Direct Reaction Rate Research Articles

Practical methods for GPU-based whole-core Monte Carlo depletion calculation

Several practical methods for accelerating the depletion calculation in a GPU-based Monte Carlo (MC) code PRAGMA are presented including the multilevel spectral collapse method and the vectorized Chebyshev rational approximation method (CRAM). Since the generation of microscopic reaction rates for each nuclide needed for the construction of the depletion matrix of the Bateman equation requires either enormous memory access or tremendous physical memory, both of which are quite burdensome on GPUs, a new method called multilevel spectral collapse is proposed which combines two types of spectra to generate microscopic reaction rates: an ultrafine spectrum for an entire fuel pin and coarser spectra for each depletion region. Errors in reaction rates introduced by this method are mitigated by a hybrid usage of direct online reaction rate tallies for several important fissile nuclides. The linear system to appear in the solution process adopting the CRAM is solved by the Gauss-Seidel method which can be easily vectorized on GPUs. With the accelerated depletion methods, only about 10% of MC calculation time is consumed for depletion, so an accurate full core cycle depletion calculation for a commercial power reactor (BEAVRS) can be done in 16 h with 24 consumer-grade GPUs.

Bayesian Calibration of Kinetic Parameters in the CH Chemistry Toward Accurate Prompt-NO Modelling

Abstract Significant efforts made by the gas turbine industry have helped reduce nitrogen oxides (NOx) emissions considerably. To meet and surpass the increasingly stringent regulations, accurate and robust thermochemical mechanisms are needed to help design future sub-10 ppm combustion systems. Uncertainty in kinetic modeling, however, can result in large prediction uncertainty and significant discrepancy between models that hinder the identification of promising combustors with confidence. Direct reaction rate measurements are seldom available for some reactions, especially when involving short-lived radicals such as methylidyne, CH. As the main precursor to the prompt-NO formation pathway, its large parametric uncertainty directly propagates through the nitrogen chemistry preventing accurate and precise emissions predictions. Recent independent CH concentration measurements obtained at various operating conditions are used as indirect rate measurements to perform statistical, or Bayesian, calibration. A subset of important reactions in the CH chemistry affecting peak-CH concentration is identified through uncertainty-weighted sensitivity analysis to first constrain the parametric space of this prompt-NO precursor. Spectral expansion provides the surrogate model used in the Markov-Chain Monte Carlo method to evaluate the posterior kinetic distribution. The resulting constrained CH-chemistry better captures experimental measurements while providing smaller prediction uncertainty of a similar order as the uncertainty of the measurements, which can increase the confidence in simulation results to identify promising future low-emissions configurations. For the quasi-steady-state species CH, fuel decomposition reactions leading to CH production are constrained while little impact is observed for intermediate reactions within the CH-chemistry. The reduction in prediction uncertainty results mainly from the constrained correlations between parameters which greatly limit the set of feasible reaction rate combinations. Additional independent direct and indirect measurements would be necessary to further constrain rate parameters in the CH chemistry, but this calibration demonstrates that predictions of radical species can be improved by assimilating enough data.

Nitric Oxide Reacts Very Fast with Hydrogen Sulfide, Alcohols, and Thiols to Produce HNO: Revised Rate Constants.

The chemical reactivity of NO and its role in several biological processes seem well established. Despite this, the chemical reduction of •NO toward HNO has been historically discarded, mainly because of the negative reduction potential of NO. However, this value and its implications are nowadays under revision. The last reported redox potential, E'(NO,H+/HNO), at micromolar and picomolar concentrations of •NO and HNO, respectively, is between -0.3 and 0 V at pH 7.4. This potential implies that the one-electron-reduction process for NO is feasible under biological conditions and could be promoted by well-known biological reductants with reduction potentials of around -0.3 to -0.5 V. Moreover, the biologically compatible chemical reduction of •NO (nonenzymatic), like direct routes to HNO by alkylamines, aromatic and pseudoaromatic alcohols, thiols, and hydrogen sulfide, has been extensively explored by our group during the past decade. The aim of this work is to use a kinetic modeling approach to analyze electrochemical HNO measurements and to report for the first-time direct reaction rate constants between •NO and moderate reducing agents, producing HNO. These values are between 5 and 30 times higher than the previously reported keff values. On the other hand, we also showed that reaction through successive attack by two NO molecules to biologically compatible compounds could produce HNO. After over 3 decades of intense research, the •NO chemistry is still there, ready to be discovered.

