Estimation of (n,f) Cross-Sections by Measuring Reaction Probability Ratios

Energy Technology Data Exchange (ETDEWEB)

Plettner, C; Ai, H; Beausang, C W; Bernstein, L A; Ahle, L; Amro, H; Babilon, M; Burke, J T; Caggiano, J A; Casten, R F; Church, J A; Cooper, J R; Crider, B; Gurdal, G; Heinz, A; McCutchan, E A; Moody, K; Punyon, J A; Qian, J; Ressler, J J; Schiller, A; Williams, E; Younes, W

2005-04-21

Neutron-induced reaction cross-sections on unstable nuclei are inherently difficult to measure due to target activity and the low intensity of neutron beams. In an alternative approach, named the 'surrogate' technique, one measures the decay probability of the same compound nucleus produced using a stable beam on a stable target to estimate the neutron-induced reaction cross-section. As an extension of the surrogate method, in this paper they introduce a new technique of measuring the fission probabilities of two different compound nuclei as a ratio, which has the advantage of removing most of the systematic uncertainties. This method was benchmarked in this report by measuring the probability of deuteron-induced fission events in coincidence with protons, and forming the ratio P({sup 236}U(d,pf))/P({sup 238}U(d,pf)), which serves as a surrogate for the known cross-section ratio of {sup 236}U(n,f)/{sup 238}U(n,f). IN addition, the P({sup 238}U(d,d{prime}f))/P({sup 236}U(d,d{prime}f)) ratio as a surrogate for the {sup 237}U(n,f)/{sup 235}U(n,f) cross-section ratio was measured for the first time in an unprecedented range of excitation energies.

Elementary Steps of Syngas Reactions on Mo2C(001): Adsorption Thermochemistry and Bond Dissociation

Energy Technology Data Exchange (ETDEWEB)

Medford, Andrew

2012-02-16

Density functional theory (DFT) and ab initio thermodynamics are applied in order to investigate the most stable surface and subsurface terminations of Mo{sub 2}C(001) as a function of chemical potential and in the presence of syngas. The Mo-terminated (001) surface is then used as a model surface to evaluate the thermochemistry and energetic barriers for key elementary steps in syngas reactions. Adsorption energy scaling relations and Broensted-Evans-Polanyi relationships are established and used to place Mo{sub 2}C into the context of transition metal surfaces. The results indicate that the surface termination is a complex function of reaction conditions and kinetics. It is predicted that the surface will be covered by either C{sub 2}H{sub 2} or O depending on conditions. Comparisons to transition metals indicate that the Mo-terminated Mo{sub 2}C(001) surface exhibits carbon reactivity similar to transition metals such as Ru and Ir, but is significantly more reactive towards oxygen.

HTP kinetics studies on isolated elementary combustion reactions over wide temperature ranges

Energy Technology Data Exchange (ETDEWEB)

Fontijn, A.; Adusei, G.Y.; Hranisavlevic, J.; Bajaj, P.N. [Rensselaer Polytechnic Institute, Troy, NY (United States)

1993-12-01

The goals of this project are to provide accurate data on the temperature dependence of the kinetics of elementary combustion reactions, (i) for use by combustion modelers, and (ii) to gain a better fundamental understanding of, and hence predictive ability for, the chemistry involved. Experimental measurements are made mainly by using the pseudo-static HTP (high-temperature photochemistry) technique. While continuing rate coefficient measurements, further aspects of kinetics research are being explored. Thus, starting from the data obtained, a method for predicting the temperature dependence of rate coefficients of oxygen-atom olefin experiment and confirms the underlying mechanistic assumptions. Mechanistic information of another sort, i.e. by product analysis, has recently become accessible with the inauguration of our heated flow tube mass spectrometer facility; early results are reported here. HTP experiments designed to lead to measurements of product channels by resonance fluorescence have started.

Excitation function and isomeric ratio of Tc-isotopes from the 93Nb(α, xn) reaction

International Nuclear Information System (INIS)

Kim, K.; Kim, G.N.; Naik, H.; Zaman, M.; Yang, S.-C.; Song, T.-Y.; Guin, R.; Das, S.K.

2015-01-01

The excitation functions of 94–96 Tc isotopes and independent isomeric ratios of 93m, g Tc, 94m, g Tc, and 95m, g Tc from the 93 Nb(α, xn) reaction within the energy range below 40 MeV have been determined by using a stacked-foil activation and an off-line γ-ray spectrometric technique at the Variable Energy Cyclotron Center, Kolkota, India. The excitation function of 94–96 Tc in the 93 Nb(α, xn) reaction was also calculated by using the computer code TALYS 1.6. The present data are found to be in general agreement with the literature data but have similar trend with some deviation from calculated data of the TALYS 1.6 code. The isomeric ratios of 93m, g Tc, 94m, g Tc, and 95m, g Tc in the 93 Nb(α, xn) reactions from the present work and literature data were compared with similar data in the 93 Nb( 3 He, xn) and 96 Mo(p, xn) reactions. In all the three reactions, the isomeric ratios increase with the increasing excitation energy. However, at all excitation energies, the isomeric ratios of 93m, g Tc, 94m, g Tc, and 95m, g Tc in the 93 Nb(α, xn) and 93 Nb( 3 He, xn) reactions are higher than those in the 96 Mo(p, xn) reactions, which indicate the role of input angular momentum besides excitation energy. Above the excitation energy of 35–55 MeV, the isomeric ratios of 95m, g Tc, 94m, g Tc, and 93m, g Tc decrease in all the 93 Nb(α, xn), 93 Nb( 3 He, xn) and 96 Mo(p, xn) reactions. This decreasing trend at higher excitation energy indicates the starting of pre-equilibrium reaction, which depends on the target, projectile, and type of reaction products

Single-molecule detection of dihydroazulene photo-thermal reaction using break junction technique

Science.gov (United States)

Huang, Cancan; Jevric, Martyn; Borges, Anders; Olsen, Stine T.; Hamill, Joseph M.; Zheng, Jue-Ting; Yang, Yang; Rudnev, Alexander; Baghernejad, Masoud; Broekmann, Peter; Petersen, Anne Ugleholdt; Wandlowski, Thomas; Mikkelsen, Kurt V.; Solomon, Gemma C.; Brøndsted Nielsen, Mogens; Hong, Wenjing

2017-05-01

Charge transport by tunnelling is one of the most ubiquitous elementary processes in nature. Small structural changes in a molecular junction can lead to significant difference in the single-molecule electronic properties, offering a tremendous opportunity to examine a reaction on the single-molecule scale by monitoring the conductance changes. Here, we explore the potential of the single-molecule break junction technique in the detection of photo-thermal reaction processes of a photochromic dihydroazulene/vinylheptafulvene system. Statistical analysis of the break junction experiments provides a quantitative approach for probing the reaction kinetics and reversibility, including the occurrence of isomerization during the reaction. The product ratios observed when switching the system in the junction does not follow those observed in solution studies (both experiment and theory), suggesting that the junction environment was perturbing the process significantly. This study opens the possibility of using nano-structured environments like molecular junctions to tailor product ratios in chemical reactions.

Radioactive nuclide production and isomeric state branching ratios in P + W reactions to 200 mev

International Nuclear Information System (INIS)

Young, P.G.; Chadwick, M.B.

1995-01-01

Calculations of nuclide yields from spallation reactions usually assume that the products are formed in their ground states. We are performing calculations of product yields from proton reactions on tungsten isotopes that explicitly account for formation of the residual nuclei in excited states. The Hauser-Feshbach statistical/preequilibrium code GNASH, with full accounting for angular momentum conservation and electromagnetic transitions, is utilized in the calculations. We present preliminary results for isomer branching ratios for proton reactions to 200 MeV for several products including the 31-y, 16+ state in l78 Hf and the 25-d, 25/2- state in 179 Hf. Knowledge of such branching ratios, might be important for concepts such as accelerator production of tritium that utilize intermediate-energy proton reactions on tungsten

Weathering reactions and isometric log-ratio coordinates: Do they speak to each other?

International Nuclear Information System (INIS)

Buccianti, Antonella; Zuo, Renguang

2016-01-01

The aim of this contribution is to explore the relationship among some concepts, often considered to be unrelated, such as weathering reactions, compositional data and fractals by means of distribution analysis. Weathering reactions represent the necessary transfer of heat and entropy to the environment in geochemical cycles. Compositional data express the relative abundance of chemical elements/species in a given total (i.e. volume or weight). Fractals are temporal or spatial objects with self-similarity and scale-invariance, so that internal structures repeat themselves over multiple levels of magnification or scales of measurement. Gibbs's free energy and the application of the Law Mass Action can be used to model weathering reactions, under the hypothesis of chemical equilibrium. Compositional data are obtained in the analytical phase after the determination of the concentrations of chemicals in sampled solid, liquid or gaseous materials. Fractals can be measured by using their fractal dimensions. In this paper, the presence of fractal structures is observed when the frequency distribution of isometric log-ratio coordinates is investigated, showing the logarithm of the cumulative number of samples exceeding a certain coordinate value plotted against the coordinate value itself. Isometric log-ratio coordinates (or balances) were constructed by using the sequential binary partition (SBP) method. The balances were identified to maintain, as far as possible, the similarity with a corresponding weathering reaction affecting the Arno river catchment (Tuscany, central Italy) as described by the Law of Mass Action. The emergence of fractal structures indicates the presence of dissipative systems, which require complexity, large numbers of inter-connected elements and stochasticity. - Highlights: • Frequency distribution analysis links compositional data and fractals. • Isometric log-ratio coordinates simulate chemical reactions in weathering processes. • Fractal

Effect of the Ti/B4C mole ratio on the reaction products and reaction mechanism in an Al–Ti–B4C powder mixture

International Nuclear Information System (INIS)

Zhang, Jingjing; Lee, Jung-Moo; Cho, Young-Hee; Kim, Su-Hyeon; Yu, Huashun

2014-01-01

The effect of the Ti/B 4 C mole ratio on the fabrication behavior of Al composites is investigated using Al–Ti–B 4 C powder mixtures as reactants. The quick spontaneous infiltration (QSI) process combined with the combustion reaction and DTA analysis were used. According to the thermodynamic predictions, which are verified in the experimental results, TiB 2 is formed in all the samples whereas TiC is only formed in reactants with a Ti/B 4 C mole ratio of more than two. The C atoms from the reacted B 4 C do not move into TiC but instead they move into Al 3 BC or Al 4 C 3 when the Ti/B 4 C mole ratio is less than two. In addition, the reaction mechanism with a Ti/B 4 C mole ratio of 0.75 is investigated extensively. - Highlights: • The critical role of the Ti/B 4 C mole ratio on the reaction products of Al–Ti–B 4 C was studied using experiments. • The experimental results are also supported by thermodynamic calculations presented in this paper. • The reaction mechanism with a Ti/B 4 C mole ratio of 0.75 is investigated extensively

Thermodynamic stability of elementary chemical reactions proceeding at finite rates revisited using Lyapunov function analysis

International Nuclear Information System (INIS)

Burande, Chandrakant S.; Bhalekar, Anil A.

2005-01-01

The thermodynamic stability of a few representative elementary chemical reactions proceeding at finite rates has been investigated using the recently proposed thermodynamic Lyapunov function and following the steps of Lyapunov's second method (also termed as the direct method) of stability of motion. The thermodynamic Lyapunov function; L s , used herein is the excess rate of entropy production in the thermodynamic perturbation space, which thereby inherits the dictates of the second law of thermodynamics. This Lyapunov function is not the same as the excess entropy rate that one encounters in thermodynamic (irreversible) literature. The model chemical conversions studied in this presentation are A+B→v x X and A+B↔ν x X. For the sake of simplicity, the thermal effects of chemical reactions have been considered as not adding to the perturbation as our main aim was to demonstrate how one should use systematically the proposed thermodynamic Lyapunov function following the steps of Lyapunov's second method of stability of motion. The domains of thermodynamic stability under the constantly acting small disturbances, thermodynamic asymptotic stability and thermodynamic instability in these model systems get established

Failure is an option: Reactions to failure in elementary engineering design projects

Science.gov (United States)

Johnson, Matthew M.

Recent reform documents in science education have called for teachers to use epistemic practices of science and engineering researchers to teach disciplinary content (NRC, 2007; NRC, 2012; NGSS Lead States, 2013). Although this creates challenges for classroom teachers unfamiliar with engineering, it has created a need for high quality research about how students and teachers engage in engineering activities to improve curriculum development and teaching pedagogy. While framers of the Next Generation Science Standards (NRC, 2012; NGSS Lead States 2013) focused on the similarities of the practices of science researchers and engineering designers, some have proposed that engineering has a unique set of epistemic practices, including improving from failure (Cunningham & Carlsen, 2014; Cunningham & Kelly, in review). While no one will deny failures occur in science, failure in engineering is thought of in fundamentally different ways. In the study presented here, video data from eight classes of elementary students engaged in one of two civil engineering units were analyzed using methods borrowed from psychology, anthropology, and sociolinguistics to investigate: 1) the nature of failure in elementary engineering design; 2) the ways in which teachers react to failure; and 3) how the collective actions of students and teachers support or constrain improvement in engineering design. I propose new ways of considering the types and causes of failure, and note three teacher reactions to failure: the manager, the cheerleader, and the strategic partner. Because the goal of iteration in engineering is improvement, I also studied improvement. Students only systematically improve when they have the opportunity, productive strategies, and fair comparisons between prototypes. I then investigate the use of student engineering journals to assess learning from the process of improvement after failure. After discussion, I consider implications from this work as well as future research

A shock tube study of the branching ratios of propene + OH reaction

KAUST Repository

Badra, Jihad; Khaled, Fathi; Giri, Binod Raj; Farooq, Aamir

2014-01-01

coefficients are discussed and rationalized for the site-specific H-abstraction by the OH radical. The first experimental measurements for the branching ratio of the title reaction are reported and compared with transition state theory calculations. The allylic

CrossRef Antiproton Flux, Antiproton-to-Proton Flux Ratio, and Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station

CERN Document Server

Aguilar, M; Alpat, B; Ambrosi, G; Arruda, L; Attig, N; Aupetit, S; Azzarello, P; Bachlechner, A; Barao, F; Barrau, A; Barrin, L; Bartoloni, A; Basara, L; Başeǧmez-du Pree, S; Battarbee, M; Battiston, R; Bazo, J; Becker, U; Behlmann, M; Beischer, B; Berdugo, J; Bertucci, B; Bindi, V; Boella, G; de Boer, W; Bollweg, K; Bonnivard, V; Borgia, B; Boschini, M  J; Bourquin, M; Bueno, E  F; Burger, J; Cadoux, F; Cai, X  D; Capell, M; Caroff, S; Casaus, J; Castellini, G; Cernuda, I; Cervelli, F; Chae, M  J; Chang, Y  H; Chen, A  I; Chen, G  M; Chen, H  S; Cheng, L; Chou, H  Y; Choumilov, E; Choutko, V; Chung, C  H; Clark, C; Clavero, R; Coignet, G; Consolandi, C; Contin, A; Corti, C; Coste, B; Creus, W; Crispoltoni, M; Cui, Z; Dai, Y  M; Delgado, C; Della Torre, S; Demirköz, M  B; Derome, L; Di Falco, S; Dimiccoli, F; Díaz, C; von Doetinchem, P; Dong, F; Donnini, F; Duranti, M; D'Urso, D; Egorov, A; Eline, A; Eronen, T; Feng, J; Fiandrini, E; Finch, E; Fisher, P; Formato, V; Galaktionov, Y; Gallucci, G; García, B; García-López, R  J; Gargiulo, C; Gast, H; Gebauer, I; Gervasi, M; Ghelfi, A; Giovacchini, F; Goglov, P; Gómez-Coral, D  M; Gong, J; Goy, C; Grabski, V; Grandi, D; Graziani, M; Guerri, I; Guo, K  H; Habiby, M; Haino, S; Han, K  C; He, Z  H; Heil, M; Hoffman, J; Hsieh, T  H; Huang, H; Huang, Z  C; Huh, C; Incagli, M; Ionica, M; Jang, W  Y; Jinchi, H; Kang, S  C; Kanishev, K; Kim, G  N; Kim, K  S; Kirn, Th; Konak, C; Kounina, O; Kounine, A; Koutsenko, V; Krafczyk, M  S; La Vacca, G; Laudi, E; Laurenti, G; Lazzizzera, I; Lebedev, A; Lee, H  T; Lee, S  C; Leluc, C; Li, H  S; Li, J  Q; Li, Q; Li, T  X; Li, W; Li, Z  H; Li, Z  Y; Lim, S; Lin, C  H; Lipari, P; Lippert, T; Liu, D; Liu, Hu; Lu, S  Q; Lu, Y  S; Luebelsmeyer, K; Luo, F; Luo, J  Z; Lv, S  S; Majka, R; Mañá, C; Marín, J; Martin, T; Martínez, G; Masi, N; Maurin, D; Menchaca-Rocha, A; Meng, Q; Mo, D  C; Morescalchi, L; Mott, P; Nelson, T; Ni, J  Q; Nikonov, N; Nozzoli, F; Nunes, P; Oliva, A; Orcinha, M; Palmonari, F; Palomares, C; Paniccia, M; Pauluzzi, M; Pensotti, S; Pereira, R; Picot-Clemente, N; Pilo, F; Pizzolotto, C; Plyaskin, V; Pohl, M; Poireau, V; Putze, A; Quadrani, L; Qi, X  M; Qin, X; Qu, Z  Y; Räihä, T; Rancoita, P  G; Rapin, D; Ricol, J  S; Rodríguez, I; Rosier-Lees, S; Rozhkov, A; Rozza, D; Sagdeev, R; Sandweiss, J; Saouter, P; Schael, S; Schmidt, S  M; Schulz von Dratzig, A; Schwering, G; Seo, E  S; Shan, B  S; Shi, J  Y; Siedenburg, T; Son, D; Song, J  W; Sun, W  H; Tacconi, M; Tang, X  W; Tang, Z  C; Tao, L; Tescaro, D; Ting, Samuel C  C; Ting, S  M; Tomassetti, N; Torsti, J; Türkoğlu, C; Urban, T; Vagelli, V; Valente, E; Vannini, C; Valtonen, E; Vázquez Acosta, M; Vecchi, M; Velasco, M; Vialle, J  P; Vitale, V; Vitillo, S; Wang, L  Q; Wang, N  H; Wang, Q  L; Wang, X; Wang, X  Q; Wang, Z  X; Wei, C  C; Weng, Z  L; Whitman, K; Wienkenhöver, J; Willenbrock, M; Wu, H; Wu, X; Xia, X; Xiong, R  Q; Xu, W; Yan, Q; Yang, J; Yang, M; Yang, Y; Yi, H; Yu, Y  J; Yu, Z  Q; Zeissler, S; Zhang, C; Zhang, J; Zhang, J  H; Zhang, S  D; Zhang, S  W; Zhang, Z; Zheng, Z  M; Zhu, Z  Q; Zhuang, H  L; Zhukov, V; Zichichi, A; Zimmermann, N; Zuccon, P

2016-01-01

A precision measurement by AMS of the antiproton flux and the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on 3.49×105 antiproton events and 2.42×109 proton events. The fluxes and flux ratios of charged elementary particles in cosmic rays are also presented. In the absolute rigidity range ∼60 to ∼500  GV, the antiproton p¯, proton p, and positron e+ fluxes are found to have nearly identical rigidity dependence and the electron e− flux exhibits a different rigidity dependence. Below 60 GV, the (p¯/p), (p¯/e+), and (p/e+) flux ratios each reaches a maximum. From ∼60 to ∼500  GV, the (p¯/p), (p¯/e+), and (p/e+) flux ratios show no rigidity dependence. These are new observations of the properties of elementary particles in the cosmos.

Reaction kinetics aspect of U3O8 kernel with gas H2 on the characteristics of activation energy, reaction rate constant and O/U ratio of UO2 kernel

International Nuclear Information System (INIS)

Damunir

2007-01-01

The reaction kinetics aspect of U 3 O 8 kernel with gas H 2 on the characteristics of activation energy, reaction rate constant and O/U ratio of UO 2 kernel had been studied. U 3 O 8 kernel was reacted with gas H 2 in a reduction furnace at varied reaction time and temperature. The reaction temperature was varied at 600, 700, 750 and 850 °C with a pressure of 50 mmHg for 3 hours in gas N 2 atmosphere. The reation time was varied at 1, 2, 3 and 4 hours at a temperature of 750 °C using similar conditions. The reaction product was UO 2 kernel. The reaction kinetic aspect between U 3 O 8 and gas H 2 comprised the minimum activation energy (ΔE), the reaction rate constant and the O/U ratio of UO 2 kernel. The minimum activation energy was determined from a straight line slope of equation ln [{D b . R o {(1 - (1 - X b ) ⅓ } / (b.t.Cg)] = -3.9406 x 10 3 / T + 4.044. By multiplying with the straight line slope -3.9406 x 10 3 , the ideal gas constant (R) 1.985 cal/mol and the molarity difference of reaction coefficient 2, a minimum activation energy of 15.644 kcal/mol was obtained. The reaction rate constant was determined from first-order chemical reaction control and Arrhenius equation. The O/U ratio of UO 2 kernel was obtained using gravimetric method. The analysis result of reaction rate constant with chemical reaction control equation yielded reaction rate constants of 0.745 - 1.671 s -1 and the Arrhenius equation at temperatures of 650 - 850 °C yielded reaction rate constants of 0.637 - 2.914 s -1 . The O/U ratios of UO 2 kernel at the respective reaction rate constants were 2.013 - 2.014 and the O/U ratios at reaction time 1 - 4 hours were 2.04 - 2.011. The experiment results indicated that the minimum activation energy influenced the rate constant of first-order reaction and the O/U ratio of UO 2 kernel. The optimum condition was obtained at reaction rate constant of 1.43 s -1 , O/U ratio of UO 2 kernel of 2.01 at temperature of 750 °C and reaction time of 3

Isomeric cross-section ratios of some (n,2n) reactions at 14. 7 MeV

Energy Technology Data Exchange (ETDEWEB)

Garg, K C; Khurana, C S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

1979-08-01

Isomeric cross-section ratios of (n,2n) reactions at 14.7 MeV leading to the millisecond isomeric levels have been calculated theoretically using the statistical theory of nuclear reactions and the spin distribution form due to Bethe and Bloch. The theoretical ratios have been compared with the experimentally measured values in order to evaluate the spin cut-off parameter sigma. This parameter has been used to calculate the effective moment of inertia of the nucleus to draw useful conclusions from the results of present calculations.

Experimental and numerical reaction analysis on sodium-water chemical reaction field

International Nuclear Information System (INIS)

Deguchi, Yoshihiro; Takata, Takashi; Yamaguchi, Akira; Kikuchi, Shin; Ohshima, Hiroyuki

2015-01-01

In a sodium-cooled fast reactor (SFR), liquid sodium is used as a heat transfer fluid because of its excellent heat transport capability. On the other hand, it has strong chemical reactivity with water vapor. One of the design basis accidents of the SFR is the water leakage into the liquid sodium flow by a breach of heat transfer tubes. This process ends up damages on the heat transport equipment in the SFR. Therefore, the study on sodium-water chemical reactions is of paramount importance for security reasons. This study aims to clarify the sodium-water reaction mechanisms using an elementary reaction analysis. A quasi one-dimensional flame model is applied to a sodium-water counter-flow reaction field. The analysis contains 25 elementary reactions, which consist of 17 H_2-O_2 and 8 Na-H_2O reactions. Temperature and species concentrations in the counter-flow reaction field were measured using laser diagnostics such as LIF and CARS. The main reaction in the experimental conditions is Na+H_2O → NaOH+H and OH is produced by H_2O+H → H_2+OH. It is demonstrated that the reaction model in this study well explains the structure of the sodium-water counter-flow diffusion flame. (author)

Robotics Literacy Captivates Elementary Students.

Science.gov (United States)

Friedman, Madeleine

1986-01-01

Describes a robotics literacy course offered for elementary age children at Broward Community College (Florida) and discusses the motivation for offering such a course, the course philosophy and objectives, and participant reactions. A sampling of robots and robotics devices and some of their teaching applications are included. (MBR)

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.

Effect of the Ti/B{sub 4}C mole ratio on the reaction products and reaction mechanism in an Al–Ti–B{sub 4}C powder mixture

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jingjing [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250100 (China); Light Metal Division, Korea Institute of Materials Science, Changwon 642-831 (Korea, Republic of); Lee, Jung-Moo, E-mail: jmoolee@kims.re.kr [Light Metal Division, Korea Institute of Materials Science, Changwon 642-831 (Korea, Republic of); Cho, Young-Hee; Kim, Su-Hyeon [Light Metal Division, Korea Institute of Materials Science, Changwon 642-831 (Korea, Republic of); Yu, Huashun [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250100 (China)

2014-10-15

The effect of the Ti/B{sub 4}C mole ratio on the fabrication behavior of Al composites is investigated using Al–Ti–B{sub 4}C powder mixtures as reactants. The quick spontaneous infiltration (QSI) process combined with the combustion reaction and DTA analysis were used. According to the thermodynamic predictions, which are verified in the experimental results, TiB{sub 2} is formed in all the samples whereas TiC is only formed in reactants with a Ti/B{sub 4}C mole ratio of more than two. The C atoms from the reacted B{sub 4}C do not move into TiC but instead they move into Al{sub 3}BC or Al{sub 4}C{sub 3} when the Ti/B{sub 4}C mole ratio is less than two. In addition, the reaction mechanism with a Ti/B{sub 4}C mole ratio of 0.75 is investigated extensively. - Highlights: • The critical role of the Ti/B{sub 4}C mole ratio on the reaction products of Al–Ti–B{sub 4}C was studied using experiments. • The experimental results are also supported by thermodynamic calculations presented in this paper. • The reaction mechanism with a Ti/B{sub 4}C mole ratio of 0.75 is investigated extensively.

Investigations of elementary reactions of the methyl radical with the aid of laser magnetic resonance; Untersuchungen von Elementarreaktionen des Methylradikals mit Hilfe der Laser-Magnetischen-Resonanz

Energy Technology Data Exchange (ETDEWEB)

Deters, R.J.

1998-01-01

Selected elementary reactions of CH{sub 3} radicals in an isothermal flow system in the gaseous phase were investigated by means of LMR. [Deutsch] In dieser Arbeit wurden ausgewaehlte Elementarreaktionen von CH{sub 3}-Radikalen in einem isothermen Stroemungssystem in der Gasphase mit Hilfe der Laser-Magnetischen-Resonanz untersucht. (orig.)

Reaction Rate Distributions and Ratios in FR0 Assemblies 1, 2 and 3

Energy Technology Data Exchange (ETDEWEB)

Andersson, T L

1966-06-15

The spatial distribution of different reaction rates and reaction ratios in Assemblies 1, 2 and 3 of the fast reactor FR0 was measured by fission chamber scans and foil activation technique. Assemblies 1 and 2 had cores of undiluted fuel (uranium metal enriched to 20 % U{sup 235}) while the core of Assembly 3 was diluted with about 30 vol. % graphite. All the systems had a thick copper reflector, The experimental results were compared with calculated values obtained from DSN and TDC multigroup spectra and group cross-section sets for the reactions. Good agreement between experiment and calculations is generally obtained in the core region but in the reflector the neutron spectrum is calculated too hard.

Global Controllability of Chemical Reactions

OpenAIRE

Drexler, Dániel András; Tóth, János

2015-01-01

Controllability of chemical reactions is an important problem in chemical engineering science. In control theory, analysis of the controllability of linear systems is well-founded, however the dynamics of chemical reactions is usually nonlinear. Global controllability properties of chemical reactions are analyzed here based on the Lie-algebra of the vector fields associated to elementary reactions. A chemical reaction is controllable almost everywhere if all the reaction rate coefficients can...

Alcohol-to-acid ratio and substrate concentration affect product structure in chain elongation reactions initiated by unacclimatized inoculum.

Science.gov (United States)

Liu, Yuhao; Lü, Fan; Shao, Liming; He, Pinjing

2016-10-01

The objective of the study was to investigate whether the ratio of ethanol to acetate affects yield and product structure in chain elongation initiated by unacclimatized mixed cultures. The effect of varying the substrate concentration, while maintaining the same ratio of alcohol to acid, was also investigated. With a high substrate concentration, an alcohol to acid ratio >2:1 provided sufficient electron donor capacity for the chain elongation reaction. With an ethanol to acetate ratio of 3:1 (300mM total carbon), the highest n-caproate concentration (3033±98mg/L) was achieved during the stable phase of the reaction. A lower substrate concentration (150mM total carbon) gave a lower yield of products and led to reduced carbon transformation efficiency compared with other reaction conditions. The use of unacclimatized inoculum in chain elongation can produce significant amounts of odd-carbon-number carboxylates as a result of protein hydrolysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Special features of isomeric ratios in nuclear reactions induced by various projectile particles

Energy Technology Data Exchange (ETDEWEB)

Danagulyan, A. S.; Hovhannisyan, G. H., E-mail: hov-gohar@ysu.am; Bakhshiyan, T. M.; Martirosyan, G. V. [Yerevan State University (Armenia)

2016-05-15

Calculations for (p, n) and (α, p3n) reactions were performed with the aid of the TALYS-1.4 code. Reactions in which the mass numbers of target and product nuclei were identical were examined in the range of A = 44–124. Excitation functions were obtained for product nuclei in ground and isomeric states, and isomeric ratios were calculated. The calculated data reflect well the dependence of the isomeric ratios on the projectile type. A comparison of the calculated and experimental data reveals, that, for some nuclei in a high-spin state, the calculated data fall greatly short of their experimental counterparts. These discrepancies may be due to the presence of high-spin yrast states and rotational bands in these nuclei. Calculations involving various level-density models included in the TALYS-1.4 code with allowance for the enhancement of collective effects do not remove the discrepancies in the majority of cases.

The effects of reactants ratios, reaction temperatures and times on Maillard reaction products of the L-ascorbic acid/L-glutamic acid system

Directory of Open Access Journals (Sweden)

Yong-Yan ZHOU

2016-01-01

Full Text Available Abstract The transformation law of the Maillard reaction products with three different reactants ratios - equimolar reactants, excess L-glutamic acid and excess L-ascorbic acid reaction respectively, five different temperatures, and different time conditions for the L-ascorbic acid / L-glutamic acid system were investigated. Results showed that, the increase of the reaction time and temperature led to the increase of the browning products, uncoloured intermediate products, as well as aroma compounds. Compared with the equimolar reaction system, the excess L-ascorbic acid reaction system produced more browning products and uncoloured intermediate products, while the aroma compounds production remained the same. In the excess L-glutamic acid system, the uncoloured intermediate products increased slightly, the browning products remained the same, while the aroma compounds increased.

Thermonuclear reaction generation method and device

International Nuclear Information System (INIS)

Imazaki, Kazuo

1998-01-01

The present invention provides a method of and a device for causing thermonuclear reaction capable of obtaining extremely high profits (about 1000 times), capable of forming a target which is strong against instability upon implosion as a problem of an inertia process and capable of realizing utilization of nuclear fusion. Namely, elementary particles such as pion, muon and K particles are deposited a portion or some portion of thermonuclear fuel materials by using high energy ions and highly brilliant γ rays generated from a high energy accelerator. The thermonuclear fuel materials are compressed to high density. The nuclear fusion reaction is promoted to ignite and burn thermonuclear fuels. A portion of nuclear fuels is ignited selectively by the means. High profits can be obtained. Since there is no need to attain implosion rate required for self ignition of nuclear fuels, a target of low aspect ratio can be used. (I.S.)

HADES results in elementary reactions

Directory of Open Access Journals (Sweden)

Ramstein B.

2014-01-01

Full Text Available Recent results obtained with the HADES experimental set-up at GSI are presented with a focus on dielectron production and strangeness in pp and quasi-free np reactions. Perspectives related to the very recent experiment using the pion beam at GSI are also discussed.

Elementary operators - still not elementary?

Directory of Open Access Journals (Sweden)

Martin Mathieu

2016-01-01

Full Text Available Properties of elementary operators, that is, finite sums of two-sided multiplications on a Banach algebra, have been studied under a vast variety of aspects by numerous authors. In this paper we review recent advances in a new direction that seems not to have been explored before: the question when an elementary operator is spectrally bounded or spectrally isometric. As with other investigations, a number of subtleties occur which show that elementary operators are still not elementary to handle.

The Effect of Acetone Amount Ratio as Co-Solvent to Methanol in Transesterification Reaction of Waste Cooking Oil

Science.gov (United States)

Julianto, T. S.; Nurlestari, R.

2018-04-01

The production of biodiesel from waste cooking oil by transesterification reaction using acetone as co-solvent has been carried out. This research studied the optimal amount ratio of acetone as co-solvent to methanol in the transesterification process using homogeneous alkaline catalyst KOH 1% (w/w) of waste cooking oil at room temperature for 15 minutes of reaction time. Mole ratio of waste cooking oil to methanol is 1:12. Acetone was added as co-solvent in varied amount ratio to methanol are 1:4, 1:2, and 1:1, respectively. The results of fatty acid methyl esters (FAME) were analysed using GC-MS instrument. The results showed that the optimal ratio is 1:4 with 99.93% of FAME yield.

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

Dynamics of elementary processes in the gas phase O2 and CO

International Nuclear Information System (INIS)

Bacchus-Montabonel, M.C.; Tergiman, Y.S.; Vaeck, N.; Baloitcha, E.; Desouter-Lecomte, M.

2002-01-01

Complex reaction mechanisms are involved in the radiation of biomolecules, their dynamics may proceed by a series of elementary processes, induced often by a fast reaction step, followed by relaxation or reorganization of the molecular system. The time-dependent wave packet method tested on the Si 4+ + He system, provides a clear and physical insight into the dynamics of theses process. Photodissociation experiments were performed, in particular the dissociation of bromoacetylchloride Br-CH 2 -COCl, to study the competitive dissociation of C-Cl and C-Br bonds. The dissociation leaded preferentially to C- Cl breaking, although the C-Br bond is thermodynamically weaker. This result is in disagreement with statistical theories, as the branching ratio depends not only on the relative height of the corresponding barriers, but also on non-adiabatic transitions arising from interactions between the different excited states. The effects depends on the distance between the C=O and C-X chromophores and on the conforming molecule. (nevyjel)

Content knowledge of prospective elementary school teacher for fractional concepts

Science.gov (United States)

Pattimukay, N.; Juniati, D.; Budiarto, M. T.

2018-03-01

The aim of this study was to describe the content knowledge especially the concept of fraction of prospective elementary school teacher. The purpose of this study is to describe the content knowledge, especially the concept of fraction of prospective elementary school teacher. The subject of the study was one of prospective elementary school teacher of Pattimura University. This research is qualitative research. Data were collected through the provision of tests to explore the knowledge content of primary school teacher candidates about fractional concepts. Then continued with qualitative data analysis. The results of this study are as follows: that the prospective primary school teacher defines fractions as part of the whole if an object is divided into equal parts, so that the part that has been divided is part of the whole. Furthermore, the prospective elementary school teacher understood the fractions as division shown in two ways, namely the prospective elementary school teacher understood the fraction as a division operation, the primary school teacher candidate interpreted the fraction as a division when an object is divided be part of the same. Meanwhile, the fraction as a ratio is interpreted as the relationship between a pair of numbers. Then, the denominations are interpreted as a ratio between the numerator and the denominator of the same value. The prospective elementary school teacher also understands fractions of value when simplifying fractions. Primary school teacher candidates understand the concept of fractional operations.

George A. Towns Elementary School. Atlanta, Georgia

Science.gov (United States)

Burt, Ralph H.

1976-01-01

A project testing solar heating and cooling in an existing building, the George A. Towns Elementary School, is intended to provide information on system design and performance, allow the identification and correction of problems encountered in installing large units, and gauge community/user reaction to solar equipment. (Author/MLF)

Determination of the in vivo NAD:NADH ratio in Saccharomyces cerevisiae under anaerobic conditions, using alcohol dehydrogenase as sensor reaction.

Science.gov (United States)

Bekers, K M; Heijnen, J J; van Gulik, W M

2015-08-01

With the current quantitative metabolomics techniques, only whole-cell concentrations of NAD and NADH can be quantified. These measurements cannot provide information on the in vivo redox state of the cells, which is determined by the ratio of the free forms only. In this work we quantified free NAD:NADH ratios in yeast under anaerobic conditions, using alcohol dehydrogenase (ADH) and the lumped reaction of glyceraldehyde-3-phosphate dehydrogenase and 3-phosphoglycerate kinase as sensor reactions. We showed that, with an alternative accurate acetaldehyde determination method, based on rapid sampling, instantaneous derivatization with 2,4 diaminophenol hydrazine (DNPH) and quantification with HPLC, the ADH-catalysed oxidation of ethanol to acetaldehyde can be applied as a relatively fast and simple sensor reaction to quantify the free NAD:NADH ratio under anaerobic conditions. We evaluated the applicability of ADH as a sensor reaction in the yeast Saccharomyces cerevisiae, grown in anaerobic glucose-limited chemostats under steady-state and dynamic conditions. The results found in this study showed that the cytosolic redox status (NAD:NADH ratio) of yeast is at least one order of magnitude lower, and is thus much more reduced, under anaerobic conditions compared to aerobic glucose-limited steady-state conditions. The more reduced state of the cytosol under anaerobic conditions has major implications for (central) metabolism. Accurate determination of the free NAD:NADH ratio is therefore of importance for the unravelling of in vivo enzyme kinetics and to judge accurately the thermodynamic reversibility of each redox reaction. Copyright © 2015 John Wiley & Sons, Ltd.

Anomalous deuteron to hydrogen ratio in naturally occuring fission reactions and the possibility of deuteron disintegration

International Nuclear Information System (INIS)

Shaheen, M.; Ragheb, M.

1992-01-01

A hypothesis is presented for explaining the experimentally determined anomalous D/H ratio observed in the samples from the naturally occuring fission reaction in the Oklo phenomenon. No other explanation has been given, to the best knowledge, for the large difference between the measured D/H ratio in the Oklo samples and the expected values in a fission neutron spectrum. A multicomponent system consisting of hydrogen, deuterium, tritium and helium nuclei is considered. An analytical solution is derived and solved using as boundary conditions the experimentally determined value of the D/H ratio. The solution of the rate equations for hydrogen and deuteron concentrations, assuming a pure fission process without a deuteron sink term, yields a D/H ratio of 445 ppm for a reaction in which the fluence of neutrons is 10 21 n/cm 2 . This exceeds the experimentally observed value of 127 ppm, and the naturally occuring value of 150 ppm. Solving the same rate equations accounting for a deuterium sink term using a hypothesis of deuteron disintegration, and the experimentally observed value of 127 ppm yields a deuteron disintegration constant of 7.47*10 -14 s -1 . Deuteron disintegration would provide a neutron source, in addition to the fission neutrons, driving a subcritical chain reaction over an extended period of time. Relationship of the presented hypothesis to the Vlasov theory of an annihilation meteorite impact explosion explaining the experimentally observed anomalous 235 U/ 238 U ratio, and to the suggestion of deuteron disintegration as a possible explanation of some observations of deuterium dissociation in palladium and titanium electrodes is discussed. The tritium andhelium-3 rate equations are further solved under the deuteron disintegration hypothesis and the relationship of the present work to the work by JONES et al. is discussed. (author) 16 refs.; 7 figs.; 2 tabs

Molecular beam studies of reaction dynamics

International Nuclear Information System (INIS)

Lee, Yuan T.

1991-03-01

The major thrust of this research project is to elucidate detailed dynamics of simple elementary reactions that are theoretically important and to unravel the mechanism of complex chemical reactions or photochemical processes that play important roles in many macroscopic processes. Molecular beams of reactants are used to study individual reactive encounters between molecules or to monitor photodissociation events in a collision-free environment. Most of the information is derived from measurement of the product fragment energy, angular, and state distributions. Recent activities are centered on the mechanisms of elementary chemical reactions involving oxygen atoms with unsaturated hydrocarbons, the dynamics of endothermic substitution reactions, the dependence of the chemical reactivity of electronically excited atoms on the alignment of excited orbitals, the primary photochemical processes of polyatomic molecules, intramolecular energy transfer of chemically activated and locally excited molecules, the energetics of free radicals that are important to combustion processes, the infrared-absorption spectra of carbonium ions and hydrated hydronium ions, and bond-selective photodissociation through electric excitation

Molecular beam studies of reaction dynamics

Energy Technology Data Exchange (ETDEWEB)

Lee, Y.T. [Lawrence Berkeley Laboratory, CA (United States)

1993-12-01

The major thrust of this research project is to elucidate detailed dynamics of simple elementary reactions that are theoretically important and to unravel the mechanism of complex chemical reactions or photochemical processes that play important roles in many macroscopic processes. Molecular beams of reactants are used to study individual reactive encounters between molecules or to monitor photodissociation events in a collision-free environment. Most of the information is derived from measurement of the product fragment energy, angular, and state distributions. Recent activities are centered on the mechanisms of elementary chemical reactions involving oxygen atoms with unsaturated hydrocarbons, the dynamics of endothermic substitution reactions, the dependence of the chemical reactivity of electronically excited atoms on the alignment of excited orbitals, the primary photochemical processes of polyatomic molecules, intramolecular energy transfer of chemically activated and locally excited molecules, the energetics of free radicals that are important to combustion processes, the infrared-absorption spectra of carbonium ions and hydrated hydronium ions, and bond-selective photodissociation through electric excitation.

A Taste of Cooperativeness within an Elementary School.

Science.gov (United States)

McElroy, Karen B.

1989-01-01

The process of implementing cooperative learning techniques in an elementary school in Montgomery County, Maryland, is described. Discussed are: learning techniques used, such as Student Teams Achievement Divisions, Round Table, Think-Pair-Share, and the Trading Game; student and teacher reactions to cooperative learning; teacher recommendations;…

Effect of Mo/B atomic ratio on the properties of Mo2NiB2-based cermets

International Nuclear Information System (INIS)

Xie, Lang; Li, XiaoBo; Zhang, Dan; Yi, Li; Gao, XiaoQing; Xiangtan Univ.

2015-01-01

Using three elementary substances, Mo, Ni, and amorphous B as raw materials, four series of Mo 2 NiB 2 -based cermets with the Mo/B atomic ratio ranging from 0.9 to 1.2 were successfully prepared via reaction sintering. The effect of Mo/B atomic ratio on the microstructure and properties was studied for the cermets. The results indicate that there is a strong correlation between the Mo/B atomic ratio and properties. The transverse rupture strength of the cermets increases with an increase in Mo/B ratio and shows a maximum value of 1 872 MPa at an Mo/B atomic ratio of 1.1 and then decreases with increasing Mo/B atomic ratio. The hardness and the corrosion resistance of the cermets increase monotonically with an increase in Mo/B atomic ratio. In Mo-rich cermets with an atomic ratio of Mo/B above 1.1, a small amount Ni-Mo intermetallic compound is found precipitated at the interface of Mo 2 NiB 2 grains.

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…

Stereodynamics: From elementary processes to macroscopic chemical reactions

Energy Technology Data Exchange (ETDEWEB)

Kasai, Toshio [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Graduate School of Science, Department of Chemistry, Osaka University, Toyonaka, 560-0043 Osaka (Japan); Che, Dock-Chil [Graduate School of Science, Department of Chemistry, Osaka University, Toyonaka, 560-0043 Osaka (Japan); Tsai, Po-Yu [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Lin, King-Chuen [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Palazzetti, Federico [Scuola Normale Superiore, Pisa (Italy); Dipartimento di Chimica Biologia e Biotecnologie, Università di Perugia, 06123 Perugia (Italy); Aquilanti, Vincenzo [Dipartimento di Chimica Biologia e Biotecnologie, Università di Perugia, 06123 Perugia (Italy); Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Roma (Italy); Instituto de Fisica, Universidade Federal da Bahia, Salvador (Brazil)

2015-12-31

This paper aims at discussing new facets on stereodynamical behaviors in chemical reactions, i.e. the effects of molecular orientation and alignment on reactive processes. Further topics on macroscopic processes involving deviations from Arrhenius behavior in the temperature dependence of chemical reactions and chirality effects in collisions are also discussed.

Impact Parameter Dependence of the Double Neutron/Proton Ratio of Nucleon Emissions in Isotopic Reaction Systems

International Nuclear Information System (INIS)

Xun-Chao, Zhang; Gao-Chan, Yong; Bao-An, Li; Lie-Wen, Chen

2009-01-01

Within the transport model IBUU04, we investigate the double neutron/proton ratio of free nucleons taken from two reaction systems using two Sn isotopes at a beam energy of 50 MeV/nucleon and with impact parameters 2 fm, 4 fm and 8 fm, respectively. It is found that the double neutron/proton ratio from peripheral collisions is more sensitive to the density dependence of the symmetry energy than those from mid-central and central collisions. (nuclear physics)

Hydrogen electrode reaction: A complete kinetic description

International Nuclear Information System (INIS)

Quaino, P.M.; Gennero de Chialvo, M.R.; Chialvo, A.C.

2007-01-01

The kinetic description of the hydrogen electrode reaction (HER) in the whole range of overpotentials (-0.2 < η (V) < 0.40) is presented. The Volmer-Heyrovsky-Tafel mechanism was solved considering simultaneously the following items: (i) the diffusional contribution of the molecular hydrogen from and towards the electrode surface, (ii) the forward and backward reaction rates of each elementary step and (iii) a Frumkin type adsorption for the reaction intermediate. In order to verify the descriptive capability of the kinetic expressions derived, an experimental study of the HER was carried out on a rotating platinum disc electrode in acid solution. From the correlation of these results the elementary kinetic parameters were evaluated and several aspects related to the kinetic mechanism were discussed. Finally, the use of these kinetic expressions to interpret results obtained on microelectrodes is also analysed

Kinetics of elementary atom and radical reactions

International Nuclear Information System (INIS)

Gordon, R.J.

1990-06-01

During the past three years we have been working on four problems in the general area of gas phase kinetics and energy transfer of small molecules. These are: (1) measurements of the fine structure populations of ground state oxygen atoms produced in photodissociation reactions; (2) quenching of the Rydberg B ( 1 Σ + ) state of CO; (3) vibrational relaxation of highly excited molecules; and (4) kinetics of hydrogen molecules. The first two topics, which involve transitions between different electronic states of the parent molecule, are a departure from our previous research interests. In the accompanying renewal proposal we discuss plans to pursue these new topics vigorously during the coming year. The third topic is a continuation of our long interest in the energy dependence of the rates laws governing vibrational-to-translational energy transfer of molecules having large initial amounts of vibrational excitation. The final topic is a continuation of our studies of the reaction of O( 3 P) + H 2 . In this work we measured the rate constant for the reaction O( 3 P) with deuterium and also analyzed spectroscopically different sources of vibrationally excited hydrogen for possible future work. We discuss each of these four studies in the following sections

Automated Discovery of New Chemical Reactions and Accurate Calculation of Their Rates

Science.gov (United States)

2015-06-02

chemistry calculations are run. The product matrices P are obtained and converted to block structure by simple linear algebra operations...in the system, i.e. 0 , =∑ ji ija Usually in elementary reactions |aij|ɛ since the change by two implies a significant chemical process, for...instance, formation or rupture of a double bond in a single elementary step. After applying the reaction matrix A, the product matrix P can then be

Isomeric cross section ratios in 55Mn(α, n)58m,gCo reaction

International Nuclear Information System (INIS)

Long Xianguan; He Fuqing; Peng Xiufen; Liu Mantian

1989-01-01

The isomeric cross section ratios in 55 Mn(α, n) 58m,g Co reaction are measured for incident alpha-particle energies ranging from 10.4 to 26.5 MeV by using activation method and stacked-foil technique. The measured values are compared with theoretical calculations performed by using Huizenga and Vandenbosch method and the values of spin cutoff factor are obtained for product nucleus 58 Co

Neutron to proton ratios of quasiprojectile and midrapidity emission in the 58Ni+58Ni reaction at 52 MeV/nucleon

International Nuclear Information System (INIS)

Theriault, D.; Vallee, A.; Gingras, L.; Larochelle, Y.; Roy, R.; April, A.; Beaulieu, L.; Grenier, F.; Lemieux, F.; Moisan, J.; St-Pierre, C.; Turbide, S.; Samri, M.; Borderie, B.; Rivet, M. F.; Bougault, R.; Colin, J.; Cussol, D.; Durand, D.; Lecolley, J.F.

