Several neutron capture cross sections of light nuclei (A {<=} 40) for neutron energies up to the MeV region have been recently calculated. Examples are (target nuclei): {sup 12}C, {sup 13}C, {sup 16}O and {sup 10}Be. The results of these calculations will be shown together with a comparison with the most recent experimental data. In the case of n + {sup 10}Be case, the cross section of the inverse process (Coulomb dissociation of {sup 11}Be) is considered and compared with the measurement. A discussion on the relevant nuclear structure information required for the evaluation of nuclear data of light nuclei is given. (author)
Possibility of a crossed-beam experiment involving slow-neutron capture by unstable nuclei - ``rapid-process tron''
The possibility of a crossed beam facility of slow neutrons capturing unstable nuclei is examined in connection with the Japanese Hadron Project. With a pulsed proton beam of 50 Hz repetition and with a 100 Î¼A average beam current, one obtains a spallation neutron source of 2.4 Ã— 10 8 thermal neutrons/cm 3/spill over a 60 cm length with a 3 ms average duration time by using a D 2O moderator. By confining radioactive nuclei of 10 9 ions in a beam circulation ring of 0.3 MHz revolution frequency, so that nuclei pass through the neutron source, one obtains a collision luminosity of 3.9 Ã— 10 24/cm 2/s. A new research domain aimed at studying rapid processes in nuclear genetics in a laboratory will be created.
Experimental investigations on the synthesis and study of properties of faraway transactinide elements confirm the predictions of macro-microscopic theory on the existence of closed shells in the region of heavy deformed nuclei. It has been demonstrated experimentally that nuclear structure plays a decisive role in the stability of superheavy nuclides. Based on the experimental confirmation of the main provisions of the theory and after the introduction of a necessary correction into the calculation the properties of heavier nuclides in the region of spherical shells Z=114 and N=180-184 have been predicted. Here a substantial increase in the stability of nuclei is also expected. All the nuclei synthesized by now, were obtained in fusion reactions with a formation of a compound nucleus, the transition of which to the ground state takes place with the emission of neutrons and gamma-rays. Both the reactions of cold and hot fusion of nuclei can be used for the synthesis of new nuclei. Nevertheless, new experimental data on the fusion mechanism are required, since a number of theoretical descriptions of the fusion dynamics of complex nuclear systems need a substantial revising. One can assume that the reactions of the type 244 Pu, 248 Cm + 48 Ca are still within the current potential of the accelerators and experimental technique. This potential, nevertheless, is still to be implemented. 37 refs., 6 figs
The astrophysical S-factors of thermonuclear reactions, including radiative capture reactions and their analysis in the frame of different theoretical models, are the main source of nuclear processes. We have done research on the radiative capture reactions importance in the framework of a potential model. Investigation of the reactions in the astrophysical energies is of great interest in the aspect of astrophysics and nuclear physics for developing correct models of burning and evolution of stars. The experimental measurements are very difficult and impossible because of these reactions occurrence at low-energies. In this paper we do a calculation on radiative capture astrophysical S-factors for nuclei in the mass region A theoretical methods.
This work is devoted to the search for highly deformed nuclei under extreme conditions of isospin, located near the proton drip-line, around A âˆ¼ 130. The experiment was performed at GANIL (Caen) with the SPIRAL radioactive beam facility. The nuclei of interest were produced by fusion-evaporation reactions induced by the neutron deficient Kr 76 radioactive beam (T1/2 = 14.8 h). Î³-rays were detected by the EXOGAM array, composed of 11 segmented germanium clover detectors, for which a new segment calibration method has been developed. To extract fusion-evaporation events of a overwhelming background due to the radioactivity of the beam, the EXOGAM array was coupled with the light charged particle detector DIAMANT and the high acceptance VAMOS spectrometer. The latter was used for the first time to detect fusion-evaporation residues. The detailed data analysis allowed us to demonstrate that the EXOGAM + DIAMANT + VAMOS coupling is operational and essential to investigate the structure of these nuclei. Furthermore, the first Î³ transition was observed in the very exotic odd-odd Pm 130 nucleus. The results have been interpreted with static and dynamic self-consistent microscopic calculations in collaboration with the Theoretical Physicists of the IPN Lyon. (author)