Activation of peroxymonosulfate by biochar and biochar-based materials for degrading refractory organics in water: a review.

Water pollution caused by refractory organics has attracted widespread concern in recent years. At this time peroxymonofulfate (PMS) has been widely used to generate sulfate radicals with high reactivity and potential. The direct reaction rate between PMS and organics is very low. However, the activated PMS has a strong oxidizing ability on organics due to its conversion into sulfate radicals. Recently, the free radicals generated by oxidant PMS and catalyst biochar have proven to be an effective species in dealing with refractory organics. In order to enable researchers to better understand the current research status of PMS/biochar, and to promote the development and application of PMS/biochar system, we have written this review. This review in detail described the mechanism of PMS activated by biochar materials, and summarized the influencing factors of refractory organics degradation in the PMS/biochar system. In addition, the active sites of PMS/biochar, the degradation mechanism of refractory organics, and the reusability of biochar catalysts were also discussed. Finally, the concluding remarks and perspectives were made for future research on the PMS/biochar system in the degradation of refractory organics.

Modeling the Mineralization Kinetics of Visible Led Graphene Oxide/Titania Photocatalytic Ozonation of an Urban Wastewater Containing Pharmaceutical Compounds

In a water ozonation process, dissolved organics undergo two reactions at least: direct ozone attack and oxidation with hydroxyl radicals generated from the ozone decomposition. In the particular case of urban wastewater contaminated with pharmaceuticals, competition between these two reactions can be studied through application of gas–liquid reaction kinetics. However, there is a lack in literature about kinetic modeling of ozone processes in water specially in photocatalytic ozonation. In this work, lumped reactions of ozone and hydroxyl radicals with total organic carbon have been proposed. Urban wastewater containing a mixture of eight pharmaceutical compounds has been used to establish the kinetic model that simulates the mineralization process. The kinetic model is based on a mechanism of free radical and molecular reactions and the knowledge of mass transfer, chemical reaction rate constants, and radiation transfer data. According to the model, both single ozonation and photocatalytic ozonation present two distinct reaction periods characterized by the absence and presence of dissolved ozone. In the first period (less than 10 min), pharmaceuticals mainly disappear by direct ozone reactions and TOC variation due to these compounds has been modeled according to gas–liquid reaction kinetics through a lumped ozone-pharmaceutical TOC fast second order reaction. The corresponding rate constant of this reaction was found to change with time from 3 × 105 to 200 M−1 s−1 with Hatta values higher than 0.3. In the second period (nearly 5 h), competition between direct and hydroxyl radical reactions takes place and a kinetic model based on a direct and free radical reaction mechanism is proposed. Main influencing parameters to be known were: Direct ozone reaction rate constant, catalyst quantum yield, and hydroxyl radical scavengers. The first two take values of 0.5 M−1 s−1 and 5 × 10−4 mol·photon−1, respectively, while a fraction of TOC between 10% and 90% that changes with time was found to possess hydroxyl radical scavenger nature.