2005-01-01

By combining data from a charged particle 58 Ni+ 58 Ni experiment at 52 MeV/nucleon with an 36 Ar+ 58 Ni experiment at 50 MeV/nucleon for which free neutrons have been detected, an increase in the neutron to proton ratio of the whole nuclear material at midrapidity has been experimentally observed in the reaction 58 Ni+ 58 Ni at 52 MeV/nucleon. The neutron-to-proton ratio of the quasi-projectile emission is analyzed for the same reactions and is seen to decrease below the ratio of the initial system. Those observations suggest that an asymmetric exchange of neutrons and protons between the quasiprojectile and the midrapidity region exists

Reactivity and reaction rate ratio changes with moderator voidage in a light water high converter reactor lattice

International Nuclear Information System (INIS)

Chawla, R.; Gmuer, K.; Hager, H.; Seiler, R.

1986-01-01

Integral reaction rate ratios and other k ∞ related parameters have been measured in the first three cores of the experimental program on light water high converter reactor (LWHCR) test lattices in the PROTEUS reactor. The reference tight-pitch lattice consisted of two rod types, with an average fissile-plutonium enrichment of 6% and a fuel/moderator ratio of 2.0. The moderators were H 2 O, Dowtherm (simulating an H 2 O voidage of 42.5%), and air (100% void). Comparisons of the measured parameters have been made with calculational results based mainly on the use of two separate codes and their associated data libraries, namely, WIMS-D and EPRI-CPM. A reconstruction of individual components of the k-infinity void coefficient has been carried out on the basis of the measured changes with voidage of the various reaction rate ratios, as well as of k-infinity itself. The subsequent more detailed comparisons between experiment and calculation should provide a useful basis for resolving the conflicting calculational results that have been reported in the past for the void coefficient characteristics of LWHCRs. (author)

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}.

A Case of Preservice Elementary Teachers Exploring, Retelling, and Reframing.

Science.gov (United States)

Nelson, Michael

2001-01-01

Presents preservice elementary teachers' frames (points of view) on science curriculum. Uses Carl Sagan's text, "The Demon Haunted World: Science as a Candle in the Dark". Explores how students retelling their reactions to experiences of their own design might influence their awareness of beliefs in general and reconsideration of…

Chemical modeling of irreversible reactions in nuclear waste-water-rock systems

International Nuclear Information System (INIS)

Wolery, T.J.

1981-02-01

Chemical models of aqueous geochemical systems are usually built on the concept of thermodynamic equilibrium. Though many elementary reactions in a geochemical system may be close to equilibrium, others may not be. Chemical models of aqueous fluids should take into account that many aqueous redox reactions are among the latter. The behavior of redox reactions may critically affect migration of certain radionuclides, especially the actinides. In addition, the progress of reaction in geochemical systems requires thermodynamic driving forces associated with elementary reactions not at equilibrium, which are termed irreversible reactions. Both static chemical models of fluids and dynamic models of reacting systems have been applied to a wide spectrum of problems in water-rock interactions. Potential applications in nuclear waste disposal range from problems in geochemical aspects of site evaluation to those of waste-water-rock interactions. However, much further work in the laboratory and the field will be required to develop and verify such applications of chemical modeling

Modelling of elementary kinetics of H2 and CO oxidation on ceria pattern cells

International Nuclear Information System (INIS)

Patel, HC; Tabish, AN; Aravind, PV

2015-01-01

Elementary kinetic mechanisms of fuel oxidation on ceria have not been dealt with in detail in literature. An elementary kinetic model is developed considering charge transfer and adsorption steps for electrochemical H 2 and CO oxidation on ceria. The reaction chemistry is solved by fitting previously obtained impedance spectra for H 2 and CO oxidation on ceria. The rate determining step is found to be the charge transfer rather than the adsorption for both H 2 and CO. A method is presented to extend the kinetics obtained from pattern anodes to macroscopic simulations in which the activation overvoltage can be calculated on the basis of elementary kinetics.

Latest AMS Results on elementary particles in cosmic rays

Science.gov (United States)

Kounine, Andrei; AMS Collaboration

2017-01-01

AMS-02 is a particle physics detector collecting data on the International Space Station since May 2011. Precision measurements of all elementary charged cosmic ray particles have been performed by AMS using a data sample of 85 billion cosmic ray events collected during the first five years of operations on the Station. The latest AMS results on the fluxes and flux ratios of the elementary cosmic ray particles are presented. They show unique features that require accurate theoretical interpretation as to their origin, be it from dark matter collisions or new astrophysical sources. On behalf of the AMS Collaboration.

The major/minor concept: dependence of the selectivity of homogeneously catalyzed reactions on reactivity ratio and concentration ratio of the intermediates.

Science.gov (United States)

Schmidt, Thomas; Dai, Zhenya; Drexler, Hans-Joachim; Hapke, Marko; Preetz, Angelika; Heller, Detlef

2008-07-07

The homogeneously catalyzed asymmetric hydrogenation of prochiral olefins with cationic Rh(I) complexes is one of the best-understood selection processes. For some of the catalyst/substrate complexes, experimental proof points out the validation of the major/minor principle; the concentration-deficient minor substrate complex, which has very high reactivity, yields the excess enantiomer. As exemplified by the reaction system of [Rh(dipamp)(MeOH)2]+/methyl (Z)-alpha-acetamidocinnamate (dipamp=1,2-bis((o-methoxyphenyl)phenylphosphino)ethane), all six of the characteristic reaction rate constants have been previously identified. Recently, it was found that the major substrate complex can also yield the major enantiomer (lock-and-key principle). The differential equation system that results from the reaction sequence can be solved numerically for different hydrogen partial pressures by including the known equilibrium constants. The result displays the concentration-time dependence of all species that exist in the catalytic cycle. On the basis of the known constants as well as further experimental evidence, this work focuses on the examination of all principal possibilities resulting from the reaction sequence and leading to different results for the stereochemical outcome. From the simulation, the following conclusions can be drawn: 1) When an intermediate has extreme reactivity, its stationary concentration can become so small that it can no longer be the source of product selectivity; 2) in principle, the major/minor and lock-and-key principles can coexist depending on the applied pressure; 3) thermodynamically determined intermediate ratios can be completely converted under reaction conditions for a selection process; and 4) the increase in enantioselectivity with increasing hydrogen partial pressure, a phenomenon that is experimentally proven but theoretically far from being well-understood, can be explained by applying both the lock-and-key as well as the major

Total cross-sections for reactions of high energy particles (including elastic, topological, inclusive and exclusive reactions). Subvol. b

International Nuclear Information System (INIS)

Schopper, H.; Moorhead, W.G.; Morrison, D.R.O.

1988-01-01

The aim of this report is to present a compilation of cross-sections (i.e. reaction rates) of elementary particles at high energy. The data are presented in the form of tables, plots and some fits, which should be easy for the reader to use and may enable him to estimate cross-sections for presently unmeasured energies. We have analyzed all the data published in the major Journals and Reviews for momenta of the incoming particles larger than ≅ 50 MeV/c, since the early days of elementary particle physics and, for each reaction, we have selected the best cross-section data available. We have restricted our attention to integrated cross-sections, such as total cross-sections, exclusive and inclusive cross-sections etc., at various incident beam energies. We have disregarded data affected by geometrical and/or kinematical cuts which would make them not directly comparable to other data at different energies. Also, in the case of exclusive reactions, we have left out data where not all of the particles in the final state were unambiguously identified. This work contains reactions induced by neutrinos, gammas, charged pions, kaons, nucleons, antinucleons and hyperons. (orig./HSI)

Isomeric ratios in photonuclear reactions of molybdenum isotopes induced by bremsstrahlung in the giant dipole resonance region

International Nuclear Information System (INIS)

Tran Duc Thiep; Truong Thi An; Phan Viet Cuong; Nguyen The Vinh; Bui Minh Hue; Belov, A.G.; Maslov, O.D.; Mishinsky, G.V.; Zhemenik, V.I.

2017-01-01

We have determined the isomeric ratios of isomeric pairs "9"7"m","gNb, "9"5"m","gNb and "9"1"m","gMo produced in "9"8Mo(γ, p)"9"7"m","gNb, "9"6Mo(γ, p)"9"5"m","gNb and "9"2Mo(γ, n)"9"1"m","gMo photonuclear reactions in the giant dipole resonance (GDR) region by the activation method. The results were analyzed, discussed and compared with the similar data from literature to examine the role of excitation energy, neutron configuration, channel effect, and direct and pre-equilibrium processes in (γ, p) photonuclear reactions. In this work the isomeric ratios for "9"7"m","gNb from 14 to 19 MeV, for "1"9"5"m","gNb from 14 to 24 MeV except 20 and 23.5 MeV and for "9"1"m","gMo at 14 and 15 MeV were first measured.

Is an elementary particle really: (i) a particle? (ii) elementary?

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. Is an elementary particle really: (i) a particle? (ii) elementary? Over centuries, naïve notions about this have turned out incorrect. Particles are not really pointlike. The word elementary is not necessarily well-defined. Notes:

Evidence for the characterization of heavy-ion reactions by the ratio E/B

International Nuclear Information System (INIS)

Mathews, G.J.; Wozniak, G.J.; Schmitt, R.P.; Moretto, L.G.

1977-01-01

The connection between the characteristic features of reactions involving very heavy target-projectile combinations (e.g. 86 Kr + 197 Au) and lighter systems (e.g. 40 Ar + sup(nat)Ag) is discussed. Evidence for an impirical scaling law based upon the ratio E/B (center-of-mass kinetic energy to Coulomb barrier) is presented. This scaling is justified in terms of semiquantitative arguments whereby the different charge and angular distribution patterns from light and heavy target-projectile combinations are correlated with different lifetime regimes for the 'intermediate complex' as it diffuses along the mass-asymmetry coordinate. (orig.) [de

Elementary school on the move– moving in elementary school

Directory of Open Access Journals (Sweden)

Reiner Hildebrandt-Stramann

2008-06-01

Full Text Available Elementary school in Germany has changed during the last five years because, among other reasons, movement has entered it. The title's pun calls attention for two lines of work that characterize school pedagogy contemporary discussion. One of these lines is related to the last 15 years changing process at elementary school: it states that elementary school must be a learning and living place for children. The other line is related to movement pedagogy processes, which has been achieving higher and higher dimensions. Elementary school must be seen from movement point of view and must be transformed in a place for movement.

The Sandy Hook Elementary School shooting as tipping point

Science.gov (United States)

Shultz, James M; Muschert, Glenn W; Dingwall, Alison; Cohen, Alyssa M

2013-01-01

Among rampage shooting massacres, the Sandy Hook Elementary School shooting on December 14, 2012 galvanized public attention. In this Commentary we examine the features of this episode of gun violence that has sparked strong reactions and energized discourse that may ultimately lead toward constructive solutions to diminish high rates of firearm deaths and injuries in the United States. PMID:28228989

Elementary Mathematics Leaders

Science.gov (United States)

Fennell, Francis; Kobett, Beth McCord; Wray, Jonathan A.

2013-01-01

Elementary school mathematics leaders often come to the realization that their position, however titled and determined, although dedicated to addressing needs in math teaching and learning, also entails and directly involves leadership. Elementary school math specialists/instructional leaders (referenced here as elementary mathematics leaders, or…

Chemical reaction on solid surface observed through isotope tracer technique

International Nuclear Information System (INIS)

Tanaka, Ken-ichi

1983-01-01

In order to know the role of atoms and ions on solid surfaces as the partners participating in elementary processes, the literatures related to the isomerization and hydrogen exchanging reaction of olefines, the hydrogenation of olefines, the metathesis reaction and homologation of olefines based on solid catalysts were reviewed. Various olefines, of which the hydrogen atoms were substituted with deuterium at desired positions, were reacted using various solid catalysts such as ZnO, K 2 CO 3 on C, MoS 2 (single crystal and powder) and molybdenum oxide (with various carriers), and the infra-red spectra of adsorbed olefines on catalysts, the isotope composition of reaction products and the production rate of the reaction products were measured. From the results, the bonding mode of reactant with the atoms and ions on solid surfaces, and the mechanism of the elementary process were considered. The author emphasized that the mechanism of the chemical reaction on solid surfaces and the role of active points or catalysts can be made clear to the considerable extent by combining isotopes suitably. (Yoshitake, I.)

A shock tube study of the branching ratios of propene + OH reaction

KAUST Repository

Badra, Jihad

2014-12-01

Absolute rate coefficients for the reaction of the OH radical with propene (C3H6) and five deuterated isotopes, propene-1-D1 (CDHCHCH3), propene-1,1-D2 (CD2CHCH3), propene-1,1,2-D3 (CD2CDCH3), propene-3,3,3-D3 (CH2CHCD3), and propene-D6 (C3D6), were measured behind reflected shock waves over the temperature range of 818-1460 K and pressures near 1 atm. The reaction progress was followed by monitoring the OH radical near 306.7 nm using UV laser absorption. Kinetic isotope effects in the measured rate coefficients are discussed and rationalized for the site-specific H-abstraction by the OH radical. The first experimental measurements for the branching ratio of the title reaction are reported and compared with transition state theory calculations. The allylic H-atom abstraction of propene by OH radicals was found to be the most dominant reaction pathway followed by propen-1-yl and propen-2-yl channels over the entire temperature range of this study. The derived Arrhenius expressions for various site-specific rate coefficients over 818-1442 K are (the subscript in the rate coefficient identifies the position of H or D atom according to the IUPAC nomenclature of alkenes):k3,H = 2.32 × 10-11 exp(-2341 K/T) cm3 molecule-1 s-1k3,D = 1.96 × 10-11 exp(-2420 K/T) cm3 molecule-1 s-1k1,H = 1.39 × 10-11 exp(-2270 K/T) cm3 molecule-1 s-1k1,D = 1.95 × 10-11 exp(-2868 K/T) cm3 molecule-1 s-1k2,H = 7.2 × 10-12 exp(-2282 K/T) cm3 molecule-1 s-1k2,D = 7.69 × 10-12 exp(-2575 K/T) cm3 molecule-1 s-1 This journal is

Exchange reaction between hydrogen and deuterium. I. Importance of surface reactions in the steady-state mechanism

Energy Technology Data Exchange (ETDEWEB)

Marteau, C; Gaillard-Cusin, F; James, H [Centre National de la Recherche Scientifique, 45 - Orleans-la-Source (France). Centre de Recherches sur la Chimie de Combustion et des Hautes Temperatures

1978-05-01

Investigation of heterogeneous initiation process of gas phase linear chain reactions is carried out through the study of H/sub 2/-D/sub 2/ exchange reaction. Experimental data under study concern mainly the stationary rate of HD formation and the prestationary proceeding. Steady-state method accounts for the first one of these data; it allows to clearly compare the wall process part to the part played by the homogeneous chain reaction towards HD formation. Activation energy of exchange elementary step between chemisorbed hydrogen (on silica) and gaseous deuterium has been evaluated: Esub(e1)=52+-1 Kcal/mole.

THE CONCEPT OF VOCATIONAL TRAINING OF FUTURE ELEMENTARY SCHOOL TEACHER TO INFORMATICS TRAINING

Directory of Open Access Journals (Sweden)

Olena Sagan

2016-09-01

Full Text Available In the article the problem of professional training of future elementary school teacher to teach Informatics of junior schoolchild is revealed. Rapid development of information and communication technologies actualizes the high-quality requirements to informational competent members of society. Transformation of content of primary education, namely putting Informatics in the curricula, exerted impact on a social request of the elementary school teacher who doesn’t only thoroughly use means of information technologies, but also teaches Informatics as invariant discipline of elementary school. In work it is designed the methodical model of training of future elementary school teacher for teaching Informatics, its purpose is forming of methodology informational competence at future elementary school teacher, which is based on theoretical and practical readiness for teaching Informatics of junior schoolchild and is shown in abilities to organize of the teaching and educational process. Finding of a ratio of essential results of training in higher education institution and general and professional competences which were determined by means of expert evaluations became a basis of a substantial component of system. We design the expected result in the form of competence-based model of future elementary school teacher in a perspective of its preparation for the decision the informational and the methodology-informational tasks of elementary school.

Isobaric yield ratios and the symmetry energy in heavy-ion reactions near the Fermi energy

International Nuclear Information System (INIS)

Huang, M.; Chen, Z.; Kowalski, S.; Ma, Y. G.; Wada, R.; Hagel, K.; Barbui, M.; Bottosso, C.; Materna, T.; Natowitz, J. B.; Qin, L.; Rodrigues, M. R. D.; Sahu, P. K.; Keutgen, T.; Bonasera, A.; Wang, J.

2010-01-01

The relative isobaric yields of fragments produced in a series of heavy-ion-induced multifragmentation reactions have been analyzed in the framework of a modified Fisher model, primarily to determine the ratio of the symmetry energy coefficient to the temperature, a sym /T, as a function of fragment mass A. The extracted values increase from 5 to ∼16 as A increases from 9 to 37. These values have been compared to the results of calculations using the antisymmetrized molecular dynamics (AMD) model together with the statistical decay code gemini. The calculated ratios are in good agreement with those extracted from the experiment. In contrast, the values extracted from the ratios of the primary isobars from the AMD model calculation are ∼4 to 5 and show little variation with A. This observation indicates that the value of the symmetry energy coefficient derived from final fragment observables may be significantly different than the actual value at the time of fragment formation. The experimentally observed pairing effect is also studied within the same simulations. The Coulomb coefficient is also discussed.

Automotive exhaust gas conversion: from elementary step kinetics to prediction of emission dynamics

NARCIS (Netherlands)

Hoebink, J.H.B.J.; Harmsen, J.M.A.; Balenovic, M.; Backx, A.C.P.M.; Schouten, J.C.

2001-01-01

Elementary step based kinetics show a high added value to describe the performance of catalytic exhaust gas converters under dynamic conditions, as demonstrated with a Euro test cycle. Combination of such kinetic models for individual global reactions covers the mutual interactions via common

Does exposure to GSM 900 MHz mobile phone radiation affect short-term memory of elementary school students?

Science.gov (United States)

Movvahedi, M M; Tavakkoli-Golpayegani, A; Mortazavi, S A R; Haghani, M; Razi, Z; Shojaie-Fard, M B; Zare, M; Mina, E; Mansourabadi, L; Nazari-Jahromi; Safari, A; Shokrpour, N; Mortazavi, S M J

2014-05-01

Now-a-days, children are exposed to mobile phone radiation at a very early age. We have previously shown that a large proportion of children in the city of Shiraz, Iran use mobile phones. Furthermore, we have indicated that the visual reaction time (VRT) of university students was significantly affected by a 10 min real/sham exposure to electromagnetic fields emitted by mobile phone. We found that these exposures decreased the reaction time which might lead to a better response to different hazards. We have also revealed that occupational exposures to radar radiations decreased the reaction time in radar workers. The purpose of this study was to investigate whether short-term exposure of elementary school students to radiofrequency (RF) radiation leads to changes in their reaction time and short-term memory. A total of 60 elementary school children ages ranging from 8 to 10 years studying at a public elementary school in Shiraz, Iran were enrolled in this study. Standardized computer-based tests of VRT and short-term memory (modified for children) were administered. The students were asked to perform some preliminary tests for orientation with the VRT test. After orientation, to reduce the random variation of measurements, each test was repeated ten times in both real and sham exposure phases. The time interval between the two subsequent sham and real exposure phases was 30 min. The mean ± standard deviation reaction times after a 10 min talk period and after a 10 min sham exposure (switched off mobile) period were 249.0 ± 82.3 ms and 252.9 ± 68.2 ms (P = 0.629), respectively. On the other hand, the mean short-term memory scores after the talk and sham exposure periods were 1062.60 ± 305.39, and 1003.84 ± 339.68 (P = 0.030), respectively. To the best of our knowledge, this is the first study to show that short-term exposure of elementary school students to RF radiation leads to the better performance of their short-term memory.

Transverse Characteristics of Hadron Production in Elementary and Nuclear Collisions at the CERN SPS Energies

CERN Document Server

AUTHOR|(CDS)2076476; Bialkowska, H

2004-01-01

A comprehensive study of transverse phenomena at CERN-SPS energies has been performed using data collected by the NA49 experiment. Results on p, p, pi+ and pi- production in elementary hadronic interactions (p + p, pi+ +p and pi- + p) as well as in nuclear collisions (centrality-defined p + Pb, C + C, Si + Si And Pb + Pb) are presented. The dependence of transverse momentum spectra, and in particular the - xF correlations, on particle species, collision energy, size and structure of the colliding objects has been investigated. Particle composition, in terms of the nuclear modification factors RpA (pT) for different xF regions – and particle ratios, has been also studied. The whole set of experimental data puts strong constraints on theoretical models aiming at the description of hadron production in the studied reactions.

Properties of the elementary KN and anti KN interactions

International Nuclear Information System (INIS)

Dover, C.B.

1979-01-01

Kaon beams offer exciting prospects for the study of both nuclear and hypernuclear physics. Experiments on hypernucleus formation via the (K - ,π - ) reaction, as well as elastic and inelastic scattering of K +- from nuclei, are already underway. The theoretical analysis of such experiments requires an understanding of the underlying two-body K +- n interaction. The main features of these elementary amplitudes, as revealed through phase shift analyses and meson exchange model are reviewed. It is indicated how the properties of the two body interaction (isospin dependence, Y* and Z* resonance formation, strangeness exchange, etc.) are reflected in reactions induced by kaons in nuclei. 81 references

Photon and photon reactions: elementary theoretical introduction

International Nuclear Information System (INIS)

Diu, B.

The electromagnetic field and associated quanta, the photons, are simply and briefly studied. The conventional electromagnetism laws are recalled. Fundamental concepts such as gauge invariance, the electromagnetic current conservation, and photon behavior against the internal symmetries of strong interactions are simply introduced. Results and notations are applied to analysis of reactions where photons intervene in initial or final states (photoproduction) within the limits of amplitude properties in the conventional space-time. The helicity and invariant amplitude formalisms are compared [fr

Modeling of the symmetry factor of electrochemical proton discharge via the Volmer reaction

DEFF Research Database (Denmark)

Björketun, Mårten E.; Tripkovic, Vladimir; Skúlason, Egill

2013-01-01

A scheme for evaluating symmetry factors of elementary electrode reactions using a density functional theory (DFT) based model of the electrochemical double layer is presented. As an illustration, the symmetry factor is determined for hydrogen adsorption via the electrochemical Volmer reaction...

Neutron-proton bremsstrahlung from intermediate energy heavy-ion reactions as a probe of the nuclear symmetry energy?

International Nuclear Information System (INIS)

Yong, G.-C.; Li Baoan; Chen Liewen

2008-01-01

Hard photons from neutron-proton bremsstrahlung in intermediate energy heavy-ion reactions are examined as a potential probe of the nuclear symmetry energy within a transport model. Effects of the symmetry energy on the yields and spectra of hard photons are found to be generally smaller than those due to the currently existing uncertainties of both the in-medium nucleon-nucleon cross sections and the photon production probability in the elementary process pn→pnγ. Very interestingly, nevertheless, the ratio of hard photon spectra R 1/2 (γ) from two reactions using isotopes of the same element is not only approximately independent of these uncertainties but also quite sensitive to the symmetry energy. For the head-on reactions of 132 Sn + 124 Sn and 112 Sn + 112 Sn at E beam /A=50 MeV, for example, the R 1/2 (γ) displays a rise up to 15% when the symmetry energy is reduced by about 20% at ρ=1.3ρ 0 which is the maximum density reached in these reactions

INFLUENCE OF THE ISOBUTENE METHANOL RATIO AND OF THE METHYL TERT-BUTYL ETHER CONTENT ON THE REACTION-RATE OF THE SYNTHESIS OF METHYL TERT-BUTYL ETHER

NARCIS (Netherlands)

PANNEMAN, HJ; BEENACKERS, AACM

1995-01-01

The forward reaction rate constant of the MtBE synthesis was determined for different reaction mixture compositions. The forward rate constant decreases continuously with increasing isobutene/methanol ratio, while an increase in reaction rate constant is observed with an increasing amount of MtBE in

Hybrid elementary flux analysis/nonparametric modeling: application for bioprocess control

Directory of Open Access Journals (Sweden)

Alves Paula M

2007-01-01

Full Text Available Abstract Background The progress in the "-omic" sciences has allowed a deeper knowledge on many biological systems with industrial interest. This knowledge is still rarely used for advanced bioprocess monitoring and control at the bioreactor level. In this work, a bioprocess control method is presented, which is designed on the basis of the metabolic network of the organism under consideration. The bioprocess dynamics are formulated using hybrid rigorous/data driven systems and its inherent structure is defined by the metabolism elementary modes. Results The metabolic network of the system under study is decomposed into elementary modes (EMs, which are the simplest paths able to operate coherently in steady-state. A reduced reaction mechanism in the form of simplified reactions connecting substrates with end-products is obtained. A dynamical hybrid system integrating material balance equations, EMs reactions stoichiometry and kinetics was formulated. EMs kinetics were defined as the product of two terms: a mechanistic/empirical known term and an unknown term that must be identified from data, in a process optimisation perspective. This approach allows the quantification of fluxes carried by individual elementary modes which is of great help to identify dominant pathways as a function of environmental conditions. The methodology was employed to analyse experimental data of recombinant Baby Hamster Kidney (BHK-21A cultures producing a recombinant fusion glycoprotein. The identified EMs kinetics demonstrated typical glucose and glutamine metabolic responses during cell growth and IgG1-IL2 synthesis. Finally, an online optimisation study was conducted in which the optimal feeding strategies of glucose and glutamine were calculated after re-estimation of model parameters at each sampling time. An improvement in the final product concentration was obtained as a result of this online optimisation. Conclusion The main contribution of this work is a

A theoretical study of the alkylation reaction of toluene with methanol catalyzed by acidic mordenite

NARCIS (Netherlands)

Vos, A.M.; Rozanska, X.; Schoonheydt, R.A.; Santen, van R.A.; Hutschka, F.; Hafner, J.

2001-01-01

A theoretical study of the alkylation reaction of toluene with methanol catalyzed by the acidic Mordenite (Si/Al = 23) is reported. Cluster DFT as well as periodical structure DFT calculations have been performed. Full reaction energy diagrams of the elementary reaction steps that lead to the

SENSMG: First-Order Sensitivities of Neutron Reaction Rates, Reaction-Rate Ratios, Leakage, k_eff, and α Using PARTISN

Energy Technology Data Exchange (ETDEWEB)

Favorite, Jeffrey A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-11-21

SENSMG is a tool for computing first-order sensitivities of neutron reaction rates, reaction-rate ratios, leakage, k_eff, and α using the PARTISN multigroup discrete-ordinates code. SENSMG computes sensitivities to all of the transport cross sections and data (total, fission, nu, chi, and all scattering moments), two edit cross sections (absorption and capture), and the density for every isotope and energy group. It also computes sensitivities to the mass density for every material and derivatives with respect to all interface locations. The tool can be used for one-dimensional spherical (r) and two-dimensional cylindrical (r-z) geometries. The tool can be used for fixed-source and eigenvalue problems. The tool implements Generalized Perturbation Theory (GPT) as discussed by Williams and Stacey. Section II of this report describes the theory behind adjoint-based sensitivities, gives the equations that SENSMG solves, and defines the sensitivities that are output. Section III describes the user interface, including the input file and command line options. Section IV describes the output. Section V gives some notes about the coding that may be of interest. Section VI discusses verification, which is ongoing. Section VII lists needs and ideas for future work. Appendix A lists all of the input files whose results are presented in Sec. VI.

Reaction of iodine oxidation by potassium permanganate in tributyl phosphate

International Nuclear Information System (INIS)

Khokhlov, M.L.; Legin, E.K.

1990-01-01

Stoichiometry was determined and kinetics of iodine oxidation by potassium permanganate in tributylphosphate was studied. Kinetic scheme, which agrees with stoichiometry and experimental kinetic equation of the reaction, is suggested. A mixture is the reaction product. It is ascertained that when the mixture is heated, thermal decomposition of iodate to iodide occurs without elementary iodine separation, which is catalyzed by polymanganate

Elementary Preservice Teachers' and Elementary Inservice Teachers' Knowledge of Mathematical Modeling

Science.gov (United States)

Schwerdtfeger, Sara

2017-01-01

This study examined the differences in knowledge of mathematical modeling between a group of elementary preservice teachers and a group of elementary inservice teachers. Mathematical modeling has recently come to the forefront of elementary mathematics classrooms because of the call to add mathematical modeling tasks in mathematics classes through…

Copy number ratios determined by two digital polymerase chain reaction systems in genetically modified grains

Science.gov (United States)

Pérez Urquiza, M.; Acatzi Silva, A. I.

2014-02-01

Three certified reference materials produced from powdered seeds to measure the copy number ratio sequences of p35S/hmgA in maize containing MON 810 event, p35S/Le1 in soybeans containing GTS 40-3-2 event and DREB1A/acc1 in wheat were produced according to the ISO Guides 34 and 35. In this paper, we report digital polymerase chain reaction (dPCR) protocols, performance parameters and results of copy number ratio content of genetically modified organisms (GMOs) in these materials using two new dPCR systems to detect and quantify molecular deoxyribonucleic acid: the BioMark® (Fluidigm) and the OpenArray® (Life Technologies) systems. These technologies were implemented at the National Institute of Metrology in Mexico (CENAM) and in the Reference Center for GMO Detection from the Ministry of Agriculture (CNRDOGM), respectively. The main advantage of this technique against the more-used quantitative polymerase chain reaction (qPCR) is that it generates an absolute number of target molecules in the sample, without reference to standards or an endogenous control, which is very useful when not much information is available for new developments or there are no standard reference materials in the market as in the wheat case presented, or when it was not possible to test the purity of seeds as in the maize case presented here. Both systems reported enhanced productivity, increased reliability and reduced instrument footprint. In this paper, the performance parameters and uncertainty of measurement obtained with both systems are presented and compared.

Low energy ion-molecule reaction dynamics and chemiionization kinetics: Progress report, February 1, 1985-January 31, 1988

International Nuclear Information System (INIS)

Farrar, J.M.

1988-01-01

The research program at Rochester is devoted to an understanding of the dynamics of elementary gas phase ionic reactions by using the molecular beam methods. We seek to elucidate pathways for energy disposal in elementary reactions, with the goal of using this information to understand the topology of the potential surfaces which govern the reaction, applying the results to ionic channels in combustion systems. We have made significant accomplishments in several distinct areas of research in crossed beam studies of ion-neutral reaction dynamics in the past three years. Our research has focused on the following topics and has resulted in 15 publications and submissions to major journals, with several additional manuscripts in preparation: dynamics of gas phase proton transfer reactions, gas phase carbon and methyl cation chemistry, reactive scattering from double minimum potentials, reactions of highly vibrationally excited ions: NH 3 + + D 2 , and electron and proton transfer reactions of anions. 9 refs

Rate constant computation on some elementary reactions of Hg during combustion

Energy Technology Data Exchange (ETDEWEB)

Wang, Qing; Yang, Bo-wen; Bai, Jing-ru [Northeast Dianli Univ., Jilin (China). Inst. of Energy and Power Engineering

2013-07-01

The geometry optimizations of reactants, products and transition states were made by the quantum chemistry MP2 method at the SDD basis function level for Hg, and 6-311++G(3df, 3pd) for others. The properties of stable minimums were validated by vibration frequencies analysis. Furthermore, the microcosmic chemical reaction mechanisms of reactions were investigated by ab initio calculations of quantum chemistry. On the basis of the geometry optimization, reaction rate constants within 298-2,000 K are calculated neither from experimental data nor by estimated, but directly from Quantum Chemistry software-Khimera.

Activation cross section and isomeric cross-section ratio for the (n,2n) reaction on {sup 132,134}Ba

Energy Technology Data Exchange (ETDEWEB)

Luo, Junhua [Hexi Univ., Zhangye (China). School of Physics and Electromechanical Engineering; Hexi Univ., Zhangye (China). Inst. of New Energy; Wu, Chunlei; Jiang, Li [Chinese Academy of Engineering Physics, Mianyang (China). Inst. of Nuclear Physics and Chemistry; Li, Suyuan [Hexi Univ., Zhangye (China). Inst. of New Energy

2017-07-01

Cross sections of the {sup 132}Ba(n,2n){sup 131m,g}Ba and {sup 134}Ba(n,2n){sup 133m,g}Ba reactions and their isomeric cross section ratios σ{sub m}/σ{sub g} have been measured by means of the activation technique at three neutron energies in the range 13-15 MeV. BaCO{sub 3} samples and Nb monitor foils were activated together to determine the reaction cross section and the incident neutron flux. The quasimonoenergetic neutrons beam were produced via the {sup 3}H(d,n){sup 4}He reaction at the Pd-300 Neutron Generator of the Chinese Academy of Engineering Physics (CAEP). The activities induced in the reaction products were measured using high-resolution γ ray spectroscopy. The pure cross section of the ground-state was derived from the absolute cross section of the metastable state and the residual nuclear decay analysis. Cross sections were also evaluated theoretically using the numerical nuclear model code, TALYS-1.8 with different level density options at neutron energies varying from the reaction threshold to 20 MeV. Results are discussed and compared with the corresponding literature.

From elementary flux modes to elementary flux vectors: Metabolic pathway analysis with arbitrary linear flux constraints

Science.gov (United States)

Klamt, Steffen; Gerstl, Matthias P.; Jungreuthmayer, Christian; Mahadevan, Radhakrishnan; Müller, Stefan

2017-01-01

Elementary flux modes (EFMs) emerged as a formal concept to describe metabolic pathways and have become an established tool for constraint-based modeling and metabolic network analysis. EFMs are characteristic (support-minimal) vectors of the flux cone that contains all feasible steady-state flux vectors of a given metabolic network. EFMs account for (homogeneous) linear constraints arising from reaction irreversibilities and the assumption of steady state; however, other (inhomogeneous) linear constraints, such as minimal and maximal reaction rates frequently used by other constraint-based techniques (such as flux balance analysis [FBA]), cannot be directly integrated. These additional constraints further restrict the space of feasible flux vectors and turn the flux cone into a general flux polyhedron in which the concept of EFMs is not directly applicable anymore. For this reason, there has been a conceptual gap between EFM-based (pathway) analysis methods and linear optimization (FBA) techniques, as they operate on different geometric objects. One approach to overcome these limitations was proposed ten years ago and is based on the concept of elementary flux vectors (EFVs). Only recently has the community started to recognize the potential of EFVs for metabolic network analysis. In fact, EFVs exactly represent the conceptual development required to generalize the idea of EFMs from flux cones to flux polyhedra. This work aims to present a concise theoretical and practical introduction to EFVs that is accessible to a broad audience. We highlight the close relationship between EFMs and EFVs and demonstrate that almost all applications of EFMs (in flux cones) are possible for EFVs (in flux polyhedra) as well. In fact, certain properties can only be studied with EFVs. Thus, we conclude that EFVs provide a powerful and unifying framework for constraint-based modeling of metabolic networks. PMID:28406903

Communications: Elementary oxygen electrode reactions in the aprotic Li-air battery

DEFF Research Database (Denmark)

Hummelshøj, Jens Strabo; Blomquist, Jakob; Datta, Soumendu

2010-01-01

We discuss the electrochemical reactions at the oxygen electrode of an aprotic Li-air battery. Using density functional theory to estimate the free energy of intermediates during the discharge and charge of the battery, we introduce a reaction free energy diagram and identify possible origins...

Supersonic molecular beam experiments on surface chemical reactions.

Science.gov (United States)

Okada, Michio

2014-10-01

The interaction of a molecule and a surface is important in various fields, and in particular in complex systems like biomaterials and their related chemistry. However, the detailed understanding of the elementary steps in the surface chemistry, for example, stereodynamics, is still insufficient even for simple model systems. In this Personal Account, I review our recent studies of chemical reactions on single-crystalline Cu and Si surfaces induced by hyperthermal oxygen molecular beams and by oriented molecular beams, respectively. Studies of oxide formation on Cu induced by hyperthermal molecular beams demonstrate a significant role of the translational energy of the incident molecules. The use of hyperthermal molecular beams enables us to open up new chemical reaction paths specific for the hyperthermal energy region, and to develop new methods for the fabrication of thin films. On the other hand, oriented molecular beams also demonstrate the possibility of understanding surface chemical reactions in detail by varying the orientation of the incident molecules. The steric effects found on Si surfaces hint at new ways of material fabrication on Si surfaces. Controlling the initial conditions of incoming molecules is a powerful tool for finely monitoring the elementary step of the surface chemical reactions and creating new materials on surfaces. Copyright © 2014 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Elementary Environmental Activities.

Science.gov (United States)

Larson, Robert J.

This guide presents suggestions for field trips, out-of-doors activities, material for centers, and individualized activities in the teaching of elementary school science and particularly environmental education at the elementary level. The guide includes a section on preparation and procedures for conducting field trips, including sample…

The Sandy Hook Elementary School shooting as tipping point: "This Time Is Different".

Science.gov (United States)

Shultz, James M; Muschert, Glenn W; Dingwall, Alison; Cohen, Alyssa M

2013-01-01

Among rampage shooting massacres, the Sandy Hook Elementary School shooting on December 14, 2012 galvanized public attention. In this Commentary we examine the features of this episode of gun violence that has sparked strong reactions and energized discourse that may ultimately lead toward constructive solutions to diminish high rates of firearm deaths and injuries in the United States.

Direct and Indirect Determinations of Elementary Rate Constants H + O2: Chain Branching; the Dehydration of tertiary-Butanol; the Retro Diels-Alder Reaction of Cyclohexene; the Dehydration of Isopropanol

Science.gov (United States)

Heyne, Joshua S.

Due to growing environmental concern over the continued use of fossil fuels, methods to limit emissions and partially replace fossil fuel use with renewable biofuels are of considerable interest. Developing chemical kinetic models for the chemistry that affects combustion properties is important to understanding how new fuels affect combustion energy conversion processes in transportation devices. This thesis reports the experimental study of several important reactions (the H + O2 branching reaction, the key decomposition reactions of tertiary-butanol, the dehydration reaction of isopropanol, and the retro Diels-Alder reaction of cyclohexene) and develops robust analysis methods to estimate the absolute uncertainties of specific elementary rate constants derived from the experimental data. In the study of the above reactions, both a direct and indirect rate constant determination technique with associated uncertainty estimation methodologies are developed. In the study of the decomposition reactions, a direct determination technique is applied to experimental data gathered in preparation of this thesis. In the case of the dehydration reaction of tertiary-butanol and the retro Diels-Alder reaction of cyclohexene, both of which are used as internal standards for relative rate studies (Herzler et al. 1997) and chemical thermometry (Rosado-Reyes et al. 2013) , analysis showed an ˜20 K difference in the reaction rate between the reported results and the previous recommendations. In light of these discrepancies, an uncertainty estimation of previous recommendations illuminated an uncertainty of at least 20 K for the dehydration reaction of tertiary-butanol and the retro Diels-Alder reaction of cyclohexene, thus resolving the discrepancies. The determination of the H + O2 branching reaction and decomposition reactions of isopropanol used an indirect determination technique. The uncertainty of the H + O2 branching reaction rate is shown to be underestimated by previous

Determination of Sperm Sex Ratio in Bovine Semen Using Multiplex Real-time Polymerase Chain Reaction

Directory of Open Access Journals (Sweden)

Trisadee Khamlor

2014-10-01

Full Text Available Gender selection is important in livestock industries; for example, female calves are required in the dairy industry. Sex-sorted semen is commonly used for the production of calves of the desired gender. However, assessment of the sex ratio of the sorted semen is tedious and expensive. In this study, a rapid, cost effective and reliable method for determining the sex ratio was developed using a multiplex real-time polymerase chain reaction (PCR assay. In this assay, the X and Y chromosome-specific markers, i.e., bovine proteolipid protein (PLP gene and sex-determining region Y (SRY were simultaneously quantified in a single tube. The multiplex real-time PCR assay was shown to have high amplification efficiencies (97% to 99% comparable to the separated-tube simplex real-time PCR assay. The results obtained from both assays were not significantly different (p>0.05. The multiplex assay was validated using reference DNA of known X ratio (10%, 50%, and 90% as templates. The measured %X in semen samples were the same within 95% confidence intervals as the expected values, i.e., >90% in X-sorted semen, <10% in Y-sorted semen and close to 50% in the unsorted semen. The multiplex real-time PCR assay as shown in this study can thus be used to assess purity of sex-sorted semen.

A taxonomy of integral reaction path analysis

Energy Technology Data Exchange (ETDEWEB)

Grcar, Joseph F.; Day, Marcus S.; Bell, John B.

2004-12-23

W. C. Gardiner observed that achieving understanding through combustion modeling is limited by the ability to recognize the implications of what has been computed and to draw conclusions about the elementary steps underlying the reaction mechanism. This difficulty can be overcome in part by making better use of reaction path analysis in the context of multidimensional flame simulations. Following a survey of current practice, an integral reaction flux is formulated in terms of conserved scalars that can be calculated in a fully automated way. Conditional analyses are then introduced, and a taxonomy for bidirectional path analysis is explored. Many examples illustrate the resulting path analysis and uncover some new results about nonpremixed methane-air laminar jets.

The influence of the "cage effect" on the mechanism of reversible bimolecular multistage chemical reactions in solutions.

Science.gov (United States)

Doktorov, Alexander B

2015-08-21

Manifestations of the "cage effect" at the encounters of reactants are theoretically treated by the example of multistage reactions in liquid solutions including bimolecular exchange reactions as elementary stages. It is shown that consistent consideration of quasi-stationary kinetics of multistage reactions (possible only in the framework of the encounter theory) for reactions proceeding near reactants contact can be made on the basis of the concepts of a "cage complex." Though mathematically such a consideration is more complicated, it is more clear from the standpoint of chemical notions. It is established that the presence of the "cage effect" leads to some important effects not inherent in reactions in gases or those in solutions proceeding in the kinetic regime, such as the appearance of new transition channels of reactant transformation that cannot be caused by elementary event of chemical conversion for the given mechanism of reaction. This results in that, for example, rate constant values of multistage reaction defined by standard kinetic equations of formal chemical kinetics from experimentally measured kinetics can differ essentially from real values of these constants.

On the mesonic-exchange currents in the photomesic reactions

International Nuclear Information System (INIS)

Lazard, C.; Maric, Z.; Zivanovic, D.

1979-02-01

The γd→π 0 d reaction is analysed in the framework of the relativistic many-body theory with mesonic degrees of freedom explicitly present. It is shown that the mesonic correlations can be grouped into transition operators containing vertices of some elementary reactions between photon, nucleons and pions. The wave function corrections due to meson exchange currents are included in the transition operators and the S-matrix is obtained with the non relativistic deuteron wave function

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.

The HNC/HCN ratio in star-forming regions

International Nuclear Information System (INIS)

Graninger, Dawn M.; Öberg, Karin I.; Herbst, Eric; Vasyunin, Anton I.

2014-01-01

HNC and HCN, typically used as dense gas tracers in molecular clouds, are a pair of isomers that have great potential as a temperature probe because of temperature dependent, isomer-specific formation and destruction pathways. Previous observations of the HNC/HCN abundance ratio show that the ratio decreases with increasing temperature, something that standard astrochemical models cannot reproduce. We have undertaken a detailed parameter study on which environmental characteristics and chemical reactions affect the HNC/HCN ratio and can thus contribute to the observed dependence. Using existing gas and gas-grain models updated with new reactions and reaction barriers, we find that in static models the H + HNC gas-phase reaction regulates the HNC/HCN ratio under all conditions, except for very early times. We quantitatively constrain the combinations of H abundance and H + HNC reaction barrier that can explain the observed HNC/HCN temperature dependence and discuss the implications in light of new quantum chemical calculations. In warm-up models, gas-grain chemistry contributes significantly to the predicted HNC/HCN ratio and understanding the dynamics of star formation is therefore key to model the HNC/HCN system.

Departmentalize Elementary Schools

Science.gov (United States)

Chan, Tak Cheung; Jarman, Delbert

2004-01-01

In elementary schools today, most students receive their education in a single classroom from one teacher who is responsible for teaching language arts, social studies, math, and science. The self-contained classroom organization is predicated on the assumption that an elementary school teacher is a Jack (or Jill)-of-all-trades who is equally…

Complex Reaction Kinetics in Chemistry: A Unified Picture Suggested by Mechanics in Physics

Directory of Open Access Journals (Sweden)

Elena Agliari

2018-01-01

Full Text Available Complex biochemical pathways can be reduced to chains of elementary reactions, which can be described in terms of chemical kinetics. Among the elementary reactions so far extensively investigated, we recall the Michaelis-Menten and the Hill positive-cooperative kinetics, which apply to molecular binding and are characterized by the absence and the presence, respectively, of cooperative interactions between binding sites. However, there is evidence of reactions displaying a more complex pattern: these follow the positive-cooperative scenario at small substrate concentration, yet negative-cooperative effects emerge as the substrate concentration is increased. Here, we analyze the formal analogy between the mathematical backbone of (classical reaction kinetics in Chemistry and that of (classical mechanics in Physics. We first show that standard cooperative kinetics can be framed in terms of classical mechanics, where the emerging phenomenology can be obtained by applying the principle of least action of classical mechanics. Further, since the saturation function plays in Chemistry the same role played by velocity in Physics, we show that a relativistic scaffold naturally accounts for the kinetics of the above-mentioned complex reactions. The proposed formalism yields to a unique, consistent picture for cooperative-like reactions and to a stronger mathematical control.

Negative ion molecule reactions of WF6: evidence for a pressure dependent branching ratio

International Nuclear Information System (INIS)

Viggiano, A.A.; Paulson, J.F.

1984-01-01

Rate coefficients have been measured in a selected ion flow tube (SIFT) for reactions of several negative ions with WF 6 . With the exception of SF - 5 , all the reactant ions studied having an electron detachment energy less than 3.36 eV reacted rapidly by charge exchange. SF - 5 transferred a fluoride ion producing WF - 7 . Ions with detachment energies greater than 3.36 eV associated rapidly with WF - 6 . Br - , with a detachment energy of 3.36 eV, reacted with WF 6 both by ion-neutral association and by charge exchange. The branching ratio for these two channels was found to depend on temperature and pressure. All these data indicate that the electron affinity of WF 6 is nearly equal to that of Br

Elementary particles

International Nuclear Information System (INIS)

Prasad, R.

1984-01-01

Two previous monographs report on investigations into the extent to which a unified field theory can satisfactorily describe physical reality. The first, Unified field Theory, showed that the paths within a non-Riemannian space are governed by eigenvalue equations. The second, Fundamental Constants, show that the field tensors satisfy sets of differential equations with solutions which represent the evolution of the fields along the paths of the space. The results from the first two monographs are used in this one to make progress on the theory of elementary particles. The five chapters are as follows - Quantum mechanics, gravitation and electromagnetism are aspects of the Unified theory; the fields inside the particle; the quadratic and linear theories; the calculation of the eigenvalues and elementary particles as stable configurations of interacting fields. It is shown that it is possible to construct an internal structure theory for elementary particles. The theory lies within the framework of Einstein's programme-to identify physical reality with a specified geometrical structure. (U.K.)

