Turbulence-driven anisotropic electron tail generation during magnetic reconnection

Science.gov (United States)

DuBois, A. M.; Scherer, A.; Almagri, A. F.; Anderson, J. K.; Pandya, M. D.; Sarff, J. S.

2018-05-01

Magnetic reconnection (MR) plays an important role in particle transport, energization, and acceleration in space, astrophysical, and laboratory plasmas. In the Madison Symmetric Torus reversed field pinch, discrete MR events release large amounts of energy from the equilibrium magnetic field, a fraction of which is transferred to electrons and ions. Previous experiments revealed an anisotropic electron tail that favors the perpendicular direction and is symmetric in the parallel. New profile measurements of x-ray emission show that the tail distribution is localized near the magnetic axis, consistent modeling of the bremsstrahlung emission. The tail appears first near the magnetic axis and then spreads radially, and the dynamics in the anisotropy and diffusion are discussed. The data presented imply that the electron tail formation likely results from a turbulent wave-particle interaction and provides evidence that high energy electrons are escaping the core-localized region through pitch angle scattering into the parallel direction, followed by stochastic parallel transport to the plasma edge. New measurements also show a strong correlation between high energy x-ray measurements and tearing mode dynamics, suggesting that the coupling between core and edge tearing modes is essential for energetic electron tail formation.

Helicopter Control Energy Reduction Using Moving Horizontal Tail

Science.gov (United States)

Oktay, Tugrul; Sal, Firat

2015-01-01

Helicopter moving horizontal tail (i.e., MHT) strategy is applied in order to save helicopter flight control system (i.e., FCS) energy. For this intention complex, physics-based, control-oriented nonlinear helicopter models are used. Equations of MHT are integrated into these models and they are together linearized around straight level flight condition. A specific variance constrained control strategy, namely, output variance constrained Control (i.e., OVC) is utilized for helicopter FCS. Control energy savings due to this MHT idea with respect to a conventional helicopter are calculated. Parameters of helicopter FCS and dimensions of MHT are simultaneously optimized using a stochastic optimization method, namely, simultaneous perturbation stochastic approximation (i.e., SPSA). In order to observe improvement in behaviors of classical controls closed loop analyses are done. PMID:26180841

Helicopter Control Energy Reduction Using Moving Horizontal Tail

Directory of Open Access Journals (Sweden)

Tugrul Oktay

2015-01-01

Full Text Available Helicopter moving horizontal tail (i.e., MHT strategy is applied in order to save helicopter flight control system (i.e., FCS energy. For this intention complex, physics-based, control-oriented nonlinear helicopter models are used. Equations of MHT are integrated into these models and they are together linearized around straight level flight condition. A specific variance constrained control strategy, namely, output variance constrained Control (i.e., OVC is utilized for helicopter FCS. Control energy savings due to this MHT idea with respect to a conventional helicopter are calculated. Parameters of helicopter FCS and dimensions of MHT are simultaneously optimized using a stochastic optimization method, namely, simultaneous perturbation stochastic approximation (i.e., SPSA. In order to observe improvement in behaviors of classical controls closed loop analyses are done.

Distant Tail Behavior During High Speed Solar Wind Streams and Magnetic Storms

Science.gov (United States)

Ho, C. M.; Tsurutani, B. T.

1997-01-01

We have examined the ISEE 3 distant tail data during three intense magnetic storms and have identified the tail response to high-speed solar wind streams, interplanetary magnetic clouds, and near-Earth storms.

Green mines green energy : establishing productive land on mine tailings

Energy Technology Data Exchange (ETDEWEB)

Tisch, B.; Zinck, J.; Vigneault, B. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Mining and Mineral Sciences Laboratories

2008-07-01

Municipal governments and provincial regulators are under increasing pressure to divert clean organic waste materials from landfill sites and establish productive uses for them. This article described the Natural Resources Canada (NRCan) CANMET Green Mines Green Energy consortium. Composed of mining, forestry, government, and academic representatives, the consortium's aim is to expand the use of organic waste residuals in the rehabilitation of mine sites for use as a feedstock in biofuel production. The program's themes include: (1) determining the conditions required to maximize growth; (2) investigating the interaction of various organic covers on tailings pore water, effluent and mineralogy; (3) investigating the potential economic and environmental impacts on all relevant sectors; and (4) disseminating findings to all relevant stakeholders. Tests are currently being conducted to determine the potential impact of municipal waste materials on tailings oxidation and effluent chemistry. The effect of biosolids and compost-derived dissolved organic carbon on effluent treatability and toxicity is also being investigated. Results from the investigations to date suggest that sulfate reduction at the tailings-biosolids interface is taking place. It was concluded that steady state has not yet been reached after a 1 year period. 10 refs., 1 tab., 7 figs.

Characterization and monitoring of transverse beam tails

International Nuclear Information System (INIS)

Seeman, J.T.; Decker, F.J.; Hsu, I.; Young, C.

1991-05-01

Low emittance electron beams accelerated to high energy in a linac experience transverse effects (wakefield, filamentation, optics) which produce non-Gaussian projected transverse beam distributions. Characterizations of the beam shapes are difficult because the shapes are asymmetric and change with betatron phase. In this note several methods to describe beam distributions are discussed including an accelerator physics model of these tails. The uses of these characterizations in monitoring the beam emittances in the SLC are described in this paper. First, two dimensional distributions from profile monitor screens are reviewed showing correlated tails. Second, a fitting technique for non-Gaussian one dimensional distributions is used to extract the core from the tail areas. Finally, a model for tail propagation in the linac is given. 3 refs., 6 figs

Microbial communities in low permeability, high pH uranium mine tailings: characterization and potential effects.

Science.gov (United States)

Bondici, V F; Lawrence, J R; Khan, N H; Hill, J E; Yergeau, E; Wolfaardt, G M; Warner, J; Korber, D R

2013-06-01

To describe the diversity and metabolic potential of microbial communities in uranium mine tailings characterized by high pH, high metal concentration and low permeability. To assess microbial diversity and their potential to influence the geochemistry of uranium mine tailings using aerobic and anaerobic culture-based methods, in conjunction with next generation sequencing and clone library sequencing targeting two universal bacterial markers (the 16S rRNA and cpn60 genes). Growth assays revealed that 69% of the 59 distinct culturable isolates evaluated were multiple-metal resistant, with 15% exhibiting dual-metal hypertolerance. There was a moderately positive correlation coefficient (R = 0·43, P tailings depth was shown to influence bacterial community composition, with the difference in the microbial diversity of the upper (0-20 m) and middle (20-40 m) tailings zones being highly significant (P tailings zone being significant (P tailings environment, along with their demonstrated capacity for transforming metal elements, suggests that these organisms have the potential to influence the long-term geochemistry of the tailings. This study is the first investigation of the diversity and functional potential of micro-organisms present in low permeability, high pH uranium mine tailings. © 2013 The Society for Applied Microbiology.

Preliminary evaluation of uranium mill tailings conditioning as an alternative remedial action technology

International Nuclear Information System (INIS)

Dreesen, D.R.; Cokal, E.J.; Thode, E.F.; Wangen, L.E.; Williams, J.M.

1981-01-01

Conditioning of uranium mill tailings is being investigated as an alternative remedial action for inactive tailings piles to be stabilized by the US Department of Energy. Tailings from high priority sites have been characterized for elemental composition, mineralogy, aqueous leachable contaminants, and radon emanation power to provide a baseline to determine the environmental hazard control produced by conditioning. Thermal stabilization of tailings at high temperatures and removal of contaminants by sulfuric acid leaching are being investigated for technical merit as well as economic and engineering feasibility

Quantization function for attractive, singular potential tails; Die Quantisierungsfunktion fuer attraktive, singulaere Potentialschwaenze

Energy Technology Data Exchange (ETDEWEB)

Raab, Patrick N.

2010-02-04

The interaction between atoms and molecules with each other are deep potential wells with attractive, singular tails. Bound state energies are determined by a quantization function according to a simple quantization rule. This function is dominantly determined by the singular potential tail for near-threshold states. General expressions for the low- and high-energy contributions of the singular potential tail to the quantization function, as well as the connection to the scattering length are presented in two and three dimensions. Precise analytical expressions for the quantization function are determined for the case of potential tails proportional to -1/r{sup 4} and -1/r{sup 6} for three dimensions. (orig.)

Flotation tailings as a raw material for ceramic building materials

Energy Technology Data Exchange (ETDEWEB)

Burmistrov, V N; Karpunina, T I; Smolin, V N

1986-02-01

The VNIIstrom research institute developed a method for utilizing flotation tailings for production of bricks. Tailings are dewatered using filter presses. After dewatering, moisture content in the tailings ranges from 25 to 26%. Tailings are mixed with chamotte with a grain size to 2 mm. Using 30% chamotte improves mechanical and physical properties of the bricks and reduces energy consumption of brick firing. Tailings mixed with chamotte are granulated and dried on a conveyor. Granules with moisture content reduced to the optimum level are mixed a second time and formed in a press. The bricks are fired in a tunnel kiln with modified design. The bricks made of flotation tailings mixed with 30% chamotte are characterized by mechanical properties comparable to those of high quality bricks made of conventional materials.

Canadian experience with uranium tailings disposal

International Nuclear Information System (INIS)

Culver, K.B.

1982-06-01

During the first years of uranium production in Canada uranium tailings were discharged directly into valleys or lakes near the mill. Treatment with barium chloride to precipitate radium began in 1965 at the Nordic Mine at Elliot Lake, Ontario. In the mid-60s and early 70s water quality studies indicated that discharges from uranium tailings areas were causing degradation to the upper part of the Serpent River water system. Studies into acid generation, revegetation, and leaching of radium were initiated by the mining companies and resulted in the construction of treatment plants at a number of sites. Abandoned tailings sites were revegetated. At hearings into the expansion of the Elliot Lake operations the issue of tailings management was a major item for discussion. As a result federal and provincial agencies developed guidelines for the siting and development of urnaium tailings areas prior to issuing operating licences. Western Canadian uranium producers do not have the acid generation problem of the Elliot Lake operations. The Rabbit Lake mill uses settling ponds followed by filtration. High-grade tailings from Cluff Lake are sealed in concrete and buried. Uranium producers feel that the interim criteria developed by the Atomic Energy Control Board, if adopted, would have a harmful effect on the viability of the Canadian uranium industry

Uranium mill tailings

International Nuclear Information System (INIS)

McLaren, L.H.

1982-11-01

This bibliography contains information on uranium mill tailings included in the Department of Energy's Energy Data Base from January 1981 through October 1982. The abstracts are grouped by subject category as shown in the table of contents. Entries in the subject index also facilitate access by subject, e.g., Mill Tailings/Radiation Hazards. Within each category the arrangement is by report number for reports, followed by nonreports in reverse chronological order. These citations are to research reports, journal articles, books, patents, theses, and conference papers from worldwide sources. Five indexes, each preceded by a brief description, are provided: Corporate Author, Personal Author, Subject, Contract Number, and Report Number. (335 abstracts)

(abstract) The Distant Tail Behavior During High Speed Solar Wind Streams and Magnetic Storms

Science.gov (United States)

Ho, C. M.; Tsurutani, B. T.

1996-01-01

We have examined the ISEE-3 distant tail data during three intense magnetic storms and have identified the tail response to high speed solar wind streams, interplanetary magnetic clouds, and near-Earth storms.

Bioassay for uranium mill tailings

International Nuclear Information System (INIS)

Tschaeche, A.N.

1986-01-01

Uranium mill tailings are composed of fine sand that contains, among other things, some uranium (U/sup 238/ primarily), and all of the uranium daughters starting with /sup 230/Th that are left behind after the usable uranium is removed in the milling process. Millions of pounds of tailings are and continue to be generated at uranium mills around the United States. Discrete uranium mill tailings piles exist near the mills. In addition, the tailings materials were used in communities situated near mill sites for such purposes as building materials, foundations for buildings, pipe runs, sand boxes, gardens, etc. The Uranium Mill Tailings Remedial Action Project (UMTRAP) is a U.S. Department of Energy Program designed with the intention of removing or stabilizing the mill tailings piles and the tailings used to communities so that individuals are not exposed above the EPA limits established for such tailings materials. This paper discusses the bioassay programs that are established for workers who remove tailings from the communities in which they are placed

Undifferentiated pleomorphic sarcoma: indolent, tail-like recurrence of a high-grade tumor

Energy Technology Data Exchange (ETDEWEB)

Alpert, Justin S. [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Boland, Patrick [Memorial Sloan Kettering Cancer Center, Division of Orthopaedic Surgery, Department of Surgery, New York, NY (United States); Weill Medical College of Cornell University, New York, NY (United States); Hameed, Meera [Memorial Sloan Kettering Cancer Center, Department of Pathology, New York, NY (United States); Panicek, David M. [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Weill Medical College of Cornell University, New York, NY (United States)

2018-01-15

Recurrence of a soft tissue sarcoma typically manifests as a round or oval mass at imaging, and recurrent high-grade soft tissue sarcomas generally enlarge relatively rapidly. We present a case of high-grade undifferentiated pleomorphic sarcoma in the calf of a 48-year-old male that recurred as a thin, curvilinear ''tail'' of enhancing tissue at magnetic resonance imaging (MRI), with extremely indolent growth over a 7-year period. The unusual imaging finding of a slowly enlarging ''tail'' should not be dismissed as postoperative changes, even for a high-grade soft tissue sarcoma. (orig.)

Reduction of energy cost and CO2 emission for the furnace using energy recovered from waste tail-gas

International Nuclear Information System (INIS)

Jou, Chih-Ju G.; Wu, Chung-Rung; Lee, Chien-Li

2010-01-01

In this research, the waste tail gas emitted from petrochemical processes, e.g. catalytic reforming unit, catalytic cracking unit and residue desulfurization unit, was recovered and reused as a replacement of natural gas (NG). On-site experimental results show that both the flame length and orange-yellowish brightness decrease with more proportion of waste gas fuel added to the natural gas, and that the adiabatic temperature of the mixed fuel is greater than 1800 o C. A complete replacement of natural gas by the recovered waste gas fuel will save 5.8 x 10 6 m 3 of natural gas consumption, and 3.5 x 10 4 tons of CO 2 emission annually. In addition, the reduction of residual O 2 concentration in flue gases from 4% to 3% will save 1.1 x 10 6 m 3 of natural gas consumption, reduce 43.0% of NO x emission, and 1.3 x 10 3 tons of CO 2 emission annually. Thus, from the viewpoint of the overall economics and sustainable energy policy, recovering the waste tail gas energy as an independent fuel source to replace natural gas is of great importance for saving energy, reducing CO 2 emission reduction, and lowering environmental impact.

X-ray absorption intensity at high-energy region

International Nuclear Information System (INIS)

Fujikawa, Takashi; Kaneko, Katsumi

2012-01-01

We theoretically discuss X-ray absorption intensity in high-energy region far from the deepest core threshold to explain the morphology-dependent mass attenuation coefficient of some carbon systems, carbon nanotubes (CNTs), highly oriented pyrolytic graphite (HOPG) and fullerenes (C 60 ). The present theoretical approach is based on the many-body X-ray absorption theory including the intrinsic losses (shake-up losses). In the high-energy region the absorption coefficient has correction term dependent on the solid state effects given in terms of the polarization part of the screened Coulomb interaction W p . We also discuss the tail of the valence band X-ray absorption intensity. In the carbon systems C 2s contribution has some influence on the attenuation coefficient even in the high energy region at 20 keV.

Uranium tailings sampling manual

International Nuclear Information System (INIS)

Feenstra, S.; Reades, D.W.; Cherry, J.A.; Chambers, D.B.; Case, G.G.; Ibbotson, B.G.

1985-01-01

The purpose of this manual is to describe the requisite sampling procedures for the application of uniform high-quality standards to detailed geotechnical, hydrogeological, geochemical and air quality measurements at Canadian uranium tailings disposal sites. The selection and implementation of applicable sampling procedures for such measurements at uranium tailings disposal sites are complicated by two primary factors. Firstly, the physical and chemical nature of uranium mine tailings and effluent is considerably different from natural soil materials and natural waters. Consequently, many conventional methods for the collection and analysis of natural soils and waters are not directly applicable to tailings. Secondly, there is a wide range in the physical and chemical nature of uranium tailings. The composition of the ore, the milling process, the nature of tailings depositon, and effluent treatment vary considerably and are highly site-specific. Therefore, the definition and implementation of sampling programs for uranium tailings disposal sites require considerable evaluation, and often innovation, to ensure that appropriate sampling and analysis methods are used which provide the flexibility to take into account site-specific considerations. The following chapters describe the objective and scope of a sampling program, preliminary data collection, and the procedures for sampling of tailings solids, surface water and seepage, tailings pore-water, and wind-blown dust and radon

Application and Prospect of Superconducting High Gradient Magnetic Separation in Disposal of Micro-fine Tailings

Science.gov (United States)

Yang, Changqiao; Li, Suqin; Guo, Zijie; Kong, Jiawei

2017-12-01

Magnetic separation technology is playing an increasingly important role in the field of environmental protection such as waste gas, waste water and solid waste treatment. As a new type of solid waste treatment technology, superconducting high gradient magnetic separation (HGMS) is mainly applied in the separation of micro-fine weakly magnetic particles because of the advantages of high separation efficiency, energy saving, simple equipment and easy automation. In this paper, the basic principle of superconducting HGMS was firstly introduced, then the research status of scholars at home and aboard on the disposal of micro-fine tailings were summarized. Finally, the direction of development for HGMS was put forward.

ITER alpha particle diagnostics using knock-on ion tails

International Nuclear Information System (INIS)

Fisher, R.K.; Parks, P.B.; McChesney, J.M.

1995-09-01

Alpha particles will play a critical role in the physics and successful operation of ITER. Achieving fusion ignition requires that the α particles created by deuterium-tritium (D-T) reactions deposit a large fraction of their energy in the reacting plasma before they are lost. Toroidal field ripple can localize any alpha particle losses and cause first wall damage. We have proposed a new method of measuring the fast confined α-particle distribution in a reacting plasma. The same elastic collisions that transfer the alpha energy to the D-T plasma ions and allow fusion ignition will also create a high energy tail on the deuterium and tritium ion energy distributions. Some of these energetic tail ions will undergo fusion reactions with the background plasma producing neutrons whose energy is increased significantly above 14 MeV due to the kinetic energy of the reacting ions. Measurement of this high energy tail on the D-T neutron distribution as a function of plasma minor radius would provide information on the alpha density profile with a time response equal to the ion slowing-down time. Although this technique may provide only limited information on the α-particle energy distribution, experimental studies of fast ions on existing tokamaks have shown that the observed slowing-down is essentially classical. Hence the α-energy distribution is expected to be classical except in situations where the α-confinement is poor. The confinement of α's can be affected by ripple losses and a number of instabilities. Toroidal field ripple can cause both prompt orbit losses and stochastic ripple diffusion losses. Magnetohydrodynamic activity, including fishbone instabilities, toroidal Alfven eigenmodes, and sawtooth oscillations, may also affect alpha confinement. The diagnostic proposed here, by monitoring the confined alpha population, can provide valuable information on the confinement of fast alphas in a reacting plasma

The Distant Tail Behavior During High Speed Solar Wind Streams and Magnetic Storms

Science.gov (United States)

Ho, C. M.; Tsurutani, B. T.

1996-01-01

We have examined the ISEE-3 distant tail data during three intense (Dststorms and have identified the tail response to high speed solar wind streams, interplanetary magnetic clouds, and near-Earth storms. The three storms have a peak Dst ranging from -150 to -220 nT, and occur on Jan. 9, Feb. 4, and Aug. 8, 1993.

Reduction of energy cost and CO{sub 2} emission for the furnace using energy recovered from waste tail-gas

Energy Technology Data Exchange (ETDEWEB)

Jou, Chih-Ju G.; Wu, Chung-Rung; Lee, Chien-Li [Department of Safety, Health and Environmental Engineering, National Kaohsiung First University of Science and Technology, No. 2, Jhuoyue Road, Nanzih District, Kaohsiung 811 (China)

2010-03-15

In this research, the waste tail gas emitted from petrochemical processes, e.g. catalytic reforming unit, catalytic cracking unit and residue desulfurization unit, was recovered and reused as a replacement of natural gas (NG). On-site experimental results show that both the flame length and orange-yellowish brightness decrease with more proportion of waste gas fuel added to the natural gas, and that the adiabatic temperature of the mixed fuel is greater than 1800 C. A complete replacement of natural gas by the recovered waste gas fuel will save 5.8 x 10{sup 6} m{sup 3} of natural gas consumption, and 3.5 x 10{sup 4} tons of CO{sub 2} emission annually. In addition, the reduction of residual O{sub 2} concentration in flue gases from 4% to 3% will save 1.1 x 10{sup 6} m{sup 3} of natural gas consumption, reduce 43.0% of NO{sub x} emission, and 1.3 x 10{sup 3} tons of CO{sub 2} emission annually. Thus, from the viewpoint of the overall economics and sustainable energy policy, recovering the waste tail gas energy as an independent fuel source to replace natural gas is of great importance for saving energy, reducing CO{sub 2} emission reduction, and lowering environmental impact. (author)

Feasible conversion of solid waste bauxite tailings into highly crystalline 4A zeolite with valuable application

Energy Technology Data Exchange (ETDEWEB)

Ma, Dongyang; Wang, Zhendong; Guo, Min [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Mei, E-mail: zhangmei@ustb.edu.cn [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China); Liu, Jingbo [The Department of Chemistry, Texas A and M University-Kingsville, Kingsville, TX 78363 (United States); The Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2014-11-15

Highlights: • Concept to convert waste to valuable product is carried out in this study. • An industrially feasible and cost-effective approach was developed and optimized. • Highly crystalline and well-defined zeolite was produced under moderate conditions. • The zeolite derived from the bauxite tailings displayed high ion exchange capacity. • Bauxite tailings have potential application in heavy metal ions adsorbent. - Abstract: Bauxite tailings are a major type of solid wastes generated in the flotation process. The waste by-products caused significant environmental impact. To lessen this hazardous effect from poisonous mine tailings, a feasible and cost-effective solution was conceived and implemented. Our approach focused on reutilization of the bauxite tailings by converting it to 4A zeolite for reuse in diverse applications. Three steps were involved in the bauxite conversion: wet-chemistry, alkali fusion, and crystallization to remove impurities and to prepare porous 4A zeolite. It was found that the cubic 4A zeolite was single phase, in high purity, with high crystallinity and well-defined structure. Importantly, the 4A zeolite displayed maximum calcium ion exchange capacity averaged at 296 mg CaCO{sub 3}/g, comparable to commercially-available zeolite (310 mg CaCO{sub 3}/g) exchange capacity. Base on the optimal synthesis condition, the reaction yield of zeolite 4A from bauxite tailings achieved to about 38.43%, hence, this study will provide a new paradigm for remediation of bauxite tailings, further mitigating the environmental and health care concerns, particularly in the mainland of PR China.

Feasible conversion of solid waste bauxite tailings into highly crystalline 4A zeolite with valuable application

International Nuclear Information System (INIS)

Ma, Dongyang; Wang, Zhendong; Guo, Min; Zhang, Mei; Liu, Jingbo

2014-01-01

Highlights: • Concept to convert waste to valuable product is carried out in this study. • An industrially feasible and cost-effective approach was developed and optimized. • Highly crystalline and well-defined zeolite was produced under moderate conditions. • The zeolite derived from the bauxite tailings displayed high ion exchange capacity. • Bauxite tailings have potential application in heavy metal ions adsorbent. - Abstract: Bauxite tailings are a major type of solid wastes generated in the flotation process. The waste by-products caused significant environmental impact. To lessen this hazardous effect from poisonous mine tailings, a feasible and cost-effective solution was conceived and implemented. Our approach focused on reutilization of the bauxite tailings by converting it to 4A zeolite for reuse in diverse applications. Three steps were involved in the bauxite conversion: wet-chemistry, alkali fusion, and crystallization to remove impurities and to prepare porous 4A zeolite. It was found that the cubic 4A zeolite was single phase, in high purity, with high crystallinity and well-defined structure. Importantly, the 4A zeolite displayed maximum calcium ion exchange capacity averaged at 296 mg CaCO 3 /g, comparable to commercially-available zeolite (310 mg CaCO 3 /g) exchange capacity. Base on the optimal synthesis condition, the reaction yield of zeolite 4A from bauxite tailings achieved to about 38.43%, hence, this study will provide a new paradigm for remediation of bauxite tailings, further mitigating the environmental and health care concerns, particularly in the mainland of PR China

A tale of tails: Photon rates and flow in ultra-relativistic heavy ion collisions

Energy Technology Data Exchange (ETDEWEB)

McLerran, Larry [Physics Dept., Bdg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); Physics Dept., China Central Normal University, Wuhan (China); Schenke, Björn, E-mail: bschenke@quark.phy.bnl.gov [Physics Dept., Bdg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2016-02-15

We consider the possibility that quark and gluon distributions in the medium created in high energy heavy ion collisions may be modified by a power law tail at energies much higher than the temperature. We parametrize such a tail by Tsallis distributions with an exponent motivated by phenomenology. These distributions are characterized by an effective temperature scale that we assume to evolve in time like the temperature for thermal distributions. We find that including such a tail increases the rates for photon production and significantly delays the emission times for photons of a fixed energy. We argue that these effects should modify photon yields and flow patterns in a way that will help the agreement of theoretical calculations with data from LHC and RHIC experiments.

Study of high energy ion loss during hydrogen minority heating in TFTR

International Nuclear Information System (INIS)

Park, J.; Zweben, S.J.

1994-03-01

High energy ion loss during hydrogen minority ICRF heating is measured and compared with the loss of the D-D fusion products. During H minority heating a relatively large loss of high energy ions is observed at 45 degrees below the outer midplane, with or without simultaneous NBI heating. This increase is most likely due to a loss of the minority tail protons, a possible model for this process is described

High energy effects on D-brane and black hole emission rates

International Nuclear Information System (INIS)

Das, S.; Dasgupta, A.; Sarkar, T.

