Academic literature on the topic 'Electro-nuclear dynamics'

Experimental studies of hypernuclear dynamics, besides being essential for the understanding of strong interactions in the strange sector, have important astrophysical implications. The observation of neutron stars with masses exceeding two solar masses poses a serious challenge to the models of hyperon dynamics in dense nuclear matter, many of which predict a maximum mass incompatible with the data. In this paper, it is argued that valuable new insight can be gained from the forthcoming extension of the experimental studies of kaon electro production from nuclei to include the 208Pb(e,e′K+)Λ208Tl process. A comprehensive framework for the description of kaon electro production, based on factorization of the nuclear cross section and the formalism of the nuclear many-body theory, is outlined. This approach highlights the connection between the kaon production and proton knockout reactions, which will allow us to exploit the available 208Pb(e,e′p)207Tl data to achieve a largely model-independent analysis of the measured cross section.

We review the present status of the theory of high energy reactions with semi-exclusive nucleon electro-production from nuclear targets. We demonstrate how the increase of transferred energies in these reactions opens a completely new window for study of the microscopic nuclear structure at small distances. The simplifications in theoretical descriptions associated with the increase in the energies are discussed. The theoretical framework for calculation of high energy nuclear reactions based on the effective Feynman diagram rules is described in detail. The result of this approach is the generalized eikonal approximation (GEA), which is reduced to the Glauber approximation when nucleon recoil is neglected. The method of GEA is demonstrated in the calculation of high energy electro-disintegration of the deuteron and A=3 targets. Subsequently, we generalize the obtained formulae for A>3 nuclei. The relation of GEA to the Glauber theory is analyzed. Then, based on the GEA framework we discuss some of the phenomena which can be studied in exclusive reactions: nuclear transparency and short-range correlations in nuclei. We illustrate how light-cone dynamics of high-energy scattering emerge naturally in high energy electro-nuclear reactions.

Certain engineering problems concerning safety of the technological operations of the horizontal transportation of nuclear fuel within the enterprises’ sites were considered. Taking into account current trends in the introduction of robotic systems to reduce the impact of hazardous nuclear materials on personnel, the issue of automated control of the movement of the wheeled robotic platform, which can be used for horizontal transportation of nuclear fuel was studied. The major attention was paid to minimizing the transportation loads on nuclear fuel by means of decreasing the accelerations under its horizontal movement on the robotic wheeled transportation platform, which is a separate issue of the comprehensive safety problem of nuclear materials management. The research of horizontal movement safety of nuclear fuel by means of the robotic wheeled platforms was limited to defining transportation accelerations and was performed by computer simulations using mathematical models of dynamics and electro-mechanics. The mathematical model of the robotic transport wheeled platform loaded with nuclear fuel with the on-board accelerometer ensuring the required measurements necessary for an automated safe movement control system was built in the form of the Lagrange equations of the second kind and the electro-mechanics equations of the direct current electric motors. The issue of ensuring smooth running during the displacement of a wheeled platform loaded with nuclear fuel was investigated, since especially in this mode the maximum accelerations are observed, which can lead to nuclear fuel damage. Computer simulation was performed using free Scilab software with open program code. It was demonstrated that due to the proper choice of the time algorithm of the voltage of electric motors, it is possible to ensure a small acceleration during the displacement of a robotic wheeled transport platform loaded with nuclear fuel. The obtained result substantiated the possibility of safe horizontal transportation of nuclear fuel on robotic wheeled platforms within the territories of enterprises, which will significantly reduce the harmful impact of hazardous nuclear materials on industrial personnel.

The theory of heavy ion double charge exchange (DCE) reactions proceeding by effective rank-2 isotensor interactions is presented. Virtual pion–nucleon charge exchange interactions are investigated as the source for induced isotensor interactions, giving rise to the Majorana DCE (MDCE) reaction mechanism. MDCE is of a generic character, proceeding through pairs of complementary (π±,π∓) reactions in the projectile and target nucleus. The dynamics of the elementary processes is discussed, where the excitation of pion–nucleon resonances are of central importance. Investigations of initial and final state ion–ion interactions show that these effects are acting as vertex renormalizations. In closure approximation, well justified by the finite pion mass, the second-order transition matrix elements reduce to pion potentials and effective two-body isotensor DCE interactions, giving rise also to two-body correlations in either of the participating nuclei. Connections to neutrinoless Majorana double beta decay (MDBD) are elucidated at various levels of the dynamics, from the underlying fundamental electro-weak and QCD scales to the physical scales of nuclear MDBD and MDCE physics. It is pointed out that heavy ion MDCE reactions may also proceed by competing electro-weak charge exchange processes, leading to lepton MDCE by electrons, positrons, and neutrinos.