Comparative Study Between Ethylbenzene Disproportionation Reaction and its Ethylation Reaction with Ethanol over ZSM-5

KAUST Repository

Tukur, N. M.

2009-06-23

Ethylation of ethylbenzene with ethanol has been studied over ZSM-5 catalyst in a riser simulator that mimics the operation of a fluidized-bed reactor. The feed molar ratio of ethylbenzene:ethanol is 1:1. The study was carried out at 350, 400, 450, and 500°C for reaction times of 3, 5, 7, 10, 13, and 15 s. Comparisons are made between the results of the ethylbenzene ethylation reaction with that of ethylbenzene disproportionation reaction earlier reported. The effect of reaction conditions on ethylbenzene reactivity, p-diethylbenzene selectivity, total diethylbenzene (DEB) isomers selectivity, p-DEB-to-m-DEB ratio, benzene-to-DEB molar ratio, and benzene selectivity, are reported. Benzene selectivity is about 10 times more in the EB disproportion reaction as compared to its ethylation reaction with ethanol at 350°C. In addition, the results showed a p-DEB/m-DEB ratio for the EB ethylation reaction varying between 1.2-1.7, which is greater than the equilibrium values. Increase in temperature shifts the alkylation/dealkylation equilibrium towards dealkylation, thereby decreasing conversion and selectivity to DEB. © Springer Science+Business Media, LLC 2009.

The influence of the “cage effect” on the mechanism of reversible bimolecular multistage chemical reactions in solutions

International Nuclear Information System (INIS)

Doktorov, Alexander B.

2015-01-01

Manifestations of the “cage effect” at the encounters of reactants are theoretically treated by the example of multistage reactions in liquid solutions including bimolecular exchange reactions as elementary stages. It is shown that consistent consideration of quasi-stationary kinetics of multistage reactions (possible only in the framework of the encounter theory) for reactions proceeding near reactants contact can be made on the basis of the concepts of a “cage complex.” Though mathematically such a consideration is more complicated, it is more clear from the standpoint of chemical notions. It is established that the presence of the “cage effect” leads to some important effects not inherent in reactions in gases or those in solutions proceeding in the kinetic regime, such as the appearance of new transition channels of reactant transformation that cannot be caused by elementary event of chemical conversion for the given mechanism of reaction. This results in that, for example, rate constant values of multistage reaction defined by standard kinetic equations of formal chemical kinetics from experimentally measured kinetics can differ essentially from real values of these constants

The influence of the “cage effect” on the mechanism of reversible bimolecular multistage chemical reactions in solutions

Energy Technology Data Exchange (ETDEWEB)

Doktorov, Alexander B., E-mail: doktorov@kinetics.nsc.ru [Voevodsky Institute of Chemical Kinetics & Combustion, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia and Novosibirsk State University, Novosibirsk 630090 (Russian Federation)

2015-08-21

Manifestations of the “cage effect” at the encounters of reactants are theoretically treated by the example of multistage reactions in liquid solutions including bimolecular exchange reactions as elementary stages. It is shown that consistent consideration of quasi-stationary kinetics of multistage reactions (possible only in the framework of the encounter theory) for reactions proceeding near reactants contact can be made on the basis of the concepts of a “cage complex.” Though mathematically such a consideration is more complicated, it is more clear from the standpoint of chemical notions. It is established that the presence of the “cage effect” leads to some important effects not inherent in reactions in gases or those in solutions proceeding in the kinetic regime, such as the appearance of new transition channels of reactant transformation that cannot be caused by elementary event of chemical conversion for the given mechanism of reaction. This results in that, for example, rate constant values of multistage reaction defined by standard kinetic equations of formal chemical kinetics from experimentally measured kinetics can differ essentially from real values of these constants.

Inclusive Sigma- photoproduction on the neutron via the reaction gamma n (p) -→ K+ Sigma- (p)

International Nuclear Information System (INIS)

Jorn Langheinrich; Ana Lima; Barry Berman

2006-01-01

The analysis described here is part of a comprehensive survey of the elementary strangeness photoproduction cross sections on the nucleon. The six elementary strangeness reactions are γn → K 0 Λ and γp → K + Λ γn → K 0 Σ 0 and γp → K + Σ 0 γn → K + Σ - and γp → K 0 Σ| +

Measurement and analysis of the excitation function and isomeric cross section ratios for α-induced reaction on Ir, Au, Re and Ta nuclei

International Nuclear Information System (INIS)

Ismail, M.

1998-01-01

Excitation functions and a few isomeric cross section ratios for production of (1) 192 Au, 193 Au, 194 Au, 195 Au and 192 Ir nuclides in α-induced reactions on 191,193 Ir, (2) 197 Tl, 197m Hg, 198m.g Tl, 199 Tl and 200 Tl nuclides in α-induced reaction in 197 Au and (3) 183 Re and 184m.g Re nuclides in α-induced reaction in 181 Ta and 185 Re are obtained from the measurements of the residual activities by the conventional stacked-foils technique from threshold to 50 MeV. The excitation function and isomeric cross section ratios for nuclear reaction 181 Ta (α,n) 184m.g Re are compared with the theoretical calculation using the code Stapre which is based on exciton model for pre-equilibrium phase and Hauser-Feshbach formalism taking angular momentum and parity into account for the equilibrium phase of the nuclear reaction. All other experimental excitation functions are compared with the calculations considering equilibrium as well as pre-equilibrium reaction mechanism according to the geometry dependent hybrid (GDH) model and hybrid model of Blann using the code Alice/91. The high energy part of the excitation functions are dominated by pre-equilibrium reaction mechanism whereas the low energy parts are dominated by equilibrium evaporation with its characteristic peak. The GDH model provides a potentially better description of the physical process (i.e. a higher probability for peripheral collisions to undergo precompound decay than for central collisions) compared to hybrid model. However in the energy range of present measurement most of the excitation functions are fitted reasonably well by both GDH model and hybrid model with initial exciton number N 0 =4 (N n =2, N p =2, N h =0). Barring a few reactions we have found the overall agreement between theory and experiment is reasonably good taking the limitations of the theory into account. (author)

Long distance elementary measurement of the radiation dose ratio produced by neutron activation

International Nuclear Information System (INIS)

Zhou Changgeng; Lou Benchao; Wu Chunlei; Hu Yonghong; Li Yan

2009-04-01

The working principle and the structure and performances of a long distance controllable individual radiation dose ratio instrument are described. The radiation dose ratio produced by neutron activation is elementarily measured by using this instrument in the neutron generator hall with high neutron yield. When neutron yield arrives to 2 x 10 11 s -1 , the radiation dose ratio produced by neutron activation is 99.9 μSv/h in 1 h after the generator being stopped. The radiation dose ratio is reduced to 24.4 μSv/h in 39 h after the generator being stopped. When neutron yield is 3.2 x 10 10 s -1 , the radiation dose ratio produced by neutron activation is 21.9 μSv/h in 36 min, after the generator being stopped. The measurement results may provide reference for physical experimenters and neutron generator operators. (authors)

The influence of the "cage" effect on the mechanism of reversible bimolecular multistage chemical reactions proceeding from different sites in solutions.

Science.gov (United States)

Doktorov, Alexander B

2016-08-28

Manifestations of the "cage" effect at the encounters of reactants have been theoretically treated on the example of multistage reactions (including bimolecular exchange reactions as elementary stages) proceeding from different active sites in liquid solutions. It is shown that for reactions occurring near the contact of reactants, consistent consideration of quasi-stationary kinetics of such multistage reactions (possible in the framework of the encounter theory only) can be made on the basis of chemical concepts of the "cage complex," just as in the case of one-site model described in the literature. Exactly as in the one-site model, the presence of the "cage" effect gives rise to new channels of reactant transformation that cannot result from elementary event of chemical conversion for the given reaction mechanism. Besides, the multisite model demonstrates new (as compared to one-site model) features of multistage reaction course.

Development of linear free energy relationships for aqueous phase radical-involved chemical reactions.

Science.gov (United States)

Minakata, Daisuke; Mezyk, Stephen P; Jones, Jace W; Daws, Brittany R; Crittenden, John C

2014-12-02

Aqueous phase advanced oxidation processes (AOPs) produce hydroxyl radicals (HO•) which can completely oxidize electron rich organic compounds. The proper design and operation of AOPs require that we predict the formation and fate of the byproducts and their associated toxicity. Accordingly, there is a need to develop a first-principles kinetic model that can predict the dominant reaction pathways that potentially produce toxic byproducts. We have published some of our efforts on predicting the elementary reaction pathways and the HO• rate constants. Here we develop linear free energy relationships (LFERs) that predict the rate constants for aqueous phase radical reactions. The LFERs relate experimentally obtained kinetic rate constants to quantum mechanically calculated aqueous phase free energies of activation. The LFERs have been applied to 101 reactions, including (1) HO• addition to 15 aromatic compounds; (2) addition of molecular oxygen to 65 carbon-centered aliphatic and cyclohexadienyl radicals; (3) disproportionation of 10 peroxyl radicals, and (4) unimolecular decay of nine peroxyl radicals. The LFERs correlations predict the rate constants within a factor of 2 from the experimental values for HO• reactions and molecular oxygen addition, and a factor of 5 for peroxyl radical reactions. The LFERs and the elementary reaction pathways will enable us to predict the formation and initial fate of the byproducts in AOPs. Furthermore, our methodology can be applied to other environmental processes in which aqueous phase radical-involved reactions occur.

Elementary school students' perceptions of stuttering: A mixed model approach.

Science.gov (United States)

Panico, James; Healey, E Charles; Knopik, Jennifer

2015-09-01

Past research studies have focused on perceptions of stuttering by various age groups and only a few have examined how children react to a peer who stutters. All of these studies used a quantitative analysis but only one included a qualitative analysis of elementary school age children's responses to stuttering. The aim of this study was to further explore the perceptions of elementary school students toward a peer who stutters using both quantitative and qualitative analyses of three levels of stuttering. Participants included 88 elementary school children between 8 and 12 years of age. Each participant viewed one of four audiovisual samples of a peer producing fluent speech and mild, moderate, and severe simulated stuttering. Each participant then rated five Likert statements and answered three open-ended questions. Quantitative and qualitative results indicated that negative ratings and the percentage of negative comments increased as the frequency of stuttering increased. However, the children in this study indicated that they were comfortable listening to stuttering and would be comfortable making friends with the peer who stutters. The findings of this study together with past research in this area should help clinicians and their clients appreciate the range of social and emotional reactions peers have of a child who stutters. After reading this article, the reader will be able to: (a) discuss past research regarding children's perceptions of stuttering; (b) summarize the need to explore the perceptions of elementary-aged children toward a peer who stutters; (c) describe the major quantitative and qualitative findings of children's perceptions of stuttering; and (d) discuss the need for disseminating more information about stuttering to children and teachers. Copyright © 2015 Elsevier Inc. All rights reserved.

Error Ratio Analysis: Alternate Mathematics Assessment for General and Special Educators.

Science.gov (United States)

Miller, James H.; Carr, Sonya C.

1997-01-01

Eighty-seven elementary students in grades four, five, and six, were administered a 30-item multiplication instrument to assess performance in computation across grade levels. An interpretation of student performance using error ratio analysis is provided and the use of this method with groups of students for instructional decision making is…

Instructional support and implementation structure during elementary teachers' science education simulation use

Science.gov (United States)

Gonczi, Amanda L.; Chiu, Jennifer L.; Maeng, Jennifer L.; Bell, Randy L.

2016-07-01

This investigation sought to identify patterns in elementary science teachers' computer simulation use, particularly implementation structures and instructional supports commonly employed by teachers. Data included video-recorded science lessons of 96 elementary teachers who used computer simulations in one or more science lessons. Results indicated teachers used a one-to-one student-to-computer ratio most often either during class-wide individual computer use or during a rotating station structure. Worksheets, general support, and peer collaboration were the most common forms of instructional support. The least common instructional support forms included lesson pacing, initial play, and a closure discussion. Students' simulation use was supported in the fewest ways during a rotating station structure. Results suggest that simulation professional development with elementary teachers needs to explicitly focus on implementation structures and instructional support to enhance participants' pedagogical knowledge and improve instructional simulation use. In addition, research is needed to provide theoretical explanations for the observed patterns that should subsequently be addressed in supporting teachers' instructional simulation use during professional development or in teacher preparation programs.

PERCEPTIONS OF THE ELEMENTARY SCHOOL COUNSELOR.

Science.gov (United States)

BRADEN, BILLY; AND OTHERS

FACTORS ASSOCIATED WITH THE ROLE AND FUNCTION OF THE ELEMENTARY SCHOOL COUNSELOR AS THEY WERE PERCEIVED BY SELECTED ELEMENTARY SCHOOL COUNSELORS, ELEMENTARY SCHOOL PRINCIPALS, COUNSELOR EDUCATORS, AND STATE SUPERVISORS IN THE SOUTHERN ASSOCIATION FOR COUNSELOR EDUCATION AND SUPERVISION (SACES) REGION WERE IDENTIFIED. THREE INSTRUMENTS WERE…

High Zn/Al ratios enhance dehydrogenation vs hydrogen transfer reactions of Zn-ZSM-5 catalytic systems in methanol conversion to aromatics

DEFF Research Database (Denmark)

Pinilla-Herrero, Irene; Borfecchia, Elisa; Holzinger, Julian

2018-01-01

suggest that catalytic activity is associated with [Zn(H2O)n(OH)]+ species located in the exchange positions of the materials with little or no contribution of ZnO or metallic Zn. The effect of Zn/Al ratio on their catalytic performance in methanol conversion to aromatics has been investigated. In all...... cases, higher Zn content causes an increase in the yield of aromatics while keeping the production of alkanes low. For similar Zn contents, high densities of Al sites favour the hydrogen transfer reactions and alkane formation whereas in samples with low Al contents, and thus higher Zn/Al ratio...

Montecarlo calculation of the isomeric cross sections ratio for the reaction 237Np(n,2n)236Np

International Nuclear Information System (INIS)

Cleri, F.

1988-01-01

A Montecarlo calculation of the isomeric cross section ratio for the (n,2n) reaction on 237 Np has been carried out based on the Hauser-Feshbach formulation. A standard energy-dependent optical model potential was used, with zero deformation parameters and no spin-orbit coupling. Investigation was made about the role of the energy cut-off value, of the higher multipole (E2) transition, of the gamma-ray versus second neutron emission, of the value of the spin cutt-off parameter. The results give the correct qualitative energy dependence of the branching ratio, with the assumption that the 1 - level is the ground state. The spin cut-off value obtained indicates a less pronounced deviation of the nuclear moment of inertia from the rigid-body value, with respect to older evaluations for high-mass nuclei. (author)

A vacuum--generated inertia reaction force

International Nuclear Information System (INIS)

Rueda, Alfonso; Haisch, Bernard

2001-01-01

A clear and succinct covariant approach shows that, in principle, there must be a contribution to the inertia reaction force on an accelerated object by the surrounding vacuum electromagnetic field in which the object is embedded. No details of the vacuum to object electromagnetic interaction need to be specified other than the fact that the object is made of electromagnetically interacting particles. Some interesting consequences of this feature are discussed. This analysis strongly supports the concept that inertia is indeed an opposition of the vacuum fields to any attempt to change the uniform state of motion of material bodies. This also definitely shows that inertia should be viewed as extrinsic to mass and that causing agents and/or mechanisms responsible for the inertia reaction force are neither intrinsic to the notion of mass nor to the entities responsible for the existence of mass in elementary particles (as, e.g., the Higgs field). In other words the mechanism that produces the inertia-reaction-force requires an explicit explanation. This explicit explanation is that inertia is an opposition of the vacuum fields to the accelerated motion of any material entities, i.e., of entities that possess mass. It is briefly commented why the existence of a Higgs field responsible for the generation of mass in elementary particles does not contradict the view presented here. It is also briefly discussed why a strict version of Mach's Principle does really contradict this view, though a broad sense version of Mach's Principle may be in agreement

Preservice Elementary Teachers' Adaptation of Science Curriculum Materials for Inquiry-Based Elementary Science

Science.gov (United States)

Forbes, Cory T.

2011-01-01

Curriculum materials are important resources with which teachers make pedagogical decisions about the design of science learning environments. To become well-started beginning elementary teachers capable of engaging their students in inquiry-based science, preservice elementary teachers need to learn to use science curriculum materials…

Elementary Atom Interaction with Matter

OpenAIRE

Mrowczynski, Stanislaw

1998-01-01

The calculations of the elementary atom (the Coulomb bound state of elementary particles) interaction with the atom of matter, which are performed in the Born approximation, are reviewed. We first discuss the nonrelativistic approach and then its relativistic generalization. The cross section of the elementary atom excitation and ionization as well as the total cross section are considered. A specific selection rule, which applies for the atom formed as positronium by particle-antiparticle pa...

34 CFR 300.13 - Elementary school.

Science.gov (United States)

2010-07-01

... 34 Education 2 2010-07-01 2010-07-01 false Elementary school. 300.13 Section 300.13 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND... DISABILITIES General Definitions Used in This Part § 300.13 Elementary school. Elementary school means a...

Characterizing gamma fields using isomeric activation ratios

Science.gov (United States)

Venkataraman, Ramkumar; Fleming, Ronald F.

1994-12-01

Isomeric activities were induced in indium by gamma irradiation in three different gamma fields, through the reactions 115In(γ, γ') 115mIn and 113In(γ, γ') 113mIn. The irradiation fields were (i) the 15 kCi 60Co source available in the University, (ii) the spent fuel gamma irradiator in the pool of the University's Ford Nuclear Reactor (FNR) and (iii) south face of the core of the FNR during routine shut downs. Isomeric activation ratios can serve to characterize gamma fields, provided the response functions of the two (γ, γ') reactions sample different energy regimes of the gamma spectrum present in the irradiation fields. The response of an isomeric activation detector, in turn, depends on the number of activation energy levels of the nuclide and the probabilities with which the activation levels de-populate to the isomeric level. The reaction rate ratio RIn115m/ RIn113m was measured in the three gamma fields. The measured ratios were (i) 1.210 ± 0.011 in the 60Co source, (ii) 1.314 ± 0.060 in the spent fuel gamma irradiator and (iii) 1.298 ± 0.039 in a location alongside the FNR core during routine shut downs. The measured reaction rate ratios are not only close to each other, but close to unity as well. This indicates that the excitation functions for the reactions 115In(γ, γ') 115mIn and 113In(γ, γ') 113mIn have similar shapes and that for the nuclides 115In and 113In, the number of activation energy levels and the probabilities with which they populate the isomeric levels are very similar to each other. Thus, the ratio RIn115m/ RIn113m will not yield any information regarding the shape of gamma spectrum in the field of measurement. However by choosing (γ, γ') reactions with different shapes for the excitation functions one can measure a set of isomeric activation ratios that characterize a given gamma field.

Elementary particles, dark matter candidate and new extended standard model

Science.gov (United States)

Hwang, Jaekwang

2017-01-01

Elementary particle decays and reactions are discussed in terms of the three-dimensional quantized space model beyond the standard model. Three generations of the leptons and quarks correspond to the lepton charges. Three heavy leptons and three heavy quarks are introduced. And the bastons (new particles) are proposed as the possible candidate of the dark matters. Dark matter force, weak force and strong force are explained consistently. Possible rest masses of the new particles are, tentatively, proposed for the experimental searches. For more details, see the conference paper at https://www.researchgate.net/publication/308723916.

Pulse radiolysis studies of fast reactions in molecular systems. Progress report, November 1976--October 1977

International Nuclear Information System (INIS)

Dorfman, L.M.

1977-01-01

Results from research in the following two areas are given: formation, properties, and reactivity of molecular ionic species in irradiated liquid systems; and pulse radiolysis of elementary reactions in protein function

Elementary kinetic modelling applied to solid oxide fuel cell pattern anodes and a direct flame fuel cell system

Energy Technology Data Exchange (ETDEWEB)

Vogler, Marcel

2009-05-27

In the course of this thesis a model for the prediction of polarisation characteristics of solid oxide fuel cells (SOFC) was developed. The model is based on an elementary kinetic description of electrochemical reactions and the fundamental conservation principles of mass and energy. The model allows to predict the current-voltage relation of an SOFC and offers ideal possibilities for model validation. The aim of this thesis is the identification of rate-limiting processes and the determination of the elementary pathway during charge transfer. The numerical simulation of experiments with model anodes allowed to identify a hydrogen transfer to be the most probable charge-transfer reaction and revealed the influence of diffusive transport. Applying the hydrogen oxidation kinetics to the direct flame fuel cell system (DFFC) showed that electrochemical oxidation of CO is possible based on the same mechanism. Based on the quantification of loss processes in the DFFC system, improvements on cell design, predicting 80% increase of efficiency, were proposed. (orig.)

Do Elementary Particles Have an Objective Existence?

OpenAIRE

Nissenson, Bilha

2007-01-01

The formulation of quantum theory does not comply with the notion of objective existence of elementary particles. Objective existence independent of observation implies the distinguishability of elementary particles. In other words: If elementary particles have an objective existence independent of observations, then they are distinguishable. Or if elementary particles are indistinguishable then matter cannot have existence independent of our observation. This paper presents a simple deductio...

Cross-Section Measurement of the 169Tm(n,3n)167Tm Reaction and Constraining the Branching Ratio of 167Tm

Science.gov (United States)

Champine, Brian; Gooden, Matthew; Thomas, Keenan; Krishichayan, F.; Norman, Eric; Scielzo, Nick; Tonchev, Anton; Tornow, Werner

2015-10-01

The cross section of the 169Tm(n,3n)167Tm reaction has been measured from 17.5 to 21.5 MeV using activation technique. This energy region was chosen to resolve the two different trends of the previous (n,3n) cross section measurements on 169Tm. In addition, the branching ratio of the 207.8 keV γ-ray line stemming from electron capture of 167Tm was measured to be 0.419(16). The result of these measurements provide more accurate diagnostic estimation of the so called reaction-in-flight neutrons produced via the internal confinement fusion plasma in deuterium-tritium capsules at the National Ignition Facility.

Golden ratio beauty as scientific function

Directory of Open Access Journals (Sweden)

Scott A. Olsen

2018-01-01

Full Text Available Normally when one is considering the golden ratio in the history of ideas, one is often looking at it as an aesthetic principle – usually associated with Greek art, sculpture and mathematics. However, in recent years the prevalence of the golden ratio within a broad range of scientific disciplines has brought its role in the perfection of science to the forefront. I would like to collapse these two areas by proposing a somewhat novel way of looking at the aesthetics of the golden ratio: its pervasive expression in scientific form and function is the basis of the aesthetics in the world. Therefore, science contains the same mathematical beauty as found in artistic expression. The golden ratio guides the Chaos Border of Kolmogorov, Arnold, and Moser (KAM theorem and it can be found hidden in all elementary particles, and even in the proportions of dark matter and energy relative to visible matter and energy. It is evident in the structure and growth functions of plants and animals and it can be found in the physiological functions of humans. It now appears that without the golden ratio, we would not have the form or function of the proton, cell, athlete, horse, species, planet, solar system or galaxy.

Notes on elementary particle physics

CERN Document Server

Muirhead, William Hugh

1972-01-01

Notes of Elementary Particle Physics is a seven-chapter text that conveys the ideas on the state of elementary particle physics. This book emerged from an introductory course of 30 lectures on the subject given to first-year graduate students at the University of Liverpool. The opening chapter deals with pertinent terminologies in elementary particle physics. The succeeding three chapters cover the concepts of transition amplitudes, probabilities, relativistic wave equations and fields, and the interaction amplitude. The discussion then shifts to tests of electromagnetic interactions, particul

Behavioral Dysphonia and Depression in Elementary School Teachers.

Science.gov (United States)

Marques da Rocha, Luise; Behlau, Mara; Dias de Mattos Souza, Luciano

2015-11-01

To verify the relationship between behavioral dysphonia and current depressive episodes in municipal elementary school teachers. We hypothesize that teachers with behavioral dysphonia will be more susceptible to psychiatric disorders. Cross-sectional study, quantitative, conducted across municipal schools in both rural and urban regions of Pelotas. Five-hundred seventy-five teachers from urban and rural areas of the same Brazilian state were included. The full version of the Voice Handicap Index validated into Brazilian Portuguese was used to determine the presence of behavioral dysphonia. A profile of vocal behaviors was also used to quantify the number of phonotraumatic events. In addition, the Mini-International Neuropsychiatric Interview was used to determine current episodes of depression. Data were analyzed via correlative studies using chi-square and Poisson regression analyses. Across all teachers, the prevalence of dysphonia was 33.9% and 55% reported that they had already taken a leave because of their voice. Those teachers with a current depressive episode had a higher rate of dysphonia compared with those without depression (prevalence ratio [PR] 1.66; P Teachers who presented with a risk of serious vocal problems had a prevalence ratio of 2.58, indicating a greater proportion of dysphonia, whereas teachers classified as champions of abuse were five times more likely compared with those teachers with behaved or candidates for voice problems. There is an association between behavioral dysphonia and current depressive episodes in elementary school teachers. Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Spatiotemporal Patterns in a Ratio-Dependent Food Chain Model with Reaction-Diffusion

Directory of Open Access Journals (Sweden)

Lei Zhang

2014-01-01

Full Text Available Predator-prey models describe biological phenomena of pursuit-evasion interaction. And this interaction exists widely in the world for the necessary energy supplement of species. In this paper, we have investigated a ratio-dependent spatially extended food chain model. Based on the bifurcation analysis (Hopf and Turing, we give the spatial pattern formation via numerical simulation, that is, the evolution process of the system near the coexistence equilibrium point (u2*,v2*,w2*, and find that the model dynamics exhibits complex pattern replication. For fixed parameters, on increasing the control parameter c1, the sequence “holes → holes-stripe mixtures → stripes → spots-stripe mixtures → spots” pattern is observed. And in the case of pure Hopf instability, the model exhibits chaotic wave pattern replication. Furthermore, we consider the pattern formation in the case of which the top predator is extinct, that is, the evolution process of the system near the equilibrium point (u1*,v1*,0, and find that the model dynamics exhibits stripes-spots pattern replication. Our results show that reaction-diffusion model is an appropriate tool for investigating fundamental mechanism of complex spatiotemporal dynamics. It will be useful for studying the dynamic complexity of ecosystems.

Experimental and theoretical studies of the O(3P) + C2H4 reaction dynamics: Collision energy dependence of branching ratios and extent of intersystem crossing

Science.gov (United States)

Fu, Bina; Han, Yong-Chang; Bowman, Joel M.; Leonori, Francesca; Balucani, Nadia; Angelucci, Luca; Occhiogrosso, Angela; Petrucci, Raffaele; Casavecchia, Piergiorgio

2012-12-01

The reaction of O(3P) with C2H4, of importance in combustion and atmospheric chemistry, stands out as paradigm reaction involving not only the indicated triplet state potential energy surface (PES) but also an interleaved singlet PES that is coupled to the triplet surface. This reaction poses great challenges for theory and experiment, owing to the ruggedness and high dimensionality of these potentials, as well as the long lifetimes of the collision complexes. Crossed molecular beam (CMB) scattering experiments with soft electron ionization detection are used to disentangle the dynamics of this polyatomic multichannel reaction at a collision energy Ec of 8.4 kcal/mol. Five different primary products have been identified and characterized, which correspond to the five exothermic competing channels leading to H + CH2CHO, H + CH3CO, CH3 + HCO, CH2 + H2CO, and H2 + CH2CO. These experiments extend our previous CMB work at higher collision energy (Ec ˜ 13 kcal/mol) and when the results are combined with the literature branching ratios from kinetics experiments at room temperature (Ec ˜ 1 kcal/mol), permit to explore the variation of the branching ratios over a wide range of collision energies. In a synergistic fashion, full-dimensional, QCT surface hopping calculations of the O(3P) + C2H4 reaction using ab initio PESs for the singlet and triplet states and their coupling, are reported at collision energies corresponding to the CMB and the kinetics ones. Both theory and experiment find almost an equal contribution from the triplet and singlet surfaces to the reaction, as seen from the collision energy dependence of branching ratios of product channels and extent of intersystem crossing (ISC). Further detailed comparisons at the level of angular distributions and translational energy distributions are made between theory and experiment for the three primary radical channel products, H + CH2CHO, CH3 + HCO, and CH2 + H2CO. The very good agreement between theory and

Reactions of nitrate salts with ammonia in supercritical water

International Nuclear Information System (INIS)

Dell'Orco, P.C.; Gloyna, E.F.; Buelow, S.J.

1997-01-01

Reactions involving nitrate salts and ammonia were investigated in supercritical water at temperatures from 450 to 530 C and pressures near 300 bar. Reaction products included nitrite, nitrogen gas, and nitrous oxide. Observed reaction rates and product distributions provided evidence for a free-radical reaction mechanism with NO 2 , NO, and NH 2 · as the primary reactive species at supercritical conditions. In the proposed elementary mechanism, the rate-limiting reaction step was determined to be the hydrolysis of MNO 3 species, which resulted in the formation of nitric acid and subsequently NO 2 . A simple second-order reaction model was used to represent the data. In developing an empirical kinetic model, nitrate and nitrate were lumped as an NO x - reactant. Empirical kinetic parameters were developed for four MNO x /NH 3 reacting systems, assuming first orders in both NH 3 and NO x - . Observed MNO x /NH 3 reaction rates and mechanisms suggest immediately a practical significance of these reactions for nitrogen control strategies in supercritical water oxidation processes

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

Bimodality: A Sign of Critical Behavior in Nuclear Reactions

International Nuclear Information System (INIS)

Le Fevre, A.; Aichelin, J.

2008-01-01

The recently discovered coexistence of multifragmentation and residue production for the same total transverse energy of light charged particles, which has been dubbed bimodality like it has been introduced in the framework of equilibrium thermodynamics, can be well reproduced in numerical simulations of heavy ion reactions. A detailed analysis shows that fluctuations (introduced by elementary nucleon-nucleon collisions) determine which of the exit states is realized. Thus, we can identify bifurcation in heavy ion reactions as a critical phenomenon. Also the scaling of the coexistence region with beam energy is well reproduced in these results from the quantum molecular dynamics simulation program

Bullying, psychosocial adjustment, and academic performance in elementary school.

Science.gov (United States)

Glew, Gwen M; Fan, Ming-Yu; Katon, Wayne; Rivara, Frederick P; Kernic, Mary A

2005-11-01

Over the past decade, concerns about bullying and its role in school violence, depression, and health concerns have grown. However, no large studies in the United States have examined the prevalence of bullying during elementary school or its association with objective measures of school attendance and achievement. To determine the prevalence of bullying during elementary school and its association with school attendance, academic achievement, disciplinary actions, and self-reported feelings of sadness, safety, and belonging. Cross-sectional study using 2001-2002 school data. Urban, West Coast public school district. Three thousand five hundred thirty (91.4%) third, fourth, and fifth grade students. Self-reported involvement in bullying. Twenty-two percent of children surveyed were involved in bullying either as a victim, bully, or both. Victims and bully-victims were more likely to have low achievement than bystanders (odds ratios [ORs], 0.8 [95% confidence interval (CI), 0.7-0.9] and 0.8 [95% CI, 0.6-1.0], respectively). All 3 bullying-involved groups were significantly more likely than bystanders to feel unsafe at school (victims, OR, 2.1 [95% CI, 1.1-4.2]; bullies, OR, 2.5 [95% CI, 1.5-4.1]; bully-victims, OR, 5.0 [95% CI, 1.9-13.6]). Victims and bully-victims were more likely to report feeling that they don't belong at school (ORs, 4.1 [95% CI, 2.6-6.5] and 3.1 [95% CI, 1.3-7.2], respectively). Bullies and victims were more likely than bystanders to feel sad most days (ORs 1.5 [95% CI, 1.2-1.9] and 1.8 [95% CI, 1.2-2.8], respectively). Bullies and bully-victims were more likely to be male (ORs, 1.5 [95% CI, 1.2-1.9] and 3.0 [95% CI, 1.3-7.0], respectively). The prevalence of frequent bullying among elementary school children is substantial. Associations between bullying involvement and school problems indicate this is a serious issue for elementary schools. The research presented herein demonstrates the need for evidence-based antibullying curricula in the

SurfKin: an ab initio kinetic code for modeling surface reactions.

Science.gov (United States)

Le, Thong Nguyen-Minh; Liu, Bin; Huynh, Lam K

2014-10-05

In this article, we describe a C/C++ program called SurfKin (Surface Kinetics) to construct microkinetic mechanisms for modeling gas-surface reactions. Thermodynamic properties of reaction species are estimated based on density functional theory calculations and statistical mechanics. Rate constants for elementary steps (including adsorption, desorption, and chemical reactions on surfaces) are calculated using the classical collision theory and transition state theory. Methane decomposition and water-gas shift reaction on Ni(111) surface were chosen as test cases to validate the code implementations. The good agreement with literature data suggests this is a powerful tool to facilitate the analysis of complex reactions on surfaces, and thus it helps to effectively construct detailed microkinetic mechanisms for such surface reactions. SurfKin also opens a possibility for designing nanoscale model catalysts. Copyright © 2014 Wiley Periodicals, Inc.

Centrality in Hadron-Carbon, Hadron-Lead, and Lead-Lead Reactions at 158 GeV/c

International Nuclear Information System (INIS)

Rybicki, A.

2006-08-01

A study of centrality in p + C, π + C, p + Pb, π + Pb, and Pb + Pb reactions is made. The analysis is performed by means of a simple geometrical model. The mean number of elementary collisions, , is estimated in minimum bias p + C reactions. For the specific case of the carbon nucleus, estimates on appear to depend strongly on assumed nuclear densities. Most realistic of the presented assumptions result in a value of 1.71 ± 0.05. Additional quantities, like predictions for the total inelastic cross-section in p + C reactions, or the number of participants in minimum bias C + C collisions, are given. The analysis is subsequently extended to minimum bias π + C, π + Pb, and p + Pb reactions. Estimates are given for the mean number of elementary collisions as well as for the contribution of single collisions P(1). A comparison with experimental data is made. Finally, the impact parameter dependence of p + Pb and Pb + Pb collisions is discussed. In view of future studies, various aspects of the analysis are discussed in detail; a bibliography of used references is included. (author)

Molecular Beam Studies of Hot Atom Chemical Reactions: Reactive Scattering of Energetic Deuterium Atoms

Science.gov (United States)

Continetti, R. E.; Balko, B. A.; Lee, Y. T.

1989-02-01

A brief review of the application of the crossed molecular beams technique to the study of hot atom chemical reactions in the last twenty years is given. Specific emphasis is placed on recent advances in the use of photolytically produced energetic deuterium atoms in the study of the fundamental elementary reactions D + H{sub 2} -> DH + H and the substitution reaction D + C{sub 2}H{sub 2} -> C{sub 2}HD + H. Recent advances in uv laser and pulsed molecular beam techniques have made the detailed study of hydrogen atom reactions under single collision conditions possible.

Molecular beam studies of hot atom chemical reactions: Reactive scattering of energetic deuterium atoms

International Nuclear Information System (INIS)

Continetti, R.E.; Balko, B.A.; Lee, Y.T.

1989-02-01

A brief review of the application of the crossed molecular beams technique to the study of hot atom chemical reactions in the last twenty years is given. Specific emphasis is placed on recent advances in the use of photolytically produced energetic deuterium atoms in the study of the fundamental elementary reactions D + H 2 /minus/> DH + H and the substitution reaction D + C 2 H 2 /minus/> C 2 HD + H. Recent advances in uv laser and pulsed molecular beam techniques have made the detailed study of hydrogen atom reactions under single collision conditions possible. 18 refs., 9 figs

Elementary classical hydrodynamics

CERN Document Server

Chirgwin, B H; Langford, W J; Maxwell, E A; Plumpton, C

1967-01-01

Elementary Classical Hydrodynamics deals with the fundamental principles of elementary classical hydrodynamics, with emphasis on the mechanics of inviscid fluids. Topics covered by this book include direct use of the equations of hydrodynamics, potential flows, two-dimensional fluid motion, waves in liquids, and compressible flows. Some general theorems such as Bernoulli's equation are also considered. This book is comprised of six chapters and begins by introducing the reader to the fundamental principles of fluid hydrodynamics, with emphasis on ways of studying the motion of a fluid. Basic c

Elementary number theory

CERN Document Server

Dudley, Underwood

2008-01-01

Ideal for a first course in number theory, this lively, engaging text requires only a familiarity with elementary algebra and the properties of real numbers. Author Underwood Dudley, who has written a series of popular mathematics books, maintains that the best way to learn mathematics is by solving problems. In keeping with this philosophy, the text includes nearly 1,000 exercises and problems-some computational and some classical, many original, and some with complete solutions. The opening chapters offer sound explanations of the basics of elementary number theory and develop the fundamenta

Production cross sections and isomeric ratios for sup(110m)In/sup(110g)In formed in Cd (d,xn) reactions

International Nuclear Information System (INIS)

Herreros Usher, Oscar; Maceiras de Jefimowicz, Elena; De la Vega Vedoya, Mario; Jorge Nassiff, Sonia

1980-01-01

Excitation functions and isomeric cross sections ratios have been measured for the 110 Cd (d,2n) and 111 Cd (d,3n) reactions in which the isomeric pair sup(110m)In/sup(110g)In is produced. Activation method was employed and the irradiations were performed at the synchrocyclotron of the Comision Nacional de Energia Atomica, Argentina, with an incident energy of 27.MeV. (author) [es

Optimization and application of ICPMS with dynamic reaction cell for precise determination of 44Ca/40Ca isotope ratios.

Science.gov (United States)

Boulyga, Sergei F; Klötzli, Urs; Stingeder, Gerhard; Prohaska, Thomas

2007-10-15

An inductively coupled plasma mass spectrometer with dynamic reaction cell (ICP-DRC-MS) was optimized for determining (44)Ca/(40)Ca isotope ratios in aqueous solutions with respect to (i) repeatability, (ii) robustness, and (iii) stability. Ammonia as reaction gas allowed both the removal of (40)Ar+ interference on (40)Ca+ and collisional damping of ion density fluctuations of an ion beam extracted from an ICP. The effect of laboratory conditions as well as ICP-DRC-MS parameters such a nebulizer gas flow rate, rf power, lens potential, dwell time, or DRC parameters on precision and mass bias was studied. Precision (calculated using the "unbiased" or "n - 1" method) of a single isotope ratio measurement of a 60 ng g(-1) calcium solution (analysis time of 6 min) is routinely achievable in the range of 0.03-0.05%, which corresponded to the standard error of the mean value (n = 6) of 0.012-0.020%. These experimentally observed RSDs were close to theoretical precision values given by counting statistics. Accuracy of measured isotope ratios was assessed by comparative measurements of the same samples by ICP-DRC-MS and thermal ionization mass spectrometry (TIMS) by using isotope dilution with a (43)Ca-(48)Ca double spike. The analysis time in both cases was 1 h per analysis (10 blocks, each 6 min). The delta(44)Ca values measured by TIMS and ICP-DRC-MS with double-spike calibration in two samples (Ca ICP standard solution and digested NIST 1486 bone meal) coincided within the obtained precision. Although the applied isotope dilution with (43)Ca-(48)Ca double-spike compensates for time-dependent deviations of mass bias and allows achieving accurate results, this approach makes it necessary to measure an additional isotope pair, reducing the overall analysis time per isotope or increasing the total analysis time. Further development of external calibration by using a bracketing method would allow a wider use of ICP-DRC-MS for routine calcium isotopic measurements, but it

Reaction Mechanism Generator: Automatic construction of chemical kinetic mechanisms

Science.gov (United States)

Gao, Connie W.; Allen, Joshua W.; Green, William H.; West, Richard H.

2016-06-01

Reaction Mechanism Generator (RMG) constructs kinetic models composed of elementary chemical reaction steps using a general understanding of how molecules react. Species thermochemistry is estimated through Benson group additivity and reaction rate coefficients are estimated using a database of known rate rules and reaction templates. At its core, RMG relies on two fundamental data structures: graphs and trees. Graphs are used to represent chemical structures, and trees are used to represent thermodynamic and kinetic data. Models are generated using a rate-based algorithm which excludes species from the model based on reaction fluxes. RMG can generate reaction mechanisms for species involving carbon, hydrogen, oxygen, sulfur, and nitrogen. It also has capabilities for estimating transport and solvation properties, and it automatically computes pressure-dependent rate coefficients and identifies chemically-activated reaction paths. RMG is an object-oriented program written in Python, which provides a stable, robust programming architecture for developing an extensible and modular code base with a large suite of unit tests. Computationally intensive functions are cythonized for speed improvements.

Crowdfunding for Elementary Science Educators

Science.gov (United States)

Reese, Jessica; Miller, Kurtz

2017-01-01

The inadequate funding of science education in many school districts, particularly in underserved areas, is preventing elementary science educators from realizing the full potential of the "Next Generation Science Standards" ("NGSS"). Yet many elementary science teachers may be unaware that millions of dollars per year are…

Kaon production and kaon to pion ratio in Au+Au collisions at root(NN)-N-s=130 GeV

Czech Academy of Sciences Publication Activity Database

Adler, C.; Ahammed, Z.; Angelis, A. L. S.; Kugler, Andrej; Šumbera, Michal; Zborovský, Imrich

2004-01-01

Roč. 595, - (2004), s. 143-150 ISSN 0370-2693 R&D Projects: GA AV ČR KSK1048102 Keywords : heavy-ion collisions * plus Au reactions Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.619, year: 2004

Measurements of differential cross-section ratios for single-nucleon transfer reaction pairs near A=25

Energy Technology Data Exchange (ETDEWEB)

Howard, A J; Moise, T S [Trinity Coll., Hartford, CT (USA). Dept. of Physics; Champagne, A E [Princeton Univ., NJ (USA). Dept. of Physics; Magnus, P V; Smith, M S [Yale Univ., New Haven, CT (USA). Wright Nuclear Structure Lab.

1991-06-10

Differential cross sections for the (d,p), ({sup 3}He,d), ({alpha},t) and ({alpha},{sup 3}He) reactions involving seventy-one residual states in {sup 23}Na, {sup 25}Mg, {sup 25}Al, and {sup 27}Al have been measured at a forward angle with incident energies of 17.5, 20.2, and 34.8 MeV, respectively. The ratio of cross-section pairs involving formation of the same residual state is determined for forty-five cases where both the angular momentum transfer and single-particle spectroscopic strength have been previously established. These are compared to values calculated with conventional distorted-wave Born approximation analysis, and the utility of this technique for identifying some levels which are possible s- or p-wave resonances is demonstrated and discussed for states in the vicinity of proton thresholds. An application is made involving proton threshold states in {sup 27}Al. (orig.).

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}.

Peer Assessment of Elementary Science Teaching Skills

Science.gov (United States)

Kilic, Gulsen Bagci; Cakan, Mehtap

2007-01-01

In this study, peer assessment was applied in assessing elementary science teaching skills. Preservice teachers taught a science topic as a team to their peers in an elementary science methods course. The peers participating in the science lesson assessed teacher-groups' elementary science teaching skills on an assessment form provided by the…

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.

Interesterification reaction activity, fatty acid composition and selectivity ratio of soybean oil

Directory of Open Access Journals (Sweden)

El-Shattory, Y.

1998-12-01

Full Text Available The interesterification reaction was carried out by adding oleic acid to soybean oil by ratio 1:2 w/w under different conditions of temperature, stirring and catalyst percentages. Assessment of the interesterification of oils was reported by determination of saponification value, iodine value and fatty acids composition. This study showed that linolenic acid which is responsible for flavour instability of soybean oil and consider as primary factor contributing to deterioration of this oil could be reduced to less than or equals 3%.

Se han llevado a cabo reacciones de interesterificación mediante la adición de ácido oleico a aceite de soja en la relación 1:2 w/w bajo diferentes condiciones de temperatura, agitación y porcentaje de catalizador. La evaluación de la interesterificación de los aceites se realizó por determinación del índice de saponificación, el índice de iodo y la composición en ácidos grasos. Este estudio mostró que el ácido linolénico, que es responsable de la inestabilidad del flavor del aceite de soja y considerado como factor primario que contribuye a la deterioración de este aceite, podría ser reducido a cantidades menores o iguales al 3%.

Multiscale Informatics for Low-Temperature Propane Oxidation: Further Complexities in Studies of Complex Reactions

Energy Technology Data Exchange (ETDEWEB)

Burke, Michael P.; Goldsmith, C. Franklin; Klippenstein, Stephen J.; Welz, Oliver; Huang, Haifeng; Antonov, Ivan O.; Savee, John D.; Osborn, David L.; Zádor, Judit; Taatjes, Craig A.; Sheps, Leonid

2015-07-16

We have developed a multi-scale approach (Burke, M. P.; Klippenstein, S. J.; Harding, L. B. Proc. Combust. Inst. 2013, 34, 547–555.) to kinetic model formulation that directly incorporates elementary kinetic theories as a means to provide reliable, physics-based extrapolation to unexplored conditions. Here, we extend and generalize the multi-scale modeling strategy to treat systems of considerable complexity – involving multi-well reactions, potentially missing reactions, non-statistical product branching ratios, and non-Boltzmann (i.e. non-thermal) reactant distributions. The methodology is demonstrated here for a subsystem of low-temperature propane oxidation, as a representative system for low-temperature fuel oxidation. A multi-scale model is assembled and informed by a wide variety of targets that include ab initio calculations of molecular properties, rate constant measurements of isolated reactions, and complex systems measurements. Active model parameters are chosen to accommodate both “parametric” and “structural” uncertainties. Theoretical parameters (e.g. barrier heights) are included as active model parameters to account for parametric uncertainties in the theoretical treatment; experimental parameters (e.g. initial temperatures) are included to account for parametric uncertainties in the physical models of the experiments. RMG software is used to assess potential structural uncertainties due to missing reactions. Additionally, branching ratios among product channels are included as active model parameters to account for structural uncertainties related to difficulties in modeling sequences of multiple chemically activated steps. The approach is demonstrated here for interpreting time-resolved measurements of OH, HO2, n-propyl, i-propyl, propene, oxetane, and methyloxirane from photolysis-initiated low-temperature oxidation of propane at pressures from 4 to 60 Torr and temperatures from 300 to 700 K. In particular, the multi-scale informed

The Effect of Temperature on the Enzyme-Catalyzed Reaction: Insights from Thermodynamics

Science.gov (United States)

Aledo, Juan Carlos; Jimenez-Riveres, Susana; Tena, Manuel

2010-01-01

When teaching the effect of temperature on biochemical reactions, the problem is usually oversimplified by confining the thermal effect to the catalytic constant, which is identified with the rate constant of the elementary limiting step. Therefore, only positive values for activation energies and values greater than 1 for temperature coefficients…

Professional Identity and Burnout among Pre-School, Elementary, and Post-Elementary School Teachers in Israel

Science.gov (United States)

Fisherman, Shraga

2015-01-01

The novelty of the present study is its attempt to distinguish between pre-school, elementary, and post-elementary school teachers, regarding the relationship between professional identity and burnout. Two hundred and forty teachers responded to two questionnaires: professional identity and teacher burnout scales. Pre-school teachers were found to…

Elementary Thermal Operations

DEFF Research Database (Denmark)

Lostaglio, Matteo; Alhambra, Álvaro M.; Perry, Christopher

2018-01-01

To what extent do thermodynamic resource theories capture physically relevant constraints? Inspired by quantum computation, we define a set of elementary thermodynamic gates that only act on 2 energy levels of a system at a time. We show that this theory is well reproduced by a Jaynes-Cummings in......To what extent do thermodynamic resource theories capture physically relevant constraints? Inspired by quantum computation, we define a set of elementary thermodynamic gates that only act on 2 energy levels of a system at a time. We show that this theory is well reproduced by a Jaynes...

Products of the reaction between methylene iodide and tertiary arsines

International Nuclear Information System (INIS)

Gigauri, R.D.; Arabuli, L.G.; Machaidze, Z.I.; Rusiya, M.Sh.

