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

NASA Astrophysics Data System (ADS)

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.

Assessing theoretical uncertainties in fission barriers of superheavy nuclei

DOE PAGES

Agbemava, S. E.; Afanasjev, A. V.; Ray, D.; ...

2017-05-26

Here, theoretical uncertainties in the predictions of inner fission barrier heights in superheavy elements have been investigated in a systematic way for a set of state-of-the-art covariant energy density functionals which represent major classes of the functionals used in covariant density functional theory. They differ in basic model assumptions and fitting protocols. Both systematic and statistical uncertainties have been quantified where the former turn out to be larger. Systematic uncertainties are substantial in superheavy elements and their behavior as a function of proton and neutron numbers contains a large random component. The benchmarking of the functionals to the experimental datamore » on fission barriers in the actinides allows to reduce the systematic theoretical uncertainties for the inner fission barriers of unknown superheavy elements. However, even then they on average increase on moving away from the region where benchmarking has been performed. In addition, a comparison with the results of non-relativistic approaches is performed in order to define full systematic theoretical uncertainties over the state-of-the-art models. Even for the models benchmarked in the actinides, the difference in the inner fission barrier height of some superheavy elements reaches $5-6$ MeV. This uncertainty in the fission barrier heights will translate into huge (many tens of the orders of magnitude) uncertainties in the spontaneous fission half-lives.« less

Application of the mass-spectrometer MASHA for mass-spectrometry and laser-spectroscopy

NASA Astrophysics Data System (ADS)

Rodin, A. M.; Belozerov, A. V.; Dmitriev, S. N.; Oganessian, Yu. Ts.; Sagaidak, R. N.; Salamatin, V. S.; Stepantsov, S. V.; Vanin, D. V.

2010-02-01

We report the present status of the mass-spectrometer MASHA (Mass-Analyzer of Supper Heavy Atoms) designed for determination of the masses of superheavy elements. The mass-spectrometer is connected to the U-400M cyclotron of the Flerov Laboratory for Nuclear Reactions (FLNR) JINR, Dubna. The first experiments on mass-measurements for 112 and 114 elements will be performed in the upcoming 2010. For this purpose a hot catcher, based on a graphite stopper, is constructed. The α-decay of the superheavy nuclides or spontaneous fission products will be detected with a silicon 192 strips detector. The experimental program of future investigations using the technique of a gas catcher is discussed. It should be regarded as an alternative of the classical ISOL technique. The possibilities are considered for using this mass-spectrometer for laser spectroscopy of nuclei far off-stability.

Formation of Neutron-Enriched Heavy and Superheavy Nuclei in Fusion Reactions

NASA Astrophysics Data System (ADS)

Karpov, A. V.; Rachkov, V. A.; Saiko, V. V.

2018-05-01

The formation of new isotopes of heavy and superheavy elements in the fusion of neutron-enriched projectiles with actinide targets is discussed. Cross sections for the formation of evaporation residues in fusion reactions is predicted for several combinations of colliding nuclei.

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

NASA Astrophysics Data System (ADS)

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.

What perspectives for the synthesis of heavier superheavy nuclei? Results and comparison with models

NASA Astrophysics Data System (ADS)

Mandaglio, G.; Nasirov, A. K.; Curciarello, F.; De Leo, V.; Romaniuk, M.; Fazio, G.; Giardina, G.

2013-03-01

The possibility to synthesize heavier superheavy elements in massive nuclei reactions is strongly limited by the hindrance to complete fusion of reacting nuclei: due to the onset of the quasifission process in the entrance channel, which competes with complete fusion, and by strong increase of the fission yield along the de-excitation cascade of the compound nucleus in comparison to the evaporation residue formation. We present a wide and detailed procedure allowing us to describe the experimental results (evaporation residue nuclei and fissionlike products) in the mass asymmetric and symmetric reactions. Very reliable estimations and perspectives for the synthesis of superheavy elements in many massive nuclei reactions up to Z = 120 and eventually also for Z > 120 have been obtained.

Cluster preformation law for heavy and superheavy nuclei

NASA Astrophysics Data System (ADS)

Wei, K.; Zhang, H. F.

2017-08-01

The concept of cluster radioactivity has been extended to allow emitted particles with ZC>28 for superheavy nuclei by nuclear theory [Poenaru et al., Phys. Rev. Lett. 107, 062503 (2011), 10.1103/PhysRevLett.107.062503]. The preformation and emission mechanics of heavy-ion particles must be examined again before the fascinating radioactivity is observed for superheavy nuclei in laboratory. We extract the cluster preformation factor for heavy and superheavy nuclei within a preformed cluster model, in which the decay constant is the product of the preformation factor, assault frequency, and penetration probability. The calculated results show that the cluster penetration probability for superheavy nuclei is larger than that for actinide elements. The preformation factor depends on the nuclear structures of the emitted cluster and mother nucleus, and the well-known cluster preformation law S (AC) =S (α) (AC-1 )/3 [Blendowske and Walliser, Phys. Rev. Lett. 61, 1930 (1988), 10.1103/PhysRevLett.61.1930] will break down when the mass number of the emitted cluster Ac>28 , and new preformation formulas are proposed to estimate the preformation factor for heavy and superheavy nuclei.

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

NASA Astrophysics Data System (ADS)

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.

On the way to unveiling the atomic structure of superheavy elements

NASA Astrophysics Data System (ADS)

Laatiaoui, Mustapha

2016-12-01

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.

Studying Nuclear Structure at the extremes with S3

NASA Astrophysics Data System (ADS)

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.

Peaceful berkelium

NASA Astrophysics Data System (ADS)

Trabesinger, Andreas

2017-09-01

The first new element produced after the Second World War has led a rather peaceful life since entering the period table -- until it became the target of those producing superheavy elements, as Andreas Trabesinger describes.

The production of transuranium elements by the r-process nucleosynthesis

NASA Astrophysics Data System (ADS)

Goriely, S.; Martínez Pinedo, G.

2015-12-01

The production of super-heavy transuranium elements by stellar nucleosynthesis processes remains an open question. The most promising process that could potentially give rise to the formation of such elements is the so-called rapid neutron-capture process, or r-process, known to be at the origin of approximately half of the A > 60 stable nuclei observed in nature. However, despite important efforts, the astrophysical site of the r-process remains unidentified. Here, we study the r-process nucleosynthesis in material that is dynamically ejected by tidal and pressure forces during the merging of binary neutron stars. Neutron star mergers could potentially be the dominant r-process site in the Galaxy, but also due to the extreme neutron richness found in such environment, could potentially synthesise super-heavy elements. R-process nucleosynthesis during the decompression is known to be largely insensitive to the detailed astrophysical conditions because of efficient fission recycling, producing a composition that closely follows the solar r-abundance distribution for nuclei with mass numbers A > 140. During the neutron irradiation, nuclei up to charge numbers Z ≃ 110 and mass number A ≃ 340 are produced, with a major peak production at the N = 184 shell closure, i.e. around A ≃ 280. Super-heavy nuclei with Z > 110 can hardly be produced due to the efficient fission taking place along those isotopic chains. Long-lived transuranium nuclei are inevitably produced by the r-process. The predictions concerning the production of transuranium nuclei remain however very sensitive to the predictions of fission barrier heights for such super-heavy nuclei. More nuclear predictions within different microscopic approaches are needed.

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

NASA Astrophysics Data System (ADS)

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

1999-05-01

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.

Dissipative dynamics in quasifission

NASA Astrophysics Data System (ADS)

Oberacker, V. E.; Umar, A. S.; Simenel, C.

2014-11-01

Quasifission is the primary reaction mechanism that prevents the formation of superheavy elements in heavy-ion fusion experiments. Employing the time-dependent density functional theory approach, we study quasifission in the systems Ca,4840+238U . Results show that for 48Ca projectiles the quasifission is substantially reduced in comparison to the 40Ca case. This partly explains the success of superheavy element formation with 48Ca beams. For the first time, we also calculate the repartition of excitation energies of the two fragments in a dynamic microscopic theory. The differences between both systems are interpreted in terms of initial neutron to proton asymmetry of the colliding partners.

A high-resolution study of ultra-heavy cosmic-ray nuclei (A0178)

NASA Technical Reports Server (NTRS)

Osullivan, D.; Thompson, A.; Oceallaigh, C.; Domingo, V.; Wenzel, K. P.

1984-01-01

The main objective of the experiment is a detailed study of the charge spectra of ultraheavy cosmic-ray nuclei from zinc (Z = 30) to uranium (Z = 92) and beyond using solid-state track detectors. Special emphasis will be placed on the relative abundances in the region Z or - 65, which is thought to be dominated by r-process nucleosynthesis. Subsidiary objectives include the study of the cosmic-ray transiron spectrum a search for the postulated long-lived superheavy (SH) nuclei (Z or = 110), such as (110) SH294, in the contemporary cosmic radiation. The motivation behind the search for super-heavy nuclei is based on predicted half-lives that are short compared to the age of the Earth but long compared to the age of cosmic rays. The detection of such nuclei would have far-reaching consequences for nuclear structure theory. The sample of ultraheavy nuclei obtained in this experiment will provide unique opportunities for many tests concerning element nucleosynthesis, cosmic-ray acceleration, and cosmic-ray propagation.

Theoretical prediction of probable isotopes of superheavy nuclei of Z = 122

NASA Astrophysics Data System (ADS)

Manjunatha, H. C.

2016-11-01

We have studied the α-decay half-life and spontaneous fission half-lives of isotopes of superheavy element Z = 122 in the range 275 ≤ A ≥ 326. A comparison of calculated alpha half-lives with the literature [D. N. Poenaru, R. A. Gherghescu and W. Greiner, Phys. Rev. C 83 (2011) 014601, D. N. Poenaru, R. A. Gherghescu and W. Greiner, Phys. Rev. C 85 (2012) 034615] and the analytical formulas of Royer [G. Royer, J. Phys. G; Nucl. Part. Phys. 26 (2000) 1149] shows good agreement with each other. To identify the mode of decay of these isotopes, the spontaneous-fission half-lives were also evaluated using the semiempirical relation given by [C. Xu, Z. Ren and Y. Guo, Phys. Rev. C 78 (2008) 044329]. A comparative study on the competition of alpha decay versus spontaneous fission of superheavy nuclei (SHN) reveals that around eight isotopes (307-314122) survive fission and have alpha decay channel as the prominent mode of decay and hold the possibility to be synthesized in the laboratory. The alpha decay half-lives and spontaneous fission half-lives of SHN with Z = 122, A = 299-306, with Z = 120, A = 294-300, and with Z = 119, A = 292-297 are also studied. The present study will be useful in the synthesis of superheavy elements Z > 118 by using the actinide based reactions with stable projectiles heavier than 48Ca.

The Superheavy Elements and Anti-Gravity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anastasovski, Petar K.

2004-02-04

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 thesemore » 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.« less

The Superheavy Elements and Anti-Gravity

NASA Astrophysics Data System (ADS)

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 < 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.

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

DOE PAGES

Hofmann, S.; Heinz, S.; Mann, R.; ...

2016-06-28

The reaction 54Cr$ + $248Cm 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.more » 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. Furthermore, 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.« less

ORNL actinide materials and a new detection system for superheavy nuclei

NASA Astrophysics Data System (ADS)

Rykaczewski, Krzysztof P.; Roberto, James B.; Brewer, Nathan T.; Utyonkov, Vladimir K.

2016-12-01

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.

Processes in massive nuclei reactions and the way to complete fusion of reactants. What perspectives for the synthesis of heavier superheavy elements?

NASA Astrophysics Data System (ADS)

Mandaglio, G.; Nasirov, A. K.; Curciarello, F.; De Leo, V.; Romaniuk, M.; Fazio, G.; Giardina, G.

2012-12-01

By using the dinuclear system (DNS) model we determine the capture of reactants at the first stage of reaction, the competition between the DNS decay by the quasifission (QF) and the complete fusion (CF) process up to formation of the compound nucleus (CN) having compact shape. Further evolution of the CN is considered as its fission into two fragments or formation of evaporation residues (ER) by its cooling after emission of neutrons or/and charged light particles. Disappearance of the CN fission barrier due to its fast rotation leads to the fast fission (FF) by formation of fissionlike fragments. The results of calculations for the mass symmetric 136Xe+136Xe reaction, almost mass symmetric 108Mo+144Ba reaction, and mass asymmetric like 24Mg+238U and 34S+248Cm reactions are discussed. The fusion probability PCN calculated for many massive nuclei reactions leading to formation of superheavy nuclei have been analyzed. The reactions which can lead in perspective to the synthesis of superheavy elements in the Z = 120 - 126 range and, eventually, also to heaviest nuclei, are discussed.

Prospects of heavy and superheavy element production via inelastic nucleus-nucleus collisions - from 238U+238U to18O+254Es

NASA Astrophysics Data System (ADS)

Schädel, Matthias

2016-12-01

Multi-nucleon transfer reactions, frequently termed deep-inelastic, between heavy-ion projectiles and actinide targets provide prospects to synthesize unknown isotopes of heavy actinides and superheavy elements with neutron numbers beyond present limits. The 238U on 238U reaction, which revealed essential aspects of those nuclear reactions leading to surviving heavy nuclides, mainly produced in 3n and 4n evaporation channels, is discussed in detail. Positions and widths of isotope distributions are compared. It is shown, as a general rule, that cross sections peak at irradiation energies about 10% above the Coulomb barrier. Heavy target nuclei are essential for maximizing cross sections. Experimental results from the 238U on 248Cm reaction, including empirical extrapolations, are compared with theoretical model calculations predicting relatively high cross sections for neutron-rich nuclei. Experiments to test the validity of such predictions are proposed. Comparisons between rather symmetric heavy-ion reactions like 238U on 248Cm (or heavier targets up to 254Es) with very asymmetric ones like 18O on 254Es reveal that the ones with 238U as a projectile have the highest potential in the superheavy element region while the latter ones can be advantageous for the synthesis of heavy actinide isotopes. Concepts for highly efficient recoil separators designed for transfer products are presented.

α-decay systematics for superheavy elements

NASA Astrophysics Data System (ADS)

Duarte, S. B.; Teruya, N.

2012-01-01

In this Brief Report we extend the α-decay half-life calculation to the superheavy emitter region to verify whether these nuclei satisfy the recently observed systematics [D. N. Poenaru , Phys. Rev. CPRVCAN0556-281310.1103/PhysRevC.83.014601 83, 014601 (2011);C. Qi , Phys. Rev. CPRVCAN0556-281310.1103/PhysRevC.80.044326 80, 044326 (2009)]. To establish the systematics, we have used the α-cluster potential description, which was originally developed to study α decay in connection with nuclear energy level structure [B. Buck , Phys. Rev. CPRVCAN0556-281310.1103/PhysRevC.51.559 51, 559 (1995)]. The quantum-mechanical tunneling calculation has been employed to obtain the half-lives, showing that with this treatment the systematics are well reproduced in the region of heavy nuclei. Finally, the half-life calculation has been extended to the superheavy emitters to verify whether the systematics can still be observed.

Element 117

ScienceCinema

None

2018-06-12

An international team of scientists from Russia and the United States, including two Department of Energy national laboratories and two universities, has discovered the newest superheavy element, element 117. The team included scientists from the Joint Institute of Nuclear Research (Dubna, Russia), the Research Institute for Advanced Reactors (Dimitrovgrad), Lawrence Livermore National Laboratory, Oak Ridge National Laboratory, Vanderbilt University, and the University of Nevada, Las Vegas.

Chemical studies of elements with Z ⩾ 104 in gas phase

NASA Astrophysics Data System (ADS)

Türler, Andreas; Eichler, Robert; Yakushev, Alexander

2015-12-01

Chemical investigations of superheavy elements in the gas-phase, i.e. elements with Z ≥ 104, allow assessing the influence of relativistic effects on their chemical properties. Furthermore, for some superheavy elements and their compounds quite unique gas-phase chemical properties were predicted. The experimental verification of these properties yields supporting evidence for a firm assignment of the atomic number. Prominent examples are the high volatility observed for HsO4 or the very weak interaction of Cn with gold surfaces. The unique properties of HsO4 were exploited to discover the doubly-magic even-even nucleus 270Hs and the new isotope 271Hs. The combination of kinematic pre-separation and gas-phase chemistry allowed gaining access to a new class of relatively fragile compounds, the carbonyl complexes of elements Sg through Mt. A not yet resolved issue concerns the interaction of Fl with gold surfaces. While competing experiments agree on the fact that Fl is a volatile element, there are discrepancies concerning its adsorption on gold surfaces with respect to its daughter Cn. The elucidation of these and other questions amounts to the fascination that gas-phase chemical investigations exert on current research at the extreme limits of chemistry today.

Systematic study of probable projectile-target combinations for the synthesis of the superheavy nucleus 302120

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Safoora, V.

2016-08-01

Probable projectile-target combinations for the synthesis of the superheavy element 302120 have been studied taking the Coulomb and proximity potential as the interaction barrier. The probabilities of the compound nucleus formation PCN for the projectile-target combinations found in the cold reaction valley of 302120 are estimated. At energies near and above the Coulomb barrier, we have calculated the capture, fusion, and evaporation residue cross sections for the reactions of all probable projectile-target combinations so as to predict the most promising projectile-target combinations for the synthesis of the superheavy element 302120 in heavy-ion fusion reactions. The calculated fusion and evaporation cross sections for the more asymmetric ("hotter") projectile-target combination is found to be higher than the less asymmetric ("colder") combination. It can be seen from the nature of the quasifission barrier height, mass asymmetry, the probability of compound nucleus formation, survival probability, and excitation energy, the systems 44Ar+258No , 46Ar+256No , 48Ca+254Fm , 50Ca+252Fm , 54Ti+248Cf , and 58Cr+244Cm in deep region I of the cold reaction valley and the systems 62Fe+240Pu , 64Fe+238Pu , 68Ni+234U , 70Ni+232U , 72Ni+230U , and 74Zn+228Th in the other cold valleys are identified as the better projectile-target combinations for the synthesis of 302120. Our predictions on the synthesis of 302120 superheavy nuclei using the combinations 54Cr+248Cm , 58Fe+244Pu , 64Ni+238U , and 50Ti+249Cf are compared with available experimental data and other theoretical predictions.

Basic distinctions between cold- and hot-fusion reactions in the synthesis of superheavy elements

NASA Astrophysics Data System (ADS)

Nasirov, A. K.; Muminov, A. I.; Giardina, G.; Mandaglio, G.

2014-07-01

Superheavy elements (SHE) of charge number in the range of Z = 106-112 were synthesized in so-called cold-fusion reactions. The smallness of the excitation energy of compound nuclei is the main advantage of cold-fusion reactions. However, the synthesis of SHEs of charge number in the region of Z ≥ 112 is strongly complicated in cold-fusion reactions by a sharp decrease in the cross section of a compound nucleus formation in the entrance channel because of superiority of quasifission in the competition with complete fusion. Two favorable circumstances contributed to the success of the experiments aimed at the synthesis of the Z = 113-118 elements and performed at the Laboratory of Nuclear Reactions at the Joint Institute for Nuclear Research: large cross sections for the production of a compound nucleus, which are characteristic of hot-fusion reactions, and an increase in the fission barrier for nuclei toward the stability island. The factor that complicates the formation of a compound nucleus in cold-fusion reactions is discussed.

Chemistry of the superheavy elements.

PubMed

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.

Chemistry Notes.

ERIC Educational Resources Information Center

School Science Review, 1982

1982-01-01

Presents background information, laboratory procedures, classroom materials/activities, and experiments for chemistry. Topics include superheavy elements, polarizing power and chemistry of alkali metals, particulate carbon from combustion, tips for the chemistry laboratory, interesting/colorful experiments, behavior of bismuth (III) iodine, and…

Superheavy-element spectroscopy: Correlations along element 115 decay chains

NASA Astrophysics Data System (ADS)

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.

Theoretical and experimental α decay half-lives of the heaviest odd-Z elements and general predictions

NASA Astrophysics Data System (ADS)

Zhang, H. F.; Royer, G.

2007-10-01

Theoretical α decay half-lives of the heaviest odd-Z nuclei are calculated using the experimental Qα value. The barriers in the quasimolecular shape path are determined within a Generalized Liquid Drop Model (GLDM) and the WKB approximation is used. The results are compared with calculations using the Density-Dependent M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulas. The calculations provide consistent estimates for the half-lives of the α decay chains of these superheavy elements. The experimental data stand between the GLDM calculations and VSS ones in the most time. Predictions are provided for the α decay half-lives of other superheavy nuclei within the GLDM and VSS approaches using the recent extrapolated Qα of Audi, Wapstra, and Thibault [Nucl. Phys. A729, 337 (2003)], which may be used for future experimental assignment and identification.

Exotic Archaeology:. Searching for Superheavy Elements in Nature and Dating Human DNA with the 14C Bomb Peak

NASA Astrophysics Data System (ADS)

Kutschera, Walter; Dellinger, Franz; Liebl, Jakob; Steier, Peter

2011-03-01

This contribution conveys the power of accelerator mass spectrometry (AMS) to measure ultra-low traces of long-lived radionuclides in two highly divers fields: Astrophysics and molecular biology. Our search for nuclides of superheavy elements (SHE) in several natural materials did not confirm the claims of positive evidence for SHEs reported by the group of Amnon Marinov from Jerusalem, even though the sensitivity of our AMS measurements were several orders of magnitude higher. We also report on the investigation by the group of Kirsty Spalding from Stockholm to date human DNA with the 14C bomb peak. This allows one to determine retrospectively the birth date of cells in sections of the human body. Ongoing efforts to miniaturize carbon samples down to the level of 10 μg C for AMS measurements will allow one to venture into ever smaller subsections of the human brain.

A review on SHE research at GANIL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stodel, Ch.; Anne, R.; Bouriquet, B.

This report summarizes the experiments relative to Super-Heavy Element studies done at GANIL - CEA - CNRS since 1999. It also gives an overview of future experiments and opportunities offered by SPIRAL 2 and LINAG beams in a medium term.

Analysis of spatial autocorrelation patterns of heavy and super-heavy rainfall in Iran

NASA Astrophysics Data System (ADS)

Rousta, Iman; Doostkamian, Mehdi; Haghighi, Esmaeil; Ghafarian Malamiri, Hamid Reza; Yarahmadi, Parvane

2017-09-01

Rainfall is a highly variable climatic element, and rainfall-related changes occur in spatial and temporal dimensions within a regional climate. The purpose of this study is to investigate the spatial autocorrelation changes of Iran's heavy and super-heavy rainfall over the past 40 years. For this purpose, the daily rainfall data of 664 meteorological stations between 1971 and 2011 are used. To analyze the changes in rainfall within a decade, geostatistical techniques like spatial autocorrelation analysis of hot spots, based on the Getis-Ord G i statistic, are employed. Furthermore, programming features in MATLAB, Surfer, and GIS are used. The results indicate that the Caspian coast, the northwest and west of the western foothills of the Zagros Mountains of Iran, the inner regions of Iran, and southern parts of Southeast and Northeast Iran, have the highest likelihood of heavy and super-heavy rainfall. The spatial pattern of heavy rainfall shows that, despite its oscillation in different periods, the maximum positive spatial autocorrelation pattern of heavy rainfall includes areas of the west, northwest and west coast of the Caspian Sea. On the other hand, a negative spatial autocorrelation pattern of heavy rainfall is observed in central Iran and parts of the east, particularly in Zabul. Finally, it is found that patterns of super-heavy rainfall are similar to those of heavy rainfall.

Superheavy nuclei from 48Ca-induced reactions

NASA Astrophysics Data System (ADS)

Oganessian, Yu. Ts.; Utyonkov, V. K.

2015-12-01

The discovery and investigation of the new region of superheavy nuclei at the DGFRS separator based on fusion reactions of 48Ca with 238U-249Cf target nuclei are reviewed. The production cross sections and summaries of the decay properties, including the results of the posterior experiments performed at the SHIP, BGS, and TASCA separators, as well as at the chemistry setups, are discussed and compared with the theoretical calculations and the systematic trends in the α-decay and spontaneous fission properties. The properties of the new nuclei, isotopes of elements 112-118, and their decay products demonstrate significant increases in the stability of the heaviest nuclei with increasing neutron number and closer approach to magic number N = 184.

Synthesis of Superheavy Nuclei in 48CA-INDUCED Reactions

NASA Astrophysics Data System (ADS)

Oganessian, Yu. Ts.; Utyonkov, V. K.; Lobanov, Yu. V.; Abdullin, F. Sh.; Polyakov, A. N.; Sagaidak, R. N.; Shirokovsky, I. V.; Tsyganov, Yu. S.; Voinov, A. A.; Gulbekian, G. G.; Bogomolov, S. L.; Gikal, B. N.; Mezentsev, A. N.; Iliev, S.; Subbotin, V. G.; Sukhov, A. M.; Subotic, K.; Zagrebaev, V. I.; Vostokin, G. K.; Itkis, M. G.; Moody, K. J.; Patin, J. B.; Shaughnessy, D. A.; Stoyer, M. A.; Stoyer, N. J.; Wilk, P. A.; Kenneally, J. M.; Landrum, J. H.; Wild, J. F.; Lougheed, R. W.

2008-11-01

Thirty-four new nuclides with Z = 104-116, 118 and N = 161-177 have been synthesized in the complete-fusion reactions of 238U, 237Np, 242,244Pu, 243Am, 245,248Cm, and 249Cf targets with 48Ca beams. The masses of evaporation residues were identified through measurements of the excitation functions of the xn-evaporation channels and from cross bombardments. The decay properties of the new nuclei agree with those of previously known heavy nuclei and with predictions from different theoretical models. A discussion of self-consistent interpretations of all observed decay chains originating from the parent isotopes 282,283112, 282113, 286-289114, 287,288115, 290-293116, and 294118 is presented. Decay energies and lifetimes of the neutron-rich superheavy nuclei as well as their production cross sections indicate a considerable increase in the stability of nuclei with an increasing number of neutrons, which agrees with the predictions of theoretical models concerning the decisive dependence of the structure and radioactive properties of superheavy elements on their proximity to the nuclear shells with N = 184 and Z = 114.

Improved version of a binding energy formula for heavy and superheavy nuclei with Z{>=}90 and N{>=}140

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong Tiekuang; Joint Center for Particle, Nuclear Physics and Cosmology, Nanjing 210008; Ren Zhongzhou

2008-06-15

A local formula of binding energy for heavy and superheavy nuclei has very recently been proposed [Dong and Ren, Phys. Rev. C 72, 064331 (2005)]. In this paper, the limit of the predictive ability of this local formula is investigated. It is found that the neutron-proton correlations should be considered when higher precision is required. On the one hand, we introduce a new term |N-Z-50|/A, and on the other hand we consider the different strengths of proton-proton, neutron-neutron, and neutron-proton pairing correlations. For the first time, the standard deviation {radical}({sigma}{sup 2}) of the binding energies for 117 nuclei with Z{>=}90more » and N{>=}140 is reduced to 0.105 MeV. The {alpha} decay energies Q{sub {alpha}} and half-lives T{sub {alpha}} of nuclei with Z=102-118 are reproduced quite well. The proton drip line of superheavy elements from Md (Z=101) to Ds (Z=110) are predicted.« less

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

NASA Astrophysics Data System (ADS)

Wittwer, D.; Abdullin, F. Sh.; Aksenov, N. V.; Albin, Yu. V.; Bozhikov, G. A.; Dmitriev, S. N.; Dressler, R.; Eichler, R.; Gäggeler, H. W.; Henderson, R. A.; Hübener, 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.; Sagaidak, R. N.; Serov, A.; Shirokovsky, I. V.; Shaughnessy, D. A.; Shishkin, S. V.; Sukhov, A. M.; Stoyer, M. A.; Stoyer, N. J.; Tereshatov, E. E.; Tsyganov, Yu. S.; Utyonkov, V. K.; Vostokin, G. K.; Wegrzecki, M.; Wilk, P. A.

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 244Pu( 48Ca; 3n) 289114. One decay chain assigned to an atom of 285112, the α-decay product of 289114, was observed.

Ultra-heavy cosmic rays: Theoretical implications of recent observations

NASA Technical Reports Server (NTRS)

Blake, J. B.; Hainebach, K. L.; Schramm, D. N.; Anglin, J. D.

1977-01-01

Extreme ultraheavy cosmic ray observations (Z greater or equal 70) are compared with r-process models. A detailed cosmic ray propagation calculation is used to transform the calculated source distributions to those observed at the earth. The r-process production abundances are calculated using different mass formulae and beta-rate formulae; an empirical estimate based on the observed solar system abundances is used also. There is the continued strong indication of an r-process dominance in the extreme ultra-heavy cosmic rays. However it is shown that the observed high actinide/Pt ratio in the cosmic rays cannot be fit with the same r-process calculation which also fits the solar system material. This result suggests that the cosmic rays probably undergo some preferential acceleration in addition to the apparent general enrichment in heavy (r-process) material. As estimate also is made of the expected relative abundance of superheavy elements in the cosmic rays if the anomalous heavy xenon in carbonaceous chondrites is due to a fissioning superheavy element.

Superheavy element chemistry at GARIS

NASA Astrophysics Data System (ADS)

Haba, Hiromitsu

2016-12-01

A gas-jet transport system has been installed to the RIKEN GAs-filled Recoil Ion Separator, GARIS to start up SuperHeavy Element (SHE) chemistry. This system is a promising approach for exploring new frontiers in SHE chemistry: background radioactivities from unwanted by-products are suppressed, a high gas-jet transport yield is achieved, and new chemical reactions can be investigated. Useful radioisotopes of 261Rfa,b, 262Db, and 265Sga,b for chemical studies were produced in the reactions of 248Cm(18O,5n)261Rfa,b, 248Cm(19F,5n)262Db, and 248Cm(22Ne,5n)265Sga,b, respectively. They were successfully extracted to a chemistry laboratory by the gas-jet method. Production and decay properties of 261Rfa,b, 262Db, and 265Sga,b were investigated in detail with the rotating wheel apparatus for α- and spontaneous fission spectrometry. Present status and perspectives of the SHE chemistry at GARIS are also briefly presented.

Alpha-decay chains of superheavy nuclei 292-296118

NASA Astrophysics Data System (ADS)

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.

Contribution of fission to heavy-element nucleosynthesis in an astrophysical r-process

NASA Astrophysics Data System (ADS)

Korneev, I. Yu.; Panov, I. V.

2011-12-01

During the formation of heavy elements in the neutron star merger (NSM) scenario with a fairly long duration of the r-process, most of the seed nuclei rapidly burn out at the initial stage. The nucleosynthesis wave rapidly reaches the region of actinoids, where beta-delayed, neutron-induced, and spontaneous fission are the main reaction channels. The fission products of transuranium elements are again drawn into the r-process as new seed nuclei to form the yields of elements with mass numbers A > 100. The contribution from the various types of fission to the formation of heavy and superheavy nuclei is investigated. The proposed r-process model applied to the NSM scenario describes well the observed abundances of chemical elements, which confirms the formation of the main r-process component in the NSM scenario. Simple extrapolations of the spontaneous fission half-lives are shown to be inapplicable for the region of nuclei with N ˜ 184, because the formulas do not reflect the increase in half-life when the shell structure changes as the number of neutrons approaches 184. The formation of superheavy elements in the r-process is possible, but their survival depends to a large extent on how reliable the predictions of nuclear parameters, including the half-lives of the forming nuclei from the island of long-lived isotopes, are. The contributions from various types of fission—neutron-induced, beta-delayed, and spontaneous one—to the formation of heavy elements in the main r-process have been determined.

The Super Separator Spectrometer S3 and the associated detection systems: SIRIUS & LEB-REGLIS3

NASA Astrophysics Data System (ADS)

Déchery, F.; Savajols, H.; Authier, M.; Drouart, A.; Nolen, J.; Ackermann, D.; Amthor, A. M.; Bastin, B.; Berryhill, A.; Boutin, D.; Caceres, L.; Coffey, M.; Delferrière, O.; Dorvaux, O.; Gall, B.; Hauschild, K.; Hue, A.; Jacquot, B.; Karkour, N.; Laune, B.; Le Blanc, F.; Lecesne, N.; Lopez-Martens, A.; Lutton, F.; Manikonda, S.; Meinke, R.; Olivier, G.; Payet, J.; Piot, J.; Pochon, O.; Prince, V.; Souli, M.; Stelzer, G.; Stodel, C.; Stodel, M.-H.; Sulignano, B.; Traykov, E.; Uriot, D.; S³, Sirius; Leb-Reglis3 Collaboration

2016-06-01

The Super Separator Spectrometer (S3) facility is developed in the framework of the SPIRAL2 project [1]. S3 has been designed to extend the capability of the facility to perform experiments with extremely low cross sections, taking advantage of the very high intensity stable beams of the superconducting linear accelerator of SPIRAL2. It will mainly use fusion-evaporation reactions to reach extreme regions of the nuclear chart: new opportunities will be opened for super-heavy element studies and spectroscopy at and beyond the driplines. In addition to our previous article (Déchery et al. [2]) introducing the optical layout of the spectrometer and the expected performances, this article will present the current status of the main elements of the facility: the target station, the superconducting multipole, and the magnetic and electric dipoles, with a special emphasis on the status of the detection system SIRIUS and on the low-energy branch which includes the REGLIS3 system. S3 will also be a source of low energy radioactive isotopes for delivery to the DESIR facility.

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

NASA Astrophysics Data System (ADS)

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.

New dimensions of the periodic system: superheavy, superneutronic, superstrange, antimatter nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greiner, Walter

2010-12-23

The possibilities for the extension of the periodic system into the islands of superheavy (SH) elements, to and beyond the neutron drip line and to the sectors of strangeness and antimatter are discussed. The multi-nucleon transfer processes in low-energy damped collisions of heavy actinide nuclei may help us to fill the gap between the nuclei produced in the ''hot'' fusion reactions and the continent of known nuclei. In these reactions we may also investigate the ''island of stability''. In many such collisions the lifetime of the composite giant system consisting of two touching nuclei turns out to be rather longmore » ({>=}10{sup -20} s); sufficient for observing line structure in spontaneous positron emission from super-strong electric fields (vacuum decay), a fundamental QED process not observed yet experimentally. At the neutron-rich sector near the drip line islands and extended ridges of quasistable nuclei are predicted by HF calculations. Such nuclei, as well as very long living superheavy nuclei may be provided in double atomic bomb explosions. A tremendously rich scenario of new nuclear structure emerges with new magic numbers in the strangeness domain. Various production mechanisms are discussed for these objects and for antinuclei in high energy heavy-ion collisions.« less

Radioactivity Registered With a Small Number of Events

NASA Astrophysics Data System (ADS)

Zlokazov, Victor; Utyonkov, Vladimir

2018-02-01

The synthesis of superheavy elements asks for the analysis of low statistics experimental data presumably obeying an unknown exponential distribution and to take the decision whether they originate from one source or have admixtures. Here we analyze predictions following from non-parametrical methods, employing only such fundamental sample properties as the sample mean, the median and the mode.

The generalized liquid drop model alpha-decay formula: Predictability analysis and superheavy element alpha half-lives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dasgupta-Schubert, N.; Reyes, M.A.

2007-11-15

The predictive accuracy of the generalized liquid drop model (GLDM) formula for alpha-decay half-lives has been investigated in a detailed manner and a variant of the formula with improved coefficients is proposed. The method employs the experimental alpha half-lives of the well-known alpha standards to obtain the coefficients of the analytical formula using the experimental Q{sub {alpha}} values (the DSR-E formula), as well as the finite range droplet model (FRDM) derived Q{sub {alpha}} values (the FRDM-FRDM formula). The predictive accuracy of these formulae was checked against the experimental alpha half-lives of an independent set of nuclei (TEST) that span approximatelymore » the same Z, A region as the standards and possess reliable alpha spectroscopic data, and were found to yield good results for the DSR-E formula but not for the FRDM-FRDM formula. The two formulae were used to obtain the alpha half-lives of superheavy elements (SHE) and heavy nuclides where the relative accuracy was found to be markedly improved for the FRDM-FRDM formula, which corroborates the appropriateness of the FRDM masses and the GLDM prescription for high Z, A nuclides. Further improvement resulted, especially for the FRDM-FRDM formula, after a simple linear optimization over the calculated and experimental half-lives of TEST was used to re-calculate the half-lives of the SHE and heavy nuclides. The advantage of this optimization was that it required no re-calculation of the coefficients of the basic DSR-E or FRDM-FRDM formulae. The half-lives for 324 medium-mass to superheavy alpha decaying nuclides, calculated using these formulae and the comparison with experimental half-lives, are presented.« less

REVIEWS OF TOPICAL PROBLEMS: Ultrahigh-energy neutrinos from astrophysical sources and superheavy particle decays

NASA Astrophysics Data System (ADS)

Ryabov, Vladimir A.

2006-09-01

Problems in the fields of neutrino astronomy and ultrahigh-energy astrophysics are reviewed. Neutrino fluxes produced in various astrophysical sources (bottom-up acceleration scenarios) and resulting from the decay of superheavy particles (top-down scenarios) are considered. Neutrino oscillation processes and the absorption and regeneration of neutrinos inside the earth are analyzed and some other factors affecting the intensity and flavor composition of astrophysical neutrino fluxes are discussed. Details of ultrahigh-energy neutrino interactions are discussed within the Standard Model, as well as using nonstandard scenarios predicting an anomalous increase in the inelastic neutrino-nucleon cross section. Ultrahigh-energy neutrino detection techniques currently in use in new-generation neutrino telescopes and cosmic ray detectors are also discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hofmann, S.; Heinz, S.; Mann, R.

The reaction 54Cr$ + $248Cm 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.more » 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. Furthermore, 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.« less

Pre-scission model predictions of fission fragment mass distributions for super-heavy elements

NASA Astrophysics Data System (ADS)

Carjan, N.; Ivanyuk, F. A.; Oganessian, Yu. Ts.

2017-12-01

The total deformation energy just before the moment of neck rupture for the heaviest nuclei for which spontaneous fission has been detected (Ds281279-, 281Rg and Cn284282-) is calculated. The Strutinsky's prescription is used and nuclear shapes just before scission are described in terms of Cassinian ovals defined for the fixed value of elongation parameter α = 0.98 and generalized by the inclusion of four additional shape parameters: α1, α3, α4, and α6. Supposing that the probability of each point in the deformation space is given by Boltzmann factor, the distribution of the fission-fragment masses is estimated. The octupole deformation α3 at scission is found to play a decisive role in determining the main feature of the mass distribution: symmetric or asymmetric. Only the inclusion of α3 leads to an asymmetric division. Finally, the calculations are extended to an unexplored region of super-heavy nuclei: the even-even Fl (Z = 114), Lv (Z = 116), Og (Z = 118) and (Z = 126) isotopes. For these nuclei, the most probable mass of the light fragment has an almost constant value (≈136) like in the case of the most probable mass of the heavy fragment in the actinide region. It is the neutron shell at 82 that makes this light fragment so stable. Naturally, for very neutron-deficient isotopes, the mass division becomes symmetric when N = 2 × 82.

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

NASA Astrophysics Data System (ADS)

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.

Analysis and application of heavy isotopes in the environment

NASA Astrophysics Data System (ADS)

Steier, Peter; Dellinger, Franz; Forstner, Oliver; Golser, Robin; Knie, Klaus; Kutschera, Walter; Priller, Alfred; Quinto, Francesca; Srncik, Michaela; Terrasi, Filippo; Vockenhuber, Christof; Wallner, Anton; Wallner, Gabriele; Wild, Eva Maria

2010-04-01

A growing number of AMS laboratories are pursuing applications of actinides. We discuss the basic requirements of the AMS technique of heavy (i.e., above ˜150 amu) isotopes, present the setup at the Vienna Environmental Research Accelerator (VERA) which is especially well suited for the isotope 236U, and give a comparison with other AMS facilities. Special emphasis will be put on elaborating the effective detection limits for environmental samples with respect to other mass spectrometric methods. At VERA, we have carried out measurements for radiation protection and environmental monitoring ( 236U, 239,240,241,242,244Pu), astrophysics ( 182Hf, 236U, 244Pu, 247Cm), nuclear physics, and a search for long-lived super-heavy elements ( Z > 100). We are pursuing the environmental distribution of 236U, as a basis for geological applications of natural 236U.

Electron and Nucleon Localization Functions of Oganesson: Approaching the Thomas-Fermi Limit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jerabek, Paul; Schuetrumpf, Bastian; Schwerdtfeger, Peter

Fermion localization functions are used to discuss electronic and nucleonic shell structure effects in the superheavy element oganesson, the heaviest element discovered to date. Spin-orbit splitting in the 7p electronic shell becomes so large (~10 eV) that Og is expected to show uniform-gas-like behavior in the valence region with a rather large dipole polarizability compared to the lighter rare gas elements. The nucleon localization in Og is also predicted to undergo a transition to the Thomas-Fermi gas behavior in the valence region. Finally, this effect, particularly strong for neutrons, is due to the high density of single-particle orbitals.

Electron and Nucleon Localization Functions of Oganesson: Approaching the Thomas-Fermi Limit

DOE PAGES

Jerabek, Paul; Schuetrumpf, Bastian; Schwerdtfeger, Peter; ...

2018-01-31

Fermion localization functions are used to discuss electronic and nucleonic shell structure effects in the superheavy element oganesson, the heaviest element discovered to date. Spin-orbit splitting in the 7p electronic shell becomes so large (~10 eV) that Og is expected to show uniform-gas-like behavior in the valence region with a rather large dipole polarizability compared to the lighter rare gas elements. The nucleon localization in Og is also predicted to undergo a transition to the Thomas-Fermi gas behavior in the valence region. Finally, this effect, particularly strong for neutrons, is due to the high density of single-particle orbitals.

Electron and Nucleon Localization Functions of Oganesson: Approaching the Thomas-Fermi Limit

NASA Astrophysics Data System (ADS)

Jerabek, Paul; Schuetrumpf, Bastian; Schwerdtfeger, Peter; Nazarewicz, Witold

2018-02-01

Fermion localization functions are used to discuss electronic and nucleonic shell structure effects in the superheavy element oganesson, the heaviest element discovered to date. Spin-orbit splitting in the 7 p electronic shell becomes so large (˜10 eV ) that Og is expected to show uniform-gas-like behavior in the valence region with a rather large dipole polarizability compared to the lighter rare gas elements. The nucleon localization in Og is also predicted to undergo a transition to the Thomas-Fermi gas behavior in the valence region. This effect, particularly strong for neutrons, is due to the high density of single-particle orbitals.

On the thermalization achieved in the reactions involving superheavy nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bansal, Rajni

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.

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

NASA Astrophysics Data System (ADS)

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.

Isotope shift, nonlinearity of King plots, and the search for new particles

NASA Astrophysics Data System (ADS)

Flambaum, V. V.; Geddes, A. J.; Viatkina, A. V.

2018-03-01

We derive a mean-field relativistic formula for the isotope shift of an electronic energy level for arbitrary angular momentum; we then use it to predict the spectra of superheavy metastable neutron-rich isotopes belonging to the hypothetical island of stability. Our results may be applied to the search for superheavy atoms in astrophysical spectra using the known values of the transition frequencies for the neutron-deficient isotopes produced in the laboratory. An example of a relevant astrophysical system may be the spectra of the Przybylski's star where superheavy elements up to Z =99 have been possibly identified. In addition, it has been recently suggested to use the measurements of King plot nonlinearity in a search for hypothetical new light bosons. On the other hand, one can find the nonlinear corrections to the King plot arising already in the standard model framework. We investigate contributions to the nonlinearity arising from relativistic effects in the isotope field shift, the nuclear polarizability, and many-body effects. It is found that the nuclear polarizability contribution can lead to the significant deviation of the King plot from linearity. Therefore, the measurements of the nonlinearity of King plots may be applied to obtain the nuclear polarizability change between individual isotopes. We then proceed with providing a rough analytical estimate of the nonlinearity arising solely from the effect of a hypothetical scalar boson. Our predictions give theoretical limitations on the sensitivity of the search for new interactions and should help to identify the most suitable atoms for corresponding experiments.

Capabilities of the LDEF-2 heavy nuclei collection

NASA Technical Reports Server (NTRS)

Drach, J.; Price, P. B.; Salamon, M. H.; Tarle, G.; Ahlen, S. P.

1985-01-01

To take the next big step beyond High Energy Astronomy Observatory (HEAO-3) the Heavy Nuclei Collector (HNC), to be carried on an LDEF reflight, has the goals of greatly increased collecting power ( 30 actinides) and charge resolution sigma sub Z or = 0.25 E for Z up to approximately 100, which will provide abundances of all the charges 40 or Z or = 96 and permit sensitive searches for hypothetical particles such as monopoles, superheavy elements, and quark nuggets.

alpha-decay half-lives and Q{sub a}lpha values of superheavy nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong Jianmin; Graduate University of Chinese Academy of Sciences, Beijing 100049; School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000

2010-06-15

The alpha-decay half-lives of recently synthesized superheavy nuclei (SHN) are investigated by employing a unified fission model (UFM) where a new method to calculate the assault frequency of alpha emission is used. The excellent agreement with the experimental data indicates the UFM is a useful tool to investigate these alpha decays. It is found that the alpha-decay half-lives become more and more insensitive to the Q{sub a}lpha values as the atomic number increases on the whole, which is favorable for us to predict the half-lives of SHN. In addition, a formula is proposed to compute the Q{sub a}lpha values formore » the nuclei with Z>=92 and N>=140 with a good accuracy, according to which the long-lived SHN should be neutron rich. Several weeks ago, two isotopes of a new element with atomic number Z=117 were synthesized and their alpha-decay chains have been observed. The Q{sub a}lpha formula is found to work well for these nuclei, confirming its predictive power. The experimental half-lives are well reproduced by employing the UFM with the experimental Q{sub a}lpha values. This fact that the experimental half-lives are compatible with experimental Q{sub a}lpha values supports the synthesis of a new element 117 and the experimental measurements to a certain extent.« less

Fission in the landscape of heaviest elements: Some recent examples

NASA Astrophysics Data System (ADS)

Khuyagbaatar, J.; Yakushev, A.; Düllmann, Ch. E.; Ackermann, D.; Andersson, L.-L.; Block, M.; Brand, H.; Even, J.; Forsberg, U.; 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.

2016-12-01

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, 10-19-1024 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 10-5-103 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 254-256Rf and 266Lr are presented and corresponding factors for retarding the fission process are discussed.

Verification of Texas superheavy load criteria for bridges.

DOT National Transportation Integrated Search

2011-11-01

This report evaluates TxDOT criteria for the superheavy loads that trigger bridge analyses to determine : whether the criteria adequately protects Texas bridges. Researchers used solid modeling calibrated with a : bridge test of a 3-span continuous s...

{gamma}-vibrational states in superheavy nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun Yang; Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000; Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, Indiana 46556

2008-04-15

Recent experimental advances have made it possible to study excited structure in superheavy nuclei. The observed states have often been interpreted as quasiparticle excitations. We show that in superheavy nuclei collective vibrations systematically appear as low-energy excitation modes. By using the microscopic Triaxial Projected Shell Model, we make a detailed prediction on {gamma}-vibrational states and their E2 transition probabilities to the ground state band in fermium and nobelium isotopes where active structure research is going on, and in {sup 270}Ds, the heaviest isotope where decay data have been obtained for the ground-state and for an isomeric state.

Nuclear tracks in lunar samples

NASA Technical Reports Server (NTRS)

Price, P. B.

1971-01-01

An attempt is made to relate the appearance of an etched tract to the atomic number and velocity of the ion that left it using 10 MeV/nucleon Kr beams and 6 MeV/nucleon Zn beams. It was found that the etching rate along a tract in minerals and glass is a monototonic function of ionization rate thus, making particle identification possible. Results show the following were present in lunar samples: superheavy elements, cosmic rays with z greater than 26, and solar flare particles in Surveyor glass.

Feasibility of observing the α decay chains from isotopes of SHN with Z = 128, Z = 126, Z = 124 and Z = 122

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Priyanka, B.; Nithya, C.

2016-11-01

Within the Coulomb and proximity potential model for deformed nuclei (CPPMDN), the alpha decay properties of 34 isotopes of the superheavy nuclei with Z = 128 within the range 306 ≤ A ≤ 339 have been studied, considering both the parent and daughter nuclei to be deformed. The manuscript also deals with the decay properties of the isotopes of Z = 126 (within 288 ≤ A ≤ 339), Z = 124 (within 284 ≤ A ≤ 339) and Z = 122 (within 280 ≤ A ≤ 339). The alpha decay half lives thus evaluated have been compared with the values evaluated using other theoretical models and it was seen that, our theoretical alpha decay half lives match well with these values. Through the present study, we have underlined and have established the fact that, among the 192 isotopes considered in the present study, only those isotopes 321-324,328-335128, 318-320,323-327126, 305-308,315-322124 and 298-307,311-314122 can be synthesised and detected through alpha decay in laboratory. As the alpha decay half lives of these superheavy isotopes lie within the experimental limits, we hope these predictions, on the decay modes of these unknown nuclei, to pave the way for the future experiments. The proton separation energy calculations on 306-339128, 288-336126, 284-339124 and 280-339122 superheavy nuclei have also been done and the study revealed the probable proton emitters among these nuclei.

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

DOT National Transportation Integrated Search

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...

Synthesis of neutron-rich superheavy nuclei with radioactive beams within the dinuclear system model

NASA Astrophysics Data System (ADS)

Wu, Zhi-Han; Zhu, Long; Li, Fan; Yu, Xiao-Bin; Su, Jun; Guo, Chen-Chen

2018-06-01

The production of neutron-rich superheavy nuclei with Z =105 -118 in neutron evaporation channels is investigated within the dinuclear system model. The different stable and radioactive beam-induced hot fusion reactions are studied systematically. The prospect for synthesizing neutron-rich superheavy nuclei using radioactive beams is evaluated quantitatively based on the beam intensities proposed by Argonne Tandem Linac Accelerator System [B. B. Back and C. L. Jiang, Argonne National Laboratory Report No. ANL-06/55, 2006 (unpublished)]. All possible combinations (with projectiles of Z =16 -22 and half-lives longer than 1 ms; with targets of half-lives longer than 30 days), which can be performed in available experimental equipment, for producing several unknown neutron-rich superheavy nuclei in neutron evaporation channels are investigated and the most promising reactions are predicted. It is found that the stable beams still show great advantages for producing most of superheavy nuclei. The calculated results are also compared with production cross sections in the p x n and α x n evaporation channels [Hong et al., Phys. Lett. B 764, 42 (2017), 10.1016/j.physletb.2016.11.002]. We find that the radioactive beam-induced reactions are comparable to the stable beam-induced reactions in charged particle evaporation channels. To obtain more experimental achievements, the beam intensities of modern radioactive beam facilities need to be further improved in the future.

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

PubMed

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.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malli, Gulzari L., E-mail: malli@sfu.ca

Our ab initio all-electron fully relativistic Dirac-Fock (DF) and nonrelativistic Hartree-Fock (NR) calculations for seaborgium isocarbonyl SgOC predict atomization energy (AE) of 13.04 and 11.05 eV, respectively. However, the corresponding DF and NR atomization energies for the seaborgium carbonyl SgCO are predicted as 12.75 and 12.45 eV, respectively. This is the first such result in Chemistry where an isocarbonyl (and especially for a system of superheavy element Sg) is predicted to be more stable at the DF level of theory than the corresponding carbonyl. The predicted energy for the formation of the carbonyl SgCO at the relativistic DF and NRmore » levels of theory is -54.90 and -50.95 kJ /mol, whereas the corresponding energy of formation of the isocarbonyl SgOC is -64.44 and -18.64 kJ/mol, respectively. Ours are the first results of relativistic effects for isomerization and atomization energies of the superheavy seaborgium isocarbonyl SgOC and its isomer SgCO.The formation of isocarbonyl SgOC, should be favored over the carbonyl isomer SgCO in the first step of the reaction Sg+CO →SgOC.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malli, Gulzari L.

Our ab initio all-electron fully relativistic Dirac-Fock (DF) and nonrelativistic Hartree-Fock (NR) calculations for seaborgium isocarbonyl SgOC predict atomization energy (AE) of 13.04 and 11.05 eV, respectively. However, the corresponding DF and NR atomization energies for the seaborgium carbonyl SgCO are predicted as 12.75 and 12.45 eV, respectively. This is the first such result in Chemistry where an isocarbonyl (and especially for a system of superheavy element Sg) is predicted to be more stable at the DF level of theory than the corresponding carbonyl. The predicted energy for the formation of the carbonyl SgCO at the relativistic DF and NRmore » levels of theory is -54.90 and -50.95 kJ /mol, whereas the corresponding energy of formation of the isocarbonyl SgOC is -64.44 and -18.64 kJ/mol, respectively. Ours are the first results of relativistic effects for isomerization and atomization energies of the superheavy seaborgium isocarbonyl SgOC and its isomer SgCO. Lastly, the formation of isocarbonyl SgOC, should be favored over the carbonyl isomer SgCO in the first step of the reaction Sg+CO →SgOC.« less

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

NASA Astrophysics Data System (ADS)

Rather, Asloob A.; Ikram, M.; Usmani, A. A.; Kumar, Bharat; Patra, S. K.

2016-12-01

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 318-322138 isotopes.

First experiment at TASCA towards X-ray fingerprinting of element 115 decay chains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forsberg, U.; Golubev, P.; Sarmiento, L. G.

2012-01-01

To identify the atomic number of superheavy nuclei produced in 48Ca-induced fusion-evaporation reactions, an experiment aiming at measuring characteristic X-rays is being prepared at GSI, Darmstadt, Germany. The gas-filled separator TASCA will be employed, sending the residues towards the multi-coincidence detector setup TASISpec. Two ionoptical modes relying on differing magnetic polarities of the quadrupole magnets can be used at TASCA. New simulations and experimental tests of transmission and background suppression for these two focusing modes into TASISpec are presented.

Experiments on the Synthesis of Superheavy Elements with 48CA Beams at the Separator Vassilissa

NASA Astrophysics Data System (ADS)

Oganessian, Yu. Ts.; Yeremin, A. V.; Belozerov, A. V.; Chelnokov, M. L.; Chepigin, V. I.; Gorshkov, V. A.; Kabachenko, A. P.; Korotkov, S. P.; Malyshev, O. N.; Popeko, A. G.; Roháč, J.; Sagaidak, R. N.; Hofmann, S.; Münzenberg, G.; Veselsky, M.; Saro, S.; Iwasa, N.; Morita, K.; Giardina, G.

2001-04-01

The study of the decay properties and formation cross sections of the isotopes of elements 110, 112 and 114 were performed at the FLNR JINR with the use of the high intensity 48Ca beams and an electrostatic separator VASSILISSA. 232Th, 238U and 242Pu targets were used in the experiments. At the beam energies corresponding to the calculated cross section maxima of the 3n evaporation channels the isotopes 277110, 283112 and 287114 were produced and identified. The cross section limits were obtained at excitation energies of the compound nucleus corresponding to the maxima of the 4n evaporation channels for the reactions with 232Th and 238U targets.

Nucleus Z=126 with magic neutron number N=184 may be related to the measured Maruhn-Greiner maximum at A/2=155 from compound nuclei at low energy nuclear reactions

NASA Astrophysics Data System (ADS)

Prelas, M. A.; Hora, H.; Miley, G. H.

2014-07-01

Evaluation of nuclear binding energies from theory close to available measurements of a very high number of superheavy elements (SHE) based on α-decay energies Qα, arrived at a closing shell with a significant neutron number 184. Within the option of several discussed magic numbers for protons of around 120, Bagge's numbers 126 and 184 fit well and are supported by the element generation measurements by low energy nuclear reactions (LENR) discovered in deuterium loaded host metals. These measurements were showing a Maruhn-Greiner maximum from fission of compound nuclei in an excited state with double magic numbers for mutual confirmation.

Shell Corrections Stabilizing Superheavy Nuclei and Semi-spheroidal Atomic Clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poenaru, Dorin N.

2008-01-24

The macroscopic-microscopic method is used to illustrate the shell effect stabilizing superheavy nuclei and to study the stability of semi-spheroidal clusters deposited on planar surfaces. The alpha decay of superheavy nuclei is calculated using three models: the analytical superasymmetric fission model; the universal curve, and the semiempirical formula taking into account the shell effects. Analytical relationships are obtained for the energy levels of the new semi-spheroidal harmonic oscillator (SSHO) single-particle model and for the surface and curvature energies of the semi-spheroidal clusters. The maximum degeneracy of the SSHO is reached at a super-deformed prolate shape for which the minimum ofmore » the liquid drop model energy is also attained.« less

The generator coordinate Dirac-Fock method for open-shell atomic systems

NASA Astrophysics Data System (ADS)

Malli, Gulzari L.; Ishikawa, Yasuyuki

1998-11-01

Recently we developed generator coordinate Dirac-Fock and Dirac-Fock-Breit methods for closed-shell systems assuming finite nucleus and have reported Dirac-Fock and Dirac-Fock-Breit energies for the atoms He through Nobelium (Z=102) [see Refs. Reference 10Reference 11Reference 12Reference 13]. In this paper, we generalize our earlier work on closed-shell systems and develop a generator coordinate Dirac-Fock method for open-shell systems. We present results for a number of representative open-shell heavy atoms (with nuclear charge Z>80) including the actinide and superheavy transactinide (with Z>103) atomic systems: Fr (Z=87), Ac (Z=89), and Lr (Z=103) to E113 (eka-thallium, Z=113). The high accuracy obtained in our open-shell Dirac-Fock calculations is similar to that of our closed-shell calculations, and we attribute it to the fact that the representation of the relativistic dynamics of an electron in a spherical ball finite nucleus near the origin in terms of our universal Gaussian basis set is as accurate as that provided by the numerical finite difference method. The DF SCF energies calculated by Desclaux [At. Data. Nucl. Data Tables 12, 311 (1973)] (apart from a typographic error for Fr pointed out here) are higher than those reported here for atoms of some of the superheavy transactinide elements by as much as 5 hartrees (136 eV). We believe that this is due to the use by Desclaux of much larger atomic masses than the currently accepted values for these elements.

Double Higgs mechanisms, supermassive stable particles and the vacuum energy

NASA Astrophysics Data System (ADS)

Santillán, Osvaldo P.; Gabbanelli, Luciano

2016-07-01

In the present work, a hidden scenario which cast a long-lived superheavy particle A0 and simultaneously an extremely light particle a with mass ma ˜ 10-32-10-33 eV is presented. The potential energy V (a) of the particle a models the vacuum energy density of the universe ρc ≃ 10-47GeV4. On the other hand, the A0 particle may act as superheavy dark matter at present times and the products of its decay may be observed in high energy cosmic ray events. The hidden sector proposed here include light fermions with masses near the neutrino mass mν ˜ 10-2 eV and superheavy ones with masses of the order of the GUT scale, interacting through a hidden SU(2)L interaction which also affects the ordinary sector. The construction of such combined scenario is nontrivial since the presence of light particles may spoil the stability of the heavy particle A0. However, double Higgs mechanisms may be helpful for overcoming this problem. In this context, the stability of the superheavy particle A0 is ensured due to chiral symmetry arguments elaborated in the text.

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

NASA Astrophysics Data System (ADS)

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.

Decay properties of 256-339Ds superheavy nuclei

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Nithya, C.

2017-09-01

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_{10}T_{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 256-339Ds using various theoretical models will be helpful in the experimental identification of the isotopes of the element in the future.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexeev, Victor; Kalinina, Galina; Pavlova, Tatyana, E-mail: aval37@mail.ru, E-mail: gakalin@mail.ru, E-mail: pavlova4tat@mail.ru

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 ofmore » 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.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rampino, Sergio, E-mail: srampino@thch.unipg.it; Belpassi, Leonardo, E-mail: leonardo.belpassi@cnr.it; Storchi, Loriano

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 gasmore » 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.« less

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

PubMed

Rampino, Sergio; Storchi, Loriano; Belpassi, Leonardo

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), Au7- and Au20-E (E = Hg, Cn, Pb, Fl, Rn) complexes, where Au7 (planar) and Au20 (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 Au20-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.

Octupole deformation in neutron-rich actinides and superheavy nuclei and the role of nodal structure of single-particle wavefunctions in extremely deformed structures of light nuclei

NASA Astrophysics Data System (ADS)

Afanasjev, A. V.; Abusara, H.; Agbemava, S. E.

2018-03-01

Octupole deformed shapes in neutron-rich actinides and superheavy nuclei as well as extremely deformed shapes of the N∼ Z light nuclei have been investigated within the framework of covariant density functional theory. We confirmed the presence of new region of octupole deformation in neutron-rich actinides with the center around Z∼ 96,N∼ 196 but our calculations do not predict octupole deformation in the ground states of superheavy Z≥slant 108 nuclei. As exemplified by the study of 36Ar, the nodal structure of the wavefunction of occupied single-particle orbitals in extremely deformed structures allows to understand the formation of the α-clusters in very light nuclei, the suppression of the α-clusterization with the increase of mass number, the formation of ellipsoidal mean-field type structures and nuclear molecules.

Fission properties of superheavy nuclei for r -process calculations

NASA Astrophysics Data System (ADS)

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.