1997-01-01

We study the emission of scalar particles from a class of near-extremal five-dimensional black holes and the corresponding D-brane configuration at high energies. We show that the distribution functions and the black hole greybody factors are modified in the high energy tail of the Hawking spectrum in such a way that the emission rates exactly match. We extend the results to charged scalar emission and to four dimensions. copyright 1997 The American Physical Society

Predicting radon flux from uranium mill tailings

International Nuclear Information System (INIS)

Freeman, H.D.; Hartley, J.N.

1983-11-01

Pacific Northwest Laboratory (PNL), under contract to the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project (UMTRAP) office, is developing technology for the design of radon barriers for uranium mill tailings piles. To properly design a radon cover for a particular tailings pile, the radon flux emanating from the bare tailings must be known. The tailings characteristics required to calculate the radon flux include radium-226 content, emanating power, bulk density, and radon diffusivity. This paper presents theoretical and practical aspects of estimating the radon flux from an uranium tailings pile. Results of field measurements to verify the calculation methodology are also discussed. 24 references, 4 figures, 4 tables

Frost evolution in tailings

International Nuclear Information System (INIS)

1991-04-01

A review was carried out on the physical and thermal mechanisms of permafrost evaluation in soils and uranium tailings. The primary mechanism controlling permafrost evolution is conductive heat transfer with the latent heat of fusion of water being liberated as phase change occurs. Depending on the soil properties and freezing rate, pore water can be expelled from the frost front or pore water can migrate towards the frost front. Solute redistribution may occur as the frost front penetrates into the soil. The rate of frost penetration is a function of the thermal properties of the tailings and the climatic conditions. Computer modelling programmes capable of modelling permafrost evolution were reviewed. The GEOTHERM programme was selected as being the most appropriate for this study. The GEOTHERM programme uses the finite element method of thermal analysis. The ground surface temperature is determined by solving the energy balance equations a the ground surface. The GEOTHERM programme was used to simulate the permafrost evolution in the Key Lake Mine tailings located in north central Saskatchewan. The analyses indicated that the existing frozen zones in the tailing pond will eventually thaw if an average snow depth covers the tailings. Hundreds of years are required to thaw the tailings. If minimal snow cover is present the extent of the frozen zone in the tailings will increase

Angle-resolved photoemission spectroscopy of band tails in lightly doped cuprates

OpenAIRE

Alexandrov, A. S.; Reynolds, K.

2007-01-01

We amend ab initio strongly-correlated band structures by taking into account the band-tailing phenomenon in doped charge-transfer Mott-Hubbard insulators. We show that the photoemission from band tails accounts for sharp "quasi-particle" peaks, rapid loss of their intensities in some directions of the Brillouin zone ("Fermi-arcs") and high-energy "waterfall" anomalies as a consequence of matrix-element effects of disorder-localised states in the charge-transfer gap of doped cuprates.

Value-at-risk estimations of energy commodities via long-memory, asymmetry and fat-tailed GARCH models

International Nuclear Information System (INIS)

Aloui, Chaker; Mabrouk, Samir

2010-01-01

In this paper, we evaluate the value-at-risk (VaR) and the expected shortfalls for some major crude oil and gas commodities for both short and long trading positions. Classical VaR estimations as well as RiskMetrics and other extensions to cases considering for long-range memory, asymmetry and fat-tail in energy markets volatility were conducted. We computed the VaR for three ARCH/GARCH-type models including FIGARCH, FIAPARCH and HYGARCH. These models were estimated in the presence of three alternative innovation's distributions: normal, Student and skewed Student. Our results show that considering for long-range memory, fat-tails and asymmetry performs better in predicting a one-day-ahead VaR for both short and long trading positions. Moreover, the FIAPARCH model outperforms the other models in the VaR's prediction. These results present several potential implications for energy markets risk quantifications and hedging strategies. (author)

A tailing genome walking method suitable for genomes with high local GC content.

Science.gov (United States)

Liu, Taian; Fang, Yongxiang; Yao, Wenjuan; Guan, Qisai; Bai, Gang; Jing, Zhizhong

2013-10-15

The tailing genome walking strategies are simple and efficient. However, they sometimes can be restricted due to the low stringency of homo-oligomeric primers. Here we modified their conventional tailing step by adding polythymidine and polyguanine to the target single-stranded DNA (ssDNA). The tailed ssDNA was then amplified exponentially with a specific primer in the known region and a primer comprising 5' polycytosine and 3' polyadenosine. The successful application of this novel method for identifying integration sites mediated by φC31 integrase in goat genome indicates that the method is more suitable for genomes with high complexity and local GC content. Copyright © 2013 Elsevier Inc. All rights reserved.

Effects of various tailings covers on radon gas emanation from pyritic uranium tailings

International Nuclear Information System (INIS)

Dave, N.K.; Lim, T.P.

1987-01-01

Radon emanation studies were carried out at an inactive pyritic uranium tailings site in Elliot Lake, Ontario, Canada, to evaluate the effects of various existing dry and wet covers on radon flux rates. Measurements were taken using activated charcoal cartridges for various surface covers consisting of bare, vegetated, acidophilic moss with high degree of water saturation, compacted crushed rock and gravel, and winter snow. The results showed that at a given site, there was no significant difference in radon emanation rates between various tailings covers and bare tailings. In particular, no increase In radon emanation rates from vegetated areas compared to bare tailings was observed. Radon emanation rates varied spatially depending on tailings grain size, porosity, moisture content and on pressure and water table variations. The emanation rates were higher for tailings with low water contents compared to those for wet and moss covered tailings

Optical band gap energy and ur bach tail of CdS:Pb2+ thin films

Energy Technology Data Exchange (ETDEWEB)

Chavez, M.; Juarez, H.; Pacio, M. [Universidad Autonoma de Puebla, Instituto de Ciencias, Centro de Investigacion en Dispositivos Semiconductores, Av. 14 Sur, Col. Jardines de San Manuel, Ciudad Universitaria, Puebla, Pue. (Mexico); Gutierrez, R.; Chaltel, L.; Zamora, M.; Portillo, O. [Universidad Autonoma de Puebla, Facultad de Ciencias Quimicas, Laboratorio de Materiales, Apdo. Postal 1067, 72001 Puebla, Pue. (Mexico); Mathew, X., E-mail: osporti@yahoo.mx [UNAM, Instituto de Energias Renovables, Temixco, Morelos (Mexico)

2016-11-01

Pb S-doped CdS nano materials were successfully synthesized using chemical bath. Transmittance measurements were used to estimate the optical band gap energy. Tailing in the band gap was observed and found to obey Ur bach rule. The diffraction X-ray show that the size of crystallites is in the ∼33 nm to 12 nm range. The peaks belonging to primary phase are identified at 2θ = 26.5 degrees Celsius and 2θ = 26.00 degrees Celsius corresponding to CdS and Pb S respectively. Thus, a shift in maximum intensity peak from 2θ = 26.4 to 28.2 degrees Celsius is clear indication of possible transformation of cubic to hexagonal phase. Also peaks at 2θ = 13.57, 15.9 degrees Celsius correspond to lead perchlorate thiourea. The effects on films thickness and substrate doping on the band gap energy and the width on tail were investigated. Increasing doping give rise to a shift in optical absorption edge ∼0.4 eV. (Author)

Flip, flop and fly: modulated motor control and highly variable movement patterns of autotomized gecko tails.

Science.gov (United States)

Higham, Timothy E; Russell, Anthony P

2010-02-23

Many animals lose and regenerate appendages, and tail autotomy in lizards is an extremely well-studied example of this. Whereas the energetic, ecological and functional ramifications of tail loss for many lizards have been extensively documented, little is known about the behaviour and neuromuscular control of the autotomized tail. We used electromyography and high-speed video to quantify the motor control and movement patterns of autotomized tails of leopard geckos (Eublepharis macularius). In addition to rhythmic swinging, we show that they exhibit extremely complex movement patterns for up to 30 min following autotomy, including acrobatic flips up to 3 cm in height. Unlike the output of most central pattern generators (CPGs), muscular control of the tail is variable and can be arrhythmic. We suggest that the gecko tail is well suited for studies involving CPGs, given that this spinal preparation is naturally occurring, requires no surgery and exhibits complex modulation.

Uranium mill tailings remedial action technology

International Nuclear Information System (INIS)

Hartley, J.N.; Gee, G.W.

1984-01-01

The uranium milling process involves the hydrometallurgical extraction of uranium from ores and the resultant generation of large quantities of waste referred to as tailings. Uranium mill tailings have been identified as requiring remediation because they contain residual radioactive material that is not removed in the milling process. Potential radiation exposure can result from direct contact with the tailings, from radon gas emitted by the tailings, and from radioactive contamination of groundwater. As a result, the technology developed under the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project (UMTRAP) and the US Nuclear Regulatory Commission (NRC) Uranium Recovery Program have focused on radon control, groundwater contamination and the long-term protection of the containment system. This paper briefly summarizes the UMTRAP and NRC remedial action technology development. 33 references, 9 figures, 5 tables

High energy neutrinos to see inside the Earth

International Nuclear Information System (INIS)

Borriello, E.; De Lellis, G.; Mangano, G.

2010-01-01

The new chances offered by elementary particles as probes of the internal structure of our planet are briefly reviewed, by paying particular attention to the case of high energy neutrinos. In particular, the new results concerning the shadow of mountains on ν τ flux at Pierre Auger Observatory is briefly discussed, and moreover the possibility to use the tail of atmospheric neutrinos to probe the core/mantle transition region is just sketched. (author)

THE ELECTROMAGNETIC MODEL OF SHORT GRBs, THE NATURE OF PROMPT TAILS, SUPERNOVA-LESS LONG GRBs, AND HIGHLY EFFICIENT EPISODIC ACCRETION

Energy Technology Data Exchange (ETDEWEB)

Lyutikov, Maxim [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907-2036 (United States)

2013-05-01

and interpret the prompt tail as an energetic long GRB (the supernova-less long burst GRB060505 and GRB060614 may belong to this category). We also demonstrate that episodic accretion onto the black hole of magnetized clouds that carry non-zero magnetic flux can be highly efficient in extracting the spin energy of the black hole, producing the electromagnetic outflows with power exceeding the average M-dot c{sup 2} accretion power and total energy exceeding the rest mass energy of the accreted mass. We identify the late time flares with such accretion events.

Neoclassical transport of energetic minority tail ions generated by ion-cyclotron resonance heating in tokamak geometry

International Nuclear Information System (INIS)

Chang, C.S.; Hammett, G.W.; Goldston, R.J.

1990-01-01

Neoclassical transport of energetic minority tail ions, which are generated by high powered electromagnetic waves of the Ion Cyclotron Range of Frequencies (ICRF) at the fundamental harmonic resonance, is studied analytically in tokamak geometry. The effect of Coulomb collisions on the tail ion transport is investigated in the present work. The total tail ion transport will be the sum of the present collision-driven transport and the wave-driven transport, which is due to the ICRF-wave scattering of the tail particles as reported in the literature. The transport coefficients have been calculated kinetically, and it is found that the large tail ion viscosity, driven by the localized ICRF-heating and Coulomb slowing-down collisions, induces purely convective particle transport of the tail species, while the energy transport is both convective and diffusive. The rate of radial particle transport is shown to be usually small, but the rate of radial energy transport is larger and may not be negligible compared to the Coulomb slowing-down rate. 18 refs., 2 figs

Segregation and differential settling in flocculated tailings

Energy Technology Data Exchange (ETDEWEB)

Farinato, R.S.; Mahmoudkhani, A.; Fenderson, T.; Watson, P. [Kemira, Atlanta, GA (United States)

2010-07-01

Untreated oil sands tailings have a high solids content, have poor dewaterability, and contain no aggregates. This PowerPoint presentation investigated segregation and differential settling in flocculated tailings. Tailings were treated with gypsum and various polymers. Cylinder settling, dynamic rheometry, particle size analysis, and microscopy techniques were used to characterize the composite tailings. The particles sizes of the samples were evaluated in relation to shear rate, bed depth, and treatment. The study showed that the gypsum-treated tailings had small aggregates, size stratification, a high solids content, and poor dewaterability. The polymer N-treated tailings had the lowest solids content, good dewaterability, and weak aggregates. The polymer A-treated tailings had a low solids content, very good dewaterability, and strong aggregates. The addition of a coagulant to the polymer-A treated tailings provided weaker aggregates and a higher solids content. tabs., figs.

Feasible conversion of solid waste bauxite tailings into highly crystalline 4A zeolite with valuable application.

Science.gov (United States)

Ma, Dongyang; Wang, Zhendong; Guo, Min; Zhang, Mei; Liu, Jingbo

2014-11-01

Bauxite tailings are a major type of solid wastes generated in the flotation process. The waste by-products caused significant environmental impact. To lessen this hazardous effect from poisonous mine tailings, a feasible and cost-effective solution was conceived and implemented. Our approach focused on reutilization of the bauxite tailings by converting it to 4A zeolite for reuse in diverse applications. Three steps were involved in the bauxite conversion: wet-chemistry, alkali fusion, and crystallization to remove impurities and to prepare porous 4A zeolite. It was found that the cubic 4A zeolite was single phase, in high purity, with high crystallinity and well-defined structure. Importantly, the 4A zeolite displayed maximum calcium ion exchange capacity averaged at 296 mg CaCO3/g, comparable to commercially-available zeolite (310 mg CaCO3/g) exchange capacity. Base on the optimal synthesis condition, the reaction yield of zeolite 4A from bauxite tailings achieved to about 38.43%, hence, this study will provide a new paradigm for remediation of bauxite tailings, further mitigating the environmental and health care concerns, particularly in the mainland of PR China. Copyright © 2014 Elsevier Ltd. All rights reserved.

Formation of the high-energy ion population in the earth's magnetotail: spacecraft observations and theoretical models

Directory of Open Access Journals (Sweden)

A. V. Artemyev

2014-10-01

Full Text Available We investigate the formation of the high-energy (E ∈ [20,600] keV ion population in the earth's magnetotail. We collect statistics of 4 years of Interball / Tail observations (1995–1998 in the vicinity of the neutral plane in the magnetotail region (X RE, |Y| ≤ 20 RE in geocentric solar magnetospheric (GSM system. We study the dependence of high-energy ion spectra on the thermal-plasma parameters (the temperature Ti and the amplitude of bulk velocity vi and on the magnetic-field component Bz. The ion population in the energy range E ∈ [20,600] keV can be separated in the thermal core and the power-law tail with the slope (index ~ −4.5. Fluxes of the high-energy ion population increase with the growth of Bz, vi and especially Ti, but spectrum index seems to be independent on these parameters. We have suggested that the high-energy ion population is generated by small scale transient processes, rather than by the global reconfiguration of the magnetotail. We have proposed the relatively simple and general model of ion acceleration by transient bursts of the electric field. This model describes the power-law energy spectra and predicts typical energies of accelerated ions.

Reclamation and closure of an oil sands tailings facility

Energy Technology Data Exchange (ETDEWEB)

Sobkowicz, J. [Thurber Engineering Ltd., Calgary, AB (Canada); Morgenstern, N. [Alberta Univ., Edmonton, AB (Canada)

2010-07-01

This PowerPoint presentation discussed methods of ensuring the successful reclamation of oil sands tailings facilities. Tailings should be reclaimed as mining proceeds in order to avoid an excessive accumulation of fluid fine tailings (FFT). The volume of mature fine tailings (MFT) in ponds should be limited in order to ensure effective tailings management. The reclaimed landforms should have good geotechnical stability and be comprised of self-sustaining native vegetation. Strength is needed to allow for timely capping and initial reclamation, and stiffness is required to minimize future settlement and to allow for the construction of a closure landscape. Reclamation strategies were presented for fines-dominated tailings; sand-depleted tailings; and sand-dominated tailings. Energy Resources Conservation Board (ERCB) criteria for tailings reclamation were discussed, and various monitoring and performance assessment strategies were presented. tabs., figs.

Sub-stratum injection of fine tailings

Energy Technology Data Exchange (ETDEWEB)

Kesteren van, W.; Cornelisse, J.; Costello, M. [Deltares, Delft (Netherlands)

2010-07-01

This PowerPoint presentation discussed an experiment conducted to evaluate the sub-stratum injection of oil sands fine tailings. The hydraulic fracturing method was developed as a sub-surface dredging process for mining sand without removing the overburden. Pressure was used to transport the sand-water mixture, and the high pressures used in the process resulted in water losses through the clay-sand interface. The experiment was conducted with soft clay, compacted sand, and an injection feed. Results of the study showed that the injection method may be successful. However, further research is required to characterize the fracture energy of oil sands and the rheology of fine tailings. Horizontal hydraulic fracturing equations were presented. Tensile failures in clay and oil sands were discussed. Fractures were identified by deformation and discharge rates. Crack propagation methods were also studied. tabs., figs.

Energy resources of the west tailings pond, Airline-Sponsler Mine, Greene County, Indiana

Energy Technology Data Exchange (ETDEWEB)

Eggert, D.L.; Miller, L.V.; Irwin, P.N.

1980-12-01

The west tailings pond at the Airline-Sponsler Mine is a manmade prograding fan-delta system in which wastes from preparing coal are deposited in expected sequences. The tailings pond, originally a surface-mine final-cut and haulage road, is about 10,000 feet long, 200 to 300 feet wide, and 25 to 60 feet deep. The Indiana Geological Survey drilled eight auger holes at the pond. The first hole was 50 feet from the entry point, the second hole was 200 feet from the first, and the remaining six holes were 700 feet apart. At each hole samples were taken on 5-foot intervals, and a composite sample of each hole was also prepared. Coarse coal, dense rock fragments, and sulfide minerals settle first and are followed by medium to fine coal and clay and very fine coal. At the entry point ash is high (65.4 percent), sulfur is high (12 percent), calorific value is low (3220 Btu), and particle size is large. At the distal end ash is low near the surface but increases near the base (15.5 to 59.3 percent), sulfur is high near the surface but decreases near the base (2.6 to 1.0 percent), calorific value is high near the surface but decreases near the base (12,000 to 5250 Btu), and particle size is large near the surface but decreases near the base. Washability determinations indicate that some tailings located distally to the entry point might be reclaimed as a fuel with little further preparation and those located proximally could be upgraded by further preparation.

Electroweak precision tests in high-energy diboson processes

Science.gov (United States)

Franceschini, Roberto; Panico, Giuliano; Pomarol, Alex; Riva, Francesco; Wulzer, Andrea

2018-02-01

A promising avenue to perform precision tests of the SM at the LHC is to measure differential cross-sections at high invariant mass, exploiting in this way the growth with the energy of the corrections induced by heavy new physics. We classify the leading growing-with-energy effects in longitudinal diboson and in associated Higgs production processes, showing that they can be encapsulated in four real "high-energy primary" parameters. We assess the reach on these parameters at the LHC and at future hadronic colliders, focusing in particular on the fully leptonic W Z channel that appears particularly promising. The reach is found to be superior to existing constraints by one order of magnitude, providing a test of the SM electroweak sector at the per-mille level, in competition with LEP bounds. Unlike LHC run-1 bounds, which only apply to new physics effects that are much larger than the SM in the high-energy tail of the distributions, the probe we study applies to a wider class of new physics scenarios where such large departures are not expected.

Application of a life cycle assessment to compare environmental performance in coal mine tailings management.

Science.gov (United States)

Adiansyah, Joni Safaat; Haque, Nawshad; Rosano, Michele; Biswas, Wahidul

2017-09-01

This study compares coal mine tailings management strategies using life cycle assessment (LCA) and land-use area metrics methods. Hybrid methods (the Australian indicator set and the ReCiPe method) were used to assess the environmental impacts of tailings management strategies. Several strategies were considered: belt filter press (OPT 1), tailings paste (OPT 2), thickened tailings (OPT 3), and variations of OPT 1 using combinations of technology improvement and renewable energy sources (OPT 1A-D). Electrical energy was found to contribute more than 90% of the environmental impacts. The magnitude of land-use impacts associated with OPT 3 (thickened tailings) were 2.3 and 1.55 times higher than OPT 1 (tailings cake) and OPT 2 (tailings paste) respectively, while OPT 1B (tailings belt filter press with technology improvement and solar energy) and 1D (tailings belt press filter with technology improvement and wind energy) had the lowest ratio of environmental impact to land-use. Further analysis of an economic cost model and reuse opportunities is required to aid decision making on sustainable tailings management and industrial symbiosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Commingled uranium-tailings study. Volume II. Technical report

Energy Technology Data Exchange (ETDEWEB)

None

1982-06-30

Public Law 96-540, Section 213, directs the Secretary of Energy to develop a plan for a cooperative program to provide assistance in the stabilization and management of defense-related uranium mill tailings commingled with other tailings. In developing the plan, the Secretary is further directed to: (1) establish the amount and condition of tailings generated under federal contracts; (2) examine appropriate methodologies for establishing the extent of federal assistance; and (3) consult with the owners and operators of each site. This technical report summarizes US Department of Energy (DOE) and contractor activities in pursuit of items (1), (2), and (3) above. Recommendations regarding policy and a cooperative plan for federal assistance are under separate cover as Volume I.

Sub-aerial tailings deposition

International Nuclear Information System (INIS)

Knight, R.B.; Haile, J.P.

1984-01-01

The sub-aerial technique involves the systematic deposition of tailings in thin layers and allowing each layer to settle, drain and partially air dry prior to covering with a further layer. Underdrainage produces densities in excess of those achieved by sub-aqueous deposition and any air-drying serves to preconsolidate each layer with a resulting further increase in density. The low permeability of the tailings surface resulting from this deposition technique results in high runoff coefficients and, by decanting the runoff component of direct precipitation, a net evaporation condition can be achieved even in high rainfall areas. An underdrainage system prevents the build-up of excess pore-pressures within the tailings mass and at decommissioning the tailings are fully consolidated and drained thereby eliminating the possibility of any long term seepage. This paper presents a general description of these design concepts, and details of two projects where the concepts have been applied

Research on the characterization and conditioning of uranium mill tailings. III. Summary of uranium mill tailings conditioning research and implications regarding remedial actions

International Nuclear Information System (INIS)

Dreesen, D.R.; Cokal, E.J.; Thode, E.F.; Williams, J.M.

1983-06-01

This report summarizes the findings of research on uranium mill tailings conditioning technology development performed for the Department of Energy's (DOE) Uranium Mill Tailings Remedial Action Project (UMTRAP). Hazards and risks posed by tailings piles are discussed in relation to the goal of conditioning the tailings to reduce these hazards. The results of our efforts regarding characterization of tailings, removal of radionuclides, mineral recovery, thermal stabilization, and engineering/economic analysis of conditioning are presented. The implications of these results for remedial action plans are discussed and conclusions regarding the applicability of these technologies are also presented

Tail posture predicts tail damage among weaned piglets

NARCIS (Netherlands)

Zonderland, J.J.; Riel, van J.W.; Bracke, M.B.M.; Kemp, B.; Hartog, den L.A.; Spoolder, H.A.M.

2009-01-01

Tail biting in pigs is a widespread behavioural vice with significant animal welfare and economic consequences. All too often, tail biting is not diagnosed nor dealt with until tail damage is present. To effectively reduce the negative effects of tail biting, it must be diagnosed in an early stage.

Near-IR High-Resolution Imaging Polarimetry of the SU Aur Disk: Clues for Tidal Tails?

Science.gov (United States)

De Leon, Jerome; Michihiro, Takami; Karr, Jennifer; Hashimoto, Jun; Kudo, Tomoyuki; Sitko, Michael; Mayama, Satoshi; Kusakabe, Nobuyuki; Grady, Carol A.; McElwain, Michael W.

2015-01-01

We present new high-resolution (approximately 0.09) H-band imaging observations of the circumstellar disk around the T Tauri star SU Aur. Our observations with Subaru-HiCIAO have revealed the presence of scattered light as close as 0.15 (approximately 20 AU) to the star. Within our image, we identify bright emission associated with a disk with a minimum radius of approximately 90 AU, an inclination of approximately 35 deg from the plane of the sky, and an approximate PA of 15 deg for the major axis. We find a brightness asymmetry between the northern and southern sides of the disk due to a non-axisymmetric disk structure. We also identify a pair of asymmetric tail structures extending east and west from the disk. The western tail extends at least 2. 5 (350 AU) from the star, and is probably associated with a reflection nebula previously observed at optical and near-IR wavelengths. The eastern tail extends at least 1 (140 AU) at the present signal-to-noise. These tails are likely due to an encounter with an unseen brown dwarf, but our results do not exclude the explanation that these tails are outflow cavities or jets.

An energy-filtering device coupled to a quadrupole mass spectrometer for soft-landing molecular ions on surfaces with controlled energy

Energy Technology Data Exchange (ETDEWEB)

Bodin, A.; Laloo, R.; Abeilhou, P.; Guiraud, L.; Gauthier, S.; Martrou, D. [Nanosciences Group, CEMES, CNRS UPR 8011 and University Toulouse III - Paul Sabatier, 29 rue Jeanne Marvig, BP94347, F-31055 Toulouse Cedex 4 (France)

2013-09-15

We have developed an energy-filtering device coupled to a quadrupole mass spectrometer to deposit ionized molecules on surfaces with controlled energy in ultra high vacuum environment. Extensive numerical simulations as well as direct measurements show that the ion beam flying out of a quadrupole exhibits a high-energy tail decreasing slowly up to several hundred eV. This energy distribution renders impossible any direct soft-landing deposition of molecular ions. To remove this high-energy tail by energy filtering, a 127° electrostatic sector and a specific triplet lenses were designed and added after the last quadrupole of a triple quadrupole mass spectrometer. The results obtained with this energy-filtering device show clearly the elimination of the high-energy tail. The ion beam that impinges on the sample surface satisfies now the soft-landing criterion for molecular ions, opening new research opportunities in the numerous scientific domains involving charges adsorbed on insulating surfaces.