2005-01-01

Iodides of iodomethylenetrialkyl(aryl) arsonium were synthesized with high yields as a result of interaction between methylene iodide and tertiary arsines. Exchange reactions of the iodides prepared with lead(II) nitrate in water-alcohol solutions gave rise to formation of iodomethylenetrialkyl(aryl) arsonium nitrates. All the products prepared were characterized by data of elementary analysis, IR spectroscopy, conductometry and melting points measurements [ru

On the invertibility of elementary operators

OpenAIRE

Boudi, Nadia; Bračič, Janko

2013-01-01

Let $\\mathscr{X}$ be a complex Banach space and $\\mathcal{L}(\\mathscr{X})$ be the algebra of all bounded linear operators on $\\mathscr{X}$. For a given elementary operator $\\Phi$ of length $2$ on $\\mathcal{L}(\\mathscr{X})$, we determine necessary and sufficient conditions for the existence of a solution of the equation ${\\rm X} \\Phi=0$ in the algebra of all elementary operators on $\\mathcal{L}(\\mathscr{X})$. Our approach allows us to characterize some invertible elementary operators of length...

Direct Dynamics Simulation of the Thermal 3CH2 + 3O2 Reaction. Rate Constant and Product Branching Ratios.

Science.gov (United States)

Lakshmanan, Sandhiya; Pratihar, Subha; Machado, Francisco Bolivar Correto; Hase, William Louis

2018-04-26

The reaction of 3CH2 with 3O2 is of fundamental importance in combustion and the reaction is complex as a result of multiple extremely exothermic product channels. In the present study, direct dynamics simulations were performed to study the reaction on both the singlet and triplet potential energy surfaces (PESs). The simulations were performed at the UM06/6-311++G(d,p) level of theory. Trajectories were calculated at a temperature of 300 K and all reactive trajectories proceeded through the carbonyl oxide Criegee intermediate, CH2OO, on both the singlet and triplet PESs. The triplet surface leads to only one product channel, H2CO + O(3P), while the singlet surface leads to 8 product channels with their relative importance as: CO + H2O > CO + OH + H ~ H2CO + O(1D) > HCO + OH ~ CO2 + H2 ~ CO + H2 + O(1D) > CO2 + H + H > HCO + O(1D) + H. Reaction on the singlet PES is barrierless, consistent with experiment and the total rate constant on the singlet surface is 0.93 ± 0.22 x 10-12 cm3molecule-1s-1 in comparison to the recommended experimental rate constant of 3.3 x 10-12 cm3molecule-1s-1. The simulation product yields for the singlet PES are compared with experiment and the most significant differences are for H, CO2, and H2O. Reaction on the triplet surface is also barrierless, inconsistent with experiment. A discussion is given of the need for future calculations to address the: (1) barrier on the triplet PES for 3CH2 + 3O2 → 3CH2OO; (2) temperature dependence of the 3CH2 + 3O2 reaction rate constant and product branching ratios; and (3) possible non-RRKM dynamics of the 1CH2OO Criegee intermediate.

Engineering at the Elementary Level

Science.gov (United States)

McGrew, Cheryl

2012-01-01

Can engineering technology be taught at the elementary level? Designing and building trebuchets, catapults, solar cars, and mousetrap vehicles in a west central Florida elementary class was considered very unusual in recent years. After a review of current research on failing schools and poor curriculum, the author wondered what her school could…

Liquid-Crystalline Ionic Liquids as Ordered Reaction Media for the Diels-Alder Reaction.

Science.gov (United States)

Bruce, Duncan W; Gao, Yanan; Canongia Lopes, José Nuno; Shimizu, Karina; Slattery, John M

2016-11-02

Liquid-crystalline ionic liquids (LCILs) are ordered materials that have untapped potential to be used as reaction media for synthetic chemistry. This paper investigates the potential for the ordered structures of LCILs to influence the stereochemical outcome of the Diels-Alder reaction between cyclopentadiene and methyl acrylate. The ratio of endo- to exo-product from this reaction was monitored for a range of ionic liquids (ILs) and LCILs. Comparison of the endo:exo ratios in these reactions as a function of cation, anion and liquid crystallinity of the reaction media, allowed for the effects of liquid crystallinity to be distinguished from anion effects or cation alkyl chain length effects. These data strongly suggest that the proportion of exo-product increases as the reaction media is changed from an isotropic IL to a LCIL. A detailed molecular dynamics (MD) study suggests that this effect is related to different hydrogen bonding interactions between the reaction media and the exo- and endo-transition states in solvents with layered, smectic ordering compared to those that are isotropic. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Adverse reactions to mosquito bites in scholars from Monterrey, Nuevo Leon, Mexico].

Science.gov (United States)

Manrique López, María Amelia; González Díaz, Sandra N; Arias Cruz, Alfredo; Sedó Mejía, Giovanni A; Canseco Villarreal, José Ignacio; Gómez Retamoza, Ernesto Antonio; Padrón López, Olga Magdalena; Cruz Moreno, Miguel Angel; Cisneros Salazar, Guillermo Daniel

2010-01-01

Allergic reactions to insect bites are a global problem, the true incidence and prevalence of morbidity from adverse reactions to mosquito bites are unknown. To describe the adverse reactions to mosquito bites in school-age children of Monterrey, Nuevo Leon. A cross-sectional descriptive study was made via a randomized application of questionnaires to children from public elementary schools in the metropolitan area of Monterrey, Nuevo Leon. A total of 11 public schools randomly selected were included in the study. One thousand questionnaires were submitted, of which 506 fulfilled the inclusion criteria; 55% were females. Seventy-six percent referred adverse reactions to mosquito bites, itching (75%) and rash (72%) being the most frequent ones, in the last 12 months. Adverse reactions to mosquito bites occur frequently. Early detection is important to establish a prompt treatment.

Explorations in Elementary Mathematical Modeling

Science.gov (United States)

Shahin, Mazen

2010-01-01

In this paper we will present the methodology and pedagogy of Elementary Mathematical Modeling as a one-semester course in the liberal arts core. We will focus on the elementary models in finance and business. The main mathematical tools in this course are the difference equations and matrix algebra. We also integrate computer technology and…

Assessing Elementary Algebra with STACK

Science.gov (United States)

Sangwin, Christopher J.

2007-01-01

This paper concerns computer aided assessment (CAA) of mathematics in which a computer algebra system (CAS) is used to help assess students' responses to elementary algebra questions. Using a methodology of documentary analysis, we examine what is taught in elementary algebra. The STACK CAA system, http://www.stack.bham.ac.uk/, which uses the CAS…

Elementary School Philosophy: A Response

Science.gov (United States)

Wartenberg, Thomas E.

2012-01-01

This article is a response to criticism of my book "Big Ideas for Little Kids." The main topics addressed are: Who is the audience for the book? Can people without formal philosophical training can be good facilitators of elementary school philosophy discussions? Is it important to assess attempts to teach philosophy in elementary school? Should…

Kinetic study of the dehydration reaction of lithium sulfate monohydrate crystals using microscopy and modeling

Energy Technology Data Exchange (ETDEWEB)

Lan, Shuiquan [Department of Mechanical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612AZ Eindhoven (Netherlands); Zondag, Herbert [Department of Mechanical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612AZ Eindhoven (Netherlands); Energy research Center of the Netherlands – ECN, P.O. Box 1, 1755ZG Petten (Netherlands); Steenhoven, Anton van [Department of Mechanical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612AZ Eindhoven (Netherlands); Rindt, Camilo, E-mail: c.c.m.rindt@tue.nl [Department of Mechanical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612AZ Eindhoven (Netherlands)

2015-12-10

Highlights: • Kinetics of Li{sub 2}SO{sub 4}·H{sub 2}O single crystals were modeled based on elementary processes. • Kinetics of nucleation and nuclei growth were studied by using optical microscopy. • A novel experiment was designed to visualize the reaction front into crystal bulk. • Fractional conversion was calculated and compared with TGA-experiments. - Abstract: Simulation of gas–solid reactions occurring in industrial processes requires a robust kinetic model to be applicable in a wide range of complicated reaction conditions. However, in literature it is often seen that even the same reaction under specific controlled conditions is interpreted with different kinetic models. In the present work, a phenomenological model based on nucleation and nuclei growth processes is presented to study the kinetics of the dehydration reaction of lithium sulfate monohydrate single crystals. The two elementary processes of the reaction, nucleation and nuclei growth, are characterized and quantified as a function of temperature by using optical microscopy experiments. The in-situ measured characteristics of the dehydration reaction provided confirmatory evidence that the rate of nucleation obeys an exponential law and the rate of nuclei growth is approximately constant. With knowledge acquired from the optical observations as inputs of the kinetic model, the fractional conversion of the dehydration reaction was calculated and compared with experimental results from thermogravimetric analysis (TGA). A satisfactory comparison was found both in isothermal and non-isothermal conditions. It is demonstrated that this knowledge-based model has a great potential to represent the gas–solid reaction kinetics in a wide range of process conditions regarding temperature, pressure and particle geometry.

Effect of excited states on thermonuclear reaction rates

International Nuclear Information System (INIS)

Sargood, D.G.

1983-01-01

Values of the ratio of the thermonuclear reaction rate of a reaction, with target nuclei in a thermal distribution of energy states, to the reaction rate with all target nuclei in their ground states are tabulated for neutron, proton and α-particle induced reactions on the naturally occurring nuclei from 20 Ne to 70 Zn, at temperatures of 1, 2, 3.5 and 5x10 9 K. The ratios are determined from reaction rates based on statistical model cross sections

Measurement of excitation functions and isomeric ratios of the 197Au(3He,xn)200- sup(x)Tl reactions, where x=2,3 and 4

International Nuclear Information System (INIS)

Vinagre Filho, U.M.

1983-01-01

The excitation functions and isomer ratios of the 197 Au( 3 He,xn) 200- sup(x)Tl reactions, with x = 2, 3 and 4, were measured at bombarding energies in the range from 15 to 36 MeV. The measured values were compared to those obtained with the use of the statistical an hybrid modeles, calculated by the ALICE code. Best fit was achieved using the simple statistical model. The results were also compared to those found in literature for the ( 3 He,xn) and ( 4 He,xn) reactions in gold. (Author) [pt

Longitudinal development of subtraction performance in elementary school.

Science.gov (United States)

Artemenko, Christina; Pixner, Silvia; Moeller, Korbinian; Nuerk, Hans-Christoph

2017-10-05

A major goal of education in elementary mathematics is the mastery of arithmetic operations. However, research on subtraction is rather scarce, probably because subtraction is often implicitly assumed to be cognitively similar to addition, its mathematical inverse. To evaluate this assumption, we examined the relation between the borrow effect in subtraction and the carry effect in addition, and the developmental trajectory of the borrow effect in children using a choice reaction paradigm in a longitudinal study. In contrast to the carry effect in adults, carry and borrow effects in children were found to be categorical rather than continuous. From grades 3 to 4, children became more proficient in two-digit subtraction in general, but not in performing the borrow operation in particular. Thus, we observed no specific developmental progress in place-value computation, but a general improvement in subtraction procedures. Statement of contribution What is already known on this subject? The borrow operation increases difficulty in two-digit subtraction in adults. The carry effect in addition, as the inverse operation of borrowing, comprises categorical and continuous processing characteristics. What does this study add? In contrast to the carry effect in adults, the borrow and carry effects are categorical in elementary school children. Children generally improve in subtraction performance from grades 3 to 4 but do not progress in place-value computation in particular. © 2017 The British Psychological Society.

Theoretical Studies of Elementary Hydrocarbon Species and Their Reactions

Energy Technology Data Exchange (ETDEWEB)

Allen, Wesley D. [University of Georgia, Department of Chemistry and Center for Computational Quantum Chemistry; Schaefer, Henry F. [University of Georgia, Center for Computational Quantum Chemistry

2018-04-08

The research program supported by this DOE grant carried out both methodological development and computational applications of first-principles theoretical chemistry based on quantum mechanical wavefunctions, as directed toward understanding and harnessing the fundamental chemical physics of combustion. To build and refine the world’s database of thermochemistry, spectroscopy, and chemical kinetics, predictive and definitive computational methods are needed that push the envelope of modern electronic structure theory. The application of such methods has been made to gain comprehensive knowledge of the paradigmatic reaction networks by which the n- and i-propyl, t-butyl, and n-butyl radicals are oxidized by O₂. Numerous ROO and QOOH intermediates in these R + O₂ reaction systems have been characterized along with the interconnecting isomerization transition states and the barriers leading to fragmentation. Other combustion-related intermediates have also been studied, including methylsulfinyl radical, cyclobutylidene, and radicals derived from acetaldehyde and vinyl alcohol. Theoretical advances have been achieved and made available to the scientific community by implementation into PSI4, an open-source electronic structure computer package emphasizing automation, advanced libraries, and interoperability. We have pursued the development of universal explicitly correlated methods applicable to general electronic wavefunctions, as well as a framework that allows multideterminant reference functions to be expressed as a single determinant from quasiparticle operators. Finally, a rigorous analytical tool for correlated wavefunctions has been created to elucidate dispersion interactions, which play essential roles in many areas of chemistry, but whose effects are often masked and enigmatic. Our research decomposes and analyzes the coupled-cluster electron correlation energy in molecular systems as a function of interelectronic distance. Concepts

Elementary Thermal Operations

DEFF Research Database (Denmark)

Lostaglio, Matteo; Alhambra, Álvaro M.; Perry, Christopher

2018-01-01

To what extent do thermodynamic resource theories capture physically relevant constraints? Inspired by quantum computation, we define a set of elementary thermodynamic gates that only act on 2 energy levels of a system at a time. We show that this theory is well reproduced by a Jaynes-Cummings in......To what extent do thermodynamic resource theories capture physically relevant constraints? Inspired by quantum computation, we define a set of elementary thermodynamic gates that only act on 2 energy levels of a system at a time. We show that this theory is well reproduced by a Jaynes......-Cummings interaction in rotating wave approximation and draw a connection to standard descriptions of thermalisation. We then prove that elementary thermal operations present tighter constraints on the allowed transformations than thermal operations. Mathematically, this illustrates the failure at finite temperature...... to do so, including necessary and sufficient conditions for a given change of the population to be possible. As an example, we describe the resource theory of the Jaynes-Cummings model. Finally, we initiate an investigation into how our resource theories can be applied to Heat Bath Algorithmic Cooling...

Preservice Elementary Teachers and the Fundamentals of Probability

Science.gov (United States)

Dollard, Clark

2011-01-01

This study examined how preservice elementary teachers think about situations involving probability. Twenty-four preservice elementary teachers who had not yet studied probability as part of their preservice elementary mathematics coursework were interviewed using a task-based interview. The participants' responses showed a wide variety of…

The isomeric ratios in photonuclear reactions of natural barium induced by bremsstrahlungs with endpoint energies in the giant dipole resonance region

International Nuclear Information System (INIS)

Tran Duc Thiep; Truong Thi An; Phan Viet Cuong; Nguyen The Vinh

2012-01-01

We have determined the isomeric ratios in 130 Ba(γ, n) 129m,g Ba, 132 Ba(γ, n) 131m,g Ba and 134 Ba(γ, n) 133m,g Ba photonuclear reactions of natural barium induced by bremsstrahlungs with end-point energies in the giant dipole resonance region. The investigated samples were irradiated at electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The gamma spectra of the samples irradiated were measured with spectroscopic system consisting of 8192 channel analyzer and high-energy resolution (180 keV at gamma ray 1332 keV of 60 Co) HP(Ge) semiconductor detector Canberra. The GENIE2000 (Canberra) computer program was used for data processing. The results were discussed and compared with those of other authors. (author)

On reaction of titanium polonides with carbon dioxide

International Nuclear Information System (INIS)

Abakumov, A.S.; Malyshev, M.L.; Reznikova, N.F.

1986-01-01

The reaction between titanium polonides and carbon dioxide has been studied by comparing titanium polonide thermal resistance in vacuum and in carbon dioxide. The investigation has shown that titanium mono- and semipolonides fail at temperatures below 350 deg C. Temperature dependence of polonium vapor pressure prepared at failure of the given polonides is determined by the radiotensiometry in carbon dioxide. Enthalpy calculated for this dependence is close to the enthalpy of elementary polonium evaporation in vacuum

Energy related applications of elementary particle physics

International Nuclear Information System (INIS)

Rafelski, J.

1991-01-01

The current research position is summarized, and what could be done in the future to clarify issues which were opened up by the research is indicated. Following on the discussion of the viability of catalyzed fusion, there is presented along with the key experimental results, a short account of the physics surrounding the subject. This is followed by a discussion of key research topics addressed. In consequence of the progress made, it appears that the feasibility of a small-scale fusion based on catalyzed reactions rests on either the remote chance that a yet undiscovered ultraheavy negatively charged elementary particle exists in Nature, or on the possible technical realization of a system based on muon-catalyzed fusion (MuCF) in high-density degenerate hydrogen plasma (density 1000 LHD, temperature O(100 eV)). The lattter is considered to have practical promise

Theoretical analysis of consecutive reactions in adiabatic stirred tank reactors

International Nuclear Information System (INIS)

Jo, Byung Wook; Kim, Sun Il; Hong, Won Hae; Cha, Wol Suk; Kim, Soong Pyung; Kim, Jung Gyu

1990-01-01

By mathematical model for the case of the consecutive first-order exothermic reaction in an adiabatic CSTR, the effects of the system parameter i. e. relative residence time, heat of reaction and thermal sensitivity of reaction rate constant, on the concentration profile of the intermediate product of a consecutive reaction were obtained as follows. For fixed values of the ratio of the reaction rate constants t 1 / t 2 , the ratio of the correponding system parameter α where α>1 and the sensitivities of the reaction rate constants S1 and S2, the maximum value of the intermediate production dimensionless concentration increases with increase in the values of the relative energy parameter E1 and E2 and it decreases with a decrease in E1 and E2. For fixed values of the ratio of the reaction rate constants t 1 / t 2 , the ratio of the corresponding system parameter α where α 1 and t 2 and it increases with a decrease in S1 and S2. For fixed values of the ratio of the reaction rate constants t 1 / t 2 , the ratio of the corresponding system parameters α where α=1 and the relative energy parameters E1 and E2, the maximum value of the intermediate product dimensionless is constant with either increase or decrease in the sensitivities of the reaction rate constants S1 and S2. (Author)

Awareness on Learning Disabilities among Elementary School Teachers

Science.gov (United States)

Menon K. P., Seema

2016-01-01

The study aims to find out the awareness on learning disabilities among elementary school teachers. The sample for the present study consisted of 500 elementary school teachers of Kerala. In this study the investigator used an Awareness Test on Learning Disabilities to measure the Awareness on Learning Disabilities among Elementary School…

Some problems of high-energy elementary particle physics

International Nuclear Information System (INIS)

Isaev, P.S.

1995-01-01

The problems of high-energy elementary particle physics are discussed. It is pointed out that the modern theory of elementary-particle physics has no solutions of some large physical problems: origin of the mass, electric charge, identity of particle masses, change of the mass of elementary particles in time and others. 7 refs

Decomposition reaction rate of BCl3-C3H6(propene)-H2 in the gas phase.

Science.gov (United States)

Xiao, Jun; Su, Kehe; Liu, Yan; Ren, Hongjiang; Zeng, Qingfeng; Cheng, Laifei; Zhang, Litong

2012-07-05

The decomposition reaction rate in the BCl(3)-C(3)H(6)-H(2) gas phase reaction system in preparing boron carbides was investigated based on the most favorable reaction pathways proposed by Jiang et al. [Theor. Chem. Accs. 2010, 127, 519] and Yang et al. [J. Theor. Comput. Chem. 2012, 11, 53]. The rate constants of all the elementary reactions were evaluated with the variational transition state theory. The vibrational frequencies for the stationary points as well as the selected points along the minimum energy paths (MEPs) were calculated with density functional theory at the B3PW91/6-311G(d,p) level and the energies were refined with the accurate model chemistry method G3(MP2). For the elementary reaction associated with a transition state, the MEP was obtained with the intrinsic reaction coordinates, while for the elementary reaction without transition state, the relaxed potential energy surface scan was employed to obtain the MEP. The rate constants were calculated for temperatures within 200-2000 K and fitted into three-parameter Arrhenius expressions. The reaction rates were investigated by using the COMSOL software to solve numerically the coupled differential rate equations. The results show that the reactions are, consistent with the experiments, appropriate at 1100-1500 K with the reaction time of 30 s for 1100 K, 1.5 s for 1200 K, 0.12 s for 1300 K, 0.011 s for 1400 K, or 0.001 s for 1500 K, for propene being almost completely consumed. The completely dissociated species, boron carbides C(3)B, C(2)B, and CB, have very low concentrations, and C(3)B is the main product at higher temperatures, while C(2)B is the main product at lower temperatures. For the reaction time 1 s, all these concentrations approach into a nearly constant. The maximum value (in mol/m(3)) is for the highest temperature 1500 K with the orders of -13, -17, and -23 for C(3)B, C(2)B, and CB, respectively. It was also found that the logarithm of the overall reaction rate and reciprocal

On the ontology of the elementary particles. A philosophical analysis of the actual elementary-particle physics

International Nuclear Information System (INIS)

Brueckner, Thomas Christian

2015-01-01

After a description of the standard model of elementary-particle physics the author describes structuralistic reconstructions. Then the problem of the theoretical terms is discussed. Therafter the reconstruction of the standard-model elementary particles is described. Finally the ontology of leptons, quarks and both free and in atoms bound protons is considered.

Fostering Student Sense Making in Elementary Science Learning Environments: Elementary Teachers' Use of Science Curriculum Materials to Promote Explanation Construction

Science.gov (United States)

Zangori, Laura; Forbes, Cory T.; Biggers, Mandy

2013-01-01

While research has shown that elementary (K-5) students are capable of engaging in the scientific practice of explanation construction, commonly-used elementary science curriculum materials may not always afford them opportunities to do so. As a result, elementary teachers must often adapt their science curriculum materials to better support…

A high-temperature shock tube kinetic study for the branching ratios of isobutene+OH reaction

KAUST Repository

Khaled, Fathi; Giri, Binod; Farooq, Aamir

2016-01-01

Isobutene is an important intermediate formed during the oxidation of branched alkanes. It also appears as a byproduct during the combustion of methyl-tert-butyl-ether (MTBE) which is used as octane enhancer in gasolines. To understand better the oxidation kinetics of isobutene, we have measured the rate coefficients for the reaction of OH radicals with isobutene (HCC(CH)) behind reflected shock waves over the temperature range of 830-1289K and pressures near 1.5atm. The reaction progress was followed by measuring mole fraction of OH radicals near 306.7nm using UV laser absorption technique. Three deuterated isotopes, isobutene-1-d2 (DCC(CH)), isobutene-3-d6 (HCC(CD)) and isobutene-d8 (DCC(CD)) were employed to elucidate branching ratios of the allylic and vinylic H-abstraction from isobutene by OH radicals. H-abstraction from the allylic sites was found to be dominant and constituted about 75% of the total rate in the entire temperature range of the current work. The derived three-parameter Arrhenius expressions for site-specific H- and D- abstraction rates over 830-1289K are (units:cm mol s):k3,H=6.98×106(TK)1.77exp(-136.6KT) k3,D=4.42×106(TK)1.8exp(-361.7KT) k1,H=6.25×105(TK)2.16exp(-711.6KT) k1,D=3.13×107(TK)1.67exp(-1814KT) The subscript of . k identifies the position of H or D atom in isobutene according to the IUPAC nomenclature of alkenes.

A high-temperature shock tube kinetic study for the branching ratios of isobutene+OH reaction

KAUST Repository

Khaled, Fathi

2016-10-11

Isobutene is an important intermediate formed during the oxidation of branched alkanes. It also appears as a byproduct during the combustion of methyl-tert-butyl-ether (MTBE) which is used as octane enhancer in gasolines. To understand better the oxidation kinetics of isobutene, we have measured the rate coefficients for the reaction of OH radicals with isobutene (HCC(CH)) behind reflected shock waves over the temperature range of 830-1289K and pressures near 1.5atm. The reaction progress was followed by measuring mole fraction of OH radicals near 306.7nm using UV laser absorption technique. Three deuterated isotopes, isobutene-1-d2 (DCC(CH)), isobutene-3-d6 (HCC(CD)) and isobutene-d8 (DCC(CD)) were employed to elucidate branching ratios of the allylic and vinylic H-abstraction from isobutene by OH radicals. H-abstraction from the allylic sites was found to be dominant and constituted about 75% of the total rate in the entire temperature range of the current work. The derived three-parameter Arrhenius expressions for site-specific H- and D- abstraction rates over 830-1289K are (units:cm mol s):k3,H=6.98×106(TK)1.77exp(-136.6KT) k3,D=4.42×106(TK)1.8exp(-361.7KT) k1,H=6.25×105(TK)2.16exp(-711.6KT) k1,D=3.13×107(TK)1.67exp(-1814KT) The subscript of . k identifies the position of H or D atom in isobutene according to the IUPAC nomenclature of alkenes.

The ratio method: a new way to look at halo nuclei

Directory of Open Access Journals (Sweden)

Capel P.

2014-03-01

Full Text Available A new reaction observable is presented to study exotic loosely-bound structures, such as halo nuclei. It consists of the ratio of two angular distributions, e. g. one for breakup and one for elastic scattering. This ratio is nearly independent of the reaction mechanism and is very sensitive to the projectile structure. This new ratio method is illustrated on the particular case of 11Be, the archetypal one-neutron halo nucleus.

Data characterizing the energetics of enzyme-catalyzed hydrolysis and transglycosylation reactions by DFT cluster model calculations

Directory of Open Access Journals (Sweden)

Jitrayut Jitonnom

2018-04-01

Full Text Available The data presented in this paper are related to the research article entitled “QM/MM modeling of the hydrolysis and transfructosylation reactions of fructosyltransferase from Aspergillus japonicas, an enzyme that produces prebiotic fructooligosaccharide” (Jitonnom et al., 2018 [1]. This paper presents the procedure and data for characterizing the whole relative energy profiles of hydrolysis and transglycosylation reactions whose elementary steps differ in chemical composition. The data also reflects the choices of the QM cluster model, the functional/basis set method and the equations in determining the reaction energetics.

Receipt of special education services following elementary school grade retention.

Science.gov (United States)

Silverstein, Michael; Guppy, Nicole; Young, Robin; Augustyn, Marilyn

2009-06-01

To estimate the proportion of children who receive an Individualized Education Program (IEP) following grade retention in elementary school. Longitudinal cohort study. Children retained in kindergarten or first (K/1) grade and third grade, presumably for academic reasons, were followed up through fifth grade. Presence or absence of an IEP. A total of 300 children retained in K/1 and 80 retained in third grade were included in the study. Of the K/1 retainees, 68.9% never received an IEP during the subsequent 4 to 5 years; of the third-grade retainees, 72.3% never received an IEP. Kindergarten/first-grade retainees in the highest quintile for socioeconomic status and those with suburban residence were less likely to receive an IEP than retained children in all other socioeconomic status quintiles (adjusted odds ratio, 0.17; 95% confidence interval, 0.05-0.62) and in rural communities (0.16; 0.06-0.44). Among K/1 retainees with persistently low academic achievement in math and reading, as assessed by standardized testing, 38.2% and 29.7%, respectively, never received an IEP. Most children retained in K/1 or third grade for academic reasons, including many of those who demonstrated sustained academic difficulties, never received an IEP during elementary school. Further studies are important to elucidate whether retained elementary schoolchildren are being denied their rights to special education services. In the meantime, early-grade retention may provide an opportunity for pediatricians to help families advocate for appropriate special education evaluations for children experiencing school difficulties.

Elementary particle theory

International Nuclear Information System (INIS)

Marciano, W.J.

1984-12-01

The present state of the art in elementary particle theory is reviewed. Topics include quantum electrodynamics, weak interactions, electroweak unification, quantum chromodynamics, and grand unified theories. 113 references

Cosmic objects and elementary particles

Energy Technology Data Exchange (ETDEWEB)

Rozental, I L [AN SSSR, Moscow. Inst. Kosmicheskikh Issledovanij

1977-02-01

Considered are the connections between the parameters of elementary particles (mass ''size'') and the characteristics of stars (the main sequence stars, white dwarf stars and pulsars). Presented is the elementary theory of black hole radiation in the framework of which all the regularities of the process are derived. The emphiric numerical sequence connecting nucleon mass and universe constants (G, h, c) with the masses of some cosmic objects is given.

Neoclassical theory of elementary charges with spin of 1/2

Energy Technology Data Exchange (ETDEWEB)

Babin, Anatoli; Figotin, Alexander [Department of Mathematics University of California at Irvine, Irvine, California 92697-3875 (United States)

2014-08-15

We advance here our neoclassical theory of elementary charges by integrating into it the concept of spin of 1/2. The developed spinorial version of our theory has many important features identical to those of the Dirac theory such as the gyromagnetic ratio, expressions for currents including the spin current, and antimatter states. In our theory, the concepts of charge and anticharge relate naturally to their “spin” in its rest frame in two opposite directions. An important difference with the Dirac theory is that both the charge and anticharge energies are positive whereas their frequencies have opposite signs.

Transport description of damped nuclear reactions

International Nuclear Information System (INIS)

Randrup, J.

1983-04-01

Part I is an elementary introduction to the general transport theory of nuclear dynamics. It can be read without any special knowledge of the field, although basic quantum mechanics is required for the formal derivation of the general expression for the transport coefficients. The results can also be used in a wider context than the present one. Part II gives the student an up-to-date orientation about recent progress in the understanding of the angular-momentum variables in damped reactions. The emphasis is here on the qualitative understanding of the physics rather than the, at times somewhat tedious, formal derivations

Military Deployment and Elementary Student Achievement

Science.gov (United States)

Phelps, Terri; Dunham, Mardis; Lyons, Robert

2010-01-01

This study investigated the impact that military deployment has upon academic achievement of elementary school students. TerraNova test scores of 137 fourth and fifth grade students in two elementary schools with a high proportion of military dependent children were examined for two consecutive years. Although the academic test performance fell…

Applying Disciplinary Literacy in Elementary Geography

Science.gov (United States)

Britt, Judy; Ming, Kavin

2017-01-01

In this article, a social studies teacher and a literacy teacher describe a vision for social studies that highlights reading practices that foster disciplinary literacy in elementary geography. Their purpose is to share a practical approach for enriching elementary social studies lessons and activities with a geographic lens. During the…

Measurement of flux-weighted average cross-sections and isomeric yield ratios for {sup 103}Rh(γ, xn) reactions in the bremsstrahlung end-point energies of 55 and 60 MeV

Energy Technology Data Exchange (ETDEWEB)

Shakilur Rahman, Md.; Kim, Kwangsoo; Kim, Guinyun; Nadeem, Muhammad; Thi Hien, Nguyen; Shahid, Muhammad [Kyungpook National University, Department of Physics, Daegu (Korea, Republic of); Naik, Haladhara [Bhabha Atomic Research Centre, Radiochemistry Division, Mumbai (India); Yang, Sung-Chul; Cho, Young-Sik; Lee, Young-Ouk [Korea Atomic Energy Research Institute, Nuclear Data Center, Daejeon (Korea, Republic of); Shin, Sung-Gyun; Cho, Moo-Hyun [Pohang University of Science and Technology, Division of Advanced Nuclear Engineering, Pohang (Korea, Republic of); Woo Lee, Man; Kang, Yeong-Rok; Yang, Gwang-Mo [Dongnam Institute of Radiological and Medical Science, Research Center, Busan (Korea, Republic of); Ro, Tae-Ik [Dong-A University, Department of Materials Physics, Busan (Korea, Republic of)

2016-07-15

We measured the flux-weighted average cross-sections and the isomeric yield ratios of {sup 99m,g,100m,g,101m,g,102m,g}Rh in the {sup 103}Rh(γ, xn) reactions with the bremsstrahlung end-point energies of 55 and 60 MeV by the activation and the off-line γ-ray spectrometric technique, using the 100 MeV electron linac at the Pohang Accelerator Laboratory (PAL), Korea. The flux-weighted average cross-sections were calculated by using the computer code TALYS 1.6 based on mono-energetic photons, and compared with the present experimental data. The flux-weighted average cross-sections of {sup 103}Rh(γ, xn) reactions in intermediate bremsstrahlung energies are the first time measurement and are found to increase from their threshold value to a particular value, where the other reaction channels open up. Thereafter, it decreases with bremsstrahlung energy due to its partition in different reaction channels. The isomeric yield ratios (IR) of {sup 99m,g,100m,g,101m,g,102m,g}Rh in the {sup 103}Rh(γ, xn) reactions from the present work were compared with the literature data in the {sup 103}Rh(d, x), {sup 102-99}Ru(p, x), {sup 103}Rh(α, αn), {sup 103}Rh(α, 2p3n), {sup 102}Ru({sup 3}He, x), and {sup 103}Rh(γ, xn) reactions. It was found that the IR values of {sup 102,101,100,99}Rh in all these reactions increase with the projectile energy, which indicates the role of excitation energy. At the same excitation energy, the IR values of {sup 102,101,100,99}Rh are higher in the charged particle-induced reactions than in the photon-induced reaction, which indicates the role of input angular momentum. (orig.)

A high-performance liquid chromatography-electronic circular dichroism online method for assessing the absolute enantiomeric excess and conversion ratio of asymmetric reactions

Science.gov (United States)

Zhang, Xiang; Wang, Mingchao; Li, Li; Yin, Dali

2017-03-01

Asymmetric reactions often need to be evaluated during the synthesis of chiral compounds. However, traditional evaluation methods require the isolation of the individual enantiomer, which is tedious and time-consuming. Thus, it is desirable to develop simple, practical online detection methods. We developed a method based on high-performance liquid chromatography-electronic circular dichroism (HPLC-ECD) that simultaneously analyzes the material conversion ratio and absolute optical purity of each enantiomer. In particular, only a reverse-phase C18 column instead of a chiral column is required in our method because the ECD measurement provides a g-factor that describes the ratio of each enantiomer in the mixtures. We used our method to analyze the asymmetric hydrosilylation of β-enamino esters, and we discussed the advantage, feasibility, and effectiveness of this new methodology.

Subsequent development of the normal temperature fusion reaction. Joon kakuyugo sonogo no shinten

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, T. (Hokkaido University, Sapporo (Japan). Faculty of Engineering)

1991-04-24

This paper reports on a NATTOH model made public in May 1989 by T. Matsumoto who took notice of abnormality of the normal temperature fusion reaction. The NATTO model is based on a chain reaction by hydrogen with a hydrogen-catalyzed fusion reaction which is the normal temperature fusion reaction as an elementary process. If a high temperature fusion reaction is a small-size simulation of the fusion reaction rising on the surface of the sparkling star like the sun, the normal temperature fusion reaction can be a small-size simulation of the phenomena in the last years of the star in the far distance of the space. This gives reality to the normal temperature fusion reaction. The reaction mechanism of the normal temperature fusion reaction is almost being clarified by a NATTOH model. There remain problems on a possibility of generation of unknown radioactive rays and identification of radioactive wastes, but it seems that a prospect of commercialization can be talked about now. As for the utilization as energy, sea water may be used as it is. 10 ref., 5 figs.

Numerical simulation of hydrogen-air reacting flows in rectangular channels with catalytic surface reactions

Science.gov (United States)

Amano, Ryoichi S.; Abou-Ellail, Mohsen M.; Elhaw, Samer; Saeed Ibrahim, Mohamed

2013-09-01

In this work a prediction was numerically modeled for a catalytically stabilized thermal combustion of a lean homogeneous mixture of air and hydrogen. The mixture flows in a narrow rectangular channel lined with a thin coating of platinum catalyst. The solution using an in-house code is based on the steady state partial differential continuity, momentum and energy conservation equations for the mixture and species involved in the reactions. A marching technique is used along the streamwise direction to solve the 2-D plane-symmetric laminar flow of the gas. Two chemical kinetic reaction mechanisms were included; one for the gas phase reactions consisting of 17 elementary reactions; of which 7 are forward-backward reactions while the other mechanism is for the surface reactions—which are the prime mover of the combustion under a lean mixture condition—consisting of 16 elementary reactions. The results were compared with a former congruent experimental work where temperature was measured using thermocouples, while using PLIF laser for measuring water and hydrogen mole fractions. The comparison showed good agreement. More results for the velocities, mole fractions of other species were carried out across the transverse and along the streamwise directions providing a complete picture of overall mechanism—gas and surface—and on the production, consumptions and travel of the different species. The variations of the average OH mole fraction with the streamwise direction showed a sudden increase in the region where the ignition occurred. Also the rate of reactions of the entire surface species were calculated along the streamwise direction and a surface water production flux equation was derived by calculating the law of mass action's constants from the concentrations of hydrogen, oxygen and the rate of formation of water near the surface.

Physics through the 1990s: Elementary-particle physics

International Nuclear Information System (INIS)

Kirk, W.T.

1986-01-01

This report on elementary-particle physics is part of an overall survey of physics carried out for the National Academy of Sciences by the National Research Council. The panel that wrote this report had three goals. The first goal was to explain the nature of elementary-particle physics and to describe how research is carried out in this field. The second goal was to summarize our present knowledge of the elementary particles and the fundamental forces. The third goal was to consider the future course of elementary-particle physics research and to propose a program for this research in the United States. All of these goals are covered in this report

On Elementary and Algebraic Cellular Automata

Science.gov (United States)

Gulak, Yuriy

In this paper we study elementary cellular automata from an algebraic viewpoint. The goal is to relate the emergent complex behavior observed in such systems with the properties of corresponding algebraic structures. We introduce algebraic cellular automata as a natural generalization of elementary ones and discuss their applications as generic models of complex systems.

Elementary topology problem textbook

CERN Document Server

Viro, O Ya; Netsvetaev, N Yu; Kharlamov, V M

2008-01-01

This textbook on elementary topology contains a detailed introduction to general topology and an introduction to algebraic topology via its most classical and elementary segment centered at the notions of fundamental group and covering space. The book is tailored for the reader who is determined to work actively. The proofs of theorems are separated from their formulations and are gathered at the end of each chapter. This makes the book look like a pure problem book and encourages the reader to think through each formulation. A reader who prefers a more traditional style can either find the pr

STEM Is Elementary: Challenges Faced by Elementary Teachers in the Era of the Next Generation Science Standards

Science.gov (United States)

Isabelle, Aaron D.

2017-01-01

For students to achieve the goals of the Next Generation Science Standards (NGSS) by Grade 12, thinking and acting like scientists and engineers must begin in the elementary grades. However, elementary teachers may find this challenging -because language arts and mathematics still dominate many classrooms--often at the expense of science. This…

Place-based Learning About Climate with Elementary GLOBE

Science.gov (United States)

Hatheway, B.; Gardiner, L. S.; Harte, T.; Stanitski, D.; Taylor, J.

2017-12-01

Place-based education - helping students make connections between themselves, their community, and their local environment - is an important tool to help young learners understand their regional climate and start to learn about climate and environmental change. Elementary GLOBE storybooks and learning activities allow opportunities for place-based education instructional strategies about climate. In particular, two modules in the Elementary GLOBE unit - Seasons and Climate - provide opportunities for students to explore their local climate and environment. The storybooks and activities also make connections to other parts of elementary curriculum, such as arts, geography, and math. Over the long term, place-based education can also encourage students to be stewards of their local environment. A strong sense of place may help students to see themselves as stakeholders in their community and its resilience. In places that are particularly vulnerable to the impacts of climate and environmental change and the economic, social, and environmental tradeoffs of community decisions, helping young students developing a sense of place and to see the connection between Earth science, local community, and their lives can have a lasting impact on how a community evolves for decades to come. Elementary GLOBE was designed to help elementary teachers (i.e., grades K-4) integrate Earth system science topics into their curriculum as they teach literacy skills to students. This suite of instructional materials includes seven modules. Each module contains a science-based storybook and learning activities that support the science content addressed in the storybooks. Elementary GLOBE modules feature air quality, climate, clouds, Earth system, seasons, soil, and water. New eBooks allow students to read stories on computers or tablets, with the option of listening to each story with an audio recording. A new Elementary GLOBE Teacher Implementation Guide, published in 2017, provides

Norms of certain Jordan elementary operators

Science.gov (United States)

Zhang, Xiaoli; Ji, Guoxing

2008-10-01

Let be a complex Hilbert space and let denote the algebra of all bounded linear operators on . For , the Jordan elementary operator UA,B is defined by UA,B(X)=AXB+BXA, . In this short note, we discuss the norm of UA,B. We show that if and ||UA,B||=||A||||B||, then either AB* or B*A is 0. We give some examples of Jordan elementary operators UA,B such that ||UA,B||=||A||||B|| but AB*[not equal to]0 and B*A[not equal to]0, which answer negatively a question posed by M. Boumazgour in [M. Boumazgour, Norm inequalities for sums of two basic elementary operators, J. Math. Anal. Appl. 342 (2008) 386-393].

Elementary School Organization: Self-Contained and Departmentalized Classroom Structures.

Science.gov (United States)

Des Moines Public Schools, IA.

Surveys were conducted to investigate contemporary thought regarding organizational practices at the elementary level, with particular attention to identifying the extent to which departmentalization was supported by research and actually employed in 24 elementary schools in the Midwest and in 41 Des Moines elementary schools. Four committees…

Charm-quarks and new elementary particles

International Nuclear Information System (INIS)

Petersen, J.L.

1978-01-01

This is the first part of an extensive paper which discusses: the Nobel prize in physics 1976; discovery of the J/psi-particle; elementary particles and elementary building blocks; the four reciprocal effects; gauge theories; quark-antiquark reciprocal effects; the high-energy approximation; a simple quark-antiquark potential; and quark diagrams and the Zweig rule. (Auth.)

Elementary particle physics at the University of Florida

International Nuclear Information System (INIS)

1991-01-01

This report discusses research in the following areas: theoretical elementary particle physics; experimental elementary particle physics; axion project; SSC detector development; and computer acquisition. (LSP)

Elementary particle physics at the University of Florida

Energy Technology Data Exchange (ETDEWEB)

1991-12-01

This report discusses research in the following areas: theoretical elementary particle physics; experimental elementary particle physics; axion project; SSC detector development; and computer acquisition. (LSP).

Elementary functions algorithms and implementation

CERN Document Server

Muller, Jean-Michel

2016-01-01

This textbook presents the concepts and tools necessary to understand, build, and implement algorithms for computing elementary functions (e.g., logarithms, exponentials, and the trigonometric functions). Both hardware- and software-oriented algorithms are included, along with issues related to accurate floating-point implementation. This third edition has been updated and expanded to incorporate the most recent advances in the field, new elementary function algorithms, and function software. After a preliminary chapter that briefly introduces some fundamental concepts of computer arithmetic, such as floating-point arithmetic and redundant number systems, the text is divided into three main parts. Part I considers the computation of elementary functions using algorithms based on polynomial or rational approximations and using table-based methods; the final chapter in this section deals with basic principles of multiple-precision arithmetic. Part II is devoted to a presentation of “shift-and-add” algorithm...

One- and two-dimensional infrared spectroscopic studies of solution-phase homogeneous catalysis and spin-forbidden reactions

Energy Technology Data Exchange (ETDEWEB)

Sawyer, Karma Rae [Univ. of California, Berkeley, CA (United States)

2008-12-01

Understanding chemical reactions requires the knowledge of the elementary steps of breaking and making bonds, and often a variety of experimental techniques are needed to achieve this goal. The initial steps occur on the femto- through picosecond time-scales, requiring the use of ultrafast spectroscopic methods, while the rate-limiting steps often occur more slowly, requiring alternative techniques. Ultrafast one and two-dimensional infrared and step-scan FTIR spectroscopies are used to investigate the photochemical reactions of four organometallic complexes. The analysis leads to a detailed understanding of mechanisms that are general in nature and may be applicable to a variety of reactions.

Theoretical nuclear reaction and structure studies using hyperons and photons

International Nuclear Information System (INIS)

Cotanch, S.R.

1992-01-01

Research in three principal areas is summarized: (1) Work in elementary hadron structure seeks to further the understanding of hadron structure within the framework of quantum chromodynamics (QCD) and QCD-based models. A comparative study of meson properties employed three relativistic models: an extended Dziembowski model, a generalized light-front approach, and a completely covariant null plane approach. (2) Work on the electromagnetic production of strangeness addressed systems involving the strange quark (hyperons) and hyperon electromagnetic production and radiative capture processes. (3) In the work on medium-energy photonuclear reactions, a large-scale continuum shell-model calculation was performed for (γ,N) and (N,γ) reactions at low and medium energies spanning the Δ isobar region

Elementary process theory axiomatic introduction and applications

CERN Document Server

Cabbolet, Marcoen J T F

2011-01-01

Modern physics lacks a unitary theory that applies to all four fundamental interactions. This PhD thesis is a proposal for a single, complete, and coherent scheme of mathematically formulated elementary laws of nature. While the first chapter presents the general background, the second chapter addresses the method by which the main result has been developed. The next three chapters rigorously introduce the Elementary Process Theory, its mathematical foundations, and its applications to physics, cosmology and philosophy of mind. The final two chapters discuss the results and present the conclusions. Summarizing, the Elementary Process Theory is a scheme of seven well-formed closed expressions, written in the mathematical language of set matrix theory – a generalization of Zermelo-Fraenkel set theory. In the physical world, these seven expressions can be interpreted as elementary principles governing the universe at supersmall scale. The author critically confronts the theory with Quantum Mechanics and Genera...

Lubin-Tate extensions, an elementary approach

International Nuclear Information System (INIS)

Ershov, Yu L

2007-01-01

We give an elementary proof of the assertion that the Lubin-Tate extension L≥K is an Abelian extension whose Galois group is isomorphic to U K /N L/K (U L ) for arbitrary fields K that have Henselian discrete valuation rings with finite residue fields. The term 'elementary' only means that the proofs are algebraic (that is, no transcedental methods are used)

Elementary number theory with programming

CERN Document Server

Lewinter, Marty

2015-01-01

A successful presentation of the fundamental concepts of number theory and computer programming Bridging an existing gap between mathematics and programming, Elementary Number Theory with Programming provides a unique introduction to elementary number theory with fundamental coverage of computer programming. Written by highly-qualified experts in the fields of computer science and mathematics, the book features accessible coverage for readers with various levels of experience and explores number theory in the context of programming without relying on advanced prerequisite knowledge and con

Measurement of photo-neutron cross sections and isomeric yield ratios in the {sup 89}Y(γ,xn){sup 89-x}Y reactions at the bremsstrahlung end-point energies of 65, 70 and 75 MeV

Energy Technology Data Exchange (ETDEWEB)

Tatari, Mansoureh [Yazd Univ. (Iran, Islamic Republic of). Physics Dept.; Naik, Haladhara [Bhabha Atomic Research Centre, Mumbai (India). Radiochemistry Div.; Kim, Guinyun; Kim, Kwangsoo [Kyungpook National Univ., Daegu (Korea, Republic of). Dept. of Physics; Shin, Sung-Gyun; Cho, Moo-Hyun [Pohang Univ. of Science and Technology (Korea, Republic of). Div. of Advanced Nuclear Engineering

2017-07-01

The flux-weighted average cross sections of the {sup 89}Y(γ,xn; x=1-4){sup 89-x}Y reactions and the isomeric yield ratios of the {sup 87m,g}Y, {sup 86m,g}Y, and {sup 85m,g}Y radionuclides produced in these reactions with the bremsstrahlung end-point energies of 65, 70 and 75 MeV have been determined by an activation and off-line γ-ray spectrometric technique using the 100 MeV electron linac in Pohang Accelerator Laboratory, Korea. The theoretical {sup 89}Y(γ,xn; x=1-4){sup 89-x}Y reaction cross sections for mono-energetic photons have been calculated using the computer code TALYS 1.6. Then the flux-weighted theoretical values were obtained to compare with the present data. The flux-weighted experimental and theoretical {sup 89}Y(γ,xn; x=1-4){sup 89-x}Y reaction cross sections increase very fast from the threshold values to a certain bremsstrahlung energy, where the other reaction channels open up. Thereafter it remains constant a while and then slowly decreases with the increase of cross sections for other reactions. Similarly, the isomeric yield ratios of {sup 87m,g}Y, {sup 86m,g}Y and {sup 85m,g}Y in the {sup 89}Y(γ,xn; x=2-4){sup 89-x}Y reactions from the present work and literature data show an increasing trend from their respective threshold values to a certain bremsstrahlung energy. After a certain point of energy, the isomeric yield ratios increase slowly with the bremsstrahlung energy. These observations indicate the role of excitation energy and its partitioning in different reaction channels.

