Existence Of Nuclei Research Articles

The Capping Theory of Chemical Clusters Based on 12N/14N Series

The genesis of chemical clusters of the transition and main group elements has been established. The base-line for cluster valence electrons has been demarcated with help of capping series. Using the base-line as a reference, the formulas of fragments and clusters were generated.  Also a simple general formula for calculating cluster valence electrons for systems ranging from a single to multi-skeletal element clusters was identified. The concepts of the existence of nuclei in clusters and some having black-holes were well established. The capping principle was extended to the main group and transition elements of the periodic table and a difference between metals and non-metals was discerned. The skeletal elements of clusters whose series have advanced beyond closo baseline level S=4n+2 can be separated into two broad groups, namely those which follow the closo series(nucleus) and those which follow the capping series.

The Capping Theory of Chemical Elements and Clusters Based on 4N Series and Skeletal Numbers

The genesis of chemical clusters of the transition and main group elements has been established. The base-line cluster valence electrons has been demarcated with help of capping series. Using the base-line as a reference, the formulas of fragments and clusters were generated.  Also a simple general formula for cleating cluster valence electrons for systems ranging from a single skeletal element to hundreds of them was identified. In so doing, the single elements of the periodic table were naturally placed into their respective periods. The concepts of the existence of nuclei in clusters and some having black-holes were deeply rooted. A tentative explanation of some clusters having an octahedral geometry but with low cluster valence electron count was put forward.

On the Interpretation of Fossil Nuclei

Although organelle preservation in plant fossils is not novel and well-preserved plant mesofossils have contributed greatly to the understanding of plant evolution, subcellular structures are still a rarity in plant mesofossils. Although it is not easy to explore subcellular structures in plant fossils, related attempts are frequently seen. Among them, some false interpretation requires further inspection. To shed more light on this issue, here I studied Cretaceous charcoalified mesofossils from USA, using LM (light microscopy), SEM (scanning electron microscopy) and TEM (transmission electron microscopy) technologies. My conclusion shows that not all publications reflect the truthful existence of nuclei in plant fossils, and this study may provide a reference for the future research.

Estimating fission-barrier height by the spherical-basis method

A novel method of estimating fission-barrier heights is presented in this paper, in which potential energy surfaces are calculated by using the spherical-basis method. This method is based on the idea of configuration mixing of various spherical states for deformed nuclei, which gave the ground-state nuclear-mass calculation presented by our group [H. Koura, T. Tachibana, M. Uno, and M. Yamada, Prog. Theor. Phys., 113, 305 (2005)]. Under the restriction of symmetric fission, a systematical fission-barrier calculation is performed in the heavy and superheavy nuclear-mass region, and some higher (neighboring |$^{252}$|Fm, known) and lower (neighboring |$^{278}$|Ds, unknown) fission-barrier regions are found in the nuclear-mass chart; the origin of these appearances is discussed in the framework of the spherical-basis method. The calculated nuclei are also located in the unknown neutron-deficient superheavy nuclear-mass region, where nuclear fission determines a limit on the existence of nuclei. Three regions that have relatively high fission barriers are predicted in neutron-deficient regions having neutron numbers of around 126, 184, and 228.

Heaviest Nuclei

Last year we marked a hundred years since, at the meeting of the Manchester Philosophy Society, Ernest Rutherford had declared for the first time that inside an atom there is found a very tiny but extremely dense object (nucleus) that carries almost all the mass of the atom and all its positive charge. Electrons with negative charge and mass about 2,000 times less than that of a hydrogen atom circulate around the nucleus at large distance similar to planets that move around the Sun. All the further studies in the course of the century supported great Rutherford's foresight that opened the first page in nuclear physics. In this brief article we shall deal with the boundaries of the existence of nuclei and atoms (i.e., of chemical elements).

Reproducible cavitation activity in water-particle suspensions

The study of cavitation inception in liquids rarely yields reproducible data, unless special control is taken on the cleanliness of the experimental environment. In this paper, an experimental technique is demonstrated which allows repeatable measurements of cavitation activity in liquid-particle suspensions. In addition, the method is noninvasive: cavitation bubbles are generated using a shock-wave generator, and they are photographed using a digital camera. The cavitation activity is obtained after suitable image processing steps. From these measurements, the importance of the particle's surface structure and its chemical composition is revealed, with polystyrene and polyamide particles generating the highest yields. Further findings are that cavitation nuclei become depleted with an increasing number of experiments, and the existence of nuclei with varying negative pressure thresholds. Finally, a decrease of the cavitation yield is achieved by prepressurization of the suspension-indicating that the cavitation nuclei are gaseous.