Oxidation kinetics of 2‐methyl‐1,3‐propanediol to methacrylic acid in a fluidized bed reactor

AbstractMethacrylic acid (MAA) is a specialty monomer for poly methyl methacrylate (PMMA). Partial oxidation of 2‐methyl‐1,3‐propanediol (2MDPO) to MAA is an alternative to commercial technology with fewer process steps, less cost and toxic feedstocks, and longer catalyst lifetime. Here, we evaluated the effect of 2MPDO and oxygen concentrations, reaction temperature, and contact time on product selectivity and 2MPDO conversion over VOCu0.5/Cs(NH4)2PMo12O40. Higher temperature increases selectivity and conversion; MAA selectivity reached 46% at 69% 2MPDO conversion. Higher 2MPDO to O2 ratio favours higher MAA selectivity due to methacrolein (intermediate) oxidation to MAA (a higher ratio favours consecutive oxidation) or lower combustion of MAA to COx. Shorter contact times decrease MAA selectivity. The Mars van Krevelen model characterizes the experimental data better than both the Langmuir‐Hinshelwood or Eley‐Rideal models; The reaction sequence involves both direct and indirect reactions in which 2MPDO reacts to methacrolein (MAC) as an intermediate and then it oxidizes to MAA (indirect) and/or 2MPDO directly oxidizes to MAA but the indirect reaction rate to MAA is 50 times faster than the direct reaction rate. The reaction is first order with respect 2MPDO and oxygen, and the rate‐limiting step is 2MPDO activation on oxidized sites.

Modelling of the NBI contribution to the neutron energy spectra for the ITER Vertical Neutron Camera

The ITER Vertical Neutron Camera (VNC) is a multichannel collimator system designed to measure the neutron emissivity profile and spectra. The energy spectrum measurements of neutrons made by the VNC will contribute to the reconstruction of the ion temperature, fuel ratio, and fast ions' distribution function. In this paper, the results of neutron spectra calculations for the ITER VNC are presented. The developed software allows for the simulation of particle spectra resulting from interaction of suprathermal ions with thermal background plasma. The method relies on direct reaction rate calculation and explicit fusion reaction kinematics modelling. The assessment of the D-T neutron spectra is carried out for D-NBI heated baseline D-T ITER operation scenarios. It is shown that neutron flux resulting from fast (“beam”) D with thermal T ion interaction dominates at En> 16 MeV part of the spectra. Thus, it is possible to assess fuel ratio based on calculated “thermal-thermal” and “beam-thermal” neutron energy spectra. An ability to observe sawtooth-induced mixing via VNC is studied. Lower energy boundary for the observable part of the suprathermal ion distribution is derived.

Studies on the reversible enzyme reaction of rabbit muscle glycogen phosphorylase b using isothermal titration calorimetry

Glycogen phosphorylase enzymes (GP) catalyse reversible reactions; the glucose transfer from glycogen to inorganic phosphate (Pi, phosphorolysis) or the reverse glucose transfer from glucose-1-phosphate (G-1-P) to glycogen (synthesis). Rabbit muscle GPb (rmGPb) was used as a model enzyme to study the reversible enzyme reaction. To follow both directions of this reversible reaction, we have developed a novel isothermal titration calorimetry (ITC) method for the determination of the direct reaction rate. The preference of forward or reverse reaction was ensured by the 0.1 or 10 concentration ratios of G-1-P/Pi, respectively. Substrate specificity was studied using different maltooligosaccharides and glycogen. Based on the KM values, glycogen and 2-chloro-4-nitrophenyl maltoheptaoside (CNP-G7) were found to be analogous substrates, which allowed to optimize the method by taking advantage of the CNP chromophore being detectable in HPLC. In case of CNP-G7, substrate inhibition was observed and characterised by Ki of 23 ± 7 mM. Inhibition of human GP is a promising strategy for the treatment of diabetes. Our ITC measurements have confirmed that caffeine and glucopyranosylidene-spiro-thiohydantoin (GTH), as known GPb inhibitors, inhibit the rmGPb-catalysed reversible reaction in both directions. Ki values obtained in the direction of synthesis (1.92 ± 0.14 mM for caffeine and 11.5 ± 2.0 μM for GTH) have been shown to be in good agreement with the Ki values obtained in the direction of phosphorolysis (4.05 ± 0.26 mM for caffeine and 13.8 ± 1.6 μM for GTH). The higher difference between the inhibition constants of caffeine was explained by the non-competitive mechanism.The described ITC method using the developed experimental design and reaction conditions is suitable for activity measurements of different phosphorylase enzymes on various substrates and is applicable for inhibition studies as well.