Bioleaching of arsenic from highly contaminated mine tailings using Acidithiobacillus thiooxidans.

Science.gov (United States)

Lee, Eunseong; Han, Yosep; Park, Jeonghyun; Hong, Jeongsik; Silva, Rene A; Kim, Seungkon; Kim, Hyunjung

2015-01-01

The behavior of arsenic (As) bioleaching from mine tailings containing high amount of As (ca. 34,000 mg/kg) was investigated using Acidithiobacillus thiooxidans to get an insight on the optimal conditions that would be applied to practical heap and/or tank bioleaching tests. Initial pH (1.8-2.2), temperature (25-40 °C), and solid concentration (0.5-4.0%) were employed as experimental parameters. Complementary characterization experiments (e.g., XRD, SEM-EDS, electrophoretic mobility, cell density, and sulfate production) were also carried out to better understand the mechanism of As bioleaching. The results showed that final As leaching efficiency was similar regardless of initial pH. However, greater initial As leaching rate was observed at initial pH 1.8 than other conditions, which could be attributed to greater initial cell attachment to mine tailings. Unlike the trend observed when varying the initial pH, the final As leaching efficiency varied with the changes in temperature and solid concentration. Specifically, As leaching efficiency tended to decrease with increasing temperature due to the decrease in the bacterial growth rate at higher temperature. Meanwhile, As leaching efficiency tended to increase with decreasing solid concentration. The results for jarosite contents in mine tailings residue after bioleaching revealed that much greater amount of the jarosite was formed during the bioleaching reaction at higher solid concentration, suggesting that the coverage of the surface of the mine tailings by jarosite and/or the co-precipitation of the leached As with jarosite could be a dominant factor reducing As leaching efficiency. Copyright © 2014 Elsevier Ltd. All rights reserved.

10 CFR 40.2a - Coverage of inactive tailings sites.

Science.gov (United States)

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Coverage of inactive tailings sites. 40.2a Section 40.2a... Coverage of inactive tailings sites. (a) Prior to the completion of the remedial action, the Commission..., if the site is covered by the remedial action program of title I of the Uranium Mill Tailings...

Uranium mill tailings conditioning technology

International Nuclear Information System (INIS)

Dreesen, D.R.; Cokal, E.J.; Wangen, L.E.; Williams, J.M.; O'Brien, P.D.; Thode, E.F.

1982-01-01

Conditioning of uranium mill tailings involves the physicochemical alteration of tailings to remove or immobilize mobile radionuclides and toxic trace elements before disposal in a repository. The principal immobilization approach under investigation is sintering tailings at high temperatures (1100-1200 deg. C) to radically alter the structure of tailings. This thermal stabilization at 1200 deg. C reduced radon emanation power for tailings sands by factors of 20 to 200 and for tailings fines by factors of 300 to 1100. Substantial reductions in the leachability of most contaminants have been found for thermally conditioned tailings. Obvious mineral transformations occur, including an increase in amorphous material, the conversion of gypsum to anhydrite and its subsequent decomposition, the disappearance of clay minerals, and some decrease in quartz content. A conceptual thermal stabilization process has been developed wherein obsolete coal-fired rotary cement kilns perform the sintering. An economic analysis of this conceptual process has shown that thermal stabilization can be competitive at certain tailings sites with other remedial actions requiring the excavation, transportation, and burial of tailings in a repository. An analysis of the long-term radiological hazard posed by untreated tailings and by tailings conditioned by radionuclide removal has illustrated the necessity of extracting both 226 Ra and 230 Th to achieve long-term hazard reductions. Sulphuric acid extraction of residual mineral values and important radionuclides from tailings has been investigated. Concentrated H 2 SO 4 can extract up to 80% of the 226 Ra, 70% of the Ba, and 90% of the 230 Th from tailings in a single stage extraction. An economic analysis of a sulphuric acid leach process was made to determine whether the value of minerals recovered from tailings would offset the leaching cost. For one relatively mineral-rich tailings pile, the U and V values would more than pay for the

Tail index and quantile estimation with very high frequency data

NARCIS (Netherlands)

J. Daníelsson (Jón); C.G. de Vries (Casper)

1997-01-01

textabstractA precise estimation of the tail shape of forex returns is of critical importance for proper risk assessment. We improve upon the efficiency of conventional estimators that rely on a first order expansion of the tail shape, by using the second order expansion. Here we advocate a moments

Genome-wide detection of CNVs in Chinese indigenous sheep with different types of tails using ovine high-density 600K SNP arrays

OpenAIRE

Zhu, Caiye; Fan, Hongying; Yuan, Zehu; Hu, Shijin; Ma, Xiaomeng; Xuan, Junli; Wang, Hongwei; Zhang, Li; Wei, Caihong; Zhang, Qin; Zhao, Fuping; Du, Lixin

2016-01-01

Chinese indigenous sheep can be classified into three types based on tail morphology: fat-tailed, fat-rumped, and thin-tailed sheep, of which the typical breeds are large-tailed Han sheep, Altay sheep, and Tibetan sheep, respectively. To unravel the genetic mechanisms underlying the phenotypic differences among Chinese indigenous sheep with tails of three different types, we used ovine high-density 600K SNP arrays to detect genome-wide copy number variation (CNV). In large-tailed Han sheep, A...

Taming the tailings : dead ducks notwithstanding, extensive research is underway to deal with oilsands tailings in a more efficient manner

Energy Technology Data Exchange (ETDEWEB)

Collison, M.

2008-09-15

Research is now being conducted to reduce the environmental impacts of oil sands tailing ponds. Alberta's oil sands region contains an estimated 60 km{sup 2} of tailings ponds, which serve as holding basins for recycled water as well as collection sites for materials used in reclamation activities. The ponds contain residual bitumen, production chemicals, and minerals. While some of the water in the ponds can be re-used, mature fine tailings must be contained behind dikes. Every barrel of bitumen produced by the industry results in the creation of 1.5 barrels of mature fine tailings. Natural Resources Canada's CANMET Energy Technology Centre is currently conducting a research program with the University of Alberta to reduce the amounts of tailings produced by the industry. Options for dry stackable tailings are being explored, as well as methods of using the tailings to enhance various oil sands processes. It is hoped that the dry, stackable tailings can be used to help reclaim and rebuild Boreal regions impacted by the oil sands industry. The program is gaining interest due to concerns that leakages from the tailings ponds may pollute aquifers and rivers in a region noted for its water shortages. Research teams are also investigating the use of flocculants to create heavy non-segregated tailings. Researchers are also examining methods of recovering hydrocarbons, titanium, and zircon from the tailings. 3 figs.

Comparative study on effects of four energy plants growth on chemical fractions of heavy metals and activity of soil enzymes in copper mine tailings.

Science.gov (United States)

Zhang, Jie; Yang, Shiyong; Yang, Hongfei; Huang, Yongjie; Zheng, Liming; Yuan, Jing; Zhou, Shoubiao

2018-05-12

Four gramineous energy plants, Miscanthus sacchariflorus, M. floridulus, Phragmites australis, and Arundo donax were grown on copper tailings in the field for four years. Their phytoremediation potential was examined in terms of their effects on the fractions of heavy metals and soil enzyme activities. Results showed that plantation of these four gramineous plants has improved the proportion of organic material (OM)-binding fraction of heavy metals in copper tailings as a whole, and reduced the proportion of exchangeable and residual fractions. In particular, M. sacchariflorus growth improved significantly the proportion of the OM-binding fractions of Cu (1.73 times), Cd (1.71 times), Zn (1.18 times), and Pb (3.14 times) (P tailings to some extent. In particular, the activity of soil phosphatase and urease in planted tailings differed significantly from that of control (P tailings.

Lifshitz Tails for the Interband Light Absorption Coefficient

Indian Academy of Sciences (India)

In this paper we consider the interband light absorption coefficient (ILAC) for various models. We show that at the lower and upper edges of the spectrum the Lifshitz tails behaviour of the density of states implies similar behaviour for the ILAC at appropriate energies. The Lifshitz tails property is also exhibited at some points ...

Geochemical and mineralogical characterization of a neutral, low-sulfide/high-carbonate tailings impoundment, Markušovce, eastern Slovakia.

Science.gov (United States)

Hiller, Edgar; Petrák, Marián; Tóth, Roman; Lalinská-Voleková, Bronislava; Jurkovič, L'ubomír; Kučerová, Gabriela; Radková, Anežka; Sottník, Peter; Vozár, Jaroslav

2013-11-01

mineral assemblage and their occurrence follows the order: chalcopyrite > pyrite > tetrahedrite>arsenopyrite. The mineralogical composition of the tailings corresponds well to the primary mineralization mined. The neutralization capacity of the tailings is high, as confirmed by the values of neutralization potential to acid generation potential ratio, ranging from 6.7 to 63.9, and neutral to slightly alkaline pH of the tailings (paste pH 7.16-8.12) and the waters (pH 7.00-8.52). This is explained by abundant occurrence of carbonate minerals in the tailings, which readily neutralize the acidity generated by sulfide oxidation. The total solid-phase concentrations of metal(loid)s decrease as Cu>Sb>Hg>As and reflect the proportions of sulfides present in the tailings. Sulfide oxidation generally extends to a depth of 2 m. μ-XRD and EMPA were used to study secondary products developed on the surface of sulfide minerals and within the tailings. The main secondary minerals identified are goethite and X-ray amorphous Fe oxyhydroxides and their occurrence decreases with increasing tailings depth. Secondary Fe phases are found as mineral coatings or individual grains and retain relatively high amounts of metal(loid)s (up to 57.6 wt% Cu, 1.60 wt% Hg, 23.8 wt% As, and 2.37 wt% Sb). Based on batch leaching tests and lysimeter results, the mobility of potentially toxic elements in the tailings is low. The limited mobility of metals and metalloids is due to their retention by Fe oxyhydroxides and low solubilities of metal(loid)-bearing sulfides. The observations are consistent with PHREEQC calculations, which predict the precipitation of Fe oxyhydroxides as the main solubility-controlling mineral phases for As, Cu, Hg, and Sb. Waters discharging from tailings impoundment are characterized by a neutral to slightly alkaline pH (7.52-7.96) and low concentrations of dissolved metal(loid)s (tailings impoundment.

Predicting arsenic concentrations in porewaters of buried uranium mill tailings

Energy Technology Data Exchange (ETDEWEB)

Langmuir, D.; Mahoney, J.; MacDonald, A.; Rowson, J.

1999-10-01

The proposed JEB Tailings Management Facility (TMF) to be emplaced below the groundwater table in northern Saskatchewan, Canada, will contain uranium mill tailings from McClean Lake, Midwest and Cigar Lake ore bodies, which are high in arsenic (up to 10%) and nickel (up to 5%). A serious concern is the possibility that high arsenic and nickel concentrations may be released from the buried tailings, contaminating adjacent groundwaters and a nearby lake. Laboratory tests and geochemical modeling were performed to examine ways to reduce the arsenic and nickel concentrations in TMF porewaters so as to minimize such contamination from tailings buried for 50 years and longer. The tests were designed to mimic conditions in the mill neutralization circuit (3 hr tests at 25 C), and in the TMF after burial (5--49 day aging tests). The aging tests were run at 50, 25 and 4 C (the temperature in the TMF). In order to optimize the removal of arsenic by adsorption and precipitation, ferric sulfate was added to tailings raffinates having Fe/As ratios of less than 3--5. The acid raffinates were then neutralized by addition of slaked lime to nominal pH values of 7, 8, or 9. Analysis and modeling of the test results showed that with slaked lime addition to acid tailings raffinates, relatively amorphous scorodite (ferric arsenate) precipitates near pH 1, and is the dominant form of arsenate in slake limed tailings solids except those high in Ni and As and low in Fe, in which cabrerite-annabergite (Ni, Mg, Fe(II) arsenate) may also precipitate near pH 5--6. In addition to the arsenate precipitates, smaller amounts of arsenate are also adsorbed onto tailings solids. The aging tests showed that after burial of the tailings, arsenic concentrations may increase with time from the breakdown of the arsenate phases (chiefly scorodite). However, the tests indicate that the rate of change decreases and approaches zero after 72 hrs at 25 C, and may equal zero at all times in the TMF at 4 C

Thermal stabilization of uranium mill tailings

International Nuclear Information System (INIS)

Dreesen, D.R.; Williams, J.M.; Cokal, E.J.

1981-01-01

The sintering of tailings at high temperatures (1200 0 C) has shown promise as a conditioning approach that greatly reduces the 222 Rn emanation of uranium mill tailings. The structure of thermally stabilized tailings has been appreciably altered producing a material that will have minimal management requirements and will be applicable to on-site processing and disposal. The mineralogy of untreated tailings is presented to define the structure of the original materials. Quartz predominates in most tailings samples; however, appreciable quantities of gypsum, clay, illite, or albites are found in some tailings. Samples from the Durango and Shiprock sites have plagioclase-type aluminosilicates and non-aluminum silicates as major components. The iron-rich vanadium tailings from the Salt Lake City site contain appreciable quantities of α-hematite and chloroapatite. The reduction in radon emanation power and changes in mineralogy as a function of sintering temperature are presented

Analysis of pp and pp-bar elastic scattering amplitudes at high energies

Energy Technology Data Exchange (ETDEWEB)

Ferreira, E.; Kodama, T.; Kohara, A.K. [Universidade Federal do Rio de Janeiro (IF/UFRJ), RJ (Brazil). Inst. de Fisica

2012-07-01

Full text: A careful analysis of high energies elastic scattering data at 7 TeV for pp, 1800 - 1950 GeV for pp-bar and 540 -541 GeV for pp-bar in terms of its amplitudes has been performed as natural extension of previous analysis for lower energies. The disentanglement of the real and imaginary parts is written consistently with constraints from dispersion relations for amplitudes and for slopes, and also satisfying the universal asymptotic behavior for large |t| values due to the three gluon Exchange process. Values for the imaginary and real slopes and for the total cross section at 7 TeV, 1800-1950 GeV and 540-541 GeV are presented, and the shape of the differential cross section at 14 TeV, with a dip/bump structure more marked and at a smaller values of |t| is predicted. It is predicted that future measurements at large |t| will be connected smoothly with the perturbative tail observed in the interval 5.5 to 14.2 GeV{sup 2} at lower energies and that a marked dip would be observed in pp-bar scattering near this tail range. It is stressed for the consistent description of elastic pp and pp-bar data and pointed out the importance of the future measurements in the Coulomb interference range and in the transition range to the perturbative tail where the perturbative and non-perturbative effects appears together. (author)

Estimation of Jump Tails

DEFF Research Database (Denmark)

Bollerslev, Tim; Todorov, Victor

We propose a new and flexible non-parametric framework for estimating the jump tails of Itô semimartingale processes. The approach is based on a relatively simple-to-implement set of estimating equations associated with the compensator for the jump measure, or its "intensity", that only utilizes...... the weak assumption of regular variation in the jump tails, along with in-fill asymptotic arguments for uniquely identifying the "large" jumps from the data. The estimation allows for very general dynamic dependencies in the jump tails, and does not restrict the continuous part of the process...... and the temporal variation in the stochastic volatility. On implementing the new estimation procedure with actual high-frequency data for the S&P 500 aggregate market portfolio, we find strong evidence for richer and more complex dynamic dependencies in the jump tails than hitherto entertained in the literature....

Overview by Pioneer observations of the distant geomagnetic tail

Energy Technology Data Exchange (ETDEWEB)

Villante, U [L' Aquila Univ. (Italy). Istituto de Astrofisica

1977-03-01

Pioneer 7 and Pioneer 8 spacecraft provided the only direct observations of the geomagnetic tail at geocentric distances as large as 1000 Rsub(e) and 500 Rsub(e) respectively. The presence of a low density plasma flow in the region of expected tail and the intermittent and short duration character of the tail encounters suggested in the past a distant tail structure remarkably different from its near-earth and cislunar shape. However the recent discovery of the plasma mantle allows interpretation of the Pioneer observations in terms of a distant tail that possibly is still preserving most of its near-earth characteristics. In particular, the region of tail encounters and the magnitude and direction of the observed magnetic field might be consistent with a cylindrical tail with a modestly increased cross-section. Neutral sheet observations also appear to be consistent with the most recent bidimensional tail models. Finally, as in the cislunar region, the double peaked proton energy spectra can be interpreted in terms of a partial intermingling of plasma sheet and plasma mantle populations.

Metabolic substrate use and the turnover of endogenous energy reserves in broad-tailed hummingbirds (Selasphorus platycercus).

Science.gov (United States)

Carleton, Scott A; Bakken, Bradley Hartman; Del Rio, Carlos Martínez

2006-07-01

We fed broad-tailed hummingbirds (Selasphorus platycercus) diets of contrasting carbon isotope composition and measured changes in the delta(13)C of expired breath through time. By measuring the delta(13)C in the breath of fed and fasted birds we were able to quantify the fraction of metabolism fueled by assimilated sugars and endogenous energy reserves. These measurements also allowed us to estimate the fractional turnover of carbon in the hummingbirds' energy reserves. When hummingbirds were feeding, they fueled their metabolism largely ( approximately 90%) with assimilated sugars. The rate of carbon isotope incorporation into the energy reserves of hummingbirds was higher when birds were gaining as opposed to losing body mass. The average residence time of a carbon atom in the hummingbirds' energy reserves ranged from 1 to 2 days.

The radiological impacts of uranium mill tailings - a review with special emphasis on the tailings at Ranstad in Sweden

International Nuclear Information System (INIS)

Snihs, J.O.; Agnedal, P.O.

1978-07-01

The environmental impact of uranium mill tailings can be expressed in collective dose commitment and corresponding detriment per MWsub(e).Y energy produced by the uranium which corresponds to the amount of waste of interest. The methods of dose commitment calculations are discussed and it is suggested for the purpose of estimation of the detriment to limit the commitment to 10,000 years. The external radiation from the tailings is easily reduced by covering but in case of a future settlement on the tailings the collective dose commitment will be some hundreds to thousands of manrad/MWsub(e).Y depending on the quality of the uranium ore. The dispersion of dust from uncovered tailings is mainly a local problem and the collective dose commitment for critical tissues in the lung will be less than a manrad/MWsub(e).Y. In the long run the cover may be lost and the resultant collective dose commitment for the critical tissues in the lung will be a few tens of manrad/MWsub(e).Y depending on the quality of the tailings. The effects of global dispersion of the material in the tailings are also discussed

The hydrogeochemistry of four inactive tailings impoundments: Perspectives on tailings pore-water evolution

International Nuclear Information System (INIS)

Blowes, D.W.; Cherry, J.A.; Reardon, E.J.

1987-01-01

Extensive hydrogeochemical investigations are currently underway at three inactive tailings impoundments in Canada. These programs include detailed measurements of pore-water and gas-phase geochemistry through the vadose zone and the groundwater zone. An extensive piezometer network has been installed at each location to monitor the groundwater flow regime. All of the impoundments studied have been inactive for 15 to 25 years, sufficient time for extensive tailings pore-water evolution. The study areas include a very high-sulfide impoundment, a low-sulfide, high-carbonate impoundment, a low-sulfide, very low-carbonate impoundment, and a moderately high-sulfide impoundment. The pore water at each of the sites has evolved in a distinctly different and characteristic manner, representing broad styles of tailings pore-water evolution. At the high sulfide impoundment the oxidation of sulfide minerals has resulted in low pH, high redox potential conditions, with Fe 2+ concentrations in excess of 60,000 mg/L. At a depth of about 40 cm a 10 cm thick layer of ferrous and calcium sulfate minerals has precipitated. This hardpan layer limits the downward movement of O 2 and infiltrating pore waters. As a result, the pore water chemistry, both above and below the hardpan layer, has remained relatively unchanged over the past 10 years. The low-sulfide, high-carbonate tailings are sufficiently well buffered that no low pH conditions are present. The high pH conditions limit the concentrations of the metals released by sulfide mineral oxidation to levels that are two or three orders of magnitude less than is observed at the high-sulfide site. Pore waters at the low-sulfide, low-carbonate site were sampled by other researchers from the University of Waterloo

TIDAL TAILS OF MINOR MERGERS. II. COMPARING STAR FORMATION IN THE TIDAL TAILS OF NGC 2782

Energy Technology Data Exchange (ETDEWEB)

Knierman, Karen A.; Scowen, Paul; Veach, Todd; Groppi, Christopher [School of Earth and Space Exploration, Arizona State University, 550 E. Tyler Mall, Room PSF-686 (P.O. Box 871404), Tempe, AZ 85287-1404 (United States); Mullan, Brendan; Charlton, Jane [Department of Astronomy and Astrophysics, Penn State University, 525 Davey Lab, University Park, PA (United States); Konstantopoulos, Iraklis [Australian Astronomical Observatory, P.O. Box 915, North Ryde NSW 1670 (Australia); Knezek, Patricia M., E-mail: karen.knierman@asu.edu, E-mail: paul.scowen@asu.edu, E-mail: tveach@asu.edu, E-mail: cgroppi@asu.edu, E-mail: mullan@astro.psu.edu, E-mail: iraklis@aao.gov.au, E-mail: pknezek@noao.edu [WIYN Consortium, Inc., 950 N. Cherry Avenue, Tucson, AZ 85719 (United States)

2013-09-10

The peculiar spiral NGC 2782 is the result of a minor merger with a mass ratio {approx}4: 1 occurring {approx}200 Myr ago. This merger produced a molecular and H I-rich, optically bright eastern tail and an H I-rich, optically faint western tail. Non-detection of CO in the western tail by Braine et al. suggested that star formation had not yet begun. However, deep UBVR and H{alpha} narrowband images show evidence of recent star formation in the western tail, though it lacks massive star clusters and cluster complexes. Using Herschel PACS spectroscopy, we discover 158 {mu}m [C II] emission at the location of the three most luminous H{alpha} sources in the eastern tail, but not at the location of the even brighter H{alpha} source in the western tail. The western tail is found to have a normal star formation efficiency (SFE), but the eastern tail has a low SFE. The lack of CO and [C II] emission suggests that the western tail H II region may have a low carbon abundance and be undergoing its first star formation. The western tail is more efficient at forming stars, but lacks massive clusters. We propose that the low SFE in the eastern tail may be due to its formation as a splash region where gas heating is important even though it has sufficient molecular and neutral gas to make massive star clusters. The western tail, which has lower gas surface density and does not form high-mass star clusters, is a tidally formed region where gravitational compression likely enhances star formation.

TIDAL TAILS OF MINOR MERGERS. II. COMPARING STAR FORMATION IN THE TIDAL TAILS OF NGC 2782

International Nuclear Information System (INIS)

Knierman, Karen A.; Scowen, Paul; Veach, Todd; Groppi, Christopher; Mullan, Brendan; Charlton, Jane; Konstantopoulos, Iraklis; Knezek, Patricia M.

2013-01-01

The peculiar spiral NGC 2782 is the result of a minor merger with a mass ratio ∼4: 1 occurring ∼200 Myr ago. This merger produced a molecular and H I-rich, optically bright eastern tail and an H I-rich, optically faint western tail. Non-detection of CO in the western tail by Braine et al. suggested that star formation had not yet begun. However, deep UBVR and Hα narrowband images show evidence of recent star formation in the western tail, though it lacks massive star clusters and cluster complexes. Using Herschel PACS spectroscopy, we discover 158 μm [C II] emission at the location of the three most luminous Hα sources in the eastern tail, but not at the location of the even brighter Hα source in the western tail. The western tail is found to have a normal star formation efficiency (SFE), but the eastern tail has a low SFE. The lack of CO and [C II] emission suggests that the western tail H II region may have a low carbon abundance and be undergoing its first star formation. The western tail is more efficient at forming stars, but lacks massive clusters. We propose that the low SFE in the eastern tail may be due to its formation as a splash region where gas heating is important even though it has sufficient molecular and neutral gas to make massive star clusters. The western tail, which has lower gas surface density and does not form high-mass star clusters, is a tidally formed region where gravitational compression likely enhances star formation

Assessment of the underground disposal of tailings

Energy Technology Data Exchange (ETDEWEB)

Hutt, N M [Morwijk Enterprises Ltd., (Canada); Morin, K A [Normar Enterprises, (Canada)

1995-06-01

The Atomic Energy Control Board (AECB) of Canada is facing the issue of long-term disposal of uranium tailings. One option that has not been examined in sufficient detail for the AECB is the retrieval of tailings from surface impoundments and subsequent placement of those tailings in underground workings of mines. This report is structured like a catalogue of facts and information, with each paragraph presenting some concept, concern, theory, or case study involving the retrieval or placement of tailings. All relevant information, findings, interpretations, conclusions, and recommendations gathered during the course of this study are included. The Table of Contents illustrates the striking number of relevant topics and acts like a flowchart or checklist to ensure that an underground-disposal submission by a mining company has addressed relevant topics. This report explains in detail the implications of disturbing surface-impounded tailings for the purpose of placing only some of the volume underground. The cumulative environmental, safety, and monetary liabilities of such a partial scheme can be discouraging in some cases. (author). 244 refs., 47 tabs., 17 figs.

Assessment of the underground disposal of tailings

International Nuclear Information System (INIS)

Hutt, N.M.; Morin, K.A.

1995-06-01

The Atomic Energy Control Board (AECB) of Canada is facing the issue of long-term disposal of uranium tailings. One option that has not been examined in sufficient detail for the AECB is the retrieval of tailings from surface impoundments and subsequent placement of those tailings in underground workings of mines. This report is structured like a catalogue of facts and information, with each paragraph presenting some concept, concern, theory, or case study involving the retrieval or placement of tailings. All relevant information, findings, interpretations, conclusions, and recommendations gathered during the course of this study are included. The Table of Contents illustrates the striking number of relevant topics and acts like a flowchart or checklist to ensure that an underground-disposal submission by a mining company has addressed relevant topics. This report explains in detail the implications of disturbing surface-impounded tailings for the purpose of placing only some of the volume underground. The cumulative environmental, safety, and monetary liabilities of such a partial scheme can be discouraging in some cases. (author). 244 refs., 47 tabs., 17 figs

TCP (truncated compound Poisson) process for multiplicity distributions in high energy collisions

International Nuclear Information System (INIS)

Srivastave, P.P.