This work is devoted to the search for highly deformed nuclei under extreme conditions of isospin, located near the proton drip-line, around Aâˆ¼130. The experiment was performed at GANIL (Caen) with the SPIRAL radioactive beam facility. The nuclei of interest were produced by fusion-evaporation reactions induced by the neutron deficient 76 Kr radioactive beam (T 1/2 = 14.8 h). Î³-rays were detected by the EXOGAM array, composed of 11 segmented germanium clover detectors, for which a new segment calibration method has been developed. To extract fusion-evaporation events of a overwhelming background due to the radioactivity of the beam, the EXOGAM array was coupled with the light charged particle detector DIAMANT and the high acceptance VAMOS spectrometer. The latter was used for the first time to detect fusion-evaporation residues. The detailed data analysis allowed us to demonstrate that the EXOGAM + DIAMANT + VAMOS coupling is operational and essential to investigate the structure of these nuclei. Furthermore, the first Î³ transition was observed in the very exotic odd-odd 130 Pm nucleus. The results have been interpreted with static and dynamic self-consistent microscopic calculations in collaboration with the Theoretical Physicists of the IPN Lyon. (author)
Full text: Understanding of the reaction mechanism with radioactive nuclei, e.g., halo nuclei, at near barrier energies appears to be a challenging problem at present. Recent experimental and theoretical investigations of fusion of exotic nuclei with stable targets have yielded new insights into the structure of these nuclei and its effects on the fusion reaction dynamics. One interesting and intriguing result of this type of study is the controversy over fusion enhancement in the presence of strong break-up channels. Other novel information include an increase of break-up cross-sections and weakening or absence of threshold anomaly, related to energy dependence of optical model potentials, in the neighbourhood of the barrier. It is believed that the coupling of the entrance channel to different non-elastic channels (including break-up) is responsible for the above phenomena and these aspects are more prominent in the near barrier region. An overview of the experimental studies of fusion excitation function with RIB will be presented
Full Text: Understanding of the reaction mechanism with radioactive nuclei, e.g., halo nuclei, at near barrier energies appears to be a challenging problem at present. Recent experimental and theoretical investigations of fusion of exotic nuclei with stable targets have yielded new insights into the structure of these nuclei and its effects on the fusion reaction dynamics. One interesting and intriguing result of this type of study is the controversy over fusion enhancement in the presence of strong break-up channels. Other novel information include an increase of break-up cross-sections and weakening or absence of threshold anomaly, related to energy dependence of optical model potentials, in the neighbourhood of the barrier. It is believed that the coupling of the entrance channel to different non-elastic channels (including break-up) is responsible for the above phenomena and these aspects are more prominent in the near barrier region. An overview of the experimental studies of fusion excitation function with RIB will be presented
Research supported in part by this contract has become totally devoted to the study of far-from-stable radioactive nuclei with the UNISOR facility [University Isotope Separator at Oak Ridge] on-line with HHIRF [Holifield Heavy Ion Research Facility]. The purpose of these UNISOR studies is to investigate the low-spin ( - Î³t, XÎ³t, and Î±Î³t multiparameter coincidence measurements are carried out, and soon measurements of singles Î³-ray angular distributions and magnetic moments of mass-separated, low-temperature oriented nuclei will begin using the helium dilution refrigerator on-line to the isotope separator. In particular, what is reported centers on two neutron-deficient regions of interest, one around the Z = 82 closed shell (from Z = 77 to 85) and the other in the rare earths around the new region of deformation at N 56. 30 refs., 15 figs., 8 tabs
In order to determine the correlations between the following atmospheric parameters: radon and condensation nuclei concentrations, total conductivity and space charge, we analysed their behavior over a long period, in connection with meteorological data. We simulaneously studied the equilibrium state between 222 Rn and its short-lived daughters pointing out a radioactive desequilibrium as a function of the meteorological conditions. Simultaneously, we established average experimental curves of cumulated particle size distributions of natural radioactivity in the air, differentiating urban and marine influences. Finally, a comparison between the various parameters showed that the total conductivity greatly depends on condensation nuclei and radon concentrations in the air [fr
The author presents an example of successfully capturing a hotspot of man-made radioactive 152 Eu in Dayuan when the authors carried out airborne survey for radioactivity levels in north China. The hotspot was on the front of the gate of a concrete pipe factory in Dayuan. The activity of the source was estimated roughly 4.25 x 10 8 -7.53 x 10 8 Bq. The longitudinal positioning error was less than 15 m