Internet-based system of Space Monitoring Data Center (SMDC) of Skobeltsyn Institute of Nuclear Physics of Moscow State University (SINP MSU) has been developed to predict and analyze radiation conditions in near-Earth space. This system contains satellite measurement databases and operational models and devoted to collect, store and process space weather monitoring data in the near real-time. SMDC operational services acquire data from ACE, SDO, GOES, Electro-L, Meteor-M satellites and use them for forecasting, now-casting and post-casting of space weather factors. This paper is intended to give overview of operational services of SMDC Internet-based system and demonstrate their possibilities and limitations to analyze space weather phenomena and predict radiation and geomagnetic conditions in the near-Earth space during February 14–March 5, 2014. This prolonged period of high level solar and geomagnetic activity demonstrates various manifestations of the space weather: solar proton events, geomagnetic storms and outer radiation belt (RB) dynamics. Solar sources of interplanetary space disturbances and their influence on geomagnetic and radiation state of the Earth’s magnetosphere were described using output coming from SMDC’ Web-based applications. Validation of SMDC’s operational models was performed based on the quality of description of the physical conditions in near-Earth space during space weather events observed from February 14 to March 5, 2014. The advantages and disadvantages of SMDC operational services are illustrated and discussed based on comparison with data obtained from satellites.

Somatic cell nuclear transfer (SCNT) has been utilized to study various genetic and epigenetic contributions of specific biomedical diseases and developmental events by using various donor cell types such as mature lymphocytes, brain tumor cells, and other unique genotypes. Previously, we produced cloned fetuses and offspring derived from SCNT of adult ear skin fibroblasts obtained from a sub-fertile cow harboring an X-autosome translocation as a model to study X-inactivation and chromosome dynamics during female meiosis. The aim of this study was to assess the cloning efficiency of the fibroblasts derived from a cloned calf with the X-autosome translocation t(Xp+;23q-) compared to the original adult fibroblast donor containing the same chromosome translocation. Primary cultures of cells were established in DMEM +15% fetal calf serum (FCS). To serve as nuclear donors, cells at 5-7 passages were cultured for 5 days until confluent. Oocytes matured for 18 h in TCM-199 with hormones were removed of their chromatin, and reconstructed by transfer of donor cells and fusion with two DC pulses (1.2 kV/cm, 15 �s), delivered by a BTX 2000 Electro Cell Minupulator (BTX, Inc., San Diego, CA, USA), in 0.28 M mannitol containing 0.01 mM MgCl2. After 1 h of fusion, the eggs were activated with 5.5 �M ionomycin for 5 min, followed by 11 �g/mL cyclohexamide for 5 h. The eggs were cultured for 9 days in L-SOF at 39�C in a humidified atmosphere of 5% CO2, 5% O2, 90% N2. Chi-square analysis revealed no significant (P > 0.05) differences in the rates of cleavage, blastocyst frequencies, and cell numbers between the 1st and 2nd generation cloned embryos. Cleavage rates were 87.4% and 85.4% for 1st and 2nd generation cloned embryos, respectively. The frequencies of blastocyst development and hatched blastocyst formation on Day 9 were 41.4% (91/220) and 38.7% (92/238), and 26.4% (58/220) and 22.7% (54/238) for the 1st and 2nd generation cloned embryos, respectively. The numbers of total cells and inner cell mass (ICM) cells of Day 9 blastocysts were 183 and 52, respectively, in the 1st generation embryos and 167 and 51 cells in the 2nd-generation cloned embryos. In summary, 2nd generation cloned embryos derived from fibroblasts of a cloned calf with an X-autosome translocated chromosome showed embryo development and cell numbers similar to those of the 1st generation clones. These results demonstrate that serial nuclear transfer does not improve the blastocyst development rate of cloned embryos containing the X-autosome translocation t(Xp+;23q-). This work was funded by OCAG, OMAF, and CRC.

Nuclear fuel cycle scenario studies are used as a prospective analysis tool in order to provide stakeholders with decision aid. Nuclear fuel cycle simulation tools model the deployment of reactor fleets, the mass flows in the fuel cycle, and track the nuclear materials. The CEA has been developing for more than 30 years the nuclear fuel cycle tool COSI. The latest version, COSI7, was designed in order to model dynamic systems of ever-increasing complexity with improved user experience. The new developments include functionalities designed to improve the user experience as well as new physical models and post-processing capabilities. COSI7 supersedes COSI6 as the CEA reference nuclear fuel cycle simulation code starting January 2020.