Final technical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loveland, Walter David

2016-08-27

This report describes the research carried out under this grant for the period from 1997 to 2014. This work has been previously described in annual progress reports and renewal applications. As a result of this project, ~100 papers were published in open refereed journals and 107 invited talks were given by the PI. The research subjects covered by this project included the synthesis and characterization of super-heavy nuclei, the critical study of the reaction mechanisms used in these synthesis reactions, the mechanism(s) of intermediate energy and relativistic nuclear collisions, the study of reactions induced by radioactive nuclear beams, and generalmore » properties of the heaviest elements.« less

Effects of relativity for atomization and isomerization energies of seaborgium carbonyl SgCO and seaborgium isocarbonyl SgOC: Relativity predicts SgOC to be more stable than SgCO

DOE PAGES

Malli, Gulzari L.

2015-12-31

Our ab initio all-electron fully relativistic Dirac-Fock (DF) and nonrelativistic Hartree-Fock (NR) calculations for seaborgium isocarbonyl SgOC predict atomization energy (AE) of 13.04 and 11.05 eV, respectively. However, the corresponding DF and NR atomization energies for the seaborgium carbonyl SgCO are predicted as 12.75 and 12.45 eV, respectively. This is the first such result in Chemistry where an isocarbonyl (and especially for a system of superheavy element Sg) is predicted to be more stable at the DF level of theory than the corresponding carbonyl. The predicted energy for the formation of the carbonyl SgCO at the relativistic DF and NRmore » levels of theory is -54.90 and -50.95 kJ /mol, whereas the corresponding energy of formation of the isocarbonyl SgOC is -64.44 and -18.64 kJ/mol, respectively. Ours are the first results of relativistic effects for isomerization and atomization energies of the superheavy seaborgium isocarbonyl SgOC and its isomer SgCO. Lastly, the formation of isocarbonyl SgOC, should be favored over the carbonyl isomer SgCO in the first step of the reaction Sg+CO →SgOC.« less

Recent progress in the studies of neutron-rich and high-$Z$ systems within the covariant density functional theory

DOE PAGES

Afanasjev, Anatoli V.; Agbemava, S. E.; Ray, D.; ...

2017-01-01

Here, the analysis of statistical and systematic uncertainties and their propagation to nuclear extremes has been performed. Two extremes of nuclear landscape (neutron-rich nuclei and superheavy nuclei) have been investigated. For the first extreme, we focus on the ground state properties. For the second extreme, we pay a particular attention to theoretical uncertainties in the description of fission barriers of superheavy nuclei and their evolution on going to neutron-rich nuclei.

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

NASA Astrophysics Data System (ADS)

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.

Measurement of the first ionization potential of astatine by laser ionization spectroscopy

PubMed Central

Rothe, S.; Andreyev, A. N.; Antalic, S.; Borschevsky, A.; Capponi, L.; Cocolios, T. E.; De Witte, H.; Eliav, E.; Fedorov, D. V.; Fedosseev, V. N.; Fink, D. A.; Fritzsche, S.; Ghys, L.; Huyse, M.; Imai, N.; Kaldor, U.; Kudryavtsev, Yuri; Köster, U.; Lane, J. F. W.; Lassen, J.; Liberati, V.; Lynch, K. M.; Marsh, B. A.; Nishio, K.; Pauwels, D.; Pershina, V.; Popescu, L.; Procter, T. J.; Radulov, D.; Raeder, S.; Rajabali, M. M.; Rapisarda, E.; Rossel, R. E.; Sandhu, K.; Seliverstov, M. D.; Sjödin, A. M.; Van den Bergh, P.; Van Duppen, P.; Venhart, M.; Wakabayashi, Y.; Wendt, K. D. A.

2013-01-01

The radioactive element astatine exists only in trace amounts in nature. Its properties can therefore only be explored by study of the minute quantities of artificially produced isotopes or by performing theoretical calculations. One of the most important properties influencing the chemical behaviour is the energy required to remove one electron from the valence shell, referred to as the ionization potential. Here we use laser spectroscopy to probe the optical spectrum of astatine near the ionization threshold. The observed series of Rydberg states enabled the first determination of the ionization potential of the astatine atom, 9.31751(8) eV. New ab initio calculations are performed to support the experimental result. The measured value serves as a benchmark for quantum chemistry calculations of the properties of astatine as well as for the theoretical prediction of the ionization potential of superheavy element 117, the heaviest homologue of astatine. PMID:23673620

Status of the project TRAPSENSOR: Performance of the laser-desorption ion source

NASA Astrophysics Data System (ADS)

Cornejo, J. M.; Lorenzo, A.; Renisch, D.; Block, M.; Düllmann, Ch. E.; Rodríguez, D.

2013-12-01

Penning traps provide mass measurements on atomic nuclei with the highest accuracy and sensitivity. Depending on the experiment and on the physics goal, a relative mass uncertainty varying from 10-7 to below 10-11 is required. Regarding sensitivity, the use of only one ion for the measurement is crucial, either to perform mass measurements on superheavy elements (SHE), or to reach δm/m≈10-11 in order to contribute to the direct determination of the mass of the electron-antineutrino with accurate mass measurements on specific nuclei. This has motivated the development of a new technique called Quantum Sensor based on a laser-cooled ion stored in a Penning trap, to perform mass measurements using fluorescence photons instead of electronic detection. The device is currently under development at the University of Granada (Spain) within the project TRAPSENSOR. We describe the physics which motivates the construction of this device, the expected performance of the Quantum Sensor compared to that from existing techniques, and briefly present the main components of the project. As a specific aspect of the project, the performance of the laser-desorption ion source utilized to produce calcium, rhenium and osmium ions at different kinetic energies is presented.

Mean-field studies of time reversal breaking states in super-heavy nuclei with the Gogny force

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robledo, L. M., E-mail: luis.robledo@uam.es

2015-10-15

Recent progress on the description of time reversal breaking (odd mass and multi-quasiparticle excitation) states in super-heavy nuclei within a mean field framework and using several flavors of the Gogny interaction is reported. The study includes ground and excited states in selected odd mass isotopes of nobelium and mendelevium as well as high K isomeric states in {sup 254}No. These are two and four-quasiparticle excitations that are treated in the same self-consistent HFB plus blocking framework as the odd mass states.

The effect of relativity on stability of Copernicium phases, their electronic structure and mechanical properties

NASA Astrophysics Data System (ADS)

Čenčariková, Hana; Legut, Dominik

2018-05-01

The phase stability of the various crystalline structures of the super-heavy element Copernicium was determined based on the first-principles calculations with different levels of the relativistic effects. We utilized the Darwin term, mass-velocity, and spin-orbit interaction with the single electron framework of the density functional theory while treating the exchange and correlation effects using local density approximations. It is found that the spin-orbit coupling is the key component to stabilize the body-centered cubic (bcc) structure over the hexagonal closed packed (hcp) structure, which is in accord with Sol. Stat. Comm. 152 (2012) 530, but in contrast to Atta-Fynn and Ray (2015) [11], Gaston et al. (2007) [10], Papaconstantopoulos (2015) [9]. It seems that the main role here is the correct description of the semi-core relativistic 6p1/2 orbitals. The all other investigated structures, i.e. face-centered cubic (fcc) , simple cubic (sc) as well as rhombohedral (rh) structures are higher in energy. The criteria of mechanical stability were investigated based on the calculated elastic constants, identifying the phase instability of fcc and rh structures, but surprisingly confirm the stability of the energetically higher sc structure. In addition, the pressure-induced structural transition between two stable sc and bcc phases has been detected. The ground-state bcc structure exhibits the highest elastic anisotropy from single elements of the Periodic table. At last, we support the experimental findings that Copernicium is a metal.

Influence of nuclear basic data on the calculation of production cross sections of superheavy nuclei

NASA Astrophysics Data System (ADS)

Bao, X. J.; Gao, Y.; Li, J. Q.; Zhang, H. F.

2015-07-01

The center of the predicted island of stability of superheavy nuclei (SHN) has not yet been observed experimentally. Many theories are being developed to understand the synthesizing mechanism of superheavy nuclei. However, all of them have to use some basic nuclear data. Three data tables, FRDM1995 [P. Möller et al., At. Data Nucl. Data Tables 59, 185 (1995), 10.1006/adnd.1995.1002], KTUY2005 [H. Koura et al., Prog. Theor. Phys. 113, 305 (2005), 10.1143/PTP.113.305], and WS2010 [Ning Wang et al., Phys. Rev. C 82, 044304 (2010), 10.1103/PhysRevC.82.044304], are used to investigate the SHN production. Based on the dinuclear system concept, the evaporation residue cross sections of SHN for Z =112-118 are calculated for the 48Ca -induced hot fusion reactions. It turns out that unlike the predictions made with the KTUY2005 and WS2010 data, the magic numbers Z =114 and N =184 predicted with the FRDM1995 data do not contradict the experimental data obtained so far.

Study of SHE at SHIP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hofmanna, Sigurd; Institut fuer Kernphysik, Goethe-Universitaet Frankfurt, Max von Laue-Strasse 1, 60438 Frankfurt am Main

2010-06-01

The nuclear shell model predicts that the next doubly magic shell-closure beyond {sup 208}Pb is at a proton number Z = 114, 120, or 126 and at a neutron number N = 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. Reactions used at SHIP are based on targets of lead and uranium. The decay data reveal that for the heaviest elements, the dominant decay mode is alpha emission, not fission. Decaymore » properties as well as reaction cross-sections are compared with results obtained at other laboratories and 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, detailed exploration of the region of spherical SHEs will start, after first steps on the island of SHEs were made in recent years.« less

Studies of SHE at SHIP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hofmann, Sigurd; Institut fuer Kernphysik, Goethe-Universitaet Frankfurt, Max von Laue-Strasse 1, 60438 Frankfurt am Main

2010-04-30

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

The chemistry of the superheavy elements. II. The stability of high oxidation states in group 11 elements: Relativistic coupled cluster calculations for the di-, tetra- and hexafluoro metallates of Cu, Ag, Au, and element 111

NASA Astrophysics Data System (ADS)

Seth, Michael; Cooke, Fiona; Schwerdtfeger, Peter; Heully, Jean-Louis; Pelissier, Michel

1998-09-01

The stability of the high oxidation states +3 and +5 in Group 11 fluorides is studied by relativistic Møller-Plesset (MP) and coupled cluster methods. Higher metal oxidation states are stabilized by relativistic effects. As a result, the hexafluoro complex of the Group 11 element with nuclear charge 111 and oxidation state +5 is the most stable compared to the other congeners. The results also suggest that AgF6- is thermodynamically stable and, therefore, it might be feasable to synthesize this compound. For the copper fluorides we observe very large oscillations in the Møller-Plesset series up to the fourth order. Nonrelativistic calculations lead to the expected trend in the metal-fluorine bond distances for the MF2- compounds, CuF2-

Superheavy magnetic monopoles and the standard cosmology

NASA Astrophysics Data System (ADS)

Turner, M. S.

1984-10-01

The superheavy magnetic monopoles predicted to exist in grand unified theories (GUTs) are for particle physics, astrophysics and cosmology. Astrophysical and cosmological considerations are invaluable in the study of the properties of GUT monopoles. Because of the glut of monopoles predicted in the standard cosmology for the simplest GUTs. The simplest GUTs and the standard cosmology are not compatible. This is a very important piece of information about physics at unification energies and about the earliest movements of the Universe. The cosmological consequences of GUT monopoles within the context of the standard hot big bang model are reviewed.

Uncertainty quantification and propagation in nuclear density functional theory

DOE PAGES

Schunck, N.; McDonnell, J. D.; Higdon, D.; ...

2015-12-23

Nuclear density functional theory (DFT) is one of the main theoretical tools used to study the properties of heavy and superheavy elements, or to describe the structure of nuclei far from stability. While on-going eff orts seek to better root nuclear DFT in the theory of nuclear forces, energy functionals remain semi-phenomenological constructions that depend on a set of parameters adjusted to experimental data in fi nite nuclei. In this study, we review recent eff orts to quantify the related uncertainties, and propagate them to model predictions. In particular, we cover the topics of parameter estimation for inverse problems, statisticalmore » analysis of model uncertainties and Bayesian inference methods. Illustrative examples are taken from the literature.« less

Nuclear mass formula with the shell energies obtained by a new method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koura, H.; Tachibana, T.; Yamada, M.

1998-12-21

Nuclear shapes and masses are estimated by a new method. The main feature of this method lies in estimating shell energies of deformed nuclei from spherical shell energies by mixing them with appropriate weights. The spherical shell energies are calculated from single-particle potentials, and, till now, two mass formulas have been constructed from two different sets of potential parameters. The standard deviation of the calculated masses from all the experimental masses of the 1995 Mass Evaluation is about 760 keV. Contrary to the mass formula by Tachibana, Uno, Yamada and Yamada in the 1987-1988 Atomic Mass Predictions, the present formulasmore » can give nuclear shapes and predict on super-heavy elements.« less

Mass and angular distributions of the reaction products in heavy ion collisions

NASA Astrophysics Data System (ADS)

Nasirov, A. K.; Giardina, G.; Mandaglio, G.; Kayumov, B. M.; Tashkhodjaev, R. B.

2018-05-01

The optimal reactions and beam energies leading to synthesize superheavy elements is searched by studying mass and angular distributions of fission-like products in heavy-ion collisions since the evaporation residue cross section consists an ignorable small part of the fusion cross section. The intensity of the yield of fission-like products allows us to estimate the probability of the complete fusion of the interacting nuclei. The overlap of the mass and angular distributions of the fusion-fission and quasifission products causes difficulty at estimation of the correct value of the probability of the compound nucleus formation. A study of the mass and angular distributions of the reaction products is suitable key to understand the interaction mechanism of heavy ion collisions.

Theoretical and experimental {alpha} decay half-lives of the heaviest odd-Z elements and general predictions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, H. F.; Royer, G.

Theoretical {alpha} decay half-lives of the heaviest odd-Z nuclei are calculated using the experimental Q{sub {alpha}} value. The barriers in the quasimolecular shape path are determined within a Generalized Liquid Drop Model (GLDM) and the WKB approximation is used. The results are compared with calculations using the Density-Dependent M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulas. The calculations provide consistent estimates for the half-lives of the {alpha} decay chains of these superheavy elements. The experimental data stand between the GLDM calculations and VSS ones in the most time. Predictions are provided for the {alpha} decay half-lives of other superheavymore » nuclei within the GLDM and VSS approaches using the recent extrapolated Q{sub {alpha}} of Audi, Wapstra, and Thibault [Nucl. Phys. A729, 337 (2003)], which may be used for future experimental assignment and identification.« less

Recent α decay half-lives and analytic expression predictions including superheavy nuclei

NASA Astrophysics Data System (ADS)

Royer, G.; Zhang, H. F.

2008-03-01

New recent experimental α decay half-lives have been compared with the results obtained from previously proposed formulas depending only on the mass and charge numbers of the α emitter and the Qα value. For the heaviest nuclei they are also compared with calculations using the Density-Dependent M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulas. The correct agreement allows us to make predictions for the α decay half-lives of other still unknown superheavy nuclei from these analytic formulas using the extrapolated Qα of G. Audi, A. H. Wapstra, and C. Thibault [Nucl. Phys. A729, 337 (2003)].

Central depression in nuclear density and its consequences for the shell structure of superheavy nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Afanasjev, A.V.; Laboratory of Radiation Physics, Institute of Solid State Physics, University of Latvia, LV 2169 Salaspils, Miera str. 31; Frauendorf, S.

The influence of the central depression in the density distribution of spherical superheavy nuclei on the shell structure is studied within the relativistic mean-field theory. A large depression leads to the shell gaps at the proton Z=120 and neutron N=172 numbers, whereas a flatter density distribution favors N=184 and leads to the appearance of a Z=126 shell gap and to the decrease of the size of the Z=120 shell gap. The correlations between the magic shell gaps and the magnitude of the central depression are discussed for relativistic and nonrelativistic mean field theories.

Recoil- α -fission and recoil- α – α -fission events observed in the reaction 48 Ca + 243 Am

DOE PAGES

Forsberg, U.; Rudolph, D.; Andersson, L. -L.; ...

2016-04-26

A recent high-resolution α, X-ray, and γ-ray coincidence-spectroscopy experiment at GSI offered the first glimpse of excitation schemes of isotopes along α-decay chains of Z=115. To understand these observations and to make predictions about shell structure of superheavy nuclei below 288115, we employed nuclear DFT. We find that the presence and nature of low-energy E1 transitions in well-deformed nuclei around Z=110, N=168 strongly depends on the strength of the spin-orbit coupling; hence, it provides an excellent constraint on theoretical models of superheavy nuclei.

Investigation on the quasifission process by theoretical analysis of experimental data of fissionlike reaction products

NASA Astrophysics Data System (ADS)

Giardina, G.; Nasirov, A. K.; Mandaglio, G.; Curciarello, F.; De Leo, V.; Fazio, G.; Manganaro, M.; Romaniuk, M.; Saccá, C.

2011-02-01

The hindrance to complete fusion is a phenomenon presenting in the most part of the capture events in reactions with massive nuclei. This phenomenon is due to the onset of the quasifission process which competes with complete fusion during the evolution of the composed system formed at capture stage. The branching ratio between quasifission and complete fusion strongly depends from different characteristics of reacting nuclei in the entrance channel. The experimental and theoretical investigations of reaction dynamics connected with the formation of composed system is nowadays the main subject of the nuclear reactions. There is ambiguity in establishment of the reaction mechanism leading to the observed binary fissionlike fragments. The correct estimation of the fusion probability is important in planning experiments for the synthesis of superheavy elements. The experimental determination of evaporation residues only is not enough to restore the true reaction dynamics. The experimental observation of fissionlike fragments only cannot assure the correct distinguishing of products of the quasifission, fast fission, and fusion-fission processes which have overlapping in the mass (angular, kinetic energy) distributions of fragments. In this paper we consider a wide set of reactions (with different mass asymmetry and mass symmetry parameters) with the aim to explain the role played by many quantities on the reaction mechanisms. We also present the results of study of the 48Ca+249Bk reaction used to synthesize superheavy nuclei with Z = 117 by the determination of the evaporation residue cross sections and the effective fission barriers < Bf > of excited nuclei formed along the de-excitation cascade of the compound nucleus.

α -decay chains of the superheavy nuclei Rg-350255

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Nithya, C.

2017-05-01

The decay modes and half-lives of 96 isotopes of the superheavy element roentgenium (Rg) within the range of 255 ≤A ≤350 come under investigation in the present paper. The isotopes which lie beyond the proton drip line are identified by calculating the one-proton and two-proton separation energies. The α -decay half-lives are calculated using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). For a theoretical comparison the α half-lives are also evaluated using the Viola-Seaborg semiempirical relation, the universal curve of Poenaru et al., the analytical formula of Royer, and the universal decay law of Qi et al. Spontaneous fission half-lives are computed with the shell-effect-dependent formula of Santhosh and Nithya and the semiempirical formula of Xu et al. The decay modes are predicted by comparing the α -decay half-lives within the CPPMDN with the corresponding spontaneous fission half-lives computed by the shell-effect-dependent formula of Santhosh and Nithya. In our paper it is seen that the isotopes 255-271,273Rg lie beyond the proton drip line and hence decay through proton emission. The isotopes 272,274-277Rg exhibit long α chains. Three α chains are predicted from the isotopes Rg-282278. The isotopes Rg-345283 decay through spontaneous fission. The isotopes Rg-350346 are found to be stable against α decay. The theoretical results are compared with the available experimental results and are seen to be matching well. We hope that our predictions will be useful in future experimental investigations.

Lead and uranium group abundances in cosmic rays

NASA Technical Reports Server (NTRS)

Yadav, J. S.; Perelygin, V. P.

1985-01-01

The importance of Lead and Uranium group abundances in cosmic rays is discussed in understanding their evolution and propagation. The electronic detectors can provide good charge resolution but poor data statistics. The plastic detectors can provide somewhat better statistics but charge resolution deteriorates. The extraterrestrial crystals can provide good statistics but with poor charge resolution. Recent studies of extraterrestrial crystals regarding their calibration to accelerated uranium ion beam and track etch kinetics are discussed. It is hoped that a charge resolution of two charge units can be achieved provided an additional parameter is taken into account. The prospects to study abundances of Lead group, Uranium group and superheavy element in extraterrestrial crystals are discussed, and usefulness of these studies in the light of studies with electronic and plastic detectors is assessed.

Fusion cross sections for reactions involving medium and heavy nucleus-nucleus systems

NASA Astrophysics Data System (ADS)

Atta, Debasis; Basu, D. N.

2014-12-01

Existing data on near-barrier fusion excitation functions of medium and heavy nucleus-nucleus systems have been analyzed by using a simple diffused-barrier formula derived assuming the Gaussian shape of the barrier-height distributions. The fusion cross section is obtained by folding the Gaussian barrier distribution with the classical expression for the fusion cross section for a fixed barrier. The energy dependence of the fusion cross section, thus obtained, provides good description to the existing data on near-barrier fusion and capture excitation functions for medium and heavy nucleus-nucleus systems. The theoretical values for the parameters of the barrier distribution are estimated which can be used for fusion or capture cross-section predictions that are especially important for planning experiments for synthesizing new superheavy elements.

Formation of superheavy elements in the capture of very heavy ions at high excitation energies

NASA Astrophysics Data System (ADS)

Royer, G.

2013-05-01

The potential barriers governing the reactions 58Fe+244Pu, 238U+64Ni, and 238U+72Ge have been determined from a liquid-drop model taking into account the proximity energy, shell energies, rotational energy, and deformation of the incoming nuclei in the quasimolecular shape valley. Double-humped potential barriers appear in these entrance channels. The external saddle-point corresponds to two touching ellipsoidal nuclei when the shell and pairing effects are taken into account, while the inner barrier is due to the shell effects at the vicinity of the spherical shape of the composite system. Between them, a large potential pocket exists and persists at very high angular momenta allowing the capture of very heavy ions at high excitation energies.

ECCO: Th/U/Pu/Cm Dating of Galactic Cosmic Ray Nuclei

NASA Technical Reports Server (NTRS)

Westphal, A. J.; Weaver, B. A.; Solarz, M.; Dominquez, G.; Craig, N.; Adams, J. H.; Barbier, L. M.; Christian, E. R.; Mitchell, J. W.; Binns, W. R.;

Role of constant value of surface diffuseness in alpha decay half-lives of superheavy nuclei

NASA Astrophysics Data System (ADS)

Dehghani, V.; Alavi, S. A.; Benam, Kh.

2018-05-01

By using WKB method and considering deformed Woods-Saxon nuclear potential, deformed Coulomb potential, and centrifugal potential, the alpha decay half-lives of 68 superheavy alpha emitters have been calculated. The effect of the constant value of surface diffuseness parameter in the range of 0.1 ≤ a ≤ 0.9 (fm) on the potential barrier, tunneling probability, assault frequency, and alpha decay half-lives has been investigated. Significant differences were observed for alpha decay half-lives and decay quantities in this range of surface diffuseness. Good agreement between calculated half-lives with fitted surface diffuseness parameter a = 0.54 (fm) and experiment was observed.

Recent {alpha} decay half-lives and analytic expression predictions including superheavy nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Royer, G.; Zhang, H. F.

New recent experimental {alpha} decay half-lives have been compared with the results obtained from previously proposed formulas depending only on the mass and charge numbers of the {alpha} emitter and the Q{sub {alpha}} value. For the heaviest nuclei they are also compared with calculations using the Density-Dependent M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulas. The correct agreement allows us to make predictions for the {alpha} decay half-lives of other still unknown superheavy nuclei from these analytic formulas using the extrapolated Q{sub {alpha}} of G. Audi, A. H. Wapstra, and C. Thibault [Nucl. Phys. A729, 337 (2003)].

Alpha Decay Potential Barriers and Half-Lives and Analytical Formula Predictions for Superheavy Nuclei

NASA Astrophysics Data System (ADS)

Royer, Guy; Zhang, Hongfei

The α decay potential barriers are determined in the cluster-like shape path within a generalized liquid drop model including the proximity effects between the α particle and the daughter nucleus and adjusted to reproduce the experimental Qα. The α emission half-lives are determined within the WKB penetration probability. Calculations using previously proposed formulae depending only on the mass and charge of the alpha emitter and Qα are also compared with new experimental alpha-decay half-lives. The agreement allows to provide predictions for the α decay half-lives of other still unknown superheavy nuclei using the Qα determined from the 2003 atomic mass evaluation of Audi, Wapstra and Thibault.

High-K Isomers in Light Superheavy Nuclei by PNC-CSM method

NASA Astrophysics Data System (ADS)

He, Xiao-Tao

2018-05-01

The high-K isomeric states in light superheavy nuclei around A = 250 mass region are investigated by the Cranked Shell Model (CSM) with pairing treated by a Particle-Number Conserving (PNC) method. With including the higher-order deformation ɛ6, both of the high-K multi-particle state energies and the rotational bands in 254No and N = 150 isotone are reproduced well. The isomeric state energies and the microscopic mechanism of kinematic moment of inertia variations versus rotational frequency are discussed. The irregularity of the two-neutron Kπ = 8- state band at ħω ≈ 0:17 in 252No is caused by the configuration mixing with the two-proton Kπ = 8- band. .

Isospin dependence of fragment spectra in heavy/super-heavy colliding nuclei at intermediate energies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chugh, Rajiv, E-mail: rajivchug@gmail.com; Kumar, Rohit, E-mail: rohitksharma.pu@gmail.com; Vinayak, Karan Singh, E-mail: drksvinayak@gmail.com

2016-05-06

Using isospin-dependent quantum molecular dynamics (IQMD) approach, we performed a theoretical investigation of the evolution of various kinds of fragments in heavy and superheavy-ion reactions in the intermediate/medium energy domain. We demonstrated direct impact of symmetry energy and Coulomb interactions on the evolution of fragments. Final fragment spectra (yields) obtained from the analysis of various heavy/super-heavy ion reactions at different reaction conditions show high sensitivity towards Coulomb interactions and less significant sensitivity to symmetry energy forms. No inconsistent pattern of fragment structure is obtained in case of super-heavy ion involved reactions for all the parameterizations of density dependence of symmetrymore » energy.« less

New Fragment Separation Technology for Superheavy Element Research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shaughnessy, D A; Moody, K J; Henderson, R A

2008-01-28

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 physicallymore » 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 {sup 244}Pu+{sup 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 the efficiency of transporting products from the target chamber to the detector array was much too low for applications in heavy element experiments where production rates are on the order of one atom per day or less. Work continues on the MASHA separator, and once the efficiency has been improved, we plan to continue our work on the Pu target for future element 114 experiments. Due to the delays of the MASHA separator, work on establishing the identity of heavy element species produced through nuclear reactions focused instead on chemical separations. In particular, element 115 decays through a series of alpha decays, terminating with an element 105 isotope with a long half-life ({approx} 1 day). By chemically separating the element 105 daughter and observing its subsequent fission decay, the identity of the original parent nucleus can be established through the genetic correlation of the initial series of alpha decays. Chemical separations of element 105 were developed in Switzerland, Russia, and at LLNL. Over the course of two experiments, reaction products from the {sup 243}Am+{sup 48}Ca reaction were collected in a copper block and subsequently processed for chemical separation of the Group Five elements [8,9,13,15]. The Group Five elements were initially separated from the Group Four species, and then the samples were sub-divided into tantalum and niobium fractions. All of the fission events were observed in the tantalum fractions, which implied that element 105 behaved more like tantalum under the chemical conditions of these experiments. These experiments were very successful, and not only demonstrated that chemical separation could be performed on single atoms of interest, but also lent proof to the identity of the parent nucleus as element 115. Subsequent analysis of the alpha spectra taken during the experiment further prove that the fission events observed during the two experiments came from element 105 as the decay daughter of element 115 and could not attributed to interference from other background species [16]. The final aspect of this project was the production of new isotopes and elements. All of the experiments were performed in Dubna at the U400 Cyclotron and the results are described in more detail in Refs. [2,3,5-8,11,12,14]. The first experiments were designed to establish the decay properties of isotopes of elements 112, 114, and 116 [5]. Because these isotopic signatures were established through these initial experiments, the discovery of element 118 [11] was possible, since the 118 nuclides decayed into these previously studied isotopes. This was the first successful report of the discovery of element 118, which was reported by the media to a large extent. The last experiment that was performed for this project was the production and detection of a new isotope of element 113 [14].« less

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

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Safoora, V.

2017-11-01

The probable projectile-target combinations for the synthesis of superheavy nucleus 296Lv found in the cold valley of 296Lv have been identified by studying the interaction barrier of the colliding nuclei, probability of compound nucleus formation, P_{CN}, and survival probability W_{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 48Ca+248Cm is found to be the most probable projectile-target pair for the synthesis of 296Lv. The calculated maximum value of 2n, 3n, 4n and 5n channel cross section for the reaction 48Ca+248Cm 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 291-295,298Lv using 48Ca projectile on 243-247,250Cm targets are calculated. Among these reactions, the reactions 48Ca+247Cm → 295Lv and 48Ca+250Cm → 298Lv 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 48Ca+245Cm → 293Lv and 48Ca+248Cm → 296Lv 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.

Monopoles, cosmology, and astrophysics - Update 1985

NASA Technical Reports Server (NTRS)

Turner, Michael S.

1986-01-01

The characteristics of the superheavy magnetic monopoles (MMs) predicted by GUTs are reviewed, and recent developments in astrophysical MM search techniques are surveyed. Theoretical models of the birth, current distribution, and motion of MMs are examined; the observational implications of MM mass, magnetic charge, and ability to catalyze nucleon decay are considered; estimates of the average and local flux limits for MMs of 10 to the 25th eV are given (less than about 3 x 10 to the -15th and less than about 3 x 10 to the -11th/sq cm sr sec, respectively); and the possibility of detecting MMs in the sun (if they can escape annihilation there) is discussed.

Connecting the "Hot Fusion Island" to the Nuclear Mainland: Search for 283,284,285Fl Decay Chains

NASA Astrophysics Data System (ADS)

Rykaczewski, K. P.; Utyonkov, V. K.; Brewer, N. T.; Grzywacz, R. K.; Miernik, K.; Roberto, J. B.; Oganessian, Yu. Ts.; Polyakov, A. N.; Tsyganov, Yu. S.; Voinov, A. A.; Abdullin, F. Sh.; Dmitriev, S. N.; Itkis, M. G.; Sabelnikov, A. V.; Sagaidak, R. N.; Shirokovsky, I. V.; Shumeiko, M. V.; Subbotin, V. G.; Sukhov, A. M.; Vostokin, G. K.; Hamilton, J. H.; Henderson, R. A.; Stoyer, M. A.

The program of studies on superheavy nuclei to identify new isotopes anchoring the decay chains from the Hot Fusion Island to the Nuclear Mainland has been started at the Dubna Gas Filled Recoil Separator (DGFRS, JINR Dubna) in collaboration between Russia, US and Poland. These studies are performed with new detection and digital data acquisition system developed at ORNL (Oak Ridge) and UT (Knoxville). The evidence for fast fission of the new isotope 284Fl is presented. The low cross section for the 3n channel of 239Pu + 48Ca reaction is attributed to lower than expected fission barriers in 287-284Fl.

The Energetic Trans-Iron Nuclei Experiment (ENTICE)

NASA Technical Reports Server (NTRS)

Binns, W. R.; Israel, M. H.; Cummings, A. C.; Labrador, A. W.; Mewaldt, R. A.; Leske, R. A.; Stone, E. C.; Wiedenbeck, M. E.; Christian, E. R.; Denolfo, G. A.;

Detector Calibration to Spontaneous Fission for the Study of Superheavy Elements Using Gas-Filled Recoil Ion Separator

NASA Astrophysics Data System (ADS)

Takeyama, Mirei; Kaji, Daiya; Morimoto, Kouji; Wakabayashi, Yasuo; Tokanai, Fuyuki; Morita, Kosuke

Detector response to spontaneous fission (SF) of heavy nuclides produced in the 206Pb(48Ca,2n)252No reaction was investigated using a gas-filled recoil ion separator (GARIS). Kinetic energy distributions of the SF originating from 252No were observed by tuning implantation depth of evaporation residue (ER) to the detector. The focal plane detector used in the GARIS experiments was well calibrated by comparing with the known total kinetic energy (TKE) of SF due to 252No. The correction value for the TKE calculation was deduced as a function of the implantation depth of 252No to the detector. Furthermore, we have investigated the results by comparing with those obtained by a computer simulation using the particle and heavy ion transport code system (PHITS).

Hawking's A Briefer History of Time's No-God-Universe disproven by primordial ^218Po halos embedded in granite rocks, which proves their rapid creation due to ^218Po's 3 min t1/2, something only the God of Genesis could have done

NASA Astrophysics Data System (ADS)

Gentry, Robert

2011-04-01

Quotes from my Science (184, 62, 1974) report, Radiohalos in Radiochronological and Cosmological Perspective, show why primordial polonium halos earlier commanded attention for creation," It is also apparent that Po halos do pose contradictions to currently held views of Earth history" "For example, there is first the problem of how isotopic separation of several Po isotopes [or their β-decay precursors could have occurred naturally. Second, a straightforward explanation of ^218Po halos implies that the 1-μm radiocenters of very dark halos of this type initially contained as many as 5 x 10^9 atoms (a concentration of more than 50 percent) of the isotope ^218Po (half-life, 3 minutes), a problem that almost defies reason. A further necessary consequence, that such Po halos could have formed only if the host rocks underwent a rapid crystallization, renders exceedingly difficult, in my estimation, the prospect of explaining these halos by physical laws as presently understood." In 1977 E. P. Wigner, G. N. Flerov (Dubna), Ed Anders, E. Segre, F. Dyson, and John Wheeler all commented on these results (see alphacosmos.net). Also, ^14N detection in dwarf radiohalos may be of cosmological significance in implying a superheavy element origin from ^14C emission.

Determination of Fusion Barrier Distributions from Quasielastic Scattering Cross Sections towards Superheavy Nuclei Synthesis

NASA Astrophysics Data System (ADS)

Tanaka, Taiki; Narikiyo, Yoshihiro; Morita, Kosuke; Fujita, Kunihiro; Kaji, Daiya; Morimoto, Kouji; Yamaki, Sayaka; Wakabayashi, Yasuo; Tanaka, Kengo; Takeyama, Mirei; Yoneda, Akira; Haba, Hiromitsu; Komori, Yukiko; Yanou, Shinya; Jean-Paul Gall, Benoît; Asfari, Zouhair; Faure, Hugo; Hasebe, Hiroo; Huang, Minghui; Kanaya, Jumpei; Murakami, Masashi; Yoshida, Atsushi; Yamaguchi, Takayuki; Tokanai, Fuyuki; Yoshida, Tomomi; Yamamoto, Shoya; Yamano, Yuki; Watanabe, Kenyu; Ishizawa, Satoshi; Asai, Masato; Aono, Ryuji; Goto, Shin-ichi; Katori, Kenji; Hagino, Kouichi

2018-01-01

In order to study the nucleus-nucleus interactions for syntheses of superheavy nuclei, we measured excitation functions for the quasielastic scattering of 48Ca+208Pb, 50Ti+208Pb, and 48Ca+248Cm using the gas-filled-type recoil ion separator GARIS. The quasielastic scattering events were clearly separated from deep-inelastic events by using GARIS and its focal plan detectors, except for high-incident-energy points. The quasielastic barrier distributions were successfully extracted for these systems, and compared with coupled-channels calculations. The results of the calculations indicate that vibrational and rotational excitations of the colliding nuclei, as well as neutron transfers before contact, strongly affect the structure of the barrier distribution. For the reactions of 48Ca+208Pb and 50Ti+208Pb, a local maximum of the barrier distribution occurred at the same energy as the peak of the 2n evaporation cross section of the system. On the other hand, for the hot fusion reaction of 48Ca+248Cm, the 4n evaporation cross section of the system peaks at energies well above the maximum of the barrier distribution. This may be attributed to the deformation of the target nucleus. We argue that these findings can be utilized to locate the optimal energy for future searches for undiscovered superheavy nuclei.

NUCLEAR AND HEAVY ION PHYSICS: α-decay half-lives of superheavy nuclei and general predictions

NASA Astrophysics Data System (ADS)

Dong, Jian-Min; Zhang, Hong-Fei; Wang, Yan-Zhao; Zuo, Wei; Su, Xin-Ning; Li, Jun-Qing

2009-08-01

The generalized liquid drop model (GLDM) and the cluster model have been employed to calculate the α-decay half-lives of superheavy nuclei (SHN) using the experimental α-decay Q values. The results of the cluster model are slightly poorer than those from the GLDM if experimental Q values are used. The prediction powers of these two models with theoretical Q values from Audi et al. (QAudi) and Muntian et al. (QM) have been tested to find that the cluster model with QAudi and QM could provide reliable results for Z > 112 but the GLDM with QAudi for Z <= 112. The half-lives of some still unknown nuclei are predicted by these two models and these results may be useful for future experimental assignment and identification.

Multinucleon transfer reactions – a pathway to new heavy and superheavy nuclei?

NASA Astrophysics Data System (ADS)

Heinz, Sophie

2018-05-01

Recently, we reported the observation of several new neutron-deficient isotopes with proton numbers Z ≥ 92 in collisions of 48Ca + 248Cm at the Coulomb barrier. The peculiarity is that these nuclei were produced in deep inelastic multinucleon transfer reactions, a method which is presently discussed as a possible new pathway to enter so far unknown regions in the upper part of the Chart of Nuclides. Of particular interest are multinucleon transfer reactions as a possible means to produce neutron-rich superheavy nuclei and nuclei along the magic neutron shell N = 126. Based on present-day physical and technical state-of-the art, we will discuss the question how big are our chances to enter these regions by applying multinucleon transfer reactions.

Possibility of synthesizing a doubly magic superheavy nucleus

NASA Astrophysics Data System (ADS)

Aritomo, Y.

2007-02-01

The possibility of synthesizing a doubly magic superheavy nucleus, 298114184, is investigated on the basis of fluctuation-dissipation dynamics. In order to synthesize this nucleus, we must generate more neutron-rich compound nuclei because of the neutron emissions from excited compound nuclei. The compound nucleus 304114 has two advantages to achieving a high survival probability. First, because of low neutron separation energy and rapid cooling, the shell correction energy recovers quickly. Secondly, owing to neutron emissions, the neutron number in the nucleus approaches that of the double closed shell and the nucleus attains a large fission barrier. Because of these two effects, the survival probability of 304114 does not decrease until the excitation energy E*=50 MeV. These properties lead to a rather high evaporation residue cross section.

Relativity-Induced Bonding Pattern Change in Coinage Metal Dimers M2 (M = Cu, Ag, Au, Rg).

PubMed

Li, Wan-Lu; Lu, Jun-Bo; Wang, Zhen-Ling; Hu, Han-Shi; Li, Jun

2018-05-07

The periodic table provides a fundamental protocol for qualitatively classifying and predicting chemical properties based on periodicity. While the periodic law of chemical elements had already been rationalized within the framework of the nonrelativistic description of chemistry with quantum mechanics, this law was later known to be affected significantly by relativity. We here report a systematic theoretical study on the chemical bonding pattern change in the coinage metal dimers (Cu 2 , Ag 2 , Au 2 , Rg 2 ) due to the relativistic effect on the superheavy elements. Unlike the lighter congeners basically demonstrating ns- ns bonding character and a 0 g + ground state, Rg 2 shows unique 6d-6d bonding induced by strong relativity. Because of relativistic spin-orbit (SO) coupling effect in Rg 2 , two nearly degenerate SO states, 0 g + and 2 u , exist as candidate of the ground state. This relativity-induced change of bonding mechanism gives rise to various unique alteration of chemical properties compared with the lighter dimers, including higher intrinsic bond energy, force constant, and nuclear shielding. Our work thus provides a rather simple but clear-cut example, where the chemical bonding picture is significantly changed by relativistic effect, demonstrating the modified periodic law in heavy-element chemistry.

Aurel Sandulescu—a life dedicated to nuclear physics

NASA Astrophysics Data System (ADS)

Liotta, R. J.

2013-02-01

I was surprised to receive an invitation letter from Andrei Dorobantu, whom I did not know, to give a talk about pairing excitations at the Predeal International School of 1978, which I accepted. This was the first time that I would visit Romania, and I knew very little about the research that was performed in the country. In my talk I was showing the role of the pairing mode in a rather popular theory at that time which was called Nuclear Field Theory. Suddenly I was interrupted in a rather brusque fashion by a man with an acute and loud voice, telling me that it has been shown by somebody that the Nuclear Field Theory does not converge. I was very upset by this interruption, particularly because he was right. I told him this and asked him to wait up at the end of my talk. During the coffee break the man came to me and presented himself. It was the first time I came into contact with the extraordinary person that is Aurel Sandulescu. During the coffee break we spoke about his research, especially in alpha decay. I was interested in this subject because just then I had started to perform calculations in relation to experiments carried out at my Institution in Stockholm, which at that time was called the Research Institute of Physics. We continued with our discussions during the whole duration of the School, often with his wife, Violeta, present. I became amazed by the extensive work he had done since the late 1950s on microscopic treatments of alpha decay. He had studied the decay of both normal and superfluid as well as spherical and deformed nuclei, all within the framework of the shell model or its BCS equivalent. I was very enthusiastic about this, since I was convinced that one should, in principle, be able to describe the decay process by using a shell model representation. I was disappointed to realize that he did not agree with me. I insisted that from a purely theoretical point of view the shell model was, rather more than a model, an excellent representation to describe nuclear processes. However, with the perspective that the passing years provides, I have since had to admit that one needs cluster components in the shell model wave functions in order to properly describe the clustering and subsequent decay. For Aurel, this realization led him to consider the decay as a fission process. It was through this that he found, just by simply looking through the penetrability, that cluster radioactivity is a valid form of decay, as was indeed confirmed experimentally several years afterwards. This new form of radioactive decay has had a profound influence on nuclear physics. It opened the way to the investigation of the structure and exotic forms that superheavy nuclei may acquire, since one expects that heavy clusters are likely to be emitted from these nuclei. The importance of cluster decay, and the theory behind its discovery, is of great relevance even today. This can be attested, for example, by the recent prediction of Poenaru, Gherghescu and Greiner (2011 Phys. Rev. Lett 107 062503) that in some superheavy nuclei this form of decay is dominant even over alpha emission, thus making cluster decay a powerful tool in the detection of superheavy nuclei. The description of cluster decay as a fragmentation process and its relation to heavy and superheavy elements was a natural extension of the research that Aurel Sandulescu was conducting at that time. Just before the cluster decay paper appeared he addressed the important question of the production of superheavy elements. The straightforward method of reaching this is by heavy ions collisions, but the question was: which nuclei should one use as reaction partners? Sandulescu proposed choosing those nuclei that provide a minimum of the potential energy, which was an important step in the synthesis of superheavy nuclei. Another subject which is of great importance in nuclear physics and in which Sandulescu played a crucial role was his prediction of neutronless spontaneous binary and ternary fission. He was so elated and eager about this that he even contributed to the experimental discovery of this rare phenomenon. Since then, there have been many theoretical as well as experimental studies performed in this and similar subjects related to cold fission processes. Particularly relevant in the framework of this conference are his studies on the damping of collective modes in deep inelastic collisions. He treated this difficult subject by extending a formalism derived for open systems to nuclear collective motions. The master equation that he thus obtained describes well the dynamics of degrees of freedom not only in the damping of excited nuclear states, but also particularly in heavy ion collisions and in the decaying of the most collective states in nuclear physics—giant resonances. He has also analyzed the complicated mechanisms that induce the clustering of nucleons, which led to his realization that the cluster structure can be viewed as solitons moving on the nuclear surface. This intense scientific work was followed by other related activities. In Romania he became a full professor in 1970, a corresponding member of the Romanian Academy of Sciences in 1991, an ordinary member in 1992 and Vice President in the period 1994-1998. Most remarkable is that he tried to influence the development of Science in the country by himself becoming a politician. Thus, he was a member of the Romanian Parliament in the period 1996-2000. Outside of Romania he has also undertaken remarkable activities. He has been Invited Scientist and Invited Professor to many institutions around the world. One should mention in particular his position as Vice Director of the Joint Institute of Nuclear Research, Dubna, Russia, in the period 1983-1986. He has proceeded through all these endeavors by attracting many foreign scientists to Romania, including myself. But especially important was his influence upon students, many of whom are today recognized physicists and leaders of Romanian physics. It is in recognition of his contribution to physics, especially nuclear physics, as well as his work for Romanian science that this School is organized in his honour, on the occasion of his 80th birthday. I cannot finish this short account without mentioning the person that accompanied Aurel Sandulescu through all his life, his wife of more than fifty years, Violeta. She also was an exceptional person. In her youth she was a very dedicated sporty girl, very athletic, very courageous, very fair and, above all, very generous. These qualities remained with her throughout her life. With deep sorrow I learnt that she passed away three months ago, still youthful and enthusiastic. R J Liotta

Primordial heating of asteroidal parent bodies

NASA Technical Reports Server (NTRS)

Sonett, C. P.; Reynolds, R. T.

1979-01-01

Most meteorites show evidence of thermal processing either because of metamorphic changes or as a result of melting and differentiation. Proposed mechanisms for supplying this energy generally rely upon short-lived radioisotopes or electrical induction, though accretion is sometimes mentioned, and more exotic models have been discussed. Interest in isotopic heating has been heightened by the discovery of Al-26 in Allende inclusions and also by the proposal that a lunar core and dynamo resulted from the radioactive decay of superheavy elements during the early solar system. Electrical induction as a heat source can be scaled to a broad range of solar system conditions, but corroborative evidence for these conditions is inconclusive. The accretion mechanism is probably not viable for the asteroidal and meteorite parent bodies, because the high kinetic energy requirement is inconsistent with the formation of the objects and their regoliths in the presence of a weak gravitational field.

Science requirements for Heavy Nuclei Collection (HNC) experiment on NASA Long Duration Exposure Facility (LDEF) Mission 2

NASA Technical Reports Server (NTRS)

Price, P. Buford

1991-01-01

The Heavy Nuclei Collection (HNC) is a passive array of stacks of a special glass, 14 sheets thick, that record tracks of ultraheavy cosmic rays for later readout by automated systems on Earth. The primary goal is to determine the relative abundances of both the odd- and even-Z cosmic rays with Z equal to or greater than 50 with statistics a factor at least 60 greater than obtained in HEAO-3 and to obtain charge resolution at least as good as 0.25 charge unit. The secondary goal is to search for hypothetical particles such as superheavy elements. The HNC detector array will have a cumulative collection power equivalent to flying 32 sq m of detectors in space for 4 years. The array will be flown as a free-flight spacecraft and/or attached to Space Station Freedom.

The Munich accelerator for fission fragments MAFF

NASA Astrophysics Data System (ADS)

Habs, D.; Groß, M.; Assmann, W.; Ames, F.; Bongers, H.; Emhofer, S.; Heinz, S.; Henry, S.; Kester, O.; Neumayr, J.; Ospald, F.; Reiter, P.; Sieber, T.; Szerypo, J.; Thirolf, P. G.; Varentsov, V.; Wilfart, T.; Faestermann, T.; Krücken, R.; Maier-Komor, P.

2003-05-01

The Munich Accelerator for Fission Fragments MAFF has been designed for the new Munich research reactor FRM-II. It will deliver several intense beams (˜3×10 11 s -1) of very neutron-rich fission fragments with a final energy of 30 keV (low-energy beam) or energies between 3.7 and 5.9 MeV· A (high-energy beam). Such beams are of interest for the creation of super-heavy elements by fusion reactions, nuclear spectroscopy of exotic nuclei, but they also have a potential for applications, e.g. in medicine. Presently the Munich research reactor FRM-II is ready for operation, but authorities delay the final permission to turn the reactor critical probably till the end of 2002. Only after this final permission the financing of the major parts of MAFF can start. On the other hand all major components have been designed and special components have been tested in separate setups.

Analysis of decay chains of superheavy nuclei produced in the 249Bk+48Ca and 243Am+48Ca reactions

NASA Astrophysics Data System (ADS)

Zlokazov, V. B.; Utyonkov, V. K.

2017-07-01

The analysis of decay chains starting at superheavy nuclei 293Ts and 289Mc is presented. The spectroscopic properties of nuclei identified during the experiments using the 249Bk+48Ca and 243Am+48Ca reactions studied at the gas-filled separators DGFRS, TASCA and BGS are considered. We present the analysis of decay data using widely adopted statistical methods and applying them to the short decay chains of parent odd-Z nuclei. We find out that the recently suggested method of analyzing decay chains by Forsberg et al may lead to questionable conclusions when applied for the analysis of radioactive decays. Our discussion demonstrates reasonable congruence of α-particle energies and decay times of nuclei assigned to isotopes 289Mc, 285Nh and 281Rg observed in both reactions.

Physics of superheavy dark matter in supergravity

NASA Astrophysics Data System (ADS)

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.

The Energetic Trans-Iron Cosmic-ray Experiment (ENTICE)

NASA Technical Reports Server (NTRS)

Binns, W. R.; Adams. J. H.; Barghouty, A. F.; Christian, E. R.; Cummings, A. C.; Hams, T.; Israel, M. H.; Labrador, A. W.; Leske, R. A.; Link, J. T.;

Realtime processing of LOFAR data for the detection of nano-second pulses from the Moon

NASA Astrophysics Data System (ADS)

Winchen, T.; Bonardi, A.; Buitink, S.; Corstanje, A.; Enriquez, J. E.; Falcke, H.; Hörandel, J. R.; Mitra, P.; Mulrey, K.; Nelles, A.; Rachen, J. P.; Rossetto, L.; Schellart, P.; Scholten, O.; Thoudam, S.; Trinh, T. N. G.; ter Veen, S.; KSP, The LOFAR Cosmic Ray

2017-10-01

The low flux of the ultra-high energy cosmic rays (UHECR) at the highest energies provides a challenge to answer the long standing question about their origin and nature. Even lower fluxes of neutrinos with energies above 1022 eV are predicted in certain Grand-Unifying-Theories (GUTs) and e.g. models for super-heavy dark matter (SHDM). The significant increase in detector volume required to detect these particles can be achieved by searching for the nanosecond radio pulses that are emitted when a particle interacts in Earth’s moon with current and future radio telescopes. In this contribution we present the design of an online analysis and trigger pipeline for the detection of nano-second pulses with the LOFAR radio telescope. The most important steps of the processing pipeline are digital focusing of the antennas towards the Moon, correction of the signal for ionospheric dispersion, and synthesis of the time-domain signal from the polyphased-filtered signal in frequency domain. The implementation of the pipeline on a GPU/CPU cluster will be discussed together with the computing performance of the prototype.

Manifestation of the structure of heavy nuclei in their alpha decays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adamian, G. G., E-mail: adamian@theor.jinr.ru; Antonenko, N. V.; Bezbakh, A. N.

2016-11-15

Low-lying one- and two-quasiparticle states of heavy nuclei are predicted. Alpha-decay chains, including those that proceed through isomeric states, are examined on the basis of the predicted properties of superheavy nuclei.

Nuclear inertia and the decay modes of superheavy nuclei

NASA Astrophysics Data System (ADS)

Poenaru, D. N.; Gherghescu, R. A.; Greiner, Walter

2013-10-01

Superheavy nuclei produced up to now decay mainly by α emission and spontaneous fission. For atomic numbers larger than 121 cluster decay has a good chance to compete. While calculated α decay half-lives are in agreement with experimental data within one order of magnitude and cluster decay experiments are also very well accounted for, the discrepancy between theory and experiment can be as high as ten orders of magnitude for spontaneous fission. We analyze some ways of improving the accuracy: using a semiempirical formula for α decay and changing the parameters of analytical superasymmetric fission and of the universal curve for cluster decay. For spontaneous fission we act on nuclear dynamics based on potential barriers computed by the macroscopic-microscopic method and employing various nuclear inertia variation laws. Applications are illustrated for 284Cn and Z = 118-124 even-even parent nuclei. Communicated by Steffen Bass

Superheavy dark matter through Higgs portal operators

NASA Astrophysics Data System (ADS)

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.

Study of Cold Fusion Reactions Using Collective Clusterization Approach

NASA Astrophysics Data System (ADS)

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

2017-10-01

Within the framework of the dynamical cluster decay model (DCM), the 1n evaporation cross-sections ({σ }1n) of cold fusion reactions (Pb and Bi targets) are calculated for {Z}{CN}=104-113 superheavy nuclei. The calculations are carried out in the fixed range of excitation energy {E}{CN}* =15+/- 1 {MeV}, so that the comparative analysis of reaction dynamics can be worked out. First of all, the fission barriers (B f ) and neutron separation energies ({S}1n) are estimated to account the decreasing cross-sections of cold fusion reactions. In addition to this, the importance of hot optimum orientations of β 2i-deformed nuclei over cold one is explored at fixed angular momentum and neck-length parameters. The hot optimum orientations support all the target-projectile (t,p) combinations, which are explored experimentally in the cold fusion reactions. Some new target-projectile combinations are also predicted for future exploration. Further, the 1n cross-sections are addressed for {Z}{CN}=104-113 superheavy nuclei at comparable excitation energies which show the decent agrement with experimental data upto {Z}{CN}=109 nuclei. Finally, to understand the dynamics of higher-Z superheavy nuclei, the cross-sections are also calculated at maximum available energies around the Coulomb barrier and the effect of non-sticking moment of inertia ({I}{NS}) is also investigated at these energies. Supported by the Council of Scientific and Industrial Research (CSIR), in the Form of Research Project Grant No. 03(1341)/15/EMR-II, and to DST, New Delhi, for INSPIRE-Fellowship Grant No. DST/INSPIRE/03/2015/000199

Dark matter candidates

NASA Technical Reports Server (NTRS)

Turner, Michael S.

1989-01-01

The types of particles which may provide the nonluminous mass required by big-bang cosmological models are listed and briefly characterized. The observational evidence for the existence of dark matter (outweighing the luminous component by at least a factor of 10) is reviewed; the theoretical arguments favoring mainly nonbaryonic dark matter are summarized; and particular attention is given to weakly interacting massive particles (WIMPs) remaining as relics from the early universe. The WIMPs are classified as thermal relics (heavy stable neutrinos and lighter neutralinos), asymmetric relics (including baryons), nonthermal relics (superheavy magnetic monopoles, axions, and soliton stars), and truly exotic relics (relativistic debris or vacuum energy). Explanations for the current apparent baryon/exotica ratio of about 0.1 in different theoretical scenarios are considered, and the problems of experimental and/or observational dark-matter detection are examined.

Relativistic effects for the reaction Sg + 6 CO → Sg(CO){sub 6}: Prediction of the mean bond energy, atomization energy, and existence of the first organometallic transactinide superheavy hexacarbonyl Sg(CO){sub 6}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malli, Gulzari L., E-mail: malli@sfu.ca

2015-02-14

Our ab initio all-electron fully relativistic Dirac–Fock (DF) and nonrelativistic (NR) Hartree-Fock calculations predict the DF relativistic and NR energies for the reaction: Sg + 6 CO → Sg(CO){sub 6} as −7.39 and −6.96 eV, respectively, i.e., our calculated ground state total DF relativistic and NR energies for the reaction product Sg(CO){sub 6} are lower by 7.39 and 6.96 eV than the total DF and NR ground state energies of the reactants, viz., one Sg atom plus six CO molecules, respectively. Our calculated DF relativistic and NR atomization energies (Ae) are 65.23 and 64.82 eV, respectively, and so the contributionmore » of relativistic effects to the Ae of ∼0.40 eV is marginal. The Sg–C and C–O optimized bond distances for the octahedral geometry as calculated in our DF (NR) calculations are 2.151 (2.318 Å) and 1.119 (1.114 Å), respectively. The BSSE correction calculated using the DIRAC code ∼14 kcal/mol. The relativistic DF and NR mean energies predicted by us are 118.8 and 111.9 kJ/mol, respectively, and the contribution of ∼7 kJ/mol due to relativistic effects to the mean energy of Sg(CO){sub 6} is negligible. Ours are the first calculations of the relativistic effects for the atomization energy, mean bond energy, and energy of the reaction for possible formation of Sg(CO){sub 6}, and both our relativistic DF and the NR treatments clearly predict for the first time the existence of hexacarbonyl of the transactinide superheavy element seaborgium Sg. In conclusion, relativistic effects are not significant for Sg(CO){sub 6}.« less

High-accuracy mass spectrometry for fundamental studies.

PubMed

Kluge, H-Jürgen

2010-01-01

Mass spectrometry for fundamental studies in metrology and atomic, nuclear and particle physics requires extreme sensitivity and efficiency as well as ultimate resolving power and accuracy. An overview will be given on the global status of high-accuracy mass spectrometry for fundamental physics and metrology. Three quite different examples of modern mass spectrometric experiments in physics are presented: (i) the retardation spectrometer KATRIN at the Forschungszentrum Karlsruhe, employing electrostatic filtering in combination with magnetic-adiabatic collimation-the biggest mass spectrometer for determining the smallest mass, i.e. the mass of the electron anti-neutrino, (ii) the Experimental Cooler-Storage Ring at GSI-a mass spectrometer of medium size, relative to other accelerators, for determining medium-heavy masses and (iii) the Penning trap facility, SHIPTRAP, at GSI-the smallest mass spectrometer for determining the heaviest masses, those of super-heavy elements. Finally, a short view into the future will address the GSI project HITRAP at GSI for fundamental studies with highly-charged ions.

Adsorption of the astatine species on a gold surface: A relativistic density functional theory study

NASA Astrophysics Data System (ADS)

Demidov, Yuriy; Zaitsevskii, Andréi

2018-01-01

We report first-principle based studies of the adsorption interaction of astatine species on a gold surface. These studies are aimed primarily at the support and interpretation of gas chromatographic experiments with superheavy elements, tennessine (Ts, Z = 117), a heavier homologue of At, and possibly its pseudo-homologue nihonium (Nh, Z = 113). We use gold clusters with up to 69 atoms to simulate the adsorption sites and estimate the desorption energies of At & AtOH from a stable gold (1 1 1) surface. To describe the electronic structure of At -Aun and AtOH -Aun complexes, we combine accurate shape-consistent relativistic pseudopotentials and non-collinear two-component relativistic density functional theory. The predicted desorption energies of At and AtOH on gold are 130 ± 10 kJ/mol and 90 ± 10 kJ/mol, respectively. These results confirm the validity of the estimates derived from chromatographic data (147 ± 15 kJ/mol for At, and 100-10+20 kJ/mol for AtOH).

Microscopic heavy-ion theory. Final Report. February 2014-June 2015

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ernst, David J.; Oberacker, Volker E.; Umar, A. Sait

The Vanderbilt nuclear theory group conducts research in the areas of low-energy nuclear reactions and in neutrino oscillations. Specically, we study dynamics of nuclear reactions microscopically, in particular for neutron-rich nuclei which will be accessible with current and future radioactive ion beam facilities. The neutrino work concentrates on constructing computational tools for analyzing neutrino oscillation data. The most important of these is the analysis of the Super K atmospheric data. Our research concentrates on the following topics which are part of the DOE Long-Range Plan: STUDIES OF LOW-ENERGY REACTIONS OF EXOTIC NUCLEI (Professors Umar and Oberacker), including sub-barrier fusion crossmore » sections, capture cross sections for superheavy element production, and nuclear astrophysics applications. Our theory project is strongly connected to experiments at RIB facilities around the world, including NSCL-FRIB (MSU) and ATLAS-CARIBU (Argonne). PHENOMENOLOGY OF NEUTRINO OSCILLATIONS (Prof. Ernst), extracting information from existing neutrino oscillation experiments and proposing possible future experiments in order to better understand the oscillation phenomenon.« less

Systematic study of fission barriers of excited superheavy nuclei

NASA Astrophysics Data System (ADS)

Sheikh, J. A.; Nazarewicz, W.; Pei, J. C.

2009-07-01

A systematic study of fission-barrier dependence on excitation energy has been performed using the self-consistent finite-temperature Hartree-Fock + BCS (FT-HF + BCS) formalism with the SkM* Skyrme energy density functional. The calculations have been carried out for even-even superheavy nuclei with Z ranging between 110 and 124. For an accurate description of fission pathways, the effects of triaxial and reflection-asymmetric degrees of freedom have been fully incorporated. Our survey demonstrates that the dependence of isentropic fission barriers on excitation energy changes rapidly with particle number, pointing to the importance of shell effects even at large excitation energies characteristic of compound nuclei. The fastest decrease of fission barriers with excitation energy is predicted for deformed nuclei around N=164 and spherical nuclei around N=184 that are strongly stabilized by ground-state shell effects. For the nuclei Pu240 and Fm256, which exhibit asymmetric spontaneous fission, our calculations predict a transition to symmetric fission at high excitation energies owing to the thermal quenching of static reflection asymmetric deformations.

