclic, or radical reaction type ranking models to use can be made with >99% accuracy. Finally, for multistep reaction pathways, we implement the first mechanistic pathway predictor using constrained tree-search to discover a set of reasonable mechanistic steps from given reactants to given products. Webserver implementations of both the single step and pathway versions of Reaction

  2. A clock reaction based on molybdenum blue.

    Science.gov (United States)

    Neuenschwander, Ulrich; Negron, Arnaldo; Jensen, Klavs F

    2013-05-30

    Clock reactions are rare kinetic phenomena, so far limited mostly to systems with ionic oxoacids and oxoanions in water. We report a new clock reaction in cyclohexanol that forms molybdenum blue from a noncharged, yellow molybdenum complex as precursor, in the presence of hydrogen peroxide. Interestingly, the concomitant color change is reversible, enabling multiple clock cycles to be executed consecutively. The kinetics of the clock reaction were experimentally characterized, and by adding insights from quantum chemical calculations, a plausible reaction mechanism was postulated. Key elementary reaction steps comprise sigmatropic rearrangements with five-membered or bicyclo[3.1.0] transition states. Importantly, numerical kinetic modeling demonstrated the mechanism's ability to reproduce the experimental findings. It also revealed that clock behavior is intimately connected to the sudden exhaustion of hydrogen peroxide. Due to the stoichiometric coproduction of ketone, the reaction bears potential for application in alcohol oxidation catalysis.

  3. Delayed reactions to reusable protective gloves.

    Science.gov (United States)

    Pontén, Ann; Dubnika, Inese

    2009-04-01

    The materials in plastic protective gloves are thought to cause less contact allergy than rubber gloves. Our aim was to estimate the frequency of delayed reactions to different types of reusable protective gloves among dermatitis patients. 2 x 2 cm pieces of polyvinyl chloride (PVC) gloves, nitrile gloves, and natural rubber latex (NRL) gloves were tested as is in consecutive dermatitis patients tested with the baseline series. Among 658 patients, 6 patients reacted to PVC gloves and 6 patients to the NRL gloves. None reacted to both these types of gloves. Five of six patients with reactions to rubber gloves reacted to thiuram mix in the baseline series. Delayed reactions to reusable PVC gloves may be as common as to reusable NRL gloves. In contrast to most reactions to the NRL glove, the reactions to the PVC glove had no obvious association with reactions to any allergen(s) in the baseline series.

  4. Ladle Metallurgy Kinetics: Inclusion-Inclusion Reactions

    Science.gov (United States)

    Pistorius, P. Chris

    An example is presented to illustrate the joint effect of local reaction equilibria and mass transfer limitations, for reactions during ladle refining of steel. The example relies on some of the kinetic principles that David Robertson has employed to quantify many metallurgical processes. In calcium treatment of alumina inclusions in aluminum-killed steels, solid CaS forms as an intermediate reaction product. During subsequent reaction, CaS disappears and calcium aluminate forms; at the same time, aluminum and sulfur dissolve in the steel. Kinetic analysis shows that the rate of this reaction is not limited by mass transfer of dissolved aluminum and sulfur away from the reacting inclusions. The reaction rate is likely limited by transport of dissolved calcium. This example also illustrates the use of FactSage macros for kinetic modeling.

  5. Orienting reaction in patients with night terrors.

    Science.gov (United States)

    Rogozea, R; Florea-Ciocoiu, V

    1985-08-01

    A polygraphic study of the somatic (electromyogram), autonomic (finger plethysmogram, galvanic skin reaction, respiration, pulse), and electroencephalographic (acoustic-evoked potential and EEG-blocking reaction) components of the orienting reaction elicited by an auditory stimulus was performed in 36 patients with night terrors and in 72 matched subjects in two control groups. The study showed a significantly more intense orienting reaction in patients with night terrors than in normal subjects (Control Group I). Moreover, the orienting reaction intensity in subjects with night terrors was significantly lower than in patients with symptomatic epilepsy (Control Group II). The orienting reactions of patients with night terrors depended on the patient's age, the history of nocturnal episodes, and their clinical form, as well as on etiology.

  6. Proton transfer reaction - mass spectrometry

    International Nuclear Information System (INIS)

    Cappellin, L.

    2012-01-01

    Proton transfer reaction mass spectrometry (PTR-MS) provides on-line monitoring of volatile organic compounds (VOCs) with a low detection threshold and a fast response time. Commercially available set-ups are usually based on quadrupole analysers but recently new instruments based on time-of-flight (PTR-ToF-MS) analysers have been proposed and commercialized. PTR-MS has been successfully applied to a variety of fields including environmental science, food science and technology, plant physiology and medical science. Many new challenges arise from the newly available PTR-ToF-MS instruments, ranging from mass calibration and absolute VOC concentration determination to data mining and sample classification. This thesis addresses some of these problems in a coherent framework. Moreover, relevant applications in food science and technology are presented. It includes twelve papers published in peer reviewed journals. Some of them address methodological issues regarding PTR-ToF-MS; the others contain applicative studies of PTR-ToF-MS to food science and technology. Among them, there are the first two published applications of PTR-ToF-MS in this field. (author)

  7. Alchemical derivatives of reaction energetics

    Science.gov (United States)

    Sheppard, Daniel; Henkelman, Graeme; von Lilienfeld, O. Anatole

    2010-08-01

    Based on molecular grand canonical ensemble density functional theory, we present a theoretical description of how reaction barriers and enthalpies change as atoms in the system are subjected to alchemical transformations, from one element into another. The change in the energy barrier for the umbrella inversion of ammonia is calculated along an alchemical path in which the molecule is transformed into water, and the change in the enthalpy of protonation for methane is calculated as the molecule is transformed into a neon atom via ammonia, water, and hydrogen fluoride. Alchemical derivatives are calculated analytically from the electrostatic potential in the unperturbed system, and compared to numerical derivatives calculated with finite difference interpolation of the pseudopotentials for the atoms being transformed. Good agreement is found between the analytical and numerical derivatives. Alchemical derivatives are also shown to be predictive for integer changes in atomic numbers for oxygen binding to a 79 atom palladium nanoparticle, illustrating their potential use in gradient-based optimization algorithms for the rational design of catalysts.

  8. Quantum indistinguishability in chemical reactions.

    Science.gov (United States)

    Fisher, Matthew P A; Radzihovsky, Leo

    2018-04-30

    Quantum indistinguishability plays a crucial role in many low-energy physical phenomena, from quantum fluids to molecular spectroscopy. It is, however, typically ignored in most high-temperature processes, particularly for ionic coordinates, implicitly assumed to be distinguishable, incoherent, and thus well approximated classically. We explore enzymatic chemical reactions involving small symmetric molecules and argue that in many situations a full quantum treatment of collective nuclear degrees of freedom is essential. Supported by several physical arguments, we conjecture a "quantum dynamical selection" (QDS) rule for small symmetric molecules that precludes chemical processes that involve direct transitions from orbitally nonsymmetric molecular states. As we propose and discuss, the implications of the QDS rule include ( i ) a differential chemical reactivity of para- and orthohydrogen, ( ii ) a mechanism for inducing intermolecular quantum entanglement of nuclear spins, ( iii ) a mass-independent isotope fractionation mechanism, ( iv ) an explanation of the enhanced chemical activity of "reactive oxygen species", ( v ) illuminating the importance of ortho-water molecules in modulating the quantum dynamics of liquid water, and ( vi ) providing the critical quantum-to-biochemical linkage in the nuclear spin model of the (putative) quantum brain, among others.

  9. Interfacial reactions in lithium batteries

    Science.gov (United States)

    Chen, Zonghai; Amine, Rachid; Ma, Zi-Feng; Amine, Khalil

    2017-08-01

    The lithium-ion battery was first commercially introduced by Sony Corporation in 1991 using LiCoO2 as the cathode material and mesocarbon microbeads (MCMBs) as the anode material. After continuous research and development for 25 years, lithium-ion batteries have been the dominant energy storage device for modern portable electronics, as well as for emerging applications for electric vehicles and smart grids. It is clear that the success of lithium-ion technologies is rooted to the existence of a solid electrolyte interphase (SEI) that kinetically suppresses parasitic reactions between the lithiated graphitic anodes and the carbonate-based non-aqueous electrolytes. Recently, major attention has been paid to the importance of a similar passivation/protection layer on the surface of cathode materials, aiming for a rational design of high-energy-density lithium-ion batteries with extended cycle/calendar life. In this article, the physical model of the SEI, as well as recent research efforts to understand the nature and role of the SEI are summarized, and future perspectives on this important research field will also be presented.

  10. Estimating the Backup Reaction Wheel Orientation Using Reaction Wheel Spin Rates Flight Telemetry from a Spacecraft

    Science.gov (United States)

    Rizvi, Farheen

    2013-01-01

    A report describes a model that estimates the orientation of the backup reaction wheel using the reaction wheel spin rates telemetry from a spacecraft. Attitude control via the reaction wheel assembly (RWA) onboard a spacecraft uses three reaction wheels (one wheel per axis) and a backup to accommodate any wheel degradation throughout the course of the mission. The spacecraft dynamics prediction depends upon the correct knowledge of the reaction wheel orientations. Thus, it is vital to determine the actual orientation of the reaction wheels such that the correct spacecraft dynamics can be predicted. The conservation of angular momentum is used to estimate the orientation of the backup reaction wheel from the prime and backup reaction wheel spin rates data. The method is applied in estimating the orientation of the backup wheel onboard the Cassini spacecraft. The flight telemetry from the March 2011 prime and backup RWA swap activity on Cassini is used to obtain the best estimate for the backup reaction wheel orientation.

  11. ADVERSE DRUG REACTION (ADR) MONITORING AND PHARMACOVIGILANCE

    OpenAIRE

    D. KAVITHA

    2013-01-01

    The need for systematic follow up of medicines for adverse drug reactions once they are introduced into general use has been widely recognised today. Even in developing countries like India, national pharmacovigilance programme has been started for monitoring adverse drug reactions. In its first year this program mainly aimed to foster the culture of ADR notification among health care professionals. As a part of health care team every pharmacist must have knowledge about adverse drug reaction...

  12. Physical organic studies of organometallic reactions

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, Robert G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1981-01-01

    The mechanisms of reactions of organotransition metal complexes have only begun to be understood in detail during the last ten years. The complementary interaction of techniques and concepts developed earlier in studies of organic reaction mechanisms, with those commonly used in inorganic chetnistry, has played a crucial role in helping to elucidate organor.1etall.ic reaction mechanisms. A few systems in which this interaction has proved especially fruitful are discussed in this article.

  13. Molecular dynamics simulation of a chemical reaction

    International Nuclear Information System (INIS)

    Gorecki, J.; Gryko, J.

    1988-06-01

    Molecular dynamics is used to study the chemical reaction A+A→B+B. It is shown that the reaction rate constant follows the Arrhenius law both for Lennard-Jones and hard sphere interaction potentials between substrate particles. A. For the denser systems the reaction rate is proportional to the value of the radial distribution function at the contact point of two hard spheres. 10 refs, 4 figs

  14. Severe allergic reactions to guinea pig

    OpenAIRE

    Zacharisen, Michael C; Levy, Michael B; Shaw, Jeffrey L; Kurup, Viswanath P

    2005-01-01

    Abstract Background Allergic sensitization and reactions to guinea pig (Cavia porcellus) have been well documented in laboratory animal handlers, primarily manifesting as rhinitis, conjunctivitis, and asthma. Severe allergic reactions, however, are rare. Methods We report two patients with severe allergic reactions following non-occupational exposure to guinea pigs. The first patient, an 11-year-old female, developed ocular, nasal, skin and laryngeal edema symptoms immediately after handling ...

  15. Nucleon transfer reactions with radioactive beams

    Science.gov (United States)

    Wimmer, K.