Abstract A novel conductive polymeric ionic liquid (IL)-Fe3O4 nanocomposite (represented as PIL-Fe3O4) based on inorganic-organic hybrid material was synthesized using two different methods. Nuclear magnetic resonance, Fourier transform infrared, X-ray diffraction, and field emission scanning electron microscopy characterized the structures of IL, Fe3O4 nanoparticles, and PIL-Fe3O4. The electrochemical sensors based on PIL-Fe3O4-modified glassy carbon electrode were fabricated, and each of these nanocomposites was examined for the ability to determine amlodipine besylate (AMD). The electrochemical study of the modified electrodes, as well as its efficiency for the electro-oxidation of AMD, was described in 0.1 M phosphate-buffered solution (pH 7.0) using voltammetric methods. The results exhibit a linear dynamic range from 1 to 500 nM and a detection limit of 0.36 nM. Finally, the modified electrode was used for the determination of AMD in pharmaceutical and biological samples.

The composite operator effective potential is compared with the conventional Dyson–Schwinger method as a calculational tool for (2+1)-dimensional quantum electro-dynamics. It is found that when the fermion propagator ansatz is put directly into the effective potential, it reproduces exactly the usual gap equations derived in the Dyson–Schwinger approach.

Cette thèse, en deux parties distinctes, se concentre sur l'étude de la dynamique moléculaire de H₂ soumis à un champ laser intense. Dans la première partie (chapitres 2 et 3), j’explore le rôle crucial de la corrélation électronique dans le processus d'ionisation simple de la molécule H₂, en utilisant une méthode ab-initio pour résoudre l'équation de Schrödinger dépendant du temps dans l'approximation de Born-Oppenheimer. J’examine différentes configurations géométriques de la molécule, correspondant à différentes distances internucléaires : à l’état d'équilibre, dans une configuration allongée et dans une configuration quasi-dissociée. Cette analyse permet de mieux appréhender les mécanismes fondamentaux impliqués dans l'ionisation de la molécule H₂ en champs laser intenses. Dans la seconde partie (chapitres 4, 5 et 6), je me suis tourné vers le développement d'un modèle semi-classique permettant d’étudier l'ionisation simple et double de la molécule H₂. Ce modèle permet de calculer de manière quasi-analytique les taux d'ionisation, y compris jusqu'à l'explosion coulombienne, tout en intégrant la propagation des paquets d'onde vibrationnels de la molécule dans sa forme neutre et ionisée. J’ai ainsi été en mesure de prendre en compte les effets résultant de la dynamique de vibration des noyaux, ce qui constitue une avancée significative dans la modélisation de la dynamique moléculaire sous l'impact de champs laser suffisamment intenses pour engendrer une ionisation multiple des molécules. Dans le cadre de ma première étude axée sur les interactions électroniques, j’ai modifié le programme « Many Electron Dynamics System », ou MEDYS, afin de pouvoir désactiver adiabatiquement la corrélation électronique. Ce programme, qui est basé sur un algorithme multi-configurationnel dépendant du temps, est issu de plusieurs décennies de travail au sein du groupe du Prof. Nguyen-Dang de l’Université Laval au Canada. En comparant les dynamiques obtenues avec et sans corrélation électronique, j’ai pu sonder les limites et les conséquences de l'approximation SAE, pour « Single Active Electron ». Cette analyse m’a permis de mieux comprendre l'importance de la corrélation électronique dans le processus d'ionisation simple de la molécule H₂. Dans ma seconde étude, j’ai développé un programme entièrement nouveau pour représenter le processus d'ionisation de manière semi-classique tout en tenant compte de la dynamique vibrationnelle. J’ai commencé par étudier l’influence de différentes approximations dans le calcul des vitesses d’ionisation de la molécule, telles que les approximations ADK ou PPT moléculaires, sur les probabilités de première et seconde ionisation, pour différentes longueurs d'onde d’un champ laser pulsé. J’ai également étudié l'impact sur la distribution vibrationnelle non-Franck-Condon formée dans l’ion moléculaire H₂⁺, des différents paramètres de l’impulsion laser, y compris la polarisation linéaire ou circulaire du champ. J’ai intégré la dynamique vibrationnelle dans ce modèle en utilisant une approche de type opérateur fractionné, pour propager les paquets d'onde de H₂ et H₂⁺. En comparant ces résultats avec ceux obtenus en figeant la dynamique nucléaire, j’ai pu confirmer l'importance d'inclure le mouvement des noyaux dans la modélisation de la dynamique d'ionisation moléculaire, en particulier pour des noyaux très légers comme c’est le cas dans la molécule H₂. Enfin, j’ai pu générer et analyser les spectres de distribution d'énergie cinétique des protons, dans le processus de dissociation de la forme ionisée de la molécule et lors de l'explosion Coulombienne. Ces résultats pourraient être précieux pour de futures collaborations avec des chercheurs en physique des plasmas, leur fournissant un outil permettant d’estimer les probabilités d’ionisation simple et double, et les spectres d'énergie cinétique des protons, contribuant ainsi à une meilleure compréhension des phénomènes physiques se produisant dans certains plasmas