Tetrahedral symmetry in ground and low-lying states of exoticA∼110nuclei

Recent theoretical calculations predict a possible existence of nuclei with tetrahedral symmetry: more precisely, the mean-field hamiltonians of such nuclei are symmetric with respect to double point-group Td. In this paper, we focus on the neutron-rich Zirconium isotopes as an example and present realistic mean-field calculations which predict tetrahedral ground-state configurations in 108,110Zr and low-lying excited states of tetrahedral symmetry in a number of N > 66 isotopes. The motivations for focusing on these nuclei, as well as a discussion of the possible experimental signatures of tetrahedral symmetry are also presented.

The three-dimensional morphology and internal structure of clupeid schools as observed using vertical scanning multibeam sonar

Fish schools are known to take a large number of different shapes and dimensions, in such a way that defining a school from its morphology is still an unanswered question. Nevertheless, some school typology and classification has been done successfully in different areas of the world using vertical echo sounding data. This implies that some morphological patterns may correspond to or reflect behavioural specificities. The objective of this paper is to take advantage of the 3D exhaustive observation capabilities of multibeam sonar to extract the morphological and internal characteristics of tropical clupeid schools. The main parameters measured are geometrical properties (overall dimensions, volume, surface, etc.) and relative distribution of densities inside the school (heterogeneity, existence of nuclei, etc.). The main results show that a school is usually formed of one or several nuclei of high density connected by less dense parts, including empty areas (vacuoles). The dimension of these sub-units is highly variable, but remains inside a diameter of 5-20 m. The reliability of these dimensions is evaluated, and some thoughts on the behavioural mechanisms constituting schools are presented.

Existence of nuclei with unusual neutron excess?

A realistic model is suggested based on the quasiparticle Lagrange version of the self-consistent Finite Fermi Systems theory supplemented with the microscopically calculated surface parameters of the Landau–Migdal interaction amplitude. The latter are expressed in terms of the off-shell T-matrix of free NN-scattering and show a strong dependence on the chemical potential of a nucleus under consideration in the drip line vicinity. This effect could result in shifting the neutron drip line position to very large values of the neutron excess.

Superdeformation — An experimental overview

The existence in nuclei of a stable superdeformed shape at high spin has been well established. The increasing number of examples has shown variations in the properties of the superdeformed bands. As each new feature has been explained invariably the next observation has highlighted a new phenomena. The net result has been a rapidly evolving subject which has dramatically increased our understanding of rapidly rotating nuclei. However, the experimentalists are now clearly limited by the efficiency and sensitivity of the current generation of γ-ray arrays. Over the next few years there is the prospect of new spectrometers (GAMMASPHERE in the USA, EUROGAM and EUROBALL in Europe) which will lower the limit of observation of weak cascades by two orders of magnitude. These instruments will clearly give a major new impetus to high spin γ-ray spectroscopy and we can expect even more new discoveries. The results and ideas reviewed in this talk are the fruits of the labours of many colleagues, both experimental and theoretical, from groups in many countries. I gratefully acknowledge many discussions and the use of data before publication. The data on 152Dy, 151Tb, 150Gd and 142Eu were derived from experiments at Daresbury and the analysis was due to P. Fallon, A. Alderson, I. Ali, G. Smith and S. Mullins and D.M. Cullen. The support of the U.K. Science and Engineering Research Council is gratefully acknowledged.

Determination of the effective charge of solar cosmic-ray nuclei using the Earth's magnetic field

Using the Earth magnetic field as an analyzer we are able to determine the upper limit Q of the charge of cosmic ray nuclei in the energy range, where the direct determination is still very difficult or impossible. In our paper we analyse data from the low-altitude Intercosmos 17 satellite obtained after the solar flare of February 13, 1978 by the TP-2 apparatus in the energy range 5 – 20 MeV/nucleon. Our results indicate the existence of nuclei not fully ionised in our energy range, however, the low statistics does not allow us to determine the exact position of the most probable ionisation state. Nevertheless from the comparison of our and other published data at lower energies 0.3 – 5 MeV/nucleon we can conclude that the energy range of not fully ionised nuclei is much wider.