    2018-03-01

    Transfer reactions are a valuable tool to study the single-particle structure of nuclei. At radioactive beam facilities transfer reactions have to be performed in inverse kinematics. This creates a number of experimental challenges, but it also has some advantages over normal kinematics measurements. An overview of the experimental and theoretical methods for transfer reactions, especially with radioactive beams, is presented. Recent experimental results and highlights on shell evolution in exotic nuclei are discussed.

  16. Mukaiyama Aldol Reactions in Aqueous Media

    OpenAIRE

    Kitanosono, Taku; Kobayashi, Shū

    2013-01-01

    Mukaiyama aldol reactions in aqueous media have been surveyed. While the original Mukaiyama aldol reactions entailed stoichiometric use of Lewis acids in organic solvents under strictly anhydrous conditions, Mukaiyama aldol reactions in aqueous media are not only suitable for green sustainable chemistry but are found to produce singular phenomena. These findings led to the discovery of a series of water-compatible Lewis acids such as lanthanide triflates in 1991. Our understanding on these be...

  17. Asian collaboration on nuclear reaction data compilation

    International Nuclear Information System (INIS)

    Aikawa, Masayuki; Furutachi, Naoya; Kato, Kiyoshi; Makinaga, Ayano; Devi, Vidya; Ichinkhorloo, Dagvadorj; Odsuren, Myagmarjav; Tsubakihara, Kohsuke; Katayama, Toshiyuki; Otuka, Naohiko

    2013-01-01

    Nuclear reaction data are essential for research and development in nuclear engineering, radiation therapy, nuclear physics and astrophysics. Experimental data must be compiled in a database and be accessible to nuclear data users. One of the nuclear reaction databases is the EXFOR database maintained by the International Network of Nuclear Reaction Data Centres (NRDC) under the auspices of the International Atomic Energy Agency. Recently, collaboration among the Asian NRDC members is being further developed under the support of the Asia-Africa Science Platform Program of the Japan Society for the Promotion of Science. We report the activity for three years to develop the Asian collaboration on nuclear reaction data compilation. (author)

  18. Experimental Studies of quasi-fission reactions

    International Nuclear Information System (INIS)

    Back, B.B.

    1989-01-01

    A large number of recent experimental studies have shown that a substantial fraction of the total reaction cross section in heavy-ion reactions is found in fission-like processes, which do not result from the fission decay of a completely fused system. Following the suggestion of Swiatecki such processes, which represents a complete relaxation of the relative kinetic energy and a substantial amount of net mass transfer between the two fragments, are denoted quasi-fission reactions. They are distinct from compound fission reactions by bypassing the stage of a completely fused system. This typically means that they are associated with short reaction times, which results in several measurable characteristics such as broken forward-backward symmetries, large anisotropies of the angular distributions and increased widths of the fragment mass distributions. The distinction between quasi-fission and deep inelastic reactions is less stringent and has the character of a gradual evolution from one reaction type to the other, as found also as quasi-elastic reaction evolves into deeply inelastic processes as a function of the total kinetic energy loss. In the present paper some of the experimental data characterizing quasi-fission reactions are reviewed and discussed. (author)

  19. Sodium-concrete reaction model development

    International Nuclear Information System (INIS)

    Nguyen, D.H.; Muhlestein, L.D.; Postma, A.K.

    1982-07-01

    Major observations have been formulated after reviewing test results for over 100 sodium-concrete reaction tests. The observations form the basis for developing a mechanistic model to predict the transient behavior of sodium-concrete reactions. The major observations are listed. Mechanisms associated with sodium and water transport to the reaction zone are identified, and represented by appropriate mathematical expressions. The model attempts to explain large-scale, long-term (100 h) test results were sodium-concrete reactions terminated even in the presence of unreacted sodium and concrete

  20. Catalytic enantioselective Reformatsky reaction with ketones

    NARCIS (Netherlands)

    Fernandez-Ibanez, M. Angeles; Macia, Beatriz; Minnaard, Adriaan J.; Feringa, Ben L.

    2008-01-01

    Chiral tertiary alcohols were obtained with good yields and enantioselectivities via a catalytic Reformatsky reaction with ketones, including the challenging diaryl ketones, using chiral BINOL derivatives.

  1. The unified theory of nuclear reactions

    International Nuclear Information System (INIS)

    Tobocman, W.

    A unified nuclear reaction theory is a formalism for the scattering reactions of many-body nuclear systems which is capable of describing both direct interaction and compound nucleus formation processes. The Feshbach projection operator formalism is the original unified nuclear reaction theory. An alternative unified nuclear reaction theory called the X-matrix formalism is described. The X-matrix formalism is a generalization of the Brown-de Dominicis formalism. It does not require projection operators and is readly applied to rearrangement collisions

  2. Screened Thermonuclear Reaction Rates on Magnetar Surfaces

    International Nuclear Information System (INIS)

    Hong-Lin, Liu; Zhi-Quan, Luo; Jing-Jing, Liu; Xiang-Jun, Lai

    2008-01-01

    Improving Salpeter's method, we discuss the effect of superstrong magnetic fields (such as those of magnetars) on thermonuclear reaction rates. These most interesting reactions, including the hydrogen burning by the CNO cycle and the helium burning by the triple alpha reaction, are investigated as examples on the magnetar surfaces. The obtained result shows that the superstrong magnetic fields can increase the thermonuclear reaction rates by many orders of magnitude. The enhancement may have significant influence for further study research of the magnetars, especially for the x-ray luminosity observation and the evolution of magnetars. (geophysics, astronomy, and astrophysics)

  3. Verification of cold nuclear fusion reaction, (1)

    International Nuclear Information System (INIS)

    Yoshida, Zenko; Aratono, Yasuyuki; Hirabayashi, Takakuni

    1991-01-01

    Can cold nuclear fusion reaction occur as is expected? If it occurs, what extent is its reaction probability? At present after 2 years elapsed since its beginning, the clear solution of these questions is not yet obtained. In many reaction systems employing different means, the experiments to confirm the cold nuclear fusion reaction have been attempted. In order to confirm that the nuclear fusion reaction of deuterium mutually has occurred, the neutrons, He-3, protons, tritium or generated heat, which were formed by the reaction and released from the system, are measured. Since it is considered that the frequency of the occurrence at normal temperature of the reaction is very low, it is necessary to select the most suitable method upon evaluating the limit of detection peculiar to the measuring methods. The methods of measuring neutrons, protons, gamma ray and generated heat, and the reaction systems by electrolytic process and dry process are explained. The detection of plural kinds of the reaction products and the confirmation of synchronism of signals are important. (K.I.)

  4. A study on sodium-concrete reaction

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Jae Heum; Min, Byong Hun [Suwon University, Suwon (Korea, Republic of)

    1997-07-01

    A small sodium-concrete reaction facility was designed, manufactured and installed. this facility has been operated under inert gas(N{sub 2}) with different experimental variables such as sodium injection temperature, injection amount of sodium, aging period of concrete, sodium reservoir temperature. As a result, it was found that sodium injection temperature and injected amount of sodium has little effect on sodium-concrete reaction. However, sodium reservoir temperature and aging period of concrete has relatively high impact on sodium-concrete reaction. Sodium-concrete reaction model has also been developed and compared with experimental results. (Author) 51 refs., 16 tabs., 64 figs.

  5. Bimolecular reactions of carbenes: Proton transfer mechanism

    Science.gov (United States)

    Abu-Saleh, Abd Al-Aziz A.; Almatarneh, Mansour H.; Poirier, Raymond A.

    2018-04-01

    Here we report the bimolecular reaction of trifluoromethylhydroxycarbene conformers and the water-mediated mechanism of the 1,2-proton shift for the unimolecular trans-conformer by using quantum chemical calculations. The CCSD(T)/cc-pVTZ//MP2/cc-pVDZ potential-energy profile of the bimolecular reaction of cis- and trans-trifluoromethylhydroxycarbene, shows the lowest gas-phase barrier height of 13 kJ mol-1 compared to the recently reported value of 128 kJ mol-1 for the unimolecular reaction. We expect bimolecular reactions of carbene's stereoisomers will open a valuable field for new and useful synthetic strategies.

  6. Catalytic Wittig and aza-Wittig reactions

    Directory of Open Access Journals (Sweden)

    Zhiqi Lao

    2016-11-01

    Full Text Available This review surveys the literature regarding the development of catalytic versions of the Wittig and aza-Wittig reactions. The first section summarizes how arsenic and tellurium-based catalytic Wittig-type reaction systems were developed first due to the relatively easy reduction of the oxides involved. This is followed by a presentation of the current state of the art regarding phosphine-catalyzed Wittig reactions. The second section covers the field of related catalytic aza-Wittig reactions that are catalyzed by both phosphine oxides and phosphines.

  7. Catalytic Wittig and aza-Wittig reactions.

    Science.gov (United States)

    Lao, Zhiqi; Toy, Patrick H

    2016-01-01

    This review surveys the literature regarding the development of catalytic versions of the Wittig and aza-Wittig reactions. The first section summarizes how arsenic and tellurium-based catalytic Wittig-type reaction systems were developed first due to the relatively easy reduction of the oxides involved. This is followed by a presentation of the current state of the art regarding phosphine-catalyzed Wittig reactions. The second section covers the field of related catalytic aza-Wittig reactions that are catalyzed by both phosphine oxides and phosphines.

  8. Chemical reactions in low-g

    Science.gov (United States)

    Grodzka, P. G.; Facemire, B. R.

    1978-01-01

    The Apollo-Soyuz flight experiment, 'Chemical Foams' demonstrated that foams and air/liquid dispersions are much more stable in low-gravity than on the ground. It thus should be possible to conduct unique chemical reactions in space foams. The low-g results and subsequent ground work on the formaldehyde clock reaction indicate that the reaction is strongly influenced by (1) dissociated and undissociated solution species being adsorbed at solid/liquid and gas/liquid surfaces and (2) chemical reaction rates apparently being affected by long-range forces determined by the liquid mass and the extent and nature of all surface interfaces.

  9. Time scale in quasifission reactions

    Energy Technology Data Exchange (ETDEWEB)

    Back, B.B.; Paul, P.; Nestler, J. [and others

    1995-08-01

    The quasifission process arises from the hindrance of the complete fusion process when heavy-ion beams are used. The strong dissipation in the system tends to prevent fusion and lead the system towards reseparation into two final products of similar mass reminiscent of a fission process. This dissipation slows down the mass transfer and shape transformation and allows for the emission of high energy {gamma}-rays during the process, albeit with a low probability. Giant Dipole {gamma} rays emitted during this time have a characteristic spectral shape and may thus be discerned in the presence of a background of {gamma} rays emitted from the final fission-like fragments. Since the rate of GDR {gamma} emission is very well established, the strength of this component may therefore be used to measure the timescale of the quasifission process. In this experiment we studied the reaction between 368-MeV {sup 58}Ni and a {sup 165}Ho target, where deep inelastic scattering and quasifission processes are dominant. Coincidences between fission fragments (detected in four position-sensitive avalanche detectors) and high energy {gamma} rays (measured in a 10{close_quotes} x 10{close_quotes} actively shielded NaI detector) were registered. Beams were provided by the Stony Brook Superconducting Linac. The {gamma}-ray spectrum associated with deep inelastic scattering events is well reproduced by statistical cooling of projectile and target-like fragments with close to equal initial excitation energy sharing. The y spectrum associated with quasifission events is well described by statistical emission from the fission fragments alone, with only weak evidence for GDR emission from the mono-nucleus. A 1{sigma} limit of t{sub ss} < 11 x 10{sup -21} s is obtained for the mono-nucleus lifetime, which is consistent with the lifetime obtained from quasifission fragment angular distributions. A manuscript was accepted for publication.

  10. Intermediate processes in nuclear reactions

    International Nuclear Information System (INIS)

    Petrovici, M.

