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Sample records for superheavy elements challenge

  1. Superheavy Elements Challenge Experimental and Theoretical Chemistry

    CERN Document Server

    Zvára, I

    2003-01-01

    When reflecting on the story of superheavy elements, the an experimenter, acknowledges the role, which the predictions of nuclear and chemical theories have played in ongoing studies. Today, the problems of major interest for experimental chemistry are the studies of elements 112 and 114 including their chemical identification. Advanced quantum chemistry calculations of atoms and molecules would be of much help. First experiments with element 112 evidence that the metal is much more volatile and inert than mercury.

  2. Superheavy elements

    CERN Document Server

    Hofmann, S

    1999-01-01

    The outstanding aim of experimental investigations of heavy nuclei is the exploration of spherical 'SuperHeavy Elements' (SHEs). On the basis of the nuclear shell model, the next double magic shell-closure beyond sup 2 sup 0 sup 8 Pb is predicted at proton numbers between Z=114 and 126 and at neutron number N=184. All experimental efforts aiming at identifying SHEs (Z>=114) were negative so far. A highly sensitive search experiment was performed in November-December 1995 at SHIP. The isotope sup 2 sup 9 sup 0 116 produced by 'radiative capture' was searched for in the course of a 33 days irradiation of a sup 2 sup 0 sup 8 Pb target with sup 8 sup 2 Se projectiles, however, only cross-section limits were measured. Positive results were obtained in experiments searching for elements from 110 to 112 using cold fusion and the 1n evaporation channel. The produced isotopes were unambiguously identified by means of alpha-alpha correlations. Not fission, but alpha emission is the dominant decay mode. The measurement ...

  3. Chemistry of superheavy elements

    International Nuclear Information System (INIS)

    Schaedel, M.

    2012-01-01

    The chemistry of superheavy elements - or transactinides from their position in the Periodic Table - is summarized. After giving an overview over historical developments, nuclear aspects about synthesis of neutron-rich isotopes of these elements, produced in hot-fusion reactions, and their nuclear decay properties are briefly mentioned. Specific requirements to cope with the one-atom-at-a-time situation in automated chemical separations and recent developments in aqueous-phase and gas-phase chemistry are presented. Exciting, current developments, first applications, and future prospects of chemical separations behind physical recoil separators ('pre-separator') are discussed in detail. The status of our current knowledge about the chemistry of rutherfordium (Rf, element 104), dubnium (Db, element 105), seaborgium (Sg, element 106), bohrium (Bh, element 107), hassium (Hs, element 108), copernicium (Cn, element 112), and element 114 is discussed from an experimental point of view. Recent results are emphasized and compared with empirical extrapolations and with fully-relativistic theoretical calculations, especially also under the aspect of the architecture of the Periodic Table. (orig.)

  4. Study of Superheavy Elements

    International Nuclear Information System (INIS)

    Hofmann, Sigurd

    2007-01-01

    The nuclear shell model predicts that the next doubly magic shell-closure beyond 208 Pb is at a proton number Z = 114, 120, or 126 and at a neutron number N = 172 or 184. The outstanding aim of experimental investigations is the exploration of this region of spherical 'SuperHeavy Elements' (SHEs). Experimental methods are described, which allowed for the identification of elements produced on a cross-section level of about 1 pb. The decay data reveal that for the heaviest elements, the dominant decay mode is alpha emission, not fission. Decay properties as well as reaction cross-sections are compared with results of theoretical investigations. Finally, plans are presented for the further development of the experimental set-up and the application of new techniques, as for instance the precise mass measurement of the produced nuclei using ion traps. At increased sensitivity, the detailed exploration of the region of spherical SHEs will start, after first steps on the island were made in recent years. (Author)

  5. Chemistry of the superheavy elements.

    Science.gov (United States)

    Schädel, Matthias

    2015-03-13

    The quest for superheavy elements (SHEs) is driven by the desire to find and explore one of the extreme limits of existence of matter. These elements exist solely due to their nuclear shell stabilization. All 15 presently 'known' SHEs (11 are officially 'discovered' and named) up to element 118 are short-lived and are man-made atom-at-a-time in heavy ion induced nuclear reactions. They are identical to the transactinide elements located in the seventh period of the periodic table beginning with rutherfordium (element 104), dubnium (element 105) and seaborgium (element 106) in groups 4, 5 and 6, respectively. Their chemical properties are often surprising and unexpected from simple extrapolations. After hassium (element 108), chemistry has now reached copernicium (element 112) and flerovium (element 114). For the later ones, the focus is on questions of their metallic or possibly noble gas-like character originating from interplay of most pronounced relativistic effects and electron-shell effects. SHEs provide unique opportunities to get insights into the influence of strong relativistic effects on the atomic electrons and to probe 'relativistically' influenced chemical properties and the architecture of the periodic table at its farthest reach. In addition, they establish a test bench to challenge the validity and predictive power of modern fully relativistic quantum chemical models. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  6. The Chemistry of Superheavy Elements

    CERN Document Server

    Schädel, M

    2003-01-01

    The chemistry of transactinide or superheavy elements has reached element 108. Preparations are under way to leap to element 112 and beyond. The current status of this atom-at-a-time chemical research and its future perspectives are reviewed from an experimental point of view together with some of the interesting results from n -rich nuclides near and at the N=162 neutron shell. Experimental techniques and important results enlightening typical chemical properties of elements 104 through 108 are presented in an exemplary way. From the results of these experiments it is justified to place these elements in the Periodic Table of the Elements in to groups 4 through 8, respectively. However, mainly due to the influence of relativistic effects, it is no longer possible to deduce detailed chemical properties of these superheavy elements simply from this position.

  7. Chemical experiments with superheavy elements.

    Science.gov (United States)

    Türler, Andreas

    2010-01-01

    Unnoticed by many chemists, the Periodic Table of the Elements has been extended significantly in the last couple of years and the 7th period has very recently been completed with eka-Rn (element 118) currently being the heaviest element whose synthesis has been reported. These 'superheavy' elements (also called transactinides with atomic number > or = 104 (Rf)) have been artificially synthesized in fusion reactions at accelerators in minute quantities of a few single atoms. In addition, all isotopes of the transactinide elements are radioactive and decay with rather short half-lives. Nevertheless, it has been possible in some cases to investigate experimentally chemical properties of transactinide elements and even synthesize simple compounds. The experimental investigation of superheavy elements is especially intriguing, since theoretical calculations predict significant deviations from periodic trends due to the influence of strong relativistic effects. In this contribution first experiments with hassium (Hs, atomic number 108), copernicium (Cn, atomic number 112) and element 114 (eka-Pb) are reviewed.

  8. Experimental search for superheavy elements

    International Nuclear Information System (INIS)

    Wieloch, A.

    2008-12-01

    This work reports on the experimental search for superheavy elements (SHE). Two types of approaches for SHE production are studied i.e. '' cold '' fusion mechanism and massive transfer mechanism. First mechanism was studied in normal and inverse kinematics, by using Wien filter at the GANIL facility. The production of SHE elements with Z 106 and 108 is reported while negative results on the synthesis of SHE elements with Z 114 and 118 was received. The other approach i.e. reactions induced by heavy ion projectiles (e.g. 172 Yb, 197 Au) on fissile target nuclei (e.g. 238 U, 232 Th) at near Coulomb barrier incident energies was studied by using superconducting solenoid installed Texas A(and)M University. Preliminary results for the reaction 197 Au(7.5 MeV/u) - 232 Th are presented where three cases of the possible candidates for SHE elements were found. A dedicated detection setup for such studies is discussed and the detailed data analysis is presented. Detection of alpha and spontaneous fission radioactive decays is used to unambiguously identify the atomic number of SHE. Special statistical analysis for a very low detected number of α decays is applied to check consistency of the αradioactive chains. (author)

  9. Tests on the synthesis of superheavy elements

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The article briefly summarizes the study of superheavy elements, starting with speculations on the existence of relatively long-living nuclei via theoretical works to nuclear properties and chemical properties, search for the longest-living nuclei of the calculated stability island in nature, up to the attempts to produce such superheavy elements in large heavy ion accelerators (Berkely, Dubna, Darmstadt, Orsay). Principle and problems of the two methods to achieve a synthesis of such heavy nuclei, i. e. fusion reactions and transfer reactions, are briefly discussed. (RB) [de

  10. Silicon vertex detector for superheavy elements identification

    Directory of Open Access Journals (Sweden)

    Bednarek A.

    2012-07-01

    Full Text Available Silicon vertex detector for superheavy elements (SHE identification has been proposed. It will be constructed using very thin silicon detectors about 5 μm thickness. Results of test of 7.3 μm four inch silicon strip detector (SSD with fission fragments and α particles emitted by 252Cf source are presented

  11. Superheavy element chemistry. Achievements and perspectives

    International Nuclear Information System (INIS)

    Schaedel, M.

    2007-01-01

    Superheavy elements have been synthesized and chemically characterized one-atom-at-a-time up to element 108. Presently, the quest for element 112 is one of the hottest topics in this field. The transactinide elements 104 to 108 are members of group 4 to 8 of the Periodic Table and element 112 belongs into group 12. Chemical properties of some of these elements, like elements 104 and 105, show stunning deviations from simple extrapolations within their respective group while others exhibit great similarities with their lighter homologues elements. First experiments to investigate seaborgium (Sg, element 106) in aqueous solution were performed. Again, in large international collaborations at the GSI, several gas-phase chemistry experiments were performed with hassium (Hs, element 108). Recently, the highly efficient and very clean separation of Hs was applied for nuclear studies of various Hs nuclides investigating their cross section and their nuclear decay properties in the region of the doubly-magic 270 Hs (Z=108, N=162). To overcome certain limitations of the presently used on-line chemical separations the new TransActinide Separation and Chemistry Apparatus (TASCA) - with a gas-filled recoil separator as a front-end tool - was designed and built at the GSI in a collaborative effort. Presently in its commissioning phase, TASCA shall be a key instrument for a big leap into quantitatively and qualitatively new experiments in the region of superheavy elements. (author)

  12. Electronic structure and chemical properties of superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Pershina, V [Gesellschaft fuer Schwerionenforschung (GSI), Helmholtzzentrum fuer Schwerionenforschung Gmbh (Germany)

    2009-12-31

    Relativistic electronic structure calculations of superheavy elements (Z>=104) are analyzed. Preference is given to those related to experimental research. The role of relativistic effects is discussed.

  13. The Superheavy Elements and Anti-Gravity

    Science.gov (United States)

    Anastasovski, Petar K.

    2004-02-01

    The essence of any propulsion concept is to overcome gravity. Anti-gravity is a natural means to achieve this. Thus, the technology to pursue anti-gravity, by using superheavy elements, may provide a new propulsion paradigm. The theory of superluminal relativity provides a hypothesis for existence of elements with atomic number up to Z = 145, some of which may possess anti-gravity properties. Analysis results show that curved space-time exists demonstrating both gravitic and anti-gravitic properties not only around nuclei but inside the nuclei as well. Two groups of elements (Z Hawking, in honour of Stephen W. Hawking.

  14. Electronic structure theory of the superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Eliav, Ephraim, E-mail: ephraim@tau.ac.il [School of Chemistry, Tel Aviv University, 6997801 Tel Aviv (Israel); Fritzsche, Stephan, E-mail: s.fritzsche@gsi.de [Helmholtz-Institut Jena, Fröbelstieg 3, D-07743 Jena (Germany); Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universität Jena, D-07743 Jena (Germany); Kaldor, Uzi, E-mail: kaldor@tau.ac.il [School of Chemistry, Tel Aviv University, 6997801 Tel Aviv (Israel)

    2015-12-15

    High-accuracy calculations of atomic properties of the superheavy elements (SHE) up to element 122 are reviewed. The properties discussed include ionization potentials, electron affinities and excitation energies, which are associated with the spectroscopic and chemical behavior of these elements, and are therefore of considerable interest. Accurate predictions of these quantities require high-order inclusion of relativity and electron correlation, as well as large, converged basis sets. The Dirac–Coulomb–Breit Hamiltonian, which includes all terms up to second order in the fine-structure constant α, serves as the framework for the treatment; higher-order Lamb shift terms are considered in some selected cases. Electron correlation is treated by either the multiconfiguration self-consistent-field approach or by Fock-space coupled cluster theory. The latter is enhanced by the intermediate Hamiltonian scheme, allowing the use of larger model (P) spaces. The quality of the calculations is assessed by applying the same methods to lighter homologs of the SHEs and comparing with available experimental information. Very good agreement is obtained, within a few hundredths of an eV, and similar accuracy is expected for the SHEs. Many of the properties predicted for the SHEs differ significantly from what may be expected by straightforward extrapolation of lighter homologs, demonstrating that the structure and chemistry of SHEs are strongly affected by relativity. The major scientific challenge of the calculations is to find the electronic structure and basic atomic properties of the SHE and assign its proper place in the periodic table. Significant recent developments include joint experimental–computational studies of the excitation spectrum of Fm and the ionization energy of Lr, with excellent agreement of experiment and theory, auguring well for the future of research in the field.

  15. A probability of synthesis of the superheavy element Z = 124

    Energy Technology Data Exchange (ETDEWEB)

    Manjunatha, H.C. [Government College for Women, Department of Physics, Kolar, Karnataka (India); Sridhar, K.N. [Government First Grade College, Department of Physics, Kolar, Karnataka (India)

    2017-10-15

    We have studied the fusion cross section, evaporation residue cross section, compound nucleus formation probability (P{sub CN}) and survival probability (P{sub sur}) of different projectile target combinations to synthesize the superheavy element Z=124. Hence, we have identified the most probable projectile-target combination to synthesize the superheavy element Z = 124. To synthesize the superheavy element Z=124, the most probable projectile target combinations are Kr+Ra, Ni+Cm, Se+Th, Ge+U and Zn+Pu. We hope that our predictions may be a guide for the future experiments in the synthesis of superheavy nuclei Z = 124. (orig.)

  16. Electronic structure and properties of superheavy elements

    International Nuclear Information System (INIS)

    Pershina, V.

    2015-01-01

    Spectacular developments in the relativistic quantum theory and computational algorithms in the last few decades allowed for accurate calculations of properties of the superheavy elements (SHE) and their compounds. Often conducted in a close link to the experimental research, these investigations helped predict and interpret an outcome of sophisticated and expensive experiments with single atoms. Most of the works, particularly those related to the experimental studies, are overviewed in this publication. The role of relativistic effects being of paramount importance for the heaviest elements is elucidated.

  17. Mean-field models and superheavy elements

    International Nuclear Information System (INIS)

    Reinhard, P.G.; Bender, M.; Maruhn, J.A.; Frankfurt Univ.

    2001-03-01

    We discuss the performance of two widely used nuclear mean-field models, the relativistic mean-field theory (RMF) and the non-relativistic Skyrme-Hartree-Fock approach (SHF), with particular emphasis on the description of superheavy elements (SHE). We provide a short introduction to the SHF and RMF, the relations between these two approaches and the relations to other nuclear structure models, briefly review the basic properties with respect to normal nuclear observables, and finally present and discuss recent results on the binding properties of SHE computed with a broad selection of SHF and RMF parametrisations. (orig.)

  18. Superheavy Element Synthesis And Nuclear Structure

    International Nuclear Information System (INIS)

    Ackermann, D.; Block, M.; Burkhard, H.-G.; Heinz, S.; Hessberger, F. P.; Khuyagbaatar, J.; Kojouharov, I.; Mann, R.; Maurer, J.; Antalic, S.; Saro, S.; Venhart, M.; Hofmann, S.; Leino, M.; Uusitalo, J.; Nishio, K.; Popeko, A. G.; Yeremin, A. V.

    2009-01-01

    After the successful progress in experiments to synthesize superheavy elements (SHE) throughout the last decades, advanced nuclear structure studies in that region have become feasible in recent years thanks to improved accelerator, separation and detection technology. The means are evaporation residue(ER)-α-α and ER-α-γ coincidence techniques complemented by conversion electron (CE) studies, applied after a separator. Recent examples of interesting physics to be discovered in this region of the chart of nuclides are the studies of K-isomers observed in 252,254 No and in 270 Ds.

  19. On superheavy elements, what did we achieve

    International Nuclear Information System (INIS)

    Armbruster, P.

    1986-03-01

    The properties of the heaviest isotopes are discussed using recent results on α-energies, halflives, and branchings between the different decay modes. From the data on α- and spontaneous fission halflives and absolute masses, fission barriers and barrier widths are deduced. Shell corrections of the heaviest nuclei are obtained and compared to recent calculations. The concept of superheavy elements is examined, and it is shown that the heaviest isotopes known must be classified 'superheavy'. The production cross sections are summarized and within the extra-push model the reduced fusion probabilities in the entrance channel are discussed. It is shown that besides nuclear structure effects in the collision partners are of importance. It is concluded that targets around 208 Pb give a double gain, on the one hand from the fact that fusion is relatively cold (1n- and 2n-channels), and on the other hand that the extra-push limitation is setting in later than the model predicts. The possibilities to make still heavier elements are restricted not by their groundstate instability but by the principal limitations of their production. (orig.)

  20. The Superheavy Elements and Anti-Gravity

    International Nuclear Information System (INIS)

    Anastasovski, Petar K.

    2004-01-01

    The essence of any propulsion concept is to overcome gravity. Anti-gravity is a natural means to achieve this. Thus, the technology to pursue anti-gravity, by using superheavy elements, may provide a new propulsion paradigm. The theory of superluminal relativity provides a hypothesis for existence of elements with atomic number up to Z = 145, some of which may possess anti-gravity properties. Analysis results show that curved space-time exists demonstrating both gravitic and anti-gravitic properties not only around nuclei but inside the nuclei as well. Two groups of elements (Z < 64 and 63 < Z <145) exist that demonstrate these capabilities. The nuclei of the first group of elements have the masses with only the property of gravity. The nuclei of the elements of the second group have the masses with both properties: gravity and anti-gravity in two different ranges of curved space-time around the nuclei.. The hypothetical element with Z = 145 is the unique among all elements whose nucleus has only anti-gravity property. It is proposed that this element be named Hawking, in honour of Stephen W. Hawking

  1. Recent searches for superheavy elements at the superhilac

    International Nuclear Information System (INIS)

    Hulet, E.K.

    1978-01-01

    The results of the search for superheavy elements are negative with respect to the finding of such elements. However, by assuming 2 spontaneous fission events as the lower limit of detection, the limits to their formation cross sections are calculated and plotted. It is noted that the half-life limits, also shown are easily within the huge uncertainties of the theoretical predicted half lives for any superheavy element nuclides produced in the experiment. 19 references

  2. Frontiers of heavy-ion physics and superheavy elements

    International Nuclear Information System (INIS)

    Muenzenberg, G.

    2003-01-01

    This contribution will focus on three topics of GSI nuclear structure research: superheavy elements, direct mass measurements in the storage ring, and studies of fission in reversed kinematics. The GSI project for a new synchrotron facility will be outlined

  3. Synthesis and properties of superheavy elements

    CERN Document Server

    Hofmann, S

    2003-01-01

    The nuclear shell model predicts that the next doubly magic shell-closure beyond sup 2 sup 0 sup 8 Pb is at a proton number Z = 114, 120, or 126 and at a neutron number N = 172 or 184. The outstanding of experimental investigations is the exploration of this region of spherical 'SuperHeavy Elements' (SHEs). Experimental methods are described which allowed for the identification of elements 107 to 112 in studies of cold fusion reactions based on lead and bismuth targets. Also presented are data which were obtained on the synthesis of elements 112, 114, and 116 in investigation of hot fusion reactions using actinide targets. The decay data reveal that for the heaviest elements, the dominant decay mode is alpha emission, not fission. Decay properties as well as reaction cross- sections are compared with the results of theoretical studies. Finally, plans are presented for the further development of the experimental set-up and the application of new techniques. At a higher sensitivity, the exploration of the regio...

  4. Alpha decay properties of heavy and superheavy elements

    International Nuclear Information System (INIS)

    Vigila Bai, G.M. Carmel; Umai Parvathiy, J.

    2015-01-01

    Analysing accurately the lifetimes of α-decay chains is an important tool to detect and study the properties of superheavy nuclei. 48 Ca is used in the synthesis of superheavy nuclei Z = 106-118 at Dubna. The experimental work of 48 Ca projectiles at Dubna has given an opportunity to study the superheavy element (SHE). Here, the α-decay properties for Z = 106-118 are evaluated using our CYE model and are compared with the available experimental and theoretical values. (author)

  5. On the Production of Superheavy Elements

    CERN Document Server

    Armbruster, P

    2003-01-01

    Since the discovery of Deformed Superheavy Nuclei (1983–85) a bridge connects the island of SHE to known isotopes of lighter elements. What we know experimentally and theoretically on the nuclear structure of SHE is reported in a first section. The making of the elements, with an analysis of production cross sections, and the macroscopic limitation to Z=112+ is presented in a second section. The break-down of fusion cross sections in the ‘Coulomb Falls’ within a range of about 10 elements is introduced as the universal limiting phenomenon. How the nuclear structure of the collision partners modifies the on-set of this limitation is presented in Section 3. Reactions induced by deformed nuclei are pushed by side collisions to higher excitation energies (4n- and 5n-channels), whereas reactions driven by the cluster-like, closed-shell nuclei, 208126Pb and 13882Ba, are kept at low excitation energies (1n- and 2n-channels). The on-set of production limitation for deformed collision partners is moved to smalle...

  6. Synthesis and investigation of superheavy elements - perspectives with radioactive beams

    International Nuclear Information System (INIS)

    Muenzenberg, G.

    1997-09-01

    The perspectives for the investigation of heavy and superheavy elements with intense beams of radioactive nuclei available from the new generation of secondary beam facilities in combination with modern experimental developments are the subject of this paper. The nuclear properties of the recently discovered shell nuclei centered at Z=108 and N=164 and predictions on the location of the superheavy region with improved theoretical models will be discussed. (orig.)

  7. Do superheavy elements imply the existence of black holes

    International Nuclear Information System (INIS)

    Pringle, J.E.; Dearborn, D.S.P.; Fabian, A.C.

    1976-01-01

    Some comments are offered on the question of where superheavy elements, such as elements 116, 124 and 126, are likely to have been formed. Most of these elements are thought to have been produced under conditions of explosive nucleosynthesis by what is known as the 'r-process', and particularly in conventional supernova explosions, but it is stated that the ability of the r-process to produce superheavy elements is very uncertain, and the conditions necessary for synthesis of these elements are difficult to realise in astrophysical situations. It is thought that superheavy elements exist in the outer layers of neutron stars, and ideal conditions for the production of superheavy nuclei, such as high neutron flux and rapid β decays, occur in the disruption of a neutron star. Such disruption is possible in two ways, both of which involve a black hole. It is likely that a neutron star is disrupted when it accretes sufficient material for its mass to exceed the maximum mass for stability, and it then has no alternative but to collapse to form a black hole and it seems possible that some of the outer layers are thrown off during the process. It is thus argued that the most likely site for the production of superheavy elements is in the surface layers of a neutron star, and the most plausible means by which these layers can be returned to the interstellar medium involves the intervention or formation of a black hole. (U.K.)

  8. Superheavy Element Synthesis and Nuclear Structure

    International Nuclear Information System (INIS)

    Ackermann, D.

    2009-01-01

    The search for the next closed proton and neutron shells beyond 2 08P b has yielded a number of exciting results in terms of the synthesis of new elements [1,2,3]. The superheavy elements (SHE), however, are a nuclear structure phenomenon. They owe their existence to the quantum mechanical origin of shell correction energies without which they would not be bound. In recent years the development of efficient experimental set-ups including separators and advanced particle and photon detection arrangements allowed for more and more detailed nuclear structure studies for nuclei at and beyond Z=100. A review of those recent achievements is given in ref. [4]. Among the most interesting features is the observation of K-isomeric states. Experimentally about 14 cases have been identified in the region of Z>96 as shown in Fig. 1. K-isomers or indications of their existence have been found for almost all even-Z elements in the region Z=100 to 110. We could recently establish and/or confirm such states in the even-even isotopes 2 52,254N o [5]. The heaviest nucleus where such a state was found is 2 70D s with Z=110 as we reported in 2001 [6]. Those nuclear structure studies lay out the grounds for a detailed understanding of these heavy and high-Z nuclear systems, and contribute at the same time valuable information to preparation of strategies to successfully continue the hunt for the localisation of the next spherical proton and neutron shells after 2 08P b. The recent activities for both SHE synthesis and nuclear structure investigations at GSI will be reported.(author)

  9. Quasifission Dynamics in the Formation of Superheavy Elements

    Directory of Open Access Journals (Sweden)

    Hinde D.J.

    2017-01-01

    Full Text Available Superheavy elements are created through the fusion of two heavy nuclei. The large Coulomb energy that makes superheavy elements unstable also makes fusion forming a compact compound nucleus very unlikely. Instead, after sticking together for a short time, the two nuclei usually come apart, in a process called quasifission. Mass-angle distributions give the most direct information on the characteristics and time scales of quasifission. A systematic study of carefully chosen mass-angle distributions has provided information on the global trends of quasifission. Large deviations from these systematics at beam energies near the capture barrier reveal the major role played by the nuclear structure of the two colliding nuclei in determining the reaction outcome, and thus implicitly in hindering or favouring superheavy element synthesis.

  10. Actinide targets for the synthesis of super-heavy elements

    International Nuclear Information System (INIS)

    Roberto, J.B.; Alexander, C.W.; Boll, R.A.; Burns, J.D.; Ezold, J.G.; Felker, L.K.; Hogle, S.L.; Rykaczewski, K.P.

    2015-01-01

    Since 2000, six new super-heavy elements with atomic numbers 113 through 118 have been synthesized in hot fusion reactions of "4"8Ca beams on actinide targets. These target materials, including "2"4"2Pu, "2"4"4Pu, "2"4"3Am, "2"4"5Cm, "2"4"8Cm, "2"4"9Cf, and "2"4"9Bk, are available in very limited quantities and require specialized production and processing facilities resident in only a few research centers worldwide. This report describes the production and chemical processing of heavy actinide materials for super-heavy element research, current availabilities of these materials, and related target fabrication techniques. The impact of actinide materials in super-heavy element discovery is reviewed, and strategies for enhancing the production of rare actinides including "2"4"9Bk, "2"5"1Cf, and "2"5"4Es are described.

  11. Quasifission in heavy and superheavy element formation reactions

    International Nuclear Information System (INIS)

    Hinde, D.J.; Dasgupta, M.; Jeung, D.Y.; Mohanto, G.; Prasad, E.; Simenel, C.; Walshe, J.; Wahkle, A.; Williams, E.; Carter, I.P.; Cook, K.J.; Kalkal, Sunil; Rafferty, D.C.; Rietz, R. du; Simpson, E.C.; David, H.M.; Düllmann, Ch.E.; Khuyagbaatar, J.

    2016-01-01

    Superheavy elements are created in the laboratory by the fusion of two heavy nuclei. The large Coulomb repulsion that makes superheavy elements decay also makes the fusion process that forms them very unlikely. Instead, after sticking together for a short time, the two nuclei usually come apart, in a process called quasifission. Mass-angle distributions give the most direct information on the characteristics and time scales of quasifission. A systematic study of carefully chosen mass-angle distributions has provided information on the global trends of quasifission. Large deviations from these systematics reveal the major role played by the nuclear structure of the two colliding nuclei in determining the reaction outcome, and thus implicitly in hindering or favouring superheavy element production.

  12. Boiling points of the superheavy elements 117 and 118

    International Nuclear Information System (INIS)

    Takahashi, N.

    2001-01-01

    It has been shown that the relativistic effect on the electrons reveal in the heavy element region. What kind of changes will appear in the heavy elements because of the relativistic effects? Can we observe the changes? We observed that the boiling points of astatine and radon are lower than that extrapolated values from lighter elements in the same groups. Systematic behavior of the elements on the boiling point was examined and a new method for the estimation of the boiling points of the superheavy elements in the halogen and rare gases has been found. The estimated values of the elements 117 and 118 are 618 and 247 K, respectively which are considerably lower than those obtained until now. If these values are correct the production of the superheavy elements with heavy ions reaction may be affected. Further, the chemical properties may be fairly different from the lighter elements. (author)

  13. Recent searches for superheavy elements in deep-inelastic reactions

    International Nuclear Information System (INIS)

    Hulet, E.K.; Lougheed, R.W.; Nitschke, J.M.

    1980-10-01

    New attempts have been made to synthesize superheavy elements (SHE) by nuclear reactions that may possibly form the products at low excitation energies. Survival of the superheavy elements would then be enhanced because of reduced losses from prompt fission. Classical and diffusion-model calculations of deep-inelastic reactions indicate there should be detectable yields of SHE formed with less than 30 MeV of excitation energy. Accordingly, superheavy elements have been sought in such reactions where targets of 248 Cm and 238 U have been irradiated with 136 Xe and 238 U ions. In the most recent experiments, targets of 248 Cm metal (3.5 to 7 mg-cm -2 ) were bombarded with 1.8-GeV 238 U ions from the UNILAC accelerator. The longer-lived SHE and actinides near the target Z were chemically separated, and the yields of a number of isotopes of Bk, Cf, Es, and Fm were measured. An upper limit of 30 nb was obtained for the formation of 1-h 259 No. In addition to the off-line chemical recovery and search for SHE, an on-line experiment was performed to detect volatile SHE with half-lives of a minute or more. All experiments to produce and detect superheavy elements were much less than optimum because of premature failures in the Cm-metal targets. The outcome and status of these experiments and the implications of the actinide yields in estimating the chances for forming superheavy elements in the 248 Cm + 238 U reactions are discussed. 5 figures, 1 table

  14. Beyond darmstadtium -Status and perspectives of superheavy element research

    International Nuclear Information System (INIS)

    Ackermann, D.

    2005-01-01

    The search for superheavy elements has yielded exciting results for both the ''cold fusion'' approach with reactions employing Pb and Bi targets and the ''hot fusion'' reactions with 48 Ca beams on actinide targets. In recent years the accelerator laboratories in Berkeley, Dubna and Darmstadt have been joined by new players in the game in France with GANIL, Caen, and in Japan with RIKEN, Tokyo. The latter yielding very encouraging results for the reactions on Pb/Bi targets which confirmed the data obtained at GSI. Beyond the successful synthesis, interesting features of the structure of the very heavy nuclei like the hint for a possible K-isomer in 270 Ds or the population of states at a spin of up to 22ℎ in 254 No give a flavor of the exciting physics we can expect in the region at the very extreme upper right of the nuclear chart. To get a hand on it, a considerable increase in sensitivity is demanded from future experimental set-ups. High intensity stable beam accelerators, mass measurement in ion traps and mass spectrometers, as well as the possible employment of unstable neutron-rich projectile species, initially certainly only for systematic studies of reaction mechanism and nuclear structure features for lighter exotic neutron-rich isotopes, are some of the technological challenges which have been taken on. (orig.)

  15. Synthesis of superheavy elements by cold fusion

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, S [Gesellschaft fuer Schwerionenforschung (GSI), Helmholtzzentrum fuer Schwerionenforschung Gmbh (Germany)

    2009-12-31

    The nuclear shell model predicts that the next doubly magic shell-closure beyond {sup 208}Pb is at the proton number Z=114, 120, or 126 and at the neutron number N=172 or 184. The outstanding aim of experimental investigations is the exploration of this region of spherical 'Super Heavy Elements' (SHEs). Using cold fusion reactions which are based on lead and bismuth targets, the new elements from 107 to 112 were synthesized at GSI in Darmstadt, Germany. Some of these results were confirmed at RIKEN in Wako, Japan, where also a relatively neutron-deficient isotope of element 113 was synthesized. In hot fusion reactions of {sup 48}Ca projectiles with actinide targets, a more neutron-rich isotope of element 112 and the new elements from 113 to 116 and even 118 were produced at FLNR in Dubna, Russia. Recently, part of these hot fusion data, which represent the first identification of nuclei located on the predicted island of SHEs, were confirmed in two independent experiments. The decay data reveal that for the heaviest elements, the dominant decay mode is alpha emission rather than fission. The decay properties as well as reaction cross-sections are compared with results of theoretical studies.

  16. Superheavy Elements: Theoretical Expectations and Related Fundamental Issues

    International Nuclear Information System (INIS)

    Greiner, W.

    2008-01-01

    I discuss the theory for superheavy elements, based on the Two Center Shell Model. Potential energy surfaces, cold valleys, cold fusion, quasi fusion and other processes will be discussed. The experimental results from GSI, Dubna and Japan are presented. Finally, utilizing the theory of mass-exchange in dynamical encounters by Zagrebaev and myself, I will outline the possibility of long time delays of giant molecular/atomic systems (e.g. U + U, U + Cm, etc) and its relevance for observing the supercritical decay of the QED-vacuum

  17. Superheavy element research at the velocity filter ship

    International Nuclear Information System (INIS)

    Heinz, S.

    2012-01-01

    The Separator for Heavy Ion Reaction Products (SHIP) is a velocity filter located at the UNILAC accelerator of GSI Darmstadt, Germany. For about 35 years a broad experimental program in the field of superheavy element research is running at SHIP. During the last years particularly investigations in the region of the heaviest known nuclei were performed. In fusion reactions of 48 Ca + 248 Cm → 296 116* a total of six decay chains was observed which could be attributed to the evaporation residues 292 116 and 293 116. In this experiment, data measured previously on the same isotopes in Dubna were well confirmed. Besides, two attempts were made to synthesize isotopes of the still unobserved element Z = 120 in reactions of 64 Ni + 238 U and 54 Cr + 248 Cm. No events were observed in these experiments leading to one-event cross-section limits of 90 fb and 560 fb, respectively. For future superheavy element research, a new superconducting continuous wave LINAC is planned at GSI which shall deliver beam intensities of up to 1014 particles per second. In this context we are developing a next generation separator and new detection techniques

  18. Collisions of deformed nuclei and superheavy-element production

    International Nuclear Information System (INIS)

    Iwamoto, Akira; Moeller, P.; Univ. of Aizu, Fukushima; P. Moller Scientific Computing and Graphics, Inc., Los Alamos, NM; Los Alamos National Lab., NM; Nix, J.R.; Sagawa, Hiroyuki, Sagawa

    1995-01-01

    A detailed understanding of complete fusion cross sections in heavy-ion collisions requires a consideration of the effects of the deformation of the projectile and target. The aim here is to show that deformation and orientation of the colliding nuclei have a very significant effect on the fusion-barrier height and on the compactness of the touching configuration. To facilitate discussions of fusion configurations of deformed nuclei, the authors develop a classification scheme and introduce a notation convention for these configurations. They discuss particular deformations and orientations that lead to compact touching configurations and to fusion-barrier heights that correspond to fairly low excitation energies of the compound systems. Such configurations should be the most favorable for producing superheavy elements. They analyze a few projectile-target combinations whose deformations allow favorable entrance-channel configurations and whose proton and neutron numbers lead to compound systems in a part of the superheavy region where a half-lives are calculated to be observable, that is, longer than 1 micros

  19. Relativistic quantum chemistry of the superheavy elements. Closed-shell element 114 as a case study

    International Nuclear Information System (INIS)

    Schwerdtfeger, Peter; Seth, Michael

    2002-01-01

    The chemistry of superheavy element 114 is reviewed. The ground state of element 114 is closed shell [112]7s 2 7p 1/2 2 and shows a distinct chemical inertness (low reactivity). This inertness makes it rather difficult to study the atom-at-a-time chemistry of 114 in the gas or liquid phase. (author)

  20. Upper Limit of the Periodic Table and Synthesis of Superheavy Elements

    Directory of Open Access Journals (Sweden)

    Khazan A.

    2007-04-01

    Full Text Available For the first time, using the heaviest possible element, the diagram for known nuclides and stable isotopes is constructed. The direction of search of superheavy elements is indicated. The Periodic Table with an eighth period is tabulated.

  1. Search for superheavy elements in the bombardment of 248Cm with 48Ca

    International Nuclear Information System (INIS)

    Hulet, E.K.; Lougheed, R.W.; Wild, J.F.; Landrum, J.H.; Stevenson, P.C.; Ghiorso, A.; Nitschke, J.M.; Otto, R.J.; Morrissey, D.J.; Baisden, P.A.; Gavin, B.F.; Lee, D.; Silva, R.J.; Fowler, M.M.; Seaborg, G.T.

    1977-01-01

    We have searched for superheavy elements 110 to 116 with half-lives between 10 4 and 10 8 s in fractions chemically separated after each of a series of bombardments of 248 Cm made with 267-MeV 48 Ca ions. After 6 months of α and spontaneous-fission counting, our results provide no persuasive evidence for the presence of super-heavy elements. The most plausible explanation for not finding the superheavy elements is that they have either short half-lives or very small formation cross sections

  2. Dissipative dynamics of the synthesis of superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Takahiro; Aritomo, Y.; Tokuda, T.; Okazaki, K.; Ohta, M. [Konan Univ., Kobe (Japan). Dept. of Physics; Abe, Y.

    1997-07-01

    Fusion-fission process in heavy systems are analyzed by Smoluchowski equation taking into account the temperature dependent shell correction energy. The evaporation residue cross sections of superheavy elements have been shown to have an optimum value at a certain temperature, due to the balance between the diffusibility for fusion at high temperature and the restoration of the shell correction energy against fission at low temperature. The isotope dependence of the evaporation residue cross section is found to be very strong. Neutron rich compound system with small neutron separation energy is favorable for larger cross section because of the quick restoration of the shell correction energy. The Z-dependence is discussed for the formation of the compound nuclei with Z=102 to Z=114. (author)

  3. Estimation of atomic masses of heavy and superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Uno, Masahiro [Ministry of Education, Science and Culture, Tokyo (Japan)

    1997-07-01

    To estimate unknown atomic masses of heavy and superheavy elements, three kinds of formula: FRDM (finite range droplet model by Moeller et al.), TUYY (an empirical formula by Tachibana et al.) and our KUTY are explained. KUTY estimates the crude shell energies of spherical nucleus from sum of single-particle energies. Then, the refined shell energies in due consideration of paring and deformation are obtained by mixing with the functions of the crude shell energies. Experimental values of U and Fm isotopes were compared with estimation mass of KUTY and FRDM. In the field with experimental values of U isotopes, the value of KUTY and FRDM separated the same difference from the experimental value. The behavior of KUTY and FRDM for Fm isotopes were same as that of U, but ETFSI deviated a little from the experimental values. (S.Y.)

  4. Attempts in search for superheavy elements in nature II

    International Nuclear Information System (INIS)

    Langrock, E.-J.; Vater, P.; Brandt, R.; Langrock, G.; Schumer, F.; Schreck, P.

    1999-01-01

    The search for superheavy elements is continued. We chose minerals for long-time exposure in a sandwich arrangement (PAD [polyallyldiglycol carbonate] and mica). In a first step we investigated samples of manganese concretions from the Pacific Ocean, enriched samples from Salton Sea and a volatile by product - fraction of copper - shale (Kupferschiefer) from Mansfeld ('Theisenschlamm'). After an exposure time of 535 days or 326 days, respectively, and proper etching, the SSNTD's were scanned using an optical microscope. Tracks due to the fission fragments could be seen neither at the PAD nor at the mica surface. The most hopeful sample 'Theisenschlamm' gives about 1.2x10 6 tracks of α-particles at PAD. This can be explained by the uranium content. The exposure will be continued and other samples will be investigated, too

  5. On the way to unveiling the atomic structure of superheavy elements

    International Nuclear Information System (INIS)

    Laatiaoui, Mustapha

    2016-01-01

    Optical spectroscopy of the transfermium elements (atomic number Z > 100) is nowadays one of the most fascinating and simultaneously challenging tasks in atomic physics. On the one hand, key atomic and even nuclear ground-state properties may be obtained by studying the spectral lines of these heaviest elements. On the other hand, these elements have to be produced “online” by heavy-ion induced fusion-evaporation reactions yielding rates on the order of a few atoms per second at most, which renders their optical spectroscopy extremely difficult. Only recently, a first foray of laser spectroscopy into this heaviest element region was reported. Several atomic transitions in the element nobelium (Z = 102) were observed and characterized, using an ultra-sensitive and highly efficient resonance ionization technique. The findings confirm the predictions and additionally provide a benchmark for theoretical modelling. The work represents an important stepping stone towards experimental studies of the atomic structure of superheavy elements.

  6. Superheavy elements in D I Mendeleev's Periodic Table

    Energy Technology Data Exchange (ETDEWEB)

    Oganessian, Yury Ts; Dmitriev, Sergey N [Flerov Laboratory for Nuclear Reactions, Joint Institute for Nuclear Research, Dubna, Moscow Region (Russian Federation)

    2009-12-31

    The results on the synthesis of new superheavy elements, synthesized in complete fusion reactions of {sup 48}Ca ions with actinide targets, are summarized and analyzed. The perspectives for the synthesis of element 117, as well as of elements with Z>=118 are also considered.

  7. Structure of superheavy elements with Meson field theory and beyond

    International Nuclear Information System (INIS)

    Walter Greiner

    2005-01-01

    The extension of the periodic system into various new areas is investigated. Experiments for the synthesis of superheavy elements and the predictions of magic numbers with modern meson field theories are reviewed. Furtheron, different channels of nuclear decay are discussed including cluster radioactivity, cold fission and cold multifragmentation. A perspective for future research is given. We also study the possibility of producing a new kind of nuclear system that in addition to ordinary nucleons contains a few antibaryons. The properties of such systems are described within the relativistic mean-field model by employing G-parity transformed interactions for antibaryons. Calculations are first done for infinite systems and then for finite nuclei from 4 He to 208 Pb. It is demonstrated that the presence of a real antibaryon leads to a strong rearrangement of a target nucleus, resulting in a significant increase of its binding energy and local compression. Noticeable effects remain even after the antibaryon coupling constants are reduced by a factor of 3-4 compared to G-parity motivated values. We have performed detailed calculations of the antibaryon annihilation rates in the nuclear environment by applying a kinetic approach. It is shown that owing to significant reduction of the reaction Q values, the in-medium annihilation rates should be strongly suppressed, leading to relatively long-lived antibaryon- nucleus systems. Multinucleon annihilation channels are analyzed too. We have also estimated formation probabilities of bound antibaryon-nucleus systems in antiproton- nucleus reactions and have found that their observation will be feasible at the future GSI antiproton facility. Several observable signatures are proposed. The possibility of producing cold multi-quark-antiquark clusters is discussed. This opens the possibility for cold compression of nuclear matter - in contrast to the creation of hot and dense nuclear matter in nuclear shock waves created in

  8. Search for superheavy elements in monazite from Beach sands of South India

    International Nuclear Information System (INIS)

    Kapoor, S.S.; Ramamurthy, V.S.; Lal, R.; Kataria, S.K.

    1977-01-01

    Monazite minerals obtained from beach of South India were examined for the presence of superheavy elements with photon-induced x-ray fluorescence method. The accumulated data of a number of runs each of several days duration do not show any convicing peaks above the background at the expected locations for superheavy elements which are above the present sensitivity of detection of about 10 ppm by weight for element 126. However, some intriguing features pertaining to structures in the x-ray spectra around 27 kev were observed, which are of interest for further investigations. (author)

  9. Superheavy-element spectroscopy: Correlations along element 115 decay chains

    Science.gov (United States)

    Rudolph, D.; Forsberg, U.; Sarmiento, L. G.; Golubev, P.; Fahlander, C.

    2016-05-01

    Following a brief summary of the region of the heaviest atomic nuclei yet created in the laboratory, data on more than hundred α-decay chains associated with the production of element 115 are combined to investigate time and energy correlations along the observed decay chains. Several of these are analysed using a new method for statistical assessments of lifetimes in sets of decay chains.

  10. Global and local approaches to population analysis: Bonding patterns in superheavy element compounds

    Science.gov (United States)

    Oleynichenko, Alexander; Zaitsevskii, Andréi; Romanov, Stepan; Skripnikov, Leonid V.; Titov, Anatoly V.

    2018-03-01

    Relativistic effective atomic configurations of superheavy elements Cn, Nh and Fl and their lighter homologues (Hg, Tl and Pb) in their simple compounds with fluorine and oxygen are determined using the analysis of local properties of molecular Kohn-Sham density matrices in the vicinity of heavy nuclei. The difference in populations of atomic spinors with the same orbital angular momentum and different total angular momenta is demonstrated to be essential for understanding the peculiarities of chemical bonding in superheavy element compounds. The results are fully compatible with those obtained by the relativistic iterative version of conventional projection analysis of global density matrices.

  11. New Fragment Separation Technology for Superheavy Element Research

    International Nuclear Information System (INIS)

    Shaughnessy, D A; Moody, K J; Henderson, R A; Kenneally, J M; Landrum, J H; Lougheed, R W; Patin, J B; Stoyer, M A; Stoyer, N J; Wild, J F; Wilk, P A

    2008-01-01

    This project consisted of three major research areas: (1) development of a solid Pu ceramic target for the MASHA separator, (2) chemical separation of nuclear decay products, and (3) production of new isotopes and elements through nuclear reactions. There have been 16 publications as a result of this project, and this collection of papers summarizes our accomplishments in each of the three areas of research listed above. The MASHA (Mass Analyzer for Super-Heavy Atoms) separator is being constructed at the U400 Cyclotron at the Flerov Laboratory of Nuclear Reactions in Dubna, Russia. The purpose of the separator is to physically separate the products from nuclear reactions based on their isotopic masses rather than their decay characteristics. The separator was designed to have a separation between isotopic masses of ±0.25 amu, which would enable the mass of element 114 isotopes to be measured with outstanding resolution, thereby confirming their discovery. In order to increase the production rate of element 114 nuclides produced via the 244 Pu+ 48 Ca reaction, a new target technology was required. Instead of a traditional thin actinide target, the MASHA separator required a thick, ceramic-based Pu target that was thick enough to increase element 114 production while still being porous enough to allow reaction products to migrate out of the target and travel through the separator to the detector array located at the back end. In collaboration with UNLV, we began work on development of the Pu target for MASHA. Using waste-form synthesis technology, we began by creating zirconia-based matrices that would form a ceramic with plutonium oxide. We used samarium oxide as a surrogate for Pu and created ceramics that had varying amounts of the starting materials in order to establish trends in material density and porosity. The results from this work are described in more detail in Refs. [1,4,10]. Unfortunately, work on MASHA was delayed in Russia because it was found that

  12. Fusion-fission dynamics and synthesis of the superheavy elements

    International Nuclear Information System (INIS)

    Abe, Yasuhisa

    2003-01-01

    given by a product of the sticking and the formation probabilities. The former is that for the system to overcome the Coulomb barrier to stick each other, while the latter that for the system to overcome the conditional saddle to form the spherical shape. Residue cross sections for the superheavy elements are predicted by combining the survival probability which is calculated with the statistical theory of decay. Some examples will be presented on Z=110, 111, 112 and 113. (author)

  13. Superheavy Elements and Beyond: - Supercritical Coulomb Field and Giant Quasiatoms

    International Nuclear Information System (INIS)

    Greiner, Walter

    2007-01-01

    The status of theory of Superheavy Nuclei is reviewed. Based with the Two-Center Shell Model Potential Energy Surfaces are calculated. Fusion, fission, quasifission and other processes are discussed. I particular time-delay during the formation of giant quasi atoms/molecules will be crucial for observing the change of the Dirac vacuum in supercritical Coulomb fields by spontaneous positron emission. It will be shown how the various phenomena are interrelated

  14. Some new approaches to the synthesis of heavy and superheavy elements

    International Nuclear Information System (INIS)

    Flerov, G.N.

    1980-01-01

    The results of work on the synthesis of heavy and superheavy elements are considered. It is shown that the new regularity of the systematics of spontaneous-fission half-lives, established for heavy nuclei at Dubna, has made it possible to extend the region of the nuclei being synthesized. In particular, it becomes possible to produce relatively long-lived heavy isotopes of Z>=107. The results of experiments to study the emission of energetic α-particles in the collision of heavy nuclei are presented. It is noted that such reactions can be used to produce atomic nuclei with low excitation energy and large angular momentum. The possible use of similar reactions in the synthesis of heavy and superheavy elements is discussed. In case the existence of a naturally occurring superheavy element has been established, a possibility will arise to synthesize in nuclear reactions a number of isotopes belonging to the island of stability, and to investigate their properties. The present state of work on the search for superheavy elements in nature is briefly described

  15. Mendeleev's principle against Einstein's relativity: news from the chemistry of superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Gaeggeler, Heinz W [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland)

    2009-12-31

    The review briefly considers the problems of synthesis and chemical identification of superheavy elements. The specific features of their properties are determined by the relativistic effects. The synthesis and chemical investigations into bohrium and element 112 are discussed as examples.

  16. Q-value effects in the synthesis of superheavy elements

    International Nuclear Information System (INIS)

    Graeger, Reimar

    2010-01-01

    Superheavy elements (Z>or similar 104) only exist due to nuclear shell effects, which stabilize them against spontaneous fission (SF). Theoretical calculations predict these shell stabilization effects to reach a maximum at the closures of the next spherical proton and neutron shells, which are anticipated in the region between Z=114 and Z=126 and at N=184. More recent calculations, that also consider deformed nuclear shapes extended this picture and predicted deformed shell closures at Z=108 and at N=162, creating a region of enhanced stability around 270 Hs, confirmed in recent Hs chemistry experiments by measuring the decay of 270 Hs for the first time. Recently, the formation of deformed doubly-magic 270 Hs in the 4n evaporation channel in the fusion reactions 248 Cm( 26 Mg,4n), 244 Pu( 30 Si,4n), 238 U( 36 S,4n), and 226 Ra( 48 Ca,4n) was studied theoretically using a two-parameter Smoluchowski equation. Simple entrance channel arguments make compound nucleus (CN) formation appear favorable for systems with larger mass asymmetry. However, due to a lower reaction Q value, the reactions 238 U( 36 S,4n) 270 Hs and 226 Ra( 48 Ca,4n) 270 Hs are predicted to have higher cross sections compared to the reactions 248 Cm( 26 Mg,4n) 270 Hs and 244 Pu( 30 Si,4n) 270 Hs. The aim of the research done in the framework of this thesis was to study the influence of the reaction (B-Q)-value on the yield of SHE produced in nuclear fusion reactions. Therefore the most promising reactions 36 S+ 238 U and 48 Ca+ 226 Ra have been investigated and compared with the already measured reaction 26 Mg+ 248 Cm. The reaction 36 S+ 238 U was investigated at two beam energies. One correlated decay chain attributed to 270 Hs was found at E * =51 MeV resulting in a cross section of 0.8 -0.7 +2.6 pb. The reaction 48 Ca+ 226 Ra was investigated at three beam energies. Six correlated decay chains attributed to 270 Hs were detected at E * =40 MeV corresponding to a cross section of 8.3 -3.7 +6.7 pb

  17. Review of even element super-heavy nuclei and search for element 120

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, S. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Goethe-Universitaet Frankfurt, Institut fuer Physik, Frankfurt (Germany); Heinz, S.; Mann, R.; Maurer, J.; Barth, W.; Burkhard, H.G.; Dahl, L.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Runke, J.; Scheidenberger, C.; Schoett, H.J.; Tinschert, K. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Muenzenberg, G. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Manipal University, Manipal Centre for Natural Sciences, Manipal, Karnataka (India); Antalic, S.; Saro, S. [Comenius University, Department of Nuclear Physics and Biophysics, Bratislava (Slovakia); Eberhardt, K.; Thoerle-Pospiech, P.; Trautmann, N. [Johannes Gutenberg-Universitaet Mainz, Mainz (Germany); Grzywacz, R. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Tennessee, Knoxville, TN (United States); Hamilton, J.H. [Vanderbuilt University, Department of Physics and Astronomy, Nashville, TN (United States); Henderson, R.A.; Kenneally, J.M.; Moody, K.J.; Shaughnessy, D.A.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Miernik, K. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Warsaw, Warsaw (Poland); Miller, D. [University of Tennessee, Knoxville, TN (United States); Morita, K. [RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama (Japan); Nishio, K. [Japan Atomic Energy Agency, Tokai, Ibaraki (Japan); Popeko, A.G.; Yeremin, A.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Roberto, J.B.; Rykaczewski, K.P. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Uusitalo, J. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland)

    2016-06-15

    The reaction {sup 54}Cr + {sup 248}Cm was investigated at the velocity filter SHIP at GSI, Darmstadt, with the intention to study production and decay properties of isotopes of element 120. Three correlated signals were measured, which occurred within a period of 279ms. The heights of the signals correspond with the expectations for a decay sequence starting with an isotope of element 120. However, a complete decay chain cannot be established, since a signal from the implantation of the evaporation residue cannot be identified unambiguously. Measured properties of the event chain are discussed in detail. The result is compared with theoretical predictions. Previously measured decay properties of even element super-heavy nuclei were compiled in order to find arguments for an assignment from the systematics of experimental data. In the course of this review, a few tentatively assigned data could be corrected. New interpretations are given for results which could not be assigned definitely in previous studies. The discussion revealed that the cross-section for production of element 120 could be high enough so that a successful experiment seems possible with presently available techniques. However, a continuation of the experiment at SHIP for a necessary confirmation of the results obtained in a relatively short irradiation of five weeks is not possible at GSI presently. Therefore, we decided to publish the results of the measurement and of the review as they exist now. In the summary and outlook section we also present concepts for the continuation of research in the field of super-heavy nuclei. (orig.)

  18. Synthesis of superheavy elements: Uncertainty analysis to improve the predictive power of reaction models

    OpenAIRE

    Lu , H.; Boilley , D.; Abe , Y.; Shen , C.

    2016-01-01

    13 pages, 13 figures, submitted for publication in PRC; International audience; Background: Synthesis of super-heavy elements is performed by heavy-ion fusion-evaporation reactions. However , fusion is known to be hindered with respect to what can be observed with lighter ions. Thus some delicate ambiguities remain on the fusion mechanism that eventually lead to severe discrepancies in the calculated formation probabilities coming from different fusion models. Purpose: In the present work, we...

  19. Barium isotopes in Allende meteorite - Evidence against an extinct superheavy element

    Science.gov (United States)

    Lewis, R. S.; Anders, E.; Shimamura, T.; Lugmair, G. W.