1990-01-01

On using the Poisson distribution truncated at zero for intermediate cluster decay in a compound Poisson process, the authors obtain TCP distribution which describes quite well the multiplicity distributions in high energy collisions. A detailed comparison is made between TCP and NB for UA5 data. The reduced moments up to the fifth agree very well with the observed ones. The TCP curves are narrower than NB at high multiplicity tail, look narrower at very high energy and develop shoulders and oscillations which become increasingly pronounced as the energy grows. At lower energies the distributions, of the data for fixed intervals of rapidity for UA5 data and for the data (at low energy) for e + e - annihilation and pion-proton, proton-proton and muon-proton scattering. A discussion of compound Poisson distribution, expression of reduced moments and Poisson transforms are also given. The TCP curves and curves of the reduced moments for different values of the parameters are also presented

Electron energization in the geomagnetic tail current sheet

International Nuclear Information System (INIS)

Lyons, L.R.

1984-01-01

Electron motion in the distant tail current sheet is evaluated and found to violate the guiding center approximation at energies > or approx. =100 eV. Most electrons within the energy range approx.10 -1 -10 2 keV that enter the current sheet become trapped within the magnetic field reversal region. These electrons then convect earthward and gain energy from the cross-tail electric field. If the energy spectrum of electrons entering the current sheet is similar to that of electrons from the boundary layer surrounding the magnetotail, the energy gain from the electric field produces electron energy spectra comparable to those observed in the earth's plasma sheet. Thus current sheet interactions can be a significant source of particles and energy for plasma sheet electrons as well as for plasma sheet ions. A small fraction of electrons within the current sheet has its pitch angles scattered so as to be ejected from the current sheet within the atmospheric loss cone. These electrons can account for the electron precipitation near the high-latitude boundary of energetic electrons, which is approximately isotropic in pitch angle up to at least several hundred keV. Current sheet interaction should cause approximately isotropic auroral precipitation up to several hundred keV energies, which extends to significantly lower latitudes for ions than for electrons in agreement with low-altitude satellite observations. Electron precipitation associated with diffuse aurora generally has a transition at 1-10 keV to anisotropic pitch angle distributions. Such electron precipitation cannot be explained by current sheet interactions, but it can be explained by pitch angle diffusion driven by plasma turbulence

Telling tails: selective pressures acting on investment in lizard tails.

Science.gov (United States)

Fleming, Patricia A; Valentine, Leonie E; Bateman, Philip W

2013-01-01

Caudal autotomy is a common defense mechanism in lizards, where the animal may lose part or all of its tail to escape entrapment. Lizards show an immense variety in the degree of investment in a tail (i.e., length) across species, with tails of some species up to three or four times body length (snout-vent length [SVL]). Additionally, body size and form also vary dramatically, including variation in leg development and robustness and length of the body and tail. Autotomy is therefore likely to have fundamentally different effects on the overall body form and function in different species, which may be reflected directly in the incidence of lost/regenerating tails within populations or, over a longer period, in terms of relative tail length for different species. We recorded data (literature, museum specimens, field data) for relative tail length (n=350 species) and the incidence of lost/regenerating tails (n=246 species). We compared these (taking phylogeny into account) with intrinsic factors that have been proposed to influence selective pressures acting on caudal autotomy, including body form (robustness, body length, leg development, and tail specialization) and ecology (foraging behavior, physical and temporal niches), in an attempt to identify patterns that might reflect adaptive responses to these different factors. More gracile species have relatively longer tails (all 350 spp., P lost/regenerating tails for nocturnal lizards (all 246 spp., P pressure.

Piezoelectric energy harvesting from colored fat-tailed fluctuations: An electronic analogy

Directory of Open Access Journals (Sweden)

J. I. Peña Rosselló

2015-09-01

Full Text Available Aiming to optimize piezoelectric energy harvesting from strongly col-ored fat-tailed fluctuations, we have recently studied the performance ofa monostable inertial device under a noise whose statistics depends on aparameter q (bounded for q 1.We have studied the interplay between the potential shape (interpolatingbetween square-well and harmonic-like behaviors and the noise’s statis-tics and spectrum, and showed that its output power grows as q increasesabove 1. We now report a real experiment on an electronic analog of theproposed system, which sheds light on its operating principle. Received: 20 Novembre 2014, Accepted: 7 September 2015; Edited by: C. A. Condat, G. J. Sibona; DOI:http://dx.doi.org/10.4279/PIP.070014 Cite as: J I Peña Rosselló, R Deza, J . Deza, H S Wio, Papers in Physics 7, 070014 (2015

Geophysical applications for oil sand mine tailings management

Energy Technology Data Exchange (ETDEWEB)

Parker, D.; Bauman, P. [WorleyParsons, Calgary, AB (Canada)

2009-07-01

Geophysical techniques are applied throughout a mine's life cycle to facilitate siting, constructing and monitoring of tailings dumps and ponds. This presentation described 3 case studies from the Athabasca region in northeast Alberta that demonstrated some of the concerns associated with oil sand mine tailings, and the information that geophysical surveys can provide. The objectives of these studies were to determine the lateral and depth extents of elevated conductivities of soil and groundwater that have high salt concentration from the tailings sand pore fluid. Due to high chloride concentrations within the tailings material, salt within the root zone may affect vegetation. A terrain conductivity survey was designed to map the lateral extents of salinity impact, while an electrical resistivity tomography (ERT) survey was used to delineate the tailings sand leachate at depth. The proper management of oil sand tailings facilities is vital to the life cycle of a mine. It was concluded that geophysical techniques can be instrumental in managing several engineering and environmental challenges, from Pleistocene channel mapping, to tailings pond settling characteristics, to reclaiming tailings sands. 1 ref., 7 figs.

Hg in snow cover and snowmelt waters in high-sulfide tailing regions (Ursk tailing dump site, Kemerovo region, Russia).

Science.gov (United States)

Gustaytis, M A; Myagkaya, I N; Chumbaev, A S

2018-07-01

Gold-bearing polymetallic Cu-Zn deposits of sulphur-pyrite ores were discovered in the Novo-Ursk region in the 1930s. The average content of mercury (Hg) was approximately 120 μg/g at the time. A comprehensive study of Hg distribution in waste of metal ore enrichment industry was carried out in the cold season on the tailing dump site and in adjacent areas. Mercury concentration in among snow particulate, dissolved and colloid fractions was determined. The maximal Hg content in particulate fraction from the waste tailing site ranged 230-573 μg/g. Such indices as the frequency of aerosol dust deposition events per units of time and area, enrichment factor and the total load allowed to establish that the territory of the tailing waste dump site had a snow cover highly contaminated with dust deposited at a rate of 247-480 mg/(m 2 ∙day). Adjacent areas could be considered as area with low Hg contamination rate with average deposition rate of 30 mg/(m 2 ∙day). The elemental composition of the aerosol dust depositions was determined as well, which allowed to reveal the extent of enrichment waste dispersion throughout adjacent areas. The amount of Hg entering environment with snowmelt water discharge was estimated. As a result of snowmelting, in 2014 the nearest to the dump site hydrographic network got Hg as 7.1 g with colloids and as 5880 g as particles. The results obtained allowed to assess the degree of Hg contamination of areas under the impact of metal enrichment industry. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Sodium Tail of the Moon

Science.gov (United States)

Matta, M.; Smith, S.; Baumgardner, J.; Wilson, J.; Martinis, C.; Mendillo, M.

2009-01-01

During the few days centered about new Moon, the lunar surface is optically hidden from Earth-based observers. However, the Moon still offers an observable: an extended sodium tail. The lunar sodium tail is the escaping "hot" component of a coma-like exosphere of sodium generated by photon-stimulated desorption, solar wind sputtering and meteoroid impact. Neutral sodium atoms escaping lunar gravity experience solar radiation pressure that drives them into the anti-solar direction forming a comet-like tail. During new Moon time, the geometry of the Sun, Moon and Earth is such that the anti-sunward sodium flux is perturbed by the terrestrial gravitational field resulting in its focusing into a dense core that extends beyond the Earth. An all-sky camera situated at the El Leoncito Observatory (CASLEO) in Argentina has been successfully imaging this tail through a sodium filter at each lunation since April 2006. This paper reports on the results of the brightness of the lunar sodium tail spanning 31 lunations between April 2006 and September 2008. Brightness variability trends are compared with both sporadic and shower meteor activity, solar wind proton energy flux and solar near ultra violet (NUV) patterns for possible correlations. Results suggest minimal variability in the brightness of the observed lunar sodium tail, generally uncorrelated with any single source, yet consistent with a multi-year period of minimal solar activity and non-intense meteoric fluxes.

Tail position affects the body temperature of rats during cold exposure in a low-energy state.

Science.gov (United States)

Uchida, Yuki; Tokizawa, Ken; Nakamura, Mayumi; Lin, Cheng-Hsien; Nagashima, Kei

2012-02-01

Rats place their tails underneath their body trunks when cold (tail-hiding behavior). The aim of the present study was to determine whether this behavior is necessary to maintain body temperature. Male Wistar rats were divided into 'fed' and '42-h fasting' groups. A one-piece tail holder (8.4 cm in length) that prevented the tail-hiding behavior or a three-piece tail holder (2.8 cm in length) that allowed for the tail-hiding behavior was attached to the tails of the rats. The rats were exposed to 27°C for 180 min or to 20°C for 90 min followed by 15°C for 90 min with continuous body temperature and oxygen consumption measurements. Body temperature decreased by -1.0 ± 0.1°C at 15°C only in the rats that prevented tail-hiding behavior of the 42-h fasting group, and oxygen consumption increased at 15°C in all animals. Oxygen consumption was not different between the rats that prevented tail-hiding behavior and the rats that allowed the behavior in the fed and 42-h fasting groups under ambient conditions. These results show that the tail-hiding behavior is involved in thermoregulation in the cold in fasting rats.

Consolidation of tailings

International Nuclear Information System (INIS)

Nelson, J.D.; Wardwell, R.E.; Abt, S.R.; Staub, W.P.

1983-09-01

The integrity of cover systems placed on tailings impoundments will be affected by the potential for differential settlement of the tailings surface. Settlement of the sand fraction will occur relatively rapidly. The slimes will take longer time for consolidation and will produce greater settlement. This report reviews the phenomenon of consolidation for saturated and unsaturated tailings. The effect of load application by cover placement and the extent to which dewatering of tailings will cause consolidation are considered. In addition, the feasibility of inducing consolidation by alternative means and the potential applicability of these methods to tailings impoundments reclamation are discussed. Differential settlement of the tailings will cause tensile strain to be developed in covers. This strain could be large enough to cause cracking within a relatively brittle compacted clay. Dewatering of tailings by drainage can cause settlement even greater than that by placement of a cover material. Dewatering of the tailings would also increase the stability of the tailings surface, thereby enhancing reclamation operations. Consequently, in view of the enhanced surface stability and the fact that a portion of the differential settlement can be accomplished prior to cover placement, dewatering of tailings impoundments during operations may have benefical effects

Tail posture predicts tail biting outbreaks at pen level in weaner pigs

DEFF Research Database (Denmark)

Lahrmann, Helle Pelant; Hansen, Christian Fink; D'Eath, Rick

2018-01-01

posture and behaviour could be detected at pen level between upcoming tail biting pens (T-pens) and control pens (C-pens). The study included 2301 undocked weaner pigs in 74 pens (mean 31.1 pigs/pen; SD 1.5). Tails were scored three times weekly (wound freshness, wound severity and tail length) between 07......Detecting a tail biting outbreak early is essential to reduce the risk of pigs getting severe tail damage. A few previous studies suggest that tail posture and behavioural differences can predict an upcoming outbreak. The aim of the present study was therefore to investigate if differences in tail......:00 h-14:00 h from weaning until a tail biting outbreak. An outbreak (day 0) occurred when at least four pigs had a tail damage, regardless of wound freshness. On average 7.6 (SD 4.3) pigs had a damaged tail (scratches + wound) in T-pens on day 0. Tail posture and behaviour (activity, eating...

Energy and Pitch Distribution of Spontaneously-generated High-energy Bulk Ions in the RFP

Science.gov (United States)

Kim, Jungha; Anderson, Jay; Reusch, Joshua; Eilerman, Scott; Capecchi, William

2014-10-01

Magnetic reconnection events in the reversed field pinch (RFP) are known to heat bulk and impurity ions. Runaway due to a parallel electric field has recently been confirmed as an important acceleration mechanism for high energy test ions supplied by a neutral beam. This effect does not, however, explain the change in distribution of nearly Maxwellian bulk ions at a reconnection event. By operating MST near maximum current and low electron density, significant fusion neutron flux can be generated without neutral beam injection. The bulk ion distribution created in these plasmas is well-confined, non-Maxwellian, and can be measured by the Advanced Neutral Particle Analyzer (ANPA) placed at a radial or tangential porthole. Data show a high energy tail up to 25 keV with a relatively higher signal in the low energy channels (8-15 keV) at the radial port following a reconnection event. Analysis of the energy dependence of trapped orbits sampled by the ANPA at the radial view implies an abundance of lower energy particles in regions of higher neutral density. This mandates a careful deconvolution of the measured ANPA signal to compute the fast ion distribution. This work is supported by the US DOE and NSF.

Ecological aspects of microorganisms inhabiting uranium mill tailings

Science.gov (United States)

Miller, C.L.; Landa, E.R.; Updegraff, D.M.

1987-01-01

Numbers and types of microorganisms in uranium mill tailings were determined using culturing techniques. Arthrobacter were found to be the predominant microorganism inhabiting the sandy tailings, whereas Bacillus and fungi predominated in the slime tailings. Sulfate-reducing bacteria, capable of leaching radium, were isolated in low numbers from tailings samples but were isolated in significantly high numbers from topsoil in contact with the tailings. The results are placed in the context of the magnitude of uranium mill tailings in the United States, the hazards posed by the tailings, and how such hazards could be enhanced or diminished by microbial activities. Patterns in the composition of the microbial population are evaluated with respect to the ecological variables that influence microbial growth. ?? 1987 Springer-Verlag New York Inc.

Analysis of Heavy-Tailed Time Series

DEFF Research Database (Denmark)

Xie, Xiaolei

This thesis is about analysis of heavy-tailed time series. We discuss tail properties of real-world equity return series and investigate the possibility that a single tail index is shared by all return series of actively traded equities in a market. Conditions for this hypothesis to be true...... are identified. We study the eigenvalues and eigenvectors of sample covariance and sample auto-covariance matrices of multivariate heavy-tailed time series, and particularly for time series with very high dimensions. Asymptotic approximations of the eigenvalues and eigenvectors of such matrices are found...... and expressed in terms of the parameters of the dependence structure, among others. Furthermore, we study an importance sampling method for estimating rare-event probabilities of multivariate heavy-tailed time series generated by matrix recursion. We show that the proposed algorithm is efficient in the sense...

Vertical Tail Buffeting Alleviation Using Piezoelectric Actuators-Some Results of the Actively Controlled Response of Buffet-Affected Tails (ACROBAT) Program

Science.gov (United States)

Moses, Robert W.

1997-01-01

Buffet is an aeroelastic phenomenon associated with high performance aircraft especially those with twin vertical tails. In particular, for the F/A-18 aircraft at high angles of attack, vortices emanating from wing/fuselage leading edge extensions burst, immersing the vertical tails in their wake. The resulting buffet loads on the vertical tails are a concern from fatigue and inspection points of view. Recently, a 1/6-scale F-18 wind-tunnel model was tested in the Transonic Dynamics Tunnel at the NASA Langley Research Center as part of the Actively Controlled Response Of Buffet Affected Tails (ACROBAT) Program to assess the use of active controls in reducing vertical tail buffeting. The starboard vertical tail was equipped with an active rudder and the port vertical tail was equipped with piezoelectric actuators. The tunnel conditions were atmospheric air at Mach 0.10. By using single-input-single-output control laws at gains well below the physical limits of the actuators, the power spectral density of the root strains at the frequency of the first bending mode of the vertical tail was reduced by as much as 60 percent up to angles of attack of 37 degrees. Root mean square (RMS) values of root strain were reduced by as much as 19 percent. The results herein illustrate that buffet alleviation of vertical tails can be accomplished using simple active control of the rudder or piezoelectric actuators. In fact, as demonstrated herein, a fixed gain single input single output control law that commands piezoelectric actuators may be active throughout the high angle-of-attack maneuver without requiring any changes during the maneuver. Future tests are mentioned for accentuating the international interest in this area of research.

Tailings management best practice: a case study of the McClean Lake JEB Tailings Management Facility

International Nuclear Information System (INIS)

Tremblay, M.A.J.; Rowson, J.

2005-01-01

design of the TMF itself relies on the high permeability sandstone unit to provide a preferential flow path for groundwater around the low permeability tailings mass. This provides a passive means of minimizing the long-term release of constituents from the decommissioned facility to the environment. A comprehensive tailings optimization and validation program was developed to reduce uncertainties related to the performance of the tailings management facility associated with the chemical and physical properties of tailings. This paper will describe the JEB tailings management facility and provide a summary of the findings of this research program. (author)

An energetic perspective on tissue regeneration: The costs of tail autotomy in growing geckos.

Science.gov (United States)

Starostová, Zuzana; Gvoždík, Lumír; Kratochvíl, Lukáš

2017-04-01

Tail autotomy is a crucial antipredatory lizard response, which greatly increases individual survival, but at the same time also compromises locomotor performance, sacrifices energy stores and induces a higher burden due to the ensuing response of regenerating the lost body part. The potential costs of tail autotomy include shifts in energy allocation and metabolic rates, especially in juveniles, which invest their energy primarily in somatic growth. We compared the metabolic rates and followed the growth of juvenile males with and without regenerating tails in the Madagascar ground gecko (Paroedura picta), a nocturnal ground-dwelling lizard. Geckos with intact tails and those that were regrowing them grew in snout-vent-length at similar rates for 22weeks after autotomy. Tail regeneration had a negligible influence on body mass-corrected metabolic rate measured at regular intervals throughout the regenerative process. We conclude that fast-growing juveniles under the conditions of unrestricted food can largely compensate for costs of tail loss and regeneration in their somatic growth without a significant impact on the total individual body mass-corrected metabolic rate. Copyright © 2017 Elsevier Inc. All rights reserved.

The radiological impacts of uranium mill tailings - A review with special emphasis on the tailings at Ranstad in Sweden

International Nuclear Information System (INIS)

Snihs, J.O.

1978-01-01

The environmental impact of uranium mill talings can be expressed in collective dose commitment and corresponding detriment per MWe.y energy produced by the uranium which corresponds to the amount of waste interest, The methods of dose commitment calculations are discussed and it is suggested for the purpose of estimation of the detriment to limit the commitment to 10,000 years. The external radiation from the tailings is easily reduced by covering but in case of a future settlement on the tailings the collective dose commitment will be some hundreds to thousands of manrad/MWe.y depending on the quality of the uranium ore. The dispersion of dust from uncovered tailings is mainly a local problem and the collective dose commitment for critical tissues in the lung will be less than a manrad/MWe.y. In the long run the cover may be lost and the resultant collective dose commitment for the critical tissues in the lung will be a few tens of manrad/MWe.y depending on the quality of the tailings. The effects of global dispersion of the material in the tailings are also discussed

Tail gut cyst.

Science.gov (United States)

Rao, G Mallikarjuna; Haricharan, P; Ramanujacharyulu, S; Reddy, K Lakshmi

2002-01-01

The tail gut is a blind extension of the hindgut into the tail fold just distal to the cloacal membrane. Remnants of this structure may form tail gut cyst. We report a 14-year-old girl with tail gut cyst that presented as acute abdomen. The patient recovered after cyst excision.

Evaluation of fox tail millet (Setaria italica forage quality in different growth stages

Directory of Open Access Journals (Sweden)

F. Izadi Yazdanabadi

2016-05-01

Full Text Available In order to evaluate the quantitative factors in fox tail millet (Setaria italica L. under three stages of growth, an experiment was conducted in Birjand during spring and summer of 2010. The preliminary objective was evaluation of fox tail physiological characteristics on animals that feed them. Planting of Foxtail millet was performed according to local practices and endemic acknowledge. Sampling was carried out at Vegetative, flowering and seeding stages, then samples transported to laboratory of animal nutrition. After Drying of sampling, dry matter, dry matter digestibility, crude protein, metabolically energy, Acid Detergent Fiber and Nitrogen Detergent Fiber, Ash and some mineral nutrients were measured. The results showed significant differences in measured characteristics in various phonological stages. Forage quality was higher in flowering and seeding stages than in vegetative stage. Dry matter digestibility and metabolically energy were high and NDF and ADF were less in vegetative stage. Because fox tail millet is leafy and palatable by animal at this stage, it’s optimum yield is important. Ability to produce Green fodder by this plant and the possibility of cultivation in different regions and its ability to produce forage for livestocks, its planting is recommended.

Device for Writing the Time Tail from Spallation Neutron Pulses

International Nuclear Information System (INIS)

Langan, P.; Schoenborn, Benno P.; Daemen, L.L.

2001-01-01

Recent work at Los Alamos Neutron Science Center (LANSCE), has shown that there are large gains in neutron beam intensity to be made by using coupled moderators at spallation neutron sources. Most of these gains result from broadening the pulse-width in time. However the accompanying longer exponential tail at large emission times can be a problem in that it introduces relatively large beam-related backgrounds at high resolutions. We have designed a device that can reshape the moderated neutron beam by cutting the time-tail so that a sharp time resolution can be re-established without a significant loss in intensity. In this work the basic principles behind the tail-cutter and some initial results of Monte Carlo simulations are described. Unwanted neutrons in the long time-tail are diffracted out of the transmitted neutron beam by a nested stack of aperiodic multi-layers, rocking at the same frequency as the source. Nested aperiodic multi-layers have recently been used at X-ray sources and as band-pass filters in quasi-Laue neutron experiments at reactor neutron sources. Optical devices that rock in synchronization with a pulsed neutron beam are relatively new but are already under construction at LANSCE. The tail-cutter described here is a novel concept that uses existing multi-layer technology in a new way for spallation neutrons. Coupled moderators in combination with beam shaping devices offer the means of increasing flux whilst maintaining a sharp time distribution. A prototype device is being constructed for the protein crystallography station at LANSCE. The protein crystallography station incorporates a water moderator that has been judiciously coupled in order to increase the flux over neutron energies that are important to structural biology (3-80meV). This development in moderator design is particularly important because protein crystallography is flux limited and because conventional ambient water and cold hydrogen moderators do not provide relatively

Flexible histone tails in a new mesoscopic oligonucleosome model.

Science.gov (United States)

Arya, Gaurav; Zhang, Qing; Schlick, Tamar

2006-07-01

We describe a new mesoscopic model of oligonucleosomes that incorporates flexible histone tails. The nucleosome cores are modeled using the discrete surface-charge optimization model, which treats the nucleosome as an electrostatic surface represented by hundreds of point charges; the linker DNAs are treated using a discrete elastic chain model; and the histone tails are modeled using a bead/chain hydrodynamic approach as chains of connected beads where each bead represents five protein residues. Appropriate charges and force fields are assigned to each histone chain so as to reproduce the electrostatic potential, structure, and dynamics of the corresponding atomistic histone tails at different salt conditions. The dynamics of resulting oligonucleosomes at different sizes and varying salt concentrations are simulated by Brownian dynamics with complete hydrodynamic interactions. The analyses demonstrate that the new mesoscopic model reproduces experimental results better than its predecessors, which modeled histone tails as rigid entities. In particular, our model with flexible histone tails: correctly accounts for salt-dependent conformational changes in the histone tails; yields the experimentally obtained values of histone-tail mediated core/core attraction energies; and considers the partial shielding of electrostatic repulsion between DNA linkers as a result of the spatial distribution of histone tails. These effects are crucial for regulating chromatin structure but are absent or improperly treated in models with rigid histone tails. The development of this model of oligonucleosomes thus opens new avenues for studying the role of histone tails and their variants in mediating gene expression through modulation of chromatin structure.

A review on in situ phytoremediation of mine tailings.

Science.gov (United States)

Wang, Li; Ji, Bin; Hu, Yuehua; Liu, Runqing; Sun, Wei

2017-10-01

Mine tailings are detrimental to natural plant growth due to their physicochemical characteristics, such as high pH, high salinity, low water retention capacity, high heavy metal concentrations, and deficiencies in soil organic matter and fertility. Thus, the remediation of mine tailings has become a key issue in environmental science and engineering. Phytoremediation, an in situ cost-effective technology, is emerging as the most promising remediation method for mine tailings by introducing tolerant plant species. It is particularly effective in dealing with large-area mine tailings with shallow contamination of organic, nutrient and metal pollutants. In this review, the background, concepts and applications of phytoremediation are comprehensively discussed. Furthermore, proper amendments used to improve the physical, chemical and biological properties of mine tailings are systematically reviewed and compared. Emphasis is placed on the types and characteristics of tolerant plants and their role in phytoremediation. Moreover, the role of microorganisms and their mechanism in phytoremediation are also discussed in-depth. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cooling equilibrium and beam loss with internal targets in high energy storage rings

International Nuclear Information System (INIS)

Boine-Frankenheim, O.; Hasse, R.; Hinterberger, F.; Lehrach, A.; Zenkevich, P.