Degradation characteristics of two typical N-heterocycles in ozone process: Efficacy, kinetics, pathways, toxicity and its application to real biologically pretreated coal gasification wastewater

Ozonation of pyridine and indole was investigated both in aqueous solution and biologically pretreated coal gasification wastewater (BPCGW). Experimental results showed that the removal of indole was hardly affected by pH value. Direct reaction rate constant of ozone with pyridine increased from 0.18 M−1 s−1 (protonated pyridine) to 3.03 M−1 s−1 (molecular pyridine), and that with molecular indole was 8.6 × 105 M−1 s−1. Seven and five transformation intermediates were observed for pyridine and indole, respectively. Ozonation pathways were proposed as hydroxylation, opening and cleavage of the aromatic ring. It was found that ammonia nitrogen (NH3N) increased by 3.3 mg L−1 in ozone process, suggesting the broken of the CN bonds of pyridine, indole and other N-heterocyclic compounds. In terms of biochemical oxygen demand to chemical oxygen demand (BOD5/COD), toxicity and resazurin dehydrogenase activity (DHA), the biodegradability was improved after ozone treatment, indicating the possibility of ozone combined with biosystem for the treatment of BPCGW. The results of gas chromatograph and mass spectrometry (GC-MS) indicated that primary products during first 10 min might lead to the obstinate toxicity, which was further proved by US Environmental Protection Agency (US-EPA) test. This study would assist in obtaining a better understanding of the application of ozonation pretreatment in BPCGW.

Non-uniqueness of the multi-temperature law of mass action. Application to 2T plasma composition calculation by means of a collisional-radiative model

This work is devoted to the calculation of the composition for a monoatomic plasma (argon in the case presented) for which the assumption of thermal equilibrium is not realized. The plasma composition is obtained from a CR model, taking into account free electrons and a great number of electronic levels of Ar atoms and Ar+ ions. This model is based on a large set of transition probabilities and reaction rate coefficients for radiative processes (spontaneous emission and radiative recombination) and on an extended database of direct and reverse reaction rate coefficients for collisional processes (excitation/de-excitation and ionization/recombination mechanisms). Assuming Maxwellian energy distribution functions for electrons and heavy chemical species, detailed balance equations are determined for all kind of reactions in the frame of the micro reversibility principle. From these balance equations, reverse rate coefficients are calculated as a function of direct reaction rates and of electrons and heavy particles translation temperatures (T e and T h respectively). Particular attention is paid to problematic chemical reactions with electrons involved on one side and only heavy species on the other side such as: Ar + Ar → Ar + Ar+ + e. The detailed balance relations obtained for ionization/recombination processes demonstrate the non-uniqueness of the multi-temperature Saha-Eggert law (i.e. non-uniqueness of the multi-temperature law of mass action). Multi-temperature argon plasma compositions obtained in the present work exhibit abrupt density variations. These sharp variations are characteristic of the transition between the domination of heavy particle reactions (at low temperature) and the predominance of electron collisions (at high temperature).

Effects of pH value and temperature on the initiation, promotion, inhibition and direct reaction rate constants of natural organic matter in ozonation

pH and temperature affect the kinetics of specific reactions of NOM and influence organic contaminants removal in the ozonation process.