The main elements necessary to treat weak interactions in a nucleus including the contributions of exchange meson currents are presented. The case of a transition between an initial (Z,A) nucleus and a final (Z-1,A) nucleus in a well defined bound state is treated. The form of the single body operator taking into account the nucleonic degrees of freedom (impulse approximation) is recalled. The construction of a two-body operator taking mesonic degrees of freedom into account is outlined. Measurements of partial capture rates in 10 B, 12 C and 14 N target nuclei leading to excited bound states of 10 Be, 12 B and 14 C residual nuclei are described. Results are given and comparisons made with the calculations performed, nuclear states being described by various wave functions. Measurements of the polarization of the 1 + ground state of 12 B after N capture in 12 C are briefly described. An attempt is made to interpret the 0 + 1 + transition occurring in the A = 12 triad. A convenient parametrization is obtained from the expression for these observable quantities as a function of the nuclear shape factors. This analysis enables a strict choice to be made from the available wavefunctions. It demonstrates that experimental data are well reproduced by the microscopy approach performed using the effective Sussex potential and single pion exchange currents. Finally, the hitherto unexplored domain of muon capture is tackled. A high energy transfer is involved in which the neutrino remains practically at rest. In this case, the vector part is not very important and the axial current time part contributes as much is the space part. The (Î¼ - ,pn) reaction was used for exploratory measurements in this domain. Practical limits are determined [fr
The results of studies of the excitation of high spin states in stopped Ï€ - -absorption in Nd, Pr, Ce, La and Ba nuclei are reported. States with spins 7 - , 8 - and 19/2 - have been identified. The isomeric ratios for the isotopes 131 Ba and 133 Ba have been determined to be equal to Ïƒsub(m)/Ïƒsub(g)=(5.1+-0.5) and (2.2+-0.3), respectively. For the isomers sup(134m)Cs and sup(135m)Cs the isotopic ratio is found to be Ïƒsub(msub(1))/Ïƒsub(msub(2))=8.2+-2.3. The distinguishing features of the mechanisms of excitation of high spin states by stopped Ï€ - and fast protons are discussed [ru
A novel experimental scheme of electron scattering off unstable nuclei with a self-confining radioactive ion target (SCRIT)
We proposed a new experimental scheme of an electron scattering off unstable nuclei using a Self-Confining Radioactive Ion Target (SCRIT). The SCRIT is an unstable ion target formed in the electron storage ring, and is based on completely new idea. We constructed prototype of the SCRIT device and installed it in the electron storage ring KSR in Kyoto University. In the test experiment, 10 7 -Cs ions are confined in the SCRIT with the lifetime of about 2 s and the feasibility of the SCRIT as the target has been confirmed. (author)
The possibility of using the Wien filter as a mass separator for the neutron enriched nuclei study is under discussion. The nuclei are produced as a result of 238 U fission within the frame of the 'DRIBs' project. The main ion-optics characteristics of the Wien filter are obtained using the moment method. Parameter optimization has been fulfilled to obtain the maximum resolution. The ion beam dynamics and heavy ion separation have been illustrated using the macroparticle simulation for the chosen optimal filter parameter. It is shown that the resolution can be obtained on the level higher than 10 2 . It provides an effective separation of the fission fragments with the high atomic numbers
This work is devoted to the search for highly deformed nuclei under extreme conditions of isospin, located near the proton drip-line, around A {approx} 130. The experiment was performed at GANIL (Caen) with the SPIRAL radioactive beam facility. The nuclei of interest were produced by fusion-evaporation reactions induced by the neutron deficient Kr{sup 76} radioactive beam (T1/2 = 14.8 h). {gamma}-rays were detected by the EXOGAM array, composed of 11 segmented germanium clover detectors, for which a new segment calibration method has been developed. To extract fusion-evaporation events of a overwhelming background due to the radioactivity of the beam, the EXOGAM array was coupled with the light charged particle detector DIAMANT and the high acceptance VAMOS spectrometer. The latter was used for the first time to detect fusion-evaporation residues. The detailed data analysis allowed us to demonstrate that the EXOGAM + DIAMANT + VAMOS coupling is operational and essential to investigate the structure of these nuclei. Furthermore, the first {gamma} transition was observed in the very exotic odd-odd Pm{sup 130} nucleus. The results have been interpreted with static and dynamic self-consistent microscopic calculations in collaboration with the Theoretical Physicists of the IPN Lyon. (author)