8th Symposium on elementary processes and chemical reactions in low temperature plasma. Pt. 1 and 2

International Nuclear Information System (INIS)

Morvova, M.

1990-11-01

The document contains invited papers on low temperature plasma physics and its application. Among them, 9 papers deal with the experimental and theoretical investigation and modelling of elementary plasma processes and particle kinematics in electric discharges of various type and purpose. Each of the following 3 papers presents a survey of some advanced plasma technology, as are laser plasma chemistry, plasma production of diamond-like carbon films and of special fine powders. The ionized Van der Waals clusters, shock waves in interplanetary plasma, and plasma acceleration in electromagnetic plasma launchers are the topics of the remaining three papers. (J.U.)

Fabrication of steel matrix composites locally reinforced with different ratios of TiC/TiB2 particulates using SHS reactions of Ni-Ti-B4C and Ni-Ti-B4C-C systems during casting

International Nuclear Information System (INIS)

Yang Yafeng; Wang Huiyuan; Liang Yunhong; Zhao Ruyi; Jiang Qichuan

2007-01-01

Steel matrix composites locally reinforced with different molar ratios of in situ TiC/TiB 2 particulates (2:1, 1:1 and 1:2, respectively) have been fabricated successfully utilizing the self-propagating high-temperature synthesis (SHS) reactions of Ni-Ti-B 4 C and Ni-Ti-B 4 C-C systems during casting. Differential thermal analysis (DTA) and X-ray diffraction (XRD) results reveal that the exothermic reactions of the Ni-Ti-B 4 C and Ni-Ti-B 4 C-C systems proceed in such a way that Ni initially reacts with B 4 C and Ti to form Ni 2 B and Ti 2 Ni compounds, respectively, with heat evolution at 1037 deg. C; Subsequently, the external heat and the evolved heat from these exothermic reactions promote the reactions forming TiC and TiB 2 at 1133 deg. C. In the composites reinforced with 1:2 molar ratio of TiC/TiB 2 , almost all TiB 2 grains have clubbed structures, while TiC grains exhibit near-spherical morphologies. Furthermore, TiB 2 grain sizes decrease, with the increase of TiC content. In particular, in the composites reinforced with 2:1 molar ratio of TiC/TiB 2 , it is difficult to find the clubbed TiB 2 grains. Macro-pores and blowholes are absent in the local reinforcing region of the composites reinforced with 1:1 and 1:2 molar ratios of TiC/TiB 2 , while a few macro-pores can be observed in the composite reinforced with 2:1 molar ratio of TiC/TiB 2 . Moreover, the densities of the composites reinforced with 1:1 and 1:2 molar ratios of TiC/TiB 2 are higher than that of the composite reinforced with 2:1 molar ratio of TiC/TiB 2 . The composite reinforced with 1:2 molar ratio of TiC/TiB 2 has the highest hardness and the best wear resistance

College and Career Readiness in Elementary Schools

Science.gov (United States)

Pulliam, Nicole; Bartek, Samantha

2018-01-01

This conceptual article will provide an in-depth exploration of the relevant literature focused on college and career readiness interventions in elementary schools. Beginning with a theoretical framework, a rationale is provided for early intervention by elementary school counselors. While professional guidelines and standards exist supporting…

Elementary processes in plasma-surface interactions with emphasis on ions

International Nuclear Information System (INIS)

Zalm, P.C.

1985-01-01

Elementary processes occurring at solid surfaces immersed in low pressure plasmas are reviewed. In particular mechanisms leading to anisotropic or directional etching are discussed. The crucial role of ion bombardment is emphasized. First a brief summary of the interaction of (excited) neutrals, ions and electrons with targets is given. Next various aspects of sputter-etching with noble gas and reactive ions are surveyed. Finally it will be argued that synergistic effects, invoked by ion bombardment of a surface under simultaneous exposure to a reactive gas flux, are foremost important in explaining anisotropic plasma etching. It is shown that the role of the ions is not merely to stimulate the chemical reaction path but rather that the active gas flow chemically enhances the sputtering. (author)

Analyzing powers and isotope ratios for the natAg(rvec p, intermediate-mass fragment) reaction at 200 MeV

International Nuclear Information System (INIS)

Renshaw, E.; Yennello, S.J.; Kwiatkowski, K.; Planeta, R.; Woo, L.W.; Viola, V.E.

1991-01-01

Analyzing powers and isotope ratios have been measured for ejectiles with Z≤7 emitted at forward angles in the 200-MeV rvec p+ nat Ag reaction. The observed analyzing powers are consistent with zero, and thus do not provide evidence for a significant contribution from cluster knockout, or similar direct formation mechanisms. Fragment kinetic-energy spectra above the Coulomb peak are compared with a coalescence calculation. The isotopic composition of the elemental kinetic-energy spectra is found to favor N/Z≥1 nuclei for fragment energies near the exit-channel Coulomb energy, whereas species with N/Z≤1 are more abundant in the high-energy spectral tails. This behavior is consistent with the predictions of an accreting source calculation

Modelling the Maillard reaction during the cooking of a model cheese.

Science.gov (United States)

Bertrand, Emmanuel; Meyer, Xuân-Mi; Machado-Maturana, Elizabeth; Berdagué, Jean-Louis; Kondjoyan, Alain

2015-10-01

During processing and storage of industrial processed cheese, odorous compounds are formed. Some of them are potentially unwanted for the flavour of the product. To reduce the appearance of these compounds, a methodological approach was employed. It consists of: (i) the identification of the key compounds or precursors responsible for the off-flavour observed, (ii) the monitoring of these markers during the heat treatments applied to the cheese medium, (iii) the establishment of an observable reaction scheme adapted from a literature survey to the compounds identified in the heated cheese medium (iv) the multi-responses stoichiokinetic modelling of these reaction markers. Systematic two-dimensional gas chromatography time-of-flight mass spectrometry was used for the semi-quantitation of trace compounds. Precursors were quantitated by high-performance liquid chromatography. The experimental data obtained were fitted to the model with 14 elementary linked reactions forming a multi-response observable reaction scheme. Copyright © 2015 Elsevier Ltd. All rights reserved.

Transport processes in exothermic gas-solid reactions

International Nuclear Information System (INIS)

Vijay, P.L.; Sathiyamoorthy, D.

1997-01-01

The variation of the concentration of gaseous reactant, temperature distribution for an exothermic reaction, the diffusivity factor and the reaction ratio profiles with various radial positions of a solid reactant have been computed and illustrated for a specific case of reduction reaction of UO 3 by hydrogen

Introducing Technology Education at the Elementary Level

Science.gov (United States)

McKnight, Sean

2012-01-01

Many school districts are seeing a need to introduce technology education to students at the elementary level. Pennsylvania's Penn Manor School District is one of them. Pennsylvania has updated science and technology standards for grades 3-8, and after several conversations the author had with elementary principals and the assistant superintendent…

Elementary School Teachers and Teaching with Technology

Science.gov (United States)

Varol, Filiz

2013-01-01

This study aims to identify the relationship between elementary school teachers' ICT engagement with their attitudes towards technology. To this end, one hundred elementary school students were asked to fill out questionnaires related to their ICT knowledge, usage, and attitude towards technology. The results show that teachers' ICT knowledge and…

A spectral study of the elementary step of proton transfer in heterogeneous acid catalysis

Energy Technology Data Exchange (ETDEWEB)

Kazanskii, V B

1977-09-01

A spectral study of the elementary step of proton transfer in heterogeneous acid catalysis involved a determination of the potential curves of the OH bond in surface hydroxyl groups (e.g., those on silica, NaHY zeolite, or glass) of differing acidity from IR stretching frequency data in the overtone region; a calculation of the activation energies for proton transfer during acid catalysis from the changes in the curve forms after adsorption of various molecules (e.g., water, ammonia, benzene, toluene, xylenes, acetone, and cyclohexane); and a comparison of the IR predictions with quantum-chemical calculations of the potential curves. The results appear to furnish a new criterion for the coordinate of reactions involving Broensted sites: if the activation energy measured during actual catalysis is close to that calculated from the IR stretching data, the reaction proceeds by the stepwise mechanism of acid catalysis; but if these values differ greatly, the reaction involves a concerted mechanism (i.e., activation of the adsorbed molecule without involvement of OH groups). Tables, graphs, and 15 references.

Multiple particles production for hadron-hadron reactions with finite hadronization time

International Nuclear Information System (INIS)

Arbex, N.

1991-01-01

Experimental data on multiple particle production for proton-proton reaction are analysed in the context of a very simple analytical model. The model exhibits the essential features of hydrodynamical calculations as, e.g., the formation of an intermediate object, which undergoes expansion. The simultaneous analysis of different types of data allows for the conclusion that such data reflect the dynamics of this intermediate object and have a very deem connection to the elementary processes. (author)

Reform in Turkish Elementary Mathematics Curriculum

OpenAIRE

BABADOĞAN, Cem; OLKUN, Sinan

2006-01-01

Disappointed from such major international studies as TIMSS, PISA, PIRLS andsome internal indicators such as national university entrance examination, the Turkish Ministry ofNational Education initiated a massive reform movement in education. These reforms includedeveloping new curricula for both elementary and secondary education and developing teachercompetencies. The purpose of this paper is to present an evaluation of the elementary schoolmathematics curriculum, which is a part of the ref...

Kinetics of the Br2-CH3CHO Photochemical Chain Reaction

Science.gov (United States)

Nicovich, J. M.; Shackelford, C. J.; Wine, P. H.

1997-01-01

Time-resolved resonance fluorescence spectroscopy was employed in conjunction with laser flash photolysis of Br2 to study the kinetics of the two elementary steps in the photochemical chain reaction nBr2 + nCH3CHO + hv yields nCH3CBrO + nHBr. In the temperature range 255-400 K, the rate coefficient for the reaction Br((sup 2)P(sub 3/2)) + CH3CHO yields CH3CO + HBr is given by the Arrhenius expression k(sub 6)(T) = (1.51 +/- 0.20) x 10(exp -11) exp(-(364 +/- 41)/T)cu cm/(molecule.s). At 298 K, the reaction CH3CO + Br2 yields CH3CBrO + Br proceeds at a near gas kinetic rate, k(sub 7)(298 K) = (1.08 +/- 0.38) x 10(exp -10)cu cm/(molecule.s).

Elementary Children's Retrodictive Reasoning about Earth Science

Science.gov (United States)

Libarkin, Julie C.; Schneps, Matthew H.

2012-01-01

We report on interviews conducted with twenty-one elementary school children (grades 1-5) about a number of Earth science concepts. These interviews were undertaken as part of a teacher training video series designed specifically to assist elementary teachers in learning essential ideas in Earth science. As such, children were interviewed about a…

3He/4He production ratios by tetrahedral symmetric condensation

International Nuclear Information System (INIS)

Takahashi, Akito

2006-01-01

The present paper treats application of the Electronic Quasi-Particle Expansion Theory (EQPET) model for Tetrahedral Symmetric Condensate (TSC) of H/D mixed systems for Pd host metal. Production ratios of 3 He/ 4 He for multi-body fusion reactions in H/D mixed TSC systems are calculated as a function of H/D mixing ratio. The model is further extended to treat direct nuclear interactions between host-metal nucleus and TSC of pure four protons (or four deuterons), since TSC can become very small (far less than 1 pm radius) charge-neutral pseudo-particle. Results for the case of Ni + 4p/TSC are discussed with Ni + p capture reactions and Ni + 4p fission reactions. (authors)

Recent (t,p) and (3He,n) studies of elementary excitations in the lead region

International Nuclear Information System (INIS)

Flynn, E.R.

1978-01-01

A number of experiments involving two-nucleon transfer reactions were recently carried out in the region of 208 Pb to explore the limits of the pairing vibration model. ( 3 He,n) studies revealed that the proton pairing elementary excitations give a reasonably simple vibrational picture after corrections for important particle--hole terms. These data are also described accurately by microscopic calculations of the 0 + pairing phonon. (t,p) results on a 204 Hg target reveal a pairing vibrational state in 206 Hg near the predicted energy, after various interactions are taken into account. 14 figures

Measurement of excitation functions and isomeric ratios of the reactions 103Rh(3He, xn) sup(106-x)Ag where x=2, 3 and 4

International Nuclear Information System (INIS)

Borges, A.M.

1981-01-01

The excitation functions and isomer ratios for the reactions 103 Rh( 3 He, xn) sup(106-x)Ag, where x=2, 3 and 4, were measured with projectile Lab energy varying from 23 to 35 MeV. Since the half-life of sup(103m)Ag is equal to 5.7 s. the use of a recoil nucleous gas jet transport system became necessary. The values measured for the cross-sections were compared to those yielded by the ALICE code. The experimental isomer ratios are smaller than those calculated using the residual nucleus spin distribution obtained with the ALICE code. By-pass fractions as expected in this mass region were also obtained. (Author) [pt

Crossed-beam studies of the dynamics of radical reactions

Energy Technology Data Exchange (ETDEWEB)

Liu, K. [Argonne National Laboratory, IL (United States)

1993-12-01

The objective of this program is to characterize the detailed dynamics of elementary radical reactions and to provide a better understanding of radical reactivity in general. The radical beam is typically generated by a laser photolysis method. After colliding with the reacting molecule in a crossed-beam apparatus, the reaction product state distribution is interrogated by laser spectroscopic techniques. Several radicals of combustion significance, such as O, CH, OH, CN and NCO have been successfully generated and their collisional behavior at the state-to-state integral cross section level of detail has been studied in this manner. During the past year, the detection system has been converted from LIF to REMPI schemes, and the emphasis of this program shifted to investigate the product angular distributions. Both inelastic and reactive processes have been studied.

A model for evaluating the environmental benefits of elementary school facilities.

Science.gov (United States)

Ji, Changyoon; Hong, Taehoon; Jeong, Kwangbok; Leigh, Seung-Bok

2014-01-01

In this study, a model that is capable of evaluating the environmental benefits of a new elementary school facility was developed. The model is composed of three steps: (i) retrieval of elementary school facilities having similar characteristics as the new elementary school facility using case-based reasoning; (ii) creation of energy consumption and material data for the benchmark elementary school facility using the retrieved similar elementary school facilities; and (iii) evaluation of the environmental benefits of the new elementary school facility by assessing and comparing the environmental impact of the new and created benchmark elementary school facility using life cycle assessment. The developed model can present the environmental benefits of a new elementary school facility in terms of monetary values using Environmental Priority Strategy 2000, a damage-oriented life cycle impact assessment method. The developed model can be used for the following: (i) as criteria for a green-building rating system; (ii) as criteria for setting the support plan and size, such as the government's incentives for promoting green-building projects; and (iii) as criteria for determining the feasibility of green building projects in key business sectors. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sleep Habits of Elementary and Middle School Children in South Texas.

Science.gov (United States)

Surani, Salim; Hesselbacher, Sean; Surani, Saherish; Sadasiva, Sreevidya; Surani, Zoya; Surani, Sara S; Khimani, Amina; Subramanian, Shyam

2015-01-01

Background. Sleep difficulties, including insufficient sleep and inadequate sleep hygiene, have been prevalent among children. Sleep deprivation can lead to poor grades, sleepiness, and moodiness. We undertook this study to assess the prevalence of sleep abnormalities among elementary and middle school students in South Texas and how the groups compare with one another. Method. After approval from the appropriate school district for a sleep education program, a baseline survey was taken of elementary and middle school students, using the Children's Sleep Habit Questionnaire-Sleep Self-Report Form, which assessed the domains of bedtime resistance, sleep onset delay, sleep anxiety, sleep duration, night awakening, and daytime sleepiness. Results. The survey was completed by 499 elementary and 1008 middle school children. Trouble sleeping was reported by 43% in elementary school, compared with 29% of middle school children. Fifty percent of middle school children did not like sleeping, compared with 26% in elementary school. Bedtime resistance, sleep onset delay, and nighttime awakening were more common among elementary school students. Daytime sleepiness was more common among the middle school children when compared to elementary school children. Conclusions. Sleep abnormalities are present in elementary school children with changes in sleep habits into middle school.

Investigating the Self-Perceived Science Teaching Needs of Local Elementary Educators

Science.gov (United States)

Carver, Cynthia G.

Elementary teachers in one school system have expressed low self-efficacy teaching science and desire more support teaching science. However, little research has been conducted on how best to meet these teachers' needs. The theories of perceived self-efficacy, social cognition, and behaviorism make up the conceptual framework of this study. The focus of this qualitative project study was on the needs of local elementary educators. These teachers were asked what they felt they needed most to be more effective science educators. The methodology of phenomenology was used in this study in which local elementary teachers were questioned in focus groups regarding their own science teaching efficacy and perceived needs. Using inductive analysis, data were coded for links to discussion questions as well as any additional patterns that emerged. Findings indicated that local elementary teachers desire improved communication among administrators and teachers as well as better science content support and training. Focus group participants agreed that teacher self-efficacy affects the time spent, effort toward, and quality of elementary science education. Using the results of the study, a science mentor program was developed to support the needs of elementary teachers and increase teacher self-efficacy, thus improving local elementary science education. Implications for positive social change include the development and support of elementary science programs in other school systems with the goal of improving science education for elementary students.

Progress in elementary particle theory, 1950-1964

International Nuclear Information System (INIS)

Gell-Mann, M.

1989-01-01

This final chapter of the book lists advances in elementary particle theory from 1950 to 1964 in an order of progressive understanding of ideas rather than chronologically. Starting with quantum field theory and the important discoveries within it, the author explains the connections and items missing in this decade, but understood later. The second part of the chapter takes the same pattern, but deals with basic interactions (strong, electromagnetic, weak and gravitational) and elementary particles, including quarks. By 1985, theory had developed to such a degree that it was hoped that the long-sought-after unified field theory of all elementary particles and interactions of nature might be close at hand. (UK)

Communication and Stakeholder Engagement at Brighouse Elementary

Science.gov (United States)

Drew, Robert

2011-01-01

The Samuel Brighouse Elementary School, located in Richmond, BC, a city adjacent to Vancouver on the west coast of Canada, is a five-hundred student elementary school. When completed in September 2011, it will replace an existing older school on the same site. This project was identified early on as an opportunity for the Richmond School Board to…

The general theory of multistage geminate reactions of isolated pairs of reactants. III. Two-stage reversible dissociation in geminate reaction A + A↔C↔B + B

Energy Technology Data Exchange (ETDEWEB)

Kipriyanov, Alexey A.; Kipriyanov, Alexander A.; Doktorov, Alexander B. [Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia and Novosibirsk State University, Novosibirsk 630090 (Russian Federation)

2016-04-14

Specific two-stage reversible reaction A + A↔C↔B + B of the decay of species C reactants by two independent transition channels is considered on the basis of the general theory of multistage reactions of isolated pairs of reactants. It is assumed that at the initial instant of time, the reacting system contains only reactants C. The employed general approach has made it possible to consider, in the general case, the inhomogeneous initial distribution of reactants, and avoid application of model concepts of a reaction system structure (i.e., of the structure of reactants and their molecular mobility). Slowing of multistage reaction kinetics as compared to the kinetics of elementary stages is established and physically interpreted. To test approximations (point approximation) used to develop a universal kinetic law, a widely employed specific model of spherical particles with isotropic reactivity diffusing in solution is applied. With this particular model as an example, ultimate kinetics of chemical conversion of reactants is investigated. The question concerning the depths of chemical transformation at which long-term asymptotes are reached is studied.

Elementary particles and particle interactions

International Nuclear Information System (INIS)

Bethge, K.; Schroeder, U.E.

1986-01-01

This book is a textbook for an introductory course of elementary particle physics. After a general introduction the symmetry principles governing the interactions of elementary particles are discussed. Then the phenomenology of the electroweak and strong interactions are described together with a short introduction to the Weinberg-Salam theory respectively to quantum chromodynamics. Finally a short outlook is given to grand unification with special regards to SU(5) and cosmology in the framework of the current understanding of the fundamental principles of nature. In the appendix is a table of particle properties and physical constants. (HSI) [de

Dispersion Theory of Direct Nuclear Reactions

Energy Technology Data Exchange (ETDEWEB)

Shapiro, I. S. [Institute Of Theoretical And Experimental Physics, Moscow, USSR (Russian Federation)

1963-01-15

applicability. The method referred to is known as dispersion theory or dispersion method. In the form used for the description of direct processes, the dispersion theory originated and developed in the physics of the strong interactions of elementary particles. The theory has replaced the Hamiltonian formalism of quantum field thecry and contributed to a substantial advance in the solution of some problems. The possibility of applying dispersion theory to the auantitative description of direct processes stems from the very structure of this theory in which any ''compound'' particle (a nucleus, for example) which actually exists in a free state is treated exactly as an ''elementary'' particle. It is significant that certain sequences of dispersion theory are manifested in the properties of direct reactions no doubt more saliently than in the physics of the strong interactions of elementary particles. The ''dispersion nature'' of direct processes ''sticks out'' of experimental data so obviously that to grasp the essence of the dispersion approach it is worthwhile enumerating briefly the basic facts of direct nuclear reactions. (author)

Dispersion Theory of Direct Nuclear Reactions

International Nuclear Information System (INIS)

Shapiro, I.S.

1963-01-01

applicability. The method referred to is known as dispersion theory or dispersion method. In the form used for the description of direct processes, the dispersion theory originated and developed in the physics of the strong interactions of elementary particles. The theory has replaced the Hamiltonian formalism of quantum field thecry and contributed to a substantial advance in the solution of some problems. The possibility of applying dispersion theory to the auantitative description of direct processes stems from the very structure of this theory in which any ''compound'' particle (a nucleus, for example) which actually exists in a free state is treated exactly as an ''elementary'' particle. It is significant that certain sequences of dispersion theory are manifested in the properties of direct reactions no doubt more saliently than in the physics of the strong interactions of elementary particles. The ''dispersion nature'' of direct processes ''sticks out'' of experimental data so obviously that to grasp the essence of the dispersion approach it is worthwhile enumerating briefly the basic facts of direct nuclear reactions. (author)

Measurement of glass transition temperature, residual heat of reaction and mixing ratio of epoxy resins using near infrared spectroscopy: a preliminary study

DEFF Research Database (Denmark)

Houmøller, Lars Plejdrup; Laursen, Peter Clemen

2003-01-01

As a measure of the degree of curing of epoxy resins, the glass transition temperature, Tg, and the residual heat of reaction, DeltaHr, are often used. In this study, near infrared spectroscopy and multivariate calibration (partial least squares regression (PLSR)) have been used to monitor the two...... variables, using differential scanning calorimetry (DSC) as the reference method. The epoxy under study was a commercial system consisting of the resin, trimethylolpropanetriglycidylether, and the hardener, 3-aminomethyl-3,5,5,-trimethylcyclohexylamine. Using samples cured under different conditions......, calibrations resulted in root mean square errors of cross-validation (RMSECV) of 18 J/g for DeltaHr (range for Hr: 6.1-231.3 J/g) and 7.2ºC for Tg (range for Tg: 41.5-98.8ºC). Also, a PLSR model for mixing ratio of hardener and resin was obtained, resulting in a RMSECV of 0.0040 (range for mixing ratio: 0.180-0.380)...

Elementary particles physics

International Nuclear Information System (INIS)

1990-01-01

It is discussed the physics in Brazil in the next decade with regard to elementary particles and field theories. The situation of brazilian research institutes as well as its personnel is also presented. Some recommendations and financing of new projects are also considered. (A.C.A.S.)

Sleep Habits of Elementary and Middle School Children in South Texas

Directory of Open Access Journals (Sweden)

Salim Surani

2015-01-01

Full Text Available Background. Sleep difficulties, including insufficient sleep and inadequate sleep hygiene, have been prevalent among children. Sleep deprivation can lead to poor grades, sleepiness, and moodiness. We undertook this study to assess the prevalence of sleep abnormalities among elementary and middle school students in South Texas and how the groups compare with one another. Method. After approval from the appropriate school district for a sleep education program, a baseline survey was taken of elementary and middle school students, using the Children’s Sleep Habit Questionnaire-Sleep Self-Report Form, which assessed the domains of bedtime resistance, sleep onset delay, sleep anxiety, sleep duration, night awakening, and daytime sleepiness. Results. The survey was completed by 499 elementary and 1008 middle school children. Trouble sleeping was reported by 43% in elementary school, compared with 29% of middle school children. Fifty percent of middle school children did not like sleeping, compared with 26% in elementary school. Bedtime resistance, sleep onset delay, and nighttime awakening were more common among elementary school students. Daytime sleepiness was more common among the middle school children when compared to elementary school children. Conclusions. Sleep abnormalities are present in elementary school children with changes in sleep habits into middle school.

Novel error propagation approach for reducing H2S/O2 reaction mechanism

International Nuclear Information System (INIS)

Selim, H.; Gupta, A.K.; Sassi, M.

2012-01-01

A reduction strategy of hydrogen sulfide/oxygen reaction mechanism is conducted to simplify the detailed mechanism. Direct relation graph and error propagation methodology (DRGEP) has been used. A novel approach of direct elementary reaction error (DERE) has been developed in this study. The developed approach allowed for further reduction of the reaction mechanism. The reduced mechanism has been compared with the detailed mechanism under different conditions to emphasize its validity. The results obtained from the resulting reduced mechanism showed good agreement with that from the detailed mechanism. However, some discrepancies have been found for some species. Hydrogen and oxygen mole fractions showed the largest discrepancy of all combustion products. The reduced mechanism was also found to be capable of tracking the changes that occur in chemical kinetics through the change in reaction conditions. A comparison on the ignition delay time obtained from the reduced mechanism and previous experimental data showed good agreement. The reduced mechanism was used to track changes in mechanistic pathways of Claus reactions with the reaction progress.

Serpentinization as a reactive transport process: The brucite silicification reaction

Science.gov (United States)

Tutolo, Benjamin M.; Luhmann, Andrew J.; Tosca, Nicholas J.; Seyfried, William E.

2018-02-01

Serpentinization plays a fundamental role in the biogeochemical and tectonic evolution of the Earth and perhaps many other rocky planetary bodies. Yet, geochemical models still fail to produce accurate predictions of the various modes of serpentinization, which limits our ability to predict a variety of related geological phenomena over many spatial and temporal scales. Here, we use kinetic and reactive transport experiments to parameterize the brucite silicification reaction and provide fundamental constraints on SiO2 transport during serpentinization. We show that, at temperatures characteristic of the sub-seafloor at the serpentinite-hosted Lost City Hydrothermal Field (150 °C), the assembly of Si tetrahedra onto MgOH2 (i.e., brucite) surfaces is a rate-limiting elementary reaction in the production of serpentine and/or talc from olivine. Moreover, this reaction is exponentially dependent on the activity of aqueous silica (a SiO2 (aq)), such that it can be calculated according to the rate law:

Elementary School Psychologists and Response to Intervention (RTI)

Science.gov (United States)

Little, Suzanne; Marrs, Heath; Bogue, Heidi

2017-01-01

The implementation of Response to Intervention (RTI) in elementary schools may have important implications for school psychologists. Therefore, it is important to better understand how elementary school psychologists perceive RTI and what barriers to successful RTI implementation they identify. Although previous research has investigated the…

Evaluation of excitation functions for isomeric levels in neutron reactions

International Nuclear Information System (INIS)

Grudzevich, O.T.; Zelenetskij, A.V.; Zolotarev, K.I.; Kornilov, N.V.; Pashchenko, A.B.

1993-07-01

The authors consider the use of theoretical models to describe experimental excitation functions for isomeric levels in neutron reactions and to predict the cross-sections when no experimental data are available. It is shown that, in many cases, experimental data can be described quite satisfactorily by calculations without adjustment of parameters. For threshold reactions at a neutron energy of ∼ 14 MeV the agreement between calculated and experimental isomeric ratios is ∼ 20%, and is determined mainly by errors in the experimental ratios. However, for some reactions there are considerable differences between experimental and calculated data, which are due, in the authors' opinion, to uncertainties in the schemes of the low-lying levels and of gamma transitions between levels and to the spin dependence of level density. The small isomeric ratio values R<0.1 are described with the lowest accuracy. A formula is suggested for the energy dependence of the isomeric ratio in the (n,γ) reaction. (author)

Ametryn degradation by aqueous chlorine: Kinetics and reaction influences

International Nuclear Information System (INIS)

Xu Bin; Gao Naiyun; Cheng Hefa; Hu Chenyan; Xia Shengji; Sun Xiaofeng; Wang Xuejiao; Yang Shaogui

2009-01-01

The chemical oxidation of the herbicide ametryn was investigated by aqueous chlorination between pH 4 and 10 at a temperature of 25 deg. C. Ametryn was found to react very rapidly with aqueous chlorine. The reaction kinetics can be well described by a second-order kinetic model. The apparent second-order rate constants are greater than 5 x 10 2 M -1 s -1 under acidic and neutral conditions. The reaction proceeds much more slowly under alkaline conditions. The predominant reactions were found to be the reactions of HOCl with neutral ametryn and the charged ametryn, with rate constants equal to 7.22 x 10 2 and 1.58 x 10 3 M -1 s -1 , respectively. The ametryn degradation rate increases with addition of bromide and decreases with addition of ammonia during the chlorination process. Based on elementary chemical reactions, a kinetic model of ametryn degradation by chlorination in the presence of bromide or ammonia ion was also developed. By employing this model, we estimate that the rate constants for the reactions of HOBr with neutral ametryn and charged ametryn were 9.07 x 10 3 and 3.54 x 10 6 M -1 s -1 , respectively. These values are 10- to 10 3 -fold higher than those of HOCl, suggesting that the presence of bromine species during chlorination could significantly accelerate ametryn degradation.

Olympiads for Elementary Schools.

Science.gov (United States)

Lenchner, George

1985-01-01

The goals and history of the Mathematical Olympiads for Elementary Schools are described. Teams, levels, and gender are discussed, as well as teacher training, administration, scoring, and awards. Sample problems are included. (MNS)

Laser Kinetic Spectroscopic Studies of (a) The Unimolecular Reactions of Nitroalkanes and, (b) Elementary Reactions Important in Combustion.

Science.gov (United States)

1981-08-31

4, and F. Reislor and C. Wittig, J. Che.:,. Phys. 69 (1978) 3729. 17. G. flerzborg, Molecular Spectra andri3 Iolcul ’r StrulCt e, Vol-. 1, Spe~ctra... emision from reaction (1) vs 02 pressure. C2 1" was gencr~ted by : C2 HCHO photolysis at 193 nm; /k C2! 2 photo~ysis at 193 ni; [J C2 fBr photolysis at

Is the Field of Numbers a Real Physical Field? On the Frequent Distribution and Masses of the Elementary Patricles

Directory of Open Access Journals (Sweden)

Belyakov A. V.

2010-07-01

Full Text Available Frequent distributions of the databases of the numerical values obtained by resolving algorithms, which describe physical and other processes, give a possibility for bonding the probability of that results the algorithms get. In the frequent distribution of the fractions of integers (rational numbers, local maxima which meet the ratios of masses of the elementary particles have been found.

Is the Field of Numbers a Real Physical Field? On the Frequent Distribution and Masses of the Elementary Particles

Directory of Open Access Journals (Sweden)

Belyakov A. V.

2010-04-01

Full Text Available Frequent distributions of the databases of the numerical values obtained by resolving algorithms, which describe physical and other processes, give a possibility for bonding the probability of that results the algorithms get. In the frequent distribution of the fractions of integers (rational numbers, local maxima which meet the ratios of masses of the elementary particles have been found.

Quantum Black Holes As Elementary Particles

OpenAIRE

Ha, Yuan K.

2008-01-01

Are black holes elementary particles? Are they fermions or bosons? We investigate the remarkable possibility that quantum black holes are the smallest and heaviest elementary particles. We are able to construct various fundamental quantum black holes: the spin-0, spin 1/2, spin-1, and the Planck-charge cases, using the results in general relativity. Quantum black holes in the neighborhood of the Galaxy could resolve the paradox posed by the Greisen-Zatsepin-Kuzmin limit on the energy of cosmi...

Reaction mechanism of reductive decomposition of FGD gypsum with anthracite

International Nuclear Information System (INIS)

Zheng, Da; Lu, Hailin; Sun, Xiuyun; Liu, Xiaodong; Han, Weiqing; Wang, Lianjun

2013-01-01

Highlights: • The reaction mechanism was different if the molar ratio of C/CaSO 4 was different. • The yield of CaO rises with an increase in temperature. • The optimal ratio of C/CaSO 4 = 1.2:1. • The decomposition process is mainly apparent solid–solid reaction with liquid-phase involved. - Abstract: The process of decomposition reaction between flue gas desulfurization (FGD) gypsum and anthracite is complex, which depends on the reaction conditions and atmosphere. In this study, thermogravimetric analysis with Fourier transform infrared spectroscopy (TGA-FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and the experiment in a tubular reactor were used to characterize the decomposition reaction in a nitrogen atmosphere under different conditions. The reaction mechanism analysis showed that the decomposition reaction process and mechanism were different when the molar proportion of C/CaSO 4 was changed. The experiment results showed that appropriate increase in the C/CaSO 4 proportion and higher temperatures were suitable for the formation of the main production of CaO, which can help us to understand the solid state reaction mechanism better. Via kinetic analysis of the reaction between anthracite and FGD gypsum under the optimal molar ratio of C/CaSO 4 , the mechanism model of the reaction was confirmed and the decomposition process was a two-step reaction which was in accordance with apparent solid–solid reaction

Non-Print Social Studies Materials--Elementary School Level.

Science.gov (United States)

Lynn, Karen

Types of non-print social studies materials developed for presentation to, and use by, elementary school students are identified. "Non-print" materials include films, filmstrips, video cassettes, audio recordings, computer databases, telecommunications, and hypertext. An explanation of why elementary school students can benefit from the use of…

Preparing Elementary Prospective Teachers to Teach Early Algebra

Science.gov (United States)

Hohensee, Charles

2017-01-01

Researchers have argued that integrating early algebra into elementary grades will better prepare students for algebra. However, currently little research exists to guide teacher preparation programs on how to prepare prospective elementary teachers to teach early algebra. This study examines the insights and challenges that prospective teachers…

Research project AUS-10370/CF: electron impact ionization and surface induced reactions of edge plasma constituents

International Nuclear Information System (INIS)

Maerk, T.D.

1999-01-01

In order to better understand elementary reactions which are taking place at the plasma edge of thermonuclear fusion devices, three areas of research were persuaded: I) Experimental studies about electron ionization of neutrals and ions and electron attachment to molecules, II) Theoretical studies about electron ionisation of neutrals and ions and III) Reactive interaction of molecular ions with surfaces

Elementary particle interactions

International Nuclear Information System (INIS)

Bugg, W.M.; Condo, G.T.; Handler, T.; Hart, E.L.; Ward, B.F.L.; Close, F.E.; Christophorou, L.G.

1990-10-01

This report discusses freon bubble chamber experiments exposed to μ + and neutrinos, photon-proton interactions; shower counter simulations; SLD detectors at the Stanford Linear Collider, and the detectors at the Superconducting Super Collider; elementary particle interactions; physical properties of dielectric materials used in High Energy Physics detectors; and Nuclear Physics

Studies of nuclear reaction at very low energies

International Nuclear Information System (INIS)

Cecil, F.E.

1992-01-01

The deuteron radiative capture reactions on 2 H, 6 Li and 10 B have been measured between center of mass energies of 20 and 140 keV. Of note is the observation that the gamma ray-to-charged particle branching ratio for the DD reaction appears independent of energy down to a center of mass energy of 20 keV, consistent with some and contrary to other theoretical models. We have investigated the ratio of the reactions D(d,p)T and D(d,n) 3 He down to c.m. energies of 3 keV and the ratio of the reactions 6Li(d,p) 7 Li and 6 LI(d,α) 4 He down to a c.m. energy of 19 keV. The DD reaction ratio is independent of energy while the (d,p) branch of the D- 6 Li evinces a significant enhancement at the lowest measured energies. We have continued our investigation of charged particle production from deuterium-metal systems at a modest level of activity. Noteworthy in this investigation is the observation of 3 MeV protons from deuteron beam loaded Ti and LiD targets subjected to extreme thermal disequilibria. Significant facility improvements were realized during the most recent contract period. Specifically the downstream magnetic analysis system proposed to eliminate beam induced contaminants has been installed and thoroughly tested. This improvement should allow the D(a,γ) 6 Li reaction to be measured in the coming contract period. A scattering chamber required for the measurement of the 7 Li( 3 He,p) 9 Be reaction has been designed, fabricated and installed on the accelerator. A CAMAC based charged particle identification system has been assembled also for use in our proposed measurement of the 7 Li( 3 He, p) 9 Be

A Research on the Impact of Internet Use in American Elementary School Libraries

Directory of Open Access Journals (Sweden)

Feng-Hsiung Hou

2003-03-01

Full Text Available The purpose of this research was to explore the impact of Internet use in American elementary school libraries operations and to find the best way for use Internet tools in elementary school libraries operations. This study may offer important information about the impact of Internet usage for elementary school library s operations. The research question was: Is the Internet usage having significant impact for organizational operations in the American elementary school libraries? This study employed survey research to conduct the research process. Research participants were 50 administrators in 50 elementary school libraries; Texas, U.S.A. Descriptive statistics was used to analyze the impact of Internet applied in the elementary school libraries. Results indicated that there was a significant impact of the Internet usage in American elementary school libraries operations. The author suggests that elementary school libraries organizational leaders need pay attention to the impact of Internet usage in their business and they also need plan how to utilize the Internet into their elementary school libraries in the future.

Derivation of electron density and temperature from (S II) and (O II) line intensity ratios

Energy Technology Data Exchange (ETDEWEB)

Canto, J; Meaburn, J; Theokas, A C [Manchester Univ. (UK). Dept of Astronomy; Elliott, K H [Anglo-Australian Observatory, Epping (Australia)

1980-12-01

Line intensity ratios for (S II) and (O II) due to collisional de-excitation are briefly discussed. Comparison is made between various reaction rate parameters presented by separate investigators. Included are observations of ratios obtained from the Orion nebula which experimentally confirm the reaction rates of Pradhan as best representing the observed distribution of these ratios. (O II) and (S II) contour plots are also presented, which allow effective electron temperatures and densities to be estimated from pairs of line ratios.

Decay rate ratios of Υ(5S)→B anti B reactions

International Nuclear Information System (INIS)

Hwang, Dae Sung; Son, Hyungsuk

2010-01-01

We calculate the decay rate ratios for OZI allowed decays of Υ(5S) to two B mesons by using the decay amplitudes which incorporate the wave function of the Υ(5S) state. We obtain the result that the branching ratio of the Υ(5S) decay to B s * anti B s * is much larger than the branching ratio to B s anti B s * or anti B s B s * , in good agreement with the recent experimental results of CLEO and BELLE. This agreement with the experimental results is made possible since the nodes of the Υ(5S) radial wave function induce the nodes of the decay amplitude. We find that the results for the Υ(5S) decays to B u (*) anti B u (*) or B d (*) anti B d (*) pairs are sensitive to the parameter values used for the potential between heavy quarks. (orig.)

Future Elementary School Teachers' Conceptual Change Concerning Photosynthesis

Science.gov (United States)

Ahopelto, Ilona; Mikkila-Erdmann, Mirjamaija; Anto, Erkki; Penttinen, Marjaana

2011-01-01

The purpose of this study was to examine conceptual change among future elementary school teachers while studying a scientific text concerning photosynthesis. Students' learning goals in relation to their learning outcomes were also examined. The participants were future elementary school teachers. The design consisted of pre- and post-tests. The…

Classical versus Computer Algebra Methods in Elementary Geometry

Science.gov (United States)

Pech, Pavel

2005-01-01

Computer algebra methods based on results of commutative algebra like Groebner bases of ideals and elimination of variables make it possible to solve complex, elementary and non elementary problems of geometry, which are difficult to solve using a classical approach. Computer algebra methods permit the proof of geometric theorems, automatic…

Safety Education in the Elementary School. Fastback 170.

Science.gov (United States)

Wayne, Joseph E.

This pamphlet deals with incorporating effective safety education programs into the elementary school curriculum. Covered in a discussion of the scope and nature of the safety problem are classes of accidents (motor vehicle, home, work, and public accidents) and causes of accidents. Various functions of safety education in elementary schools are…

Kinetic investigation of the chlorine reduction reaction on electrochemically oxidised ruthenium

International Nuclear Information System (INIS)

Thomassen, M.; Karlsen, C.; Borresen, B.; Tunold, R.

2006-01-01

The rate and mechanism of the electroreduction of chlorine on electrooxidised ruthenium has been investigated with focus on the effect of solution pH. Current/potential curves for the reduction process in solutions with constant chloride concentration of 1.0 mol dm -3 and varying H + concentration have been obtained with the use of the rotating disk electrode technique (RDE). It was found that the chlorine reduction rate is highly inhibited in solutions with high H + concentrations and that it can be satisfactorily described by the Erenburg mechanism, previously suggested for the chlorine evolution on RuO 2 and RTO. The expression of the kinetic current as a function of chlorine and H + concentration was obtained by solving the elementary rate equations of the kinetic mechanism. The kinetic constants obtained from the correlation of the kinetic current expression to the experimental data were used to simulate the dependence of the surface coverages and elementary reaction rates on overpotential

Generalized elementary functions

Czech Academy of Sciences Publication Activity Database

Monteiro, Giselle Antunes; Slavík, A.

2014-01-01

Roč. 411, č. 2 (2014), s. 838-852 ISSN 0022-247X Institutional support: RVO:67985840 Keywords : elementary functions * Kurzweil-Stieltjes integral * generalized linear ordinary differential equations * time scale calculus Subject RIV: BA - General Mathematics Impact factor: 1.120, year: 2014 http://www.sciencedirect.com/science/article/pii/S0022247X13009141

Effect of the SQ4R Technique on the Reading Comprehension of Elementary School 4th Grade Elementary School Students

Science.gov (United States)

Basar, Murat; Gürbüz, Mehmet

2017-01-01

The aim of this study is to examine the effect of SQ4R (Survey, Question, Read, Reflect, Recite, Review) technique of the reading comprehension ability of elementary school 4th grade students. The sampling was constituted by 57 students from two different branches of the Ataturk Elementary School in the center of Usak region during the 2nd…

The complex dynamics of wishful thinking: the critical positivity ratio.

Science.gov (United States)

Brown, Nicholas J L; Sokal, Alan D; Friedman, Harris L

2013-12-01

We examine critically the claims made by Fredrickson and Losada (2005) concerning the construct known as the "positivity ratio." We find no theoretical or empirical justification for the use of differential equations drawn from fluid dynamics, a subfield of physics, to describe changes in human emotions over time; furthermore, we demonstrate that the purported application of these equations contains numerous fundamental conceptual and mathematical errors. The lack of relevance of these equations and their incorrect application lead us to conclude that Fredrickson and Losada's claim to have demonstrated the existence of a critical minimum positivity ratio of 2.9013 is entirely unfounded. More generally, we urge future researchers to exercise caution in the use of advanced mathematical tools, such as nonlinear dynamics, and in particular to verify that the elementary conditions for their valid application have been met. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Alkaline solution/binder ratio as a determining factor in the alkaline activation of aluminosilicates

Energy Technology Data Exchange (ETDEWEB)

Ruiz-Santaquiteria, C., E-mail: ruiz.cs@ietcc.csic.es [Eduardo Torroja Institute (CSIC), c/Serrano Galvache, n Degree-Sign 4, 28033 Madrid (Spain); Skibsted, J. [Instrument Centre for Solid-State NMR Spectroscopy, Interdisciplinary Nanoscience Center (iNANO), Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Fernandez-Jimenez, A.; Palomo, A. [Eduardo Torroja Institute (CSIC), c/Serrano Galvache, n Degree-Sign 4, 28033 Madrid (Spain)

2012-09-15

This study investigates the effect of the alkaline solution/binder (S/B) ratio on the composition and nanostructure of the reaction products generated in the alkaline activation of aluminosilicates. The experiments used two mixtures of fly ash and dehydroxylated white clay and for each of these, varying proportions of the solution components. The alkali activator was an 8 M NaOH solution (with and without sodium silicate) used at three S/B ratios: 0.50, 0.75 and 1.25. The {sup 29}Si, {sup 27}Al MAS NMR and XRD characterisation of the reaction products reveal that for ratios nearest the value delivering suitable paste workability, the reaction-product composition and structure depend primarily on the nature and composition of the starting materials and the alkaline activator used. However, when an excess alkaline activator is present in the system, the reaction products tend to exhibit SiO{sub 2}/Al{sub 2}O{sub 3} ratios of approximately 1, irrespective of the composition of the starting binder or the alkaline activator.

Excitation functions and isomeric ratios for the isomeric pair sup(106m)Ag and sup(106g)Ag in the 107Ag (d,t) reaction

International Nuclear Information System (INIS)

Lalli, M.E.; Wasilevsky de Lammirato, C.; Herreros, O.R.; Nassiff, S.J.

1976-09-01

Excitation functions and isomeric cross section ratios have been measured for the 107 Ag (d,t), reaction in which the isomeric pair sup(106m/106g)Ag is produced. Thick-target yields have been determined for different irradiation times and as a function of deuteron energy. Stacked silver foils with aluminium foils as monitors were bombarded with deuterons up to 27 MeV and the activities of products measured with a calibrated Ge(Li) counter. (author) [es

The general theory of multistage geminate reactions of isolated pairs of reactants. III. Two-stage reversible dissociation in geminate reaction A + A ↔ C ↔ B + B.

Science.gov (United States)

Kipriyanov, Alexey A; Kipriyanov, Alexander A; Doktorov, Alexander B

2016-04-14

Specific two-stage reversible reaction A + A ↔ C ↔ B + B of the decay of species C reactants by two independent transition channels is considered on the basis of the general theory of multistage reactions of isolated pairs of reactants. It is assumed that at the initial instant of time, the reacting system contains only reactants C. The employed general approach has made it possible to consider, in the general case, the inhomogeneous initial distribution of reactants, and avoid application of model concepts of a reaction system structure (i.e., of the structure of reactants and their molecular mobility). Slowing of multistage reaction kinetics as compared to the kinetics of elementary stages is established and physically interpreted. To test approximations (point approximation) used to develop a universal kinetic law, a widely employed specific model of spherical particles with isotropic reactivity diffusing in solution is applied. With this particular model as an example, ultimate kinetics of chemical conversion of reactants is investigated. The question concerning the depths of chemical transformation at which long-term asymptotes are reached is studied.

Curricular Pillars in the Elementary General Music Classroom

Science.gov (United States)

Howell, Allen C.

2009-01-01

Karen, a veteran elementary general music teacher, was bewildered when she learned that none of her students remembered "Peter and the Wolf," a music lesson they have encountered in the past. Conscientious beginning elementary general music teachers like Karen may work diligently to plan instruction that will ensure that national, state, and local…

Resource Letter HEPP-1: History of elementary-particle physics

International Nuclear Information System (INIS)

Hovis, R.C.; Kragh, H.