One-Group Cross-Section Generation for Monte Carlo Burnup Codes: Multigroup Method Extension and Verification

Allowing Monte Carlo (MC) codes to perform fuel cycle calculations requires coupling to a point depletion solver. In order to perform depletion calculations, one-group cross sections must be provided in advance. This paper focuses on generating accurate one-group cross-section values using Monte Carlo transport codes. The proposed method is an alternative to the conventional direct reaction rate tally approach, which requires substantial computational effort. The method presented here is based on the multigroup approach, in which pregenerated multigroup sets are collapsed with MC calculated flux. In our previous studies, we showed that generating accurate one-group cross sections requires their tabulation against the background cross section (σ0) to account for the self-shielding effect in the unresolved resonance energy range. However, in previous studies, the model used for the calculation of σ0 was simplified by relying on user-specified Bell and Dancoff factors.This work demonstrates that the one-group cross-section values calculated under the previous simplified model assumptions may not always agree with the directly tallied values. More specifically, the assumption is not universally applicable to the analysis of reactor systems with different neutron spectra and may be inaccurate when the number of energy groups is reduced (i.e., from tens of thousands to hundreds of groups). Therefore, the original background cross-section model was extended by implicitly accounting for the Dancoff and Bell factors.The method developed here reconstructs the correct value of σ0 by utilizing statistical data generated within the MC transport calculation by default. The proposed method was implemented in the BGCore code system. The one-group cross-section values generated by BGCore were compared with those tallied directly from the MCNP code. Very good agreement in the one-group cross-section values was observed. The method does not carry any additional computational burden, and it is universally applicable to the analysis of thermal as well as fast reactor systems. Adopting this multigroup methodology, which accounts for self-shielding, allows generation of highly accurate cross sections even if the number of energy groups is significantly reduced (to hundreds versus tens of thousands of groups). This reduction considerably improves the computational efficiency, which makes the analysis of large-scale reactor problems feasible.

Direct numerical simulation and reaction rate modelling of premixed turbulent flames

Direct numerical simulation (DNS) is employed to investigate the flame characteristics and the mean chemical source term ω˙k˜ of hydrogen/air premixed turbulent combustion in the thin reaction zones regime. Three flames with different initial radius and equivalence ratio are considered. The probability density functions (PDFs) of the flame curvature, shape factor and turbulent flame velocity are plotted and compared for different flames. The distributions of the flame curvature and shape factor indicate that the local geometries for both of the flame kernel and planar flame are similar, irrespective of their difference in the global geometry. The modified laminar flamelet PDF (MLF-PDF) shows improvements over the widely used β-PDF for the progress variable distribution. Several closures for the conditional mean reaction rate are integrated with the presumed PDFs and compared with the DNS data. It is demonstrated that the predictions of the first-order reaction rate integrated with the MLF-PDF are satisfactory for H2 but not for the intermediate species OH. The second-order closure integrated with the MLF-PDF is proved to be promising in predicting both of the major and intermediate species.

Reactive Chemical Vapour Deposition of Titanium Carbide from H2-TiCl4 Gas Mixture on Pyrocarbon: A Comprehensive Study

Abstract In Reactive Chemical Vapour Deposition (RCVD), the absence of one element of the deposited carbide in the initial gas phase involves the consumption/conversion of the solid substrate. In this way, the growth of a continuous carbide layer on the substrate requires solid-phase diffusion of the reagent. In this work, a parametric study of the RCVD of titanium carbide from pyrocarbon (PyC) and an H2-TiCl4 mixture has been carried out. Conversion ratio, PyC consumption and carbide layer growth kinetics have been determined at 1000C. The influence of the H2/TiCl4 dilution ratio has been also investigated. The apparent inter-diffusion coefficient of the carbon through the TiC deposited layer and the direct apparent reaction rate were determined from a comparison between simulations based on a Deal-Grove-type model and the experimental results. The study has been completed with FTIR spectrometry analyses of the gases.