Full text: The &apos;Radioactive Ion Beams in Brasil&apos; (RIBRAS) facility consists of two super-conducting solenoids of maxi- mum magnetic field B 6.5T, coupled to the 8UD-Pelletron tandem Accelerator installed at the University of Sao Paulo Physics Institute. It is the first radioactive beam facility of the Southern Hemisphere. The production mechanism of the radioactive ions is by transfer reactions, using {sup 9}Be, {sup 3}He, LiF and other production targets, and the forward focused reaction products are selected and focalized by the solenoids into a scattering chamber. Low energy (3-5 MeV/u) radioactive beams of {sup 6}He, {sup 8}Li, {sup 7,10}Be and {sup 8,12}B are produced currently and used to study elastic, inelastic, and transfer reactions on a variety of light, medium mass and heavy ({sup 9}Be, {sup 12}C, {sup 27}Al, {sup 51}V and {sup 120}Sn) secondary targets. The data are analyzed, using most of the time, the Sao Paulo Potential (SPP) and compared to optical model and continuum discretized coupled-channels (CDCC) calculations. The total reaction cross section as a function of energy has been extracted from the elastic scattering data and the role of breakup of weakly bound or exotic nuclei is discussed. Some examples of reactions recently studied are {sup 1}H({sup 8}Li,{sup 4}He){sup 5}He, {sup 1}H({sup 8}Li,{sup 1}H){sup 8}Li using thick (CH{sub 2}){sub n} targets to measure their excitation functions. The transfer reaction {sup 12}C({sup 8}Li,{sup 4}He){sup 16}N, leading to well defined excited states of {sup 16}N, through the transfer of {sup 4}H or the sequential decay {sup 3}H+n, is also being studied. (author)
The radiative neutron capture cross-section of nuclei has been derived as a function of neutron excess on the basis of the exponential dependence of the cross-section on the reaction energy. It is shown that unknown cross-sections of stable and radioactive nuclei may be evaluated by using the isotonic and isotopic dependence together with available reference cross-section measurements. (author). 4 refs, 3 figs
Comparative assessment of status and opportunities for carbon dioxide capture and storage and radioactive waste disposal In North America
Aside from the target storage regions being underground, geologic carbon sequestration (GCS) and radioactive waste disposal (RWD) share little in common in North America. The large volume of carbon dioxide (CO 2 ) needed to be sequestered along with its relatively benign health effects present a sharp contrast to the limited volumes and hazardous nature of high-level radioactive waste (RW). There is well-documented capacity in North America for 100 years or more of sequestration of CO 2 from coal-fired power plants. Aside from economics, the challenges of GCS include lack of fully established legal and regulatory framework for ownership of injected CO 2 , the need for an expanded pipeline infrastructure, and public acceptance of the technology. As for RW, the USA had proposed the unsaturated tuffs of Yucca Mountain, Nevada, as the region's first high-level RWD site before removing it from consideration in early 2009. The Canadian RW program is currently evolving with options that range from geologic disposal to both decentralized and centralized permanent storage in surface facilities. Both the USA and Canada have established legal and regulatory frameworks for RWD. The most challenging technical issue for RWD is the need to predict repository performance on extremely long time scales (10 4 -10 6 years). While attitudes toward nuclear power are rapidly changing as fossil-fuel costs soar and changes in climate occur, public perception remains the most serious challenge to opening RW repositories. Because of the many significant differences between RWD and GCS, there is little that can be shared between them from regulatory, legal, transportation, or economic perspectives. As for public perception, there is currently an opportunity to engage the public on the benefits and risks of both GCS and RWD as they learn more about the urgent energy-climate crisis created by greenhouse gas emissions from current fossil-fuel combustion practices.
On the theory of beta-radioactivity IV : The polarization of beta-rays emitted by aligned nuclei in allowed transitions
The consequences of alignment of nuclei, which show allowed ÃŸ-transitions, are investigated. A general formula is derived for the transition probability of an allowed Î²-transition, in which the direction of emission of electron and neutrino, the polarization of the electron and the orientation of
The basis for cluster radioactivity is the property of nuclei of light isotopes of elements heavier than lead to spontaneously form clusters - nuclei of light elements - from valence nucleons, which gives rise to asymmetric nuclear molecules. The cluster formation proceeds through successive excitation-free transfer of valence nucleons to the particle and to subsequent light nuclei. Nuclear molecule formation is accompanied by a considerable amount of released energy, which allows quantum-mechanical penetration of the cluster through the exit Coulomb barrier
Proceedings of the workshop nuclear structure of light nuclei far from stability experiment and theory
The volume discuss nuclear structure of light and nuclei far from stability. The discussions took place in five sessions. In session 1 Î² decay, in session 2 nuclei near N=20, in session 3 radioactive ion beams' study with help of electromagnetic separators, in session 4 beta decay of light nuclei, in session 5 further papers were discussed in shell models, binding energy and chart of nuclides. (G.P.)