    1983-01-01

    Carbon and chromite fractions from the Allende meteorite that contain isotopically anomalous xenon-131 to xenon-136 (carbonaceous chondrite fission or CCF xenon) at up to 5 x 10 to the 11th atoms per gram show no detectable isotopic anomalies in barium-130 to barium-138. This rules out the possibility that the CCF xenon was formed by in situ fission of an extinct superheavy element. Apparently the CCF xenon and its carbonaceous carrier are relics from stellar nucleosynthesis.

  20. Nuclear spectroscopy with Geant4. The superheavy challenge

    Science.gov (United States)

    Sarmiento, Luis G.

    2016-12-01

    The simulation toolkit Geant4 was originally developed at CERN for high-energy physics. Over the years it has been established as a swiss army knife not only in particle physics but it has seen an accelerated expansion towards nuclear physics and more recently to medical imaging and γ- and ion- therapy to mention but a handful of new applications. The validity of Geant4 is vast and large across many particles, ions, materials, and physical processes with typically various different models to choose from. Unfortunately, atomic nuclei with atomic number Z > 100 are not properly supported. This is likely due to the rather novelty of the field, its comparably small user base, and scarce evaluated experimental data. To circumvent this situation different workarounds have been used over the years. In this work the simulation toolkit Geant4 will be introduced with its different components and the effort to bring the software to the heavy and superheavy region will be described.

  1. Theoretical Predictions of Cross-Sections of the Super-Heavy Elements

    Science.gov (United States)

    Bouriquet, B.; Kosenko, G.; Abe, Y.

    The evaluation of the residue cross-sections of reactionssynthesising superheavy elements has been achieved by the combination of the two-step model for fusion and the evaporation code (KEWPIE) for survival probability. The theoretical scheme of those calculations is presented, and some encouraging results are given, together with some difficulties. With this approach, the measured excitation functions of the 1n reactions producing elements with Z=108, 110, 111 and 112 are well reproduced. Thus, the model has been used to predict the cross-sections of the reactions leading to the formation of the elements with Z=113 and Z=114.

  2. Theoretical predictions of cross-sections of the super-heavy elements

    International Nuclear Information System (INIS)

    Bouriquet, B.; Abe, Y.; Kosenko, G.

    2004-01-01

    The evaluation of the residue cross-sections of reactions synthesising superheavy elements has been achieved by the combination of the two-step model for fusion and the evaporation code (KEWPIE) for survival probability. The theoretical scheme of those calculations is presented, and some encouraging results are given, together with some difficulties. With this approach, the measured excitation functions of the 1n reactions producing elements with Z = 108, 110, 111 and 112 are well reproduced. Thus, the model has been used to predict the cross-sections of the reactions leading to the formation of the elements with Z = 113 and Z = 114. (author)

  3. What can we learn from the fission time of the super-heavy elements?

    OpenAIRE

    Boilley, D.; Marchix, A.; Wilgenbus, D.; Lallouet, Y.; Gimbert, F.; Abe, Y.

    2007-01-01

    International audience; Recent experiments performed at GANIL with a crystal blocking technique have shown direct evidences of long fission times in the Super-Heavy Elements (SHE) region. Aimed to localize the SHE island of stability, can these experiments give access to the fission barrier and then to the shell-correction energy? In this paper, we calculate the fission time of heavy elements by using a new code, KEWPIE2, devoted to the study of the SHE.We also investigate the effect of poten...

  4. Status of the low-energy super-heavy element facility at RIKEN

    Energy Technology Data Exchange (ETDEWEB)

    Schury, P., E-mail: schury@riken.jp [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Wada, M.; Ito, Y. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Arai, F. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Institute of Physics, University of Tsukuba, Tsukuba City, Ibaraki (Japan); Kaji, D. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Kimura, S. [Institute of Physics, University of Tsukuba, Tsukuba City, Ibaraki (Japan); Morimoto, K.; Haba, H. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Jeong, S. [Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Koura, H. [Advanced Science Research Center, Japan Atomic Energy Agency, Ibaraki 319-1195 (Japan); Miyatake, H. [Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Morita, K.; Reponen, M. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Ozawa, A. [Institute of Physics, University of Tsukuba, Tsukuba City, Ibaraki (Japan); Sonoda, T.; Takamine, A. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Wollnik, H. [Dept. Chemistry and BioChemistry, New Mexico State University, Las Cruces, NM (United States)

    2016-06-01

    In order to investigate nuclei produced via fusion–evaporation reactions, especially super-heavy elements (SHE), we have begun construction of a facility for conversion of fusion–evaporation residues (EVR) to low-energy beams. At the base of this facility is a small cryogenic gas cell utilizing a traveling wave RF-carpet, located directly following the gas-filled recoil ion separator GARIS-II, which will thermalize EVRs to convert them into ion beams amenable to ion trapping. We present here the results of initial studies of this small gas cell.

  5. Superheavy-element fission tracks in iron meteorites, and reply by Bull, R.K

    International Nuclear Information System (INIS)

    Runcorn, S.K.

    1980-01-01

    Comment is made on the lack of superheavy element (SHE) fission tracks observed in silicates from the class IA Odessa iron meteorite by Bull (Nature; 282:393 (1979)). Two explanations are suggested. Firstly, a thermal history for Odessa can be constructed in which the meteorite reaches track retention temperatures only after a time corresponding to many half lives for the SHEs (taken to be approximately 100 Myr) has elapsed and secondly that the IA irons never took up many SHEs. These suggestions are discussed in a reply by Bull. (U.K.)

  6. The synthesis of the deformed superheavy elements 107 to 111

    International Nuclear Information System (INIS)

    Armbuster, P.

    1995-01-01

    By inflight separation, implantation into Si-detector arrays, and correlation analysis of subsequent α-decay chains many isotopes were discovered at GSI since 1980, among others the elements Nielsbohriurn, Hassium and Meitnerium. The sensitivity of the method allows to identify an element by one decay chain, as we demonstrated for the case of 266 Mt. After a break of our work during the time when the new accelerator system SIS-FRS-ESR was installed (1989-1993) at GSI, and many improvements of our system EZR-UNILAC-SHIP accomplished, we restarted element synthesis in 1994. The synthesis of the isotopes 269 110, 271 110, and 272 111 of the new elements Z--110 and Z=l11 was a first success at the end of 1994. This discovery is in the center of this presentation. The reaction mechanism, a one-step, cold and compact rearrangement process at a level of some 10 -36 cm 2 is discussed. Cross sections and excitation functions systematically studied allow to extrapolate to the next element Z=112, which seems not to be out of reach

  7. Frontiers of heavy-ion physics and superheavy elements

    International Nuclear Information System (INIS)

    Muenzenberg, Gottfried

    2002-01-01

    This contribution will focus on three topics of GSI nuclear structure research: super heavy elements, direct mass measurements in the storage ring, and the measurement of spallation cross section in reversed kinematics. The GSI project for an extended synchrotron facility will be outlined. (author)

  8. Search for superheavy elements in the reaction 238U+9.6 MeV/N 63Cu,65Cu

    International Nuclear Information System (INIS)

    Esterlund, R.A.; Molzahn, D.; Brandt, R.; Patzelt, P.; Vater, P.; Boos, A.H.

    1976-01-01

    According to calculations of NIX and others, the formation of superheavy elements might occur in heavy-ion reaction systems such as the one under investigation in the present work i.e., 238 U + 63 Cu and 65 Cu at 9.6 MeV/nucleon. Since previous experiments have indicated that upper limits to the production cross-section for superheavy elements are extremely low, two rather long irradiations of 27 hrs and 42 hrs, respectively, have been carried out at the University of Manchester LINAC. The first run has already been reported on in the literature. In the case of the second run, after chemical separation into HgS, CdS, and La(OH) 3 fractions, the samples were assayed simultaneously and continuously over a period of 6 months for alpha- and spontaneous-fission activity, using Si surface-barrier detector. Each sample was at the same time mounted on mica, for the purpose of scanning for fission tracks at a later date. No indications from the data have so far been found that superheavy elements were produced. Possible reasons for the failure to detect superheavy elements in this experiment are: The half-life of any product is either too short (a few hours) or too long (a few years); the chemical properties of the superheavy elements are very different from those predicted; the position of the superheavy island is not where it is commonly assumed to be and may, for example, be at Z>=114 and N>=184, as predicted by ROUBEN et al. (T.G.)

  9. Validation of new superheavy elements and IUPAC-IUPAP joint working group

    International Nuclear Information System (INIS)

    Jarlskog, Cecilia

    2016-01-01

    The great chemist Glenn Seaborg has written a delightful little book “Man-made Transuranium Elements”, published in 1963, in which he points out that: “The former basic criterion for the discovery of a new element – namely, chemical identification and separation from all previously-known elements – had to be changed in the case of lawrencium (element 103). This also may be true for elements beyond lawrencium.” Indeed this is what has happened. The elements with Z ≥ 103 are produced in nuclear reactions and are detected by counters. The detectors have undergone substantial refinement. For example one uses multiwire proportional chambers [for which George Charpak received the 1992 Nobel Prize in Physics] as well as solid state micro-strip detectors. In spite of this remarkable shift from chemistry to physics, the managerial staff of the International Union of Pure and Applied Chemistry (IUPAC) does not seem to be aware of what has been going on. The validation of superheavy elements should be done by physicists as the chemists lack the relevant competence as I will discuss here below. This article is about a collaboration between International Union of Pure and Applied Chemistry (IUPAC) and its sister organization International Union of Pure and Applied Physics (IUPAP), to deal with discovery of superheavy elements beyond Z = 112. I spent a great deal of time on this issue. In my opinion, the collaboration turned out to be a failure. For the sake of science, which should be our most important concern (and not politics), the rules for the future collaborations, if any, should be accurately defined and respected. The validation of new elements should be done by people who have the relevant competence – the physicists.

  10. Nuclear structure studies towards superheavy elements and perspectives with AGATA

    International Nuclear Information System (INIS)

    Korichi, A.

    2005-01-01

    A variety of theoretical approaches have been used to calculate the shell closure of spherical Super Heavy Elements (SHE) but the predictions of the location of the 'island of stability' vary from Z=114 to 120 and 126, with neutron numbers around N=172 or N=184 depending on the model employed. A deformed minimum around Z=108 and N=162 is predicted and an increase of the half-life of Hassium (Z=108) is experimentally observed when approaching the neutron number N=162. Super heavy nuclei are produced with very low cross-section (a few picobarns) and this makes their spectroscopic study impossible with today's beam intensities and detectors. However, important information can be obtained from the structure of mid-shell deformed nuclei (Z∼104) where selected single particle orbitals, which lie close to the spherical shell gap in SHE, are close to the Fermi level. The information will come from decay and in-beam spectroscopy. A promising area of progress, using the state-of-the art instruments, is represented by the observation of rotational gamma-ray transitions in No and Fm isotopes showing the deformed character of these nuclei. One of the objectives and focus of the nuclear structure community is related to the investigation of Single particle excitations beyond the N=152 neutron gap and collective properties of heavier systems towards Z∼104. The IN2P3-JINR collaboration has launched a project of electron and gamma-ray spectroscopy studies of heavy nuclei at the FLNR. This project benefits from the radioactive actinide targets uniquely available at Dubna and from the very intense stable beams provided by the U400 cyclotron. This offers a unique opportunity for the study of nuclei above Z=100 along an isotopic chain approaching N=162. In this contribution, the emphasis will be on the GABRIELA project and its issues. I will finally point out the perspectives with the new generation of gamma detectors such as AGATA

  11. A novel approach to the island of stability of super-heavy elements search

    Directory of Open Access Journals (Sweden)

    Wieloch A.

    2016-01-01

    Full Text Available It is expected that the cross section for super-heavy nuclei production of Z > 118 is dropping into the region of tens of femto barns. This creates a serious limitation for the complete fusion technique that is used so far. Moreover, the available combinations of the neutron to proton ratio of stable projectiles and targets are quite limited and it can be difficult to reach the island of stability of super heavy elements using complete fusion reactions with stable projectiles. In this context, a new experimental investigation of mechanisms other than complete fusion of heavy nuclei and a novel experimental technique are invented for our search of super- and hyper-nuclei. This contribution is focused on that technique.

  12. New approach to description of fusion-fission dynamics in super-heavy element formation

    International Nuclear Information System (INIS)

    Zagrebaev, V.I.

    2002-01-01

    A new mechanism of the fusion-fission process for a heavy nuclear system is proposed, which takes place in the (A 1 , A 2 ) space, where A 1 and A 2 are two nuclei, surrounded by a certain number of shared nucleons ΔA. The nuclei A 1 and A 2 gradually lose (or acquire) their individualities with increasing (or decreasing) a number of collectivized nucleons ΔA. The driving potential in the (A 1 , A 2 ) space is derived, which allows the calculation of both the probability of the compound nucleus formation and the mass distribution of fission and quasi-fission fragments in heavy ion fusion reactions. The cross sections of super-heavy element formation in the 'hot' and 'cold' fusion reactions have been calculated up to Z CN =118. (author)

  13. First prompt in-beam γ-ray spectroscopy of a superheavy element: the 256Rf

    International Nuclear Information System (INIS)

    Rubert, J; Dorvaux, O; Gall, B J P; Asfari, Z; Piot, J; Greenlees, P T; Grahn, T; Herzan, A; Jakobsson, U; Jones, P; Julin, R; Juutinen, S; Andersson, L L; Cox, D M; Herzberg, R-D; Asai, M; Dechery, F; Hauschild, K; Henning, G; Heßberger, F P

    2013-01-01

    Using state-of-the-art γ-ray spectroscopic techniques, the first rotational band of a superheavy element, extending up to a spin of 20 h, was discovered in the nucleus 256 Rf. To perform such an experiment at the limits of the present instrumentation, several developments were needed. The most important of these developments was of an intense isotopically enriched 50 Ti beam using the MIVOC method. The experimental set-up and subsequent analysis allowed the 256 Rf ground-state band to be revealed. The rotational properties of the band are discussed and compared with neighboring transfermium nuclei through the study of their moments of inertia. These data suggest that there is no evidence of a significant deformed shell gap at Z = 104.

  14. From transuranic to superheavy elements a story of dispute and creation

    CERN Document Server

    Kragh, Helge

    2018-01-01

    The story of superheavy elements  - those at the very end of the periodic table  - is not well known outside the community of heavy-ion physicists and nuclear chemists. But it is a most interesting story which deserves to be known also to historians, philosophers, and sociologists of science and indeed to the general public. This is what the present work aims at. It tells the story or rather parts of the story, of how physicists and chemists created elements heavier than uranium or searched for them in nature. And it does so with an emphasis on the frequent discovery and naming disputes concerning the synthesis of very heavy elements. Moreover, it calls attention to the criteria which scientists have adopted for what it means to have discovered a new element. In this branch of modern science it may be more appropriate to speak of creation instead of discovery. The work will be of interest to scientists as well as to scholars studying modern science from a meta-perspective.

  15. Exploration of (super-)heavy elements using the Skyrme-Hartree-Fock model

    International Nuclear Information System (INIS)

    Erler, Jochen

    2011-01-01

    Motivated by the steadily increasing number of known nuclei and nuclear properties, theories of nuclear structure are presently a field of intense research. This work concentrates on the self-consistent description of nuclei in terms of the Skyrme-Hartree-Fock (SHF) approach. The extrapolation of nuclear shell structure to the region of super-heavy elements (SHE) using the SHF model, the dependence on different parameterization and the influence of collective correlation will be studied. The general scope of this work are large scale calculation for a global survey of properties of SHE like binding energies, separation energies and decay characteristics and lifetimes. These calculations were done in a collaboration with the theory group of the GSI in Darmstadt and have the aim to develop a database of lifetimes and reaction rates for α, β-decay and spontaneous fission in a very wide range with proton numbers 86 ≤ Z ≤ 120 and neutron numbers up to N ∼ 260 relevant for the astrophysical r-process. The results of this study for example predictions of a possible islands of very stable nuclei and information of favored decay mode for each nuclei are also applicable in the recent experimental synthesis of exotic SHE. For these calculation a framework to calculate β-decay half-lives within the SHF model has been developed and the existing axial SHF code has been extended to compute β-transition matrix elements and so to provide an estimation of half-lives. (orig.)

  16. Exploration of (super-)heavy elements using the Skyrme-Hartree-Fock model

    Energy Technology Data Exchange (ETDEWEB)

    Erler, Jochen

    2011-01-31

    Motivated by the steadily increasing number of known nuclei and nuclear properties, theories of nuclear structure are presently a field of intense research. This work concentrates on the self-consistent description of nuclei in terms of the Skyrme-Hartree-Fock (SHF) approach. The extrapolation of nuclear shell structure to the region of super-heavy elements (SHE) using the SHF model, the dependence on different parameterization and the influence of collective correlation will be studied. The general scope of this work are large scale calculation for a global survey of properties of SHE like binding energies, separation energies and decay characteristics and lifetimes. These calculations were done in a collaboration with the theory group of the GSI in Darmstadt and have the aim to develop a database of lifetimes and reaction rates for {alpha}, {beta}-decay and spontaneous fission in a very wide range with proton numbers 86 {<=} Z {<=} 120 and neutron numbers up to N {approx} 260 relevant for the astrophysical r-process. The results of this study for example predictions of a possible islands of very stable nuclei and information of favored decay mode for each nuclei are also applicable in the recent experimental synthesis of exotic SHE. For these calculation a framework to calculate {beta}-decay half-lives within the SHF model has been developed and the existing axial SHF code has been extended to compute {beta}-transition matrix elements and so to provide an estimation of half-lives. (orig.)

  17. Coprecipitation experiment with Sm hydroxide using a multitracer produced by nuclear spallation reaction: A tool for chemical studies with superheavy elements

    International Nuclear Information System (INIS)

    Kasamatsu, Yoshitaka; Yokokita, Takuya; Toyomura, Keigo; Shigekawa, Yudai; Haba, Hiromitsu; Kanaya, Jumpei; Huang, Minghui; Ezaki, Yutaka; Yoshimura, Takashi; Morita, Kosuke; Shinohara, Atsushi

    2016-01-01

    To establish a new methodology for superheavy element chemistry, the coprecipitation behaviors of 34 elements with samarium hydroxide were investigated using multitracer produced by a spallation of Ta. The chemical reactions were rapidly equilibrated within 10 s for many elements. In addition, these elements exhibited individual coprecipitation behaviors, and the behaviors were qualitatively related to their hydroxide precipitation behaviors. It was demonstrated that the ammine and hydroxide complex formations of superheavy elements could be investigated using the established method. - Highlights: • We established a new methodology for superheavy element (SHE) chemistry. • Coprecipitation behaviors of 34 elements with Sm hydroxide could be simultaneously investigated by using multitracer. • The complex formations were investigated from the coprecipitation behaviors. • The established method will lead to the study on various precipitates of SHEs.

  18. Hydration energies and specific influence of oxo complexes and high coordination numbers on the predicted chemistry of superheavy elements

    International Nuclear Information System (INIS)

    Jorgensen, C.K.; Penneman, R.A.

    1975-01-01

    On the basis of an analysis of the known ionization energies of gaseous ions and aqua ions of the 3d, 4f, and 6d transition groups and the radius effects, the chemistry of the superheavy elements is predicted. The formation of aqua ion and oxo complexes in the elements with Z below 121 is considered. It is probable that the series from 123 to 140 constitute a close analogy to the lanthanides with Th-like chemistry. Above Z = 140 the elements will probably displace a transition group behavior. A brief comment is made on the analytical aspects to be expected. (U.S.)

  19. Measurements of Plutonium isotopes and the search for super-heavy elements via AMS

    International Nuclear Information System (INIS)

    Wallner, A.; Steier, P.; Golser, R.; Knie, K.; Kutschera, W.; Priller, A.; Hrnecek, E.; Jakopic, R.; Korschinek, G.

    2006-01-01

    Full text: Accelerator Mass Spectrometry (AMS) - being independent on the half-life of a radionuclide - provides a technique to determine isotope ratios with the highest sensitivity and allows the measurement of radionuclides over a wide dynamic range of concentration levels. A combination of AMS, Alpha Spectrometry and Liquid Scintillation Counting was used for the determination of the complete information on isotope ratios of Plutonium isotopes in different environmental reference samples (e.g. from the atolls of Mururoa and Fangataufa) and samples contaminated from nuclear reprocessing. Results for the isotopic ratios of the samples will be shown and the capabilities and detection limits achievable for determination of Pu will be discussed. The long-lived 244 Pu (t 1/2 = 80 Ma) and 247 Cm (t 1/2 = 15.6 Ma) have a very interesting application in astrophysics by detecting possible supernova-produced 244 Pu and 247 Cm in terrestrial archives. The expected extremely small concentrations of 244 Pu makes AMS the favorite method. The actual search for such long-lived extraterrestrial radionuclides and possible implications will be presented. The same method has also been explored for a pinprick-search of long-lived super-heavy elements in the mass region above Z=100. (author)

  20. The cross sections of fusion-evaporation reactions: the most promising route to superheavy elements beyond Z=118

    Directory of Open Access Journals (Sweden)

    Jadambaa Khuyagbaatar

    2017-01-01

    Full Text Available The synthesis of superheavy elements beyond oganesson (Og, which has atomic number Z = 118, is currently one of the main topics in nuclear physics. An absence of sufficient amounts of target material with atomic numbers heavier than californium (Z = 98 forces the use of projectiles heavier than 48Ca (Z = 20, which has been successfully used for the discoveries of elements with Z = 114 - 118 in complete fusion reactions. Experimental cross sections of 48Ca with actinide targets behave very differently to “cold” and “hot” fusion-evaporation reactions, where doubly-magic lead and deformed actinides are used as targets, respectively. The known cross sections of these reactions have been analysed compared to calculated fission barriers. It has been suggested that observed discrepancies between the cross sections of 48Ca-induced and other fusionevaporation reactions originate from the shell structure of the compound nucleus, which lies in the island of the stability. Besides scarcely known data on other reactions involving heavier projectiles, the most promising projectile for the synthesis of the elements beyond Og seems to be 50Ti. However, detailed studies of 50Ti, 54Cr, 58Fe and 64Ni-induced reactions are necessary to be performed in order to fully understand the complexities of superheavy element formation.

  1. The cross sections of fusion-evaporation reactions: the most promising route to superheavy elements beyond Z=118

    Science.gov (United States)

    Jadambaa, Khuyagbaatar

    2017-11-01

    The synthesis of superheavy elements beyond oganesson (Og), which has atomic number Z = 118, is currently one of the main topics in nuclear physics. An absence of sufficient amounts of target material with atomic numbers heavier than californium (Z = 98) forces the use of projectiles heavier than 48Ca (Z = 20), which has been successfully used for the discoveries of elements with Z = 114 - 118 in complete fusion reactions. Experimental cross sections of 48Ca with actinide targets behave very differently to "cold" and "hot" fusion-evaporation reactions, where doubly-magic lead and deformed actinides are used as targets, respectively. The known cross sections of these reactions have been analysed compared to calculated fission barriers. It has been suggested that observed discrepancies between the cross sections of 48Ca-induced and other fusionevaporation reactions originate from the shell structure of the compound nucleus, which lies in the island of the stability. Besides scarcely known data on other reactions involving heavier projectiles, the most promising projectile for the synthesis of the elements beyond Og seems to be 50Ti. However, detailed studies of 50Ti, 54Cr, 58Fe and 64Ni-induced reactions are necessary to be performed in order to fully understand the complexities of superheavy element formation.

  2. Structure of exotic nuclei and superheavy elements in meson field theory

    International Nuclear Information System (INIS)

    Linn, Khin Nyan

    2008-07-01

    In this work the nuclear structure of exotic nuclei and superheavy nuclei is studied in a relativistic framework. In the relativistic mean-field (RMF) approximation, the nucleons interact with each other through the exchange of various effective mesons (scalar, vector, isovector-vector). Ground state properties of exotic nuclei and superheavy nuclei are studied in the RMF theory with the three different parameter sets (ChiM,NL3,NL-Z2). Axial deformation of nuclei within two drip lines are performed with the parameter set (ChiM). The position of drip lines are investigated with three different parameter sets (ChiM,NL3,NL-Z2) and compared with the experimental drip line nuclei. In addition, the structure of hypernuclei are studied and for a certain isotope, hyperon halo nucleus is predicted. (orig.)

  3. Structure of exotic nuclei and superheavy elements in meson field theory

    Energy Technology Data Exchange (ETDEWEB)

    Linn, Khin Nyan

    2008-07-15

    In this work the nuclear structure of exotic nuclei and superheavy nuclei is studied in a relativistic framework. In the relativistic mean-field (RMF) approximation, the nucleons interact with each other through the exchange of various effective mesons (scalar, vector, isovector-vector). Ground state properties of exotic nuclei and superheavy nuclei are studied in the RMF theory with the three different parameter sets (ChiM,NL3,NL-Z2). Axial deformation of nuclei within two drip lines are performed with the parameter set (ChiM). The position of drip lines are investigated with three different parameter sets (ChiM,NL3,NL-Z2) and compared with the experimental drip line nuclei. In addition, the structure of hypernuclei are studied and for a certain isotope, hyperon halo nucleus is predicted. (orig.)

  4. Relativistic pseudopotential model for superheavy elements: applications to chemistry of eka-Hg and eka-Pb

    Energy Technology Data Exchange (ETDEWEB)

    Zaitsevskii, Andrei V [Institute of Hydrogen Energetics and Plasma Technologies, Russian Research Centre ' Kurchatov Institute' (Russian Federation); Wuellen, C van [Technische Universitaet Kaiserslautern (Germany); Titov, A V [B P Konstantinov Petersburg Nuclear Physics Institute, Russian Academy of Sciences (Russian Federation)

    2009-12-31

    Relativistic pseudopotential approach to the electronic structure simulation of superheavy elements (SHE) compounds is presented. Advanced formulations of this approach leaving both valence and outer-core electronic shells for explicit treatment give rise to simple and efficient computational techniques ensuring highly accurate description of most chemical properties of SHE. At present, the errors due to the use of approximate methods for solving the correlation problem for a subsystem of valence electrons are much larger than those stemming from the pseudopotential approximation itself. Recent applications to the studies of the chemistry of elements 112 (eka-Hg) and 114 (eka-Pb) are reviewed; properties of these elements and their lighter homologues, Hg and Pb, are compared.

  5. State of art in experimental studies and theory of superheavy elements

    International Nuclear Information System (INIS)

    Zvara, I.

    2002-01-01

    Recent years have seen remarkable progress in synthesizing new, superheavy' elements (SHE). Researchers at Dubna reached the slopes of the expected 'island of stability' (around Z = 114 and N = 184) in a 'sea' of nuclides with very short partial half-lives against spontaneous fission and/or alpha decay. In long bombardments (weeks to months) of isotopes of U, Pu and Cm by very intense (3x10 12 s -1 ) beams of 48 Ca projectiles, they have discovered mostly alpha active isotopes of previously unknown elements 116 and 114, as well as of element 112, all with unusually long half-lives - up to minutes. Only physical methods have been used for isolation and identification of the produced new nuclei. These findings give an impetus to chemical studies. Feasibility of experiments critically depends on half-lives and production cross section. Lifetimes of the order of a second or more are necessary for some gas phase chemistry studies, but at least some 10 seconds for solution chemistry. The production rates of observable atoms might be higher in chemical studies, because chemists can make use of thicker targets, and achieve higher (chemical) yield and detection efficiency than in physical experiments. Work on chemical identification of the 3-min 283 112 is in progress at Dubna and planned in other laboratories. Being a homologue of Hg, element 112 must be even more volatile metal. Thanks to this, hopefully, its single atoms, will be easily separated from interfering activities simultaneously produced in the bombardment. Quantum (theoretical) chemistry studies aim at solving the problem of 'relativistic effects' in chemical properties of SHE; such effects increase with higher Z's. As the available calculational resources fast and steadily grow (unlike the beam time available at accelerators) one can hope that quantum chemists will once be able to advise the experimenters which kind of studies to do to obtain most important and interesting results. This is not yet possible

  6. Isomeric States in the Second and Third Well of the Potential and Long-Lived Superheavy Element

    International Nuclear Information System (INIS)

    Marinov, A.; Gelberg, S.; Kolb, D.

    1999-01-01

    Recently, in a study of the 16 O + 197 Au and 28 Si + 181 Ta reactions near and below the Coulomb barrier, long-lived high spin isomeric states have been found by us in the second and third well of the potential-energy surfaces. Such isomeric states have very unusual physical properties. In addition to their very long lifetimes, much longer than of their corresponding ground states, they have very unusual decay properties. They may decay by 5 to 7 orders of magnitude enhanced alpha particles, in transitions from the second or third well of the potential in the parent nuclei to the respective well in the daughters, or by very retarded alpha particles, in transitions from the second well in the parent nucleus to normal states in the daughter, or from the third well in the parent to the second well in the daughter. They also may decay by long-lived proton activities, in transitions from the second well in the parent nucleus to the normal states in the daughter. Experimental evidences for all these new phenomena will be presented in the conference. The existence of long-lived isomeric states in the second and third well of the potential is very important when the production of superheavy elements is considered. Because of the very much reduced extra-push energy needed for their production, they may be produced much easier than the normal states, in reactions between very heavy nuclei. In particular, the discovery of the long-lived superheavy element with Z = 112 can consistently be understood

  7. Gas phase chemical studies of superheavy elements using the Dubna gas-filled recoil separator - Stopping range determination

    International Nuclear Information System (INIS)

    Wittwer, D.; Abdullin, F.Sh.; Aksenov, N.V.; Albin, Yu.V.; Bozhikov, G.A.; Dmitriev, S.N.; Dressler, R.; Eichler, R.; Gaeggeler, H.W.; Henderson, R.A.; Huebener, S.; Kenneally, J.M.; Lebedev, V.Ya.; Lobanov, Yu.V.; Moody, K.J.; Oganessian, Yu.Ts.; Petrushkin, O.V.; Polyakov, A.N.; Piguet, D.; Rasmussen, P.

    2010-01-01

    Currently, gas phase chemistry experiments with heaviest elements are usually performed with the gas-jet technique with the disadvantage that all reaction products are collected in a gas-filled thermalisation chamber adjacent to the target. The incorporation of a physical preseparation device between target and collection chamber opens up the perspective to perform new chemical studies. But this approach requires detailed knowledge of the stopping force (STF) of the heaviest elements in various materials. Measurements of the energy loss of mercury (Hg), radon (Rn), and nobelium (No) in Mylar and argon (Ar) were performed at low kinetic energies of around (40-270) keV per nucleon. The experimentally obtained values were compared with STF calculations of the commonly used program for calculating stopping and ranges of ions in matter (SRIM). Using the obtained data points an extrapolation of the STF up to element 114, eka-lead, in the same stopping media was carried out. These estimations were applied to design and to perform a first chemical experiment with a superheavy element behind a physical preseparator using the nuclear fusion reaction 244 Pu( 48 Ca; 3n) 289 114. One decay chain assigned to an atom of 285 112, the α-decay product of 289 114, was observed.

  8. Are there superheavy atomic nuclei

    International Nuclear Information System (INIS)

    Herrmann, G.

    1982-04-01

    The author presents a populary introduction to the formation of nuclei with special regards to superheavy nuclei. After a general description of the methods of physics the atomic hypothesis is considered. Thereafter the structure of the nucleus is discussed, and the different isotopes are considered. Then radioactivity is described as an element transmutation. Thereafter the thermonuclear reactions in the sun are considered. Then the synthesis of elements using heavy ion reactions is described. In this connection the transuranium elements and the superheavy elements are considered. (orig./HSI) [de

  9. Search for long-lived superheavy elements in the reaction system 238U + 9.6-MeV/nucleon 63/sub,/65Cu

    International Nuclear Information System (INIS)

    Esterlund, R.A.; Molzahn, D.; Brandt, R.; Patzelt, P.; Vater, P.; Boos, A.H.; Chandratillake, M.R.; Grant, I.S.; Hemingway, J.D.; Newton, G.W.A.

    1977-01-01

    A thick 238 U target has been bombarded with 63 /sub,/ 65 Cu ions at an incident beam energy of 9.6 MeV/nucleon. After radiochemical separations into CdS, HgS, and La-oxalate fractions, a search for evidence of the production of superheavy elements was undertaken using Si surface-barrier detectors and mica foils simultaneously for detection of spontaneous-fission events and high-energy α emission. No evidence for the presence of superheavy elements in the samples was found. Upper limits for production cross sections for superheavy elements in each of the three chemical samples, assuming an arbitrary half-life of 100 days and a target thickness equal to the entire reaction range of the incident ions from initial energy to the reaction barrier, are as follows: (a) CdS (Z = 108--115): 1 x 10 -34 cm 2 ; (b) HgS (Z = 112): 6 x 10 -35 cm 2 ; (c) La-oxalate ( 254 Cf): 8 x 10 -35 cm 2

  10. Studies on the synthesis of isotopes of superheavy element Lv (Z = 116)

    Energy Technology Data Exchange (ETDEWEB)

    Santhosh, K.P.; Safoora, V. [Kannur University, School of Pure and Applied Physics, Payyanur (India)

    2017-11-15

    The probable projectile-target combinations for the synthesis of superheavy nucleus {sup 296}Lv found in the cold valley of {sup 296}Lv have been identified by studying the interaction barrier of the colliding nuclei, probability of compound nucleus formation, P{sub CN}, and survival probability W{sub sur}. At energies near and above the Coulomb barrier, the capture, fusion and evaporation residue (ER) cross sections for the probable combinations for the hot and cold fusion reactions are systematically investigated. By considering intensities of the projectile beams, availabilities of the targets and half lives of the colliding nuclei, the combination {sup 48}Ca + {sup 248}Cm is found to be the most probable projectile-target pair for the synthesis of {sup 296}Lv. The calculated maximum value of 2n, 3n, 4n and 5n channel cross section for the reaction {sup 48}Ca + {sup 248}Cm are 0.599 pb, 5.957 pb, 4.805 pb, and 0.065 pb, respectively. Moreover, the production cross sections for the synthesis of isotopes {sup 291-295,298}Lv using {sup 48}Ca projectile on {sup 243-247,250}Cm targets are calculated. Among these reactions, the reactions {sup 48}Ca + {sup 247}Cm → {sup 295}Lv and {sup 48}Ca + {sup 250}Cm → {sup 298}Lv have maximum production cross section in 3n (10.697 pb) and 4n (12.006 pb) channel, respectively. Our studies on the SHE Lv using the combinations {sup 48}Ca + {sup 245}Cm → {sup 293}Lv and {sup 48}Ca + {sup 248}Cm → {sup 296}Lv are compared with available experimental data and with other theoretical studies. Our studies are in agreement with experimental data and we hope that these studies will be a guide for the future experiments to synthesize the isotopes of Lv. (orig.)

  11. Model Experiments on Chemical Properties of Superheavy Elements in Aqueous Solutions

    CERN Document Server

    Szeglowski, Z

    2003-01-01

    This paper presents a brief review of model experiments on investigation of chemical properties of transactinide elements, ranging from 104 to 116. The possibilities of isolation of the nuclei of these elements from nuclear reaction products, using the ion-exchange method, are also considered.

  12. On the Source of the Systematic Errors in the Quatum Mechanical Calculation of the Superheavy Elements

    Directory of Open Access Journals (Sweden)

    Khazan A.

    2010-10-01

    Full Text Available It is shown that only the hyperbolic law of the Periodic Table of Elements allows the exact calculation for the atomic masses. The reference data of Periods 8 and 9 manifest a systematic error in the computer software applied to such a calculation (this systematic error increases with the number of the elements in the Table.

  13. On the Source of the Systematic Errors in the Quantum Mechanical Calculation of the Superheavy Elements

    Directory of Open Access Journals (Sweden)

    Khazan A.

    2010-10-01

    Full Text Available It is shown that only the hyperbolic law of the Periodic Table of Elements allows the exact calculation for the atomic masses. The reference data of Periods 8 and 9 manifest a systematic error in the computer software applied to such a calculation (this systematic error increases with the number of the elements in the Table.

  14. Toward an accurate description of solid-state properties of superheavy elements

    Directory of Open Access Journals (Sweden)

    Schwerdtfeger Peter

    2016-01-01

    Full Text Available In the last two decades cold and hot fusion experiments lead to the production of new elements for the Periodic Table up to nuclear charge 118. Recent developments in relativistic quantum theory have made it possible to obtain accurate electronic properties for the trans-actinide elements with the aim to predict their potential chemical and physical behaviour. Here we report on first results of solid-state calculations for Og (element 118 to support future atom-at-a-time gas-phase adsorption experiments on surfaces such as gold or quartz.

  15. New isotopes of elements 104, 106 and 108 - highly stable superheavy nuclei

    International Nuclear Information System (INIS)

    Oganessian, Yuri

    1994-01-01

    In April 1993, as part of a joint Dubna-Livermore experiment at the Flerov Laboratory of Nuclear Reactions, new heavy isotopes of elements 104 and 106 were synthesized - 262 104, 265 106 and 266 106. Compared with the known even-even isotopes of elements 104 and 106, the new nuclei are characterized by their extraordinary high resistance to spontaneous fission. This is a direct proof of the macro-microscopic theory predictions in its version calculated by A.Sobiczewski et al. regarding a substantial increase in the half-lives of heavy nuclei near deformed shells with atomic number (Z) 108 and neutron number (N) 162.

  16. Heavy-Ion Fusion Mechanism and Predictions of Super-Heavy Elements Production

    International Nuclear Information System (INIS)

    Abe, Yasuhisa; Shen Caiwan; Boilley, David; Giraud, Bertrand G.; Kosenko, Grigory

    2009-01-01

    Fusion process is shown to firstly form largely deformed mono-nucleus and then to undergo diffusion in two-dimensions with the radial and mass-asymmetry degrees of freedom. Examples of prediction of residue cross sections are given for the elements with Z = 117 and 118.

  17. Workshop of Advanced Science Research Center, JAERI. Nuclear physics and nuclear chemistry of superheavy elements

    International Nuclear Information System (INIS)

    Nishio, Katsuhisa; Nishinaka, Ichiro; Ikezoe, Hiroshi; Nagame, Yuichiro

    2004-03-01

    A liquid drop model predicts that the fission barrier of a nucleus whose atomic number (Z) is larger than 106 disappears, so that such heavier nuclei as Z > 106 cannot exist. The shell effect, however, drastically changes structure of the fission barrier and stabilizes nucleus against fission, predicting the presence of super heavy element (SHE, Z=114-126) with measurable half-life. In the SHE region, a wave function of outermost electron of an atom, which controls chemical properties of an elements, is disturbed or changed by relativistic effects compared to the one from the non-relativistic model. This suggests that the SHEs have different chemical properties from those of lighter elements belonging to the same family. The chemistry of SHEs requires event by event analysis to reveal their chemical properties, thus is called 'atom-at-a-time chemistry'. Japan Atomic Energy Research Institute (JAERI) has been investigating fusion mechanism between heavy nuclei to find out favorable reactions to produce SHE by using JAERI-tandem and booster accelerator. In the JAERI-tandem facility, isotopes of Rf and Db are produced by using actinide targets such as 248 Cm in order to investigate their chemical properties. The present workshop was held in Advanced Science Research Center of JAERI at February 27-28 (2003) in order to discuss current status and future plans for the heavy element research. The workshop also included topics of the radioactive nuclear beam project forwarded by the JAERI-KEK cooperation and the nuclear transmutation facility of J-PARC. Also included is the nuclear fission process as a decay characteristic of heavy elements. There were sixty participants in the workshop including graduate and undergraduate eleven students. We had guests from Germany and Hungary. Through the workshop, we had a common knowledge that researches on SHE in Japan should fill an important role in the world. (author)

  18. Synthesis of superheavy elements and dinuclear-system concept of compound-nucleus formation

    Energy Technology Data Exchange (ETDEWEB)

    Antonenko, N.V.; Adamian, G.G.; Cherepanov, E.A. [Joint Institute for Nuclear Research, Dubna (Russian Federation)] [and others

    1996-12-31

    Dinuclear system concept is applied to the analysis of reactions used for the synthesis of elements with Z = 110, 112, 114, and 116. The inner fusion barriers obtained for these reactions are in good agreement with the experimental estimations resulted from the excitation energies of compound nuclei. A model is suggested for the calculation of the competition between complete fusion and quasifission in reactions with heavy nuclei. The fusion rate through the inner fusion barrier in mass asymmetry is found by using the multidimensional Kramers-type stationary solution of the Fokker-Planck equation. The influence of dissipative effects on the dynamics of nuclear fusion is considered.

  19. On the criterion for the optimum choice of a compound nucleus reaction for producing superheavy elements

    International Nuclear Information System (INIS)

    Aroumougame, R.; Gupta, R.K.

    1979-01-01

    The possible reaction partners of a cool compound nucleus reaction for the synthesis of the elements Z = 104, 106 and 108 are studied in terms of the potential energy surfaces, interaction barriers and the nuclear shapes calculated within the frame work of the Fragmentation theory based on two centre shell model. An estimate of the total reaction cross-section suggests that for larger fusion probabilities, the mass and charge asymmetries are the only essential criterion for the optimum choice of a cooler compound nuclear reaction. Larger the mass and charge asymmetries, larger is the fusion cross-section. (auth.)

  20. Synthesis of superheavy elements and application of nuclear physics methods in related fields

    International Nuclear Information System (INIS)

    Flerov, G.

    1985-01-01

    Heavy ion accelerators are used not only for the synthesis of new elements but also for the production of nuclear filters from polymers. The principle is described of the manufacture of such filters, and their chemical processing. By changes in irradiation conditions and in conditions of chemical leaching, nuclear filters may be obtained of various density, shape and size of pores and with a different angular distribution of tracks in the polymer material. The most frequently used polymer is polyethylene terephthalate film. The uses are described of nuclear filters, such as water treatment in the production of semiconductor instruments, in cryogenic instruments, in the purification concentration and sterilization filtration of viruses and vaccines, etc. Other uses of heavy ion beams are suggested, such as the method of nuclear tracks, the manufacture of membranes with a single opening, the manufacture of laser diaphragms, lithography, etc. (E.S.)

  1. On the prospects to detect superheavy elements (SHE) in the earth's crust using the high energy synchrotron radiation and the mass spectrometry

    International Nuclear Information System (INIS)

    Schnier, C.

    2001-01-01

    There are many indications for the existence of superheavy elements (SHE) in the Earth's crust. The appropriate detection methods are X-ray fluorescence (XRF) using the high energy synchrotron radiation and the mass spectrometry. The characteristic X-rays of each element up to Z >120 (corresponding binding energy of the K-electrons E b >230 keV) can be precisely excited with synchrotron XRF. Up to now, the XRF with high energy photons has never been applied to the quest for SHE. New methods of mass spectrometry eg using resonance ionization (RIMS) are promising to detect unambiguously atomic masses about 300 in solid matrices. It is proposed to restart the quest for SHE in the nature. Finding a SHE in the Earth's crust would be very important, because of what it will tell us about the origin of the elements eg about the nucleosynthesis during a super nova explosion, the structure of the atomic nuclei and the site of SHE in the periodic table of elements. (orig.) [de

  2. Fission barriers of superheavy nuclei

    International Nuclear Information System (INIS)

    Burvenich, T.

    2001-01-01

    Full text: Self consistent microscopic mean-field models are powerful tools for the description of nuclear structure phenomena in the region of known elements, where they have reached a good quality. Especially the Skyrme-Hartree-Fock (SHF) method and the Relativistic Mean-Field (RMF) model will be considered in the discussion of the properties of these models. When it comes to extrapolation to the region of superheavy elements, though there is agreement concerning the global trends, these model exhibit significant differences in their predictions concerning fission barrier heights and structures. (Author)

  3. Nuclear treasure island [superheavy nuclei

    CERN Document Server

    CERN. Geneva

    1999-01-01

    Summary form only given. Soon after the experiments at Dubna, which synthesized element 114 and made the first footprints on the beach of the "island of nuclear stability", two new superheavy elements have been discovered at the Lawrence Berkeley National Laboratory. Element 118 and its immediate decay product, element 116, were manufactured at Berkeley's 88 inch cyclotron by fusing targets of lead-208 with an intense beam of 449 MeV krypton-86 ions. Although both new nuclei almost instantly decay into lighter ones, the decay sequence is consistent with theories that have long predicted the island of stability for nuclei with approximately 114 protons and 184 neutrons. Theorist Robert Smolanczuk, visiting from the Soltan Institute for Nuclear Studies in Poland, had calculated that this reaction should have particularly favourable production rates. Now that this route has been signposted, similar reactions could be possible: new elements and isotopes, tests of nuclear stability and mass models, and a new under...

  4. Theoretical description and predictions of the properties of superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sobiczewski, A [Department of Theoretical Physics, Andrzej Soltan Institute for Nuclear Studies (Poland)

    2009-12-31

    Theoretical descriptions of superheavy atomic nuclei are shortly reviewed and illustrated by their results. Such properties of these nuclei as their shapes, masses, fission barriers, decay modes, decay energies, half-lives, are discussed. Special attention is given to the shell structure of the nuclei, due to which they exist. The role of the physical studies of the superheavy nuclei for the chemical research on the superheavy elements and, more generally, the relationship between these two kinds of investigation is underlined. This stresses the importance of close cooperation between physicists and chemists, experimentalists and theoreticians, in these studies.

  5. Gold–superheavy-element interaction in diatomics and cluster adducts: A combined four-component Dirac-Kohn-Sham/charge-displacement study

    Energy Technology Data Exchange (ETDEWEB)

    Rampino, Sergio, E-mail: srampino@thch.unipg.it; Belpassi, Leonardo, E-mail: leonardo.belpassi@cnr.it [Istituto di Scienze e Tecnologie Molecolari, Consiglio Nazionale delle Ricerche c/o Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Via Elce di Sotto 8, 06123 Perugia (Italy); Storchi, Loriano [Dipartimento di Farmacia, Università degli Studi “G. D’Annunzio,” Via dei Vestini 31, 66100 Chieti (Italy)

    2015-07-14

    The chemistry of superheavy elements (Z ≥ 104) is actively investigated in atom-at-a-time experiments of volatility through adsorption on gold surfaces. In this context, common guidelines for interpretation based on group trends in the periodic table should be used cautiously, because relativistic effects play a central role and may cause predictions to fall short. In this paper, we present an all-electron four-component Dirac-Kohn-Sham comparative study of the interaction of gold with Cn (Z = 112), Fl (Z = 114), and Uuo (Z = 118) versus their lighter homologues of the 6th period, Hg, Pb, and Rn plus the noble gas Xe. Calculations were carried out for Au–E (E = Hg, Cn, Pb, Fl, Xe, Rn, Uuo), Au{sub 7}– and Au{sub 20}–E (E = Hg, Cn, Pb, Fl, Rn) complexes, where Au{sub 7} (planar) and Au{sub 20} (pyramidal) are experimentally determined clusters having structures of increasing complexity. Results are analysed both in terms of the energetics of the complexes and of the electron charge rearrangement accompanying their formation. In line with the available experimental data, Cn and more markedly Fl are found to be less reactive than their lighter homologues. On the contrary, Uuo is found to be more reactive than Rn and Xe. Cn forms the weakest bond with the gold atom, compared to Fl and Uuo. The reactivity of Fl decreases with increasing gold-fragment size more rapidly than that of Cn and, as a consequence, the order of the reactivity of these two elements is inverted upon reaching the Au{sub 20}-cluster adduct. Density difference maps between adducts and fragments reveal similarities in the behaviour of Cn and Xe, and in that of Uuo and the more reactive species Hg and Pb. These findings are given a quantitative ground via charge-displacement analysis.

  6. Actinide collisions for QED and superheavy elements with the time-dependent Hartree-Fock theory and the Balian-Vénéroni variational principle

    Directory of Open Access Journals (Sweden)

    Kedziora David J.

    2011-10-01

    Full Text Available Collisions of actinide nuclei form, during very short times of few zs (10−21 s, the heaviest ensembles of interacting nucleons available on Earth. Such collisions are used to produce super-strong electric fields by the huge number of interacting protons to test spontaneous positron-electron pair emission (vacuum decay predicted by the quantum electrodynamics (QED theory. Multi-nucleon transfer in actinide collisions could also be used as an alternative way to fusion in order to produce neutron-rich heavy and superheavy elements thanks to inverse quasifission mechanisms. Actinide collisions are studied in a dynamical quantum microscopic approach. The three-dimensional time-dependent Hartree-Fock (TDHF code tdhf3d is used with a full Skyrme energy density functional to investigate the time evolution of expectation values of one-body operators, such as fragment position and particle number. This code is also used to compute the dispersion of the particle numbers (e.g., widths of fragment mass and charge distributions from TDHF transfer probabilities, on the one hand, and using the BalianVeneroni variational principle, on the other hand. A first application to test QED is discussed. Collision times in 238U+238U are computed to determine the optimum energy for the observation of the vacuum decay. It is shown that the initial orientation strongly affects the collision times and reaction mechanism. The highest collision times predicted by TDHF in this reaction are of the order of ~ 4 zs at a center of mass energy of 1200 MeV. According to modern calculations based on the Dirac equation, the collision times at Ecm > 1 GeV are sufficient to allow spontaneous electron-positron pair emission from QED vacuum decay, in case of bare uranium ion collision. A second application of actinide collisions to produce neutron-rich transfermiums is discussed. A new inverse quasifission mechanism associated to a specific orientation of the nuclei is proposed to

  7. Superheavy elements and decay properties

    Indian Academy of Sciences (India)

    chains from 294118 and, it can be seen that our predictions on the α decay ... The Coulomb and proximity potential model for deformed nuclei (CPPMDN) .... Here the half-life is in seconds, Q-value is in MeV and Z is the atomic number of the.

  8. Superheavy elements and decay properties

    Indian Academy of Sciences (India)

    2015-08-04

    Aug 4, 2015 ... The decay properties of the isotopes of = 115, 117, 118 and 119 have been extensively investigated, focussing on the newly synthesized isotopes within the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The half-lives have also been evaluated using the Viola–Seaborg ...

  9. From heavy nuclei to super-heavy nuclei

    International Nuclear Information System (INIS)

    Theisen, Ch.

    2003-01-01

    The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei. (author)

  10. The extension of the Periodic System: superheavy - superneutronic

    Energy Technology Data Exchange (ETDEWEB)

    Greiner, W [Frankfurt Institute for Advanced Studies, J.W.Goethe University (Germany); Zagrebaev, V [Flerov Laboratory for Nuclear Reactions, Joint Institute for Nuclear Research, Dubna, Moscow Region (Russian Federation)

    2009-12-31

    Nuclear reactions leading to formation of new superheavy elements and isotopes are discussed. The scope and limitations of different nuclear reactions ('cold' and 'hot' synthesis, fusion of fission fragments, transfer reactions and reactions with radioactive ion beams) are analyzed, trying to find most promising reactions which may be used at available facilities.

  11. Perspectives of production of superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Adamian, G. G.; Antonenko, N. V., E-mail: antonenk@theor.jinr.ru; Bezbakh, A. N.; Sargsyan, V. V. [Joint Institute for Nuclear Research, RU–141980 Dubna (Russian Federation); Scheid, W. [Institut für Theoretische Physik der Justus-Liebig-Universität, D–35392 Giessen (Germany)

    2016-07-07

    Possible ways of production of superheavies are discussed. Impact of nuclear structure on the production of superheavy nuclei in complete fusion reactions is discussed. The proton shell closure at Z = 120 is discussed.

  12. Positron creation in superheavy quasi-molecules

    International Nuclear Information System (INIS)

    Mueller, B.

    1976-01-01

    The review of positron creation in superheavy quasi-molecules includes spontaneous positron emission from superheavy atoms, supercritical quasi-molecules, background effects, and some implications of the new ground state. 66 references

  13. First superheavy element experiments at the GSI recoil separator TASCA: The production and decay of element 114 in the 244Pu(48Ca,3-4n) reaction

    International Nuclear Information System (INIS)

    Gates, J. M.; Duellmann, Ch. E.; Schaedel, M.; Ackermann, D.; Block, M.; Bruechle, W.; Essel, H. G.; Hartmann, W.; Hessberger, F. P.; Huebner, A.; Jaeger, E.; Khuyagbaatar, J.; Kindler, B.; Krier, J.; Kurz, N.; Lommel, B.; Schaffner, H.; Schausten, B.; Schimpf, E.; Steiner, J.

    2011-01-01

    Experiments with the new recoil separator, Transactinide Separator and Chemistry Apparatus (TASCA), at the GSI were performed by using beams of 48 Ca to irradiate targets of 206-208 Pb, which led to the production of 252-254 No isotopes. These studies allowed for evaluation of the performance of TASCA when coupled to a new detector and electronics system. By following these studies, the isotopes of element 114 ( 288-291 114) were produced in irradiations of 244 Pu targets with 48 Ca beams at compound nucleus excitation energies around 41.7 and 37.5 MeV, demonstrating TASCA's ability to perform experiments with picobarn-level cross sections. A total of 15 decay chains were observed and were assigned to the decay of 288-291 114. A new α-decay branch in 281 Ds was observed, leading to the new nucleus 277 Hs.

  14. The Transplutonium. The superheavy nuclei found in the micas of Madagascar and their interests

    International Nuclear Information System (INIS)

    Raoelina Andriambololona

    1976-01-01

    Since June 1976, evidence for the existence of superheavy elements is discussed about. After having recalled artificial elements with atomic numbers Z of wich go from Z=95 (Americium) to Z=107 (built in 1976), superheavy elements having Z greater than 110 are considered. They have been discovered by american searchers in giant halos seen in Madagascar micas. The samples have been recoked in the Fort-Dauphin region (Haut Mandrare). The corresponding numbers Z are 114, 115, 116, 124, 125, 125, 126, 127. It seems that the existence of Z=126 element should be accepted with a greater degree of confidence. But different experiences done by other groups seem to show the evidence of superheavy elements in micas looks weaker. Nevertheless, it is interesting to investigate the evidence or the non-evidence of those elements. We estimate the mass numbers A of those superheavy elements in the liquid drop model if we assume that they are stable versus β. The results thus obtained agree with the shell-model ones within 4 % approximation. We propose if the evidence of superheavies is confirmed to give the name of madagascarium to one of them (Z=126) by similitude with francium, lutetium, polonium, berkelium, americium, europium, ...Their evidence was first conjectured in Madagascar micas in 1976. Superheavy nuclei are to be distinguished from hypernuclei. [fr

  15. Stability and production of superheavy nuclei

    International Nuclear Information System (INIS)

    Moeller, P.; Los Alamos National Lab., NM; Nix, J.R.