    1983-01-01

    The main results presented here cannot be interpreted in terms of the direct reaction model or the statistical models and one can more or less explicitely use some nuclear configurations for their interpretation. The first chapter deals with the so-called second order intermediate structures observed in the elastic and inelastic proton scattering on 66 Zn and 70 Ge targets in the energetic regions of some isobaric analog resonances. A formal theory for their interpretation is developed and the comparison with the experimental data is presented. New experimental results on the resonant structures observed in the elastic and inelastic scattering of 12 C on 24 Mg are presented in the second chapter. Detailed statistical analysis and their interpretation is presented too. Charge equilibration in deep inelastic collisions is the main subject of the third chapter. The experimental results obtained by the 98 Mo + 154 Sm collision at 12 MeV/n, a quantum treatment of a damped harmonic oscillator and the comparison with the experimental data are given. In the last chapter, some results on the existence of two other processes which could candidate to be involved in the main topic are presented. Those processes are: the fast fragmentation and preequilibrium charged particles emission. All these processes originate in the excitation of some simple configurations which can be seen on ''doorway'' states (''Hallway'' in the case of the second intermediate structures). The coupling of these states to other more complicated excitation modes of the nuclei and to outgoing channel=gives the possibility to study the nuclear dynamics. This justifies the interest for their detailed theoretical and experimental investigations. (author)

  11. Evaluation of periprocedural hypersensitivity reactions.

    Science.gov (United States)

    Iammatteo, Melissa; Keskin, Taha; Jerschow, Elina

    2017-10-01

    Identifying the cause of periprocedural hypersensitivity reactions (HSRs) remains challenging because of the multitude of medications involved. Antibiotics are the most common cause in the United States, whereas neuromuscular blocking agents are most common in Europe. To identify causative agents for periprocedural HSRs. This study was a 7-year retrospective medical record review of patients evaluated between December 2009 and January 2017 at a drug allergy center in Bronx, New York for periprocedural HSRs, defined as occurring soon before, during, or soon after a medical procedure or operation with or without general anesthesia. Demographics, description of historical HSRs, results of testing to potential causative medications, and tolerance of subsequent anesthesia were reviewed. Thirty-four patients completed a comprehensive evaluation. Skin testing identified an IgE-mediated cause in 22 patients (64.7%). The most common causative class of medications was induction agents (n = 9 [36%]), with midazolam being the most frequently implicated (n = 6 [3 positive skin test results, 3 equivocal skin test results]). Cefazolin was the most common agent identified (n = 8 [32%]) followed by ondansetron (n = 3 [12%]). Sixteen of 22 contacted patients were exposed to subsequent anesthesia, including 3 patients with negative evaluations. One patient experienced a mild urticarial HSR. Induction agents were the most common causative agents in our patients, which differs from other studies. Given the variability in evaluations of periprocedural HSRs across the United States with data published on small sample sizes, there is a need to establish national guidelines to standardize evaluations and to create a national registry to allow for data sharing. Copyright © 2017 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  12. Catalytic Hydrogenation Reaction of Naringin-Chalcone. Study of the Electrochemical Reaction

    Directory of Open Access Journals (Sweden)

    B. A. López de Mishima

    2000-03-01

    Full Text Available The electrocatalytic hydrogenation reaction of naringin derivated chalcone is studied. The reaction is carried out with different catalysts in order to compare with the classic catalytic hydrogenation.

  13. Entity models for trigger-reaction documents

    NARCIS (Netherlands)

    Khalid, M.A.; Marx, M.; Makkes, M.X.

    2008-01-01

    We define the notion of an entity model for a special kind of document popular on the web: an article followed by a list of reactions on that article, usually by many authors, usually inverse chronologically ordered. We call these documents trigger-reactions pairs. The entity model describes which

  14. Reaction between drug substances and pharmaceutical excipients

    DEFF Research Database (Denmark)

    Larsen, Jesper; Cornett, Claus; Jaroszewski, Jerzy Witold

    2009-01-01

    The reactivity of citric acid towards drug substances in the solid state was examined using the beta-blocker carvedilol as a model compound. The reaction mixtures were analysed by LC-MS, the reaction products were isolated by preparative HPLC, and the structures were elucidated by microprobe NMR...

  15. Enantioselective solvent-free Robinson annulation reactions

    Indian Academy of Sciences (India)

    Unknown

    asymmetric annulation reactions in a solid–liquid phase reaction in the absence of solvents to effect an asymmetric synthesis is an important step forward towards cleaner synthesis 2. Environmental and economic pressures are now forcing the chemical community to search for more efficient ways of performing chemical ...

  16. Reactions to Stranger and Acquaintance Rape.

    Science.gov (United States)

    Tetreault, Patricia A.; Barnett, Mark A.

    1987-01-01

    Investigated reactions to a woman who presumably had been raped by a stranger or an acquaintance. Undergraduates read one of two rape descriptions prior to watching a videotape of the woman who (they were led to believe) had been the victim of the rape. Females and males showed markedly different reactions to stranger and acquaintance rape and…

  17. Rape: The Husband's and Boyfriend's Intital Reactions.

    Science.gov (United States)

    Holmstrom, Lynda Lytle; Burgess, Wolbert

    1979-01-01

    Analyzes the reaction of husbands and boyfriends to the rape of a wife or girlfriend. The man's reaction has two components: his own response and his interaction with the victim. The issues are whether the couple can discuss the rape, deal with the woman's new phobias, and resume sexual relations. (Author)

  18. The Theory of Absolute Reaction Rates

    Indian Academy of Sciences (India)

    Admin

    ... theory overcame all obstacles and is presently the most successful theory for chemical reactions. The Classic in this issue is the paper by Eyring, presented at this meeting. It summarizes the contributions of his group till that date, and is one of the most important papers in the theory of chemical reactions. K L Sebastian ...

  19. Review of fungus-induced asthmatic reactions

    NARCIS (Netherlands)

    Kauffman, H. F.; TOMEE, J. F.; van der Werf, T. S.; de Monchy, J. G.; Koëter, G. K.

    Fungus-induced obstructive airway disease in atopic individuals can be differentiated into two categories: first, uncomplicated asthmatic reactions due to high but transient exposure to fungal spores (fungal asthma), resulting in a T-H2-type response with immunoglobulin E-mediated reactions and

  20. Femtosecond laser control of chemical reactions

    CSIR Research Space (South Africa)

    Du Plessis, A

    2010-08-31

    Full Text Available Femtosecond laser control of chemical reactions is made possible through the use of pulse-shaping techniques coupled to a learning algorithm feedback loop – teaching the laser pulse to control the chemical reaction. This can result in controllable...

  1. Rebinding in biochemical reactions on membranes

    Science.gov (United States)

    Lawley, Sean D.; Keener, James P.

    2017-10-01

    The behavior of many biochemical processes depends crucially on molecules rapidly rebinding after dissociating. In the case of multisite protein modification, the importance of rebinding has been demonstrated both experimentally and through several recent computational studies involving stochastic spatial simulations. As rebinding stems from spatio-temporal correlations, theorists have resorted to models that explicitly include space to properly account for the effects of rebinding. However, for reactions in three space dimensions it was recently shown that well-mixed ordinary differential equation (ODE) models can incorporate rebinding by adding connections to the reaction network. The rate constants for these new connections involve the probability that a pair of molecules rapidly rebinds after dissociation. In order to study biochemical reactions on membranes, in this paper we derive an explicit formula for this rebinding probability for reactions in two space dimensions. We show that ODE models can use the formula to replicate detailed stochastic spatial simulations, and that the formula can predict ultrasensitivity for reactions involving multisite modification of membrane-bound proteins. Further, we compute a new concentration-dependent rebinding probability for reactions in three space dimensions. Our analysis predicts that rebinding plays a much larger role in reactions on membranes compared to reactions in cytoplasm.

  2. Strategies for Innovation in Multicomponent Reaction Design

    OpenAIRE

    Ganem, Bruce

    2009-01-01

    By generating structural complexity in a single step from three or more reactants, multicomponent reactions (MCRs) make it possible to synthesize target compounds with greater efficiency and atom economy. The history of such reactions can be traced to the mid-nineteenth century when Strecker first produced α-aminonitriles from the condensation of aldehydes with ammonia and hydrogen cyanide.

  3. Multicomponent Reactions, Union of MCRs and Beyond

    NARCIS (Netherlands)

    Zarganes-Tzitzikas, Tryfon; Chandgude, Ajay L; Dömling, Alexander

    2015-01-01

    Multicomponent reactions (MCRs), which are located between one- and two-component and polymerization reactions, provide a number of valuable conceptual and synthetic advantages over stepwise sequential approaches towards complex and valuable molecules. To address current limitations in the number of

  4. Analytical Study of Thermonuclear Reaction Probability Integrals

    OpenAIRE

    Chaudhry, M. A.; Haubold, H. J.; Mathai, A. M.

    2000-01-01

    An analytic study of the reaction probability integrals corresponding to the various forms of the slowly varying cross-section factor $S(E)$ is attempted. Exact expressions for reaction probability integrals are expressed in terms of the extended gamma functions.

  5. Parity violation in neutron induced reactions

    International Nuclear Information System (INIS)

    Gudkov, V.P.

    1991-06-01

    The theory of parity violation in neutron induced reactions is discussed. Special attention is paid to the energy dependence and enhancement factors for the various types of nuclear reactions and the information which might be obtained from P-violating effects in nuclei. (author)

  6. Immune reactions in classical Hodgkin's lymphoma

    NARCIS (Netherlands)

    Poppema, S; Potters, M; Emmens, R; Visser, L; van den Berg, A.

    The immune reaction in classical Hodgkin's lymphoma (HL) can be separated into an inflammatory response in the involved tissues and a generalized immune response in the patient. The local immune reaction in HL is by far the most prominent among all tumors, with the exception of so called T-cell-rich

  7. Chemical Reaction: Diagnosis and Towards Remedy of ...

    African Journals Online (AJOL)

    Experience and literature show that most high school students do not have the correct mental models of coefficients and subscripts in chemical reactions. To contribute towards the conceptual reconstruction of scientific mental models of coefficients and subscripts in a chemical reaction a new teaching-learning strategy is ...

  8. reactions of enolisable ketones with dichloroisocyanuric acid

    African Journals Online (AJOL)

    B. S. Chandravanshi

    1Department of Chemistry, TJPS (PG) College, Guntur-522006, India .... Reactions of enolisable ketones with dichloroisocyanuric acid. Bull. Chem. Soc. Ethiop. 2015, 29(1). 131. Figure 2. Plots for first order dependence on oxidant (in ..... Subba Rao, T.L.M.V. Study of chemical dynamics of some oxidation reactions, Ph.D.

  9. Potential energy surfaces for chemical reactions

    International Nuclear Information System (INIS)

    Schaefer, H.F. III.

    1976-01-01

    Research into potential energy surfaces for chemical reactions at Lawrence Berkeley Laboratory during 1976 is described. Topics covered include: the fuzzy interface between surface chemistry catalysis and organometallic chemistry; potential energy surfaces for elementary fluorine hydrogen reactions; structure, energetics, and reactivity of carbenes; and the theory of self-consistent electron pairs

  10. Spallation reactions studied with 4-detector arrays

    Indian Academy of Sciences (India)

    Recently there has been a renewed interest in the study of spallation reactions in basic nuclear physics as well as in potential applications. Spallation reactions induced by light projectiles (protons, antiprotons, pions, etc.) in the GeV range allow the formation of hot nuclei which do not suffer the collective excitations ...

  11. Heavy ion reactions at low energies

    International Nuclear Information System (INIS)

    Nemes, M.C.