Kinetics in a Double Antibody Radioimmunoassay (RIA): Diffussion Control

Competitive protein binding radioimmunoassay (CPB-RIA) is a principal method for quantifying serum C Peptide concentration. The accuracy of this method is critically dependent on factors that influence the reaction between anti-C Peptide antibody (P) with 125I-C Peptide (M). We studied the influence of initial concentration of M, ionic strength, and viscosity on the reaction between M and P. A kinetic model for the the reaction between. Such model adjusts satisfac- torily to the results. Bi-exponential and irreversible kinetics is determined. The results of the viscosity analysis show clear negative influence on the direct reaction rate. The ionic strength shows scarce influence on equilibrium and negligible in- fluence upon the rate constant, which suggests that the variation resulting from the effect of the glycerol addition is not due to the influence of the dielectric constant of the solutions used. The effect of temperature shows activation parameters similar to the viscous flow energy of water, which suggests that the reaction is diffusion-controlled. The value of ΔHo for the immucomplex formation is positive, as is the case with endothermic processes.

Enhancement of Reduction Rate of Iron Ore by Utilizing Iron Ore/Carbon Composite Consisting of Fine Iron Ore Particles and Highly Thermoplastic Carbon Material

Decreasing the thermal reserve zone temperature is believed to increase the energy efficiency of blast furnace iron-making. To do so, either the direct reduction reaction rate or the coke gasification reaction rate must be significantly increased below 1000°C in CO-lean atmosphere. An iron ore/carbon composite (IOC) has been proposed as a new raw material that can enhance the reduction rate of iron ore. In this paper the possibility of the reduction rate enhancement was examined by preparing a kind of ideal IOC sample consisting of nano-sized Fe2O3 particles (10–70 nm in diameter) and a carbon material prepared from a thermoplastic resin. The nano-sized Fe2O3 particles in the IOC sample were surprisingly reduced to Fe in a few minutes at as low as 650°C in an inert atmosphere. This was realized by increasing the interfacial area between the Fe2O3 particles and carbon and by establishing intimate contact between the two. The carbon in the IOC sample was also completely gasified in less than 10 minutes at as low as 750°C in a CO2 atmosphere. The dramatic enhancement of the gasification rate was found to be realized by the enhancement of one of the direct reduction reactions, the reaction between Fe3O4 particles and carbon, by the aid of in-situ XRD measurement. This suggested that the enhancement of both the reduction reaction rate and the gasification reaction rate is realized by the same mechanism. These new findings will give a clue for designing IOC samples applicable to the blast furnace iron-making.

An investigation of the formation of chlorate and perchlorate during electrolysis using Pt/Ti electrodes: The effects of pH and reactive oxygen species and the results of kinetic studies

The characteristics of chlorate (ClO 3 −) and perchlorate (ClO 4 −) formation were studied during the electrolysis of water containing chloride ions (Cl −). The experiments were performed using an undivided Pt/Ti plate electrode under different pH conditions (pH 3.6, 5.5, 7.2, 8.0 and 9.0). ClO 3 − and ClO 4 − were formed during electrolysis in proportion to the Cl − concentration. The generation rates of ClO 3 − and ClO 4 − under acidic conditions (pH 3.6 and 5.5) were lower than in basic pH conditions (pH 7.2, 8.0 and 9.0). However, the pH of the solution did not influence the conversion of ClO 3 − to ClO 4 −. The effects of intermediately formed oxidants on the production of ClO 3 − and ClO 4 − were observed using sodium thiosulfate (Na 2S 2O 3) as the active chlorine scavenger and tertiary butyl alcohol ( t-BuOH) as the hydroxyl radical ( OH) scavenger. The results revealed that electrolysis reactions that involved active chlorine contributed dominantly to ClO 3 − production. The direct oxidation reaction rate of Cl − to ClO 3 − was 13%. The OH species that were intermediately formed during electrolysis were also found to significantly affect ClO 3 − and ClO 4 − production. The key formation pathways of ClO 3 − and ClO 4 − were studied using kinetic model development.

