Determination of Thermomagnetic Current by Using Neutron Released from Deuterium–Tritium Fusion Reactions in Hybrid Reactors

It is proposed to use the neutrons released from a Deuterium–Tritium fusion reaction to drive thermomagnetic currents in a plasma corona surrounding the fusion plasma through the heating of the corona with nuclear reactions by the neutrons released in the fusion reaction because the fusion reaction cross sections are larger for slow neutrons, it is proposed to slow them down in a moderator separated from the hot plasma of the corona, giving the configuration a similarity to a heterogeneous nuclear fission reactor. While in a fission reactor the separation makes possible a growing neutron chain reaction, it here makes possible the autocatalytic amplification of the thermomagnetic currents by an increase of the fusion reaction rate through a rise of the plasma pressure by the magnetic pressure of the thermomagnetic currents. This is expected to substantially increase the product nτ over its Lawson value.     

Stable isotope characterization of olive oils: II-deuterium distribution in fatty acids studied by nuclear magnetic resonance (SNIF-NMR)

Site-specific isotope fractionation of hydrogen was investigated, at natural abundance, by deuterium nuclear magnetic resonance (SNIF-NMR) on nearly two hundred olive oil samples. Owing to the complexity of the ²H-NMR spectra of the mixtures of fatty acids obtained after hydrolysis of the oils, the different signals were gathered into six clusters. Knowing the contribution to the clusters of each of the four fatty acids considered (C_16:0, C_18:0, C_18:1, and C_18:2) and the composition of the fatty acids in the mixture, it is possible to compute the site-specific isotope ratios of the clusters from the molar fractions obtained from the ²H-NMR-spectra and from the total isotope ratio of the mixture, determined by isotope ratio mass spectrometry (IRMS). The results are discussed in terms of geographical (country, region and elevation) and temporal (year) parameters and they are tentatively explained on a climatic basis.     

Determination of site-specific D/H isotope ratios of glycerol from different sources by 2H-NMR spectroscopy

 A method was developed for the preparation of glycerol from wines and from naturally occuring lipids. In addition, the D/H isotopic ratios of glycerol from these sources was determined using site specific natural isotopic fractionation. Glycerol from four different sources was examined: glycerol isolated from vegetable oils and animal fats, glycerol obtained by chemical synthesis and glycerol which is a byproduct of the alcoholic fermentation of grape musts. Depending on the origin of the glycerol, different isotopic ratios were found; these can be used for the detection of adulterated food or as proof of the authenticity of a given product, such as wine. Received: 13 May 1998     

Effect of plate aspect ratio on the recovery of deuterium from water-isotope mixture in flat-plate thermal diffusion columns with transverse sampling streams

The optimal plate aspect ratios for the best recovery of deuterium from water-isotope mixture in flat-plate thermal diffusion columns with transverse sampling streams have been determined. The maximum recovery and maximum production rate are achieved without changing the total expenditure, while the design with minimum plate surface area results in minimizing the total expense.     

Recovery of deuterium from water-isotopes mixture by thermal diffusion

Methods for theoretical prediction of deuterium recovery from the separation of water-isotope mixtures in a batch-type thermal diffusion column have been introduced. Theoretical predictions are found in fair agreement with the experimental results. Most of the predictions give higher values of separation than experiments. Predictions based on the constant and linear approximations for the pseudo product form of concentration are very similar and have better agreement with experiments than those based on the third type of approximation.     

Dynamic and kinetic modeling of isotopic transient responses for CO insertion on Rh and Mn–Rh catalysts