Synthesis, Decay Properties, and Identification of Superheavy Nuclei Produced in 48Ca-induced Reactions

NASA Astrophysics Data System (ADS)

Oganessian, Yu. Ts.; Utyonkov, V. K.; Lobanov, Yu. V.; Abdullin, F. Sh.; Polyakov, A. N.; Sagaidak, R. N.; Shirokovsky, I. V.; Tsyganov, Yu. S.; Voinov, A. A.; Iliev, S.; Subbotin, V. G.; Sukhov, A. M.; Gulbekian, G. G.; Bogomolov, S. L.; Gikal, B. N.; Mezentsev, A. N.; Subotic, K.; Zagrebaev, V. I.; Itkis, M. G.; Moody, K. J.; Henderson, R. A.; Patin, J. B.; Shaughnessy, D. A.; Stoyer, M. A.; Stoyer, N. J.; Wilk, P. A.; Kenneally, J. M.; Landrum, J. H.; Wild, J. F.; Lougheed, R. W.

2007-10-01

Thirty-four new nuclides with Z = 104-116, 118 and N = 161-177 have been synthesized in the complete-fusion reactions of 238U, 237Np, 242,244Pu, 243Am, 245,248Cm, and 249Cf targets with 48Ca beams. The masses of evaporation residues were identified through measurements of the excitation functions of the xn-evaporation channels and from cross bombardments. The decay properties of the new nuclei agree with those of previously known heavy nuclei and with predictions from different theoretical models. A discussion of self-consistent interpretations of all observed decay chains originating from the parent isotopes 282,283112, 282113, 286-289114, 287,288115, 290-293116, and 294118 is presented. Decay energies and lifetimes of the neutron-rich superheavy nuclei as well as their production cross sections indicate a considerable increase in the stability of nuclei with the approach to the theoretically predicted nuclear shells with N = 184 and Z = 114.

Synthesis, Decay Properties, and Identification of Superheavy Nuclei Produced in 48CA-INDUCED Reactions

NASA Astrophysics Data System (ADS)

Oganessian, Yu. Ts.; Utyonkov, V. K.; Lobanov, Yu. V.; Abdullin, F. Sh.; Polyakov, A. N.; Sagaidak, R. N.; Shirokovsky, I. V.; Tsyganov, Yu. S.; Voinov, A. A.; Iliev, S.; Subbotin, V. G.; Sukhov, A. M.; Gulbekian, G. G.; Bogomolov, S. L.; Gikal, B. N.; Mezentsev, A. N.; Subotic, K.; Zagrebaev, V. I.; Itkis, M. G.; Moody, K. J.; Henderson, R. A.; Patin, J. B.; Shaughnessy, D. A.; Stoyer, M. A.; Stoyer, N. J.; Wilk, P. A.; Kenneally, J. M.; Landrum, J. H.; Wild, J. F.; Lougheed, R. W.

2008-04-01

Thirty-four new nuclides with Z = 104-116, 118 and N = 161-177 have been synthesized in the complete-fusion reactions of 238U, 237Np, 242,244Pu, 243Am, 245,248Cm, and 249Cf targets with 48Ca beams. The masses of evaporation residues were identified through measurements of the excitation functions of the xn-evaporation channels and from cross bombardments. The decay properties of the new nuclei agree with those of previously known heavy nuclei and with predictions from different theoretical models. A discussion of self-consistent interpretations of all observed decay chains originating from the parent isotopes 282,283112, 282113, 286-289114, 287,288115, 290-293116, and 294118 is presented. Decay energies and lifetimes of the neutron-rich superheavy nuclei as well as their production cross sections indicate a considerable increase in the stability of nuclei with the approach to the theoretically predicted nuclear shells with N = 184 and Z = 114.

Octupole deformations in high-K isomeric states of heavy and superheavy nuclei

NASA Astrophysics Data System (ADS)

Minkov, N.; Walker, P. M.

2016-01-01

We study the effects of quadrupole-octupole deformations on the energy and magnetic properties of high-K isomeric states in even-even heavy and superheavy nuclei. The neutron two-quasiparticle (2qp) isomeric energies and magnetic dipole moments are calculated within a deformed shell model with the Bardeen-Cooper- Schrieffer (BCS) pairing interaction over a wide range of quadrupole and octupole deformations. We found that in most cases the magnetic moments exhibit a pronounced sensitivity to the octupole deformation, while the 2qp energies indicate regions of nuclei in which the presence of high-K isomeric states may be associated with the presence of octupole softness or even with octupole deformation. In the present work we also examine the influence of the BCS pairing strength on the energy of the blocked isomer configuration. We show that the formation of 2qp energy minima in the space of quadrupole-octupole and eventually higher multipolarity deformations is a subtle effect depending on nuclear pairing correlations.

Nuclear spectroscopy with Geant4. The superheavy challenge

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Lunar and Planetary Science XXXV: Meteorites

NASA Technical Reports Server (NTRS)

2004-01-01

The session "Meteorites" included the following reports:Description of a New Stony Meteorite Find from Bulloch County, Georgia; Meteorite Ablation Derived from Cosmic Ray Track Data Dhofar 732: A Mg-rich Orthopyroxenitic Achondrite Halogens, Carbon and Sulfur in the Tagish Lake Meteorite: Implications for Classification and Terrestrial Alteration; Electromagnetic Scrape of Meteorites and Probably Columbia Tiles; Pre-Atmospheric Sizes and Orbits of Several Chondrites; Research of Shock-Thermal History of the Enstatite Chondrites by Track, Thermoluminescence and Neutron-Activation (NAA) Methods; Radiation and Shock-thermal History of the Kaidun CR2 Chondrite Glass Inclusions; On the Problem of Search for Super-Heavy Element Traces in the Meteorites: Probability of Their Discovery by Three-Prong Tracks due to Nuclear Spontaneous Fission Trace Element Abundances in Separated Phases of Pesyanoe, Enstatite Achondrite; Evaluation of Cooling Rate Calculated by Diffusional Modification of Chemical Zoning: Different Initial Profiles for Diffusion Calculation; Mineralogical Features and REE Distribution in Ortho- and Clinopyroxenes of the HaH 317 Enstatite Chondrite Dhofar 311, 730 and 731: New Lunar Meteorites from Oman; The Deuterium Content of Individual Murchison Amino Acids; Clues to the Formation of PV1, an Enigmatic Carbon-rich Chondritic Clast from the Plainview H-Chondrite Regolith Breccia ;Numerical Simulations of the Production of Extinct Radionuclides and ProtoCAIs by Magnetic Flaring.

Evaluation of effects of super-heavy loading on the US 41 bridge over the White River : appendices.

DOT National Transportation Integrated Search

2011-01-01

Built in 1958, the US-41 White River Bridge is a two-girder, riveted steel structure located in Hazelton, IN. The bridge is comprised of two, sixteen span superstructures sharing a common substructure. Each superstructure also contains four pin and h...

Evaluation of effects of super-heavy loading on the US 41 bridge over the White River.

DOT National Transportation Integrated Search

2011-01-01

Built in 1958, the US-41 White River Bridge is a two-girder, riveted steel structure located in Hazelton, IN. The bridge is comprised of two, sixteen span : superstructures sharing a common substructure. Each superstructure also contains four pin and...

Syllable Structure in Arabic Varieties with a Focus on Superheavy Syllables

ERIC Educational Resources Information Center

Bamakhramah, Majdi A.

2010-01-01

This thesis has two broad goals. The first is to contribute to the study of Arabic phonology particularly syllable structure and syllabification. This will be achieved through examining phenomena related to syllable structure and syllabic weight such as syllabification, stress assignment, epenthesis, syncope, and sonority in three different…

Evaluation of effects of super-heavy loading on the US 41 bridge over the White River : technical summary.

DOT National Transportation Integrated Search

2011-01-01

Built in 1958, the US-41 White River Bridge is a two-girder, riveted steel structure located near Hazelton, IN. The bridge is comprised of two, sixteen span superstructures sharing a common substructure. Each superstructure also contains four pin and...

2010 Neutron Review: ORNL Neutron Sciences Progress Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bardoel, Agatha A; Counce, Deborah M; Ekkebus, Allen E

2011-06-01

During 2010, the Neutron Sciences Directorate focused on producing world-class science, while supporting the needs of the scientific community. As the instrument, sample environment, and data analysis tools at High Flux Isotope Reactor (HFIR ) and Spallation Neutron Source (SNS) have grown over the last year, so has promising neutron scattering research. This was an exciting year in science, technology, and operations. Some topics discussed are: (1) HFIR and SNS Experiments Take Gordon Battelle Awards for Scientific Discovery - Battelle Memorial Institute presented the inaugural Gordon Battelle Prizes for scientific discovery and technology impact in 2010. Battelle awards the prizesmore » to recognize the most significant advancements at national laboratories that it manages or co-manages. (2) Discovery of Element 117 - As part of an international team of scientists from Russia and the United States, HFIR staff played a pivotal role in the discovery by generating the berkelium used to produce the new element. A total of six atoms of ''ununseptium'' were detected in a two-year campaign employing HFIR and the Radiochemical Engineering Development Center at Oak Ridge National Laboratory (ORNL) and the heavy-ion accelerator capabilities at the Joint Institute for Nuclear Research in Dubna, Russia. The discovery of the new element expands the understanding of the properties of nuclei at extreme numbers of protons and neutrons. The production of a new element and observation of 11 new heaviest isotopes demonstrate the increased stability of super-heavy elements with increasing neutron numbers and provide the strongest evidence to date for the existence of an island of enhanced stability for super-heavy elements. (3) Studies of Iron-Based High-Temperature Superconductors - ORNL applied its distinctive capabilities in neutron scattering, chemistry, physics, and computation to detailed studies of the magnetic excitations of iron-based superconductors (iron pnictides and chalcogenides), a class of materials discovered in 2008. This research is yielding new insights into the relationship between magnetism and superconductivity and has established several key features of this family of high-temperature superconducting (HTS ) materials: the maximum magnetic field at which they can function, the nature of the electrons involved in the superconductivity, the dependence of the properties upon chemical substitution, and the character of the magnetic fluctuations in the material. The results suggest that despite important differences between these materials and the HTS copper oxides, a universal mechanism may be responsible for the unconventional superconductivity. (4) Coal Sequestration Research: A New Home for Greenhouse Gases - One possibility for slowing down the increasing levels of carbon dioxide (CO{sub 2}) in the atmosphere is to capture the gas in natural underground features such as coal seams. Critical to the feasibility of this technology is determining how much CO{sub 2} can be stored, no method for which has been found - until now. (5) Accelerator Reliability Passes 92% - In December 2010, SNS set a new record for itself when the accelerator ran at 1 MW with 100% reliability. Target Performance Exceeds All Expectations - The mercury target used at SNS is the first of its kind. During the design and planning for SNS, many people were skeptical that the target would work. In 2010, it was confirmed that the target was working not only well but much better than anyone would have imagined. (6) Changing the World of Data Acquisition - Researchers at SNS are starting to benefit from event-based data analysis. Event data mode captures and stores an individual data set for every single neutron that strikes a detector - precisely when and where the neutron is detected. This technique provides numerous advantages over traditional methods. Event data mode allows researchers to process their data at the highest resolution possible with no loss of data. This method of data collection provides a much more efficient way for users to gather data and get the most from their beam time. (7) New Laboratories for Users - The HFIR and SNS user communities continue to grow dramatically. In 2010, HFIR hosted 862 users and SNS 796, outpacing projections for both facilities. To meet the needs of those users, a new complex of 13 laboratories is now open for users at SNS. (8) Innovative Detectors Provide Relief from Helium-3 Shortage - Helium-3 ({sup 3}He) has been the gas of choice for gaseous detectors since the early days of neutron science. About two years ago, detector scientists worldwide faced the reality that stockpiles of {sup 3}He are dwindling rapidly, while demand for it has risen by a factor of five. The Neutron Sciences Detectors Group has developed two new types of detectors that don't rely on {sup 3}He: the Anger camera and the wavelength shifting fiber neutron detector, both of which use lithium ({sup 6}Li).« less

α decay and cluster radioactivity of nuclei of interest to the synthesis of Z =119 , 120 isotopes

NASA Astrophysics Data System (ADS)

Poenaru, D. N.; Gherghescu, R. A.

2018-04-01

Super-heavy nuclei of interest for the forthcoming synthesis of the isotopes with Z =119 , 120 are investigated. One of the very interesting latest experiments was performed at the velocity filter SHIP (GSI Darmstadt) trying to produce 299120 in a fusion reaction 248Cm(54Cr,3 n )299120 . We report calculations of α -decay half-lives using four models: AKRA (Akrawy), ASAF (analytical superasymmetric fission), UNIV (universal formula), and semFIS (semi-empirical formula based on fission theory). The released energy, Q , is calculated using the theoretical model of atomic masses, WS4. For Sr,9492 cluster radioactivity of 120,302300 we predict a branching ratio relative to α decay of -0.10 and 0.49, respectively, meaning that it is worth trying to detect such kinds of decay modes in competition with α decay.

Stability of superheavy nuclei

NASA Astrophysics Data System (ADS)

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.

Central depression in nucleonic densities: Trend analysis in the nuclear density functional theory approach

NASA Astrophysics Data System (ADS)

Schuetrumpf, B.; Nazarewicz, W.; Reinhard, P.-G.

2017-08-01

Background: The central depression of nucleonic density, i.e., a reduction of density in the nuclear interior, has been attributed to many factors. For instance, bubble structures in superheavy nuclei are believed to be due to the electrostatic repulsion. In light nuclei, the mechanism behind the density reduction in the interior has been discussed in terms of shell effects associated with occupations of s orbits. Purpose: The main objective of this work is to reveal mechanisms behind the formation of central depression in nucleonic densities in light and heavy nuclei. To this end, we introduce several measures of the internal nucleonic density. Through the statistical analysis, we study the information content of these measures with respect to nuclear matter properties. Method: We apply nuclear density functional theory with Skyrme functionals. Using the statistical tools of linear least square regression, we inspect correlations between various measures of central depression and model parameters, including nuclear matter properties. We study bivariate correlations with selected quantities as well as multiple correlations with groups of parameters. Detailed correlation analysis is carried out for 34Si for which a bubble structure has been reported recently, 48Ca, and N =82 , 126, and 184 isotonic chains. Results: We show that the central depression in medium-mass nuclei is very sensitive to shell effects, whereas for superheavy systems it is firmly driven by the electrostatic repulsion. An appreciable semibubble structure in proton density is predicted for 294Og, which is currently the heaviest nucleus known experimentally. Conclusion: Our correlation analysis reveals that the central density indicators in nuclei below 208Pb carry little information on parameters of nuclear matter; they are predominantly driven by shell structure. On the other hand, in the superheavy nuclei there exists a clear relationship between the central nucleonic density and symmetry energy.

Reflections

NASA Astrophysics Data System (ADS)

Greiner, Walter

2012-01-01

This symposium was very special. It was topical: Some of the most outstanding problems in Nuclear Physics were discussed: Superheavy elements; extremely neutron rich elements, as well as nuclei with strangeness and their possible creation in the cosmos and on earth; the nuclear equation of state has to be identified within strongly compressed and hot nuclear matter as it appears in nucleus-nucleus encounters; giant nuclear systems which are short lived (˜ 10-19 - 10-20 seconds) and extremely important for identifying the vacuum decay in overcritical electric fields (this is a very fundamental process - the most fundamental one in Quantum Electrodynamics!); astrophysical centers of extreme high density around which magnificent sun-like objects are Kepler-orbiting are discovered in our Galaxy by R. Genzel and colleagues (these centers are no black holes those don't exist at all because repulsive gravitational forces may play an important role - the pseudocomplex general relativity eliminates the Schwarzschild singularity); network physics for distributing energy (nuclear, wind, sun, tides,...) all over Europe (and over the world) is basic for energy consumption now and even more so in future. We heard wonderful talks and I am grateful to all the friends and speakers (from Russia, America, Europe and India) for coming to Goa. It was a great symposium! Particular thanks go to Professor Bikash Sinha and especially to Professor Debades Bandyopadhyay from Calcutta who had the idea for and organized this Goa-symposium....

The Role of the Syllable in the Segmentation of Cairene Spoken Arabic

ERIC Educational Resources Information Center

Aquil, Rajaa

2012-01-01

The syllable as a perceptual unit has been investigated cross linguistically. In Cairene Arabic syllables fall into three categories, light CV, heavy CVC/CVV and superheavy CVCC/CVVC. However, heavy syllables in Cariene Arabic have varied weight depending on their position in a word, whether internal or final. The present paper investigates the…

Peculiarities of the electron energy spectrum in the Coulomb field of a superheavy nucleus

NASA Astrophysics Data System (ADS)

Voronov, B. L.; Gitman, D. M.; Levin, A. D.; Ferreira, R.

2016-05-01

We consider the peculiarities of the electron energy spectrum in the Coulomb field of a superheavy nucleus and discuss the long history of an incorrect interpretation of this problem in the case of a pointlike nucleus and its current correct solution. We consider the spectral problem in the case of a regularized Coulomb potential. For some special regularizations, we derive an exact equation for the point spectrum in the energy interval (-m,m) and find some of its solutions numerically. We also derive an exact equation for charges yielding bound states with the energy E = -m; some call them supercritical charges. We show the existence of an infinite number of such charges. Their existence does not mean that the oneparticle relativistic quantum mechanics based on the Dirac Hamiltonian with the Coulomb field of such charges is mathematically inconsistent, although it is physically unacceptable because the spectrum of the Hamiltonian is unbounded from below. The question of constructing a consistent nonperturbative second-quantized theory remains open, and the consequences of the existence of supercritical charges from the standpoint of the possibility of constructing such a theory also remain unclear.

Decay of super-heavy particles: user guide of the SHdecay program

NASA Astrophysics Data System (ADS)

Barbot, C.

2004-02-01

I give here a detailed user guide for the C++ program SHdecay, which has been developed for computing the final spectra of stable particles (protons, photons, LSPs, electrons, neutrinos of the three species and their antiparticles) arising from the decay of a super-heavy X particle. It allows to compute in great detail the complete decay cascade for any given decay mode into particles of the Minimal Supersymmetric Standard Model (MSSM). In particular, it takes into account all interactions of the MSSM during the perturbative cascade (including not only QCD, but also the electroweak and 3rd generation Yukawa interactions), and includes a detailed treatment of the SUSY decay cascade (for a given set of parameters) and of the non-perturbative hadronization process. All these features allow us to ensure energy conservation over the whole cascade up to a numerical accuracy of a few per mille. Yet, this program also allows to restrict the computation to QCD or SUSY-QCD frameworks. I detail the input and output files, describe the role of each part of the program, and include some advice for using it best. Program summaryTitle of program: SHdecay Catalogue identifier:ADSL Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSL Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer and operating system: Program tested on PC running Linux KDE and Suse 8.1 Programming language used: C with STL C++ library and using the standard gnu g++ compiler No. lines in distributed program: 14 955 No. of bytes in distributed program, including test data, etc.: 624 487 Distribution format: tar gzip file Keywords: Super-heavy particles, fragmentation functions, DGLAP equations, supersymmetry, MSSM, UHECR Nature of physical problem: Obtaining the energy spectra of the final stable decay products (protons, photons, electrons, the three species of neutrinos and the LSPs) of a decaying super-heavy X particle, within the framework of the Minimal Supersymmetric Standard Model (MSSM). It can be done numerically by solving the full set of DGLAP equations in the MSSM for the perturbative evolution of the fragmentation functions Dp2p1( x, Q) of any particle p1 into any other p2 ( x is the energy fraction carried by the particle p2 and Q its virtuality), and by treating properly the different decay cascades of all unstable particles and the final hadronization of quarks and gluons. In order to obtain proper results at very low values of x (up to x˜10 -13), NLO color coherence effects have been included by using the Modified Leading Log Approximation (MLLA). Method of solution: the DGLAP equations are solved by a four order Runge-Kutta method with a fixed step. Typical running time: Around 35 hours for the first run, but the most time consuming sub-programs can be run only once for most applications.

Neutron-deficient superheavy nuclei obtained in the 240Pu+48Ca reaction

NASA Astrophysics Data System (ADS)

Utyonkov, V. K.; Brewer, N. T.; Oganessian, Yu. Ts.; Rykaczewski, K. P.; Abdullin, F. Sh.; Dmitriev, S. N.; Grzywacz, R. K.; Itkis, M. G.; Miernik, K.; Polyakov, A. N.; Roberto, J. B.; Sagaidak, R. N.; Shirokovsky, I. V.; Shumeiko, M. V.; Tsyganov, Yu. S.; Voinov, A. A.; Subbotin, V. G.; Sukhov, A. M.; Karpov, A. V.; Popeko, A. G.; Sabel'nikov, A. V.; Svirikhin, A. I.; Vostokin, G. K.; Hamilton, J. H.; Kovrizhnykh, N. D.; Schlattauer, L.; Stoyer, M. A.; Gan, Z.; Huang, W. X.; Ma, L.

2018-01-01

We present new results from investigations of the 240Pu+48Ca reaction at a projectile energy of 250 MeV. Three new decay chains of 285Fl were detected with decay properties mostly consistent with those measured in earlier studies. An additional chain was observed where the nuclei may decay through energy levels different from those of the other six chains registered so far. The cross section of the 240Pu(48Ca,3 n )285Fl reaction was measured to be 0 .58-0.33+0.60pb , which is a factor of about 4-5 lower than that measured in the previous experiment at 245 MeV beam energy [V. K. Utyonkov et al., Phys. Rev. C 92, 034609 (2015)., 10.1103/PhysRevC.92.034609], consistent with expectations. The origin of an additional chain consisting of a recoil, α particle, and fission event is analyzed. The assignment of 25 short-lived SF events observed in this experiment is also discussed.

Hyperheavy nuclei in covariant density functional theory: the existence and stability

NASA Astrophysics Data System (ADS)

Gyawali, Abhinaya; Agbemava, Sylvester; Afanasjev, Anatoli

2017-09-01

The limits of existence of finite nuclei is one of interesting questions of modern low-energy nuclear physics. A lot of theoretical efforts have been dedicated to the study of superheavy nuclei with Z < 126. However, very little is known about existence and stability of hyperheavy nuclei with proton numbers Z > 126 . Almost all investigations of such nuclei consider only spherical shapes for the ground states. However, the study of superheavy nuclei indicates that such assumption leads in many cases to misinterpretation of the situation. Thus, we performed a systematic investigation of such nuclei for proton numbers from 122 up to 184 and from two-proton drip line up to two-neutron one within the axial relativistic Hartree-Bogoliubov theory. The calculations are carried out in large deformation space extending from megadeformed oblate shapes via spherical ones up to scission configuration. The stability of such nuclei against fission (including triaxial and octupole shapes) and beta-decays have been investigated and the islands of their stability have been defined. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Award No. DE-SC0013037 and by Department of Energy, National Nuclear Security Administration under Award Number DE-NA0002925.

Fusion-fission and quasifission of superheavy systems with Z =110 -116 formed in 48Ca-induced reactions

NASA Astrophysics Data System (ADS)

Kozulin, E. M.; Knyazheva, G. N.; Itkis, I. M.; Itkis, M. G.; Bogachev, A. A.; Chernysheva, E. V.; Krupa, L.; Hanappe, F.; Dorvaux, O.; Stuttgé, L.; Trzaska, W. H.; Schmitt, C.; Chubarian, G.

2014-11-01

Background: In heavy-ion-induced reactions the mechanism leading to the formation of the compound nucleus and the role of quasifission is still not clear. Purpose: Investigation of the quasifission process of superheavy composite systems with Z =110 -116 and comparison with properties of fusion-fission and quasifission of lighter composite systems. Method: Mass and energy distributions of fissionlike fragments formed in the reactions 48Ca+232Th, 238U , 244Pu , and 248Cm at energies near the Coulomb barrier have been measured using the double-arm time-of-flight spectrometer CORSET at the U-400 cyclotron of the FLNR JINR. Results: The most probable fragment masses as well as total kinetic energies and their dispersions in dependence on the interaction energies and ion-target combinations have been studied for asymmetric and symmetric fragments formed in the reactions. The capture cross sections were obtained for the reactions 48Ca+244Pu and 248Cm . The lower limits for fission barriers of 283 -286Cn , 289 -292Fl , and 293 -296Lv compound nuclei were estimated. Conclusions: Analysis of the properties of symmetric fragments has shown that a significant part of these fragments may be attributed to fusion-fission process for the reactions 48Ca +238U , 244Pu , and 248Cm .

Density-dependent covariant energy density functionals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lalazissis, G. A.

2012-10-20

Relativistic nuclear energy density functionals are applied to the description of a variety of nuclear structure phenomena at and away fromstability line. Isoscalar monopole, isovector dipole and isoscalar quadrupole giant resonances are calculated using fully self-consistent relativistic quasiparticle randomphase approximation, based on the relativistic Hartree-Bogoliubovmodel. The impact of pairing correlations on the fission barriers in heavy and superheavy nuclei is examined. The role of pion in constructing desnity functionals is also investigated.

Spontaneous fission of the end product in α-decay chain of recoiled superheavy nucleus: A theoretical study

NASA Astrophysics Data System (ADS)

Kaur, Amandeep; Sawhney, Gudveen; Sharma, Manoj K.; Gupta, Raj K.

The temperature-dependent preformed cluster model [PCM(T)] is employed to extend our recent work [Niyti, G. Sawhney, M. K. Sharma and R. K. Gupta, Phys. Rev. C 91 (2015) 054606] on α-decay chains of various isotopes of Z = 113-118 superheavy nuclei (SHN), to spontaneous fissioning nuclei 103266Lr, 104267Rf, 105266‑268Db, 111281Rg, and 112282Cn occurring as end products of these α-decay chains. The behavior of fragment mass distribution and competitive emergence of the dominant decay mode, i.e., the α-emission versus spontaneous fission (SF), are studied for identifying the most probable heavy fission fragments, along with the estimation of SF half-life times T1/2SF and total kinetic energy (TKE) of the above noted isotopes of Z = 103-112 nuclei decaying via the SF process. The mass distributions of chosen nuclei are clearly symmetric, independent of mass and temperature. The most preferred decay fragment is found to lie in the neighborhood of doubly magic shell closures of Z = 50 and N = 82, with largest preformation factor P0. In addition, a comparative study of the “hot compact” and “cold elongated” configurations of β2i-deformed and 𝜃iopt-oriented nuclei indicates significantly different behaviors of the two mass fragmentation yields, favoring “hot compact” configuration.

A new beam diagnostic system for the MASHA setup

NASA Astrophysics Data System (ADS)

Motycak, S.; Rodin, A. M.; Novoselov, A. S.; Podshibyakin, A. V.; Krupa, L.; Belozerov, A. V.; Vedeneyev, V. Yu.; Gulyaev, A. V.; Gulyaeva, A. V.; Kliman, J.; Salamatin, V. S.; Stepantsov, S. V.; Chernysheva, E. V.; Yuchimchuk, S. A.; Komarov, A. B.; Kamas, D.

2016-09-01

A new beam diagnostic system based on the PXI standard was developed, tested, and used in the MASHA setup experiment. The beam energy and beam current measurements were carried out using several methods. The online time-of-flight energy measurements were carried out using three pick-up detectors. We used two electronic systems to measure the time between the pick-ups. The first system was based on fast Agilent digitizers (2-channel, 4-GHz sampling rate), and the second one was based on a constant fraction discriminator (CFD) connected to a time-to-digital converter (TDC, 5-ps resolution). A new graphical interface to monitor the electronic devices and to perform the online calculations of energy was developed using MFC C++. The second system based on microchannel plate (time-of-flight) and silicon detectors for the determination of beam energy and the type of accelerated particles was also used. The beam current measurements were carried out with two different sensors. The first sensor is a rotating Faraday cup placed in front of the target, and the second one is an emission detector installed at the rear of the target. This system is now used in experiments for the synthesis of superheavy elements at the U400M cyclotron of the Flerov Laboratory of Nuclear Reactions (FLNR).

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

NASA Astrophysics Data System (ADS)

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 suppressed by these two quasifission processes, since the sub-barrier heavy element yield is likely to be determined by the product of the probabilities of surviving each quasifission process.

Upper limit on magnetic monopole flux from Baksan experiment

NASA Technical Reports Server (NTRS)

Alexeyev, E. N.; Boliev, M. M.; Chudakov, A. E.; Mikheyev, S. P.

1985-01-01

No indication of slowly moving penetrating particles in cosmic radiation underground was found during two years observation. Particle velocity and pulse shape are main criteria for search. Probability of the imitation of slow particles (Beta 0.1) by atmospheric muons is negligible. Our upper limit on superheavy magnetic monopole flux is now 1.86 x 10 to the minus 15th power cm(-2) sr(-1) s(-1) (90% c.l.) for velocity range 2 x 0.0001 beta 0.1.

Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling

PubMed Central

Tokiwa, Yoshifumi; Piening, Boy; Jeevan, Hirale S.; Bud’ko, Sergey L.; Canfield, Paul C.; Gegenwart, Philipp

2016-01-01

Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with 3He gas are widely used for cooling below 1 K. However, usage of the gas has been increasingly difficult because of the current worldwide shortage. Therefore, it is important to consider alternative methods of refrigeration. We show that a new type of refrigerant, the super-heavy electron metal YbCo2Zn20, can be used for adiabatic demagnetization refrigeration, which does not require 3He gas. This method has a number of advantages, including much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb1−xScxCo2Zn20 by partial Sc substitution, with x ~ 0.19. The substitution induces chemical pressure that drives the materials to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures, enabling final temperatures well below 100 mK. This performance has, up to now, been restricted to insulators. For nearly a century, the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. This study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration. PMID:27626073

Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling

DOE PAGES

Tokiwa, Yoshifumi; Piening, Boy; Jeevan, Hirale S.; ...

2016-09-09

Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with 3He gas are widely used for cooling below 1 Kelvin. However, usage of the gas has been increasingly difficult because of the current world-wide shortage. Therefore, it is important to consider alternative methods of refrigeration. We show that a new type of refrigerant, the super-heavy electron metal YbCo 2Zn 20, can be used for adiabatic demagnetization refrigeration, which does not requiremore » 3He gas. This method has a number of advantages, including much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb 1$-$xSc xCo 2Zn 20 by partial Sc substitution, with x ~ 0.19. The substitution induces chemical pressure that drives the materials to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures, enabling final temperatures well below 100 mK. This performance has, up to now, been restricted to insulators. For nearly a century, the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. Lastly, this study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration.« less

Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling.

PubMed

Tokiwa, Yoshifumi; Piening, Boy; Jeevan, Hirale S; Bud'ko, Sergey L; Canfield, Paul C; Gegenwart, Philipp

2016-09-01

Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with (3)He gas are widely used for cooling below 1 K. However, usage of the gas has been increasingly difficult because of the current worldwide shortage. Therefore, it is important to consider alternative methods of refrigeration. We show that a new type of refrigerant, the super-heavy electron metal YbCo2Zn20, can be used for adiabatic demagnetization refrigeration, which does not require (3)He gas. This method has a number of advantages, including much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb1-x Sc x Co2Zn20 by partial Sc substitution, with x ~ 0.19. The substitution induces chemical pressure that drives the materials to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures, enabling final temperatures well below 100 mK. This performance has, up to now, been restricted to insulators. For nearly a century, the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. This study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration.

Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tokiwa, Yoshifumi; Piening, Boy; Jeevan, Hirale S.

Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with 3He gas are widely used for cooling below 1 Kelvin. However, usage of the gas has been increasingly difficult because of the current world-wide shortage. Therefore, it is important to consider alternative methods of refrigeration. We show that a new type of refrigerant, the super-heavy electron metal YbCo 2Zn 20, can be used for adiabatic demagnetization refrigeration, which does not requiremore » 3He gas. This method has a number of advantages, including much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb 1$-$xSc xCo 2Zn 20 by partial Sc substitution, with x ~ 0.19. The substitution induces chemical pressure that drives the materials to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures, enabling final temperatures well below 100 mK. This performance has, up to now, been restricted to insulators. For nearly a century, the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. Lastly, this study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration.« less

Toroidal high-spin isomers in the nucleus 304120

NASA Astrophysics Data System (ADS)

Staszczak, A.; Wong, Cheuk-Yin; Kosior, A.

2017-05-01

Background: Strongly deformed oblate superheavy nuclei form an intriguing region where the toroidal nuclear structures may bifurcate from the oblate spheroidal shape. The bifurcation may be facilitated when the nucleus is endowed with a large angular moment about the symmetry axis with I =Iz . The toroidal high-K isomeric states at their local energy minima can be theoretically predicted using the cranked self-consistent Skyrme-Hartree-Fock method. Purpose: We use the cranked Skyrme-Hartree-Fock method to predict the properties of the toroidal high-spin isomers in the superheavy nucleus 120304184. Method: Our method consists of three steps: First, we use the deformation-constrained Skyrme-Hartree-Fock-Bogoliubov approach to search for the nuclear density distributions with toroidal shapes. Next, using these toroidal distributions as starting configurations, we apply an additional cranking constraint of a large angular momentum I =Iz about the symmetry z axis and search for the energy minima of the system as a function of the deformation. In the last step, if a local energy minimum with I =Iz is found, we perform at this point the cranked symmetry- and deformation-unconstrained Skyrme-Hartree-Fock calculations to locate a stable toroidal high-spin isomeric state in free convergence. Results: We have theoretically located two toroidal high-spin isomeric states of 120304184 with an angular momentum I =Iz=81 ℏ (proton 2p-2h, neutron 4p-4h excitation) and I =Iz=208 ℏ (proton 5p-5h, neutron 8p-8h) at the quadrupole moment deformations Q20=-297.7 b and Q20=-300.8 b with energies 79.2 and 101.6 MeV above the spherical ground state, respectively. The nuclear density distributions of the toroidal high-spin isomers 120304184(Iz=81 ℏ and 208 ℏ ) have the maximum density close to the nuclear matter density, 0.16 fm-3, and a torus major to minor radius aspect ratio R /d =3.25 . Conclusions: We demonstrate that aligned angular momenta of Iz=81 ℏ and 208 ℏ arising from multiparticle-multihole excitations in the toroidal system of 120304184 can lead to high-spin isomeric states, even though the toroidal shape of 120304184 without spin is unstable. Toroidal energy minima without spin may be possible for superheavy nuclei with higher atomic numbers, Z ≳122 , as reported previously [7 A. Staszczak and C. Y. Wong, Acta Phys. Pol. B 40, 753 (2008)].

Toroidal high-spin isomers in the nucleus 120 304

DOE PAGES

Staszczak, A.; Wong, Cheuk-Yin; Kosior, A.

2017-05-22

Strongly deformed oblate superheavy nuclei form an intriguing region where the toroidal nuclear structures may bifurcate from the oblate spheroidal shape. The bifurcation may be facilitated when the nucleus is endowed with a large angular moment about the symmetry axis withmore » $$I=I_{z}$$. The toroidal high-$K$ isomeric states at their local energy minima can be theoretically predicted using the cranked self-consistent Skyrme-Hartree-Fock method. We use the cranked Skyrme-Hartree-Fock method to predict the properties of the toroidal high-spin isomers in the superheavy nucleus $$^{304}{120}_{184}$$. This method consists of three steps: first, we use the deformation-constrained Skyrme-Hartree-Fock-Bogoliubov approach to search for the nuclear density distributions with toroidal shapes. Next, using these toroidal distributions as starting configurations we apply an additional cranking constraint of a large angular momentum $$I=I_{z}$$ about the symmetry $z$-axis and search for the energy minima of the system as a function of the deformation. In the last step, if a local energy minimum with $$I=I_{z}$$ is found, we perform at this point the cranked symmetry- and deformation-unconstrained Skyrme-Hartree-Fock calculations to locate a stable toroidal high-spin isomeric state in free convergence. Furthemore, we have theoretically located two toroidal high-spin isomeric states of $$^{304}{120}_{184}$$ with an angular momentum $I$=$$I_z$$=81$$\\hbar$$ (proton 2p-2h, neutron 4p-4h excitation) and $I$=$$I_z$$=208$$\\hbar$$ (proton 5p-5h, neutron 8p-8h) at the quadrupole moment deformations $$Q_{20}=-297.7$$~b and $$Q_{20}=-300.8$$~b with energies 79.2 MeV and 101.6 MeV above the spherical ground state, respectively. The nuclear density distributions of the toroidal high-spin isomers $$^{304}{120}_{184}(I_z$$=81$$\\hbar$$ and 208$$\\hbar$$) have the maximum density close to the nuclear matter density, 0.16 fm$$^{-3}$$, and a torus major to minor radius aspect ratio $R/d=3.25$. Here, we demonstrate that aligned angular momenta of $$I_z$$=81$$\\hbar$$ and 208$$\\hbar$$ arising from multi-particle-multi-hole excitations in the toroidal system of $$^{304}{120}_{184}$$ can lead to high-spin isomeric states, even though the toroidal shape of $$^{304}120_{184}$$ without spin is unstable. Toroidal energy minima without spin may be possible for superheavy nuclei with higher atomic numbers, $$Z\\gtrsim$$122, as reported previously [A. Staszczak and C. Y. Wong,Acta Phys. Pol. B 40 , 753 (2008)].« less

A Study of Heavy Trans-Iron Primary Cosmic Rays (Z More than or Equal to 55) with a Fast Film Cerenkov Detector. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Pinsky, L. S.

1972-01-01

The detection and measurement of the cosmic ray charge spectrum for nuclei heavier than iron (Fe, Z = 26) are discussed. These trans-iron nuclei are of great interest for several reasons. They promise to be one of the more sensitive clocks for use in determining the age of cosmic rays. The discovery of radioactive nuclides and their decay products in the primary flux, will allow an estimation of the elapsed time since these cosmic rays were synthesized. In addition, the relatively short interaction length of the very heavy trans-iron particles makes their relative abundance a source of information regarding the amount of interstellar matter that they had to traverse to reach the earth. A study of the trans-iron cosmic rays may provide clues as to the very processes of nucleosyntheses by which the bulk of the trans-iron nuclei in the universe are produced. This in turn may shed light on the mechanics of the supernova, which is postulated to be the major source of all cosmic rays. Finally, trans-iron cosmic ray experiments may demonstrate the existence of the recently postulated super-heavy nuclei.

KEWPIE: A dynamical cascade code for decaying exited compound nuclei

NASA Astrophysics Data System (ADS)

Bouriquet, Bertrand; Abe, Yasuhisa; Boilley, David

2004-05-01

A new dynamical cascade code for decaying hot nuclei is proposed and specially adapted to the synthesis of super-heavy nuclei. For such a case, the interesting channel is of the tiny fraction that will decay through particles emission, thus the code avoids classical Monte-Carlo methods and proposes a new numerical scheme. The time dependence is explicitely taken into account in order to cope with the fact that fission decay rate might not be constant. The code allows to evaluate both statistical and dynamical observables. Results are successfully compared to experimental data.

Fission and quasifission of composite systems with Z =108 -120 : Transition from heavy-ion reactions involving S and Ca to Ti and Ni ions

NASA Astrophysics Data System (ADS)

Kozulin, E. M.; Knyazheva, G. N.; Novikov, K. V.; Itkis, I. M.; Itkis, M. G.; Dmitriev, S. N.; Oganessian, Yu. Ts.; Bogachev, A. A.; Kozulina, N. I.; Harca, I.; Trzaska, W. H.; Ghosh, T. K.

2016-11-01

Background: Suppression of compound nucleus formation in the reactions with heavy ions by a quasifission process in dependence on the reaction entrance channel. Purpose: Investigation of fission and quasifission processes in the reactions 36S,48Ca,48Ti , and 64Ni+238U at energies around the Coulomb barrier. Methods: Mass-energy distributions of fissionlike fragments formed in the reaction 48Ti+238U at energies of 247, 258, and 271 MeV have been measured using the double-arm time-of-flight spectrometer CORSET at the U400 cyclotron of the Flerov Laboratory of Nuclear Reactions and compared with mass-energy distributions for the reactions 36S,48Ca,64Ni+238U . Results: The most probable fragment masses as well as total kinetic energies and their dispersions in dependence on the interaction energies have been investigated for asymmetric and symmetric fragments for the studied reactions. The fusion probabilities have been deduced from the analysis of mass-energy distributions. Conclusion: The estimated fusion probability for the reactions S, Ca, Ti, and Ni ions with actinide nuclei shows that it depends exponentially on the mean fissility parameter of the system. For the reactions with actinide nuclei leading to the formation of superheavy elements the fusion probabilities are of several orders of magnitude higher than in the case of cold fusion reactions.

Fission and Properties of Neutron-Rich Nuclei

NASA Astrophysics Data System (ADS)

Hamilton, Joseph H.; Ramayya, A. V.; Carter, H. K.

2008-08-01

Opening session. Nuclear processes in stellar explosions / M. Wiescher. In-beam [symbol]-ray spectroscopy of neutron-rich nuclei at NSCL / A. Gade -- Nuclear structure I. Shell-model structure of neutron-rich nuclei beyond [symbol]Sn / A. Covello ... [et al.]. Shell structure and evolution of collectivity in nuclei above the [symbol]Sn core / S. Sarkar and M. S. Sarkar. Heavy-ion fusion using density-constrained TDHF / A. S. Umar and V. E. Oberacker. Towards an extended microscopic theory for upper-fp shell nuclei / K. P. Drumev. Properties of the Zr and Pb isotopes near the drip-line / V. N. Tarasov ... [et al.]. Identification of high spin states in [symbol] Cs nuclei and shell model calculations / K. Li ... [et al.]. Recent measurements of spherical and deformed isomers using the Lohengrin fission-fragment spectrometer / G. S. Simpson ... [et al.] -- Nuclear structure II. Nuclear structure investigation with rare isotope spectroscopic investigations at GSI / P. Boutachkov. Exploring the evolution of the shell structures by means of deep inelastic reactions / G. de Anaelis. Probing shell closures in neutron-rich nuclei / R. Krücken for the S277 and REX-ISOLDEMINIBALL collaborations. Structure of Fe isotopes at the limits of the pf-shell / N. Hoteling ... [et al.]. Spectroscopy of K isomers in shell-stabilized trans-fermium nuclei / S. K. Tandel ... [et al.] -- Radioactive ion beam facilities. SPIRAL2 at GANIL: a world leading ISOL facility for the next decade / S. Gales. New physics at the International Facility for Antiproton and Ion Research (FAIR) next to GSI / I. Augustin ... [et al.]. Radioactive beams from a high powered ISOL system / A. C. Shotter. RlKEN RT beam factory / T. Motobayashi. NSCL - ongoing activities and future perspectives / C. K. Gelbke. Rare isotope beams at Argonne / W. F. Henning. HRIBF: scientific highlights and future prospects / J. R. Beene. Radioactive ion beam research done in Dubna / G. M. Ter-Akopian ... [et al.] -- Fission I. Fission-fragment spectroscopy with STEFF / A. G. Smith ... [et al.]. Gamma ray multiplicity of [symbol]Cf spontaneous fission using LiBerACE / D. L. Bleuel ... [et al.]. Excitation energy dependence of fragment mass and total kinetic energy distributions in proton-induced fission of light actinides / I. Nishinaka ... [et al.]. A dynamical calculation of multi-modal nuclear fission / T. Wada and T. Asano. Structure of fission potential energy surfaces in ten-dimensional spaces / V. V. Pashkevich, Y. K Pyatkov and A. V. Unzhakova. A possible enhancement of nuclear fission in scattering with low energy charged particles / V. Gudkov. Dynamical multi-break processes in the [symbol]Sn + [symbol]Ni system at 35 MeV/Nucleon / M. Papa and ISOSPIN-RE VERSE collaboration -- New experimental techniques. MTOF - a high resolution isobar separator for studies of exotic decays / A. Piechaczek ... [et al.]. Development of ORRUBA: a silicon array for the measurement of transfer reactions in inverse kinematics / S. D. Pain ... [et al.]. Indian national gamma array: present & future / R. K. Bhowmik. Absolute intensities of [symbol] rays emitted in the decay of [symbol]U / H. C. Griffin -- Superheavy elements theory and experiments / M. G. Itkis ... [et al.]. Study of superheavy elements at SHIP / S. Hofinann. Heaviest nuclei from [symbol]Ca-induced reactions / Yu. Ts. Oaanessian. Superheavy nuclei and giant nuclear systems / W. Greiner and V. Zagrebaev. Fission approach to alpha-decay of superheavy nuclei / D.N. Poenaru and W. Greiner. Superheavy elements in the Magic Islands / C. Samanta. Relativistic mean field studies of superheavy nuclei / A. V. Afanas jev. Understanding the synthesis of the heaviest nuclei / W. Loveland -- Mass measurements and g-factors. G factor measurements in neutron-rich [symbol]Cf fission fragments, measured using the gammasphere array / R. Orlandi ... [et al.]. Technique for measuring angular correlations and g-factors in neutron rich nuclei produced by the spontaneous fission of [symbol]Cf / A. V. Daniel ... [et al.]. Magnetic moment measurements in a radioactive beam environment / N. Benczer-Koller and G. Kumbartzki. g-Factor measurements of picosecond states: opportunities and limitations of the recoil-in-vacuum method / N. J. Stone ... [et al.]. Precision mass measurements and trap-assisted spectroscopy of fission products from Ni to Pd / A. Jokinen -- Fission II. Fission research at IRMM / F.-J. Hambsch. Fission yield measurements at the IGISOL facility with JYFLTRAP / H. Penttilä ... [et al.]. Fission of radioactive beams and dissipation in nuclear matter / A. Heinz (for the CHARMS collaboration). Fission of [symbol]U at 80 MeVlu and search for new neutron-rich isotopes / C.M. Folden, III ... [et al.]. Measurement of the average energy and multiplicity of prompt-fission neutrons and gamma rays from [symbol], [symbol], and [symbol] for incident neutron energies of 1 to 200 MeV / R. C. Haight ... [et al.]. Fission measurements with DANCE / M. Jandel ... [et al.]. Measured and calculated neutron-induced fission cross sections of [symbol]Pu / F. Tovesson and T. S. Hill. The fission barrier landscape / L. Phair and L. G. Moretto. Fast neutron-induced fission of some actinides and sub-actinides / A. B. Lautev ... [et al.] -- Fission III/Nuclear structure III. Complex structure in even-odd staggering of fission fragment yields / M. Caamāno and F. Rejmund. The surrogate method: past, present and future / S. R. Lesher ... [et al]. Effects of nuclear incompressibility on heavy-ion fusion / H. Esbensen and Ş. Mişicu. High spin states in [symbol]Pm / A. Dhal ... [et al]. Structure of [symbol]Sm, spherical vibrator versus softly deformed rotor / J. B. Gupta -- Astrophysics. Measuring the astrophysical S-factor in plasmas / A. Bonasera ... [et al.]. Is there shell quenching or shape coexistence in Cd isotopes near N = 82? / J. K. Hwang, A. V. Ramayya and J. H. Hamilton. Spectroscopy of neutron-rich palladium and cadmium isostopes near A= 120 / M. A. Stoyer and W. B. Walters -- Nuclear structure IV. First observation of new neutron-rich magnesium, aluminum and silicon isotopes / A. Stolz ... [et al.]. Spectroscopy of [symbol]Na revolution of shell structure with isospin / V. Tripathi ... [et al.]. Rearrangement of proton single particle orbitals in neutron-rich potassium isotopes - spectroscopy of [symbol]K / W. Królas ... [et al.]. Laser spectroscopy and the nature of the shape transition at N [symbol] 60 / B. Cheal ... [et al.]. Study of nuclei near stability as fission fragments following heavy-ion reactions / N. Fotiadis. [symbol]C and [symbol]N: lifetime measurements of their first-excited states / M. Wiedeking ... [et al.] -- Nuclear astrophysics. Isomer spectroscopy near [symbol]Sn - first observation of excited states in [symbol]Cd / M. Pfitzner ... [et al.]. Nuclear masses and what they imply for the structures of neutron rich nuclei / A. Awahamian and A. Teymurazyan. Multiple nucleosynthesis processes in the early universe / F. Montes. Single-neutron structure of neutron-rich nuclei near N = 50 and N = 82 / J. A. Cizewski ... [et al.]. [symbol]Cadmium: ugly duckling or young swan / W. B. Walters ... [et al.] -- Nuclear structure V. Evidence for chiral doublet bands in [symbol]Ru / Y. X. Luo ... [et al.]. Unusual octupole shape deformation terms and K-mixing / J. O. Rasmussen ... [et al.]. Spin assignments, mixing ratios, and g-factors in neutron rich [symbol]Cf fission products / C. Goodin ... [et al.]. Level structures and double [symbol]-bands in [symbol]Mo, [symbol]Mo and [symbol]Ru / S. J. Zhu ... [et al.] -- Nuclear theory. Microscopic dynamics of shape coexistence phenomena around [symbol]Se and [symbol]Kr / N. Hinohara ... [et al.]. Nuclear structure, double beta decay and test of physics beyond the standard model / A. Faessler. Collective modes in elastic nuclear matter / Ş. Mişicu and S. Bastrukov. From N = Z to neutron rich: magnetic moments of Cu isotopes at and above the [symbol]Ni and [symbol]Ni double shell closures - what next? / N. J. Stone, J. R. Stone and U. Köster -- Nuclear structure VI. Decay studies of nuclei near [symbol]Ni / R. Grzywacz. Weakening of the [symbol]Ni core for Z > 28, N > 50? / J. A. Winger ... [et al.]. Coulomb excitation of the odd-A [symbol]Cu isotopes with MINIBALL and REX-ISOLDE / I. Stefanescu ... [et al.]. Neutron single particle states and isomers in odd mass nickel isotopes near [symbol]Ni / M. M. Raiabali ... [et al.]. [symbol] and [symbol]-delayed neutron decay studies of [symbol]Ch at the HRIBF / S. V. Ilvushkin ... [et al.] -- Posters. Properties of Fe, Ni and Zn isotope chains near the drip-line / V. N. Tarasov ... [et al.]. Probing nuclear structure of [symbol]Xe / J. B. Gupta. Shape coexistence in [symbol]Zr and large deformation in [symbol]Zr / J. K. Hwang ... [et al.]. Digital electronics and their application to beta decay spectroscopy / S. N. Liddick, S. Padgett and R. Grzywacz. Nuclear shape and structure in neutron-rich [symbol]Tc / Y. X. Luo ... [et al.]. Speeding up the r-process. Investigation of first forbidden [symbol] decays in N > 50 isotopes near [symbol]Ni / S. Padgett ... [et al.]. Yields of fission products from various actinide targets / E. H. Sveiewski ... [et al.].

A Study of Multi-Λ Hypernuclei Within Spherical Relativistic Mean-Field Approach

NASA Astrophysics Data System (ADS)

Rather, Asloob A.; Ikram, M.; Usmani, A. A.; Kumar, B.; Patra, S. K.

2017-12-01

This research article is a follow up of an earlier work by M. Ikram et al., reported in Int. J. Mod. Phys. E 25, 1650103 (2016) where we searched for Λ magic numbers in experimentally confirmed doubly magic nucleonic cores in light to heavy mass region (i.e., 16 O-208 P b) by injecting Λ's into them. In the present manuscript, working within the state of the art relativistic mean field theory with the inclusion of Λ N and ΛΛ interaction in addition to nucleon-meson NL 3∗ effective force, we extend the search of lambda magic numbers in multi- Λ hypernuclei using the predicted doubly magic nucleonic cores 292120, 304120, 360132, 370132, 336138, 396138 of the elusive superheavy mass regime. In analogy to well established signatures of magicity in conventional nuclear theory, the prediction of hypernuclear magicities is made on the basis of one-, two- Λ separation energy ( S Λ, S 2Λ) and two lambda shell gaps ( δ 2Λ) in multi- Λ hypernuclei. The calculations suggest that the Λ numbers 92, 106, 126, 138, 184, 198, 240, and 258 might be the Λ shell closures after introducing the Λ's in the elusive superheavy nucleonic cores. The appearance of new lambda shell closures apart from the nucleonic ones predicted by various relativistic and non-relativistic theoretical investigations can be attributed to the relatively weak strength of the spin-orbit coupling in hypernuclei compared to normal nuclei. Further, the predictions made in multi- Λ hypernuclei under study resembles closely the magic numbers in conventional nuclear theory suggested by various relativistic and non-relativistic theoretical models. Moreover, in support of the Λ shell closure, the investigation of Λ pairing energy and effective Λ pairing gap has been made. We noticed a very close agreement of the predicted Λ shell closures with the survey made on the pretext of S Λ, S 2Λ, and δ 2Λ except for the appearance of magic numbers corresponding to Λ = 156 which manifest in Λ effective pairing gap and pairing energy. Also, the lambda single-particle spectrum is analyzed to mark the energy shell gap for further strengthening the predictions made on the basis of separation energies and shell gaps. Lambda and nucleon spin-orbit interactions are analyzed to confirm the reduction in magnitude of Λ spin-orbit interaction compared to the nucleonic case, however the interaction profile is similar in both the cases. Lambda and nucleon density distributions have been investigated to reveal the impurity effect of Λ hyperons which make the depression of central density of the core of superheavy doubly magic nuclei. Lambda skin structure is also seen.

Spectral analysis method for detecting an element

DOEpatents

Blackwood, Larry G [Idaho Falls, ID; Edwards, Andrew J [Idaho Falls, ID; Jewell, James K [Idaho Falls, ID; Reber, Edward L [Idaho Falls, ID; Seabury, Edward H [Idaho Falls, ID

2008-02-12

A method for detecting an element is described and which includes the steps of providing a gamma-ray spectrum which has a region of interest which corresponds with a small amount of an element to be detected; providing nonparametric assumptions about a shape of the gamma-ray spectrum in the region of interest, and which would indicate the presence of the element to be detected; and applying a statistical test to the shape of the gamma-ray spectrum based upon the nonparametric assumptions to detect the small amount of the element to be detected.

46 CFR 108.413 - Fusible element fire detection system.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Fusible element fire detection system. 108.413 Section... UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems § 108.413 Fusible element fire detection system. (a) A fusible element fire detection system may be installed. (b) The arrangements for the system...

The AMS Measurements and Its Applications in Nuclear Physics at China Institute of Atomic Energy (CIAE)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang Shan; Shen Hongtao; He Ming

2010-05-12

Accelerator Mass Spectrometry (AMS), initiated in late 1970s at McMaster university based on the accelerator and detector technique, has long been applied in the studies on archaeology, geology, and cosmology, as a powerful tool for isotope dating. The advantages of AMS in the analysis of rare nuclides by direct counting of the atoms, small sample size and relatively free from the interferences of molecular ions have been well documented. This paper emphasizes that AMS can not only be used for archaeology, geology, environment, biology and so on, but also served as a unique tool for nuclear physics research. In thismore » paper, the determination of the half-lives of {sup 79}Se, the measurements of the cross-sections of {sup 93}Nb(n,2n){sup 92g}Nb and {sup 238}U(n,3n){sup 236}U reactions, the detection and determination of ultratrace impurities in neutrino detector materials, and the measurement of the fission product nuclide {sup 126}Sn, are to be introduced, as some of examples of AMS applications in nuclear research conducted in AMS lab of China Institute of Atomic Energy. Searching for superheavy nuclides by using AMS is being planned.« less

System and method for detecting components of a mixture including tooth elements for alignment

DOEpatents

Sommer, Gregory Jon; Schaff, Ulrich Y.

2016-11-22

Examples are described including assay platforms having tooth elements. An impinging element may sequentially engage tooth elements on the assay platform to sequentially align corresponding detection regions with a detection unit. In this manner, multiple measurements may be made of detection regions on the assay platform without necessarily requiring the starting and stopping of a motor.

Fusion and quasifission studies for the 40Ca+186W,192Os reactions

NASA Astrophysics Data System (ADS)

Prasad, E.; Hinde, D. J.; Williams, E.; Dasgupta, M.; Carter, I. P.; Cook, K. J.; Jeung, D. Y.; Luong, D. H.; Palshetkar, C. S.; Rafferty, D. C.; Ramachandran, K.; Simenel, C.; Wakhle, A.

2017-09-01

Background: All elements above atomic number 113 have been synthesized using hot fusion reactions with calcium beams on statically deformed actinide target nuclei. Quasifission and fusion-fission are the two major mechanisms responsible for the very low production cross sections of superheavy elements. Purpose: To achieve a quantitative measurement of capture and quasifission characteristics as a function of beam energy in reactions forming heavy compound systems using calcium beams as projectiles. Methods: Fission fragment mass-angle distributions were measured for the two reactions 40Ca+186W and 40C+192Os, populating 226Pu and 232Cm compound nuclei, respectively, using the Heavy Ion Accelerator Facility and CUBE spectrometer at the Australian National University. Mass ratio distributions, angular distributions, and total fission cross sections were obtained from the experimental data. Simulations to match the features of the experimental mass-angle distributions were performed using a classical phenomenological approach. Results: Both 40Ca+186W and 40C+192Os reactions show strong mass-angle correlations at all energies measured. A maximum fusion probability of 60 -70 % is estimated for the two reactions in the energy range of the present study. Coupled-channels calculations assuming standard Woods-Saxon potential parameters overpredict the capture cross sections. Large nuclear potential diffuseness parameters ˜1.5 fm are required to fit the total capture cross sections. The presence of a weak mass-asymmetric quasifission component attributed to the higher angular momentum events can be reproduced with a shorter average sticking time but longer mass-equilibration time constant. Conclusions: The deduced above-barrier capture cross sections suggest that the dissipative processes are already occurring outside the capture barrier. The mass-angle correlations indicate that a compact shape is not achieved for deformation aligned collisions with lower capture barriers. The average sticking time of fast quasifission events is 10-20 s.

Fission barriers at the end of the chart of the nuclides

NASA Astrophysics Data System (ADS)

Möller, Peter; Sierk, Arnold J.; Ichikawa, Takatoshi; Iwamoto, Akira; Mumpower, Matthew

2015-02-01

We present calculated fission-barrier heights for 5239 nuclides for all nuclei between the proton and neutron drip lines with 171 ≤A ≤330 . The barriers are calculated in the macroscopic-microscopic finite-range liquid-drop model with a 2002 set of macroscopic-model parameters. The saddle-point energies are determined from potential-energy surfaces based on more than 5 000 000 different shapes, defined by five deformation parameters in the three-quadratic-surface shape parametrization: elongation, neck diameter, left-fragment spheroidal deformation, right-fragment spheroidal deformation, and nascent-fragment mass asymmetry. The energy of the ground state is determined by calculating the lowest-energy configuration in both the Nilsson perturbed-spheroid (ɛ ) and the spherical-harmonic (β ) parametrizations, including axially asymmetric deformations. The lower of the two results (correcting for zero-point motion) is defined as the ground-state energy. The effect of axial asymmetry on the inner barrier peak is calculated in the (ɛ ,γ ) parametrization. We have earlier benchmarked our calculated barrier heights to experimentally extracted barrier parameters and found average agreement to about 1 MeV for known data across the nuclear chart. Here we do additional benchmarks and investigate the qualitative and, when possible, quantitative agreement and/or consistency with data on β -delayed fission, isotope generation along prompt-neutron-capture chains in nuclear-weapons tests, and superheavy-element stability. These studies all indicate that the model is realistic at considerable distances in Z and N from the region of nuclei where its parameters were determined.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Möller, Peter; Sierk, Arnold J.; Ichikawa, Takatoshi

We present calculated fission-barrier heights for 5239 nuclides for all nuclei between the proton and neutron drip lines with 171 ≤ A ≤ 330. The barriers are calculated in the macroscopic-microscopic finite-range liquid-drop (FRLDM) with a 2002 set of macroscopic-model parameters. The saddle-point energies are determined from potential-energy surfaces based on more than five million different shapes, defined by five deformation parameters in the three-quadratic-surface shape parametrization: elongation, neck diameter, left-fragment spheroidal deformation, right-fragment spheroidal deformation, and nascent-fragment mass asymmetry. The energy of the ground state is determined by calculating the lowest-energy configuration in both the Nilsson perturbed-spheroid (ϵ) andmore » the spherical-harmonic (β) parametrizations, including axially asymmetric deformations. The lower of the two results (correcting for zero-point motion) is defined as the ground-state energy. The effect of axial asymmetry on the inner barrier peak is calculated in the (ϵ,γ) parametrization. We have earlier benchmarked our calculated barrier heights to experimentally extracted barrier parameters and found average agreement to about one MeV for known data across the nuclear chart. Here we do additional benchmarks and investigate the qualitative and, when possible, quantitative agreement and/or consistency with data on β-delayed fission, isotope generation along prompt-neutron-capture chains in nuclear-weapons tests, and superheavy-element stability. In addition these studies all indicate that the model is realistic at considerable distances in Z and N from the region of nuclei where its parameters were determined.« less

Soft CP violation and the global matter-antimatter symmetry of the universe

NASA Technical Reports Server (NTRS)

Senjanovic, G.; Stecker, F. W.

1980-01-01

Scenarios for baryon production are considered within the context of SU(5) and SO(10) grand unified theories where CP violation arises spontaneously. The spontaneous CP symmetry breaking then results in a matter-antimatter domain structure in the universe. Two possible, distinct types of theories of soft CP violation are defined. In the first type the CP nonconservation originates only from the breaking of SU(2) sub L X U(1) symmetry, and in the second type, even at the unification temperature scale, CP violation can emerge as a result of symmetry breaking by the vacuum expectation values of the superheavy Higgs sector scalars.