    1985-01-01

    Some general features of the heavy ion reactions at low energies are presented. Some kinds of processes are studied, such as: elastic scattering, peripherical reactions, deep inelastic collisions and fusion. Both, theoretical and experimental perspectives on this field are discussed. (L.C.) [pt

  12. Adverse reactions to intravascularly administered contrast media

    International Nuclear Information System (INIS)

    Olin, T.

    1986-01-01

    A hypothesis is formulated about the mechanisms causing adverse reactions to contrast media. Contrast media act in two ways. They stimulate the mast cells to release histamine and leukotrienes, and they inhibit the enzymes which otherwise degrade leukotrienes. Thus individuals, especially those with a history of allergy, are easily exposed to undue amounts of leukotrienes and these are responsible for the adverse reactions. (orig.)

  13. Multicomponent modelling of Portland cement hydration reactions

    NARCIS (Netherlands)

    Ukrainczyk, N.; Koenders, E.A.B.; Van Breugel, K.

    2012-01-01

    The prospect of cement and concrete technologies depends on more in depth understanding of cement hydration reactions. Hydration reaction models simulate the development of the microstructures that can finally be used to estimate the cement based material properties that influence performance and

  14. Chemical reaction due to stronger Ramachandran interaction

    Indian Academy of Sciences (India)

    fulfilling this condition, these atoms still need to have an overall strong attractive interaction (either before or after the collision) to form the required transition state. For example, the transition state by definition gives equal probability for the reaction to go either way (to form reactant atoms, or the reaction product). There-.

  15. Organotellurium ligands–designing and complexation reactions

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 114; Issue 4. Organotellurium ligands - designing and complexation reactions. Ajai K Singh. Volume 114 Issue 4 August ... A variety of tellurium ligands has been designed and studied for their complexation reactions in the last decade. Of these hybrid telluroethers, ...

  16. Reactions the private life of atoms

    CERN Document Server

    Atkins, Peter

    2011-01-01

    Through an innovative, closely integrated design of images and text, and his characteristically clear, precise, and economical exposition, Peter Atkins explains the processes involved in chemical reactions. He begins by introducing a 'tool kit' of basic reactions, such as precipitation, corrosion, and catalysis, and concludes by showing how these building blocks are brought together in more complex processes such as photosynthesis.

  17. Heavy ion transfer reactions: Status and perspectives

    Indian Academy of Sciences (India)

    Abstract. With the large solid angle magnetic spectrometer (PRISMA) coupled to the γ-array (CLARA), extensive investigations of nuclear structure and reaction dynamics have been carried out. In the present paper aspects of these studies will be presented, focussing more closely on the reaction mechanism, in particular on ...

  18. Hydrazine in the Ugi Tetrazole Reaction

    NARCIS (Netherlands)

    Patil, Pravin; Zhang, Ji; Kurpiewska, Katarzyna; Kalinowska-Tłuścik, Justyna; Dömling, Alexander

    2016-01-01

    We describe the hitherto unknown use of N-Boc-protected hydrazine in the Ugi tetrazole reaction to access a library of highly substituted 5-(hydrazinomethyl)-1-methyl-1H-tetrazoles. The reaction is very versatile and good to high yielding. A one-pot, two-step procedure is given.

  19. Entropy Generation in a Chemical Reaction

    Science.gov (United States)

    Miranda, E. N.

    2010-01-01

    Entropy generation in a chemical reaction is analysed without using the general formalism of non-equilibrium thermodynamics at a level adequate for advanced undergraduates. In a first approach to the problem, the phenomenological kinetic equation of an elementary first-order reaction is used to show that entropy production is always positive. A…

  20. Use of Isotopes for Studying Reaction Mechanisms

    Indian Academy of Sciences (India)

    applications of isotopic substitution for studying reaction mechanisms and dynamic structures. Suggested Reading. • B K Carpenter. Determination of Organic Reaction Mechanisms. John. Wiley. New York, 1984. • F A Carey and R J Sundberg. Advanced Organic Chemistry. Part A. 3rd. Ed. Plenum Press. New York, 1990.

  1. Infliximab-Related Infusion Reactions: Systematic Review

    Science.gov (United States)

    Ron, Yulia; Kivity, Shmuel; Ben-Horin, Shomron; Israeli, Eran; Fraser, Gerald M.; Dotan, Iris; Chowers, Yehuda; Confino-Cohen, Ronit; Weiss, Batia

    2015-01-01

    Objective: Administration of infliximab is associated with a well-recognised risk of infusion reactions. Lack of a mechanism-based rationale for their prevention, and absence of adequate and well-controlled studies, has led to the use of diverse empirical administration protocols. The aim of this study is to perform a systematic review of the evidence behind the strategies for preventing infusion reactions to infliximab, and for controlling the reactions once they occur. Methods: We conducted extensive search of electronic databases of MEDLINE [PubMed] for reports that communicate various aspects of infusion reactions to infliximab in IBD patients. Results: We examined full texts of 105 potentially eligible articles. No randomised controlled trials that pre-defined infusion reaction as a primary outcome were found. Three RCTs evaluated infusion reactions as a secondary outcome; another four RCTs included infusion reactions in the safety evaluation analysis; and 62 additional studies focused on various aspects of mechanism/s, risk, primary and secondary preventive measures, and management algorithms. Seven studies were added by a manual search of reference lists of the relevant articles. A total of 76 original studies were included in quantitative analysis of the existing strategies. Conclusions: There is still paucity of systematic and controlled data on the risk, prevention, and management of infusion reactions to infliximab. We present working algorithms based on systematic and extensive review of the available data. More randomised controlled trials are needed in order to investigate the efficacy of the proposed preventive and management algorithms. PMID:26092578

  2. Catalysis and Multi-Component Reactions

    Science.gov (United States)

    Shibasaki, Masakatsu; Yus, Miguel; Bremner, Stacy; Comer, Eamon; Shore, Gjergji; Morin, Sylvie; Organ, Michael G.; van der Eycken, Erik; Merkul, Eugen; Dorsch, Dieter; Müller, Thomas J. J.; Ryabukhin, Sergey V.; Ostapchuk, Eugeniy N.; Plaskon, Andrey S.; Volochnyuk, Dmitriy M.; Shivanyuk, Alexander N.; Tolmachev, Andrey A.; Sheibani, Hassan; Babaie, Maryam; Behzadi, Soheila; Dabiri, Minoo; Bahramnejad, Mahboobeh; Bashiribod, Sahareh; Hekmatshoar, Rahim; Sadjadi, Sodeh; Khorasani, Mohammad; Polyakov, Anatoliy I.; Eryomina, Vera A.; Medvedeva, Lidiya A.; Tihonova, Nadezhda I.; Listratova, Anna V.; Voskressensky, Leonid G.; Merkul, Eugen; Dorsch, Dieter; Müller, Thomas J. J.; Sheibani, Hassan; Esfandiarpoor, Zeinab; Behzadi, Soheila; Titova, Julia A.; Fedorova, Olga V.; Ovchinnikova, Irina G.; Valova, Marina S.; Koryakova, Olga V.; Rusinov, Gennady L.; Charushin, Valery N.; Hekmatshoar, Rahim; Sadjadi, Sodeh

    We have been studying the development of new asymmetric two-center catalysis using rare earth alkoxides and bifunctional sugar and related ligands. In The Fourth International Conference on Multi-Component Reactions and Related Chemistry (MCR 2009), new catalytic asymmetric reactions using catalysts 1 and 2 and catalytic asymmetric syntheses of ranirestat 3 and tamiflu 4 will be presented.

  3. Chemical Principles Revisited: Annotating Reaction Equations.

    Science.gov (United States)

    Tykodi, R. J.

    1987-01-01

    Urges chemistry teachers to have students annotate the chemical reactions in aqueous-solutions that they see in their textbooks and witness in the laboratory. Suggests this will help students recognize the reaction type more readily. Examples are given for gas formation, precipitate formation, redox interaction, acid-base interaction, and…

  4. TRIMOLECULAR REACTIONS OF URANIUM HEXAFLUORIDE WITH WATER

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, M.; Becnel, J.; Garrison, S.

    2010-02-25

    The hydrolysis reaction of uranium hexafluoride (UF{sub 6}) is a key step in the synthesis of uranium dioxide (UO{sub 2}) powder for nuclear fuels. Mechanisms for the hydrolysis reactions are studied here with density functional theory and the Stuttgart small-core scalar relativistic pseudopotential and associated basis set for uranium. The reaction of a single UF{sub 6} molecule with a water molecule in the gas phase has been previously predicted to proceed over a relatively sizeable barrier of 78.2 kJ {center_dot} mol{sup -1}, indicating this reaction is only feasible at elevated temperatures. Given the observed formation of a second morphology for the UO{sub 2} product coupled with the observations of rapid, spontaneous hydrolysis at ambient conditions, an alternate reaction pathway must exist. In the present work, two trimolecular hydrolysis mechanisms are studied with density functional theory: (1) the reaction between two UF{sub 6} molecules and one water molecule, and (2) the reaction of two water molecules with a single UF{sub 6} molecule. The predicted reaction of two UF{sub 6} molecules with one water molecule displays an interesting 'fluorine-shuttle' mechanism, a significant energy barrier of 69.0 kJ {center_dot} mol{sup -1} to the formation of UF{sub 5}OH, and an enthalpy of reaction ({Delta}H{sub 298}) of +17.9 kJ {center_dot} mol{sup -1}. The reaction of a single UF{sub 6} molecule with two water molecules displays a 'proton-shuttle' mechanism, and is more favorable, having a slightly lower computed energy barrier of 58.9 kJ {center_dot} mol{sup -1} and an exothermic enthalpy of reaction ({Delta}H{sub 298}) of -13.9 kJ {center_dot} mol{sup -1}. The exothermic nature of the overall UF{sub 6} + 2 {center_dot} H{sub 2}O trimolecular reaction and the lowering of the barrier height with respect to the bimolecular reaction are encouraging; however, the sizable energy barrier indicates further study of the UF{sub 6} hydrolysis reaction

  5. Selective immediate hypersensitivity reactions to NSAIDs.

    Science.gov (United States)

    Canto, Maria Gabriela; Andreu, Isabel; Fernandez, Javier; Blanca, Miguel

    2009-08-01

    Selective immediate reactions to NSAIDs imply that patients develop a urticarial/anaphylactic response to a single drug with good tolerance to other compounds. No systematic review of these reactions has yet been made. With the increase in consumption of NSAIDs, these have become one of the most common drugs inducing hypersensitivity reactions. Although cross-intolerance reactions are the most common, a significant proportion is selective responses. As specific IgE antibodies are not always found, there is only indirect evidence supporting an IgE-mediated mechanism in selective NSAID reactors. Selective immediate reactions to NSAIDs must be considered when a patient develops urticaria or anaphylaxis after intake of one drug with good tolerance to drugs from other groups or even a drug from the same group with a slightly different chemical structure. Further research is required to identify the antigenic determinant structures recognized.

  6. Constituent models and large transverse momentum reactions

    International Nuclear Information System (INIS)

    Brodsky, S.J.

    1975-01-01

    The discussion of constituent models and large transverse momentum reactions includes the structure of hard scattering models, dimensional counting rules for large transverse momentum reactions, dimensional counting and exclusive processes, the deuteron form factor, applications to inclusive reactions, predictions for meson and photon beams, the charge-cubed test for the e/sup +-/p → e/sup +-/γX asymmetry, the quasi-elastic peak in inclusive hadronic reactions, correlations, and the multiplicity bump at large transverse momentum. Also covered are the partition method for bound state calculations, proofs of dimensional counting, minimal neutralization and quark--quark scattering, the development of the constituent interchange model, and the A dependence of high transverse momentum reactions

  7. Catalytic Conia-ene and related reactions.

    Science.gov (United States)

    Hack, Daniel; Blümel, Marcus; Chauhan, Pankaj; Philipps, Arne R; Enders, Dieter

    2015-10-07

    Since its initial inception, the Conia-ene reaction, known as the intramolecular addition of enols to alkynes or alkenes, has experienced a tremendous development and appealing catalytic protocols have emerged. This review fathoms the underlying mechanistic principles rationalizing how substrate design, substrate activation, and the nature of the catalyst work hand in hand for the efficient synthesis of carbocycles and heterocycles at mild reaction conditions. Nowadays, Conia-ene reactions can be found as part of tandem reactions, and the road for asymmetric versions has already been paved. Based on their broad applicability, Conia-ene reactions have turned into a highly appreciated synthetic tool with impressive examples in natural product synthesis reported in recent years.