1991-01-01

This Resource Letter provides a guide to literature on the history of modern elementary-particle physics. Histories that treat developments from the 1930s through the 1980s are focused on and a sampling is included of the historiography covering the period c. 1890--1930, the prehistory of elementary-particle physics as a discipline. Also included are collections of scientific papers, which might be especially valuable to individuals who wish to undertake historical research on particular scientists or subfields of elementary-particle physics. The introduction presents some statistical data and associated references for elementary-particle physics and surveys historiographical approaches and issues that are represented in historical accounts in the bibliography. All references are assigned a rating of E (Elementary), I (Intermediate), or A (Advanced) based on their technical or conceptual difficulty or their appropriateness for a person attempting a graduated study of the history of modern particle physics. That is, items labeled E are suitable for the layman or would be fundamental to a beginning exploration of the history of particle physics, whereas items labeled A are technically demanding (mathematically, historiographically, or philosophically) or would be most appropriate for specialized or advanced examinations of various topics

Recent advances in elementary particle physics

International Nuclear Information System (INIS)

Zepeda, D.A.

1985-01-01

A brief review of recent successful results in elementary particle physics, as well as of those problems which may be dealt with in the present of near future is presented. A description of elementary particles and their interactions as they are presently conceived is given. The standard model of electroweak interactions is discussed in detail and the relevance of the recent discovery of the intermediate bosons W + and Z is analized. Finally, the weak features of the standard model and the theories which solve these problems are pointed out. (author)

Synthesis of multivalued quantum logic circuits by elementary gates

Science.gov (United States)

Di, Yao-Min; Wei, Hai-Rui

2013-01-01

We propose the generalized controlled X (gcx) gate as the two-qudit elementary gate, and based on Cartan decomposition, we also give the one-qudit elementary gates. Then we discuss the physical implementation of these elementary gates and show that it is feasible with current technology. With these elementary gates many important qudit quantum gates can be synthesized conveniently. We provide efficient methods for the synthesis of various kinds of controlled qudit gates and greatly simplify the synthesis of existing generic multi-valued quantum circuits. Moreover, we generalize the quantum Shannon decomposition (QSD), the most powerful technique for the synthesis of generic qubit circuits, to the qudit case. A comparison of ququart (d=4) circuits and qubit circuits reveals that using ququart circuits may have an advantage over the qubit circuits in the synthesis of quantum circuits.

Nonlinear reaction-diffusion equations with delay: some theorems, test problems, exact and numerical solutions

Science.gov (United States)

Polyanin, A. D.; Sorokin, V. G.

2017-12-01

The paper deals with nonlinear reaction-diffusion equations with one or several delays. We formulate theorems that allow constructing exact solutions for some classes of these equations, which depend on several arbitrary functions. Examples of application of these theorems for obtaining new exact solutions in elementary functions are provided. We state basic principles of construction, selection, and use of test problems for nonlinear partial differential equations with delay. Some test problems which can be suitable for estimating accuracy of approximate analytical and numerical methods of solving reaction-diffusion equations with delay are presented. Some examples of numerical solutions of nonlinear test problems with delay are considered.

Characteristics of headaches in Japanese elementary and junior high school students: A school-based questionnaire survey.

Science.gov (United States)

Goto, Masahide; Yokoyama, Koji; Nozaki, Yasuyuki; Itoh, Koichi; Kawamata, Ryou; Matsumoto, Shizuko; Yamagata, Takanori

2017-10-01

Few studies have investigated pediatric headaches in Japan. Thus, we examined the lifetime prevalence and characteristics of headaches among elementary and junior high school students in Japan. In this school-based study, children aged 6-15years completed a questionnaire based on the diagnostic criteria of the International Classification of Headache Disorders-3β to assess headache characteristics and related disability. Of the 3285 respondents, 1623 (49.4%) experienced headaches. Migraine and tension-type headaches (TTH) were reported by 3.5% and 5.4% of elementary school students, respectively, and by 5.0% and 11.2% of junior high school students. Primary headaches increased with age. Compared with TTH sufferers, the dominant triggers in migraine sufferers were hunger (odds ratio=4.7), sunny weather (3.3), and katakori (neck and shoulder pain) (2.5). Compared with TTH, migraine caused higher headache-related frustration (P=0.010) as well as difficulty concentrating (P=0.017). Migraine-related disability was greater among junior high school students (feeling fed up or irritated, P=0.028; difficulty concentrating, P=0.016). TTH-related disability was also greater among junior high school students (feeling fed up or irritated, P=0.035). Approximately half of the students who complained of headache-related disability were not receiving medical treatment. This is the first detailed study of headaches in Japanese children to include elementary school students. Nearly 50% of the school children reported headaches and the disruption of daily activities caused by migraine was higher among junior high students than elementary school students. Copyright © 2017 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Mechanism of tellurium isomers excitation in (γ, n) reactions

International Nuclear Information System (INIS)

Mazur, V.M.; Symochko, D.M.; Bigan, Z.M.; Poltorzhytska, T.V.; Derechkey, P.S.

2012-01-01

Isomeric yield ratios for the 119 Te, 121 Te, 123 Te, 127 Te, 129 Te nuclei were obtained in (γ, n) reactions with bremsstrahlung end point energies ranging 10 - 22 MeV with δE = 0.5 MeV step. Experimental isomeric ratios were used to calculate the cross-sections of (γ, n) m reactions, that were further compared with TALYS-1.4 calculations

Respirable antimony and other trace-elements inside and outside an elementary school in Flagstaff, AZ, USA

International Nuclear Information System (INIS)

Majestic, Brian J.; Turner, Joseph A.; Marcotte, Aurelie R.

2012-01-01

Because people spend almost 90% of their time indoors, ambient air monitors may severely underestimate actual exposure to atmospheric particulate matter (PM). Therefore, it becomes increasingly important to better understand the microenvironments where people are spending their time. For preadolescent children, the best estimates of exposure may be inside of their school. In this study, 11 size fractions of PM were collected inside and outside of an elementary school in Flagstaff, AZ, USA. In particles −3 — greater than many urban areas around the world. Cu:Sb ratios and size distribution functions suggest that the excess source of PM1 indoor Sb results from the suspension of embedded Sb (used as a flame retardant) in the carpeting. This is the first study to observe elevated submicron Sb in schools and further studies are required to determine if this is a widespread health risk. -- Highlights: ► Atmospheric particulate matter (PM) was collected inside and outside an elementary school. ► Size-resolved trace metal and mass concentrations were measured. ► Indoor / Outdoor ratios of PM mass were very large for particles larger than 1 µm and about unity for particles < 1 µm. ► Most of the metal mass was found to originate from crustal sources. ► Highly elevated levels of antimony were measured – most likely from the resuspension of Sb embedded in carpeting.

Upper Elementary Grades Bear the Brunt of Accountability

Science.gov (United States)

Anderson, Lorin W.

2009-01-01

Upper elementary teachers won't be surprised to learn that in every state, students enrolled in grades 3 through 8 bear the brunt of educational accountability. All states test all students at these grade levels in English/language arts and mathematics. Furthermore, an increasing number of states are testing students at selected elementary and…

Dimensional considerations about elementary particles

International Nuclear Information System (INIS)

Cocconi, G.

1978-01-01

The search for fundamental elementary particles responsible for the observed behaviour of matter during the past decades is briefly reviewed, and the possibility is considered that the four fundamental interactions that shape things merge into a unique field when matter is so compressed that particles are at extremely small distances from one another. These interactions are the gravitational interaction, the electromagnetic interaction, the strong interaction, and the weak interaction. It is thought that a simple geometrical criterion, termed the 'elementary criterion', would suffice to indicate how the various interactions should behave as particles are brought closer to one another and thus approach the situation where all interactions merge. (6 references). (U.K.)

INITIATIVES AND SUGGESTIONS FOR INTRODUCTION OF GYMNASTICS IN ELEMENTARY SCHOOLS OF THE PRINCIPALITY OF SERBIA (elementary schools, gymnastics, initiatives, suggestions, introduction

Directory of Open Access Journals (Sweden)

Slađana Mijatović

2006-06-01

Full Text Available Upon gaining its autonomy in 1830, the Principality of Serbia also creates the conditions for faster development of education, since the Sultan’s edict granted it the right to open schools. The first Law on schools was passed at the suggestion of the Head of the Ministry of Education Jovan Sterija Popovic in 1844 (Ustrojenije javnog učilištnog nastavlenija, and predicted a complete organization of all schools: elementary, commercial, high and lycees. The Law also prescribed three years of elementary education in villages and four years in towns. For the first time education of female children is predicted“Law on structure of elementary schools” was passed in September 1863 and it predicted the introduction of the fourth grade in village schools. Thirty-eight years (1830-1868 passed from obtaining autonomy, i.e. the right in Serbia to open its schools, to the official introduction of the physical activity instruction in elementary schools. It was a period in which it was attempted to organize structure and work of elementary schools. However physical education used to appear in pedagogic literature, drafts of laws on schools and proposals of officials and schools commissions of the Ministry of Education of the Principality of Serbia: 1. Milovan Spasic had hold an office of the main school principal since 1845 and he wrote three books, as the main reference books for elementary school teachers. One of them is “Pedagogično metodično nastavlenije ya učitelje osnovnih škola” (1855 where he wrote about physical education of children. Although physical education was not present in the Curriculum, he treated it as the most important task of both teachers and parents. 2. In the “Projekt zakona o školama za Knjažestvo Srbije” (1859 where you can find the subjects to be taught in elementary schools, it was stated that “as on of the subjects for boys ‘physical practice’ and ‘gymnastics’ for girls should be taught.” 3

Analysis of reaction schemes using maximum rates of constituent steps

Science.gov (United States)

Motagamwala, Ali Hussain; Dumesic, James A.

2016-01-01

We show that the steady-state kinetics of a chemical reaction can be analyzed analytically in terms of proposed reaction schemes composed of series of steps with stoichiometric numbers equal to unity by calculating the maximum rates of the constituent steps, rmax,i, assuming that all of the remaining steps are quasi-equilibrated. Analytical expressions can be derived in terms of rmax,i to calculate degrees of rate control for each step to determine the extent to which each step controls the rate of the overall stoichiometric reaction. The values of rmax,i can be used to predict the rate of the overall stoichiometric reaction, making it possible to estimate the observed reaction kinetics. This approach can be used for catalytic reactions to identify transition states and adsorbed species that are important in controlling catalyst performance, such that detailed calculations using electronic structure calculations (e.g., density functional theory) can be carried out for these species, whereas more approximate methods (e.g., scaling relations) are used for the remaining species. This approach to assess the feasibility of proposed reaction schemes is exact for reaction schemes where the stoichiometric coefficients of the constituent steps are equal to unity and the most abundant adsorbed species are in quasi-equilibrium with the gas phase and can be used in an approximate manner to probe the performance of more general reaction schemes, followed by more detailed analyses using full microkinetic models to determine the surface coverages by adsorbed species and the degrees of rate control of the elementary steps. PMID:27162366

Can Elementary Students Gather Information from Concept Maps?

Science.gov (United States)

Marulcu, Ismail; Karakuyu, Yunus; Dogan, Mevlut

2013-01-01

In this study, we investigated whether concept maps were used as often and as effectively in elementary science and technology classrooms as recommended by the National Ministry of Education (MEB) in the new curricula in Turkey. In the new elementary science and technology curricula, the MEB provides a general concept map for each unit. We used…

System Thinking Skills at the Elementary School Level

Science.gov (United States)

Assaraf, Orit Ben-Zvi; Orion, Nir

2010-01-01

This study deals with the development of system thinking skills at the elementary school level. It addresses the question of whether elementary school students can deal with complex systems. The sample included 40 4th grade students from one school in a small town in Israel. The students studied an inquiry-based earth systems curriculum that…

Elementary Algebra + Student-Written Web Illustrations = Math Mastery.

Science.gov (United States)

Veteto, Bette R.

This project focuses on the construction and use of a student-made elementary algebra tutorial World Wide Web page at the University of Memphis (Tennessee), how this helps students further explore the topics studied in elementary algebra, and how students can publish their work on the class Web page for use by other students. Practical,…

Prospects in the study of very inelastic electronuclear reactions

International Nuclear Information System (INIS)

Laget, J.M.

1983-03-01

Nuclear physics has reached a frontier where it is not possible to consider the classical constituents (mesons and nucleons) as inert objects: it is necessary to take also into account internal structure. After having shown how the study of nuclei, with the electromagnetic probe, has made it possible to solve and clarify some problems, it is shown under what conditions these internal degrees of freedom can show up in the study of electronuclear reactions, and to what extent the study of complex hadronic systems at short distance is an essential complement to the study of high momentum scattering between elementary hadrons

Teaching science as argument: Prospective elementary teachers' knowledge

Science.gov (United States)

Barreto-Espino, Reizelie

For the past two decades there has been increasing emphasis on argumentation in school science. In 2007, the National Research Council published a synthesis report that emphasizes the centrality of constructing, evaluating, and using scientific explanations. Participating in argumentation is seen as fundamental to children's science learning experiences. These new expectations increase challenges for elementary teachers since their understanding of and experiences with science are overwhelmingly inconsistent with teaching science as argument. These challenges are further amplified when dealing with prospective elementary teachers. The current study was guided by the following research questions: (1) What are the ways in which preservice elementary teachers appropriate components of "teaching science as argument" during their student teaching experience? (2) To what extent do components from prospective elementary teachers' reflections influence planning for science teaching? (3) What elements from the context influence preservice elementary teachers' attention to teaching science as argument? This study followed a multi-participant case study approach and analyses were informed by grounded theory. Three participants were selected from a larger cohort of prospective elementary teachers enrolled in an innovative Elementary Professional Development School (PDS) partnership at a large Northeast University. Cross-case analysis allowed for the development of five key assertions: (1) The presence of opportunities for interacting with phenomena and collecting first hand data helped participants increase their emphasis on evidence-based explanations. (2) Participants viewed science talks as an essential mechanism for engaging students in the construction of evidence-based explanations and as being fundamental to meaning-making. (3) Participants demonstrated attention to scientific subject matter during instruction rather than merely focusing on activities and/or inquiry

Imaging chemical reactions - 3D velocity mapping

Science.gov (United States)

Chichinin, A. I.; Gericke, K.-H.; Kauczok, S.; Maul, C.

Visualising a collision between an atom or a molecule or a photodissociation (half-collision) of a molecule on a single particle and single quantum level is like watching the collision of billiard balls on a pool table: Molecular beams or monoenergetic photodissociation products provide the colliding reactants at controlled velocity before the reaction products velocity is imaged directly with an elaborate camera system, where one should keep in mind that velocity is, in general, a three-dimensional (3D) vectorial property which combines scattering angles and speed. If the processes under study have no cylindrical symmetry, then only this 3D product velocity vector contains the full information of the elementary process under study.

Vision in elementary mathematics

CERN Document Server

Sawyer, W W

2003-01-01

Sure-fire techniques of visualizing, dramatizing, and analyzing numbers promise to attract and retain students' attention and understanding. Topics include basic multiplication and division, algebra, word problems, graphs, negative numbers, fractions, many other practical applications of elementary mathematics. 1964 ed. Answers to Problems.

Piaget and Elementary Science

Science.gov (United States)

Chittenden, Edward A.

1970-01-01

Describes the intellectual development stages ascribed to children by Jean Piaget. Characteristics and examples are given for sensori-motor, preoperational, concrete operational, and formal operational thinking periods. Implications are given for elementary school science education, including (1) formal instruction does not accelerate acquisition…

Elementary particles and cosmology

International Nuclear Information System (INIS)

Audouze, J.; Paty, M.

2000-01-01

The universe is the most efficient laboratory of particle physics and the understanding of cosmological processes implies the knowledge of how elementary particles interact. This article recalls the mutual influences between on the one hand: astrophysics and cosmology and on the other hand: nuclear physics and particle physics. The big-bang theory relies on nuclear physics to explain the successive stages of nucleo-synthesis and the study of solar neutrinos has led to discover new aspects of this particle: it is likely that neutrinos undergo oscillations from one neutrino type to another. In some universe events such as the bursting of a super-nova, particles are released with a kinetic energy that would be impossible to reach on earth with a particle accelerator. These events are become common points of interest between astrophysicists and particle physicists and have promoted a deeper cooperation between astrophysics and elementary particle physics. (A.C.)

A combined reaction class approach with integrated molecular orbital+molecular orbital (IMOMO) methodology: A practical tool for kinetic modeling

International Nuclear Information System (INIS)

Truong, Thanh N.; Maity, Dilip K.; Truong, Thanh-Thai T.

2000-01-01

We present a new practical computational methodology for predicting thermal rate constants of reactions involving large molecules or a large number of elementary reactions in the same class. This methodology combines the integrated molecular orbital+molecular orbital (IMOMO) approach with our recently proposed reaction class models for tunneling. With the new methodology, we show that it is possible to significantly reduce the computational cost by several orders of magnitude while compromising the accuracy in the predicted rate constants by less than 40% over a wide range of temperatures. Another important result is that the computational cost increases only slightly as the system size increases. (c) 2000 American Institute of Physics

Do Elementary Science Methods Textbooks Promote Understanding of Shadows?

Directory of Open Access Journals (Sweden)

Lloyd H. Barrow

2016-02-01

Full Text Available Elementary science methods textbooks can be an important resource for future elementary teachers of science. Since shadows are a common topic in elementary school and Next Generation Science Standards (NGSS Lead States, 2013. A series of ten shadows concepts were formed into a learning progression by Wizman and Fortus (2007. For this research, ten science methods textbook were read and analyzed about how each of the shadow concepts were addressed. These methods textbooks focused on a limited number of shadow concepts. Consequently, as a future reference, they are very limited in addressing all ten shadow concepts.

On the Origin of Elementary Particle Masses

OpenAIRE

Hansson, Johan

2012-01-01

The oldest enigma in fundamental particle physics is: Where do the observed masses of elementary particles come from? Inspired by observation of the empirical particle mass spectrum we propose that the masses of elementary parti cles arise solely due to the self-interaction of the fields associated with a particle. We thus assume that the mass is proportional to the strength of the interaction of th e field with itself. A simple application of this idea to the fermi...

Perceptions of Elementary Teachers on the Instructional Leadership Role of School Principals

Science.gov (United States)

Yavuz, Mustafa; Bas, Gokhan

2010-01-01

In this research, elementary school principals' instructional leadership behavior was evaluated based on the perceptions of elementary school teachers. The research is believed to contribute to the development of instructional leadership behavior of elementary school principals for the development of school organization. A "semi-structured…

Kinetics of selected elementary reactions of NH(a{sup 1}{delta}) or ND(a{sup {delta}}), NH(X{sup 3}{sigma}{sup -}) or ND(X{sup 3}{sigma}{sup -}) and NH{sub 2}(X), NHD(X), NH{sub 2}(X) radicals; Untersuchung der Kinetik ausgewaehlter Elementarreaktionen von NH(a{sup 1}{delta})- bzw. ND(a{sup 1}{delta})-, NH(X{sup 3}{sigma}{sup -})- bzw. ND(X{sup 3}{sigma}{sup -})- und NH{sub 2}(X)-, NHD(X)-, ND{sub 2}(X)-Radikalen

Energy Technology Data Exchange (ETDEWEB)

Adam, L.

2002-02-01

The elementary reactions of the NH and ND radicals in the ground state and the first excited state with H({sup 2}S) atoms and with molecules containing hydrogen and fluorine element bonds were investigated in the gaseous phase at a pressure of p = 7-80 bar. The elementary reactions of the NH{sub 2}, NHD and ND{sub 2} radicals in the ground state with hydrogen halides in the gaseous phase were investigated as well. [German] Die Elementarreaktionen des NH- bzw. ND-Radikals im Elektronengrundzustand und im ersten elektronisch angeregten Zustand mit H({sup 2}S)-Atomen und mit Molekuelen, die Wasserstoff- und Fluor-Elementbindungen besitzen, wurden in der Gasphase bei einem Druck von p = 7 - 80 mbar untersucht. Weiterhin wurden die Elementarreaktionen der NH{sub 2}-, NHD- bzw. ND{sub 2}-Radikale im Elektronengrundzustand mit Halogenwasserstoffen in der Gasphase untersucht. (orig.)

Combined influence of media use on subjective health in elementary school children in Japan: a population-based study.

Science.gov (United States)

Nakamura, Harunobu; Ohara, Kumiko; Kouda, Katsuyasu; Fujita, Yuki; Mase, Tomoki; Miyawaki, Chiemi; Okita, Yoshimitsu; Ishikawa, Tetsuya

2012-06-13

In recent years in Japan, electronic games, home computers, and the internet have assumed an important place in people's lives, even for elementary school children. Subjective health complaints have also become a problem among children. In the present study, we investigated the relationship between media use and health status in elementary school children in Japan. A cross-sectional school-based population survey was conducted in 2009 with a sample of fourth-, fifth-, and sixth-grade children (age range: 10-12 years old) in elementary schools in Japan (n = 3,464). Self-reported health, lifestyle habits, and time spent using media were assessed. The use of games, television, and personal computers was significantly associated with lifestyle (p media used for more than 1 hour was, the higher the odds ratio of the association of media use with unhealthy lifestyle and subjective health complaints was. The plural use of these media had stronger associations with unhealthy lifestyle and subjective health complaints. Game, television, and personal-computer use were mutually associated, and the plural use of these media had stronger associations with unhealthy lifestyle and subjective health complaints. Excessive use of media might be a risk for unhealthy lifestyle and subjective health complaints.

Earlier school start times are associated with higher rates of behavioral problems in elementary schools.

Science.gov (United States)

Keller, Peggy S; Gilbert, Lauren R; Haak, Eric A; Bi, Shuang; Smith, Olivia A

2017-04-01

Early school start times may curtail children's sleep and inadvertently promote sleep restriction. The current study examines the potential implications for early school start times for behavioral problems in public elementary schools (student ages 5-12 years) in Kentucky. School start times were obtained from school Web sites or by calling school offices; behavioral and disciplinary problems, along with demographic information about schools, were obtained from the Kentucky Department of Education. Estimated associations controlled for teacher/student ratio, racial composition, school rank, enrollment, and Appalachian location. Associations between early school start time and greater behavioral problems (harassment, in-school removals, suspensions, and expulsions) were observed, although some of these associations were found only for schools serving the non-Appalachian region. Findings support the growing body of research showing that early school start times may contribute to student problems, and extend this research through a large-scale examination of elementary schools, behavioral outcomes, and potential moderators of risk. Copyright © 2017 National Sleep Foundation. Published by Elsevier Inc. All rights reserved.

Education for Autonomy: The Role of Religious Elementary Schools

Science.gov (United States)

Macmullen, Ian

2004-01-01

I argue that religious elementary schools whose pedagogical methods satisfy the principle of rational authority have distinctive advantages over secular elementary schools for the purpose of laying the foundations for ethical autonomy in the children of religious parents. Insights from developmental psychology bolster the argument from conceptual…

Study of (n,2n reaction on 191,193Ir isotopes and isomeric cross section ratios

Directory of Open Access Journals (Sweden)

Vlastou R.

2017-01-01

Full Text Available The cross section of 191Ir(n,2n190Irg+m1 and 191Ir(n,2n190Irm2 reactions has been measured at 17.1 and 20.9 MeV neutron energies at the 5.5 MV tandem T11/25 Accelerator Laboratory of NCSR “Demokritos”, using the activation method. The neutron beams were produced by means of the 3H(d,n4He reaction at a flux of the order of 2 × 105 n/cm2s. The neutron flux has been deduced implementing the 27Al(n,α reaction, while the flux variation of the neutron beam was monitored by using a BF3 detector. The 193Ir(n,2n192Ir reaction cross section has also been determined, taking into account the contribution from the contaminant 191Ir(n,γ192Ir reaction. The correction method is based on the existing data in ENDF for the contaminant reaction, convoluted with the neutron spectra which have been extensively studied by means of simulations using the NeusDesc and MCNP codes. Statistical model calculations using the code EMPIRE 3.2.2 and taking into account pre-equilibrium emission, have been performed on the data measured in this work as well as on data reported in literature.

Observations on English education in elementary schools

OpenAIRE

カドゥアー, ドナルド; 藤澤, 良行; カドゥアー, ドナルド; フジサワ, ヨシユキ; Donald, KADUHR; Yoshiyuki, FUJISAWA

2009-01-01

This paper examines English-language teaching in the People's Republic of China through visitations to some elementary school grades in two large urban centres, Beijing and Dalian, in March 2008. Observations of English classes in China for students in grades 1 to 6, provide the basis of what we feel needs to be addressed for the implementation of English-language teaching in lower levels of Japanese elementary schools (grade 5 and above) from 2011. After giving a brief overview of the develo...

Describing Pre-Service Teachers' Developing Understanding of Elementary Number Theory Topics

Science.gov (United States)

Feldman, Ziv

2012-01-01

Although elementary number theory topics are closely linked to foundational topics in number and operations and are prevalent in elementary and middle grades mathematics curricula, little is currently known about how students and teachers make sense of them. This study investigated pre-service elementary teachers' developing understanding of…

ABC Problem in Elementary Mathematics Education: Arithmetic "before" Comprehension

Science.gov (United States)

Boote, Stacy K.; Boote, David N.

2018-01-01

Mathematical habits of prospective teachers affect problem comprehension and success and expose their beliefs about mathematics. Prospective elementary teachers (PSTs) (n = 121) engaged in a problem solving activity each week in class. Data were collected from PSTs enrolled in an undergraduate elementary mathematics methods course at a…

Cypriot Urban Elementary Students' Attitude toward Physical Education

Science.gov (United States)

Constantinides, Panos; Silverman, Stephen

2018-01-01

Purpose: This study examined the attitudes of Cypriot elementary school students toward physical education. Fourth, fifth and sixth grade students (N = 763) from six urban Cypriot elementary schools completed an attitude instrument. Methods: Adapting the attitude instrument for Greek-speaking students an extensive two-step pilot study showed the…

Dynamic model of elementary particles and the nature of mass and “electric” charge

OpenAIRE

Kreidik, Leonid G.; Institute of Mathematics & Physics, UTA; Shpenkov, George P.; Institute of Mathematics & Physics, UTA

2009-01-01

The physical model of elementary particles, based on the wave features of their behavior, is described here. Elementary particles are regarded as elementary dynamical structures of the microworld, interrelated with all levels of the Universe, i.e., inseparable from the structure of the Universe as a whole. Between any elementary particles and the ambient field of matter-space-time, as well as between elementary particles themselves, there exists an interchange of matter-space-time occurring b...

Enhanced emission of high-energy photons perpendicular to the reaction plane in α+Th reactions

International Nuclear Information System (INIS)

Tegner, P.; Marianski, B.; Morsch, H.P.; Rogge, M.; Bargholtz, C.; Decowski, P.; Zemlo, L.

1991-01-01

High-energy photon and neutron emission has been measured in coincidence with fission fragments in α+ 232 Th reactions at 170 MeV. From measurements parallel and perpendicular to the fission plane, anisotropies relative to the reaction plane were determined. The in-plane/out-of-plane intensity ratio is 0.72(7) for photons with energies above 20 MeV and 11(3) for neutrons at 35 MeV. The result for high-energy photons can be explained by nucleon-nucleon bremsstrahlung if the initial flow of nucleons has a correlation to the reaction plane similar to the one observed for fast neutrons

"Elementary, My Dear Shakespeare." Producing a Shakespearean Festival in the Elementary Schools.

Science.gov (United States)

Engen, Barbara; Campbell, Joy

Intended to give teachers usable information and prepared materials that are ready-to-reproduce for students, this book compiles research, tips, and teaching ideas into a sourcebook on teaching and producing William Shakespeare's plays in the elementary classroom. It is designed to bring the student into an awareness of Shakespeare's art and…

Cheap but accurate calculation of chemical reaction rate constants from ab initio data, via system-specific, black-box force fields.

Science.gov (United States)

Steffen, Julien; Hartke, Bernd

2017-10-28

Building on the recently published quantum-mechanically derived force field (QMDFF) and its empirical valence bond extension, EVB-QMDFF, it is now possible to generate a reliable potential energy surface for any given elementary reaction step in an essentially black box manner. This requires a limited and pre-defined set of reference data near the reaction path and generates an accurate approximation of the reference potential energy surface, on and off the reaction path. This intermediate representation can be used to generate reaction rate data, with far better accuracy and reliability than with traditional approaches based on transition state theory (TST) or variational extensions thereof (VTST), even if those include sophisticated tunneling corrections. However, the additional expense at the reference level remains very modest. We demonstrate all this for three arbitrarily chosen example reactions.

Cultural Astronomy in Elementary and Secondary School

Science.gov (United States)

Jafelice, Luiz Carlos

2015-07-01

This work is addressed to educators and geography, science, biology and physics teachers who deal with elementary, middle and high school education. It discusses the importance of adopting the anthropological perspective regarding issues that are considered within the astronomy area. It also presents practical proposals for those who intend to introduce cultural astronomy in elementary, middle and high school education - from the beginning of the 1st grade in Elementary school to the end of the 3rd grade in Secondary school, in formal as well as in informal education. This work is proposed within the context of the holistic and transdisciplinary environmental education. Our approach values above all the experience and aims at a humanistic education that includes epistemological and cultural diversities. The suggested practical proposals can be also beneficially used to address works that include contents related to Brazilian indigenous and Afro-descent cultures in the school curriculum, as the new law requires. The guidelines presented here were tested in real school situations.

Elementary particle physics in early physics education

CERN Document Server

Wiener, Gerfried

2017-01-01

Current physics education research is faced with the important question of how best to introduce elementary particle physics in the classroom early on. Therefore, a learning unit on the subatomic structure of matter was developed, which aims to introduce 12-year-olds to elementary particles and fundamental interactions. This unit was iteratively evaluated and developed by means of a design-based research project with grade-6 students. In addition, dedicated professional development programmes were set up to instruct high school teachers about the learning unit and enable them to investigate its didactical feasibility. Overall, the doctoral research project led to successful results and showed the topic of elementary particle physics to be a viable candidate for introducing modern physics in the classroom. Furthermore, thanks to the design-based research methodology, the respective findings have implications for both physics education and physics education research, which will be presented during the PhD defen...

Upper Elementary Teachers' Self-Efficacy and Spelling Instruction: A Qualitative Study

Science.gov (United States)

Fernandes, Brian E.

2017-01-01

A great deal of research has been conducted regarding spelling instruction at the early childhood and lower elementary levels, but not at the upper elementary level. This qualitative study explored the perceptions and experiences of upper elementary teachers to gain a better understanding of how they instruct spelling and their related…

A Study of Health Education and Its Needs for Elementary School Students

Science.gov (United States)

Hussain, Irshad; Alamgir, Muhammad Ahmad; Shahzad, Muhammad

2015-01-01

Health Education, particularly in elementary schools, appears to be a neglected area in Pakistan. This study investigated the health education needs of elementary school students. The purpose of the present study is to assess health education needs of elementary school students. The study adopted mix approach of (qualitative and quantitative)…

Incorporating Remote Robotic Telescopes into an Elementary Classroom Setting

Science.gov (United States)

Sharp, Zoe; Hock, Emily

2016-03-01

As Next Generation Science Standards (NGSS) are implemented across the nation, engaging and content-specific lessons are becoming an important addition to elementary classrooms. This paper demonstrate how effective hands-on teaching tactics, authentic learning, scientifically significant data, and research in the elementary realm can aid students in selfdiscovery about astronomy and uncover what it is to be a researcher and scientist. It also outlines an effective, engaging, and integrated classroom unit that is usable in both the scientific community and elementary schools. The lesson unit consists of NGSS science and engineering practices and performance expectations as well as California Common Core Standards (CCSS).

Silicon-based sleeve devices for chemical reactions

Science.gov (United States)

Northrup, M. Allen; Mariella, Jr., Raymond P.; Carrano, Anthony V.; Balch, Joseph W.

1996-01-01

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 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.

Delta-electron spectroscopy: An aid for the determination of reaction times in heavy ion reactions

International Nuclear Information System (INIS)

Skapa, H.

1983-01-01

For the systems I->Au and I->Bi at an incident energy of 6.2 MeV/u (I->Au) and 6.6 MeV/u (I->Bi) the emission probability of delta electrons was determined. In an energy range from 150 KeV to 1000 KeV electrons were spectroscoped in coincidence to elastically, quasielastically, and deep inelastically scattered ions. In deep inelastic reaction between reaction products with high and without a mean mass drift was discriminated. The contribution of the conversion electrons, determined from gamma spectra, extends in the range of deep inelastic reactions of about 60%. While the ratio of conversion electrons for deep inelastic events with large to such without mass drift shows a flat, monotoneous growth for the ratio of the measured emission probabilities a oscillation-like structure with about 400 KeV width results. An interpretation of this structure as interference effect by nuclear time delay yields for the case of large mass drift a nuclear retention time of 7.5 x 10 -21 s. (orig./HSI) [de

Transport description of damped nuclear reactions

International Nuclear Information System (INIS)

Randrup, J.

1984-01-01

This lecture series is concerned with the transport description of damped nuclear reactions. Part 1 is an elementary introduction to the general transport theory of nuclear dynamics. It can be read without any special knowledge of the field, although basic quantum mechanics is required for the formal derivation of the general expressions for the transport coefficients. The results can also be used in a wider context than the present one. Part 2 gives the student an up-to-date orientation about recent progress in the understanding of the angular-momentum variables in damped reactions. The emphasis is here on the qualitative understanding of the physics rather than the, at times somewhat tedious, formal derivations. More detailed presentations are due to be published soon. By necessity entire topics have been omitted. For example, no discussion is given of the calculation of the form factors, and the several instructive applications of the theory to transport of mass and change are not covered at all. For these topics they refer to the literature. It is hoped that the present notes provide a sufficient basis to make the literature on the subject accessible to the student

Elementary particle physics at the University of Florida. Annual progress report

Energy Technology Data Exchange (ETDEWEB)

1991-12-01

This report discusses research in the following areas: theoretical elementary particle physics; experimental elementary particle physics; axion project; SSC detector development; and computer acquisition. (LSP).

FY 1986 Report on research and development of super heat pump energy accumulation system. Part 2. Development of elementary techniques; 1986 nendo super heat pump energy shuseki system no kenkyu kaihatsu seika hokokusho. 2. Yoso gijutsu no kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1987-04-01

Summarized in detail herein are R and D results of the chemical heat storage techniques and plant simulation, for R and D of the super heat pump energy accumulation system. For R and D of the chemical heat storage techniques, the R and D efforts are directed to the researches on the fundamental reactions and continuous exothermic reactions involved for the high temperature heat storage type (utilizing the metathesis reactions); researches on the physical properties, heat storage systems, solid-phase reactions, liquid-phase reactors, corrosion of the materials, and so on for the high temperature heat storage type (utilizing ammonia complex); collection of the data related to media and structural materials, tests of the elementary equipment for the absorption and hydration reactions, and so on for the high temperature heat storage type (chemical heat storage utilizing hydration); researches on the media properties and system performance, tests of equipment, and so on for the high temperature heat storage type (heat storage/heating utilizing solvation); researches on the heat storage media, heat storage techniques, corrosion of the materials, systems, and so on for the low temperature heat storage type (utilizing the hydration reactions by mixing solutes); and researches on the media, corrosion and elementary equipment, optimization of the system, and so on for the low temperature heat storage type (clathrate low temperature heat storage systems). (NEDO)

Investigation of preservice elementary teachers' thinking about science

Science.gov (United States)

Cobern, William W.; Loving, Cathleen C.

2002-12-01

It is not uncommon to find media reports on the failures of science education, nor uncommon to hear prestigious scientists publicly lament the rise of antiscience attitudes. Given the position elementary teachers have in influencing children, antiscience sentiment among them would be a significant concern. Hence, this article reports on an investigation in which preservice elementary teachers responded to the Thinking about Science survey instrument. This newly developed instrument addresses the broadrelationship of science to nine important areas of society and culture and is intended to reveal the extent of views being consistent with or disagreeing with a commonly held worldview of science portrayed in the media and in popular science and science education literature. Results indicate that elementary teachers discriminate with respect to different aspects of culture and science but they are not antiscience.

Determination of fission gas yields from isotope ratios

DEFF Research Database (Denmark)

Mogensen, Mogens Bjerg

1983-01-01

This paper describes a method of calculating the actual fission yield of Kr and Xe in nuclear fuel including the effect of neutron capture reactions and decay. The bases for this calculation are the cumulative yields (ref. 1) of Kr and Xe isotopes (or pairs of isotopes) which are unaffected...... by neutron capture reactions, and measured Kr and Xe isotope ratios. Also the burnup contribution from the different fissile heavy isotopes must be known in order to get accurate fission gas yields....

Elementary analysis

CERN Document Server

Snell, K S; Langford, W J; Maxwell, E A

1966-01-01

Elementary Analysis, Volume 2 introduces several of the ideas of modern mathematics in a casual manner and provides the practical experience in algebraic and analytic operations that lays a sound foundation of basic skills. This book focuses on the nature of number, algebraic and logical structure, groups, rings, fields, vector spaces, matrices, sequences, limits, functions and inverse functions, complex numbers, and probability. The logical structure of analysis given through the treatment of differentiation and integration, with applications to the trigonometric and logarithmic functions, is

Elementary particles and physics interaction unification

International Nuclear Information System (INIS)

Leite-Lopes, J.

1985-01-01

Quantum theory and relativity theory are fundamental of relativistic quantum mechanics, quantum field theory, which is the base of elementary particle physics, gauge field theory and basic force unification models. After a short introduction of relativistic equations of the main fields, the free scalar field, the free vector field, the free electromagnetic field and the free spinor field, and of elementary particles and basic interactions, gauge invariance and electromagnetic gauge field are detailed. Then the presentation of internal degrees of freedom, especially isospin, introduces gauge field theory of Yang-Mills. At last weak interactions and strong interactions are presented and lead to grand unification theory in conclusion [fr

Elementary Science Resource Guide.

Science.gov (United States)

Texas Education Agency, Austin. Div. of Curriculum Development.

This guide for elementary teachers provides information on getting ideas into action, designing and implementing the right situation, ways in which to evaluate science process activities with students, and seven sample units. The units cover using the senses, magnets, forces, weather forecasting, classification of living things, and the physical…

DEPARTMENTALIZATION IN ELEMENTARY SCHOOLS.

Science.gov (United States)

American Association of School Administrators, Washington, DC.

THE RESULTS OF A SURVEY CONCERNED WITH DEPARTMENTALIZATION IN ELEMENTARY SCHOOLS ARE REPORTED IN STATISTICAL TABLES WHICH ARE ACCOMPANIED BY DESCRIPTIVE COMMENTARY. FOR THE PURPOSE OF THE SURVEY, THE DEFINITION OF DEPARTMENTALIZATION IS RESTRICTED TO INCLUDE ONLY THOSE SITUATIONS IN WHICH STUDENTS RECEIVE INSTRUCTION IN THE VARIOUS ACADEMIC…

Elementary principles of linear accelerators

International Nuclear Information System (INIS)

Loew, G.A.; Talman, R.

1983-09-01

These lectures come in five sections. The first is this introduction. The second is a short chronology of what are viewed as important milestones in the field. The third covers proton linacs. It introduces elementary concepts such as transit time, shunt impedance, and Q. Critical issues such as phase stability and transverse forces are discussed. The fourth section contains an elementary discussion of waveguide accelerating structures. It can be regarded as an introduction to some of the more advanced treatments of the subject. The final section is devoted to electron accelerators. Taking SLAC as an example, various topics are discussed such as structure design, choice of parameters, frequency optimization, beam current, emittance, bunch length and beam loading. Recent developments and future challenges are mentioned briefly. 41 figures, 4 tables

Finding the Hook: Computer Science Education in Elementary Contexts

Science.gov (United States)

Ozturk, Zehra; Dooley, Caitlin McMunn; Welch, Meghan

2018-01-01

The purpose of this study was to investigate how elementary teachers with little knowledge of computer science (CS) and project-based learning (PBL) experienced integrating CS through PBL as a part of a standards-based elementary curriculum in Grades 3-5. The researchers used qualitative constant comparison methods on field notes and reflections…

Elementary function calculation programs for the central processor-6

International Nuclear Information System (INIS)

Dobrolyubov, L.V.; Ovcharenko, G.A.; Potapova, V.A.

1976-01-01

Subprograms of elementary functions calculations are given for the central processor (CP AS-6). A procedure is described to obtain calculated formulae which represent the elementary functions as a polynomial. Standard programs for random numbers are considered. All the programs described are based upon the algorithms of respective programs for BESM computer

A Research on the Impact of Internet Use in American Elementary School Libraries

OpenAIRE

Feng-Hsiung Hou

2003-01-01

The purpose of this research was to explore the impact of Internet use in American elementary school libraries operations and to find the best way for use Internet tools in elementary school libraries operations. This study may offer important information about the impact of Internet usage for elementary school library s operations. The research question was: Is the Internet usage having significant impact for organizational operations in the American elementary school libraries? This study e...

Elementary amplitudes from full QCD and the stochastic vacuum model

International Nuclear Information System (INIS)

Martini, A.F.; Menon, M.J.

2002-01-01

In a previous work, making use of the gluon gauge-invariant two-point correlation function determined from lattice QCD in the quenched approximation and the stochastic vacuum model, we determined the elementary (parton-parton) scattering amplitude in the momentum transfer space. In this communication we compute the elementary amplitude from new lattice QCD calculations that include the effects of dynamical fermions (full QCD). The main conclusion is that the inclusion of dynamical fermions leads to a normalized elementary amplitude that decreases more quickly with the momentum transfer than that in the quenched approximation. (author)

Total dose effects on elementary transistors of a comparator in bipolar technology

International Nuclear Information System (INIS)

Sarrabayrouse, G.; Guerre, F.X.

1995-01-01

In the present work we investigate elementary transistors behaviour of an Integrated Circuit using junction isolation bipolar technology. Polarization conditions and dose rate effects on the main elementary transistor types are analysed. Furthermore, the IC electronic function degradations are studied. Finally, a comparison between the function degradations and the elementary component ones is attempted. (author)

On Adiabatic Processes at the Elementary Particle Level

OpenAIRE

A, Michaud

2016-01-01

Analysis of adiabatic processes at the elementary particle level and of the manner in which they correlate with the principle of conservation of energy, the principle of least action and entropy. Analysis of the initial and irreversible adiabatic acceleration sequence of newly created elementary particles and its relation to these principles. Exploration of the consequences if this first initial acceleration sequence is not subject to the principle of conservation.

Gamow-Teller transitions and neutron-proton-pair transfer reactions

Science.gov (United States)

Van Isacker, P.; Macchiavelli, A. O.

2018-05-01

We propose a schematic model of nucleons moving in spin-orbit partner levels, j = l ± 1/2, to explain Gamow-Teller and two-nucleon transfer data in N = Z nuclei above 40Ca. Use of the LS coupling scheme provides a more transparent approach to interpret the structure and reaction data. We apply the model to the analysis of charge-exchange, 42Ca(3He,t)42Sc, and np-transfer, 40Ca(3He,p)42Sc, reactions data to define the elementary modes of excitation in terms of both isovector and isoscalar pairs, whose properties can be determined by adjusting the parameters of the model (spin-orbit splitting, isovector pairing strength and quadrupole matrix element) to the available data. The overall agreement with experiment suggests that the approach captures the main physics ingredients and provides the basis for a boson approximation that can be extended to heavier nuclei. Our analysis also reveals that the SU(4)-symmetry limit is not realized in 42Sc.

Measurements of neutron-induced capture and fission reactions on $^{235}$ U: cross sections and ${\\alpha}$ ratios, photon strength functions and prompt ${\\gamma}$-ray from fission

CERN Multimedia

We propose to measure the neutron-induced capture cross section of the fissile isotope $^{235}$U using a fission tagging set-up. This new set-up has been tested successfully in 2010 and combines the n_TOF 4${\\pi}$ Total Absorption Calorimeter (TAC) with MicroMegas (MGAS) fission detectors. It has been proven that such a combination of detectors allows distinguishing with very good reliability the electromagnetic cascades from the capture reactions from dominant ${\\gamma}$-ray background coming from the fission reactions. The accurate discrimination of the fission background is the main challenge in the neutron capture cross section measurements of fissile isotopes. The main results from the measurement will be the associated capture cross section and ${\\alpha}$ ratio in the resolved (0.3-2250 eV) and unresolved (2.25-30 keV) resonance regions. According to the international benchmarks and as it is mentioned in the NEA High Priority Request List (HPRL), the 235U(n,${\\gamma}$) cross section is of utmost impo...

LSM-YSZ Reactions in Different Atmospheres

DEFF Research Database (Denmark)

Chen, Ming; Liu, Yi-Lin; Hagen, Anke

2009-01-01

-powder reaction. LSM reacts differently with YSZ in different atmospheres. In air, m-ZrO2 (monoclinic) is formed; while in N2, SrZrO3 and/or La2Zr2O7 are formed depending on the initial LSM/YSZ ratio. The reactions are reversible with varying P(O2) i.e. treating the sample in air after the heat treatment in N2...

The elementary school musical as an authentic, integrated performing arts experience

OpenAIRE

Bespflug, Kevin Sean

2009-01-01

While musicals are often common arts activities in high schools in North America, little has been written about their place in elementary schools. This is surprising when many elementary schools, particularly independent schools, are starting to include them in their fine arts programming. This thesis looks carefully at the elementary school musical by first undertaking a review of literature connected to the staging of musicals. The research and writings of various theorists and educators ar...

Nuclear excitations and reaction mechanisms. Progress report

International Nuclear Information System (INIS)

Fallieros, S.; Levin, F.S.

1986-01-01

Theoretical research is being conducted on the following topics: photon scattering, gauge invariance and the extension of Siefert's Theorem; retardation effects in photonuclear absorption and the Cabibbo Radicati Sum Rule; isovector transition densities, currents and response functions; the electric polarizability, the magnetic susceptibility and the distribution of oscillator strengths in some elementary systems; relativistic models and processes; properties of skyrmions; multiquark compound bags and the charge form factor of the A = 3 nuclei; nuclear reaction theory; three-particle scattering theory; deuteron-nucleus model calculations; asymptotia in three-particle scattering systems; and time-dependent approach to few-nucleon collisions. Progress in each of these areas is reviewed briefly. A list of invited talks and of publications for the fiscal year 1986 is included. 27 refs

Perceptions of Elementary School Children's Parents Regarding Sexuality Education

Science.gov (United States)

Fisher, Christine M.; Telljohann, Susan K.; Price, James H.; Dake, Joseph A.; Glassman, Tavis

2015-01-01

This study examined the preferences of parents of elementary school-aged children regarding when sexuality topics should be discussed in school and at home. The survey was mailed to a national random sample of parents of elementary school age children. Overall, 92% of parents believed that sexuality education should be taught in schools.…

Exploiting Elementary Landscapes for TSP, Vehicle Routing and Scheduling

Science.gov (United States)

2015-09-03

similar mathematical foundation to enable gradient descent methods for discrete combinatorial optimization problems. We are also generalizing our prior...research has exploited statistical and mathematical properties of elementary landscapes to develop new gradient methods for combinatorial optimization... mathematically methods to more automatically identify elementary landscapes. If a combinatorial optimization problem is a superposition of elemen

43 CFR 17.220 - Preschool, elementary, and secondary education.

Science.gov (United States)

2010-10-01

... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Preschool, elementary, and secondary education. 17.220 Section 17.220 Public Lands: Interior Office of the Secretary of the Interior NONDISCRIMINATION IN FEDERALLY ASSISTED PROGRAMS OF THE DEPARTMENT OF THE INTERIOR Nondiscrimination on the Basis of Handicap § 17.220 Preschool, elementary,...

A random spatial network model based on elementary postulates

Science.gov (United States)

Karlinger, Michael R.; Troutman, Brent M.