This thesis, in two distinct parts, focuses on the study of the molecular dynamics of H₂ subjected to an intense laser field. In the first part (Chapters 2 and 3), I explore the crucial role of electronic correlation in the single ionization process of the H₂ molecule, using an ab-initio method to solve the time-dependent Schrödinger equation in the Born-Oppenheimer approximation. I study different geometric configurations of the molecule corresponding to different internuclear distances: at equilibrium, in an extended configuration, and in a quasi-dissociated configuration. This analysis provides a better understanding of the fundamental mechanisms involved in the ionization of the H₂ molecule in intense laser fields. In the second part (Chapters 4, 5 and 6), I turned to the development of a semiclassical model for the study of single and double ionization of the H₂ molecule. This model allows the quasi-analytical calculation of ionization rates, including up to the Coulomb explosion, while integrating the propagation of vibrational wave packets of the molecule in its neutral and ionized form. This allowed me to take into account the effects resulting from the vibrational dynamics of the nuclei, which represents a significant advance in the modeling of molecular dynamics under the influence of laser fields intense enough to produce multiple ionization of molecules. In my first study of electronic interactions, I modified the program "Many Electron Dynamics System", or MEDYS, to adiabatically deactivate the electronic correlation. This program, based on a time-dependent multi-configuration algorithm, is the result of decades of work in the group of Prof. Nguyen-Dang at Laval University in Canada. By comparing the dynamics obtained with and without electronic correlation, I was able to explore the limits and consequences of the SAE approximation, for "Single Active Electron". This analysis allowed me to better understand the importance of electronic correlation in the single ionization process of the H₂ molecule. In my second study, I developed a new model to represent the ionization process in a semi-classical way, taking into account vibrational dynamics. I started by investigating the influence of different approximations in calculating the ionization rates of the molecule, such as the ADK or PPT molecular approximations, on the first and second ionization probabilities, for different wavelengths of a pulsed laser field. I also studied the influence of different laser pulse parameters, including the linear or circular polarization of the field, on the non-Franck-Condon vibrational distributions formed in the H₂⁺ molecular ion. I have integrated vibrational dynamics into this model, using a split-operator approach to propagate the H₂ and H₂⁺ wave packets. By comparing these results with those obtained by freezing the nuclear dynamics, I was able to confirm the importance of including nuclear motion in the modeling of molecular ionization dynamics, especially for very light nuclei such as in the H₂ molecule. Finally, I was able to generate and analyze proton kinetic energy release spectra during the process of dissociation of the ionized form of the molecule and during the Coulomb explosion. These results could prove useful in future collaborations with plasma physics researchers, providing them with a tool for estimating single and double ionization probabilities and proton kinetic energy spectra, thus contributing to a better understanding of the physical phenomena occurring in certain plasmas

The possibility of directing the course of chemical reactions by photoexcitation of specific modes of nuclear motion, so called mode-selective chemistry, continues to intrigue physicists, chemists and biologists. In this presentation we will address the application of stimulated Raman excitation, coherent anti-Stokes Raman scattering, overtone infrared excitation, laser induced fluorescence and multiphoton ionization techniques to preparation and detection of particular rovibrational states of the parent and product species in photodissociation and reactions of small molecules. Bond- and mode- selective processes in these species arc particularly appealing for both theoretical and experimental studies. This is because they are small enough to allow ab initio calculations of potential surfaces and photodynamics and yet retain the complexity of different vibrational degrees of freedom. However, quantitative comparison with theory requires experiments that prepare reactant molecules in specific initial states to avoid the averaging over different quantum states. Also, it is necessary to determine accurately the populations in the various final quantum states of the photofragments.