Population and decay of a Kπ=8- two-quasineutron isomer in 244Pu

NASA Astrophysics Data System (ADS)

Hota, S. S.; Tandel, S. K.; Chowdhury, P.; Ahmad, I.; Carpenter, M. P.; Chiara, C. J.; Greene, J. P.; Hoffman, C. R.; Jackson, E. G.; Janssens, R. V. F.; Kay, B. P.; Khoo, T. L.; Kondev, F. G.; Lakshmi, S.; Lalkovski, S.; Lauritsen, T.; Lister, C. J.; McCutchan, E. A.; Moran, K.; Peterson, D.; Shirwadkar, U.; Seweryniak, D.; Stefanescu, I.; Toh, Y.; Zhu, S.

2016-08-01

The decay of a Kπ=8- isomer in 244Pu and the collective band structures populating the isomer were studied using deep inelastic excitations with 47Ti and 208Pb beams, respectively. Precise measurements of M 1 /E 2 branching ratios in the band confirm a 9 /2-[734] ν⊗7 /2+[624] ν configuration assignment for the isomer, validating the systematics of Kπ=8- , two-quasineutron isomers observed in even-Z , N =150 isotones. These isomers around the deformed shell gap at N =152 provide critical benchmarks for theoretical predictions of single-particle energies in this gateway region to superheavy nuclei.

MSW-resonant fermion mixing during reheating

NASA Astrophysics Data System (ADS)

Kanai, Tsuneto; Tsujikawa, Shinji

2003-10-01

We study the dynamics of reheating in which an inflaton field couples two flavor fermions through Yukawa-couplings. When two fermions have a mixing term with a constant coupling, we show that the Mikheyev-Smirnov-Wolfenstein (MSW)-type resonance emerges due to a time-dependent background in addition to the standard fermion creation via parametric resonance. This MSW resonance not only alters the number densities of fermions generated by a preheating process but also can lead to the larger energy transfer from the inflaton to fermions. Our mechanism can provide additional source terms for the creation of superheavy fermions which may be relevant for the leptogenesis scenario.

Thermal neutron detector and gamma-ray spectrometer utilizing a single material

DOEpatents

Stowe, Ashley; Burger, Arnold; Lukosi, Eric

2017-05-02

A combined thermal neutron detector and gamma-ray spectrometer system, including: a detection medium including a lithium chalcopyrite crystal operable for detecting thermal neutrons in a semiconductor mode and gamma-rays in a scintillator mode; and a photodetector coupled to the detection medium also operable for detecting the gamma rays. Optionally, the detection medium includes a .sup.6LiInSe.sub.2 crystal. Optionally, the detection medium comprises a compound formed by the process of: melting a Group III element; adding a Group I element to the melted Group III element at a rate that allows the Group I and Group III elements to react thereby providing a single phase I-III compound; and adding a Group VI element to the single phase I-III compound and heating; wherein the Group I element includes lithium.

Capacitively readout multi-element sensor array with common-mode cancellation

DOEpatents

Britton, Jr., Charles L.; Warmack, Robert J.; Bryan, William L.; Jones, Robert L.; Oden, Patrick Ian; Thundat, Thomas

2001-01-01

An improved multi-element apparatus for detecting the presence of at least one chemical, biological or physical component in a monitored area comprising an array or single set of the following elements: a capacitive transducer having at least one cantilever spring element secured thereto, the cantilever element having an area thereof coated with a chemical having an affinity for the component to be detected; a pick-up plate positioned adjacent to the cantilever element at a distance such that a capacitance between the cantilever element and the pick-up plate changes as the distance between the cantilever element and the pick-up plate varies, the change in capacitance being a measurable variation; a detection means for measuring the measurable variation in the capacitance between the cantilever element and the pick-up plate that forms a measurement channel signal; and at least one feedback cantilever spring element positioned apart from the coated cantilever element, the cantilever element substantially unaffected by the component being monitored and providing a reference channel signal to the detection means that achieves a common mode cancellation between the measurement channel signal and reference channel signal.

Temperature differential detection device

DOEpatents

Girling, P.M.

1986-04-22

A temperature differential detection device for detecting the temperature differential between predetermined portions of a container wall is disclosed as comprising a Wheatstone bridge circuit for detecting resistance imbalance with a first circuit branch having a first elongated wire element mounted in thermal contact with a predetermined portion of the container wall, a second circuit branch having a second elongated wire element mounted in thermal contact with a second predetermined portion of a container wall with the wire elements having a predetermined temperature-resistant coefficient, an indicator interconnected between the first and second branches remote from the container wall for detecting and indicating resistance imbalance between the first and second wire elements, and connector leads for electrically connecting the wire elements to the remote indicator in order to maintain the respective resistance value relationship between the first and second wire elements. The indicator is calibrated to indicate the detected resistance imbalance in terms of a temperature differential between the first and second wall portions. 2 figs.

Temperature differential detection device

DOEpatents

Girling, Peter M.

1986-01-01

A temperature differential detection device for detecting the temperature differential between predetermined portions of a container wall is disclosed as comprising a Wheatstone bridge circuit for detecting resistance imbalance with a first circuit branch having a first elongated wire element mounted in thermal contact with a predetermined portion of the container wall, a second circuit branch having a second elongated wire element mounted in thermal contact with a second predetermined portion of a container wall with the wire elements having a predetermined temperature-resistant coefficient, an indicator interconnected between the first and second branches remote from the container wall for detecting and indicating resistance imbalance between the first and second wire elements, and connector leads for electrically connecting the wire elements to the remote indicator in order to maintain the respective resistance value relationship between the first and second wire elements. The indicator is calibrated to indicate the detected resistance imbalance in terms of a temperature differential between the first and second wall portions.

Impenetrable barriers for positrons in neighbourhood of superheavy nuclei with Z>118

NASA Astrophysics Data System (ADS)

Neznamov, V. P.

2017-12-01

Analysis of quantum mechanical motion of charged half-spin particles in the repulsive Coulomb field results in that an impenetrable potential barrier not explored earlier was found. For a particle at rest with a reduced mass m, the barrier radius is equal to half classical radius: the barrier radius decreases with increase in the particle energy. For the stable and quasi-stable nuclei with Z > 118, presence of an impenetrable barrier as β +-decay leads to the existence of “traps” for positrons in the neighbourhood of nuclei and as Zcr ≃ 170 (with emission of electron-positron pairs by vacuum) leads to the existence of a quasi-constant source of annihilation quanta.

Population and decay of a K π = 8 – two-quasineutron isomer in Pu 244

DOE PAGES

Hota, S. S.; Tandel, S. K.; Chowdhury, P.; ...

2016-08-22

Here, the decay of a K π = 8 – isomer in 244Pu and the collective band structures populating the isomer were studied using deep inelastic excitations with 47Ti and 208Pb beams, respectively. Precise measurements of M1/E2 branching ratios in the band confirm a 9/2 –[734] νⓍ7/2 +[624] ν configuration assignment for the isomer, validating the systematics of K π = 8 –, two-quasineutron isomers observed in even-Z, N = 150 isotones. These isomers around the deformed shell gap at N = 152 provide critical benchmarks for theoretical predictions of single-particle energies in this gateway region to superheavy nuclei.

Population and decay of a K π = 8 – two-quasineutron isomer in Pu 244

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hota, S. S.; Tandel, S. K.; Chowdhury, P.

Here, the decay of a K π = 8 – isomer in 244Pu and the collective band structures populating the isomer were studied using deep inelastic excitations with 47Ti and 208Pb beams, respectively. Precise measurements of M1/E2 branching ratios in the band confirm a 9/2 –[734] νⓍ7/2 +[624] ν configuration assignment for the isomer, validating the systematics of K π = 8 –, two-quasineutron isomers observed in even-Z, N = 150 isotones. These isomers around the deformed shell gap at N = 152 provide critical benchmarks for theoretical predictions of single-particle energies in this gateway region to superheavy nuclei.

An Overview of the History of Cluster Conferences

NASA Astrophysics Data System (ADS)

Horiuchi, H.

2017-06-01

An overview is given on the historical development of the cluster conference series which started at Bohum in 1969. I start with the discussion of the philosophy of Karl Wildermuth and then I make a review on the main subjects and topics in cluster conferences. Since the cluster dynamics is a main nuclear dynamics together with the mean-field dynamics, we see that development of the cluster conference has been along with the rises of many new subjects in nuclear physics itself. Examples of them include superheavy nuclei, nuclear astrophysics, neutron-rich nuclei, cluster-gas states and ab initio calculations. Finally I discuss that more activities in and attention to cluster physics are seen in recent days.

Dimensional reduction of the Standard Model coupled to a new singlet scalar field

NASA Astrophysics Data System (ADS)

Brauner, Tomáš; Tenkanen, Tuomas V. I.; Tranberg, Anders; Vuorinen, Aleksi; Weir, David J.

2017-03-01

We derive an effective dimensionally reduced theory for the Standard Model augmented by a real singlet scalar. We treat the singlet as a superheavy field and integrate it out, leaving an effective theory involving only the Higgs and SU(2) L × U(1) Y gauge fields, identical to the one studied previously for the Standard Model. This opens up the possibility of efficiently computing the order and strength of the electroweak phase transition, numerically and nonperturbatively, in this extension of the Standard Model. Understanding the phase diagram is crucial for models of electroweak baryogenesis and for studying the production of gravitational waves at thermal phase transitions.

DETECTION OF ELEMENTS AT ALL THREE r-PROCESS PEAKS IN THE METAL-POOR STAR HD 160617

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roederer, Ian U.; Lawler, James E., E-mail: iur@obs.carnegiescience.edu, E-mail: jelawler@wisc.edu

2012-05-01

We report the first detection of elements at all three r-process peaks in the metal-poor halo star HD 160617. These elements include arsenic and selenium, which have not been detected previously in halo stars, and the elements tellurium, osmium, iridium, and platinum, which have been detected previously. Absorption lines of these elements are found in archive observations made with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. We present up-to-date absolute atomic transition probabilities and complete line component patterns for these elements. Additional archival spectra of this star from several ground-based instruments allow us to derive abundancesmore » or upper limits of 45 elements in HD 160617, including 27 elements produced by neutron-capture reactions. The average abundances of the elements at the three r-process peaks are similar to the predicted solar system r-process residuals when scaled to the abundances in the rare earth element domain. This result for arsenic and selenium may be surprising in light of predictions that the production of the lightest r-process elements generally should be decoupled from the heavier r-process elements.« less

46 CFR 108.413 - Fusible element fire detection system.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Fusible element fire detection system. 108.413 Section 108.413 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems § 108.413 Fusible element fire detection system...

46 CFR 108.413 - Fusible element fire detection system.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Fusible element fire detection system. 108.413 Section 108.413 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems § 108.413 Fusible element fire detection system...

46 CFR 108.413 - Fusible element fire detection system.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Fusible element fire detection system. 108.413 Section 108.413 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems § 108.413 Fusible element fire detection system...

46 CFR 108.413 - Fusible element fire detection system.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Fusible element fire detection system. 108.413 Section 108.413 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems § 108.413 Fusible element fire detection system...

Artificial Boundary Conditions for Finite Element Model Update and Damage Detection

DTIC Science & Technology

2017-03-01

BOUNDARY CONDITIONS FOR FINITE ELEMENT MODEL UPDATE AND DAMAGE DETECTION by Emmanouil Damanakis March 2017 Thesis Advisor: Joshua H. Gordis...REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE ARTIFICIAL BOUNDARY CONDITIONS FOR FINITE ELEMENT MODEL UPDATE AND DAMAGE DETECTION...release. Distribution is unlimited. 12b. DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) In structural engineering, a finite element model is often

Feasibility of the detection of trace elements in particulate matter using online High-Resolution Aerosol Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salcedo, D.; Laskin, Alexander; Shutthanandan, V.

The feasibility of using an online thermal-desorption electron-ionization high-resolution aerosol mass spectrometer (AMS) for the detection of particulate trace elements was investigated analyzing data from Mexico City obtained during the MILAGRO 2006 field campaign, where relatively high concentrations of trace elements have been reported. This potential application is of interest due to the real-time data provided by the AMS, its high sensitivity and time resolution, and the widespread availability and use of this instrument. High resolution mass spectral analysis, isotopic ratios, and ratios of different ions containing the same elements are used to constrain the chemical identity of the measuredmore » ions. The detection of Cu, Zn, As, Se, Sn, and Sb is reported. There was no convincing evidence for the detection of other trace elements commonly reported in PM. The elements detected tend to be those with lower melting and boiling points, as expected given the use of a vaporizer at 600oC in this instrument. Operation of the AMS vaporizer at higher temperatures is likely to improve trace element detection. The detection limit is estimated at approximately 0.3 ng m-3 for 5-min of data averaging. Concentration time series obtained from the AMS data were compared to concentration records determined from offline analysis of particle samples from the same times and locations by ICP (PM2.5) and PIXE (PM1.1 and PM0.3). The degree of correlation and agreement between the three instruments (AMS, ICP, and PIXE) varied depending on the element. The AMS shows promise for real-time detection of some trace elements, although additional work including laboratory calibrations with different chemical forms of these elements are needed to further develop this technique and to understand the differences with the ambient data from the other techniques. The trace elements peaked in the morning as expected for primary sources, and the many detected plumes suggest the presence of multiple point sources, probably industrial, in Mexico City which are variable in time and space, in agreement with previous studies.« less

Fission barriers at the end of the chart of the nuclides

DOE PAGES

Möller, Peter; Sierk, Arnold J.; Ichikawa, Takatoshi; ...

2015-02-12

We present calculated fission-barrier heights for 5239 nuclides for all nuclei between the proton and neutron drip lines with 171 ≤ A ≤ 330. The barriers are calculated in the macroscopic-microscopic finite-range liquid-drop (FRLDM) with a 2002 set of macroscopic-model parameters. The saddle-point energies are determined from potential-energy surfaces based on more than five million different shapes, defined by five deformation parameters in the three-quadratic-surface shape parametrization: elongation, neck diameter, left-fragment spheroidal deformation, right-fragment spheroidal deformation, and nascent-fragment mass asymmetry. The energy of the ground state is determined by calculating the lowest-energy configuration in both the Nilsson perturbed-spheroid (ϵ) andmore » the spherical-harmonic (β) parametrizations, including axially asymmetric deformations. The lower of the two results (correcting for zero-point motion) is defined as the ground-state energy. The effect of axial asymmetry on the inner barrier peak is calculated in the (ϵ,γ) parametrization. We have earlier benchmarked our calculated barrier heights to experimentally extracted barrier parameters and found average agreement to about one MeV for known data across the nuclear chart. Here we do additional benchmarks and investigate the qualitative and, when possible, quantitative agreement and/or consistency with data on β-delayed fission, isotope generation along prompt-neutron-capture chains in nuclear-weapons tests, and superheavy-element stability. In addition these studies all indicate that the model is realistic at considerable distances in Z and N from the region of nuclei where its parameters were determined.« less

The 1064 nm laser-induced breakdown spectroscopy (LIBS) inspection to detect the nutrient elements in freshly cut carrot samples

NASA Astrophysics Data System (ADS)

Yudasari, N.; Prasetyo, S.; Suliyanti, M. M.

2018-03-01

The laser-induced breakdown spectroscopy (LIBS) technique was applied to detect the nutrient elements contained in fresh carrot. Nd:YAG laser the wavelength of 1064 nm was employed in the experiments for ablation. Employing simple set-up of LIBS and preparing the sample with less step method, we are able to detect 18 chemical elements including some fundamental element of carrot, i.e Mg, Al, Fe, Mn, Ti, Ca, and Mn. By applying normalized profiles calculation on some of the element, we are able to compare the concentration level of each element of the outer and inner part of carrot.

Method and apparatus for acoustic plate mode liquid-solid phase transition detection

DOEpatents

Blair, Dianna S.; Freye, Gregory C.; Hughes, Robert C.; Martin, Stephen J.; Ricco, Antonio J.

1993-01-01

A method and apparatus for sensing a liquid-solid phase transition event is provided which comprises an acoustic plate mode detecting element placed in contact with a liquid or solid material which generates a high-frequency acoustic wave that is attenuated to an extent based on the physical state of the material is contact with the detecting element. The attenuation caused by the material in contact with the acoustic plate mode detecting element is used to determine the physical state of the material being detected. The method and device are particularly suited for detecting conditions such as the icing and deicing of wings of an aircraft. In another aspect of the present invention, a method is provided wherein the adhesion of a solid material to the detecting element can be measured using the apparatus of the invention.

ElemeNT: a computational tool for detecting core promoter elements.

PubMed

Sloutskin, Anna; Danino, Yehuda M; Orenstein, Yaron; Zehavi, Yonathan; Doniger, Tirza; Shamir, Ron; Juven-Gershon, Tamar

2015-01-01

Core promoter elements play a pivotal role in the transcriptional output, yet they are often detected manually within sequences of interest. Here, we present 2 contributions to the detection and curation of core promoter elements within given sequences. First, the Elements Navigation Tool (ElemeNT) is a user-friendly web-based, interactive tool for prediction and display of putative core promoter elements and their biologically-relevant combinations. Second, the CORE database summarizes ElemeNT-predicted core promoter elements near CAGE and RNA-seq-defined Drosophila melanogaster transcription start sites (TSSs). ElemeNT's predictions are based on biologically-functional core promoter elements, and can be used to infer core promoter compositions. ElemeNT does not assume prior knowledge of the actual TSS position, and can therefore assist in annotation of any given sequence. These resources, freely accessible at http://lifefaculty.biu.ac.il/gershon-tamar/index.php/resources, facilitate the identification of core promoter elements as active contributors to gene expression.

Systematic study on the competition between α-decay and spontaneous fission of superheavy nuclei

NASA Astrophysics Data System (ADS)

Zhang, Y. L.; Wang, Y. Z.

2017-10-01

The competition between α-decay and spontaneous fission (SF) of Z = 112 isotopes are studied. The α-decay half-lives are estimated by the generalized liquid-drop model (GLDM) and several sets of analytic formulas. These formulas include the Royer formula, Viola-Seaborg semiempirical (VSS) formula and universal decay law (UDL). For the SF, its half-lives are calculated by using the Xu, Ren, Karpov and Santhosh formulas. It is shown that the predicted α-decay half-lives by different approaches are more or less identical. However, the SF half-lives are highly sensitive to models. To test the accuracies of different SF formulas, the half-lives of 56 even-even heavy nuclei are calculated by these formulas. By comparing with the experimental data, it is found that the Xu formula is the most accurate one to reproduce the experimental SF half-lives. This allows us to make a systematic prediction on the competition between α-decay and SF of even-even superheavy nuclei (SHN) with Z = 104- 120 by using the Xu formula and the above mentioned models on α-decay. The calculations suggest that 258,260104, 268-276110, 270-280112, 272-286114, 274-294116, 284-302118 and 292-308120 have smaller α-decay half-lives than those of SF. Thus these nuclei can be synthesized and identified via α-decay in the laboratory. In addition, it is observed that N = 162, 178, 184 and 196 may be the submagic or magic numbers. Finally, an extensive study on the possible α-decay chains for Z = 120 isotopes is performed. It is predicted that six sequential α-decay chains can be observed from 292-296120, four α-decay chains from 298120, three α-decay chains from 300,302120, two α-decay chains from 304,306120, and only one α-decay chain from 308120. These nuclei are the most likely candidates to be synthesized experimentally via α-decay in the near future.

Methods for detecting the mobility of trace elements during medium-temperature pyrolysis

USGS Publications Warehouse

Shiley, R.H.; Konopka, K.L.; Cahill, R.A.; Hinckley, C.C.; Smith, Gerard V.; Twardowska, H.; Saporoschenko, Mykola

1983-01-01

The mobility (volatility) of trace elements in coal during pyrolysis has been studied for distances of up to 40 cm between the coal and the trace element collector, which was graphite or a baffled solvent trap. Nineteen elements not previously recorded as mobile were detected. ?? 1983.

Development of an X-ray surface analyzer for planetary exploration

NASA Technical Reports Server (NTRS)

Clark, B. C.

1972-01-01

An ultraminiature X-ray fluorescence spectrometer was developed which can obtain data on element composition not provided by present spacecraft instrumentation. The apparatus employs two radioisotope sources (Fe-55 and Cd-109) which irradiate adjacent areas on a soil sample. Fluorescent X-rays emitted by the sample are detected by four thin-window proportional counters. Using pulse-height discrimination, the energy spectra are determined. Virtually all elements above sodium in the periodic table are detected if present at sufficient levels. Minimum detection limits range from 30 ppm to several percent, depending upon the element and the matrix. For most elements, they are below 0.5 percent. Accuracies likewise depend upon the matrix, but are generally better than plus or minus 0.5 percent for all elements of atomic number greater than 14. Elements below sodium are also detected, but as a single group.

Construction of 2,4,6-Trinitrotoluene Biosensors with Novel Sensing Elements from Escherichia coli K-12 MG1655.

PubMed

Tan, Junjie; Kan, Naipeng; Wang, Wei; Ling, Jingyi; Qu, Guolong; Jin, Jing; Shao, Yu; Liu, Gang; Chen, Huipeng

2015-06-01

Detection of 2,4,6-trinitrotoluene (TNT) has been extensively studied since it is a common explosive filling for landmines, posing significant threats to the environment and human safety. The rapid advances in synthetic biology give new hope to detect such toxic and hazardous compounds in a more sensitive and safe way. Biosensor construction anticipates finding sensing elements able to detect TNT. As TNT can induce some physiological responses in E. coli, it may be useful to define the sensing elements from E. coli to detect TNT. An E. coli MG1655 genomic promoter library containing nearly 5,400 elements was constructed. Five elements, yadG, yqgC, aspC, recE, and topA, displayed high sensing specificity to TNT and its indicator compounds 1,3-DNB and 2,4-DNT. Based on this, a whole cell biosensor was constructed using E. coli, in which green fluorescent protein was positioned downstream of the five sensing elements via genetic fusion. The threshold value, detection time, EC200 value, and other aspects of five sensing elements were determined and the minimum responding concentration to TNT was 4.75 mg/L. According to the synthetic biology, the five sensing elements enriched the reservoir of TNT-sensing elements, and provided a more applicable toolkit to be applied in genetic routes and live systems of biosensors in future.

Nuclear Security: Quantifying Late Detection in MC&A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Surinder Paul; Gibbs, Philip W.; Bultz, Garl A.

2014-03-01

The objectives of this presentation are to understand the concept of late detection; review the statistics used in MC&A; specify the Pd and timelines for Pd for MC&A elements for item inventories; review elements of process control as they relate to bulk processes; and specify the timelines and detection thresholds for Pd for MC&A elements for bulk or Processing Operations.

The Effect of Local Orientation Change on the Detection of Contours Defined by Constant Curvature: Psychophysics and Image Statistics.

PubMed

Khuu, Sieu K; Cham, Joey; Hayes, Anthony

2016-01-01

In the present study, we investigated the detection of contours defined by constant curvature and the statistics of curved contours in natural scenes. In Experiment 1, we examined the degree to which human sensitivity to contours is affected by changing the curvature angle and disrupting contour curvature continuity by varying the orientation of end elements. We find that (1) changing the angle of contour curvature decreased detection performance, while (2) end elements oriented in the direction (i.e., clockwise) of curvature facilitated contour detection regardless of the curvature angle of the contour. In Experiment 2 we further established that the relative effect of end-element orientation on contour detection was not only dependent on their orientation (collinear or cocircular), but also their spatial separation from the contour, and whether the contour shape was curved or not (i.e., C-shaped or S-shaped). Increasing the spatial separation of end-elements reduced contour detection performance regardless of their orientation or the contour shape. However, at small separations, cocircular end-elements facilitated the detection of C-shaped contours, but not S-shaped contours. The opposite result was observed for collinear end-elements, which improved the detection of S- shaped, but not C-shaped contours. These dissociative results confirmed that the visual system specifically codes contour curvature, but the association of contour elements occurs locally. Finally, we undertook an analysis of natural images that mapped contours with a constant angular change and determined the frequency of occurrence of end elements with different orientations. Analogous to our behavioral data, this image analysis revealed that the mapped end elements of constantly curved contours are likely to be oriented clockwise to the angle of curvature. Our findings indicate that the visual system is selectively sensitive to contours defined by constant curvature and that this might reflect the properties of curved contours in natural images.

Elemental composition of edible nuts: fast optimization and validation procedure of an ICP-OES method.

PubMed

Tošić, Snežana B; Mitić, Snežana S; Velimirović, Dragan S; Stojanović, Gordana S; Pavlović, Aleksandra N; Pecev-Marinković, Emilija T

2015-08-30

An inductively coupled plasma-optical emission spectrometry method for the speedy simultaneous detection of 19 elements in edible nuts (walnuts: Juglans nigra; almonds: Prunus dulcis; hazelnuts: Corylus avellana; Brazil nuts: Bertholletia excelsa; cashews: Anacardium occidentalle; pistachios: Pistacia vera; and peanuts: Arachis hypogaea) available on the Serbian markets, was optimized and validated through the selection of instrumental parameters and analytical lines free from spectral interference and with the lowest matrix effects. The analysed macro-elements were present in the following descending order: Na > Mg > Ca > K. Of all the trace elements, the tested samples showed the highest content of Fe. The micro-element Se was detected in all the samples of nuts. The toxic elements As, Cd and Pb were either not detected or the contents were below the limit of detection. One-way analysis of variance, Student's t-test, Tukey's HSD post hoc test and hierarchical agglomerative cluster analysis were applied in the statistical analysis of the results. Based on the detected content of analysed elements it can be concluded that nuts may be a good additional source of minerals as micronutrients. © 2014 Society of Chemical Industry.

Detection of pristine gas two billion years after the Big Bang.

PubMed

Fumagalli, Michele; O'Meara, John M; Prochaska, J Xavier

2011-12-02

In the current cosmological model, only the three lightest elements were created in the first few minutes after the Big Bang; all other elements were produced later in stars. To date, however, heavy elements have been observed in all astrophysical environments. We report the detection of two gas clouds with no discernible elements heavier than hydrogen. These systems exhibit the lowest heavy-element abundance in the early universe, and thus are potential fuel for the most metal-poor halo stars. The detection of deuterium in one system at the level predicted by primordial nucleosynthesis provides a direct confirmation of the standard cosmological model. The composition of these clouds further implies that the transport of heavy elements from galaxies to their surroundings is highly inhomogeneous.

Theoretical studies on the synthesis of SHE 290-302Og (Z=118) using 48Ca, 45Sc, 50Ti, 51V, 54Cr, 55Mn, 58Fe, 59Co and 64Ni induced reactions

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Safoora, V.

2018-05-01

Using the phenomenological model for production cross section (PMPC), the production cross sections for the synthesis of isotopes of superheavy element Og ( Z = 118) using the fusion reactions 48Ca+249-254Cf → 297-302Og, 45Sc+247,249Bk → 292,294Og, 50Ti + 242-248,250Cm → 292-298,300Og, 51V+241,243Am → 292,294Og, 54Cr + 238-242,244Pu → 292-296,298Og, 55Mn + 235-237Np → 290-292Og, 58Fe + 232-236, 238U → 290-294,296Og, 59Co + 231Pa → 290Og, and 64Ni + 228-230,232Cm → 292-294,296Og in xn (x=3,4,5) evaporation channel have been systematically studied at energies near and above the Coulomb barrier. We have predicted most suitable projectile-target combinations for the synthesis of isotopes 290-302Og among these reactions. Our calculated evaporation residue (ER) cross section values for the reaction 48Ca + 249Cf → 297Og is in excellent agreement with available experimental values. For the synthesis of Og, among all the reactions mentioned above, the 3n channel cross section (2458 fb) is larger for 48Ca + 251Cf → 299Og; 4n channel cross section (212 fb) is larger for 48Ca + 252Cf → 300Og and 5n channel cross section (34 fb) is larger for 48Ca + 253Cf → 301Og. The second largest 3n channel cross section (1143 fb) is obtained for the reaction, 50Ti + 245Cm → 295Og. Our studies will be useful for the future experiments to synthesize the isotopes of element Og which are not synthesized so far. We have also studied the effect of the use of mass values and shell correction of the Warsaw group which leads to a smaller ER cross section compared to the Moller group.

Spark discharge trace element detection system

DOEpatents

Adler-Golden, Steven; Bernstein, Lawrence S.; Bien, Fritz

1988-01-01

A spark discharge trace element detection system is provided which includes a spark chamber including a pair of electrodes for receiving a sample of gas to be analyzed at no greater than atmospheric pressure. A voltage is provided across the electrodes for generating a spark in the sample. The intensity of the emitted radiation in at least one primary selected narrow band of the radiation is detected. Each primary band corresponds to an element to be detected in the gas. The intensity of the emission in each detected primary band is integrated during the afterglow time interval of the spark emission and a signal representative of the integrated intensity of the emission in each selected primary bond is utilized to determine the concentration of the corresponding element in the gas.

Spark discharge trace element detection system

DOEpatents

Adler-Golden, S.; Bernstein, L.S.; Bien, F.

1988-08-23

A spark discharge trace element detection system is provided which includes a spark chamber including a pair of electrodes for receiving a sample of gas to be analyzed at no greater than atmospheric pressure. A voltage is provided across the electrodes for generating a spark in the sample. The intensity of the emitted radiation in at least one primary selected narrow band of the radiation is detected. Each primary band corresponds to an element to be detected in the gas. The intensity of the emission in each detected primary band is integrated during the afterglow time interval of the spark emission and a signal representative of the integrated intensity of the emission in each selected primary bond is utilized to determine the concentration of the corresponding element in the gas. 12 figs.

Enhanced radiation detectors using luminescent materials

DOEpatents

Vardeny, Zeev V.; Jeglinski, Stefan A.; Lane, Paul A.

2001-01-01

A radiation detecting device comprising a radiation sensing element, and a layer of luminescent material to expand the range of wavelengths over which the sensing element can efficiently detect radiation. The luminescent material being selected to absorb radiation at selected wavelengths, causing the luminescent material to luminesce, and the luminescent radiation being detected by the sensing element. Radiation sensing elements include photodiodes (singly and in arrays), CCD arrays, IR detectors and photomultiplier tubes. Luminescent materials include polymers, oligomers, copolymers and porphyrines, Luminescent layers include thin films, thicker layers, and liquid polymers.

Fault Analysis and Detection in Microgrids with High PV Penetration

DOE Office of Scientific and Technical Information (OSTI.GOV)

El Khatib, Mohamed; Hernandez Alvidrez, Javier; Ellis, Abraham

In this report we focus on analyzing current-controlled PV inverters behaviour under faults in order to develop fault detection schemes for microgrids with high PV penetration. Inverter model suitable for steady state fault studies is presented and the impact of PV inverters on two protection elements is analyzed. The studied protection elements are superimposed quantities based directional element and negative sequence directional element. Additionally, several non-overcurrent fault detection schemes are discussed in this report for microgrids with high PV penetration. A detailed time-domain simulation study is presented to assess the performance of the presented fault detection schemes under different microgridmore » modes of operation.« less

Optical sensing elements for nitrogen dioxide (NO.sub.2) gas detection, a sol-gel method for making the sensing elements and fiber optic sensors incorporating nitrogen dioxide gas optical sensing elements

DOEpatents

Mechery, Shelly John [Mississippi State, MS; Singh, Jagdish P [Starkville, MS

2007-07-03

A sensing element, a method of making a sensing element, and a fiber optic sensor incorporating the sensing element are described. The sensor can be used for the quantitative detection of NO.sub.2 in a mixture of gases. The sensing element can be made by incorporating a diazotizing reagent which reacts with nitrous ions to produce a diazo compound and a coupling reagent which couples with the diazo compound to produce an azo dye into a sol and allowing the sol to form an optically transparent gel. The sensing element changes color in the presence of NO.sub.2 gas. The temporal response of the absorption spectrum at various NO.sub.2 concentrations has also been recorded and analyzed. Sensors having different design configurations are described. The sensing element can detect NO.sub.2 gas at levels of parts per billion.

Portable TXRF Spectrometer with 10{sup -11}g Detection Limit and Portable XRF Spectromicroscope with Sub-mm Spatial Resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kunimura, Shinsuke; Hatakeyama, So; Sasaki, Nobuharu

A portable total reflection X-ray fluorescence (TXRF) spectrometer that we have developed is applied to trace elemental analysis of water solutions. Although a 5 W X-ray tube is used in the portable TXRF spectrometer, detection limits of several ppb are achieved for 3d transition metal elements and trace elements in a leaching solution of soils, a leaching solution of solder, and alcoholic beverages are detected. Portable X-ray fluorescence (XRF) spectromicroscopes with a 1 W X-ray tube and an 8 W X-ray tube are also presented. Using the portable XRF spectromicroscope with the 1 W X-ray tube, 93 ppm of Crmore » is detected with an about 700 {mu}m spatial resolution. Spatially resolved elemental analysis of a mug painted with blue, red, green, and white is performed using the two portable spectromicroscopes, and the difference in elemental composition at each paint is detected.« less

Characterizing and Detecting Unrevealed Elements of Network Systems

DTIC Science & Technology

2009-03-01

refers to the direct interaction of persons in so far as this affects the future behavior or attitude of participants (such that this differs from... CHARACTERIZING AND DETECTING UNREVEALED ELEMENTS OF NETWORK SYSTEMS DISSERTATION James A. Leinart, Lieutenant Colonel, USAF AFIT/DS/ENS/08-01W...Air Force, Department of Defense or the United States Government. AFIT/DS/ENS/08-01W CHARACTERIZING AND DETECTING UNREVEALED ELEMENTS OF NETWORK

Actinide targets for fundamental research in nuclear physics

NASA Astrophysics Data System (ADS)

Eberhardt, K.; Düllmann, Ch. E.; Haas, R.; Mokry, Ch.; Runke, J.; Thörle-Pospiech, P.; Trautmann, N.

2018-05-01

Thin actinide layers deposited on various substrates are widely used as calibration sources in nuclear spectroscopy. Other applications include fundamental research in nuclear chemistry and -physics, e.g., the chemical and physical properties of super-heavy elements (SHE, Z > 103) or nuclear reaction studies with heavy ions. For the design of future nuclear reactors like fast-fission reactors and accelerator-driven systems for transmutation of nuclear waste, precise data for neutron absorption as well as neutron-induced fission cross section data for 242Pu with neutrons of different energies are of particular importance, requiring suitable Pu-targets. Another application includes studies of nuclear transitions in 229Th harvested as α-decay recoil product from a thin layer of its 233U precursor. For this, a thin and very smooth layer of 233U is used. We report here on the production of actinide layers mostly obtained by Molecular Plating (MP). MP is currently the only fabrication method in cases where the desired actinide material is available only in very limited amounts or possesses a high specific activity. Here, deposition is performed from organic solution applying a current density of 1-2 mA/cm2. Under these conditions target thicknesses of 500-1000 μg/cm2 are possible applying a single deposition step with deposition yields approaching 100 %. For yield determination α-particle spectroscopy, γ-spectroscopy and Neutron Activation Analysis is routinely used. Layer homogeneity is checked with Radiographic Imaging. As an alternative technique to MP the production of thin lanthanide and actinide layers by the so-called "Drop on Demand"-technique applied e.g., in ink-jet printing is currently under investigation.

Interplay of spherical closed shells and N /Z asymmetry in quasifission dynamics

NASA Astrophysics Data System (ADS)

Mohanto, G.; Hinde, D. J.; Banerjee, K.; Dasgupta, M.; Jeung, D. Y.; Simenel, C.; Simpson, E. C.; Wakhle, A.; Williams, E.; Carter, I. P.; Cook, K. J.; Luong, D. H.; Palshetkar, C. S.; Rafferty, D. C.

2018-05-01

Background: Quasifission (QF) has gained tremendous importance in heavy-ion nuclear physics research because of its strong influence on superheavy-element synthesis. Collisions involving closed-shell nuclei in the entrance channel are found to affect the QF reaction mechanism. Hence, it is important to improve the understanding of their effect on QF. Apart from that, some recent studies show that the difference in N /Z of reaction partners influences the reaction dynamics. Since heavier doubly magic nuclei have different N /Z than lighter doubly magic nuclei, it is important to understand the effect of N /Z mismatch as well as the effect of shell closures. Purpose: To investigate the effect of entrance-channel shell closures and N /Z asymmetry on QF. The reactions were chosen to decouple these effects from the contributions of other entrance-channel parameters. Method: Fission fragment mass-angle distributions were measured using the CUBE fission spectrometer, consisting of two large area position-sensitive multi-wire proportional counters (MWPCs), for five reactions, namely, 50Cr+208Pb , 52Cr+Pb,208206 , 54Cr+Pb,208204 . Result: Two components were observed in the measured fragment mass angle distribution, a fast mass-asymmetric quasifission and a slow mass-symmetric component having a less significant mass-angle correlation. The ratio of these components was found to depend on spherical closed shells in the entrance channel nuclei and the magnitude of the N /Z mismatch between the two reaction partners, as well as the beam energy. Conclusions: Entrance-channel spherical closed shells can enhance compound nucleus formation provided the N /Z asymmetry is small. Increase in the N /Z asymmetry is expected to destroy the effect of entrance-channel spherical closed shells, through nucleon transfer reactions.

Californium Electrodepositions at Oak Ridge National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boll, Rose Ann

2015-01-01

Electrodepositions of californium isotopes were successfully performed at Oak Ridge National Laboratory (ORNL) during the past year involving two different types of deposition solutions, ammonium acetate (NH 4C 2H 3O 2) and isobutanol ((CH 3) 2CHCH 2OH). A californium product that was decay enriched in 251Cf was recovered for use in super-heavy element (SHE) research. This neutron-rich isotope, 251Cf, provides target material for SHE research for the potential discovery of heavier isotopes of Z=118. The californium material was recovered from aged 252Cf neutron sources in storage at ORNL. These sources have decayed for over 30 years, thus providing material withmore » a very high 251Cf-to- 252Cf ratio. After the source capsules were opened, the californium was purified and then electrodeposited using the isobutanol method onto thin titanium foils for use in an accelerator at the Joint Institute for Nuclear Research in Dubna, Russia. Another deposition method, ammonium acetate, was used to produce a deposition containing 1.7 0.1 Ci of 252Cf onto a stainless steel substrate. This was the largest single electrodeposition of 252Cf ever prepared. The 252Cf material was initially purified using traditional ion exchange media, such as AG50-AHIB and AG50-HCl, and further purified using a TEVA-NH 4SCN system to remove any lanthanides, resulting in the recovery of 3.6 0.1 mg of purified 252Cf. The ammonium acetate deposition was run with a current of 1.0 amp, resulting in a 91.5% deposition yield. Purification and handling of the highly radioactive californium material created additional challenges in the production of these sources.« less

Deep convolutional networks for automated detection of posterior-element fractures on spine CT

NASA Astrophysics Data System (ADS)

Roth, Holger R.; Wang, Yinong; Yao, Jianhua; Lu, Le; Burns, Joseph E.; Summers, Ronald M.

2016-03-01

Injuries of the spine, and its posterior elements in particular, are a common occurrence in trauma patients, with potentially devastating consequences. Computer-aided detection (CADe) could assist in the detection and classification of spine fractures. Furthermore, CAD could help assess the stability and chronicity of fractures, as well as facilitate research into optimization of treatment paradigms. In this work, we apply deep convolutional networks (ConvNets) for the automated detection of posterior element fractures of the spine. First, the vertebra bodies of the spine with its posterior elements are segmented in spine CT using multi-atlas label fusion. Then, edge maps of the posterior elements are computed. These edge maps serve as candidate regions for predicting a set of probabilities for fractures along the image edges using ConvNets in a 2.5D fashion (three orthogonal patches in axial, coronal and sagittal planes). We explore three different methods for training the ConvNet using 2.5D patches along the edge maps of `positive', i.e. fractured posterior-elements and `negative', i.e. non-fractured elements. An experienced radiologist retrospectively marked the location of 55 displaced posterior-element fractures in 18 trauma patients. We randomly split the data into training and testing cases. In testing, we achieve an area-under-the-curve of 0.857. This corresponds to 71% or 81% sensitivities at 5 or 10 false-positives per patient, respectively. Analysis of our set of trauma patients demonstrates the feasibility of detecting posterior-element fractures in spine CT images using computer vision techniques such as deep convolutional networks.

Photoacoustic method for measuring concentration of chemical species

DOEpatents

Autrey, S Thomas [West Richland, WA; Posakony, Gerald J [Richland, WA; Amonette, James E [Richland, WA; Foster-Mills, Nancy S [Richland, WA

2001-01-01

The present invention is a transducer for photoacoustic detection having at least two piezoelectric elements wherein at least a first piezoelectric element has a first frequency and at least a second piezoelectric element has a second frequency. The improvement according to the present invention is that at least two piezoelectric elements are longitudinal elements for longitudinal waves; and the first frequency is different from said second frequency. In other words, the invention is a multi-frequency longitudinal transducer for photoacoustic detection.

Movable Genetic Elements: Detection of Changes in Maize DNA at the Shrunken Locus Due to the Intervention of Ds Elements

DOE R&D Accomplishments Database

Burr, B.; Burr, F.A.

1980-05-28

This report describes our initial attempts at the molecular characterization of a maize controlling element. We have prepared a cDNA probe and used it to detect changes at a locus where Ds elements are found. Evidence of their presence are indicated by changes in the restriction patterns, but there is as yet no information on the physical nature of the controlling elements nor on the kinds of rearrangements they cause.

Development and validation of real-time PCR screening methods for detection of cry1A.105 and cry2Ab2 genes in genetically modified organisms.

PubMed

Dinon, Andréia Z; Prins, Theo W; van Dijk, Jeroen P; Arisi, Ana Carolina M; Scholtens, Ingrid M J; Kok, Esther J

2011-05-01

Primers and probes were developed for the element-specific detection of cry1A.105 and cry2Ab2 genes, based on their DNA sequence as present in GM maize MON89034. Cry genes are present in many genetically modified (GM) plants and they are important targets for developing GMO element-specific detection methods. Element-specific methods can be of use to screen for the presence of GMOs in food and feed supply chains. Moreover, a combination of GMO elements may indicate the potential presence of unapproved GMOs (UGMs). Primer-probe combinations were evaluated in terms of specificity, efficiency and limit of detection. Except for specificity, the complete experiment was performed in 9 PCR runs, on 9 different days and by testing 8 DNA concentrations. The results showed a high specificity and efficiency for cry1A.105 and cry2Ab2 detection. The limit of detection was between 0.05 and 0.01 ng DNA per PCR reaction for both assays. These data confirm the applicability of these new primer-probe combinations for element detection that can contribute to the screening for GM and UGM crops in food and feed samples.

Method and apparatus for detecting and determining event characteristics with reduced data collection

NASA Technical Reports Server (NTRS)

Totman, Peter D. (Inventor); Everton, Randy L. (Inventor); Egget, Mark R. (Inventor); Macon, David J. (Inventor)

2007-01-01

A method and apparatus for detecting and determining event characteristics such as, for example, the material failure of a component, in a manner which significantly reduces the amount of data collected. A sensor array, including a plurality of individual sensor elements, is coupled to a programmable logic device (PLD) configured to operate in a passive state and an active state. A triggering event is established such that the PLD records information only upon detection of the occurrence of the triggering event which causes a change in state within one or more of the plurality of sensor elements. Upon the occurrence of the triggering event, the change in state of the one or more sensor elements causes the PLD to record in memory which sensor element detected the event and at what time the event was detected. The PLD may be coupled with a computer for subsequent downloading and analysis of the acquired data.

A tactile sensing element based on a hetero-core optical fiber for force measurement and texture detection

NASA Astrophysics Data System (ADS)

Yamazaki, Hiroshi; Koyama, Yuya; Watanabe, Kazuhiro

2014-05-01

Tactile sensing technology can measure a given property of an object through physical contact between a sensing element and the object. Various tactile sensing techniques have been developed for several applications such as intelligent robots, tactile interface, medical support and nursing care support. A desirable tactile sensing element for supporting human daily life can be embedded in the soft material with high sensitivity and accuracy in order to prevent from damaging to human or object physically. This report describes a new tactile sensing element. Hetero-core optical fibers have high sensitivity of macro-bending at local sensor portion and temperature independency, including advantages of optical fiber itself; thin size, light weight, flexible transmission line, and immunity to electro-magnetic interference. The proposed tactile sensing element could detect textures of touched objects through the optical loss caused by the force applied to the sensing element. The characteristics of the sensing element have been evaluated, in which the sensing element has the monotonic and non-linear sensitivity against the normal force ranged from 0 to 5 N with lower accuracy than 0.25 dB. Additionally, texture detection have been successfully demonstrated in which small surface figures of 0.1 mm in height were detected with spatial resolution of 0.4 mm.

Kinetics analysis and quantitative calculations for the successive radioactive decay process

NASA Astrophysics Data System (ADS)

Zhou, Zhiping; Yan, Deyue; Zhao, Yuliang; Chai, Zhifang

2015-01-01

The general radioactive decay kinetics equations with branching were developed and the analytical solutions were derived by Laplace transform method. The time dependence of all the nuclide concentrations can be easily obtained by applying the equations to any known radioactive decay series. Taking the example of thorium radioactive decay series, the concentration evolution over time of various nuclide members in the family has been given by the quantitative numerical calculations with a computer. The method can be applied to the quantitative prediction and analysis for the daughter nuclides in the successive decay with branching of the complicated radioactive processes, such as the natural radioactive decay series, nuclear reactor, nuclear waste disposal, nuclear spallation, synthesis and identification of superheavy nuclides, radioactive ion beam physics and chemistry, etc.

Detection of trace metallic elements in oral lichenoid contact lesions using SR-XRF, PIXE, and XAFS

PubMed Central

Sugiyama, Tomoko; Uo, Motohiro; Wada, Takahiro; Omagari, Daisuke; Komiyama, Kazuo; Miyazaki, Serika; Numako, Chiya; Noguchi, Tadahide; Jinbu, Yoshinori; Kusama, Mikio; Mori, Yoshiyuki

2015-01-01

Oral lichen planus (OLP) and oral lichenoid contact lesions (OLCL) are chronic inflammatory mucocutaneous reactions with a risk of malignant transformation that alter the epithelium. OLP and OLCL have similar clinical and histopathological features and it is difficult to distinguish one from the other. Metallic restorations are suspected to generate OLCLs. Trace metal analysis of OLCL specimens may facilitate the discrimination of symptoms and identification of causative metallic restorations. The purpose of this study was to assess OLCL tissue samples for the prevalence of metallic elements derived from dental restorations, and to discriminate OLCL from OLP by using synchrotron radiation-excited X-ray fluorescence analysis (SR-XRF), particle-induced X-ray emission (PIXE), and X-ray absorption fine structure (XAFS). Typical elements of dental materials were detected in the OLCL, whereas no obvious element accumulation was detected in OLP and negative control specimens. The origin of the detected metallic elements was presumed to be dental alloys through erosion. Therefore, our findings support the feasibility of providing supporting information to distinguish OLCL from OLP by using elemental analysis. PMID:26085368

Cantilevered probe detector with piezoelectric element

DOEpatents

Adams, Jesse D; Sulchek, Todd A; Feigin, Stuart C

2014-04-29

A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

Cantilevered probe detector with piezoelectric element

DOEpatents

Adams, Jesse D; Sulchek, Todd A; Feigin, Stuart C

2013-04-30

A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

Cantilevered probe detector with piezoelectric element

DOEpatents

Adams, Jesse D [Reno, NV; Sulchek, Todd A [Oakland, CA; Feigin, Stuart C [Reno, NV

2012-07-10

A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

Cantilevered probe detector with piezoelectric element

DOEpatents

Adams, Jesse D.; Sulchek, Todd A.; Feigin, Stuart C.

2010-04-06

A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

Detection of Chorus Elements and other Wave Signatures Using Geometric Computational Techniques in the Van Allen radiation belts

NASA Astrophysics Data System (ADS)

Sengupta, A.; Kletzing, C.; Howk, R.; Kurth, W. S.

2017-12-01

An important goal of the Van Allen Probes mission is to understand wave particle interactions that can energize relativistic electron in the Earth's Van Allen radiation belts. The EMFISIS instrumentation suite provides measurements of wave electric and magnetic fields of wave features such as chorus that participate in these interactions. Geometric signal processing discovers structural relationships, e.g. connectivity across ridge-like features in chorus elements to reveal properties such as dominant angles of the element (frequency sweep rate) and integrated power along the a given chorus element. These techniques disambiguate these wave features against background hiss-like chorus. This enables autonomous discovery of chorus elements across the large volumes of EMFISIS data. At the scale of individual or overlapping chorus elements, topological pattern recognition techniques enable interpretation of chorus microstructure by discovering connectivity and other geometric features within the wave signature of a single chorus element or between overlapping chorus elements. Thus chorus wave features can be quantified and studied at multiple scales of spectral geometry using geometric signal processing techniques. We present recently developed computational techniques that exploit spectral geometry of chorus elements and whistlers to enable large-scale automated discovery, detection and statistical analysis of these events over EMFISIS data. Specifically, we present different case studies across a diverse portfolio of chorus elements and discuss the performance of our algorithms regarding precision of detection as well as interpretation of chorus microstructure. We also provide large-scale statistical analysis on the distribution of dominant sweep rates and other properties of the detected chorus elements.

A sensitive and quantitative element-tagged immunoassay with ICPMS detection.

PubMed

Baranov, Vladimir I; Quinn, Zoë; Bandura, Dmitry R; Tanner, Scott D

2002-04-01

We report a set of novel immunoassays in which proteins of interest can be detected using specific element-tagged antibodies. These immunoassays are directly coupled with an inductively coupled plasma mass spectrometer (ICPMS) to quantify the elemental (in this work, metal) component of the reacted tagged antibodies. It is demonstrated that these methods can detect levels of target proteins as low as 0.1-0.5 ng/mL and yield a linear response to protein concentration over 3 orders of magnitude.

Apparatus and method using a holographic optical element for converting a spectral distribution to image points

NASA Technical Reports Server (NTRS)

McGill, Matthew J. (Inventor); Scott, Vibart S. (Inventor); Marzouk, Marzouk (Inventor)

2001-01-01

A holographic optical element transforms a spectral distribution of light to image points. The element comprises areas, each of which acts as a separate lens to image the light incident in its area to an image point. Each area contains the recorded hologram of a point source object. The image points can be made to lie in a line in the same focal plane so as to align with a linear array detector. A version of the element has been developed that has concentric equal areas to match the circular fringe pattern of a Fabry-Perot interferometer. The element has high transmission efficiency, and when coupled with high quantum efficiency solid state detectors, provides an efficient photon-collecting detection system. The element may be used as part of the detection system in a direct detection Doppler lidar system or multiple field of view lidar system.

Ion detection device and method with compressing ion-beam shutter

DOEpatents

Sperline, Roger P [Tucson, AZ

2009-05-26

An ion detection device, method and computer readable medium storing instructions for applying voltages to shutter elements of the detection device to compress ions in a volume defined by the shutter elements and to output the compressed ions to a collector. The ion detection device has a chamber having an inlet and receives ions through the inlet, a shutter provided in the chamber opposite the inlet and configured to allow or prevent the ions to pass the shutter, the shutter having first and second shutter elements, a collector provided in the chamber opposite the shutter and configured to collect ions passed through the shutter, and a processing unit electrically connected to the first and second shutter elements. The processing unit applies, during a first predetermined time interval, a first voltage to the first shutter element and a second voltage to the second shutter element, the second voltage being lower than the first voltage such that ions from the inlet enter a volume defined by the first and second shutter elements, and during a second predetermined time interval, a third voltage to the first shutter element, higher than the first voltage, and a fourth voltage to the second shutter element, the third voltage being higher than the fourth voltage such that ions that entered the volume are compressed as the ions exit the volume and new ions coming from the inlet are prevented from entering the volume. The processing unit is electrically connected to the collector and configured to detect the compressed ions based at least on a current received from the collector and produced by the ions collected by the collector.

A preliminary evaluation of a failure detection filter for detecting and identifying control element failures in a transport aircraft

NASA Technical Reports Server (NTRS)

Bundick, W. T.

1985-01-01

The application of the failure detection filter to the detection and identification of aircraft control element failures was evaluated in a linear digital simulation of the longitudinal dynamics of a B-737 Aircraft. Simulation results show that with a simple correlator and threshold detector used to process the filter residuals, the failure detection performance is seriously degraded by the effects of turbulence.

Sequential detection of web defects

DOEpatents

Eichel, Paul H.; Sleefe, Gerard E.; Stalker, K. Terry; Yee, Amy A.

2001-01-01

A system for detecting defects on a moving web having a sequential series of identical frames uses an imaging device to form a real-time camera image of a frame and a comparitor to comparing elements of the camera image with corresponding elements of an image of an exemplar frame. The comparitor provides an acceptable indication if the pair of elements are determined to be statistically identical; and a defective indication if the pair of elements are determined to be statistically not identical. If the pair of elements is neither acceptable nor defective, the comparitor recursively compares the element of said exemplar frame with corresponding elements of other frames on said web until one of the acceptable or defective indications occur.

Chemical sensor

NASA Technical Reports Server (NTRS)

Rauh, R. David (Inventor)

1990-01-01

A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

PAMELA/ATIC anomaly from the meta-stable extra dark matter component and the leptophilic Yukawa interaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kyae, Bumseok, E-mail: bkyae@phya.snu.ac.kr

We present a supersymmetric model with two dark matter (DM) components explaining the galactic positron excess observed by PAMELA/HEAT and ATIC/PPB-BETS: One is the conventional (bino-like) lightest supersymmetric particle (LSP) χ, and the other is a TeV scale meta-stable neutral singlet N{sub D}, which is a Dirac fermion (N,N{sup c}). In this model, N{sub D} decays dominantly into χe{sup +}e{sup −} through an R parity preserving dimension 6 operator with the life time τ{sub N} ∼ 10{sup 26} sec. We introduce a pair of vector-like superheavy SU(2) lepton doublets (L,L{sup c}) and lepton singlets (E,E{sup c}). The dimension 6 operatormore » leading to the N{sub D} decay is generated from the leptophilic Yukawa interactions by W superset of Ne{sup c}E+Lh{sub d}E{sup c}+m{sub 3/2}l{sub 1}L{sup c} with the dimensionless couplings of order unity, and the gauge interaction by L superset of (2){sup 1/2}g' e-tilde {sup c*}e{sup c}χ+h.c. The superheavy masses of the vector-like leptons (M{sub L},M{sub E} ∼ 10{sup 16} GeV) are responsible for the longevity of N{sub D}. The low energy field spectrum in this model is just the MSSM fields and N{sub D}. Even for the case that the portion of N{sub D} is much smaller than that of χ in the total DM density [O(10{sup −10}) ∼< n{sub N{sub D}}/n{sub χ}], the observed positron excess can be explained by adopting relatively lighter masses of the vector-like leptons (10{sup 13} GeV ∼< M{sub L,E} ∼< 10{sup 16} GeV). The smallness of the electron mass is also explained. This model is easily embedded in the flipped SU(5) grand unification, which is a leptophilic unified theory.« less

Method for detection of antibodies for metallic elements

DOEpatents

Barrick, C.W.; Clarke, S.M.; Nordin, C.W.

1993-11-30

An apparatus and method for detecting antibodies specific to non-protein antigens. The apparatus is an immunological plate containing a plurality of plastic projections coated with a non-protein material. Assays utilizing the plate are capable of stabilizing the non-protein antigens with detection levels for antibodies specific to the antigens on a nanogram level. A screening assay with the apparatus allows for early detection of exposure to non-protein materials. Specifically metallic elements are detected. 10 figures.

System and method for determination of the reflection wavelength of multiple low-reflectivity bragg gratings in a sensing optical fiber

NASA Technical Reports Server (NTRS)

Moore, Jason P. (Inventor)

2009-01-01

A system and method for determining a reflection wavelength of multiple Bragg gratings in a sensing optical fiber comprise: (1) a source laser; (2) an optical detector configured to detect a reflected signal from the sensing optical fiber; (3) a plurality of frequency generators configured to generate a signal having a frequency corresponding to an interferometer frequency of a different one of the plurality of Bragg gratings; (4) a plurality of demodulation elements, each demodulation element configured to combine the signal produced by a different one of the plurality of frequency generators with the detected signal from the sensing optical fiber; (5) a plurality of peak detectors, each peak detector configured to detect a peak of the combined signal from a different one of the demodulation elements; and (6) a laser wavenumber detection element configured to determine a wavenumber of the laser when any of the peak detectors detects a peak.

Bearing system

DOEpatents

Kapich, Davorin D.

1987-01-01

A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

Piezoelectric and Electrostatic Polymeric Transducers for Acoustic Emission Detection.

DTIC Science & Technology

1984-12-01

the fabrication of ultrasonic transducers for acoustic emission (A.E.) detection using polyvinylidene fluoride ( PVDF ) active elements. ii) the...characterization of PVDF transducers. The second report compared the sensitivity of PVDF transducers with polypropylene electrostatic transducer...detection using polyvinylidene 1uoride ( PVDF ) active elements. ii) the fabrication of electrostatic transducers using thin film of non-polar

Aerosol beam-focus laser-induced plasma spectrometer device

DOEpatents

Cheng, Meng-Dawn

2002-01-01

An apparatus for detecting elements in an aerosol includes an aerosol beam focuser for concentrating aerosol into an aerosol beam; a laser for directing a laser beam into the aerosol beam to form a plasma; a detection device that detects a wavelength of a light emission caused by the formation of the plasma. The detection device can be a spectrometer having at least one grating and a gated intensified charge-coupled device. The apparatus may also include a processor that correlates the wavelength of the light emission caused by the formation of the plasma with an identity of an element that corresponds to the wavelength. Furthermore, the apparatus can also include an aerosol generator for forming an aerosol beam from bulk materials. A method for detecting elements in an aerosol is also disclosed.

Detection of visible and latent fingerprints using micro-X-ray fluorescence elemental imaging.

PubMed

Worley, Christopher G; Wiltshire, Sara S; Miller, Thomasin C; Havrilla, George J; Majidi, Vahid

2006-01-01

Using micro-X-ray fluorescence (MXRF), a novel means of detecting fingerprints was examined in which the prints were imaged based on their elemental composition. MXRF is a nondestructive technique. Although this method requires a priori knowledge about the approximate location of a print, it offers a new and complementary means for detecting fingerprints that are also left pristine for further analysis (including potential DNA extraction) or archiving purposes. Sebaceous fingerprints and those made after perspiring were detected based on elements such as potassium and chlorine present in the print residue. Unique prints were also detected including those containing lotion, saliva, banana, or sunscreen. This proof-of-concept study demonstrates the potential for visualizing fingerprints by MXRF on surfaces that can be problematic using current methods.

Multiple-element semiquantitative analysis of one-milligram geochemical samples by D.C. arc emission spectrography

USGS Publications Warehouse

Rait, N.

1981-01-01

A modified method is described for a 1-mg sample multi-element semiquantitative spectrographic analysis. This method uses a direct-current arc source, carbon instead of graphite electrodes, and an 80% argon-20% oxygen atmosphere instead of air. Although this is a destructive method, an analysis can be made for 68 elements in all mineral and geochemical samples. Carbon electrodes have been an aid in improving the detection limits of many elements. The carbon has a greater resistance to heat conductance and develops a better tip, facilitating sample volatilization and counter balancing the cooling effect of a flow of the argon-oxygen mixture around the anode. Where such an argon-oxygen atmosphere is used instead of air, the cyanogen band lines are greatly diminished in intensity, and thus more spectral lines of analysis elements are available for use; the spectral background is also lower. The main advantage of using the carbon electrode and the 80% argon-20% oxygen atmosphere is the improved detection limits of 36 out of 68 elements. The detection limits remain the same for 23 elements, and are not as good for only nine elements. ?? 1981.

Uncertainties and understanding of experimental and theoretical results regarding reactions forming heavy and superheavy nuclei

NASA Astrophysics Data System (ADS)

Giardina, G.; Mandaglio, G.; Nasirov, A. K.; Anastasi, A.; Curciarello, F.; Fazio, G.

2018-02-01

Experimental and theoretical results of the PCN fusion probability of reactants in the entrance channel and the Wsur survival probability against fission at deexcitation of the compound nucleus formed in heavy-ion collisions are discussed. The theoretical results for a set of nuclear reactions leading to formation of compound nuclei (CNs) with the charge number Z = 102- 122 reveal a strong sensitivity of PCN to the characteristics of colliding nuclei in the entrance channel, dynamics of the reaction mechanism, and excitation energy of the system. We discuss the validity of assumptions and procedures for analysis of experimental data, and also the limits of validity of theoretical results obtained by the use of phenomenological models. The comparison of results obtained in many investigated reactions reveals serious limits of validity of the data analysis and calculation procedures.

α decay of high-K isomers in 270Ds and 266Hs in a superfluid tunneling model

NASA Astrophysics Data System (ADS)

Clark, R. M.; Rudolph, D.