Nuclear data needs in astrophysics range from neutron capture cross sections of a number of stable or near-stable nuclei to decay and neutron binding-energy data for highly neutron-rich nuclei. LAMPF has the potential to contribute significantly to these needs. The new Los Alamos Neutron Scattering Center (LANSCE, aka WNR/PSR) offers world-class capabilities for neutron capture studies up to an MeV or so. The study of nuclei far from stability could be extended into some regions of astrophysical interest using a proposed He-jet coupled mass separator system with a target/production chamber in the LAMPF beam stop area. Specific examples of possible studies at each facility are presented
Recently, much interest has arisen in the abundance of the s-process isotopes in stars of various metallicity to construct models of the chemical evolution of the Galaxy. Efforts involving both observations and yield estimations of these isotopes are being made for a wide range of metallicities and stellar masses to compare the chemical evolution models with the observational data. So far, in the models of the chemical evolution of the s-isotopes the yields of the isotopes versus the abundance of either 56 Fe (seed) nuclei or 16 O (source) nuclei have been suggested to be linear. However, it has now been shown to be nonlinear for low-metallicity massive stars. The nonlinearity was due to neutron poison by abundant light nuclei. Namely, if the neutron capture cross sections of the light nuclei would be large, the yields of heavier s-isotopes would decrease; the relationship of the yields versus the abundance of either 56 Fe (seed) or 16 O (source) nuclei becomes nonlinear; furthermore, the yields of p-process nuclei would decrease, since the s-process nuclei are the immediate predecessors of the p-nuclei. Therefore, in order to construct models to predict the s- and p-isotope productions as functions of the metallicity and stellar mass, it is necessary to know the neutron capture cross sections of light nuclei at stellar neutron energy. In the lecture, I discuss detailed motive of the study, together with results recently obtained. (author)
Metabolism of neutral lipids in nuclei and chromatin of thymocytes from normal and Î³-irradiated rats
The levels ans specific radioactivities of cholesterol and free fatty acids in nuclei and chromatin of thymocytes from normal and Î³-irradiated (10 Gy) rats have been studied. The radioactivity of the total lipid fraction of Î³-irradiated cells was decreased significantly in the absence of inhibition of [2- 14 C]acetete incorporation into the total proteil and lipid reactions and the [ 3 H]uracyl incorporation into the acid-insoluble RNA. The concentration of free fatty acids in the nuclei increased significantly after irradiation. The specific radioactivity of cholesterol in chromatin was higher than in the nuclei. The differences in specific radioactivities of free fatty acids were less pronounced. After irradiation the ratio of specific radioactivities of free fatty acids in chromatin to that in the nucleai showed a tendency to increase
Hyperfine structure and optical isotope shift measurements have been performed on a series of stable and radioactive strontium isotopes (A = 80 to 90), including two isomers 85m and 87m. The spectroscopy applied continuous wave dye laser induced fluorescence of free atoms at Î»=293.2 nm in a well collimated atomic beam. The 293.2 nm ultraviolet light was generated by frequency doubling the output of a dye laser in either a temperature tuned Ammonium Dihydrogen Arsenate (ADA) crystal or an angle tuned Lithium Iodate crystal. A special radio frequency (rf) technique was used to tune the dye laser frequency with long term stability. Radioactive Sr isotopes were produced either by neutron capture of stable strontium or by (Î±,xn) reactions from krypton gas. The samples were purified by an electromagnetic mass separator and their sizes were of order 100 pg, which corresponds to 10 11 atoms. The observed results of the hyperfine structure components are evaluated in terms of nuclear magnetic dipole moments and electric quadrupole moments. Changes in mean square charge radii of strontium nuclei which were extracted from the isotope shift measurements, exhibit a distinct shell effect at the neutron magic number N=50. The experimental data are analysed and compared with some theoretical nuclear model predictions. The strong increase of the nuclear charge radii with decreasing neutron number of isotopes below N=50 is in agreement with the variation of the mean square deformation extracted from measured B(E2) values. (orig.) [de
This report outlines some of the nuclear structure topics discussed at the Los Alamos Workshop on the Science of Intense Radioactive Ion Beams (RIB). In it we also tried to convey some of the excitement of the participants for utilizing RIBs in their future research. The introduction of radioactive beams promises to be a major milestone for nuclear structure perhaps even more important than the last such advance in beams based on the advent of heavy-ion accelerators in the 1960's. RIBs not only will allow a vast number of new nuclei to be studies at the extremes of isospin, but the variety of combinations of exotic proton and neutron configurations should lead to entirely new phenomena. A number of these intriguing new studies and the profound consequences that they promise for understanding the structure of the atomic nucleus, nature's only many-body, strongly-inteacting quantum system, are discussed in the preceeding sections. However, as with any scientific frontier, the most interesting phenomena probably will be those that are not anticipated--they will be truly new