This paper discusses theoretical and experimental analyses of the standing harmonic waves through the electro-mechanical impedance spectroscopy (EMIS) and guided surface acoustic waves (SAW) through the guided wave propagation (GWP) analyses. Both EMIS and GWP analyses have been carried out by utilizing piezoelectric wafer active sensors (PWAS) for in situ structural inspection. PWAS has recently been extensively employed in many applications such as nuclear-structural as well as aero-structural health monitoring and non-destructive evaluations (NDE). EMIS method is utilized for high frequency local modal sensing to determine the dynamic characteristics of PWAS bonded on nuclear-structural component for in-situ ultrasonics. Rayleigh waves a.k.a., SAW, were generated in relatively thick isotropic elastic plates. Rayleigh waves have the property of propagating close to the plate surface, with rapid attenuation with depth. The polarization of Rayleigh waves lies in a plane perpendicular to the surface so that the effective penetration depth is less than a wavelength. Rayleigh waves are a high frequency approximation of the first symmetric (S0) and anti-symmetric (A0) Lamb wave modes. As the frequency becomes very high the S0 and the A0 wave speeds coalesce, and both have the same value. This value is exactly the Rayleigh wave speed and becomes constant along the frequency. In the first part of the study, simplified theoretical constrained PWAS-EMIS model is briefly discussed in relatively high frequency range (in MHz order of magnitude) in terms of thickness mode. Analytical predictive thickness mode impedance simulations of PWAS bonded on plate-like host structures are presented in corresponding with the experiments. For the experimental analyses, PWAS transducers are affixed on isotropic elastic plates such as aluminum plate in relatively high thickness and on a rail I-beam. The extent of the agreement between the experimental and analytical EMIS analyses of PWAS in thickness mode is presented. The study is followed with GWP tests through the pitch-catch method. Rayleigh wave signal packets which are generated in the relatively thick plate and a rail I-beam in high frequency region are assessed along with the experimental thickness mode PWAS-EMIS results. The tuning curve of Rayleigh wave is determined to show the tuning effect of the structure thickness on producing a dominant Rayleigh wave mode. The significant usage of the tuned Rayleigh wave mode is essentially discussed for the applications in the in-situ inspection of relatively thick structures such as nuclear power plant structures. The paper ends with summary, conclusions and suggestions for future work.

Over the past years there has been a dramatic increase in the regulatory requirements for low emissions. Renewable energy targets and CO2 emissions markets drive the transition to a cleaner and renewable energy production system. In addition to increasing the overall plant cycle efficiency, there two principal means of the reduction of the CO2 from coal fired power plants: by coal and biomass co-firing and by the capture and long term storage of the CO2 emitted from power plant. Carbon dioxide capture and storage will involve substantial capital investment, accompanied by a significant power plant cycle efficiency penalty, and is not currently available on a fully commercial basis. Co-firing biomass, in comparison with other renewable sources, is the main contributor to technologies meeting the world’s renewable energy target. However, the impact of biomass co-firing on boilers performance and integrity has been modest. Operational problems associated with the deposition and retention of ash materials can and do occur on all the major gas-side components of combustion and boilers. The process occurs over a wide range of flue gas and surface temperatures, and dependent both on the characteristics of the ash and on the design and operation conditions of the furnace and boiler. Development and validation of the predictive models have been hindered significantly by the practical difficulties in the obtaining reliable data from the boilers operated with coal and biomass. Although specialized on–line deposition monitoring and sootblowing control systems are commercially available, but they are based on a very simple estimates of the fouling factors, which results in crude and not reliable approach to optimization of sootblowers operation. In the present paper an alternative approach and a new technique based on electro-optical sensor are demonstrated. The long term experience with the system attached to the furnace wall and capable to move the compact sensor in and out of the furnace, allowing to measure simultaneously deposits thickness and reflectivity, is described in details. Results of our study show that dynamics of both parameters on the operated power unit can be registered simultaneously in real time and then interpreted separately. Experiments have been carried out with different coal types at 575MW unit equipped with CE tangential boiler and 550 Mw equipped with B&W boiler with opposite fired burners. The measurements were performed in different locations of the furnace. It was shown that dynamics of thickness and reflectivity variation just after the wall cleaning activation are quite different. Situations have been registered where changes of reflectivity have a significant impact on heat transfer, comparable and sometimes even greater than that of growing fouling thickness. Technique and device exploited in this study appears to be a very useful tool for sootblowing optimization and, as a result, for improvement of boiler efficiency and reduction of water wall erosion and corrosion in both pulverized coal and co-firing boilers.