2018-02-01

We use the superfluid tunneling model (STM) to calculate the half-lives of ground-state α decays of even-even superheavy nuclei (SHN) with Z ≥100 . The experimental data are reproduced to accuracies comparable to other contemporary models of α decay of SHN. We apply the STM to the case of the α decaying high-K isomers identified in the decay chains of 270Ds. By accounting for the α -decay Q values, Qα, the angular momentum difference between initial and final states, L, and a reduction in the pairing gap, Δ, we are able to reproduce the observed α decay of the isomers, including the unusual competition between L ≈10 and L ≈0 α branches seen for the K isomer in 270Ds(Z =110 ) .

Development of a Flexible Broadband Rayleigh Waves Comb Transducer with Nonequidistant Comb Interval for Defect Detection of Thick-Walled Pipelines

PubMed Central

He, Cunfu; Yan, Lyu; Zhang, Haijun

2018-01-01

It is necessary to develop a transducer that can quickly detect the inner and outer wall defects of thick-walled pipes, in order to ensure the safety of such pipes. In this paper, a flexible broadband Rayleigh-waves comb transducer based on PZT (lead zirconate titanate) for defect detection of thick-walled pipes is studied. The multiple resonant coupling theory is used to expand the transducer broadband and the FEA (Finite Element Analysis) method is used to optimize transducer array element parameters. Optimization results show that the best array element parameters of the transducer are when the transducer array element length is 30 mm, the thickness is 1.2 mm, the width of one end of is 1.5 mm, and the other end is 3 mm. Based on the optimization results, such a transducer was fabricated and its performance was tested. The test results were consistent with the finite-element simulation results, and the −3 dB bandwidth of the transducer reached 417 kHz. Transducer directivity test results show that the Θ−3dB beam width was equal to 10 °, to meet the defect detection requirements. Finally, defects of thick-walled pipes were detected using the transducer. The results showed that the transducer could detect the inner and outer wall defects of thick-walled pipes within the bandwidth. PMID:29498636

Development of a Flexible Broadband Rayleigh Waves Comb Transducer with Nonequidistant Comb Interval for Defect Detection of Thick-Walled Pipelines.

PubMed

Zhao, Huamin; He, Cunfu; Yan, Lyu; Zhang, Haijun

2018-03-02

It is necessary to develop a transducer that can quickly detect the inner and outer wall defects of thick-walled pipes, in order to ensure the safety of such pipes. In this paper, a flexible broadband Rayleigh-waves comb transducer based on PZT (lead zirconate titanate) for defect detection of thick-walled pipes is studied. The multiple resonant coupling theory is used to expand the transducer broadband and the FEA (Finite Element Analysis) method is used to optimize transducer array element parameters. Optimization results show that the best array element parameters of the transducer are when the transducer array element length is 30 mm, the thickness is 1.2 mm, the width of one end of is 1.5 mm, and the other end is 3 mm. Based on the optimization results, such a transducer was fabricated and its performance was tested. The test results were consistent with the finite-element simulation results, and the -3 dB bandwidth of the transducer reached 417 kHz. Transducer directivity test results show that the Θ -3dB beam width was equal to 10 °, to meet the defect detection requirements. Finally, defects of thick-walled pipes were detected using the transducer. The results showed that the transducer could detect the inner and outer wall defects of thick-walled pipes within the bandwidth.

Stochastic sensing through covalent interactions

DOEpatents

Bayley, Hagan; Shin, Seong-Ho; Luchian, Tudor; Cheley, Stephen

2013-03-26

A system and method for stochastic sensing in which the analyte covalently bonds to the sensor element or an adaptor element. If such bonding is irreversible, the bond may be broken by a chemical reagent. The sensor element may be a protein, such as the engineered P.sub.SH type or .alpha.HL protein pore. The analyte may be any reactive analyte, including chemical weapons, environmental toxins and pharmaceuticals. The analyte covalently bonds to the sensor element to produce a detectable signal. Possible signals include change in electrical current, change in force, and change in fluorescence. Detection of the signal allows identification of the analyte and determination of its concentration in a sample solution. Multiple analytes present in the same solution may be detected.

A new large solid angle multi-element silicon drift detector system for low energy X-ray fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Bufon, J.; Schillani, S.; Altissimo, M.; Bellutti, P.; Bertuccio, G.; Billè, F.; Borghes, R.; Borghi, G.; Cautero, G.; Cirrincione, D.; Fabiani, S.; Ficorella, F.; Gandola, M.; Gianoncelli, A.; Giuressi, D.; Kourousias, G.; Mele, F.; Menk, R. H.; Picciotto, A.; Rachevski, A.; Rashevskaya, I.; Sammartini, M.; Stolfa, A.; Zampa, G.; Zampa, N.; Zorzi, N.; Vacchi, A.

2018-03-01

Low-energy X-ray fluorescence (LEXRF) is an essential tool for bio-related research of organic samples, whose composition is dominated by light elements. Working at energies below 2 keV and being able to detect fluorescence photons of lightweight elements such as carbon (277 eV) is still a challenge, since it requires in-vacuum operations to avoid in-air photon absorption. Moreover, the detectors must have a thin entrance window and collect photons at an angle of incidence near 90 degrees to minimize the absorption by the protective coating. Considering the low fluorescence yield of light elements, it is important to cover a substantial part of the solid angle detecting ideally all emitted X-ray fluorescence (XRF) photons. Furthermore, the energy resolution of the detection system should be close to the Fano limit in order to discriminate elements whose XRF emission lines are often very close within the energy spectra. To ensure all these features, a system consisting of four monolithic multi-element silicon drift detectors was developed. The use of four separate detector units allows optimizing the incidence angle on all the sensor elements. The multi-element approach in turn provides a lower leakage current on each anode, which, in combination with ultra-low noise preamplifiers, is necessary to achieve an energy resolution close to the Fano limit. The potential of the new detection system and its applicability for typical LEXRF applications has been proved on the Elettra TwinMic beamline.

Infrared trace element detection system

DOEpatents

Bien, F.; Bernstein, L.S.; Matthew, M.W.

1988-11-15

An infrared trace element detection system includes an optical cell into which the sample fluid to be examined is introduced and removed. Also introduced into the optical cell is a sample beam of infrared radiation in a first wavelength band which is significantly absorbed by the trace element and a second wavelength band which is not significantly absorbed by the trace element for passage through the optical cell through the sample fluid. The output intensities of the sample beam of radiation are selectively detected in the first and second wavelength bands. The intensities of a reference beam of the radiation are similarly detected in the first and second wavelength bands. The sensed output intensity of the sample beam in one of the first and second wavelength bands is normalized with respect to the other and similarly, the intensity of the reference beam of radiation in one of the first and second wavelength bands is normalized with respect to the other. The normalized sample beam intensity and normalized reference beam intensity are then compared to provide a signal from which the amount of trace element in the sample fluid can be determined. 11 figs.

Infrared trace element detection system

DOEpatents

Bien, Fritz; Bernstein, Lawrence S.; Matthew, Michael W.

1988-01-01

An infrared trace element detection system including an optical cell into which the sample fluid to be examined is introduced and removed. Also introduced into the optical cell is a sample beam of infrared radiation in a first wavelength band which is significantly absorbed by the trace element and a second wavelength band which is not significantly absorbed by the trace element for passage through the optical cell through the sample fluid. The output intensities of the sample beam of radiation are selectively detected in the first and second wavelength bands. The intensities of a reference beam of the radiation are similarly detected in the first and second wavelength bands. The sensed output intensity of the sample beam in one of the first and second wavelength bands is normalized with respect to the other and similarly, the intensity of the reference beam of radiation in one of the first and second wavelength bands is normalized with respect to the other. The normalized sample beam intensity and normalized reference beam intensity are then compared to provide a signal from which the amount of trace element in the sample fluid can be determined.

A symmetric metamaterial element-based RF biosensor for rapid and label-free detection

NASA Astrophysics Data System (ADS)

Lee, Hee-Jo; Lee, Jung-Hyun; Jung, Hyo-Il

2011-10-01

A symmetric metamaterial element-based RF biosensing scheme is experimentally demonstrated by detecting biomolecular binding between a prostate-specific antigen (PSA) and its antibody. The metamaterial element in a high-impedance microstrip line shows an intrinsic S21 resonance having a Q-factor of 55. The frequency shift with PSA concentration, i.e., 100 ng/ml, 10 ng/ml, and 1 ng/ml, is observed and the changes are Δf ≈ 20 MHz, 10 MHz, and 5 MHz, respectively. The proposed biosensor offers advantages of label-free detection, a simple and direct scheme, and cost-efficient fabrication.

High throughput microcantilever detector

DOEpatents

Thundat, Thomas G.; Ferrell, Thomas L.; Hansen, Karolyn M.; Tian, Fang

2004-07-20

In an improved uncoated microcantilever detector, the sample sites are placed on a separate semi-conducting substrate and the microcantilever element detects and measures the changes before and after a chemical interaction or hybridization of the sites by sensing differences of phase angle between an alternating voltage applied to the microcantilever element and vibration of the microcantilever element. In another embodiment of the invention, multiple sample sites are on a sample array wherein an array of microcantilever elements detect and measure the change before and after chemical interactions or hybridizations of the sample sites.

Development of a morphological convolution operator for bearing fault detection

NASA Astrophysics Data System (ADS)

Li, Yifan; Liang, Xihui; Liu, Weiwei; Wang, Yan

2018-05-01

This paper presents a novel signal processing scheme, namely morphological convolution operator (MCO) lifted morphological undecimated wavelet (MUDW), for rolling element bearing fault detection. In this scheme, a MCO is first designed to fully utilize the advantage of the closing & opening gradient operator and the closing-opening & opening-closing gradient operator for feature extraction as well as the merit of excellent denoising characteristics of the convolution operator. The MCO is then introduced into MUDW for the purpose of improving the fault detection ability of the reported MUDWs. Experimental vibration signals collected from a train wheelset test rig and the bearing data center of Case Western Reserve University are employed to evaluate the effectiveness of the proposed MCO lifted MUDW on fault detection of rolling element bearings. The results show that the proposed approach has a superior performance in extracting fault features of defective rolling element bearings. In addition, comparisons are performed between two reported MUDWs and the proposed MCO lifted MUDW. The MCO lifted MUDW outperforms both of them in detection of outer race faults and inner race faults of rolling element bearings.

Neutron detector

DOEpatents

Stephan, Andrew C [Knoxville, TN; Jardret,; Vincent, D [Powell, TN

2011-04-05

A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

Improving prokaryotic transposable elements identification using a combination of de novo and profile HMM methods.

PubMed

Kamoun, Choumouss; Payen, Thibaut; Hua-Van, Aurélie; Filée, Jonathan

2013-10-11

Insertion Sequences (ISs) and their non-autonomous derivatives (MITEs) are important components of prokaryotic genomes inducing duplication, deletion, rearrangement or lateral gene transfers. Although ISs and MITEs are relatively simple and basic genetic elements, their detection remains a difficult task due to their remarkable sequence diversity. With the advent of high-throughput genome and metagenome sequencing technologies, the development of fast, reliable and sensitive methods of ISs and MITEs detection become an important challenge. So far, almost all studies dealing with prokaryotic transposons have used classical BLAST-based detection methods against reference libraries. Here we introduce alternative methods of detection either taking advantages of the structural properties of the elements (de novo methods) or using an additional library-based method using profile HMM searches. In this study, we have developed three different work flows dedicated to ISs and MITEs detection: the first two use de novo methods detecting either repeated sequences or presence of Inverted Repeats; the third one use 28 in-house transposase alignment profiles with HMM search methods. We have compared the respective performances of each method using a reference dataset of 30 archaeal and 30 bacterial genomes in addition to simulated and real metagenomes. Compared to a BLAST-based method using ISFinder as library, de novo methods significantly improve ISs and MITEs detection. For example, in the 30 archaeal genomes, we discovered 30 new elements (+20%) in addition to the 141 multi-copies elements already detected by the BLAST approach. Many of the new elements correspond to ISs belonging to unknown or highly divergent families. The total number of MITEs has even doubled with the discovery of elements displaying very limited sequence similarities with their respective autonomous partners (mainly in the Inverted Repeats of the elements). Concerning metagenomes, with the exception of short reads data (<300 bp) for which both techniques seem equally limited, profile HMM searches considerably ameliorate the detection of transposase encoding genes (up to +50%) generating low level of false positives compare to BLAST-based methods. Compared to classical BLAST-based methods, the sensitivity of de novo and profile HMM methods developed in this study allow a better and more reliable detection of transposons in prokaryotic genomes and metagenomes. We believed that future studies implying ISs and MITEs identification in genomic data should combine at least one de novo and one library-based method, with optimal results obtained by running the two de novo methods in addition to a library-based search. For metagenomic data, profile HMM search should be favored, a BLAST-based step is only useful to the final annotation into groups and families.

Diagnostic use of computational retrotransposon detection: Successful definition of pathogenetic mechanism in a ciliopathy phenotype.

PubMed

Takenouchi, Toshiki; Kuchikata, Tomu; Yoshihashi, Hiroshi; Fujiwara, Mineko; Uehara, Tomoko; Miyama, Sahoko; Yamada, Shiro; Kosaki, Kenjiro

2017-05-01

Among more than 5,000 human monogenic disorders with known causative genes, transposable element insertion of a Long Interspersed Nuclear Element 1 (LINE1, L1) is known as the mechanistic basis in only 13 genetic conditions. Meckel-Gruber syndrome is a rare ciliopathy characterized by occipital encephalocele and cystic kidney disease. Here, we document a boy with occipital encephalocele, post-axial polydactyly, and multicystic renal disease. A medical exome analysis detected a heterozygous frameshift mutation, c.4582_4583delCG p.(Arg1528Serfs*17) in CC2D2A in the maternally derived allele. The further use of a dedicated bioinformatics algorithm for detecting retrotransposon insertions led to the detection of an L1 insertion affecting exon 7 in the paternally derived allele. The complete sequencing and sequence homology analysis of the inserted L1 element showed that the L1 element was classified as L1HS (L1 human specific) and that the element had intact open reading frames in the two L1-encoded proteins. This observation ranks Meckel-Gruber syndrome as only the 14th disorder to be caused by an L1 insertion among more than 5,000 known human genetic disorders. Although a transposable element detection algorithm is not included in the current best-practice next-generation sequencing analysis, the present observation illustrates the utility of such an algorithm, which would require modest computational time and resources. Whether the seemingly infrequent recognition of L1 insertion in the pathogenesis of human genetic diseases might simply reflect a lack of appropriate detection methods remains to be seen. © 2017 Wiley Periodicals, Inc.

Optimizing detector geometry for trace element mapping by X-ray fluorescence.

PubMed

Sun, Yue; Gleber, Sophie-Charlotte; Jacobsen, Chris; Kirz, Janos; Vogt, Stefan

2015-05-01

Trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral response of energy dispersive detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. We conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples. Copyright © 2015. Published by Elsevier B.V.

Optimizing detector geometry for trace element mapping by X-ray fluorescence

PubMed Central

Sun, Yue; Gleber, Sophie-Charlotte; Jacobsen, Chris; Kirz, Janos; Vogt, Stefan

2016-01-01

Trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral response of energy dispersive detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. We conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples. PMID:25600825

Optimizing detector geometry for trace element mapping by X-ray fluorescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Yue; Gleber, Sophie-Charlotte; Jacobsen, Chris

Trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral response of energy dispersivemore » detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. We conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples.« less

Concentrations of Elements in Sediments and Selective Fractions of Sediments, and in Natural Waters in Contact with Sediments from Lake Roosevelt, Washington, September 2004

USGS Publications Warehouse

Paulson, Anthony J.; Wagner, Richard J.; Sanzolone, Richard F.; Cox, Steven E.

2006-01-01

Twenty-eight composite and replicate sediment samples from 8 Lake Roosevelt sites were collected and analyzed for 10 alkali and alkaline earth elements, 2 non-metals, 20 metals, and 4 lanthanide and actinide elements. All elements were detected in all sediment samples except for silver (95 percent of the elements detected for 1,008 analyses), which was detected only in 4 samples. Sequential selective extraction procedures were performed on single composite samples from the eight sites. The percentage of detections for the 31 elements analyzed ranged from 76 percent for the first extraction fraction using a weak extractant to 93 percent for the four-acid dissolution of the sediments remaining after the third sequential selective extraction. Water samples in various degrees of contact with the sediment were analyzed for 10 alkali and alkaline earth elements, 5 non-metals, 25 metals, and 16 lanthanide and actinide elements. The filtered water samples included 10 samples from the reservoir water column at 8 sites, 32 samples of porewater, 55 samples from reservoir water overlying sediments in 8 cores from the site incubated in a field laboratory, and 24 water samples that were filtered after being tumbled with sediments from 8 sites. Overall, the concentrations of only 37 percent of the 6,776 analyses of the 121 water samples were greater than the reporting limit. Selenium, bismuth, chromium, niobium, silver, and zirconium were not detected in any water samples. The percentage of concentrations for the water samples that were above the reporting limit ranged from 14 percent for the lanthanide and actinide elements to 77 percent for the alkali and alkaline earth elements. Concentrations were greater than reporting limits in only 23 percent of the analyses of reservoir water and 29 percent of the analyses of reservoir water overlying incubation cores. In contrast, 47 and 48 percent of the concentrations of porewater and water samples tumbled with sediments, respectively, were greater than the reporting limit.

Characterization of the quality of water, bed sediment, and fish in Mittry Lake, Arizona, 2014–15

USGS Publications Warehouse

Hermosillo, Edyth; Coes, Alissa L.

2017-03-01

Water, bed-sediment, and fish sampling was conducted in Mittry Lake, Arizona, in 2014–15 to establish current water-quality conditions of the lake. The parameters of temperature, dissolved-oxygen concentration, specific conductance, and alkalinity were measured in the field. Water samples were collected and analyzed for dissolved major ions, dissolved trace elements, dissolved nutrients, dissolved organic carbon, dissolved pesticides, bacteria, and suspended-sediment concentrations. Bed-sediment and fish samples were analyzed for trace elements, halogenated compounds, total mercury, and methylmercury.U.S. Environmental Protection Agency secondary maximum contaminant levels in drinking water were exceeded for sulfate, chloride, and manganese in the water samples. Trace-element concentrations were relatively similar between the inlet, middle, and outlet locations. Concentrations for nutrients in all water samples were below the Arizona Department of Environmental Quality’s water-quality standards for aquatic and wildlife uses, and all bacteria levels were below the Arizona Department of Environmental Quality’s recommended recreational water-quality criteria. Three out of 81 pesticides were detected in the water samples.Trace-element concentrations in bed sediment were relatively consistent between the inlet, middle, and outlet locations. Lead, manganese, nickel, and zinc concentrations, however, decreased from the inlet to outlet locations. Concentrations for lead, nickel, and zinc in some bed-sediment samples exceeded consensus-based sediment-quality guidelines probable effect concentrations. Eleven out of 61 halogenated compounds were detected in bed sediment at the inlet location, whereas three were detected at the middle location, and five were detected at the outlet location. No methylmercury was detected in bed sediment. Total mercury was detected in bed sediment at concentrations below the consensus-based sediment-quality guidelines probable effect concentration.Sixteen trace elements were detected in at least one of the fish-tissue samples, and trace-element concentrations were relatively consistent between the three fish-tissue samples. Seven halogenated compounds were detected in at least one of the whole-body fish samples; four to five compounds were detected in each fish. One fish-tissue sample exceeded the U.S. Environmental Protection Agency human health consumption criteria for methylmercury.

The role of off-line mass spectrometry in nuclear fission.

PubMed

De Laeter, J R

1996-01-01

The role of mass spectrometry in nuclear fission has been invaluable since 1940, when A. O. C. Nier separated microgram quantities of (235) U from (238) U, using a gas source mass spectrometer. This experiment enabled the fissionable nature of (235) U to be established. During the Manhattan Project, the mass spectrometer was used to measure the isotope abundances of uranium after processing in various separation systems, in monitoring the composition of the gaseous products in the Oak Ridge Diffusion Plant, and as a helium leak detector. Following the construction of the first reactor at the University of Chicago, it was necessary to unravel the nuclear systematics of the various fission products produced in the fission process. Off-line mass spectrometry was able to identify stable and long-lived isotopes produced in fission, but more importantly, was used in numerous studies of the distribution of mass of the cumulative fission yields. Improvements in sensitivity enabled off-line mass spectrometric studies to identify fine structure in the mass-yield curve and, hence, demonstrate the importance of shell structure in nuclear fission. Solid-source mass spectrometry was also able to measure the cumulative fission yields in the valley of symmetry in the mass-yield curve, and enabled spontaneous fission yields to be quantified. Apart from the accurate measurement of abundances, the stable isotope mass spectrometric technique has been invaluable in establishing absolute cumulative fission yields for many isotopes making up the mass-yield distribution curve for a variety of fissile nuclides. Extensive mass spectrometric studies of noble gases in primitive meteorites revealed the presence of fission products from the now extinct nuclide (244) Pu, and have eliminated the possibility of fission products from a super-heavy nuclide contributing to isotopic anomalies in meteoritic material. Numerous mass spectrometric studies of the isotopic and elemental abundances of samples from the Oklo Natural Reactor have enabled the nuclear parameters of the various reactor zones to be calculated, and the mobility/retentivity of a number of elements to be established in the reactor zones and the surrounding rocks. These isotopic studies have given valuable information on the geochemical behavior of natural geological repositories for radioactive waste containment. © 1997 John Wiley & Sons, Inc. Copyright © 1997 John Wiley & Sons, Inc.

Conductometric Sensors for Detection of Elemental Mercury Vapor

NASA Technical Reports Server (NTRS)

Ryan, M. A.; Homer, M. L.; Shevade, A. V.; Lara, L. M.; Yen, S.-P. S.; Kisor, A. K.; Manatt, K. S.

2008-01-01

Several organic and inorganic materials have been tested for possible incorporation into a sensing array in order to add elemental mercury vapor to the suite of chemical species detected. Materials have included gold films, treated gold films, polymer-carbon composite films, gold-polymer-carbon composite films and palladium chloride sintered films. The toxicity of mercury and its adverse effect on human and animal health has made environmental monitoring of mercury in gas and liquid phases important (1,2). As consumer products which contain elemental mercury, such as fluorescent lighting, become more widespread, the need to monitor environments for the presence of vapor phase elemental mercury will increase. Sensors in use today to detect mercury in gaseous streams are generally based on amalgam formation with gold or other metals, including noble metals and aluminum. Recently, NASA has recognized a need to detect elemental mercury vapor in the breathing atmosphere of the crew cabin in spacecraft and has requested that such a capability be incorporated into the JPL Electronic Nose (3). The detection concentration target for this application is 10 parts-per-billion (ppb), or 0.08 mg/m3. In order to respond to the request to incorporate mercury sensing into the JPL Electronic Nose (ENose) platform, it was necessary to consider only conductometric methods of sensing, as any other transduction method would have required redesign of the platform. Any mercury detection technique which could not be incorporated into the existing platform, such as an electrochemical technique, could not be considered.

Improved detection sensitivity of γ-aminobutyric acid based on graphene oxide interface on an optical microfiber.

PubMed

Zhou, Jun; Huang, Yunyun; Chen, Chaoyan; Xiao, Aoxiang; Guo, Tuan; Guan, Bai-Ou

2018-05-11

Interfacing bio-recognition elements to optical materials is a longstanding challenge to manufacture sensitive biosensors and inexpensive diagnostic devices. In this work, a graphene oxide (GO) interface has been constructed between silica microfiber and bio-recognition elements to develop an improved γ-aminobutyric acid (GABA) sensing approach. The GO interface, which was located at the site with the strongest evanescent field on the microfiber surface, improved the detection sensitivity by providing a larger platform for more bio-recognition element immobilization, and amplifying surface refractive index change caused by combination between bio-recognition elements and target molecules. Owing to the interface improvement, the microfiber has a three times improved sensitivity of 1.03 nm/log M for GABA detection, and hence a lowest limit of detection of 2.91 × 10-18 M, which is 7 orders of magnitude higher than that without the GO interface. Moreover, the micrometer-sized footprint and non-radioactive nature enable easy implantation in human brains for in vivo applications.

Persistent organic pollutants and inorganic elements in the Balearic shearwater Puffinus mauretanicus wintering off Portugal.

PubMed

Costa, R A; Torres, J; Vingada, J V; Eira, C

2016-07-15

This study presents the first data on trace element and organic pollutant concentrations in the Critically Endangered Balearic shearwater Puffinus mauretanicus collected in 2010 and 2011 in Portugal. Trace element levels were below the threshold levels for adverse effects on birds, despite the Hg concentrations in feathers (4.35μg·g-1ww). No significant differences were detected between individuals from 2010 and 2011 except for Se concentrations in liver, feathers and muscle (higher in 2010) and Ag in liver and muscle (higher in 2011). No significant differences were detected in total concentrations of organochlorine compounds in Balearic shearwaters between years, although PCB congeners -101 and -180 presented higher concentrations in individuals from 2010. The PCB congeners -138, -153 and -180, and 4.4-DDE were detected in all individuals. This study on toxic elements and organic pollutants in wintering Balearic shearwaters provides baseline data from which deviations can be detected in the future. Copyright © 2016 Elsevier Ltd. All rights reserved.

Method and an apparatus for non-invasively determining the quantity of an element in a body organ

DOEpatents

Vartsky, D.; Ellis, K.J.; Cohn, S.H.

1980-06-27

An apparatus and a method for determining in a body organ the amount of an element with the aid of a gaseous gamma ray source, where the element and the source are paired in predetermined pairs, and with the aid of at least one detector selected from the group consisting of Ge(Li) and NaI(Tl). Gamma rays are directed towards the organ, thereby resonantly scattering the gamma rays from nuclei of the element in the organ; the intensity of the gamma rays is detected by the detector; and the amount of the element in the organ is then substantially proportional to the detected intensity of the gamma rays.

Incipient Fault Detection for Rolling Element Bearings under Varying Speed Conditions.

PubMed

Xue, Lang; Li, Naipeng; Lei, Yaguo; Li, Ningbo

2017-06-20

Varying speed conditions bring a huge challenge to incipient fault detection of rolling element bearings because both the change of speed and faults could lead to the amplitude fluctuation of vibration signals. Effective detection methods need to be developed to eliminate the influence of speed variation. This paper proposes an incipient fault detection method for bearings under varying speed conditions. Firstly, relative residual (RR) features are extracted, which are insensitive to the varying speed conditions and are able to reflect the degradation trend of bearings. Then, a health indicator named selected negative log-likelihood probability (SNLLP) is constructed to fuse a feature set including RR features and non-dimensional features. Finally, based on the constructed SNLLP health indicator, a novel alarm trigger mechanism is designed to detect the incipient fault. The proposed method is demonstrated using vibration signals from bearing tests and industrial wind turbines. The results verify the effectiveness of the proposed method for incipient fault detection of rolling element bearings under varying speed conditions.

Incipient Fault Detection for Rolling Element Bearings under Varying Speed Conditions

PubMed Central

Xue, Lang; Li, Naipeng; Lei, Yaguo; Li, Ningbo

2017-01-01

Varying speed conditions bring a huge challenge to incipient fault detection of rolling element bearings because both the change of speed and faults could lead to the amplitude fluctuation of vibration signals. Effective detection methods need to be developed to eliminate the influence of speed variation. This paper proposes an incipient fault detection method for bearings under varying speed conditions. Firstly, relative residual (RR) features are extracted, which are insensitive to the varying speed conditions and are able to reflect the degradation trend of bearings. Then, a health indicator named selected negative log-likelihood probability (SNLLP) is constructed to fuse a feature set including RR features and non-dimensional features. Finally, based on the constructed SNLLP health indicator, a novel alarm trigger mechanism is designed to detect the incipient fault. The proposed method is demonstrated using vibration signals from bearing tests and industrial wind turbines. The results verify the effectiveness of the proposed method for incipient fault detection of rolling element bearings under varying speed conditions. PMID:28773035

Laser spectrum detection methods for substance of Mars surface

NASA Astrophysics Data System (ADS)

Zhang, Dan; Xue, Bin; Zhao, Yi-yi

2014-11-01

The chemical element and mineral rock's abundance and distribution are the basic material of planetary geology evolution research [1], hence preterit detection for composition of Mars surface substance contains both elements sorts and mineral ingredients. This article introduced new ways to detect Mars elements and mineral components, Laser Induced Breakdown Spectroscopy (LIBS) and Raman Spectroscopy (RS) which have distinct advantages, such as work over a long distance, detect rapidly, accuratly and nondestructively. LIBS and RS both use laser excitation to shoot the substance of Mars exciting new wavelengths. The techniques of LIBS and RS in laboratory are mature, besides the technique of LIBS is being used in MSL (Chemcam) now and RS will be used in ExoMars. Comparing LIBS and RS's detection results with XRF and APXS, Mossbauer spectrometer, these existed Mars surface material detection instruments,and the Infrared spectrometer, Mid-IR, they have more accurate detection results. So LIBS and RS are competent for Mars surface substance detection instead of X-ray spectrometer and Mossbauer spectrometer which were already used in 'Viking 1' and 'Opportunity'. Only accurate detection results about Mars surface substance can lead to scientist's right analysis in inversing geological evolution of the planet.

Semiconductor radiation detector

DOEpatents

Bell, Zane W.; Burger, Arnold

2010-03-30

A semiconductor detector for ionizing electromagnetic radiation, neutrons, and energetic charged particles. The detecting element is comprised of a compound having the composition I-III-VI.sub.2 or II-IV-V.sub.2 where the "I" component is from column 1A or 1B of the periodic table, the "II" component is from column 2B, the "III" component is from column 3A, the "IV" component is from column 4A, the "V" component is from column 5A, and the "VI" component is from column 6A. The detecting element detects ionizing radiation by generating a signal proportional to the energy deposited in the element, and detects neutrons by virtue of the ionizing radiation emitted by one or more of the constituent materials subsequent to capture. The detector may contain more than one neutron-sensitive component.

Delamination Defect Detection Using Ultrasonic Guided Waves in Advanced Hybrid Structural Elements

NASA Astrophysics Data System (ADS)

Yan, Fei; Qi, Kevin ``Xue''; Rose, Joseph L.; Weiland, Hasso

2010-02-01

Nondestructive testing for multilayered structures is challenging because of increased numbers of layers and plate thicknesses. In this paper, ultrasonic guided waves are applied to detect delamination defects inside a 23-layer Alcoa Advanced Hybrid Structural plate. A semi-analytical finite element (SAFE) method generates dispersion curves and wave structures in order to select appropriate wave structures to detect certain defects. One guided wave mode and frequency is chosen to achieve large in-plane displacements at regions of interest. The interactions of the selected mode with defects are simulated using finite element models. Experiments are conducted and compared with bulk wave measurements. It is shown that guided waves can detect deeply embedded damages inside thick multilayer fiber-metal laminates with suitable mode and frequency selection.

Sensor and methods of detecting target materials and situations in closed systems

DOEpatents

Mee, David K.; Ripley, Edward B.; Nienstedt, Zachary C.; Nienstedt, Alex W.; Howell, Jr., Layton N.

2018-03-13

Disclosed is a passive, in-situ pressure sensor. The sensor includes a sensing element having a ferromagnetic metal and a tension inducing mechanism coupled to the ferromagnetic metal. The tension inducing mechanism is operable to change a tensile stress upon the ferromagnetic metal based on a change in pressure in the sensing element. Changes in pressure are detected based on changes in the magnetic switching characteristics of the ferromagnetic metal when subjected to an alternating magnetic field caused by the change in the tensile stress. The sensing element is embeddable in a closed system for detecting pressure changes without the need for any penetrations of the system for power or data acquisition by detecting changes in the magnetic switching characteristics of the ferromagnetic metal caused by the tensile stress.

Change Point Detection in Correlation Networks

NASA Astrophysics Data System (ADS)

Barnett, Ian; Onnela, Jukka-Pekka

2016-01-01

Many systems of interacting elements can be conceptualized as networks, where network nodes represent the elements and network ties represent interactions between the elements. In systems where the underlying network evolves, it is useful to determine the points in time where the network structure changes significantly as these may correspond to functional change points. We propose a method for detecting change points in correlation networks that, unlike previous change point detection methods designed for time series data, requires minimal distributional assumptions. We investigate the difficulty of change point detection near the boundaries of the time series in correlation networks and study the power of our method and competing methods through simulation. We also show the generalizable nature of the method by applying it to stock price data as well as fMRI data.

An x ray scatter approach for non-destructive chemical analysis of low atomic numbered elements

NASA Technical Reports Server (NTRS)

Ross, H. Richard

1993-01-01

A non-destructive x-ray scatter (XRS) approach has been developed, along with a rapid atomic scatter algorithm for the detection and analysis of low atomic-numbered elements in solids, powders, and liquids. The present method of energy dispersive x-ray fluorescence spectroscopy (EDXRF) makes the analysis of light elements (i.e., less than sodium; less than 11) extremely difficult. Detection and measurement become progressively worse as atomic numbers become smaller, due to a competing process called 'Auger Emission', which reduces fluorescent intensity, coupled with the high mass absorption coefficients exhibited by low energy x-rays, the detection and determination of low atomic-numbered elements by x-ray spectrometry is limited. However, an indirect approach based on the intensity ratio of Compton and Rayleigh scattered has been used to define light element components in alloys, plastics and other materials. This XRS technique provides qualitative and quantitative information about the overall constituents of a variety of samples.

Electrostatically tunable resonance frequency beam utilizing a stress-sensitive film

DOEpatents

Thundat, Thomas G.; Wachter, Eric A.; Davis, J. Kenneth

2001-01-01

Methods and apparatus for detecting particular frequencies of acoustic vibration utilize an electrostatically-tunable beam element having a stress-sensitive coating and means for providing electrostatic force to controllably deflect the beam element thereby changing its stiffness and its resonance frequency. It is then determined from the response of the electrostatically-tunable beam element to the acoustical vibration to which the beam is exposed whether or not a particular frequency or frequencies of acoustic vibration are detected.

Magnetically tunable resonance frequency beam utilizing a stress-sensitive film

DOEpatents

Davis, J. Kenneth; Thundat, Thomas G.; Wachter, Eric A.

2001-01-01

Methods and apparatus for detecting particular frequencies of vibration utilize a magnetically-tunable beam element having a stress-sensitive coating and means for providing magnetic force to controllably deflect the beam element thereby changing its stiffness and its resonance frequency. It is then determined from the response of the magnetically-tunable beam element to the vibration to which the beam is exposed whether or not a particular frequency or frequencies of vibration are detected.

Scanning Electron Microscope-Cathodoluminescence Analysis of Rare-Earth Elements in Magnets.

PubMed

Imashuku, Susumu; Wagatsuma, Kazuaki; Kawai, Jun

2016-02-01

Scanning electron microscope-cathodoluminescence (SEM-CL) analysis was performed for neodymium-iron-boron (NdFeB) and samarium-cobalt (Sm-Co) magnets to analyze the rare-earth elements present in the magnets. We examined the advantages of SEM-CL analysis over conventional analytical methods such as SEM-energy-dispersive X-ray (EDX) spectroscopy and SEM-wavelength-dispersive X-ray (WDX) spectroscopy for elemental analysis of rare-earth elements in NdFeB magnets. Luminescence spectra of chloride compounds of elements in the magnets were measured by the SEM-CL method. Chloride compounds were obtained by the dropwise addition of hydrochloric acid on the magnets followed by drying in vacuum. Neodymium, praseodymium, terbium, and dysprosium were separately detected in the NdFeB magnets, and samarium was detected in the Sm-Co magnet by the SEM-CL method. In contrast, it was difficult to distinguish terbium and dysprosium in the NdFeB magnet with a dysprosium concentration of 1.05 wt% by conventional SEM-EDX analysis. Terbium with a concentration of 0.02 wt% in an NdFeB magnet was detected by SEM-CL analysis, but not by conventional SEM-WDX analysis. SEM-CL analysis is advantageous over conventional SEM-EDX and SEM-WDX analyses for detecting trace rare-earth elements in NdFeB magnets, particularly dysprosium and terbium.

Hiding an elephant: heavy sterile neutrino with large mixing angle does not contradict cosmology

NASA Astrophysics Data System (ADS)

Bezrukov, F.; Chudaykin, A.; Gorbunov, D.

2017-06-01

We study a model of a keV-scale sterile neutrino with a relatively large mixing with the Standard Model sector. Usual considerations predict active generation of such particles in the early Universe, which leads to constraints from the total Dark Matter density and absence of X-ray signal from sterile neutrino decay. These bounds together may deem any attempt of creation of the keV scale sterile neutrino in the laboratory unfeasible. We argue that for models with a hidden sector coupled to the sterile neutrino these bounds can be evaded, opening new perspectives for the direct studies at neutrino experiments such as Troitsk ν-mass and KATRIN. We estimate the generation of sterile neutrinos in scenarios with the hidden sector dynamics keeping the sterile neutrinos either massless or superheavy in the early Universe. In both cases the generation by oscillations from active neutrinos in plasma is suppressed.

Problems with the sources of the observed gravitational waves and their resolution

NASA Astrophysics Data System (ADS)

Dolgov, A. D.

2017-04-01

Recent direct registration of gravitational waves by LIGO and astronomical observations of the universe at redshifts 5-10 demonstrate that the standard astrophysics and cosmology are in tension with the data. The origin of the source of the GW150914 event, which presumably is a binary of coalescing black holes with masses about 30 solar masses, each with zero spin, as well as the densely populated universe at z= 5-10 by superheavy black holes, blight galaxies, supernovae, and dust does not fit the standard astrophysical picture. It is shown here that the model of primordial black hole (PBH) formation, suggested in 1993, nicely explains all these and more puzzles, including those in contemporary universe, such as MACHOs and the mass spectrum of the observed solar mass black holes.. The mass spectrum and density of PBH is predicted. The scenario may possibly lead to abundant antimatter in the universe and even in the Galaxy.

Maximum efficiency of the collisional Penrose process

NASA Astrophysics Data System (ADS)

Zaslavskii, O. B.

2016-09-01

We consider the collision of two particles that move in the equatorial plane near a general stationary rotating axially symmetric extremal black hole. One of the particles is critical (with fine-tuned parameters) and moves in the outward direction. The second particle (usual, not fine-tuned) comes from infinity. We examine the efficiency η of the collisional Penrose process. There are two relevant cases here: a particle falling into a black hole after collision (i) is heavy or (ii) has a finite mass. We show that the maximum of η in case (ii) is less than or equal to that in case (i). It is argued that for superheavy particles, the bound applies to nonequatorial motion as well. As an example, we analyze collision in the Kerr-Newman background. When the bound is the same for processes (i) and (ii), η =3 for this metric. For the Kerr black hole, recent results in the literature are reproduced.

Fission barriers from multidimensionally-constrained covariant density functional theories

NASA Astrophysics Data System (ADS)

Lu, Bing-Nan; Zhao, Jie; Zhao, En-Guang; Zhou, Shan-Gui

2017-11-01

In recent years, we have developed the multidimensionally-constrained covariant density functional theories (MDC-CDFTs) in which both axial and spatial reflection symmetries are broken and all shape degrees of freedom described by βλμ with even μ, such as β20, β22, β30, β32, β40, etc., are included self-consistently. The MDC-CDFTs have been applied to the investigation of potential energy surfaces and fission barriers of actinide nuclei, third minima in potential energy surfaces of light actinides, shapes and potential energy surfaces of superheavy nuclei, octupole correlations between multiple chiral doublet bands in 78Br, octupole correlations in Ba isotopes, the Y32 correlations in N = 150 isotones and Zr isotopes, the spontaneous fission of Fm isotopes, and shapes of hypernuclei. In this contribution we present the formalism of MDC-CDFTs and the application of these theories to the study of fission barriers and potential energy surfaces of actinide nuclei.

Universal charge-radius relation for subatomic and astrophysical compact objects.

PubMed

Madsen, Jes

2008-04-18

Electron-positron pair creation in supercritical electric fields limits the net charge of any static, spherical object, such as superheavy nuclei, strangelets, and Q balls, or compact stars like neutron stars, quark stars, and black holes. For radii between 4 x 10(2) and 10(4) fm the upper bound on the net charge is given by the universal relation Z=0.71R(fm), and for larger radii (measured in femtometers or kilometers) Z=7 x 10(-5)R_(2)(fm)=7 x 10(31)R_(2)(km). For objects with nuclear density the relation corresponds to Z approximately 0.7A(1/3)( (10(8)10(12)), where A is the baryon number. For some systems this universal upper bound improves existing charge limits in the literature.

Dynamical approach to fusion-fission process in superheavy mass region

NASA Astrophysics Data System (ADS)

Aritomo, Y.; Hinde, D. J.; Wakhle, A.; du Rietz, R.; Dasgupta, M.; Hagino, K.; Chiba, S.; Nishio, K.

2012-10-01

In order to describe heavy-ion fusion reactions around the Coulomb barrier with an actinide target nucleus, we propose a model which combines the coupled-channels approach and a fluctuation-dissipation model for dynamical calculations. This model takes into account couplings to the collective states of the interacting nuclei in the penetration of the Coulomb barrier and the subsequent dynamical evolution of a nuclear shape from the contact configuration. In the fluctuation-dissipation model with a Langevin equation, the effect of nuclear orientation at the initial impact on the prolately deformed target nucleus is considered. Fusion-fission, quasifission and deep quasifission are separated as different Langevin trajectories on the potential energy surface. Using this model, we analyze the experimental data for the mass distribution of fission fragments (MDFF) in the reaction of 36S+238U at several incident energies around the Coulomb barrier.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Esmaili, Arman; Peres, Orlando L.G.; Ibarra, Alejandro, E-mail: aesmaili@ifi.unicamp.br, E-mail: ibarra@tum.de, E-mail: orlando@ifi.unicamp.br

2012-11-01

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 in this paper lower limits on the lifetime of dark matter particles with masses in the range 10TeV−10{sup 15}TeV from the non-observation of ultrahigh energy neutrinos in the AMANDA, IceCube, Auger and ANITA experiments. For dark matter particles which produce neutrinos in a two body or a three body leptonic decay, we find that the dark matter lifetime must be longer than O(10{sup 26}−10{sup 28})s for masses between 10more » TeV and the Grand Unification scale. Finally, we also calculate, for concrete particle physics scenarios, the limits on the strength of the interactions that induce the dark matter decay.« less

Nitrogen dioxide detection

DOEpatents

Sinha, Dipen N.; Agnew, Stephen F.; Christensen, William H.

1993-01-01

Method and apparatus for detecting the presence of gaseous nitrogen dioxide and determining the amount of gas which is present. Though polystyrene is normally an insulator, it becomes electrically conductive in the presence of nitrogen dioxide. Conductance or resistance of a polystyrene sensing element is related to the concentration of nitrogen dioxide at the sensing element.

Micromechanical potentiometric sensors

DOEpatents

Thundat, Thomas G.

2000-01-01

A microcantilever potentiometric sensor utilized for detecting and measuring physical and chemical parameters in a sample of media is described. The microcantilevered spring element includes at least one chemical coating on a coated region, that accumulates a surface charge in response to hydrogen ions, redox potential, or ion concentrations in a sample of the media being monitored. The accumulation of surface charge on one surface of the microcantilever, with a differing surface charge on an opposing surface, creates a mechanical stress and a deflection of the spring element. One of a multitude of deflection detection methods may include the use of a laser light source focused on the microcantilever, with a photo-sensitive detector receiving reflected laser impulses. The microcantilevered spring element is approximately 1 to 100 .mu.m long, approximately 1 to 50 .mu.m wide, and approximately 0.3 to 3.0 .mu.m thick. An accuracy of detection of deflections of the cantilever is provided in the range of 0.01 nanometers of deflection. The microcantilever apparatus and a method of detection of parameters require only microliters of a sample to be placed on, or near the spring element surface. The method is extremely sensitive to the detection of the parameters to be measured.

Transposon Insertion Finder (TIF): a novel program for detection of de novo transpositions of transposable elements.

PubMed

Nakagome, Mariko; Solovieva, Elena; Takahashi, Akira; Yasue, Hiroshi; Hirochika, Hirohiko; Miyao, Akio

2014-03-14

Transposition event detection of transposable element (TE) in the genome using short reads from the next-generation sequence (NGS) was difficult, because the nucleotide sequence of TE itself is repetitive, making it difficult to identify locations of its insertions by alignment programs for NGS. We have developed a program with a new algorithm to detect the transpositions from NGS data. In the process of tool development, we used next-generation sequence (NGS) data of derivative lines (ttm2 and ttm5) of japonica rice cv. Nipponbare, regenerated through cell culture. The new program, called a transposon insertion finder (TIF), was applied to detect the de novo transpositions of Tos17 in the regenerated lines. TIF searched 300 million reads of a line within 20 min, identifying 4 and 12 de novo transposition in ttm2 and ttm5 lines, respectively. All of the transpositions were confirmed by PCR/electrophoresis and sequencing. Using the program, we also detected new transposon insertions of P-element from NGS data of Drosophila melanogaster. TIF operates to find the transposition of any elements provided that target site duplications (TSDs) are generated by their transpositions.

System and method for authentication of goods

DOEpatents

Kaish, Norman; Fraser, Jay; Durst, David I.

1999-01-01

An authentication system comprising a medium having a plurality of elements, the elements being distinctive, detectable and disposed in an irregular pattern or having an intrinsic irregularity. Each element is characterized by a determinable attribute distinct from a two-dimensional coordinate representation of simple optical absorption or simple optical reflection intensity. An attribute and position of the plurality of elements, with respect to a positional reference is detected. A processor generates an encrypted message including at least a portion of the attribute and position of the plurality of elements. The encrypted message is recorded in physical association with the medium. The elements are preferably dichroic fibers, and the attribute is preferably a polarization or dichroic axis, which may vary over the length of a fiber. An authentication of the medium based on the encrypted message may be authenticated with a statistical tolerance, based on a vector mapping of the elements of the medium, without requiring a complete image of the medium and elements to be recorded.

Piezoelectrically tunable resonance frequency beam utilizing a stress-sensitive film

DOEpatents

Thundat, Thomas G.; Wachter, Eric A.

2002-01-01

Methods and apparatus for detecting particular frequencies of acoustic vibration utilize a piezoelectrically-tunable beam element having a piezoelectric layer and a stress sensitive layer and means for providing an electrical potential across the piezoelectric layer to controllably change the beam's stiffness and thereby change its resonance frequency. It is then determined from the response of the piezoelectrically-tunable beam element to the acoustical vibration to which the beam element is exposed whether or not a particular frequency or frequencies of acoustic vibration are detected.

Automatic non-destructive system for quality assurance of welded elements in the aircraft industry

NASA Astrophysics Data System (ADS)

Chady, Tomasz; Waszczuk, Paweł; Szydłowski, Michał; Szwagiel, Mariusz

2018-04-01

Flaws that might be a result of the welding process have to be detected, in order to assure high quality thus reliability of elements exploited in aircraft industry. Currently the inspection stage is conducted manually by a qualified workforce. There are no commercially available systems that could support or replace humans in the flaw detection process. In this paper authors present a novel non-destructive system developed for quality assurance purposes of welded elements utilized in the aircraft industry.

Radiation sensitive devices and systems for detection of radioactive materials and related methods

DOEpatents

Kotter, Dale K

2014-12-02

Radiation sensitive devices include a substrate comprising a radiation sensitive material and a plurality of resonance elements coupled to the substrate. Each resonance element is configured to resonate responsive to non-ionizing incident radiation. Systems for detecting radiation from a special nuclear material include a radiation sensitive device and a sensor located remotely from the radiation sensitive device and configured to measure an output signal from the radiation sensitive device. In such systems, the radiation sensitive device includes a radiation sensitive material and a plurality of resonance elements positioned on the radiation sensitive material. Methods for detecting a presence of a special nuclear material include positioning a radiation sensitive device in a location where special nuclear materials are to be detected and remotely interrogating the radiation sensitive device with a sensor.

Automatic Constraint Detection for 2D Layout Regularization.

PubMed

Jiang, Haiyong; Nan, Liangliang; Yan, Dong-Ming; Dong, Weiming; Zhang, Xiaopeng; Wonka, Peter

2016-08-01

In this paper, we address the problem of constraint detection for layout regularization. The layout we consider is a set of two-dimensional elements where each element is represented by its bounding box. Layout regularization is important in digitizing plans or images, such as floor plans and facade images, and in the improvement of user-created contents, such as architectural drawings and slide layouts. To regularize a layout, we aim to improve the input by detecting and subsequently enforcing alignment, size, and distance constraints between layout elements. Similar to previous work, we formulate layout regularization as a quadratic programming problem. In addition, we propose a novel optimization algorithm that automatically detects constraints. We evaluate the proposed framework using a variety of input layouts from different applications. Our results demonstrate that our method has superior performance to the state of the art.

Body burden of toxic metals and rare earth elements in non-smokers, cigarette smokers and electronic cigarette users.

PubMed

Badea, Mihaela; Luzardo, Octavio P; González-Antuña, Ana; Zumbado, Manuel; Rogozea, Liliana; Floroian, Laura; Alexandrescu, Dana; Moga, Marius; Gaman, Laura; Radoi, Mariana; Boada, Luis D; Henríquez-Hernández, Luis Alberto

2018-06-13

Smoking is considered an important source for inorganic elements, most of them toxic for human health. During the last years, there has been a significant increase in the use of e-cigarettes, although the role of them as source of inorganic elements has not been well established. A cross-sectional study including a total of 150 subjects from Brasov (Romania), divided into three groups (non-smokers, cigarette smokers and electronic cigarettes smokers) were recruited to disclose the role of smoking on the human exposure to inorganic elements. Concentration of 42 elements, including trace elements, elements in the ATSDR's priority pollutant list and rare earth elements (REE) were measured by ICP-MS in the blood serum of participants. Cigarette smokers showed the highest levels of copper, molybdenum, zinc, antimony, and strontium. Electronic cigarette (e-cigarette) users presented the highest concentrations of selenium, silver, and vanadium. Beryllium, europium and lanthanides were detected more frequently among e-cigarette users (20.6%, 23.5%, and 14.7%) than in cigarette smokers (1.7%, 19.0%, and 12.1%, respectively); and the number of detected REE was also higher among e-cigarette users (11.8% of them showed more than 10 different elements). Serum levels of cerium and erbium increased as the duration of the use of e-cigarettes was longer. We have found that smoking is mainly a source of heavy metals while the use of e-cigarettes is a potential source of REE. However, these elements were detected at low concentrations. Copyright © 2018 Elsevier Inc. All rights reserved.

Discrimination of microbiological samples using femtosecond laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Baudelet, Matthieu; Yu, Jin; Bossu, Myriam; Jovelet, Julien; Wolf, Jean-Pierre; Amodeo, Tanguy; Fréjafon, Emeric; Laloi, Patrick

2006-10-01

Using femtosecond laser-induced breakdown spectroscopy, the authors have analyzed five different species of bacterium. Line emissions from six trace mineral elements, Na, Mg, P, K, Ca, and Fe, have been clearly detected. Their intensities correspond to relative concentrations of these elements contained in the analyzed samples. The authors demonstrate that the concentration profile of trace elements allows unambiguous discrimination of different bacteria. Quantitative differentiation has been made by representing bacteria in a six-dimension hyperspace with each of its axis representing a detected trace element. In such hyperspace, representative points of different species of bacterium are gathered in different and distinct volumes.

Concentrations of platinum group elements in 122 U.S. coal samples

USGS Publications Warehouse

Oman, C.L.; Finkelman, R.B.; Tewalt, S.J.

1997-01-01

Analysis of more than 13,000 coal samples by semi-quantitative optical emission spectroscopy (OES) indicates that concentrations of the platinum group elements (iridium, palladium, platinum, osmium, rhodium, and ruthenium) are less than 1 ppm in the ash, the limit of detection for this method of analysis. In order to accurately determine the concentration of the platinum group elements (PGE) in coal, additional data were obtained by inductively coupled plasma mass spectroscopy, an analytical method having part-per-billion (ppb) detection limits for these elements. These data indicate that the PGE in coal occur in concentrations on the order of 1 ppb or less.

Trace element analysis by EPMA in geosciences: detection limit, precision and accuracy

NASA Astrophysics Data System (ADS)

Batanova, V. G.; Sobolev, A. V.; Magnin, V.

2018-01-01

Use of the electron probe microanalyser (EPMA) for trace element analysis has increased over the last decade, mainly because of improved stability of spectrometers and the electron column when operated at high probe current; development of new large-area crystal monochromators and ultra-high count rate spectrometers; full integration of energy-dispersive / wavelength-dispersive X-ray spectrometry (EDS/WDS) signals; and the development of powerful software packages. For phases that are stable under a dense electron beam, the detection limit and precision can be decreased to the ppm level by using high acceleration voltage and beam current combined with long counting time. Data on 10 elements (Na, Al, P, Ca, Ti, Cr, Mn, Co, Ni, Zn) in olivine obtained on a JEOL JXA-8230 microprobe with tungsten filament show that the detection limit decreases proportionally to the square root of counting time and probe current. For all elements equal or heavier than phosphorus (Z = 15), the detection limit decreases with increasing accelerating voltage. The analytical precision for minor and trace elements analysed in olivine at 25 kV accelerating voltage and 900 nA beam current is 4 - 18 ppm (2 standard deviations of repeated measurements of the olivine reference sample) and is similar to the detection limit of corresponding elements. To analyse trace elements accurately requires careful estimation of background, and consideration of sample damage under the beam and secondary fluorescence from phase boundaries. The development and use of matrix reference samples with well-characterised trace elements of interest is important for monitoring and improving of the accuracy. An evaluation of the accuracy of trace element analyses in olivine has been made by comparing EPMA data for new reference samples with data obtained by different in-situ and bulk analytical methods in six different laboratories worldwide. For all elements, the measured concentrations in the olivine reference sample were found to be identical (within internal precision) to reference values, suggesting that achieved precision and accuracy are similar. The spatial resolution of EPMA in a silicate matrix, even at very extreme conditions (accelerating voltage 25 kV), does not exceed 7 - 8 μm and thus is still better than laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) or secondary ion mass spectrometry (SIMS) of similar precision. These make the electron microprobe an indispensable method with applications in experimental petrology, geochemistry and cosmochemistry.

[Distribution of chemical elements in whole blood and plasma].

PubMed

Barashkov, G K; Zaĭtseva, L I; Kondakhchan, M A; Konstantinova, E A

2003-01-01

The distribution factor (Fd) of 35 elements of plasma and whole blood in 26 healthy men and women was detected by ICP-OES. Usilig this parameter the elements were subdivided in 3 pools. 9 of them have Fd higher than 1.5 ("elements of plasma"-Ag, Ca, Cu, In, Li, Na, Se, Si, Sr); 6 have lower than 0.5 ("elements of blood cells"-Fe, K, Mn, Ni, V, Zn), other 20-about 1 ("blood elements"). Fd of all elements depends on ionic radius. Elements of 2nd sub-groups of all groups of Mendeleev's periodic table ("heavy metals") depend on the similar law: "with growing of ionic radius the concentration of elements in plasma enhances". In alkaline metals Fd depends on the opposite law:" with growing of ionic radius of alkaline metal the quantity of elements in blood cells enhance". Dependence of Fd on the value of atomic mass in periods or in exterior electronic cloud (s-, p-, d-, f-) was not established. The table of distribution of all detected elements in whole blood in relation to 8 macroelements (Ca, Mg, K, Na, S, P, Fe, Zn,) is presented, as a basic diagnostic criteria in metal-ligand homeostasis disturbance.

Research on improved edge extraction algorithm of rectangular piece

NASA Astrophysics Data System (ADS)

He, Yi-Bin; Zeng, Ya-Jun; Chen, Han-Xin; Xiao, San-Xia; Wang, Yan-Wei; Huang, Si-Yu

Traditional edge detection operators such as Prewitt operator, LOG operator and Canny operator, etc. cannot meet the requirements of the modern industrial measurement. This paper proposes a kind of image edge detection algorithm based on improved morphological gradient. It can be detect the image using structural elements, which deals with the characteristic information of the image directly. Choosing different shapes and sizes of structural elements to use together, the ideal image edge information can be detected. The experimental result shows that the algorithm can well extract image edge with noise, which is clearer, and has more detailed edges compared with the previous edge detection algorithm.

ICP-MS as a novel detection system for quantitative element-tagged immunoassay of hidden peanut allergens in foods.

PubMed

Careri, Maria; Elviri, Lisa; Mangia, Alessandro; Mucchino, Claudio

2007-03-01

A novel ICP-MS-based ELISA immunoassay via element-tagged determination was devised for quantitative analysis of hidden allergens in food. The method was able to detect low amounts of peanuts (down to approximately 2 mg peanuts kg(-1) cereal-based matrix) by using a europium-tagged antibody. Selectivity was proved by the lack of detectable cross-reaction with a number of protein-rich raw materials.

Image processing occupancy sensor

DOEpatents

Brackney, Larry J.

2016-09-27

A system and method of detecting occupants in a building automation system environment using image based occupancy detection and position determinations. In one example, the system includes an image processing occupancy sensor that detects the number and position of occupants within a space that has controllable building elements such as lighting and ventilation diffusers. Based on the position and location of the occupants, the system can finely control the elements to optimize conditions for the occupants, optimize energy usage, among other advantages.

Optimizing detector geometry for trace element mapping by X-ray fluorescence

DOE PAGES

Sun, Yue; Gleber, Sophie -Charlotte; Jacobsen, Chris; ...

2015-01-01

We report that trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral responsemore » of energy dispersive detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. In conclusion, we conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples.« less

Optimizing detector geometry for trace element mapping by X-ray fluorescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Yue; Gleber, Sophie -Charlotte; Jacobsen, Chris

We report that trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral responsemore » of energy dispersive detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. In conclusion, we conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples.« less

Ice Detection and Mitigation Device

NASA Technical Reports Server (NTRS)

Gambino, Richard J. (Inventor); Gouldstone, Christopher (Inventor); Gutleber, Jonathan (Inventor); Hubble, David (Inventor); Trelewicz, Jason (Inventor)

2016-01-01

A method for deicing an aerostructure includes driving a sensing current through a heater element coated to an aerostructure, the heater element having a resistance that is temperature dependent. A resistance of the heater element is monitored. It is determined whether there is icing at the heater element using the monitored resistance of the heater element. A melting current is driven through the heater element when it is determined that there is icing at the heater element.

Comparing the detection of iron-based pottery pigment on a carbon-coated sherd by SEM-EDS and by Micro-XRF-SEM.

PubMed

Pendleton, Michael W; Washburn, Dorothy K; Ellis, E Ann; Pendleton, Bonnie B

2014-03-01

The same sherd was analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) and a micro X-ray fluorescence tube attached to a scanning electron microscope (Micro-XRF-SEM) to compare the effectiveness of elemental detection of iron-based pigment. To enhance SEM-EDS mapping, the sherd was carbon coated. The carbon coating was not required to produce Micro-XRF-SEM maps but was applied to maintain an unbiased comparison between the systems. The Micro-XRF-SEM analysis was capable of lower limits of detection than that of the SEM-EDS system, and therefore the Micro-XRF-SEM system could produce elemental maps of elements not easily detected by SEM-EDS mapping systems. Because SEM-EDS and Micro-XRF-SEM have been used for imaging and chemical analysis of biological samples, this comparison of the detection systems should be useful to biologists, especially those involved in bone or tooth (hard tissue) analysis.

Comparing the Detection of Iron-Based Pottery Pigment on a Carbon-Coated Sherd by SEM-EDS and by Micro-XRF-SEM

PubMed Central

Pendleton, Michael W.; Washburn, Dorothy K.; Ellis, E. Ann; Pendleton, Bonnie B.

2014-01-01

The same sherd was analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) and a micro X-ray fluorescence tube attached to a scanning electron microscope (Micro-XRF-SEM) to compare the effectiveness of elemental detection of iron-based pigment. To enhance SEM-EDS mapping, the sherd was carbon coated. The carbon coating was not required to produce Micro-XRF-SEM maps but was applied to maintain an unbiased comparison between the systems. The Micro-XRF-SEM analysis was capable of lower limits of detection than that of the SEM-EDS system, and therefore the Micro-XRF-SEM system could produce elemental maps of elements not easily detected by SEM-EDS mapping systems. Because SEM-EDS and Micro-XRF-SEM have been used for imaging and chemical analysis of biological samples, this comparison of the detection systems should be useful to biologists, especially those involved in bone or tooth (hard tissue) analysis. PMID:24600333

Study on on-machine defects measuring system on high power laser optical elements

NASA Astrophysics Data System (ADS)

Luo, Chi; Shi, Feng; Lin, Zhifan; Zhang, Tong; Wang, Guilin

2017-10-01

The influence of surface defects on high power laser optical elements will cause some harm to the performances of imaging system, including the energy consumption and the damage of film layer. To further increase surface defects on high power laser optical element, on-machine defects measuring system was investigated. Firstly, the selection and design are completed by the working condition analysis of the on-machine defects detection system. By designing on processing algorithms to realize the classification recognition and evaluation of surface defects. The calibration experiment of the scratch was done by using the self-made standard alignment plate. Finally, the detection and evaluation of surface defects of large diameter semi-cylindrical silicon mirror are realized. The calibration results show that the size deviation is less than 4% that meet the precision requirement of the detection of the defects. Through the detection of images the on-machine defects detection system can realize the accurate identification of surface defects.