Isotopic transient tracer techniques have been employed to study heterogeneous hydroformylation on Rh/SiO₂ and Mn–Rh/SiO₂. Pulse injection of D₂ and allowed tracing of the deuterium and CO incorporation pathway into the aldehyde product. The d₁- and d₂-propionaldehyde responses showed a double-peak, or two-hump, response to the D₂ pulse, while showed a single-hump response to the pulse. Analysis of the product responses to the D₂ pulse in CO/H₂/C₂H₄ and CO/H₂/C₂H₄/C₂H₅CHO suggests that the first hump of the d₁- and d₂-propionaldehyde responses was due to rapid H/D exchange with adsorbed propionaldehyde via enol intermediates. The decay of the second hump was due to reaction of adsorbed acyl with spillover hydrogen/deuterium. The response was due to CO insertion followed by acyl hydrogenation. Compartment modeling of the product responses from the and D₂ pulse inputs allowed determination of residence times of adsorbed intermediates, surface coverages of adsorbed intermediates, and the elementary rate constants for acyl hydrogenation and CO insertion. Elementary rate constants for acyl hydrogenation determined from this study were consistent with the value calculated by transition state theory (TST). The addition of Mn promoter to Rh/SiO₂ increased coverages of , , and and shifted the rate-limiting step for propionaldehyde formation. Acyl hydrogenation is the rate-limiting step on Rh/SiO₂ while CO insertion and acyl hydrogenation are both kinetically significant on Mn–Rh/SiO₂.     

APPLICATION OF SITE-SPECIFIC NATURAL ISOTOPE FRACTIONATION (SNIF-NMR) OF HYDROGEN TO THE CHARACTERIZATION OF EUROPEAN BEERS

More than one hundred samples of European beers have been investigated by the new SNIF-NMR method which is based on 2H NMR at the natural abundance level and enables site-specific natural isotope fractionation factors in ethanol to be determined. The relative (R) and absolute (D/H)_i, parameters are shown to be characteristic of the country where the beers are brewed and the observed variations are explained in terms of cereal composition, water resource, and manufacturing processing (fermentation, yeast, temperature cycle). These new parameters find analytical and mechanistic applications in the identification of a beer and in the investigation of a fermentation process.     

POSITRON LIFETIME STUDIES ON SYSTEMS OF PALLADIUM FILLED GALVANOSTATICALLY WITH HYDROGEN OR DEUTERIUM

The positron lifetime spectroscopy was used to investigate the electron structures of crystal lattice and its defects in palladium samples filled galvanostatically with hydrogen and deuterium, respectively. The results have indicated that the positron lifetime were all the same between hydrogen and deuterium filled samples in which the positron lifetime τ(?) increased about 10%, corresponding to the volume expansibility after the formation of hydrides PdH or PdD phases during electrolyzing commom water or heavy water with Pd cathode; and Will not change with time in 3 weeks after stopping electrolysis; but could be recovered to 116±1ps, the value in polycrystalline pure palladium, after annealing at high temperature.     

Studies on the Dynamics of D–T Fusion Reaction Based on the Relativistic Equilibrium Velocity Distribution

The Coulomb barrier is in general much higher than thermal energy. Nuclear fusion reactions occur only among few protons and nuclei (i.e., deuterium and tritium) with higher relative energies than Coulomb barrier. It is the equilibrium velocity distribution of these high-energy protons and nuclei that participates in determining the rate of nuclear fusion reactions. In the circumstance it is inappropriate to use the Maxwellian velocity distribution for calculating the nuclear fusion reaction rate. We use the relativistic equilibrium has a reduction factor with respect to that based on the Maxwellian distribution, which factor depends on the temperature, reduced mass and atomic numbers of the studied nuclear fusion reactions. In this paper, we concluded at energy range 10⁵ (keV) ≤ E ≤ 10⁶ (keV), that is smaller than reduced mass energy of deuterium–tritium, m _r c ², the numerical values of R and R _M are not different from each other very much, but by increasing energy near the region of m _r c ² the difference between them are visible, also by increasing energy for example 9 × 10⁶ (keV) ≤ E ≤ 10 × 10⁶ (keV) the difference is obviously more visible. Therefore, we have to use relativistic equilibrium velocity distribution instead of Maxwellian velocity distribution.     

钾掺杂钨合金中气相热充氘的热脱附行为

钾(K)掺杂钨(W)合金已经表现了优异的高温力学性能,成为最有希望的PFMs备选材料之一。为评估氢同位素在W-K合金中的滞留情况,采用放电等离子烧结技术(SPS),制备了纯W及K含量82μg/g的W-K合金,通过气相热充法引入氘(D)元素,考察热脱附行为。研究表明,气相热充氘释放温区从600K延伸至1200K,掺杂K后,D脱附活化能从0.86 eV下降到0.68 eV;纯W样品D滞留量在1×10^-6(原子比)左右,掺杂K后有所提高,但依然大大优于商用ITER级纯W。