  8. Mechanisms of inorganic and organometallic reactions

    CERN Document Server

    The purpose of this series is to provide a continuing critical review of the literature concerned with mechanistic aspects of inorganic and organo­ metallic reactions in solution, with coverage being complete in each volume. The papers discussed are selected on the basis of relevance to the elucidation of reaction mechanisms and many include results of a nonkinetic nature when useful mechanistic information can be deduced. The period of literature covered by this volume is July 1982 through December 1983, and in some instances papers not available for inclusion in the previous volume are also included. Numerical results are usually reported in the units used by the original authors, except where data from different papers are com­ pared and conversion to common units is necessary. As in previous volumes material included covers the major areas of redox processes, reactions of the nonmetallic elements, reaction of inert and labile metal complexes and the reactions of organometallic compounds. While m...

  9. Low energy ion-molecule reactions

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, J.M. [Univ. of Rochester, NY (United States)

    1993-12-01

    This project is concerned with elucidating the dynamics of elementary ion-molecule reactions at collision energies near and below 1 eV. From measurements of the angular and energy distributions of the reaction products, one can infer intimathe details about the nature of collisions leading to chemical reaction, the geometries and lifetimes of intermediate complexes that govern the reaction dynamics, and the collision energy dependence of these dynamical features. The author employs crossed-beam low energy mass spectrometry technology developed over the last several years, with the focus of current research on proton transfer and hydrogen atom transfer reactions of te O{sup {minus}} ion with species such as HF, H{sub 2}O, and NH{sub 3}.

  10. Snake antivenoms: adverse reactions and production technology

    Directory of Open Access Journals (Sweden)

    VM Morais

    2009-01-01

    Full Text Available Antivenoms have been widely used for more than a century for treating snakebites and other accidents with poisonous animals. Despite their efficacy, the use of heterologous antivenoms involves the possibility of adverse reactions due to activation of the immune system. In this paper, alternatives for antivenom production already in use were evaluated in light of their ability to minimize the occurrence of adverse reactions. These effects were classified according to their molecular mechanism as: anaphylactic reactions mediated by IgE, anaphylactoid reactions caused by complement system activation, and pyrogenic reactions produced mainly by the presence of endotoxins in the final product. In the future, antivenoms may be replaced by humanized antibodies, specific neutralizing compounds or vaccination. Meanwhile, improvements in antivenom quality will be focused on the obtainment of a more purified and specific product in compliance with good manufacturing practices and at an affordable cost.

  11. Intramolecular and Transannular Diels-Alder Reactions

    DEFF Research Database (Denmark)

    Tanner, David Ackland; Ascic, Erhad

    2014-01-01

    Few reactions can compete with the Diels-Alder (DA) [4+2] cycloaddition for the rapid and efficient generation of molecular complexity. The DA reaction is atom-economic and stereospecific, as well as diastereo- and regioselective. The intramolecular version (IMDA) of the DA cycloaddition and its...... and dienophile, methods for acceleration of IMDA reactions (such as use of high pressure) and catalysis (using oxophilic or carbophilic metal complexes, Brønsted acids, and enzymes). The use of furans as diene components (IMDAF), intramolecular hetero-DA (IMHDA) and IMDA reactions with inverse electron demand...... are also covered. Applications of IMDA to asymmetric synthesis (from substrate control through to enantioselective catalysis, including organocatalysis) are presented, along with tandem sequences involving IMDA cycloaddition. A theme pervading the whole chapter is the use of IMDA reactions for the total...

  12. Nature-Inspired Chemical Reaction Optimisation Algorithms.

    Science.gov (United States)

    Siddique, Nazmul; Adeli, Hojjat

    2017-01-01

    Nature-inspired meta-heuristic algorithms have dominated the scientific literature in the areas of machine learning and cognitive computing paradigm in the last three decades. Chemical reaction optimisation (CRO) is a population-based meta-heuristic algorithm based on the principles of chemical reaction. A chemical reaction is seen as a process of transforming the reactants (or molecules) through a sequence of reactions into products. This process of transformation is implemented in the CRO algorithm to solve optimisation problems. This article starts with an overview of the chemical reactions and how it is applied to the optimisation problem. A review of CRO and its variants is presented in the paper. Guidelines from the literature on the effective choice of CRO parameters for solution of optimisation problems are summarised.

  13. Ultracold 4-center reactions of KRb molecules

    Science.gov (United States)

    Hu, Ming-Guang; Liu, Yu; Gheorghe, Andrei; Lin, Yen-Wei; Ni, Kang-Kuen

    2017-04-01

    Chemical reactions at the fundamental level obey the laws of quantum mechanics. However, reactions are often far from the regime where the quantum motions of the reagents play an important role. Ultracold reactions of KRb is a good candidate, where the unusual 4-center reactions between two KRb molecules is expected to produce K2 and Rb2 molecules with 10 cm-1 (or 14.4 K) excess energy. To directly measure reaction products and to fully map out their quantum states, we are designing and constructing a novel quantum degenerate gas apparatus with the integration of REMPI and ion velocity mapping imaging. Our work aims to open up new directions for physical chemistry studies with AMO techniques.

  14. [Allergic reaction during anesthesia: two case reports].

    Science.gov (United States)

    Okamoto, Shinji; Futagawa, Koichi; Sugiura, Junko; Uchida, Tomohisa; Okuda, Takahiko; Koga, Yoshihisa

    2009-10-01

    We experienced two cases of serious and potentially life-threatening allergic reactions. The first patient was a 28-year-old male patient scheduled for surgery for cerebral arteriovenous malformations and another patient was a 66-year-old male patient scheduled for hepatic resection. After uneventful anesthetic induction, anesthesia was maintained with sevoflurane, air and oxygen. Both patients developed allergic reactions characterized by cardiovascular failure during anesthesia. Resuscitative treatment included rapid fluid infusion, administration of adrenaline and steroid. Both patients were successfully resuscitated without any lasting sequelae. The causative agent in one of these cases was probably a prophylactically used antibiotic, while that of the other case was a reaction to latex. Both patients showed elevated histamine and tryptase concentrations in blood samples. Recently, the incidence of allergic reactions to antibiotics and latex during anesthesia is increasing. Anesthesiologists should, therefore, be aware of the possibility of allergic reactions to all drugs and substances, especially to latex, during the perioperative period.

  15. Cascade enzymatic reactions for efficient carbon sequestration.

    Science.gov (United States)

    Xia, Shunxiang; Zhao, Xueyan; Frigo-Vaz, Benjamin; Zheng, Wenyun; Kim, Jungbae; Wang, Ping

    2015-04-01

    Thermochemical processes developed for carbon capture and storage (CCS) offer high carbon capture capacities, but are generally hampered by low energy efficiency. Reversible cascade enzyme reactions are examined in this work for energy-efficient carbon sequestration. By integrating the reactions of two key enzymes of RTCA cycle, isocitrate dehydrogenase and aconitase, we demonstrate that intensified carbon capture can be realized through such cascade enzymatic reactions. Experiments show that enhanced thermodynamic driving force for carbon conversion can be attained via pH control under ambient conditions, and that the cascade reactions have the potential to capture 0.5 mol carbon at pH 6 for each mole of substrate applied. Overall it manifests that the carbon capture capacity of biocatalytic reactions, in addition to be energy efficient, can also be ultimately intensified to approach those realized with chemical absorbents such as MEA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Nuclear Reaction Data File for Astrophysics (NRDF/A) in Hokkaido University Nuclear Reaction Data Center

    International Nuclear Information System (INIS)

    Kato, Kiyoshi; Kimura, Masaaki; Furutachi, Naoya; Makinaga, Ayano; Togashi, Tomoaki; Otuka, Naohiko

    2010-01-01

    The activities of the Japan Nuclear Reaction Data Centre is explained. The main task of the centre is data compilation of Japanese nuclear reaction data in collaboration of the International Network of Nuclear Reaction Data Centres. As one of recent activities, preparation of a new database (NRDF/A) and evaluation of astronuclear reaction data are reported. Collaboration in the nuclear data activities among Asian countries is proposed.

  17. Comparison of DSMC Reaction Models with QCT Reaction Rates for Nitrogen

    Science.gov (United States)

    2016-07-17

    include area code) N/A Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. 239.18 Comparison of DSMC Reaction Models with QCT Reaction Rates ...controls vibration coupling A is adjusted to match thermal reaction rate Simplest to implement, not tied to any other model Distribution A: Approved for...General trend: reaction rate increases with v • TCE, QK: lack of vibrational favoring results in much lower slope as compared to the benchmark QCT • VFD: φ

  18. The dynamics of the Hg + Br2 reaction: elucidation of the reaction mechanism for the Br exchange reaction.

    Science.gov (United States)

    Jambrina, P G; Menéndez, M; Aoiz, F J

    2017-06-28

    In spite of its importance in the Hg atmospheric chemistry, the dynamics of the Hg + Br 2 → HgBr + Br reaction is poorly understood. In this article, we have carried out a comprehensive study of the reaction mechanism of this reaction by means of quasiclassical trajectories (QCTs) on an existing ab initio potential energy surface (PES). The reaction has a non trivial dynamics, as a consequence of its large endothermicity, the presence of a deep potential well, and the competition between the Br exchange and the collision induced dissociation processes. Our calculations demonstrate that insertion is only relevant at energies just above the reaction threshold and that, at energies above 2.3 eV, HgBr formation typically takes place via a sort of frustrated dissociation. In order to compare directly with the results obtained in extensive cross molecular beam experiments for the homologous reaction with I 2 , angular distributions in the laboratory frame for Hg + Br 2 have been simulated under similar experimental conditions. The lack of agreement at the highest energies considered suggests that either the two reactions have substantially different mechanisms or that calculations on a single PES cannot account for the dynamics at those energies.

  19. Connecting localized DNA strand displacement reactions

    Science.gov (United States)

    Mullor Ruiz, Ismael; Arbona, Jean-Michel; Lad, Amitkumar; Mendoza, Oscar; Aimé, Jean-Pierre; Elezgaray, Juan

    2015-07-01

    Logic circuits based on DNA strand displacement reactions have been shown to be versatile enough to compute the square root of four-bit numbers. The implementation of these circuits as a set of bulk reactions faces difficulties which include leaky reactions and intrinsically slow, diffusion-limited reaction rates. In this paper, we consider simple examples of these circuits when they are attached to platforms (DNA origamis). As expected, constraining distances between DNA strands leads to faster reaction rates. However, it also induces side-effects that are not detectable in the solution-phase version of this circuitry. Appropriate design of the system, including protection and asymmetry between input and fuel strands, leads to a reproducible behaviour, at least one order of magnitude faster than the one observed under bulk conditions.Logic circuits based on DNA strand displacement reactions have been shown to be versatile enough to compute the square root of four-bit numbers. The implementation of these circuits as a set of bulk reactions faces difficulties which include leaky reactions and intrinsically slow, diffusion-limited reaction rates. In this paper, we consider simple examples of these circuits when they are attached to platforms (DNA origamis). As expected, constraining distances between DNA strands leads to faster reaction rates. However, it also induces side-effects that are not detectable in the solution-phase version of this circuitry. Appropriate design of the system, including protection and asymmetry between input and fuel strands, leads to a reproducible behaviour, at least one order of magnitude faster than the one observed under bulk conditions. Electronic supplementary information (ESI) available. See DOI: 10.1039/C5NR02434J

  20. Electrode reactions in slowly relaxing media

    Science.gov (United States)

    Matyushov, Dmitry V.; Newton, Marshall D.