Deep Optical Spectroscopy of Planetary Nebulae: The Search for Neutron-Capture Elements

NASA Astrophysics Data System (ADS)

Sterling, Nicholas C.; Garofali, K.; Dinerstein, H. L.; Hwang, S.; Redfield, S.

2013-01-01

We present deep, high-resolution (R=36,700) optical spectra of five planetary nebulae (PNe), taken with the 2D-coude echelle spectrograph on the 2.7-m Harlan J. Smith Telescope at McDonald Observatory. These observations are part of a larger optical survey of PNe, designed to unambiguously detect emission lines from neutron(n)-capture elements (atomic number Z>30). The abundances of these elements are of particular interest in PNe, since they can be produced by slow n-capture nucleosynthesis (the ``s-process'') during the asymptotic giant branch (AGB) stage of evolution of PN progenitor stars. The first large-scale investigation of n-capture element abundances in PNe (Sterling & Dinerstein 2008, ApJS, 174, 157) surveyed [Kr III] and [Se IV] transitions in the K band spectra of more than 80 PNe. However, the abundances derived from these data relied on ionization corrections that were often large and uncertain due to the detection of only one ion per element. Transitions of other Se and Kr ions, as well as many other trans-iron species, reside at optical wavelengths. High-resolution spectra are essential to unequivocally identify these lines and resolve potential blends with other species. The spectra we present are rich in emission features, with between 125 and 600 distinct lines detected in each PN. Emission from at least one Kr ion is detected in all five objects, and two (Hb 12 and J 900) exhibit emission from multiple Kr ions. We detected multiple Xe ions in J 900, as well as Se, Br, and Rb lines. Hb 12 also exhibits Xe emission, and the first detection of [Se II] in a PN to our knowledge. The spectra display a wealth of other emission lines, including permitted features of second-row elements and forbidden transitions of several iron-peak elements (e.g., Cr, Mn, Fe, Co, Ni, and Cu). Our survey makes it possible to derive more accurate Se and Kr abundances in PNe, and reveals the enrichment of other trans-iron elements. This enables more accurate s-process enrichment factors to be derived for PNe, providing important constraints to models of AGB nucleosynthesis and the chemical evolution of trans-iron nuclides. This research was supported by NSF awards AST-0708425 and AST-901432.

Organochlorine compounds and trace elements in fish tissue and ancillary data for the Connecticut, Housatonic, and Thames river basins study unit, 1992-94

USGS Publications Warehouse

Coles, J.F.

1996-01-01

Concentrations of organochlorine compounds and trace elements were assayed in fish tissue collected from the Connecticut, Housatonic, and Thames River Basins Study Unit, 1992-94. These data were collected to determine the occurrence and distribution of organochlorine compounds and trace elements in the study unit. Ancillary data included are land-use categories by percentage of the sampling-site basins and the size, gender, and age of the individual fish collected for this study. Concentrations of 28 organochlorine compounds in composited whole fish samples were measured at 32 sites, and concentrations of 22 trace elements in composited fish liver samples were measured at 14 of the 32 sites. Most frequently detected organochlorines were DDT related compounds at 31 sites, total PCBs at 28 sites, and chlordane related compounds at 25 sites. Concentrations of total PCBs in fish tissue were generally higher at the large river sites than at the smaller tributary sites. Concentrations of chlordane-related compounds in fish tissue were higher at sites from more urbanized basins than at sites from predominately agriculture and forested basins. Concentrations of the DDT related compounds were undifferentiated among sites comprising different land uses. Trace elements detected at all 14 sites included boron, copper, iron, manganese, molybdenum, selenium, and zinc. Trace elements detected at 10 or more sites included arsenic, mercury, silver, strontium, and vanadium. Antimony, beryllium, and uranium were not detected at any site.

REACTOR FUEL ELEMENTS TESTING CONTAINER

DOEpatents

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)

Nuclear Structure in China 2010

NASA Astrophysics Data System (ADS)

Bai, Hong-Bo; Meng, Jie; Zhao, En-Guang; Zhou, Shan-Gui

2011-08-01

Personal view on nuclear physics research / Jie Meng -- High-spin level structures in [symbol]Zr / X. P. Cao ... [et al.] -- Constraining the symmetry energy from the neutron skin thickness of tin isotopes / Lie-Wen Chen ... [et al.] -- Wobbling rotation in atomic nuclei / Y. S. Chen and Zao-Chun Gao -- The mixing of scalar mesons and the possible nonstrange dibaryons / L. R. Dai ... [et al.] -- Net baryon productions and gluon saturation in the SPS, RHIC and LHC energy regions / Sheng-Qin Feng -- Production of heavy isotopes with collisions between two actinide nuclides / Z. Q. Feng ... [et al.] -- The projected configuration interaction method / Zao-Chun Gao and Yong-Shou Chen -- Applications of Nilsson mean-field plus extended pairing model to rare-earth nuclei / Xin Guan ... [et al.] -- Complex scaling method and the resonant states / Jian-You Guo ... [et al.] -- Probing the equation of state by deep sub-barrier fusion reactions / Hong-Jun Hao and Jun-Long Tian -- Doublet structure study in A[symbol]105 mass region / C. Y. He ... [et al.] -- Rotational bands in transfermium nuclei / X. T. He -- Shape coexistence and shape evolution [symbol]Yb / H. Hua ... [et al.] -- Multistep shell model method in the complex energy plane / R. J. Liotta -- The evolution of protoneutron stars with kaon condensate / Ang Li -- High spin structures in the [symbol]Lu nucleus / Li Cong-Bo ... [et al.] -- Nuclear stopping and equation of state / QingFeng Li and Ying Yuan -- Covariant description of the low-lying states in neutron-deficient Kr isotopes / Z. X. Li ... [et al.] -- Isospin corrections for superallowed [symbol] transitions / HaoZhao Liang ... [et al.] -- The positive-parity band structures in [symbol]Ag / C. Liu ... [et al.] -- New band structures in odd-odd [symbol]I and [symbol]I / Liu GongYe ... [et al.] -- The sd-pair shell model and interacting boson model / Yan-An Luo ... [et al.] -- Cross-section distributions of fragments in the calcium isotopes projectile fragmentation at the intermediate energy / C. W. Ma ... [et al.].Systematic study of spin assignment and dynamic moment of inertia of high-j intruder band in [symbol]In / K. Y. Ma ... [et al.] -- Signals of diproton emission from the three-body breakup channel of [symbol]Al and [symbol]Mg / Ma Yu-Gang ... [et al.] -- Uncertainties of Th/Eu and Th/Hf chronometers from nucleus masses / Z. M. Niu ... [et al.] -- The chiral doublet bands with [symbol] configuration in A[symbol]100 mass region / B. Qi ... [et al.] -- [symbol] formation probabilities in nuclei and pairing collectivity / Chong Qi -- A theoretical prospective on triggered gamma emission from [symbol]Hf[symbol] isomer / ShuiFa Shen ... [et al.] -- Study of nuclear giant resonances using a Fermi-liquid method / Bao-Xi Sun -- Rotational bands in doubly odd [symbol]Sb / D. P. Sun ... [et al.] -- The study of the neutron N=90 nuclei / W. X. Teng ... [et al.] -- Dynamical modes and mechanisms in ternary reaction of [symbol]Au+[symbol]Au / Jun-Long Tian ... [et al.] -- Dynamical study of X(3872) as a D[symbol] molecular state / B. Wang ... [et al.] -- Super-heavy stability island with a semi-empirical nuclear mass formula / N. Wang ... [et al.] -- Pseudospin partner bands in [symbol]Sb / S. Y. Wang ... [et al.] -- Study of elastic resonance scattering at CIAE / Y. B. Wang ... [et al.] -- Systematic study of survival probability of excited superheavy nuclei / C. J. Xia ... [et al.] -- Angular momentum projection of the Nilsson mean-field plus nearest-orbit pairing interaction model / Ming-Xia Xie ... [et al.] -- Possible shape coexistence for [symbol]Sm in a reflection-asymmetric relativistic mean-field approach / W. Zhang ... [et al.] -- Nuclear pairing reduction due to rotation and blocking / Zhen-Hua Zhang -- Nucleon pair approximation of the shell model: a review and perspective / Y. M. Zhao ... [et al.] -- Band structures in doubly odd [symbol]I / Y. Zheng ... [et al.] -- Lifetimes of high spin states in [symbol]Ag / Y. Zheng ... [et al.] -- Effect of tensor interaction on the shell structure of superheavy nuclei / Xian-Rong Zhou ... [et al.].

Integrated Performance Testing Workshop, Modules 6 - 11

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leach, Janice; Torres, Teresa M.

These modules cover performance testing of: Interior Detection Systems; Access Controls; Exterior Detection Systems; Video Assessment Systems; SNM / Contraband Detection Systems; Access Delay Elements

ICP-MS: Analytical Method for Identification and Detection of Elemental Impurities.

PubMed

Mittal, Mohini; Kumar, Kapil; Anghore, Durgadas; Rawal, Ravindra K

2017-01-01

Aim of this article is to review and discuss the currently used quantitative analytical method ICP-MS, which is used for quality control of pharmaceutical products. ICP-MS technique has several applications such as determination of single elements, multi element analysis in synthetic drugs, heavy metals in environmental water, trace element content of selected fertilizers and dairy manures. ICP-MS is also used for determination of toxic and essential elements in different varieties of food samples and metal pollutant present in the environment. The pharmaceuticals may generate impurities at various stages of development, transportation and storage which make them risky to be administered. Thus, it is essential that these impurities must be detected and quantified. ICP-MS plays an important function in the recognition and revealing of elemental impurities. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

New Global Calculation of Nuclear Masses and Fission Barriers for Astrophysical Applications

NASA Astrophysics Data System (ADS)

Möller, P.; Sierk, A. J.; Bengtsson, R.; Ichikawa, T.; Iwamoto, A.

2008-05-01

The FRDM(1992) mass model [1] has an accuracy of 0.669 MeV in the region where its parameters were determined. For the 529 masses that have been measured since, its accuracy is 0.46 MeV, which is encouraging for applications far from stability in astrophysics. We are developing an improved mass model, the FRDM(2008). The improvements in the calculations with respect to the FRDM(1992) are in two main areas. (1) The macroscopic model parameters are better optimized. By simulation (adjusting to a limited set of now known nuclei) we can show that this actually makes the results more reliable in new regions of nuclei. (2) The ground-state deformation parameters are more accurately calculated. We minimize the energy in a four-dimensional deformation space (ɛ2, V3, V4, V6,) using a grid interval of 0.01 in all 4 deformation variables. The (non-finalized) FRDM (2008-a) has an accuracy of 0.596 MeV with respect to the 2003 Audi mass evaluation before triaxial shape degrees of freedom are included (in progress). When triaxiality effects are incorporated preliminary results indicate that the model accuracy will improve further, to about 0.586 MeV. We also discuss very large-scale fission-barrier calculations in the related FRLDM (2002) model, which has been shown to reproduce very satisfactorily known fission properties, for example barrier heights from 70Se to the heaviest elements, multiple fission modes in the Ra region, asymmetry of mass division in fission and the triple-humped structure found in light actinides. In the superheavy region we find barriers consistent with the observed half-lives. We have completed production calculations and obtain barrier heights for 5254 nuclei heavier than A = 170 for all nuclei between the proton and neutron drip lines. The energy is calculated for 5009325 different shapes for each nucleus and the optimum barrier between ground state and separated fragments is determined by use of an ``immersion'' technique.

Radioisotope Production for Medical and Physics Applications

NASA Astrophysics Data System (ADS)

Mausner, Leonard

2012-10-01

Radioisotopes are critical to the science and technology base of the US. Discoveries and applications made as a result of the availability of radioisotopes span widely from medicine, biology, physics, chemistry and homeland security. The clinical use of radioisotopes for medical diagnosis is the largest sector of use, with about 16 million procedures a year in the US. The use of ^99Mo/^99mTc generator and ^18F make up the majority, but ^201Tl, ^123I, ^111In, and ^67Ga are also used routinely to perform imaging of organ function. Application of radioisotopes for therapy is dominated by use of ^131I for thyroid malignancies, ^90Y for some solid tumors, and ^89Sr for bone cancer, but production of several more exotic species such as ^225Ac and ^211At are of significant current research interest. In physics ^225Ra is of interest for CP violation studies, and the actinides ^242Am, ^249Bk, and ^254Es are needed as targets for experiments to create superheavy elements. Large amounts of ^252Cf are needed as a fission source for the CARIBU experiment at ANL. The process of radioisotope production is multidisciplinary. Nuclear physics input based on nuclear reaction excitation function data is needed to choose an optimum target/projectile in order to maximize desired isotope production and minimize unwanted byproducts. Mechanical engineering is needed to address issues of target heating, induced mechanical stress and material compatibility of target and claddings. Radiochemists are involved as well since chemical separation to purify the desired final radioisotope product from the bulk target and impurities is also usually necessary. Most neutron rich species are produced at a few government and university reactors. Other radioisotopes are produced in cyclotrons in the commercial sector, university/hospital based facilities, and larger devices at the DOE labs. The landscape of US facilities, the techniques involved, and current supply challenges will be reviewed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guliyev, I.A.; Aliyev, A.A.; Rahmanov, R.R.

Azerbaijan is a classic region for the study of mud volcanism. Of the 700 mud volcanoes known in the world, 220 are in Azerbaijan. These are of great interest, not least in relation to oil and gas exploration since they give information on subsurface sediments beyond the reach of drilling. Mud volcanoes are clearly visible on satellite images. They are confined to structural lineaments and associated fractures. Changes in the morphology of some mud volcanoes post-eruption can be detected from a series of images pre-dating and post-dating eruptions. Mud volcanoes are notable for gradients of temperature that are by anmore » order of magnitude or a factor of 102 greater than the temperature gradients established elsewhere. The gases of mud volcanoes consist mainly of methane (95-100%). There are small amounts of C{sub 2-6}, CO{sub 2}, N{sub 2}, He and Ar. The isotopic composition of carbon (ICC) within the methane varies from -61.29. to -35.W{close_quotes} which is isotopically heavier than the methane from producing fields. The ICC of the CO{sub 2} has a very wide range (from -49.6% to +23.1%), indicating several sources of its formation. The isotopically superheavy CO{sub 2} (+5%) is especially interesting. Oils from mud volcanoes are typically severely biodegraded. Their ICC ranges from -24.76% to -28.2%. A relationship between {partial_derivative}{sup l3}C of oils and ages of accumulations has been established. Waters of mud volcanoes are lightly mineralised, containing chiefly bicarbonates and sodium. The hydrogen composition of the water is abnormally heavy. Ejected rocks from mud volcanoes range in age from Cretaceous - Pliocene. Their study suggests that deeply buried reservoirs maintain good poroperm characteristics because of relatively little catagenesis.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Yue; Gleber, Sophie-Charlotte; Jacobsen, Chris

Trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral response of energy dispersivemore » detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. We conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples.« less

Water-quality assessment of the Rio Grande Valley, Colorado, New Mexico and Texas; organic compounds and trace elements in bed sediment and fish tissue, 1992-93

USGS Publications Warehouse

Carter, L.F.; Anderholm, S.K.

1997-01-01

The occurrence and distribution of contaminants in aquatic systems are major components of the National Water-Quality Assessment (NAWQA) Program. Bed-sediment samples were collected at 18 sites in the Rio Grande Valley study unit between September 1992 and March 1993 to characterize the geographic distribution of organic compounds, including chlorinated insecticides, polychlorinated biphenyls (PCB's), and other chlorinated hydrocarbons, and also trace elements. Two-millimeter-size- fraction sediment was analyzed for organic compounds and less than 63-micron-size-fraction sediment was analyzed for trace elements. Concentrations of p,p'-DDE were detected in 33 percent of the bed-sediment samples. With the exception of DDT-related compounds, no other organochlorine insecticides or polychlorinated biphenyls were detected in samples of bed sediment. Whole-body fish samples were collected at 11 of the bed- sediment sites and analyzed for organic compounds. Organic compounds were reported more frequently in samples of fish, and more types of organic compounds were found in whole-body fish samples than in bed-sediment samples. Concentrations of p,p'-DDE were detected in 91 percent of whole-body fish samples. Polychlorinated biphenyls, cis-chlordane, trans-chlordane, trans- nonachlor, and hexachlorobenzene were other organic compounds detected in whole-body samples of fish from at least one site. Because of the extent of mineralized areas in the Rio Grande Basin arsenic, cadmium, copper, lead, mercury, selenium, and zinc concentrations in bed-sediment samples could represent natural conditions at most sites. However, a combination of natural conditions and human activities appears to be associated with elevated trace-element concentrations in the bed-sediment sample from the site Rio Grande near Creede, Colorado, because this sample exceeded the background trace-element concentrations calculated for this study. Fish-liver samples were collected at 12 of the bed-sediment sites and analyzed for trace elements. Certain trace elements were detected at higher concentrations in fish-liver samples than in bed-sediment samples from the same site. Both bed-sediment and fish-tissue samples are necessary for a complete environmental assessment of the occurrence and distribution of trace elements.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gundlach-Graham, Alexander W.; Dennis, Elise; Ray, Steven J.

An inductively coupled plasma distance-of-flight mass spectrometer (ICP-DOFMS) has been coupled with laser-ablation (LA) sample introduction for the elemental analysis of solids. ICP-DOFMS is well suited for the analysis of laser-generated aerosols because it offers both high-speed mass analysis and simultaneous multi-elemental detection. Here, we evaluate the analytical performance of the LA-ICP-DOFMS instrument, equipped with a microchannel plate-based imaging detector, for the measurement of steady-state LA signals, as well as transient signals produced from single LA events. Steady-state detection limits are 1 mg g1, and absolute single-pulse LA detection limits are 200 fg for uranium; the system is shown capablemore » of performing time-resolved single-pulse LA analysis. By leveraging the benefits of simultaneous multi-elemental detection, we also attain a good shot-to-shot reproducibility of 6% relative standard deviation (RSD) and isotope-ratio precision of 0.3% RSD with a 10 s integration time.« less

Trace element abundance determinations by Synchrotron X Ray Fluorescence (SXRF) on returned comet nucleus mineral grains

NASA Technical Reports Server (NTRS)

Flynn, G. J.; Sutton, S. R.

1989-01-01

Trace element analyses were performed on bulk cosmic dust particles by Proton Induced X Ray Emission (PIXE) and Synchrotron X Ray Fluorescence (SXRF). When present at or near chondritic abundances the trace elements K, Ti, Cr, Mn, Cu, Zn, Ga, Ge, Se, and Br are presently detectable by SXRF in particles of 20 micron diameter. Improvements to the SXRF analysis facility at the National Synchrotron Light Source presently underway should increase the range of detectable elements and permit the analysis of smaller samples. In addition the Advanced Photon Source will be commissioned at Argonne National Laboratory in 1995. This 7 to 8 GeV positron storage ring, specifically designed for high-energy undulator and wiggler insertion devices, will be an ideal source for an x ray microprobe with one micron spatial resolution and better than 100 ppb elemental sensitivity for most elements. Thus trace element analysis of individual micron-sized grains should be possible by the time of the comet nucleus sample return mission.

Molecular manipulations for enhancing luminescent bioreporters performance in the detection of toxic chemicals.

PubMed

Yagur-Kroll, Sharon; Belkin, Shimshon

2014-01-01

Microbial whole-cell bioreporters are genetically modified microorganisms that produce a quantifiable output in response to the presence of toxic chemicals or other stress factors. These bioreporters harbor a genetic fusion between a sensing element (usually a gene regulatory element responsive to the target) and a reporter element, the product of which may be quantitatively monitored either by its presence or by its activity. In this chapter we review genetic manipulations undertaken in order to improve bioluminescent bioreporter performance by increasing luminescent output, lowering the limit of detection, and shortening the response time. We describe molecular manipulations applied to all aspects of whole-cell bioreporters: the host strain, the expression system, the sensing element, and the reporter element. The molecular construction of whole-cell luminescent bioreporters, harboring fusions of gene promoter elements to reporter genes, has been around for over three decades; in most cases, these two genetic elements are combined "as is." This chapter outlines diverse molecular manipulations for enhancing the performance of such sensors.

Method for measuring dose-equivalent in a neutron flux with an unknown energy spectra and means for carrying out that method

DOEpatents

Distenfeld, Carl H.

1978-01-01

A method for measuring the dose-equivalent for exposure to an unknown and/or time varing neutron flux which comprises simultaneously exposing a plurality of neutron detecting elements of different types to a neutron flux and combining the measured responses of the various detecting elements by means of a function, whose value is an approximate measure of the dose-equivalent, which is substantially independent of the energy spectra of the flux. Also, a personnel neutron dosimeter, which is useful in carrying out the above method, comprising a plurality of various neutron detecting elements in a single housing suitable for personnel to wear while working in a radiation area.

Measurement of Irradiated Pyroprocessing Samples via Laser Induced Breakdown Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phongikaroon, Supathorn

The primary objective of this research is to develop an applied technology and provide an assessment to remotely measure and analyze the real time or near real time concentrations of used nuclear fuel (UNF) dissolute in electrorefiners. Here, Laser-Induced Breakdown Spectroscopy (LIBS), in UNF pyroprocessing facilities will be investigated. LIBS is an elemental analysis method, which is based on the emission from plasma generated by focusing a laser beam into the medium. This technology has been reported to be applicable in the media of solids, liquids (includes molten metals), and gases for detecting elements of special nuclear materials. The advantagesmore » of applying the technology for pyroprocessing facilities are: (i) Rapid real-time elemental analysis|one measurement/laser pulse, or average spectra from multiple laser pulses for greater accuracy in < 2 minutes; (ii) Direct detection of elements and impurities in the system with low detection limits|element specific, ranging from 2-1000 ppm for most elements; and (iii) Near non-destructive elemental analysis method (about 1 g material). One important challenge to overcome is achieving high-resolution spectral analysis to quantitatively analyze all important fission products and actinides. Another important challenge is related to accessibility of molten salt, which is heated in a heavily insulated, remotely operated furnace in a high radiation environment with an argon atmosphere.« less

Method and apparatus for diagnosing breached fuel elements

DOEpatents

Gross, K.C.; Lambert, J.D.B.; Nomura, S.

1987-03-02

The invention provides an apparatus and method for diagnosing breached fuel elements in a nuclear reactor. A detection system measures the activity of isotopes from the cover gas in the reactor. A data acquisition and processing system monitors the detection system and corrects for the effects of the cover-gas clean up system on the measured activity and further calculates the derivative curve of the corrected activity as a function of time. A plotting system graphs the derivative curve, which represents the instantaneous release rate of fission gas from a breached fuel element. 8 figs.

Sub-micron surface plasmon resonance sensor systems

NASA Technical Reports Server (NTRS)

Glazier, James A. (Inventor); Amarie, Dragos (Inventor)

2012-01-01

A sensor for detecting the presence of a target analyte, ligand or molecule in a test fluid, comprising a light transmissive substrate on which an array of surface plasmon resonant (SPR) elements is mounted is described. A multi-channel sensor for detecting the presence of several targets with a single microchip sensor is described. A multi-channel sensor including collections of SPR elements which are commonly functionalized to one of several targets is also described. The detectors sense changes in the resonant response of the SPR elements indicative of binding with the targets.

Sub-micron surface plasmon resonance sensor systems

NASA Technical Reports Server (NTRS)

Amarie, Dragos (Inventor); Glazier, James A. (Inventor)

2011-01-01

A sensor for detecting the presence of a target analyte, ligand or molecule in a test fluid, comprising a light transmissive substrate on which an array of surface plasmon resonant (SPR) elements is mounted is described. A multichannel sensor for detecting the presence of several targets with a single microchip sensor is described. A multichannel sensor including collections of SPR elements which are commonly functionalized to one of several targets is also described. The detectors sense changes in the resonant response of the SPR elements indicative of binding with the targets.

Sub-micron surface plasmon resonance sensor systems

NASA Technical Reports Server (NTRS)

Glazier, James A. (Inventor); Dragnea, Bogdan (Inventor); Amarie, Dragos (Inventor)

2010-01-01

A sensor for detecting the presence of a target analyte, ligand or molecule in a test fluid, comprising a light transmissive substrate on which an array of surface plasmon resonant (SPR) elements is mounted is described. A multi-channel sensor for detecting the presence of several targets with a single microchip sensor is described. A multi-channel sensor including collections of SPR elements which are commonly functionalized to one of several targets is also described. The detectors sense changes in the resonant response of the SPR elements indicative of binding with the targets.

Sub-micron surface plasmon resonance sensor systems

NASA Technical Reports Server (NTRS)

Amarie, Dragos (Inventor); Glazier, James A. (Inventor); Dragnea, Bogdan (Inventor)

2010-01-01

A sensor for detecting the presence of a target analyte, ligand or molecule in a test fluid, comprising a light transmissive substrate on which an array of surface plasmon resonant (SPR) elements is mounted is described. A multi-channel sensor for detecting the presence of several targets with a single micro-chip sensor is described. A multi-channel sensor including collections of SPR elements which are commonly functionalized to one of several targets is also described. The detectors sense changes in the resonant response of the SPR elements indicative of binding with the targets.

Sub-micron surface plasmon resonance sensor systems

NASA Technical Reports Server (NTRS)

Glazier, James A. (Inventor); Amarie, Dragos (Inventor)

2011-01-01

A sensor for detecting the presence of a target analyte, ligand or molecule in a test fluid, comprising a light transmissive substrate on which an array of surface plasmon resonant (SPR) elements is mounted is described. A multi-channel sensor for detecting the presence of several targets with a single micro-chip sensor is described. A multi-channel sensor including collections of SPR elements which are commonly functionalized to one of several targets is also described. The detectors sense changes in the resonant response of the SPR elements indicative of binding with the targets.

1H-detected MAS solid-state NMR experiments enable the simultaneous mapping of rigid and dynamic domains of membrane proteins

NASA Astrophysics Data System (ADS)

Gopinath, T.; Nelson, Sarah E. D.; Veglia, Gianluigi

2017-12-01

Magic angle spinning (MAS) solid-state NMR (ssNMR) spectroscopy is emerging as a unique method for the atomic resolution structure determination of native membrane proteins in lipid bilayers. Although 13C-detected ssNMR experiments continue to play a major role, recent technological developments have made it possible to carry out 1H-detected experiments, boosting both sensitivity and resolution. Here, we describe a new set of 1H-detected hybrid pulse sequences that combine through-bond and through-space correlation elements into single experiments, enabling the simultaneous detection of rigid and dynamic domains of membrane proteins. As proof-of-principle, we applied these new pulse sequences to the membrane protein phospholamban (PLN) reconstituted in lipid bilayers under moderate MAS conditions. The cross-polarization (CP) based elements enabled the detection of the relatively immobile residues of PLN in the transmembrane domain using through-space correlations; whereas the most dynamic region, which is in equilibrium between folded and unfolded states, was mapped by through-bond INEPT-based elements. These new 1H-detected experiments will enable one to detect not only the most populated (ground) states of biomacromolecules, but also sparsely populated high-energy (excited) states for a complete characterization of protein free energy landscapes.

Methods for identification and verification using vacuum XRF system

NASA Technical Reports Server (NTRS)

Kaiser, Bruce (Inventor); Schramm, Fred (Inventor)

2005-01-01

Apparatus and methods in which one or more elemental taggants that are intrinsically located in an object are detected by x-ray fluorescence analysis under vacuum conditions to identify or verify the object's elemental content for elements with lower atomic numbers. By using x-ray fluorescence analysis, the apparatus and methods of the invention are simple and easy to use, as well as provide detection by a non line-of-sight method to establish the origin of objects, as well as their point of manufacture, authenticity, verification, security, and the presence of impurities. The invention is extremely advantageous because it provides the capability to measure lower atomic number elements in the field with a portable instrument.

Development of Multiple-Element Flame Emission Spectrometer Using CCD Detection

ERIC Educational Resources Information Center

Seney, Caryn S.; Sinclair, Karen V.; Bright, Robin M.; Momoh, Paul O.; Bozeman, Amelia D.

2005-01-01

The full wavelength coverage of charge coupled device (CCD) detector when coupled with an echelle spectrography, the system allows for simultaneously multiple element spectroscopy to be performed. The multiple-element flame spectrometer was built and characterized through the analysis of environmentally significant elements such as Ca, K, Na, Cu,…

Elemental ratios for characterization of quantum-dots populations in complex mixtures by asymmetrical flow field-flow fractionation on-line coupled to fluorescence and inductively coupled plasma mass spectrometry.

PubMed

Menendez-Miranda, Mario; Fernandez-Arguelles, Maria T; Costa-Fernandez, Jose M; Encinar, Jorge Ruiz; Sanz-Medel, Alfredo

2014-08-11

Separation and identification of nanoparticles of different composition, with similar particle diameter, coexisting in heterogeneous suspensions of polymer-coated CdSe/ZnS quantum dots (QDs) have been thoroughly assessed by asymmetric flow field-flow fractionation (AF4) coupled on-line to fluorescence and inductively coupled plasma mass spectrometry (ICPMS) detectors. Chemical characterization of any previously on-line separated nanosized species was achieved by the measurement of the elemental molar ratios of every element involved in the synthesis of the QDs, using inorganic standards and external calibration by flow injection analysis (FIA). Such elemental molar ratios, strongly limited so far to pure single nanoparticles suspensions, have been achieved with adequate accuracy by coupling for the first time an ICP-QQQ instrument to an AF4 system. This hyphenation turned out to be instrumental to assess the chemical composition of the different populations of nanoparticles coexisting in the relatively complex mixtures, due to its capabilities to detect the hardly detectable elements involved in the synthesis. Interestingly such information, complementary to that obtained by fluorescence, was very valuable to detect and identify unexpected nanosized species, present at significant level, produced during QDs synthesis and hardly detectable by standard approaches. Copyright © 2014. Published by Elsevier B.V.

A novel vacuum spectrometer for total reflection x-ray fluorescence analysis with two exchangeable low power x-ray sources for the analysis of low, medium, and high Z elements in sequence

NASA Astrophysics Data System (ADS)

Wobrauschek, P.; Prost, J.; Ingerle, D.; Kregsamer, P.; Misra, N. L.; Streli, C.

2015-08-01

The extension of the detectable elemental range with Total Reflection X-ray Fluorescence (TXRF) analysis is a challenging task. In this paper, it is demonstrated how a TXRF spectrometer is modified to analyze elements from carbon to uranium. Based on the existing design of a vacuum TXRF spectrometer with a 12 specimen sample changer, the following components were renewed: the silicon drift detector with 20 mm2 active area and having a special ultra-thin polymer window allowing the detection of elements from carbon upwards. Two exchangeable X-ray sources guarantee the efficient excitation of both low and high Z elements. These X-ray sources were two light-weighted easily mountable 35 W air-cooled low-power tubes with Cr and Rh anodes, respectively. The air cooled tubes and the Peltier-cooled detector allowed to construct a transportable tabletop spectrometer with compact dimensions, as neither liquid nitrogen cooling for the detector nor a water cooling circuit and a bulky high voltage generator for the X-ray tubes are required. Due to the excellent background conditions as a result of the TXRF geometry, detection limits of 150 ng for C, 12 ng for F, and 3.3 ng for Na have been obtained using Cr excitation in vacuum. For Rh excitation, the detection limits of 90 pg could be achieved for Sr. Taking 10 to 20 μl of sample volume, extrapolated detection limits in the ng/g (ppb) range are resulting in terms of concentration.

Monitoring arrangement for vented nuclear fuel elements

DOEpatents

Campana, Robert J.

1981-01-01

In a nuclear fuel reactor core, fuel elements are arranged in a closely packed hexagonal configuration, each fuel element having diametrically opposed vents permitting 180.degree. rotation of the fuel elements to counteract bowing. A grid plate engages the fuel elements and forms passages for communicating sets of three, four or six individual vents with respective monitor lines in order to communicate vented radioactive gases from the fuel elements to suitable monitor means in a manner readily permitting detection of leakage in individual fuel elements.

Terahertz imaging devices and systems, and related methods, for detection of materials

DOEpatents

Kotter, Dale K.

2016-11-15

Terahertz imaging devices may comprise a focal plane array including a substrate and a plurality of resonance elements. The plurality of resonance elements may comprise a conductive material coupled to the substrate. Each resonance element of the plurality of resonance elements may be configured to resonate and produce an output signal responsive to incident radiation having a frequency between about a 0.1 THz and 4 THz range. A method of detecting a hazardous material may comprise receiving incident radiation by a focal plane array having a plurality of discrete pixels including a resonance element configured to absorb the incident radiation at a resonant frequency in the THz, generating an output signal from each of the discrete pixels, and determining a presence of a hazardous material by interpreting spectral information from the output signal.

Total-reflection X-ray fluorescence studies of trace elements in biomedical samples

NASA Astrophysics Data System (ADS)

Kubala-Kukuś, A.; Braziewicz, J.; Pajek, M.

2004-08-01

Application of the total-reflection X-ray fluorescence (TXRF) analysis in the studies of trace element contents in biomedical samples is discussed in the following aspects: (i) a nature of trace element concentration distributions, (ii) censoring approach to the detection limits, and (iii) a comparison of two sets of censored data. The paper summarizes the recent results achieved in this topics, in particular, the lognormal, or more general logstable, nature of concentration distribution of trace elements, the random left-censoring and the Kaplan-Meier approach accounting for detection limits and, finally, the application of the logrank test to compare the censored concentrations measured for two groups. These new aspects, which are of importance for applications of the TXRF in different fields, are discussed here in the context of TXRF studies of trace element in various samples of medical interest.

Rotor damage detection by using piezoelectric impedance

NASA Astrophysics Data System (ADS)

Qin, Y.; Tao, Y.; Mao, Y. F.

2016-04-01

Rotor is a core component of rotary machinery. Once the rotor has the damage, it may lead to a major accident. Thus the quantitative rotor damage detection method based on piezoelectric impedance is studied in this paper. With the governing equation of piezoelectric transducer (PZT) in a cylindrical coordinate, the displacement along the radius direction is derived. The charge of PZT is calculated by the electric displacement. Then, by the use of the obtained displacement and charge, an analytic piezoelectric impedance model of the rotor is built. Given the circular boundary condition of a rotor, annular elements are used as the analyzed objects and spectral element method is used to set up the damage detection model. The Electro-Mechanical (E/M) coupled impedance expression of an undamaged rotor is deduced with the application of a low-cost impedance test circuit. A Taylor expansion method is used to obtain the approximate E/M coupled impedance expression for the damaged rotor. After obtaining the difference between the undamaged and damaged rotor impedance, a rotor damage detection method is proposed. This method can directly calculate the change of bending stiffness of the structural elements, it follows that the rotor damage can be effectively detected. Finally, a preset damage configuration is used for the numerical simulation. The result shows that the quantitative damage detection algorithm based on spectral element method and piezoelectric impedance proposed in this paper can identify the location and the severity of the damaged rotor accurately.

Optical Sensors for Biomolecules Using Nanoporous Sol-Gel Materials

NASA Technical Reports Server (NTRS)

Fang, Jonathan; Zhou, Jing C.; Lan, Esther H.; Dunn, Bruce; Gillman, Patricia L.; Smith, Scott M.

2004-01-01

An important consideration for space missions to Mars is the ability to detect biosignatures. Solid-state sensing elements for optical detection of biological entities are possible using sol-gel based biologically active materials. We have used these materials as optical sensing elements in a variety of bioassays, including immunoassays and enzyme assays. By immobilizing an appropriate biomolecule in the sol-gel sensing element, we have successfully detected analytes such as amino acids and hormones. In the case of the amino acid glutamate, the enzyme glutamate dehydrogenase was the immobilized molecule, whereas in the case of the hormone cortisol, an anti-cortisol antibody was immobilized in the sensing element. In this previous work with immobilized enzymes and antibodies, excellent sensitivity and specificity were demonstrated in a variety of formats including bulk materials, thin films and fibers. We believe that the sol-gel approach is an attractive platform for bioastronautics sensing applications because of the ability to detect a wide range of entities such as amino acids, fatty acids, hopanes, porphyrins, etc. The sol-gel approach produces an optically transparent 3D silica matrix that forms around the biomolecule of interest, thus stabilizing its structure and functionality while allowing for optical detection. This encapsulation process protects the biomolecule and leads to a more "rugged" sensor. The nanoporous structure of the sol-gel matrix allows diffusion of small target molecules but keeps larger, biomolecules immobilized in the pores. We are currently developing these biologically active sol-gel materials into small portable devices for on-orbit cortisol detection

Segregation by onset asynchrony.

PubMed

Hancock, P J B; Walton, L; Mitchell, G; Plenderleith, Y; Phillips, W A

2008-08-05

We describe a simple psychophysical paradigm for studying figure-ground segregation by onset asynchrony. Two pseudorandom arrays of Gabor patches are displayed, to left and right of fixation. Within one array, a subset of elements form a figure, such as a randomly curving path, that can only be reliably detected when their onset is not synchronized with that of the background elements. Several findings are reported. First, for most participants, segregation required an onset asynchrony of 20-40 ms. Second, detection was no better when the figure was presented first, and thus by itself, than when the background elements were presented first, even though in the latter case the figure could not be detected in either of the two successive displays alone. Third, asynchrony segregated subsets of randomly oriented elements equally well. Fourth, asynchronous onsets aligned with the path could be discriminated from those lying on the path but not aligned with it. Fifth, both transient and sustained neural activity contribute to detection. We argue that these findings are compatible with neural signaling by synchronized rate codes. Finally, schizophrenic disorganization is associated with reduced sensitivity. Thus, in addition to bearing upon basic theoretical issues, this paradigm may have clinical utility.

Feature Detection and Curve Fitting Using Fast Walsh Transforms for Shock Tracking: Applications

NASA Technical Reports Server (NTRS)

Gnoffo, Peter A.

2017-01-01

Walsh functions form an orthonormal basis set consisting of square waves. Square waves make the system well suited for detecting and representing functions with discontinuities. Given a uniform distribution of 2p cells on a one-dimensional element, it has been proven that the inner product of the Walsh Root function for group p with every polynomial of degree < or = (p - 1) across the element is identically zero. It has also been proven that the magnitude and location of a discontinuous jump, as represented by a Heaviside function, are explicitly identified by its Fast Walsh Transform (FWT) coefficients. These two proofs enable an algorithm that quickly provides a Weighted Least Squares fit to distributions across the element that include a discontinuity. The detection of a discontinuity enables analytic relations to locally describe its evolution and provide increased accuracy. Time accurate examples are provided for advection, Burgers equation, and Riemann problems (diaphragm burst) in closed tubes and de Laval nozzles. New algorithms to detect up to two C0 and/or C1 discontinuities within a single element are developed for application to the Riemann problem, in which a contact discontinuity and shock wave form after the diaphragm bursts.

Oxygen concentration sensor for an internal combustion engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakajima, T.; Okada, Y.; Mieno, T.

1988-09-29

This patent describes an oxygen concentration sensor, comprising: an oxygen ion conductive solid electrolyte member forming a gas diffusion restricted region into which a measuring gas is introduced; a pair of electrodes sandwiching the solid electrolyte member; pump current supply means applying a pump voltage to the pair of electrodes through a current detection element to generate a pump current; and a heater element connected to the solid electrolyte member for heating the solid electrolyte member for heating the solid electrolyte member when a heater current is supplied from a heater current source; wherein the oxygen concentration sensor detects anmore » oxygen concentration in the measuring gas in terms of a current value of the pump current supplied through the current detection element and controls oxygen concentration in the gas diffusion restricted region by conducting oxygen ions through the solid electrolyte member in accordance to the flow of the pump current; and wherein the current detection element is connected to the electrode of the pair of electrodes facing the gas diffusion restricted region for insuring that the current value is representative of the pump current and possible leakage current from the heater current.« less

Finite element simulation of ultrasonic waves in corroded reinforced concrete for early-stage corrosion detection

NASA Astrophysics Data System (ADS)

Tang, Qixiang; Yu, Tzuyang

2017-04-01

In reinforced concrete (RC) structures, corrosion of steel rebar introduces internal stress at the interface between rebar and concrete, ultimately leading to debonding and separation between rebar and concrete. Effective early-stage detection of steel rebar corrosion can significantly reduce maintenance costs and enable early-stage repair. In this paper, ultrasonic detection of early-stage steel rebar corrosion inside concrete is numerically investigated using the finite element method (FEM). Commercial FEM software (ABAQUS) was used in all simulation cases. Steel rebar was simplified and modeled by a cylindrical structure. 1MHz ultrasonic elastic waves were generated at the interface between rebar and concrete. Two-dimensional plain strain element was adopted in all FE models. Formation of surface rust in rebar was modeled by changing material properties and expanding element size in order to simulate the rust interface between rebar and concrete and the presence of interfacial stress. Two types of surface rust (corroded regions) were considered. Time domain and frequency domain responses of displacement were studied. From our simulation result, two corrosion indicators, baseline (b) and center frequency (fc) were proposed for detecting and quantifying corrosion.

Comparative elemental analysis of fine particulate matter (PM2.5) from industrial and residential areas in Greater Cairo-Egypt by means of a multi-secondary target energy dispersive X-ray fluorescence spectrometer

NASA Astrophysics Data System (ADS)

Shaltout, Abdallah A.; Hassan, Salwa K.; Karydas, Andreas G.; Zaki, Z. I.; Mostafa, Nasser Y.; Kregsamer, Peter; Wobrauschek, Peter; Streli, Christina

2018-07-01

Fine aerosol particles with aerodynamic diameter equal or <2.5 μm (PM2.5) have been collected from industrial and residential areas of Greater Cairo, Egypt during two different seasons namely; autumn 2014 and winter 2014/2015. Energy dispersive X-ray fluorescence (EDXRF) analysis utilizing polarization geometry and three different secondary targets (CaF2, Ge, and Mo) was employed for the quantitative analysis of eighteen (18) elements in PM2.5 samples. Light elements like Na and Mg was possible to be quantified, whereas detection limits in the range of few ng m-3 were attained for the most of the detected elements. Although, the average mass concentrations of the PM2.5 collected from the residential area (27 ± 7 μg m-3) is close to the annual mean limit value, a significant number of the collected samples (33%) presented higher average mass concentrations. For the industrial location, the average mass concentration is equal to 55 ± 19 μg m-3, exceeded twofold the annual mean limit value of the European Commission. Remarkably high elemental concentrations were determined for the most of the detected elements from the industrial area samples, clearly indicating the significant influence of anthropogenic activities. The present optimized EDXRF analysis offered significantly improved analytical range and limits of detection with respect to previous similar studies, thus enhancing our knowledge and understanding on the contribution of different pollution sources.

Novel flow cytometric method for the detection of podocalyxin-positive elements in urine of patients with glomerulonephritides - first promising results.

PubMed

Habara, P; Marečková, H; Malíčková, K; Potyšová, Z; Hrušková, Z; Zima, T; Tesař, V

2012-01-01

Glomerulonephritides together create a heterogenic group of supposedly immunologically mediated diseases of glomeruli. They still belong among the most frequent causes of chronic renal failure. Detection of podocytes in urine might serve as an important marker of glomerulonephritides activity. The aim of this study was to develop a novel flow cytometric method for the detection of podocyte fragments and podocytes in urine and assess its possible use in clinical practice. We placed emphasis on the improvement of pre-analytic phase. To suppress the autofluorescence of the background, blocking solutions and magnetic separation were used. An additional surface marker CD10 (nephrilysin) was used together with routinely used podocalyxin (PCX) in order to achieve better identification of podocytes. Based on the surface marker expression, three different element types were identified in the urine samples: PCX+/CD10+ elements (EL) (supposedly podocytes), PCX-/CD10+ EL (supposedly parietal epithelial cells) and PCX+ EL. We examined a total of 36 patients who underwent renal biopsy (non-glomerular nephropathy, MGN, FSGS, IgAN, AAV and MPGN) and 27 healthy controls. Negative results were found in non-glomerular nephropathy and in MGN. In patients with FSGS and IgAN, the levels of urine elements were slightly increased. The highest levels of all elements were found in AAV and MPGN. Our first results suggest that flow cytometric detection may distinguish between glomerular and nonglomerular diseases and that the levels of urine elements might correlate with the degree of glomerular destruction.

Geometric identification and damage detection of structural elements by terrestrial laser scanner

NASA Astrophysics Data System (ADS)

Hou, Tsung-Chin; Liu, Yu-Wei; Su, Yu-Min

2016-04-01

In recent years, three-dimensional (3D) terrestrial laser scanning technologies with higher precision and higher capability are developing rapidly. The growing maturity of laser scanning has gradually approached the required precision as those have been provided by traditional structural monitoring technologies. Together with widely available fast computation for massive point cloud data processing, 3D laser scanning can serve as an efficient structural monitoring alternative for civil engineering communities. Currently most research efforts have focused on integrating/calculating the measured multi-station point cloud data, as well as modeling/establishing the 3D meshes of the scanned objects. Very little attention has been spent on extracting the information related to health conditions and mechanical states of structures. In this study, an automated numerical approach that integrates various existing algorithms for geometric identification and damage detection of structural elements were established. Specifically, adaptive meshes were employed for classifying the point cloud data of the structural elements, and detecting the associated damages from the calculated eigenvalues in each area of the structural element. Furthermore, kd-tree was used to enhance the searching efficiency of plane fitting which were later used for identifying the boundaries of structural elements. The results of geometric identification were compared with M3C2 algorithm provided by CloudCompare, as well as validated by LVDT measurements of full-scale reinforced concrete beams tested in laboratory. It shows that 3D laser scanning, through the established processing approaches of the point cloud data, can offer a rapid, nondestructive, remote, and accurate solution for geometric identification and damage detection of structural elements.

An alpha particle instrument with alpha, proton, and X-ray modes for planetary chemical analyses

NASA Technical Reports Server (NTRS)

Economou, T. E.; Turkevich, A. L.

1976-01-01

The interaction of alpha particles with matter is employed in a compact instrument that could provide rather complete in-situ chemical analyses of surfaces and thin atmospheres of extraterrestrial bodies. The instrument is a miniaturized and improved version of the Surveyor lunar instrument. The backscattering of alpha particles and (alpha, p) reactions provide analytical data on the light elements (carbon-iron). An X-ray mode that detects the photons produced by the alpha sources provides sensitivity and resolution for the chemical elements heavier than about silicon. The X-rays are detected by semiconductor detectors having a resolution between 150 and 250 eV at 5.9 keV. Such an instrument can identify and determine with good accuracy 99 percent of the atoms (except hydrogen) in rocks. For many trace elements, the detecting sensitivity is a few ppm. Auxiliary sources could be used to enhance the sensitivities for elements of special interest. The instrument could probably withstand the acceleration involved in semi-hard landings.

Detecting element specific electrons from a single cobalt nanocluster with synchrotron x-ray scanning tunneling microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kersell, Heath; Shirato, Nozomi; Cummings, Marvin

We use a nanofabricated scanning tunneling microscope tip as a detector to investigate local X-ray induced tunneling and electron emission from a single cobalt nanocluster on a Au(111) surface. The tip-detector is positioned a few angstroms above the nanocluster, and ramping the incident X-ray energy across the Co photoabsorption K-edge enables the detection of element specific electrons. Atomic-scale spatial dependent changes in the X-ray absorption cross section are directly measured by taking the X-ray induced current as a function of X-ray energy. From the measured sample and tip currents, element specific X-ray induced current components can be separated and therebymore » the corresponding yields for the X-ray induced processes of the single cobalt nanocluster can be determined. The detection of element specific synchrotron X-ray induced electrons of a single nanocluster opens a new avenue for materials characterization on a one particle at-a-time basis.« less

Detecting element specific electrons from a single cobalt nanocluster with synchrotron x-ray scanning tunneling microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kersell, Heath; Shirato, Nozomi; Cummings, Marvin

Here, we use a nanofabricated scanning tunneling microscope tip as a detector to investigate local X-ray induced tunneling and electron emission from a single cobalt nanocluster on a Au(111) surface. The tip-detector is positioned a few angstroms above the nanocluster, and ramping the incident X-ray energy across the Co photoabsorption K-edge enables the detection of element specific electrons. Atomic-scale spatial dependent changes in the X-ray absorption cross section are directly measured by taking the X-ray induced current as a function of X-ray energy. From the measured sample and tip currents, element specific X-ray induced current components can be separated andmore » thereby the corresponding yields for the X-ray induced processes of the single cobalt nanocluster can be determined. The detection of element specific synchrotron X-ray induced electrons of a single nanocluster opens a new avenue for materials characterization on a one particle at-a-time basis.« less

Detecting element specific electrons from a single cobalt nanocluster with synchrotron x-ray scanning tunneling microscopy

DOE PAGES

Kersell, Heath; Shirato, Nozomi; Cummings, Marvin; ...

2017-09-05

Here, we use a nanofabricated scanning tunneling microscope tip as a detector to investigate local X-ray induced tunneling and electron emission from a single cobalt nanocluster on a Au(111) surface. The tip-detector is positioned a few angstroms above the nanocluster, and ramping the incident X-ray energy across the Co photoabsorption K-edge enables the detection of element specific electrons. Atomic-scale spatial dependent changes in the X-ray absorption cross section are directly measured by taking the X-ray induced current as a function of X-ray energy. From the measured sample and tip currents, element specific X-ray induced current components can be separated andmore » thereby the corresponding yields for the X-ray induced processes of the single cobalt nanocluster can be determined. The detection of element specific synchrotron X-ray induced electrons of a single nanocluster opens a new avenue for materials characterization on a one particle at-a-time basis.« less

Failure detection in high-performance clusters and computers using chaotic map computations

DOEpatents

Rao, Nageswara S.

2015-09-01

A programmable media includes a processing unit capable of independent operation in a machine that is capable of executing 10.sup.18 floating point operations per second. The processing unit is in communication with a memory element and an interconnect that couples computing nodes. The programmable media includes a logical unit configured to execute arithmetic functions, comparative functions, and/or logical functions. The processing unit is configured to detect computing component failures, memory element failures and/or interconnect failures by executing programming threads that generate one or more chaotic map trajectories. The central processing unit or graphical processing unit is configured to detect a computing component failure, memory element failure and/or an interconnect failure through an automated comparison of signal trajectories generated by the chaotic maps.

Pressure sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mee, David K.; Ripley, Edward B.; Nienstedt, Zachary C.

Disclosed is a passive, in-situ pressure sensor. The sensor includes a sensing element having a ferromagnetic metal and a tension inducing mechanism coupled to the ferromagnetic metal. The tension inducing mechanism is operable to change a tensile stress upon the ferromagnetic metal based on a change in pressure in the sensing element. Changes in pressure are detected based on changes in the magnetic switching characteristics of the ferromagnetic metal when subjected to an alternating magnetic field caused by the change in the tensile stress. The sensing element is embeddable in a closed system for detecting pressure changes without the needmore » for any penetrations of the system for power or data acquisition by detecting changes in the magnetic switching characteristics of the ferromagnetic metal caused by the tensile stress.« less

Tuning the properties of conjugated polyelectrolytes and application in a biosensor platform

DOEpatents

Chen, Liaohai

2004-05-18

The present invention provides a method of detecting a biological agent including contacting a sample with a sensor including a polymer system capable of having an alterable measurable property from the group of luminescence, anisotropy, redox potential and uv/vis absorption, the polymer system including an ionic conjugated polymer and an electronically inert polyelectrolyte having a biological agent recognition element bound thereto, the electronically inert polyelectrolyte adapted for undergoing a conformational structural change upon exposure to a biological agent having affinity for binding to the recognition element bound to the electronically inert polyelectrolyte, and, detecting the detectable change in the alterable measurable property. A chemical moiety being the reaction product of (i) a polyelectrolyte monomer and (ii) a biological agent recognition element-substituted polyelectrolyte monomer is also provided.

Development of a complex of instrumental nuclear-physical methods to detect PGE, Re, Au, and Ag in hard-to-analyze rocks and complex ores

NASA Astrophysics Data System (ADS)

Kolmogorov, Yu. P.; Mezentsev, N. A.; Mironov, A. G.; Parkhomenko, V. S.; Spiridonov, A. M.; Shaporenko, A. D.; Yusupov, T. S.; Zhmodik, S. M.; Zolotarev, K. V.; Anoshin, G. N.

2009-05-01

A system of methods to detect platinum group elements (PGE): Re, Au, and Ag in hard-to-analyze rocks and complex ores has been developed. It applies the SRXRF for Ru, Rh, Pd, and Ag and the INAA method for Os, Ir, Pt and Ag and implies mechanoactivation of probes to study. The results of measurement of standard samples of carbonaceous rocks and ores in order to PGE, gold, and silver confirm the possibility of detecting some of the above-listed elements with a detection limit of 10 ppb.

Optical sensing: recognition elements and devices

NASA Astrophysics Data System (ADS)

Gauglitz, Guenter G.

2012-09-01

The requirements in chemical and biochemical sensing with respect to recognition elements, avoiding non-specific interactions, and high loading of the surface for detection of low concentrations as well as optimized detection systems are discussed. Among the many detection principles the optical techniques are classified. Methods using labeled compounds like Total Internal Reflection Fluorescence (TIRF) and direct optical methods like micro reflectometry or refractometry are discussed in comparison. Reflectometric Interference Spectroscopy (RIfS) is presented as a robust simple method for biosensing. As applications, trace analysis of endocrine disruptors in water, hormones in food, detection of viruses and bacteria in food and clinical diagnostics are discussed.

Detection of highly toxic elements (lead and chromium) in commercially available eyeliner (kohl) using laser induced break down spectroscopy

NASA Astrophysics Data System (ADS)

Gondal, M. A.; Dastageer, M. A.; Al-Adel, F. F.; Naqvi, A. A.; Habibullah, Y. B.

2015-12-01

A sensitive laser induced breakdown spectroscopic system was developed and optimized for using it as a sensor for the detection of trace levels of lead and chromium present in the cosmetic eyeliner (kohl) of different price ranges (brands) available in the local market. Kohl is widely used in developing countries for babies as well adults for beautification as well eyes protection. The atomic transition lines at 405.7 nm and 425.4 nm were used as the marker lines for the detection of lead and chromium respectively. The detection system was optimized by finding the appropriate gate delay between the laser excitation and the data acquisition system and also by achieving optically thin plasma near the target by establishing the local thermodynamic equilibrium condition. The detection system was calibrated for these two hazardous elements and the kohl samples under investigation showed 8-15 ppm by mass of lead and 4-9 ppm by mass of Chromium, which are higher than the safe permissible levels of these elements. The limits of detection of the LIBS system for lead and chromium were found to be 1 and 2 ppm respectively.

Discovery of rare, diagnostic AluYb8/9 elements in diverse human populations.

PubMed

Feusier, Julie; Witherspoon, David J; Scott Watkins, W; Goubert, Clément; Sasani, Thomas A; Jorde, Lynn B

2017-01-01

Polymorphic human Alu elements are excellent tools for assessing population structure, and new retrotransposition events can contribute to disease. Next-generation sequencing has greatly increased the potential to discover Alu elements in human populations, and various sequencing and bioinformatics methods have been designed to tackle the problem of detecting these highly repetitive elements. However, current techniques for Alu discovery may miss rare, polymorphic Alu elements. Combining multiple discovery approaches may provide a better profile of the polymorphic Alu mobilome. Alu Yb8/9 elements have been a focus of our recent studies as they are young subfamilies (~2.3 million years old) that contribute ~30% of recent polymorphic Alu retrotransposition events. Here, we update our ME-Scan methods for detecting Alu elements and apply these methods to discover new insertions in a large set of individuals with diverse ancestral backgrounds. We identified 5,288 putative Alu insertion events, including several hundred novel Alu Yb8/9 elements from 213 individuals from 18 diverse human populations. Hundreds of these loci were specific to continental populations, and 23 non-reference population-specific loci were validated by PCR. We provide high-quality sequence information for 68 rare Alu Yb8/9 elements, of which 11 have hallmarks of an active source element. Our subfamily distribution of rare Alu Yb8/9 elements is consistent with previous datasets, and may be representative of rare loci. We also find that while ME-Scan and low-coverage, whole-genome sequencing (WGS) detect different Alu elements in 41 1000 Genomes individuals, the two methods yield similar population structure results. Current in-silico methods for Alu discovery may miss rare, polymorphic Alu elements. Therefore, using multiple techniques can provide a more accurate profile of Alu elements in individuals and populations. We improved our false-negative rate as an indicator of sample quality for future ME-Scan experiments. In conclusion, we demonstrate that ME-Scan is a good supplement for next-generation sequencing methods and is well-suited for population-level analyses.

Integrating an MR head into a peak detection channel

NASA Astrophysics Data System (ADS)

Curland, Nathan; Machelski, Russell J.

1994-03-01

Integrating a magnetoresistive (MR) head into a peak detection channel requires the engineer to deal with basic differences between MR and thin film heads. These differences result from nonlinear sensor response, separate write and read elements, and having an active element at the air bearing surface (ABS). A simple model for flux superposition can adequately address nonlinear effects and be used for equalization design. Timing budgets can be developed which demonstrate the dominance of media noise for present day systems. Single threshold qualification can handle most current system requirements. Separate read/write elements mean that more attention needs to be paid to offtrack equalization design and head dimensional tolerancing. An active element at the ABS requires better control of the head-disc potential and leakage currents.

Apparatus comprising magnetically actuated valves and uses thereof

DOEpatents

Edwards, Thayne L.; Harper, Jason C.

2016-07-12

The present invention, in part, relates to an apparatus having a single-use, normally-closed fluidic valve that is initially maintained in the closed position by a valve element bonded to an adhesive coating. The valve is opened using a magnetic force. The valve element includes a magnetic material or metal. In some examples, the valve is opened by bringing a magnet in proximity to the valve element to provide a magnetic force that delaminates the valve element from the adhesive coating. In particular, the apparatus can be useful for on-chip amplification and/or detection of various targets, including biological targets and any amplifiable targets. Such apparatuses and methods are useful for in-field or real-time detection of targets, especially in limited resource settings.

FOREWORD: International Summer School for Advanced Studies 'Dynamics of open nuclear systems' (PREDEAL12)

NASA Astrophysics Data System (ADS)

Delion, D. S.; Zamfir, N. V.; Raduta, A. R.; Gulminelli, F.

2013-02-01

This proceedings volume contains the invited lectures and contributions presented at the International Summer School on Nuclear Physics held at Trei Brazi, a summer resort of the Bioterra University, near the city of Predeal, Romania, on 9-20 July 2012. The long tradition of International Summer Schools on Nuclear Physics in Romania dates as far back as 1964, with the event being scheduled every two years. During this period of almost 50 years, many outstanding nuclear scientists have lectured on various topics related to nuclear physics and particle physics. This year we celebrate the 80th birthday of Aureliu Sandulescu, one of the founders of the Romanian school of theoretical nuclear physics. He was Serban Titeica's PhD student, one of Werner Heisenberg's PhD students, and he organized the first edition of this event. Aureliu Sandulescu's major contributions to the field of theoretical nuclear physics are related in particular to the prediction of cluster radioactivity, the physics of open quantum systems and the innovative technique of detecting superheavy nuclei using the double magic projectile 48Ca (Calcium), nowadays a widely used method at the JINR—Dubna and GSI—Darmstadt laboratories. The title of the event, 'Dynamics of Open Nuclear Systems', is in recognition of Aureliu Sandulescu's great personality. The lectures were attended by Romanian and foreign Master and PhD students and young researchers in nuclear physics. About 25 reputable professors and researchers in nuclear physics delivered lectures during this period. According to a well-established tradition, an interval of two hours was allotted for each lecture (including discussions). Therefore we kept a balance between the school and conference format. Two lectures were held during the morning and afternoon sessions. After lecture sessions, three or four oral contributions were given by young scientists. This was a good opportunity for them to present the results of their research in front of renowned professors and researchers in nuclear physics. This proceedings volume is organized into four chapters, which reflects the traditional chapter structure of nuclear physics textbooks, but seen from the perspective of open quantum systems: INuclear structure IIDecay processes IIINuclear reactions and astrophysics IVContributions The lectures and contributions are listed alphabetically by author within each chapter. The volume contains many comprehensive reviews related to the topics of the School. The first week of the School was focused on nuclear structure and decay phenomena, considering the nucleus as an open system. Experts in these fields lectured on cluster radioactivity, the stability of superheavy nuclei, alpha-decay fine structure, fission versus fusion, beta and double beta decay and pairing versus alpha-clustering. New experimental results related to the nuclear stability of low-lying and high spin states were also presented. Recent developments at JINR—Dubna and GSI—Darmstadt international laboratories were also reported by their current or former directors. The second week of the event was dedicated to the physics of exotic nuclei, heavy ion reactions and multi-fragmentation, symmetries and phase transitions of open quantum systems. The stability of the atomic nucleus is an important and always interesting discussion point, especially in the context of newly discovered nuclear systems close to the stability line, such as proton/neutron rich or superheavy nuclei. Several lectures and contributions were focused on nuclear structure models describing low-lying states. This includes the status of density functional theory, new developments in Bohr-Mottelsohn Hamiltonian and shell-model theory, proton-neutron correlations, shape coexistence, back-bending phenomena and the thermodynamics of open quantum systems. Open systems in astrophysics, such as supernovae and neutron stars, were presented in detail by several lecturers. Important topics connected to the status of the equation of state, hyperonic and quark matter and neutrino physics, as well as the applications of nuclear structure in astrophysics, were also on the School's agenda. There were many discussions and questions both during and after presentations. An open and friendly atmosphere characterized our School, although different opinions quite often divided the participants. Many discussions continued during coffee breaks and excursions organized in the beautiful surroundings. We hope that this proceedings volume will be useful for future reference to both young scientists and senior researchers working in various fields of nuclear physics. We cannot end without expressing our many thanks to the National Authority for Scientific Research and the Romanian Academy (Elias Foundation) for their financial support. We acknowledge the Horia Hulubei National Institute of Physics and Nuclear Engineering and Bioterra University for their important contribution in organizing the School. Guest Editors D S Delion, N V Zamfir, A R Raduta and F Gulminelli First Week International Summer School on Nuclear Physics: First Week Second Week International Summer School on Nuclear Physics: Second Week Sponsors Sponsor logoSponsor logoSponsor logoSponsor logoSponsor logo

Micromechanical calorimetric sensor

DOEpatents

Thundat, Thomas G.; Doktycz, Mitchel J.