    1997-01-01

    Beyond uranium heavy elements rapidly become increasingly unstable with respect to spontaneous fission as the proton number Z increases, because of the disruptive effect of the long-range Coulomb force. However, in the region just beyond Z = 100 magic proton and neutron numbers and the associated shell structure enhances nuclear stability sufficient to allow observation of additional nuclei. Some thirty years ago it was speculated that an island of spherical, relatively stable superheavy nuclei would exist near the next doubly magic proton-neutron combination beyond 208 Pb, that is, at proton number Z 114 and neutron number N = 184. Theory and experiment now show that there also exists a rock of stability in the vicinity of Z = 110 and N = 162 between the actinide region, which previously was the end of the peninsula of known elements, and the predicted island of spherical superheavy nuclei slightly southwest of the magic numbers Z = 114 and N = 184. The authors review here the stability properties of the heavy region of nuclei. Just as the decay properties of nuclei in the heavy region depend strongly on shell structure, this structure also dramatically affects the fusion entrance channel. The six most recently discovered new elements were all formed in cold-fusion reactions. They discuss here the effect of the doubly magic structure of the target in cold-fusion reactions on the fusion barrier and on dissipation

  16. Stability of superheavy nuclei

    Science.gov (United States)

    Pomorski, K.; Nerlo-Pomorska, B.; Bartel, J.; Schmitt, C.

    2018-03-01

    The potential-energy surfaces of an extended set of heavy and superheavy even-even nuclei with 92 ≤Z ≤126 and isospins 40 ≤N -Z ≤74 are evaluated within the recently developed Fourier shape parametrization. Ground-state and decay properties are studied for 324 different even-even isotopes in a four-dimensional deformation space, defined by nonaxiality, quadrupole, octupole, and hexadecapole degrees of freedom. Nuclear deformation energies are evaluated in the framework of the macroscopic-microscopic approach, with the Lublin-Strasbourg drop model and a Yukawa-folded mean-field potential. The evolution of the ground-state equilibrium shape (and possible isomeric, metastable states) is studied as a function of Z and N . α -decay Q values and half-lives, as well as fission-barrier heights, are deduced. In order to understand the transition from asymmetric to symmetric fission along the Fm isotopic chain, the properties of all identified fission paths are investigated. Good agreement is found with experimental data wherever available. New interesting features about the population of different fission modes for nuclei beyond Fm are predicted.

  17. Problem of ''deformed'' superheavy nuclei

    International Nuclear Information System (INIS)

    Sobiczewski, A.; Patyk, Z.; Muntian, I.

    2000-08-01

    Problem of experimental confirmation of deformed shapes of superheavy nuclei situated in the neighbourhood of 270 Hs is discussed. Measurement of the energy E 2+ of the lowest 2+ state in even-even species of these nuclei is considered as a method for this confirmation. The energy is calculated in the cranking approximation for heavy and superheavy nuclei. The branching ratio p 2+ /p 0+ between α decay of a nucleus to this lowest 2+ state and to the ground state 0+ of its daughter is also calculated for these nuclei. The results indicate that a measurement of the energy E 2+ for some superheavy nuclei by electron or α spectroscopy is a promising method for the confirmation of their deformed shapes. (orig.)

  18. A pilgrimage through superheavy valley

    Indian Academy of Sciences (India)

    gap p, average neutron pairing gap n, two-nucleon separation energy S2q and shell .... study has appeared as a powerful tool to study the shapes and collective properties of nuclei ... and identify the magic proton and neutron numbers in the superheavy region. ... pairing gap indicates the close shell structure of the nucleus.

  19. Quest for superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Heenen, P.H. [Universite Libre de Bruxelles, Service de Physique Nucleaire Theorique (Belgium); Nazarewicz, W. [Tennessee Univ., Knoxville, TN (United States). Dept. of Physics; Warsaw Univ. (Poland). Inst. Fizyki Teoretycznej

    2002-02-01

    This article draws the long history of the discovery of new heavy nuclei since its beginning in 1940 when neptunium was found, and presents the current status of research in this field. The last 3 years have brought a number of experimental surprises which have truly rejuvenated the field. In January 1999, scientists from Dubna (Russia) reported the synthesis of 1 atom of element 114 ({sup 298}Uuq) in a hot fusion reaction between a {sup 48}Ca beam and a {sup 244}Pu target. This discovery was followed by 3 other reports from Dubna. First using the {sup 242}Pu({sup 48}Ca,3n) reaction, they produced {sup 287}Uuq. In 1999 the synthesis of another isotope of Z=114, the even-even {sup 288}Uuq was reported. The element Z=116 ({sup 292}Uuh) was discovered as a product of the {sup 248}Cm({sup 48}Ca,4n) reaction. The GSI (Germany) group found a new even isotope of the element 110: {sup 270}Uun and also {sup 272}Uuu (element 111) and {sup 277}Uub (element 112). 2 new isotopes of the element 107: {sup 266}Bh and {sup 267}Bh have been found at Berkeley (Usa). The synthesis of the new element Z=118 ({sup 293}Uuo) announced in 1999 by the Berkeley group was retracted 2 years later. The lifetimes reported for the elements {sup 284}Uub and {sup 280}Uun are by many orders of magnitude longer than those of the isotopes with Z{<=}112 previously discovered at GSI. (A.C.)

  20. Superheavy research at RIKEN

    International Nuclear Information System (INIS)

    Morita, Kosuke

    2010-01-01

    At RIKEN, Japan, we performed experiments to study the productions and decays of the heaviest elements produced by 208 Pb- and 209 Bi- based 'cold fusion' reactions. A gas-filled recoil separator GARIS was used for the study. In the study of 209 Bi( 70 Zn, n) reaction, we observed two decay chains originating from an isotope of the 113th element, 178 113, which were assigned firstly by generic correlation of the alpha decay chains connected into the previously known decay of 266 Bh and 262 Db via previously unknown alpha decays of 278 113, 274 Rg, and 270 Mt. In addition, decay properties of an isotope 266 Bh and its daughter nucleus 262 Db produced by the 248 Cm( 23 Na, 5n) reaction were studied. 266 Bh was clearly identified from the correlation of the known nuclide, 262 Db, providing further confirmation of the discovery of 278 113.

  1. From heavy nuclei to super-heavy nuclei; Des noyaux lourds aux super-lourds

    Energy Technology Data Exchange (ETDEWEB)

    Theisen, Ch

    2003-01-01

    The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei. (author)

  2. The RIKEN gas-filled recoil separator and a possible new approach to superheavy elements by the (HI, αxn) reaction

    International Nuclear Information System (INIS)

    Nomura, T.

    1990-10-01

    The (HI, αxn) reaction, in which precompound α particle emission takes place, is shown to occur significantly even near the Coulomb barrier. Because the α emission can efficiently cool down a highly excited nucleus both in energy and angular momentum, it is considered to be very effective for production of heavy elements like SHE. However, the angular distributions of residual nuclei produced in this reaction are side-peaked, requiring a recoil-type separator with large angular acceptance when it is applied for collection of the relevant nuclei. A brief description is given about a gas-filled separator recently constructed at RIKEN, which meets the above requirement. (author)

  3. The Peculiarities of the Production and Decay of Superheavy Nuclei

    International Nuclear Information System (INIS)

    Itkis, M. G.; Bogachev, A. A.; Itkis, I. M.; Jandel, M.; Kliman, J.; Knyazheva, G. N.; Kondratiev, N. A.; Kozulin, E. M.; Krupa, L.; Oganessian, Yu. Ts.; Pokrovsky, I. V.; Prokhorova, E. V.; Rusanov, A. Ya.; Sagaidak, R. N.; Beghini, S.; Montagnoli, G.; Scarlassara, F.; Behera, B. R.; Corradi, L.; Fioretto, E.

    2006-01-01

    The interest in the study of the fission process of superheavy nuclei mainly deals with the opportunity to obtain information about the cross-section of the compound nucleus (CN) formation at excitation energies E*≅15-30 MeV. It allows one to estimate the survival probability of the superheavy composite system after evaporation of 1-3 neutrons, i.e. in 'cold' or 'warm' fusion reactions. However, in order to solve this problem deeper understanding of the coalescence processes between colliding nuclei, the competition between fusion-fission and quasi-fission processes is needed. The characteristics of both processes, their manifestation in the experimental observables and the relative contribution to the capture cross-section in dependence on the excitation energies, reaction entrance channel etc were investigated for a wide range of target-projectile combinations. Results of the experiments devoted to the study of the fusion-fission and quasi-fission processes in the reactions of the formation of the superheavy nuclei with Z = 102-122 are presented. The heavy ions 26Mg, 48Ca, 50Ti, 58Fe and 64Ni were used as projectiles. The choice of the reactions with 48Ca and actinide-targets was inspired by the experiments on the production of the isotopes 283112, 289114 and 283116 in Dubna using the same reactions. The 50Ti, 58Fe and 64Ni projectiles were chosen since the corresponding projectile-target combinations lead to the synthesis of even heavier elements. The experiments were carried out at the U-400 accelerator of the Flerov Laboratory of Nuclear Reactions (JINR, Russia) and the XTU Tandem accelerator of the National Laboratory of Legnaro (LNL, Italy) using the time-of-flight spectrometer of fission fragments CORSET. The role of the shell effects, the influence of the entrance channel asymmetry and the deformations of colliding nuclei on the mechanism of the fusion-fission and the competitive process of quasi-fission are discussed. The recent results on synthesis of

  4. New elements

    International Nuclear Information System (INIS)

    Flerov, G.

    1976-01-01

    The history is briefly described of the investigation of superheavy elements at the Joint Institute for Nuclear Research at Dubna. The significance of the investigation is assessed from the point of view of the nuclear structure study and major problems encountered in experimental efforts are indicated. Current experimental methods aiming at the discovery or the production of superheavy nuclei with Z approximately 114 are listed. (I.W.)

  5. Systematical calculations on the ground state properties of heavy and superheavy nuclei

    International Nuclear Information System (INIS)

    Ren, Z.Z.; Center of Theoretical Nuclear Physics, Lanzhou; Mao, Y.C.; Zhi, Q.J.; Xu, C.; Dong, T.K.

    2007-01-01

    The synthesis of superheavy elements is now a hot topic in nuclear physics. Alpha-decay and spontaneous fission are two main decay modes in heavy and superheavy regions. Theoretical studies on alpha radioactivity and spontaneous fission can provide useful information for experiments. We investigate the alpha-decay and spontaneous fission of heavy and superheavy nuclei with different models. This includes the alpha-decay energies, alpha decay half-lives, and half-lives of spontaneous fission. The theoretical alpha-decay half-lives are in good agreement with experimental ones. The calculated half-lives of spontaneous fission are in reasonable agreement with present data. The properties of unknown nuclei are predicted. (author)

  6. Swimming back from the superheavy island

    International Nuclear Information System (INIS)

    Draculis, G.

    1999-01-01

    What's next in the series 108, 109, 110, 111, 112?The answer a couple of years ago looked like being not much. But major ripples are spreading in the Nuclear Physics community as news of the recent discoveries of the Superheavy element Z=118 and its daughters Z=116 and Z=114 was announced by a Berkeley group led by Victor Ninov [1]. Several pieces of news about Z=114 from studies at Dubna promoted by Yuri Oganessian [2,3] were circulating at about the same time.The 'not much' answer was because increasingly heroic efforts seemed to be needed to produce and identify each heavier element in the series. The problem is that such nuclei, if they exist in a stable or quasi-stable form are prone to fission, and so are any nuclei one might conceive as making to provide a path to one's nucleus of choice. The favoured reaction process used to make them is heavy-ion fusion which involves bombarding target nuclei of 208 PB (proton number Z=82), 238 U (Z=92) or even 244 Pu (Z=94) with medium weight (and relatively neutron-rich) beams such as 48 Ca (Z=20) and 86 Kr (Z=36) nuclei, accelerated to energies near or just above the Coulomb barrier, with the hope of the two nuclei overlapping and combining because of the highly attractive (strong) nuclear force. The catch is that putting sufficient energy in to get the nuclei together leaves the compound nucleus with excitation energy and spin, which dramatically increase its probability to fission, and therefore not survive further. As you go lower in beam energy, the probability for the initial fusion drops precipitously since the nuclei have to tunnel through a potential barrier caused by the repulsive Coulomb force between the nuclear charges, in order to make contact. Somewhere between the dramatically falling probability for fusion and steeply increasing probability for fission might be a window of production and survival

  7. Superheavy nuclei: a relativistic mean field outlook

    International Nuclear Information System (INIS)

    Afanasjev, A.V.

    2006-01-01

    The analysis of quasi-particle spectra in the heaviest A∼250 nuclei with spectroscopic data provides an additional constraint for the choice of effective interaction for the description of superheavy nuclei. It strongly suggests that only the parametrizations which predict Z = 120 and N = 172 as shell closures are reliable for superheavy nuclei within the relativistic mean field theory. The influence of the central depression in the density distribution of spherical superheavy nuclei on the shell structure is studied. A large central depression produces large shell gaps at Z = 120 and N = 172. The shell gaps at Z = 126 and N = 184 are favoured by a flat density distribution in the central part of the nucleus. It is shown that approximate particle number projection (PNP) by means of the Lipkin-Nogami (LN) method removes pairing collapse seen at these gaps in the calculations without PNP

  8. Half-life predictions for decay modes of superheavy nuclei

    International Nuclear Information System (INIS)

    Duarte, S.B.; Tavares, O.A.P.; Goncalves, M.; Rodriguez, O.; Guzman, F.; Barbosa, T.N.; Garcia, F.; Dimarco, A.

    2004-09-01

    We applied the Effective Liquid Drop Model (ELDM) to predict the alpha-decay, cluster emission and cold fission half-life-values of nuclei in the region of Superheavy Elements (SHE). The present calculations have been made in the region of the ZN-plane defined by 155 <=N <=220 and 110<=Z<=135. Shell effects are included via the Q-value of the corresponding decay case. We report the results of a systematic calculation of the half-life for the three nuclear decay modes in a region of the ZN-plane where superheavy elements are expected to be found. Results have shown that, among the decay modes investigated here, the alpha decay is the dominant one. i.e, the decay mode of smallest half-lives. Half-life predictions for alpha decay, cluster emission and cold fission for the isotopic family of the most recent SHE detected of Z=115 and for the isotopic family of the already consolidated SHE of Z=111 are presented. (author)

  9. Collective motion in hot superheavy nuclei

    NARCIS (Netherlands)

    Tveter, TS; Gaardhoje, JJ; Maj, A; Ramsoy, T; Atac, A; Bacelar, J; Bracco, A; Buda, A; Camera, F; Herskind, B; Korten, W; Krolas, W; Menthe, A; Million, B; Nifenecker, H; Pignanelli, M; Pinston, JA; vanderPloeg, H; Schussler, F; Sletten, G

    1996-01-01

    The superheavy nucleus (272)(108)Hs and its evaporation daughters have been produced using the reaction Th-232(Ar-40,gamma xn) with beam energies 10.5 and 15.0 MeV/A. The Giant Dipole Resonance gamma-radiation from the hot conglomerate system prior to fission has been isolated using a differential

  10. Decay of heavy and superheavy nuclei

    Indian Academy of Sciences (India)

    April 2014 physics pp. 705–715. Decay of heavy and superheavy nuclei ... study on the feasibility of observing α decay chains from the isotopes of the ... studies on 284−286115 and 288−292117 will be a guide to future experiments. .... ratio of the α decay from the ground state of the parent nucleus to the level i of the.

  11. Superheavy nuclei – cold synthesis and structure

    Indian Academy of Sciences (India)

    120 and Ж = 172 or 184, for superheavy nuclei. This result is discussed in ... 1980 [7] on the basis of the QMFT, once again prior to its observation in 1984. Thus, cold ... On the other hand, based on a rather complete deformed relativistic mean field (DRMF) calculation, using the NL1 parameter set, we [16] predicted. = 120.

  12. α-decay chains and cluster-decays of superheavy 269-27110 nuclei

    International Nuclear Information System (INIS)

    Sushil Kumar; Rajesh Kumar; Balasubramaniam, M.; Gupta, Raj K.

    2001-01-01

    Due to the availability of radioactive nuclear beams (RNB) and the advancement in accelerator technology, it is now possible to synthesize very heavy elements (Z> 100), called superheavy elements. It is a well established fact that these superheavy elements, due to their shorter lifetime, decay via successive alpha emissions and at a later stage undergo spontaneous fission. Several such decay chains are now observed. An attempt is made to fit all such known decay chains and the results of the three observed α-decay chains of Z=110 ( 269-271 10) nuclei are presented. The model used is the preformed cluster model (PCM). Also, an attempt is made for the first time to find the possibility of any branching to heavy-cluster emissions in these chains

  13. In-beam separation and mass determination of superheavy nuclei

    International Nuclear Information System (INIS)

    Malyshev, O.N.; Eremin, A.V.; Popeko, A.G.

    2003-01-01

    Within the past fifteen years, the recoil separator VASSILISSA has been used for the investigations of evaporation residues produced in complete fusion reactions induced by heavy ions. The study of decay properties and formation cross sections of the isotopes of elements 110, 112 and 114 was performed using high intensity 48 Ca beams and 232 Th, 238 U, 242 Pu targets. For further experiments aimed at the synthesis of the superheavy element isotopes (Z≥110) with the use of intense 48 Ca extracted beams, improvements in the ion optical system of the separator and the focal plane detector system have been made. The results from the test reactions and new result for the isotope 283 112 are presented

  14. A systematic study of superheavy nuclei for Z = 114 and beyond using the relativistic mean field approach

    International Nuclear Information System (INIS)

    Patra, S.K.; Wu, Cheng-Li; Praharaj, C.R.; Gupta, Raj K.

    1999-01-01

    We have studied the structural properties of even-even, neutron deficient, Z=114-126, superheavy nuclei in the mass region A ∼ 270-320, using an axially deformed relativistic mean field model. The calculations are performed with three parameter sets (NL1, TM1 and NL-SH), in order to see the dependence of the structural properties on the force used. The calculated ground state shapes are found to be parameter dependent. For some parameter sets, many of the nuclei are degenerate in their ground state configuration. Special attention is given to the investigation of the magic structures (spherical shell closures) in the superheavy region. We find that some known magic numbers are absent and new closed shells are predicted. Large shell gaps appear at Z=80, 92, (114), 120 and 138, N=138, (164), (172), 184, (198), (228) and 258, irrespective of the parameter sets used. The numbers in parenthesis are those which correspond to relatively smaller gaps. The existence of new magic numbers in the valley of superheavy elements is discussed. It is suggested that nuclei around Z=114 and N = 164 ∼ 172 could be considered as candidates for the next search of superheavy nuclei. The existence of superheavy islands around Z=120 and N=172 or N 184 double shell closure is also discussed

  15. Exotic decay modes of odd-Z (105-119) superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Rajeswari, N.S. [Bharathiar University, Department of Physics, Coimbatore (India); Avinashilingam Institute for Home Science and Higher Education for Women - University, Department of Physics, Coimbatore (India); Balasubramaniam, M. [Bharathiar University, Department of Physics, Coimbatore (India)

    2014-06-15

    Half-lives of proton emission for proton emitters with Z = 51 to 83 are calculated, in the frame-work of unified fission model with the penetrability calculated using the WKB approximation. For all the ground and isomeric state of the proton, the deformation degree of freedom is included. Calculated half-lives are in good agreement with the experimental ones. Experimentally for a few isotopes, proton and alpha branches are reported. Hence we have calculated the half-lives of alpha decay for these elements. For parent nuclei {sup 157}Ta, {sup 166}Ir, {sup 167}Ir, {sup 176}Tl and {sup 177}Tl, the alpha decay mode is preferred over the proton emission. Further, the calculations are extended to find half-lives of superheavy element with odd proton number in the range Z = 105 to 119, for both proton, alpha and for a few cluster decays. Calculations on superheavy elements reveal that cluster radioactivity has half-lives comparable with proton emissions. It is found that proton emission is the primary competing decay mode with respect to alpha decay for superheavy elements. Among considered clusters, {sup 12}C, {sup 20}Ne and {sup 24}Mg are found to have lowest half-lives among other N = Z clusters and for a few clusters the half-lives are found to be comparable with that of proton emission. (orig.)

  16. Fusion-fission probabilities, cross sections, and structure notes of superheavy nuclei

    International Nuclear Information System (INIS)

    Kowal, Michał; Cap, Tomasz; Jachimowicz, Piotr; Skalski, Janusz; Siwek-Wilczyńska, Krystyna; Wilczyński, Janusz

    2016-01-01

    Fusion – fission probabilities in the synthesis of heaviest elements are discussed in the context of the latest experimental reports. Cross sections for superheavy nuclei are evaluated using the “Fusion by Diffusion” (FBD) model. Predictive power of this approach is shown for experimentally known Lv and Og isotopes and predictions given for Z = 119, 120. Ground state and saddle point properties as masses, shell corrections, pairing energies, and deformations necessary for cross-section estimations are calculated systematically within the multidimensional microscopic-macroscopic method based on the deformed Woods-Saxon single-particle potential. In the frame of the FBD approach predictions for production of elements heavier than Z = 118 are not too optimistic. For this reason, and because of high instability of superheavy nuclei, we comment on some structure effects, connected with the K-isomerism phenomenon which could lead to a significant increase in the stability of these systems.

  17. Remarks on the fission barriers of super-heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, S. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Goethe-Universitaet Frankfurt, Institut fuer Physik, Frankfurt (Germany); Heinz, S.; Mann, R.; Maurer, J.; Muenzenberg, G.; Barth, W.; Dahl, L.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Runke, J.; Scheidenberger, C.; Tinschert, K. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Antalic, S. [Comenius University, Department of Nuclear Physics and Biophysics, Bratislava (Slovakia); Eberhardt, K.; Thoerle-Pospiech, P.; Trautmann, N. [Johannes Gutenberg-Universitaet Mainz, Mainz (Germany); Grzywacz, R. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Tennessee, Knoxville, TN (United States); Hamilton, J.H. [Vanderbilt University, Department of Physics and Astronomy, Nashville, TN (United States); Henderson, R.A.; Kenneally, J.M.; Moody, K.J.; Shaughnessy, D.A.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Miernik, K. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Warsaw, Warsaw (Poland); Miller, D. [University of Tennessee, Knoxville, TN (United States); Morita, K. [RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama (Japan); Nishio, K. [Japan Atomic Energy Agency, Tokai, Ibaraki (Japan); Popeko, A.G.; Yeremin, A.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Roberto, J.B.; Rykaczewski, K.P. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Uusitalo, J. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland)

    2016-04-15

    Shell-correction energies of super-heavy nuclei are approximated by using Q{sub α} values of measured decay chains. Five decay chains were analyzed, which start at the isotopes {sup 285}Fl, {sup 294}118, {sup 291}Lv, {sup 292}Lv and {sup 293}Lv. The data are compared with predictions of macroscopic-microscopic models. Fission barriers are estimated that can be used to eliminate uncertainties in partial fission half-lives and in calculations of evaporation-residue cross-sections. In that calculations, fission probability of the compound nucleus is a major factor contributing to the total cross-section. The data also provide constraints on the cross-sections of capture and quasi-fission in the entrance channel of the fusion reaction. Arguments are presented that fusion reactions for synthesis of isotopes of elements 118 and 120 may have higher cross-sections than assumed so far. (orig.)

  18. Alpha-decay chains of superheavy nuclei 292-296118

    Science.gov (United States)

    Singh, U. K.; Kumawat, M.; Saxena, G.; Kaushik, M.; Jain, S. K.

    2018-05-01

    We have employed relativistic mean-field plus BCS (RMF+BCS) approach for the study of even-even superheavy nuclei with Z = 118 which is the last and recent observed element in the periodic chart so far. Our study includes binding energies, Qα values, alpha-decay half-lives and spontaneous decay half-lives along with comparison of available experimental data and the results of FRDM calculations. We find an excellent match with the only known decay chain of 294118 for Z = 118 so far and predict decay chain of 292118 and 296118 in consistency with known experimental decay chains and FRDM results. These results may provide a very helpful insight to conduct experiments for realizing the presence of nuclei with Z = 118.

  19. Toroidal Superheavy Nuclei in Skyrme-Hartree-Fock Approach

    International Nuclear Information System (INIS)

    Staszczak, A.; Wong, Cheuk-Yin

    2009-01-01

    Within the self-consistent constraint Skyrme-Hartree-Fock+BCS model (SHF+BCS), we found equilibrium toroidal nuclear density distributions in the region of superheavy elements. For nuclei with a sufficient oblate deformation (Q 20 < -200 b), it becomes energetically favorable to change the genus of nuclear surface from 0 to 1, i.e., to switch the shape from a biconcave disc to a torus. The energy of the toroidal (genus=1) SHF+BCS solution relative to the compact (genus=0) ground state energy is strongly dependent both on the atomic number Z and the mass number A. We discuss the region of Z and A where the toroidal SHF+BCS total energy begins to be a global minimum

  20. Transactinide elements

    International Nuclear Information System (INIS)

    Hemingway, J.D.

    1975-01-01

    The review is covered in sections, entitled: predicted nuclear properties - including closed shells, decay characteristics; predicted chemical properties - including electronic structure and calculated properties, X-radiation, extrapolated chemical properties, separation chemistry; methods of synthesis; the natural occurrence of superheavy elements. (U.K.)

  1. Gravitational production of superheavy dark matter

    International Nuclear Information System (INIS)

    Chung, Daniel J. H.; Crotty, Patrick; Kolb, Edward W.; Riotto, Antonio

    2001-01-01

    The dark matter in the universe can be in the form of a superheavy matter species (wimpzilla). Several mechanisms have been proposed for the production of wimpzilla particles during or immediately following the inflationary epoch. Perhaps the most attractive mechanism is through gravitational particle production, where particles are produced simply as a result of the expansion of the universe. In this paper we present a detailed numerical calculation of wimpzilla gravitational production in hybrid-inflation models and natural-inflation models. Generalizing these findings, we also explore the dependence of the gravitational production mechanism on various models of inflation. We show that superheavy dark matter production seems to be robust, with Omega X h 2 ∼(M X /10 11 GeV) 2 (T RH /10 9 GeV), so long as M X I , where M X is the wimpzilla mass, T RH is the reheat temperature, and H I is the expansion rate of the universe during inflation

  2. On the thermalization achieved in the reactions involving superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Bansal, Rajni [Department of Physics, MCM DAV College for Women, Sector 36A, Chandigarh-160036, India rajnibansal.pu@gmail.com (India)

    2016-05-06

    In the present study, we aim to explore the role of Coulomb potential on the thermalization achieved in the reactions involving superheavy nuclei. Particularly, we shall study the degree of the equilibrium attained in a reaction by the 3D density plots, anisotropy ratio as well as by the rapidity distribution of the nucleons. Our study reveals that the degree of the equilibrium attained in the central reactions of the superheavy nuclei remains unaffected by the Coulomb potential.

  3. Superheavy magnetic monopoles and the standard cosmology

    International Nuclear Information System (INIS)

    Turner, M.S.

    1984-10-01

    The superheavy magnetic monopoles predicted to exist in grand unified theories (GUTs) are very interesting obsects, both from the point of view of particle physics, as well as from astrophysics and cosmology. Astrophysical and cosmological considerations have proved to be invaluable in studying the properties of GUT monopoles. Because of the glut of monopoles predicted in the standard cosmology for the simplest GUTs (so many that the Universe should have reached a temperature of 3 0 K at the tender age of approx. = 10,000 yrs), the simplest GUTs and the standard cosmology are not compatible. This is a very important piece of information about physics at unification energies (E greater than or equal to 10 14 GeV) and about the earliest moments (t less than or equal to 10 -34 s) of the Universe. In this talk the author reviews the cosmological consequences of GUT monopoles within the context of the standard hot big bang model. 46 references

  4. Superheavy thermal dark matter and primordial asymmetries

    Energy Technology Data Exchange (ETDEWEB)

    Bramante, Joseph [Perimeter Institute for Theoretical Physics,31 Caroline St N, Waterloo, ON N2L 2Y5 (Canada); Unwin, James [Department of Physics, University of Illinois at Chicago,845 W Taylor St, Chicago, IL 60607 (United States)

    2017-02-23

    The early universe could feature multiple reheating events, leading to jumps in the visible sector entropy density that dilute both particle asymmetries and the number density of frozen-out states. In fact, late time entropy jumps are usually required in models of Affleck-Dine baryogenesis, which typically produces an initial particle-antiparticle asymmetry that is much too large. An important consequence of late time dilution, is that a smaller dark matter annihilation cross section is needed to obtain the observed dark matter relic density. For cosmologies with high scale baryogenesis, followed by radiation-dominated dark matter freeze-out, we show that the perturbative unitarity mass bound on thermal relic dark matter is relaxed to 10{sup 10} GeV. We proceed to study superheavy asymmetric dark matter models, made possible by a sizable entropy injection after dark matter freeze-out, and identify how the Affleck-Dine mechanism would generate the baryon and dark asymmetries.

  5. Superheavy thermal dark matter and primordial asymmetries

    International Nuclear Information System (INIS)

    Bramante, Joseph; Unwin, James

    2017-01-01

    The early universe could feature multiple reheating events, leading to jumps in the visible sector entropy density that dilute both particle asymmetries and the number density of frozen-out states. In fact, late time entropy jumps are usually required in models of Affleck-Dine baryogenesis, which typically produces an initial particle-antiparticle asymmetry that is much too large. An important consequence of late time dilution, is that a smaller dark matter annihilation cross section is needed to obtain the observed dark matter relic density. For cosmologies with high scale baryogenesis, followed by radiation-dominated dark matter freeze-out, we show that the perturbative unitarity mass bound on thermal relic dark matter is relaxed to 10 10 GeV. We proceed to study superheavy asymmetric dark matter models, made possible by a sizable entropy injection after dark matter freeze-out, and identify how the Affleck-Dine mechanism would generate the baryon and dark asymmetries.

  6. Superheavy dark matter through Higgs portal operators

    Science.gov (United States)

    Kolb, Edward W.; Long, Andrew J.

    2017-11-01

    The WIMPzilla hypothesis is that the dark matter is a super-weakly-interacting and superheavy particle. Conventionally, the WIMPzilla abundance is set by gravitational particle production during or at the end of inflation. In this study we allow the WIMPzilla to interact directly with Standard Model fields through the Higgs portal, and we calculate the thermal production (freeze-in) of WIMPzilla dark matter from the annihilation of Higgs boson pairs in the plasma. The two particle-physics model parameters are the WIMPzilla mass and the Higgs-WIMPzilla coupling. The two cosmological parameters are the reheating temperature and the expansion rate of the universe at the end of inflation. We delineate the regions of parameter space where either gravitational or thermal production is dominant, and within those regions we identify the parameters that predict the observed dark matter relic abundance. Allowing for thermal production opens up the parameter space, even for Planck-suppressed Higgs-WIMPzilla interactions.

  7. Physics of superheavy dark matter in supergravity

    Science.gov (United States)

    Addazi, Andrea; Marciano, Antonino; Ketov, Sergei V.; Khlopov, Maxim Yu.

    New trends in inflationary model building and dark matter production in supergravity are considered. Starobinsky inflation is embedded into 𝒩 = 1 supergravity, avoiding instability problems, when the inflaton belongs to a vector superfield associated with a U(1) gauge symmetry, instead of a chiral superfield. This gauge symmetry can be spontaneously broken by the super-Higgs mechanism resulting in a massive vector supermultiplet including the (real scalar) inflaton field. Both supersymmetry (SUSY) and the R-symmetry can also be spontaneously broken by the Polonyi mechanism at high scales close to the inflationary scale. In this case, Polonyi particles and gravitinos become superheavy, and can be copiously produced during inflation by the Schwinger mechanism sourced by the universe expansion. The Polonyi mass slightly exceeds twice the gravitino mass, so that Polonyi particles are unstable and decay into gravitinos. Considering the mechanisms of superheavy gravitino production, we find that the right amount of cold dark matter composed of gravitinos can be achieved. In our scenario, the parameter space of the inflaton potential is directly related to the dark matter one, providing a new unifying framework of inflation and dark matter genesis. A multi-superfield extension of the supergravity framework with a single (inflaton) superfield can result in a formation of primordial nonlinear structures like mini- and stellar-mass black holes, primordial nongaussianity, and the running spectral index of density fluctuations. This framework can be embedded into the SUSY GUTs inspired by heterotic string compactifications on Calabi-Yau three-folds, thus unifying particle physics with quantum gravity.

  8. Fission times studies of the Z=124 superheavy nucleus by X-ray fluorescence

    International Nuclear Information System (INIS)

    Airiau, Maud

    2016-01-01

    Since the 1960's nuclear structure model have predicted the existence of an island of stability of superheavy elements. It should be located around the next magic numbers expected at N=172 or 184 and between Z=114 and 126 depending on the model. Very high fission barrier of a few MeV are predicted to be generated by microscopic effects for those nuclei for which large fission times distributions extended to very high fission times are induced. Fission time measurements of the superheavy element Z=124 have been made by us using the X-ray fluorescence technique, a method based on the filling of inner-shell electronic vacancies created during the collision leading to the formation of the compound nucleus. The aim of this experiment was to detect in coincidence both fission fragments and characteristic X-rays from the Z=124, created by the reaction 238 U+ 70,76 Ge. The main difficulty was to identify those X-rays due to the fact that gamma-rays from fission fragments were emitted in the same energy range, which affected our photon multiplicities for any fragment selection. This new difficulty brings an important limitation to the study of some particular superheavy elements by the X-ray fluorescence method. K X-rays spectra have been simulated using MCDF (Multi-Configuration-Dirac-Fock) and then compared to the experimental ones in order to get a maximal K X-ray multiplicity compatible with our data. The extracted results were about 6-7% for 76 Ge and from 12 to 14% for 70 Ge. Those values remain compatible with the experimental signature of long lifetime component observed for the same system but using a blocking technique in single crystals. (author) [fr

  9. Decay properties of {sup 256-339}Ds superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Santhosh, K.P.; Nithya, C. [Kannur University, School of Pure and Applied Physics, Payyanur, Kerala (India)

    2017-09-15

    The decay properties of 84 isotopes of darmstadtium superheavy nuclei (Z = 110) have been studied using various theoretical models. The proton emission half-lives, the alpha decay half-lives, the spontaneous fission half-lives and the cluster decay half-lives of all the isotopes are evaluated. The one-proton emission half-lives and the alpha decay half-lives are predicted using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The calculated alpha half-lives are compared with the available experimental results as well as with the predictions of other theoretical models. The predicted half-lives matches well with the experimental results. The one-proton half-lives are also compared with the predictions using other formalisms. The shell-effect-dependent formula of Santhosh et al. has been employed for calculating the spontaneous fission half-lives. A theoretical comparison of spontaneous fission half-lives with four different formalisms is performed. By comparing the one-proton emission half-lives, the alpha decay half-lives and the spontaneous fission half-lives decay modes are predicted for all the isotopes of Ds. It is seen that the isotopes within the range 256 ≤ A ≤ 263 and 279 ≤ A ≤ 339 decay through spontaneous fission and the isotopes 264 ≤ A ≤ 278 exhibit alpha decay. Cluster decay half-lives are calculated using different models including the Coulomb and proximity potential (CPPM), for determining the magicities in the superheavy region. The effect of magicity at N = 184 and N = 202 were confirmed from the plot of log{sub 10}T{sub 1/2} versus neutron number of the daughter nuclei for the emission of different clusters. We hope that the systematic and detailed study of all the possible decay modes of {sup 256-339}Ds using various theoretical models will be helpful in the experimental identification of the isotopes of the element in the future. (orig.)

  10. On-line mass separator of superheavy atoms

    International Nuclear Information System (INIS)

    Oganesyan, Yu.Ts.

    2002-01-01

    The concept is presented of an on-line Mass Analyzer of SuperHeavy Atoms (MASHA) dedicated to the separation and determination of the mass and decay properties of new elements and isotopes produced in heavy-ion induced reactions. The new nuclides with half-lives T 1/2 ≥ 1 s are transported to an ECR-source working at a frequency of 2.45 GHz and are separated by mass with a mass resolution of M/ΔM ∼ 1500. In the focal plane of the magnetic analyzer a front strip detector surrounded by side detectors will be placed to determine the mass according to the signals from the detected α-particles or fission fragments with efficiency of about 90 %. In comparison to other existing in-flight recoil separators, the present setup will be characterized by higher efficiency and high selectivity relative to background reaction products. The setup MASHA may be used also in the investigation of nuclear reactions of different type induced by stable and radioactive beams

  11. On-Line Mass Separator of Superheavy Atoms

    CERN Document Server

    Oganessian, Yu T

    2002-01-01

    The concept is presented of an on-line Mass Analyzer of SuperHeavy Atoms (MASHA) dedicated to the separation and determination of the mass and decay properties of new elements and isotopes produced in heavy-ion induced reactions. The new nuclides with half-lives T_{1/2}\\ge 1 s are transported to an ECR-source working at a frequency of 2.45 GHz and are separated by mass with a mass resolution of M/\\Delta M\\sim 1500. In the focal plane of the magnetic analyzer a front strip detector surrounded by side detectors will be placed to determine the mass according to the signals from the detected alpha-particles or fission fragments with efficiency of about 90 %. In comparison to other existing in-flight recoil separators, the present setup will be characterized by higher efficiency and high selectivity relative to background reaction products. The setup MASHA may be used also in the investigation of nuclear reactions of different type induced by stable and radioactive beams.

  12. Synthesis and decay process of superheavy nuclei with Z=119-122 via hot-fusion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Ghahramany, N.; Ansari, A. [Shiraz University, Department of Physics and Biruni Observatory, College of Science, Shiraz (Iran, Islamic Republic of)

    2016-09-15

    In this research article attempts have been made to calculate the superheavy-nuclei synthesis characteristics including, the potential energy parameters, fusion probability, fusion and evaporation residue (ER) cross sections as well as, decay properties of compound nucleus and the residue nuclei formation probability for elements with Z=119-122 by using the hot-fusion reactions. It is concluded that, although a selection of double magic projectiles such as {sup 48}Ca with high binding energy, simplifies the calculations significantly due to spherical symmetric shape of the projectile, resulting in high evaporation residue cross section, unfortunately, nuclei with Z > 98 do not exist in quantities sufficient for constructing targets for the hot-fusion reactions. Therefore, practically our selection is fusion reactions with titanium projectile because the mass production of target nuclei for experimental purposes is more feasible. Based upon our findings, it is necessary, for new superheavy-nuclei production with Z > 119, to use neutron-rich projectiles and target nuclei. Finally, the maximal evaporation residue cross sections for the synthesis of superheavy elements with Z=119-122 have been calculated and compared with the previously founded ones in the literature. (orig.)

  13. Procedural Justice Elements of Judicial Legitimacy and their Contemporary Challenges

    Directory of Open Access Journals (Sweden)

    Nina Persak

    2016-09-01

    Full Text Available Low trust in courts has been recorded in many EU countries. According to the procedural justice paradigm, this phenomenon has negative repercussions for judicial legitimacy, since people who (or when they distrust an authority tend also not to perceive this authority as legitimate (which, in turn, has consequences for their compliance and cooperation with this authority and its decisions. Legitimacy of judiciary, objectively conceived, has several elements, some of which are connected to procedural justice concerns. This article focuses on the latter. In the second part, moreover, the article addresses some of the possible challenges to the judicial procedural justice, drawing on sociological and socio-legal observations regarding legal institutions in the late modern world, where, for example, efficiency-oriented goals mix with justice- and other public good-oriented ones, often creating internal pressures that may impact on the legitimacy of the institution in question. Numerosos países de la UE han registrado una baja confianza en los tribunales. Según el paradigma de la justicia procesal, este fenómeno tiene repercusiones negativas para la legitimidad judicial, ya que las personas que (o cuando desconfían de una autoridad, también tienden a no percibir esta autoridad como legítima (lo que, a su vez, tiene consecuencias para su conformidad y cooperación con esta autoridad y sus decisiones. La legitimidad del poder judicial, concebida de forma objetiva, tiene diversos elementos, algunos de los cuales están relacionados con las preocupaciones de la justicia procesual. Este artículo se centra en estos elementos. En la segunda parte, además, el artículo aborda algunos de los posibles desafíos de la justicia de procesal, basándose en observaciones sociológicas y sociojurídicas relacionadas con las instituciones legales en el mundo moderno reciente, donde, por ejemplo, los objetivos orientados a la eficiencia se mezclan con objetivos

  14. French contribution to the super-heavy nuclei discovery

    International Nuclear Information System (INIS)

    Nifenecker, H.; Asghar, M.

    1999-01-01

    The research on super-heavy nuclei is a science in full operation for which the Berkeley physicist give proof of perseverance. The author wonders about the french absence in this domain. He recalls the strategical decisions concerning the research programs of the period and gives outline of the future with the interest of the ECR (Electronic Cyclotron Resonance) sources. (A.L.B.)

  15. Dynamics of light, intermediate, heavy and superheavy nuclear ...

    Indian Academy of Sciences (India)

    2014-05-01

    May 1, 2014 ... Various features related to the dynamics of competing decay modes of nuclear systems are explored by addressing the experimental data of a number of reactions in light, intermediate, heavy and superheavy mass regions. The DCM, being a non-statistical description for the decay of a com- pound nucleus ...

  16. Salam-Weinberg symmetry breaking with superheavy Higgs particles

    International Nuclear Information System (INIS)

    Misra, S.P.

    1986-09-01

    We discuss here the possibility of the breaking of the Salam-Weinberg symmetry by Higgs particles which are superheavy. The symmetry-breaking is associated with a nonzero vacuum expectation value of fermion condensates. This mechanism, if operative in nature, will imply the absence of Higgs particles at the weak scale. (author)

  17. Barrier for cold-fusion production of superheavy elements

    International Nuclear Information System (INIS)

    Ichikawa, Takatoshi; Iwamoto, Akira; Moeller, Peter; Sierk, Arnold J.

    2005-01-01

    We estimate the fusion-barrier height B fu (two-body) for approaching ions in cold-fusion reactions in a model where the projectile deformation and quadrupole zero-point vibrational energy are taken into account. This barrier height is defined as the barrier energy at the target and projectile separation distance where an original oblate deformation of projectile and/or target caused by a repulsive Coulomb force turns into a large prolate deformation caused by the attractive nuclear force as the target and projectile come closer. The instability develops before touching because the attractive short-range nuclear force overcomes the repulsive Coulomb force and the shape-stabilizing effect of shell structure. The shell structure of the doubly magic 208 Pb target is sufficiently strong that its shape remains very close to spherical in all cases studied here. The fusion potential for approaching ions in the two-body channel is calculated in the macroscopic-microscopic model with the quadrupole vibrational zero-point energy obtained in the WKB approximation. We compare our results with data from 10 experimental cold-fusion reactions and with the Bass barriers. Differences and similarities between the Yukawa-plus-exponential model and the Bass model are discussed. We also calculate five-dimensional potential-energy surfaces for the single compound system and show that well-established fission and fusion valleys are both present. For heavy systems, B fu (two-body) becomes lower than the fission barrier just beyond the ground state of the compound system. In the vicinity of this transition, the optimum collision energy for formation of evaporation residues can be expected to depend in a delicate fashion on the interplay among B fu (two-body) , the fusion valley, the fission barrier of the compound system, and the one- and two-neutron separation energies S 1n and S 2n . We discuss these issues in detail and calculate fission-barrier heights. Except for reactions in which the projectile is doubly magic or near doubly magic, the calculated quantities are consistent with the observed optimal energies for evaporation-residue formation

  18. Alpha decay properties of heavy and superheavy elements

    Indian Academy of Sciences (India)

    region which is smoothly connected by a Yukawa plus exponential potential for the region after separation. Then the potential as a function of r (which is the centre of mass distance .... A 789, 142 (2007). [12] I Muntian, S Hofmann, Z Patyk and A Sobiczewski, Acta Phys. Pol. B 32, 691 (2001). [13] D Ackermann, Nucl. Phys.

  19. Nonlinear finite element analyses: advances and challenges in dental applications.

    Science.gov (United States)

    Wakabayashi, N; Ona, M; Suzuki, T; Igarashi, Y

    2008-07-01

    To discuss the development and current status of application of nonlinear finite element method (FEM) in dentistry. The literature was searched for original research articles with keywords such as nonlinear, finite element analysis, and tooth/dental/implant. References were selected manually or searched from the PUBMED and MEDLINE databases through November 2007. The nonlinear problems analyzed in FEM studies were reviewed and categorized into: (A) nonlinear simulations of the periodontal ligament (PDL), (B) plastic and viscoelastic behaviors of dental materials, (C) contact phenomena in tooth-to-tooth contact, (D) contact phenomena within prosthodontic structures, and (E) interfacial mechanics between the tooth and the restoration. The FEM in dentistry recently focused on simulation of realistic intra-oral conditions such as the nonlinear stress-strain relationship in the periodontal tissues and the contact phenomena in teeth, which could hardly be solved by the linear static model. The definition of contact area critically affects the reliability of the contact analyses, especially for implant-abutment complexes. To predict the failure risk of a bonded tooth-restoration interface, it is essential to assess the normal and shear stresses relative to the interface. The inclusion of viscoelasticity and plastic deformation to the program to account for the time-dependent, thermal sensitive, and largely deformable nature of dental materials would enhance its application. Further improvement of the nonlinear FEM solutions should be encouraged to widen the range of applications in dental and oral health science.

  20. Rare Earth Elements - A New Challenge for the World Economy

    Directory of Open Access Journals (Sweden)

    Cristina Bumbac

    2013-01-01

    Full Text Available Rare Earth Elements or Rare Earth Metals (REM are a collection of seventeen chemical elements in the periodic table, namely scandium, yttrium and fifteen lanthanides. The term "rare earth" arises from the rare earth minerals from which they were first isolated. They are uncommon oxide-type minerals (earths found in Gandolinite extracted from one mine in Sweden. The first discovery was made in 1794, but it was only in 1940 that the scientist Frank Spedding developed an ion exchange procedure for separating and purifying the REM. For the next decades, they were hardly used in some "minor" industrial fields. Only after 2000 their importance grew, once the multitude of possibilities to use them was discovered due to technological progress. Now REM are incorporated into almost all modern technological devices: superconductors, magnets, electronic polishers, refining catalysts hybrid car components and military techniques. They are used in small quantities, but due to their extraordinary properties the prices are very high. The main problem is that China dominates this market, with 97% of total global supply. The highest concentration of rare earth metals are in Inner Mongolia in China, Mountain Pass in California U.S.A. and in Mount Weld in Australia. The developed countries are far behind China regarding production and are indeed depending on Chinese exports. Hence, there is a difficult situation on this particular market, with an uncertain future.

  1. Stability of superheavy elements around Z=120 probed by the study of their fission time obtained by the crystal blocking method; Stabilite d'elements superlourds au voisinage de Z=120 testee par l'etude de leurs temps de fission deduits par la methode du blocage cristallin

    Energy Technology Data Exchange (ETDEWEB)

    Laget, M

    2007-10-15

    While the existence of an island of stability beyond Z=110 is theoretically acquired, the location of this island ranges from Z=114 to Z=126 depending on models. In this work, the stability of super-heavy nuclei is probed through the study of their fission time. The chosen experimental method, the crystal blocking method, is sensitive to the presence of possible long time components in the fission time distribution which indicates a fission mechanism occurring after the formation of a compound nucleus. The blocking dips were therefore constituted for the various products of the reaction U{sup 238} + Ni (6.6 MeV/A) {yields} 120, the experimental set-up allowing us to clearly identify and select the reaction mechanisms. The comparison of the blocking dip constituted for quasi-elastic scattering events with the one obtained for the fission fragments of a Z=120, combined with the study of kinematical properties of these fission fragments, give evidences of the existence of very long fission times (> 10{sup -18} s) only compatible with a fusion-fission mechanism implying a non vanishing fission barrier height for Z=120. The second part outlines microscopic calculations of fission barrier heights, carried out in the framework of the finite temperature of the Hartree-Fock-Bogoliubov (HFB) theory. Because of the progressive vanishing of the pairing correlation with T, which happens differently at the ground state and at the top of the barrier, B{sub f} first grows until T {approx_equal} 0.8 MeV before dropping with T owing to shell-effects damping with temperature. (author)

  2. IR laser enrichment of light elements isotopes - challenges and prospects

    International Nuclear Information System (INIS)

    Parthasarathy, V.

    2002-01-01

    Full text: Infra-red multiple photon dissociation (IR MPD) of poly-atomic molecules has made considerable progress since its discovery in the early seventies. Since the process was found to be isotopically selective; the possibility of laser isotope separation (LIS) created a lot of initial excitement. While the early investigations were concerned with the fundamental dynamics and potential applications of the phenomenon, serious efforts for the isotope enrichment process have been made only during the last decade. These efforts focussed on aspects to improve both the enrichment factor and throughput in various systems. Many research groups have achieved a good measure of success for scaling up the process for various light elements like carbon, oxygen, silicon and sulphur whose isotopes are quite important in medicine and technology. Significant results have been reported especially for the separation of carbon isotopes wherein macroscopic operating scales have been already realised. This talk will give-a summary of our work carried out at BARC and highlight the current efforts for scaling up the process for carbon isotopes enrichment. This would include the design aspects of a large photochemical reactor with multi-pass, refocusing optics for efficient photon utilization. It will also cover the development of a cryogenic distillation set up and a preparative gas chromatograph for a large scale separation and collection of the isotopically enriched photoproduct in the post irradiation stage. Based on the experience gained and infra structure developed, plans are afoot to separate oxygen and sulphur isotopes using a similar approach

  3. Challenges in nucleosynthesis of trans-iron elements

    International Nuclear Information System (INIS)

    Rauscher, T.

    2014-01-01

    Nucleosynthesis beyond Fe poses additional challenges not encountered when studying astrophysical processes involving light nuclei. Astrophysical sites and conditions are not well known for some of the processes involved. On the nuclear physics side, different approaches are required, both in theory and experiment. The main differences and most important considerations are presented for a selection of nucleosynthesis processes and reactions, specifically the s-, r-, γ-, and νp-processes. Among the discussed issues are uncertainties in sites and production conditions, the difference between laboratory and stellar rates, reaction mechanisms, important transitions, thermal population of excited states, and uncertainty estimates for stellar rates. The utility and limitations of indirect experimental approaches are also addressed. The presentation should not be viewed as confining the discussed problems to the specific processes. The intention is to generally introduce the concepts and possible pitfalls along with some examples. Similar problems may apply to further astrophysical processes involving nuclei from the Fe region upward and/or at high plasma temperatures. The framework and strategies presented here are intended to aid the conception of future experimental and theoretical approaches

  4. Fission properties of superheavy nuclei for r -process calculations

    Science.gov (United States)

    Giuliani, Samuel A.; Martínez-Pinedo, Gabriel; Robledo, Luis M.

    2018-03-01

    We computed a new set of static fission properties suited for r -process calculations. The potential energy surfaces and collective inertias of 3640 nuclei in the superheavy region are obtained from self-consistent mean-field calculations using the Barcelona-Catania-Paris-Madrid energy density functional. The fission path is computed as a function of the quadrupole moment by minimizing the potential energy and exploring octupole and hexadecapole deformations. The spontaneous fission lifetimes are evaluated employing different schemes for the collective inertias and vibrational energy corrections. This allows us to explore the sensitivity of the lifetimes to those quantities together with the collective ground-state energy along the superheavy landscape. We computed neutron-induced stellar reaction rates relevant for r -process nucleosynthesis using the Hauser-Feshbach statistical approach and study the impact of collective inertias. The competition between different reaction channels including neutron-induced rates, spontaneous fission, and α decay is discussed for typical r -process conditions.

  5. Fission dynamics of superheavy nuclei formed in uranium induced reactions

    International Nuclear Information System (INIS)

    Gurjit Kaur; Sandhu, Kirandeep; Sharma, Manoj K.

    2017-01-01

    The compound nuclear system follows symmetric fission if the competing processes such as quasi-elastic, deep inelastic, quasi-fission etc are absent. The contribution of quasi fission events towards the fusion-fission mechanism depends on the entrance channel asymmetry of reaction partners, deformations and orientations of colliding nuclei beside the dependence on energy and angular momentum. Usually the 209 Bi and 208 Pb targets are opted for the production of superheavy nuclei with Z CN =104-113. The nuclei in same mass/charge range can also be synthesized using actinide targets + light projectiles (i.e. asymmetric reaction partners) via hot fusion interactions. These actinide targets are prolate deformed which prefer the compact configurations at above barrier energies, indicating the occurrence of symmetric fission events. Here an attempt is made to address the dynamics of light superheavy system (Z CN =104-106), formed via hot fusion interactions involving actinide targets

  6. Fusion-fission of superheavy nuclei at low excitation energies

    International Nuclear Information System (INIS)

    Itkis, M.G.; Oganesyan, Yu.Ts.; Kozulin, E.M.

    2000-01-01

    The process of fusion-fission of superheavy nuclei with Z = 102 -122 formed in the reactions with 22 Ne, 26 Mg, 48 Ca, 58 Fe and 86 Kr ions at energies near and below the Coulomb barrier has been studied. The experiments were carried out at the U-400 accelerator of the Flerov Laboratory of Nuclear Reactions (JINR) using a time-of-flight spectrometer of fission fragments CORSET and a neutron multi-detector DEMON. As a result of the experiments, mass and energy distributions of fission fragments, fission and quasi-fission cross sections, multiplicities of neutrons and gamma-rays and their dependence on the mechanism of formation and decay of compound superheavy systems have been studied

  7. Era of superheavy-particle dominance and big bang nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Polnarev, A.G.; Khlopov, M.Y.