    2017-11-01

    Standard models of reaction kinetics in condensed materials rely on the Boltzmann-Gibbs distribution for the population of reactants at the top of the free energy barrier separating them from the products. While energy dissipation and quantum effects at the barrier top can potentially affect the transmission coefficient entering the rate pre-exponential factor, much stronger dynamical effects on the reaction barrier are caused by the breakdown of ergodicity for populating the reaction barrier (violation of the Boltzmann-Gibbs statistics). When the spectrum of medium modes coupled to the reaction coordinate includes fluctuations slower than the reaction rate, such nuclear motions dynamically freeze on the reaction time scale and do not contribute to the activation barrier. Here we consider the consequences of this scenario for electrode reactions in slowly relaxing media. Changing the electrode overpotential speeds the electrode electron transfer up, potentially cutting through the spectrum of nuclear modes coupled to the reaction coordinate. The reorganization energy of electrochemical electron transfer becomes a function of the electrode overpotential, switching between the thermodynamic value at low rates to the nonergodic limit at higher rates. The sharpness of this transition depends on the relaxation spectrum of the medium. The reorganization energy experiences a sudden drop with increasing overpotential for a medium with a Debye relaxation but becomes a much shallower function of the overpotential for media with stretched exponential dynamics. The latter scenario characterizes the electron transfer in ionic liquids. The analysis of electrode reactions in room-temperature ionic liquids shows that the magnitude of the free energy of nuclear solvation is significantly below its thermodynamic limit. This result applies to reaction times faster than microseconds and is currently limited by the available dielectric relaxation data.

  1. The quantum normal form approach to reactive scattering : The cumulative reaction probability for collinear exchange reactions

    NARCIS (Netherlands)

    Goussev, Arseni; Schubert, Roman; Waalkens, Holger; Wiggins, Stephen

    2009-01-01

    The quantum normal form approach to quantum transition state theory is used to compute the cumulative reaction probability for collinear exchange reactions. It is shown that for heavy-atom systems such as the nitrogen-exchange reaction, the quantum normal form approach gives excellent results and

  2. Effect of Reaction Developing Training on Audio-Visual Feet Reaction Time in Wrestlers

    Science.gov (United States)

    Kaya, Mustafa

    2016-01-01

    Reaction time is one of the most determinative elements for a successful sports performance. The purpose of this study was to investigate the effect of 12-week feet reaction developing trainings upon feet reaction time of females at 11-13 age interval. Volunteer sportsmen between 11 and 13 age interval who were active in Tokat Provincial…

  3. Model Experiment of Thermal Runaway Reactions Using the Aluminum-Hydrochloric Acid Reaction

    Science.gov (United States)

    Kitabayashi, Suguru; Nakano, Masayoshi; Nishikawa, Kazuyuki; Koga, Nobuyoshi

    2016-01-01

    A laboratory exercise for the education of students about thermal runaway reactions based on the reaction between aluminum and hydrochloric acid as a model reaction is proposed. In the introductory part of the exercise, the induction period and subsequent thermal runaway behavior are evaluated via a simple observation of hydrogen gas evolution and…

  4. The oxygen evolution reaction on cobalt Part I. Reaction order experiments and impedance measurements

    NARCIS (Netherlands)

    Kobussen, A.G.C.; Willems, H.; Wit, J.H.W. de; Broers, G.H.J.

    1984-01-01

    It was found that the oxygen evolution reaction on cobalt in concentrated KOH solutions can be described differently for low and high overpotentials. In the overpotential range from 150 to 280 mV, the reaction has a Tafel slope of approximately 40 mV and a reaction order with respect to the KOH

  5. Synthesis and Reactions of Acenaphthenequinones-Part-2. The Reactions of Acenaphthenequinones

    Directory of Open Access Journals (Sweden)

    Mahmoud Shoukry

    2002-02-01

    Full Text Available The reactions of acenaphthenequinone and its derivatives with different nucleophiles, organic and inorganic reagents are reviewed. This survey also covers their oxidation and reduction reactions, in addition to many known reactions such as Friedel Crafts, Diels-Alder, bromination and thiolation.

  6. A Green Multicomponent Reaction for the Organic Chemistry Laboratory: The Aqueous Passerini Reaction

    Science.gov (United States)

    Hooper, Matthew M.; DeBoef, Brenton

    2009-01-01

    Water is the ideal green solvent for organic reactions. However, most organic molecules are insoluble in it. Herein, we report a laboratory module that takes advantage of this property. The Passerini reaction, a three-component coupling involving an isocyanide, aldehyde, and carboxylic acid, typically requires [similar to] 24 h reaction times in…

  7. High-precision (p,t) reactions to determine reaction rates of explosive stellar processes

    NARCIS (Netherlands)

    Matić, Andrija

    2007-01-01

    The aim of my study was to investigate the nuclear structure of 22Mg and 26Si. These two nuclei play a significant role in stellar reaction processes at high temperatures. On base of the obtained nuclear structure we calculated the stellar reaction rates for the following reactions: 18Ne(α,p)21Na,

  8. Trend to equilibrium for a reaction-diffusion system modelling reversible enzyme reaction

    OpenAIRE

    Elias, Jan

    2016-01-01

    20 pages; A spatio-temporal evolution of chemicals appearing in a reversible enzyme reaction and modelled by a four component reaction-diffusion system with the reaction terms obtained by the law of mass action is considered. The large time behaviour of the system is studied by means of entropy methods.

  9. Trend to Equilibrium for a Reaction-Diffusion System Modelling Reversible Enzyme Reaction.

    Science.gov (United States)

    Eliaš, Ján

    2018-01-01

    A spatio-temporal evolution of chemicals appearing in a reversible enzyme reaction and modelled by a four-component reaction-diffusion system with the reaction terms obtained by the law of mass action is considered. The large time behaviour of the system is studied by means of entropy methods.

  10. Severe catastrophes and public reactions

    International Nuclear Information System (INIS)

    Osmachkin, Vitaly

    2002-01-01

    nuclear opposition. Economical basis of nuclear energy stagnation is in not very successful competition of nuclear engineering with fossil energy production technologies. Much money has been spent for improvement of safety of NPPs. Social roots of the opposition are linked with a bad experience of the public with demonstration of the nuclear energy- The explosion of atomic bombs, some contamination of the territories after nuclear arm tests, misfortunes with TMI-2 and Chernobyl have created a stable enmity and non-acceptance of the all connected with 'atom'. The mass media have strongly promoted the dissemination of the fear of radiation exposures. There is also an influence on that attitude the radiation protection regulation via the declaration of the linear no-threshold dependence of the radiation detriments and dose of exposure. Such concept ignores the adoptive features of all living. But modem studies have showed that protracted irradiation at the same dose is much less dangerous compared with sharp one. It could change public attitude to nuclear energy in the society. Role of nuclear communication for public informing: The reactions of public on various technological and man-made events differ significantly and are being determined not scales of catastrophes but the mental impression and a multiplication of psychological stresses in the society by mass -media. In present situation a nuclear community has to improve the contacts with the pubic, to launch more effective campaign for explanation of real adventures of nuclear power. It needs to compare the risks of climate warming and health detriments from different electricity production technologies and to show that nuclear power is a single alternative all fossil burning techniques of electricity production. It's the truth the nuclear power is a real method of fight for suppression of emission the greenhouse gases, isn't it? (author)

  11. Department of Nuclear Reactions - Overview

    International Nuclear Information System (INIS)

    Rusek, K.

    2008-01-01

    . Jaskola joined a collaboration of many Polish institutions and performed a series of experiments at the Heavy Ion Laboratory of Warsaw University devoted to a study of cell survival after irradiation by ions from the Warsaw Cyclotron. Finally, I would like to warmly welcome drs H.P. Morsch and N. Keeley who joined us last year. Dr Morsch is collaborating with Assoc. Prof. P. Zupranski on a multi-gluon field approach within Quantum Chromodynamics. Dr Keeley's interest is in low energy nuclear reactions. I would also like to welcome our new PhD students, Ms I. Strojek, Mr l. Standylo and Mr Shaaban Abd El Aal. With Mr Abd El Aal we are opening a new field of applications of nuclear methods, studying ancient Egyptian frescos by means of proton induced X-ray emission (PIXE). As every year, apart from purely scientific activities, a few of our colleagues have been involved in education, giving lectures to students from highs Schools in Warsaw and to students of Warsaw University. (author)

  12. Department of Nuclear Reactions: Overview

    International Nuclear Information System (INIS)

    Rusek, K.

    2005-01-01

    Full text: It is surprising how so few under-paid scientists could do so much. During 2004 the number of papers published or being in press exceeded fifty, making almost three papers per person employed in our department. Furthermore, among these papers one was published in Nature, the World's highest-ranked scientific journal. This is a result that will be difficult to beat. It is my pleasure to mention that one of our PhD students, Mr Sergiy Mezhevych, won a prestigious Heavy Ion Laboratory Prize founded by Prof. Inamura, for his experimental work using a beam from the Warsaw Cyclotron. Thanks to the effort of our colleagues the Hermes Collaboration Meeting organized by IPJ in Kazimierz Dolny (June 25 - July 1) turned out a success. The following short reports cover the three major domains of our scientific activities: nuclear, materials and atomic physics. -Nuclear physics - The structure of light nuclei, including exotic radioactive isotopes, was investigated both experimentally and theoretically. Some experimental studies were performed at the Heavy Ion Laboratory of Warsaw University in collaboration with scientists from the Institute of Nuclear Research in Kiev, Ukraine. The two reports present interesting results for the rare carbon isotope, 14 C. In the framework of Feshbach, Kerman and Koonin theory the multistep emission of one particle as well as more complicated direct processes were studied. It was found that these more complex processes play an important role in proton induced reactions. Experimental data from projectile-multifragmentation experiments with stable and radioactive beams were analysed. Some preliminary results are presented. Using a proton beam provided by the C-30 compact cyclotron at Swierk, detectors consisting of a PWO scintillator coupled to avalanche photodiodes were tested. The aim of these tests was to find the best detectors for the large electromagnetic calorimeter which will be used in future PANDA Collaboration experiments

  13. Resonant elastic scattering, inelastic scattering and astrophysical reactions; Diffusion elastique resonante, diffusion inelastique et reactions astrophysiques

    Energy Technology Data Exchange (ETDEWEB)

    De Oliveira Santos, F. [Grand Accelerateur National d' Ions Lourds, UMR 6415, 14 - Caen (France)

    2007-07-01

    Nuclear reactions can occur at low kinetic energy. Low-energy reactions are characterized by a strong dependence on the structure of the compound nucleus. It turns out that it is possible to study the nuclear structure by measuring these reactions. In this course, three types of reactions are treated: Resonant Elastic Scattering (such as N{sup 14}(p,p)N{sup 14}), Inelastic Scattering (such as N{sup 14}(p,p')N{sup 14*}) and Astrophysical reactions (such as N{sup 14}(p,{gamma})O{sup 15}). (author)

  14. Kiss-induced severe anaphylactic reactions

    Directory of Open Access Journals (Sweden)

    Atanasković-Marković Marina

    2010-01-01

    Full Text Available Introduction. Ingestion is the principal route for food allergens to trigger allergic reaction in atopic persons. However, in some highly sensitive patients severe symptoms may develop upon skin contact and by inhalation. The clinical spectrum ranges from mild facial urticaria and angioedema to life-threatening anaphylactic reactions. Outline of Cases. We describe cases of severe anaphylactic reactions by skin contact, induced by kissing in five children with prior history of severe anaphylaxis caused by food ingestion. These cases were found to have the medical history of IgE mediated food allergy, a very high total and specific serum IgE level and very strong family history of allergy. Conclusion. The presence of tiny particles of food on the kisser's lips was sufficient to trigger an anaphylactic reaction in sensitized children with prior history of severe allergic reaction caused by ingestion of food. Allergic reaction provoked with food allergens by skin contact can be a risk factor for generalized reactions. Therefore, extreme care has to be taken in avoiding kissing allergic children after eating foods to which they are highly allergic. Considering that kissing can be a cause of severe danger for the food allergic patient, such persons should inform their partners about the risk factor for causing their food hypersensitivity.