2006-01-01

The beam cooling equilibrium with internal target interaction is analyzed for parameters relevant to the proposed High Energy Storage Ring (HESR). For the proposed experiments with anti-protons high luminosities together with low momentum spreads are required. Rate equations are used to predict the rms equilibrium beam parameters. The cooling and IBS rate coefficients are obtained from simplified models. Energy loss straggling in the target and the associated beam loss are analyzed analytically assuming a thin target. A longitudinal kinetic simulation code is used to study the evolution of the momentum distribution in coasting and bunched beams. Analytic expressions for the target induced momentum tail are found in good agreement with the simulation results

Near-threshold quantization and scattering for deep potentials with attractive tails

International Nuclear Information System (INIS)

Eltschka, Christopher; Moritz, Michael J.; Friedrich, Harald

2000-01-01

Near-threshold properties of bound and continuum states in a deep potential with an attractive tail depend essentially on a few 'tail parameters', which are determined by the properties of the potential tail beyond the region of r-values where WKB wavefunctions are accurate solutions of the Schroedinger equation. One of these tail parameters is a length parameter which defines the singular contribution to the level density just below threshold and the reflectivity of the tail of the potential just above threshold; another is a phase difference which, together with the length parameter, determines the mean scattering length. The near-threshold quantization rule and the actual scattering length are determined by the tail parameters together with a dimensionless constant depending on the zero-energy value of the WKB action integral. We study potentials with tails consisting of two inverse-power terms, V(r)∼-C α /r α -C α 1 /r α 1 ,α 1 >α>2and we derive exact analytical expressions for the tail parameters in the special case α 1 =2(α-1). This enables us to demonstrate the effect of a significant non-homogeneity of the potential tail on the results derived previously for homogeneous tails. (author)

Uranium Mill Tailings Management

International Nuclear Information System (INIS)

Nelson, J.D.

1982-01-01

This book presents the papers given at the Fifth Symposium on Uranium Mill Tailings Management. Advances made with regard to uranium mill tailings management, environmental effects, regulations, and reclamation are reviewed. Topics considered include tailings management and design (e.g., the Uranium Mill Tailings Remedial Action Project, environmental standards for uranium mill tailings disposal), surface stabilization (e.g., the long-term stability of tailings, long-term rock durability), radiological aspects (e.g. the radioactive composition of airborne particulates), contaminant migration (e.g., chemical transport beneath a uranium mill tailings pile, the interaction of acidic leachate with soils), radon control and covers (e.g., radon emanation characteristics, designing surface covers for inactive uranium mill tailings), and seepage and liners (e.g., hydrologic observations, liner requirements)

Active vertical tail buffeting suppression based on macro fiber composites

Science.gov (United States)

Zou, Chengzhe; Li, Bin; Liang, Li; Wang, Wei

2016-04-01

Aerodynamic buffet is unsteady airflow exerting forces onto a surface, which can lead to premature fatigue damage of aircraft vertical tail structures, especially for aircrafts with twin vertical tails at high angles of attack. In this work, Macro Fiber Composite (MFC), which can provide strain actuation, was used as the actuator for the buffet-induced vibration control, and the positioning of the MFC patches was led by the strain energy distribution on the vertical tail. Positive Position Feedback (PPF) control algorithm has been widely used for its robustness and simplicity in practice, and consequently it was developed to suppress the buffet responses of first bending and torsional mode of vertical tail. However, its performance is usually attenuated by the phase contributions from non-collocated sensor/actuator configuration and plants. The phase lag between the input and output signals of the control system was identified experimentally, and the phase compensation was considered in the PPF control algorithm. The simulation results of the amplitude frequency of the closed-loop system showed that the buffet response was alleviated notably around the concerned bandwidth. Then the wind tunnel experiment was conducted to verify the effectiveness of MFC actuators and compensated PPF, and the Root Mean Square (RMS) of the acceleration response was reduced 43.4%, 28.4% and 39.5%, respectively, under three different buffeting conditions.

Encounter of the Ulysses Spacecraft with the Ion Tail of Comet McNaught

Science.gov (United States)

Neugebauer, M.; Gloeckler, G.; Gosling, J. T.; Rees, A.; Skoug, R.; Goldstein, B. E.; Armstrong, T. P.; Combi, M. R.; Makinen, T.; McComas, D. J.;

More tail lesions among undocked than tail docked pigs in a conventional herd

DEFF Research Database (Denmark)

Lahrmann, H. P.; Busch, M. E.; D'Eath, R. B.

2017-01-01

The vast majority of piglets reared in the European Union (EU) and worldwide is tail docked to reduce the risk of being tail bitten, even though EU animal welfare legislation bans routine tail docking. Many conventional herds experience low levels of tail biting among tail docked pigs, however...

HARD X-RAY TAIL DISCOVERED IN THE CLOCKED BURSTER GS 1826–238

Energy Technology Data Exchange (ETDEWEB)

Rodi, J.; Jourdain, E.; Roques, J. P., E-mail: jrodi@irap.omp.eu [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France)

2016-02-01

The low-mass X-ray binary (LMXB) neutron star (NS) GS 1826–238 was discovered by Ginga in 1988 September. Due to the presence of quasi-periodicity in the type I X-ray burst rate, the source has been a frequent target of X-ray observations for almost 30 years. Though the bursts were too soft to be detected by INTEGRAL/SPI, the persistent emission from GS 1826–238 was detected over 150 keV during the ∼10 years of observations. Spectral analysis found a significant high-energy excess above a Comptonization model that is well fit by a power law, indicating an additional spectral component. Most previously reported spectra with hard tails in LMXB NS have had an electron temperature of a few keV and a hard tail dominating above ∼50 keV with an index of Γ ∼ 2–3. GS 1826–238 was found to have a markedly different spectrum with kT{sub e} ∼ 20 keV and a hard tail dominating above ∼150 keV with an index of Γ ∼ 1.8, more similar to black hole X-ray binaries. We report on our search for long-term spectral variability over the 25–370 keV energy range and on a comparison of the GS 1826–238 average spectrum to the spectra of other LMXB NSs with hard tails.

Rheological Link Between Polymer Melts with a High Molecular Weight Tail and Enhanced Formation of Shish-Kebabs

DEFF Research Database (Denmark)

Wingstrand, Sara Lindeblad; Shen, Bo; Kornfield, Julie A.

2017-01-01

Presence of an ultra high molecular weight (UHMw) fraction in flowingpolymer melts is known to facilitate formation of oriented crystalline structures significantly. The UHMw fraction manifests itself as a minor tail in the molar mass distribution and is hardly detectable in the canonical...... a clear increase in extensional stress that is directly correlated with the crystalline orientation of the quenched samples. Extensional rheology, particularly, in combination with linear creep measurements, thus, enables the conformational evolution of the UHMw-tail to be studied and linked...

Quasi-steady state aerodynamics of the cheetah tail

Directory of Open Access Journals (Sweden)

Amir Patel

2016-08-01

Full Text Available During high-speed pursuit of prey, the cheetah (Acinonyx jubatus has been observed to swing its tail while manoeuvring (e.g. turning or braking but the effect of these complex motions is not well understood. This study demonstrates the potential of the cheetah's long, furry tail to impart torques and forces on the body as a result of aerodynamic effects, in addition to the well-known inertial effects. The first-order aerodynamic forces on the tail are quantified through wind tunnel testing and it is observed that the fur nearly doubles the effective frontal area of the tail without much mass penalty. Simple dynamic models provide insight into manoeuvrability via simulation of pitch, roll and yaw tail motion primitives. The inertial and quasi-steady state aerodynamic effects of tail actuation are quantified and compared by calculating the angular impulse imparted onto the cheetah's body and its shown aerodynamic effects contribute to the tail's angular impulse, especially at the highest forward velocities.

Generation and detection of high-energy phonons by superconducting junctions

International Nuclear Information System (INIS)

Singer, I.L.

1976-01-01

Superconducting tunnel junctions are used to investigate the dynamics of energy exchange that takes place in superconductors driven out of equilibrium. In a Sn junction biased at a voltage V much greater than 2Δ(Sn)/e, the tunneling current sustains a continual energy exchange amongst the quasiparticles, phonons, and Cooper pairs. Repeatedly, high-energy quasiparticles decay, emitting phonons; and phonons with energy greater than 2Δ(Sn) break pairs, producing quasiparticles. The phonon-induced component of the current is recovered by synchronously detecting the full tunneling current with respect to a small modulation current in the generator. Sharp onsets observed at intervals of the gap energies require that the escaping phonons are produced by the direct decay of the injected quasiparticles and are not merely the high-energy tail of the thermalized phonons. Both primary and secondary phonons can be abserved distinctly. Theoretical transconductance curves have been computed. The experimental and theoretical curves are in good qualitative agreement. A more detailed comparison suggests that the escape rate of high-energy phonons depends on the energy of the phonons. The dependence of the observed transconductance signal on the temperature and the total junction thickness suggests that the presence of quasiparticles plays a major role in the escape of high-energy phonons. The dependence on temperature can be fitted to exp(b/kT), 0.74 less than b less than 1.05 MeV. It is speculated that the excitation energy is first transported across the superconductor and then carried out of the film by the phonons. It is concluded that high-energy phonons are a sensitive probe of the very reabsorption effects that make their escape so unlikely, and analysis of the detected phonons rich details of the behavior of superconductors removed from equilibrium

Anisotropic distribution function of minority tail ions generated by strong ion-cyclotron resonance heating

International Nuclear Information System (INIS)

Chang, C.S.; Colestock, P.

1989-05-01

The highly anisotropic particle distribution function of minority tail ions driven by ion-cyclotron resonance heating at the fundamental harmonic is calculated in a two-dimensional velocity space. It is assumed that the heating is strong enough to drive most of the resonant ions above the in-electron critical slowing-down energy. Simple analytic expressions for the tail distribution are obtained fro the case when the Doppler effect is sufficiently large to flatten the sharp pitch angle dependence in the bounce averaged qualilinear heating coefficient, D/sub b/, and for the case when D/sub b/ is assumed to be constant in pitch angle and energy. It is found that a simple constant-D/sub b/ solution can be used instead of the more complicated sharp-D/sub b/ solution for many analytic purposes. 4 refs., 4 figs

Nature of the band tails in one-dimensional disordered systems

International Nuclear Information System (INIS)

Brezini, A.; Sebbani, M.; Benkhaled, N.; Depollier, C.; Kergomard, J.

1995-12-01

A theoretical model for the density of states based on a tight-binding scheme for one-dimensional disordered systems is investigated within a self-consistent approach in terms of a probabilistic procedure. In particular an exact analytical expression is worked out for the density of states for the case of a Cauchy distribution for the site energies in the region of localized states. A particular attention is paid to the energies lying in the band tails. It is mainly shown that the band tails are sensitive to the typical nature of the disorder. (author). 35 refs, 1 fig

Developing a bright 17 keV x-ray source for probing high-energy-density states of matter at high spatial resolution

Energy Technology Data Exchange (ETDEWEB)

Huntington, C. M.; Park, H.-S.; Maddox, B. R.; Barrios, M. A.; Benedetti, R.; Braun, D. G.; Landen, O. L.; Wehrenberg, C. E.; Remington, B. A. [Lawrence Livermore National Laboratory, Livermore, California, 94551 (United States); Hohenberger, M.; Regan, S. P. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

2015-04-15

A set of experiments were performed on the National Ignition Facility (NIF) to develop and optimize a bright, 17 keV x-ray backlighter probe using laser-irradiated Nb foils. High-resolution one-dimensional imaging was achieved using a 15 μm wide slit in a Ta substrate to aperture the Nb He{sub α} x-rays onto an open-aperture, time integrated camera. To optimize the x-ray source for imaging applications, the effect of laser pulse shape and spatial profile on the target was investigated. Two laser pulse shapes were used—a “prepulse” shape that included a 3 ns, low-intensity laser foot preceding the high-energy 2 ns square main laser drive, and a pulse without the laser foot. The laser spatial profile was varied by the use of continuous phase plates (CPPs) on a pair of shots compared to beams at best focus, without CPPs. A comprehensive set of common diagnostics allowed for a direct comparison of imaging resolution, total x-ray conversion efficiency, and x-ray spectrum between shots. The use of CPPs was seen to reduce the high-energy tail of the x-ray spectrum, whereas the laser pulse shape had little effect on the high-energy tail. The measured imaging resolution was comparably high for all combinations of laser parameters, but a higher x-ray flux was achieved without phase plates. This increased flux was the result of smaller laser spot sizes, which allowed us to arrange the laser focal spots from multiple beams and produce an x-ray source which was more localized behind the slit aperture. Our experiments are a first demonstration of point-projection geometry imaging at NIF at the energies (>10 keV) necessary for imaging denser, higher-Z targets than have previously been investigated.

Polymer aids for settling and filtration of oil sands tailings

Energy Technology Data Exchange (ETDEWEB)

Wang, X. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering; Energy Resources Conservation Board, Calgary, AB (Canada). Oil Sands Section; Xu, Z.; Masliyah, J.H. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

2008-07-01

Oil sand tailings are segregated into coarse and fine tailings. High volumes of toxic fluids and tailings are created in the process. Tailings ponds are an environmental risk with high operating and maintenance costs. Current commercial technologies uses chemical additions to create recycled water and composite tailings (CT). Researchers are now investigating centrifuged and dry mature fine tailings (MFT). Filtration processes with flocculants are used to separate the tailings into warm recycle water and dried cakes that can be used in reclamation processes. Studies are being conducted to find a polymer than can effectively flocculate and filter whole oil sands tailings. The filtration procedure uses pressure to produce released water. Polymers include magnafloc and Al-PAM polymer concentrations are used in slurry masses. Tests have been conducted to determine the settling rates of the polymers. The tests showed that Al-PAM filtered the tailings effectively. Paraffinic froth treatment tests have also been conducted to determine settling rates. A cake produced with froth treatment tailings of Al-PAM 400 ppm had a water content 42.5 wt per cent. The tests showed that while Magnafloc 1011 is a good settling aid, but a poor filtration addition. Al-PAM aided in both the flocculation and filtration processes. Higher Al-PAM dosages are needed for froth treatment tailings processes. It was concluded that dry cakes are produced with the addition of Al-PAM. tabs., figs.

Presentations of the CONRAD tailings seminar : exploring the past, present and future of tailings technologies

International Nuclear Information System (INIS)

2004-01-01

This symposium explored oil sand tailings activities in Canada and their associated technologies. It was attended by active and prospective tailings researchers and developers of tailings technology who addressed timely issues regarding mature fine tailings, consolidated tailings, thickened tailings, and emerging tailings technologies. The collaborative research projects that are underway at the Oil Sands Tailings Research Facility were also discussed along with other topics such as tailings ponds management, water treatment, water quality and water supply security. All 16 presentations featured at this conference were indexed separately for inclusion in this database

Confinement characteristics of high-energy ions produced by ICRF heating in the large helical device

International Nuclear Information System (INIS)

Kumazawa, R; Saito, K; Torii, Y; Mutoh, T; Seki, T; Watari, T; Osakabe, M; Murakami, S; Sasao, M; Watanabe, T; Yamamoto, T; Notake, T; Takeuchi, N; Saida, T; Shimpo, F; Nomura, G; Yokota, M; Kato, A; Zao, Y; Okada, H; Isobe, M; Ozaki, T; Narihara, K; Nagayama, Y; Inagaki, S; Morita, S; Krasilnikov, A V; Idei, H; Kubo, S; Ohkubo, K; Sato, M; Shimozuma, T; Yoshimura, Y; Ikeda, K; Nagaoka, K; Oka, Y; Takeiri, Y; Tsumori, K; Ashikawa, N; Emoto, M; Funaba, H; Goto, M; Ida, K; Kobuchi, T; Liang, Y; Masuzaki, S; Minami, T; Miyazawa, J; Morisaki, T; Muto, S; Nakamura, Y; Nakanishi, H; Nishimura, K; Noda, N; Ohdachi, S; Peterson, B J; Sagara, A; Sakakibara, S; Sakamoto, R; Sato, K; Shoji, M; Suzuki, H; Tanaka, K; Toi, K; Tokuzawa, T; Watanabe, K Y; Yamada, I; Yamamoto, S; Yoshinuma, M; Yokoyama, M; Watanabe, K-Y; Kaneko, O; Kawahata, K; Komori, A; Ohyabu, N; Yamada, H; Yamazaki, K; Sudo, S; Matsuoka, K; Hamada, Y; Motojima, O; Fujiwara, M

2003-01-01

The behaviour of high-energy ions accelerated by an ion cyclotron range of frequency (ICRF) electric field in the large helical device (LHD) is discussed. A better confinement performance of high-energy ions in the inward-shifted magnetic axis configuration was experimentally verified by measuring their energy spectrum and comparing it with the effective temperature determined by an electron slowing down process. In the standard magnetic axis configuration a saturation of the measured tail temperature was observed as the effective temperature was increased. The ratio between these two quantities is a measure of the quality of transfer efficiency from high-energy ions to a bulk plasma; when this efficiency was compared with Monte Carlo simulations the results agreed fairly well. The ratio of the stored energy of the high-energy ions to that of the bulk plasma was measured using an ICRF heating power modulation method; it was deduced from phase differences between total and bulk plasma stored energies and the modulated ICRF heating power. The measured high energy fraction agreed with that calculated using the injected ICRF heating power, the transfer efficiency determined in the experiment and the confinement scaling of the LHD plasma

Accelerated aging tests of liners for uranium mill tailings disposal

International Nuclear Information System (INIS)

Barnes, S.M.; Buelt, J.L.; Hale, V.Q.

1981-11-01

This document describes the results of accelerated aging tests to determine the long-term effectiveness of selected impoundment liner materials in a uranium mill tailings environment. The study was sponsored by the US Department of Energy under the Uranium Mill Tailings Remedial Action Project. The study was designed to evaluate the need for, and the performance of, several candidate liners for isolating mill tailings leachate in conformance with proposed Environmental Protection Agency and Nuclear Regulatory Commission requirements. The liners were subjected to conditions known to accelerate the degradation mechanisms of the various liners. Also, a test environment was maintained that modeled the expected conditions at a mill tailings impoundment, including ground subsidence and the weight loading of tailings on the liners. A comparison of installation costs was also performed for the candidate liners. The laboratory testing and cost information prompted the selection of a catalytic airblown asphalt membrane and a sodium bentonite-amended soil for fiscal year 1981 field testing

Galaxies with long tails

International Nuclear Information System (INIS)

Schweizer, F.

1978-01-01

Two types of galaxies with long tails are described. The first occurs in pairs, each individual one having a long tail and the second occurs on its own with two tails. NGC 7252 shows several characteristics which one would expect of a merger: a pair of tidal tails despite the splendid isolation, a single nucleus, tail motions in opposite directions relative to the nucleus, and chaotic motions of a strangely looped main body. (C.F.)

Mine Waste Technology Program Electrochemical Tailings Cover

Science.gov (United States)

This report summarizes the results of Mine Waste Technology Program (MWTP) Activity III, Project 40, Electrochemical Tailings Cover, funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U.S. Department of Energy (DOE). MSE Technology A...

Attitudes of Dutch Pig Farmers Towards Tail Biting and Tail Docking

OpenAIRE

Bracke, M.B.M.; Lauwere, de, C.C.; Wind, S.M.M.; Zonderland, J.J.

2013-01-01

The Dutch policy objective of a fully sustainable livestock sector without mutilations by 2023 is not compatible with the routine practice of tail docking to minimize the risk of tail biting. To examine farmer attitudes towards docking, a telephone survey was conducted among 487 conventional and 33 organic Dutch pig farmers. “Biting” (of tails, ears, or limbs) was identified by the farmers as a main welfare problem in pig farming. About half of the farmers reported to have no tail biting prob...

Manual for the sampling of uranium mine tailings

International Nuclear Information System (INIS)

Feenstra, S.; Reades, D.W.; Cherry, J.A.; Chambers, D.B.; Case, G.G.; Ibbotson, B.G.

1983-04-01

The purpose of this manual is to describe the requisite sampling procedures to provide a basis for the application of uniform high-quality standards to detailed geotechnical, hydrogeological, geochemical and air quality measurements at Canadian uranium tailings disposal sites. The report describes the objective and scope of a sampling program, the preliminary data collection, and the procedures for sampling of tailings solids, surface water and seepage, tailings porewater, and wind-blown dust and radon

A nonluminescent and highly virulent Vibrio harveyi strain is associated with "bacterial white tail disease" of Litopenaeus vannamei shrimp.

Directory of Open Access Journals (Sweden)

Junfang Zhou

Full Text Available Recurrent outbreaks of a disease in pond-cultured juvenile and subadult Litopenaeus vannamei shrimp in several districts in China remain an important problem in recent years. The disease was characterized by "white tail" and generally accompanied by mass mortalities. Based on data from the microscopical analyses, PCR detection and 16S rRNA sequencing, a new Vibrio harveyi strain (designated as strain HLB0905 was identified as the etiologic pathogen. The bacterial isolation and challenge tests demonstrated that the HLB0905 strain was nonluminescent but highly virulent. It could cause mass mortality in affected shrimp during a short time period with a low dose of infection. Meanwhile, the histopathological and electron microscopical analysis both showed that the HLB0905 strain could cause severe fiber cell damages and striated muscle necrosis by accumulating in the tail muscle of L. vannamei shrimp, which led the affected shrimp to exhibit white or opaque lesions in the tail. The typical sign was closely similar to that caused by infectious myonecrosis (IMN, white tail disease (WTD or penaeid white tail disease (PWTD. To differentiate from such diseases as with a sign of "white tail" but of non-bacterial origin, the present disease was named as "bacterial white tail disease (BWTD". Present study revealed that, just like IMN and WTD, BWTD could also cause mass mortalities in pond-cultured shrimp. These results suggested that some bacterial strains are changing themselves from secondary to primary pathogens by enhancing their virulence in current shrimp aquaculture system.

Quasi-steady state aerodynamics of the cheetah tail.

Science.gov (United States)

Patel, Amir; Boje, Edward; Fisher, Callen; Louis, Leeann; Lane, Emily

2016-08-15

During high-speed pursuit of prey, the cheetah (Acinonyx jubatus) has been observed to swing its tail while manoeuvring (e.g. turning or braking) but the effect of these complex motions is not well understood. This study demonstrates the potential of the cheetah's long, furry tail to impart torques and forces on the body as a result of aerodynamic effects, in addition to the well-known inertial effects. The first-order aerodynamic forces on the tail are quantified through wind tunnel testing and it is observed that the fur nearly doubles the effective frontal area of the tail without much mass penalty. Simple dynamic models provide insight into manoeuvrability via simulation of pitch, roll and yaw tail motion primitives. The inertial and quasi-steady state aerodynamic effects of tail actuation are quantified and compared by calculating the angular impulse imparted onto the cheetah's body and its shown aerodynamic effects contribute to the tail's angular impulse, especially at the highest forward velocities. © 2016. Published by The Company of Biologists Ltd.

Sharp-Tailed Grouse Nest Survival and Nest Predator Habitat Use in North Dakota's Bakken Oil Field.

Directory of Open Access Journals (Sweden)

Paul C Burr

Full Text Available Recent advancements in extraction technologies have resulted in rapid increases of gas and oil development across the United States and specifically in western North Dakota. This expansion of energy development has unknown influences on local wildlife populations and the ecological interactions within and among species. Our objectives for this study were to evaluate nest success and nest predator dynamics of sharp-tailed grouse (Tympanuchus phasianellus in two study sites that represented areas of high and low energy development intensities in North Dakota. During the summers of 2012 and 2013, we monitored 163 grouse nests using radio telemetry. Of these, 90 nests also were monitored using miniature cameras to accurately determine nest fates and identify nest predators. We simultaneously conducted predator surveys using camera scent stations and occupancy modeling to estimate nest predator occurrence at each site. American badgers (Taxidea taxus and striped skunks (Mephitis mephitis were the primary nest predators, accounting for 56.7% of all video recorded nest depredations. Nests in our high intensity gas and oil area were 1.95 times more likely to succeed compared to our minimal intensity area. Camera monitored nests were 2.03 times more likely to succeed than non-camera monitored nests. Occupancy of mammalian nest predators was 6.9 times more likely in our study area of minimal gas and oil intensity compared to the high intensity area. Although only a correlative study, our results suggest energy development may alter the predator community, thereby increasing nest success for sharp-tailed grouse in areas of intense development, while adjacent areas may have increased predator occurrence and reduced nest success. Our study illustrates the potential influences of energy development on the nest predator-prey dynamics of sharp-tailed grouse in western North Dakota and the complexity of evaluating such impacts on wildlife.

CT energy weighting in the presence of scatter and limited energy resolution

International Nuclear Information System (INIS)

Schmidt, Taly Gilat

2010-01-01

Purpose: Energy-resolved CT has the potential to improve the contrast-to-noise ratio (CNR) through optimal weighting of photons detected in energy bins. In general, optimal weighting gives higher weight to the lower energy photons that contain the most contrast information. However, low-energy photons are generally most corrupted by scatter and spectrum tailing, an effect caused by the limited energy resolution of the detector. This article first quantifies the effects of spectrum tailing on energy-resolved data, which may also be beneficial for material decomposition applications. Subsequently, the combined effects of energy weighting, spectrum tailing, and scatter are investigated through simulations. Methods: The study first investigated the effects of spectrum tailing on the estimated attenuation coefficients of homogeneous slab objects. Next, the study compared the CNR and artifact performance of images simulated with varying levels of scatter and spectrum tailing effects, and reconstructed with energy integrating, photon-counting, and two optimal linear weighting methods: Projection-based and image-based weighting. Realistic detector energy-response functions were simulated based on a previously proposed model. The energy-response functions represent the probability that a photon incident on the detector at a particular energy will be detected at a different energy. Realistic scatter was simulated with Monte Carlo methods. Results: Spectrum tailing resulted in a negative shift in the estimated attenuation coefficient of slab objects compared to an ideal detector. The magnitude of the shift varied with material composition, increased with material thickness, and decreased with photon energy. Spectrum tailing caused cupping artifacts and CT number inaccuracies in images reconstructed with optimal energy weighting, and did not impact images reconstructed with photon counting weighting. Spectrum tailing did not significantly impact the CNR in reconstructed images

Recovery of iron from cyanide tailings with reduction roasting–water leaching followed by magnetic separation

International Nuclear Information System (INIS)

Zhang, Yali; Li, Huaimei; Yu, Xianjin

2012-01-01

Highlights: ► Using reduction roasting–water leaching–magnetic separation method, the recovery of iron from cyanide tailings was optimized. ► The recovery of iron was highly depended on the water-leaching process after reduction roasting. ► The results suggest that the method can be effectively used for iron recovery, and the grade of magnetic concentrate and recovery rate can reach 59.11% and 75.12%, respectively. - Abstract: Cyanide tailing is a kind of solid waste produced in the process of gold extraction from gold ore. In this paper, recovery of iron from cyanide tailings was studied with reduction roasting–water leaching process followed by magnetic separation. After analysis of chemical composition and crystalline phase, the effects of different parameters on recovery of iron were chiefly introduced. Systematic studies indicate that the high recovery rate and grade of magnetic concentrate of iron can be achieved under the following conditions: weight ratios of cyanide tailings/activated carbon/sodium carbonate/sodium sulfate, 100:10:3:10; temperature, 50 °C; time, 60 min at the reduction roasting stage; the liquid to solid ratio is 15:1 (ml/g), leaching at 60 °C for 5 min and stirring speed at 20 r/min at water-leaching; exciting current is 2 A at magnetic separation. The iron grade of magnetic concentrate was 59.11% and the recovery ratio was 75.12%. The mineralography of cyanide tailings, roasted product, water-leached sample, magnetic concentrate and magnetic tailings were studied by X-ray powder diffraction (XRD) technique. The microstructures of above products except magnetic tailings were also analyzed by scanning electron microscope (SEM) and energy disperse spectroscopy (EDS) to help understand the mechanism.