1989-01-01

A model for generating random spatial networks that is based on elementary postulates comparable to those of the random topology model is proposed. In contrast to the random topology model, this model ascribes a unique spatial specification to generated drainage networks, a distinguishing property of some network growth models. The simplicity of the postulates creates an opportunity for potential analytic investigations of the probabilistic structure of the drainage networks, while the spatial specification enables analyses of spatially dependent network properties. In the random topology model all drainage networks, conditioned on magnitude (number of first-order streams), are equally likely, whereas in this model all spanning trees of a grid, conditioned on area and drainage density, are equally likely. As a result, link lengths in the generated networks are not independent, as usually assumed in the random topology model. For a preliminary model evaluation, scale-dependent network characteristics, such as geometric diameter and link length properties, and topologic characteristics, such as bifurcation ratio, are computed for sets of drainage networks generated on square and rectangular grids. Statistics of the bifurcation and length ratios fall within the range of values reported for natural drainage networks, but geometric diameters tend to be relatively longer than those for natural networks.

Elementary steps and reaction pathways in the aqueous phase alkylation of phenol with ethanol

Energy Technology Data Exchange (ETDEWEB)

Eckstein, Sebastian; Hintermeier, Peter H.; Olarte, Mariefel V.; Liu, Yue; Baráth, Eszter; Lercher, Johannes A.

2017-08-01

The hydronium ion normalized reaction rate in aqueous phase alkylation of phenol with ethanol on H-MFI zeolites increases with decreasing concentration of acid sites. Higher rates are caused by higher concentrations of phenol in the zeolite pores, as the concentration of hydronium ions generated by zeolite Brønsted acid sites decreases. Considering the different concentrations of reacting species it is shown that the intrinsic rate constant for alkylation is independent of the concentration of hydronium ions in the zeolite pores. Alkylation at the aromatic ring of phenol and of toluene as well as O-alkylation of phenol have the same activation energy, 104 ± 5 kJ/mol. This is energetic barrier to form the ethyl carbenium ion from ethanol associated to the hydronium ion. Thus, in both the reaction pathways the catalyst involves a carbenium ion, which forms a bond to a nucleophilic oxygen (ether formation) or carbon (alkylation).

Elementary vectors

CERN Document Server

Wolstenholme, E Œ

1978-01-01

Elementary Vectors, Third Edition serves as an introductory course in vector analysis and is intended to present the theoretical and application aspects of vectors. The book covers topics that rigorously explain and provide definitions, principles, equations, and methods in vector analysis. Applications of vector methods to simple kinematical and dynamical problems; central forces and orbits; and solutions to geometrical problems are discussed as well. This edition of the text also provides an appendix, intended for students, which the author hopes to bridge the gap between theory and appl

Elementary metallography

Science.gov (United States)

Kazem, Sayyed M.

1992-01-01

Materials and Processes 1 (MET 141) is offered to freshmen by the Mechanical Engineering Department at Purdue University. The goal of MET 141 is to broaden the technical background of students who have not had any college science courses. Hence, applied physics, chemistry, and mathematics are included and quantitative problem solving is involved. In the elementary metallography experiment of this course, the objectives are: (1) introduce the vocabulary and establish outlook; (2) make qualitative observations and quantitative measurements; (3) demonstrate the proper use of equipment; and (4) review basic mathematics and science.

Does elementary school alcohol, tobacco, and marijuana use increase middle school risk?

Science.gov (United States)

Wilson, Nance; Battistich, Victor; Syme, S Leonard; Boyce, W Thomas

2002-06-01

To assess whether alcohol, tobacco, and other drug (ATOD) use in elementary school may have serious implications for continued ATOD use in middle school and beyond. Longitudinal analyses were conducted on questionnaire data from 331 middle school students who had previously provided ATOD-use data during elementary school. Non-school personnel administered questionnaires in three participating school districts in three different states. The sample of students was ethnically and geographically diverse, including students from a range of low socioeconomic status backgrounds living in rural, urban or inner-city environments. Middle school alcohol use was almost three times as likely to occur if alcohol use had occurred in elementary school (OR = 2.94, p Elementary school use of tobacco and marijuana also greatly increased the likelihood of middle school use (OR = 5.35, p elementary school, during the middle childhood years.

A determination of elementary separation factors of isotopes 235U and 238U in the ionic exchange process and of eluents in the water-glycerine system

International Nuclear Information System (INIS)

Murgulescu, S.E.

1977-01-01

In the experiments focused on uranium isotope separation by ion and chemical exchange, the water-glycerine system was employed. The principle of the method consists in shifting a uranium band along an ion-exchange resin column by means of an eluent. The isotope effect of reactions determining the band heading into the column where complex bands between the metal ion and the ligand form and break up under the resin influence, is determined by the difference in affinity between the two isotopes as against the eluent. The isotope effect in question determines a unit deviation of the equilibrium constant for the classical isotope exchange reaction. Starting from the experimental results obtained, it was concluded that the ion and chemical exchange between the IV and VI valence forms of uranium can be applied to isotope separation in terms of the separation unit. As against the methods that have been applied at present (gaseous scattering, hydro-extracting and the nozzle method), for which every new stage corresponds to a separation elementary factor, several separation elementary factors can be cumulated into a single stage in a chemical and ion exchange unit, by the optimization of the shifting band and length. (author)

The Science Semester: Cross-Disciplinary Inquiry for Prospective Elementary Teachers

Science.gov (United States)

Ford, Danielle J.; Fifield, Steve; Madsen, John; Qian, Xiaoyu

2013-10-01

We describe the Science Semester, a semester-long course block that integrates three science courses and a science education methods course for elementary teacher education majors, and examine prospective elementary teachers’ developing conceptions about inquiry, science teaching efficacy, and reflections on learning through inquiry. The Science Semester was designed to provide inquiry-oriented and problem-based learning experiences, opportunities to examine socially relevant issues through cross-disciplinary perspectives, and align with content found in elementary curricula and standards. By the end of the semester, prospective elementary teachers moved from naïve to intermediate understandings of inquiry and significantly increased self-efficacy for science teaching as measured on one subscore of the STEBI-B. Reflecting on the semester, prospective teachers understood and appreciated the goals of the course and the PBL format, but struggled with the open-ended and student-directed elements of the course.

Promoting Prospective Elementary Teachers' Learning to Use Formative Assessment for Life Science Instruction

Science.gov (United States)

Sabel, Jaime L.; Forbes, Cory T.; Zangori, Laura

2015-01-01

To support elementary students' learning of core, standards-based life science concepts highlighted in the "Next Generation Science Standards," prospective elementary teachers should develop an understanding of life science concepts and learn to apply their content knowledge in instructional practice to craft elementary science learning…

Another short and elementary proof of strong subadditivity of quantum entropy

Science.gov (United States)

Ruskai, Mary Beth

2007-08-01

A short and elementary proof of the joint convexity of relative entropy is presented, using nothing beyond linear algebra. The key ingredients are an easily verified integral representation and the strategy used to prove the Cauchy-Schwarz inequality in elementary courses. Several consequences are proved in a way which allows an elementary proof of strong subadditivity in a few more lines. Some expository material on Schwarz inequalities for operators and the Holevo bound for partial measurements is also included.

Preservice elementary teachers learning of astronomy

Science.gov (United States)

Fidler, Chuck Gary

The dissertation presents a new approach for the study of preservice elementary teacher astronomy education. The approach suggests that learning astronomical concepts are facilitated by greater sophistication in scale perception and spatial-aptitude. This dissertation is underscored by the national call for elementary science education reform efforts and suggests certain strategies shown more effective for the development of accurate astronomical comprehension. The present research study describes how preservice elementary teachers conceptualize and communicate ideas about Space. Instead of assuming a universal mental conception of cosmic orientations and relationships, the dissertation claims that the perception of Space related dimensions vary among preservice elementary teachers. Furthermore, the dissertation suggests individual perceptions of the scale sizes and orientations of celestial systems have direct influences on mental models used to organize and communicate astronomical information. The development of inaccurate mental models of the scaled dimensions of Space may perpetuate the teacher-student cycle of misconception and naive-theory generation among children in elementary education settings. The ability to conceptualize the vast cosmos is facilitated by the minds ability to think about vast scales and orientations of celestial objects. The Earth-based perspective of astronomy education compels the learner to think about astronomical principles within imaginary frames of reference and across unfamiliar scaled dimensions. Therefore, mental astronomical model building is underscored by the perception of scale and cosmic spatiality. This study suggests these cognitive skill sets are interconnected and facilitate the learning of accurate astronomy principles; as well as play an important role when designing an astronomy education program for preservice elementary teachers. This research study is comprised of three separate standalone articles designed and

Elementary School Mathematics Priorities

Science.gov (United States)

Wilson, W. Stephen

2009-01-01

This article first describes some of the basic skills and knowledge that a solid elementary school mathematics foundation requires. It then elaborates on several points germane to these practices. These are then followed with a discussion and conclude with final comments and suggestions for future research. The article sets out the five…

Elementary Energy Transfer Pathways in Allochromatium vinosum Photosynthetic Membranes.

Science.gov (United States)

Lüer, Larry; Carey, Anne-Marie; Henry, Sarah; Maiuri, Margherita; Hacking, Kirsty; Polli, Dario; Cerullo, Giulio; Cogdell, Richard J

2015-11-03

Allochromatium vinosum (formerly Chromatium vinosum) purple bacteria are known to adapt their light-harvesting strategy during growth according to environmental factors such as temperature and average light intensity. Under low light illumination or low ambient temperature conditions, most of the LH2 complexes in the photosynthetic membranes form a B820 exciton with reduced spectral overlap with LH1. To elucidate the reason for this light and temperature adaptation of the LH2 electronic structure, we performed broadband femtosecond transient absorption spectroscopy as a function of excitation wavelength in A. vinosum membranes. A target analysis of the acquired data yielded individual rate constants for all relevant elementary energy transfer (ET) processes. We found that the ET dynamics in high-light-grown membranes was well described by a homogeneous model, with forward and backward rate constants independent of the pump wavelength. Thus, the overall B800→B850→B890→ Reaction Center ET cascade is well described by simple triexponential kinetics. In the low-light-grown membranes, we found that the elementary backward transfer rate constant from B890 to B820 was strongly reduced compared with the corresponding constant from B890 to B850 in high-light-grown samples. The ET dynamics of low-light-grown membranes was strongly dependent on the pump wavelength, clearly showing that the excitation memory is not lost throughout the exciton lifetime. The observed pump energy dependence of the forward and backward ET rate constants suggests exciton diffusion via B850→ B850 transfer steps, making the overall ET dynamics nonexponential. Our results show that disorder plays a crucial role in our understanding of low-light adaptation in A. vinosum. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Elementary Energy Transfer Pathways in Allochromatium vinosum Photosynthetic Membranes

Energy Technology Data Exchange (ETDEWEB)

Lüer, Larry; Carey, Anne-Marie; Henry, Sarah; Maiuri, Margherita; Hacking, Kirsty; Polli, Dario; Cerullo, Giulio; Cogdell, Richard J.

2015-11-01

Allochromatium vinosum (formerly Chromatium vinosum) purple bacteria are known to adapt their light-harvesting strategy during growth according to environmental factors such as temperature and average light intensity. Under low light illumination or low ambient temperature conditions, most of the LH2 complexes in the photosynthetic membranes form a B820 exciton with reduced spectral overlap with LH1. To elucidate the reason for this light and temperature adaptation of the LH2 electronic structure, we performed broadband femtosecond transient absorption spectroscopy as a function of excitation wavelength in A. vinosum membranes. A target analysis of the acquired data yielded individual rate constants for all relevant elementary energy transfer (ET) processes. We found that the ET dynamics in high-light-grown membranes was well described by a homogeneous model, with forward and backward rate constants independent of the pump wavelength. Thus, the overall B800→B850→B890→ Reaction Center ET cascade is well described by simple triexponential kinetics. In the low-light-grown membranes, we found that the elementary backward transfer rate constant from B890 to B820 was strongly reduced compared with the corresponding constant from B890 to B850 in high-light-grown samples. The ET dynamics of low-light-grown membranes was strongly dependent on the pump wavelength, clearly showing that the excitation memory is not lost throughout the exciton lifetime. The observed pump energy dependence of the forward and backward ET rate constants suggests exciton diffusion via B850→ B850 transfer steps, making the overall ET dynamics nonexponential. Our results show that disorder plays a crucial role in our understanding of low-light adaptation in A. vinosum.

Principals' Opinions of Organisational Justice in Elementary Schools in Turkey

Science.gov (United States)

Aydin, Inayet; Karaman-Kepenekci, Yasemin

2008-01-01

Purpose--This study aims to present the opinions of public elementary school principals in Turkey about the current organisational justice practices among teachers from the distributive, procedural, interactional, and rectificatory dimensions. Design/methodology/approach--The opinions of 11 public elementary school principals in Ankara about…

Vector valued logarithmic residues and the extraction of elementary factors

NARCIS (Netherlands)

H. Bart (Harm); T. Ehrhardt; B. Silbermann

2007-01-01

textabstractAn analysis is presented of the circumstances under which, by the extraction of elementary factors, an analytic Banach algebra valued function can be transformed into one taking invertible values only. Elementary factors are generalizations of the simple scalar expressions λ – α, the

Tachyons: may they have a role in elementary particle physics

International Nuclear Information System (INIS)

Recami, E.; Rodrigues, W. A.

1985-01-01

The possible role of space like objects in elementary particle physics (and in quantum mechanics) is reviewed and discussed, mainly by exploiting the explicit consequences of the peculiar relativistic mechanics of tachyons. Particular attention is paid : 1) to tachyons as the possible carriers of interactions (''internal lines''); e.g., to the links between ''virtual particles'' and superluminal objects; 2) to the possibility of ''vacuum decays'' at the classical level; 3) to a Lorentz-invariant bootstrap model; 4) to the apparent shape of the tachyonic elementary particles (''elementary tachyons'') and its possible connection with the de Broglie wave-particle dualism

Tachyons: may they have a role in elementary particle physics

International Nuclear Information System (INIS)

Recami, E.; Rodrigues Junior, W.A.

1985-01-01

The possible role of space-like objects in elementary particle physics (and in quantum mechanics) is reviewed and discussed, mainly by exploiting the explicit consequences of the peculiar relativistic mechanics of Tachyons. Particular attention is paid: (i) to tachyons as the possible carriers of interactions ('internal lines'); e.g., to the links between 'virtual particles' and superluminal objects; (ii) to the possibility of 'vacuum decays' at the classical level; (iii) to a Lorentz-invariant bootstrap model; (iv) to the apparent shape of the tachyonic elementary particles ('elementary tachyons') and its possible connection with the de Broglie wave-particle dualism. (Author) [pt

Critical regimes driven by recurrent mobility patterns of reaction-diffusion processes in networks

Science.gov (United States)

Gómez-Gardeñes, J.; Soriano-Paños, D.; Arenas, A.

2018-04-01

Reaction-diffusion processes1 have been widely used to study dynamical processes in epidemics2-4 and ecology5 in networked metapopulations. In the context of epidemics6, reaction processes are understood as contagions within each subpopulation (patch), while diffusion represents the mobility of individuals between patches. Recently, the characteristics of human mobility7, such as its recurrent nature, have been proven crucial to understand the phase transition to endemic epidemic states8,9. Here, by developing a framework able to cope with the elementary epidemic processes, the spatial distribution of populations and the commuting mobility patterns, we discover three different critical regimes of the epidemic incidence as a function of these parameters. Interestingly, we reveal a regime of the reaction-diffussion process in which, counter-intuitively, mobility is detrimental to the spread of disease. We analytically determine the precise conditions for the emergence of any of the three possible critical regimes in real and synthetic networks.

Southern Association of Colleges and Schools Accreditation:Impact on Elementary Student Performance

Directory of Open Access Journals (Sweden)

Darlene Y. Bruner

2004-07-01

Full Text Available Currently, 848 Georgia public elementary schools that house third- and fifth-grades in the same building use the Southern Association of Colleges and Schools (SACS accreditation as a school improvement model. The purpose of this investigation was to determine whether elementary schools that are SACS accredited increased their levels of academic achievement at a higher rate over a five-year period than elementary schools that were not SACS accredited as measured by the Iowa Test of Basic Skills (ITBS. Independent variables included accreditation status, socioeconomic status (SES of schools, and baseline scores of academic achievement. Dependent variables included mathematics and reading achievement scores. There was a statistically significant difference found when examining the SES of schools and baseline scores of the elementary schools. SACS accredited elementary schools had higher SES and higher baseline scores in third- and fifth grade mathematics and reading. However, the multiple regression model indicated no statistically significant differences in gain scores between SACS accredited and non-SACS accredited elementary schools in third- and fifth-grade mathematics and reading achievement during the five year period examined in this study.

Locus of Control as It Relates to the Teaching Style of Elementary Teachers

Science.gov (United States)

Ture, Abidemi

2013-01-01

This research explored the relationship between elementary teachers' locus of control and teaching style. This research observed elementary teachers in their classrooms coupled with data gathered from information sheets, surveys, and interviews to determine if a relationship exists between the locus of control of the elementary teachers and…

Perceptions of Elementary School Students: Experiences and Dreams about the Life Studies Course

Science.gov (United States)

Baysal, Z. Nurdan; Tezcan, Özlem Apak; Araç, Kamil Ersin

2018-01-01

This study seeks to identify elementary school students' views and perceptions of the Life Studies course through verbal and visual instruments. It employs a descriptive phenomenological research design. The study surveyed second- and third-grade students attending one private elementary school and two state elementary schools. The data was…

Mathematical Models of Elementary Mathematics Learning and Performance. Final Report.

Science.gov (United States)

Suppes, Patrick

This project was concerned with the development of mathematical models of elementary mathematics learning and performance. Probabilistic finite automata and register machines with a finite number of registers were developed as models and extensively tested with data arising from the elementary-mathematics strand curriculum developed by the…

Investigation of organometallic reaction mechanisms with one and two dimensional vibrational spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Cahoon, James Francis [Univ. of California, Berkeley, CA (United States)

2008-12-01

One and two dimensional time-resolved vibrational spectroscopy has been used to investigate the elementary reactions of several prototypical organometallic complexes in room temperature solution. The electron transfer and ligand substitution reactions of photogenerated 17-electron organometallic radicals CpW(CO)₃ and CpFe(CO)₂ have been examined with one dimensional spectroscopy on the picosecond through microsecond time-scales, revealing the importance of caging effects and odd-electron intermediates in these reactions. Similarly, an investigation of the photophysics of the simple Fischer carbene complex Cr(CO)₅[CMe(OMe)] showed that this class of molecule undergoes an unusual molecular rearrangement on the picosecond time-scale, briefly forming a metal-ketene complex. Although time-resolved spectroscopy has long been used for these types of photoinitiated reactions, the advent of two dimensional vibrational spectroscopy (2D-IR) opens the possibility to examine the ultrafast dynamics of molecules under thermal equilibrium conditions. Using this method, the picosecond fluxional rearrangements of the model metal carbonyl Fe(CO)₅ have been examined, revealing the mechanism, time-scale, and transition state of the fluxional reaction. The success of this experiment demonstrates that 2D-IR is a powerful technique to examine the thermally-driven, ultrafast rearrangements of organometallic molecules in solution.

Teaching - learning plan on nuclear energy for elementary school

International Nuclear Information System (INIS)

2009-03-01

This is for teaching - learning curriculum about nuclear energy for elementary school students. It consist of four titles, which are I saved this much, learning energy through quiz, I work for nuclear power plant and would mayor build a nuclear power plant in our town? It was written to teach nuclear power plant and nuclear energy to elementary school students in easy way.

Elementary School Students Perception Levels of Problem Solving Skills

Science.gov (United States)

Yavuz, Günes; Yasemin, Deringöl; Arslan, Çigdem

2017-01-01

The purpose of this study is to reveal the perception levels of problem solving skills of elementary school students. The sample of the study is formed by totally 264 elementary students attending to 5th, 6th, 7th and 8th grade in a big city in Turkey. Data were collected by means of "Perception Scale for Problem Solving Skills" which…

Elementary teachers past experiences: A narrative study of the past personal and professional experiences of elementary teachers who use science to teach math and reading

Science.gov (United States)

Acre, Andrea M.

This qualitative study investigated the experiences of four elementary teachers who have elected to use science to teach math and reading/language arts in an attempt to identify what motivates them to do so. Identifying what experiences have motivated these teachers to go against the gain and teach elementary science in this current era of high-stakes tests is of the upmost importance given that science is being eliminated from the elementary curriculum and it is during the elementary years that students' nurture and develop their interest in science. Additionally, the United States is failing to produce enough college graduates in STEM areas to fill the thousands of STEM jobs each year. Through a review of the literature, the past trends and current trends of elementary science education were explored as well as teacher training. Furthermore, the literature reviewed inquiry teaching which is considered to be the most effective teaching method when teaching science at any level. Using John Dewey's Interest and Effort Relationship Theory and the Self-Determination Motivation Theory to guide this study, there were five prominent themes which emerged from the reconstructed stories of the four teachers: positive experiences with science, neutral/negative experiences with science, seeks meaningful professional development, influence and support from others, and regret/wants to do more.

Elementary children’s retrodictive reasoning about earth science

OpenAIRE

Matthew H. Schneps; Julie C. Libarkin

2012-01-01

We report on interviews conducted with twenty-one elementary school children (grades 1-5) about a number of Earth science concepts. These interviews were undertaken as part of a teacher training video series designed specifically to assist elementary teachers in learning essential ideas in Earth science. As such, children were interviewed about a wide array of earth science concepts, from rock formation to the Earth’s interior. We analyzed interview data primarily to determine whether or not ...

Relating Building and Classroom Conditions to Student Achievement in Virginia's Elementary Schools

OpenAIRE

Lanham III, James Warren

1999-01-01

The relationships between student achievement and a number of variables relating to building and classroom conditions in Virginia elementary schools were examined. A systematic random sample of 300 schools was selected from all elementary schools in Virginia with grades three and five. Data on building condition, classroom condition, and demographics were collected with "An Assessment of Building and Classroom Conditions in Elementary Schools in Virginia." Building prin...

USEEIO Elementary Flows and Life Cycle Impact Assessment (LCIA) Characterization Factors

Data.gov (United States)

U.S. Environmental Protection Agency — This file contains all the elementary flows (defined in ISO 14044) used in the USEEIO model. The elementary flows come from a draft master list used by USEPA...

Interaction of relativistic elementary atoms with matter. I. General formulas

International Nuclear Information System (INIS)

Mrowczyn'ski, S.

1987-01-01

The problem of the interaction of relativistic elementary atoms (Coulomb bound states of elementary particles such as positronium, pionium, etc.) with matter is studied in the reference frame where the atom is initially at rest. An atom of matter is treated as a spinless structureless fast particle. The amplitudes of elementary-atom interaction are derived in the Born approximation under the assumption that a momentum transfer to the atom does not significantly exceed an inverse Bohr radius of the atom. The elementary-atom excitation and ionization processes are considered. The transitions where the spin projection of the atom component is reversed are also studied. In particular the matrix elements for para-ortho and ortho-para transitions are given. The spin structure of the amplitudes is discussed in detail. The sum rules, which allow the calculation of the cross sections summed over atom final states are found. Finally the formulas of the atom interaction cross sections are presented

Eating Behavior and Childhood Overweight Among Population-Based Elementary Schoolchildren in Japan

Directory of Open Access Journals (Sweden)

Akatsuki Kokaze

2012-04-01

Full Text Available This study investigated the relationship between eating behavior and childhood overweight among population-based elementary schoolchildren in Japan. Data was collected from fourth graders (9 or 10 years of age from Ina Town, Saitama Prefecture, Japan from 1999 to 2009. Information about subjects’ sex, age, and lifestyle, including eating behaviors (eating until full and chewing thoroughly, was obtained using a self-administered questionnaire, and height and weight were measured directly. Overweight was determined according to the definition established by the International Obesity Task Force. Data from 4027 subjects (2079 boys and 1948 girls were analyzed. Chewing thoroughly was associated with a significantly decreased odds ratio (OR for being overweight, whereas eating until full significantly increased the OR for being overweight (OR: 1.50, 95% confidence interval: 1.16–1.94 among boys. However, eating until full was not associated with a significantly increased OR for being overweight among the group that reported chewing thoroughly, whereas it was associated with a significantly increased OR for being overweight (2.02, 1.38–2.94 among boys who did not chew thoroughly. In conclusion, eating until full or not chewing thoroughly was associated with being overweight among elementary schoolchildren. Results of this study suggest that chewing thoroughly may be an avenue to explore childhood overweight prevention efforts.

Preparing perservice teachers to teach elementary school science

Science.gov (United States)

Lewis, Amy D.

The development of scientifically literate citizens begins in the elementary school. Yet elementary school teachers are ill prepared to teach science (Trygstad, Smith, Banilower, Nelson, & Horizon Research, Inc., 2013). The research base on teacher preparation finds that programs designed to prepare elementary teachers are inadequate in providing both the content knowledge and pedagogical content knowledge necessary to teach science effectively (Baumgartner, 2010; Bodzin & Beerer, 2003; Bulunuz & Jarrett 2009). This mixed methods study examined what happened when a science methods course was interactively co-taught by an expert in elementary teaching methods and a physics expert. This study also aimed to discover what aspects of the curriculum pre-service teachers (PSTs) said helped them in developing their understanding of science content and scientific reasoning, and how to implement inquiry practices to teach science. A nested case study of three PSTs provided descriptive portraits of student experiences in the class. A whole class case analysis was used to examine what PSTs learned in terms of science, scientific reasoning skills, and pedagogical content knowledge (PCK) from their experiences in the course. It was found that students often conflated science content with the experiences they had in learning the content. Although PSTs felt the interactive co-teaching model effectively created a balance between theory and practice, it was their experiences doing science--conducting physical experiments, developing and discussing scientific models, and the use of inquiry-based instruction--that they credited for their learning. Even with careful curriculum planning, and a course purposely designed to bridge the theory to practice gap, this study found one semester-long methods course to be insufficient in providing the vast content knowledge and PCK elementary school science teachers need.

Quantitative elementary mode analysis of metabolic pathways: the example of yeast glycolysis

Directory of Open Access Journals (Sweden)

Kanehisa Minoru

2006-04-01

Full Text Available Abstract Background Elementary mode analysis of metabolic pathways has proven to be a valuable tool for assessing the properties and functions of biochemical systems. However, little comprehension of how individual elementary modes are used in real cellular states has been achieved so far. A quantitative measure of fluxes carried by individual elementary modes is of great help to identify dominant metabolic processes, and to understand how these processes are redistributed in biological cells in response to changes in environmental conditions, enzyme kinetics, or chemical concentrations. Results Selecting a valid decomposition of a flux distribution onto a set of elementary modes is not straightforward, since there is usually an infinite number of possible such decompositions. We first show that two recently introduced decompositions are very closely related and assign the same fluxes to reversible elementary modes. Then, we show how such decompositions can be used in combination with kinetic modelling to assess the effects of changes in enzyme kinetics on the usage of individual metabolic routes, and to analyse the range of attainable states in a metabolic system. This approach is illustrated by the example of yeast glycolysis. Our results indicate that only a small subset of the space of stoichiometrically feasible steady states is actually reached by the glycolysis system, even when large variation intervals are allowed for all kinetic parameters of the model. Among eight possible elementary modes, the standard glycolytic route remains dominant in all cases, and only one other elementary mode is able to gain significant flux values in steady state. Conclusion These results indicate that a combination of structural and kinetic modelling significantly constrains the range of possible behaviours of a metabolic system. All elementary modes are not equal contributors to physiological cellular states, and this approach may open a direction toward a

1,3,5-Triethylbenzene Transformation Reactions Compared to Its Transalkylation Reaction with Ethylbenzene

KAUST Repository

Akhtar, M. Naseem; Sulaiman, Al Khattaf

2009-01-01

The transalkylation of 1,3,5-triethylbenzene (1,3,5-TEB) with ethylbenzene (EB) has been studied over USYtype catalysts using a riser simulator that mimics the operation of a fluidized-bed reactor. The reaction mixture EB and 1,3,5-TEB was used at a molar ratio of 1:1, which is equivalent to 40:60 wt % of EB/1,3,5-TEB, respectively. The reaction temperature was varied from 350 to 500 °C with a time on stream ranging from 3-15 s. The effect of reaction conditions on 1,3,5-TEB conversion, DEB selectivity, and isomerization of 1,3,5-TEB is reported. The transalkylation of 1,3,5-TEB with EB has been compared to the transformation reaction of pure 1,3,5-TEB and EB. The experimental results have revealed that reactivity of 1,3,5-TEB and selectivity of DEB is increased during the transalkylation reaction (EB + 1,3,5-TEB) as compared to the transformation reaction of pure EB or 1,3,5-TEB. The 1,3,5-TEB undergoes isomerization and a cracking reaction to produce DEB and EB but does not undergo any appreciable disproportionation reaction. The isomerization of 1,3,5-TEB is more active at low temperatures, while cracking is more active at high temperatures. © 2009 American Chemical Society.

1,3,5-Triethylbenzene Transformation Reactions Compared to Its Transalkylation Reaction with Ethylbenzene

KAUST Repository

Akhtar, M. Naseem

2009-08-20

The transalkylation of 1,3,5-triethylbenzene (1,3,5-TEB) with ethylbenzene (EB) has been studied over USYtype catalysts using a riser simulator that mimics the operation of a fluidized-bed reactor. The reaction mixture EB and 1,3,5-TEB was used at a molar ratio of 1:1, which is equivalent to 40:60 wt % of EB/1,3,5-TEB, respectively. The reaction temperature was varied from 350 to 500 °C with a time on stream ranging from 3-15 s. The effect of reaction conditions on 1,3,5-TEB conversion, DEB selectivity, and isomerization of 1,3,5-TEB is reported. The transalkylation of 1,3,5-TEB with EB has been compared to the transformation reaction of pure 1,3,5-TEB and EB. The experimental results have revealed that reactivity of 1,3,5-TEB and selectivity of DEB is increased during the transalkylation reaction (EB + 1,3,5-TEB) as compared to the transformation reaction of pure EB or 1,3,5-TEB. The 1,3,5-TEB undergoes isomerization and a cracking reaction to produce DEB and EB but does not undergo any appreciable disproportionation reaction. The isomerization of 1,3,5-TEB is more active at low temperatures, while cracking is more active at high temperatures. © 2009 American Chemical Society.

Optimization of Maillard Reaction between Glucosamine and Other Precursors by Measuring Browning with a Spectrophotometer.

Science.gov (United States)

Ogutu, Benrick; Kim, Ye-Joo; Kim, Dae-Wook; Oh, Sang-Chul; Hong, Dong-Lee; Lee, Yang-Bong

2017-09-01

The individual Maillard reactions of glucose, glucosamine, cyclohexylamine, and benzylamine were studied at a fixed temperature of 120°C under different durations by monitoring the absorbance of the final products at 425 nm. Glucosamine was the most individually reactive compound, whereas the reactions of glucose, cyclohexylamine, and benzylamine were not significantly different from each other. Maillard reactions of reaction mixtures consisting of glucosamine-cyclohexylamine, glucosamine-benzylamine, glucose-cyclohexylamine, and glucose-benzylamine were also studied using different concentration ratios under different durations at a fixed temperature of 120°C and pH 9. Maillard reactions in the pairs involving glucosamine were observed to be more intense than those of the pairs involving glucose. Finally, with respect to the concentration ratios, it was observed that in most instances, optimal activity was realized, when the reaction mixtures were in the ratio of 1:1.

Global asymptotic stability of bistable traveling fronts in reaction-diffusion systems and their applications to biological models

International Nuclear Information System (INIS)

Wu Shiliang; Li Wantong

2009-01-01

This paper deals with the global asymptotic stability and uniqueness (up to translation) of bistable traveling fronts in a class of reaction-diffusion systems. The known results do not apply in solving these problems because the reaction terms do not satisfy the required monotone condition. To overcome the difficulty, a weak monotone condition is proposed for the reaction terms, which is called interval monotone condition. Under such a weak monotone condition, the existence and comparison theorem of solutions is first established for reaction-diffusion systems on R by appealing to the theory of abstract differential equations. The global asymptotic stability and uniqueness (up to translation) of bistable traveling fronts are then proved by the elementary super- and sub-solution comparison and squeezing methods for nonlinear evolution equations. Finally, these abstract results are applied to a two species competition-diffusion model and a system modeling man-environment-man epidemics.

Assessing Elementary Lesions in Gout by Ultrasound

DEFF Research Database (Denmark)

Terslev, Lene; Gutierrez, Marwin; Christensen, Robin

2015-01-01

OBJECTIVE: To test the reliability of the consensus-based ultrasound (US) definitions of elementary gout lesions in patients. METHODS: Eight patients with microscopically proven gout were evaluated by 16 sonographers for signs of double contour (DC), aggregates, erosions, and tophi in the first......, respectively. The best reliability was seen for erosions (κ 0.74, 95% CI 0.65-0.81) and lowest for aggregates (κ 0.21, 95% CI 0.04-0.37). CONCLUSION: This is the first step to test consensus-based US definitions on elementary lesions in patients with gout. High intraobserver reliability was found when applying...

Inappropriate Lessons: Elementary Schools and the Social Organization of Sexuality

Science.gov (United States)

Boas, Erica Misako

2013-01-01

This dissertation responds to the question: How is sexuality organized in elementary schools? I argue that despite the absence of overt discussions on sexuality in elementary schools, sexuality is "organized" through social processes that are recursively linked to ideology. Due to the widely held belief that "children" and…

Common Core Implementation Decisions Made by Principals in Elementary Schools

Science.gov (United States)

Norman, Alexis Cienfuegos

2016-01-01

The purpose of this study was to understand the decisions elementary principals have made during the Common Core State Standards reform. Specifically, (a) what decisions principals have made to support Common Core implementation, (b) what strategies elementary principals have employed to communicate with stakeholders about Common Core State…

Reconceptualizing Elementary Teacher Preparation : A case for informal science education

NARCIS (Netherlands)

Avraamidou, Lucy

2015-01-01

The purpose of this case study was to explore the ways in which 3 different informal science experiences in the context of an elementary methods course influenced a group of prospective elementary teachers' ideas about science teaching and learning as well as their understandings about the role of

Upper Elementary Students' Motivation to Read Fiction and Nonfiction

Science.gov (United States)

Parsons, Allison Ward; Parsons, Seth A.; Malloy, Jacquelynn A.; Gambrell, Linda B.; Marinak, Barbara A.; Reutzel, D. Ray; Applegate, Mary D.; Applegate, Anthony J.; Fawson, Parker C.

2018-01-01

This research explores upper elementary students' motivation to read fiction and nonfiction. Using expectancy-value theory, the researchers developed separate surveys to measure motivation to read fiction and nonfiction. Researchers administered surveys to 1,104 upper elementary students (grades 3-6) in multiple locations across the United States…

Roles of Teachers in Orchestrating Learning in Elementary Science Classrooms

Science.gov (United States)

Zhai, Junqing; Tan, Aik-Ling

2015-01-01

This study delves into the different roles that elementary science teachers play in the classroom to orchestrate science learning opportunities for students. Examining the classroom practices of three elementary science teachers in Singapore, we found that teachers shuttle between four key roles in enabling student learning in science. Teachers…

Reaction of ketene ions with ammonia

International Nuclear Information System (INIS)

Iraqi, M.; Lifshitz, C.; Reuben, B.G.

1991-01-01

Reactions of ketene ions with NH 3 , ND 3 , H 2 O, and CH 4 were investigated in a selected ion flow tube (SIFT). There were no observable products for H 2 O and CH 4 and no ion/neutral complex stabilization in any of the systems investigated. The ammonia system demonstrated two reaction channels, in agreement with previous FTICR data (1) distonic ion CH 2 NH 3 sm-bullet + formation, with a branching ratio of 0.2 and (2) proton transfer, with a branching ratio of 0.8. The overall second-order rate constant for NH 3 is (2.2 ± 0.15) x 10 -9 cm 3 molecule -1 s -1 , in agreement with the gas kinetic ion-dipole collision rate. Isotope scrambling was studied for primary (CH 2 CO + ) and for secondary (CH 2 NX 3 sm-bullet + and NX 4 + , X = H or D) proton-transfer reactions with ND 3 ; CH 2 NH 3 sm-bullet + appears to transfer an X + ion to ND 3 without any scrambling. CH 2 CO sm-bullet + undergoes reactions with partial scrambling and NX 4 + seems to react with almost complete scrambling. The results are compared with these of Adams, Smith, and Henchman on the NH 4 + /ND 3 system

Influence of passive smoking on learning in elementary school.

Science.gov (United States)

Jorge, Juliana Gomes; Botelho, Clóvis; Silva, Ageo Mário Cândido; Moi, Gisele Pedroso

2016-01-01

To analyze the association between household smoking and the development of learning in elementary schoolchildren. Cross-sectional study with 785 students from the 2nd to the 5th year of elementary school. Students were evaluated by the School Literacy Screening Protocol to identify the presence of learning disabilities. Mothers/guardians were interviewed at home through a validated questionnaire. Descriptive and bivariate analysis, as well as multivariate Poisson regression, were performed. In the final model, the variables associated with learning difficulties were current smoking at the household in the presence of the child (PR=6.10, 95% CI: 4.56 to 8.16), maternal passive smoking during pregnancy (PR=1.46, 95% CI: 1.07 to 2.01), students attending the 2nd and 3rd years of Elementary School (PR=1.44, 95% CI: 1.10 to 1.90), and being children of mothers with only elementary level education (PR=1.36, 95% CI: 1.04 to 1.79). The study demonstrated an association between passive exposure to tobacco smoke and learning difficulties at school. Copyright © 2016 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Playing Golf Is Elementary

Science.gov (United States)

Goldman, Jill S.; Pfluge, Kevin F.

2010-01-01

Golf is a lifelong activity that people of all ages can enjoy if they experience success and have fun. Early involvement in the sport facilitates the development of the ability to strike an object with an implement. Striking with implements can be challenging for young children and teachers, but golf can be taught in all elementary school settings…

Do You Really Want to Know? Elementary Music Personnel and Potential in Utah

Science.gov (United States)

Walker, Loretta Niebur

2015-01-01

This is the second of two articles reporting the results of a study by the author regarding the status of elementary music education in the state of Utah. This article focuses on the qualifications of Utah's elementary music teachers (music certified, elementary classroom certified, artists-in-residence, volunteers, and paraprofessionals) and the…

The Effects of Social Capital Levels in Elementary Schools on Organizational Information Sharing

Science.gov (United States)

Ekinci, Abdurrahman

2012-01-01

This study aims to assess the effects of social capital levels at elementary schools on organizational information sharing as reported by teachers. Participants were 267 teachers selected randomly from 16 elementary schools; schools also selected randomly among 42 elementary schools located in the city center of Batman. The data were analyzed by…

Inclusive reconstruction of hadron resonances in elementary and heavy-ion collisions with HADES

Directory of Open Access Journals (Sweden)

Kornakov Georgy

2016-01-01

Full Text Available The unambiguous identification of hadron modifications in hot and dense QCD matter is one of the important goals in nuclear physics. In the regime of 1 - 2 GeV kinetic energy per nucleon, HADES has measured rare and penetrating probes in elementary and heavy-ion collisions. The main creation mechanism of mesons is the excitation and decay of baryonic resonances throughout the fireball evolution. The reconstruction of shortlived (≈ 1 fm/c resonance states through their decay products is notoriously difficult. We have developed a new iterative algorithm, which builds the best hypothesis of signal and background by distortion of individual particle properties. This allows to extract signals with signal-to-background ratios of <1%.

Inclusive reconstruction of hadron resonances in elementary and heavy-ion collisions with HADES

Science.gov (United States)

Kornakov, Georgy

2016-11-01

The unambiguous identification of hadron modifications in hot and dense QCD matter is one of the important goals in nuclear physics. In the regime of 1 - 2 GeV kinetic energy per nucleon, HADES has measured rare and penetrating probes in elementary and heavy-ion collisions. The main creation mechanism of mesons is the excitation and decay of baryonic resonances throughout the fireball evolution. The reconstruction of shortlived (≈ 1 fm/c) resonance states through their decay products is notoriously difficult. We have developed a new iterative algorithm, which builds the best hypothesis of signal and background by distortion of individual particle properties. This allows to extract signals with signal-to-background ratios of <1%.

Practices of Elementary Principals in Influencing New Teachers to Remain in Education

OpenAIRE

Palermo, Thelma D.

2002-01-01

The grounded theory presented in this study describes practices elementary principals utilize in influencing new teachers to remain in education. Eleven teachers and three elementary principals from one school division in Virginia participated in this study. Interview data were collected, elementary principals were shadowed, and documents were analyzed. Thematic categories and sub categories were formed through data analysis. The grounded theory that resulted from this study is: principals wh...

Ratio of tritiated water and hydrogen generated in mercury through a nuclear reaction

Energy Technology Data Exchange (ETDEWEB)

Manabe, K. [Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency (JAEA), Tokai, Naka-gun, Ibaraki 319-1195 (Japan)], E-mail: manabe.kentaro@jaea.go.jp; Yokoyama, S. [Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency (JAEA), Tokai, Naka-gun, Ibaraki 319-1195 (Japan)

2008-02-15

Tritium generated in a mercury target is a source of potential exposure of personnel at high-energy accelerator facilities. Knowledge of the chemical form of tritium is necessary to estimate the internal doses. We studied the tritium generation upon thermal neutron irradiation of a mercury target modified into liquid lithium amalgam to examine the ratio of tritiated water ([{sup 3}H]H{sub 2}O) and tritiated hydrogen ([{sup 3}H]H{sub 2}). The ratio between [{sup 3}H]H{sub 2}O and [{sup 3}H]H{sub 2} generated in lithium amalgam was 4:6 under these experimental conditions.

American Elementary Education Pre-Service Teachers' Attitudes towards Biotechnology Processes

Science.gov (United States)

Chabalengula, Vivien Mweene; Mumba, Frackson; Chitiyo, Jonathan

2011-01-01

This study examined elementary education pre-service teachers' attitudes towards biotechnology processes. A sample comprised 88 elementary education pre-service teachers at a mid-sized university in the Midwest of the USA. Sixty and 28 of these pre-service teachers were enrolled in Introductory Science Methods course and Advance Science Methods…

Industrial Arts: Vehicle for Career Awareness in the Elementary School

Science.gov (United States)

Wircenski, Jerry L.; Fales, James F.

1977-01-01

The authors propose the use of industrial arts as a vehicle for providing career awareness in the elementary school. They cite a 2-week integrated unit in manufacturing conducted at Hershey Elementary School (Lafayette, Indiana) where the curriculum encouraged second and third graders to explore the world of work. (Editor/HD)

Elementary Pre-Service Teachers' Mathematics Anxiety and Mathematics Teaching Anxiety

Science.gov (United States)

Haciomeroglu, Guney

2014-01-01

The present study examined the structure of elementary pre-service teachers' mathematics anxiety and mathematics teaching anxiety by asking whether the two systems of anxiety are related. The Turkish Mathematics Anxiety Rating Scale Short Version and the Mathematics Teaching Anxiety Scale were administered to 260 elementary pre-service teachers.…

Balance Sheet for Catholic Elementary Schools: 2001 Income and Expenses.

Science.gov (United States)

Kealey, Robert J.

This financial report was designed to provide a basis for informed discussion regarding potential forms of federal and state assistance to students attending Catholic elementary schools, and to encourage improved local management. The information presented in this study is based upon a random sample of Catholic elementary schools across the United…

Influence of alcohol: oil molar ratio on the production of ethyl esters ...

African Journals Online (AJOL)

The influence of alcohol:oil molar ratio on the canola oil transesterification reaction in solvent-free medium using free lipase from Thermomyces lanuginosus and Burkholderia cepacia was studied. The experiments conducted in batch reactor for 72 h at 37°C in cosolvent-free reaction system with ethanol addition in three ...

Mathematics Anxiety and Beliefs of Turkish Pre-Service Elementary Teachers

Science.gov (United States)

Uysal, Figen; Dede, Yüksel

2016-01-01

The purpose of this study was to investigate the relationship between pre-service elementary teachers' mathematics teaching beliefs and mathematics anxiety. The participants of the study consist of 96 pre-service elementary teachers from a department of primary education in a state university in Turkey during the 2010-2011 spring term. Mathematics…

Collective Student Trust: A Social Resource for Urban Elementary Students

Science.gov (United States)

Adams, Curt M.

2014-01-01

Purpose: The purpose of this study was to determine if collective student trust functions as a resource for urban elementary students. Methods: Data from 1,646 students nested in 56 elementary schools in an urban school district were used to test the hypothesized effect of collective student trust on school identification, self-regulated…

Prospective elementary and secondary school mathematics teachers’ statistical reasoning

Directory of Open Access Journals (Sweden)

Rabia KARATOPRAK

2015-04-01

Full Text Available This study investigated prospective elementary (PEMTs and secondary (PSMTs school mathematics teachers’ statistical reasoning. The study began with the adaptation of the Statistical Reasoning Assessment (Garfield, 2003 test. Then, the test was administered to 82 PEMTs and 91 PSMTs in a metropolitan city of Turkey. Results showed that both groups were equally successful in understanding independence, and understanding importance of large samples. However, results from selecting appropriate measures of center together with the misconceptions assessing the same subscales showed that both groups selected mode rather than mean as an appropriate average. This suggested their lack of attention to the categorical and interval/ratio variables while examining data. Similarly, both groups were successful in interpreting and computing probability; however, they had equiprobability bias, law of small numbers and representativeness misconceptions. The results imply a change in some questions in the Statistical Reasoning Assessment test and that teacher training programs should include statistics courses focusing on studying characteristics of samples.

A Phenomenological Narrative Study: Elementary Charter School Principals' Managerial Roles

Science.gov (United States)

Cetinkaya, Ahmet

2016-01-01

This study was a phenomenological narrative research investigating the managerial roles of elementary charter school principals. Managerial leadership practices were investigated under three categories personnel management, student management, and finance management. Elementary charter school principals provided positive feedback for having small…

The Sun as a system of elementary particles

International Nuclear Information System (INIS)

Kleczek, J.

1986-01-01

The paper based on known facts of solar physics-is an attempt to interpret the Sun as a selfgravitating system of about 10/sup 57/ nucleons and electrons. These elementary particles are endowed with strong, electromagnetic, weak and gravitational interactions. Origin of the Sun, its evolution, structure and physiology are consequences of the four interactions. Each structural property, every evolutionary process, any activity phenomenon or event on the Sun can be traced backwards to the four fundamental forces of nature, viz. to interactions of elementary particles

Developing Elementary Science PCK for Teacher Education: Lessons Learned from a Second Grade Partnership

Science.gov (United States)

Bradbury, Leslie U.; Wilson, Rachel E.; Brookshire, Laura E.

2017-06-01

In this self-study, two science educators partnered with two elementary teachers to plan, implement, and reflect on a unit taught in second grade classrooms that integrated science and language arts. The researchers hoped to increase their pedagogical content knowledge (PCK) for elementary science teaching so that they might use their experiences working in an elementary context to modify their practices in their elementary science method instruction. The research question guiding the study was: What aspects of our PCK for elementary science teaching do we as science educators develop by co-planning, co-teaching, and reflecting with second grade teachers? Data include transcripts of planning meetings, oral reflections about the experience, and videos of the unit being enacted. Findings indicate that managing resources for science teaching, organizing students for science learning, and reflecting on science teaching were themes prevalent in the data. These themes were linked to the model of PCK developed by Park and Oliver (Research in Science Education, 38, 261-284, 2008) and demonstrate that we developed PCK for elementary science teaching in several areas. In our discussion, we include several proposed changes for our elementary science methods course based on the outcomes of the study.