  15. Spontaneous Hedonic Reactions to Social Media Cues.

    Science.gov (United States)

    van Koningsbruggen, Guido M; Hartmann, Tilo; Eden, Allison; Veling, Harm

    2017-05-01

    Why is it so difficult to resist the desire to use social media? One possibility is that frequent social media users possess strong and spontaneous hedonic reactions to social media cues, which, in turn, makes it difficult to resist social media temptations. In two studies (total N = 200), we investigated less-frequent and frequent social media users' spontaneous hedonic reactions to social media cues using the Affect Misattribution Procedure-an implicit measure of affective reactions. Results demonstrated that frequent social media users showed more favorable affective reactions in response to social media (vs. control) cues, whereas less-frequent social media users' affective reactions did not differ between social media and control cues (Studies 1 and 2). Moreover, the spontaneous hedonic reactions to social media (vs. control) cues were related to self-reported cravings to use social media and partially accounted for the link between social media use and social media cravings (Study 2). These findings suggest that frequent social media users' spontaneous hedonic reactions in response to social media cues might contribute to their difficulties in resisting desires to use social media.

  16. Prevention of allergic reactions in anesthetized patients.

    Science.gov (United States)

    Caffarelli, C; Stringari, G; Miraglia Del Giudice, M; Crisafulli, G; Cardinale, F; Peroni, D G; Bernardini, R

    2011-01-01

    Hypersensitivity reactions during perioperative period are increasing and may be potentially life-threatening. Therefore, major emphasis is given to prevention. We perform a review to examine which measures should be taken to prevent reactions to products used in elective and emergency surgery. Any patient with a history of previous anaphylaxis or severe reaction during anaesthesia should be referred to allergist for detection of the offending compound. However, the identification of the triggering agent is not always feasible because of the low accuracy of diagnostic tests. In these cases and when emergency surgery is required, it should be considered to replace all drugs administered before the onset of the reaction with alternatives. Furthermore, any cross-reacting agent and latex, especially in patients belonging to populations at-risk for latex allergy should be avoided. In susceptible patients, premedication with antihistamines and corticosteroids might reduce the severity of reaction to drugs or contrast material while it is unclear whether pre-treatment decreases incidence of anaphylactic reactions. There is no evidence that premedication prevents allergic reactions to latex. Overall, physicians should not rely on the efficacy of premedication.

  17. Photogeochemical reactions of manganese under anoxic conditions

    Science.gov (United States)

    Liu, W.; Yee, N.; Piotrowiak, P.; Falkowski, P. G.

    2017-12-01

    Photogeochemistry describes reactions involving light and naturally occurring chemical species. These reactions often involve a photo-induced electron transfer that does not occur in the absence of light. Although photogeochemical reactions have been known for decades, they are often ignored in geochemical models. In particular, reactions caused by UV radiation during an ozone free early Earth could have influenced the available oxidation states of manganese. Manganese is one of the most abundant transition metals in the crust and is important in both biology and geology. For example, the presence of manganese (VI) oxides in the geologic record has been used as a proxy for oxygenic photosynthesis; however, we suggest that the high oxidation state of Mn can be produced abiotically by photochemical reactions. Aqueous solutions of manganese (II) as well as suspensions of rhodochrosite (MnCO3) were irradiated under anoxic condition using a 450 W mercury lamp and custom built quartz reaction vessels. The photoreaction of the homogeneous solution of Mn(II) produced H2 gas and akhtenskite (ɛ-MnO2) as the solid product . This product is different than the previously identified birnessite. The irradiation of rhodochrosite suspensions also produced H2 gas and resulted in both a spectral shift as well as morphology changes of the mineral particles in the SEM images. These reactions offer alternative, abiotic pathways for the formation of manganese oxides.

  18. ReactionMap: an efficient atom-mapping algorithm for chemical reactions.

    Science.gov (United States)

    Fooshee, David; Andronico, Alessio; Baldi, Pierre

    2013-11-25

    Large databases of chemical reactions provide new data-mining opportunities and challenges. Key challenges result from the imperfect quality of the data and the fact that many of these reactions are not properly balanced or atom-mapped. Here, we describe ReactionMap, an efficient atom-mapping algorithm. Our approach uses a combination of maximum common chemical subgraph search and minimization of an assignment cost function derived empirically from training data. We use a set of over 259,000 balanced atom-mapped reactions from the SPRESI commercial database to train the system, and we validate it on random sets of 1000 and 17,996 reactions sampled from this pool. These large test sets represent a broad range of chemical reaction types, and ReactionMap correctly maps about 99% of the atoms and about 96% of the reactions, with a mean time per mapping of 2 s. Most correctly mapped reactions are mapped with high confidence. Mapping accuracy compares favorably with ChemAxon's AutoMapper, versions 5 and 6.1, and the DREAM Web tool. These approaches correctly map 60.7%, 86.5%, and 90.3% of the reactions, respectively, on the same data set. A ReactionMap server is available on the ChemDB Web portal at http://cdb.ics.uci.edu .

  19. Local and general anesthetics immediate hypersensitivity reactions.

    Science.gov (United States)

    Volcheck, Gerald W; Mertes, Paul Michel

    2014-08-01

    Intraoperative anaphylaxis and hypersensitivity reactions in the setting of anesthesia contribute significantly to the morbidity and mortality of surgeries and surgical procedures. Because multiple medications and products are given in a short period of time, identifying the specific cause can be difficult. Neuromuscular blocking agents, antibiotics, and latex are the most common causes of anesthesia-related reactions, though other medications or exposures could be involved. Careful review of anesthetic charts and allergy testing can help identify the underlying cause. The identification of the cause and subsequent prevention of reactions are critical to reduce overall mortality and morbidity related to anesthesia. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Polar reactions of acyclic conjugated bisallenes

    Directory of Open Access Journals (Sweden)

    Reiner Stamm

    2013-01-01

    Full Text Available The chemical behaviour of various alkyl-substituted, acyclic conjugated bisallenes in reactions involving polar intermediates and/or transition states has been investigated on a broad scale for the first time. The reactions studied include lithiation, reaction of the thus formed organolithium salts with various electrophiles (among others, allyl bromide, DMF and acetone, oxidation to cyclopentenones and epoxides, hydrohalogenation (HCl, HBr addition, halogenation (Br2 and I2 addition, and [2 + 2] cycloaddition with chlorosulfonyl isocyanate. The resulting adducts were fully characterized by spectroscopic and analytical methods; they constitute interesting substrates for further organic transformations.

  1. Rates of Thermonuclear Reactions in Dense Plasmas

    International Nuclear Information System (INIS)

    Tsytovich, V.N.; Bornatici, M.

    2000-01-01

    The problem of plasma screening of thermonuclear reactions has attracted considerable scientific interest ever since Salpeter's seminal paper, but it is still faced with controversial statements and without any definite conclusion. It is of relevant importance to thermonuclear reactions in dense astrophysical plasmas, for which charge screening can substantially affect the reaction rates. Whereas Salpeter and a number of subsequent investigations have dealt with static screening, Carraro, Schafer, and Koonin have drawn attention to the fact that plasma screening of thermonuclear reactions is an essentially dynamic effect. In addressing the issue of collective plasma effects on the thermonuclear reaction rates, the first critical overview of most of the work carried out so far is presented and the validity of the test particle approach is assessed. In contrast to previous investigations, we base our description on the kinetic equation for nonequilibrium plasmas, which accounts for the effects on the rates of thermonuclear reactions of both plasma fluctuations and screening and allows one to analyze explicitly the effects of the fluctuations on the reaction rates. Such a kinetic formulation is more general than both Salpeter's approach and the recently developed statistical approaches and makes it possible to obtain a more comprehensive understanding of the problem. A noticeable result of the fluctuation approach is that the static screening, which affects both the interaction and the self-energy of the reacting nuclei, does not affect the reaction rates, in contrast with the results obtained so far. Instead, a reduction of the thermonuclear reaction rates is obtained as a result of the effect of plasma fluctuations related to the free self-energy of the reacting nuclei. A simple physical explanation of the slowing down of the reaction rates is given, and the relation to the dynamically screened test particle approach is discussed. Corrections to the reaction rates

  2. Flows and chemical reactions in heterogeneous mixtures

    CERN Document Server

    Prud'homme, Roger

    2014-01-01

    This book - a sequel of previous publications 'Flows and Chemical Reactions' and 'Chemical Reactions in Flows and Homogeneous Mixtures' - is devoted to flows with chemical reactions in heterogeneous environments.  Heterogeneous media in this volume include interfaces and lines. They may be the site of radiation. Each type of flow is the subject of a chapter in this volume. We consider first, in Chapter 1, the question of the generation of environments biphasic individuals: dusty gas, mist, bubble flow.  Chapter 2 is devoted to the study at the mesoscopic scale: particle-fluid exchange of mom

  3. Lithium induced nuclear reactions of astrophysical interest

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.P. [CIAE, China Institute of Atomic Energy, P. O. Box 275(1), Beijing 102413 (China); Li, Z.H.; Bai, X.X.; Wang, Y.B.; Lian, G.; Guo, B.; Su, J.; Zeng, S.; Wang, B.X.; Yan, S.Q.; Li, Y.J.; Li, E.T. [CIAE, China Institute of Atomic Energy, P. O. Box 275(46), Beijing 102413 (China)

    2010-03-01

    Systematic studies of nuclear astrophysical reactions induced by lithium isotopes using the unstable ion beam facility GIRAFFE in CIAE were performed. We have measured the angular distributions of some single nucleon transfer reactions, such as {sup 8}Li(d,p){sup 9}Li, {sup 8}Li(d,n){sup 9}Be and {sup 8}Li(p,d){sup 7}Li in inverse kinematics, and derived the astrophysical S-factors or reaction rates for {sup 8}Li(n,gamma){sup 9}Li and {sup 8}Li(p,gamma){sup 9}Be by using asymptotic normalization coefficient (ANC) or spectroscopic factor.

  4. Nuclear reaction inputs based on effective interactions

    Energy Technology Data Exchange (ETDEWEB)

    Hilaire, S.; Peru, S.; Dubray, N.; Dupuis, M.; Bauge, E. [CEA, DAM, DIF, Arpajon (France); Goriely, S. [Universite Libre de Bruxelles, Institut d' Astronomie et d' Astrophysique, CP-226, Brussels (Belgium)

    2016-11-15

    Extensive nuclear structure studies have been performed for decades using effective interactions as sole input. They have shown a remarkable ability to describe rather accurately many types of nuclear properties. In the early 2000 s, a major effort has been engaged to produce nuclear reaction input data out of the Gogny interaction, in order to challenge its quality also with respect to nuclear reaction observables. The status of this project, well advanced today thanks to the use of modern computers as well as modern nuclear reaction codes, is reviewed and future developments are discussed. (orig.)