Bar-tailed

NARCIS (Netherlands)

Duijns, S.; Hidayati, N.A.; Piersma, T.

2013-01-01

Capsule Across the European wintering range Bar-tailed Godwits Limosa lapponica lapponica selected polychaete worms and especially Ragworms Hediste diversicolor, with differences between areas due to variations in prey availability.Aims To determine the diet of Bar-tailed Godwits across their

Large-scale interaction of the solar wind with cometary plasma tails

International Nuclear Information System (INIS)

Niedner, M.B. Jr.

1979-01-01

The study of the behavior of plasma tails in the context of their interaction with the solar wind could have important implications for the structure of the interplanetary medium in three dimensions. Comet Kohoutek 1973f exhibited a broad range of plasma tail behavior. On 1974 January 20, the tail was in a highly disturbed condition. Comet Kohoutek was encountering the leading edge of a very strong high-speed stream at the time the plasma tail disturbance started to develop. Comparison of the observed tail geometry on January 20 with the theoretical position angles generated from the wind sock theory of plasma tails and the corotated satellite observations shows that the tail disturbance was probably caused by large gradients of the polar component of the solar-wind velocity. Within hours after the disturbance of January 20, the plasma tail of comet Kohoutek became disconnected from the cometary head, and was replaced by a new plasma tail. The comet was very near an interplanetary sector boundary at the time of disconnection. The disconnection event (DE) is suggested to have resulted from the magnetic reconnection of plasma tail field lines. A similar analysis of other DEs found in original plate material and in published photographs shows the most DEs occur near corotated sector boundaries. Thus, the sector boundary model is further supported, and the finding provides the only known method of probing sector structure to high latitudes. Sector boundaries can often extend to high latitudes in a nearly North-South orientation, and this property is not restricted to times away from solar minimum. Furthermore, the boundaries are inferred to be randomly tilted with respect to the polarity sequence across the boundary and to the magnetic signs of the solar poles

TAIL ASYMPTOTICS OF LIGHT-TAILED WEIBULL-LIKE SUMS

DEFF Research Database (Denmark)

Asmussen, Soren; Hashorva, Enkelejd; Laub, Patrick J.

2017-01-01

We consider sums of n i.i.d. random variables with tails close to exp{-x(beta)} for some beta > 1. Asymptotics developed by Rootzen (1987) and Balkema, Kluppelberg, and Resnick (1993) are discussed from the point of view of tails rather than of densities, using a somewhat different angle...

Effects of weather and tailings properties on tailings drying times

Energy Technology Data Exchange (ETDEWEB)

Gantzer, C.; Fasking, T.; Costello, M.; Greenwood, J. [Barr Engineering, Calgary, AB (Canada)

2010-07-01

This PowerPoint presentation presented the results of a study conducted to determine the effects of weather and tailings properties on tailings drying times. Weather conditions have a significant impact the potential evaporation (PE) and actual evaporation (AE) of oil sands tailings. A 2-stage drying of slurry at a constant PE was conducted to determine the shrinkage limit of untreated mature fine tailings (MFT). An evaporation and seepage model was used to determine maximum first-stage drying rates. Measurements were also taken in a wind tunnel. Potential evaporation rates were calculated and evaporative water losses from the MFT were determined. Estimated drying times were presented. Results of the approach were compared with field measurements conducted in a previous study. Results of the study showed that evaporative water loss rates for May through August were limited by the properties of the tailings. Water loss rates were limited by weather for other months in the year-long study. tabs., figs.

Cameco engineered tailings program: linking research with industrial processes for improved tailings performance

International Nuclear Information System (INIS)

Kotzer, T.; Hendry, M.J.

2011-01-01

The waste product from uranium mining and milling that generates the greatest public and regulatory concern is tailings. The tailings contain all of the mined material except uranium plus a host of processing reagents. These minerals and compounds have the potential to harm the local environment if not deposited in a fashion that is both geochemically and geotechnically stable. Environmental leadership impels Cameco Corporation to ensure that the methods used to dispose of tailings are at the forefront of best available technologies whereby tailings production results in a product with geotechnical and geochemical characteristics that minimize the environmental impact associated with long-term storage of this product. Cameco has developed an Engineered Tailings (ET) program to ensure optimization of long-term tailings performance and minimal impacts of elements of concern (EOCs) to the receiving environment, regardless of the ore being milled. Within this program chemical and physical performance of tailings from geochemical and geotechnical investigations and baseline environmental data, integrated with regulatory requirements and corporate commitments, will be used to evaluate and set criteria for mill- and tailings management facilities-based chemical and physical tailings characteristics, identify key knowledge gaps, prioritize areas of concern and implement appropriate responses. This paper provides an overview of the Engineered Tailings program, the research being conducted as part of the ET program, and how it links with present and future Cameco operations. (author)

Consistency based correlations for tailings consolidation

Energy Technology Data Exchange (ETDEWEB)

Azam, S.; Paul, A.C. [Regina Univ., Regina, SK (Canada). Environmental Systems Engineering

2010-07-01

The extraction of oil, uranium, metals and mineral resources from the earth generates significant amounts of tailings slurry. The tailings are contained in a disposal area with perimeter dykes constructed from the coarser fraction of the slurry. There are many unique challenges pertaining to the management of the containment facilities for several decades beyond mine closure that are a result of the slow settling rates of the fines and the high standing toxic waters. Many tailings dam failures in different parts of the world have been reported to result in significant contaminant releases causing public concern over the conventional practice of tailings disposal. Therefore, in order to reduce and minimize the environmental footprint, the fluid tailings need to undergo efficient consolidation. This paper presented an investigation into the consolidation behaviour of tailings in conjunction with soil consistency that captured physicochemical interactions. The paper discussed the large strain consolidation behaviour (volume compressibility and hydraulic conductivity) of six fine-grained soil slurries based on published data. The paper provided background information on the study and presented the research methodology. The geotechnical index properties of the selected materials were also presented. The large strain consolidation, volume compressibility correlations, and hydraulic conductivity correlations were provided. It was concluded that the normalized void ratio best described volume compressibility whereas liquidity index best explained the hydraulic conductivity. 17 refs., 3 tabs., 4 figs.

Blast densification trials for oilsands tailings

Energy Technology Data Exchange (ETDEWEB)

Port, A. [Klohn Crippen Berger Ltd., Vancouver, BC (Canada); Martens, S. [Klohn Crippen Berger Ltd., Calgary, AB (Canada); Eaton, T. [Shell Canada Ltd., Calgary, AB (Canada)

2010-07-01

The Shell Canada Muskeg River Mine External Tailings Facility (ETF) is an upstream constructed tailings facility located near Fort McMurray, Alberta. Raises have incrementally stepped out over the beach since construction of the starter dam and deposition within standing water has left some parts of the beach in a loose state. In order to assess the effectiveness of blast densification, a blast densification trial program that was conducted in 2006 at the ETF. The primary purpose of the test program was to determine the effectiveness of blast densification in tailings containing layers and zones of bitumen. The paper described the site characterization and explosive compaction trial program, with particular reference to test layout; drilling methodology; and blasting and timing sequence. The paper also described the instrumentation, including the seismographs; high pressure electric piezometers; low pressure electric piezometers; vibrating wire piezometers; inclinometers; settlement gauges; and surveys. Trial observations and post-trial observations were also presented. It was concluded that controlled blasting techniques could be used to safely induce liquefaction in localized areas within the tailings deposit, with a resulting increase in the tailings density. 5 refs., 1 tab., 14 figs.

Uranium tailings in the public eye

International Nuclear Information System (INIS)

Lyon, B.

1976-01-01

The ORNL field team visits to Grand Junction, Colorado, and to other sources of uranium mill tailings, are described. The radioactive hazards of these tailings, which are principally due to Th, Ra, Rn, and radon daughters, are discussed briefly. Government actions which were taken as a result of public concern are listed. The ORNL Health Physics Division mobile laboratory van and its use in assessing the tailings piles at Salt Lake City and elsewhere are described. The highest γ-ray background found was 155 mRem/y, with levels being as high as 1750 mRem/y near points of public access to piles. Some possible solutions to the problem are discussed

The structure of nuclear states at low, intermediate and high excitation energies

International Nuclear Information System (INIS)

Soloviev, V.G.

1976-01-01

It is shown that within the model based on the quasiparticle-phonon interaction one can obtain the description of few-quasiparticle components of nuclear states at low, intermediate and high excitation energies. For the low-lying states the energy of each level is calculated. The few-quasiparticle components at intermediate and high excitation energies are represented to be averaged in certain energy intervals and their characteri stics are given as the corresponding strength functions. The fragmentation of single-particle states in deformed nuclei is studied. It is shown that in the distribution of the single-particle strength alongside with a large maximum there appear local maxima and the distribution itself has a long tail. The dependence of neutron strength functions on the excitation energy is investigated for the transfer reaction of the type (d,p) and (d,t). The s,- p,- and d-wave neutron strength functions are calculated at the neutron binding energy Bn. A satisfactory agreement with experiment is obtained. The energies and Elambda-strength functions for giant multipole resonances in deformed nuclei are calculated. The energies of giant quadrupole and octupole resonances are calculated. Their widths and fine structure are being studied. It is stated that to study the structure of highly excited states it is necessary to find the values of many-quasiparticle components of the wave functions. The ways of experimental determination of these components based on the study of γ-transitions between highly excited states are discussed

Soil-covered strategy for ecological restoration alters the bacterial community structure and predictive energy metabolic functions in mine tailings profiles.

Science.gov (United States)

Li, Yang; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

2017-03-01

Native soil amendment has been widely used to stabilize mine tailings and speed up the development of soil biogeochemical functions before revegetation; however, it remains poorly understood about the response of microbial communities to ecological restoration of mine tailings with soil-covered strategy. In this study, microbial communities along a 60-cm profile were investigated in mine tailings during ecological restoration of two revegetation strategies (directly revegetation and native soil covered) with different plant species. The mine tailings were covered by native soils as thick as 40 cm for more than 10 years, and the total nitrogen, total organic carbon, water content, and heavy metal (Fe, Cu, and Zn) contents in the 0-40 cm intervals of profiles were changed. In addition, increased microbial diversity and changed microbial community structure were also found in the 10-40 cm intervals of profiles in soil-covered area. Soil-covered strategy rather than plant species and soil depth was the main factor influencing the bacterial community, which explained the largest portion (29.96%) of the observed variation. Compared directly to revegetation, soil-covered strategy exhibited the higher relative abundance of Acidobacteria and Deltaproteobacteria and the lower relative abundance of Bacteroidetes, Gemmatimonadetes, Betaproteobacteria, and Gammaproteobacteria. PICRUSt analysis further demonstrated that soil-covered caused energy metabolic functional changes in carbon, nitrogen, and sulfur metabolism. Given all these, the soil-covered strategy may be used to fast-track the establishment of native microbial communities and is conducive to the rehabilitation of biogeochemical processes for establishing native plant species.

Interactions of tailings leachate with local liner materials found at Canonsburg, Pennsylvania

International Nuclear Information System (INIS)

Dodson, M.E.; Gee, G.W.; Serne, R.J.

1984-04-01

The mill tailings site at Canonsburg, Pennsylvania is the first mill site to receive remedial action under the Department of Energy's Uranium Mill Tailings Remedial Action Program. Part of this remedial action will require excavating the 53,500 m 3 (70,000 yd 3 ) of tailings on the site having a specific activity exceeding 100 pCi/g, and encapsulating these contaminated tailings in a clay-lined cell. As part of the remedial action effort, Pacific Northwest Laboratory has been studying the interactions of tailings and tailings leachate with locally occurring clays proposed for liner materials. These studies include physical and chemical characterization of amended and unamended local clays, chemical characterization of the tailings, column studies of tailings leached with deionized water, and column studies of clays contacted with tailings solutions to determine the attenuation properties of the proposed liner materials. Column studies of tailings leached with deionized water indicated that the Canonsburg tailings could represent a source of soluble radium-226 and uranium-238, several trace metals, cations, and the anions SO 4 , NO 3 , and Cl. Of these soluble contaminants, uranium-238, radium-226, the trace metals As and Mo, and the anions F and SO 4 were present at levels exceeding maximum concentration levels in the tailings leaching column effluents. However, local clays, both in amended and unamended form were effective in attenuating contaminant migration. The soil amendments tested failed to increase radium attenuation. The tailings leaching studies indicated that the tailings will produce leachates of neutral pH and relatively low contaminant levels for at least 200 years. We believe that compacting the tailings within the encapsulation cell will help to reduce leaching of contaminants from the liner system, since very low permeabilities ( -8 cm/s) were observed for even slightly compacted tailings materials

About necessity of remediation and re-cultivation of Taboshar districts' tailings

International Nuclear Information System (INIS)

Salomov, J.A.; Mirsaidov, I.U.; Barotov, A.M.

2012-01-01

Taboshar uranium deposit is one of the oldest sites of uranium industry and reprocessing in former USSR. During geological survey in 1926 close to Istiklol city (former Taboshar), relatively high radioactivity was revealed on present territory and in 1927 the physical exploration of uranium-containing zones was completed. Active extraction of ore was carried out here from 1945 till 1965 y. Nowadays it is a huge territory with total area of more than 400 hectares covered by surface wastes tailings of hydrometallurgical reprocessing of uranium ores. Disposal complex consists from non-preserved open pit ('Factory of barren ores'), destroyed industrial buildings and four tailings (Tailing I-II, Tailing III, Tailing IV and tailing of industrial workshop 3), containing approximately 55 million tons of wastes, from which approximately 12 million tons are uranium ore's wastes. Total area of four tailing and 'Factory of barren ores' is 63 hectares. Besides, balanced-off ores and overburden rocks i.e. ores and rocks unprofitable for reprocessing should be included here as well. Factor analysis of radiation danger carried out by IAEA expert mission in Istiklol city revealed that radon content in air and aerosol contamination is not a factor of considerable radiation risk for city residents, besides cases of their visit to tailings and living of people directly within zones of their location since territory is well aired out. However, due to bad coverage of tailing, drainage waters draining from zones of their location are highly contaminated by radionuclides and contain high concentrations of manganese, sodium, lead and iron. Drainage waters of former flooded uranium mines and open pits are also considerably contaminated. Such contaminated waters are used all over by local population for cattle watering, watering of garden territories and even for drinking. Thus, the use of drainage and mine waters with high contamination level for drinking and household needs in Istiklol

The importance of band tail recombination on current collection and open-circuit voltage in CZTSSe solar cells

Energy Technology Data Exchange (ETDEWEB)

Moore, James E. [Naval Research Laboratory, Washington, DC 20375 (United States); Purdue University, West Lafayette, Indiana 47907 (United States); Hages, Charles J. [Purdue University, West Lafayette, Indiana 47907 (United States); Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Agrawal, Rakesh; Lundstrom, Mark S.; Gray, Jeffery L. [Purdue University, West Lafayette, Indiana 47907 (United States)

2016-07-11

Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) solar cells typically exhibit high short-circuit current density (J{sub sc}), but have reduced cell efficiencies relative to other thin film technologies due to a deficit in the open-circuit voltage (V{sub oc}), which prevent these devices from becoming commercially competitive. Recent research has attributed the low V{sub oc} in CZTSSe devices to small scale disorder that creates band tail states within the absorber band gap, but the physical processes responsible for this V{sub oc} reduction have not been elucidated. In this paper, we show that carrier recombination through non-mobile band tail states has a strong voltage dependence and is a significant performance-limiting factor, and including these effects in simulation allows us to simultaneously explain the V{sub oc} deficit, reduced fill factor, and voltage-dependent quantum efficiency with a self-consistent set of material parameters. Comparisons of numerical simulations to measured data show that reasonable values for the band tail parameters (characteristic energy, capture rate) can account for the observed low V{sub oc}, high J{sub sc}, and voltage dependent collection efficiency. These results provide additional evidence that the presence of band tail states accounts for the low efficiencies of CZTSSe solar cells and further demonstrates that recombination through non-mobile band tail states is the dominant efficiency limiting mechanism.

Uranium tailings bibliography

International Nuclear Information System (INIS)

Holoway, C.F.; Goldsmith, W.A.; Eldridge, V.M.

1975-12-01

A bibliography containing 1,212 references is presented with its focus on the general problem of reducing human exposure to the radionuclides contained in the tailings from the milling of uranium ore. The references are divided into seven broad categories: uranium tailings pile (problems and perspectives), standards and philosophy, etiology of radiation effects, internal dosimetry and metabolism, environmental transport, background sources of tailings radionuclides, and large-area decontamination

Metal mobilization under alkaline conditions in ash-covered tailings.

Science.gov (United States)

Lu, Jinmei; Alakangas, Lena; Wanhainen, Christina

2014-06-15

The aim of this study was to determine element mobilization and accumulation in mill tailings under alkaline conditions. The tailings were covered with 50 cm of fly ash, and above a sludge layer. The tailings were geochemically and mineralogically investigated. Sulfides, such as pyrrhotite, sphalerite and galena along with gangue minerals such as dolomite, calcite, micas, chlorite, epidote, Mn-pyroxene and rhodonite were identified in the unoxidized tailings. The dissolution of the fly ash layer resulted in a high pH (close to 12) in the underlying tailings. This, together with the presence of organic matter, increased the weathering of the tailings and mobilization of elements in the uppermost 47 cm of the tailings. All primary minerals were depleted, except quartz and feldspar which were covered by blurry secondary carbonates. Sulfide-associated elements such as Cd, Fe, Pb, S and Zn and silicate-associated elements such as Fe, Mg and Mn were released from the depletion zone and accumulated deeper down in the tailings where the pH decreased to circum-neutral. Sequential extraction suggests that Cd, Cu, Fe, Pb, S and Zn were retained deeper down in the tailings and were mainly associated with the sulfide phase. Calcium, Cr, K and Ni released from the ash layer were accumulated in the uppermost depletion zone of the tailings. Copyright © 2014 Elsevier Ltd. All rights reserved.

Performance Comparison between Neutralization Tailings and Flotation Tailings Used for Backfill Mix and Mechanism Analysis

Directory of Open Access Journals (Sweden)

Bin Han

2016-01-01

Full Text Available A comparison test of different tailings used for underground backfill was conducted, using neutralized tailings from BIOX and flotation tailings of Jinfeng Mine. Laboratory comparison test results show that, with neutralized tailings, when the cement dosage is at 19%, backfill UCS after 7 days, 14 days, and 28 days are 105%–163%, 80%–102%, and 33%–43%, respectively, which are higher than those of flotation tailings. When the cement dosage is at 12%, backfill UCS after 7 days, 14 days, and 28 days are 58%–77%, 50%–60%, and 28%–51%, respectively, which are higher than those of flotation tailings. Slurry fluidity of neutralized tailings is lower than that of flotation tailings, while, in these two tailings, the difference of slump and diffusivity values is less than 6%, which is not a significant difference in slurry fluidity. The reason for neutralized tailings showing higher UCS is as follows: during backfill curing, neutralization tailings produce abundant crystals of CaSO4·2H2O in interlaced structure which helps in combining aggregates closely; CaSO4·2H2O hydrates with C3A C4AF contained in the cement and forms clavate cement bacillus which works as a micro reinforcing steel bar. The test proved that neutralized tailings are more optimal for backfilling.

Current practices and options for confinement of uranium mill tailings

International Nuclear Information System (INIS)

1981-01-01

At the United Nations Conference on the Human Environment, which took place in Stockholm from 4 to 6 June 1972, national governments were asked to explore, with the International Atomic Energy Agency and other appropriate international organizations, international co-operation on radioactive waste matters including those of mining and tailings disposal. Since that time the IAEA has been active in the field of uranium and thorium mill tailings management. As part of this activity, the present report describes current practices and options for confinement of uranium mill tailings. It is addressed to technical and administrative personnel who are involved in planning and implementing national and industrial programmes on the management of such tailings. In 1974 and 1975 the IAEA convened meetings of experts to review matters of interest and importance in the management of uranium and thorium mine and mill tailings. These activities led to the publication in 1976 of Management of Wastes from the Mining and Milling of Uranium and Thorium Ores, a Code of Practice and Guide to the Code, IAEA Safety Series No. 44. As a continuation of this activity, the IAEA is here dealing more specifically with the design and siting considerations for the management of uranium mill tailings

Moth tails divert bat attack: evolution of acoustic deflection.

Science.gov (United States)

Barber, Jesse R; Leavell, Brian C; Keener, Adam L; Breinholt, Jesse W; Chadwell, Brad A; McClure, Christopher J W; Hill, Geena M; Kawahara, Akito Y

2015-03-03

Adaptations to divert the attacks of visually guided predators have evolved repeatedly in animals. Using high-speed infrared videography, we show that luna moths (Actias luna) generate an acoustic diversion with spinning hindwing tails to deflect echolocating bat attacks away from their body and toward these nonessential appendages. We pit luna moths against big brown bats (Eptesicus fuscus) and demonstrate a survival advantage of ∼ 47% for moths with tails versus those that had their tails removed. The benefit of hindwing tails is equivalent to the advantage conferred to moths by bat-detecting ears. Moth tails lured bat attacks to these wing regions during 55% of interactions between bats and intact luna moths. We analyzed flight kinematics of moths with and without hindwing tails and suggest that tails have a minimal role in flight performance. Using a robust phylogeny, we find that long spatulate tails have independently evolved four times in saturniid moths, further supporting the selective advantage of this anti-bat strategy. Diversionary tactics are perhaps more common than appreciated in predator-prey interactions. Our finding suggests that focusing on the sensory ecologies of key predators will reveal such countermeasures in prey.

Fishnet model for failure probability tail of nacre-like imbricated lamellar materials

Science.gov (United States)

Luo, Wen; Bažant, Zdeněk P.

2017-12-01

Nacre, the iridescent material of the shells of pearl oysters and abalone, consists mostly of aragonite (a form of CaCO3), a brittle constituent of relatively low strength (≈10 MPa). Yet it has astonishing mean tensile strength (≈150 MPa) and fracture energy (≈350 to 1,240 J/m2). The reasons have recently become well understood: (i) the nanoscale thickness (≈300 nm) of nacre's building blocks, the aragonite lamellae (or platelets), and (ii) the imbricated, or staggered, arrangement of these lamellea, bound by biopolymer layers only ≈25 nm thick, occupying engineering applications, however, the failure probability of ≤10-6 is generally required. To guarantee it, the type of probability density function (pdf) of strength, including its tail, must be determined. This objective, not pursued previously, is hardly achievable by experiments alone, since >10^8 tests of specimens would be needed. Here we outline a statistical model of strength that resembles a fishnet pulled diagonally, captures the tail of pdf of strength and, importantly, allows analytical safety assessments of nacreous materials. The analysis shows that, in terms of safety, the imbricated lamellar structure provides a major additional advantage—˜10% strength increase at tail failure probability 10^-6 and a 1 to 2 orders of magnitude tail probability decrease at fixed stress. Another advantage is that a high scatter of microstructure properties diminishes the strength difference between the mean and the probability tail, compared with the weakest link model. These advantages of nacre-like materials are here justified analytically and supported by millions of Monte Carlo simulations.

Small-scale field test of simple earthen covers for uranium mill tailings

International Nuclear Information System (INIS)

Nielson, K.K.; Rogers, V.C.; Rich, D.C.

1983-01-01

A series of field tests has been conducted during the past year to provide benchmark data on the performance of simple, single-layer earthen covers at thee uranium tailings sites. The performance of the covers was evaluated in terms of their reduction of radon gas releases, although moisture profiles and other cover parameters were also monitored. The tests were designed to evaluate the effectiveness of local soils applied with minimum engineering design or compaction effort. The tests, therefore, tend to represent a lowest-cost, and perhaps a worst-case scenario for tailings reclamation. The field benchmark tests are part of a major research program being conducted by the US Department of Energy to develop technology for uranium tailings disposal. The present tests with simple earthen covers thus provide a comparative basis for evaluating the effectiveness of more highly-engineered systems and their proportionately higher costs. These tests were conducted on the inactive tailings piles at Salt Lake City; Mexican Hat, Utah; and Grand Junction, Colorado. The test covers were installed during the summer of 1981 (Ri81) and have been monitored during the following year. This report describes the experimental details of the cover tests, the data that were collected during the one-year monitoring period, and the conclusions that were drawn from the experiments. 5 refs., 5 figs., 13 tabs

Study on the behaviour of high energy electrons in REPUTE-1 ULQ plasmas

International Nuclear Information System (INIS)

Ogawa, Y.; Morikawa, J.; Nihei, H.; Nakajima, T.; Ozawa, D.; Ohno, M.; Suzuki, T.; Himura, H.; Yoshida, Z.; Morita, S.; Shirai, Y.