    1982-01-01

    The observed primordial He/sup 4/ abundance imposes astrophysical constraints on the possible departures from radiation dominance in the big bang universe during the neutron hardening era (at epoch t roughly-equal1 sec). Limits are obtained which, along with the data on the spectrum of the cosmic background radiation, practically rule out any stages of superheavy stable-particle dominance in the era 1< or approx. =t<10/sup 10/ sec, thereby setting restrictions on current elementary-particle theories.

  8. Structural and decay properties of Z = 132, 138 superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Rather, Asloob A.; Ikram, M.; Usmani, A.A. [Aligarh Muslim University, Department of Physics, Aligarh (India); Kumar, Bharat; Patra, S.K. [Institute of Physics, Bhubaneswar (India); Homi Bhabha National Institute, Mumbai, Anushakti Nagar (India)

    2016-12-15

    In this paper, we analyze the structural properties of Z = 132 and Z = 138 superheavy nuclei within the ambit of axially deformed relativistic mean-field framework with NL3* parametrization and calculate the total binding energies, radii, quadrupole deformation parameter, separation energies, density distributions. We also investigate the phenomenon of shape coexistence by performing the calculations for prolate, oblate and spherical configurations. For clear presentation of nucleon distributions, the two-dimensional contour representation of individual nucleon density and total matter density has been made. Further, a competition between possible decay modes such as α-decay, β-decay and spontaneous fission of the isotopic chain of superheavy nuclei with Z = 132 within the range 312 ≤ A ≤ 392 and 318 ≤ A ≤ 398 for Z = 138 is systematically analyzed within self-consistent relativistic mean-field model. From our analysis, we inferred that the α-decay and spontaneous fission are the principal modes of decay in majority of the isotopes of superheavy nuclei under investigation apart from β-decay as dominant mode of decay in {sup 318-322}138 isotopes. (orig.)

  9. New elements. [Translated from Vestnik Akademii Nauk SSSR, 6 (1974)

    Energy Technology Data Exchange (ETDEWEB)

    Flerov, G

    1976-04-01

    The history is briefly described of the investigation of superheavy elements at the Joint Institute for Nuclear Research at Dubna. The significance of the investigation is assessed from the point of view of the nuclear structure study and major problems encountered in experimental efforts are indicated. Current experimental methods aiming at the discovery or the production of superheavy nuclei with Z approximately 114 are listed.

  10. Status and prospect of super-heavy nuclei research at IMP

    International Nuclear Information System (INIS)

    Xu Hushan; Sun Zhiyu; Zhan Wenlong; Zhou Xiaohong; Huang Wenxue; Zhang Hongbin; Gan Zaiguo; Li Junqing; Ma Xinwen; Qin Zhi; Xiao Guoqing; Guo Zhongyan; Li Zhihui; Zhang Yuhu; Jin Genming; Huang Tianheng; Hu Zhengguo; Zhang Xueheng; Zheng Chuan; Chinese Academy of Sciences, Beijing

    2006-01-01

    The history and the international status of the super-heavy nuclei synthesis are briefly described. The related research work carried out at the Institute of Modern Physics (IMP) has been reviewed. The prospect of the super-heavy nuclei research at IMP has been introduced. (authors)

  11. On the problem of synthesis of superheavy nuclei. A short historical review on first theoretical predictions

    International Nuclear Information System (INIS)

    Kalinkin, B.N.; Gareev, F.A.

    1999-01-01

    It is shown that it is just Dubna that possesses the priority both in the recent synthesis of a superheavy nucleus with charge Z=114 (Flerov Laboratory of Nuclear Reactions, JINR) and in its theoretical prediction (Bogolyubov Laboratory of Theoretical Physics, JINR) made 33 years ago. Possible sizes of the 'island of stability' of superheavy nuclei are discussed

  12. Superheavy Nuclei in the Quark-Meson-Coupling Model

    Directory of Open Access Journals (Sweden)

    Stone Jirina

    2017-01-01

    Full Text Available We present a selection of the first results obtained in a comprehensive calculation of ground state properties of even-even superheavy nuclei in the region of 96 < Z < 136 and 118 < N < 320 from the Quark-Meson-Coupling model (QMC. Ground state binding energies, the neutron and proton number dependence of quadrupole deformations and Qα values are reported for even-even nuclei with 100 < Z < 136 and compared with available experimental data and predictions of macro-microscopic models. Predictions of properties of nuclei, including Qα values, relevant for planning future experiments are presented.

  13. Chemical identification and properties of element 112

    Czech Academy of Sciences Publication Activity Database

    Yakushev, AB.; Zvára, Ivo; Oganessian, YT.; Belozerov, AV.; Dmitriev, S. N.; Eichler, B.; Hubener, S.; Sokol, EA.; Turler, A.; Yeremin, AV.; Buklanov, GV.; Chelnokov, ML.; Chepigin, VI.; Gorshkov, VA.; Gulyaev, AV.; Lebedev, VY.; Malyshev, ON.; Popeko, AG.; Soverna, S.; Szeglowski, Z.; Timokhin, SN.; Tretyakova, SP.; Vasko, VM.; Itkis, MG.

    2003-01-01

    Roč. 91, č. 8 (2003), s. 433-439 ISSN 0033-8230 Institutional research plan: CEZ:AV0Z1048901 Keywords : element 112 * superheavy elements * transactinoids Subject RIV: CH - Nuclear ; Quantum Chemistry Impact factor: 0.940, year: 2003

  14. Superheavy nuclei in the relativistic mean-field theory

    International Nuclear Information System (INIS)

    Lalazissis, G.A.; Ring, P.; Gambhir, Y.K.

    1996-01-01

    We have carried out a study of superheavy nuclei in the framework of the relativistic mean-field theory. Relativistic Hartree-Bogoliubov (RHB) calculations have been performed for nuclei with large proton and neutron numbers. A finite-range pairing force of Gogny type has been used in the RHB calculations. The ground-state properties of very heavy nuclei with atomic numbers Z=100-114 and neutron numbers N=154-190 have been obtained. The results show that in addition to N=184 the neutron numbers N=160 and N=166 exhibit an extra stability as compared to their neighbors. For the case of protons the atomic number Z=106 is shown to demonstrate a closed-shell behavior in the region of well deformed nuclei about N=160. The proton number Z=114 also indicates a shell closure. Indications for a doubly magic character at Z=106 and N=160 are observed. Implications of shell closures on a possible synthesis of superheavy nuclei are discussed. (orig.)

  15. Superheavy nuclei and quasi-atoms produced in collisions of transuranium ions

    International Nuclear Information System (INIS)

    Zagrebaev, V.; Oganessian, Y.; Itkis, M.; Greiner, W.

    2005-01-01

    For near-barrier collisions of heavy nuclei it is very important to perform a combined (unified) analysis of all strongly coupled channels: deep-inelastic scattering, quasi-fission, fusion and regular fission. This ambitious goal has now become possible within our new approach. The standard (most important) degrees of freedom are used and a unified potential energy surface is derived determining evolution of the nuclear system in all the channels. This potential has also appropriate values of the Coulomb barriers in the entrance channel and proper values of the fission barriers in the exit one. A unified set of dynamic Langevin type equations is proposed for the simultaneous description of DI and fusion-fission processes including nucleon transfer at all reaction stages. For the first time, the whole evolution of the heavy nuclear system can be traced starting from the approaching stage and ending in DI, QF, and/or fusion-fission channels. The calculated mass, charge, energy and angular distributions of the reaction products agree well with available experimental data. Satisfactory agreement of the first calculations with experiments gives us hope not only to obtain rather accurate predictions for the probabilities of superheavy element formation in near-barrier fusion reactions but also to clarify much better than before the mechanisms of quasi-fission and fusion-fission processes. Also the determination of such fundamental characteristics of nuclear dynamics as the nuclear viscosity and the nucleon transfer rate is now possible. Low energy collisions of very heavy nuclei ( 238 U+ 238 U, 232 Th+ 250 Cf and 238 U + 248 Cm) have been studied within the proposed dynamical model. The multidimensional potential energy surfaces of such systems are rather complicated due to the shell effects and dynamic deformations, even if there is no distinct potential pocket. We found that at low near barrier collision energies these very heavy nuclei, after touching their surfaces

  16. Recent developments for high-precision mass measurements of the heaviest elements at SHIPTRAP

    International Nuclear Information System (INIS)

    Minaya Ramirez, E.; Ackermann, D.; Blaum, K.; Block, M.; Droese, C.; Düllmann, Ch. E.; Eibach, M.; Eliseev, S.; Haettner, E.; Herfurth, F.; Heßberger, F.P.

    2013-01-01

    Highlights: • Direct high-precision mass measurements of No and Lr isotopes performed. • High-precision mass measurements with a count rate of 1 ion/hour demonstrated. • The results provide anchor points for a large region connected by alpha-decay chains. • The binding energies determine the strength of the deformed shell closure N = 152. • Technical developments and new techniques will pave the way towards heavier elements. -- Abstract: Atomic nuclei far from stability continue to challenge our understanding. For example, theoretical models have predicted an “island of stability” in the region of the superheavy elements due to the closure of spherical proton and neutron shells. Depending on the model, these are expected at Z = 114, 120 or even 126 and N = 172 or 184. Valuable information on the road to the island of stability is derived from high-precision mass measurements, which give direct access to binding energies of short-lived trans-uranium nuclei. Recently, direct mass measurements at SHIPTRAP have been extended to nobelium and lawrencium isotopes around the deformed shell gap N = 152. In order to further extend mass measurements to the region of superheavy elements, new technical developments are required to increase the performance of our setup. The sensitivity will increase through the implementation of a new detection method, where observation of one single ion is sufficient. Together with the use of a more efficient gas stopping cell, this will us allow to significantly enhance the overall efficiency of SHIPTRAP

  17. The synthesis of superheavy nuclei in the 48Ca + 244Pu reaction

    International Nuclear Information System (INIS)

    Oganesyan, Yu.Ts.; Utenkov, V.K.; Lobanov, Yu.V.

    1999-01-01

    In the bombardment of a 244 Pu target with 48 Ca ions, we observed a decay sequence consisting of an implanted heavy atom, three subsequent α-decays, and a spontaneous fission, all correlated in time and position. The measured α-energies and corresponding time intervals were: E α = 9.71 MeV (Δt = 30.4 s), 8.67 MeV (Δt = 15.4 min) and 8.83 MeV (Δt = 1.6 min); for the spontaneous fission (Δt = 16.5 min) the total deposited energy was approximately 190 MeV. The large alpha-particle energies together with the long decay times and spontaneous fission terminating the chain offer evidence of the decay of nuclei with high atomic numbers. This decay chain is a good candidate for originating from the α-decay of the parent nucleus 289 114, produced in the 3n-evaporation channel with a cross section of about 1 pb. The significant increase in the lifetimes of the new Z = 112 and 110 daughters of the Z = 114 nuclide (by a factor of ∼ 10 6 ) with respect to the known heaviest isotopes of elements 112 and 110 can be considered as a direct proof of the existence of the 'island of stability' of superheavy elements

  18. Seal coat damage evaluation due to superheavy load moves based on a mechanistic-empirical approach.

    Science.gov (United States)

    2010-03-01

    The number of superheavy load (SHL) moves has increased drastically within the past 5 years in : Texas. Along with the increasing SHL moves, the Texas Department of Transportation (TxDOT) has : become increasingly aware of the rising concerns associa...

  19. New semi-empirical formula for α-decay half-lives of the heavy and superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Manjunatha, H.C. [Government College for Women, Department of Physics, Kolar, Karnataka (India); Sridhar, K.N. [Government First Grade College, Department of Physics, Kolar, Karnataka (India)

    2017-07-15

    We have succesfully formulated the semi-empirical formula for α-decay half-lives of heavy and superheavy nuclei for different isotopes of the wide atomic-number range 94 < Z < 136. We have considered 2627 isotopes of heavy and superheavy nuclei for the fitting. The value produced by the present formula is compared with that of experiments and other eleven models, i.e. ImSahu, Sahu, Royer10, VS2, UNIV2, SemFIS2, WKB. Sahu16, Densov, VSS and Royer formula. This formula is exclusively for heavy and superheavy nuclei. α-decay is one of the dominant decay mode of superheavy nucleus. By identifying the α-decay mode superheavy nuclei can be detected. This formula helps in predicting the α-decay chains of superheavy nuclei. (orig.)

  20. How far are we on the way to the superheavy nuclei?

    International Nuclear Information System (INIS)

    Muenzenberg, G.

    1989-10-01

    The discovery of the elements 107, 108, and 109 in a region of dominating shell stabilization is the most important step on the way to the superheavy nuclei in recent years. These experiments leading to the presently upper end of the periodic table were possible with the velocity filter SHIP to separate the heavy nuclei produced in complete fusion reactions of heavy ions. The identification of the unknown nuclei was established by α-α mother-daughter correlation of the nuclei decaying after the implantation into position sensitive surface-barrier detectors. With this method it is possible to identify even single nuclei of unknown isotopes unambiguously. The limits of sensitivity are production cross-sections of a few picobarns and about 2 μs of nuclear lifetime. With this method the elements 107, 108, and 109 were observed for the first time by their α-decay and identified unambiguously. For element 107 the isotopes with masses 261 and 262, for the element 108 the isotopes with masses 264 and 265, and for element 109 the isotope with mass 266 were found. The halflives range from 0.1 ms to 0.1 s. The highly fissile transactinide nuclei were produced in cold fusion of heavy ions using 207,208 Pb and 209 Bi targets, respectively, and 50 Ti, 54 Cr, or 58 Fe beams. The evaluation of the excitation functions for the production of very heavy evaporation residues shows a strong decrease above 25 MeV excitation energy caused by a destruction of the groundstate shell effects at high excitation energies. The strong competition of barrier transmission and survival probability results in rather narrow excitation functions and small production cross sections. The maximum cross section is observed close to the Coulomb barrier and corresponding to projectile energies near 5 MeV/u. (orig.) [de

  1. α decay chains in 271-294115 superheavy nuclei

    International Nuclear Information System (INIS)

    Santhosh, K. P.; Priyanka, B.; Joseph, Jayesh George; Sahadevan, Sabina

    2011-01-01

    α decay of 271-294 115 superheavy nuclei is studied using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The predicted α half-lives of 287 115 and 288 115 nuclei and their decay products are in good agreement with experimental values. Comparison of α and spontaneous fission half-lives predicts four-α chains and three-α chains, respectively, from 287 115 and 288 115 nuclei and are in agreement with experimental observation. Our study predicts two-α chains from 273,274,289 115, three-α chains from 275 115, and four-α chains consistently from 284,285,286 115 nuclei. These observations will be useful for further experimental investigation in this region.

  2. Alpha Decay of Even-Even Superheavy Nuclei

    International Nuclear Information System (INIS)

    Oudih, M.R.; Hamza, Y.; Fellah, M.; Allal, N.H.; Fellah, M.; Allal, N.H.

    2011-01-01

    Alpha decay properties of even-even superheavy nuclei with 112.Z.120 have been investigated using the Hartree-Fock-Bogoliubov approach. The method is based on the SkP Skyrme interaction and the Lipkin-Nogami prescription for treating the pairing correlations. The alpha decay energies are extracted from the binding energies and then used for the calculation of the decay half-lives using a formula similar to that of Viola-Seaborg. The parameters of the formula were obtained through a least square fit to even-even heavy nuclei taken from the tables of Audi- Wapstra and some more recent references. The results are compared with other theoretical evaluations.

  3. The transuranium elements: From neptunium and plutonium to element 112

    International Nuclear Information System (INIS)

    Hoffman, D.C.

    1996-01-01

    Beginning in the 1930's, both chemists and physicists became interested in synthesizing new artificial elements. The first transuranium element, Np, was synthesized in 1940. Over the past six decades, 20 transuranium elements have been produced. A review of the synthesis is given. The procedure of naming the heavy elements is also discussed. It appears feasible to produce elements 113 and 114. With the Berkeley Gas-filled Separator, it should be possible to reach the superheavy elements in the region of the spherical Z=114 shell, but with fewer neutrons than the N=184 spherical shell. 57 refs, 6 figs

  4. First attempt to chemically identify element 112

    Czech Academy of Sciences Publication Activity Database

    Yakushev, AB.; Buklanov, GV.; Chelnokov, ML.; Chepigin, VI.; Dmitriev, S. N.; Gorshkov, VA.; Hubener, S.; Malyshev, ON.; Oganessian, YT.; Popeko, AG.; Sokol, EA.; Timokhin, SN.; Turler, A.; Vasko, VM.; Yeremin, AV.; Zvára, Ivo

    2001-01-01

    Roč. 89, 11/12 (2001), s. 743-745 ISSN 0033-8230 Institutional research plan: CEZ:AV0Z1048901 Keywords : superheavy elements * actionoid * transactinoids Subject RIV: CH - Nuclear ; Quantum Chemistry Impact factor: 0.660, year: 2001

  5. Discovery of element 112

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, S. [GSI, Darmstadt (Germany)

    1996-12-31

    The new elements 110, 111, and 112 were synthesized and unambiguously identified in experiments at SHIP. Due to strong shell effects the dominant decay mode is not fission, but emission of alpha particles. Theoretical investigations predict that maximum shell effects should exist in nuclei near proton number 114 and neutron number 184. Measurements give hope that isotopes of element 114 close to the island of spherical Superheavy Elements could be produced by fusion reactions using {sup 118}Pb as target. systematic studies of the reaction cross-sections indicate that transfer of nucleons is the important process to initiate the fusion.

  6. CHARGE SPECTRUM OF HEAVY AND SUPERHEAVY COMPONENTS OF GALACTIC COSMIC RAYS: RESULTS OF THE OLIMPIYA EXPERIMENT

    Energy Technology Data Exchange (ETDEWEB)

    Alexeev, Victor; Kalinina, Galina; Pavlova, Tatyana, E-mail: aval37@mail.ru, E-mail: gakalin@mail.ru, E-mail: pavlova4tat@mail.ru [Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, 19 Kosygin Str., Moscow 119991 (Russian Federation); and others

    2016-10-01

    The aim of the OLIMPIYA experiment is to search for and identify traces of heavy and superheavy nuclei of galactic cosmic rays (GCR) in olivine crystals from stony–iron meteorites serving as nuclear track detectors. The method is based on layer-by-layer grinding and etching of particle tracks in these crystals. Unlike the techniques of other authors, this annealing-free method uses two parameters: the etching rate along the track ( V {sub etch}) and the total track length ( L ), to identify charge Z of a projectile. A series of irradiations with different swift heavy ions at the accelerator facilities of GSI (Darmstadt) and IMP (Lanzhou) were performed in order to determine and calibrate the dependence of projectile charge on V {sub etch} and L . To date, one of the most essential results of the experiment is the obtained charge spectrum of GCR nuclei within the range of Z > 40, based on about 11.6 thousand processed tracks. As the result of data processing, 384 nuclei with charges Z ≥ 75 have been identified, including 10 nuclei identified as actinides (90 < Z < 103). Three tracks were identified to be produced by nuclei with charges 113 < Z < 129. Such nuclei may be part of the Island of Stability of transfermium elements.

  7. Spectroscopy of very heavy nuclei with a view to study super-heavy nuclei

    International Nuclear Information System (INIS)

    Khalfallah, F.

    2007-08-01

    Within the recent years, the spectroscopic study of single particle orbitals of very heavy elements (VHE) has become possible with the development of increasingly efficient experimental setups. This allows us, through nuclear deformation, to access with these deformed nuclei to orbitals situated around the Fermi level in the spherical superheavy elements (SHE) and learn more about the nuclear structure of these nuclei. The aim of this work is the spectroscopic studies of heavy and very heavy elements. Because of the experimental difficulties associated with the fusion reactions in the VHE region, a detailed optimization studies is essential. Simulation of energy loss and angular straggling of these nuclei due to the interaction in the target and to neutron's evaporation was carried out and allowed us to optimize the angular acceptance of the separators according to the target thickness. An extensive survey and exploration in the VHE region was also conducted on the basis of cross section's systematics in the literature and simulations carried out using the statistical code Hivap. In this framework, the possible extension of the range of validity of a set of Hivap parameters was investigated. This work has enabled us to prepare a list of experiments of interest for the production of very heavy nuclei. In this thesis, our work was concentrated on the spectroscopy of the nuclei No 256 et Rf 256 for which two experimental proposals were accepted. The octupole deformations predicted in the actinides region is studied in another part of this thesis, a part witch is dedicated to the gamma spectroscopy of Pa 223 . The data from a new experiment carried out using the Jurogam-Ritu-Great setup are analysed and compared to previous results. They confirm the octupole deformed shape in this nucleus. (author)

  8. Detection and quantification of proteins and cells by use of elemental mass spectrometry: progress and challenges.

    Science.gov (United States)

    Yan, Xiaowen; Yang, Limin; Wang, Qiuquan

    2013-07-01

    Much progress has been made in identification of the proteins in proteomes, and quantification of these proteins has attracted much interest. In addition to popular tandem mass spectrometric methods based on soft ionization, inductively coupled plasma mass spectrometry (ICPMS), a typical example of mass spectrometry based on hard ionization, usually used for analysis of elements, has unique advantages in absolute quantification of proteins by determination of an element with a definite stoichiometry in a protein or attached to the protein. In this Trends article, we briefly describe state-of-the-art ICPMS-based methods for quantification of proteins, emphasizing protein-labeling and element-tagging strategies developed on the basis of chemically selective reactions and/or biospecific interactions. Recent progress from protein to cell quantification by use of ICPMS is also discussed, and the possibilities and challenges of ICPMS-based protein quantification for universal, selective, or targeted quantification of proteins and cells in a biological sample are also discussed critically. We believe ICPMS-based protein quantification will become ever more important in targeted quantitative proteomics and bioanalysis in the near future.

  9. Predictions on the modes of decay of even Z superheavy isotopes within the range 104 ≤ Z ≤ 136

    Science.gov (United States)

    Santhosh, K. P.; Nithya, C.

    2018-01-01

    The decay modes and half lives of all the even Z isotopes of superheavy elements within the range 104 ≤ Z ≤ 136 have been predicted by comparing the alpha decay half-lives with the spontaneous fission half-lives. The Coulomb and proximity potential model for deformed nuclei (CPPMDN) and the shell-effect-dependent formula of Santhosh et al. are used to calculate the alpha half-lives and spontaneous fission half-lives respectively. For theoretical comparison the alpha decay half-lives are also calculated using Coulomb and proximity potential model (CPPM), the Viola-Seaborg-Sobiczewski semi-empirical (VSS) relation, the universal (UNIV) curve of Poenaru et al., the analytical formula of Royer and the universal decay law (UDL) of Qi et al. Another tool used for the evaluation of spontaneous fission half-lives is the semi-empirical formula of Xu et al. The nuclei with alpha decay half-lives less than spontaneous fission half-lives will survive fission and hence decay through alpha emission. The predicted half lives and decay modes are compared with the available experimental results. The one-proton and two-proton separation energies of all the isotopes are calculated to find nuclei which lie beyond the proton drip line. Among 1119 even Z nuclei within the range 104 ≤ Z ≤ 136, 164 nuclei show sequential alpha emission followed by subsequent spontaneous fission. Since the isotopes decay through alpha decay chain and the half-lives are in measurable range, these isotopes are predicted to be synthesized and detected in laboratory via alpha decay. 2 nuclei will decay by alpha decay followed by proton emission, 54 nuclei show full alpha chains, 642 nuclei will decay through spontaneous fission, 166 nuclei exhibit proton decay and 91 isotopes are found to be stable against alpha decay. All the isotopes are tabulated according to their decay modes. The study is intended to enhance further experimental investigations in superheavy region.

  10. Predictions on the modes of decay of odd Z superheavy isotopes within the range 105 ≤ Z ≤ 135

    Science.gov (United States)

    Santhosh, K. P.; Nithya, C.

    2018-05-01

    The decay modes of 1051 odd Z superheavy nuclei within the range 105 ≤ Z ≤ 135, and their daughter nuclei are studied by comparing the alpha decay half-lives with the spontaneous fission half-lives. The alpha decay half-lives are calculated using the Coulomb and proximity potential model for deformed nuclei (CPPMDN) proposed by Santhosh et al. (2011) and the spontaneous fission half-lives are obtained with the shell-effect dependent formula of Santhosh et al. (Santhosh and Nithya, 2016). For a theoretical comparison, the alpha decay half-lives are also computed with the Coulomb and proximity potential model (CPPM), Viola-Seaborg-Sobiczewski semi-empirical relation (VSS), Universal curve of Poenaru et al. (UNIV), the analytical formula of Royer, and the Universal decay law of Qi et al. (UDL). The predicted decay modes and half-lives were compared with the available experimental results. The proton and neutron separation energies are calculated to identify those nuclei, which decay through proton and neutron emission. From the entire study of odd Z superheavy elements, it is seen that among 1051 nuclei, 233 nuclei exhibit proton emission and 18 nuclei exhibit neutron emission. 56 nuclei are stable against alpha decay with negative Q value for the decay. 92 nuclei show alpha decay followed by spontaneous fission and 9 nuclei show alpha decay followed by proton emission. 39 nuclei decay through full alpha chain and 595 nuclei decay through spontaneous fission. We hope that the study will be very useful for the future experimental investigations in this field.

  11. Critical angular momentum dependence of the fission barriers and the stability of superheavy nuclei

    International Nuclear Information System (INIS)

    Magda, M.T.; Sandulescu, A.

    1978-10-01

    Measured complete fusion and evaporation cross section data are used to determine the critical angular momenta for which the fission barriers are vanishing in the region of nuclei with Z = 102 - 116. It is shown that, in order to fit these data, larger values of the critical angular momenta are obtained for superheavy nuclei (Z = 110 - 112) than for heavy ones (Z = 102 - 107), which indicates a relatively higher stability against fission for superheavy nuclei, in agreement with the theoretically predicted island of stability. (author)

  12. Elements beyond uranium

    International Nuclear Information System (INIS)

    Seaborg, G.T.; Loveland, W.D.

    1990-01-01

    This book is the 12th volume in a series on transuranium elements. Varied techniques for production of these elements, the methods used in the identification, and the exquisitely refined microchemical techniques required to deal wth samples sometimes involving only a few atoms are described in detail. The chapter on synthesis of the new elements is liberally laced with reminiscences of the proud progenitors as well as the criteria for the discovery of a new chemical element. The authors lament that the superheavy elements (elements in the region of atomic number 114) still elude detection even though their creation should be possible, and some, at least, should survive long enough to be detected. One chapter in the book is devoted to practical applictions of uranium, and the transuranic elements

  13. Towards the island of superheavy stability - Prompt spectroscopy of 246Fm and 256Rf nuclei

    International Nuclear Information System (INIS)

    Piot, J.

    2010-10-01

    The region of trans-fermium nuclei (Z = 100 to 104) is the last region of the nuclides chart to be accessible to spectroscopic measurements. It therefore provides the ultimate anchor points for nuclear models. This region also lies on the path of the alpha-decay chains of the super-heavy elements. This region represents the limit of today's spectroscopic capabilities. It therefore requires technological developments in order to overcome these limits. My thesis focuses on various aspects of the spectroscopy of trans-fermium nuclei. I took part in the development of the TNT2D digital acquisition cards for germanium detectors. I validated their use on the gamma-ray spectrometer JUROGAM during an in-beam experiment and demonstrated the gain compared to an analogue acquisition system. These tests were part of the developments needed to secure a study of the prompt spectroscopy of 256 Rf. The preparation of this experiment also lead me to work on the development of a 50 Ti beam. For that purpose, I studied and tested the use of titanium organo-metallic compounds compatible with the MIVOC technique. In parallel, I studied the use of metallic and oxide titanium pellets with an inductive oven newly developed at the University of Jyvaeskylae. In addition to these developments, I had the opportunity to study the in-beam prompt spectroscopy of 246 Fm at the University of Jyvaeskylae. The measurements yielded a rotational band built on the ground state of 246 Fm. This band has been observed up to the level 16 + and shows a behaviour quite similar to the neighbouring even-even isotopes, except for the top of the band for which a wider statistics is necessary in order to conclude. (author)

  14. On the Necessity of Using Element No.155 in the Chemical Physical Calculations: Again on the Upper Limit in the Periodic Table of Elements

    Directory of Open Access Journals (Sweden)

    Khazan A.

    2010-10-01

    Full Text Available It is shown how the properties of different elements of the Periodic System of Elements can be obtained using the properties of the theoretically predicted heaviest element No.155 (it draws the upper principal limit of the Table, behind which stable elements cannot exist. It is suggested how the properties of element No.155 can be used in the synthesis of superheavy elements. An analysis of nuclear reactions is also produced on the same basis.

  15. Influence of fragment deformation and orientation on compact configuration of odd-Z superheavy nuclei

    International Nuclear Information System (INIS)

    Gurjit Kaur; Sandhu, Kirandeep; Sharma, Manoj K.

    2016-01-01

    The synthesis of heavy and superheavy nuclei is generally carried out by using hot and cold fusion reaction mechanisms. It has been noticed that, the cold fusion reactions occur at relatively low excitation energies (E*_C_N ∼ 10-20 MeV) whereas, the hot fusion reactions occur at excitation energies of E*_C_N ∼ 30- 50 MeV. The fusion mechanism is quite different in both the processes. In the cold fusion process, the interaction of spherical targets (Pb and Bi) with deformed light mass projectiles occurs. On the other hand, the fusion of deformed actinide targets with spherical "4"8Ca projectile characterize the hot interaction processes. Hence the deformations and orientations of targets and projectiles play extremely important role in the superheavy fusion process. The present analysis is carried out to aggrandize the work of which illustrate the role of deformations and orientations on even superheavy nuclei. Here, we extend this analysis for odd superheavy nuclei. It is relevant to note that the temperature and angular momentum effects are not included in the present analysis

  16. The chemistry of transactinide elements. Experimental achievements and perspectives

    International Nuclear Information System (INIS)

    Schaedel, M.

    2002-01-01

    The chemistry of transactinides and superheavy elements has reached element 108. Preparations are under way to leap to element 112 and beyond. This development, its current status and future perspectives are reviewed from an experimental point of view. The atom-at-a-time situation of transactinide chemistry is briefly outlines. Experimental techniques and important results enlightening the chemical properties of elements 104 through 108 are presented in an exemplary way with emphasis on the aqueous chemistry of the lighter ones. From the results of these experiments it is justified to place these elements in the Periodic Table of the Elements into groups 4 through 8, respectively. However, strongly due to the influence of relativistic effects, it is no longer possible to deduce detailed chemical properties of these superheavy elements from this position. Perspectives for future research programs are given. (author)

  17. Toward the drip lines and the superheavy island of stability with the Super Separator Spectrometer S{sup 3}

    Energy Technology Data Exchange (ETDEWEB)

    Dechery, F.; Boutin, D.; Gall, B.; Le Blanc, F. [Universite de Strasbourg, IPHC, Strasbourg (France); CNRS, UMR7178, Strasbourg (France); Drouart, A.; Authier, M.; Delferriere, O.; Payet, J.; Uriot, D. [CEA-Saclay, Irfu, Gif-sur-Yvette (France); Savajols, H.; Stodel, M.H.; Traykov, E. [GANIL, Caen (France); Nolen, J. [Argonne National Laboratory, Argonne, IL (United States); Amthor, A.M. [Bucknell University, Lewisburg, PA (United States); Hue, A.; Laune, B. [Universite Paris-Sud 11, CNRS/IN2P3, IPNO, Orsay (France); Manikonda, S. [AML Superconductivity and Magnetics, Palm Bay, Florida (United States); Collaboration: S3 Collaboration

    2015-06-15

    The Super Separator Spectrometer S{sup 3} is a major experimental system developed for SPIRAL2. It has been designed for physics experiments with very low cross sections by taking full advantage of the very high intensity stable beams to be produced by LINAG, the superconducting linear accelerator at GANIL. These intensities will open new opportunities in several physics domains using fusion evaporation reactions, principally: super-heavy and very heavy element properties, spectroscopy at and beyond the dripline, and isomer and ground-state properties. The common feature of these experiments is the requirement to separate very rare events from intense backgrounds. S{sup 3} accomplishes this with a large acceptance, a high background rejection efficiency, and a physical mass separation. This article will present the technical specifications and optical constraints needed to achieve these physical goals. The optical layout of the spectrometer will be presented, focusing on technical elements of the target system, the superconducting multipole magnets used to correct high-order optical aberrations, the electric and magnetic dipoles, and the open multipole triplet used for primary beam rejection. The expected system performance will be presented for three experimental cases using 3 specific optical modes of the spectrometer. (orig.)

  18. The mass (charge) spectrum of superheavy nuclei fission fragments: the new perspectives for the theory of nucleosynthesis

    International Nuclear Information System (INIS)

    Maslyuk, V.T.

    2012-01-01

    A new approach to the problem of nucleosynthesis based on assumption of a nuclear matter or superheavy nuclei series fragmentation up to atomic nuclei is proposed. It is shown that studies of the mass (charge) fragments yields (MCFY) after nuclear matter disintegration is possible within proposed statistical theory. The data of MCFY calculation for exotic superheavy nuclei multifragmentation with A=300, 900 and 1200 and arbitrary Z values are demonstrated

  19. Quality management and quality assurance in the manufacture of nuclear fuel elements: new trends and challenges

    International Nuclear Information System (INIS)

    Baur, K.

    1998-01-01

    Modern instruments for quality assurance are applied with increasing success also in the area of fuel element supply. This new philosophy of quality management is characterized by a clear focus on processes and a commitment to continuous quality improvement. How can these new quality concepts, the application of which is desired by the companies operating nuclear power plants, be implemented and find acceptance? Is it possible that error prevention in place of error correction can increase the quality of fuel elements and at the same time reduce costs? What instruments are available to solve problems specific to fuel element technology? Efforts currently under way to answer these questions are described, particularly with regard to cooperation with fuel element suppliers. Within this context, a new guideline 'Quality System for Fuel Elements' has been developed. (orig.) [de

  20. Transfer reaction studies in the region of heavy and superheavy nuclei at SHIP

    Energy Technology Data Exchange (ETDEWEB)

    Heinz, S; Comas, V; Hofmann, S; Ackermann, D; Heredia, J; Hessberger, F P; Khuyagbaatar, J; Kindler, B; Lommel, B; Mann, R, E-mail: s.heinz@gsi.de [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany)

    2011-02-01

    We studied multi-nucleon transfer reactions in the region of heavy and superheavy nuclei. The goal was to investigate these reactions as possibility to create new superheavy neutron-rich isotopes, which cannot be produced in fusion reactions. The experiments have been performed at the velocity filter SHIP at GSI. At SHIP we can detect and identify the heavy, target-like, transfer products. Due to the low background at the focal plane detector and the isotope identification via radioactive decays, the setup allows to reach an upper cross-section limit of 10 pb/sr within one day of beamtime. We investigated the systems {sup 58,64}Ni + {sup 207}Pb and {sup 48}Ca + {sup 248}Cm at beam energies below and up to 20% above the Coulomb barrier. At all energies we observed a massive transfer of protons and neutrons, where transfer products with up to eight neutrons more than the target nucleus could be identified.

  1. On the fate of superheavy magnetic monopoles in a neutron star

    International Nuclear Information System (INIS)

    Kuzmin, V.A.; Rubakov, V.A.; AN SSSR, Moscow. Inst. Yadernykh Issledovanij)

    1983-02-01

    We propose two possible scenarios of the behaviour of superheavy magnetic monopoles in a neutron star, in which the monopole-antimonopole annihilation rate is sufficiently large to prevent the enormous heating of a neutron star due to the monopole induced neutron decays. We find that the galactic monopole flux of order 10 -16 cm -2 s -1 ster -1 can be compatible with the observational limit on the X-ray luminosity of neutron stars. (author)

  2. Super-heavy dark matter – Towards predictive scenarios from inflation

    Energy Technology Data Exchange (ETDEWEB)

    Kannike, Kristjan [National Institute of Chemical Physics and Biophysics, Rävala 10, 10143 Tallinn (Estonia); Racioppi, Antonio, E-mail: antonio.racioppi@kbfi.ee [National Institute of Chemical Physics and Biophysics, Rävala 10, 10143 Tallinn (Estonia); Raidal, Martti [National Institute of Chemical Physics and Biophysics, Rävala 10, 10143 Tallinn (Estonia); Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411 Tartu (Estonia)

    2017-05-15

    A generic prediction of the Coleman–Weinberg inflation is the existence of a heavy particle sector whose interactions with the inflaton, the lightest state in this sector, generate the inflaton potential at loop level. For typical interactions the heavy sector may contain stable states whose relic abundance is generated at the end of inflation by the gravity alone. This general feature, and the absence of any particle physics signal of dark matter so far, motivates us to look for new directions in the dark sector physics, including scenarios in which dark matter is super-heavy. In this article we study the possibility that the dark matter is even heavier than the inflaton, its existence follows from the inflaton dynamics, and its abundance today is naturally determined by the weakness of gravitational interaction. This implies that the super-heavy dark matter scenarios can be tested via the measurements of inflationary parameters and/or the CMB isocurvature perturbations and non-Gaussianities. We explicitly work out details of three Coleman–Weinberg inflation scenarios, study the systematics of super-heavy dark matter production in those cases, and compute which parts of the parameter spaces can be probed by the future CMB measurements.

  3. Microstructure Evolution and Surface Cracking Behavior of Superheavy Forgings during Hot Forging

    Directory of Open Access Journals (Sweden)

    Zhenhua Wang

    2018-01-01

    Full Text Available In recent years, superheavy forgings that are manufactured from 600 t grade ingots have been applied in the latest generation of nuclear power plants to provide good safety. However, component production is pushing the limits of the current free-forging industry. Large initial grain sizes and a low strain rate are the main factors that contribute to the deformation of superheavy forgings during forging. In this study, 18Mn18Cr0.6N steel with a coarse grain structure was selected as a model material. Hot compression and hot tension tests were conducted at a strain rate of 10−4·s−1. The essential nucleation mechanism of the dynamic recrystallization involved low-angle grain boundary formation and subgrain rotation, which was independent of the original high-angle grain boundary bulging and the presence of twins. Twins were formed during the growth of dynamic recrystallization grains. The grain refinement was not obvious at 1150°C. A lowering of the deformation temperature to 1050°C resulted in a fine grain structure; however, the stress increased significantly. Crack-propagation paths included high-angle grain boundaries, twin boundaries, and the insides of grains, in that order. For superheavy forging, the ingot should have a larger height and a smaller diameter.

  4. Super-heavy dark matter – Towards predictive scenarios from inflation

    Directory of Open Access Journals (Sweden)

    Kristjan Kannike

    2017-05-01

    Full Text Available A generic prediction of the Coleman–Weinberg inflation is the existence of a heavy particle sector whose interactions with the inflaton, the lightest state in this sector, generate the inflaton potential at loop level. For typical interactions the heavy sector may contain stable states whose relic abundance is generated at the end of inflation by the gravity alone. This general feature, and the absence of any particle physics signal of dark matter so far, motivates us to look for new directions in the dark sector physics, including scenarios in which dark matter is super-heavy. In this article we study the possibility that the dark matter is even heavier than the inflaton, its existence follows from the inflaton dynamics, and its abundance today is naturally determined by the weakness of gravitational interaction. This implies that the super-heavy dark matter scenarios can be tested via the measurements of inflationary parameters and/or the CMB isocurvature perturbations and non-Gaussianities. We explicitly work out details of three Coleman–Weinberg inflation scenarios, study the systematics of super-heavy dark matter production in those cases, and compute which parts of the parameter spaces can be probed by the future CMB measurements.

  5. Food for Thought: A Critical Overview of Current Practical and Conceptual Challenges in Trace Element Analysis in Natural Waters

    Directory of Open Access Journals (Sweden)

    Montserrat Filella

    2013-07-01

    Full Text Available The practical and conceptual challenges faced by the analysis of trace elements present in natural waters are not merely, as is often thought, an endless race towards lower detection limits or to the development of techniques allowing the determination of any possible chemical species formed by all chemical elements. Rather, as discussed in this paper, they include the development of (i robust, cheap, and reliable methods that could also be used by laypeople (the experience gained in the development of field kits for As is discussed as an example from which similar developments for other elements may be drawn; (ii more environmentally-friendly methods (the current guiding criteria probably being too simplistic; and (iii methods making it possible to follow diel concentration changes and sharp concentration variations caused by the probable increase of heavy rainfall events. This paper also claims that neither the measurement of total concentrations (reliable methods are lacking for many elements of the periodic table of trace elements, as illustrated through the cases of Bi, Te, and Sb, nor chemical speciation analysis, are as mature as often thought. In particular, chemical speciation studies demand the development of a better, comprehensive conceptual framework. A trial is carried out to lay the basis of such a framework.

  6. Development of a novel heavy element chemistry apparatus using the RIKEN gas-field recoil separator as a pre-separator

    International Nuclear Information System (INIS)

    Haba, H.; Morita, K.; Enomoto, S.; Morimoto, K.; Kaji, D.; Nagame, Yuichiro

    2004-01-01

    A new system was developed, that supplied the super-heavy element separated physically as the former steps to the chemical analysis devices such as a gas or liquid chromatographs. The gas jet transportation device was newly set up on the edge of existing accelerator research facilities in the Institute of Physical and Chemical Research linac building (GARIS). To conduct the chemical separation experiment of a super-heavy element of 112 in future a radioactive isotope of mercury of light homology elements was manufactured with a gas jet uniting type online multi-tracer manufacturing device. The adsorption chromatograph experiment to the gold was performed using this system. (H. Katsuta)

  7. Migration of components from cork stoppers to food: challenges in determining inorganic elements in food simulants.

    Science.gov (United States)

    Corona, T; Iglesias, M; Anticó, E

    2014-06-18

    The inorganic elements potentially migrating from cork to a food simulant [a hydroalcoholic solution containing 12 and 20% (v/v) ethanol] have been determined by means of inductively coupled plasma (ICP) with atomic emission and mass spectrometric detection. The experimental instrumental conditions were evaluated in depth, taking into account spectroscopic and nonspectroscopic interference caused by the presence of ethanol and other components in the sample. We report concentrations ranging from 4 μg kg(-1) for Cd to 28000 μg kg(-1) for Al in the food simulant (concentrations given in kilograms of cork). The values found for Ba, Mn, Fe, Cu, and Zn have been compared with the guideline values stated in EU Regulation 10/2011. In all cases, cork met the general safety criteria applicable to food contact material. Finally, we have proposed water as an alternative to the hydroalcoholic solution to simplify quantification of the tested elements using ICP techniques.

  8. On the synthesis of new elements

    International Nuclear Information System (INIS)

    Hofmann, S.

    2003-01-01

    The nuclear shell model predicts that the next doubly magic shell-closure beyond 208 Pb is at a proton number between Z=114 and 126 and at a neutron number N=172 or 184. The outstanding aim of experimental investigations is the exploration of this region of spherical 'Superheavy Elements'. This article describes the experiments that were performed recently at the GSI SHIP. They resulted in an unambiguous identification of elements 110 to 112. They were negative so far in searching for elements 113, 116, and 118. The measured decay data are compared with theoretical predictions. Some aspects concerning the reaction mechanism are also presented. (orig.)

  9. Observation of superheavy primary cosmic ray nuclei with solid state track detectors and x-ray films

    International Nuclear Information System (INIS)

    Doke, Tadayoshi; Hayashi, Takayoshi; Ito, Kensai; Yanagimachi, Tomoki; Kobayashi, Shigeru.

    1977-01-01

    The measurements of energy spectra and the nuclear charge distribution of superheavy nuclei heavier than iron in primary cosmic ray can provide information on the origin, propagation and life time of the cosmic ray. Since incident particles are in the region of relativistic velocity (the low energy cosmic ray below the cutoff energy is forbidden from entering), the charges of cosmic ray nuclei can be determined without knowing the energy of particles. The balloon-borne solid state track detector and plastic and X-ray films were employed for the detection of superheavy cosmic ray, and the five events were detected with the cellulose nitrate film. The flux of superheavy nuclei is predicted from the present analysis. (Yoshimori, M.)

  10. Challenges of biological sample preparation for SIMS imaging of elements and molecules at subcellular resolution

    Science.gov (United States)

    Chandra, Subhash

    2008-12-01

    Secondary ion mass spectrometry (SIMS) based imaging techniques capable of subcellular resolution characterization of elements and molecules are becoming valuable tools in many areas of biology and medicine. Due to high vacuum requirements of SIMS, the live cells cannot be analyzed directly in the instrument. The sample preparation, therefore, plays a critical role in preserving the native chemical composition for SIMS analysis. This work focuses on the evaluation of frozen-hydrated and frozen freeze-dried sample preparations for SIMS studies of cultured cells with a CAMECA IMS-3f dynamic SIMS ion microscope instrument capable of producing SIMS images with a spatial resolution of 500 nm. The sandwich freeze-fracture method was used for fracturing the cells. The complimentary fracture planes in the plasma membrane were characterized by field-emission secondary electron microscopy (FESEM) in the frozen-hydrated state. The cells fractured at the dorsal surface were used for SIMS analysis. The frozen-hydrated SIMS analysis of individual cells under dynamic primary ion beam (O 2+) revealed local secondary ion signal enhancements correlated with the water image signals of 19(H 3O) +. A preferential removal of water from the frozen cell matrix in the Z-axis was also observed. These complications render the frozen-hydrated sample type less desirable for subcellular dynamic SIMS studies. The freeze-drying of frozen-hydrated cells, either inside the instrument or externally in a freeze-drier, allowed SIMS imaging of subcellular chemical composition. Morphological evaluations of fractured freeze-dried cells with SEM and confocal laser scanning microscopy (CLSM) revealed well-preserved mitochondria, Golgi apparatus, and stress fibers. SIMS analysis of fractured freeze-dried cells revealed well-preserved chemical composition of even the most highly diffusible ions like K + and Na + in physiologically relevant concentrations. The high K-low Na signature in individual cells

  11. Challenges of biological sample preparation for SIMS imaging of elements and molecules at subcellular resolution

    International Nuclear Information System (INIS)

    Chandra, Subhash

    2008-01-01

    Secondary ion mass spectrometry (SIMS) based imaging techniques capable of subcellular resolution characterization of elements and molecules are becoming valuable tools in many areas of biology and medicine. Due to high vacuum requirements of SIMS, the live cells cannot be analyzed directly in the instrument. The sample preparation, therefore, plays a critical role in preserving the native chemical composition for SIMS analysis. This work focuses on the evaluation of frozen-hydrated and frozen freeze-dried sample preparations for SIMS studies of cultured cells with a CAMECA IMS-3f dynamic SIMS ion microscope instrument capable of producing SIMS images with a spatial resolution of 500 nm. The sandwich freeze-fracture method was used for fracturing the cells. The complimentary fracture planes in the plasma membrane were characterized by field-emission secondary electron microscopy (FESEM) in the frozen-hydrated state. The cells fractured at the dorsal surface were used for SIMS analysis. The frozen-hydrated SIMS analysis of individual cells under dynamic primary ion beam (O 2 + ) revealed local secondary ion signal enhancements correlated with the water image signals of 19 (H 3 O) + . A preferential removal of water from the frozen cell matrix in the Z-axis was also observed. These complications render the frozen-hydrated sample type less desirable for subcellular dynamic SIMS studies. The freeze-drying of frozen-hydrated cells, either inside the instrument or externally in a freeze-drier, allowed SIMS imaging of subcellular chemical composition. Morphological evaluations of fractured freeze-dried cells with SEM and confocal laser scanning microscopy (CLSM) revealed well-preserved mitochondria, Golgi apparatus, and stress fibers. SIMS analysis of fractured freeze-dried cells revealed well-preserved chemical composition of even the most highly diffusible ions like K + and Na + in physiologically relevant concentrations. The high K-low Na signature in individual cells

  12. Rotating target wheel system for super-heavy element production at ATLAS

    CERN Document Server

    Greene, J P; Falout, J; Janssens, R V F

    2004-01-01

    A new scattering chamber housing a large diameter rotating target wheel has been designed and constructed in front of the Fragment Mass Analyzer (FMA) for the production of very heavy nuclei (Z greater than 100) using beams from the Argonne Tandem Linear Accelerator System (ATLAS). In addition to the target and drive system, the chamber is extensively instrumented in order to monitor target performance and deterioration. Capabilities also exist to install rotating entrance and exit windows for gas cooling of the target within the scattering chamber. The design and initial tests are described.

  13. Structure effects in the region of superheavy elements via the α-decay chain of 293118

    International Nuclear Information System (INIS)

    Gupta, Raj K; Kumar, Sushil; Kumar, Rajesh; Balasubramaniam, M; Scheid, W

    2002-01-01

    The α-decay chain of 293 118, first proposed in the Berkeley cold fusion experiment 208 Pb( 86 Kr, 1n) and now retracted, is calculated by using the preformed cluster model (PCM) of one of the authors (RKG). Also, the possible branchings of α-decays to heavier cluster decays of all the parents in this chain are calculated for the first time. The calculated Q-values, penetrabilities and preformation factors for α-decays suggest that the 285 114 nucleus with Z=114, N=171 is a magic nucleus, either due to the magicity of Z=114, or N=172 or both. The N=172 is proposed to be a magic number in certain relativistic mean-field calculations, but with Z 120. The calculated cluster decays point to new interesting possibilities of 14 C decay of the 281 112 parent, giving rise to a (reasonably) deformed Z=106, N=161, 267 106 daughter (N=162 being now established as the deformed magic shell) or to a doubly magic 48 Ca cluster emitted from any of the parent nucleus in the α-decay chain. Apparently, these are exciting new directions for future experiments

  14. Perspectives for nuclear structure research at GSI: from halo nuclei to superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Muenzenberg, G.

    1997-11-01

    After a brief overview on recent advances in the investigation of nuclei at the driplines and the upper end of the nuclear table key issues of nuclear structure research as adressed by new theoretical developments will be discussed in context with new developments in heavy-ion accelerators and experimental techniques. (orig.)

  15. Perspectives for nuclear structure research at GSI--from halo nuclei to superheavy elements

    International Nuclear Information System (INIS)

    Munzenberg, G.

    1997-01-01

    After a brief overview on recent advances in the investigation of nuclei at the drip lines and the upper end of the nuclear table key issues of nuclear structure research as addressed by new theoretical developments will be discussed in context with new developments in heavy-ion accelerators and experimental techniques

  16. Rare earths: critical elements for various applications and challenges in their separation

    International Nuclear Information System (INIS)

    Singh, D.K.; Chakravartty, J.K.

    2015-01-01

    High purity rare earths oxides, metal and alloys find wide applications in high tech area such as nuclear energy, permanent magnets, materials for storing hydrogen, phosphors, laser, etc. Rare earths consists a group of 15 elements from La to Lu in the periodic table and it also includes Sc and Y. Due to similar chemical nature owing to common oxidation state of +3, rare earths are very difficult to separate from each other. They have very low separation factors with acidic extractants like D2EHPA and EHEHPA and hence require large number of stages in various cascade of extraction process. Monazite (a source of rare earths, thorium and uranium) is processed at IREL to separate rare earths from thorium and uranium. The rare earths are fractionated into three groups namely light rare earths (LRE), middle rare earths (MRE) and heavy rare earths (HRE) by solvent extraction method employing EHEHPA as extractant

  17. Developing alternative resources of rare earth elements in Europe - EURARE and the red mud challenge

    Science.gov (United States)

    Deady, Eimear; Mouchos, Evangelos; Goodenough, Kathryn; Wall, Frances; Williamson, Ben

    2015-04-01

    Rare earth elements (REE) are considered to be highly "critical" by the European Commission [1], owing to the concentration of global supply [2] and their use in a wide range of emerging technologies (e.g. smart phones, electric cars and wind turbines). The main source of REE is the mineral bastnäsite, which is primarily extracted from carbonatites. Alternative resources of REE have been identified in a variety of other environments such as alluvial placers, bauxites and ore tailings. The EURARE project (www.eurare.eu), funded by the European Commission, aims to improve understanding of potential REE resources in Europe with the overall objective of establishing the basis for a European REE industry. As a part of this project, alternative sources of rare earth elements in Europe are being considered. REE have been identified as being particularly enriched in karst-bauxites and hence in the red muds generated as a waste product from the processing of these bauxites to alumina through the Bayer process [3]. Karst-bauxites are widely distributed with deposits known across the Mediterranean and with intermittent exploitation occurring over many decades. REE become concentrated in the bauxite deposits by the bauxitisation process and are retained due to the geochemical barrier created by the limestone bedrock below. This can result in several processes, including the crystallisation of authigenic REE-bearing minerals, the accumulation of residual phases and the adsorption of ions onto clays and other mineral surfaces [4]. Red muds produced from alumina processing represent a potentially important concentration of REE as it has been demonstrated that the REE pass through the alumina extraction process into the waste, and the total REE concentrations are typically enriched by a factor of two compared with the original bauxite ore [5]. Bauxites and red muds from the Parnassus Ghiona region of Greece [6] and the Seydişehir-Akseki region of Turkey have been assessed as

  18. Alguns aspectos históricos da classificação periódica dos elementos químicos Some historical aspects of the periodic classification of the chemical elements

    Directory of Open Access Journals (Sweden)

    Mario Tolentino

    1997-02-01

    Full Text Available A history of the periodic table of the elements is presented, from the first tentative classifications, passing through Meyer and Mendeleev, up to recent speculations on super-heavy elements still to be synthesized. Many of the discussions and discoveries related to chemical elements and their proper periodic classification are also presented.

  19. Superheavy contributions to FCNC in the flipped SU(5) x U(1)

    Energy Technology Data Exchange (ETDEWEB)

    Gabbiani, F.; Masiero, A.

    1988-08-04

    In the supersymmetric GUT's the presence of the superheavy fields yields new contributions to flavour-changing neutral-current effects at low energy. We analyse this phenomenon in the context of the flipped SU(5) x U(1) superstring (-inspired) model. We show that possibly sizeable flavour leptonic changes (..mu.. -> e..gamma.., ..mu.. -> eeanti e, ..mu..-e conversion in nuclei) are generated. K-anti K, B-anti B mixings and b -> s..gamma.. constrain new couplings at the superlarge scale, which are unrelated to the standard Yukawa coefficients.