  5. Supercritical Fluid Reactions for Coal Processing

    Energy Technology Data Exchange (ETDEWEB)

    Charles A. Eckert

    1997-11-01

    Exciting opportunities exist for the application of supercritical fluid (SCF) reactions for the pre-treatment of coal. Utilizing reactants which resemble the organic nitrogen containing components of coal, we developed a method to tailor chemical reactions in supercritical fluid solvents for the specific application of coal denitrogenation. The tautomeric equilibrium of a Schiff base was chosen as one model system and was investigated in supercritical ethane and cosolvent modified supercritical ethane. The Diels-Alder reaction of anthracene and 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) was selected as a second model system, and it was investigated in supercritical carbon dioxide.

  6. Morphing of the Dissipative Reaction Mechanism

    International Nuclear Information System (INIS)

    Schroeder, W.U.; Toke, J.; Gawlikowicz, W.; Houck, M.A.; Lu, J.; Pienkowski, L.

    2003-01-01

    Important trends in the evolution of heavy-ion reaction mechanisms with bombarding energy and impact parameter are reviewed. Essential features of dissipative reactions appear preserved at E/A = 50-62 MeV, such as dissipative orbiting and multi-nucleon exchange. The relaxation of the A/Z asymmetry with impact parameter is slow. Non-equilibrium emission of light particles and clusters is an important process accompanying the evolution of the mechanism. Evidence is presented for a new mechanism of statistical cluster emission from hot, metastable primary reaction products, driven by surface entropy. These results suggest a plausible reinterpretation of multi-fragmentation. (authors)

  7. Conservation Laws in Biochemical Reaction Networks

    DEFF Research Database (Denmark)

    Mahdi, Adam; Ferragut, Antoni; Valls, Claudia

    2017-01-01

    We study the existence of linear and nonlinear conservation laws in biochemical reaction networks with mass-action kinetics. It is straightforward to compute the linear conservation laws as they are related to the left null-space of the stoichiometry matrix. The nonlinear conservation laws...... are difficult to identify and have rarely been considered in the context of mass-action reaction networks. Here, using the Darboux theory of integrability, we provide necessary structural (i.e., parameterindependent) conditions on a reaction network to guarantee the existence of nonlinear conservation laws...

  8. Reactions of nitrogen oxides with polymers

    Energy Technology Data Exchange (ETDEWEB)

    Pariiskii, Georgii B; Gaponova, I S; Davydov, Evgenii Ya [N.M. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow (Russian Federation)

    2000-11-30

    The mechanisms of the reactions of nitrogen oxides and different classes of solid polymers are considered. Particular emphasis is given to the analysis of the mechanisms of the formation of stable nitroxyl radicals. Double bonds and amide groups of macromolecules, as well as hydroperoxides and peroxide macroradicals are shown to be involved in the reactions with nitrogen oxides. The application of nitrogen oxides for the preparation of spin-labelled polymers and the use of the ESR imaging technique (ESR tomography) for the investigation of the structure of the reaction front during nitration of solid polymers are considered. The bibliography includes 111 references.

  9. Nuclear chain reaction: forty years later

    International Nuclear Information System (INIS)

    Sachs, R.G.

    1984-01-01

    The proceedings from a 1982 symposium 40 years after the first controlled nuclear chain reaction took place in Chicago covers four sessions and public discussion. The session covered the history of the chain reaction; peaceful uses in technology, medicine, and biological science; peaceful uses in power generation; and nuclear weapons control. Among the speakers were Eugene Wigner, Glenn Seaborg, Alvin Weinberg, and others who participated in the first chain reaction experiments. The proceedings reflect differences of opinion among the scientists as well as the general public. References, slides, and tables used to illustrate the individual talks are included with the papers

  10. Radiative capture reactions via indirect methods

    Science.gov (United States)

    Mukhamedzhanov, A. M.; Rogachev, G. V.

    2017-10-01

    Many radiative capture reactions of astrophysical interest occur at such low energies that their direct measurement is hardly possible. Until now the only indirect method, which was used to determine the astrophysical factor of the astrophysical radiative capture process, was the Coulomb dissociation. In this paper we address another indirect method, which can provide information about resonant radiative capture reactions at astrophysically relevant energies. This method can be considered an extension of the Trojan horse method for resonant radiative capture reactions. The idea of the suggested indirect method is to use the indirect reaction A (a ,s γ )F to obtain information about the radiative capture reaction A (x ,γ )F , where a =(s x ) and F =(x A ) . The main advantage of using the indirect reactions is the absence of the penetrability factor in the channel x +A , which suppresses the low-energy cross sections of the A (x ,γ )F reactions and does not allow one to measure these reactions at astrophysical energies. A general formalism to treat indirect resonant radiative capture reactions is developed when only a few intermediate states contribute and a statistical approach cannot be applied. The indirect method requires coincidence measurements of the triple differential cross section, which is a function of the photon scattering angle, energy, and the scattering angle of the outgoing spectator particle s . Angular dependence of the triple differential cross section at fixed scattering angle of the spectator s is the angular γ -s correlation function. Using indirect resonant radiative capture reactions, one can obtain information about important astrophysical resonant radiative capture reactions such as (p ,γ ) , (α ,γ ) , and (n ,γ ) on stable and unstable isotopes. The indirect technique makes accessible low-lying resonances, which are close to the threshold, and even subthreshold bound states located at negative energies. In this paper, after

  11. Tryptase in diagnosing adverse suspected anaphylactic reaction.

    Science.gov (United States)

    Michalska-Krzanowska, Grazyna

    2012-01-01

    Determination of serum mast cell tryptase (MCT) is becoming more widely used in diagnosing allergic reactions involving mast cells. It can help evaluate the allergenic effects of drugs administered during anesthesia and the perioperative period. Until now, data about the role of tryptase in the body has not been clarified yet. Patients with elevated MCT levels should undergo further testing to find out the causative agent of a potential allergic reaction. Patients with normal tryptase concentration should also undergo further diagnosis if they manifest clinical symptoms of a severe anaphylactic reaction.

  12. Photochemical Hexadehydro-Diels-Alder Reaction.

    Science.gov (United States)

    Xu, Feng; Xiao, Xiao; Hoye, Thomas R

    2017-06-28

    We demonstrate that the hexadehydro-Diels-Alder (HDDA) cycloisomerization reaction to produce reactive benzyne derivatives can be initiated photochemically. As with the thermal variant of the HDDA process, the reactive intermediates are formed in the absence of reagents or the resulting byproducts required for the generation of benzynes by traditional methods. This photo-HDDA (or hν-HDDA) reaction occurs at much lower temperatures (including even at -70 °C) than the thermal HDDA, but the benzynes produced behave in the same fashion with respect to their trapping reactions, suggesting they are of the same electronic state.

  13. Thermonuclear reaction rates for proton induced reactions on 41K and neutron induced reactions on 41Ca

    International Nuclear Information System (INIS)

    Sevior, M.E.; Anderson, M.R.; Mitchell, L.W.; Kennett, S.R.; Sargood, D.G.

    1981-01-01

    The yield of γ-rays from the reaction 41 K(p,γ) 42 Ca has been measured as a function of bombarding energy over the range 0.68-2.48 MeV and from the reaction 41 K(p,αγ) 38 Ar over the range 1.20-2.48 MeV, and the yield of neutrons from the reaction 41 K(p,n) 41 Ca has been measured from threshold to a bombarding energy of 2.48 MeV. The energy dependence of the cross sections is compared with statistical-model calculations with global optical model parameters in all particle channels. The calculations seriously overestimate the cross section for the neutron channel and underestimate those for the other channels. A reduction in the imaginary well depth in the neutron channel leads to good agreement with all the data. Statistical-model calculations with this modified set of parameters are then carried out to provide cross sections for the astrophysically interesting reactions 41 Ca(n,p) 41 K, 41 Ca(n,α) 38 Ar, and 41 Ca(n,γ) 42 Ca. Thermonuclear reaction rates are calculated for all six reactions over the temperature range 5 x 10 8 - 10 1 0K which includes the range of temperatures of interest in nucleosynthesis calculations

  14. Kinetics interpretation model of isothermal martensite reactions

    International Nuclear Information System (INIS)

    Guimaraes, J.R.C.

    1976-01-01

    It was discussed details associated to the interpretation of kinetics of martencite heterogeneous nucleation in isothermal reactions. It was proposed a model which allows compute the variation of concentration of preferencial sites nucleation with a volumetric martencite fraction [pt

  15. Injection site reactions after subcutaneous oligonucleotide therapy

    NARCIS (Netherlands)

    van Meer, L. (Leonie); M. Moerland (Matthijs); Gallagher, J. (Jolie); M.B.A. van Doorn (Martijn); E.P. Prens (Errol); A.F. Cohen; Rissmann, R. (Robert); J. Burggraaf (Jacobus)

    2016-01-01

    textabstractOligonucleotides (ONs) are short fragments of nucleic acids, currently being investigated as therapeutic agents. When administered subcutaneously (sc), ONs cause a specific local reaction originating around the injection site, such as erythema, itching, discomfort and pain, including

  16. Polymerase chain reaction identification of Trypanosoma brucei ...

    African Journals Online (AJOL)

    Polymerase chain reaction identification of Trypanosoma brucei rhodesiense in wild tsetse flies from Nkhotakota Wildlife Reserve, Malawi. Janelisa Musaya, John Chisi, Edward Senga, Peter Nambala, Emmanuel Maganga, Enock Matovu, John Enyaru ...

  17. Chemical Reactions at Surfaces. Final Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Freud, Hans-Joachim [Max-Planck-Gesellschaft, Berlin (Germany). Fritz-Haber-Inst.

    2003-02-21

    The Gordon Research Conference (GRC) on Chemical Reactions at Surfaces was held at Holiday Inn, Ventura, California, 2/16-21/03. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  18. Adverse drug reactions: classification, susceptibility and reporting.

    Science.gov (United States)

    Kaufman, Gerri

    2016-08-10

    Adverse drug reactions (ADRs) are increasingly common and are a significant cause of morbidity and mortality. Historically, ADRs have been classified as type A or type B. Type A reactions are predictable from the known pharmacology of a drug and are associated with high morbidity and low mortality. Type B reactions are idiosyncratic, bizarre or novel responses that cannot be predicted from the known pharmacology of a drug and are associated with low morbidity and high mortality. Not all ADRs fit into type A and type B categories; therefore, additional categories have been developed. These include type C (continuing), type D (delayed use), and type E (end of use) reactions. Susceptibility to ADRs is influenced by age, gender, disease states, pregnancy, ethnicity and polypharmacy. Drug safety is reliant on nurses and other healthcare professionals being alert to the possibility of ADRs, working with patients to optimise medicine use and exercising vigilance in the reporting of ADRs through the Yellow Card Scheme.

  19. Multistage reaction pathways in detonating high explosives

    International Nuclear Information System (INIS)

    Li, Ying; Kalia, Rajiv K.; Nakano, Aiichiro; Nomura, Ken-ichi; Vashishta, Priya

    2014-01-01

    Atomistic mechanisms underlying the reaction time and intermediate reaction products of detonating high explosives far from equilibrium have been elusive. This is because detonation is one of the hardest multiscale physics problems, in which diverse length and time scales play important roles. Here, large spatiotemporal-scale reactive molecular dynamics simulations validated by quantum molecular dynamics simulations reveal a two-stage reaction mechanism during the detonation of cyclotrimethylenetrinitramine crystal. Rapid production of N 2 and H 2 O within ∼10 ps is followed by delayed production of CO molecules beyond ns. We found that further decomposition towards the final products is inhibited by the formation of large metastable carbon- and oxygen-rich clusters with fractal geometry. In addition, we found distinct unimolecular and intermolecular reaction pathways, respectively, for the rapid N 2 and H 2 O productions

  20. An Elegant Example of Chemoselective Reaction

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 10. An Elegant Example of a Chemoselective Reaction - The Preparation of Sulfonamide Drugs. Gopalpur Nagendrappa. General Article Volume 13 Issue 10 October ... Keywords. Chemoselectivity; sulfa drugs; sulfonamides; amide hydrolysis.