2001-01-01

In REPUTE-1 Ultra-Low-q (ULQ) plasmas, behaviors of high energy electrons have been studied through a low-Z pellet injection experiment, in addition to the measurements of soft-X ray PHA and Electron Energy Analyzer (EEA). The high energy tail has been measured in the soft-X ray spectrum, and EEA signal has shown a strong anisotropy of the electron distribution function (i.e., the electron flux to the electron drift side is dominant). To study temporal and spatial information on these high energy electrons, a low-Z pellet injection experiment has been conducted. A small piece of plastic pellet is injected from the top of the REPUTE-1 device, and the trajectory of the pellet inside the plasma is measured by CCD camera. We have observed a large deflection of the pellet trajectory to the toroidal direction opposite to the plasma current (i.e., the electron drift side). This suggests that a pellet is ablated selectively only from one side due to the high energy electrons with a large heat flux. We have calculated the heat flux carried by high energy electrons. Since the repulsion force to the pellet can be calculated with the 2 nd derivative of the pellet trajectory, we have estimated the heat flux of high energy electrons to be a few tens MW/m 2 around the plasma center. Experimental data by EEA measurement and low-Z pellet ablation show the large population of the high energy electrons at the core region in comparison with the edge region, suggesting a MHD dynamo mechanism for the production of the high energy electrons. (author)

Tailings management at Nabarlek

International Nuclear Information System (INIS)

Waggitt, P.

1989-01-01

As the entire uranium deposit at Nabarlek was mined in 1979, the mine pit was available as a tailing's repository from the time of commencement of ore processing. In the early years Nabarlek's tailings were deposited subaqueously. In 1985 the tailings deposition method was changed to a sub-aerial, or semi-dry, method. Over the subsequent three years there was evidence that the tailings settled further and squeezed water from lower layers. The water was pumped away and treated for removal of radium before being evaporated in one of the mine's evaporation ponds. When milling was completed in 1988 it was decided to try and increase the rate of water removal and so obtain even greater consolidation of the trailings in a shorter time. This was achieved by loading the tailings with a layer of screened leached sands and waste rock placed on a layer of geotextile filter fabric that had been laid over the whole of the tailings surface in the pit. Once this was completed a modified piling rig was used to insert vertical drains, or wicks, up to 30 metres into the tailings. The drains were placed on a square grid at a spacing of 3.25 metres. Water that was forced out of the tailings by the downward pressure of the sand and rock could flow freely to the surface up these drains. Once at the surface the water was gathered into a sump and pumped away for treatment as before. The drains are working very well at present although it will be some considerable time before the water stops flowing. Already settlement of the tailings is apparent and the settled density of the material is increasing. As far as is known this is the first time that such a system has been employed on mine tailings in a pit in this way

Cameco engineered tailings program: linking applied research with industrial processes for improved tailings performance

International Nuclear Information System (INIS)

Kotzer, T.G.

2010-01-01

'Full text:' Mine tailings at Cameco's operations are by-products of milling uranium ore having variable concentrations of uranium, metals, oxyanions and trace elements or elements of concern (EOC). Cameco has undertaken an Engineered Tailings (ET) program to optimize tailings performance and minimize environmental EOC impacts, regardless of the milled ore source. Applied geochemical and geotechnical tailings research is key within the ET program. In-situ drilling and experimental programs are used to understand long-term tailings behaviour and help validate source term predictions. Within this, the ET program proactively aids in the development of mill-based processes for production of tailings having improved long-term stability. (author)

Heavy tails of OLS

DEFF Research Database (Denmark)

Mikosch, Thomas Valentin; de Vries, Casper

2013-01-01

Suppose the tails of the noise distribution in a regression exhibit power law behavior. Then the distribution of the OLS regression estimator inherits this tail behavior. This is relevant for regressions involving financial data. We derive explicit finite sample expressions for the tail probabili...

In-situ grouting of uranium-mill-tailings piles: an assessment

International Nuclear Information System (INIS)

Tamura, T.; Boegly, W.J. Jr.

1983-05-01

Passage in 1978 of the Uranium Mill Tailings Radiation Control Act (UMTRCA) initiated a program of remedial action for 22 existing mill tailings piles generated in the period 1940 to 1970 as part of the nation's defense and nuclear power programs. The presence of these piles poses potential health and environmental contamination concerns. Possible remedial actions proposed include multilayer covers over the piles to reduce water infiltration, reduce radon gas releases, and reduce airborne transport of tailings fines. In addition, suggested remedial actions include (1) the use of liners to prevent groundwater contamination by leachates from the piles and (2) chemical stabilization of the tailings to retain the radioactive and nonradioactive sources of contamination. Lining of the piles would normally be applicable only to piles that are to be moved from their present location such that the liner could be placed between the tailings and the groundwater. However, by using civil engineering techniques developed for grouting rocks and soils for strength and water control, it may be possible to produce an in situ liner for piles that are not to be relocated. The Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project Office requested that ORNL assess the potential application of grouting as a remedial action. This report examines the types of grouts, the equipment available, and the costs, and assesses the possibility of applying grouting technology as a remedial action alternative for uranium mill tailings piles

In-situ grouting of uranium-mill-tailings piles: an assessment

Energy Technology Data Exchange (ETDEWEB)

Tamura, T.; Boegly, W.J. Jr.

1983-05-01

Passage in 1978 of the Uranium Mill Tailings Radiation Control Act (UMTRCA) initiated a program of remedial action for 22 existing mill tailings piles generated in the period 1940 to 1970 as part of the nation's defense and nuclear power programs. The presence of these piles poses potential health and environmental contamination concerns. Possible remedial actions proposed include multilayer covers over the piles to reduce water infiltration, reduce radon gas releases, and reduce airborne transport of tailings fines. In addition, suggested remedial actions include (1) the use of liners to prevent groundwater contamination by leachates from the piles and (2) chemical stabilization of the tailings to retain the radioactive and nonradioactive sources of contamination. Lining of the piles would normally be applicable only to piles that are to be moved from their present location such that the liner could be placed between the tailings and the groundwater. However, by using civil engineering techniques developed for grouting rocks and soils for strength and water control, it may be possible to produce an in situ liner for piles that are not to be relocated. The Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project Office requested that ORNL assess the potential application of grouting as a remedial action. This report examines the types of grouts, the equipment available, and the costs, and assesses the possibility of applying grouting technology as a remedial action alternative for uranium mill tailings piles.

Study of the high energy emission of accreting compact objects with SPI/INTEGRAL

International Nuclear Information System (INIS)

Droulans, R.

2011-01-01

The study of the high energy emission is essential for understanding the radiative processes inherent to accretion flows onto compact objects (black holes and neutron stars). The X/γ-ray continuum of these systems is successfully interpreted in terms of two components. The first component corresponds to blackbody emission from a geometrically thin optically thick accretion disk while the second component is generally associated to Compton scattering of the thermal disk flux off hot electrons. Despite considerable advances throughout the years, the heating mechanisms as well as the structure of the hot Comptonizing plasma remain poorly understood. In order to shed light on the physical processes that govern the innermost regions of the accretion flow, we take advantage of the data archive accumulated by the SPI instrument, a high energy spectrometer (20 keV - 8 MeV) developed at the CESR (now IRAP, Toulouse, France) for the INTEGRAL mission. Above 150 keV, SPI combines a unique spectral resolution with unequalled sensitivity, being thus an ideal tool to study the high energy emission of accreting compact objects. The thesis manuscript reports on the results of timing and spectral studies of three particular systems. First, I address the high energy emission of the enigmatic micro-quasar GRS 1915+105, a source characterized by colossal luminosity and strong chaotic variability in X-rays. On a timescale of about one day, the photon index of the 20 - 200 keV spectrum varies between 2.7 and 3.5; at higher energies (≥150 keV), SPI unveils the systematic presence of an additional emission component, extending without folding energy up to ∼ 500 keV. Second, I study the high energy emission of GX 339-4, a source whose spectral properties are representative of black hole transients. The spectrum of the luminous hard state of this system shows a variable high energy tail (≥150 keV), with significant flux changes on a short timescale (several hours). I explain the

Uranium Mill Tailings Radiation Control Act of 1978

International Nuclear Information System (INIS)

Magee, J.

1980-01-01

The long-term environmental effects of the Uranium Mill Tailings Radiation Control Act of 1978 address the public health hazards of radioactive wastes and recognize the significance of this issue to public acceptance of nuclear energy. Title I of the Act deals with stabilizing and controlling mill tailings at inactive sites and classifies the sites by priority. It represents a major Federal commitment. Title II changes and strengthens Nuclear Regulatory Commission authority, but it will have little overall impact. It is not possible to assess the Act's effect because there is no way to know if current technology will be adequate for the length of time required. 76 references

Tailings neutralization and other alternatives for immobilizing toxic materials in tailings. Final report

International Nuclear Information System (INIS)

Opitz, B.E.; Sherwood, D.R.; Dodson, M.E.; Serne, R.J.

1985-09-01

This document, ''Tailing Neutralization and Other Alternatives for Immobilizing Toxic Materials in Tailings,'' is the final report in a series of six. It summarizes research completed since the beginning of the project. Three subtasks are included: Subtask A - Neutralization Methods Selection; Subtask B - Laboratory Analysis; and Subtask C - Field Testing. Subtask A reviews treatment processes from other industries to evaluate whether current waste technology from other fields is applicable to the uranium industry. This task also identifies several reagents that were tested for their effectiveness in treating acidic tailings and tailings solution in order to immobilize the contaminants associated with the acid waste. Subtask B describes the laboratory batch and column treatment studies performed on solid waste tailings and tailings solutions over the course of the project. The evaluation of several reagents identified in Subtask A was based on three criteria: (1) treated effluent water quality; (2) neutralized sludge handling and hydraulic properties; and (3) reagent costs and acid neutralizing efficiency. Subtask C presents a field demonstration plan that will evaluate the effectiveness, costs, and benefits of neutralizing acidic uranium mill tailings solution to reduce the potential leaching of toxic trace metals, radionuclides, and macro ions from a tailings impoundment. Details of the related research can be found in the documents listed in the ''Previous Documents in Series.'' 43 refs., 9 figs., 46 tabs

Development in helicopter tail boom strake applications in the US

Science.gov (United States)

Wilson, John C.; Kelley, Henry L.; Donahue, Cynthia C.; Yenni, Kenneth R.

1988-01-01

The use of a strake or spoiler on a helicopter tail boom to beneficially change helicopter tail boom air loads was suggested in the United States in 1975. The anticipated benefits were a change of tail boom loads to reduce required tail rotor thrust and power and improve directional control. High tail boom air loads experienced by the YAH-64 and described in 1978 led to a wind tunnel investigation of the usefullness of strakes in altering such loads on the AH-64, UH-60, and UH-1 helicopters. The wind tunnel tests of 2-D cross sections of the tail boom of each demonstrated that a strake or strakes would be effective. Several limited test programs with the U.S. Army's OH-58A, AH-64, and UH-60A were conducted which showed the effects of strakes were modest for those helicopters. The most recent flight test program, with a Bell 204B, disclosed that for the 204B the tail boom strake or strakes would provide more than a modest improvement in directional control and reduction in tail rotor power.

Critical management issues for the Uranium Mill Tailings Remedial Action (UMTRA) Project

International Nuclear Information System (INIS)

Themelis, J.G.; Krishnan, K.R.

1985-01-01

The Uranium Mill Tailings Radiation Control Act of 1978 (PL95-604) authorized the Secretary of Energy to enter into cooperative agreements with certain states and Indian Tribes to clean up 24 inactive uranium mill tailing sites and associated vicinity properties. The Uranium Mill Tailings Remedial Action (UMTRA) Project includes the three Federal agencies (EPA, DOE, and NRC), eleven state, Indian Tribes, and at least four major contractors. The UMTRA Project extends over a period of ten years. The standards for the Project require a design life of 1000 years with a minimum performance period of 200 years. This paper discusses the critical management issues in dealing with the UMTRA Project and identifies the development of solutions for many of those issues. The highlights to date are promulgation of EPA standards, continued support from Congress and participating states and Indian Tribes, significant leadership shown at all levels, establishment of credibility with the public, and continued motivation of the team. The challenge for tomorrow is making certain NRC will license the sites and maintaining the high level of coordination exhibited to date to assure Project completion on schedule

Lateral movements of a massive tail influence gecko locomotion: an integrative study comparing tail restriction and autotomy.

Science.gov (United States)

Jagnandan, Kevin; Higham, Timothy E

2017-09-07

Tails are an intricate component of the locomotor system for many vertebrates. Leopard geckos (Eublepharis macularius) possess a large tail that is laterally undulated during steady locomotion. However, the tail is readily shed via autotomy, resulting in the loss of tail function, loss in body mass, and a cranial shift in the center of mass. To elucidate the function of tail undulations, we investigated changes in limb kinematics after manipulating the tail artificially by restricting tail undulations and naturally by removing the tail via autotomy. Restricting tail undulations resulted in kinematic adjustments similar to those that occur following tail autotomy, characterized by more flexed hind limb joints. These data suggest that effects of autotomy on locomotion may be linked to the loss of tail movements rather than the loss of mass or a shift in center of mass. We also provide empirical support for the link between lateral tail undulations and step length through the rotation of the pelvic girdle and retraction of the femur. Restriction and autotomy of the tail limits pelvic rotation, which reduces femur retraction and decreases step length. Our findings demonstrate a functional role for tail undulations in geckos, which likely applies to other terrestrial vertebrates.

Assessment of water quality around Jaduguda uranium tailings ponds

International Nuclear Information System (INIS)

Mohanty, A.K.; Gurunadha Rao, V.V.S.; Ramesh, G.; Surinaidu, L.; Thama Rao, G.; Dhakate, R.; Sarangi, A.K.; Nair, R.N.

2010-01-01

The environmental impacts of uranium mining and milling activities are of great concern in many countries for the last three decades. These impacts range from the creation of massive stockpiles of radioactive and toxic waste rock and sand-like tailings to serious contamination of surface and groundwater with radioactive and toxic pollutants, and releases of conventional, toxic and radioactive air pollutants. Uranium mining is also associated with high concentrations of highly toxic heavy metals, which are a major source of surface and groundwater contamination. Depending upon the hydraulic properties of the fractures involved, contaminated ground water may be transported many miles from its point of origin before feeding into an aquifer. Tailings pond may contaminate the groundwater regime by continuous seepage and leaching of radionuclides and other toxic metals due to interaction of rain water through the tailings ponds. The uranium milling and tailings pond operations were started at Jaduguda since 1968. A comprehensive geological and geophysical investigation has been carried out in the Jaduguda watershed covering the tailings ponds to understand the geohydrological characteristics of the region. High resolution electrical resistivity tomography (ERT) surveys have been carried out to delineate the aquifer geometry. Water quality analyses were carried out in three seasons covering from premonsoon to postmonsoon period during 2008-2009. Uranium concentrations have been observed in the dug wells, surface water and monitoring wells

Injurious tail biting in pigs

DEFF Research Database (Denmark)

D'Eath, R.B.; Amott, G.; Turner, S. P.

2014-01-01

not allow tail docking at all. Against this background, using a novel approach focusing on research where tail injuries were quantified, we review the measures that can be used to control tail biting in pigs without tail docking. Using this strict criterion, there was good evidence that manipulable...... substrates and feeder space affect damaging tail biting. Only epidemiological evidence was available for effects of temperature and season, and the effect of stocking density was unclear. Studies suggest that group size has little effect, and the effects of nutrition, disease and breed require further...... underlying processes of tail biting. A quantitative comparison of the efficacy of different methods of provision of manipulable materials, and a review of current practices in countries and assurance schemes where tail docking is banned, both suggest that daily provision of small quantities of destructible...

Lateral movements of a massive tail influence gecko locomotion: an integrative study comparing tail restriction and autotomy

OpenAIRE

Jagnandan, Kevin; Higham, Timothy E.

2017-01-01

Tails are an intricate component of the locomotor system for many vertebrates. Leopard geckos (Eublepharis macularius) possess a large tail that is laterally undulated during steady locomotion. However, the tail is readily shed via autotomy, resulting in the loss of tail function, loss in body mass, and a cranial shift in the center of mass. To elucidate the function of tail undulations, we investigated changes in limb kinematics after manipulating the tail artificially by restricting tail un...

A new model of tail diffusion of phosphorus and boron in silicon

International Nuclear Information System (INIS)

Morehead, F.F.; Lever, R.F.

1986-01-01

It is well known that high surface concentration phosphorus diffusion leads to deeply penetrating tails in its concentration profile. At 700 0 C the tail diffusivity exceeds that of low concentration phosphorus by a factor of a thousand. Less spectacular, but very significant tailing also affects boron, making the conventional models contained in commonly available process simulation programs quite inaccurate for boron diffusions with high surface concentrations. The authors show that the observed tailing can be accounted for by a model whose central assumption is the local equality of dopant and oppositely directed defect fluxes. As predicted by the model, the effect is greatest for normal processing at low temperatures for high surface concentrations. It is minimal for the high temperatures of rapid thermal annealing and unrelated to transient effects

Microscale mineralogical characterization of As, Fe, and Ni in uranium mine tailings

Science.gov (United States)

Essilfie-Dughan, Joseph; Hendry, M. Jim; Warner, Jeff; Kotzer, Tom

2012-11-01

Uranium (U) ores can contain high concentrations of elements of concern (EOCs), such as arsenic (As) and nickel (Ni) present in sulfide and arsenide minerals. The U in these ores is often solubilized by adding H2SO4 to attain a pH ∼1 under oxic conditions. This process releases some EOCs from the primary minerals into solution. The barren raffinate (solution remaining after U extraction) is subsequently neutralized with Ca(OH)2 to a terminal pH of ∼10.5, resulting in a reduction in the aqueous concentrations of the EOCs. These neutralized raffinates are mixed with the non-reacted primary minerals and discharged as tailing into tailings management facilities (TMFs). To aid in the accurate characterization and quantification of the mineralogical controls on the concentrations of EOCs in the tailings porewater, their spatial distribution and speciation were studied at the micron scale in tailings samples collected from the Deilmann U Tailings Management Facility (DTMF), northern Saskatchewan, Canada. Backscattered electron images of the tailings samples generated using an electron microprobe show the presence of nodules (10-200 μm size) surrounded by bright rims. Wavelength dispersive spectrometric (WDS) and synchrotron-based micro-X-ray fluorescence (μ-XRF) elemental mapping show that the nodules are dominated by Ca and S (as gypsum) and the bright rims are dominated by Fe, As, and Ni. Micro-X-ray absorption near-edge structure (μ-XANES) spectra collected within and near the rims indicate that the Fe and Ni are present mainly in the +3 and +2 oxidation states, respectively; for As, the +5 oxidation state dominates but significant amounts of the +3 oxidation state are present in some areas. Linear combination fit analyses of the K-edges for the Fe, As, and Ni μ-XANES spectra to reference compounds suggest the Fe in the rims is present as ferrihydrite with As and Ni are adsorbed to it. Energy dispersive spectrometric (EDS) data indicate that isolated, highly

High-p{sub T} dilepton tails and flavor physics

Energy Technology Data Exchange (ETDEWEB)

Greljo, Admir [Universitaet Zuerich, Physik-Institut, Zuerich (Switzerland); University of Sarajevo, Faculty of Science, Sarajevo (Bosnia and Herzegovina); Marzocca, David [Universitaet Zuerich, Physik-Institut, Zuerich (Switzerland)

2017-08-15

We investigate the impact of flavor-conserving, non-universal quark-lepton contact interactions on the dilepton invariant mass distribution in p p → l{sup +}l{sup -} processes at the LHC. After recasting the recent ATLAS search performed at 13 TeV with 36.1 fb{sup -1} of data, we derive the best up-to-date limits on the full set of 36 chirality-conserving four-fermion operators contributing to the processes and estimate the sensitivity achievable at the HL-LHC. We discuss how these high-p{sub T} measurements can provide complementary information to the low-p{sub T} rare meson decays. In particular, we find that the recent hints on lepton-flavor universality violation in b → sμ{sup +}μ{sup -} transitions are already in mild tension with the dimuon spectrum at high-p{sub T} if the flavor structure follows minimal flavor violation. Even if the mass scale of new physics is well beyond the kinematical reach for on-shell production, the signal in the high-p{sub T} dilepton tail might still be observed, a fact that has been often overlooked in the present literature. In scenarios where new physics couples predominantly to third generation quarks, instead, the HL-LHC phase is necessary in order to provide valuable information. (orig.)

The post-depositional accumulation of metal-rich cyanide phases in submerged tailings deposits

International Nuclear Information System (INIS)

Jambor, J.L.; Martin, A.J.; Gerits, J.

2009-01-01

The characterization and accumulation pathway of metal-rich cyanide phases in mine-contaminated Balmer Lake (Ontario, Canada) were assessed through detailed examination of sediment mineralogy and porewater composition. The near-surface deposits in the lake consist of fine-grained calcareous tailings intermixed with natural organic-rich lake sediments. The tailings contain blue to greenish Fe-dominant cyanide that has formed in situ within the tailings. X-ray diffraction confirmed the presence of a mixed ferri/ferrocyanide [Fe 4 III (Fe II (CN) 6 ) 3 ], commonly referred to as 'Prussian Blue' but it is likely other metal-cyanide complexes are present as evidenced by the distinct colour variations. The cyanide phases occur in up to 1 wt.% as discrete particles and as bedded layers, where the cyanide phases act to cement other siliceous tailings components into a heterogeneous blend. Energy Dispersion X-ray Spectroscopy (EDS) analyses indicate that the authigenic cyanide precipitates contain variable amounts of Ni, Cu and Zn. Quantitatively, the cyanide compounds represent the dominant repository for Cu in Balmer Lake sediments. For Ni and Zn, cyanide associations are secondary in importance to Fe oxyhydroxides. High-resolution porewater profiles and solubility considerations suggest that the formation of the cyanide complexes is a feature of historical (pre-1990) conditions when aqueous cyanide concentrations were higher in the lake.

The post-depositional accumulation of metal-rich cyanide phases in submerged tailings deposits

Energy Technology Data Exchange (ETDEWEB)

Jambor, J.L. [Leslie Research and Consulting, 316 Rosehill Wynd, Tsawwassen, BC, V4M 3L9 (Canada); Martin, A.J., E-mail: ajm@lorax.ca [Lorax Environmental Services, 2289 Burrard St., Vancouver, BC, V6J 3H9 (Canada); Gerits, J. [Lorax Environmental Services, 2289 Burrard St., Vancouver, BC, V6J 3H9 (Canada)

2009-12-15

The characterization and accumulation pathway of metal-rich cyanide phases in mine-contaminated Balmer Lake (Ontario, Canada) were assessed through detailed examination of sediment mineralogy and porewater composition. The near-surface deposits in the lake consist of fine-grained calcareous tailings intermixed with natural organic-rich lake sediments. The tailings contain blue to greenish Fe-dominant cyanide that has formed in situ within the tailings. X-ray diffraction confirmed the presence of a mixed ferri/ferrocyanide [Fe{sub 4}{sup III}(Fe{sup II}(CN){sub 6}){sub 3}], commonly referred to as 'Prussian Blue' but it is likely other metal-cyanide complexes are present as evidenced by the distinct colour variations. The cyanide phases occur in up to 1 wt.% as discrete particles and as bedded layers, where the cyanide phases act to cement other siliceous tailings components into a heterogeneous blend. Energy Dispersion X-ray Spectroscopy (EDS) analyses indicate that the authigenic cyanide precipitates contain variable amounts of Ni, Cu and Zn. Quantitatively, the cyanide compounds represent the dominant repository for Cu in Balmer Lake sediments. For Ni and Zn, cyanide associations are secondary in importance to Fe oxyhydroxides. High-resolution porewater profiles and solubility considerations suggest that the formation of the cyanide complexes is a feature of historical (pre-1990) conditions when aqueous cyanide concentrations were higher in the lake.

Metal removal from tailings ponds water using indigenous micro-algae

Energy Technology Data Exchange (ETDEWEB)

Mahdavi, H.; Ulrich, A.; Liu, Y. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

2010-07-01

Each barrel of oil produced by oil sands produce 1.25 m{sup 3} of tailings. The tailings are collected in ponds located at mining sites. The tailing pond water (TPW) must be reclaimed and released into the environment. This PowerPoint presentation discussed a method of removing metals from tailings pond water that used indigenous micro-algae. The in situ experimental method used Parachlorella kessliri to treat 2 ponds. The TPW was enriched with low and high concentrations of nutrients. Dry cell biomass analyses were then conducted, and the pH of the resulting samples was compared. Inductively coupled plasma mass spectrometry analysis methods were used to determine the initial metal concentrations in the raw TPWs. The study showed that the micro-algae remove significantly more metals when high levels of nutrients are used. tabs., figs.

Performance Comparison between Neutralization Tailings and Flotation Tailings Used for Backfill Mix and Mechanism Analysis

OpenAIRE

Han, Bin; Sun, Wei; Yu, Shaofeng; Liu, Chao; Yao, Song; Wu, Jianxun

2016-01-01

A comparison test of different tailings used for underground backfill was conducted, using neutralized tailings from BIOX and flotation tailings of Jinfeng Mine. Laboratory comparison test results show that, with neutralized tailings, when the cement dosage is at 19%, backfill UCS after 7 days, 14 days, and 28 days are 105%–163%, 80%–102%, and 33%–43%, respectively, which are higher than those of flotation tailings. When the cement dosage is at 12%, backfill UCS after 7 days, 14 days, and 28 ...