  20. Neutron and Proton Diffusion in Fusion Reactions for the Synthesis of Superheavy Nuclei

    International Nuclear Information System (INIS)

    Ming-Hui, Huang; Zai-Guo, Gan; Zhao-Qing, Feng; Xiao-Hong, Zhou; Jun-Qing, Li

    2008-01-01

    The restriction of the one dimensional (1D) master equation (ME) with the mass number of the projectile-like fragment as a variable is studied, and a two-dimensional (2D) master equation with the neutron and proton numbers as independent variables is set up, and solved numerically. Our study showed that the 2D ME can describe the fusion process well in all projectile-target combinations. Therefore the possible channels to synthesize super-heavy nuclei can be studied correctly in wider possibilities. The available condition for employing 1D ME is pointed out

  1. Effects of high-order deformation on high-K isomers in superheavy nuclei

    International Nuclear Information System (INIS)

    Liu, H. L.; Bertulani, C. A.; Xu, F. R.; Walker, P. M.

    2011-01-01

    Using, for the first time, configuration-constrained potential-energy-surface calculations with the inclusion of β 6 deformation, we find remarkable effects of the high-order deformation on the high-K isomers in 254 No, the focus of recent spectroscopy experiments on superheavy nuclei. For shapes with multipolarity six, the isomers are more tightly bound and, microscopically, have enhanced deformed shell gaps at N=152 and Z=100. The inclusion of β 6 deformation significantly improves the description of the very heavy high-K isomers.

  2. Superheavy particles in cosmology and evolution of inhomogeneities in the early universe

    International Nuclear Information System (INIS)

    Khlopov, M. Yu.; Polnarev, A.G.

    1983-01-01

    The stages of dominance of superheavy metastable particles, predicted by GUTs, are shown to result in the formation of primordial black holes (PBH) in the course of evolution of small initial inhomogeneities. The minimal probability of PBH formation is estimated. The relationship between the spectrum of these PBH, the spectrum of initial metric fluctuations and the parameters of the GUTs is established. Observational astrophysical restrictions on the PBH spectrum then provide a number of restrictions on the parameters of the GUTs depending on the amplitude of initial metric perturbations. (author)

  3. Charge quantization without superheavy masses in a Kaluza--Klein description of electromagnetism

    International Nuclear Information System (INIS)

    Ross, D.K.

    1987-01-01

    A scalar matter field coupled to general relativity and electromagnetism in a five-dimensional Kaluza--Klein model is considered. The five-dimensional space is assumed to be a fiber bundle as in the usual description of a gauge theory and not a more general manifold. Properly taking this into account allows one to use a Lagrangian density for the scalar field which includes charge quantization but not the unphysical superheavy masses found by other authors. A natural, satisfactory explanation of why charge is quantized results

  4. True ternary fission and quasifission of superheavy nuclear systems

    Directory of Open Access Journals (Sweden)

    Greiner Walter

    2011-10-01

    Full Text Available We found that a true ternary fission with formation of a heavy third fragment (a new kind of radioactivity is quite possible for superheavy nuclei due to the strong shell effects leading to a three-body clusterization with the two doubly magic tin-like cores. The three-body quasifission process could be even more pronounced for giant nuclear systems formed in collisions of heavy actinide nuclei. In this case a three-body clusterization might be proved experimentally by detection of two coincident lead-like fragments in low-energy U+U collisions.

  5. Approach synthesis of superheavy nuclei from some aspects of cross section calculations

    International Nuclear Information System (INIS)

    Liu Zuhua

    2003-01-01

    Several important aspects in the cross section calculations for the synthesis of superheavy nuclei have been inquired. They are the effects of the coupled-channels, the damping of shell correction energy, the collective enhancements in the level density and the spin distributions of evaporation residues. The channel coupling of relative motion with internal degrees of freedom will enhance significantly the capture cross section at sub-barrier energies. However, recent measurements of spin distributions for the survived compound nucleus show that only low partial waves contribute to the evaporation residues, which should at least partially cancel out the enhancement due to the effects of the channel coupling. The fission barriers are determined mainly by the shell correction energy in the case of superheavy nuclei. Therefore, it is especially important to determine as accurate as possible the damping parameter which describes the decrease of the shell effects influence. In addition, the collective enhancement factor in the level density also plays a very important role in the synthesis of heavy spherical nuclei

  6. Contributions to the theory of alpha disintegration of heavy and superheavy nuclei

    International Nuclear Information System (INIS)

    Tarnoveanu, G.I.

    1977-01-01

    Alpha disintegration of heavy and super-heavy spherical nuclei is studied. When the new calculation technique for alpha intensities dependent on the shell-model has been applied, a technique which allows the use of a more complex structure of the alpha particle, the detailed calculation of the alpha half-times is performed for both radioactive alpha nuclei in the lead area and for the super-heavy nuclei, by using the R matrix theory of alpha disintegration independent of the channel radius. The relative values of overlap integrals calculated by means of the intrinsic function for the Gauss and Moshinsky type alpha particle are presented, as well as a comparison between them and the experiment values for 8.6, 9.00 and 9.6 fm channel radii in the case of Po, Ra, Rn and Th isotopes. Original contributions to the alpha disintegration theory are represented by the generalization of the Taylor series method expressing the transformations to the centre of mass, and the relative distance from two particles to four particles in the same harmonic oscillator potential, and by the development of the R matrix theory for alpha disintegration independent of the channel radius in the case of complex structured alpha particles. (author)

  7. Charge-exchange resonances and restoration of Wigner’s supersymmetry in heavy and superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Lutostansky, Yu. S., E-mail: lutostansky@yandex.ru; Tikhonov, V. N. [National Research Center Kurchatov Institute (Russian Federation)

    2016-11-15

    Various facets of the question of whether Wigner’s supersymmetry [SU(4) symmetry] may be restored in heavy and superheavy nuclei are analyzed on the basis of a comparison of the results of calculations with experimental data. The energy difference between the giant Gamow–Teller resonance and the analog resonance (the difference of E{sub G} and E{sub A}) according to calculations based on the theory of finite Fermi systems is presented for the case of 33 nuclei for which experimental data are available. The calculated difference ΔE{sub G–A} of E{sub G} and E{sub A} tends to zero in heavier nuclei, showing evidence of the restoration of Wigner’s SU(4) symmetry. Also, the isotopic dependence of the Coulomb energy difference between neighboring isobaric nuclei is analyzed within the SU(4) approach for more than 400 nuclei in the mass-number range of A = 5–244. The restoration of Wigner’s SU(4) symmetry in heavy nuclei is confirmed. It is shown that the restoration of SU(4) symmetry is compatible with the possible existence of the stability island in the region of superheavy nuclei.

  8. Neutrino masses and superheavy dark matter in the 3-3-1-1 model

    Energy Technology Data Exchange (ETDEWEB)

    Huong, D.T.; Dong, P.V. [Vietnam Academy of Science and Technology, Institute of Physics, Hanoi (Viet Nam)

    2017-04-15

    In this work, we interpret the 3-3-1-1 model when the B - L and 3-3-1 breaking scales behave simultaneously as the inflation scale. This setup not only realizes the previously achieved consequences of inflation and leptogenesis, but also provides new insights in superheavy dark matter and neutrino masses. We argue that the 3-3-1-1 model can incorporate a scalar sextet, which induces both small masses for the neutrinos via a combined type I and II seesaw and large masses for the new neutral fermions. Additionally, all the new particles have large masses in the inflation scale. The lightest particle among the W-particles that have abnormal (i.e., wrong) B - L number in comparison to those of the standard model particles may be superheavy dark matter as it is stabilized by W-parity. The dark matter candidate may be a Majorana fermion, a neutral scalar, or a neutral gauge boson, which was properly created in the early universe due to gravitational effects on the vacuum or thermal production after cosmic inflation. (orig.)

  9. The challenges of translating culturally specific elements: the case of Mikhail Bulgakov’s The Master and Margarita

    Directory of Open Access Journals (Sweden)

    Natalia Kaloh Vid

    2016-12-01

    Full Text Available Mikhail Bulgakov’s novel The Master and Margarita, a highly complex and multi-levelled narrative, is a challenge for any translator. The emphasis in the current research is on the translation strategies used when translating culturally-specific elements, or historical realia, referred to as “Sovietisms,” in three English translations of the novel by Glenny (1967, Pevear and Volokhonsky (1997 and Aplin (2008. Sovietisms refer to items characteristic of the Soviet discourse of the 1930s: word-formations of the non-standard “Soviet Russian.” Bulgakov’s language is sated with Soviet vocabulary, which refers to various cultural and socio-political elements of Soviet reality. Sovietisms occur at various levels (lexical,syntactic, stylistic and rhetorical and should be carefully translated as a significant characteristic of Bulgakov’s style. A complete domestication of Sovietisms may lead to a loss of a connotative meaning essential for understanding the context, while a foreignisation of these terms, which are most likely unknown to western readers, may disturb fluidity of reading and cause confusion. The purpose of this analysis, thus, is to illustrate the use of domesticating/foreignising strategies employed by Bulgakov’s translators and to assess the translation choices. The comparative analysis employs the taxonomies suggested by Vlakhov and Florin (1995 and Vinay and Darbelnet (1958/1989 as the grounds for the case study.

  10. Synthesis of a New Element with Atomic Number Z=117

    International Nuclear Information System (INIS)

    Oganessian, Yu. Ts.; Abdullin, F. Sh.; Dmitriev, S. N.; Itkis, M. G.; Lobanov, Yu. V.; Mezentsev, A. N.; Polyakov, A. N.; Sagaidak, R. N.; Shirokovsky, I. V.; Subbotin, V. G.; Sukhov, A. M.; Tsyganov, Yu. S.; Utyonkov, V. K.; Voinov, A. A.; Vostokin, G. K.; Bailey, P. D.; Benker, D. E.; Ezold, J. G.; Porter, C. E.; Riley, F. D.

    2010-01-01

    The discovery of a new chemical element with atomic number Z=117 is reported. The isotopes 293 117 and 294 117 were produced in fusion reactions between 48 Ca and 249 Bk. Decay chains involving 11 new nuclei were identified by means of the Dubna gas-filled recoil separator. The measured decay properties show a strong rise of stability for heavier isotopes with Z≥111, validating the concept of the long sought island of enhanced stability for superheavy nuclei.

  11. On the spectroscopy of the 1ssigma-orbital in superheavy collision systems

    International Nuclear Information System (INIS)

    Stiebing, K.E.; Schmidt-Boecking, H.; Schadt, W.; Bethge, K.; Mokler, P.H.; Bosch, F.; Liesen, D.; Vincent, P.

    1982-01-01

    The probability for the emission of quasimolecular K-radiation (K-MO-radiation) in superheavy collision systems was measured in the system 208 Pb + 208 Pb as function of the scattering angle and the photon energy for incident energies of 4.3 and 4.8 MeV/u. In the present article these measurements and their evaluation are extensively described. The results are discussed with special regards to the contributions from the 1ssigma-molecular orbital, because there exists a great interest on an utmost precise knowledge of the binding energy of these most strongly bound electrons. For this a survey about the dynamical model of the emission of quasimolecular X-radiation in the configuration formalism is given. (orig./HSI) [de

  12. Binary fragmentation based studies for the near super-heavy compound nucleus {sup 256}Rf

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, Meenu; Behera, B.R.; Mahajan, Ruchi; Kaur, Gurpreet; Sharma, Priya; Kapoor, Kushal; Rani, Kavita [Panjab University, Department of Physics, Chandigarh (India); Saneesh, N.; Dubey, R.; Yadav, A.; Sugathan, P.; Jhingan, A.; Chatterjee, A.; Chatterjee, M.B. [Inter University Accelerator Centre, New Delhi (India); Kumar, Neeraj; Mandal, S. [University of Delhi, Department of Physics and Astrophysics, Delhi (India); Kumar, S. [Andhra University, Department of Nuclear Physics, Visakhapatnam (India); Saxena, A.; Kailas, S. [Bhabha Atomic Research Centre, Nuclear Physics Division, Mumbai (India); Pal, Santanu [CS, Kolkata (India); Nasirov, Avazbek [JINR, Bogoliubov Laboratory of Theoretical Physics, Dubna (Russian Federation); National University, Department of Physics, Tashkent (Uzbekistan); Kayumov, Bakhodir [National University, Department of Physics, Tashkent (Uzbekistan)

    2017-06-15

    Binary fragmentation of the near super-heavy compound nucleus {sup 256}Rf has been studied through the reaction {sup 48}Ti + {sup 208}Pb at a bombarding energy well above the Coulomb barrier. For a better understanding of its reaction dynamics, the mass distribution, mass-energy distribution and mass-angle distribution of the fission fragments produced from {sup 256}Rf have been investigated thoroughly. The masses and kinetic energies of the fission fragments were reconstructed event-by-event from their measured velocities and emission angles. From the mass-energy analysis, a sizeable contribution from the asymmetric fission was observed on the edges of symmetric mass distribution. Evidence of asymmetric fission was also clued from the observed correlation between the masses and emission angles of the fission fragments. Contribution of the quasi-fission products has also been estimated by performing the theoretical dinuclear system calculations. (orig.)

  13. Ionization history of the universe as a test for superheavy dark matter particles

    International Nuclear Information System (INIS)

    Doroshkevich, A.G.; Naselsky, P.D.

    2002-01-01

    In this paper we discuss the possible distortions of the ionization history of the universe caused by an injection of nonthermal energy due to decays of hypothetical superheavy dark matter (SHDM) particles. These particles are usually considered as a possible source of ultrahigh energy cosmic rays in the framework of the top-down model. Estimates of the fraction of energy of decays converted to the UV range show that, for suitable parameters of the SHDM particles, significant distortions of the power spectra of the cosmic microwave background anisotropy appear. A comparison with the observed power spectrum allows us to restrict some properties of the SHDM particles. These decays can also increase by about 5-10 times the degree of ionization of hydrogen at redshifts z∼10-50, which essentially accelerates the formation of molecules of H 2 and the first stars during the 'dark ages'

  14. Towards Superheavies: Spectroscopy of 94 < Z < 98, 150 < N < 154 Nuclei

    Directory of Open Access Journals (Sweden)

    Chowdhury P.

    2016-01-01

    nuclear structure studies are important testing grounds for theoretical models that aim to describe superheavy nuclei. To study the highest neutron orbitals (150 ≤ N ≤ 154, we have populated high angular momentum states in a series of Pu (Z = 94, Cm (Z = 96 and Cf (Z = 98 nuclei, via inelastic and transfer reactions, with heavy beams on long-lived radioactive actinide targets. Multiple collective excitation modes and structures were identified, and their configurations deduced. Quasiparticle alignments are mapped, with odd-A band structures helping identify specific orbital contributions via blocking arguments. Higher-order multipole shapes are observed to play a significant role in disentangling competing neutron and proton alignments. The N > 152 data provide new perspectives on physics beyond the N = 152 sub-shell gap.

  15. Search for super-heavy GUT magnetic monopoles in cosmic rays

    International Nuclear Information System (INIS)

    Shepko, M.J.

    1986-05-01

    A search for superheavy grand unified (GUT) magnetic monopoles has been performed utilizing a large (260m 2 sr) array of scintillation counters, sited underground at a depth of 1200 m.w.e. This apparatus measures both the time of flight and specific ionization of particles passing through it and has a trigger which is sensitive to prompt as well as very slowly developing pulses from the detector. No monopole events have been observed during 280 days of live time operation of this detector. An upper limit on the flux of monopoles of 4.6 x 10 -14 cm -2 sr -1 s -1 is obtained in the velocity range 8.5 x 10 -4 c to 0.012c at a 90% confidence level. 50 refs., 47 figs., 16 tabs

  16. Chemistry of the actinide elements. Second edition

    International Nuclear Information System (INIS)

    Katz, J.J.; Seaborg, G.T.; Morss, L.R.

    1987-01-01

    This is an exhaustive, updated discourse on the chemistry of Actinides, Volume 1 contains a systematic coverage of the elements Ac, Th, Pa, U, Np, and Pu, which constitutes Part 1 of the work. The characterization of each element is discussed in terms of its nuclear properties, occurrence, preparation, atomic and metallic properties, chemistry of specific compounds, and solution chemistry. The first part of Volume 2 follows the same format as Volume 1 but is confined to the elements Am, Cm, Bk, Cf, and Es, plus a more condensed coverage of the Transeinsteinium elements (Fm, Md, No, Lw, and 104-109). Part 2 of this volume is devoted to a discussion of the actinide elements in general, with a specific focus on electronic spectra, thermodynamic and magnetic properties, the metallic state, structural chemistry, solution kinetics, organometallic chemistry for σ- and π-bonded compounds, and some concluding remarks on the superheavy elements

  17. The Determination of Current Challenges and Potentials in Each of the Main Elements of Social Harms in Tehran

    Directory of Open Access Journals (Sweden)

    H. A. Gafari

    2016-10-01

    Full Text Available This study is an attempt to monitor and investigate the main elements of social harms from political, economic, sociocultural, technological, environmental and legal perspectives in accordance with the factors of PESTEL. One of the findings of the present study indicates that Iran has taken several measures in order to fight narcotics.  In poverty and unemployment, it must be admitted that casting shadow of global economic situation on Iran's economy along with failure to implement Article 44 on the Constitution have led to the fact that a considerable section of the country’s economy has remained under direct government control. It seems that broadcasting performance has been weak from cultural perspective; this issue has caused satellite networks intrusion on the culture of people. No organization instructs young generation in life skills and how to prevent from divorce. This problem together with lack of life facilities has caused many marriages to end in divorce within the first year. Considering limited financial resources, the municipality and its affiliated organizations have had a quite good performance in organizing homeless people, but it is not sufficient. Donations contributing to susceptible classes of society are assessed absolutely positive and worthwhile. Street children are considered as an increasing harm in the world and Iran. If we do not reflect on some strategies in order to address this issue, it will be converted to a social crisis. Beggary has a significant manifestation in megacities as a social harm and challenge; it is mostly assumed to be a social dilemma rather than an individual problem. It can be really influential to educate people how to behave with beggars.

  18. My journey to the superheavy island with Szymanski, Nilsson, Nix, and Swiatecki from Lysekil to the present

    International Nuclear Information System (INIS)

    Mueller, Peter

    2010-01-01

    We discuss the great theoretical insights on nuclear stability that emerged in the late 1960s, especially the realization that observable nuclei might include a superheavy island 20+ protons beyond uranium with 92 protons. However, we now realize that the early models were not sufficiently quantitative to yield definite conclusions. Further groundwork for such models was laid in the 1970s. Around 1980 more quantitative, global and universal models appeared and together with experimental advances the mapping of the superheavy island, or as it turns out now, continent started in earnest. We review these early developments and conclude with some examples of our current insights. In particular, 1) some theoretical models do have predictive capabilities for nuclear properties such as ground-state masses, shapes, and half-lives 10 or more neutrons and protons away from previously known regions and 2) the superheavy island may be a continent connected to the actinides by a narrow land bridge; the continent itself may extend from about proton number Z = 110 to Z = 120 or slightly beyond. (author)

  19. PIXE analysis showed that the preirradiation enhanced recovery of bone marrow elements after challenging irradiation in C57BL/6N Mice

    International Nuclear Information System (INIS)

    Matsuda, Y.; Yonezawa, M.; Nishiyama, F.

    2000-01-01

    Priming X-irradiation with 0.3-0.5 Gy induces radio-resistance in C57BL/6 strain of mice 2 weeks afterward. Elements in the bone marrow, sampled 11 days after challenging exposure to 5.0 Gy, were determined by PIXE. The challenging irradiation decreased Mg, P, S, K, Ca and Zn as well as dried bone marrow weight. The pre-irradiation enhanced recovery of these levels, indicating stimulated recovery of the metabolism int he tissue. Fe in both control (without pre-irradiation) and experimental groups increased to about twice the original value, showing elevated hemoglobin synthesis after challenging exposure. In previous studies we have reported that recovery of peripheral blood cell counts after sub-lethal irradiation was enhanced by the pre-irradiation. Further, study on accumulation of p53 and Bax proteins, which lead to apoptotic cell death, revealed that the pre-irradiation significantly suppressed accumulation of these proteins in the spleen after challenging irradiation with 3 Gy. These results and our present study suggest that the pre-irradiation decreased the spleen cell death, and favored re-growth of the spleen cells, resulting in stimulated recovery of metabolism for hematopoiesis in the bone marrow as well as in the spleen after challenging high dose irradiation. Stimulated recovery of Mg, P, S, K, Ca and Zn levels might indicate the importance of these elements in hematopoiesis. (author)

  20. Search for isobar-analog states of superheavy hydrogen isotopes5-7He

    Science.gov (United States)

    Chernyshev, B. A.; Gurov, Yu B.; Korotkova, L. Yu; Kuznetsov, D. S.; Lapushkin, S. V.; Tel'kushev, M. V.; Schurenkova, T. D.

    2016-02-01

    Search for isobar-analog states (IAS) of superheavy hydrogen isotopes 5-7H was performed among the high-excited states of helium isotopes 5-7He. The excited spectra were measured in stopped pion absorption by light nuclei. The experiment was performed at low energy pion channel of LANL with two-arm multilayer semiconductor spectrometer. Excited states of 5-7He were observed in three-body reaction channels on 10,11B nuclei. Several excited levels were observed for the first time. 6He excited state with Ex = 27.0(8) MeV observed in 10B(π-,pt)X channel is an IAS candidate for 6H with Er ∼ 5.5 MeV. 7He excited state with Ex = 24.8(4) MeV observed in 10B(π-,pd)X, nB(π-,pt)X and nB(π-,dd)X channels is an IAS candidate for 7H with Er ∼ 3 MeV.

  1. Probing the stability of superheavy dark matter particles with high-energy neutrinos

    International Nuclear Information System (INIS)

    Esmaili, Arman; Peres, O.L.G.

    2012-01-01

    Full text: There is currently mounting evidence for the existence of dark matter in our Universe from various astrophysical and cosmological observations, but the two of the most fundamental properties of the dark matter particle, the mass and the lifetime, are only weakly constrained by the astronomical and cosmological evidence of dark matter. We derive lower limits on the lifetime of dark matter particles with masses in the range 10 TeV - 10 18 GeV from the non-observation of ultrahigh energy neutrinos in the AMANDA, IceCube, Auger and ANITA experiments. All these experiments probe different energy windows and perfectly complement each other. For dark matter particles which produce neutrinos in a two body or a three body decay, we find that the dark matter lifetime must be longer than ∼ 10 26 s for masses between 10 TeV and the Grand Unification scale. We will consider various scenarios where the decay of the dark matter particle produces high energy neutrinos. Neutrinos travel in the Universe without suffering an appreciable attenuation, even for EeV neutrinos, in contrast to photons which rapidly lose their energy via pair production. This remarkable property makes neutrinos a very suitable messenger to constrain the lifetime of superheavy dark matter particles. Finally, we also calculate, for concrete particle physics scenarios, the limits on the strength of the interactions that induce the dark matter decay. (author)

  2. Search for surviving actinides and superheavy nuclei in damped collisions of 238U with 238U and 248Cm

    International Nuclear Information System (INIS)

    Kratz, J.V.

    1980-03-01

    In the present talk aspects of the reaction mechanism related to the survival probability of the heaviest fragments in 238 U + 238 U collisions are discussed first. This is followed by a description of the experiments that have been performed to search for surviving superheavy fragments in the 238 U + 238 U reaction and by a presentation of the results obtained so far. In a third section our recent first attempts with the 238 U + 248 Cm reaction are described and preliminary results are discussed. (orig.)

  3. Nuclear Structure of the Heaviest Elements – Investigated at SHIP-GSI

    Directory of Open Access Journals (Sweden)

    Heßberger Fritz Peter

    2014-03-01

    Full Text Available The quest for the heaviest nuclei that can exist is a basic topic in natural science as their stability is characterized by a delicate interplay of short range nuclear forces acting between the nucleons (protons and neutrons and long-range Coulomb forces acting solely between charged particles, i.e. the protons. As the stability of a nucleus is strongly correlated to its structure, understanding the nuclear structure of heaviest nuclei is presently a main challenge of experimental and theoretical investigations concerning the field of Superheavy Elements. At the velocity filter SHIP at GSI Darmstadt an extensive program on nuclear structure investigations has been started about a decade ago. The project covered both as well systematic investigations of single particle levels in odd-mass isotopes populated by α-decay as investigation of two- or fourquasi-particle states forming K isomers and was supplemented by direct mass measurements at SHIPTRAP and investigation of spontaneous fission properties. Recent experimental studies allowed to extend the systematics of low lying levels in N = 151 and N = 153 up to 255Rf and 259Sg, investigation of possible relations between nuclear structure and fission properties of odd-mass nuclei and investigation of shell strengths at N = 152 and towards N = 162.

  4. The predictive accuracy of analytical formulas and semiclassical approaches for α decay half-lives of superheavy nuclei

    Science.gov (United States)

    Zhao, T. L.; Bao, X. J.; Guo, S. Q.

    2018-02-01

    Systematic calculations on the α decay half-lives are performed by using three analytical formulas and two semiclassical approaches. For the three analytical formulas, the experimental α decay half-lives and {Q}α values of the 66 reference nuclei have been used to obtain the coefficients. We get only four adjustable parameters to describe α decay half-lives for even-even, odd-A, and odd-odd nuclei. By comparison between the calculated values from ten analytical formulas and experimental data, it is shown that the new universal decay law (NUDL) foumula is the most accurate one to reproduce the experimental α decay half-lives of the superheavy nuclei (SHN). Meanwhile it is found that the experimental α decay half-lives of SHN are well reproduced by the Royer formula although many parameters are contained. The results show that the NUDL formula and the generalized liquid drop model (GLDM2) with consideration of the preformation factor can give fairly equivalent results for the superheavy nuclei.

  5. The synthesis and decay properties of the heaviest elements

    International Nuclear Information System (INIS)

    Oganesyan, Yu.Ts.

    2000-01-01

    The synthesis and the study of radioactive properties of new elements is considered with respect to the existence of the 'islands of stability' of hypothetical superheavy elements predicted by the theory more than 35 years ago. Experimental data demonstrating an enhanced stability of nuclei in the vicinity of deformed shells with Z=108 and N=162 is discussed from the point of view of advent into more heavy and much more stable nuclides near the predicted spherical shells Z=114-122 and N=184 following after the doubly magic nucleus 208 Pb. The author presents the results of experiments on the synthesis of isotopes of elements 114 and 116 in the fusion reactions with 48 Ca. In these reactions the decay chains of heavy atoms consisting of sequential α-decays interrupted by spontaneous fission have been observed. The decay energies and probabilities are compared with predictions of different theoretical models describing the structure of heavy nuclei. The obtained results are considered as the first experimental evidence of the existence of domains of stability of superheavy nuclei which substantially extends the boundaries of existence of chemical elements

  6. On The Cusp of the New Spatial Challenges - The Thermal Waste Processing Plant as an Element of Urban Space

    Science.gov (United States)

    Wójtowicz-Wróbel, Agnieszka

    2017-10-01

    The goal of this paper is to answer the question about the current importance of structures associated with the thermal processing of waste within the space of Polish cities and what status can they have in the functional and spatial structure of Polish cities in the future. The construction of thermal waste processing plants in Poland is currently a new and important problem, with numerous structures of this type being built due to increasing care for the natural environment, with the introduction of legal regulations, as well as due to the possibility of obtaining large external funding for the purposes of undertaking pro-environmental spatial initiatives, etc. For this reason, the paper contains research on the increase in the number of thermal waste processing plants in Poland in recent years. The abovementioned data was compared with similar information from other European Union member states. In the group containing Polish thermal waste processing plants, research was performed regarding the stage of the construction of a plant (operating plant, plant under construction, design in a construction phase, etc.). The paper also contains a listing of the functions other than the basic form of use, which is the incineration of waste - similarly to numerous foreign examples - that the environmentally friendly waste incineration plants fulfil in Poland, dividing the additional forms of use into "hard" elements (at the design level, requiring the expansion of a building featuring new elements that are not directly associated with the basic purpose of waste processing) and soft (social, educational, promotional actions, as well as other endeavours that require human involvement, but that do not entail significant design work on the buildings itself, expanding its form of use, etc.) as well as mixed activity, which required design work, but on a relatively small scale. Research was also conducted regarding the placement of thermal waste processing plants within the

  7. Synthesis of the New Element with Z=117

    International Nuclear Information System (INIS)

    Hamilton, J H; Ramayya, A V; Oganessian, Yu Ts; Abdullin, F Sh; Dmitriev, S N; Itkis, M G; Lobanov, Yu V; Mezentsev, A N; Polyakov, A N; Bailey, P D; Benker, D; Ezold, J; Porter, C E; Riley, F; Roberto, J B; Bennett, M E; Henderson, R A; Moody, K J; Nelson, S L; Ryabinin, M A

    2011-01-01

    The synthesis of the new chemical element with atomic number Z=117 is presented. The isotopes 293 117 and 294 117were produced in fusion reactions between 48 Ca and 249 Bk. The 249 Bk was produced in the High Flux Isotope Reactor and chemically separated at Oak Ridge. Decay chains involving eleven new nuclei were identified by means of the Dubna Gas Filled Recoil Separator. The measured decay properties show a strong rise of stability for super-heavy nuclei toward N=184.

  8. The challenges in developing a finite element injury model of the neck to predict the penetration of explosively propelled projectiles.

    Science.gov (United States)

    Breeze, Johno; Newbery, T; Pope, D; Midwinter, M J

    2014-09-01

    Neck injuries sustained by UK service personnel serving on current operations from explosively propelled fragments result in significant mortality and long-term morbidity. Many of these injuries could potentially have been prevented had the soldiers been wearing their issued neck collars at the time of injury. The aim of this research is to develop an accurate method of predicting the resultant damage to cervical neurovascular structures from explosively propelled fragments. A finite element numerical model has been developed based on an anatomically accurate, anthropometrically representative 3D mathematical mesh of cervical neurovascular structures. Currently, the model simulates the passage of a fragment simulating projectile through all anatomical components of the neck using material models based upon 20% ballistic gelatin on the simplification that all tissue types act like homogenous muscle. The material models used to define the properties of each element within the model will be sequentially replaced by ones specific to each individual tissue within an anatomical structure. However, the cumulative effect of so many additional variables will necessitate experimental validation against both animal models and post-mortem human subjects to improve the credibility of any predictions made by the model. We believe this approach will in the future have the potential to enable objective comparisons between the mitigative effects of different body armour systems to be made with resultant time and financial savings. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  9. The discovery of elements 107 to 112

    Directory of Open Access Journals (Sweden)

    Hofmann Sigurd

    2016-01-01

    Full Text Available In the 1960s, theoretical concepts prepared the path to nuclear matter with proton and neutron numbers far beyond the nuclei known at that time. The new laboratory GSI was founded for research on reactions with heavy ions, in particular those for production of the predicted super-heavy nuclei. In this contribution it is presented how the interaction between experiment and theory resulted in a continuous improvement of the experimental set-ups on the one hand, and of the knowledge of the processes during the nuclear reaction and of the properties of the produced nuclei on the other hand. In the course of this work six new elements from 107 to 112 were produced and identified. An overview of the present status of experimental results and a comparison with theoretical interpretations is given.

  10. Production of the superheavy baryon Λ{sub c} {sub anti} {sub c}{sup *}(4209) in kaon-induced reaction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiao-Yun [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); University of Chinese Academy of Sciences, Beijing (China); Institute of Modern Physics of CAS and Lanzhou University, Research Center for Hadron and CSR Physics, Lanzhou (China); Chen, Xu-Rong [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Institute of Modern Physics of CAS and Lanzhou University, Research Center for Hadron and CSR Physics, Lanzhou (China)

    2015-07-15

    The production of superheavy Λ{sub c} {sub anti} {sub c}{sup *}(4209) baryon in the K{sup -}p → η{sub c}Λ process via s-channel is investigated with an effective Lagrangian approach and the isobar model. Moreover, the background from the K{sup -}p → η{sub c}Λ reaction through the t-channel with K* exchange and u-channel with nucleon exchange are also considered. The numerical results indicate it is feasible to search for the superheavy Λ{sub c} {sub anti} {sub c}{sup *}(4209) via K{sup -}p scattering. The relevant calculations not only shed light on the further experiment of searching for the Λ{sub c} {sub anti} {sub c}{sup *}(4209) through kaon-induced reaction, but also enable us to have a better understanding of the exotic baryons. (orig.)

  11. Spectroscopy of very heavy nuclei with a view to study super-heavy nuclei; Spectroscopie de noyaux tres lourds en vue de l'etude des noyaux super-lourds

    Energy Technology Data Exchange (ETDEWEB)

    Khalfallah, F

    2007-08-15

    Within the recent years, the spectroscopic study of single particle orbitals of very heavy elements (VHE) has become possible with the development of increasingly efficient experimental setups. This allows us, through nuclear deformation, to access with these deformed nuclei to orbitals situated around the Fermi level in the spherical superheavy elements (SHE) and learn more about the nuclear structure of these nuclei. The aim of this work is the spectroscopic studies of heavy and very heavy elements. Because of the experimental difficulties associated with the fusion reactions in the VHE region, a detailed optimization studies is essential. Simulation of energy loss and angular straggling of these nuclei due to the interaction in the target and to neutron's evaporation was carried out and allowed us to optimize the angular acceptance of the separators according to the target thickness. An extensive survey and exploration in the VHE region was also conducted on the basis of cross section's systematics in the literature and simulations carried out using the statistical code Hivap. In this framework, the possible extension of the range of validity of a set of Hivap parameters was investigated. This work has enabled us to prepare a list of experiments of interest for the production of very heavy nuclei. In this thesis, our work was concentrated on the spectroscopy of the nuclei No{sup 256} et Rf{sup 256} for which two experimental proposals were accepted. The octupole deformations predicted in the actinides region is studied in another part of this thesis, a part witch is dedicated to the gamma spectroscopy of Pa{sup 223}. The data from a new experiment carried out using the Jurogam-Ritu-Great setup are analysed and compared to previous results. They confirm the octupole deformed shape in this nucleus. (author)

  12. Spallation RI beam facility and heavy element nuclear chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Nagame, Yuichiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-11-01

    An outline of the spallation RI (Radioactive Ion) beam facility is presented. Neutron-rich nuclides are produced in the reaction of high intensity (10-1000 {mu}A) protons with energy of 1.5 GeV and an uranium carbide target. Produced nuclides are ionized in an isotope separator on-line (ISOL) and accelerated by the JAERI tandem and the booster linac. Current progress and a future project on the development of the RI beam facility are given. Studies of transactinide elements, including the synthesis of superheavy elements, nuclear structure far from stability, and RI-probed material science are planned with RI beams. An outlook of the transactinide nuclear chemistry studies using neutron-rich RI beams is described. (author)

  13. Fission in the landscape of heaviest elements: Some recent examples

    International Nuclear Information System (INIS)

    Khuyagbaatar, J.; Yakushev, A.; Düllmann, Ch.E.; Ackermann, D.; Andersson, L.-L.; Block, M.; Brand, H.; Even, J.; Forsberg, University; Hartmann, W.; Herzberg, R.-D.; Heßberger, F.P.; Hoffmann, J.; Hübner, A.; Jäger, E.; Jeppsson, J.; Kindler, B.; Kratz, J.V.; Krier, J.; Kurz, N.; Lommel, B.; Maiti, M.; Minami, S.; Rudolph, D.; Runke, J.; Sarmiento, L.G.; Schädel, M.; Schausten, B.; Steiner, J.; Heidenreich, T. Torres De; Uusitalo, J.; Wiehl, N.; Yakusheva, V.

    2016-01-01

    The fission process still remains a main factor that determines the stability of the atomic nucleus of heaviest elements. Fission half-lives vary over a wide range, 10"−"1"9−10"2"4 s. Present experimental techniques for the synthesis of the superheavy elements that usually measure α-decay chains are sensitive only in a limited range of half-lives, often 10"−"5−10"3 s. In the past years, measurement techniques for very short-lived and very long-lived nuclei were significantly improved at the gas-filled recoil separator TASCA at GSI Darmstadt. Recently, several experimental studies of fission-related phenomena have successfully been performed. In this paper, results on "2"5"4"−"2"5"6Rf and "2"6"6Lr are presented and corresponding factors for retarding the fission process are discussed.

  14. Synthesis and properties of neutron deficient isotopes of elements around Z=100

    International Nuclear Information System (INIS)

    Antalic, S.

    2005-01-01

    In the presented Thesis work the results of spectroscopic studies of 246 Md, 247 Md, 254 Lr and 255 Lr decay chains are given. These isotopes were produced using heavy ion induced fusion reactions of 40 Ar + 209 Bi and 48 Ca + 209 Bi as a part of the long term project aimed to study spectroscopy properties of superheavy elements. The experiments were performed at velocity filter SHIP, placed at the central beam line of the UNILAC accelerator at GSI Darmstadt in Germany. The work also gives a basic overview of research in the region of superheavy elements, description of the used experimental setup and shows the usual analysis methods used in spectroscopic studies in the region of elements around Z ∼ 100. The results were obtained using α, α - γ spectroscopy methods and recoil - α, α - α correlations search. Although these isotopes have been known for a longer time, no detailed spectroscopy investigation were performed so far and only rough information was known. Beside the improved precision of known data, this work gives a new information about the decay properties of these isotopes. This give us the possibility to build a decay schemes for mentioned decay chains. (author)

  15. ORNL actinide materials and a new detection system for superheavy nuclei

    Directory of Open Access Journals (Sweden)

    Rykaczewski Krzysztof P.

    2016-01-01

    Full Text Available The actinide resources and production capabilities at Oak Ridge National Laboratory (ORNL are reviewed, including potential electromagnetic separation of rare radioactive materials. The first experiments at the Dubna Gas Filled Recoil Separator (DGFRS with a new digital detection system developed at ORNL and University of Tennessee Knoxville (UTK are presented. These studies used 240Pu material provided by ORNL and mixed-Cf targets made at ORNL. The proposal to use an enriched 251Cf target and a large dose of 58Fe beam to reach the N = 184 shell closure and to observe new elements with Z = 124, 122 and 120 is discussed.

  16. Shell effects in fission and quasi-fission of heavy and superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Itkis, M.G. E-mail: itkis@flnr.jinr.ru; Aeystoe, J.; Beghini, S.; Bogachev, A.A.; Corradi, L.; Dorvaux, O.; Gadea, A.; Giardina, G.; Hanappe, F.; Itkis, I.M.; Jandel, M.; Kliman, J.; Khlebnikov, S.V.; Kniajeva, G.N.; Kondratiev, N.A.; Kozulin, E.M.; Krupa, L.; Latina, A.; Materna, T.; Montagnoli, G.; Oganessian, Yu.Ts.; Pokrovsky, I.V.; Prokhorova, E.V.; Rowley, N.; Rubchenya, V.A.; Rusanov, A.Ya.; Sagaidak, R.N.; Scarlassara, F.; Stefanini, A.M.; Stuttge, L.; Szilner, S.; Trotta, M.; Trzaska, W.H.; Vakhtin, D.N.; Vinodkumar, A.M.; Voskressenski, V.M.; Zagrebaev, V.I

    2004-04-05

    Results of the experiments aimed at the study of fission and quasi-fission processes in the reactions {sup 12}C+{sup 204}Pb, {sup 48}Ca+{sup 144,154}Sm, {sup 168}Er, {sup 208}Pb, {sup 244}Pu, {sup 248}Cm; {sup 58}Fe+{sup 208}Pb, {sup 244}Pu, {sup 248}Cm, and {sup 64}Ni+{sup 186}W, {sup 242}Pu are presented in the work. The choice of the above-mentioned reactions was inspired by recent experiments on the production of the isotopes {sup 283}112, {sup 289}114 and {sup 283}116 at Dubna [1],[2] using the same reactions. The {sup 58}Fe and {sup 64}Ni projectiles were chosen since the corresponding projectile-target combinations lead to the synthesis of even heavier elements. The experiments were carried out at the U-400 accelerator of the Flerov Laboratory of Nuclear Reactions (JINR, Russia), the XTU Tandem accelerator of the National Laboratory of Legnaro (LNL, Italy) and the Accelerator of the Laboratory of University of Jyvaskyla (JYFL, Finland) using the time-of-flight spectrometer of fission fragments CORSET[3] and the neutron multi-detector DEMON[4],[5]. The role of shell effects and the influence of the entrance channel on the mechanism of the compound nucleus fusion-fission and the competitive process of quasi-fission are discussed.

  17. Effects of a superheavy, weak-isoscalar quark on flavor-changing neutral current processes, especially charge-parity violation in Z0decay

    International Nuclear Information System (INIS)

    Rivard, M.J.

    1987-01-01

    A superheavy, weak-isoscalar, Q = -1/3 quark is added to the Standard Model, inducing tree-level flavor-changing neutral currents (TLFCNCs) involving only the Q = -1/3 quarks. Although constrained by current low-energy experimental data to be extremely weak, it is nonetheless found that the tree-level s ↔ d mixing strength could still be large enough to increase the absolute value of r/sub sd/ = [Gamma(Z 0 → anti sd) - (s ↔ d)] Gamma/sub T/(Z 0 → quarks) by a factor of 360 over its Standard Model-predicted upper limit. The K/sub L/ 0 -K/sub s/ 0 mass difference Δm and K/sub L/ 0 -K/sub s/ 0 mixing parameter anti epsilon are used as input to determine the behavior of the tree-level s ↔ d multiplicative mixing parameter

  18. Study of the influence of the shell correction energy on the nuclear reactions leading to the region of the superheavy nuclei

    International Nuclear Information System (INIS)

    Marchix, A.

    2007-11-01

    The aim of this work is to study the influence of shell correction energy on the deexcitation of superheavy nuclei. For that purpose, a new statistical code, called Kewpie2, which is based on an original algorithm allowing to have access to very weak probabilities, was developed. The results obtained with Kewpie2 have been compared to the experimental data on residue cross sections obtained by cold fusion (Z=108 to Z=113) and by hot fusion (Z=112, Z=114 and Z=116), as well as data on fission times (Z=114, Z=120 and Z=126). Constraints on the microscopic structure of the studied nuclei have been obtained by means of the shell correction energy. By adjusting the intrinsic parameters of the models of fusion in order to reproduce the data on the fusion cross sections, this study shows the necessity of decreasing very strongly the shell correction energy predicted by the calculations of Moller and Nix, during the study of the residues cross sections as well for the nuclei produced by cold fusion as by hot fusion. On the other hand, during the confrontation of the results of Kewpie2 to the data on mean fission times, it is rather advisable to increase it. A shift of the proton shell closure predicted for Z=114 by the calculations of Moller and Nix towards larger Z would allow to explain these opposite conclusions. In this thesis, we also have shown the significant influence of the inclusion of isomeric states on fission times for the superheavy nuclei. (author)

  19. Trace elements in bivalves from the Rio Cruces, Chile, trace watershed evolution after a major earthquake and challenge a postulated chemical spill from a pulp plant

    Science.gov (United States)

    Risk, M.; Burchell, M.; Nairn, R.; Tubrett, M.; Forsterra, G.

    2009-05-01

    In May, 1960, the largest recorded earthquake in the history of the planet hit southern Chile, dropping part of the course of the Rio Cruces by 2m and creating an extensive wetland. The Brazilian Waterweed Egeria densa colonised the area, and became a primary food source for large populations of the Black-necked Swan, Cygnus melancoryphus. In 2004, a large pulp mill commenced operations upstream on the river. According to local reports, immediately after the opening of the plant, the weed died and the swans left. There was public outcry, and a search for a cause or a culprit. It was postulated that some sort of chemical spill from the plant caused the weed to die, resulting in departure of the swans. In 2008, we collected specimens of the bivalve Diplodon chilensis from several locations downstream from the Plant and towards the wetland to see if there was evidence of a chemical spill recorded in the shells. We prepared thin-sections of the shells to observe growth line development and patterns. Additionally, shell samples were analysed for stable oxygen isotopes and trace elements, using LA-ICP/MS. Based on annual growth lines, some of the bivalves were long-lived, with an age of more than 50 years. These individuals settled in the river shortly after the earthquake, and have lived there continuously ever since. Annual and sub-annual banding was clear, and the annual cyclicity of the major bands was verified with oxygen isotope analysis. There are no changes in growth corresponding to 2004. Trace element scans provided a wealth of information on the evolution of this earthquake-impacted wetland. Barium, Strontium and Manganese all showed strong annual cyclicity. From the analysis of older specimens, we interpret the high peaks of the Ba signal as reflecting soil erosion-Ba peaks are large immediately after the earthquake, then they diminish through time. Sr is likely a temperature signal, and Mn reflects runoff. Minor peaks in Cu, As and Pb probably reflect

  20. Standard elements; Elements standards

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    Following his own experience the author recalls the various advantages, especially in the laboratory, of having pre-fabricated vacuum-line components at his disposal. (author) [French] A la suite de sa propre experience, l'auteur veut rappeler les divers avantages que presente, tout particulierement en laboratoire, le fait d'avoir a sa disposition des elements pre-fabriques de canalisations a vide. (auteur)

  1. Os movimentos populares no Brasil: elementos sócio-históricos e desafios atuais * The popular movements in Brazil: elements historic social and current challenges

    Directory of Open Access Journals (Sweden)

    MICHELLY FERREIRA MONTEIRO ELIAS

    2014-12-01

    Full Text Available Resumo: Este artigo reflete sobre alguns desafios dos movimentos sociais de caráter popular no contexto atual da luta de classes no país. Consideram-se os movimentos populares como manifestações das lutas sociais que possuem determinações específicas de acordo com o movimento histórico. Diante das lutas que se configuraram da década de 1980 até os anos 2000, atualmente os desafios colocados para os movimentos populares estão permeados pela fragilidade do movimento operário; pela permanência da reestruturação produtiva e predominância do capital financeiro no contexto imperialista; pela continuidade de uma correlação de forças desfavoráveis para as lutas da classe trabalhadora e por uma conjuntura política caracterizada pelo Partido dos Trabalhadores (PT no comando do Governo Federal.Palavras-chave: lutas sociais; movimentos populares; realidade brasileira.Abstract: This article reflects about some challenges of social movements of popular character in the current context of class struggles in the country. Consider the popular movements as expressions of social struggles which have specific determinations in accordance with the historical movement. Faced of the struggles that have taken shape of the decade from 1980 until the year 2000, currently the challenges posed to the popular movements are permeated by the weakness of the labor movement; the permanence of productive restructuring and the predominance of financial capital in the context imperialist; by continuity of a correlation of forces unfavourable for the struggles of the working class and by a political situation characterized by the Partido dos Trabalhadores (PT in command of the Federal Government.Keywords: social struggles; populars movements; Brazilian reality.

  2. Superheavy dark matter

    CERN Document Server

    Riotto, Antonio

    2000-01-01

    It is usually thought that the present mass density of the Universe is dominated by a weakly interacting massive particle (WIMP), a fossil relic of the early Universe. Theoretical ideas and experimental efforts have focused mostly on production and detection of thermal relics, with mass typically in the range a few GeV to a hundred GeV. Here, we will review scenarios for production of nonthermal dark matter whose mass may be in the range 10/sup 12/ to 10/sup 19/ GeV, much larger than the mass of thermal wimpy WIMPS. We will also review recent related results in understanding the production of very heavy fermions through preheating after inflation. (19 refs).

  3. Structure effects in the region of superheavy elements via the alpha-decay chain of sup 2 sup 9 sup 3 118

    CERN Document Server

    Gupta, R K; Kumar, R; Balasubramaniam, M; Scheid, W

    2002-01-01

    The alpha-decay chain of sup 2 sup 9 sup 3 118, first proposed in the Berkeley cold fusion experiment sup 2 sup 0 sup 8 Pb( sup 8 sup 6 Kr, 1n) and now retracted, is calculated by using the preformed cluster model (PCM) of one of the authors (RKG). Also, the possible branchings of alpha-decays to heavier cluster decays of all the parents in this chain are calculated for the first time. The calculated Q-values, penetrabilities and preformation factors for alpha-decays suggest that the sup 2 sup 8 sup 5 114 nucleus with Z=114, N=171 is a magic nucleus, either due to the magicity of Z=114, or N=172 or both. The N=172 is proposed to be a magic number in certain relativistic mean-field calculations, but with Z 120. The calculated cluster decays point to new interesting possibilities of sup 1 sup 4 C decay of the sup 2 sup 8 sup 1 112 parent, giving rise to a (reasonably) deformed Z=106, N=161, sup 2 sup 6 sup 7 106 daughter (N=162 being now established as the deformed magic shell) or to a doubly magic sup 4 sup 8 ...

  4. Challenges for single molecule electronic devices with nanographene and organic molecules. Do single molecules offer potential as elements of electronic devices in the next generation?

    Science.gov (United States)

    Enoki, Toshiaki; Kiguchi, Manabu

    2018-03-01

    Interest in utilizing organic molecules to fabricate electronic materials has existed ever since organic (molecular) semiconductors were first discovered in the 1950s. Since then, scientists have devoted serious effort to the creation of various molecule-based electronic systems, such as molecular metals and molecular superconductors. Single-molecule electronics and the associated basic science have emerged over the past two decades and provided hope for the development of highly integrated molecule-based electronic devices in the future (after the Si-based technology era has ended). Here, nanographenes (nano-sized graphene) with atomically precise structures are among the most promising molecules that can be utilized for electronic/spintronic devices. To manipulate single small molecules for an electronic device, a single molecular junction has been developed. It is a powerful tool that allows even small molecules to be utilized. External electric, magnetic, chemical, and mechanical perturbations can change the physical and chemical properties of molecules in a way that is different from bulk materials. Therefore, the various functionalities of molecules, along with changes induced by external perturbations, allows us to create electronic devices that we cannot create using current top-down Si-based technology. Future challenges that involve the incorporation of condensed matter physics, quantum chemistry calculations, organic synthetic chemistry, and electronic device engineering are expected to open a new era in single-molecule device electronic technology.

  5. Galvanic element. Galvanisches Element

    Energy Technology Data Exchange (ETDEWEB)

    Sprengel, D.; Haelbig, H.

    1980-01-03

    The invention concerns a gas-tight sealed accumulator with positive and negative electrode plates and an auxillary electrode electroconductively bound to the latter for suppressing oxygen pressure. The auxillary electrode is an intermediate film electrode. The film catalysing oxygen reduction is hydrophilic in character and the other film is hydrophobic. A double coated foil has proved to be advantageous, the hydrophilic film being formed from polymer-bound activated carbon and the hydrophrobic film from porous polytetrafluoroethylene. A metallic network of silver or nickel is rolled into the outer side of the activated carbon film. This auxillary electrode can be used to advantage in all galvanic elements. Even primary cells fall within the scope of application for auxillary electrodes because many of these contain a highly oxidized electrodic material which tends to give off oxygen.

  6. Proceedings of the workshop on the nuclear sciences of the heaviest elements

    Energy Technology Data Exchange (ETDEWEB)

    Nagame, Yuichiro; Haba, Hiromitsu; Ikezoe, Hiroshi [eds.

    2000-03-01

    The workshop on the nuclear sciences of the heaviest elements took place on July 21-22, 1999 at the Japan Atomic Energy Research Institute (JAERI), Tokai. Approximately 40 scientists and 15 graduate students participated in the workshop which was organized by the Advanced Science Research Center, JAERI. The successful syntheses of three new super-heavy elements in 1999, Z=114 at the Joint Institute for Nuclear Research in Dubna, Russia, and Z=118 (with Z=116 following from {alpha}-decay of Z=118) at the Lawrence Berkeley National Laboratory (LBNL) in USA, are tremendous progress in the field of the heavy element research. The 1st International Conference on the Chemistry and Physics of the Transactinide Elements (TAN99) was held in Germany from September 26 to 30, 1999 to discuss in a larger context all scientific aspects of the heaviest elements. Thus, it was timely to hold the present domestic workshop to summarize what has been done in recent years, to see what has come true, and to discuss the perspectives in the near feature. The subjects in the workshop were classified into; (1) synthesis of heavy elements, (2) decay properties of heavy nuclei, (3) chemistry of the heaviest elements, and (4) future plans of the heavy element research in Japan. This volume contains the papers presented in the workshop. The 14 papers are indexed individually. (J.P.N.)

  7. The Synthesis and Decay Properties of the Heaviest Elements

    CERN Document Server

    Oganessian, Yu T

    2000-01-01

    The synthesis and the study of radioactive properties of new elements is considered with respect to the existence of the "islands of stability" of hypothetical superheavy elements predicted by the theory more than 35 years ago. Experimental data demonstrating an enhanced stability of nuclei in the vicinity of deformed shells with Z=108 and N=162 is discussed from the point of view of advent into more heavy and much more stable nuclides near the predicted spherical shells Z=114-122 and N=184 following after the doubly magic nucleus ^{208}Pb. The author presents the results of experiments on the synthesis of isotopes of elements 114 and 116 in the fusion reactions with ^{48}Ca. In these reactions the decay chains of heavy atoms consisting of sequential alpha-decays interrupted by spontaneous fission have been observed. The decay energies and probabilities are compared with predictions of different theoretical models describing the structure of heavy nuclei. The obtained results are considered as the first exper...

  8. Description of new element Z=113 and its α-decay chain

    International Nuclear Information System (INIS)

    Tai Fei; Chen Dinghan; Xu Chang; Ren Zhongzhou; National Laboratory of Heavy Ion Accelerator, Lanzhou

    2005-01-01

    RIKEN has produced a new element Z=113 by cold-fusion reaction. Here we systematically study the new nuclide 278 113 and its α-Decay chain using deformed relativistic mean-field theory with three sets of force parameters, TMA, NL-Z2 and NL3. The results are compared with those of the Skyrme-Hartree-Fock model, Moeller et al and also with the new experimental data. The experimental decay energies are well reproduced with RMF. This not only shows the validity of self-consistent field theoretical model in researching the ground state properties of superheavy nuclei, but also shows that prolate deformation is important for the ground state of these nuclei. (authors)

  9. Nuclear structure effects in quasifission – understanding the formation of the heaviest elements

    Directory of Open Access Journals (Sweden)

    Hinde D. J.