Synthesis, characterization and catalytic activity of easily recyclable zinc oxide nanobundles

A new self-assembly of ZnO nanobundle has been successfully synthesized in this research by thermal decomposition of zinc oxalate at atmospheric pressure without using any catalyst or solvent at moderate temperature. The XRD analysis showed that the synthesized nanobundles are hexagonal wurtzite-type pure polycrystalline zinc oxide and high resolution transmission electron microscope (HR-TEM) analysis showed that the synthesized nanoparticles size was 0–30nm, and increases up to 10–70nm during the bundle formation. To test the catalytic activity of ZnO nanobundles in catalytic ozonation process, 2-ethoxy ethyl acetate (2-EEA) was used as the model organic pollutant. The results show that the presence of ZnO nanobundles in ozonation process could further enhance 39.7% of 2-EEA decomposition and 9.5% of TOC removal. Increase the catalyst loading from 0.2 to 2g/l would increases the removal rate appreciably. Further increase in the catalyst loading could not enhance the removal rate significantly. Since the direct reaction rate constant (kD) was found to be 0.675M−1S−1, implying that ozone is not a potential oxidizing agent for 2-EEA direct oxidation, catalytic ozonation is thus necessitated to accelerate the decomposition of 2-EEA by hydroxyl radicals produced in the catalytic ozonation process. AAS analysis showed that zinc ion was not leached from the catalysts in all experiments. The catalytic reusability was investigated up to four successive cycles and found that the catalytic efficiency was not decreased appreciably. The catalytic recyclability of nanobundles are investigated and compared with other nanoparticles such as ZnO and TiO2-P25, and found that nanobundles are easily recyclable when compared to the above said nanoparticles. It is concluded that the nanobundles are effective and easily recyclable in catalytic ozonation process.

Mineralization of N-methyl-2-pyrolidone by advanced oxidation processes

This study deals with the mineralization of N-methyl-2-pyrolidone (NMP) by ozonation in a semi-batch lab scale reactor. NMP degradation was not inhibited in the presence of hydroxyl scavengers at acidic medium (pH 3), which indicated that the degradation was only due to ozone. The direct reaction rate constant ( k D) was found to be 1.99 M −1 s −1. The Effect of various physicochemical operating conditions for efficient mineralization was investigated. Total organic carbon (TOC) removal was efficient at pH 10 and 34.5% of TOC enhancement was noted when the solution pH increases from 3 to 10, which confirmed that radical induced mineralization was more efficient. The effect of various influent ozone gas dosages shows that 18.4 mg/(l min) was found to be optimum and further increase in the ozone dosage did not enhance the TOC removal rate. When the ozone gas flow rate increases from 100 ml/min to 300 ml/min, the volumetric mass transfer coefficient ( k L a) increased as well. Increase in the reaction temperature from 5 °C to 50 °C enhances the TOC removal rate and the removal rate was not significant above 25 °C. The TOC removal and nitrate formation efficiencies of NMP at various advanced oxidation processes (AOPs) were in the following order UV/O 3 > O 3 > UV/H 2O 2.

Three-body resonant radiative capture reactions in astrophysics

We develop the formalism based on the S-matrix for $3 \to 3$ scattering to derive the direct three-body resonant radiative capture reaction rate. Within this formalism the states, which decay only/predominantly directly into three-body continuum, should also be included in the capture rate calculations. %The results obtained indicate that some theoretical calculations are %incomplete. Basing on the derivation, as well as on the modern experimental data and theoretical calculations concerning $^{17}$Ne nucleus, we significantly update the reaction rate for $^{15}$O($2p$,$\gamma$)$^{17}$Ne process in explosive environment. We also discuss possible implementations for the $^{18}$Ne($2p$,$\gamma$)$^{20}$Mg, $^{38}$Ca($2p$,$\gamma$)$^{40}$Ti, and $^4$He($n\alpha$,$\gamma$)$^{9}$Be reactions.