In this paper isovector excitations in nuclei, in particular the giant isovector quadrupole resonance in spherical nuclei, will be discussed. Several methods to investigate this excitation have been used, e.g. inelastic electron scattering and charge-exchange reactions. An alternative method to study isovector E2 resonances in nuclei, based on the radiative capture of fast neutrons, will be presented. Results from such experiments performed at the tandem accelerator laboratories in Los Alamos and Uppsala will be presented and discussed in terms of the direct-semidirect capture model. As a separate issue, the preparations being undertaken at Uppsala for studies of isovector excitations in nuclei by means of the (n,p) reaction will be described. A schematic lay-out of the experiment will be presented together with some relevant neutron beam parameters. Among isovector excitations to be studied by this method are the isovector monopole resonance and the Gamow-Teller resonance. 54 references, 6 figures, 1 table
Experimental methods using neutron spectroscopy as a means to study the nucleus structure are described. Since reactions of neutron capture (n, Î³) are non-selective, they permit to study the nature of excitation (monoparticle and collective) of nuclear levels, the nature of vibrational excitations, to check the connection between shell model and liquid drop model etc. In many cases (n, Î³) reactions are the only way to check the forecast of nuclear models. Advantages of (n, Î³) spectroscopy, possessing a high precision of measurement and high sensitivity, are underlined. Using neutron spectroscopy on facilities with a high density of neutron flux the structures of energy levels of a large group of nuclei are studied. In different laboratories complete schemes of energy levels of nuclei are obtained, a great number of new levels are found, the evergy level densities are determined, multipolarities of Î³-transitions, spins, level parities are considered. StrUctures of rotational bands of heavy deformed nuclei are studied. The study of the structure of high-spin states is possible only using the methods of (n, Î³) spectroscopy Investigation results of the nuclei 24 Na, 114 Cd, 154 Eu, 155 Cd, 155 Sm, 233 Th are considered as examples. The most interesting aspects of the investigations using neutron spectroscopy are discUssed
The method of prompt Î³-ray data evaluation for thermal-neutron capture has been briefly presented. The prompt capture Î³-ray data of stable nuclei for A = 1 - 25 are evaluated. The evaluated data have been changed into the ENSDF format and the checks of physics and format have been made
filtration of gaseous radioactive substances. It is also necessary to capture and condition the radioactive substances in the exhaust gas from the nuclear plant and equipment and the controlled zones. The second subsystem provides effective control and management of gaseous waste in normal and accidental conditions â€” one of the main issues of nuclear fuel cycle facility design and operation. Many of the issues relating to air cleaning and gaseous radioactive waste management systems have been covered in several IAEA publications. This publication is an attempt to provide systematic and comprehensive information on the entire subject. This publication takes into account the increasing requirements for the protection of the public and the environment, and during the publicationâ€™s preparation, the available technical information was collected and reviewed
Recent improvements in the intensities and optical qualities of radioactive beams have made ... The quality of the data obtained are illustrated with recent results obtained at the GANIL facility for unstable oxygen, sulfur and argon isotopes.
Full Text Available Ultra High Cosmic Rays made by He-like lightest nuclei might solve the AUGER extragalactic clustering along Cen A. Moreover He like UHECR nuclei cannot arrive from Virgo because the light nuclei fragility and opacity above a few Mpc, explaining the Virgo UHECR absence. UHECR signals are spreading along Cen A as observed because horizontal galactic arms magnetic fields, bending them on vertical angles. Cen A events by He-like nuclei are deflected as much as the observed clustered ones; proton will be more collimated while heavy (iron nuclei are too much dispersed. Such a light nuclei UHECR component coexist with the other Auger heavy nuclei and with the Hires nucleon composition. We foresaw (2009 that UHECR He from Cen-A AGN being fragile should partially fragment into secondaries at tens EeV multiplet (D,He3,p nearly as the recent twin multiplet discovered ones (AUGER-ICRC-2011, at 20â€‰EeV along Cen A UHECR clustering. Their narrow crowding occur by a posteriori very low probability, below 3 â‹… 10âˆ’5. Remaining UHECR spread group may hint for correlations with other gamma (MeV âˆ’ Al26â€‰radioactive maps, mainly due to galactic SNR sources as Vela pulsar, the brightest, nearest GeV source. Other nearest galactic gamma sources show links with UHECR via TeV correlated maps. We suggest that UHECR are also heavy radioactive galactic nuclei as Ni56, Ni57 and Co57,Co60 widely bent (tens degree up to â‰¥ 100o by galactic fields. UHECR radioactivity (in Î² and Î³ channels and decay in flight at hundreds keV is boosted (by huge Lorentz factor Î“Ni â‰ƒ 109 âˆ’ 108 leading to PeVs electrons and consequent synchrotron TeVs gamma offering UHECR-TeV correlated sky anisotropy. Moreover also rarest and non-atmospheric Ï„, and e neutrinos secondaries at PeVs, as the first two rarest shower just discovered in ICECUBE, maybe the first signature of such expected radioactive secondary tail.