    2016-01-01

    Full Text Available Quasifission is an important process suppressing the fusion of two heavy nuclei in reactions used to create superheavy elements. Quasifission results in rapid separation of the dinuclear system initially formed at contact. Achieving reliable a priori prediction of quasifission probabilities is a very diffcult problem. Through measurements with projectiles from C to Ni, the Australian National University’s Heavy Ion Accelerator Facility and CUBE spectrometer have been used to map out mass-angle distributions (MAD - the fission mass-ratio as a function of centre-of-mass angle. These provide information on quasifission dynamics in the least modeldependent way. Average quasifission time-scales have been extracted, and compared with TDHF calculations of the collisions, with good agreement being found. With the baseline information from the survey of experimental MAD, strong influences of the nuclear structure of the projectile and target nuclei can be clearly determined.

  10. 48Ca+249Bk fusion reaction leading to element Z = 117: long-lived α-decaying 270Db and discovery of 266Lr.

    Science.gov (United States)

    Khuyagbaatar, J; Yakushev, A; Düllmann, Ch E; Ackermann, D; Andersson, L-L; Asai, M; Block, M; Boll, R A; Brand, H; Cox, D M; Dasgupta, M; Derkx, X; Di Nitto, A; Eberhardt, K; Even, J; Evers, M; Fahlander, C; Forsberg, U; Gates, J M; Gharibyan, N; Golubev, P; Gregorich, K E; Hamilton, J H; Hartmann, W; Herzberg, R-D; Heßberger, F P; Hinde, D J; Hoffmann, J; Hollinger, R; Hübner, A; Jäger, E; Kindler, B; Kratz, J V; Krier, J; Kurz, N; Laatiaoui, M; Lahiri, S; Lang, R; Lommel, B; Maiti, M; Miernik, K; Minami, S; Mistry, A; Mokry, C; Nitsche, H; Omtvedt, J P; Pang, G K; Papadakis, P; Renisch, D; Roberto, J; Rudolph, D; Runke, J; Rykaczewski, K P; Sarmiento, L G; Schädel, M; Schausten, B; Semchenkov, A; Shaughnessy, D A; Steinegger, P; Steiner, J; Tereshatov, E E; Thörle-Pospiech, P; Tinschert, K; Torres De Heidenreich, T; Trautmann, N; Türler, A; Uusitalo, J; Ward, D E; Wegrzecki, M; Wiehl, N; Van Cleve, S M; Yakusheva, V

    2014-05-02

    The superheavy element with atomic number Z=117 was produced as an evaporation residue in the (48)Ca+(249)Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allowed measuring decays of single atomic nuclei with half-lives between sub-μs and a few days. Two decay chains comprising seven α decays and a spontaneous fission each were identified and are assigned to the isotope (294)117 and its decay products. A hitherto unknown α-decay branch in (270)Db (Z = 105) was observed, which populated the new isotope (266)Lr (Z = 103). The identification of the long-lived (T(1/2) = 1.0(-0.4)(+1.9) h) α-emitter (270)Db marks an important step towards the observation of even more long-lived nuclei of superheavy elements located on an "island of stability."

  11. New functionalities in abundant element oxides: ubiquitous element strategy

    International Nuclear Information System (INIS)

    Hosono, Hideo; Hayashi, Katsuro; Kamiya, Toshio; Atou, Toshiyuki; Susaki, Tomofumi

    2011-01-01

    While most ceramics are composed of ubiquitous elements (the ten most abundant elements within the Earth's crust), many advanced materials are based on rare elements. A 'rare-element crisis' is approaching owing to the imbalance between the limited supply of rare elements and the increasing demand. Therefore, we propose a 'ubiquitous element strategy' for materials research, which aims to apply abundant elements in a variety of innovative applications. Creation of innovative oxide materials and devices based on conventional ceramics is one specific challenge. This review describes the concept of ubiquitous element strategy and gives some highlights of our recent research on the synthesis of electronic, thermionic and structural materials using ubiquitous elements. (topical review)

  12. Measurement of the first ionization potential of lawrencium, element 103.

    Science.gov (United States)

    Sato, T K; Asai, M; Borschevsky, A; Stora, T; Sato, N; Kaneya, Y; Tsukada, K; Düllmann, Ch E; Eberhardt, K; Eliav, E; Ichikawa, S; Kaldor, U; Kratz, J V; Miyashita, S; Nagame, Y; Ooe, K; Osa, A; Renisch, D; Runke, J; Schädel, M; Thörle-Pospiech, P; Toyoshima, A; Trautmann, N

    2015-04-09

    The chemical properties of an element are primarily governed by the configuration of electrons in the valence shell. Relativistic effects influence the electronic structure of heavy elements in the sixth row of the periodic table, and these effects increase dramatically in the seventh row--including the actinides--even affecting ground-state configurations. Atomic s and p1/2 orbitals are stabilized by relativistic effects, whereas p3/2, d and f orbitals are destabilized, so that ground-state configurations of heavy elements may differ from those of lighter elements in the same group. The first ionization potential (IP1) is a measure of the energy required to remove one valence electron from a neutral atom, and is an atomic property that reflects the outermost electronic configuration. Precise and accurate experimental determination of IP1 gives information on the binding energy of valence electrons, and also, therefore, on the degree of relativistic stabilization. However, such measurements are hampered by the difficulty in obtaining the heaviest elements on scales of more than one atom at a time. Here we report that the experimentally obtained IP1 of the heaviest actinide, lawrencium (Lr, atomic number 103), is 4.96(+0.08)(-0.07) electronvolts. The IP1 of Lr was measured with (256)Lr (half-life 27 seconds) using an efficient surface ion-source and a radioisotope detection system coupled to a mass separator. The measured IP1 is in excellent agreement with the value of 4.963(15) electronvolts predicted here by state-of-the-art relativistic calculations. The present work provides a reliable benchmark for theoretical calculations and also opens the way for IP1 measurements of superheavy elements (that is, transactinides) on an atom-at-a-time scale.

  13. Transplutonium elements

    Energy Technology Data Exchange (ETDEWEB)

    Sivaramakrishnan, C. K.; Jadhav, A. V.; Reghuraman, K.; Mathew, K. A.; Nair, P. S.; Ramaniah, M. V.

    1973-07-01

    Research progress is reported on studies of the transplutonium elements including recovery and purification of americium, preparation of /sup 238/Pu, extraction studies using diethylhexyl phosphate. (DHM)

  14. Transposable elements in cancer.

    Science.gov (United States)

    Burns, Kathleen H

    2017-07-01

    Transposable elements give rise to interspersed repeats, sequences that comprise most of our genomes. These mobile DNAs have been historically underappreciated - both because they have been presumed to be unimportant, and because their high copy number and variability pose unique technical challenges. Neither impediment now seems steadfast. Interest in the human mobilome has never been greater, and methods enabling its study are maturing at a fast pace. This Review describes the activity of transposable elements in human cancers, particularly long interspersed element-1 (LINE-1). LINE-1 sequences are self-propagating, protein-coding retrotransposons, and their activity results in somatically acquired insertions in cancer genomes. Altered expression of transposable elements and animation of genomic LINE-1 sequences appear to be hallmarks of cancer, and can be responsible for driving mutations in tumorigenesis.

  15. Toxic Elements

    DEFF Research Database (Denmark)

    Hajeb, Parvaneh; Shakibazadeh, Shahram; Sloth, Jens Jørgen

    2016-01-01

    Food is considered the main source of toxic element (arsenic, cadmium, lead, and mercury) exposure to humans, and they can cause major public health effects. In this chapter, we discuss the most important sources for toxic element in food and the foodstuffs which are significant contributors to h...

  16. How elements up to 118 were reached and how to go beyond

    Directory of Open Access Journals (Sweden)

    Düllmann Christoph E.

    2017-01-01

    Full Text Available The new superheavy elements with Z=113, 115, 117, and 118 were recently accepted into the periodic table and have been named. Elements with Z≥112 are predominantly produced in 48Ca-induced fusion reactions on actinide targets. This pathway is exhausted at Z=118 due to the lack of target materials with sufficiently high proton number to reach elements with Z≥119. Search experiments for yet heavier elements were performed at GSI Darmstadt and FLNR Dubna. The reactions 50Ti + 249Bk, which leads to Z=119, as well as 64Ni + 238U, 58Fe + 244Pu, 54Cr + 248Cm, and 50Ti + 249Cf, leading to Z=120, have been studied. Despite a total duration of these experiments of more than one year, neither succeeded in the identification of a new element. To obtain improved guidance for better-informed search experiments, nuclear reaction studies appear necessary and have recently started. Also technical advances will be an important pillar to this end. At GSI, work towards a new continuous-wave linear accelerator is ongoing and is briefly described.

  17. How elements up to 118 were reached and how to go beyond

    Science.gov (United States)

    Düllmann, Christoph E.

    2017-11-01

    The new superheavy elements with Z=113, 115, 117, and 118 were recently accepted into the periodic table and have been named. Elements with Z≥112 are predominantly produced in 48Ca-induced fusion reactions on actinide targets. This pathway is exhausted at Z=118 due to the lack of target materials with sufficiently high proton number to reach elements with Z≥119. Search experiments for yet heavier elements were performed at GSI Darmstadt and FLNR Dubna. The reactions 50Ti + 249Bk, which leads to Z=119, as well as 64Ni + 238U, 58Fe + 244Pu, 54Cr + 248Cm, and 50Ti + 249Cf, leading to Z=120, have been studied. Despite a total duration of these experiments of more than one year, neither succeeded in the identification of a new element. To obtain improved guidance for better-informed search experiments, nuclear reaction studies appear necessary and have recently started. Also technical advances will be an important pillar to this end. At GSI, work towards a new continuous-wave linear accelerator is ongoing and is briefly described.

  18. Perspectives of Super-Heavy Nuclei research with the upcoming separator-spectrometer setup S3 at GANIL/SPIRAL2 - The VAMOS Gas-Filled separator and AGATA

    Science.gov (United States)

    Theisen, Christophe

    2017-11-01

    Several facilities or apparatus for the synthesis and spectroscopy of the Super-Heavy Nuclei (SHN) are presently under construction in the world, which reflect the large interest for this region of extreme mass and charge, but also for the need of even more advanced research infrastructures. Among this new generation, the GANIL/SPIRAL2 facility in Caen, France, will soon deliver very high intense ion beams of several tens of particle μA. The Super Separator Spectrometer S3 has been designed to exploit these new beams for the study of SHN after separation. It will provide the needed beam rejection, mass selection and full arsenal of state-of-the art detection setups. Still at GANIL, the AGATA new generation gamma-ray tracking array is being operated. The VAMOS high acceptance spectrometer is being upgraded as a gas-filled separator. Its coupling with AGATA will lower the spectroscopic limits for the prompt gamma-ray studies of heavy and super-heavy nuclei. In this proceeding, these new devices will be presented along with a selected physics case.

  19. Fuel element

    International Nuclear Information System (INIS)

    Armijo, J.S.

    1976-01-01

    A fuel element for nuclear reactors is proposed which has a higher corrosion resisting quality in reactor operations. The zirconium alloy coating around the fuel element (uranium or plutonium compound) has on its inside a protection layer of metal which is metallurgically bound to the substance of the coating. As materials are namned: Alluminium, copper, niobium, stainless steel, and iron. This protective metallic layer has another inner layer, also metallurgically bound to its surface, which consists usually of a zirconium alloy. (UWI) [de

  20. MicroSISAK for the chemistry of the heaviest elements

    International Nuclear Information System (INIS)

    Hild, Daniel

    2012-01-01

    This thesis describes experiments with an apparatus called MicroSISAK which is able to perform liquid-liquid-extraction on a microliter-scale. Two immiscible liquids are mixed in a microstructured mixer unit and separated again via a Teflon membrane. In the first experiments, different extraction systems were explored for elements of the groups 4 and 7 of the periodic table. Their results were compared with those from batch experiments. The initial achieved extraction yields were insufficient for the envisaged experiments, for which reason different modifications were arranged to obtain improvements. With the aid of a heating element, which was connected to the MicroSISAK apparatus, one was able to rise the temperature for the extraction inside. This led to the expected increasing of the extraction yield. Furthermore the MikroSISAK apparatus was modified by the Institut fuer Mikrotechnik Mainz, which had developed and constructed this apparatus. The contact time of the two phases between the mixer and the separation unit was extended. This also led to an increased yield. Now the performance appeared to be sufficient to connect the apparatus to the TRIGAreactor Mainz to perform online-experiments. Fission products (technetium) produced in a nuclear reaction were guided to the MicroSISAK apparatus to separate them and to detect their decay in a γ-ray detector. Apart from the successful separations, the experiments also proved the functionality of a new degasser system and that an adequate detection system can be coupled to MicroSISAK. With this, the prerequisites for the vision of an application of MicroSISAK are realised: The investigation of the chemical properties of short-lived superheavy elements (SHE) at a heavy-ion accelerator. It is obvious to plan such an experiment for the heavy homolog of technetium, element 107, bohrium.

  1. Cognitive Challenges

    Science.gov (United States)

    ... Privacy Policy Sitemap Learn Engage Donate About TSC Cognitive Challenges Approximately 45% to 60% of individuals with TSC develop cognitive challenges (intellectual disabilities), although the degree of intellectual ...

  2. PELTIER ELEMENTS

    CERN Document Server

    Tani, Laurits

    2015-01-01

    To control Peltier elements, temperature controller was used. I used TEC-1091 that was manufactured my Meerstetter Engineering. To gain control with the temperature controller, software had to be intalled on a controlling PC. There were different modes to control the Peltier: Tempererature controller to control temperature, Static current/voltage to control voltage and current and LIVE ON/OFF to auto-tune the controller respectively to the system. Also, since near the collision pipe there is much radiation, radiation-proof Peltier elements have to be used. To gain the best results, I had to find the most efficient Peltier elements and try to get their cold side to -40 degrees Celsius.

  3. Study of the properties of the superheavy nuclei Z=117 produced in the 249Bk + 48Ca reaction

    International Nuclear Information System (INIS)

    Oganessian, Y.T.; Abdullin, F.S.; Dmitriev, S.N.; Itkis, M.G.; Polyakov, A.N.; Sagaidak, R.N.; Shirokovsky, I.V.; Shumeiko, M.V.; Subbotin, V.G.; Sukhov, A.M.; Tsyganov, Y.S.; Utyonkov, V.K.; Voinov, A.A.; Vostokin, G.K.; Alexander, C.; Binder, J.; Boll, R.A.; Ezold, J.; Felker, K.; Miernik, K.; Roberto, J.B.; Rykaczewski, K.P.; Gostic, J.M.; Henderson, R.A.; Moody, K.J.; Shaughnessy, D.H.; Stoyer, M.A.; Stoyer, N.J.; Grzywacz, R.K.; Miller, D.; Hamilton, J.H.; Ramayya, A.V.; Ryabinin, M.A.

    2014-01-01

    The reaction of 249 Bk with 48 Ca have been reinvestigated to provide new evidence for the discovery of element 117 on a larger number of events. The experiments were performed at five projectile energies and with a total beam dose of 48 Ca of about 4.6*10 19 . Two isotopes 293,294 117 were synthesized in the 249 Bk+ 48 Ca reaction, providing excitation functions and α-decay spectra of the produced isotopes that establishes these nuclei to be the products of the 4n- and 3n-evaporation channels, respectively. Decay properties of 293,294 117 and of all the daughter products agree with the data of the experiment in which these nuclei were synthesized for the first time in 2010. The new 289 115 events, populated by a decay of 293 117, demonstrate the same decay properties as those observed for 289 115 produced in the 243 Am( 48 Ca,2n) reaction thus providing cross-bombardment evidence. In addition, a single decay of 294 118 was observed from the reaction with 249 Cf - a result of the in-growth of 249 Cf in the 249 Bk target. (authors)

  4. Fuel element

    International Nuclear Information System (INIS)

    Kennedy, S.T.

    1982-01-01

    A nuclear reactor fuel element wherein a stack of nuclear fuel is prevented from displacement within its sheath by a retainer comprising a tube member which is radially expanded into frictional contact with the sheath by means of a captive ball within a tapered bore. (author)

  5. It's Elemental!

    Science.gov (United States)

    Diener, Lynn; Moore, John W.

    2011-01-01

    An understanding of the periodic table is central to the study of chemistry. So it is no surprise that it is included in the National Science Education Standards. But how can teachers get students excited about the periodic table? And how can teachers help them learn it in a way that challenges their critical-thinking skills? The authors'…

  6. Overcoming challenges

    Medline Plus

    Full Text Available ... breastfeeding Overcoming challenges Common questions about breastfeeding and pain Breastfeeding checklist: How to get a good latch Finding ... myths Overcoming challenges Common questions about breastfeeding and pain Breastfeeding checklist: How to get a good latch Finding ...

  7. Overcoming challenges

    Medline Plus

    Full Text Available ... section Back to section menu It's Only Natural Planning ahead Breastfeeding and baby basics Making breastfeeding work ... It's Only Natural Overcoming challenges It's Only Natural Planning ahead Addressing breastfeeding myths Overcoming challenges Common questions ...

  8. Radiographic element

    International Nuclear Information System (INIS)

    Abbott, T.I.; Jones, C.G.

    1984-01-01

    Radiographic elements are disclosed comprised of first and second silver halide emulsion layers separated by an interposed support capable of transmitting radiation to which the second image portion is responsive. At least the first imaging portion contains a silver halide emulsion in which thin tubular silver halide grains of intermediate aspect ratios (from 5:1 to 8:1) are present. Spectral sensitizing dye is adsorbed to the surface of the tubular grains. Increased photographic speeds can be realized at comparable levels of crossover. (author)

  9. Eleven new heaviest isotopes of elements Z=105 to Z=117 identified among the products of 249Bk+48Ca reactions

    International Nuclear Information System (INIS)

    Oganessian, Yu. Ts.; Abdullin, F. Sh.; Dmitriev, S. N.; Itkis, M. G.; Lobanov, Yu. V.; Mezentsev, A. N.; Polyakov, A. N.; Sagaidak, R. N.; Shirokovsky, I. V.; Subbotin, V. G.; Sukhov, A. M.; Tsyganov, Yu. S.; Utyonkov, V. K.; Voinov, A. A.; Vostokin, G. K.; Bailey, P. D.; Benker, D. E.; Ezold, J. G.; Porter, C. E.; Riley, F. D.

    2011-01-01

    The heaviest isotopes of elements Z=117 to Z=105, 294 117, 293 117, 290 115, 289 115, 286 113, 285 113, 282 Rg, 281 Rg, 278 Mt, 274 Bh, and 270 Db, were identified by means of the Dubna gas-filled recoil separator among the products of the 249 Bk + 48 Ca reaction. The details of the observed six decay chains, indicating the production and decay of isotopes 293 117 and 294 117, are presented and discussed. The decay energies and resulting half-lives of these new nuclei show a strong rise of stability with increasing neutron number, validating the concept of the island of enhanced stability for superheavy nuclei [Oganessian et al., Phys. Rev. Lett. 104, 142502 (2010)].

  10. Elements of quantum chromodynamics

    International Nuclear Information System (INIS)

    Bjorken, J.D.

    1979-01-01

    The subject of quantum chromodynamics is discussed at length. The introduction motivates the exposition and points out the analogies between QCD and QED. Then, after some assumptions about the nature of QCD, a description is given of what the solution of the theory should look like for three stages of complexity: pure QCD with no fermions or other sources, introduction of superheavy quarks, introduction of the light quarks (u, d, s) with vacuum polarization and pair creation. Next, canonical quantization of QCD by use of a Hamiltonian formulation (in A 0 = 0 gauge) is considered; gauge ambiguities, theta vacua, instantons, etc., are encountered. Then the properties of the three stages noted above are discussed in much greater detail. These follow descriptions of the confinement problem and various approaches to it, as well as of more radical alternatives to QCD, such as the string model or the Pati-Salam program. Included in the summary is an assessment of the current situation. 101 references, 23 figures, 2 tables

  11. Fuel element

    International Nuclear Information System (INIS)

    Hirose, Yasuo.

    1982-01-01

    Purpose: To increase the plenum space in a fuel element used for a liquid metal cooled reactor. Constitution: A fuel pellet is secured at one end with an end plug and at the other with a coil spring in a tubular container. A mechanism for fixing the coil spring composed of a tubular unit is mounted by friction with the inner surface of the tubular container. Accordingly, the recoiling force of the coil spring can be retained by fixing mechanism with a small volume, and since a large amount of plenum space can be obtained, the internal pressure rise in the cladding tube can be suppressed even if large quantities of fission products are discharged. (Kamimura, M.)

  12. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    The fission-like configurations are used for the total deformation energy calculations. A ... oscillator potential for the two fission fragment regions reads as ... Beyond this limit, the contribution of more remote levels is negligible. Once the density ...

  13. Chemistry aided nuclear physics studies

    NARCIS (Netherlands)

    Even, Julia

    2016-01-01

    Studies of the superheavy elements bring several challenges through low production yields, short half-lives, and high background rates. This paper describes the possibilities of chemical separations as techniques to overcome the background problematic and to investigate the nuclear properties of the

  14. Overcoming challenges

    Medline Plus

    Full Text Available ... Disease and Stroke HIV and AIDS Mental Health Pain Pregnancy Reproductive Health Sexual Health Sexually Transmitted Infections ... breastfeeding Overcoming challenges Common questions about breastfeeding and pain Breastfeeding checklist: How to get a good latch ...

  15. Overcoming challenges

    Medline Plus

    Full Text Available ... menu It's Only Natural Planning ahead Breastfeeding and baby basics Making breastfeeding work for you Addressing breastfeeding ... in the African-American community Incredible facts about babies, breastmilk, and breastfeeding Overcoming challenges Common questions about ...

  16. Overcoming challenges

    Medline Plus

    Full Text Available ... facts about babies, breastmilk, and breastfeeding Overcoming challenges Common questions about breastfeeding and pain Breastfeeding checklist: How to get a good latch Finding support It takes a village: Building ...

  17. Cognitive Challenges

    Science.gov (United States)

    ... Alliance Our Story Our Vision Our Team Our Leadership Our Results Our Corporate Policies FAQs Careers Contact Us Media Store Privacy Policy Sitemap Learn Engage Donate About TSC Cognitive Challenges Approximately 45% to 60% of individuals with TSC ...

  18. Overcoming challenges

    Medline Plus

    Full Text Available ... breastfeeding means to them. Subscribe To receive Breastfeeding email updates Enter email Submit Overcoming challenges Breastfeeding has a long list ... breastfeeding means to them. Subscribe To receive Breastfeeding email updates Enter email Submit All material contained on ...

  19. Overcoming challenges

    Medline Plus

    Full Text Available ... into your life Breastfeeding in daily life: At home and in public Laws that support breastfeeding 10 ... and jobs View all pages in this section Home It's Only Natural Overcoming challenges It's Only Natural ...

  20. Environmental challenge

    International Nuclear Information System (INIS)

    Conable, B.; Warford, J.; Partow, Z.; Lutz, E.; Munasinghe, M.

    1991-09-01

    The contents include the following: Development and the Environment: A Global Balance; Evolution of the World Bank's Environmental Policy; Accounting for the Environment; Public Policy and the Environment; Managing Drylands; Environmental Action Plans in Africa; Agroforestry in Sub-Saharan Africa; Irrigation and the Environmental Challenge; Curbing Pollution in Developing Countries; Global Warming and the Developing World; and The Global Environment Facility

  1. Challenging Identities

    DEFF Research Database (Denmark)

    depends on the conceptual or ideological constellation in which it takes part. This volume on one hand demonstrates the role of notions of identity in a variety of European contexts, and on the other hand highlights how there may be reasons to challenge the use of the term and corresponding social...

  2. Overcoming challenges

    Medline Plus

    Full Text Available ... Contact Us Blog Popular topics Vision and mission Leadership Programs and activities In your community Funding opportunities Internships and jobs View all pages in this section Home It's Only Natural Overcoming challenges It's Only Natural Planning ahead Addressing breastfeeding myths ...

  3. Overcoming challenges

    Medline Plus

    Full Text Available ... we are What we do Programs and activities Work with us Contact Us Blog Popular topics Vision and mission Leadership Programs and activities In your community Funding opportunities Internships and jobs View all pages in this section Home It's Only Natural Overcoming challenges It's Only Natural ...

  4. Steering committee for the management of the post-accidental phase of a nuclear accident or of a radiological situation (CODIRPA). Work group nr 4. Response to health challenges after a radiological accident - Stage report issue nr 2 of 2007 November 5; Synthesis of doctrinal elements and recommendations; Consultative meeting - February 2009; Final report March 2011; Report synthesis

    International Nuclear Information System (INIS)

    Bernier, Marie-Odile; Challeton-de Vathaire, Cecile; Catelinois, Olivier; Pirard, Philippe; Collignon, Albert; Corblet, Sibylle; Empereur Bissonnet, Pascal; Fite, Johanna; Mehl Auget, Isabelle; Fleutot, Jean-Baptiste; Gavel, Yves; Geis-Bonnemains, Nathalie; Geneau, Christian; Guagniere, Bertrand; Janin, Claire; Lang, Thierry; Marielle, Schmitt; N'Diaye, Bakhao; Raoul, Christophe; Ricoux, Christine; Schwoebel, Valerie; Telion, Caroline; Tillier, Claude; Verger, Pierre; Volant, Philippe

    2007-01-01

    A first report describes effects of radiological accidents on health, and possible scenarios (dose assessments, exposed population, health challenges), gives an overview of methods and arrangements used to count exposed populations and to assess received doses, and presents the foreseen reception centres. It describes the health management organisation (medical and psychological care of exposed population, public information), and reports an analysis of health risks associated with the accident. The next document contains a synthesis of doctrinal elements and recommendations regarding information acquisition, the management of health consequences of the accident, the assessment of the health impact. Propositions made by the work group to face health challenges are presented in a Power Point presentation. The final report addresses the context of preparation of the response to a radiological accident in France (studied accidents and scenarios, public health challenges), proposes a chronological synthesis of actions to be undertaken during a preparation phase, an emergency phase, a transition phase, and a long term phase), and a detailed presentation of main actions to be undertaken (medical and psychological care, reception centres, counting, health risk analysis, health information)

  5. Mobility Challenges

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lassen, Claus

    2011-01-01

    This article takes point of departure in the challenges to understand the importance of contemporary mobility. The approach advocated is a cross-disciplinary one drawing on sociology, geography, urban planning and design, and cultural studies. As such the perspective is to be seen as a part...... of the so-called ‘mobility turn’ within social science. The perspective is illustrative for the research efforts at the Centre for Mobility and Urban Studies (C-MUS), Aalborg University. The article presents the contours of a theoretical perspective meeting the challenges to research into contemporary urban...... mobilities. In particular the article discusses 1) the physical city, its infrastructures and technological hardware/software, 2) policies and planning strategies for urban mobility and 3) the lived everyday life in the city and the region....

  6. Challenges for Contextualizing Language Learning

    DEFF Research Database (Denmark)

    Eskildsen, Søren; Rehm, Matthias

    2013-01-01

    To help facilitate language learning for immigrants or foreigners arriving to another culture and language, we propose a context-aware mobile application. To expand on the known elements like location, activity, time and identity, we investigate the challenges on including cultural awareness to e...

  7. Global challenges

    International Nuclear Information System (INIS)

    Blix, H.

    1990-01-01

    A major challenge now facing the world is the supply of energy needed for growth and development in a manner which is not only economically viable but also environmentally acceptable and sustainable in view of the demands of and risks to future generations. The internationally most significant pollutants from energy production through fossil fuels are SO 2 and NO x which cause acid rain, and CO 2 which is the most significant contributor to the greenhouse effect. Nuclear power, now providing about 17% of the world's electricity and 5% of the primary energy already is making a notable contribution to avoiding these emissions. While the industrialized countries will need more energy and especially electricity in the future, the needs of the developing countries are naturally much larger and present a tremendous challenge to the shaping of the world's future energy supply system. The advanced countries will have to accept special responsibilities, as they can most easily use advanced technologies and they have been and remain the main contributors to the environmental problems we now face. Energy conservation and resort to new renewable energy sources, though highly desirable, appear inadequate alone to meet the challenges. The world can hardly afford to do without an increased use of nuclear power, although it is strongly contested in many countries. The objections raised against the nuclear option focus on safety, waste management and disposal problems and the risk for proliferation of nuclear weapons. These issues are not without their problems. The risk of proliferation exists but will not appreciably diminish with lesser global reliance on nuclear power. The waste issue is more of a political than a technical problem. The use of nuclear power, or any other energy source, will never be at zero risk, but the risks are constantly reduced by new techniques and practices. The IAEA sees it as one of its priority tasks to promote such techniques. (author)

  8. Discrete Element Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J; Johnson, S

    2007-12-03

    The Distinct Element Method (also frequently referred to as the Discrete Element Method) (DEM) is a Lagrangian numerical technique where the computational domain consists of discrete solid elements which interact via compliant contacts. This can be contrasted with Finite Element Methods where the computational domain is assumed to represent a continuum (although many modern implementations of the FEM can accommodate some Distinct Element capabilities). Often the terms Discrete Element Method and Distinct Element Method are used interchangeably in the literature, although Cundall and Hart (1992) suggested that Discrete Element Methods should be a more inclusive term covering Distinct Element Methods, Displacement Discontinuity Analysis and Modal Methods. In this work, DEM specifically refers to the Distinct Element Method, where the discrete elements interact via compliant contacts, in contrast with Displacement Discontinuity Analysis where the contacts are rigid and all compliance is taken up by the adjacent intact material.

  9. Data Challenges

    CERN Multimedia

    McCubbin, N A

    Some two years ago we planned a series of Data Challenges starting at the end of 2001. At the time, that seemed to be comfortingly far in the future... Well, as the saying goes, doesn't time fly when you are having fun! ATLAS Computing is now deep in the throes of getting the first Data Challenge (DC0) up and running. One of the main aims of DC0 is to have a software 'release' in which we can generate full physics events, track all particles through the detector, simulate the detector response, reconstruct the event, and study it, with appropriate data storage en route. As all software is "always 95% ready" (!), we have been able to do most of this, more or less, for some time. But DC0 forces us to have everything working, together, at the same time: a reality check. DC0 should finish early next year, and it will be followed almost immediately afterwards by DC1 (DC0 was foreseen as the 'check' for DC1). DC1 will last into the middle of 2002, and has two major goals. The first is generation, simulation, and r...

  10. Prefabricated elements and structures: Developments, tests and experiences

    DEFF Research Database (Denmark)

    Goltermann, Per

    2014-01-01

    Danish concrete structures are often built with prefabricated elements, joined together on the site and this provides a large challenge to constantly improve and optimize the elements, the joints and the models. DTU Byg has been active in the development, testing and modelling of new elements...

  11. Challenging makerspaces

    DEFF Research Database (Denmark)

    Sandvik, Kjetil; Thestrup, Klaus

    This paper takes its departure in the EU-project MakEY - Makerspaces in the early years – enhancing digital literacy and creativity that is part of a H2020 RISE-program and is running January 2017 - June 2019. Here digital literacy and creative skills of young children between the age of 3......-8 will be developed through participation in creative activities in specially-designed spaces termed ‘makerspaces’. This paper discusses, develops and challenges this term in relation to Danish pedagogical traditions, to expanding makerspaces onto the internet and on how to combine narratives and construction....... The Danish part of the project will be undertaken by a small network of partners: DOKK1, a public library and open urban space in Aarhus, that is experimenting with different kind of makerspaces, spaces and encounters between people, The LEGO-LAB situated at Computer Science, Aarhus University, that has...

  12. Chemistry of the elements

    International Nuclear Information System (INIS)

    Greenwood, N.N.; Earnshaw, A.

    1984-01-01

    This textbook presents an account of the chemistry of the elements for both undergraduate and postgraduate students. It covers not only the 'inorganic' chemistry of the elements, but also analytical, theoretical, industrial, organometallic;, bio-inorganic and other areas of chemistry which apply. The following elements of special nuclear interest are included: Rb, Cs, Fr, Sr, Ba, Ra, Po, At, Rn, Sc, Y, Zr, Hf, V, Nb, Ta, Mo, Tc, Ru, the Lanthanide Elements, the Actinide Elements. (U.K.)

  13. Homeland Security. Management Challenges Facing Federal Leadership

    Science.gov (United States)

    2002-12-01

    Security Management Challenges Facing Federal Leadership 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT...including attention to management practices and key success factors. HOMELAND SECURITY Management Challenges Facing Federal Leadership www.gao.gov/cgi...significant management and coordination challenges if it is to provide this leadership and be successful in preventing and responding to any future

  14. Glomar challenger

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, J P

    1969-01-01

    The Glomar Challenger has a length of 400 ft, a 65-ft beam, and a depth of 27 ft 6-in. She has a draft of 20 ft with a gross displacement of 10,500 long tons. The principal specifications of the vessel are tabulated. To achieve dynamic positioning, 4 fixed thrusters and the vessel's 2 propulsion screws are utilized. The ''fix'' is obtained by placing a sonar beacon, with self contained batteries, on the ocean floor at a selected site. The vessel is provided with 4 hydrophones installed in the hull at the 4 corners of a square. The sonar beacon radiates sound waves at a fixed pulse rate. If the vessel is directly over the beacon, the sound waves will arrive at all hydrophones simultaneously. A difference in time of arrival indicates the vessel is off location. The sound signals received by the hydrophones are fed into a computer. They are changed into coordinate information, which serves as the primary function of determining corrective action by the vessel's propulsion and thruster system. The computer feeds back information into a control system, which enables the propulsion and thrusters to automatically respond, in order to keep the vessel on the predetermined location. The major drilling components are listed. The deep-sea drilling project is described. A summary of the first leg is given in tabular form.

  15. Scrapheap Challenge

    CERN Document Server

    2004-01-01

    Three British guys at CERN recently took a break from work to try their hand at Scrapheap Challenge. Shown on Channel 4 in the UK, it is a show where two teams must construct a machine for a specific task using only the junk they can scavenge from the scrap yard around them. And they have just 10 hours to build their contraption before it is put to the test. The first round, aired 19 September, pitted a team of three women, from the British Army's Royal Electrical and Mechanical Engineers, against the CERN guys - the Up 'n Atoms: Ali Day, David McFarlane and James Ridewood. Each team, with the help of an appointed expert, had the task of making a giant, 3-metre self-propelled "bowling ball", to roll down a 50 metre bowling alley at skittles 4 metres high. The Up 'n Atoms' contraption featured a small car with a huge wheel on its back. Once up to speed, slamming on the brakes caused the wheel to roll over and take the car with it. On their very last run they managed to take out seven pins. Luckily, though, ...

  16. Ecological Challenges for Closed Systems

    Science.gov (United States)

    Nelson, Mark; Dempster, William; Allen, John P.

    2012-07-01

    Closed ecological systems are desirable for a number of purposes. In space life support systems, material closure allows precious life-supporting resources to be kept inside and recycled. Closure in small biospheric systems facilitates detailed measurement of global ecological processes and biogeochemical cycles. Closed testbeds facilitate research topics which require isolation from the outside (e.g. genetically modified organisms; radioisotopes) so their ecological interactions and fluxes can be studied separate from interactions with the outside environment. But to achieve and maintain closure entails solving complex ecological challenges. These challenges include being able to handle faster cycling rates and accentuated daily and seasonal fluxes of critical life elements such as carbon dioxide, oxygen, water, macro- and mico-nutrients. The problems of achieving sustainability in closed systems for life support include how to handle atmospheric dynamics including trace gases, producing a complete human diet and recycling nutrients and maintaining soil fertility, the sustaining of healthy air and water and preventing the loss of crucial elements from active circulation. In biospheric facilities the challenge is also to produce analogues to natural biomes and ecosystems, studying processes of self-organization and adaptation in systems that allow specification or determination of state variables and cycles which may be followed through all interactions from atmosphere to soils. Other challenges include the dynamics and genetics of small populations, the psychological challenges for small isolated human groups and measures and options which may be necessary to ensure long-term operation of closed ecological systems.

  17. Regulatory challenges

    International Nuclear Information System (INIS)

    Austvik, Ole Gunnar

    2003-01-01

    The problem for policy makers wanting to liberalize natural gas markets is that its concentrated structure may also be the socially most efficient one. Because of scale economies, more firms operating in the market may incur higher transportation costs unless the market grows sufficiently in each geographic segment. This argument goes for product extension through vertical (or horizontal) integration and the exploitation of economies of scope as well. Thus, the challenge for governments is to intervene in a way that preserves a market structure that has the potential to minimize cost, and at the same lime change its behavior in order to avoid possible lax cost control and exploitation of market power. The existence of scope advantages indicates that liberalization of the market should open for the possibility to bundle services in competition with provision of unbundled services. If operations are unbundled and there exist economies of scope, the gain from increased competition should be weighed against the losses of less efficient operations of each firm. Thus, with the growth in the European market, gradually more arguments support the idea of unbundling. The significant scale economy in trunk pipelines, sunk investments and capital immobility, possible economies of scope in vertical integration and companies' bundling of services influences vertical and horizontal ownership relations and contractual terms in the European gas market. In specific segments of the markets, these relationships may promote efficient investments and pricing without public interference, but the strong concentration of market power indicates that this is rather the exception than the rule. In order to design an efficient and welfare maximizing way of regulating the market one needs a closer identification of the actual goal of the regulation. Microeconomic theory is often used for this purpose. The author discusses the alternatives of laissez-faire, nationalization or regulation for the

  18. Sub-barrier quasifission in heavy element formation reactions with deformed actinide target nuclei

    Science.gov (United States)

    Hinde, D. J.; Jeung, D. Y.; Prasad, E.; Wakhle, A.; Dasgupta, M.; Evers, M.; Luong, D. H.; du Rietz, R.; Simenel, C.; Simpson, E. C.; Williams, E.

    2018-02-01

    Background: The formation of superheavy elements (SHEs) by fusion of two massive nuclei is severely inhibited by the competing quasifission process. Low excitation energies favor SHE survival against fusion-fission competition. In "cold" fusion with spherical target nuclei near 208Pb, SHE yields are largest at beam energies significantly below the average capture barrier. In "hot" fusion with statically deformed actinide nuclei, this is not the case. Here the elongated deformation-aligned configurations in sub-barrier capture reactions inhibits fusion (formation of a compact compound nucleus), instead favoring rapid reseparation through quasifission. Purpose: To determine the probabilities of fast and slow quasifission in reactions with prolate statically deformed actinide nuclei, through measurement and quantitative analysis of the dependence of quasifission characteristics at beam energies spanning the average capture barrier energy. Methods: The Australian National University Heavy Ion Accelerator Facility and CUBE fission spectrometer have been used to measure fission and quasifission mass and angle distributions for reactions with projectiles from C to S, bombarding Th and U target nuclei. Results: Mass-asymmetric quasifission occurring on a fast time scale, associated with collisions with the tips of the prolate actinide nuclei, shows a rapid increase in probability with increasing projectile charge, the transition being centered around projectile atomic number ZP=14 . For mass-symmetric fission events, deviations of angular anisotropies from expectations for fusion fission, indicating a component of slower quasifission, suggest a similar transition, but centered around ZP˜8 . Conclusions: Collisions with the tips of statically deformed prolate actinide nuclei show evidence for two distinct quasifission processes of different time scales. Their probabilities both increase rapidly with the projectile charge. The probability of fusion can be severely

  19. Data Element Registry Services

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data Element Registry Services (DERS) is a resource for information about value lists (aka code sets / pick lists), data dictionaries, data elements, and EPA data...

  20. Basic Finite Element Method

    International Nuclear Information System (INIS)

    Lee, Byeong Hae

    1992-02-01

    This book gives descriptions of basic finite element method, which includes basic finite element method and data, black box, writing of data, definition of VECTOR, definition of matrix, matrix and multiplication of matrix, addition of matrix, and unit matrix, conception of hardness matrix like spring power and displacement, governed equation of an elastic body, finite element method, Fortran method and programming such as composition of computer, order of programming and data card and Fortran card, finite element program and application of nonelastic problem.

  1. Radiolabelled cellular blood elements

    International Nuclear Information System (INIS)

    Sinzinger, H.

    1990-01-01

    This book reports on radiolabelled cellular blood elements, covering new advances made during the past several years, in particular the use of Tc-99 as a tracer for blood elements. Coverage extends to several radiolabelled monoclonal antibodies that are specific for blood components and may label blood elements in vivo

  2. The Challenge of the bespoke

    DEFF Research Database (Denmark)

    Tamke, Martin; Quinn, Gregory; Evers, Henrik Leander

    2014-01-01

    The Dermoid project, a series of three plywood grid shells, navigates at the interface between parametrically designed architectural spaces and the efficiency and resourcefulness of the simulations that are necessary in order to build them. It highlights the increasingly common challenges...... and conflicts which occur in building practice ranging from design to fabrication and highlights approaches that facilitate implementation in multiple scales of material, element and structure....

  3. ATLAS Data Challenge 1

    CERN Document Server

    Poulard, G

    2003-01-01

    In 2002 the ATLAS experiment started a series of Data Challenges (DC) of which the goals are the validation of the Computing Model, of the complete software suite, of the data model, and to ensure the correctness of the technical choices to be made. A major feature of the first Data Challenge (DC1) was the preparation and the deployment of the software required for the production of large event samples for the High Level Trigger (HLT) and physics communities, and the production of those samples as a world-wide distributed activity. The first phase of DC1 was run during summer 2002, and involved 39 institutes in 18 countries. More than 10 million physics events and 30 million single particle events were fully simulated. Over a period of about 40 calendar days 71000 CPU-days were used producing 30 Tbytes of data in about 35000 partitions. In the second phase the next processing step was performed with the participation of 56 institutes in 21 countries (~ 4000 processors used in parallel). The basic elements of ...

  4. Rare (Earth Elements [score

    Directory of Open Access Journals (Sweden)

    Camilo Méndez

    2014-12-01

    Full Text Available Rare (Earth Elements is a cycle of works for solo piano. The cycle was inspired by James Dillon’s Book of Elements (Vol. I-V. The complete cycle will consist of 14 pieces; one for each selected rare (earth element. The chosen elements are Neodymium, Erbium, Tellurium, Hafnium, Tantalum, Technetium, Indium, Dysprosium, Lanthanium, Cerium, Europium, Terbium, Yttrium and Darmstadtium. These elements were selected due to their special atomic properties that in many cases make them extremely valuable for the development of new technologies, and also because of their scarcity. To date, only 4 works have been completed Yttrium, Technetium, Indium and Tellurium.

  5. Generalized finite elements

    International Nuclear Information System (INIS)

    Wachspress, E.

    2009-01-01

    Triangles and rectangles are the ubiquitous elements in finite element studies. Only these elements admit polynomial basis functions. Rational functions provide a basis for elements having any number of straight and curved sides. Numerical complexities initially associated with rational bases precluded extensive use. Recent analysis has reduced these difficulties and programs have been written to illustrate effectiveness. Although incorporation in major finite element software requires considerable effort, there are advantages in some applications which warrant implementation. An outline of the basic theory and of recent innovations is presented here. (authors)

  6. The elements of life and medicines.

    Science.gov (United States)

    Chellan, Prinessa; Sadler, Peter J

    2015-03-13

    Which elements are essential for human life? Here we make an element-by-element journey through the periodic table and attempt to assess whether elements are essential or not, and if they are, whether there is a relevant code for them in the human genome. There are many difficulties such as the human biochemistry of several so-called essential elements is not well understood, and it is not clear how we should classify elements that are involved in the destruction of invading microorganisms, or elements which are essential for microorganisms with which we live in symbiosis. In general, genes do not code for the elements themselves, but for specific chemical species, i.e. for the element, its oxidation state, type and number of coordinated ligands, and the coordination geometry. Today, the biological periodic table is in a position somewhat similar to Mendeleev's chemical periodic table of 1869: there are gaps and we need to do more research to fill them. The periodic table also offers potential for novel therapeutic and diagnostic agents, based on not only essential elements, but also non-essential elements, and on radionuclides. Although the potential for inorganic chemistry in medicine was realized more than 2000 years ago, this area of research is still in its infancy. Future advances in the design of inorganic drugs require more knowledge of their mechanism of action, including target sites and metabolism. Temporal speciation of elements in their biological environments at the atomic level is a major challenge, for which new methods are urgently needed.

  7. Limitless Analytic Elements

    Science.gov (United States)

    Strack, O. D. L.

    2018-02-01

    We present equations for new limitless analytic line elements. These elements possess a virtually unlimited number of degrees of freedom. We apply these new limitless analytic elements to head-specified boundaries and to problems with inhomogeneities in hydraulic conductivity. Applications of these new analytic elements to practical problems involving head-specified boundaries require the solution of a very large number of equations. To make the new elements useful in practice, an efficient iterative scheme is required. We present an improved version of the scheme presented by Bandilla et al. (2007), based on the application of Cauchy integrals. The limitless analytic elements are useful when modeling strings of elements, rivers for example, where local conditions are difficult to model, e.g., when a well is close to a river. The solution of such problems is facilitated by increasing the order of the elements to obtain a good solution. This makes it unnecessary to resort to dividing the element in question into many smaller elements to obtain a satisfactory solution.

  8. The solar element

    DEFF Research Database (Denmark)

    Kragh, Helge

    2009-01-01

    of the nineteenth century. In the modest form of a yellow spectral line known as D3, 'helium' was sometimes supposed to exist in the Sun's atmosphere, an idea which is traditionally ascribed to J. Norman Lockyer. Did Lockyer discover helium as a solar element? How was the suggestion received by chemists, physicists...... and astronomers in the period until the spring of 1895, when William Ramsay serendipitously found the gas in uranium minerals? The hypothetical element helium was fairly well known, yet Ramsay's discovery owed little or nothing to Lockyer's solar element. Indeed, for a brief while it was thought that the two...... elements might be different. The complex story of how helium became established as both a solar and terrestrial element involves precise observations as well as airy speculations. It is a story that is unique among the discovery histories of the chemical elements....

  9. The synthetic elements

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, D.C.

    1990-05-01

    Prior to 1940, the heaviest element known was uranium, discovered in 1789. Since that time the elements 93 through 109 have been synthesized and identified and the elements 43, 61, 85, and 87 which were missing form the periodic tables of the 1930's have been discovered. The techniques and problems involved in these discoveries and the placement of the transuranium elements in the periodic table will be discussed. The production and positive identification of elements heavier than Md (Z=101), which have very short half-lives and can only be produced an atom-at-a-time, are very difficult and there have been controversies concerning their discovery. Some of the new methods which have been developed and used in these studies will be described. The prospects for production of still heavier elements will be considered.

  10. The synthetic elements

    International Nuclear Information System (INIS)

    Hoffman, D.C.

    1990-05-01

    Prior to 1940, the heaviest element known was uranium, discovered in 1789. Since that time the elements 93 through 109 have been synthesized and identified and the elements 43, 61, 85, and 87 which were missing form the periodic tables of the 1930's have been discovered. The techniques and problems involved in these discoveries and the placement of the transuranium elements in the periodic table will be discussed. The production and positive identification of elements heavier than Md (Z=101), which have very short half-lives and can only be produced an atom-at-a-time, are very difficult and there have been controversies concerning their discovery. Some of the new methods which have been developed and used in these studies will be described. The prospects for production of still heavier elements will be considered

  11. Fuel element loading system

    International Nuclear Information System (INIS)

    Arya, S.P; s.

    1978-01-01

    A nuclear fuel element loading system is described which conveys a plurality of fuel rods to longitudinal passages in fuel elements. Conveyor means successively position the fuel rods above the longitudinal passages in axial alignment therewith and adapter means guide the fuel rods from the conveyor means into the longitudinal passages. The fuel elements are vibrated to cause the fuel rods to fall into the longitudinal passages through the adapter means

  12. Elements in biological AMS

    International Nuclear Information System (INIS)

    Vogel, J.S.; McAninch, J.; Freeman, S.

    1996-08-01

    AMS (Accelerator Mass Spectrometry) provides high detection sensitivity for isotopes whose half-lives are between 10 years and 100 million years. 14 C is the most developed of such isotopes and is used in tracing natural and anthropogenic organic compounds in the Earth's biosphere. Thirty-three elements in the main periodic table and 17 lanthanides or actinides have long lived isotopes, providing potential tracers for research in elemental biochemistry. Overlap of biologically interesting heavy elements and possible AMS tracers is discussed

  13. Analogs for transuranic elements

    International Nuclear Information System (INIS)

    Weimer, W.C.; Laul, J.C.; Kutt, J.C.

    1981-01-01

    A combined theoretical and experimental approach is being used to estimate the long-term environmental and biogeochemical behaviors of selected transuranic elements. The objective of this research is to estimate the effect that long-term (hundreds of years) environmental weathering has on the behavior of the transuranic elements americium and curium. This is achieved by investigating the actual behavior of naturally occurring rare earth elements, especially neodymium, that serve as transuranic analogs. Determination of the analog element behavior provides data that can be used to estimate the ultimate availability to man of transuranic materials released into the environment

  14. Seagrass leaf element content

    NARCIS (Netherlands)

    Vonk, J.A.; Smulders, Fee O.H.; Christianen, Marjolijn J.A.; Govers, Laura L.

    2017-01-01

    Knowledge on the role of seagrass leaf elements and in particular micronutrients and their ranges is limited. We present a global database, consisting of 1126 unique leaf values for ten elements, obtained from literature and unpublished data, spanning 25 different seagrass species from 28 countries.

  15. Berkeley new element program

    International Nuclear Information System (INIS)

    Ghiorso, A.

    1975-09-01

    The work done with element 106 is reviewed, and a new experiment which bears on the properties of the isotope of mass 260 with atomic number 104 is discussed. It is noted that in the case of element 106 a link is demonstrated to the granddaughter as well as the daughter

  16. Elemental Food for Thought

    Science.gov (United States)

    Cady, Susan

    2005-01-01

    One of the first tasks students learn in chemistry is to pronounce and spell the names of elements and learn their corresponding chemical symbols. Repetitive oral recitation is commonly used to learn this information, but games and puzzles can make this task creative, variable, and fun. Elemental Food for Thought is a puzzlelike activity that…

  17. Nuclear fuel element

    International Nuclear Information System (INIS)

    Mogard, J.H.

    1977-01-01

    A nuclear fuel element is disclosed for use in power producing nuclear reactors, comprising a plurality of axially aligned ceramic cylindrical fuel bodies of the sintered type, and a cladding tube of metal or metal alloys, wherein said cladding tube on its cylindrical inner surface is provided with a plurality of slightly protruding spacing elements distributed over said inner surface

  18. Proceedings of transuranium elements

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    The identification of the first synthetic elements was established by chemical evidence. Conclusive proof of the synthesis of the first artificial element, technetium, was published in 1937 by Perrier and Segre. An essential aspect of their achievement was the prediction of the chemical properties of element 43, which had been missing from the periodic table and which was expected to have properties similar to those of manganese and rhenium. The discovery of other artificial elements, astatine and francium, was facilitated in 1939-1940 by the prediction of their chemical properties. A little more than 50 years ago, in the spring of 1940, Edwin McMillan and Philip Abelson synthesized element 93, neptunium, and confirmed its uniqueness by chemical means. On August 30, 1940, Glenn Seaborg, Arthur Wahl, and the late Joseph Kennedy began their neutron irradiations of uranium nitrate hexahydrate. A few months later they synthesized element 94, later named plutonium, by observing the alpha particles emitted from uranium oxide targets that had been bombarded with deuterons. Shortly thereafter they proved that is was the second transuranium element by establishing its unique oxidation-reduction behavior. The symposium honored the scientists and engineers whose vision and dedication led to the discovery of the transuranium elements and to the understanding of the influence of 5f electrons on their electronic structure and bonding. This volume represents a record of papers presented at the symposium

  19. Matching Element Symbols with State Abbreviations: A Fun Activity for Browsing the Periodic Table of Chemical Elements

    Science.gov (United States)

    Woelk, Klaus

    2009-01-01

    A classroom activity is presented in which students are challenged to find matches between the United States two-letter postal abbreviations for states and chemical element symbols. The activity aims to lessen negative apprehensions students might have when the periodic table of the elements with its more than 100 combinations of letters is first…

  20. Study of the influence of the shell correction energy on the nuclear reactions leading to the region of the superheavy nuclei; Etude de l'influence de l'energie de correction de couches sur les reactions nucleaires menant a la region des noyaux superlourds

    Energy Technology Data Exchange (ETDEWEB)

    Marchix, A

    2007-11-15

    The aim of this work is to study the influence of shell correction energy on the deexcitation of superheavy nuclei. For that purpose, a new statistical code, called Kewpie2, which is based on an original algorithm allowing to have access to very weak probabilities, was developed. The results obtained with Kewpie2 have been compared to the experimental data on residue cross sections obtained by cold fusion (Z=108 to Z=113) and by hot fusion (Z=112, Z=114 and Z=116), as well as data on fission times (Z=114, Z=120 and Z=126). Constraints on the microscopic structure of the studied nuclei have been obtained by means of the shell correction energy. By adjusting the intrinsic parameters of the models of fusion in order to reproduce the data on the fusion cross sections, this study shows the necessity of decreasing very strongly the shell correction energy predicted by the calculations of Moller and Nix, during the study of the residues cross sections as well for the nuclei produced by cold fusion as by hot fusion. On the other hand, during the confrontation of the results of Kewpie2 to the data on mean fission times, it is rather advisable to increase it. A shift of the proton shell closure predicted for Z=114 by the calculations of Moller and Nix towards larger Z would allow to explain these opposite conclusions. In this thesis, we also have shown the significant influence of the inclusion of isomeric states on fission times for the superheavy nuclei. (author)

  1. Challenges of nuclear fusion

    International Nuclear Information System (INIS)

    Kunkel, W.B.