Observations of nuclei in cavitating flows

The present report focuses on the source of the large difference between the theoretical strength of pure liquid [12] and the actual tension that is required to initiate cavitation in technical fluids such as test facilities and natural waters. This discrepancy is commonly explained by the existence of nuclei, either solid particles or vapor and gas bubbles that permit phase transition to take place near equilibrium. The existence of these nuclei, their source and lifetimes have occupied much space in the technical literature for decades [1, 2, 3, 8]. Yet, direct observations of tests in applications to naval hydrodynamics and hydraulic machinery flows has not provided much information about these nuclei. Their existence, however, and their effect on cavitation is in no doubt as is demonstrated by the series of photographs of a propeller that were taken in the 'Vacu-Tank' of NSMB [9] shown in Figure 1. There, addition of 'nucleating' sources to the water by electrolysis clearly increases the number of visible cavitating bubbles on the blade surfaces. The importance of these nuclei has led to the development of several detection and observation techniques [4, 6, 10, 11]. These include the microscopic observation of water samples, the 'coulter counter', 'single particle light scattering', the 'acoustic' techniques for detection of gas bubbles, holograms with microscopic observation of the reconstructed image, and finally the venturi 'liquid quality' meter [11]. Some results of the nuclei number density distribution function N(R) that were accumulated from various sources [6] in different experimental facilities and some open sea measurements are presented in Figure 2. The results include holographic observation in the Caltech HSWT which are found to be mostly solid particles and the Caltech LTWT which are found to be mostly bubbles. This difference in the type of nuclei may explain why is it easier to cavitate the same body in the LTWT (provided that the flow is non-separating) while the liquid in the HSWT can support a certain tension [6]. Note the several orders of magnitude difference in the populations shown and the correspondence between the oceanic acoustic measurements of Medwin [10] that display the population of bubbles and the holographic observations of plankton [5, 13]. It is interesting that some of these facilities are well above the 'natural' levels and it may be inferred that the Vacu-Tank may be well below. Thus, significant 'scaling' errors may occur while applying laboratory results to field cavitation phenomena [1, 2, 3].

Physical laws and the numerical values of fundamental constants

Data which indicate that the existence of nuclei and atoms and also of stars and galaxies is very sensitive to the numerical values of the fundamental constants, i.e., the coupling constants of the four interactions and the constants G, , c, mp, etc., are reviewed. The variation of some constants by a few tens of percent with the other constants remaining unchanged would lead to the disappearance of stable ground states. Possible interpretations of this fact and its connection to some aspects of unified field theory are analyzed.

Possible existence of abnormal nuclear density in nuclei

Neutral pion production is analyzed in ${\ensuremath{\pi}}^{\ensuremath{-}}$ Xe interactions at 9 GeV/c and, under certain assumptions, the possible existence in nuclei of collections of nucleons with abnormal density is indicated.

The interacting boson model

A relatively quick and correspondingly rough procedure is developed to deal with complex nuclear excitations. This procedure exploits the existence in nuclei of collective excitation (phonons) by replacing the many fermion degrees of freedom with fewer boson degrees of freedom. The emerging picture is that of an interacting boson gas. The boson-boson interaction and boson annihilation graphs are explicitly constructed. It is shown that the interacting boson approximation (IBA) gives good results when applied to the structure of 16O. The limitations of the model are briefly discussed.

Freezing Water and Supercooling: Anchor Ice and Frazil Ice

Abstract The supercooling of water in nature occurs more frequently than is generallyknown. It always takes place when still water is in process of being covered with thefirst ice needles. It is of even greater importance when ice formation takes place in running and turbulent water, in which case it represents the necessary conditions for the formation of frazil and anchor ice. The supercooling may be observed by a sensitive thermometer when the bulb is heated before being immersed in the water. The degree of supercooling of still water may be more than 1° C. in a thin surface layer as the author has demonstrated by measuring the temperature by a recording thermopile exposed to radiation from the surface. It is emphasized that the state of supercooling in water is a stable one, the formation of ice being dependent upon the existence of nuclei or solid boundary surfaces from which crystallization will start and from which liberated heat of solidification will flow. This process of thermal conduction needs time.

Freezing Water and Supercooling: Anchor Ice and Frazil Ice

AbstractThe supercooling of water in nature occurs more frequently than is generallyknown. It always takes place when still water is in process of being covered with thefirst ice needles. It is of even greater importance when ice formation takes place in running and turbulent water, in which case it represents the necessary conditions for the formation of frazil and anchor ice. The supercooling may be observed by a sensitive thermometer when the bulb is heated before being immersed in the water. The degree of supercooling of still water may be more than 1° C. in a thin surface layer as the author has demonstrated by measuring the temperature by a recording thermopile exposed to radiation from the surface. It is emphasized that the state of supercooling in water is a stable one, the formation of ice being dependent upon the existence of nuclei or solid boundary surfaces from which crystallization will start and from which liberated heat of solidification will flow. This process of thermal conduction needs time.