2000-01-01

A calorimeter sensor apparatus is developed utilizing microcantilevered spring elements for detecting thermal changes within a sample containing biomolecules which undergo chemical and biochemical reactions. The spring element includes a bimaterial layer of chemicals on a coated region on at least one surface of the microcantilever. The chemicals generate a differential thermal stress across the surface upon reaction of the chemicals with an analyte or biomolecules within the sample due to the heat of chemical reactions in the sample placed on the coated region. The thermal stress across the spring element surface creates mechanical bending of the microcantilever. The spring element has a low thermal mass to allow detection and measuring of heat transfers associated with chemical and biochemical reactions within a sample placed on or near the coated region. A second surface may have a different material, or the second surface and body of microcantilever may be of an inert composition. The differential thermal stress between the surfaces of the microcantilever create bending of the cantilever. Deflections of the cantilever are detected by a variety of detection techniques. The microcantilever may be approximately 1 to 200 .mu.m long, approximately 1 to 50 .mu.m wide, and approximately 0.3 to 3.0 .mu.m thick. A sensitivity for detection of deflections is in the range of 0.01 nanometers. The microcantilever is extremely sensitive to thermal changes in samples as small as 30 microliters.

G-Quadruplex-based DNAzyme for colorimetric detection of cocaine: using magnetic nanoparticles as the separation and amplification element.

PubMed

Du, Yan; Li, Bingling; Guo, Shaojun; Zhou, Zhixue; Zhou, Ming; Wang, Erkang; Dong, Shaojun

2011-02-07

The appearance of the aptamer provides good recognition elements for small molecules, especially for drugs. In this work, by combining the advantages of magnetic nanoparticles (MNPs) with colorimetric drug detection using hemin-G-quadruplex complex as the sensing element, we report a simple and sensitive DNAzyme-based colorimetric sensor for cocaine detection in a 3,3,5,5-tetramethylbenzidine sulfate (TMB)-H(2)O(2) reaction system. The whole experimental processes are simplified. Cocaine aptamer fragments, SH-C2, are covalently labeled onto the amine-functionalized MNPs. When the target cocaine and another cocaine aptamer fragments (C1) grafted with G-riched strand AG4 (i.e. C1-AG4) are present simultaneously, the C2 layer on MNPs hybridizes partly with C1-AG4 to bind the cocaine. The C1-AG4 can be combinded with hemin to form DNAzyme which can effectively catalyze the H(2)O(2)-mediated oxidation of TMB, giving rise to a change in solution color. Importantly, using MNPs as the separation and amplification elements could effectively reduce the background signal and the interference from the real samples. A linear response from 0.1 μM to 20 μM is obtained for cocaine and a detection limit of 50 nM is achieved, which provides high sensitivity and selectivity to detect cocaine.

Rapid screening of heavy metals and trace elements in environmental samples using portable X-ray fluorescence spectrometer, A comparative study

PubMed Central

McComb, Jacqueline Q.; Rogers, Christian; Han, Fengxiang X.; Tchounwou, Paul B.

2014-01-01

With industrialization, great amounts of trace elements and heavy metals have been excavated and released on the surface of the earth and dissipated into the environments. Rapid screening technology for detecting major and trace elements as well as heavy metals in variety of environmental samples is most desired. The objectives of this study were to determine the detection limits, accuracy, repeatability and efficiency of a X-ray fluorescence spectrometer (Niton XRF analyzer) in comparison with the traditional analytical methods, inductively coupled plasma optical emission spectrometer (ICP-OES) and inductively coupled plasma optical emission spectrometer (ICP-MS) in screening of major and trace elements of environmental samples including estuary soils and sediments, contaminated soils, and biological samples. XRF is a fast and non-destructive method in measuring the total concentration of multi--elements simultaneously. Contrary to ICP-OES and ICP-MS, XRF analyzer is characterized by the limited preparation required for solid samples, non-destructive analysis, increased total speed and high throughout, the decreased production of hazardous waste and the low running costs as well as multi-elemental determination and portability in the fields. The current comparative study demonstrates that XRF is a good rapid non-destructive method for contaminated soils, sediments and biological samples containing higher concentrations of major and trace elements. Unfortunately, XRF does not have sensitive detection limits of most major and trace elements as ICP-OES or ICP-MS but it may serve as a rapid screening tool for locating hot spots of uncontaminated field soils and sediments. PMID:25861136

Detecting authorized and unauthorized genetically modified organisms containing vip3A by real-time PCR and next-generation sequencing.

PubMed

Liang, Chanjuan; van Dijk, Jeroen P; Scholtens, Ingrid M J; Staats, Martijn; Prins, Theo W; Voorhuijzen, Marleen M; da Silva, Andrea M; Arisi, Ana Carolina Maisonnave; den Dunnen, Johan T; Kok, Esther J

2014-04-01

The growing number of biotech crops with novel genetic elements increasingly complicates the detection of genetically modified organisms (GMOs) in food and feed samples using conventional screening methods. Unauthorized GMOs (UGMOs) in food and feed are currently identified through combining GMO element screening with sequencing the DNA flanking these elements. In this study, a specific and sensitive qPCR assay was developed for vip3A element detection based on the vip3Aa20 coding sequences of the recently marketed MIR162 maize and COT102 cotton. Furthermore, SiteFinding-PCR in combination with Sanger, Illumina or Pacific BioSciences (PacBio) sequencing was performed targeting the flanking DNA of the vip3Aa20 element in MIR162. De novo assembly and Basic Local Alignment Search Tool searches were used to mimic UGMO identification. PacBio data resulted in relatively long contigs in the upstream (1,326 nucleotides (nt); 95 % identity) and downstream (1,135 nt; 92 % identity) regions, whereas Illumina data resulted in two smaller contigs of 858 and 1,038 nt with higher sequence identity (>99 % identity). Both approaches outperformed Sanger sequencing, underlining the potential for next-generation sequencing in UGMO identification.

New SSMS Techniques for the Determination of Rhodium and Other Platinum- Group Elements in Carbonaceous Chondrites

NASA Astrophysics Data System (ADS)

Jochum, K. P.; Seufert, H. M.

1995-09-01

We have developed new spark source mass spectrometric (SSMS) techniques for simultaneous analysis of platinum-group elements (PGE) together with other trace elements in stony meteorites. We have measured elemental abundances of Rh, Ru, Os, Ir, Pt, Au in carbonaceous chondrites of different types including the two CI chondrites Orgueil and Ivuna. These data are relevant for the determination of solar-system abundances. Whereas the solar-system abundances of most PGE are well known, this is not the case for Rh, and no literature data exist for carbonaceous chondrites, mainly because of analytical difficulties. The SSMS techniques include new calibration procedures and the use of a recently developed multi-ion counting (MIC) system [1]. The mono-isotopic element Rh and the other PGE were determined by using internal standard elements (e.g., Nd, U) that were measured by isotope dilution in the same sample electrode material. The data were calibrated with certified standard solutions of PGE which were doped on trace-element poor rock samples. Ion abundances were measured using both the conventional photoplate detection and the ion-counting techniques. The new MIC technique that uses up to 20 small channeltrons for ion counting measurements has the advantage of improved precision, detection limits and analysis time compared to photoplate detection. Tab. 1 shows the Rh analyses for the meteorites Orgueil, Ivuna, Murchison, Allende and Karoonda obtained by conventional photoplate detection. These are the first Rh results for carbonaceous chondrites. The data for the two CI chondrites Orgueil and Ivuna are identical and agree within 4 % with the CI estimate of Anders and Grevesse [2] which was derived indirectly from analyses for H-chondrites. The PGE Os, Ir, Pt, Au and W, Re, Th, U concentrations were determined by both detection systems. Data obtained with the MIC system are more precise (about 4% for concentrations in the ppb range) compared to the photoplate detection system (about 10 - 15 %). Both data sets agree within error limits. Rhodium correlates well with Pt and other PGE indicating no significant fractionation between the different types of carbonaceous chondrites (Tab. 1). References: [1] Jochum K. P. et al. (1994) Fresenius J. Anal. Chem., 350, 642-644. [2] Anders E. and Grevesse N. (1989) GCA, 53, 197-214.

Characterization of Group V Dubnium Homologs on DGA Extraction Chromatography Resin from Nitric and Hydrofluoric Acid Matrices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Despotopulos, J D; Sudowe, R

2012-02-21

Studies of the chemical properties of superheavy elements (SHE) pose interesting challenges due to their short half-lives and low production rates. Chemical systems must have extremely fast kinetics, fast enough kinetics to be able to examine the chemical properties of interest before the SHE decays to another nuclide. To achieve chemistry on such time scales, the chemical system must also be easily automated. Most importantly however, a chemical system must be developed which provides suitable separation and kinetics before an on-line study of a SHE can be performed. Relativistic effects make studying the chemical properties of SHEs interesting due tomore » the impact these effects could have on the SHEs chemical properties. Relativistic effects arise when the velocity of the s orbital electrons approach the speed of light. As this velocity increases, the Bohr radius of the inner electron orbitals decreases and there is an increase in the particles mass. This contraction results in a destabilization of the energy of the outer d and f electron orbitals (5f and 6d in the case of SHE), which can cause these to expand due to their increased shielding from the nuclear charge. Another relativistic effect is the spin-orbit splitting for p, d, and f orbitals into j = 1 {+-} 1/2 states. This can lead most interestingly to a possible increased stability of element 114, which due to large spin-orbit splitting of the 7p orbital and the relativistically stabilized 7p{sub 1/2} and 7s orbital gives rise to a closed shell ground state of 7s{sup 2}7p{sub 1/2}{sup 2}. The homologs of element 105, dubnium (Db), Ta and Nb and the pseudo-homolog Pa, are well known to hydrolyze and form both neutral and non-neutral monoatomic and polyatomic species that may cause issues with extraction from a given chemical system. Early ion-exchange and solvent-extraction studies show mixed results for the behavior of Db. Some studies show Db behaving most similar to Ta, while others show it behaving somewhere between Nb and Pa. Much more recent studies have examined the properties of Db from HNO{sub 3}/HF matrices, and suggest Db forms complexes similar to those of Pa. Very little experimental work into the behavior of element 114 has been performed. Thermochromatography experiments of three atoms of element 114 indicate that the element 114 is at least as volatile as Hg, At, and element 112. Lead was shown to deposit on gold at temperatures about 1000 C higher than the atoms of element 114. Results indicate a substantially increased stability of element 114. No liquid phase studies of element 114 or its homologs (Pb, Sn, Ge) or pseudo-homologs (Hg, Cd) have been performed. Theoretical predictions indicate that element 114 is should have a much more stable +2 oxidation state and neutral state than Pb, which would result in element 114 being less reactive and less metallic than Pb. The relativistic effects on the 7p{sub 1/2} electrons are predicted to cause a diagonal relationship to be introduced into the periodic table. Therefore, 114{sup 2+} is expected to behave as if it were somewhere between Hg{sup 2+}, Cd{sup 2+}, and Pb{sup 2+}. In this work two commercially available extraction chromatography resins are evaluated, one for the separation of Db homologs and pseudo?homologs from each other as well as from potential interfering elements such as Group IV Rf homologs and actinides, and the other for separation of element 114 homologs. One resin, Eichrom's DGA resin, contains a N,N,N',N'-tetra-n-octyldiglycolamide extractant, which separates analytes based on both size and charge characteristics of the solvated metal species, coated on an inert support. The DGA resin was examined for Db chemical systems, and shows a high degree of selectivity for tri-, tetra-, and hexavalent metal ions in multiple acid matrices with fast kinetics. The other resin, Eichrom's Pb resin, contains a di-t-butylcyclohexano 18-crown-6 extractant with isodecanol solvent, which separates analytes based on steric interactions between the cavity of the crown ether and electrostatic interactions between the oxygen's of the ether and cations in the mobile phase. This particular resin has been shown to have an extremely high uptake affinity for Pb, a direct homolog of element 114, and is thus a good initial extractant to examine for a potential element 114 chemical system. Figure 1.1 shows the respective extractant molecules from the DGA and Pb resins. Batch uptake experiments were conducted to examine the uptake behavior of Ta on the DGA resin. Batch uptake experiments were also conducted to examine the uptake behavior of Ge on the Pb resin. Column experiments were designed based on batch uptake experiments of Ta, Am, Pa, Np, Zr, and Nb to establish a sequential extraction of Group IV/V homologs as well as Am for potential use as a Db chemical system.« less

Detection of system failures in multi-axes tasks. [pilot monitored instrument approach

NASA Technical Reports Server (NTRS)

Ephrath, A. R.

1975-01-01

The effects of the pilot's participation mode in the control task on his workload level and failure detection performance were examined considering a low visibility landing approach. It is found that the participation mode had a strong effect on the pilot's workload, the induced workload being lowest when the pilot acted as a monitoring element during a coupled approach and highest when the pilot was an active element in the control loop. The effects of workload and participation mode on failure detection were separated. The participation mode was shown to have a dominant effect on the failure detection performance, with a failure in a monitored (coupled) axis being detected significantly faster than a comparable failure in a manually controlled axis.

Development of an adaptive failure detection and identification system for detecting aircraft control element failures

NASA Technical Reports Server (NTRS)

Bundick, W. Thomas

1990-01-01

A methodology for designing a failure detection and identification (FDI) system to detect and isolate control element failures in aircraft control systems is reviewed. An FDI system design for a modified B-737 aircraft resulting from this methodology is also reviewed, and the results of evaluating this system via simulation are presented. The FDI system performed well in a no-turbulence environment, but it experienced an unacceptable number of false alarms in atmospheric turbulence. An adaptive FDI system, which adjusts thresholds and other system parameters based on the estimated turbulence level, was developed and evaluated. The adaptive system performed well over all turbulence levels simulated, reliably detecting all but the smallest magnitude partially-missing-surface failures.

Alien liquid detector and control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Potter, B.M.

An alien liquid detector employs a monitoring element and an energizing circuit for maintaining the temperature of the monitoring element substantially above ambient temperature. For this purpose an electronic circit controls a flow of heating current to the monitoring element. The presence of an alien liquid is detected by sensing a predetermined change in heating current flow to the monitoring element, e.g., to distinguish between water and oil. In preferred embodiments the monitoring element is a thermistor whose resistance is compared with a reference resistance and heating current through the thermistor is controlled in accordance with the difference. In onemore » embodiment a bridge circuit senses the resistance difference; the difference may be sensed by an operational amplifier arrangement. Features of the invention include positioning the monitoring element at the surface of water, slightly immersed, so that the power required to maintain the thermistor temperature substantially above ambient temperature serves to detect presence of oil pollution at the surface.« less

[Determination and principal component analysis of mineral elements based on ICP-OES in Nitraria roborowskii fruits from different regions].

PubMed

Yuan, Yuan-Yuan; Zhou, Yu-Bi; Sun, Jing; Deng, Juan; Bai, Ying; Wang, Jie; Lu, Xue-Feng

2017-06-01

The content of elements in fifteen different regions of Nitraria roborowskii samples were determined by inductively coupled plasma-atomic emission spectrometry(ICP-OES), and its elemental characteristics were analyzed by principal component analysis. The results indicated that 18 mineral elements were detected in N. roborowskii of which V cannot be detected. In addition, contents of Na, K and Ca showed high concentration. Ti showed maximum content variance, while K is minimum. Four principal components were gained from the original data. The cumulative variance contribution rate is 81.542% and the variance contribution of the first principal component was 44.997%, indicating that Cr, Fe, P and Ca were the characteristic elements of N. roborowskii.Thus, the established method was simple, precise and can be used for determination of mineral elements in N.roborowskii Kom. fruits. The elemental distribution characteristics among N.roborowskii fruits are related to geographical origins which were clearly revealed by PCA. All the results will provide good basis for comprehensive utilization of N.roborowskii. Copyright© by the Chinese Pharmaceutical Association.

Whole-body concentrations of elements in three fish species from offshore oil platforms and natural areas in the Southern California Bight, USA

USGS Publications Warehouse

Love, Milton S.; Saiki, Michael K.; May, Thomas W.; Yee, Julie L.

2013-01-01

elements. Forty-two elements were excluded from statistical comparisons as they (1) consisted of major cations that were unlikely to accumulate to potentially toxic concentrations; (2) were not detected by the analytical procedures; or (3) were detected at concentrations too low to yield reliable quantitative measurements. The remaining 21 elements consisted of aluminum, arsenic, barium, cadmium, chromium, cobalt, copper, gallium, iron, lead, lithium, manganese, mercury, nickel, rubidium, selenium, strontium, tin, titanium, vanadium, and zinc. Statistical comparisons of these elements indicated that none consistently exhibited higher concentrations at oil platforms than at natural areas. However, the concentrations of copper, selenium, titanium, and vanadium in Pacific sanddab were unusual because small individuals exhibited either no differences between oil platforms and natural areas or significantly lower concentrations at oil platforms than at natural areas, whereas large individuals exhibited significantly higher concentrations at oil platforms than at natural areas.

Uncoupling of sgRNAs from their associated barcodes during PCR amplification of combinatorial CRISPR screens

PubMed Central

2018-01-01

Many implementations of pooled screens in mammalian cells rely on linking an element of interest to a barcode, with the latter subsequently quantitated by next generation sequencing. However, substantial uncoupling between these paired elements during lentiviral production has been reported, especially as the distance between elements increases. We detail that PCR amplification is another major source of uncoupling, and becomes more pronounced with increased amounts of DNA template molecules and PCR cycles. To lessen uncoupling in systems that use paired elements for detection, we recommend minimizing the distance between elements, using low and equal template DNA inputs for plasmid and genomic DNA during PCR, and minimizing the number of PCR cycles. We also present a vector design for conducting combinatorial CRISPR screens that enables accurate barcode-based detection with a single short sequencing read and minimal uncoupling. PMID:29799876

In Vitro Selection of a Single-Stranded DNA Molecular Recognition Element against the Pesticide Fipronil and Sensitive Detection in River Water

PubMed Central

Sooter, Letha J.

2017-01-01

Fipronil is a commonly used insecticide that has been shown to have environmental and human health risks. The current standard methods of detection for fipronil and its metabolites, such as GC-MS, are time consuming and labor intensive. In this study, a variant of systematic evolution of ligands by exponential enrichment (SELEX), was utilized to identify the first single-stranded DNA (ssDNA) molecular recognition element (MRE) that binds to fipronil with high affinity (Kd = 48 ± 8 nM). The selected MRE displayed low cross binding activity on various environmentally relevant, structurally unrelated herbicides and pesticides, in addition to broad-spectrum binding activity on major metabolites of fipronil and a structurally similar pesticide in prepared river samples. Additionally, a proof-of-principle fluorescent detection assay was developed by using the selected ssDNA MRE as a signal-reporting element, with a limit of detection of 105 nM in a prepared river water sample. PMID:29283416

A Miniaturized On-Chip Colorimeter for Detecting NPK Elements

PubMed Central

Liu, Rui-Tao; Tao, Lu-Qi; Liu, Bo; Tian, Xiang-Guang; Mohammad, Mohammad Ali; Yang, Yi; Ren, Tian-Ling

2016-01-01

Recently, precision agriculture has become a globally attractive topic. As one of the most important factors, the soil nutrients play an important role in estimating the development of precision agriculture. Detecting the content of nitrogen, phosphorus and potassium (NPK) elements more efficiently is one of the key issues. In this paper, a novel chip-level colorimeter was fabricated to detect the NPK elements for the first time. A light source–microchannel photodetector in a sandwich structure was designed to realize on-chip detection. Compared with a commercial colorimeter, all key parts are based on MEMS (Micro-Electro-Mechanical System) technology so that the volume of this on-chip colorimeter can be minimized. Besides, less error and high precision are achieved. The cost of this colorimeter is two orders of magnitude less than that of a commercial one. All these advantages enable a low-cost and high-precision sensing operation in a monitoring network. The colorimeter developed herein has bright prospects for environmental and biological applications. PMID:27527177

A Miniaturized On-Chip Colorimeter for Detecting NPK Elements.

PubMed

Liu, Rui-Tao; Tao, Lu-Qi; Liu, Bo; Tian, Xiang-Guang; Mohammad, Mohammad Ali; Yang, Yi; Ren, Tian-Ling

2016-08-04

Recently, precision agriculture has become a globally attractive topic. As one of the most important factors, the soil nutrients play an important role in estimating the development of precision agriculture. Detecting the content of nitrogen, phosphorus and potassium (NPK) elements more efficiently is one of the key issues. In this paper, a novel chip-level colorimeter was fabricated to detect the NPK elements for the first time. A light source-microchannel photodetector in a sandwich structure was designed to realize on-chip detection. Compared with a commercial colorimeter, all key parts are based on MEMS (Micro-Electro-Mechanical System) technology so that the volume of this on-chip colorimeter can be minimized. Besides, less error and high precision are achieved. The cost of this colorimeter is two orders of magnitude less than that of a commercial one. All these advantages enable a low-cost and high-precision sensing operation in a monitoring network. The colorimeter developed herein has bright prospects for environmental and biological applications.

Advances in SAW gas sensors based on the condensate-adsorption effect.

PubMed

Liu, Jiuling; Wang, Wen; Li, Shunzhou; Liu, Minghua; He, Shitang

2011-01-01

A surface-acoustic-wave (SAW) gas sensor with a low detection limit and fast response for volatile organic compounds (VOCs) based on the condensate-adsorption effect detection is developed. In this sensor a gas chromatography (GC) column acts as the separator element and a dual-resonator oscillator acts as the detector element. Regarding the surface effective permittivity method, the response mechanism analysis, which relates the condensate-adsorption effect, is performed, leading to the sensor performance prediction prior to fabrication. New designs of SAW resonators, which act as feedback of the oscillator, are devised in order to decrease the insertion loss and to achieve single-mode control, resulting in superior frequency stability of the oscillator. Based on the new phase modulation approach, excellent short-term frequency stability (±3 Hz/s) is achieved with the SAW oscillator by using the 500 MHz dual-port resonator as feedback element. In a sensor experiment investigating formaldehyde detection, the implemented SAW gas sensor exhibits an excellent threshold detection limit as low as 0.38 pg.

Distributed fiber optic sensor-enhanced detection and prediction of shrinkage-induced delamination of ultra-high-performance concrete overlay

NASA Astrophysics Data System (ADS)

Bao, Yi; Valipour, Mahdi; Meng, Weina; Khayat, Kamal H.; Chen, Genda

2017-08-01

This study develops a delamination detection system for smart ultra-high-performance concrete (UHPC) overlays using a fully distributed fiber optic sensor. Three 450 mm (length) × 200 mm (width) × 25 mm (thickness) UHPC overlays were cast over an existing 200 mm thick concrete substrate. The initiation and propagation of delamination due to early-age shrinkage of the UHPC overlay were detected as sudden increases and their extension in spatial distribution of shrinkage-induced strains measured from the sensor based on pulse pre-pump Brillouin optical time domain analysis. The distributed sensor is demonstrated effective in detecting delamination openings from microns to hundreds of microns. A three-dimensional finite element model with experimental material properties is proposed to understand the complete delamination process measured from the distributed sensor. The model is validated using the distributed sensor data. The finite element model with cohesive elements for the overlay-substrate interface can predict the complete delamination process.

Board of Regents of the Nevada System of Higher Education, on behalf of the University of Nevada, Reno

DOEpatents

Adams, Jesse D.; Sulchek, Todd A.; Feigin, Stuart C.

2017-07-11

A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

Measuring the content of 17 elements in the flesh of Prunus cerasifera and its cultivars by ICP-MS.

PubMed

Shen, Jing; Xue, Hai-Yan; Li, Gai-Ru; Lu, Yi; Yao, Jun

2014-09-01

The present study compared the contents of inorganic elements in the pulp of purple, red, and yellow Prunus cerasifera with its cultivars. A method was established for the analysis of 17 kinds of trace elements (K, Ca, Mg, Na, Fe, Mn, Cu, Zn, Be, Li, Se, Sr, Cr, Pb, Cd, As and Hg) in the flesh of Prunus cerasifera by microwave digestion-ICP-MS. The detection method is simple and quick, yet shoes high precision and high sensitivity. The recovery rate of 17 elements ranged, from 93.5% to 110.4%. The analysis results showed that the contents of 17 elements in the flesh of purple, red, and yellow Prunus cerasifera and its cultivars are similar, containing extremely rich K elements (as high as 1 per thousand) and higher contents of Ca, Mg, Na, Fe and Mn. The contents of Cu, Zn, Li, Se, Sr and Cr are also present. The contents of Pb, Cd, As, Hg and other harmful element are either very low or not detectable. The experimental results for the study of trace elements in pulp of Prunus cerasifera and its cultivars provide empirical data for. future research in this area.

A novel vacuum spectrometer for total reflection x-ray fluorescence analysis with two exchangeable low power x-ray sources for the analysis of low, medium, and high Z elements in sequence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wobrauschek, P., E-mail: wobi@ati.ac.at; Prost, J.; Ingerle, D.

2015-08-15

The extension of the detectable elemental range with Total Reflection X-ray Fluorescence (TXRF) analysis is a challenging task. In this paper, it is demonstrated how a TXRF spectrometer is modified to analyze elements from carbon to uranium. Based on the existing design of a vacuum TXRF spectrometer with a 12 specimen sample changer, the following components were renewed: the silicon drift detector with 20 mm{sup 2} active area and having a special ultra-thin polymer window allowing the detection of elements from carbon upwards. Two exchangeable X-ray sources guarantee the efficient excitation of both low and high Z elements. These X-raymore » sources were two light-weighted easily mountable 35 W air-cooled low-power tubes with Cr and Rh anodes, respectively. The air cooled tubes and the Peltier-cooled detector allowed to construct a transportable tabletop spectrometer with compact dimensions, as neither liquid nitrogen cooling for the detector nor a water cooling circuit and a bulky high voltage generator for the X-ray tubes are required. Due to the excellent background conditions as a result of the TXRF geometry, detection limits of 150 ng for C, 12 ng for F, and 3.3 ng for Na have been obtained using Cr excitation in vacuum. For Rh excitation, the detection limits of 90 pg could be achieved for Sr. Taking 10 to 20 μl of sample volume, extrapolated detection limits in the ng/g (ppb) range are resulting in terms of concentration.« less

Nanoparticle-Functionalized Porous Polymer Monolith Detection Elements for Surface-Enhanced Raman Scattering

PubMed Central

Liu, Jikun; White, Ian; DeVoe, Don L.

2011-01-01

The use of porous polymer monoliths functionalized with silver nanoparticles is introduced in this work for high-sensitivity surface-enhanced Raman scattering (SERS) detection. Preparation of the SERS detection elements is a simple process comprising the synthesis of a discrete polymer monolith section within a silica capillary, followed by physically trapping silver nanoparticle aggregates within the monolith matrix. A SERS detection limit of 220 fmol for Rhodamine 6G (R6G) is demonstrated, with excellent signal stability over a 24 h period. The capability of the SERS-active monolith for label-free detection of biomolecules was demonstrated by measurements of bradykinin and cyctochrome c. The SERS-active monoliths can be readily integrated into miniaturized micro-total-analysis systems for on-line and label-free detection for a variety of biosensing, bioanalytical, and biomedical applications. PMID:21322579

Laboratory evaluation of a field-portable sealed source X-ray fluorescence spectrometer for determination of metals in air filter samples.

PubMed

Lawryk, Nicholas J; Feng, H Amy; Chen, Bean T

2009-07-01

Recent advances in field-portable X-ray fluorescence (FP XRF) spectrometer technology have made it a potentially valuable screening tool for the industrial hygienist to estimate worker exposures to airborne metals. Although recent studies have shown that FP XRF technology may be better suited for qualitative or semiquantitative analysis of airborne lead in the workplace, these studies have not extensively addressed its ability to measure other elements. This study involved a laboratory-based evaluation of a representative model FP XRF spectrometer to measure elements commonly encountered in workplace settings that may be collected on air sample filter media, including chromium, copper, iron, manganese, nickel, lead, and zinc. The evaluation included assessments of (1) response intensity with respect to location on the probe window, (2) limits of detection for five different filter media, (3) limits of detection as a function of analysis time, and (4) bias, precision, and accuracy estimates. Teflon, polyvinyl chloride, polypropylene, and mixed cellulose ester filter media all had similarly low limits of detection for the set of elements examined. Limits of detection, bias, and precision generally improved with increasing analysis time. Bias, precision, and accuracy estimates generally improved with increasing element concentration. Accuracy estimates met the National Institute for Occupational Safety and Health criterion for nearly all the element and concentration combinations. Based on these results, FP XRF spectrometry shows potential to be useful in the assessment of worker inhalation exposures to other metals in addition to lead.

Holographic elements and curved slit used to enlarge field of view in rocket detection system

NASA Astrophysics Data System (ADS)

Breton, Mélanie; Fortin, Jean; Lessard, Roger A.; Châteauneuf, Marc

2006-09-01

Rocket detection over a wide field of view is an important issue in the protection of light armored vehicle. Traditionally, the detection occurs in UV band, but recent studies have shown the existence of significant emission peaks in the visible and near infrared at rocket launch time. The use of the visible region is interesting in order to reduce the weight and cost of systems. Current methods to detect those specific peaks involve use of interferometric filters. However, they fail to combine wide angle with wavelength selectivity. A linear array of volume holographic elements combined with a curved exit slit is proposed for the development of a wide field of view sensor for the detection of solid propellant motor launch flash. The sensor is envisaged to trigger an active protection system. On the basis of geometric theory, a system has been designed. It consists of a collector, a linear array of holographic elements, a curved slit and a detector. The collector is an off-axis parabolic mirror. Holographic elements are recorded subdividing a hologram film in regions, each individually exposed with a different incidence angle. All regions have a common diffraction angle. The incident angle determines the instantaneous field of view of the elements. The volume hologram performs the function of separating and focusing the diffracted beam on an image plane to achieve wavelength filtering. Conical diffraction property is used to enlarge the field of view in elevation. A curved slit was designed to correspond to oblique incidence of the holographic linear array. It is situated at the image plane and filters the diffracted spectrum toward the sensor. The field of view of the design was calculated to be 34 degrees. This was validated by a prototype tested during a field trial. Results are presented and analyzed. The system succeeded in detecting the rocket launch flash at desired fields of view.

Hiding an elephant: heavy sterile neutrino with large mixing angle does not contradict cosmology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bezrukov, F.; Chudaykin, A.; Gorbunov, D., E-mail: Fedor.Bezrukov@manchester.ac.uk, E-mail: chudy@ms2.inr.ac.ru, E-mail: gorby@ms2.inr.ac.ru

We study a model of a keV-scale sterile neutrino with a relatively large mixing with the Standard Model sector. Usual considerations predict active generation of such particles in the early Universe, which leads to constraints from the total Dark Matter density and absence of X-ray signal from sterile neutrino decay. These bounds together may deem any attempt of creation of the keV scale sterile neutrino in the laboratory unfeasible. We argue that for models with a hidden sector coupled to the sterile neutrino these bounds can be evaded, opening new perspectives for the direct studies at neutrino experiments such asmore » Troitsk ν-mass and KATRIN. We estimate the generation of sterile neutrinos in scenarios with the hidden sector dynamics keeping the sterile neutrinos either massless or superheavy in the early Universe. In both cases the generation by oscillations from active neutrinos in plasma is suppressed.« less

Fission Barrier of ^254No at High Spin

NASA Astrophysics Data System (ADS)

Henning, G.; Khoo, T. L.; Seweryniak, D.; Back, B. B.; Bertone, P. F.; Carpenter, M. P.; Greene, J. P.; Gürdal, G.; Hoffman, C. R.; Janssens, R. V. F.; Kay, B. P.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; McCutchan, E. A.; Nair, C.; Rogers, A. M.; Zhu, S.; Chiara, C. J.; Hauschild, K.; Lopez-Martens, A.; Heinz, A.; Piot, J.; Chowdhury, P.; Lakshmi, S.

2010-11-01

Superheavy nuclei provide opportunities to study nuclear structure at the limits in charge, spin and excitation energy. These nuclei exist only because shell effects create a fission barrier Bf. Hence, it is important to determine Bf and its spin dependence. For ^254No, the maximum spin and energy were found [1] to be Imax= 22 and E* = 8 MeV in the reaction ^208Pb(^48Ca,2n) at a beam energy of 219 MeV. At 223 MeV, the maximum spin increases to 32. In contrast, the spin in ^220Th, produced [2] in the ^176Yb(^48 Ca,4n) reaction at 206 and 219 MeV, saturates at 20. A measurement of the entry distribution of ^254No at 223 MeV has been performed to determine Bf(I) and results will be reported.[4pt] [1] P. Reiter et al., Phys. Rev. Lett. 84, 3542 (2000).[0pt] [2] A. Heinz et al., Nucl. Phys. A682, 458c (2001)

Deformation-induced splitting of the isoscalar E 0 giant resonance: Skyrme random-phase-approximation analysis

NASA Astrophysics Data System (ADS)

Kvasil, J.; Nesterenko, V. O.; Repko, A.; Kleinig, W.; Reinhard, P.-G.

2016-12-01

The deformation-induced splitting of isoscalar giant monopole resonance (ISGMR) is systematically analyzed in a wide range of masses covering medium, rare-earth, actinide, and superheavy axial deformed nuclei. The study is performed within the fully self-consistent quasiparticle random-phase-approximation method based on the Skyrme functional. Two Skyrme forces, one with a large (SV-bas) and one with a small (SkP) nuclear incompressibility, are considered. The calculations confirm earlier results that, because of the deformation-induced E 0 -E 2 coupling, the isoscalar E 0 resonance attains a double-peak structure and significant energy upshift. Our results are compared with available analytic estimations. Unlike earlier studies, we get a smaller energy difference between the lower and upper peaks and thus a stronger E 0 -E 2 coupling. This in turn results in more pumping of E 0 strength into the lower peak and more pronounced splitting of ISGMR. We also discuss widths of the peaks and their negligible correlation with deformation.

Systematics of capture and fusion dynamics in heavy-ion collisions

NASA Astrophysics Data System (ADS)

Wang, Bing; Wen, Kai; Zhao, Wei-Juan; Zhao, En-Guang; Zhou, Shan-Gui

2017-03-01

We perform a systematic study of capture excitation functions by using an empirical coupled-channel (ECC) model. In this model, a barrier distribution is used to take effectively into account the effects of couplings between the relative motion and intrinsic degrees of freedom. The shape of the barrier distribution is of an asymmetric Gaussian form. The effect of neutron transfer channels is also included in the barrier distribution. Based on the interaction potential between the projectile and the target, empirical formulas are proposed to determine the parameters of the barrier distribution. Theoretical estimates for barrier distributions and calculated capture cross sections together with experimental cross sections of 220 reaction systems with 182 ⩽ZPZT ⩽ 1640 are tabulated. The results show that the ECC model together with the empirical formulas for parameters of the barrier distribution work quite well in the energy region around the Coulomb barrier. This ECC model can provide prediction of capture cross sections for the synthesis of superheavy nuclei as well as valuable information on capture and fusion dynamics.

Universal Charge-Radius Relation for Subatomic and Astrophysical Compact Objects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Madsen, Jes

2008-04-18

Electron-positron pair creation in supercritical electric fields limits the net charge of any static, spherical object, such as superheavy nuclei, strangelets, and Q balls, or compact stars like neutron stars, quark stars, and black holes. For radii between 4x10{sup 2} and 10{sup 4} fm the upper bound on the net charge is given by the universal relation Z=0.71R{sub fm}, and for larger radii (measured in femtometers or kilometers) Z=7x10{sup -5}R{sub fm}{sup 2}=7x10{sup 31}R{sub km}{sup 2}. For objects with nuclear density the relation corresponds to Z{approx_equal}0.7A{sup 1/3} (10{sup 8}10{sup 12}), where A is the baryonmore » number. For some systems this universal upper bound improves existing charge limits in the literature.« less

Automation of experiments at Dubna Gas-Filled Recoil Separator

NASA Astrophysics Data System (ADS)

Tsyganov, Yu. S.

2016-01-01

Approaches to solving the problems of automation of basic processes in long-term experiments in heavy ion beams of the Dubna Gas-Filled Recoil Separator (DGFRS) facility are considered. Approaches in the field of spectrometry, both of rare α decays of superheavy nuclei and those for constructing monitoring systems to provide accident-free experiment running with highly radioactive targets and recording basic parameters of experiment, are described. The specific features of Double Side Silicon Strip Detectors (DSSSDs) are considered, special attention is paid to the role of boundary effects of neighboring p-n transitions in the "active correlations" method. An example of an off-beam experiment attempting to observe Zeno effect is briefly considered. Basic examples for nuclear reactions of complete fusion at 48Ca ion beams of U-400 cyclotron (LNR, JINR) are given. A scenario of development of the "active correlations" method for the case of very high intensity beams of heavy ions at promising accelerators of LNR, JINR, is presented.

Phenomenology with F-theory S U (5 )

NASA Astrophysics Data System (ADS)

Leontaris, George K.; Shafi, Qaisar

2017-09-01

We explore the low-energy phenomenology of an F-theory-based S U (5 ) model which, in addition to the known quarks and leptons, contains Standard Model (SM) singlets and vectorlike color triplets and S U (2 ) doublets. Depending on their masses and couplings, some of these new particles may be observed at the LHC and future colliders. We discuss the restrictions by Cabibbo-Kobayashi-Maskawa matrix constraints on their mixing with the ordinary down quarks of the three chiral families. The model is consistent with gauge coupling unification at the usual supersymmetric GUT scale; dimension-five proton decay is adequately suppressed, while dimension-six decay mediated by the superheavy gauge bosons is enhanced by a factor of 5-7. The third generation charged fermion Yukawa couplings yield the corresponding low-energy masses in reasonable agreement with observations. The hierarchical nature of the masses of lighter generations is accounted for via nonrenormalizable interactions, with the perturbative vacuum expectation values (VEVs) of the SM singlet fields playing an essential role.

The current status of the MASHA setup

NASA Astrophysics Data System (ADS)

Vedeneev, V. Yu.; Rodin, A. M.; Krupa, L.; Belozerov, A. V.; Chernysheva, E. V.; Dmitriev, S. N.; Gulyaev, A. V.; Gulyaeva, A. V.; Kamas, D.; Kliman, J.; Komarov, A. B.; Motycak, S.; Novoselov, A. S.; Salamatin, V. S.; Stepantsov, S. V.; Podshibyakin, A. V.; Yukhimchuk, S. A.; Granja, C.; Pospisil, S.

2017-11-01

The MASHA setup designed as the mass-separator with the resolving power of about 1700, which allows mass identification of superheavy nuclides is described. The setup uses solid ISOL (Isotope Separation On-Line) method. In the present article the upgrade of some parts of MASHA are described: target box (rotating target + hot catcher), ion source based on electron cyclotron resonance, data acquisition, beam diagnostics and control systems. The upgrade is undertaken in order to increase the total separation efficiency, reduce the separation time, of the installation and working stability and make possible continuous measurements at high beam currents. Ion source efficiency was measured in autonomous regime with using calibrated gas leaks of Kr and Xe injected directly to ion source. Some results of the first experiments for production of radon isotopes using the multi-nucleon transfer reaction 48Ca+242Pu are described in the present article. The using of TIMEPIX detector with MASHA setup for neutron-rich Rn isotopes identification is also described.

Guided wave propagation and spectral element method for debonding damage assessment in RC structures

NASA Astrophysics Data System (ADS)

Wang, Ying; Zhu, Xinqun; Hao, Hong; Ou, Jinping

2009-07-01

A concrete-steel interface spectral element is developed to study the guided wave propagation along the steel rebar in the concrete. Scalar damage parameters characterizing changes in the interface (debonding damage) are incorporated into the formulation of the spectral finite element that is used for damage detection of reinforced concrete structures. Experimental tests are carried out on a reinforced concrete beam with embedded piezoelectric elements to verify the performance of the proposed model and algorithm. Parametric studies are performed to evaluate the effect of different damage scenarios on wave propagation in the reinforced concrete structures. Numerical simulations and experimental results show that the method is effective to model wave propagation along the steel rebar in concrete and promising to detect damage in the concrete-steel interface.

Synthetic Modifications In the Frequency Domain for Finite Element Model Update and Damage Detection

DTIC Science & Technology

2017-09-01

Sensitivity-based finite element model updating and structural damage detection has been limited by the number of modes available in a vibration test and...increase the number of modes and corresponding sensitivity data by artificially constraining the structure under test, producing a large number of... structural modifications to the measured data, including both springs-to-ground and mass modifications. This is accomplished with frequency domain

Design and evaluation of a failure detection and isolation algorithm for restructurable control systems

NASA Technical Reports Server (NTRS)

Weiss, Jerold L.; Hsu, John Y.

1986-01-01

The use of a decentralized approach to failure detection and isolation for use in restructurable control systems is examined. This work has produced: (1) A method for evaluating fundamental limits to FDI performance; (2) Application using flight recorded data; (3) A working control element FDI system with maximal sensitivity to critical control element failures; (4) Extensive testing on realistic simulations; and (5) A detailed design methodology involving parameter optimization (with respect to model uncertainties) and sensitivity analyses. This project has concentrated on detection and isolation of generic control element failures since these failures frequently lead to emergency conditions and since knowledge of remaining control authority is essential for control system redesign. The failures are generic in the sense that no temporal failure signature information was assumed. Thus, various forms of functional failures are treated in a unified fashion. Such a treatment results in a robust FDI system (i.e., one that covers all failure modes) but sacrifices some performance when detailed failure signature information is known, useful, and employed properly. It was assumed throughout that all sensors are validated (i.e., contain only in-spec errors) and that only the first failure of a single control element needs to be detected and isolated. The FDI system which has been developed will handle a class of multiple failures.

Region-growing approach to detect microcalcifications in digital mammograms

NASA Astrophysics Data System (ADS)

Shin, Jin-Wook; Chae, Soo-Ik; Sook, Yoon M.; Park, Dong-Sun

2001-09-01

Detecting early symptoms of breast cancer is very important to enhance the possibility of cure. There have been active researches to develop computer-aided diagnosis(CAD) systems detecting early symptoms of breast cancer in digital mammograms. An expert or a CAD system can recognize the early symptoms based on microcalcifications appeared in digital mammographic images. Microcalcifications have higher gray value than surrounding regions, so these can be detected by expanding a region from a local maximum. However the resultant image contains unnecessary elements such as noise, holes and valleys. Mathematical morphology is a good solution to delete regions that are affected by the unnecessary elements. In this paper, we present a method that effectively detects microcalcifications in digital mammograms using a combination of local maximum operation and the region-growing operation.

Multivariate analysis of elemental chemistry as a robust biosignature

NASA Astrophysics Data System (ADS)

Storrie-Lombardi, M.; Nealson, K.

2003-04-01

The robotic detection of life in extraterrestrial settings (i.e., Mars, Europa, etc.) would be greatly simplified if analysis could be accomplished in the absence of direct mechanical manipulation of a sample. It would also be preferable to employ a fundamental physico-chemical phenomenon as a biosignature and depend less on the particular manifestations of life on Earth (i.e. to employ non-earthcentric methods). One such approach, which we put forward here, is that of elemental composition, a reflection of the use of specific chemical elements for the construction of living systems. Using appropriate analyses (over the proper spatial scales), it should be possible to see deviations from the geological background (mineral and geochemical composition of the crust), and identify anomalies that would indicate sufficient deviation from the norm as to indicate a possible living system. To this end, over the past four decades elemental distributions have been determined for the sun, the interstellar medium, seawater, the crust of the Earth, carbonaceous chondrite meteorites, bacteria, plants, animals, and human beings. Such data can be relatively easily obtained for samples of a variety of types using a technique known as laser-induced breakdown spectroscopy (LIBS), which employs a high energy laser to ablate a portion of a sample, and then determine elemental composition using remote optical spectroscopy. However, the elements commonly associated with living systems (H, C, O, and N), while useful for detecting extant life, are relatively volatile and are not easily constrained across geological time scales. This minimizes their utility as fossil markers of ancient life. We have investigated the possibility of distinguishing the distributions of less volatile elements in a variety of biological materials from the distributions found in carbonaceous chondrites and the Earth’s crust using principal component analysis (PCA), a classical multivariate analysis technique capable of optimizing classification using spectral or multiple variable inputs. We present initial results indicating that 21 elements are of particular utility and can produce clear classification with no errors when used in minimum sets of four (4), e.g. [V-23, Ti-22, Cr-24, I-53] or [Al-13, Si-14, P-15, Fe-26]. The detection limits and ease of approach suggest that these methods should be valuable for detection of biological residual signatures against specific Mars mineral backgrounds. Clearly, measurements must be made at the proper spatial scales in order to see these anomalies, and data must be analyzed with no pre-predjudice of what the elemental composition of life should be - both of these potential problems are easily dealt with. Of particular interest is the observation that many non-volatile elements can be effectively used for life detection, suggesting that fossilized (e.g., dead or even extinct) samples may retain these inorganic signatures of past life.

Sensors for detecting analytes in fluids

NASA Technical Reports Server (NTRS)

Lewis, Nathan S. (Inventor); Severin, Erik (Inventor)

1998-01-01

Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g., electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.

Multivariate classification of edible salts: Simultaneous Laser-Induced Breakdown Spectroscopy and Laser-Ablation Inductively Coupled Plasma Mass Spectrometry Analysis

NASA Astrophysics Data System (ADS)

Lee, Yonghoon; Nam, Sang-Ho; Ham, Kyung-Sik; Gonzalez, Jhanis; Oropeza, Dayana; Quarles, Derrick; Yoo, Jonghyun; Russo, Richard E.

2016-04-01

Laser-Induced Breakdown Spectroscopy (LIBS) and Laser-Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), both based on laser ablation sampling, can be employed simultaneously to obtain different chemical fingerprints from a sample. We demonstrated that this analysis approach can provide complementary information for improved classification of edible salts. LIBS could detect several of the minor metallic elements along with Na and Cl, while LA-ICP-MS spectra were used to measure non-metallic and trace heavy metal elements. Principal component analysis using LIBS and LA-ICP-MS spectra showed that their major spectral variations classified the sample salts in different ways. Three classification models were developed by using partial least squares-discriminant analysis based on the LIBS, LA-ICP-MS, and their fused data. From the cross-validation performances and confusion matrices of these models, the minor metallic elements (Mg, Ca, and K) detected by LIBS and the non-metallic (I) and trace heavy metal (Ba, W, and Pb) elements detected by LA-ICP-MS provided complementary chemical information to distinguish particular salt samples.

Sensors for detecting analytes in fluids

NASA Technical Reports Server (NTRS)

Severin, Erik (Inventor); Lewis, Nathan S. (Inventor)

2001-01-01

Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g., electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.

Sensors for detecting analytes in fluids

NASA Technical Reports Server (NTRS)

Lewis, Nathan S. (Inventor); Severin, Erik (Inventor)

1999-01-01

Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g., electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.

Sensor arrays for detecting analytes in fluids

NASA Technical Reports Server (NTRS)

Lewis, Nathan S. (Inventor); Freund, Michael S. (Inventor)

1996-01-01

Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g. electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.

Systems and methods for detecting x-rays

DOEpatents

Bross, Alan D.; Mellott, Kerry L.; Pla-Dalmau, Anna

2006-05-02

Systems and methods for detecting x-rays are disclosed herein. One or more x-ray-sensitive scintillators can be configured from a plurality of heavy element nano-sized particles and a plastic material, such as polystyrene. As will be explained in greater detail herein, the heavy element nano-sized particles (e.g., PbWO₄) can be compounded into the plastic material with at least one dopant that permits the plastic material to scintillate. X-rays interact with the heavy element nano-sized particles to produce electrons that can deposit energy in the x-ray sensitive scintillator, which in turn can produce light.

Solid State Carbon Monoxide Sensor

NASA Technical Reports Server (NTRS)

Upchurch, Billy T. (Inventor); Wood, George M. (Inventor); Schryer, David R. (Inventor); Leighty, Bradley D. (Inventor); Oglesby, Donald M. (Inventor); Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); DAmbrosia, Christine M. (Inventor)

1999-01-01

A means for detecting carbon monoxide which utilizes an un-heated catalytic material to oxidize carbon monoxide at ambient temperatures. Because this reaction is exothermic, a thermistor in contact with the catalytic material is used as a sensing element to detect the heat evolved as carbon monoxide is oxidized to carbon dioxide at the catalyst surface, without any heaters or external heating elements for the ambient air or catalytic element material. Upon comparison to a reference thermistor, relative increases in the temperature of the sensing thermistor correspond positively with an increased concentration of carbon monoxide in the ambient medium and are thus used as an indicator of the presence of carbon monoxide.

The Unexplored Domains of the s-Process

NASA Astrophysics Data System (ADS)

Roederer, Ian

2016-10-01

Understanding the origin of the elements is one of the major challenges of modern astrophysics. Abundance measurements in late-type stars are used to test nucleosynthesis models, and the models in turn reveal the nature of the progenitor star(s) that produced the metals observed today. Elements listed along the bottom two-thirds of the periodic table are produced by neutron-capture reactions, such as the r-process or s-process. Previous studies have expanded the chemical inventory of individual r-process-enhanced stars to >50 elements per star. Here, we propose to do the same for an s-process-enhanced star.We propose new high-resolution STIS/E230H observations (2024-2301 Angstroms) of the star HD 196944, the UV-brightest s-process-enhanced metal-poor star in the sky. Lines of Se I, Mo II, Cd I, Cd II, Sn I, Sb I, Te I, Yb II, W II, Re II, Os II, Pt I, Pb II, and Bi I should be detectable in these observations because of the high spectral resolution and S/N. No star offers the opportunity to simultaneously detect all of these elements, and several of them could be detected for the first time. We will combine these NUV detections with optical detections to test many specific predictions of the s-process nucleosynthesis models in a way that has not been possible until now. This is particularly timely, for example, because s-process models have recently been shown to be uncertain at the termination point around Pb-Bi.

DETECTION OF COATING FAILURES IN A NEUTRONIC REACTOR

DOEpatents

Snell, A.H.; Allison, S.K.

1958-02-11

This patent relates to water-cooled reactor systems and discloses a means to detect leaks in the jackets of jacketed fuel elements comprising a neutron detector located in the cooling water discharge pipe,the pipe being provided with an enlarged portion for housing the detector so that the latter is completely surrounded by the water in its passage through the pipe, said enlarged portion and detector being shielded from the reactor for the purpose of detecting only those delayed neutrons emitted in the cooling water and due to the latter picking up fission fragments from the defective fuel elements.

Application of wavelet based MFDFA on Mueller matrix images for cervical pre-cancer detection

NASA Astrophysics Data System (ADS)

Zaffar, Mohammad; Pradhan, Asima

2018-02-01

A systematic study has been conducted on application of wavelet based multifractal de-trended fluctuation analysis (MFDFA) on Mueller matrix (MM) images of cervical tissue sections for early cancer detection. Changes in multiple scattering and orientation of fibers are observed by utilizing a discrete wavelet transform (Daubechies) which identifies fluctuations over polynomial trends. Fluctuation profiles, after 9th level decomposition, for all elements of MM qualitatively establish a demarcation of different grades of cancer from normal tissue. Moreover, applying MFDFA on MM images, Hurst exponent profiles for images of MM qualitatively are seen to display differences. In addition, the values of Hurst exponent increase for the diagonal elements of MM with increasing grades of the cervical cancer, while the value for the elements which correspond to linear polarizance decrease. However, for circular polarizance the value increases with increasing grades. These fluctuation profiles reveal the trend of local variation of refractive -indices and along with Hurst exponent profile, may serve as a useful biological metric in the early detection of cervical cancer. The quantitative measurements of Hurst exponent for diagonal and first column (polarizance governing elements) elements which reflect changes in multiple scattering and structural anisotropy in stroma, may be sensitive indicators of pre-cancer.

Sub-micron Hard X-ray Fluorescence Imaging of Synthetic Elements

PubMed Central

Jensen, Mark P.; Aryal, Baikuntha P.; Gorman-Lewis, Drew; Paunesku, Tatjana; Lai, Barry; Vogt, Stefan; Woloschak, Gayle E.

2013-01-01

Synchrotron-based X-ray fluorescence microscopy (SXFM) using hard X-rays focused into sub-micron spots is a powerful technique for elemental quantification and mapping, as well as microspectroscopic measurement such as μ-XANES (X-ray absorption near edge structure). We have used SXFM to image and simultaneously quantify the transuranic element plutonium at the L3 or L2 edge as well as lighter biologically essential elements in individual rat pheochromocytoma (PC12) cells after exposure to the long-lived plutonium isotope 242Pu. Elemental maps reveal that plutonium localizes principally in the cytoplasm of the cells and avoids the cell nucleus, which is marked by the highest concentrations of phosphorus and zinc, under the conditions of our experiments. The minimum detection limit under typical acquisition conditions for an average 202 μm2 cell is 1.4 fg Pu/cell or 2.9 × 10−20 moles Pu/μm2, which is similar to the detection limit of K-edge SXFM of transition metals at 10 keV. Copper electron microscopy grids were used to avoid interference from gold X-ray emissions, but traces of strontium present in naturally occurring calcium can still interfere with plutonium detection using its Lα X-ray emission. PMID:22444530

Evaluation of Incident Detection Methodologies

DOT National Transportation Integrated Search

1999-10-01

Original Report Date: October 1998. The detection of freeway incidents is an essential element of an area's traffic management system. Incidents need to be detected and handled as promptly as possible to minimize delay to the public. Various algorith...

ENVIRONMENTAL APPLICATION OF GAS CHROMATOGRAPHY/ATOMIC EMISSION DETECTION

EPA Science Inventory

A gas chromatography/atomic emission detector (GC/AED) system has been evaluated for its applicability to environmental analysis. Detection limits, elemental response factors, and regression analysis data were determined for 58 semivolatile environmental contaminants. Detection l...

Classifying threats with a 14-MeV neutron interrogation system.

PubMed

Strellis, Dan; Gozani, Tsahi

2005-01-01

SeaPODDS (Sea Portable Drug Detection System) is a non-intrusive tool for detecting concealed threats in hidden compartments of maritime vessels. This system consists of an electronic neutron generator, a gamma-ray detector, a data acquisition computer, and a laptop computer user-interface. Although initially developed to detect narcotics, recent algorithm developments have shown that the system is capable of correctly classifying a threat into one of four distinct categories: narcotic, explosive, chemical weapon, or radiological dispersion device (RDD). Detection of narcotics, explosives, and chemical weapons is based on gamma-ray signatures unique to the chemical elements. Elements are identified by their characteristic prompt gamma-rays induced by fast and thermal neutrons. Detection of RDD is accomplished by detecting gamma-rays emitted by common radioisotopes and nuclear reactor fission products. The algorithm phenomenology for classifying threats into the proper categories is presented here.

Elements including metals in the atomizer and aerosol of disposable electronic cigarettes and electronic hookahs.

PubMed

Williams, Monique; Bozhilov, Krassimir; Ghai, Sanjay; Talbot, Prue

2017-01-01

Our purpose was to quantify 36 inorganic chemical elements in aerosols from disposable electronic cigarettes (ECs) and electronic hookahs (EHs), examine the effect of puffing topography on elements in aerosols, and identify the source of the elements. Thirty-six inorganic chemical elements and their concentrations in EC/EH aerosols were determined using inductively coupled plasma optical emission spectroscopy, and their source was identified by analyzing disassembled atomizers using scanning electron microscopy and energy dispersive X-ray spectroscopy. Of 36 elements screened, 35 were detected in EC/EH aerosols, while only 15 were detected in conventional tobacco smoke. Some elements/metals were present in significantly higher concentrations in EC/EH aerosol than in cigarette smoke. Concentrations of particular elements/metals within EC/EH brands were sometimes variable. Aerosols generated at low and high air-flow rates produced the same pattern of elements, although the total element concentration decreased at the higher air flow rate. The relative amount of elements in the first and last 60 puffs was generally different. Silicon was the dominant element in aerosols from all EC/EH brands and in cigarette smoke. The elements appeared to come from the filament (nickel, chromium), thick wire (copper coated with silver), brass clamp (copper, zinc), solder joints (tin, lead), and wick and sheath (silicon, oxygen, calcium, magnesium, aluminum). Lead was identified in the solder and aerosol of two brands of EHs (up to 0.165 μg/10 puffs). These data show that EC/EH aerosols contain a mixture of elements, including heavy metals, with concentrations often significantly higher than in conventional cigarette smoke. While the health effects of inhaling mixtures of heated metals is currently not known, these data will be valuable in future risk assessments involving EC/EH elements/metals.

Laser-induced breakdown spectroscopy for specimen analysis

DOEpatents

Kumar, Akshaya; Yu-Yueh, Fang; Burgess, Shane C.; Singh, Jagdish P.

2006-08-15

The present invention is directed to an apparatus, a system and a method for detecting the presence or absence of trace elements in a biological sample using Laser-Induced Breakdown Spectroscopy. The trace elements are used to develop a signature profile which is analyzed directly or compared with the known profile of a standard. In one aspect of the invention, the apparatus, system and method are used to detect malignant cancer cells in vivo.

A preliminary evaluation of the generalized likelihood ratio for detecting and identifying control element failures in a transport aircraft

NASA Technical Reports Server (NTRS)

Bundick, W. T.

1985-01-01

The application of the Generalized Likelihood Ratio technique to the detection and identification of aircraft control element failures has been evaluated in a linear digital simulation of the longitudinal dynamics of a B-737 aircraft. Simulation results show that the technique has potential but that the effects of wind turbulence and Kalman filter model errors are problems which must be overcome.

Elemental speciation for chromium in chromium picolinate products

NASA Astrophysics Data System (ADS)

Ding, Hong; Olson, Lisa K.; Caruso, Joseph A.

1996-12-01

Chromium picolinate products have been examined for different forms of chromium, using chromatographic separation and inductively coupled plasma mass spectrometric detection. The brands we evaluated contained no detectable amount of elemental chromium(VI), the toxic form. Since chromium picolinate might have other chromium forms as impurities, different products may contain different forms of chromium species. Compared with ion-exchange, reversed-phase chromatography showed excellent chromium recovery based on the amount stated on the product label.

Hybrid electro-optical nanosystem for neurons investigation

NASA Astrophysics Data System (ADS)

Miu, Mihaela; Kleps, Irina; Craciunoiu, Florea; Simion, Monica; Bragaru, Adina; Ignat, Teodora

2010-11-01

The scope of this paper is development of a new laboratory-on-a-chip (LOC) device for biomedical studies consisting of a microfluidic system coupled to microelectronic/optical transducers with nanometric features, commonly called biosensors. The proposed device is a hybrid system with sensing element on silicon (Si) chip and microfluidic system on polydimethylsiloxane (PDMS) substrates, taking into accounts their particular advantages. Different types of nanoelectrode arrays, positioned in the reactor, have been investigated as sensitive elements for electrical detection and the recording of neuron extracellular electric activity has been monitorized in parallel with whole-cell patch-clamp membrane current. Moreover, using an additional porosification process the sensing element became efficient for optical detection also. The preliminary test results demonstrate the functionality of the proposed design and also the fabrication technology, the devices bringing advantages in terms enhancement of sensitivity in both optoelectronic detection schemes.

Complementary use of ion beam elastic backscattering and recoil detection analysis for the precise determination of the composition of thin films made of light elements

NASA Astrophysics Data System (ADS)

Climent-Font, A.; Cervera, M.; Hernández, M. J.; Muñoz-Martín, A.; Piqueras, J.

2008-04-01

Rutherford backscattering spectrometry (RBS) is a well known powerful technique to obtain depth profiles of the constituent elements in a thin film deposited on a substrate made of lighter elements. In its standard use the probing beam is typically 2 MeV He. Its capabilities to obtain precise composition profiles are severely diminished when the overlaying film is made of elements lighter than the substrate. In this situation the analysis of the energy of the recoiled element from the sample in the elastic scattering event, the ERDA technique may be advantageous. For the detection of light elements it is also possible to use beams at specific energies producing elastic resonances with these light elements to be analyzed, with a much higher scattering cross sections than the Rutherford values. This technique may be called non-RBS. In this work we report on the complementary use of ERDA with a 30 MeV Cl beam and non-RBS with 1756 keV H ions to characterize thin films made of boron, carbon and nitrogen (BCN) deposited on Si substrates.