The work performed under this grant has led to the development of a detection system that will be used to measure reaction rates for proton or neutron capture reactions at stellar energies on radioactive ions far from stability. The reaction rates are needed to better understand the physics of nucleosynthesis in explosive stellar processes such as supernovae and X-ray burst explosions. The radioactive ions will be produced at the Radioactive Ion Beam Facility (RIBF) at RIKEN near Tokyo, Japan. During the course of this work, the group involved in this project has expanded by several institutions in Europe and Japan and now involves collaborators from the U.S., Japan, Hungary, Romania, Germany, Spain, Italy, China, and South Korea. As part of the project, a novel design based on large-area silicon detectors has been built and tested and the performance characterized in a series of tests using particle beams with a variety of atomic numbers at the Cyclotron Institute of Texas A&M University and the Heavy Ion Medical Accelerator in Chiba facility (HIMAC) in Chiba, Japan. The work has involved mechanical construction of a special purpose vacuum chamber, with a precision mounting system for the silicon detectors, development of a new ASICs readout system that has applications with a wide variety of silicon detector systems, and the development of a data acquisition system that is integrated into the computer system being used at RIBF. The parts noted above that are needed to carry out the research program are completed and ready for installation. Several approved experiments that will use this system will be carried out in the near future. The experimental work has been delayed due to a large increase in the cost and availability of electrical power for RIBF that occurred following the massive earthquake and tsunami that hit Japan in the spring of 2011. Another component of the research carried out with this grant involved developing the theoretical tools that are
Murph has now made another nanoparticle breakthrough that could benefit various work environments such as nuclear power plants. Murph and her team have created nanoparticle treated stainless steel filters that are capable to capturing radioactive vapor materials. Just like air filters capture dust and dirt, these filters are capable of capturing large amounts of radioactive vapors. The new research may one day mean that nuclear power plant workers, and other workers in related fields, will have a safer working environment.
Full Text Available Aiming at the problems of on-site plastic bottles recycling and the reuse of waste, the automatic recycling system was developed on the basis of ARM. As the main controller, ARM not only controls the mechanical system of the collector to recover and break plastic bottles, but also communicates with and rewards the user by the automatic reward system through the wireless network. The experimental prototype test results show: post treated fragments of plastic bottles are small, which are convenient to transport and take advantage of; the operation of recovery is easy, and the interface of man-machine interaction is friendly which is easy to expand functions.
Thermophysical characteristics of plastic bottles as an element of water heat accumulators in solar greenhouses
This article considers the thermophysical and granulometric characteristics of polyethylene terephthalate (PET) plastic bottles filled with water. The given figures allow one to conduct calculations of thermal plastic bottles as heat storage elements for solar greenhouses. (author)
This study been carried out to assess the general waste management in Khartoum State and effectively manage the PET plastic bottles by identifying practical means and introducing recycling as cleaner production tool to achieve sustainable development goals. The information data were gathered during the period June-July 2010 through questionnaires, interview, meeting and visits to various sites, in addition to the official information and documents collected from reliable sources, mainly Sudan Central Bank, customs authorities, Ministry of Industry, soft drink and water bottling factories. The data were presented in tables, graphs and charts by applying windows excel program and also applying e view package for the future forecast. Analysis of data shows a rising consumption in PET bottles and the forecasted PET consumption in year 2015 estimated to be 60000 Tons, twice the estimate in the year 2010. This situation will create serious environmental problems that require much more effort to be exerted by all stake holders to book for scientific and practical solutions for the disposal of plastic waste through recycling. Based on the analysis and findings recommendations have been made that ensure on recycling of PET plastic bottles by mechanical method that depends mainly on collection, segregation, cleaning and processing. Further studies and researches on other recycling methods have been recommended in the future. (Author)