    1987-01-01

    After 30 years of research and development in many countries, the magnetic confinement fusion experiments finally seem to be getting close to the original first goal: the point of ''scientific break-even''. Plans are being made for a generation of experiments and tests with actual controlled thermonuclear fusion conditions. Therefore engineers and material scientists are hard at work to develop the required technology. In this paper the principal elements of a generic fusion reactor are described briefly to introduce the reader to the nature of the problems at hand. The main portion of the presentation summarises the recent advances made in this field and discusses the major issues that still need to be addressed in regard to materials and technology for fusion power. Specific examples are the problems of the first wall and other components that come into direct contact with the plasma, where both lifetime and plasma contamination are matters of concern. Equally challenging are the demands on structural materials and on the magnetic-field coils, particularly in connection with the neutron-radiation environment of fusion reactors. Finally, the role of ceramics must be considered, both for insulators and for fuel breeding purposes. It is evident that we still have a formidable task before us, but at this point none of the problems seem to be insoluble. (author)

  2. Challenges in Astronomy Education

    Science.gov (United States)

    De Greve, Jean-Pierre

    2010-11-01

    Astronomy is an attractive subject for education. It deals with fascination of the unknown and the unreachable, yet is uses tools, concepts and insights from various fundamental sciences such as mathematics, physics, chemistry, biology. Because of this it can be well used for introducing sciences to young people and to raise their interest in further studies in that direction. It is also an interesting subject for teaching as its different aspects (observation techniques, theory, data sampling and analysis, modelling,?) offer various didactical approaches towards different levels of pupils, students and different backgrounds. And it gives great opportunities to teach and demonstrate the essence of scientific research, through tutorials and projects. In this paper we discuss some of the challenges education in general, and astronomy in particular, faces in the coming decades, given the major geophysical and technological changes that can be deducted from our present knowledge. This defines a general, but very important background in terms of educational needs at various levels, and in geographical distribution of future efforts of the astronomical community. Special emphasis will be given to creative approaches to teaching, to strategies that are successful (such as the use of tutorials with element from computer games), and to initiatives complementary to the regular educational system. The programs developed by the IAU will be briefly highlighted.

  3. Nuclear fuel element

    International Nuclear Information System (INIS)

    Grossman, L.N.; Levin, H.A.

    1975-01-01

    A nuclear fuel element has disposed therein an alloy having the essential components of nickel, titanium and zirconium, and the alloy reacts with water, water vapor and reactive gases at reactor ambient temperatures. The alloy is disposed in the plenum of the fuel element in the form of particles in a hollow gas permeable container having a multiplicity of openings of size smallr than the size of the particles. The container is preferably held in the spring in the plenum of the fuel element. (E.C.B.)

  4. Elemental diffusion in stars

    International Nuclear Information System (INIS)

    Michaud, Georges; Montmerle, Thierry

    1977-01-01

    This paper is dealing with the origin of the elements in the universe. The scheme of nucleosynthesis is kept to explain the stellar generation of helium, carbon, etc... from the initial hydrogen; but a nonlinear theory is then elaborated to account for the anomalous abundances which were observed. The chemical elements would diffuse throughout the outer layers of a star under the action of the opposite forces of gravitation and radiation. This theory, with completing the nucleosynthesis, would contribute to give a consistent scheme of the elemental origin and abundances [fr

  5. Addressing the workforce pipeline challenge

    Energy Technology Data Exchange (ETDEWEB)

    Leonard Bond; Kevin Kostelnik; Richard Holman

    2006-11-01

    A secure and affordable energy supply is essential for achieving U.S. national security, in continuing U.S. prosperity and in laying the foundations to enable future economic growth. To meet this goal the next generation energy workforce in the U.S., in particular those needed to support instrumentation, controls and advanced operations and maintenance, is a critical element. The workforce is aging and a new workforce pipeline, to support both current generation and new build has yet to be established. The paper reviews the challenges and some actions being taken to address this need.

  6. Bridge element deterioration rates.

    Science.gov (United States)

    2008-10-01

    This report describes the development of bridge element deterioration rates using the NYSDOT : bridge inspection database using Markov chains and Weibull-based approaches. It is observed : that Weibull-based approach is more reliable for developing b...

  7. 2. Transuranic elements

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    Methods of sample collection, sample storage, sample procedures and radioanalytical procedures for transuranic elements in marine environment are reviewed and recommended. Alpha spectrometry and scintillation techniques are used for measurement of isotopic content. Separation processes for samples are described

  8. Heavy element research

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Heavy element research activities in metallurgy and ceramics during 1976 at Lawrence Berkeley Laboratory are reviewed. Topics include: microstructure, properties and alloy design; ceramic alloy program; high resolution and high voltage electron microscopy; and powder metallurgy

  9. Nuclear reactor fuel elements

    International Nuclear Information System (INIS)

    Hindle, E.D.

    1981-01-01

    An array of rods comprising zirconium alloy sheathed nuclear fuel pellets assembled to form a fuel element for a pressurised water reactor is claimed. The helium gas pressure within each rod differs substantially from that of its closest neighbours

  10. Nuclear reactor fuel elements

    International Nuclear Information System (INIS)

    Hindle, E.D.

    1984-01-01

    The fuel elements for a pressurised water reactor comprise arrays of rods of zirconium alloy sheathed nuclear fuel pellets. The helium gas pressure within each rod differs substantially from that of its closest neighbours

  11. Divergent picornavirus IRES elements

    DEFF Research Database (Denmark)

    Belsham, Graham

    2009-01-01

    Internal ribosome entry site (IRES) elements were first identified about 20 years ago within the 5' untranslated region of picornavirus RNAs. They direct a cap-independent mechanism of translation initiation on the viral RNA. Within the picornavirus family it is now known that there are four...... classes of IRES element which vary in size (450-270nt), they also have different, complex, secondary structures and distinct requirements for cellular proteins to allow them to function. This review describes the features of each class of picornavirus IRES element but focuses on the characteristics...... of the most recently described group, initially identified within the porcine teschovirus-1 RNA, which has strong similarities to the IRES elements from within the genomes of hepatitis C virus and the pestiviruses which are members of the flavivirus family. The selection of the initiation codon...

  12. Novel porcine repetitive elements

    Directory of Open Access Journals (Sweden)

    Nonneman Dan J

    2006-12-01

    Full Text Available Abstract Background Repetitive elements comprise ~45% of mammalian genomes and are increasingly known to impact genomic function by contributing to the genomic architecture, by direct regulation of gene expression and by affecting genomic size, diversity and evolution. The ubiquity and increasingly understood importance of repetitive elements contribute to the need to identify and annotate them. We set out to identify previously uncharacterized repetitive DNA in the porcine genome. Once found, we characterized the prevalence of these repeats in other mammals. Results We discovered 27 repetitive elements in 220 BACs covering 1% of the porcine genome (Comparative Vertebrate Sequencing Initiative; CVSI. These repeats varied in length from 55 to 1059 nucleotides. To estimate copy numbers, we went to an independent source of data, the BAC-end sequences (Wellcome Trust Sanger Institute, covering approximately 15% of the porcine genome. Copy numbers in BAC-ends were less than one hundred for 6 repeat elements, between 100 and 1000 for 16 and between 1,000 and 10,000 for 5. Several of the repeat elements were found in the bovine genome and we have identified two with orthologous sites, indicating that these elements were present in their common ancestor. None of the repeat elements were found in primate, rodent or dog genomes. We were unable to identify any of the replication machinery common to active transposable elements in these newly identified repeats. Conclusion The presence of both orthologous and non-orthologous sites indicates that some sites existed prior to speciation and some were generated later. The identification of low to moderate copy number repetitive DNA that is specific to artiodactyls will be critical in the assembly of livestock genomes and studies of comparative genomics.

  13. Fuel element store

    International Nuclear Information System (INIS)

    Wieser, R.

    1987-01-01

    The spherical fuel elements are stored dry in cans. The cans themselves are stacked in parallel storage shafts, which are combined into a rectangular storage space. The storage space is made earthquake-proof by surrounding it with concrete. It consists of a ceiling assembled from several steel parts, which is connected to the floor by support elements. A cooling air ventilation station supplies the individual storage shaft and therefore the cans with cooling air via incoming and outgoing pipes. (DG) [de

  14. Intrusion detection system elements

    International Nuclear Information System (INIS)

    Eaton, M.J.; Mangan, D.L.

    1980-09-01

    This report highlights elements required for an intrusion detection system and discusses problems which can be encountered in attempting to make the elements effective. Topics discussed include: sensors, both for exterior detection and interior detection; alarm assessment systems, with the discussion focused on video assessment; and alarm reporting systems, including alarm communication systems and dislay/console considerations. Guidance on careful planning and design of a new or to-be-improved system is presented

  15. Structural elements design manual

    CERN Document Server

    Draycott, Trevor

    2012-01-01

    Gives clear explanations of the logical design sequence for structural elements. The Structural Engineer says: `The book explains, in simple terms, and with many examples, Code of Practice methods for sizing structural sections in timber, concrete,masonry and steel. It is the combination into one book of section sizing methods in each of these materials that makes this text so useful....Students will find this an essential support text to the Codes of Practice in their study of element sizing'.

  16. Atoms, molecules & elements

    CERN Document Server

    Graybill, George

    2007-01-01

    Young scientists will be thrilled to explore the invisible world of atoms, molecules and elements. Our resource provides ready-to-use information and activities for remedial students using simplified language and vocabulary. Students will label each part of the atom, learn what compounds are, and explore the patterns in the periodic table of elements to find calcium (Ca), chlorine (Cl), and helium (He) through hands-on activities.

  17. Nuclear fuel element

    International Nuclear Information System (INIS)

    Penrose, R.T.; Thompson, J.R.

    1976-01-01

    A method of protecting the cladding of a nuclear fuel element from internal attack and a nuclear fuel element for use in the core of a nuclear reactor are disclosed. The nuclear fuel element has disposed therein an additive of a barium-containing material and the barium-containing material collects reactive gases through chemical reaction or adsorption at temperatures ranging from room temperature up to fuel element plenum temperatures. The additive is located in the plenum of the fuel element and preferably in the form of particles in a hollow container having a multiplicity of gas permeable openings in one portion of the container with the openings being of a size smaller than the size of the particles. The openings permit gases and liquids entering the plenum to contact the particles. The additive is comprised of elemental barium or a barium alloy containing one or more metals in addition to barium such as aluminum, zirconium, nickel, titanium and combinations thereof. 6 claims, 3 drawing figures

  18. Elements of Autonomous Self-Reconfigurable Robots

    DEFF Research Database (Denmark)

    Christensen, David Johan

    In this thesis, we study several central elements of autonomous self-reconfigurable modular robots. Unlike conventional robots such robots are: i) Modular, since robots are assembled from numerous robotic modules. ii) Reconfigurable, since the modules can be combined in a variety of ways. iii) Self......-reconfigurable, since the modules themselves are able to change how they are combined. iv) Autonomous, since robots control themselves without human guidance. Such robots are attractive to study since they in theory have several desirable characteristics, such as versatility, reliability and cheapness. In practice...... however, it is challenging to realize such characteristics since state-of-the-art systems and solutions suffer from several inherent technical and theoretical problems and limitations. In this thesis, we address these challenges by exploring four central elements of autonomous self-reconfigurable modular...

  19. CHALLENGES OF SOFTWARE QUALITY ASSURANCE AND TESTING

    Directory of Open Access Journals (Sweden)

    Md.Shahadat Hossain

    2018-02-01

    Full Text Available Uncertainty exists in Software Company over the world. Software quality problem is leading issue for the software industry. The issue exists from 40 years or 50 years long. The industry is suffering and closing for this issue. In this circumstance, it is important to address and remove its root cause. Otherwise, day by day industry economic loss will increase. I figure out some vital challenges of software quality assurance and testing which have been facing by software industries. The research focused on several small and medium software companies of the world. This paper represents different category of challenges along with responsible stakeholders. This research finds out that testing tools are available testing elements are available testing process has improved but still software has some testing challenges. My research figured out the bottleneck of challenges and explained in this paper. Here software engineers have scope to improve & overcome those challenges. This paper suggests systematic approach to solve the problem.

  20. Designing the robot inclusive space challenge

    Directory of Open Access Journals (Sweden)

    Rajesh Elara Mohan

    2015-11-01

    Full Text Available A novel robotic challenge, namely the robot inclusive spaces (RIS challenge, is proposed in this paper, which is a cross disciplinary and design focused initiative. It aims to foster the roboticists, architects, and designers towards realizing robot friendly social spaces. Contrary to conventional robotics competitions focusing on designing robots and its component technologies, robot inclusive spaces challenge adopts an interdisciplinary “design for robots” strategy to overcome the traditional research problem in real world deployments of social robots. In order to realize the RIS, various architectural elements must be adapted including: design principles for inclusive spaces, lighting schemes, furniture choices and arrangement, wall and floor surfaces, pathways among others. This paper introduces the format and design principles of RIS challenge, presents a first run of the challenge, and gives the corresponding analysis.

  1. Studying Nuclear Structure at the extremes with S3

    Science.gov (United States)

    Piot, Julien

    2018-05-01

    The in-depth study of the regions of Superheavy elements and the proton drip line around 100Sn are two major challenges of today's Nuclear Physics. Performing detailed spectroscopic studies on these nuclei requires a significant improvement of our detection capabilities. The Super-Separator-Spectrometer S3 is part of the SPIRAL2 facility at GANIL. Its aim is to use the high stable beam currents provided by the new LINAC to reach rare isotopes by fusion-evaporation.

  2. Peridynamic Multiscale Finite Element Methods

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Timothy [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bond, Stephen D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Littlewood, David John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Moore, Stan Gerald [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    The problem of computing quantum-accurate design-scale solutions to mechanics problems is rich with applications and serves as the background to modern multiscale science research. The prob- lem can be broken into component problems comprised of communicating across adjacent scales, which when strung together create a pipeline for information to travel from quantum scales to design scales. Traditionally, this involves connections between a) quantum electronic structure calculations and molecular dynamics and between b) molecular dynamics and local partial differ- ential equation models at the design scale. The second step, b), is particularly challenging since the appropriate scales of molecular dynamic and local partial differential equation models do not overlap. The peridynamic model for continuum mechanics provides an advantage in this endeavor, as the basic equations of peridynamics are valid at a wide range of scales limiting from the classical partial differential equation models valid at the design scale to the scale of molecular dynamics. In this work we focus on the development of multiscale finite element methods for the peridynamic model, in an effort to create a mathematically consistent channel for microscale information to travel from the upper limits of the molecular dynamics scale to the design scale. In particular, we first develop a Nonlocal Multiscale Finite Element Method which solves the peridynamic model at multiple scales to include microscale information at the coarse-scale. We then consider a method that solves a fine-scale peridynamic model to build element-support basis functions for a coarse- scale local partial differential equation model, called the Mixed Locality Multiscale Finite Element Method. Given decades of research and development into finite element codes for the local partial differential equation models of continuum mechanics there is a strong desire to couple local and nonlocal models to leverage the speed and state of the

  3. Capture and dissipation in the superheavy region

    Energy Technology Data Exchange (ETDEWEB)

    Materna, T. E-mail: tmaterna@ulb.ac.be; Aritomo, Y.; Amar, N.; Bogatchev, A.; Bouchat, V.; Dorvaux, O.; Giardina, G.; Grevy, S.; Hanappe, F.; Itkis, I.; Jandel, M.; Knyajeva, G.; Kliman, J.; Kozulin, E.; Kondratiev, N.; Krupa, L.; Peter, J.; Prokhorova, E.; Pokrovsky, I.; Schmitt, C.; Stuttge, L.; Voskresensky, V

    2004-04-05

    The competition between fusion-fission and quasi-fission in the reactions {sup 48}Ca+{sup 208}Pb and {sup 48}Ca+{sup 244}Pu(E* = 40MeV) is investigated using the pre-scission neutron multiciplicity distributions (PSNMD) obtained with a new analysis protocol.

  4. Challenges in Continuum Modelling of Intergranular Fracture

    DEFF Research Database (Denmark)

    Coffman, Valerie; Sethna, James P.; Ingraffea, A. R.

    2011-01-01

    of grain boundaries, but also in crucial ways on edges, corners and triple junctions of even greater geometrical complexity. To address the first two challenges, we explore the physical underpinnings for creating functional forms to capture the hierarchical commensurability structure in the grain boundary......Intergranular fracture in polycrystals is often simulated by finite elements coupled to a cohesive zone model for the interfaces, requiring cohesive laws for grain boundaries as a function of their geometry. We discuss three challenges in understanding intergranular fracture in polycrystals. First...... properties. To address the last challenge, we demonstrate a method for atomistically extracting the fracture properties of geometrically complex local regions on the fly from within a finite element simulation....

  5. Fuel element transport container

    International Nuclear Information System (INIS)

    Benna, P.; Neuenfeldt, W.

    1979-01-01

    The reprocessing system includes a large number of waterfilled ponds next to each other for the intermediate storage of fuel elements from LWR's. The fuel element transport device is allocated to a middle pond. The individual ponds are separated from each other by walls, and are only accessible from the middle pond via narrow passages. The transport device includes a telescopic running rail for a trolley with a grab device for the fuel element. The running rail is supported in turn by a second trolley, which can be moved by wheels on rails. Part of the drive of the first trolley is arranged on the second one. Using this transport device, adjacent ponds can be served through the passage openings. (DG) [de

  6. Nuclear fuel element

    International Nuclear Information System (INIS)

    Hirayama, Satoshi; Kawada, Toshiyuki; Matsuzaki, Masayoshi.

    1980-01-01

    Purpose: To provide a fuel element for reducing the mechanical interactions between a fuel-cladding tube and the fuel element and for alleviating the limits of the operating conditions of a reactor. Constitution: A fuel element having mainly uranium dioxide consists of a cylindrical outer pellet and cylindrical inner pellet inserted into the outer pellet. The outer pellet contains two or more additives selected from aluminium oxide, beryllium oxide, magnesium oxide, silicon oxide, sodium oxide, phosphorus oxide, calcium oxide and iron oxide, and the inner pellet contains nuclear fuel substance solely or one additive selected from calcium oxide, silicon oxide, aluminium oxide, magnesium oxide, zirconium oxide and iron oxide. The outer pellet of the fuel thus constituted is reduced in mechanical strength and also in the mechanical interactions with the cladding tube, and the plastic fluidity of the entire pellet is prevented by the inner pellet increased in the mechanical strength. (Kamimura, M.)

  7. Creativity Management Key Elements

    Directory of Open Access Journals (Sweden)

    Rosa María Fuchs Ángeles

    2015-09-01

    Full Text Available Organizations are constantly looking towards innovation. In order to reach it they must foment creativity. This paper analyzes a series of elements considered in the organizational creativity management and proposes a model with the indispensable factors that organizations should consider to reach it. These elements are: culture and organizational environment, strategy, structure, communication, relation with customers, human resources (recruiting, training, job design, compensation, promotion, and performance evaluation, long term orientation and the organizational life cycle. Having the analysis of those elements as a basis, the indispensable pillars on management creativity are identified. The proposed model is based on 5 pillars: the alignment between strategic, culture and organizational structure, called by the authors 'Holy Trinity'; intern publicity; customer’s voice; recognition and a look towards future. Finally, the case of an innovative Peruvian enterprise is presented from the model’s perspective and the study conclusions.

  8. Fuel Element Technical Manual

    Energy Technology Data Exchange (ETDEWEB)

    Burley, H.H. [ed.

    1956-08-01

    It is the purpose of the Fuel Element Technical Manual to Provide a single document describing the fabrication processes used in the manufacture of the fuel element as well as the technical bases for these processes. The manual will be instrumental in the indoctrination of personnel new to the field and will provide a single data reference for all personnel involved in the design or manufacture of the fuel element. The material contained in this manual was assembled by members of the Engineering Department and the Manufacturing Department at the Hanford Atomic Products Operation between the dates October, 1955 and June, 1956. Arrangement of the manual. The manual is divided into six parts: Part I--introduction; Part II--technical bases; Part III--process; Part IV--plant and equipment; Part V--process control and improvement; and VI--safety.

  9. Elements of social security

    DEFF Research Database (Denmark)

    Hansen, Hans

    Elements of Social Security is a comparative study of important elements of the social security systems in Denmark (DK), Sweden (S), Finland (FIN), Austria (A), Germany (D), the Netherlands (NL), Great Britain (GB) and Canada (CAN). It should be emphasized that Germany is the former West Germany...... (Alte Länder). This is the 9th and last edition of the publication,covering income levels and rules for social security and personal taxation for 1999. Basis for the projections to 1999 income levels is the 1998 data (in some cases 1999 data)for OECD's Taxing Wages as reported by national experts....

  10. Elements of linear space

    CERN Document Server

    Amir-Moez, A R; Sneddon, I N

    1962-01-01

    Elements of Linear Space is a detailed treatment of the elements of linear spaces, including real spaces with no more than three dimensions and complex n-dimensional spaces. The geometry of conic sections and quadric surfaces is considered, along with algebraic structures, especially vector spaces and transformations. Problems drawn from various branches of geometry are given.Comprised of 12 chapters, this volume begins with an introduction to real Euclidean space, followed by a discussion on linear transformations and matrices. The addition and multiplication of transformations and matrices a

  11. Bibliography on transuranium elements

    International Nuclear Information System (INIS)

    Sood, D.D.

    1991-01-01

    A selective bibliography of prominent publications on transuranium elements is compiled. Heading papers, symposia proceedings and the textbooks are included in the bibliography. The bibliography is arranged under the headings: (1)Books, Symposia Proceedings, Reviews etc., (2)Discovery, (3)Weighable Isolation, (4)Metal Preparation, (5)Nuclear Properties, (6)Plutonium as Reactor Fuel, (7)Fuel Reprocessing, (8)Solid State Chemistry, Thermochemistry and Spectroscopy, (9)Radiation Safety, (10)Applications, and (11)Some Typical Indian Papers. Total number of references cited are 298. The bibliography, though selective, will serve as a starting point for comprehensive literature search on transuranium elements. (author)

  12. Finite elements and approximation

    CERN Document Server

    Zienkiewicz, O C

    2006-01-01

    A powerful tool for the approximate solution of differential equations, the finite element is extensively used in industry and research. This book offers students of engineering and physics a comprehensive view of the principles involved, with numerous illustrative examples and exercises.Starting with continuum boundary value problems and the need for numerical discretization, the text examines finite difference methods, weighted residual methods in the context of continuous trial functions, and piecewise defined trial functions and the finite element method. Additional topics include higher o

  13. Night Rover Challenge

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the Night Rover Challenge was to foster innovations in energy storage technology. Specifically, this challenge asked competitors to create an energy...

  14. National Drug IQ Challenge

    Science.gov (United States)

    ... National Drug IQ Challenge 2017 Reto nacional del coeficiente intelectual (CI) sobre las drogas y el alcohol 2016 National Drug IQ Challenge 2016 Reto nacional del coeficiente intelectual (CI) sobre las drogas y el alcohol 2015 ...

  15. Elemental imaging at the nanoscale: NanoSIMS and complementary techniques for element localisation in plants.

    Science.gov (United States)

    Moore, Katie L; Lombi, Enzo; Zhao, Fang-Jie; Grovenor, Chris R M

    2012-04-01

    The ability to locate and quantify elemental distributions in plants is crucial to understanding plant metabolisms, the mechanisms of uptake and transport of minerals and how plants cope with toxic elements or elemental deficiencies. High-resolution secondary ion mass spectrometry (SIMS) is emerging as an important technique for the analysis of biological material at the subcellular scale. This article reviews recent work using the CAMECA NanoSIMS to determine elemental distributions in plants. The NanoSIMS is able to map elemental distributions at high resolution, down to 50 nm, and can detect very low concentrations (milligrams per kilogram) for some elements. It is also capable of mapping almost all elements in the periodic table (from hydrogen to uranium) and can distinguish between stable isotopes, which allows the design of tracer experiments. In this review, particular focus is placed upon studying the same or similar specimens with both the NanoSIMS and a wide range of complementary techniques, showing how the advantages of each technique can be combined to provide a fuller data set to address complex scientific questions. Techniques covered include optical microscopy, synchrotron techniques, including X-ray fluorescence and X-ray absorption spectroscopy, transmission electron microscopy, electron probe microanalysis, particle-induced X-ray emission and inductively coupled plasma mass spectrometry. Some of the challenges associated with sample preparation of plant material for SIMS analysis, the artefacts and limitations of the technique and future trends are also discussed.

  16. Elements of Social Security

    DEFF Research Database (Denmark)

    Hansen, Hans

    Elements of Social Security contains an overview of important benefit schemes in Denmark, Sweden, Finland, Austria, Germany, the Netherlands, Great Britain and Canada. The schemes are categorized according to common sets of criteria and compared. Stylized cases illustrate the impact on disposable...

  17. Elements of Social Security

    DEFF Research Database (Denmark)

    Hansen, Hans

    Elements of Social Security contains an overview of important benefit schemes in Denmark, Sweden, Finland, Germany, the Netherlands, Great Britain and Canada. The schemes are categorized according to common sets of criteria and compared. Stylized cases illustrate the impact on disposable income...

  18. Elements of Social Security

    DEFF Research Database (Denmark)

    Hansen, Hans

    Elements of Social Security contains an overview of important benefit schemes in Denmark, Sweden, Finland, Germany, Great Britain, the Netherlands and Canada. The schemes are categorized according to common sets of criteria and compared. Stylized cases illustrate the impact on disposable income...

  19. Water, the intangible element

    NARCIS (Netherlands)

    Schotting, R.J.

    2009-01-01

    Water is the key to life. No living creature can survive without water. Too much water or polluted water are serious threats to mankind. Managing this intangible element is complex, not only in wet deltaic regions but also in the (semi-)arid regions of the world. Combined efforts of the

  20. Movies and Literary Elements.

    Science.gov (United States)

    Keller, Rodney D.

    1987-01-01

    Recommends using movie clips to stimulate students' interest in reading a novel as well as to teach elements of fiction such as plot, character, setting, symbol, irony, and theme. Describes each clip and provides study questions. Includes a listing of movies made from books. (NH)

  1. Elements of Architecture

    DEFF Research Database (Denmark)

    Elements of Architecture explores new ways of engaging architecture in archaeology. It conceives of architecture both as the physical evidence of past societies and as existing beyond the physical environment, considering how people in the past have not just dwelled in buildings but have existed...

  2. Inside finite elements

    CERN Document Server

    Weiser, Martin

    2016-01-01

    All relevant implementation aspects of finite element methods are discussed in this book. The focus is on algorithms and data structures as well as on their concrete implementation. Theory is covered as far as it gives insight into the construction of algorithms. Throughout the exercises a complete FE-solver for scalar 2D problems will be implemented in Matlab/Octave.

  3. Plants' essential chemical elements

    Science.gov (United States)

    Kevin T. Smith

    2007-01-01

    Every garden center and hardware store sells fertilizer guaranteed to "feed" plants. In a strict sense, we can't feed plants. Food contains an energy source. Green plants capture solar energy and make their own food through photosynthesis! Photosynthesis and other metabolic processes require chemical elements in appropriate doses for plants to survive...

  4. Elements of relativity theory

    International Nuclear Information System (INIS)

    Lawden, D.F.

    1985-01-01

    The book on elements of relativity theory is intended for final year school students or as an early university course in mathematical physics. Special principle of relativity, lorentz transformation, velocity transformations, relativistic mechanics, and general theory of relativity, are all discussed. (U.K.)

  5. Photovoltaic radiation detector element

    International Nuclear Information System (INIS)

    Agouridis, D.C.

    1980-01-01

    A radiation detector element is formed of a body of semiconductor material, a coating on the body which forms a photovoltaic junction therewith, and a current collector consisting of narrow metallic strips, the aforesaid coating having an opening therein in the edge of which closely approaches but is spaced from the current collector strips

  6. CHALLENGES IN CROSS CULTURAL ADVERTISING

    Directory of Open Access Journals (Sweden)

    Yuni Retnowati

    2016-04-01

    Full Text Available At first, marketing practitioners and academics consider standardized approaches to marketing and advertising strategies in globalization, and then some studies proved that the standardization of advertising across culture is not valid. Therefore, cross cultural advertising takes local culture into account when conveying messages in advertisements. Cross cultural understanding is very important in order to produce successful localized advertising that would reflect the cultural values and norms of intended audience. Challenge in cross cultural advertising is the problem of communicating to people of diverse cultural background. Cross cultural solutions are applied in areas such as language, communication style, images and cultural values. Cross cultural advertising is simply about using common sense and analyzing how the different elements of an advertising campaign are impacted by culture and modifying them to best speak to the target audience. Other challenges are determining between standardization and adaptation of cultural values content of advertising when facing different people from diverse cultures. In academic side, the challenge is preparing students to design advertisements that communicate effectively to diverse cultures.

  7. 'Blue Whale Challenge': A Game or Crime?

    Science.gov (United States)

    Mukhra, Richa; Baryah, Neha; Krishan, Kewal; Kanchan, Tanuj

    2017-11-11

    A bewildering range of games are emerging every other day with newer elements of fun and entertainment to woo youngsters. Games are meant to reduce stress and enhance the cognitive development of children as well as adults. Teenagers are always curious to indulge in newer games; and e-gaming is one such platform providing an easy access and quicker means of entertainment. The particular game challenge which has taken the world by storm is the dangerous "Blue Whale Challenge" often involving vulnerable teenagers. The Blue Whale Challenge is neither an application nor internet based game but the users get a link through social media chat groups to enter this "deadly" challenge game. This probably is the only game where the participant has to end his/her life to complete the game. The innocent teenagers are being targeted based on their depressed psychology and are coercively isolated from their social milieux on the pretext of keeping the challenges confidential. To add to the woes, no option is offered to quit the challenge even if the contender is unable to complete the challenge. Blue Whale Challenge in its sheer form could be seen as an illegal, unethical and inhumane endeavor in our present society. The present communication discusses the severe effects of the game on teenagers, the ethical concerns involved and the preventive measures necessary to curb it.

  8. Element-topology-independent preconditioners for parallel finite element computations

    Science.gov (United States)

    Park, K. C.; Alexander, Scott

    1992-01-01

    A family of preconditioners for the solution of finite element equations are presented, which are element-topology independent and thus can be applicable to element order-free parallel computations. A key feature of the present preconditioners is the repeated use of element connectivity matrices and their left and right inverses. The properties and performance of the present preconditioners are demonstrated via beam and two-dimensional finite element matrices for implicit time integration computations.

  9. Neutron-rich isotopes of the lightest elements

    International Nuclear Information System (INIS)

    Oganesyan, Yu.Ts.; Penionzhkevich, Yu.Eh.; Kalpakchieva, R.

    1989-01-01

    A review is presented of the experimental investigations on the stability of very neutron-rich light nuclei carried out at the JINR Laboratory of Nuclear Reactions. Results on mass excess measurements are reported for 4 H, 5 H, 6 H, 7 H and for the superheavy helium isotope 9 He. Some results from the joint JINR-Ganil experiment on the search for and study of new neutron-rich light nuclei are also given. Analyzed are new possibilities for the investigation of multineutron decay of light nuclei. 14 refs.; 10 figs

  10. Application of Mass Lumped Higher Order Finite Elements

    International Nuclear Information System (INIS)

    J. Chen, H.R. Strauss, S.C. Jardin, W. Park, L.E. Sugiyama, G. Fu, J. Breslau

    2005-01-01

    There are many interesting phenomena in extended-MHD such as anisotropic transport, mhd, 2-fluid effects stellarator and hot particles. Any one of them challenges numerical analysts, and researchers are seeking for higher order methods, such as higher order finite difference, higher order finite elements and hp/spectral elements. It is true that these methods give more accurate solution than their linear counterparts. However, numerically they are prohibitively expensive. Here we give a successful solution of this conflict by applying mass lumped higher order finite elements. This type of elements not only keep second/third order accuracy but also scale closely to linear elements by doing mass lumping. This is especially true for second order lump elements. Full M3D and anisotropic transport models are studied

  11. Archaeal extrachromosomal genetic elements

    DEFF Research Database (Denmark)

    Wang, Haina; Peng, Nan; Shah, Shiraz Ali

    2015-01-01

    SUMMARY: Research on archaeal extrachromosomal genetic elements (ECEs) has progressed rapidly in the past decade. To date, over 60 archaeal viruses and 60 plasmids have been isolated. These archaeal viruses exhibit an exceptional diversity in morphology, with a wide array of shapes, such as spind......SUMMARY: Research on archaeal extrachromosomal genetic elements (ECEs) has progressed rapidly in the past decade. To date, over 60 archaeal viruses and 60 plasmids have been isolated. These archaeal viruses exhibit an exceptional diversity in morphology, with a wide array of shapes...... on archaeal ECEs has just started to unravel the molecular biology of these genetic entities and their interactions with archaeal hosts, it is expected to accelerate in the next decade....

  12. Nuclear fuel element

    Energy Technology Data Exchange (ETDEWEB)

    Armijo, J S; Coffing, L F

    1979-04-05

    The fuel element with circular cross-section for BWR and PWR consists of a core surrounded by a compound jacket container where there is a gap between the core and jacket during operation in the reactor. The core consists of U, Pu, Th compounds and mixtures of these. The compound jacket consists of zircaloy 2 or 4. In order to for example prevent the corrosion of the compound jacket, its inner surface has a metal barrier with smaller neutron absorbers than the jacket material in the form of a zirconium sponge. The zirconium of this metal barrier has impurities of various elements in the order of magnitude of 1000 to 5000 ppm. The oxygen content is in the range of 200 to 1200 ppm and the thickness of the metal barrier is 1-30% of the thickness of the jacket.

  13. Nuclear reactor fuel element

    International Nuclear Information System (INIS)

    D'Eye, R.W.M.; Shennan, J.V.; Ford, L.H.

    1977-01-01

    Fuel element with particles from ceramic fissionable material (e.g. uranium carbide), each one being coated with pyrolitically deposited carbon and all of them being connected at their points of contact by means of an individual crossbar. The crossbar consists of silicon carbide produced by reaction of silicon metal powder with the carbon under the influence of heat. Previously the silicon metal powder together with the particles was kneaded in a solvent and a binder (e.g. epoxy resin in methyl ethyl ketone plus setting agent) to from a pulp. The reaction temperature lies at 1750 0 C. The reaction itself may take place in a nitrogen atmosphere. There will be produced a fuel element with a high overall thermal conductivity. (DG) [de

  14. Nuclear fuel element

    International Nuclear Information System (INIS)

    1974-01-01

    A nuclear fuel element for use in the core of a nuclear reactor is disclosed. A heat conducting fission product retaining metal liner of a refractory metal is incorporated in the fuel element between the cladding and the nuclear fuel to inhibit mechanical interaction between the nuclear fuel and the cladding, to isolate fission products and nuclear fuel impurities from contacting the cladding, and to improve the axial thermal peaking gradient along the length of the fuel rod. The metal liner can be in the form of a tube or hollow cylindrical column, a foil of single or multiple layers in the shape of a hollow cylindrical column, or a coating on the internal surface of the cladding. Preferred refractory metal materials are molybdenum, tungsten, rhenium, niobium and alloys of the foregoing metals

  15. Nuclear fuel element

    International Nuclear Information System (INIS)

    Thompson, J.R.; Rowland, T.C.

    1976-01-01

    A nuclear fuel element for use in the core of a nuclear reactor is disclosed. A heat conducting, fission product retaining metal liner of a refractory metal is incorporated in the fuel element between the cladding and the nuclear fuel to inhibit mechanical interaction between the nuclear fuel and the cladding, to isolate fission products and nuclear fuel impurities from contacting the cladding and to improve the axial thermal peaking gradient along the length of the fuel rod. The metal liner can be in the form of a tube or hollow cylindrical column, a foil of single or multiple layers in the shape of a hollow cylindrical column, or a coating on the internal surface of the cladding. Preferred refractory metal materials are molybdenum, tungsten, rhenium, niobium and alloys of the foregoing metals

  16. Elements of quantum optics

    CERN Document Server

    Meystre, Pierre

    2007-01-01

    Elements of Quantum Optics gives a self-contained and broad coverage of the basic elements necessary to understand and carry out research in laser physics and quantum optics, including a review of basic quantum mechanics and pedagogical introductions to system-reservoir interactions and to second quantization. The text reveals the close connection between many seemingly unrelated topics, such as probe absorption, four-wave mixing, optical instabilities, resonance fluorescence and squeezing. It also comprises discussions of cavity quantum electrodynamics and atom optics. The 4th edition includes a new chapter on quantum entanglement and quantum information, as well as added discussions of the quantum beam splitter, electromagnetically induced transparency, slow light, and the input-output formalism needed to understand many problems in quantum optics. It also provides an expanded treatment of the minimum-coupling Hamiltonian and a simple derivation of the Gross-Pitaevskii equation, an important gateway to rese...

  17. Periodic table of elements

    International Nuclear Information System (INIS)

    Fluck, E.; Heumann, K.G.

    1985-01-01

    Following a recommendation by the International Union for Pure and Applied Chemistry (IUPAC), the groups of the periodic table shall be numbered from 1 to 18, instead of I to VIII as before. The recommendations has been approved of by the Committee on Nomenclature of the American Chemical Society. The new system abandons the distinction between main groups (a) and auxiliary groups (b), which in the past frequently has been the reason for misunderstandings between European and American chemists, due to different handling. The publishing house VCH Verlagsgesellschaft recently produced a new periodic table that shows the old and the new numbering system together at a glance, so that chemists will have time to get familiar with the new system. In addition the new periodic table represents an extensive data compilation arranged by elements. The front page lists the chemical properties of elements, the back page their physical properties. (orig./EF) [de

  18. Nuclear fuel elements

    International Nuclear Information System (INIS)

    Kawada, Toshiyuki; Hirayama, Satoshi; Yoneya, Katsutoshi.

    1980-01-01

    Purpose: To enable load-depending operation as well as moderation for the restriction of operation conditions in the present nuclear reactors, by specifying the essential ingredients and the total weight of the additives to UO 2 fuel substances. Constitution: Two or more additives selected from Al 2 O 3 , B 2 O, CaO, MgO, SiO 2 , Na 2 O and P 2 O 5 are added by the total weight of 2 - 5% to fuel substances consisting of UO 2 or a mixture of UO 2 and PuO 2 . When the mixture is sintered, the strength of the fuel elements is decreased and the fuel-cladding interactions due to the difference in the heat expansion coefficients between the ceramic fuel elements and the metal claddings are decreased to a substantially harmless degree. (Horiuchi, T.)

  19. Nuclear fuel elements

    International Nuclear Information System (INIS)

    Nakai, Keiichi

    1983-01-01

    Purpose: To decrease the tensile stresses resulted in a fuel can as well as prevent decladding of fuel pellets into the bore holes by decreasing the inner pressure within the nuclear fuel element. Constitution: A fuel can is filled with hollow fuel pellets, inserted with a spring for retaining the hollow fuel pellets with an appropriate force and, thereafter, closely sealed at the both ends with end plugs. A cylindrical body is disposed into the bore holes of the hollow fuel pellets. Since initial sealing gases and/or gaseous nuclear fission products can thus be excluded from the bore holes where the temperature is at the highest level, the inner pressure of the nuclear fuel element can be reduced to decrease the tensile strength resulted to the fuel can. Furthermore, decladding of fuel pellets into the bore holes can be prevented. (Moriyama, K.)

  20. Nuclear fuel elements

    International Nuclear Information System (INIS)

    Ainsworth, K.F.

    1979-01-01

    A nuclear fuel element is described having a cluster of nuclear fuel pins supported in parallel, spaced apart relationship by transverse cellular braces within coaxial, inner and outer sleeves, the inner sleeve being in at least two separate axial lengths, each of the transverse braces having a peripheral portion which is clamped peripherally between the ends of the axial lengths of the inner sleeve. (author)

  1. Sensor for ionizable elements

    International Nuclear Information System (INIS)

    Berkey, E.; Reed, W.A. III; Hickam, W.M.

    1977-01-01

    Sensor to detect thermally ionizable elements or molucules in air, water vapour or oxygen or to be used as alkali leak detector in vacuum systems, e.g. in the pipe system of a liquid-metal cooled FBR. The sensor consists of an filament made of thorium-containing iridium as cathode with a temperature upto 1000 0 C and an anode sheet of molybdenum, nickel or stainless steal. (ORU) [de

  2. Nuclear reactor fuel elements

    International Nuclear Information System (INIS)

    Butterfield, C.E.; Waite, E.

    1982-01-01

    A nuclear reactor fuel element comprising a column of vibration compacted fuel which is retained in consolidated condition by a thimble shaped plug. The plug is wedged into gripping engagement with the wall of the sheath by a wedge. The wedge material has a lower coefficient of expansion than the sheath material so that at reactor operating temperature the retainer can relax sufficient to accommodate thermal expansion of the column of fuel. (author)

  3. OXIDATION OF TRANSURANIC ELEMENTS

    Science.gov (United States)

    Moore, R.L.

    1959-02-17

    A method is reported for oxidizing neptunium or plutonium in the presence of cerous values without also oxidizing the cerous values. The method consists in treating an aqueous 1N nitric acid solution, containing such cerous values together with the trivalent transuranic elements, with a quantity of hydrogen peroxide stoichiometrically sufficient to oxidize the transuranic values to the hexavalent state, and digesting the solution at room temperature.

  4. Transportation of radioactive elements

    International Nuclear Information System (INIS)

    Thubert, Francis; Rentien, Guy; Jacquet, Michel

    1981-01-01

    The production and marketing of artificial radioactive elements engaged in by the 'Office des Rayonnements Ionisants' requires the use of specially designed packagings and assorted means of transport. The authors begin by describing the different kinds of products involved and the forms of packagings needed, and go on to discuss the various means of transport used, underlining the fact that, in terms of number and gravity, the incidents that have occurred to date have indeed been few and far between [fr

  5. Vented nuclear fuel element

    International Nuclear Information System (INIS)

    Oguma, M.; Hirose, Y.

    1976-01-01

    A description is given of a vented nuclear fuel element having a plenum for accumulation of fission product gases and plug means for delaying the release of the fission product gases from the plenum, the plug means comprising a first porous body wettable with a liquid metal and a second porous body non-wettable with the liquid metal, the first porous body being impregnated with the liquid metal and in contact with the liquid metal

  6. Helium the disappearing element

    CERN Document Server

    Sears, Wheeler M

    2015-01-01

    The subject of the book is helium, the element, and its use in myriad applications including MRI machines, particle accelerators, space telescopes, and of course balloons and blimps. It was at the birth of our Universe, or the Big Bang, where the majority of cosmic helium was created; and stellar helium production continues. Although helium is the second most abundant element in the Universe, it is actually quite rare here on Earth and only exists because of radioactive elements deep within the Earth. This book includes a detailed history of the discovery of helium, of the commercial industry built around it, how the helium we actually encounter is produced within the Earth, and the state of the helium industry today. The gas that most people associate with birthday party balloons is running out. “Who cares?” you might ask. Well, without helium, MRI machines could not function, rockets could not go into space, particle accelerators such as those used by CERN could not operate, fiber optic cables would not...

  7. Elements of quantum information

    International Nuclear Information System (INIS)

    Schleich, W.P.

    2007-01-01

    Elements of Quantum Information introduces the reader to the fascinating field of quantum information processing, which lives on the interface between computer science, physics, mathematics, and engineering. This interdisciplinary branch of science thrives on the use of quantum mechanics as a resource for high potential modern applications. With its wide coverage of experiments, applications, and specialized topics - all written by renowned experts - Elements of Quantum Information provides and indispensable, up-to-date account of the state of the art of this rapidly advancing field and takes the reader straight up to the frontiers of current research. The articles have first appeared as a special issue of the journal 'Fortschritte der Physik / Progress of Physics'. Since then, they have been carefully updated. The book will be an inspiring source of information and insight for anyone researching and specializing in experiments and theory of quantum information. Topics addressed in Elements of Quantum Information include - Cavity Quantum Electrodynamics - Segmented Paul Traps - Cold Atoms and Bose-Einstein Condensates in Microtraps, Optical Lattices, and on Atom Chips - Rydberg Gases - Factorization of Numbers with Physical Systems - Entanglement of Continuous Variables - NMR and Solid State Quantum Computation - Quantum Algorithms and Quantum Machines - Complexity Theory - Quantum Crytography. (orig.)

  8. Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    M.H.R. Ghoreishy

    2008-02-01

    Full Text Available This research work is devoted to the footprint analysis of a steel-belted radial tyre (185/65R14 under vertical static load using finite element method. Two models have been developed in which in the first model the tread patterns were replaced by simple ribs while the second model was consisted of details of the tread blocks. Linear elastic and hyper elastic (Arruda-Boyce material models were selected to describe the mechanical behavior of the reinforcing and rubbery parts, respectively. The above two finite element models of the tyre were analyzed under inflation pressure and vertical static loads. The second model (with detailed tread patterns was analyzed with and without friction effect between tread and contact surfaces. In every stage of the analysis, the results were compared with the experimental data to confirm the accuracy and applicability of the model. Results showed that neglecting the tread pattern design not only reduces the computational cost and effort but also the differences between computed deformations do not show significant changes. However, more complicated variables such as shape and area of the footprint zone and contact pressure are affected considerably by the finite element model selected for the tread blocks. In addition, inclusion of friction even in static state changes these variables significantly.

  9. Probabilistic finite elements

    Science.gov (United States)

    Belytschko, Ted; Wing, Kam Liu

    1987-01-01

    In the Probabilistic Finite Element Method (PFEM), finite element methods have been efficiently combined with second-order perturbation techniques to provide an effective method for informing the designer of the range of response which is likely in a given problem. The designer must provide as input the statistical character of the input variables, such as yield strength, load magnitude, and Young's modulus, by specifying their mean values and their variances. The output then consists of the mean response and the variance in the response. Thus the designer is given a much broader picture of the predicted performance than with simply a single response curve. These methods are applicable to a wide class of problems, provided that the scale of randomness is not too large and the probabilistic density functions possess decaying tails. By incorporating the computational techniques we have developed in the past 3 years for efficiency, the probabilistic finite element methods are capable of handling large systems with many sources of uncertainties. Sample results for an elastic-plastic ten-bar structure and an elastic-plastic plane continuum with a circular hole subject to cyclic loadings with the yield stress on the random field are given.

  10. Key ecological challenges for closed systems facilities

    Science.gov (United States)

    Nelson, Mark; Dempster, William F.; Allen, John P.

    2013-07-01

    Closed ecological systems are desirable for a number of purposes. In space life support systems, material closure allows precious life-supporting resources to be kept inside and recycled. Closure in small biospheric systems facilitates detailed measurement of global ecological processes and biogeochemical cycles. Closed testbeds facilitate research topics which require isolation from the outside (e.g. genetically modified organisms; radioisotopes) so their ecological interactions and fluxes can be studied separate from interactions with the outside environment. But to achieve and maintain closure entails solving complex ecological challenges. These challenges include being able to handle faster cycling rates and accentuated daily and seasonal fluxes of critical life elements such as carbon dioxide, oxygen, water, macro- and mico-nutrients. The problems of achieving sustainability in closed systems for life support include how to handle atmospheric dynamics including trace gases, producing a complete human diet, recycling nutrients and maintaining soil fertility, the maintenance of healthy air and water and preventing the loss of critical elements from active circulation. In biospheric facilities, the challenge is also to produce analogues to natural biomes and ecosystems, studying processes of self-organization and adaptation in systems that allow specification or determination of state variables and cycles which may be followed through all interactions from atmosphere to soils. Other challenges include the dynamics and genetics of small populations, the psychological challenges for small isolated human groups and backup technologies and strategic options which may be necessary to ensure long-term operation of closed ecological systems.

  11. Recycling of Rare Earth Elements

    Science.gov (United States)

    Lorenz, Tom; Bertau, Martin

    2017-01-01

    Any development of an effective process for rare earth (RE) recycling has become more and more challenging, especially in recent years. Since 2011, when commodity prices of REs had met their all-time maximum, prices have dropped rapidly by more than 90 %. An economic process able to offset these fluctuations has to take unconventional methods into account beside well-known strategies like acid/basic leaching or solvent extraction. The solid-state chlorination provides such an unconventional method for mobilizing RE elements from waste streams. Instead of hydrochloric acid this kind of chlorination decomposes NH4Cl thermally to release up to 400 °C hot HCl gas. After cooling the resulting solid metal chlorides may be easily dissolved in pH-adjusted water. Without producing strongly acidic wastes and with NH4Cl as cheap source for hydrogen chloride, solid-state chlorination provides various advantages in terms of costs and disposal. In the course of the SepSELSA project this method was examined, adjusted and optimized for RE recycling from fluorescent lamp scraps as well as Fe14Nd2B magnets. Thereby many surprising influences and trends required various analytic methods to examine the reasons and special mechanisms behind them.

  12. Grand Challenges for Environmental Magnetism

    Science.gov (United States)

    Verosub, K. L.

    2009-05-01

    The development of new, inexpensive, and rapid geochemical methods for determining the ages of geologic materials, their elemental composition, and their isotopic ratios over a broad array of elements puts into sharp focus the question: What information can environmental magnetic methods provide that can't be obtained using these other methods? Because iron is ubiquitous in the Earth's crust and because it exists in so many different forms, a discipline that looks in detail at iron-bearing minerals does have the potential to make significant contributions to the study of surficial processes. However, to reach that potential requires the development of new environmental magnetic methods. I would like to put forward three Grand Challenges for environmental magnetism that have the potential to move the field forward to a new level of scientific sophistication and that will allow environmental magnetists to compete successfully in a world increasingly dominated by geochemists. The first Grand Challenge is the development of new techniques that lead to the direct and unambiguous identification of the full suite of magnetic minerals. For many environmental magnetic applications, the key magnetic minerals are not just magnetite and hematite but also iron oxy-hydroxides (goethite, lepidocrocite, akaganeite, ferrihydrite), carbonates (siderite) and sulfides (pyrrhotite and greigite) as well as compounds involving iron and other transition metals (cobalt and nickel). The second Grand Challenge is the development of new analytical methods that provide specific quantitative values for the amount of each magnetic mineral present in a sample. One promising approach to this problem is the application of two- or three-component multivariate analysis to arrays of downcore environmental magnetic parameters. The third Grand Challenge is the development of new ways of determining, not just the average values, but the actual distributions of grain sizes and coercivities of each mineral

  13. Control challenges in domestic heating systems

    DEFF Research Database (Denmark)

    Thybo, Honglian; Larsen, Lars F. S.; Weitzmann, Peter

    2007-01-01

    The objective of this paper is to analyze domestic heating applications and identify unfavorable building constructions and control challenges to be addressed by high performance heating control systems. Heating of domestic houses use a large amount of the total energy consumption in Scandinavia....... Hence the potential of reducing energy consumption by applying high performance control is vast. Indoor climate issues are becoming more in focus, which also leads to a demand for high performance heating systems. The paper presents an analysis of how the building elements of today's domestic houses...... with water based floor heating affect the control challenge. The analysis is documented with simulation results....

  14. The GREAT3 challenge

    International Nuclear Information System (INIS)

    Miyatake, H; Mandelbaum, R; Rowe, B

    2014-01-01

    The GRavitational lEnsing Accuracy Testing 3 (GREAT3) challenge is an image analysis competition that aims to test algorithms to measure weak gravitational lensing from astronomical images. The challenge started in October 2013 and ends 30 April 2014. The challenge focuses on testing the impact on weak lensing measurements of realistically complex galaxy morphologies, realistic point spread function, and combination of multiple different exposures. It includes simulated ground- and space-based data. The details of the challenge are described in [1], and the challenge website and its leader board can be found at http://great3challenge.info and http://great3.projects.phys.ucl.ac.uk/leaderboard/, respectively

  15. Deepwater development - the metocean challenges

    International Nuclear Information System (INIS)

    Graham, C.

    1998-01-01

    As the focus of the offshore industry moves increasingly towards deepwater, attention is concentrating more and more on life-cycle field development costs. Key elements are reducing development lead times, equipment standardisation and efficient use of scarce resources. An essential precursor is a clear definition of the metocean environment. Without it, engineering design may be unnecessarily conservative or inadequate. Either way the consequences will be expensive. It is the metocean challenge to help bring down costs, while maintaining adequate safety levels by providing the necessary answers, but most important of all, to do this in sufficient time to be in step with the engineering requirements at each stage of a planned development. (author)

  16. The new challenges of petroleum

    International Nuclear Information System (INIS)

    Gernelle, E.

    2006-02-01

    Petroleum in in the center of our civilization: abundant, easy to use and energy powerful, it is used almost everywhere: transports, lighting, space heating, plastics, fertilizers, cloth industry etc. The 'black-gold' is the object of all stakes, from richness to power. However, petroleum is also at the origin of many evils: pollution, corruption, violence. Today, petroleum is a source of worries: how long will it last? How long will we be able to stand its impacts on environment? This book shades light on all these questions and supplies some concrete elements about this energy source. Content: technological challenges of petroleum; producers: powers and risks; consumers' dependence; to learn more about petroleum. (J.S.)

  17. Methodological challenges and lessons learned

    DEFF Research Database (Denmark)

    Nielsen, Poul Erik; Gustafsson, Jessica

    2017-01-01

    Taking as point of departure three recently conducted empirical studies, the aim of this article is to theoretically and empirically discuss methodological challenges studying the interrelations between media and social reality and to critically reflect on the methodologies used in the studies....... By deconstructing the studies, the article draws attention to the fact that different methods are able to grasp different elements of social reality. Moreover, by analysing the power relations at play, the article demonstrated that the interplay between interviewer and interviewee, and how both parties fit...... into present power structures, greatly influence the narratives that are co-produced during interviews. The article thus concludes that in order to fully understand complex phenomena it is not just enough to use a mixture of methods, the makeup of the research team is also imperative, as a diverse team...

  18. Millennium Challenge Account

    National Research Council Canada - National Science Library

    Tarnoff, Curt

    2008-01-01

    .... foreign aid initiative. The Millennium Challenge Account (MCA) provides assistance through a competitive selection process to developing nations that are pursing political and economic reforms in three areas...