Photoinduced Regeneration of an Aptamer-Based Electrochemical Sensor for Sensitively Detecting Adenosine Triphosphate.

PubMed

Zhang, Xiaoyu; Song, Chunxia; Yang, Ke; Hong, Wenwen; Lu, Ying; Yu, Ping; Mao, Lanqun

2018-04-17

Electrochemical aptasensors generally include three elements, that is, recognition element, signal-transformation element, and regeneration element. In this study, a new adenosine triphosphate (ATP) aptasensor is developed by combining three elements into one DNA oligonucleotide chain. In the DNA oligonucleotide chain, DNA aptamer is used as the recognition element, ferrocene group attached at the 3'-end of the aptamer is used as the signal-transformation element, and azobenzene moiety embedded into the DNA chain is used as the regeneration element. In addition to the similar analytical properties with the traditional ones, the aptasensor developed here is easily regenerated with UV-light irradiation. The current response recorded on the aptasensor increases with increasing the concentration of ATP in the incubation solution and is linear with the logarithm of ATP concentration in the range from 1 nM to 100 μM. The limit of detection is 0.5 nM (S/N = 3). The basal level of ATP in the rat brain cortex microdialysate is determined to be 21.33 ± 4.1 nM ( n = 3). After being challenged with ATP, the aptasensor could be readily regenerated by UV-light irradiation for more than seven cycles. The regeneration of the aptasensor is proposed to be regulated by conversing azobenzene from its trans to cis form under UV irradiation.

Trace elements and organic compounds in streambed sediment and aquatic biota from the Sacramento River Basin, California, October and November 1995

USGS Publications Warehouse

MacCoy, Dorene E.; Domagalski, Joseph L.

1999-01-01

Elevated levels of trace elements and hydrophobic organic compounds were detected in streambed sediments and aquatic biota [Asiatic clam (Corbicula fluminea) or bottom-feeding fish] of the Sacramento River Basin, California, during October and November 1995. Trace elements detected included cadmium, copper, mercury, lead, and zinc. Elevated levels of cadmium, copper, and zinc in the upper Sacramento River are attributed to a mining land use, and elevated levels of zinc and lead in an urban stream, and possibly in the lower Sacramento River, are attributed to urban runoff processes. Elevated levels of mercury in streambed sediment are attributed to either past mercury mining or to the use of mercury in past gold mining operations. Mercury mining was an important land use within the Coast Ranges in the past and gold mining was an important land use of the Sierra Nevada in the past. Mercury was the only trace element found in elevated levels in the tissue of aquatic biota, and those levels also could be attributed to either mining or urban runoff. Hydrophobic organic compounds also were detected in streambed sediments and aquatic biota. The most frequently detected compounds were DDT and its breakdown products, dieldrin, oxychlordane, and toxaphene. Differences were found in the types of compounds detected at agricultural sites and the urban site. Although both types of sites had measurable concentrations of DDT or its breakdown products, the urban site also had measurable concentrations of pesticides used for household pest control. Few semivolatile compounds were detected in the streambed sediments of any site. The semivolatile compound p-cresol, a coal-tar derivative associated with road maintenance, was found in the highest concentration.

Interagency partnering for weed prevention--progress on development of a National Early Detection and Rapid Response System for Invasive Plants in the United States

USGS Publications Warehouse

Westbrooks, R.; Westbrooks, R.

2011-01-01

Over the past 50 years, experience has shown that interagency groups provide an effective forum for addressing various invasive species issues and challenges on multiple land units. However, more importantly, they can also provide a coordinated framework for early detection, reporting, identification and vouchering, rapid assessment, and rapid response to new and emerging invasive plants in the United States. Interagency collaboration maximizes the use of available expertise, resources, and authority for promoting early detection and rapid response (EDRR) as the preferred management option for addressing new and emerging invasive plants. Currently, an interagency effort is underway to develop a National EDRR System for Invasive Plants in the United States. The proposed system will include structural and informational elements. Structural elements of the system include a network of interagency partner groups to facilitate early detection and rapid response to new invasive plants, including the Federal Interagency Committee for the Management of Noxious and Exotic Weeds (FICMNEW), State Invasive Species Councils, State Early Detection and Rapid Response Coordinating Committees, State Volunteer Detection and Reporting Networks, Invasive Plant Task Forces, and Cooperative Weed Management Areas. Informational elements and products being developed include Regional Invasive Plant Atlases, and EDRR Guidelines for EDRR Volunteer Network Training, Rapid Assessment and Rapid Response, and Criteria for Selection of EDRR Species. System science and technical support elements which are provided by cooperating state and federal scientists, include EDRR guidelines, training curriculum for EDRR volunteers and agency field personnel, plant identification and vouchering, rapid assessments, as well as predictive modeling and ecological range studies for invasive plant species.

Monte Carlo Simulation of Soil Moisture Effects on Anti-Tank Landmines Detection by Neutron Backscattering Technique

NASA Astrophysics Data System (ADS)

Mowlawi, Ali Asghar; Yazdani, Majed

The detection of landmines using available technologies is a time consuming, expensive, and extremely dangerous job, so that there is a need for technological breakthroughs in this field. One of the safest and most effective technologies to landmine and explosive detection is the neutron backscattering technique. The slowing-down of fast neutrons to the thermal energy is a direct measure of the concentration of hydrogen, one of the main elements present in explosive materials. The elastic scattering of fast neutrons is affected by the strong resonances in the cross-section of the three other elements of explosives: nitrogen, oxygen, and carbon. In this work, Monte Carlo estimations of the soil moisture effects on landmine detection are presented.

Modular optical detector system

DOEpatents

Horn, Brent A [Livermore, CA; Renzi, Ronald F [Tracy, CA

2006-02-14

A modular optical detector system. The detector system is designed to detect the presence of molecules or molecular species by inducing fluorescence with exciting radiation and detecting the emitted fluorescence. Because the system is capable of accurately detecting and measuring picomolar concentrations it is ideally suited for use with microchemical analysis systems generally and capillary chromatographic systems in particular. By employing a modular design, the detector system provides both the ability to replace various elements of the detector system without requiring extensive realignment or recalibration of the components as well as minimal user interaction with the system. In addition, the modular concept provides for the use and addition of a wide variety of components, including optical elements (lenses and filters), light sources, and detection means, to fit particular needs.

SINE sequences detect DNA fingerprints in salmonid fishes.

PubMed

Spruell, P; Thorgaard, G H

1996-04-01

DNA probes homologous to two previously described salmonid short interspersed nuclear elements (SINEs) detected DNA fingerprint patterns in 14 species of salmonid fishes. The probes showed more homology to some species than to others and little homology to three nonsalmonid fishes. The DNA fingerprint patterns derived from the SINE probes are individual-specific and inherited in a Mendelian manner. Probes derived from different regions of the same SINE detect only partially overlapping banding patterns, reflecting a more complex SINE structure than has been previously reported. Like the human Alu sequence, the SINEs found in salmonids could provide useful genetic markers and primer sites for PCR-based techniques. These elements may be more desirable for some applications than traditional DNA fingerprinting probes that detect tandemly repeated arrays.

77 FR 51807 - Agency Forms Undergoing Paperwork Reduction Act Review

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-27

... Minimum Data Elements (MDEs) for the National Breast and Cervical Cancer Early Detection Program (NBCCEDP... screening and early detection tests for breast and cervical cancer. Mammography is extremely valuable as an early detection tool because it can detect breast cancer well before the woman can feel the lump, when...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di, Zichao; Chen, Si; Hong, Young Pyo

X-ray fluorescence tomography is based on the detection of fluorescence x-ray photons produced following x-ray absorption while a specimen is rotated; it provides information on the 3D distribution of selected elements within a sample. One limitation in the quality of sample recovery is the separation of elemental signals due to the finite energy resolution of the detector. Another limitation is the effect of self-absorption, which can lead to inaccurate results with dense samples. To recover a higher quality elemental map, we combine x-ray fluorescence detection with a second data modality: conventional x-ray transmission tomography using absorption. By using these combinedmore » signals in a nonlinear optimization-based approach, we demonstrate the benefit of our algorithm on real experimental data and obtain an improved quantitative reconstruction of the spatial distribution of dominant elements in the sample. Furthermore, compared with single-modality inversion based on x-ray fluorescence alone, this joint inversion approach reduces ill-posedness and should result in improved elemental quantification and better correction of self-absorption.« less

Joint reconstruction of x-ray fluorescence and transmission tomography

PubMed Central

Di, Zichao Wendy; Chen, Si; Hong, Young Pyo; Jacobsen, Chris; Leyffer, Sven; Wild, Stefan M.

2017-01-01

X-ray fluorescence tomography is based on the detection of fluorescence x-ray photons produced following x-ray absorption while a specimen is rotated; it provides information on the 3D distribution of selected elements within a sample. One limitation in the quality of sample recovery is the separation of elemental signals due to the finite energy resolution of the detector. Another limitation is the effect of self-absorption, which can lead to inaccurate results with dense samples. To recover a higher quality elemental map, we combine x-ray fluorescence detection with a second data modality: conventional x-ray transmission tomography using absorption. By using these combined signals in a nonlinear optimization-based approach, we demonstrate the benefit of our algorithm on real experimental data and obtain an improved quantitative reconstruction of the spatial distribution of dominant elements in the sample. Compared with single-modality inversion based on x-ray fluorescence alone, this joint inversion approach reduces ill-posedness and should result in improved elemental quantification and better correction of self-absorption. PMID:28788848

Detection of Fingerprints Based on Elemental Composition Using Micro-X-Ray Fluorescence.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Worley, C. G.; Wiltshire, S.; Miller, T. C.

A method was developed to detect fingerprints using a technique known as micro-X-ray fluorescence. The traditional method of detecting fingerprints involves treating the sample with certain powders, liquids, or vapors to add color to the fingerprint so that it can be easily seen and photographed for forensic purposes. This is known as contrast enhancement, and a multitude of chemical processing methods have been developed in the past century to render fingerprints visible. However, fingerprints present on certain substances such as fibrous papers and textiles, wood, leather, plastic, adhesives, and human skin can sometimes be difficult to detect by contrast enhancement.more » Children's fingerprints are also difficult to detect due to the absence of sebum on their skin, and detection of prints left on certain colored backgrounds can sometimes be problematic. Micro-X-ray fluorescence (MXRF) was studied here as a method to detect fingerprints based on chemical elements present in fingerprint residue. For example, salts such as sodium chloride and potassium chloride excreted in sweat are sometimes present in detectable quantities in fingerprints. We demonstrated that MXRF can be used to detect this sodium, potassium, and chlorine from such salts. Furthermore, using MXRF, each of these elements (and many other elements if present) can be detected as a function of location on a surface, so we were able to 'see' a fingerprint because these salts are deposited mainly along the patterns present in a fingerprint (traditionally called friction ridges in forensic science). MXRF is not a panacea for detecting all fingerprints; some prints will not contain enough detectable material to be 'seen'; however, determining an effective means of coloring a fingerprint with traditional contrast enhancement methods can sometimes be an arduous process with limited success. Thus, MXRF offers a possible alternative for detecting fingerprints, and it does not require any additional chemical treatment steps which can be time consuming and permanently alter the sample. Additionally, MXRF is noninvasive, so a fingerprint analyzed by this method is left pristine for examination by other methods (eg. DNA extraction). To the best of the author's knowledge, no studies have been published to date concerning the detection of fingerprints by micro-X-ray fluorescence. Some studies have been published in which other spectroscopic methods were employed to examine the chemical composition of fingerprints (eg. IR, SEM/EDX, and Auger), but very few papers discuss the actual detection and imaging of a complete fingerprint by any spectroscopic method. Thus, this work is unique.« less

Occurrence and distribution of organochlorine pesticides, polychlorinated biphenyls, and trace elements in fish tissue in the lower Tennessee River basin, 1980-98

USGS Publications Warehouse

Knight, R.R.; Powell, J.R.

2001-01-01

The U.S. Geological Survey, as part of the National Water-Quality Assessment Program, evaluated the occurrence and distribution of organochlorine pesticides, polychlorinated biphenyls, and trace elements in fish tissue in samples collected in the lower Tennessee River Basin study unit. Fish tissue analysis provides a time-averaged measurement of contaminants as well as a direct measurement of the contaminants that bioaccumulate in fish tissue. Bioaccumulation of contaminants in fish tissue may result in concentrations that can affect human, wildlife, or aquatic health. Data for two types of tissue analyses were evaluated to assess the occurrence and distribution of contaminants: whole fish for organochlorine pesticides and polychlorinated biphenyls and fish fillets for organochlorine pesticides, polychlorinated biphenyls, and trace elements. The fish tissue data analyzed for this study cover an 18-year span including data collected in 1998 by the U.S. Geological Survey as part of the National Water-Quality Assessment Program; data collected from 1980 through 1997 by the Tennessee Valley Authority; and data collected from 1992 through 1997 by the Tennessee Department of Environment and Conservation. Concentration data for constituents that are on the U.S. Environmental Protection Agency Priority Pollutant List were summarized and compared against existing action levels or guidelines.From the list of organochlorine pesticide compounds analyzed, p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), a breakdown product of dichlorodiphenyltrichloroethane (DDT), was the most commonly detected compound with detections at 83 percent of the sites sampled. Eleven p,p'-DDE samples exceeded action levels or guidelines with concentrations ranging from 0.20 to 12.8 milligrams per kilogram. Five other organochlorine compounds, p,p'-dichlorodiphenyldichloroethane (p,p'-DDD), dieldrin, endrin, chlordane, and polychlorinated biphenyls, also exceeded action levels and guidelines, but the detection frequencies at sampling sites generally were less than 70 percent. Mercury, the only trace element to exceed a guideline, was detected at 51 of 102 sites sampled for trace elements. Selenium was detected in fish fillet samples from 70 of 102 sites sampled, which was more sites than for any other trace element; however, selenium did not exceed the 50 micrograms per gram U.S. Environmental Protection Agency screening criteria. Arsenic and cadmium also were detected at 44 and 54 percent of the sampling sites, respectively.

Nanoparticle size detection limits by single particle ICP-MS for 40 elements.

PubMed

Lee, Sungyun; Bi, Xiangyu; Reed, Robert B; Ranville, James F; Herckes, Pierre; Westerhoff, Paul

2014-09-02

The quantification and characterization of natural, engineered, and incidental nano- to micro-size particles are beneficial to assessing a nanomaterial's performance in manufacturing, their fate and transport in the environment, and their potential risk to human health. Single particle inductively coupled plasma mass spectrometry (spICP-MS) can sensitively quantify the amount and size distribution of metallic nanoparticles suspended in aqueous matrices. To accurately obtain the nanoparticle size distribution, it is critical to have knowledge of the size detection limit (denoted as Dmin) using spICP-MS for a wide range of elements (other than a few available assessed ones) that have been or will be synthesized into engineered nanoparticles. Herein is described a method to estimate the size detection limit using spICP-MS and then apply it to nanoparticles composed of 40 different elements. The calculated Dmin values correspond well for a few of the elements with their detectable sizes that are available in the literature. Assuming each nanoparticle sample is composed of one element, Dmin values vary substantially among the 40 elements: Ta, U, Ir, Rh, Th, Ce, and Hf showed the lowest Dmin values, ≤10 nm; Bi, W, In, Pb, Pt, Ag, Au, Tl, Pd, Y, Ru, Cd, and Sb had Dmin in the range of 11-20 nm; Dmin values of Co, Sr, Sn, Zr, Ba, Te, Mo, Ni, V, Cu, Cr, Mg, Zn, Fe, Al, Li, and Ti were located at 21-80 nm; and Se, Ca, and Si showed high Dmin values, greater than 200 nm. A range of parameters that influence the Dmin, such as instrument sensitivity, nanoparticle density, and background noise, is demonstrated. It is observed that, when the background noise is low, the instrument sensitivity and nanoparticle density dominate the Dmin significantly. Approaches for reducing the Dmin, e.g., collision cell technology (CCT) and analyte isotope selection, are also discussed. To validate the Dmin estimation approach, size distributions for three engineered nanoparticle samples were obtained using spICP-MS. The use of this methodology confirms that the observed minimum detectable sizes are consistent with the calculated Dmin values. Overall, this work identifies the elements and nanoparticles to which current spICP-MS approaches can be applied, in order to enable quantification of very small nanoparticles at low concentrations in aqueous media.

Portable modular detection system

DOEpatents

Brennan, James S [Rodeo, CA; Singh, Anup [Danville, CA; Throckmorton, Daniel J [Tracy, CA; Stamps, James F [Livermore, CA

2009-10-13

Disclosed herein are portable and modular detection devices and systems for detecting electromagnetic radiation, such as fluorescence, from an analyte which comprises at least one optical element removably attached to at least one alignment rail. Also disclosed are modular detection devices and systems having an integrated lock-in amplifier and spatial filter and assay methods using the portable and modular detection devices.

Micromechanical antibody sensor

DOEpatents

Thundat, Thomas G.; Jacobson, K. Bruce; Doktycz, Mitchel J.; Kennel, Stephen J.; Warmack, Robert J.

2001-01-01

A sensor apparatus is provided using a microcantilevered spring element having a coating of a detector molecule such as an antibody or antigen. A sample containing a target molecule or substrate is provided to the coating. The spring element bends in response to the stress induced by the binding which occurs between the detector and target molecules. Deflections of the cantilever are detected by a variety of detection techniques. The microcantilever may be approximately 1 to 200 .mu.m long, approximately 1 to 50 .mu.m wide, and approximately 0.3 to 3.0 .mu.m thick. A sensitivity for detection of deflections is in the range of 0.01 nanometers.

History Detectives Visit NASA Goddard Space Flight Center

NASA Image and Video Library

2017-12-08

The name of the instrument is X-Ray Photoelecton Spectrometer (acronymed XPS); the lab is in the Materials Engineering Branch and aptly titled the X-Ray Photoelectron Spectrometry Lab. XPS is a non-destructive surface analysis technique that provides an elemental composition of the surface. It is capable of detecting any element with the exception of hydrogen and helium. In the picture, I am analyzing a piece of the film that the History Detectives believed was from the Echo II Project. I was looking for the presence of chromium, which would help confirm that the exterior of the film had a chromium conversion coating. PHOTO CREDIT: NASA/Debbie Mccallum

Remote detection of electronic devices

DOEpatents

Judd, Stephen L [Los Alamos, NM; Fortgang, Clifford M [Los Alamos, NM; Guenther, David C [Los Alamos, NM

2012-09-25

An apparatus and method for detecting solid-state electronic devices are described. Non-linear junction detection techniques are combined with spread-spectrum encoding and cross correlation to increase the range and sensitivity of the non-linear junction detection and to permit the determination of the distances of the detected electronics. Nonlinear elements are detected by transmitting a signal at a chosen frequency and detecting higher harmonic signals that are returned from responding devices.

ON THE DETECTION OF GLOBAL 21-cm SIGNAL FROM REIONIZATION USING INTERFEROMETERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Saurabh; Subrahmanyan, Ravi; Shankar, N. Udaya

2015-12-20

Detection of the global redshifted 21-cm signal is an excellent means of deciphering the physical processes during the Dark Ages and subsequent Epoch of Reionization (EoR). However, detection of this faint monopole is challenging due to the high precision required in instrumental calibration and modeling of substantially brighter foregrounds and instrumental systematics. In particular, modeling of receiver noise with mK accuracy and its separation remains a formidable task in experiments aiming to detect the global signal using single-element spectral radiometers. Interferometers do not respond to receiver noise; therefore, here we explore the theory of the response of interferometers to globalmore » signals. In other words, we discuss the spatial coherence in the electric field arising from the monopole component of the 21-cm signal and methods for its detection using sensor arrays. We proceed by first deriving the response to uniform sky of two-element interferometers made of unit dipole and resonant loop antennas, then extend the analysis to interferometers made of one-dimensional arrays and also consider two-dimensional aperture antennas. Finally, we describe methods by which the coherence might be enhanced so that the interferometer measurements yield improved sensitivity to the monopole component. We conclude (a) that it is indeed possible to measure the global 21-cm from EoR using interferometers, (b) that a practically useful configuration is with omnidirectional antennas as interferometer elements, and (c) that the spatial coherence may be enhanced using, for example, a space beam splitter between the interferometer elements.« less

Superior spatial resolution in confocal X-ray techniques using collimating channel array optics: elemental mapping and speciation in archaeological human bone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choudhury, S.; Agyeman-Budu, D. N.; Woll, A. R.

Confocal X-ray fluorescence imaging (CXFI) and confocal X-ray absorption spectroscopy (CXAS) respectively enable the study of three dimensionally resolved localization and speciation of elements. Applied to a thick sample, essentially any volume element of interest within the X-ray fluorescence escape depth can be examined without the need for physical thin sectioning. To date, X-ray confocal detection generally has employed a polycapillary optic in front of the detector to collect fluorescence from the probe volume formed at the intersection of its focus with the incident microfocus beam. This work demonstrates the capability of a novel Collimating Channel Array (CCA) optic inmore » providing an improved and essentially energy independent depth resolution approaching 2 μm. By presenting a comparison of elemental maps of archaeological bone collected without confocal detection, and with polycapillary- and CCA-based confocal detection, this study highlights the strengths and limitations of each mode. Unlike the polycapillary, the CCA shows similar spatial resolution in maps for both low (Ca) and high (Pb and Sr) energy X-ray fluorescence, thus illustrating the energy independent nature of the CCA optic resolution. While superior spatial resolution is demonstrated for all of these elements, the most significant improvement is observed for Ca, demonstrating the advantage of employing the CCA optic in examining light elements. In addition to CXFI, this configuration also enables the collection of Pb L3 CXAS data from micro-volumes with dimensions comparable to bone microstructures of interest. Our CXAS result, which represents the first CCA-based biological CXAS, demonstrates the ability of CCA optics to collect site specific spectroscopic information. The demonstrated combination of site-specific elemental localization and speciation data will be useful in diverse fields.« less

Simultaneous Detection of Electronic Structure Changes from Two Elements of a Bifunctional Catalyst Using Wavelength-Dispersive X-ray Emission Spectroscopy and in situ Electrochemistry

PubMed Central

Gul, Sheraz; Desmond Ng, Jia Wei; Alonso-Mori, Roberto; Kern, Jan; Sokaras, Dimosthenis; Anzenberg, Eitan; Lassalle-Kaiser, Benedikt; Gorlin, Yelena; Weng, Tsu-Chien; Zwart, Petrus H.; Zhang, Jin Z.; Bergmann, Uwe; Yachandra, Vittal K.; Jaramillo, Thomas F.; Yano, Junko

2015-01-01

Multielectron catalytic reactions, such as water oxidation, nitrogen reduction, or hydrogen production in enzymes and inorganic catalysts often involve multimetallic clusters. In these systems, the reaction takes place between metals or metals and ligands to facilitate charge transfer, bond formation/breaking, substrate binding, and release of products. In this study, we present a method to detect X-ray emission signals from multiple elements simultaneously, which allows for the study of charge transfer and the sequential chemistry occurring between elements. Kβ X-ray emission spectroscopy (XES) probes charge and spin states of metals as well as their ligand environment. A wavelength-dispersive spectrometer based on the von Hamos geometry was used to disperse Kβ signals of multiple elements onto a position detector, enabling an XES spectrum to be measured in a single-shot mode. This overcomes the scanning needs of the scanning spectrometers, providing data free from temporal and normalization errors and therefore ideal to follow sequential chemistry at multiple sites. We have applied this method to study MnOx-based bifunctional electrocatalysts for the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). In particular, we investigated the effects of adding a secondary element, Ni, to form MnNiOx and its impact on the chemical states and catalytic activity, by tracking the redox characteristics of each element upon sweeping the electrode potential. The detection scheme we describe here is general and can be applied to time-resolved studies of materials consisting of multiple elements, to follow the dynamics of catalytic and electron transfer reactions. PMID:25747045

Simultaneous detection of electronic structure changes from two elements of a bifunctional catalyst using wavelength-dispersive X-ray emission spectroscopy and in situ electrochemistry.

PubMed

Gul, Sheraz; Ng, Jia Wei Desmond; Alonso-Mori, Roberto; Kern, Jan; Sokaras, Dimosthenis; Anzenberg, Eitan; Lassalle-Kaiser, Benedikt; Gorlin, Yelena; Weng, Tsu-Chien; Zwart, Petrus H; Zhang, Jin Z; Bergmann, Uwe; Yachandra, Vittal K; Jaramillo, Thomas F; Yano, Junko

2015-04-14

Multielectron catalytic reactions, such as water oxidation, nitrogen reduction, or hydrogen production in enzymes and inorganic catalysts often involve multimetallic clusters. In these systems, the reaction takes place between metals or metals and ligands to facilitate charge transfer, bond formation/breaking, substrate binding, and release of products. In this study, we present a method to detect X-ray emission signals from multiple elements simultaneously, which allows for the study of charge transfer and the sequential chemistry occurring between elements. Kβ X-ray emission spectroscopy (XES) probes charge and spin states of metals as well as their ligand environment. A wavelength-dispersive spectrometer based on the von Hamos geometry was used to disperse Kβ signals of multiple elements onto a position detector, enabling an XES spectrum to be measured in a single-shot mode. This overcomes the scanning needs of the scanning spectrometers, providing data free from temporal and normalization errors and therefore ideal to follow sequential chemistry at multiple sites. We have applied this method to study MnOx-based bifunctional electrocatalysts for the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). In particular, we investigated the effects of adding a secondary element, Ni, to form MnNiOx and its impact on the chemical states and catalytic activity, by tracking the redox characteristics of each element upon sweeping the electrode potential. The detection scheme we describe here is general and can be applied to time-resolved studies of materials consisting of multiple elements, to follow the dynamics of catalytic and electron transfer reactions.

Simultaneous detection of electronic structure changes from two elements of a bifunctional catalyst using wavelength-dispersive X-ray emission spectroscopy and in situ electrochemistry

DOE PAGES

Gul, Sheraz; Ng, Jia Wei Desmond; Alonso-Mori, Roberto; ...

2015-02-25

Multielectron catalytic reactions, such as water oxidation, nitrogen reduction, or hydrogen production in enzymes and inorganic catalysts often involve multimetallic clusters. In these systems, the reaction takes place between metals or metals and ligands to facilitate charge transfer, bond formation/breaking, substrate binding, and release of products. In this study, we present a method to detect X-ray emission signals from multiple elements simultaneously, which allows for the study of charge transfer and the sequential chemistry occurring between elements. Kβ X-ray emission spectroscopy (XES) probes charge and spin states of metals as well as their ligand environment. A wavelength-dispersive spectrometer based onmore » the von Hamos geometry was used to disperse Kβ signals of multiple elements onto a position detector, enabling an XES spectrum to be measured in a single-shot mode. This overcomes the scanning needs of the scanning spectrometers, providing data free from temporal and normalization errors and therefore ideal to follow sequential chemistry at multiple sites. We have applied this method to study MnOx-based bifunctional electrocatalysts for the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). In particular, we investigated the effects of adding a secondary element, Ni, to form MnNiOx and its impact on the chemical states and catalytic activity, by tracking the redox characteristics of each element upon sweeping the electrode potential. In conclusion, the detection scheme we describe here is general and can be applied to time-resolved studies of materials consisting of multiple elements, to follow the dynamics of catalytic and electron transfer reactions.« less

Occurrence and Distribution of Iron, Manganese, and Selected Trace Elements in Ground Water in the Glacial Aquifer System of the Northern United States

USGS Publications Warehouse

Groschen, George E.; Arnold, Terri L.; Morrow, William S.; Warner, Kelly L.

2009-01-01

Dissolved trace elements, including iron and manganese, are often an important factor in use of ground water for drinking-water supplies in the glacial aquifer system of the United States. The glacial aquifer system underlies most of New England, extends through the Midwest, and underlies portions of the Pacific Northwest and Alaska. Concentrations of dissolved trace elements in ground water can vary over several orders of magnitude across local well networks as well as across regions of the United States. Characterization of this variability is a step toward a regional screening-level assessment of potential human-health implications. Ground-water sampling, from 1991 through 2003, of the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey determined trace element concentrations in water from 847 wells in the glacial aquifer system. Dissolved iron and manganese concentrations were analyzed in those well samples and in water from an additional 743 NAWQA land-use and major-aquifer survey wells. The samples are from monitoring and water-supply wells. Concentrations of antimony, barium, beryllium, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, selenium, strontium, thallium, uranium, and zinc vary as much within NAWQA study units (local scale; ranging in size from a few thousand to tens of thousands of square miles) as over the entire glacial aquifer system. Patterns of trace element concentrations in glacial aquifer system ground water were examined by using techniques suitable for a dataset with zero to 80 percent of analytical results reported as below detection. During the period of sampling, the analytical techniques changed, which generally improved the analytical sensitivity. Multiple reporting limits complicated the comparison of detections and concentrations. Regression on Order Statistics was used to model probability distributions and estimate the medians and other quantiles of the trace element concentrations. Strontium and barium were the most frequently detected and usually were present in the highest concentrations. Iron and manganese were the next most commonly detected and next highest in concentrations. Iron concentrations were the most variable with respect to the range of variations (both within local networks and aquifer-wide) and with respect to the disparity between magnitude of concentrations (detections) and the frequency of samples below reporting limits (nondetections). Antimony, beryllium, cadmium, silver, and thallium were detected too infrequently for substantial interpretation of their occurrence or distributions or potential human-health implications. For those elements that were more frequently detected, there are some geographic patterns in their occurrence that primarily reflect climate effects. The highest concentrations of several elements were found in the West-Central glacial framework area (High Plains and northern Plains areas). There are few important patterns for any element in relation to land use, well type, or network type. Shallow land-use (monitor) wells had iron concentrations generally lower than the glacial aquifer system wells overall and much lower than major-aquifer survey wells, which comprise mostly private- and public-supply wells. Unlike those for iron, concentration patterns for manganese were similar among shallow land-use wells and major-aquifer survey wells. An apparent relation between low pH and relatively low concentrations of many elements, except lead, may be more indicative of the relatively low dissolved-solids content in wells in the Northeastern United States that comprise the majority of low pH wells, than of a pH dependent pattern. Iron and manganese have higher concentrations and larger ranges of concentrations especially under more reducing conditions. Dissolved oxygen and well depth were related to iron and manganese concentrations. Redox conditions also affect several trace elements such

Tactile sensor of hardness recognition based on magnetic anomaly detection

NASA Astrophysics Data System (ADS)

Xue, Lingyun; Zhang, Dongfang; Chen, Qingguang; Rao, Huanle; Xu, Ping

2018-03-01

Hardness, as one kind of tactile sensing, plays an important role in the field of intelligent robot application such as gripping, agricultural harvesting, prosthetic hand and so on. Recently, with the rapid development of magnetic field sensing technology with high performance, a number of magnetic sensors have been developed for intelligent application. The tunnel Magnetoresistance(TMR) based on magnetoresistance principal works as the sensitive element to detect the magnetic field and it has proven its excellent ability of weak magnetic detection. In the paper, a new method based on magnetic anomaly detection was proposed to detect the hardness in the tactile way. The sensor is composed of elastic body, ferrous probe, TMR element, permanent magnet. When the elastic body embedded with ferrous probe touches the object under the certain size of force, deformation of elastic body will produce. Correspondingly, the ferrous probe will be forced to displace and the background magnetic field will be distorted. The distorted magnetic field was detected by TMR elements and the output signal at different time can be sampled. The slope of magnetic signal with the sampling time is different for object with different hardness. The result indicated that the magnetic anomaly sensor can recognize the hardness rapidly within 150ms after the tactile moment. The hardness sensor based on magnetic anomaly detection principal proposed in the paper has the advantages of simple structure, low cost, rapid response and it has shown great application potential in the field of intelligent robot.

The Tolypocladium inflatum CPA element encodes a RecQ helicase-like gene.

PubMed

Kempken, Frank

2008-12-01

Previously, a repetitive CPA element was discovered in the genome of the filamentous fungus Tolypocladium inflatum; however, no further characterization was technically possible at that time. In this study, PCR amplification was used to detect a 4 kb conserved portion of the CPA element that appeared to be present in most, if not all, genomic CPA elements. The amplicons included a large open reading frame that was most similar to a RecQ helicase-like gene from Metarhizium anisopliae. The repetitive nature of the CPA element suggests that it is related to the eukaryotic Helitron class of transposable elements.

Simple and direct method for detecting phosphorus in air at normal pressure and temperature using a combination of LIBS and LIFS techniques

NASA Astrophysics Data System (ADS)

Al-Jeffery, Mohammad O.; Kondou, H.; Belenkevitch, Alexander; Azzeer, Abdallah M.

2002-05-01

The Environmental Protection Agency (EAP) designated phosphorus as hazardous material; it is flammable and poisonous. Phosphorus attacks the respiratory system, liver, kidneys, jaw, teeth, blood, eyes, and skin. Phosphorus is an element that has a high detection limit when using laser-induced breakdown spectroscopy (LIBS) techniques. In order to improve on detection limits, laser-induced fluorescence spectroscopy (LIFS) has been proposed, as an extension to LIBS. The ultimate goal of this work is to use the combined LIBS & LIFS techniques to detect the presence of phosphorus in air and to measure its level. In order to provide 'proof-of-concept' results, the sample used for our experiment was prepared using the 'igniting' strip of a safety match box. The spectrally and temporally resolved detection of the specific atomic emission revealed analytical information about the elemental composition of the sample. A tunable Ti: sapphire laser, at the resonance wavelength of 253.4 nm, was then used to probe the plume by exciting the phosphorus element and we measured the fluorescence from the atoms at 213.62 nm and 214.91 nm. The whole experiment was carried out in a few minutes. We have thus demonstrated for the first time, to our knowledge, the use of LIBS and LIFS in air quality monitoring and in particular for phosphorus detection.

Computational Approaches to Identify Promoters and cis-Regulatory Elements in Plant Genomes1

PubMed Central

Rombauts, Stephane; Florquin, Kobe; Lescot, Magali; Marchal, Kathleen; Rouzé, Pierre; Van de Peer, Yves

2003-01-01

The identification of promoters and their regulatory elements is one of the major challenges in bioinformatics and integrates comparative, structural, and functional genomics. Many different approaches have been developed to detect conserved motifs in a set of genes that are either coregulated or orthologous. However, although recent approaches seem promising, in general, unambiguous identification of regulatory elements is not straightforward. The delineation of promoters is even harder, due to its complex nature, and in silico promoter prediction is still in its infancy. Here, we review the different approaches that have been developed for identifying promoters and their regulatory elements. We discuss the detection of cis-acting regulatory elements using word-counting or probabilistic methods (so-called “search by signal” methods) and the delineation of promoters by considering both sequence content and structural features (“search by content” methods). As an example of search by content, we explored in greater detail the association of promoters with CpG islands. However, due to differences in sequence content, the parameters used to detect CpG islands in humans and other vertebrates cannot be used for plants. Therefore, a preliminary attempt was made to define parameters that could possibly define CpG and CpNpG islands in Arabidopsis, by exploring the compositional landscape around the transcriptional start site. To this end, a data set of more than 5,000 gene sequences was built, including the promoter region, the 5′-untranslated region, and the first introns and coding exons. Preliminary analysis shows that promoter location based on the detection of potential CpG/CpNpG islands in the Arabidopsis genome is not straightforward. Nevertheless, because the landscape of CpG/CpNpG islands differs considerably between promoters and introns on the one side and exons (whether coding or not) on the other, more sophisticated approaches can probably be developed for the successful detection of “putative” CpG and CpNpG islands in plants. PMID:12857799

CAFNA{reg{underscore}sign}, coded aperture fast neutron analysis for contraband detection: Preliminary results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, L.; Lanza, R.C.

1999-12-01

The authors have developed a near field coded aperture imaging system for use with fast neutron techniques as a tool for the detection of contraband and hidden explosives through nuclear elemental analysis. The technique relies on the prompt gamma rays produced by fast neutron interactions with the object being examined. The position of the nuclear elements is determined by the location of the gamma emitters. For existing fast neutron techniques, in Pulsed Fast Neutron Analysis (PFNA), neutrons are used with very low efficiency; in Fast Neutron Analysis (FNS), the sensitivity for detection of the signature gamma rays is very low.more » For the Coded Aperture Fast Neutron Analysis (CAFNA{reg{underscore}sign}) the authors have developed, the efficiency for both using the probing fast neutrons and detecting the prompt gamma rays is high. For a probed volume of n{sup 3} volume elements (voxels) in a cube of n resolution elements on a side, they can compare the sensitivity with other neutron probing techniques. As compared to PFNA, the improvement for neutron utilization is n{sup 2}, where the total number of voxels in the object being examined is n{sup 3}. Compared to FNA, the improvement for gamma-ray imaging is proportional to the total open area of the coded aperture plane; a typical value is n{sup 2}/2, where n{sup 2} is the number of total detector resolution elements or the number of pixels in an object layer. It should be noted that the actual signal to noise ratio of a system depends also on the nature and distribution of background events and this comparison may reduce somewhat the effective sensitivity of CAFNA. They have performed analysis, Monte Carlo simulations, and preliminary experiments using low and high energy gamma-ray sources. The results show that a high sensitivity 3-D contraband imaging and detection system can be realized by using CAFNA.« less

[Spectroscopic methods applied to component determination and species identification for coffee].

PubMed

Chen, Hua-zhou; Xu, Li-li; Qin, Qiang

2014-06-01

Spectroscopic analysis was applied to the determination of the nutrient quality of ground, instant and chicory coffees. By using inductively coupled plasma atomic emission spectrometry (ICP-ES), nine mineral elements were determined in solid coffee samples. Caffeine was determined by ultraviolet (UV) spectrometry and organic matter was investigated by Fourier transform infrared (FTIR) spectroscopy. Oxidation-reduction titration was utilized for measuring the oxalate. The differences between ground coffee and instant coffee was identified on the basis of the contents of caffeine, oxalate and mineral elements. Experimental evidence showed that, caffeine in instant coffee was 2-3 times higher than in ground coffee. Oxalate in instant coffee was significantly higher in ground coffee. Mineral elements of Mg, P and Zn in ground coffee is lower than in instant coffee, while Cu is several times higher. The mineral content in chicory coffee is overall lower than the instant coffee. In addition, we determined the content of Ti for different types of coffees, and simultaneously detected the elements of Cu, Ti and Zn in chicory coffee. As a fast detection technique, FTIR spectroscopy has the potential of detecting the differences between ground coffee and instant coffee, and is able to verify the presence of caffeine and oxalate.

Submicron hard X-ray fluorescence imaging of synthetic elements.

PubMed

Jensen, Mark P; Aryal, Baikuntha P; Gorman-Lewis, Drew; Paunesku, Tatjana; Lai, Barry; Vogt, Stefan; Woloschak, Gayle E

2012-04-13

Synchrotron-based X-ray fluorescence microscopy (XFM) using hard X-rays focused into sub-micron spots is a powerful technique for elemental quantification and mapping, as well as microspectroscopic measurements such as μ-XANES (X-ray absorption near edge structure). We have used XFM to image and simultaneously quantify the transuranic element plutonium at the L(3) or L(2)-edge as well as Th and lighter biologically essential elements in individual rat pheochromocytoma (PC12) cells after exposure to the long-lived plutonium isotope (242)Pu. Elemental maps demonstrate that plutonium localizes principally in the cytoplasm of the cells and avoids the cell nucleus, which is marked by the highest concentrations of phosphorus and zinc, under the conditions of our experiments. The minimum detection limit under typical acquisition conditions with an incident X-ray energy of 18 keV for an average 202 μm(2) cell is 1.4 fg Pu or 2.9×10(-20) moles Pu μm(-2), which is similar to the detection limit of K-edge XFM of transition metals at 10 keV. Copper electron microscopy grids were used to avoid interference from gold X-ray emissions, but traces of strontium present in naturally occurring calcium can still interfere with plutonium detection using its L(α) X-ray emission. Copyright © 2012 Elsevier B.V. All rights reserved.

Premature terminator analysis sheds light on a hidden world of bacterial transcriptional attenuation.

PubMed

Naville, Magali; Gautheret, Daniel

2010-01-01

Bacterial transcription attenuation occurs through a variety of cis-regulatory elements that control gene expression in response to a wide range of signals. The signal-sensing structures in attenuators are so diverse and rapidly evolving that only a small fraction have been properly annotated and characterized to date. Here we apply a broad-spectrum detection tool in order to achieve a more complete view of the transcriptional attenuation complement of key bacterial species. Our protocol seeks gene families with an unusual frequency of 5' terminators found across multiple species. Many of the detected attenuators are part of annotated elements, such as riboswitches or T-boxes, which often operate through transcriptional attenuation. However, a significant fraction of candidates were not previously characterized in spite of their unmistakable footprint. We further characterized some of these new elements using sequence and secondary structure analysis. We also present elements that may control the expression of several non-homologous genes, suggesting co-transcription and response to common signals. An important class of such elements, which we called mobile attenuators, is provided by 3' terminators of insertion sequences or prophages that may be exapted as 5' regulators when inserted directly upstream of a cellular gene. We show here that attenuators involve a complex landscape of signal-detection structures spanning the entire bacterial domain. We discuss possible scenarios through which these diverse 5' regulatory structures may arise or evolve.

Fast analysis of wood preservers using laser induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Uhl, A.; Loebe, K.; Kreuchwig, L.

2001-06-01

Laser-induced breakdown spectroscopy (LIBS) is used for the investigation of wood preservers in timber and in furniture. Both experiments in laboratory and practical applications in recycling facilities and on a building site prove the new possibilities for the fast detection of harmful agents in wood. A commercial system was developed for mobile laser-plasma-analysis as well as for industrial use in sorting plants. The universal measuring principle in combination with an Echelle optics permits real simultaneous multi-element-analysis in the range of 200-780 nm with a resolution of a few picometers. It enables the user to detect main and trace elements in wood within a few seconds, nearly independent of the matrix, knowing that different kinds of wood show an equal elemental composition. Sample preparation is not required. The quantitative analysis of inorganic wood preservers (containing, e.g. Cu, Cr, B, As, Pb, Hg) has been performed exactly using carbon as reference element. It can be shown that the detection limits for heavy metals in wood are in the ppm-range. Additional information is given concerning the quantitative analysis. Statistical data, e.g. the standard deviation (S.D.), were determined and calibration curves were used for each particular element. A comparison between ICP-AES and LIBS is given using depth profile correction factors regarding the different penetration depths with respect to the different volumes in wood analyzed by both analytical methods.

PROTON MICROPROBE ANALYSIS OF TRACE-ELEMENT VARIATIONS IN VITRINITES IN THE SAME AND DIFFERENT COAL BEDS.

USGS Publications Warehouse

Minkin, J.A.; Chao, E.C.T.; Blank, Herma; Dulong, F.T.

1987-01-01

The PIXE (proton-induced X-ray emission) microprobe can be used for nondestructive, in-situ analyses of areas as small as those analyzed by the electron microprobe, and has a sensitivity of detection as much as two orders of magnitude better than the electron microprobe. Preliminary studies demonstrated that PIXE provides a capability for quantitative determination of elemental concentrations in individual coal maceral grains with a detection limit of 1-10 ppm for most elements analyzed. Encouraged by the earlier results, we carried out the analyses reported below to examine trace element variations laterally (over a km range) as well as vertically (cm to m) in the I and J coal beds in the Upper Cretaceous Ferron Sandstone Member of the Mancos Shale in central Utah, and to compare the data with the data from two samples of eastern coals of Pennsylvanian age.

Volatile organic compounds and trace metal level in some beers collected from Romanian market

NASA Astrophysics Data System (ADS)

Voica, Cezara; Kovacs, Melinda; Vadan, Marius

2013-11-01

Beer is one of the most popular beverages at worldwide level. Through this study fifteen different types of beer collected from Romanian market were analysed in order to evaluate their mineral, trace element as well the their organic content. Importance of such characterization of beer samples is supported by the fact that their chemical composition can affect both taste and stability of beer, as well the consumer health. Minerals and trace elements analysis were performed on ICP-MS while organic compounds analysis was done through GC-MS. Through ICP-MS analysis, elements as Ca, Na, K and Mg were evidenced at mgṡkg-1 order while elements as Cr, Ba, Co, Ni were detected at lower level. After GC-MS analysis the major volatile compounds that were detected belong to alcohols namely ethanol, propanol, isobutanol, isoamyl alcohol and linalool. Selected fatty acids and esters were evidenced also in the studied beer samples.

Multiple groups of orientation-selective visual mechanisms underlying rapid orientated-line detection.

PubMed Central

Foster, D H; Westland, S

1998-01-01

Visual search for an edge or line element differing in orientation from a background of other edge or line elements can be performed rapidly and effortlessly. In this study, based on psychophysical measurements with ten human observers, threshold values of the angle between a target and background line elements were obtained as functions of background-element orientation, in brief masked displays. A repeated-loess analysis of the threshold functions suggested the existence of several groups of orientation-selective mechanisms contributing to rapid orientated-line detection; specifically, coarse, intermediate and fine mechanisms with preferred orientations spaced at angles of approximately 90 degrees, 35 degrees, and 10 degrees-25 degrees, respectively. The preferred orientations of coarse and some intermediate mechanisms coincided with the vertical or horizontal of the frontoparallel plane, but the preferred orientations of fine mechanisms varied randomly from observer to observer, possibly reflecting individual variations in neuronal sampling characteristics. PMID:9753784

Annual suspended sediment and trace element fluxes in the Mississippi, Columbia, Colorado, and Rio Grande drainage basins

USGS Publications Warehouse

Horowitz, A.J.; Elrick, K.A.; Smith, J.J.

2001-01-01

Suspended sediment, sediment-associated, total trace element, phosphorus (P), and total organic carbon (TOC) fluxes were determined for the Mississippi, Columbia, Rio Grande, and Colorado Basins for the study period (the 1996, 1997, and 1998 water years) as part of the US Geological Survey's redesigned National Stream Quality Accounting Network (NASQAN) programme. The majority (??? 70%) of Cu, Zn, Cr, Ni, Ba, P, As, Fe, Mn, and Al are transported in association with suspended sediment; Sr transport seems dominated by the dissolved phase, whereas the transport of Li and TOC seems to be divided equally between both phases. Average dissolved trace element levels are markedly lower than reported during the original NASQAN programme; this seems due to the use of 'clean' sampling, processing, and analytical techniques rather than to improvements in water quality. Partitioning between sediment and water for Ag, Pb, Cd, Cr, Co, V, Be, As, Sb, Hg, and Ti could not be estimated due to a lack of detectable dissolved concentrations in most samples. Elevated suspended sediment-associated Zn levels were detected in the Ohio River Basin and elevated Hg levels were detected in the Tennessee River, the former may affect the mainstem Mississippi River, whereas the latter probably do not. Sediment-associated concentrations of Ag, Cu, Pb, Zn, Cd, Cr, Co, Ba, Mo, Sb, Hg, and Fe are markedly elevated in the upper Columbia Basin, and appear to be detectable (Zn, Cd) as far downstream as the middle of the basin. These elevated concentrations seem to result from mining and/or mining-related activities. Consistently detectable concentrations of dissolved Se were found only in the Colorado River Basin. Calculated average annual suspended sediment fluxes at the mouths of the Mississippi and Rio Grande Basins were below, whereas those for the Columbia and Colorado Basins were above previously published annual values. Downstream suspended sediment-associated and total trace element fluxes increase in the Mississippi and Columbia Basins, whereas fluxes markedly decrease in the Colorado Basin. No consistent pattern in trace element fluxes was detected in the Rio Grande Basin.

Detection of boron, cobalt, and other weak interstellar lines toward Zeta Ophiuchi

NASA Technical Reports Server (NTRS)

Federman, S. R.; Sheffer, Y.; Lambert, D. L.; Gilliland, R. L.

1993-01-01

Numerous weak lines from interstellar atomic species toward Zeta Ophiuchi were observed with the Goddard High-Resolution Spectrograph. Of particular note are the first interstellar detection of cobalt and the detection of boron in this sight line. These measurements provide estimates for the amount of depletion for the two elements. Boron, a volatile, and cobalt, a refractory element, display the depletion pattern found by Savage et al. (1992). The abundance of phosphorus in the H II region associated with the star was obtained from a detection of P III. Additional weak lines from S I, C I, Ni II, and Cu II were detected for the first time; these lines provide the basis for refinements in oscillator strength and column density. Analysis of the neutral sulfur data indicates that the atomic gas is more widely distributed than the molecular material in the main component.

Helium microwave-induced plasmas for element specific detection in chromatography

NASA Astrophysics Data System (ADS)

Long, Gary L.; Ducatte, Gerald R.; Lancaster, Edwin D.

1994-01-01

This review addresses the development and use of the microwave-induced plasma (MIP) using optical emission spectrometry for the purpose of element specific detection in chromatography. The plasma source that is the focus of this article is the He-based MIP operated at atmospheric pressure. The forms of chromatography that are covered include gas chromatography, liquid chromatography, and supercritical fluid chromatography. Concepts in plasma cavity design and the chromatograph-plasma interface are discussed along with the application of these hybrid systems to analytical determinations.

Identification of elemental mercury in the subsurface

DOEpatents

Jackson, Dennis G

2015-01-06

An apparatus and process is provided for detecting elemental mercury in soil. A sacrificial electrode of aluminum is inserted below ground to a desired location using direct-push/cone-penetrometer based equipment. The insertion process removes any oxides or previously found mercury from the electrode surface. Any mercury present adjacent the electrode can be detected using a voltmeter which indicates the presence or absence of mercury. Upon repositioning the electrode within the soil, a fresh surface of the aluminum electrode is created allowing additional new measurements.

DIFFERENTIAL FAULT SENSING CIRCUIT

DOEpatents

Roberts, J.H.

1961-09-01

A differential fault sensing circuit is designed for detecting arcing in high-voltage vacuum tubes arranged in parallel. A circuit is provided which senses differences in voltages appearing between corresponding elements likely to fault. Sensitivity of the circuit is adjusted to some level above which arcing will cause detectable differences in voltage. For particular corresponding elements, a group of pulse transformers are connected in parallel with diodes connected across the secondaries thereof so that only voltage excursions are transmitted to a thyratron which is biased to the sensitivity level mentioned.

Enhanced Vibrational Echo Correlation Spectrometer for the Study of Molecular Dynamics, Structures, and Analytical Applications

DTIC Science & Technology

2006-09-10

ultrafast IR 2D vibrational echo spectrometer. The major improvement involved a new dual MCT array detector composed of two 32 x 1 element MCT IR... detector arrays. The dual array makes it possible to improve signal- to- noise ratio in the heterodyne detection of the vibrational echo signal. To...are dispersed in a monochromator and then detected with the new 2x32-element MCT IR array detector . As discussed above, the function of the local

Detection of Bioaerosols Using Single Particle Thermal Emission Spectroscopy (First-year Report)

DTIC Science & Technology

2012-02-01

cooled MCT detector with a noise equivalent power (NEP) of 7x10(–13) W/Hz, yields a detection S/N > 13 (assuming a sufficiently cooled background). We...dispersively resolved using 190-mm Horiba spectrometer that houses a time-gated 32-element mercury cadmium telluride ( MCT ) linear array. In this report...to 10.0 ms. Minimum integration (and readout) periods for the time-gated 32-element mercury cadmium telluride ( MCT ) linear array are 10 µs. Based

Application of an X-ray Fluorescence Instrument to Helicopter Wear Debris Analysis

DTIC Science & Technology

2008-04-01

from magnesium (Mg) to uranium (U) using two X-ray detection sensors: a FOCUS 5+ detector AlX-ray tube X-ray Detector 1. Incident X-ray...zinc (Zn), whilst the PIN detector is used to detect elements from calcium (Ca) to uranium (U) [4]. Elements between calcium (Ca) to zinc (Zn) can be... carbide paper, however polishing is not a normal sample preparation requirement for the Twin-X (see Figure 16). The samples were placed polished side

Semiconductor neutron detector

DOEpatents

Ianakiev, Kiril D [Los Alamos, NM; Littlewood, Peter B [Cambridge, GB; Blagoev, Krastan B [Arlington, VA; Swinhoe, Martyn T [Los Alamos, NM; Smith, James L [Los Alamos, NM; Sullivan, Clair J [Los Alamos, NM; Alexandrov, Boian S [Los Alamos, NM; Lashley, Jason Charles [Santa Fe, NM

2011-03-08

A neutron detector has a compound of lithium in a single crystal form as a neutron sensor element. The lithium compound, containing improved charge transport properties, is either lithium niobate or lithium tantalate. The sensor element is in direct contact with a monitor that detects an electric current. A signal proportional to the electric current is produced and is calibrated to indicate the neutrons sensed. The neutron detector is particularly useful for detecting neutrons in a radiation environment. Such radiation environment may, e.g. include gamma radiation and noise.

Trace elements and organic contaminants in stream sediments from the Red River of the North Basin

USGS Publications Warehouse

Brigham, M.E.; Tornes, L.H.

1996-01-01

To assess the presence and distribution of a variety of hydro-phobic chemicals in streams in the Red River of the North Basin, bottom sediments were analyzed for trace elements, organochlorines, and polycyclic aromatic hydrocarbons (PAHs). Glaciolacustrine clays and carbonate minerals are common in fine sediments of the region, and can help explain the distribution of many elements. Aluminum (Al), an indicator of glaciolacustrine clay minerals, correlates strongly (r>0.75, p<0.05) with Cr, Co, Fe, La, Li, K, Sc, and Ti; and moderately (0.55

A novel microbial fuel cell sensor with biocathode sensing element.

PubMed

Jiang, Yong; Liang, Peng; Liu, Panpan; Wang, Donglin; Miao, Bo; Huang, Xia

2017-08-15

The traditional microbial fuel cell (MFC) sensor with bioanode as sensing element delivers limited sensitivity to toxicity monitoring, restricted application to only anaerobic and organic rich water body, and increased potential fault warning to the combined shock of organic matter/toxicity. In this study, the biocathode for oxygen reduction reaction was employed for the first time as the sensing element in MFC sensor for toxicity monitoring. The results shown that the sensitivity of MFC sensor with biocathode sensing element (7.4±2.0 to 67.5±4.0mA% -1 cm -2 ) was much greater than that showed by bioanode sensing element (3.4±1.5 to 5.5±0.7mA% -1 cm -2 ). The biocathode sensing element achieved the lowest detection limit reported to date using MFC sensor for formaldehyde detection (0.0005%), while the bioanode was more applicable for higher concentration (>0.0025%). There was a quicker response of biocathode sensing element with the increase of conductivity and dissolved oxygen (DO). The biocathode sensing element made the MFC sensor directly applied to clean water body monitoring, e.g., drinking water and reclaimed water, without the amending of background organic matter, and it also decreased the warning failure when challenged by a combined shock of organic matter/toxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparision of ICP-OES and MP-AES in determing soil nutrients by Mechlich3 method

NASA Astrophysics Data System (ADS)

Tonutare, Tonu; Penu, Priit; Krebstein, Kadri; Rodima, Ako; Kolli, Raimo; Shanskiy, Merrit

2014-05-01

Accurate, routine testing of nutrients in soil samples is critical to understanding soil potential fertility. There are different factors which must be taken into account selecting the best analytical technique for soil laboratory analysis. Several techniques can provide adequate detection range for same analytical subject. In similar cases the choise of technique will depend on factors such as sample throughput, required infrastructure, ease of use, used chemicals and need for gas supply and operating costs. Mehlich 3 extraction method is widely used for the determination of the plant available nutrient elements contents in agricultural soils. For determination of Ca, K, and Mg from soil extract depending of laboratory ICP and AAS techniques are used, also flame photometry for K in some laboratories. For the determination of extracted P is used ICP or Vis spectrometry. The excellent sensitivity and wide working range for all extracted elements make ICP a nearly ideal method, so long as the sample throughput is big enough to justify the initial capital outlay. Other advantage of ICP techniques is the multiplex character (simultaneous acquisition of all wavelengths). Depending on element the detection limits are in range 0.1 - 1000 μg/L. For smaller laboratories with low sample throughput requirements the use of AAS is more common. Flame AAS is a fast, relatively cheap and easy technique for analysis of elements. The disadvantages of the method is single element analysis and use of flammable gas, like C2H2 and oxidation gas N2O for some elements. Detection limits of elements for AAS lays from 1 to 1000 μg/L. MP-AES offers a unique alternative to both, AAS and ICP-OES techniques with its detection power, speed of analysis. MP-AES is quite new, simple and relatively inexpensive multielemental technique, which is use self-sustained atmospheric pressure microwave plasma (MP) using nitrogen gas generated by nitrogen generator. Therefore not needs for argon and flammable (C2H2) gases, cylinder handling and the running costs of equipment are low. Detection limits of elements for MP-AES lays between the AAS and ICP ones. The objective of this study was to compare the results of soil analysis using two multielemental analytical methods - ICP-OES and MP-AES. In the experiment, different soil types with various texture, content of organic matter and pH were used. For the study soil samples of Albeluvisols, Leptosols, Cambisols, Regosols and Histosols were used . The plant available nutrients were estimated by Mehlich 3 extraction. The ICP-OES analysis were provided in the Estonian Agricultural Research Centre and MP-AES analysis in department of Soil Science and Agrochemistry at Estonian University of Life Sciences. The detection limits and limits of quantification of Ca, K, Mg and P in extracts are calculated and reported.

Evaluating Trends in Historical PM2.5 Element Concentrations by Reanalyzing a 15-Year Sample Archive

NASA Astrophysics Data System (ADS)

Hyslop, N. P.; White, W. H.; Trzepla, K.

2014-12-01

The IMPROVE (Interagency Monitoring of PROtected Visual Environments) network monitors aerosol concentrations at 170 remote sites throughout the United States. Twenty-four-hour filter samples of particulate matter are collected every third day and analyzed for chemical composition. About 30 of the sites have operated continuously since 1988, and the sustained data record (http://views.cira.colostate.edu/web/) offers a unique window on regional aerosol trends. All elemental analyses have been performed by Crocker Nuclear Laboratory at the University of California in Davis, and sample filters collected since 1995 are archived on campus. The suite of reported elements has remained constant, but the analytical methods employed for their determination have evolved. For example, the elements Na - Mn were determined by PIXE until November 2001, then by XRF analysis in a He-flushed atmosphere through 2004, and by XRF analysis in vacuum since January 2005. In addition to these fundamental changes, incompletely-documented operational factors such as detector performance and calibration details have introduced variations in the measurements. Because the past analytical methods were non-destructive, the archived filters can be re-analyzed with the current analytical systems and protocols. The 15-year sample archives from Great Smoky Mountains (GRSM), Mount Rainier (MORA), and Point Reyes National Parks (PORE) were selected for reanalysis. The agreement between the new analyses and original determinations varies with element and analytical era. The graph below compares the trend estimates for all the elements measured by IMPROVE based on the original and repeat analyses; the elements identified in color are measured above the detection limit more than 90% of the time. The trend estimates are sensitive to the treatment of non-detect data. The original and reanalysis trends are indistinguishable (have overlapping confidence intervals) for most of the well-detected elements.

Sensitive elemental detection using microwave-assisted laser-induced breakdown imaging

NASA Astrophysics Data System (ADS)

Iqbal, Adeel; Sun, Zhiwei; Wall, Matthew; Alwahabi, Zeyad T.

2017-10-01

This study reports a sensitive spectroscopic method for quantitative elemental detection by manipulating the temporal and spatial parameters of laser-induced plasma. The method was tested for indium detection in solid samples, in which laser ablation was used to generate a tiny plasma. The lifetime of the laser-induced plasma can be extended to hundreds of microseconds using microwave injection to remobilize the electrons. In this novel method, temporal integrated signal of indium emission was significantly enhanced. Meanwhile, the projected detectable area of the excited indium atoms was also significantly improved using an interference-, instead of diffraction-, based technique, achieved by directly imaging microwave-enhanced plasma through a novel narrow-bandpass filter, exactly centered at the indium emission line. Quantitative laser-induce breakdown spectroscopy was also recorded simultaneously with the new imaging method. The intensities recorded from both methods exhibit very good mutual linear relationship. The detection intensity was improved to 14-folds because of the combined improvements in the plasma lifetime and the area of detection.

Electro-optical muzzle flash detection

NASA Astrophysics Data System (ADS)

Krieg, Jürgen; Eisele, Christian; Seiffer, Dirk

2016-10-01

Localizing a shooter in a complex scenario is a difficult task. Acoustic sensors can be used to detect blast waves. Radar technology permits detection of the projectile. A third method is to detect the muzzle flash using electro-optical devices. Detection of muzzle flash events is possible with focal plane arrays, line and single element detectors. In this paper, we will show that the detection of a muzzle flash works well in the shortwave infrared spectral range. Important for the acceptance of an operational warning system in daily use is a very low false alarm rate. Using data from a detector with a high sampling rate the temporal signature of a potential muzzle flash event can be analyzed and the false alarm rate can be reduced. Another important issue is the realization of an omnidirectional view required on an operational level. It will be shown that a combination of single element detectors and simple optics in an appropriate configuration is a capable solution.