Bisphenol A (BPA) is a plastic monomer and plasticizer and is a chemical that has one of the highest volume production worldwide, with more than six billion pounds each year. Its' primary use is the production of polycarbonate plastics, epoxy resins used to line metal cans in a host of plastic consumer products such as toys, water pipes, drinking containers, eyeglass lenses, sports safety equipment as well as consumer electronics. Studies have shown that BPA is leached from lacquer coated cans and baby feeding bottles due to hydrolysis of the Polymer during thermal treatment. Studies have also shown that even under normal use BPA may leach from food and beverage containers. For many years Bisphenol A was treated as neutral to human health. The detection of BPA in drinking water and food products has raised the interest of many researches since 1990. Thousands of studies have examined the impact of BPA to determine its effects in laboratory animals. Numerous toxicological and biochemical studies have supported that BPA has estrogenic properties. The effects of exposure to BPA can be harmful to fetus, infants and young children. BPA is used in products where traces of it can be found in every human at higher levels of concentration than that which causes problems in animals. The National Institute for Environmental Health Sciences (NIEHS) has defined "low dose" of endocrine disrupting chemicals as doses below no observable adverse effect (NOAE) for specific chemicals. In BPA, this dose is 50 mg/kg of body weight per day. Today there are more than 150 published results describing how low doses of BPA effects animals. A recent study reported that adult female mice, monkeys, and humans metabolized BPA at almost identical rates. Since the level of BPA and other endocrine chemicals appears to be increasing throughout the World, especially where plastics are prevalent, it is extremely important to study the effects of this chemical on man and wildlife. This research effort
Highlights: â†’ The PET increased the stiffness level of the mixture improving its resistance level against permanent deformation. â†’ The effects of waste PET on Marshall Stability, air void and bulk specific gravity of the mixture are significant. â†’ The appropriate amount of PET was found to be 6% by weight of bitumen. -- Abstract: Currently, polymer modified asphalt mixture is a relatively costly mixture for paving roads. One way to reduce the cost of such constructions and rendering them more convenient is by using inexpensive polymers, i.e. waste polymers. The main purpose of this research is to determine the effect of incorporating waste plastic bottles (Polyethylene Terephthalate (PET)) on the engineering properties of stone mastic asphalt (SMA) mixture. The volumetric and mechanical properties of asphalt mixes that include various percentages of PET (0%, 2%, 4%, 6%, 8% and 10%) were calculated and assessed with laboratory tests. The appropriate amount of PET was found to be 6% by weight of bitumen. The outcomes were statistically analysed and the determination of the significance at certain confidence limits was performed with the two factor variance analysis (ANOVA). Moreover, some studies conducted on polyethylene modified asphalt mixture have also been taken into consideration in this paper. The results show that the addition of PET has a significant positive effect on the properties of SMA and it can promote the re-use of waste material in industry in an environmentally friendly and economical way.
Antimony is a regulated contaminant that poses both acute and chronic health effects in drinking water. Previous reports suggest that polyethylene terephthalate (PET) plastics used for water bottles in Europe and Canada leach antimony, but no studies on bottled water in the United States have previously been conducted. Nine commercially available bottled waters in the southwestern US (Arizona) were purchased and tested for antimony concentrations as well as for potential antimony release by the plastics that compose the bottles. The southwestern US was chosen for the study because of its high consumption of bottled water and elevated temperatures, which could increase antimony leaching from PET plastics. Antimony concentrations in the bottled waters ranged from 0.095 to 0.521 ppb, well below the US Environmental Protection Agency (USEPA) maximum contaminant level (MCL) of 6 ppb. The average concentration was 0.195+/-0.116 ppb at the beginning of the study and 0.226+/-0.160 ppb 3 months later, with no statistical differences; samples were stored at 22 degrees C. However, storage at higher temperatures had a significant effect on the time-dependent release of antimony. The rate of antimony (Sb) release could be fit by a power function model (Sb(t)=Sb 0 x[Time, h]k; k=8.7 x 10(-6)x[Temperature ( degrees C)](2.55); Sb 0 is the initial antimony concentration). For exposure temperatures of 60, 65, 70, 75, 80, and 85 degrees C, the exposure durations necessary to exceed the 6 ppb MCL are 176, 38, 12, 4.7, 2.3, and 1.3 days, respectively. Summertime temperatures inside of cars, garages, and enclosed storage areas can exceed 65 degrees C in Arizona, and thus could promote antimony leaching from PET bottled waters. Microwave digestion revealed that the PET plastic used by one brand contained 213+/-35 mgSb/kg plastic; leaching of all the antimony from this plastic into 0.5L of water in a bottle could result in an antimony concentration of 376 ppb. Clearly, only a small