Reconceptualizing Elementary Teacher Preparation: A Case for Informal Science Education

Science.gov (United States)

Avraamidou, Lucy

2015-01-01

The purpose of this case study was to explore the ways in which 3 different informal science experiences in the context of an elementary methods course influenced a group of prospective elementary teachers' ideas about science teaching and learning as well as their understandings about the role of informal science environments to teaching and…

41 CFR 101-6.205-3 - Elementary and secondary schools.

Science.gov (United States)

2010-07-01

... schools. 101-6.205-3 Section 101-6.205-3 Public Contracts and Property Management Federal Property...-Nondiscrimination in Programs Receiving Federal Financial Assistance § 101-6.205-3 Elementary and secondary schools. The requirements of §§ 101-6.205-1 and 101-6.205-2 with respect to any elementary or secondary school...

Acoustical conditions for speech communication in active elementary school classrooms

Science.gov (United States)

Sato, Hiroshi; Bradley, John

2005-04-01

Detailed acoustical measurements were made in 34 active elementary school classrooms with typical rectangular room shape in schools near Ottawa, Canada. There was an average of 21 students in classrooms. The measurements were made to obtain accurate indications of the acoustical quality of conditions for speech communication during actual teaching activities. Mean speech and noise levels were determined from the distribution of recorded sound levels and the average speech-to-noise ratio was 11 dBA. Measured mid-frequency reverberation times (RT) during the same occupied conditions varied from 0.3 to 0.6 s, and were a little less than for the unoccupied rooms. RT values were not related to noise levels. Octave band speech and noise levels, useful-to-detrimental ratios, and Speech Transmission Index values were also determined. Key results included: (1) The average vocal effort of teachers corresponded to louder than Pearsons Raised voice level; (2) teachers increase their voice level to overcome ambient noise; (3) effective speech levels can be enhanced by up to 5 dB by early reflection energy; and (4) student activity is seen to be the dominant noise source, increasing average noise levels by up to 10 dBA during teaching activities. [Work supported by CLLRnet.

Mathematics, Language, and Learning: A Longitudinal Study of Elementary Teachers and Their Mathematics Teaching Practices

OpenAIRE

Yeh, Cathery

2016-01-01

Elementary school mathematics has gained increased attention in the last few decades. A growing field of research has studied the programmatic design and development of elementary mathematics teaching in teacher education, however, few studies have examined longitudinally the mathematics teaching of novice elementary teachers. Existing longitudinal studies on elementary mathematics teaching have generally focused on the effects of teacher preparation on their beginning practices and have exam...

An Exploration of Elementary School Counselors' Perceptions of Students' Exposure to Violent Video Games

Science.gov (United States)

Woody, Tammy Lynn

2010-01-01

This study explored elementary school counselors' perceptions of working with students exposed to violent video games. Certified elementary school counselors participated in both an online survey and individual interviews, revealing their observations regarding elementary school children and the phenomenon of gaming. An emphasis was placed on…

Prioritizing Elementary School Writing Instruction: Cultivating Middle School Readiness for Students with Learning Disabilities

Science.gov (United States)

Ciullo, Stephen; Mason, Linda

2017-01-01

Helping elementary students with learning disabilities (LD) prepare for the rigor of middle school writing is an instructional priority. Fortunately, several standards-based skills in upper elementary school and middle school overlap. Teachers in upper elementary grades, specifically fourth and fifth grades, have the opportunity to provide…

Topics in elementary particle physics

International Nuclear Information System (INIS)

Dugan, M.J.

1985-01-01

Topics in elementary particle physics are discussed. Models with N = 2 supersymmetry are constructed. The CP violation properties of a class of N = 1 supergravity models are analyzed. The structure of a composite Higgs model is investigated. The implications of a 17 keV neutrino are considered

The evaluation of the polarization resistance in a tubular electrode and its application to the hydrogen electrode reaction

International Nuclear Information System (INIS)

Montero, M.A.; Marozzi, C.A.; Chialvo, M.R. Gennero de; Chialvo, A.C.

2007-01-01

An alternative method for the determination of the kinetic parameters involved in the elementary steps of the reaction mechanism of the hydrogen electrode reaction is proposed. It is based on the determination of the variation of the polarization resistance in a tubular platinum electrode with a laminar flow of electrolyte as a function of the activity of protons of the electrolyte solution. A theoretical expression that relates the experimental variables and the equilibrium polarization resistance is developed, which takes into account the current distribution along the electrode surface. The results are compared with others obtained previously, contributing to the verification of the kinetic mechanism through a completely different experimental procedure

REACTIONS FORMING Cn=2,10(0,+), Cn=2,4H(0,+), AND C3H2(0,+) IN THE GAS PHASE: SEMIEMPIRICAL BRANCHING RATIOS

International Nuclear Information System (INIS)

Chabot, M.; Jallat, A.; Béroff, K.; Gratier, P.; Wakelam, V.

2013-01-01

The aim of this paper is to provide a new set of branching ratios (BRs) for interstellar and planetary chemical networks based on a semiempirical model. We applied, instead of zero-order theory (i.e., only the most exoergic decaying channel is considered), a statistical microcanonical model based on the construction of breakdown curves and using experimental high velocity collision BRs for their parameterization. We applied the model to ion-molecule, neutral-neutral, and ion-pair reactions implemented in the few popular databases for astrochemistry, such as KIDA, OSU, and UMIST. We studied the reactions of carbon and hydrocarbon species with electrons, He + , H + , CH + , CH, C, and C + leading to intermediate complexes of the type C n=2,10 , C n=2,4 H, C 3 H 2 , C n=2,10 + , C n=2,4 H + , or C 3 H 2 + . Comparison of predictions with measurements supports the validity of the model. Huge deviations with respect to database values are often obtained. Effects of the new BRs in time-dependent chemistry for dark clouds and for photodissociation region chemistry with conditions similar to those found in the Horsehead Nebula are discussed.

String model of elementary particles

International Nuclear Information System (INIS)

Kikkawa, Keiji

1975-01-01

Recent development of the models of elementary particles is described. The principal features of elementary particle physics can be expressed by quark model, mass spectrum, the Regge behavior of scattering amplitude, and duality. Venezians showed in 1968 that the B function can express these features. From the analysis of mass spectrum, the string model was introduced. The quantization of the string is performed with the same procedure as the ordinary quantum mechanics. The motion of the string is determined by the Nambu-Goto action integral, and the Schroedinger equation is obtained. Mass spectrum from the string model was same as that from the duality model such as Veneziano model. The interaction between strings can be introduced, and the Lagrangian can be formulated. The relation between the string model and the duality model has been studied. The string model is the first theory of non-local field, and the further development is attractive. The relation between this model and the quark model is still not clear. (Kato, T.)

Elementary Particles A New Approach

Directory of Open Access Journals (Sweden)

FranciscoMartnezFlores.

2015-07-01

Full Text Available ABSTRACT It is shown the inexistence of neutrinos to define precisely the concept of relativistics mass under this scheme to elementarys particles as electron and interactions particles like photons correspond an electromagnetic and virtual mass. Nucleons protons and neutrons have real or inertial mass for being composite particles since inertia needs structure it is provided by an interactive network originated by strong and weak forces. This mass is building up atoms and all the material world under Classical Physics and Chemistrys laws.These actual masses may be considered as electromagnetic and virtual one thanks to its charge in order to establish the high energies level needed to obtain all particles physics elementary or not which are governed by the laws of Quantum Physics. With all this one may set up amore reasonable and understandable new Standard Model which being projected into Cosmological Model can get rid of some inconsistencies and concepts difficult to be admitted.

READING PERFORMANCE OF ELEMENTARY STUDENT TEACHERS IN A DEVELOPING INSTITUTION.

Science.gov (United States)

ADAMS, EFFIE KAYE

A STUDY WAS CONDUCTED AT BISHOP COLLEGE, DALLAS, TEXAS, TO EXAMINE THE READING NEEDS OF PROSPECTIVE ELEMENTARY TEACHERS. SCORES ON THE NELSON DENNY READING TESTS, ADVANCED FORM A, ON THE OTIS QUICK SCORING TESTS OF MENTAL ABILITY, GAMMA FORM BM, AND GRADE POINT AVERAGES COVERING 4 YEARS OF COLLEGE WORK WERE ANALYZED FOR 29 NEGRO ELEMENTARY STUDENT…

The synthesis of PdPt/carbon paper via surface limited redox replacement reactions for oxygen reduction reaction

CSIR Research Space (South Africa)

Motsoeneng, RG

2015-09-01

Full Text Available Surface-limited redox replacement reactions using the electrochemical atomic layer deposition (EC-ALD) technique were used to synthesize PdPt bimetallic electrocatalysts on carbon paper substrate. Electrocatalysts having different Pd:Pt ratio were...

The origin of mass elementary particles and fundamental symmetries

CERN Document Server

Iliopoulos, John

2017-01-01

The discovery of a new elementary particle at the Large Hadron Collider at CERN in 2012 made headlines in world media. Since we already know of a large number of elementary particles, why did this latest discovery generate so much excitement? This small book reveals that this particle provides the key to understanding one of the most extraordinary phenomena which occurred in the early Universe. It introduces the mechanism that made possible, within tiny fractions of a second after the Big Bang, the generation of massive particles. The Origin of Mass is a guided tour of cosmic evolution, from the Big Bang to the elementary particles we study in our accelerators today. The guiding principle of this book is a concept of symmetry which, in a profound and fascinating way, seems to determine the structure of the Universe.

Activation cross section and isomeric cross section ratios for the (n ,2 n ) reaction on 153Eu

Science.gov (United States)

Luo, Junhua; Jiang, Li; Li, Suyuan

2017-10-01

The 153Eu(n ,2 n ) m1,m2,g152Eu cross section was measured by means of the activation technique at three neutron energies in the range 13-15 MeV. The quasimonoenergetic neutron beam was formed via the 3H(d ,n ) 4He reaction, in the Pd-300 Neutron Generator at the Chinese Academy of Engineering Physics (CAEP). The activities induced in the reaction products were measured using high-resolution γ-ray spectroscopy. The cross section of the population of the second high-spin (8-) isomeric state was measured along with the reaction cross section populating both the ground (3-) and the first isomeric state (0-). Cross sections were also evaluated theoretically using the numerical code TALYS-1.8, with different level density options at neutron energies varying from the reaction threshold to 20 MeV. Results are discussed and compared with the corresponding literature.

Effect of Si/Al2 Ratio on 2-butanol Dehydration over HY Zeolite Catalysts

International Nuclear Information System (INIS)

Jung, Euna; Choi, Hyeonhee; Jeon, Jong-Ki

2015-01-01

Synthesis of butenes through dehydration of 2-butanol was investigated over HY zeolite catalysts. 2-Butanol dehydration reaction was carried out in a fixed bed catalytic reactor. 2-Butanol conversion was increased with increase of Si/Al 2 ratio of HY zeolite catalysts, which can be ascribed to increase of acid strength with increase of Si/Al 2 ratio. Selectivities to 1-butene, trans-2-butene, and cis-2-butene were not greatly influenced by the change of the Si/Al 2 ratio of HY zeolite. As a result, it was advantageous to use a HY zeolite catalyst with 60 Si/Al 2 ratio for maximizing the yield of 1-butene in the dehydration of 2-butanol. The optimal reaction temperature for maximizing the yield of 1-butene was 250 .deg. C over HY (60) catalyst

A narrative study of novice elementary teachers' perceptions of science instruction

Science.gov (United States)

Harrell, Roberta

It is hoped that, once implemented, the Next Generation Science Standards (NGSS) will engage students more deeply in science learning and build science knowledge sequentially beginning in Kindergarten (NRC, 2013). Early instruction is encouraged but must be delivered by qualified elementary teachers who have both the science content knowledge and the necessary instructional skills to teach science effectively to young children (Ejiwale, 2012, Spencer, Vogel, 2009, Walker, 2011). The purpose of this research study is to gain insight into novice elementary teachers' perceptions of science instruction. This research suggests that infusion of constructivist teaching in the elementary classroom is beneficial to the teacher's instruction of science concepts to elementary students. Constructivism is theory that learning is centered on the learner constructing new ideas or concepts built upon their current/past knowledge (Bruner, 1966). Based on this theory, it is recommended that the instructor should try to encourage students to discover principles independently; essentially the instructor presents the problem and lets students go (Good & Brophy, 2004). Discovery learning, hands-on, experimental, collaborative, and project-based learning are all approaches that use constructivist principles. The NGSS are based on constructivist principles. This narrative study provides insight into novice elementary teachers' perceptions of science instruction considered through the lens of Constructivist Theory (Bruner, 1960).

Dielectron production in proton-proton an proton-deuteron collisions at 1-5 GeV

International Nuclear Information System (INIS)

Titov, A.I.; Kaempfer, B.; Bratkovskaya, E.L.

1994-03-01

Estimates of elementary cross sections for dielectron production in pN and pd reactions are presented. We use throughout the vector dominance model for all hadron-hadron-photon vertices. Dynamical suppression mechanisms (e.g., mass dependent Δ production rate, and the correct energy dependence of the two-body T matrix) bring the elementary rate near to experimental data and previous estimates which do not use vector meson dominance. The Δ, η Dalitz decays and bremsstrahlung appear as dominant sources of dielectrons. Bremsstrahlung is dealt within an improved soft photon approximation which also applies for the pp collisions. Relying on a realistic deuteron wave function we also estimate the energy dependence of the ratio of dielectron yields in pd to pp reactions and find qualitative agreement with new experimental results. (orig.)

Cooperative Learning in Elementary Schools

Science.gov (United States)

Slavin, Robert E.

2015-01-01

Cooperative learning refers to instructional methods in which students work in small groups to help each other learn. Although cooperative learning methods are used for different age groups, they are particularly popular in elementary (primary) schools. This article discusses methods and theoretical perspectives on cooperative learning for the…

Marketing School Music: It's Elementary.

Science.gov (United States)

Anderson, Jill Kuespert

1992-01-01

Explores methods of promoting elementary school music programs. Suggests inviting visitors to the class as a means of increasing awareness of school music. Recommends sending press releases to school newsletters and local newspapers. Reminds teachers to make use of educational access channels on area cable television systems. (SG)

The school nutrition program's role in weight management of 4th grade elementary students

Science.gov (United States)

We are attempting to uncover the school nutrition program's role in weight management of 4th grade elementary students. Data was collected within a time frame for the food frequency questionnaire (FFQ) set at two months at the WT Cheney Elementary School and South Wood Elementary for 4th grade stud...

In-Service Elementary Teachers' Understanding of Magnetism Concepts before and after Non-Traditional Instruction

Science.gov (United States)

Atwood, Ronald K.; Christopher, John E.; Combs, Rebecca K.; Roland, Elizabeth E.

2010-01-01

Magnetism is a topic frequently studied in elementary schools. Since magnetism is a popular topic and is included in national science education standards, it might be assumed that elementary teachers have a good understanding of this topic and that elementary students develop a good understanding of fundamental magnetism concepts. Unfortunately,…

BlenX-based compositional modeling of complex reaction mechanisms

Directory of Open Access Journals (Sweden)

Judit Zámborszky

2010-02-01

Full Text Available Molecular interactions are wired in a fascinating way resulting in complex behavior of biological systems. Theoretical modeling provides a useful framework for understanding the dynamics and the function of such networks. The complexity of the biological networks calls for conceptual tools that manage the combinatorial explosion of the set of possible interactions. A suitable conceptual tool to attack complexity is compositionality, already successfully used in the process algebra field to model computer systems. We rely on the BlenX programming language, originated by the beta-binders process calculus, to specify and simulate high-level descriptions of biological circuits. The Gillespie's stochastic framework of BlenX requires the decomposition of phenomenological functions into basic elementary reactions. Systematic unpacking of complex reaction mechanisms into BlenX templates is shown in this study. The estimation/derivation of missing parameters and the challenges emerging from compositional model building in stochastic process algebras are discussed. A biological example on circadian clock is presented as a case study of BlenX compositionality.

Professional Learning for Cultural Mathematics in Papua New Guinea's Elementary Schools

Science.gov (United States)

Owens, Kay; Edmonds-Wathen, Cris; Kravia, Geori; Sakopa, Priscilla

2014-01-01

A design of principles for teacher professional learning was developed to improve the teaching of "Cultural Mathematics" in elementary schools in Papua New Guinea. The design's appropriateness for PNG elementary schools is the focus of the research implemented through week-long workshops using technology enhancement. Implementation has…

49 CFR 37.27 - Transportation for elementary and secondary education systems.

Science.gov (United States)

2010-10-01

... 49 Transportation 1 2010-10-01 2010-10-01 false Transportation for elementary and secondary education systems. 37.27 Section 37.27 Transportation Office of the Secretary of Transportation... elementary and secondary education systems. (a) The requirements of this part do not apply to public school...

CONSULT-I Reading. South Avondale Elementary School, Cincinnati Project. Final Report.

Science.gov (United States)

Newman, Anabel; And Others

A study examined the effectiveness of the second year of implementation of the CONSULT-I program, which uses artificial intelligence with statistical pattern recognition in constructing a diagnosis and recommending treatment of reading difficulties. Five elementary classroom teachers, two ESEA (Elementary and Secondary Education Act) teachers, and…

Elementary Teachers' Experiences and Perceptions of Departmentalized Instruction: A Case Study

Science.gov (United States)

Strohl, Alecia; Schmertzing, Lorraine; Schmertzing, Richard

2014-01-01

This case study investigated elementary teachers' experiences and perceptions during a trial year of departmentalized instruction in a rural south Georgia elementary school. To inform their decision about whole-school departmentalization for the future, school administrators appointed twelve first through third grade teachers to pilot the…

'Thoroughly Good Football': Teachers and the Origins of Elementary School Football.

Science.gov (United States)

Kerrigan, Colm

2000-01-01

Discusses the origins of elementary school soccer (football), addressing topics such as: the role of public schools in organized soccer, soccer in elementary schools, the first schoolboy soccer association, South London Schools' Football Association, the London Schools' Football Association, and the English Schools' Football Association. (CMK)

Relationships between Static and Dynamic Balance and Anticipation Time, Reaction Time in School Children at the Age of 10-12 Years

Science.gov (United States)

Bozkurt, Sinan; Erkut, Oya; Akkoç, Orkun

2017-01-01

The aim of this study is to investigate the relationship between anticipation time, reaction time and balance characteristics in school children at the age of 10-12 years. 11 males and 12 females, 23 students in total, studying at Istanbul Sancaktepe Ibn-i Sina Elementary School, whose average age was 11.06 years, average height was 142.78 cm and…

π0 decay branching ratios of 5ΛHe and 12ΛC hypernuclei

International Nuclear Information System (INIS)

Okada, S.; Ajimura, S.; Aoki, K.; Banu, A.; Bhang, H.C.; Fukuda, T.; Hashimoto, O.; Hwang, J.I.; Kameoka, S.; Kang, B.H.; Kim, E.H.; Kim, J.H.; Kim, M.J.; Maruta, T.; Miura, Y.; Miyake, Y.; Nagae, T.; Nakamura, M.; Nakamura, S.N.; Noumi, H.; Okayasu, Y.; Outa, H.; Park, H.; Saha, P.K.; Sato, Y.; Sekimoto, M.; Takahashi, T.; Tamura, H.; Tanida, K.; Toyoda, A.; Tsukada, K.; Watanabe, T.; Yim, H.J.

2005-01-01

We precisely measured π0 branching ratios of 5 Λ He and 12 Λ C hypernuclei produced via the (π+,K+) reaction. Using these π0 branching ratios with the π- branching ratios and lifetimes, we obtained the π0 decay widths and the non-mesonic weak decay widths with an accuracy of ∼5% (stat) for both hypernuclei

Preservice Elementary Teachers' Ideas About Scientific Practices

Science.gov (United States)

Ricketts, Amy

2014-10-01

With the goal of producing scientifically literate citizens who are able to make informed decisions and reason critically when science intersects with their everyday lives, the National Research Council (NRC) has produced two recent documents that call for a new approach to K-12 science education that is based on scientific practices, crosscutting concepts, and disciplinary core ideas. These documents will potentially influence future state standards and K-12 curricula. Teachers will need support in order to teach science using a practices based approach, particularly if they do not have strong science backgrounds, which is often the case with elementary teachers. This study investigates one cohort (n = 19) of preservice elementary teachers' ideas about scientific practices, as developed in a one-semester elementary science teaching methods course. The course focused on eight particular scientific practices, as defined by the National Research Council's A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (2012). Participants' written reflections, lesson plans and annotated teaching videos were analyzed in fine detail to better understand their ideas about what it means to engage in each of the practices. The findings suggest that preservice elementary teachers hold promising ideas about scientific practices (such as an emphasis on argumentation and communication between scientists, critical thinking, and answering and asking questions as the goal of science) as well as problematic ideas (including confusion over the purpose of modeling and the process of analysis, and conflating argumentation and explanation building). These results highlight the strengths and limitations of using the Framework (NRC 2012) as an instructional text and the difficulties of differentiating between preservice teachers' content knowledge about doing the practices and their pedagogical knowledge about teaching the practices.

Sheaves in Elementary Mathematics: The case of positive integer numbers

OpenAIRE

Luna-Torres, Joaquin

2015-01-01

We aim to use the concept of sheaf to establish a link between certain aspects of the set of positive integers numbers, a topic corresponding to the elementary mathematics, and some fundamental ideas of contemporary mathematics. We hope that this type of approach helps the school students to restate some problems of elementary mathematics in an environment deeper and suitable for its study.

On the ontology of the elementary particles. A philosophical analysis of the actual elementary-particle physics; Zur Ontologie der Elementarteilchen. Eine philosophische Analyse der aktuellen Elementarteilchenphysik

Energy Technology Data Exchange (ETDEWEB)

Brueckner, Thomas Christian

2015-07-01

After a description of the standard model of elementary-particle physics the author describes structuralistic reconstructions. Then the problem of the theoretical terms is discussed. Therafter the reconstruction of the standard-model elementary particles is described. Finally the ontology of leptons, quarks and both free and in atoms bound protons is considered.

Reaction between uranium hexafluoride and trimethylsilylhalides

Energy Technology Data Exchange (ETDEWEB)

Brown, D; Berry, J A [UKAEA Atomic Energy Research Establishment, Harwell. Chemistry Div.; Holloway, J H; Staunton, G M [Leicester Univ. (UK). Dept. of Chemistry

1938-07-01

Reactions involving 1.1:1 molar ratios of uranium hexafluoride to either trimethylsilylchloride or trimethylsilylbromide in halocarbon solutions yield ..beta..-UF/sub 5/ at room temperature. With 2 mol equivalents of trimethylsilylchloride the product is UF/sub 4/. The reactions appear to proceed via the intermediate formation of unstable brown uranium(VI) chloride and bromide fluorides. Calculations show that UClF/sub 5/ and UCl/sub 2/F/sub 4/ are thermodynamically unstable with respect to the loss of chlorine at room temperature.

Digital Photography for Elementary Students

Science.gov (United States)

Neckers, Matt

2009-01-01

Most elementary students approach photography in an open-minded, experimental way. As a result, their images are often more playful than those taken by adults. Students discover more through their own explorations than they would learn through overly structured lessons. In this article, the author describes how he introduces his elementary…

Elementary Algebra Connections to Precalculus

Science.gov (United States)

Lopez-Boada, Roberto; Daire, Sandra Arguelles

2013-01-01

This article examines the attitudes of some precalculus students to solve trigonometric and logarithmic equations and systems using the concepts of elementary algebra. With the goal of enticing the students to search for and use connections among mathematical topics, they are asked to solve equations or systems specifically designed to allow…

Study of the antineutrino-induced elastic semi-leptonic neutral current reaction

International Nuclear Information System (INIS)

Racca, C.

1978-01-01

A study of the elastic neutral current reaction antiνsub(μ)p→antiνsub(μ)p has been done using Gargamelle filled with propane and the antineutrino beam of the CERN P.S. The space-time structure of the weak neutral current is discussed, the predictions of various V-A models for the ratio of neutral to charged current elastic cross-sections Rsup(antiν) are given. The experimental set-up, the scanning criteria and the program of reconstruction are described. The background due to the contamination by the reaction np→np principally is studied. Cuts are defined to resorbe these backgrounds and corrections are made for other backgrounds and losses. The results are compared with those of the reaction antiνsub(μ)p→μ + n and the ratio Rsup(antiν) is calculated. An upper limit of this ratio is given and the results are discussed [fr

Abnormal reaction of 2,5-Dimethylfuran

International Nuclear Information System (INIS)

Pevzner, L.M.; Ignat'ev, V.M.

1987-01-01

The authors have shown that the expected hydroxymethylation at position 3 of the furan ring does not occur in the reaction of 2,5-dimethylfuran with paraform in acetic acid at 70-80 0 C with the dimethylfuran and paraform in molar ratios of 2:1-1:2, but the products from substitution in the side chain are formed. By vacuum distillation of the reaction mass the authors isolated 2-(5-methyl-2-furyl)- ethanol and a hygroscopic viscous product melting at 136 0 C (5 mm Hg). The yield of the reaction products depends on the molar ratio of the dimethylfuran and paraform. The PMR spectrum of the product contains signals for the β-protons of the furan ring with chemical shifts of 5.81 and 5.90 ppm, a signal for the methyl group in the furan ring at 2.22 ppm, a doublet at 3.72 ppm with spin-spin coupling constant of 6 Hz, a weak quintet at 3.20 ppm with the same constant, and a broadened signal in the region of 4.66 ppm for the proton of the hydroxyl group

Are elementary school teachers prepared to tackle bullying? : A pilot study

NARCIS (Netherlands)

Oldenburg, Beau; Bosman, Rie; Veenstra, Rene

The aim of this pilot study was to investigate to what extent elementary school teachers were prepared to tackle bullying. Interview data from 22 Dutch elementary school teachers (M age=43.3, 18 classrooms in eight schools) were combined with survey data from 373 students of these teachers (M

Elementary particle physics at the University of Florida. Annual progress report

International Nuclear Information System (INIS)

1996-01-01

This report discusses the following topics: Task A: theoretical elementary particle physics; Task B: experimental elementary particle physics; Task C: axion project; Task G: experimental research in collider physics; and Task S: computer acquisition. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database

A Multi-Method Investigation of Mathematics Motivation for Elementary Age Students

Science.gov (United States)

Linder, Sandra M.; Smart, Julie B.; Cribbs, Jennifer

2015-01-01

This paper presents the results of a multi-method study examining elementary students with high self-reported levels of mathematics motivation. Second- through fifth-grade students at a Title One school in the southeastern United States completed the Elementary Mathematics Motivation Instrument (EMMI), which examines levels of mathematics…

Cooperation in Japan. Grades Kindergarten-Third. Elementary Literature Series, Part 1.

Science.gov (United States)

Mukai, Gary

The Stanford Program on International and Cross-Cultural Education (SPICE) represents a long-term effort by Stanford University to improve international and cross-cultural education in elementary and secondary schools. This volume of the elementary literature series focuses on the primary grades; utilizes primary source literature from Japan;…

Elementary affine $lambda$-calculus with multithreading and side effects

OpenAIRE

Madet, Antoine; Amadio, Roberto M.

2011-01-01

Linear logic provides a framework to control the complexity of higher-order functional programs. We present an extension of this framework to programs with multithreading and side effects focusing on the case of elementary time. Our main contributions are as follows. First, we provide a new combinatorial proof of termination in elementary time for the functional case. Second, we develop an extension of the approach to a call-by-value $lambda$-calculus with multithreading and side effects. Thi...

Exploring elementary students’ understanding of energy and climate change

Directory of Open Access Journals (Sweden)

Colin BOYLAN

2008-10-01

Full Text Available As environmental changes become a significant societal issue, elementary science curriculaneed to develop students’ understanding about the key concepts of energy and climate change.For teachers, developing quality learning experiences involves establishing what theirstudents’ prior understanding about energy and climate change are. A survey was developed toexplore what elementary students know and understand about renewable and non-renewablesources of energy and their relationship to climate change issues. The findings from thissurvey are reported in this paper.

Exploring possible reaction pathways for the o-atom transfer reactions to unsaturated substrates catalyzed by a [Ni-NO2 ] ↔ [Ni-NO] redox couple using DFT methods.

Science.gov (United States)

Tsipis, Athanassios C

2017-07-15

The (nitro)(N-methyldithiocarbamato)(trimethylphospane)nickel(II), [Ni(NO 2 )(S 2 CNHMe)(PMe 3 )] complex catalyses efficiently the O-atom transfer reactions to CO and acetylene. Energetically feasible sequence of elementary steps involved in the catalytic cycle of the air oxidation of CO and acetylene are proposed promoted by the Ni(NO 2 )(S 2 CNHMe)(PMe 3 )] ↔ Ni(NO 2 )(S 2 CNHMe)(PMe 3 ) redox couple using DFT methods both in vacuum and dichloromethane solutions. The catalytic air oxidation of HC≡CH involves formation of a five-member metallacycle intermediate, via a [3 + 2] cyclo-addition reaction of HC≡CH to the Ni-N = O moiety of the Ni(NO 2 )(S 2 CNHMe)(PMe 3 )] complex, followed by a β H-atom migration toward the C α carbon atom of the coordinated acetylene and release of the oxidation product (ketene). The geometric and energetic reaction profile for the reversible [Ni( κN1-NO 2 )(S 2 CNHMe)(PMe 3 )] ⇌ [Ni( κO,O2-ONO)(S 2 CNHMe)(PMe 3 )] linkage isomerization has also been modeled by DFT calculations. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Linear free energy relationships between aqueous phase hydroxyl radical reaction rate constants and free energy of activation.

Science.gov (United States)

Minakata, Daisuke; Crittenden, John

2011-04-15

The hydroxyl radical (HO(•)) is a strong oxidant that reacts with electron-rich sites on organic compounds and initiates complex radical chain reactions in aqueous phase advanced oxidation processes (AOPs). Computer based kinetic modeling requires a reaction pathway generator and predictions of associated reaction rate constants. Previously, we reported a reaction pathway generator that can enumerate the most important elementary reactions for aliphatic compounds. For the reaction rate constant predictor, we develop linear free energy relationships (LFERs) between aqueous phase literature-reported HO(•) reaction rate constants and theoretically calculated free energies of activation for H-atom abstraction from a C-H bond and HO(•) addition to alkenes. The theoretical method uses ab initio quantum mechanical calculations, Gaussian 1-3, for gas phase reactions and a solvation method, COSMO-RS theory, to estimate the impact of water. Theoretically calculated free energies of activation are found to be within approximately ±3 kcal/mol of experimental values. Considering errors that arise from quantum mechanical calculations and experiments, this should be within the acceptable errors. The established LFERs are used to predict the HO(•) reaction rate constants within a factor of 5 from the experimental values. This approach may be applied to other reaction mechanisms to establish a library of rate constant predictions for kinetic modeling of AOPs.

Written narrative practices in elementary school students.

Science.gov (United States)

Romano-Soares, Soraia; Soares, Aparecido José Couto; Cárnio, Maria Silvia

2010-01-01

Promotion of a written narratives production program in the third grade of an Elementary School. To analyze two written narrative practice proposals in order to verify which resources are more efficient in benefitting the textual productions of third grade Elementary School students. Sixty students were selected from two third grade groups of a public Elementary School in São Paulo (Brazil). For the analysis, students were divided into two groups (Group A and Group B). Fourteen children's storybooks were used. In Group A, the story was orally told by the researchers in a colloquial manner, keeping the narrator role and the original structure proposed by the author. In Group B, the story was fully read. The book was projected onto a screen and read aloud so the students could follow the reading and observe the corresponding illustrations. Voice changing resources in the characters' dialogues were used. In the overall comparison, statistically significant results were found for moment (initial and final assessments) and for interaction between groups. It was observed that both groups presented substantial development from initial to final assessment. The Written Narratives Promotion Program based on the shared reading of children's storybooks constituted a more effective strategy than telling the stories using a single reader.

Preparation of natural isovaleraldehyde by the Maillard reaction

Institute of Scientific and Technical Information of China (English)

Hong Yu Tian; Jie Zhang; Bao Guo Sun; Ming Quan Huang; Jian Rong Li; Xiao Xiang Han

2007-01-01

Isovaleraldehyde possesses malty, fruity, cocoa-like odor and is widely used in fruit, chocolate, coffee flavors. The preparation of natural isovaleraldehyde by the Maillard model reaction was studied in this paper. The effects of the ratio of D-glucose/L-leucine,reaction temperature and pH value on the yield of isovaleraldehyde were explored. The optimum conditions were as follows:n(D-glucose):n(L-leucine) = 4, temperature 150 ℃, reaction time 3 h, pH 5. The highest yield of isovaleraldehyde obtained was about 32%.

Effects of chemical reaction on moving isothermal vertical plate with variable mass diffusion

Directory of Open Access Journals (Sweden)

Muthucumaraswamy R.

2003-01-01

Full Text Available An exact solution to the problem of flow past an impulsively started infinite vertical isothermal plate with variable mass diffusion is presented here, taking into account of the homogeneous chemical reaction of first-order. The dimensionless governing equations are solved by using the Laplace - transform technique. The velocity and skin-friction are studied for different parameters like chemical reaction parameter, Schmidt number and buoyancy ratio parameter. It is observed that the veloc­ity increases with decreasing chemical reaction parameter and increases with increasing buoyancy ratio parameter.

Examining LGBTQ-Based Literature Intended for Primary and Intermediate Elementary Students

Science.gov (United States)

Bickford, John H., III

2018-01-01

This content analysis research examined how lesbian, gay, bisexual, transsexual, transgender, and queer (LGBTQ) individuals and issues are represented in elementary-level trade books. The data pool included every LGBTQ-based trade book with intended audiences of primary (grades K-2) and intermediate (grades 3-5) elementary students. Trade books…

A Phenomenological Examination of Antisocial Behaviors in the Elementary School Workplace

Science.gov (United States)

Morton, Cynthia

2010-01-01

Antisocial behavior has a direct impact on the public elementary school setting. While considerable research has been conducted on collegiality in postsecondary schools, this study addressed the gap in practice concerning the lack of attention in regard to the impact of antisocial behavior on collegial relationships in the elementary school…

Using Citizen Science to Engage Preservice Elementary Educators in Scientific Fieldwork

Science.gov (United States)

Scott, Catherine M.

2016-01-01

Preservice elementary teachers' lack of confidence in teaching science is an ongoing concern. Only 29% of elementary teachers in the field felt "very well prepared to teach life science," according to the National Survey of Science and Mathematics Education. Research has suggested that bridging informal and formal science education can…

The Predictors of Internet Addiction Behaviours for Taiwanese Elementary School Students

Science.gov (United States)

Lan, Chu M.; Lee, Yu H.

2013-01-01

Although there has been considerable research which has explored factors related to internet addiction, few studies have investigated elementary school students' involvement in this behaviour pattern. Participants in the present study were 1045 children in grades 3 to 6 from elementary schools in Taiwan. Students completed surveys on their use of…

Integrating E-Books into Science Teaching by Preservice Elementary School Teachers

Science.gov (United States)

Lai, Ching-San

2016-01-01

This study aims to discuss the issues of integrating e-books into science teaching by preservice elementary school teachers. The study adopts both qualitative and quantitative research methods. In total, 24 preservice elementary school teachers participated in this study. The main sources of research data included e-books produced by preservice…

The Effects of Note-Taking Skills Instruction on Elementary Students' Reading

Science.gov (United States)

Chang, Wan-Chen; Ku, Yu-Min

2015-01-01

The authors investigated the effects of a 5-week note-taking skills instructional program on note-taking and reading comprehension performance of elementary students. The participants included 349 fourth-grade students from 2 elementary schools in Taiwan. The Note-Taking Instruction group received approximately 40 min of note-taking skills…

The Vulnerability of Urban Elementary School Arts Programs: A Case Study

Science.gov (United States)

Shaw, Ryan D.

2018-01-01

With the intent of improving understanding of cuts to elementary arts programs, the purpose of this research was to investigate how one urban school district (Lansing School District in Lansing, Michigan) eliminated its elementary arts specialists. Research questions were (1) What policy conditions enabled the Lansing School District's decision to…

Innovation in the Elementary Classroom

Science.gov (United States)

Wright, Geoffrey A.; Jones, Matthew D.

2018-01-01

In this article, the authors outline an innovation curriculum that can be taught to elementary-aged students to expand their creative and innovative abilities and potential. The curriculum focuses on divergent and convergent thinking principles embedded in a hands-on learning pedagogy. The curriculum framework is based on an innovation model known…

Atomic nucleus and elementary particles

International Nuclear Information System (INIS)

Zakrzewski, J.

1976-01-01

Negatively charged leptons and hadrons can be incorporated into atomic shells forming exotic atoms. Nucleon resonances and Λ hyperons can be considered as constituents of atomic nuclei. Information derived from studies of such exotic systems enriches our knowledge of both the interactions of elementary particles and of the structure of atomic nuclei. (author)

Thomas Edison Accelerated Elementary School.

Science.gov (United States)

Levin, Henry M.; Chasin, Gene

This paper describes early outcomes of a Sacramento, California, elementary school that participated in the Accelerated Schools Project. The school, which serves many minority and poor students, began training for the project in 1992. Accelerated Schools were designed to advance the learning rate of students through a gifted and talented approach,…

Math Is Like a Lion Hunting a Sleeping Gazelle: Preservice Elementary Teachers' Metaphors of Mathematics

Science.gov (United States)

Latterell, Carmen M.; Wilson, Janelle L.

2016-01-01

Preservice elementary teachers hold a variety of beliefs about mathematics and mathematics learning, which influence their teaching. Previous research has shown that preservice elementary teachers believe that mathematics is doing arithmetic. However, it is unclear if preservice elementary teachers truly believe that mathematics is only…

Maillard reaction products from chitosan-xylan ionic liquid solution.

Science.gov (United States)

Luo, Yuqiong; Ling, Yunzhi; Wang, Xiaoying; Han, Yang; Zeng, Xianjie; Sun, Runcang

2013-10-15

A facile method is reported to prepare Maillard reaction products (MRPs) from chitosan and xylan in co-solvent ionic liquid. UV absorbance and fluorescence changes were regarded as indicators of the occurrence of Maillard reaction. FT-IR, NMR, XRD and TG were used to investigate the structure of chitosan-xylan conjugate. The results revealed that when chitosan reacted with xylan in ionic liquid, the hydrogen bonds in chitosan were destroyed, the facts resulted in the formation of chitosan-xylan MRPs. Moreover, when the mass ratio of chitosan to xylan was 1:1, the Maillard reaction proceeded easily. In addition, relatively high antioxidant property was also noted for the chitosan-xylan conjugate with mass ratio 1:1. So the obtained chitosan-xylan MRP is a promising antioxidant agent for food industry. Copyright © 2013 Elsevier Ltd. All rights reserved.

Recovery processes in the elementary cells of the bone marrow after radiation exposure

International Nuclear Information System (INIS)

Fliedner, T.M.; Steinbach, K.H.; Raffler, H.

1977-01-01

The task of this investigation was to represent the conception of the haematpoietic elementary cell population and their physiological regeneration under conditions of physiological equilibrium and haemopoiesis. Furthermore, the question was dealt with on which factors the recreation processes in the elementary cell storage depend, after a whole or partial body irradiation. Finally, the problem of the recreation processes in the elementary cell storage after chronicle irradiation is discussed. (orig./AJ) [de

Gel/Space Ratio Evolution in Ternary Composite System Consisting of Portland Cement, Silica Fume, and Fly Ash.

Science.gov (United States)

Wu, Mengxue; Li, Chen; Yao, Wu

2017-01-11

In cement-based pastes, the relationship between the complex phase assemblage and mechanical properties is usually described by the "gel/space ratio" descriptor. The gel/space ratio is defined as the volume ratio of the gel to the available space in the composite system, and it has been widely studied in the cement unary system. This work determines the gel/space ratio in the cement-silica fume-fly ash ternary system (C-SF-FA system) by measuring the reaction degrees of the cement, SF, and FA. The effects that the supplementary cementitious material (SCM) replacements exert on the evolution of the gel/space ratio are discussed both theoretically and practically. The relationship between the gel/space ratio and compressive strength is then explored, and the relationship disparities for different mix proportions are analyzed in detail. The results demonstrate that the SCM replacements promote the gel/space ratio evolution only when the SCM reaction degree is higher than a certain value, which is calculated and defined as the critical reaction degree (CRD). The effects of the SCM replacements can be predicted based on the CRD, and the theological predictions agree with the test results quite well. At low gel/space ratios, disparities in the relationship between the gel/space ratio and the compressive strength are caused by porosity, which has also been studied in cement unary systems. The ratio of cement-produced gel to SCM-produced gel ( G C to G S C M ratio) is introduced for use in analyzing high gel/space ratios, in which it plays a major role in creating relationship disparities.

Measurement and analysis of reaction rate distributions of cores with spectrum shifter region

International Nuclear Information System (INIS)

Matsuura, Shigekazu; Shiroya, Seiji; Unesaki, Hironobu; Takeda, Toshikazu; Aizawa, Otohiko; Kanda, Keiji.

1995-01-01

A study for the neutronic characteristics of the spectrum-controlled neutron irradiation fields using various reflector materials was performed. Spectrum shifter regions were constructed in the upper reflector region of the solid moderated core (B-Core) of the Kyoto University Critical Assembly (KUCA). Beryllium, graphite and aluminum were selected as the loading materials for the spectrum shifter. Two tight-pitch lattice cores with different moderator-to-fuel volume ratio (V m /V f ) of 0.97 and 0.65 have been used. Axial reaction rate distributions of gold, nickel and indium wires were measured, and the spectrum index was defined as the Cd ratio of the gold wire and the ratio of gold reaction rate to nickel reaction rate. Using the conventional design calculation procedure, the experimental and calculated reaction rate and spectrum index show several disagreements. Detailed treatment of the neutron streaming effect, heterogeneous cell structure and depression factor are shown to be necessary for improving the agreement between experimental and calculated values. (author)

Introduction to the elementary particle physics

International Nuclear Information System (INIS)

Shellard, R.C.

1982-03-01

An introduction is given to the subject of elementary particle physics. Several particle properties are discussed and some models are shown. This introduction covers the theoretical as well as the experimental aspects including a topic on detectors. (L.C.) [pt

About limit masses of elementary particles

International Nuclear Information System (INIS)

Ibadova, U.R.

2002-01-01

The simple examples of spontaneous breaking of various symmetries for the scalar theory with fundamental mass have been considered. Higgs' generalizations on 'fundamental masses' that was introduced into the theory on a basis of the five-dimensional de Sitter space. The connection among 'fundamental mass', 'Planck's mass' and 'maxim ons' has been found. Consequently, the relationship among G-gravitational constant and other universal parameters can be established. The concept the mass having its root from deep antiquity (including Galilee's Pis sans experiment, theoretical research of the connection of mass with the Einstein's energy etc.) still remains fundamental. Every theoretical and experimental research in classical physics and quantum physics associated with mass is of step to the discernment of Nature. Besides of mass, the other fundamental constants such as Planck's constant ℎ and the speed of light also play the most important role in the modern theories. The first one related to quantum mechanics and the second one is related to the theory of relativity. Nowadays the properties and interactions of elementary particles can be described more or less adequately in terms of local fields that are affiliated with the lowest representations of corresponding compact groups of symmetry. It is known that the mass of any body is composed of masses of its comprising elementary particles. The mass of elementary particles is the Casimir operator of the non-compact Poincare group, and those representations of the given group, that are being used in Quantum Field Theory (QFT), and it can take any values in the interval of 0≤m≤∞. Two particles, today referred to as elementary particles, can have masses; distinct one from another by many orders. For example, vectorial bosons with the mass of ∼10 15 GeV take place in general relativity theory modules, whereas the mass of an electron is only ∼0.5·10 3 GeV. Formally, the standard QFT remains logical in a case

Delivering Technological Literacy to a Class for Elementary School Pre-Service Teachers in South Korea

Science.gov (United States)

Kwon, Hyuksoo

2017-01-01

This study was conducted with the aim of creating a new introductory course emphasizing the development of technological literacy for elementary school pre-service teachers. This study also aimed to investigate elementary school pre-service teachers' attitudinal transition toward elementary school technology education (ESTE) and its…

Elementary Statistics Tables

CERN Document Server

Neave, Henry R

2012-01-01

This book, designed for students taking a basic introductory course in statistical analysis, is far more than just a book of tables. Each table is accompanied by a careful but concise explanation and useful worked examples. Requiring little mathematical background, Elementary Statistics Tables is thus not just a reference book but a positive and user-friendly teaching and learning aid. The new edition contains a new and comprehensive "teach-yourself" section on a simple but powerful approach, now well-known in parts of industry but less so in academia, to analysing and interpreting process dat

Elementary matrix theory

CERN Document Server

Eves, Howard

1980-01-01

The usefulness of matrix theory as a tool in disciplines ranging from quantum mechanics to psychometrics is widely recognized, and courses in matrix theory are increasingly a standard part of the undergraduate curriculum.This outstanding text offers an unusual introduction to matrix theory at the undergraduate level. Unlike most texts dealing with the topic, which tend to remain on an abstract level, Dr. Eves' book employs a concrete elementary approach, avoiding abstraction until the final chapter. This practical method renders the text especially accessible to students of physics, engineeri

A Survey of Greek Elementary School Students' Smoking Habits and Attitudes

Science.gov (United States)

Piperakis, Stylianos M.; Karagouni-Areou, Fotini; Triga, Anastasia; Piperakis, Alexander S.; Argyracouli, Efthimia; Thanou, Aggeliki; Papadimitriou, Basiliki; Gourgoulianis, Konstantinos; Zafiropoulou, Maria

2007-01-01

The purpose of this study was to investigate the smoking habits of Greek elementary school students, their attitudes towards smoking, and their perceptions of the health consequences of tobacco use. Data were obtained from 1,092 elementary school students who completed a 24-item questionnaire designed for this study. Results indicated more older…

Minimum Energy Pathways for Chemical Reactions

Science.gov (United States)

Walch, S. P.; Langhoff, S. R. (Technical Monitor)

1995-01-01

Computed potential energy surfaces are often required for computation of such parameters as rate constants as a function of temperature, product branching ratios, and other detailed properties. We have found that computation of the stationary points/reaction pathways using CASSCF/derivative methods, followed by use of the internally contracted CI method to obtain accurate energetics, gives useful results for a number of chemically important systems. The talk will focus on a number of applications to reactions leading to NOx and soot formation in hydrocarbon combustion.

Development trend of low bypass ratio turbofan engines. Tei baipasu hi tabo fan engine no kaihatsu doko

Energy Technology Data Exchange (ETDEWEB)

Yashima, S [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

1994-03-10

As a turbojet engine gets a thrust by blowing out the exhaust of a gas generator, for decreasing the fuel consumption ratio is more advantageous when a bypass air quantity is made as much as possible. Therefore in the subsonic speed passenger aircrafts putting an economy in the first place, the high bypass ratio turbofan engines are used. Even in case of the subsonic speed aircrafts, in addition, for the trainer airplanes and fighters, a type to be built in the engines in the fuselages, the low bypass ratio engines with small front areas are used. When a turbofan engine with a low bypass ratio is picked up, therefore recently, it is general that a military engine with a bypass ratio under 1 (about 0.5 is frequent) is pointed, as for a development trend also from a viewpoint of the performance improvement as a military engine, an improvement of the thrust-weight ratio and specific thrust are attached importance to. In this paper, these performance parameters, a trend to make them lighter weight, and the elementary technologies peculiar to a low bypass ratio engine are described, and moreover the study and development state in Europe, America and Japan are put in order. 8 refs., 14 figs., 2 tabs.

A research Program in Elementary Particle Physics

Energy Technology Data Exchange (ETDEWEB)

Sobel, Henry; Molzon, William; Lankford, Andrew; Taffard, Anyes; Whiteson, Daniel; Kirkby, David

2013-07-25