  19. Elements of social action

    Directory of Open Access Journals (Sweden)

    Marjanović Miloš

    2011-01-01

    Full Text Available Because of the significant analytical advantages, the author prefers social action as initial sociological concept in the relation to social phenomenon. Its basic elements are: actors, subjects and tools, needs and interests, values and norms, positions and roles. Actors set in motion and unify the rest of elements, guide to the magic triangle of sociology (movement, change, order, reaffirm actor paradigm to systemic paradigm. Subjects and tools materialize an action and its overestimate results in technological determinism or (by means of property as institutional appropriation of nature in the (unclassed historical type of society. Needs and interests are the basis of person's motivation and starting point for depth analysis of sociability. The expansion of legitimate interests circle develops techniques of normative regulation. Values and norms guide to institutional-organizational, positions to vertical and roles to horizontal structure. Values give the meaning to the action as well as to human existence, they are orientations of motivate system of personality but also basic aspect of society. As abstractions, values are latent background of norms and they tell to us what to do, and norms how to do something. Norms are specified instructions for suitable behavior Without normative order, not to be possible the satisfying of needs and the conciliation of interests. Riches, power and prestige are components of social position, and legal status is the determination of rights and obligations of the position. Roles are normative expectation of behavior. Toward kinds of sanctions roles are classified. Roles but also other elements of social action are starting point for sociological analysis of legal norms and institutes. On the other side, the observation of legal component of social actions enriches, strengths and precises sociological analysis of them.

  20. Analytical elements of mechanics

    CERN Document Server

    Kane, Thomas R

    2013-01-01

    Analytical Elements of Mechanics, Volume 1, is the first of two volumes intended for use in courses in classical mechanics. The books aim to provide students and teachers with a text consistent in content and format with the author's ideas regarding the subject matter and teaching of mechanics, and to disseminate these ideas. The book opens with a detailed exposition of vector algebra, and no prior knowledge of this subject is required. This is followed by a chapter on the topic of mass centers, which is presented as a logical extension of concepts introduced in connection with centroids. A

  1. Improved nuclear fuel element

    International Nuclear Information System (INIS)

    Klepfer, H.H.

    1974-01-01

    A nuclear fuel element is described which comprises: 1) an elongated clad container, 2) a layer of high lubricity material being disposed in and adjacent to the clad container, 3) a low neutron capture cross section metal liner being disposed in the clad container and adjacent to the layer, 4) a central core of a body of nuclear fuel material disposed in and partially filling the container and forming an internal cavity in the container, 5) an enclosure integrally secured and sealed at each end of the container, and a nuclear fuel material retaining means positioned in the cavity. (author)

  2. Elements of real analysis

    CERN Document Server

    Sprecher, David A

    2010-01-01

    This classic text in introductory analysis delineates and explores the intermediate steps between the basics of calculus and the ultimate stage of mathematics: abstraction and generalization.Since many abstractions and generalizations originate with the real line, the author has made it the unifying theme of the text, constructing the real number system from the point of view of a Cauchy sequence (a step which Dr. Sprecher feels is essential to learn what the real number system is).The material covered in Elements of Real Analysis should be accessible to those who have completed a course in

  3. Nuclear reactor fuel elements

    International Nuclear Information System (INIS)

    Hindle, E. D.

    1984-01-01

    An array of rods is assembled to form a fuel element for a pressurized water reactor, the rods comprising zirconium alloy sheathed nuclear fuel pellets and containing helium. The helium gas pressure is selected for each rod so that it differs substantially from the helium gas pressure in its closest neighbors. In a preferred arrangement the rods are arranged in a square lattice and the helium gas pressure alternates between a relatively high value and a relatively low value so that each rod has as its closest neighbors up to four rods containing helium gas at the other pressure value

  4. Nuclear reactor fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Hindle, E. D.

    1984-10-16

    An array of rods is assembled to form a fuel element for a pressurized water reactor, the rods comprising zirconium alloy sheathed nuclear fuel pellets and containing helium. The helium gas pressure is selected for each rod so that it differs substantially from the helium gas pressure in its closest neighbors. In a preferred arrangement the rods are arranged in a square lattice and the helium gas pressure alternates between a relatively high value and a relatively low value so that each rod has as its closest neighbors up to four rods containing helium gas at the other pressure value.

  5. Osteoporosis and trace elements

    DEFF Research Database (Denmark)

    Aaseth, J.; Boivin, G.; Andersen, Ole

    2012-01-01

    More than 200 million people are affected by osteoporosis worldwide, as estimated by 2 million annual hip fractures and other debilitating bone fractures (vertebrae compression and Colles' fractures). Osteoporosis is a multi-factorial disease with potential contributions from genetic, endocrine...... in new bone and results in a net gain in bone mass, but may be associated with a tissue of poor quality. Aluminum induces impairment of bone formation. Gallium and cadmium suppresses bone turnover. However, exact involvements of the trace elements in osteoporosis have not yet been fully clarified...

  6. [Healthcare marketing elements].

    Science.gov (United States)

    Ameri, Cinzia; Fiorini, Fulvio

    2014-01-01

    Marketing puts its foundation on a few key concepts: need-demand, product-service, satisfaction, exchange, market, or business structure manufacturing / supply. The combination of these elements allows you to build an effective marketing strategy. Crucial in this respect is to remember the Porter matrix, which shows that for a correct analysis of the relevant market is necessary to refer to the "five forces at play", ie: customers, competitors, new entrants and substitutes threat. Another key lever for proper marketing oriented approach is the continuous and constant monitoring of the application, anticipating their dissatisfactions.

  7. Technical Elements (CCT1)

    DEFF Research Database (Denmark)

    Thomsen, Kirsten Engelund; Wittchen, Kim Bjarne

    2017-01-01

    Many of the aspects dealt with in the CA EPBD are closely interlinked with each other and may refer to both new and existing buildings, as well as to inspection and certification. This is also true for technical aspects, such as the calculation methodologies, and how to include technical systems......’ efficiency or how to integrate renewable energy within them. The central team for Technical Elements deals with issues of a technical nature, which are common to new and existing buildings, and/or with minimum demands, certification and inspection. This report focuses on the implementation of Articles 3, 4...

  8. Optical Finite Element Processor

    Science.gov (United States)

    Casasent, David; Taylor, Bradley K.

    1986-01-01

    A new high-accuracy optical linear algebra processor (OLAP) with many advantageous features is described. It achieves floating point accuracy, handles bipolar data by sign-magnitude representation, performs LU decomposition using only one channel, easily partitions and considers data flow. A new application (finite element (FE) structural analysis) for OLAPs is introduced and the results of a case study presented. Error sources in encoded OLAPs are addressed for the first time. Their modeling and simulation are discussed and quantitative data are presented. Dominant error sources and the effects of composite error sources are analyzed.

  9. Elements of energy conversion

    CERN Document Server

    Russell, Charles R

    2013-01-01

    Elements of Energy Conversion brings together scattered information on the subject of energy conversion and presents it in terms of the fundamental thermodynamics that apply to energy conversion by any process. Emphasis is given to the development of the theory of heat engines because these are and will remain most important power sources. Descriptive material is then presented to provide elementary information on all important energy conversion devices. The book contains 10 chapters and opens with a discussion of forms of energy, energy sources and storage, and energy conversion. This is foll

  10. Spectroscopic studies of the transplutonium elements

    International Nuclear Information System (INIS)

    Carnall, W.T.; Conway, J.G.

    1983-01-01

    The challenging opportunity to develop insights into both atomic structure and the effects of bonding in compounds makes the study of actinide spectroscopy a particularly fruitful and exciting area of scientific endeavor. It is also the interpretation of f-element spectra that has stimulated the development of the most sophisticated theoretical modeling attempted for any elements in the periodic table. The unique nature of the spectra and the wealth of fine detail revealed make possible sensitive tests of both physical models and the results of Hartree-Fock type ab initio calculations. This paper focuses on the unique character of heavy actinide spectroscopy. It discusses how it differs from that of the lighter member of the series and what are the special properties that are manifested. Following the introduction, the paper covers the following: (1) the role of systematic studies and the relationships of heavy-actinide spectroscopy to ongoing spectroscopic investigations of the lighter members of the series; (2) atomic (free-ion) spectra which covers the present status of spectroscopic studies with transplutonium elements, and future needs and directions in atomic spectroscopy; (3) the spectra of actinide compounds which covers the present status and future directions of spectroscopic studies with compounds of the transplutonium elements; and other spectroscopies. 1 figure, 2 tables

  11. Finite element analysis of human joints

    Energy Technology Data Exchange (ETDEWEB)

    Bossart, P.L.; Hollerbach, K.

    1996-09-01

    Our work focuses on the development of finite element models (FEMs) that describe the biomechanics of human joints. Finite element modeling is becoming a standard tool in industrial applications. In highly complex problems such as those found in biomechanics research, however, the full potential of FEMs is just beginning to be explored, due to the absence of precise, high resolution medical data and the difficulties encountered in converting these enormous datasets into a form that is usable in FEMs. With increasing computing speed and memory available, it is now feasible to address these challenges. We address the first by acquiring data with a high resolution C-ray CT scanner and the latter by developing semi-automated method for generating the volumetric meshes used in the FEM. Issues related to tomographic reconstruction, volume segmentation, the use of extracted surfaces to generate volumetric hexahedral meshes, and applications of the FEM are described.

  12. Complete Subsurface Elemental Composition Measurements With PING

    Science.gov (United States)

    Parsons, A. M.

    2012-01-01

    The Probing In situ with Neutrons and Gamma rays (PING) instrument will measure the complete bulk elemental composition of the subsurface of Mars as well as any other solid planetary body. PING can thus be a highly effective tool for both detailed local geochemistry science investigations and precision measurements of Mars subsurface reSOurces in preparation for future human exploration. As such, PING is thus fully capable of meeting a majority of both ncar and far term elements in Challenge #1 presented for this conference. Measuring the ncar subsurface composition of Mars will enable many of the MEPAG science goals and will be key to filling an important Strategic Knowledge Gap with regard to In situ Resources Utilization (ISRU) needs for human exploration. [1, 2] PING will thus fill an important niche in the Mars Exploration Program.

  13. Finite element analysis of human joints

    International Nuclear Information System (INIS)

    Bossart, P.L.; Hollerbach, K.

    1996-09-01

    Our work focuses on the development of finite element models (FEMs) that describe the biomechanics of human joints. Finite element modeling is becoming a standard tool in industrial applications. In highly complex problems such as those found in biomechanics research, however, the full potential of FEMs is just beginning to be explored, due to the absence of precise, high resolution medical data and the difficulties encountered in converting these enormous datasets into a form that is usable in FEMs. With increasing computing speed and memory available, it is now feasible to address these challenges. We address the first by acquiring data with a high resolution C-ray CT scanner and the latter by developing semi-automated method for generating the volumetric meshes used in the FEM. Issues related to tomographic reconstruction, volume segmentation, the use of extracted surfaces to generate volumetric hexahedral meshes, and applications of the FEM are described

  14. CULTURAL POLICY IN TRANSITIONAL ECONOMIES: NEW CHALLENGES

    Directory of Open Access Journals (Sweden)

    Ulyana V. SHCHURKO

    2014-06-01

    Full Text Available The article is dedicated to the new conditions of countries’ development in the post-crisis period. Challenges to the cultural and socio-economic policy during last decade were analyzed. Religious factors are offered to be considered as important mechanisms of solving transition period problems, and at the same time as the causes of many conflicts in the world. It was offered to include those factors as inevitable elements into modern policy making process.

  15. Knowledge Management: Trends and Challenges

    Directory of Open Access Journals (Sweden)

    Ljubo Đula

    2010-07-01

    Full Text Available The main theme of this paper is based on the principle goal of the European Union, which is “to become the most competitive and dynamic knowledge-based economy in the world, capable of sustainable economic growth with more and better jobs and greater social cohesion”. The competitive advantage of the “new economy” has been transferred from material and financial resources to non-material and non-financial goods. The crucial challenge for the 21st century company is defining, evaluating, improving, appraisal and management of knowledge. Intellectual capital is the fundamental lever, the basic resource, the underlying potential, the underlying factor of all the elements, i.e. of the business system vertically. Special attention is paid to the intellectual capital as the synergy element of the business system, which can bring about vertical integration. Every company has at its disposal knowledge, abilities, values and recognisability that can be turned into value. If managing with that resource can contribute to a competitive advantage, productivity increase and market value increase, then it is no longer a choice, but a necessity. Because of that, the question is not whether it is necessary to manage intellectual capital, but how to do it.

  16. Nuclear fuel element

    International Nuclear Information System (INIS)

    Iwano, Yoshihiko.

    1993-01-01

    Microfine cracks having a depth of less than 10% of a pipe thickness are disposed radially from a central axis each at an interval of less than 100 micron over the entire inner circumferential surface of a zirconium alloy fuel cladding tube. For manufacturing such a nuclear fuel element, the inside of the cladding tube is at first filled with an electrolyte solution of potassium chloride. Then, electrolysis is conducted using the cladding tube as an anode and the electrolyte solution as a cathode, and the inner surface of the cladding tube with a zirconium dioxide layer having a predetermined thickness. Subsequently, the cladding tube is laid on a smooth steel plate and lightly compressed by other smooth steel plate to form microfine cracks in the zirconium dioxide layer on the inner surface of the cladding tube. Such a compressing operation is continuously applied to the cladding tube while rotating the cladding tube. This can inhibit progress of cracks on the inner surface of the cladding tube, thereby enabling to prevent failure of the cladding tube even if a pellet/cladding tube mechanical interaction is applied. Accordingly, reliability of the nuclear fuel elements is improved. (I.N.)

  17. Heavy-element nucleosynthesis

    International Nuclear Information System (INIS)

    Mathews, G.J.

    1990-01-01

    New measurements and theoretical studies of nuclear properties, together with new astronomical data on the growth of heavy-element abundances during the early history of the Galaxy, now provide a clearer picture of where in nature the elements heavier than iron are produced by rapid (r-process) and show (s-process) neutron capture reactions. The nuclear data suggest that the r-process involves a high-neutron-density beta-flow equilibrium environment and that the s-process may have occurred at a temperature and neutron density consistent with a 13 C(α,n) 16 0 neutron source. The astronomical data, when compared with simple galactic chemical evolution modes, suggests that the r-process is associated with type II supernovae and that the neutron source must be manufactured by the star. Low-mass type II supernovae are proposed as the most important contributors to the r-process. A 13 C neutron source in intermediate-mass stars is proposed for the s-process. 64 refs., 7 figs

  18. Improved nuclear fuel element

    International Nuclear Information System (INIS)

    1980-01-01

    The invention is of a nuclear fuel element which comprises a central core of a body of nuclear fuel material selected from the group consisting of compounds of uranium, plutonium, thorium and mixtures thereof, and an elongated composite cladding container comprising a zirconium alloy tube containing constituents other than zirconium in an amount greater than about 5000 parts per million by weight and an undeformed metal barrier of moderate purity zirconium bonded to the inside surface of the alloy tube. The container encloses the core so as to leave a gap between the container and the core during use in a nuclear reactor. The metal barrier is of moderate purity zirconium with an impurity level on a weight basis of at least 1000ppm and less than 5000ppm. Impurity levels of specific elements are given. Variations of the invention are also specified. The composite cladding reduces chemical interaction, minimizes localized stress and strain corrosion and reduces the likelihood of a splitting failure in the zirconium alloy tube. Other benefits are claimed. (U.K.)

  19. Making visible the unseen elements of nursing.

    Science.gov (United States)

    Allen, Davina

    The traditional image of nurses as caregivers needs revision but this is challenging as much nursing work cannot easily be explained. This article summarises the main findings from a large-scale study of a relatively invisible, but everyday, element of nursing practice--"organising work". This has always been a component of nursing but has recently been seen as a distraction from patient care. More must be done to recognise and communicate its value and the demands it places on staff to shape education, professional development and how nurses are viewed.

  20. Using Hadoop as a grid storage element

    International Nuclear Information System (INIS)

    Bockelman, Brian

    2009-01-01

    Hadoop is an open-source data processing framework that includes a scalable, fault-tolerant distributed file system, HDFS. Although HDFS was designed to work in conjunction with Hadoop's job scheduler, we have re-purposed it to serve as a grid storage element by adding GridFTP and SRM servers. We have tested the system thoroughly in order to understand its scalability and fault tolerance. The turn-on of the Large Hadron Collider (LHC) in 2009 poses a significant data management and storage challenge; we have been working to introduce HDFS as a solution for data storage for one LHC experiment, the Compact Muon Solenoid (CMS).

  1. Modular arrangement of regulatory RNA elements.

    Science.gov (United States)

    Roßmanith, Johanna; Narberhaus, Franz

    2017-03-04

    Due to their simple architecture and control mechanism, regulatory RNA modules are attractive building blocks in synthetic biology. This is especially true for riboswitches, which are natural ligand-binding regulators of gene expression. The discovery of various tandem riboswitches inspired the design of combined RNA modules with activities not yet found in nature. Riboswitches were placed in tandem or in combination with a ribozyme or temperature-responsive RNA thermometer resulting in new functionalities. Here, we compare natural examples of tandem riboswitches with recently designed artificial RNA regulators suggesting substantial modularity of regulatory RNA elements. Challenges associated with modular RNA design are discussed.

  2. First Aid Challenge

    Science.gov (United States)

    Roman, Harry T.

    2011-01-01

    This article describes a challenge wherein students will be asked to design a portable first aid kit that is normally carried in a recreational vehicle (RV), but can also be hand-carried or backpacked off road for distances of approximately 1-2 miles. This can be a very practical challenge for the students because it touches everyone. Everybody…

  3. Virtual Bridge Design Challenge

    Science.gov (United States)

    Mitts, Charles R.

    2013-01-01

    This design/problem-solving activity challenges students to design a replacement bridge for one that has been designated as either structurally deficient or functionally obsolete. The Aycock MS Technology/STEM Magnet Program Virtual Bridge Design Challenge is an authentic introduction to the engineering design process. It is a socially relevant…

  4. Dewey's Challenge to Teachers

    Science.gov (United States)

    Fishman, Stephen M.; McCarthy, Lucille

    2010-01-01

    Given the serious social problems confronting Americans and others worldwide, the authors propose that Dewey's 1932 challenge to teachers is worthy of reconsideration by educators at all levels. In times similar to our own, Dewey challenged teachers to cultivate students' capacities to identify their happiness with what they can do to improve the…

  5. Challenges in fingertip replantation.

    Science.gov (United States)

    Kim, Jin-Soo; Yang, Jae-Won; Lee, Dong-Chul; Ki, Sae-Hwi; Roh, Si-Young

    2013-11-01

    Fingertip amputation is a challenging injury to manage. Among various reconstructive procedures, replantation results in superior outcome, but is seldom considered in many institutions. From the identification of vessel ends to reanastomosis of the submillimeter vessels, fingertip's highly specialized anatomy requires technical excellence. By addressing these anatomic challenges, fingertip replantation can be a routine reconstructive option for microvascular surgeons.

  6. Challenges in Fingertip Replantation

    OpenAIRE

    Kim, Jin-Soo; Yang, Jae-Won; Lee, Dong-Chul; Ki, Sae-Hwi; Roh, Si-Young

    2013-01-01

    Fingertip amputation is a challenging injury to manage. Among various reconstructive procedures, replantation results in superior outcome, but is seldom considered in many institutions. From the identification of vessel ends to reanastomosis of the submillimeter vessels, fingertip's highly specialized anatomy requires technical excellence. By addressing these anatomic challenges, fingertip replantation can be a routine reconstructive option for microvascular surgeons.

  7. Challenge and Change

    Science.gov (United States)

    Mehaffy, George L.

    2012-01-01

    In the past twenty years, various industries have been forever altered by technology: newspapers, book publishing, the photography business, and many more. Higher education too faces unprecedented challenges primarily driven by rapid changes in technology. To meet these challenges and adapt to these changes, new models are needed. Six challenges…

  8. Prediction of regulatory elements

    DEFF Research Database (Denmark)

    Sandelin, Albin

    2008-01-01

    Finding the regulatory mechanisms responsible for gene expression remains one of the most important challenges for biomedical research. A major focus in cellular biology is to find functional transcription factor binding sites (TFBS) responsible for the regulation of a downstream gene. As wet......-lab methods are time consuming and expensive, it is not realistic to identify TFBS for all uncharacterized genes in the genome by purely experimental means. Computational methods aimed at predicting potential regulatory regions can increase the efficiency of wet-lab experiments significantly. Here, methods...

  9. NIH Common Data Elements Repository

    Data.gov (United States)

    U.S. Department of Health & Human Services — The NIH Common Data Elements (CDE) Repository has been designed to provide access to structured human and machine-readable definitions of data elements that have...

  10. Employment challenges in the future

    DEFF Research Database (Denmark)

    2011-01-01

    Discussion of challenges in employment challenges in Europe and a brief discription of the Danish flexicurity system......Discussion of challenges in employment challenges in Europe and a brief discription of the Danish flexicurity system...

  11. Joining elements of silicon carbide

    International Nuclear Information System (INIS)

    Olson, B.A.

    1979-01-01

    A method of joining together at least two silicon carbide elements (e.g.in forming a heat exchanger) is described, comprising subjecting to sufficiently non-oxidizing atmosphere and sufficiently high temperature, material placed in space between the elements. The material consists of silicon carbide particles, carbon and/or a precursor of carbon, and silicon, such that it forms a joint joining together at least two silicon carbide elements. At least one of the elements may contain silicon. (author)

  12. Trace element emissions from coal

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-09-15

    Trace elements are emitted during coal combustion. The quantity, in general, depends on the physical and chemical properties of the element itself, the concentration of the element in the coal, the combustion conditions and the type of particulate control device used, and its collection efficiency as a function of particle size. Some trace elements become concentrated in certain particle streams following combustion such as bottom ash, fly ash, and flue gas particulate matter, while others do not. Various classification schemes have been developed to describe this partitioning behaviour. These classification schemes generally distinguish between: Class 1: elements that are approximately equally concentrated in the fly ash and bottom ash, or show little or no fine particle enrichment, examples include Mn, Be, Co and Cr; Class 2: elements that are enriched in the fly ash relative to bottom ash, or show increasing enrichment with decreasing particle size, examples include As, Cd, Pb and Sb; Class 3: elements which are emitted in the gas phase (primarily Hg (not discussed in this review), and in some cases, Se). Control of class 1 trace elements is directly related to control of total particulate matter emissions, while control of the class 2 elements depends on collection of fine particulates. Due to the variability in particulate control device efficiencies, emission rates of these elements can vary substantially. The volatility of class 3 elements means that particulate controls have only a limited impact on the emissions of these elements.

  13. REACTOR FUEL ELEMENTS TESTING CONTAINER

    Science.gov (United States)

    Whitham, G.K.; Smith, R.R.

    1963-01-15

    This patent shows a method for detecting leaks in jacketed fuel elements. The element is placed in a sealed tank within a nuclear reactor, and, while the reactor operates, the element is sparged with gas. The gas is then led outside the reactor and monitored for radioactive Xe or Kr. (AEC)

  14. Accelerator vacuum system elements

    International Nuclear Information System (INIS)

    Sivokon', V.V.; Kobets, A.F.; Shvetsov, V.A.; Sivokon', L.V.

    1980-01-01

    Some elements of vacuum systems are investigated. Considerable attention has been given to the investigation into peculiarities in pumping out of a ionoguide for transportation of an accelerated charged particles beam the spread of which often attains a considerable length. The number of pumps over the ionoguide length is experimentally determined. It is shown that as a result of ionoguide warm-up the pumping out time is considerably reduced maximum permissible pressure is decreased by two orders and lesser rate of pump pumping out is required. The investigations have shown that when operating the ionoguide there is no necessity in setting up seals between the ionoguide and magnetodischarged pump. The causes of the phenomenon in which the pressure near the pump is greater than in the end of the ionoguide, are impurities carried in by the pump into the ionoguide volume and the pumping out capacity of the pressure converter

  15. Ucla, escuela elemental

    Directory of Open Access Journals (Sweden)

    Neutra, Richard J.

    1962-03-01

    Full Text Available La Escuela Elemental de Preparación de la Universidad de California, en Los Angeles, está dedicada a la educación e investigación y preparación del profesorado de la infancia. Se ha construido en un paraje maravilloso, de frondosa vegetación, frente a un terreno bastante quebrado, circunstancia que presta mayor encanto al conjunto, construido con gran pericia y adaptación al paisaje a base de una dominante horizontalidad, con materiales sencillos (ladrillos, hierro y madera y gran comunicación con la naturaleza mediante grandes cristaleras correderas que ensanchan las clases y las suplementan hacia el jardín de acuerdo con las nuevas normas y prácticas docentes.

  16. Improved nuclear fuel element

    International Nuclear Information System (INIS)

    1974-01-01

    A nuclear fuel element for use in the core of a nuclear reactor is disclosed and has a metal liner disposed between the cladding and the nuclear fuel material and a high lubricity material in the form of a coating disposed between the liner and the cladding. The liner preferably has a thickness greater than the longest fission product recoil distance and is composed of a low neutron capture cross-section material. The liner is preferably composed of zirconium, an alloy of zirconium, niobium or an alloy of niobium. The liner serves as a preferential reaction site for volatile impurities and fission products and protects the cladding from contact and reaction with such impurities and fission products. The high lubricity material acts as an interface between the liner and the cladding and reduces localized stresses on the cladding due to fuel expansion and cracking of the fuel

  17. Probabilistic fracture finite elements

    Science.gov (United States)

    Liu, W. K.; Belytschko, T.; Lua, Y. J.

    1991-05-01

    The Probabilistic Fracture Mechanics (PFM) is a promising method for estimating the fatigue life and inspection cycles for mechanical and structural components. The Probability Finite Element Method (PFEM), which is based on second moment analysis, has proved to be a promising, practical approach to handle problems with uncertainties. As the PFEM provides a powerful computational tool to determine first and second moment of random parameters, the second moment reliability method can be easily combined with PFEM to obtain measures of the reliability of the structural system. The method is also being applied to fatigue crack growth. Uncertainties in the material properties of advanced materials such as polycrystalline alloys, ceramics, and composites are commonly observed from experimental tests. This is mainly attributed to intrinsic microcracks, which are randomly distributed as a result of the applied load and the residual stress.

  18. Nuclear fuel elements

    International Nuclear Information System (INIS)

    Obara, Hiroshi.

    1981-01-01

    Purpose: To suppress iodine release thereby prevent stress corrosion cracks in fuel cans by dispersing ferrous oxide at the outer periphery of sintered uranium dioxide pellets filled and sealed within zirconium alloy fuel cans of fuel elements. Constitution: Sintered uranium dioxide pellets to be filled and sealed within a zirconium alloy fuel can are prepared either by mixing ferric oxide powder in uranium dioxide powder, sintering and then reducing at low temperature or by mixing iron powder in uranium dioxide powder, sintering and then oxidizing at low temperature. In this way, ferrous oxide is dispersed on the outer periphery of the sintered uranium dioxide pellets to convert corrosive fission products iodine into iron iodide, whereby the iodine release is suppressed and the stress corrosion cracks can be prevented in the fuel can. (Moriyama, K.)

  19. Nuclear fuel element

    International Nuclear Information System (INIS)

    Hirama, H.

    1978-01-01

    A nuclear fuel element comprises an elongated tube having upper and lower end plugs fixed to both ends thereof and nuclear fuel pellets contained within the tube. The fuel pellets are held against the lower end plug by a spring which is supported by a setting structure. The setting structure is maintained at a proper position at the middle of the tube by a wedge effect caused by spring force exerted by the spring against a set of balls coacting with a tapered member of the setting structure thereby wedging the balls against the inner wall of the tube, and the setting structure is moved free by pushing with a push bar against the spring force so as to release the wedge effect

  20. Finite element modelling

    International Nuclear Information System (INIS)

    Tonks, M.R.; Williamson, R.; Masson, R.

    2015-01-01

    The Finite Element Method (FEM) is a numerical technique for finding approximate solutions to boundary value problems. While FEM is commonly used to solve solid mechanics equations, it can be applied to a large range of BVPs from many different fields. FEM has been used for reactor fuels modelling for many years. It is most often used for fuel performance modelling at the pellet and pin scale, however, it has also been used to investigate properties of the fuel material, such as thermal conductivity and fission gas release. Recently, the United Stated Department Nuclear Energy Advanced Modelling and Simulation Program has begun using FEM as the basis of the MOOSE-BISON-MARMOT Project that is developing a multi-dimensional, multi-physics fuel performance capability that is massively parallel and will use multi-scale material models to provide a truly predictive modelling capability. (authors)

  1. Heavy-element research

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    The status is reported of studies on the solid-state chemistry of the actinides and lanthanides, spectroscopy of actinide compounds, and dynamic chemical description of actinide elements in solution. Phase studies were done on Rb 2 UO 4 , K 2 UO 4 , Li 2 UO 4 , and Es 2 U 2 O 7 . The lithium neptunate (VI) system was investigated and the existence of Li 2 NpO 4 was established. In oxidation-reduction studies it was shown that Am(III) can be electrolytically oxidized to Am(IV) in strong H 3 PO 4 , but Cf(III) and Pr(III) do not oxidize. The low-temperature absorption spectrum of thin films of NpBr 3 was investigated. (U.S.)

  2. ELEMENTAL FORMS OF HOSPITALITY

    Directory of Open Access Journals (Sweden)

    Maximiliano Emanuel Korstanje

    2010-11-01

    Full Text Available Modern studies emphasized on the needs of researching the hospitality as relevant aspects of tourism and hospitality fields. Anyway, these approaches are inextricably intertwined to the industry of tourism and do not take seriously the anthropological and sociological roots of hospitality. In fact, the hotel seems to be a partial sphere of hospitality at all. Under this context, the present paper explores the issue of hospitality enrooted in the political and economic indo-European principle of free-transit which is associated to a much broader origin.  Starting from the premise etymologically hostel and hospital share similar origins, we follow the contributions of J Derrida to determine the elements that formed the hospitality up to date.

  3. Photo-switching element

    Energy Technology Data Exchange (ETDEWEB)

    Masaki, Yuichi

    1987-10-31

    Photo-input MOS transistor (Photo-switching element) cannot give enough ON/OFF ratio but requires an auxiliary condenser for a certain type of application. In addition, PN junction of amorphous silicon is not practical because it gives high leak current resulting in low electromotive force. In this invention, a solar cell was constructed with a lower electrode consisting of a transparent electro-conducting film, a photosensitive part consisting of an amorphous Si layer of p-i-n layer construction, and an upper metal electrode consisting of Cr or Nichrome, and a thin film transistor was placed on the solar cell, and further the upper metal electrode was co-used as a gate electrode of the thin film transistor; this set-up of this invention enabled to attain an efficient photo-electric conversion of the incident light, high electromotive force of the solar cell, and the transistor with high ON/OFF ratio. (3 figs)

  4. Human missions to Mars: issues and challenges

    Science.gov (United States)

    Race, M.; Kminek, G.

    Recent announcements of the planned future human exploration of Mars by both European and US space agencies have raised a host of questions and challenges that must be addressed in advance of long-duration human missions. While detailed mission planning is a long way off, numerous issues can already be identified in the broad context of planetary protection. In this session, a panel of experts will provide brief overviews of the types of challenges ahead, such as the protection of the martian environment; the integration of human and robotic mission elements and operations; precursor scientific information necessary to plan human missions; development and use of nuclear and other technologies for the protection and support of astronauts during the mission; protection of Earth upon return; and societal and ethical questions about human exploration. The session has been designed to encourage and incorporate audience participation in the discussion about the issues and challenges ahead.

  5. Big Data Challenges

    Directory of Open Access Journals (Sweden)

    Alexandru Adrian TOLE

    2013-10-01

    Full Text Available The amount of data that is traveling across the internet today, not only that is large, but is complex as well. Companies, institutions, healthcare system etc., all of them use piles of data which are further used for creating reports in order to ensure continuity regarding the services that they have to offer. The process behind the results that these entities requests represents a challenge for software developers and companies that provide IT infrastructure. The challenge is how to manipulate an impressive volume of data that has to be securely delivered through the internet and reach its destination intact. This paper treats the challenges that Big Data creates.

  6. The challenges of dismantling

    International Nuclear Information System (INIS)

    Sene, Monique; Lheureux, Yves; Leroyer, Veronique; Rollinger, Francois; Gauthier, Florence; Depauw, Denis; Reynal, Nathalie; Fraysse, Thierry; Burger, Eric; Bertrand, Adrien; Vallat, Christophe; Bernet, Philippe; Eimer, Michel; Boutin, Dominique; Bietrix, Philippe; Richard, Francoise; Piketty, Laurence; Mouchet, Chantal; Charre, Jean-Pierre

    2014-01-01

    This document gathers Power Point presentations which address the contexts and challenges of dismantling (legal framework, safety and radiation protection challenges, waste processing industry), and propose illustrations of dismantling challenges (example of operations to prepare EURODIF dismantling and CLIGEET work-group on EURODIF dismantling, examples of dismantling of EDF installations and CLIs' opinion on the dismantling of EDF installations, Brennilis dismantling follow-up performed by the CLI, examples of dismantling of CEA installations and opinion of a CLI on the dismantling of CEA installations)

  7. Challenges of serious games

    Directory of Open Access Journals (Sweden)

    B. Fernández-Manjón

    2015-11-01

    Full Text Available Although educational games have revealed to be a very effective focus in diverse situations, their use in education is still very limited. In this paper we analyse the main challenges concerning educational games that, from our perspective, have to be approached so that the use of this kind of games can be widespread. These challenges are classified in three main dimensions: socio-cultural, educational and technological. Once the challenges are identified, some possible measures are suggested to address or reduce these problems so that the use of educational games may be widespread.

  8. Transplutonium elements - a literature survey

    International Nuclear Information System (INIS)

    Sivaramakrishnan, C.K.; Jadhav, A.V.

    1974-01-01

    The report surveys reported work on the discovery of transplutonium elements and their production through various methods like bombardment of heavy elements with charged ions, successive neutron captures on heavy elements in reactors and multiple neutron captures by heavy elements during nuclear explosions. Estimated yields of transplutonium elements in special targets irradiated in reactors, and also as byproducts from spent power reactor fuels are quoted. Various chemical procedures adopted for recovery of these elements from irradiated target and also from power reactor fuel reprocessing streams are described. A brief survey of shielded facilities available at various centres for transplutonium programmes is also included. Major uses of some of these heavy elements are described. (author)

  9. Predicting the Remaining Useful Life of Rolling Element Bearings

    DEFF Research Database (Denmark)

    Hooghoudt, Jan Otto; Jantunen, E; Yi, Yang

    2018-01-01

    Condition monitoring of rolling element bearings is of vital importance in order to keep the industrial wheels running. In wind industry this is especially important due to the challenges in practical maintenance. The paper presents an attempt to improve the capability of prediction of remaining...

  10. Anthropocene Age Wicked Challenges

    DEFF Research Database (Denmark)

    Edgeman, Rick; Wu, Zhaohui

    2015-01-01

    weather events, drought, and desertification; threatened food supplies; water pollution, air pollution, and soil contamination; and the connection of these to disease, violence, and terrorism. Wicked challenges are discussed in relation to enterprise excellence, sustainability, resilience and robustness...

  11. Big data challenges

    DEFF Research Database (Denmark)

    Bachlechner, Daniel; Leimbach, Timo

    2016-01-01

    Although reports on big data success stories have been accumulating in the media, most organizations dealing with high-volume, high-velocity and high-variety information assets still face challenges. Only a thorough understanding of these challenges puts organizations into a position in which...... they can make an informed decision for or against big data, and, if the decision is positive, overcome the challenges smoothly. The combination of a series of interviews with leading experts from enterprises, associations and research institutions, and focused literature reviews allowed not only...... framework are also relevant. For large enterprises and startups specialized in big data, it is typically easier to overcome the challenges than it is for other enterprises and public administration bodies....

  12. Space Robotics Challenge

    Data.gov (United States)

    National Aeronautics and Space Administration — The Space Robotics Challenge seeks to infuse robot autonomy from the best and brightest research groups in the robotics community into NASA robots for future...

  13. The Electric Car Challenge.

    Science.gov (United States)

    Diehl, Brian E.

    1997-01-01

    Describes the Electric Car Challenge during which students applied methods of construction to build lightweight, strong vehicles that were powered by electricity. The activity required problem solving, sheet metal work, electricity, design, and construction skills. (JOW)

  14. Challenges to Public Health

    Indian Academy of Sciences (India)

    First page Back Continue Last page Graphics. Challenges to Public Health. Tracing of the infection. Isolation of patients to stop spread. Laboratory diagnosis. Hospitalization &Treatment. Stock pile & supply of drugs. Planning & mitigation. Information to public. Support to SEARO countries.

  15. Community Challenge Grantees

    Data.gov (United States)

    Department of Housing and Urban Development — HUD's Community Challenge Grants aim to reform and reduce barriers to achieving affordable, economically vital and sustainable communities. The funds are awarded to...

  16. Brazil World Cup Challenges

    Directory of Open Access Journals (Sweden)

    MANSUR, R.

    2012-12-01

    Full Text Available Overcoming the productivity challenge is the main benefit of the 2014 World Cup for Brazilian people. The sustainable development of our cultural tourism industry will catapult the new middle class growing up rate.

  17. The boomer challenge.

    Science.gov (United States)

    Barr, Paul

    2014-01-01

    Hospitals and the rest of health care will have to make some major adjustments to meet the needs of the aging baby boom generation. The first article in our year-long series inventories the many challenges that lie ahead.

  18. Overcoming Safeguards Challenges

    International Nuclear Information System (INIS)

    Henriques, Sasha

    2011-01-01

    The focus of the 2010 IAEA International Safeguards Symposium was how best, from a technical perspective, to prepare for future verification challenges during this time of change. By bringing together the leading experts in the field from across the world, this symposium provided an opportunity for stakeholders to explore possible solutions in support of the IAEA's nuclear verification mission, and to identify areas where the different stakeholders in the safeguards business can help address these challenges

  19. Challenges in obesity research

    OpenAIRE

    Palou, Andreu; Bonet, M. Luisa

    2013-01-01

    Obesity is the main nutritional problem and one of the most important health problems in developed societies. Central to the challenge of obesity prevention and management is a thoroughly understanding of its determinants. Multiple socio-cultural, socio-economic, behavioural and biological factors -often interrelated and many of them still unknown or poorly understood- can contribute to the establishment and perpetuation of obese phenotypes. Here, we address current research challenges regard...

  20. EAF optimal managing elements

    Science.gov (United States)

    Ioana, A.; Constantin, N.; Dragna, E. C.

    2017-01-01

    Electric Arc Furnaces (EAF) is an important and complex aggregate. We present elements of EAF operating efficiency. The reliability of the EAF is mainly determined by electric circuit reliability and especially of the transformator of the furnace. This due to the fact that, in an electric steel plant, the objective „24 tapping/day” involves. Due to the complexity of the process, the EAF operation needs a computer usage and, in his componence, it must have two independent calculation units (UC1) and (UC2). Based on these two input sets (Σi1) and ((Σi2), the calculation unit (UC1) builds the general operation procedure based on mathematical methods. For that purpose, there are used the results of the 5 mathematical methods: the mathematical model to write-off the function objective (M.F.O.); the mathematical model of calculating the charge (M.C.C.); the mathematical model of conducting the effective melt (M.C.M.); the mathematical model of reheating the charge (M.R.C.); the mathematical model of blasting the reactive dusts (M.B.R.D.).

  1. Nuclear fuel element

    International Nuclear Information System (INIS)

    Armijo, J.S.

    1977-01-01

    A nuclear fuel element for use in the core of a nuclear reactor is disclosed which has a composite cladding having a substrate, a metal barrier metallurgically bonded to the inside surface of the substrate and an inner layer metallurgically bonded to the inside surface of the metal barrier. In this composite cladding, the inner layer and the metal barrier shield the substrate from any impurities or fission products from the nuclear fuel material held within the composite cladding. The metal barrier forms about 1 to about 4 percent of the thickness of the cladding and is comprised of a metal selected from the group consisting of niobium, aluminum, copper, nickel, stainless steel, and iron. The inner layer and then the metal barrier serve as reaction sites for volatile impurities and fission products and protect the substrate from contact and reaction with such impurities and fission products. The substrate and the inner layer of the composite cladding are selected from conventional cladding materials and preferably are a zirconium alloy. Also in a preferred embodiment the substrate and the inner layer are comprised of the same material, preferably a zirconium alloy. 19 claims, 2 figures

  2. Neutron absorbing element

    International Nuclear Information System (INIS)

    Kasai, Shigeo.

    1991-01-01

    The present invention concerns a neutron absorbing element of a neutron shielding member used for an LMFBR type reactor. The inside of a fuel can sealed at both of the upper and the lower ends thereof with plugs is partitioned into an upper and a lower chambers by an intermediate plug. A discharging hole is disposed at the upper end plug, which is in communication with the outside. A communication tube is disposed at the intermediate end plug and it is in communication with the lower chamber containing B 4 C pellets. A cylindrical support member having three porous plugs connected in series is disposed at the lower surface of the discharging hole provided at the upper end plug. Further, the end of the discharging hole is sealed with high temperature solder and He atmosphere is present at the inside of the fuel can. With such a constitution, the supporting differential pressure of the porous plugs can be made greater while discharging He gases generated from B 4 C to the outside. Further, the porous plugs can be surely wetted by coolants. Accordingly, it is possible to increase life time and shorten the size. (I.N.)

  3. Chemistry of transuranium elements

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    The half-wave amalgamation potential of No (element 102) was determined. Studies on the preparation and properties of Cf are reported; previously reported results on Es were confirmed. The heat of solution of Bk was measured. Spectroscopic and x-ray diffraction studies of Es-253 bromides are reported. Salicylate complexes with Sm(III), Am(III), Th(IV), and U(IV)O 2 were prepared; crystal data are given. Results of studies on the effect of secondary bonds on the strength of O double bond Np double bond O bonds are reported. The M series x rays of Np were measured. Anomalous spin--orbit splitting of the 4f level in the actinide series is reported. Progress is reported in studies on the Cf oxide system for oxygen pressures up to 760 mm and temperatures between 25 and 1000 0 C, as well as structural parameters of transplutonium oxysulfates and oxysulfides and actinide and lanthanide hydroxides. The electron paramagnetic resonance spectrum of 253 Es 2+ was observed in the cubic monocrystal hosts BaF 2 and SrCl 2

  4. 77 FR 70835 - Centennial Challenges 2013 Sample Return Robot Challenge

    Science.gov (United States)

    2012-11-27

    ... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Centennial Challenges 2013 Sample Return Robot... Challenge is scheduled and teams that wish to compete may register. Centennial Challenges is a program of... Challenge, please visit: http://challenge.wpi.edu . For general information on the NASA Centennial...

  5. 76 FR 56819 - Centennial Challenges 2012 Sample Return Robot Challenge

    Science.gov (United States)

    2011-09-14

    ... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice (11-079)] Centennial Challenges 2012 Sample... Challenge is scheduled and teams that wish to compete may register. Centennial Challenges is a program of... Challenge, please visit: http://wp.wpi.edu/challenge/ . For general information on the NASA Centennial...

  6. Experimental Study of Elements Promoting Mixing in Fuel Elements

    International Nuclear Information System (INIS)

    Silin, Nicolas; Juanico, Luis; Delmastro, Dario

    2003-01-01

    In the present work a thermal tracing technique is used to measure the increase of the mixing between subchannels in the presence of different mixing elements.As representative elements a spacer, a spacer with mixing vanes and turbulence promoter buttons were considered.The performance of these elements was evaluated by studying the behavior of a thermal trace in each case.Also the pressure drop for each case is presented.The results present a qualitative and quantitative guide for the application of each one of these appendages in future nuclear elements

  7. Testing the ecological consequences of evolutionary change using elements.

    Science.gov (United States)

    Jeyasingh, Punidan D; Cothran, Rickey D; Tobler, Michael

    2014-02-01

    Understanding the ecological consequences of evolutionary change is a central challenge in contemporary biology. We propose a framework based on the ˜25 elements represented in biology, which can serve as a conduit for a general exploration of poorly understood evolution-to-ecology links. In this framework, known as ecological stoichiometry, the quantity of elements in the inorganic realm is a fundamental environment, while the flow of elements from the abiotic to the biotic realm is due to the action of genomes, with the unused elements excreted back into the inorganic realm affecting ecological processes at higher levels of organization. Ecological stoichiometry purposefully assumes distinct elemental composition of species, enabling powerful predictions about the ecological functions of species. However, this assumption results in a simplified view of the evolutionary mechanisms underlying diversification in the elemental composition of species. Recent research indicates substantial intraspecific variation in elemental composition and associated ecological functions such as nutrient excretion. We posit that attention to intraspecific variation in elemental composition will facilitate a synthesis of stoichiometric information in light of population genetics theory for a rigorous exploration of the ecological consequences of evolutionary change.

  8. The elements of relativity

    CERN Document Server

    Wittman, David

    2018-01-01

    Relativity has much to offer for a well-rounded education. Yet books on relativity either assume a strong background in physics and math, aimed at advanced physics students, or, alternatively, offer a broad description with little intellectual challenge. This book bridges the gap. It aims at readers with essentially no physics or math background, who still find it rewarding to think rigorously. The book takes a "thinking tools" approach, by first making readers comfortable with a new thinking tool and then applying it to learn more about how nature works. By the end of the book, readers will have collected a versatile toolbox and will be comfortable using the tools to think about and really understand the intriguing phenomena they may have only heard about, including the twin paradox, black holes, and time travel. End-of-chapter exercises span a range of difficulty, allowing adventurous readers to stretch their understanding further as desired. Students who have studied, or are studying, relativity at a more...

  9. Speciation of trace elements in the environmental studies

    International Nuclear Information System (INIS)

    Reddy, A.V.R.

    2012-01-01

    Elements present at trace levels, often referred as trace elements, play an important role in the environment and in the functioning of life on our planet. Trace elements in environment present as free metal ions or incorporated into colloids or attached to particulate matter or exist in different physical and chemical forms. It is well established that some elements are highly toxic and some are essential, but can become toxic at higher doses. It is also now known that the forms of elements (speciation) and their amounts are more important than the chemical dose of the elements as their interaction depends on different species. For example, Cr(VI) ions are considered far more toxic than Cr(III), whereas As(III) is more toxic than As(V). Similarly, in the case of mercury, both methylmercury and inorganic mercury are toxic but they show different levels of toxicity. Thus the adverse effects depend on the nature of species of the elements and therefore speciation studies are of paramount importance in many areas like toxicology, environmental chemistry and geochemisty. In view of this, speciation studies is a challenge to analytical chemists as the measurement methodologies have to be carefully developed, validated and applied. The grand challenge is to obtain quality data ensuring traceability, as the data obtained will be used in modeling for predicting the environmental impacts. In this talk importance of speciation and challenges to environmental analytical chemists will be discussed along with the following three speciation studies on Cr, U and Hg which were carried out in our laboratories

  10. Finite element simulation of dynamic wetting flows as an interface formation process

    KAUST Repository

    Sprittles, J.E.; Shikhmurzaev, Y.D.

    2013-01-01

    A mathematically challenging model of dynamic wetting as a process of interface formation has been, for the first time, fully incorporated into a numerical code based on the finite element method and applied, as a test case, to the problem

  11. Meeting the inventory optimization challenges of the 1990s

    International Nuclear Information System (INIS)

    Jones, L.K. IV

    1992-01-01

    This paper outlines some of the efforts being taken by the new Southern Nuclear Operating Company to augment the inventory optimization efforts of the parent Southern Company. Southern Nuclear Operating Company's management is undertaking a multifaceted program to enhance their inventory practices. Key elements of this program include improved performance reporting, procurement support, and material identification. These elements will enable Southern Nuclear to meet inventory management challenges dynamically in the 1990s

  12. Analog elements for transuranic chemistries

    International Nuclear Information System (INIS)

    Weimer, W.C.

    1982-01-01

    The analytical technique for measuring trace concentrations of the analog rare earth elements has been refined for optimal detection. The technique has been used to determine the rare earth concentrations in a series of geological and biological materials, including samples harvested from controlled lysimeter investigations. These studies have demonstrated that any of the trivalent rare earth elements may be used as analog elements for the trivalent transuranics, americium and curium

  13. Challenges in obesity research.

    Science.gov (United States)

    Palou, Andreu; Bonet, M Luisa

    2013-09-01

    Obesity is the main nutritional problem and one of the most important health problems in developed societies. Central to the challenge of obesity prevention and management is a thoroughly understanding of its determinants. Multiple socio-cultural, socio-economic, behavioural and biological factors--often interrelated and many of them still unknown or poorly understood--can contribute to the establishment and perpetuation of obese phenotypes. Here, we address current research challenges regarding basic aspects of obesity and emerging science for its control, including brown adipose tissue thermogenesis and browning of white fat as possible therapeutic targets for obesity, the influence of the microbioma, and genetics, epigenetics, nutrigenomics and nutrigenetics of obesity. We also highlight hot topics in relation to food and lifestyle as determinants of obesity, including the brain mechanisms underlying environmental motivation to eat, the biological control of spontaneous physical activity, the possible role of concrete foods and food components, and the importance of early life nutrition and environment. Challenges regarding the connections of obesity with other alterations and pathologies are also briefly addressed, as well as social and economical challenges in relation to healthy food production and lifestyle for the prevention of obesity, and technological challenges in obesity research and management. The objective is to give a panoramic of advances accomplished and still ahead relevant to the different stakeholders engaged in understanding and combating obesity. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

  14. Photoshop Elements 10 For Dummies

    CERN Document Server

    Obermeier, Barbara

    2011-01-01

    Perfect your photos and images with this "focused" guide to the latest version of Photoshop Elements For most of us, the professional-level Photoshop is overkill for our needs. Amateur photographers and photo enthusiasts turn to Photoshop Elements for a powerful but simpler way to edit and retouch their snapshots. Photoshop Elements 10 For Dummies, fully updated and revised for the latest release of this software product, helps you navigate Elements to create, edit, fix, share, and organize the high-quality images you desire. Full color pages bring the techniques to life and make taking great

  15. Global challenges in energy

    International Nuclear Information System (INIS)

    Dorian, James P.; Franssen, Herman T.; Simbeck, Dale R. MD

    2006-01-01

    Environmental and security concerns are stimulating global interest in hydrogen power, renewable energy, and advanced transportation technologies, but no significant movement away from oil and a carbon-based world economy is expected soon. Over the longer-term, however, a transition from fossil fuels to a non-carbon-based economy will likely occur, affecting the type of environment future generations may encounter. Key challenges will face the world's energy industry over the next few decades to ensure a smooth transition-challenges which will require government and industry solutions beginning as early as today. This paper identifies four critical challenges in energy and the choices which will have to be made on how best to confront growing pollution caused by fossil fuels and how to facilitate an eventual revolutionary-like transition to a non-carbon-based global economy

  16. The challenge of sustainability

    International Nuclear Information System (INIS)

    Orr, D.W.

    1993-01-01

    This paper discusses sustainability in a world that has changed rapidly. The author suggests that ecological assumptions embedded in communism and capitalism are badly flawed, but the flaws were not apparent when there were fewer than a billion people on earth living at low technology levels. Sustaining the earth's vital signs is a challenge to our perception of time, and the numbers - population, environmental damage, oil consumption, waste disposal - are too large to comprehend easily. There is a global debate about what sustainability means. In fact the challenge of sustainability is 6 different challenges: overcoming the tendency to deny inconvenient realities; establishing accurate indicators of human and ecological health; questions about the kinds of technology necessary to make the transition to sustainability; education; the need for an emotional bond between man and nature; rebuilding the existing democratic institutions. 16 refs

  17. Centennial Challenges Program

    Science.gov (United States)

    Ortega, Sam; Eberly, Eric

    2015-01-01

    NASA's Centennial Challenges Program was initiated in 2005 to directly engage the public in the process of advanced technology development. The program offers incentive prizes to generate revolutionary solutions to problems of interest to NASA and the nation. The program seeks innovations from diverse and nontraditional sources. Competitors are not supported by government funding and awards are only made to successful teams when the challenges are met. In keeping with the spirit of the Wright Brothers and other American innovators, the Centennial Challenge prizes are offered to independent inventors including small businesses, student groups, and individuals. These independent inventors are sought to generate innovative solutions for technical problems of interest to NASA and the nation and to provide them with the opportunity to stimulate or create new business ventures.

  18. Small finance banks: Challenges

    Directory of Open Access Journals (Sweden)

    Jayadev M

    2017-12-01

    Full Text Available A recent innovation in the Indian banking structure has been the formation of a new banking institution—small finance banks (SFBs. These banks are expected to penetrate into financial inclusion by providing basic banking and credit services with a differentiated banking model to the larger population. In this context the new SFBs have multiple challenges in coming out with a new, differentiated business model. The challenges include building low cost liability portfolio, technology management, and balancing the regulatory compliances. This paper also presents the top of mind views of three senior executives of new small finance banks.

  19. Challenges facing production grids

    Energy Technology Data Exchange (ETDEWEB)

    Pordes, Ruth; /Fermilab

    2007-06-01

    Today's global communities of users expect quality of service from distributed Grid systems equivalent to that their local data centers. This must be coupled to ubiquitous access to the ensemble of processing and storage resources across multiple Grid infrastructures. We are still facing significant challenges in meeting these expectations, especially in the underlying security, a sustainable and successful economic model, and smoothing the boundaries between administrative and technical domains. Using the Open Science Grid as an example, I examine the status and challenges of Grids operating in production today.

  20. The challenge of conceiving

    DEFF Research Database (Denmark)

    Hansen, Claus Thorp; Jørgensen, Ulrik

    2011-01-01

    the perspective of engineering design challenges where the need for problem identification is obvious to avoid the pitfall to reproduce and piecemeal engineer already existing product or service concepts. Problem identification is not a simple desk research task as it often involves a multitude of actors having......One of the big challenges in the CDIO approach to engineering education is the first part focusing on conceiving problems to be handled and eventually solved. Traditional engineering education has been dominated by its focus on technical disciplines emphasising their individual tool box of problem...