NEUTRINO EMISSION FROM HIGH-ENERGY COMPONENT GAMMA-RAY BURSTS

International Nuclear Information System (INIS)

Becker, Julia K.; Olivo, Martino; Halzen, Francis; O Murchadha, Aongus

2010-01-01

Gamma-ray bursts (GRBs) have the potential to produce the particle energies (up to 10 21 eV) and energy budget (10 44 erg yr -1 Mpc -3 ) to accommodate the spectrum of the highest energy cosmic rays; on the other hand, there is no observational evidence that they accelerate hadrons. The Fermi Gamma-ray Space Telescope recently observed two bursts that exhibit a power-law high-energy extension of a typical (Band) photon spectrum that extends to ∼30 GeV. On the basis of fireball phenomenology we argue that these two bursts, along with GRB941017 observed by EGRET in 1994, show indirect evidence for considerable baryon loading. Since the detection of neutrinos is the only unambiguous way to establish that GRBs accelerate protons, we use two methods to estimate the neutrino flux produced when they interact with fireball photons to produce charged pions and neutrinos. While the number of events expected from the two Fermi bursts discussed is small, should GRBs be the sources of the observed cosmic rays, a GRB941017-like event that has a hadronic power-law tail extending to several tens of GeV will be detected by the IceCube neutrino telescope.

Uranium Mill Tailings Remedial Action Project, Surface Project Management Plan. Revision 1

International Nuclear Information System (INIS)

1994-12-01

Title I of the Uranium Mill Tailings Radiation Control Act (UMTRCA) authorizes the US Department of Energy (DOE) to undertake remedial action at 24 designated inactive uranium processing sites and associated vicinity properties (VP) containing uranium mill tailings and related residual radioactive materials. The purpose of the Uranium Mill Tailings Remedial Action (UMTRA) Surface Project is to minimize or eliminate radiation health hazards to the public and the environment at the 24 sites and related VPs. This document describes the management organization, system, and methods used to manage the design, construction, and other activities required to clean up the designated sites and associated VPs, in accordance with the UMTRCA

Uranium Mill Tailings Remedial Action Project, Surface Project Management Plan. Revision 1

Energy Technology Data Exchange (ETDEWEB)

1994-12-01

Title I of the Uranium Mill Tailings Radiation Control Act (UMTRCA) authorizes the US Department of Energy (DOE) to undertake remedial action at 24 designated inactive uranium processing sites and associated vicinity properties (VP) containing uranium mill tailings and related residual radioactive materials. The purpose of the Uranium Mill Tailings Remedial Action (UMTRA) Surface Project is to minimize or eliminate radiation health hazards to the public and the environment at the 24 sites and related VPs. This document describes the management organization, system, and methods used to manage the design, construction, and other activities required to clean up the designated sites and associated VPs, in accordance with the UMTRCA.

Characterization of oils sands thickened tailings

Energy Technology Data Exchange (ETDEWEB)

Scott, J.D.; Jeeravipoolvarn, S.; Donahue, R.; Ozum, B. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

2008-07-01

This presentation discussed the characterization of oils sands thickened tailings. The problem statement was defined as the fact that many laboratory procedures to characterize fine tailings do not take into account the extraction process, and instead use standardized laboratory tests. The purpose of this presentation was to demonstrate how different extraction processes affect the fine tailings geotechnical properties and water chemistry. Properties that were characterized included particle size analysis from hydrometer-sieve tests; per cent clay from methylene blue tests; per cent clay from mineralogy tests; Atterberg limits; water chemistry; and morphology by scanning electron microscopy. The presentation discussed the origin of fines (silt and clay) in tailings; where fine particles come from; tailings materials; mineralogy of tailings; the hydrometer-sieve test on fine tailings and thickened tailings; and the methylene blue test. It was concluded that the great majority of clay minerals in the tailings come from the clay-shale discontinuous seams and layers. For thickened tailings, the dispersed and non-dispersed hydrometer tests show considerable difference in the amount of clay size material. tabs., figs.

Assessing the genetic diversity of Cu resistance in mine tailings through high-throughput recovery of full-length copA genes

Science.gov (United States)

Li, Xiaofang; Zhu, Yong-Guan; Shaban, Babak; Bruxner, Timothy J. C.; Bond, Philip L.; Huang, Longbin

2015-01-01

Characterizing the genetic diversity of microbial copper (Cu) resistance at the community level remains challenging, mainly due to the polymorphism of the core functional gene copA. In this study, a local BLASTN method using a copA database built in this study was developed to recover full-length putative copA sequences from an assembled tailings metagenome; these sequences were then screened for potentially functioning CopA using conserved metal-binding motifs, inferred by evolutionary trace analysis of CopA sequences from known Cu resistant microorganisms. In total, 99 putative copA sequences were recovered from the tailings metagenome, out of which 70 were found with high potential to be functioning in Cu resistance. Phylogenetic analysis of selected copA sequences detected in the tailings metagenome showed that topology of the copA phylogeny is largely congruent with that of the 16S-based phylogeny of the tailings microbial community obtained in our previous study, indicating that the development of copA diversity in the tailings might be mainly through vertical descent with few lateral gene transfer events. The method established here can be used to explore copA (and potentially other metal resistance genes) diversity in any metagenome and has the potential to exhaust the full-length gene sequences for downstream analyses. PMID:26286020

About necessity of remediation and re-cultivation of Taboshar districts' tailings

International Nuclear Information System (INIS)

Salomov, J.A.; Mirsaidov, I.U.; Barotov, A.M.

2012-01-01

Taboshar uranium deposit is one of the oldest sites of uranium industry and reprocessing in former USSR. During geological survey in 1926 close to Istiklol city (former Taboshar), relatively high radioactivity was revealed on present territory and in 1927 the physical exploration of uranium-containing zones was completed. Active extraction of ore was carried out here from 1945 till 1965 y. Nowadays it is a huge territory with total area of more than 400 hectares covered by surface wastes tailings of hydrometallurgical reprocessing of uranium ores. Disposal complex consists from non-preserved open pit ('Factory of barren ores'), destroyed industrial buildings and four tailings (Tailing I-II, Tailing III, Tailing IV and tailing of industrial workshop 3), containing approximately 55 million tons of wastes, from which approximately 12 million tons are uranium ore's wastes. Total area of four tailing and 'Factory of barren ores' is 63 hectares. Besides, balanced-off ores and overburden rocks i.e. ores and rocks unprofitable for reprocessing should be included here as well. Factor analysis of radiation danger carried out by IAEA expert mission in Istiklol city revealed that radon content in air and aerosol contamination is not a factor of considerable radiation risk for city residents, besides cases of their visit to tailings and living of people directly within zones of their location since territory is well aired out. However, due to bad coverage of tailing, drainage waters draining from zones of their location are highly contaminated by radionuclides and contain high concentrations of manganese, sodium, lead and iron. Drainage waters of former flooded uranium mines and open pits are also considerably contaminated. Such contaminated waters are used all over by local population for cattle watering, watering of garden territories and even for drinking. Thus, the use of drainage and mine waters with high contamination level for drinking and

Architecture and environmental restoration: Remediating uranium mill tailings from buildings

International Nuclear Information System (INIS)

Teply, J.D.

1991-01-01

The US Department of Energy (DOE) Grand Junction Projects Office (GJPO) manages the Uranium Mill Tailings Remedial Action (UMTRA) Program in Grand Junction, Colorado. This program is a congressionally mandated clean up of by-product waste that resulted from the extraction of yellow cake from uranium ore. The by-product waste, a fine sand commonly called open-quotes mill tailingclose quotes is contaminated with low-level radioactivity. These mill tailings were available to the community for use as construction material from approximately 1952 to 1966; their use as bedding material for concrete slabs, utilities, backfill materials, concrete sand, and mortar created unique remediation problems that required innovative solutions. This paper describes how design personnel approach the remediation of structures, the evaluation of the buildings, and the factors that must be considered in completing the remediation design. This paper will not address the health risks of the tailings in an inhabited space, the remediation of exterior areas, or the process of determining where the tailings exist in the building

Electro-remediation of copper mine tailings. Comparing copper removal efficiencies for two tailings of different age

DEFF Research Database (Denmark)

Hansen, Henrik K.; Lamas, Victor; Gutierrez, Claudia

2013-01-01

This work compares and evaluates the copper removal efficiency when applying electric fields to two mine tailings originating from the same mine but of different age. Eight experiments were carried out - four on tailings deposited more than 20 years ago (old tailings) and four on tailings deposit...

Uranium mill tailings management

International Nuclear Information System (INIS)

1982-01-01

Facilities for the disposal of uranium mill tailings will invariably be subjected to geomorphological and climatological influences in the long-term. Proceedings of a workshop discuss how the principles of geomorphology can be applied to the siting, design, construction, decommissioning and rehabilitation of disposal facilities in order to provide for long-term containment and stability of tailings. The characteristics of tailings and their behaviour after disposal influence the potential impacts which might occur in the long-term. Proceedings of another workshop examine the technologies for uranium ore processing and tailings conditioning with a view to identifying improvements that could be made in such characteristics

Design and construction of an impoundment for precious metal mill tailings

International Nuclear Information System (INIS)

Moldt, S.F.; Miller, R.G.; Johnson, K.

1985-01-01

An engineering study and design of impoundments for the disposal of mill tailings is presented. The site is located in central Nevada, and the mill will incorporate conventional flotation followed by a carbon-in-pulp cyanide process for extraction of gold from ore. Mill process waste will be generated as flotation tailings and cyanide residue. Permeable site soils and environmental considerations required the prevention of infiltration of cyanide residue leachate into the subgrade. Geochemical modeling of flotation tailings indicated the potential for high concentration of iron and nickel to be present in the flotation tailings leachate. On-site soils were optimized for use in construction of the separate flotation tailings and cyanide residue impoundments. Embankments were constructed on compacted on-site sandy gravels. The cyanide residue impoundment was designed using a four-layer liner, utilizing all on-site soils and chemical soil additives. The liner consists of a leachate collection system over a low-permeability layer, which in turn is underlain by a leak detection drainage blanket and a low permeability subliner. The geochemical modeling performed in the analysis indicated that placement of a thin layer of oxidized surface soils, high in soluble sulfates, on the bottom of the flotation tailings impoundment would be sufficient to react with tailings leachate and cause precipitation of ferric oxide and the associated removal of nickel, permitting flotation tailings leachate to dilute acceptably with natural groundwater

Mine tailings disposal

International Nuclear Information System (INIS)

Gonzales, P.A.; Adams, B.J.

1980-06-01

The hydrologic evaluation of mine tailings disposal sites after they are abandoned is considered in relation to their potential environmental impact on a long term basis. There is a direct relation between the amounts and types of water leaving a disposal site and the severity of the potential damage to the environment. The evaluation of the relative distribution of the precipitation reaching the ground into evaporation, runoff and infiltration is obtained for a selected site and type of tailings material whose characteristics and physical properties were determined in the soils laboratory. A conceptual model of the hydrologic processes involved and the corresponding mathematical model were developed to simulate the physical system. A computer program was written to solve the set of equations forming the mathematical model, considering the physical properties of the tailings and the rainfall data selected. The results indicate that the relative distribution of the precipitation depends on the surface and upper layer of the tailings and that the position of the groundwater table is governed by the flow through the bottom of the profile considered. The slope of the surface of the mass of tailings was found to be one of the principal factors affecting the relative distribution of precipitation and, therefore, the potential pollution of the environment

Utilisation of iron ore tailings as aggregates in concrete

Directory of Open Access Journals (Sweden)

Francis Atta Kuranchie

2015-12-01

Full Text Available Sustainable handling of iron ore tailings is of prime concern to all stakeholders who are into iron ore mining. This study seeks to add value to the tailings by utilising them as a replacement for aggregates in concrete. A concrete mix of grade 40 MPa was prepared in the laboratory with water–cement ratio of 0.5. The concrete were cured for 1, 2, 3, 7, 14 and 28 days. The properties of the concrete such as workability, durability, density, compressive strength and indirect tensile strength were tested. A controlled mix of concrete was also prepared in similar way using conventional materials and the results were compared with the tailings concrete. It was found that the iron ore tailings may be utilised for complete replacement for conventional aggregates in concrete. The iron ore tailings aggregates concrete exhibited a good mechanical strength and even in the case of compressive strength, there was an improvement of 11.56% over conventional aggregates concrete. The indirect tensile strength did not improve against the control mix due high content of fines in the tailings aggregates but showed 4.8% improvement compared with the previous study where the conventional fine aggregates was partially replaced by 20% with iron ore tailings.

THE NARROW X-RAY TAIL AND DOUBLE Hα TAILS OF ESO 137-002 IN A3627

International Nuclear Information System (INIS)

Zhang, B.; Lin, X. B.; Kong, X.; Sun, M.; Ji, L.; Sarazin, C.; Nulsen, P. E. J.; Forman, W.; Jones, C.; Roediger, E.; Donahue, M.; Voit, G. M.

2013-01-01

We present the analysis of a deep Chandra observation of a ∼2 L * late-type galaxy, ESO 137-002, in the closest rich cluster A3627. The Chandra data reveal a long (∼>40 kpc) and narrow tail with a nearly constant width (∼3 kpc) to the southeast of the galaxy, and a leading edge ∼1.5 kpc from the galaxy center on the upstream side of the tail. The tail is most likely caused by the nearly edge-on stripping of ESO 137-002's interstellar medium (ISM) by ram pressure, compared to the nearly face-on stripping of ESO 137-001 discussed in our previous work. Spectral analysis of individual regions along the tail shows that the gas throughout it has a rather constant temperature, ∼1 keV, very close to the temperature of the tails of ESO 137-001, if the same atomic database is used. The derived gas abundance is low (∼0.2 solar with the single-kT model), an indication of the multiphase nature of the gas in the tail. The mass of the X-ray tail is only a small fraction (<5%) of the initial ISM mass of the galaxy, suggesting that the stripping is most likely at an early stage. However, with any of the single-kT, double-kT, and multi-kT models we tried, the tail is always 'over-pressured' relative to the surrounding intracluster medium (ICM), which could be due to the uncertainties in the abundance, thermal versus non-thermal X-ray emission, or magnetic support in the ICM. The Hα data from the Southern Observatory for Astrophysical Research show a ∼21 kpc tail spatially coincident with the X-ray tail, as well as a secondary tail (∼12 kpc long) to the east of the main tail diverging at an angle of ∼23° and starting at a distance of ∼7.5 kpc from the nucleus. At the position of the secondary Hα tail, the X-ray emission is also enhanced at the ∼2σ level. We compare the tails of ESO 137-001 and ESO 137-002, and also compare the tails to simulations. Both the similarities and differences of the tails pose challenges to the simulations. Several implications are

Research on the characterization and conditioning of uranium mill tailings. II. Thermal stabilization of uranium mill tailings: technical and economic evaluation. Volume 2

International Nuclear Information System (INIS)

Dreesen, D.R.; Cokal, E.J.; Thode, E.F.; Wangen, L.E.; Williams, J.M.

1983-06-01

A method of conditioning uranium mill tailings has been devised to greatly reduce radon emanation and contaminant leachability by using high-temperature treatments, i.e., thermal stabilization. The thermally stabilized products appear resistant to weathering as measured by the effects of grinding and water leaching. The technical feasibility of the process has been partially verified in pilot-scale experiments. A conceptual thermal stabilization process has been designed and the economics of the process show that the thermal stabilization of tailings can be cost competitive compared with relocation of tailings during remedial action. The alteration of morphology, structure, and composition during thermal treatment would indicate that this stabilization method may be a long-lasting solution to uranium mill tailings disposal problems

Settlement of uranium mill tailings

International Nuclear Information System (INIS)

Chen, P.K.; Guros, F.B.; Keshian, B.

1988-01-01

Two test embankments were constructed on top of an old tailings deposit near Ambrosia Lake, New Mexico to determine settlement characteristics of hydraulically- deposited uranium mill tailings. Before construction of the embankments, properties of in-situ tailings and foundation soils were determined using data from boreholes, piezocone soundings, and laboratory tests. These properties were used to estimate post-construction settlement of a planned disposal embankment to be constructed on the tailings. However, excessive uncertainty existed in the following: field settlement rates of saturated and unsaturated tailings, degree of preconsolidation of the upper 15 feet of tailings, and the ability of an underlying silty sand foundation layer to facilitate drainage. Thus, assurance could not be provided that differential settlements of the radon barrier and erosion protection layers would be within allowable limits should the planned disposal embankment be constructed in a single-stage

High-energy gamma-rays from Cyg X-1

Science.gov (United States)

Zdziarski, Andrzej A.; Malyshev, Denys; Chernyakova, Maria; Pooley, Guy G.

2017-11-01

We have obtained a firm detection of Cyg X-1 during its hard and intermediate spectral states in the energy range of 40 MeV-60 GeV based on observations by the Fermi Large Area Telescope, confirming the independent results at ≥60 MeV of a previous work. The detection significance is ≃8σ in the 0.1-10 GeV range. In the soft state, we have found only upper limits on the emission at energies ≳0.1 MeV. However, we have found emission with a very soft spectrum in the 40-80 MeV range, not detected previously. This is likely to represent the high-energy cut-off of the high-energy power-law tail observed in the soft state. Similarly, we have detected a γ-ray soft excess in the hard state, which appears to be of similar origin. We have also confirmed the presence of an orbital modulation of the detected emission in the hard state, expected if the γ-rays are from Compton upscattering of stellar blackbody photons. However, the observed modulation is significantly weaker than that predicted if the blackbody upscattering were the dominant source of γ-rays. This argues for a significant contribution from γ-rays produced by the synchrotron self-Compton process. We have found that such strong contribution is possible if the jet is strongly clumped. We reproduce the observed hard-state average broad-band spectrum using a self-consistent jet model, taking into account all the relevant emission processes, e± pair absorption and clumping. This model also reproduces the amplitude of the observed orbital modulation.

Dynamics of Histone Tails within Chromatin

Science.gov (United States)

Bernier, Morgan; North, Justin; Page, Michael; Jaroniec, Christopher; Hammel, Christopher; Poirier, Michael

2012-02-01

Genetic information in humans is encoded within DNA molecules that is wrapped around histone octamer proteins and compacted into a highly conserved structural polymer, chromatin. The physical and material properties of chromatin appear to influence gene expression by altering the accessibility of proteins to the DNA. The tails of the histones are flexible domains that are thought to play a role in regulating DNA accessibility and compaction; however the molecular mechanisms for these phenomena are not understood. I will present CW-EPR studies on site directed spin labeled nucleosomes that probe the structure and dynamics of these histone tails within nucleosomes.

Liner used in tailings ponds

International Nuclear Information System (INIS)

Dinchak, W.G.

1984-01-01

A composite liner has been developed for use in hazardous waste impoundments and in tailings ponds where uranium is involved. The liner offers a high degree of reliability against seepage, is durable, and provides a firm working surface. The advantages of the liner are discussed

Tails, Fears and Risk Premia

DEFF Research Database (Denmark)

Bollerslev, Tim; Todorov, Victor

solely be explained by the level of the volatil- ity. Our empirical investigations are essentially model-free. We estimate the expected values of the tails under the statistical probability measure from "medium" size jumps in high-frequency intraday prices and an extreme value theory approximation...

Tailings transport and deposition downstream of the Northern Hercules (Moline) mine in the catchment of the Mary River, Northern Territory

International Nuclear Information System (INIS)

Cull, R.F.; East, T.J.; Marten, R.; Murray, A.S.; Duggan, K.

1986-01-01

Milling of uraniferous and other metalliferous ores at the Northern Hercules (Moline) Mine near Pine Creek produced some 246,000 tonnes of tailings between 1959 and the closure of the mill in 1972. During this period tailings were contained by several bunds which later failed resulting in the erosion and transport of tailings by tributaries of the Mary River. Suspended sediment concentrations as high as 94 g/L were recorded in Tailings Creek immediately downstream of the eroding tailings pile during the 1984/85 wet season and the total yield was equivalent to a mean erosion rate for the tailings area of 4 mm/yr. This erosion rate is about two orders of magnitude higher than natural rates in the Pine Creek area. Erosion rates of the tailings pile have, however, decreased perhaps by as much as a factor of eight since the last bund was breached. Radioactive dose rates recorded along a series of transects across floodplains downstream of the mill are consistently related to the sedimentary environment. The main channel is associated with low dose rates, and the relatively low energy environments of backswamps and flood bypass channels are characterised by higher dose rates. Longitudinally, dose rates on the floodplain generally decrease with distance downstream although the rate of decrease is not constant, and appears to be dependent upon the hydrological and geomorphic character of the catchment

Research on radon flux reduction from uranium mill tailings

International Nuclear Information System (INIS)

Overmyer, R.F.; Thamer, B.J.; Nielson, K.K.; Rogers, V.C.

1980-01-01

Radon flux reduction from tailings may be accomplished by the use of an impermeable cover to contain the radon until it decays (half life is 2.8 days). The use of a thick, relatively impermeable cover can attenuate radon flux because a large fraction of the radon would decay before it diffuses through the cover into the atmosphere. This method of reducing radon flux may require soil cover thicknesses on the order of 10 feet. In some locations, obtaining 10 feet of soil to cover 200 acres of tailings may be difficult or may lead to other significant environmental impacts. The Department of Energy is sponsoring research to identify alternatives to thick soil covers for reducing radon flux from uranium tailings to meet the forthcoming standards. The two most effective and practical materials tested thus far are Calcilox and asphalt emulsion. Currently, asphalt emulsions are being tested at the Grand Junction tailings pile in Grand Junction, Colorado, by Battelle Pacific Northwest Laboratory. Other asphalt formulations, such as foamed asphalt that requires less water than asphalt emulsions, may be practical and will be tested this year. Some sulfur-based materials and sulfur-extended asphalt also appear promising and will be tested for effectiveness in reducing radon flux. It is also important to investigate methods of applying various stabilizers to inactive tailings piles in various physical conditions of moisture content, and physical stability. Finally, since the EPA standards for remedial action at tailings piles are stated in terms of radon flux, it is important that radon flux measurements be standardized so that reliable flux measurements can be obtained and directly compared among various laboratories

Attitudes of Dutch Pig Farmers Towards Tail Biting and Tail Docking

NARCIS (Netherlands)

Bracke, M.B.M.; Lauwere, de C.C.; Wind, S.M.M.; Zonderland, J.J.

2013-01-01

The Dutch policy objective of a fully sustainable livestock sector without mutilations by 2023 is not compatible with the routine practice of tail docking to minimize the risk of tail biting. To examine farmer attitudes towards docking, a telephone survey was conducted among 487 conventional and 33

Tail-weighted dependence measures with limit being the tail dependence coefficient

KAUST Repository

Lee, David

2017-12-02

For bivariate continuous data, measures of monotonic dependence are based on the rank transformations of the two variables. For bivariate extreme value copulas, there is a family of estimators (Formula presented.), for (Formula presented.), of the extremal coefficient, based on a transform of the absolute difference of the α power of the ranks. In the case of general bivariate copulas, we obtain the probability limit (Formula presented.) of (Formula presented.) as the sample size goes to infinity and show that (i) (Formula presented.) for (Formula presented.) is a measure of central dependence with properties similar to Kendall\\'s tau and Spearman\\'s rank correlation, (ii) (Formula presented.) is a tail-weighted dependence measure for large α, and (iii) the limit as (Formula presented.) is the upper tail dependence coefficient. We obtain asymptotic properties for the rank-based measure (Formula presented.) and estimate tail dependence coefficients through extrapolation on (Formula presented.). A data example illustrates the use of the new dependence measures for tail inference.

Tail-weighted dependence measures with limit being the tail dependence coefficient

KAUST Repository

Lee, David; Joe, Harry; Krupskii, Pavel

2017-01-01

For bivariate continuous data, measures of monotonic dependence are based on the rank transformations of the two variables. For bivariate extreme value copulas, there is a family of estimators (Formula presented.), for (Formula presented.), of the extremal coefficient, based on a transform of the absolute difference of the α power of the ranks. In the case of general bivariate copulas, we obtain the probability limit (Formula presented.) of (Formula presented.) as the sample size goes to infinity and show that (i) (Formula presented.) for (Formula presented.) is a measure of central dependence with properties similar to Kendall's tau and Spearman's rank correlation, (ii) (Formula presented.) is a tail-weighted dependence measure for large α, and (iii) the limit as (Formula presented.) is the upper tail dependence coefficient. We obtain asymptotic properties for the rank-based measure (Formula presented.) and estimate tail dependence coefficients through extrapolation on (Formula presented.). A data example illustrates the use of the new dependence measures for tail inference.

Copper tailings in stucco mortars

Directory of Open Access Journals (Sweden)

Osvaldo Pavez

Full Text Available Abstract This investigation addressed the evaluation of the use of copper tailings in the construction industry in order to reduce the impact on the environment. The evaluation was performed by a technical comparison between stucco mortars prepared with crushed conventional sand and with copper tailings sand. The best results were achieved with the stucco mortars containing tailings. The tailings presented a fine particles size distribution curve different from that suggested by the standard. The values of compressive strength, retentivity, and adherence in the stucco mortars prepared with copper tailings were much higher than those obtained with crushed sand. According to the results from this study, it can be concluded that the preparation of stucco mortars using copper tailings replacing conventional sand is a technically feasible alternative for the construction industry, presenting the benefit of mitigating the impact of disposal to the environment.

Modified binders on the basis of flotation tailings

Science.gov (United States)

Shapovalov, N. A.; Zagorodnyuk, L. Kh; Shchekina, A. Yu; Gorodov, A. I.

2018-03-01

The article proposes compositions of efficient modified composite binders on the basis of portland cement and flotation tailings; the new binders attain the ultimate compressive stress that is twice as high as that of the cement stone. At that, use of annually growing volume of flotation tailings in the production of the composite binder is a rational way for recycling this type of waste and allows saving the planet's natural resources.

Research on Long Tail Recommendation Algorithm

Science.gov (United States)

Hu, Xuezhi; Zhang, Chuang; Wu, Ming; Zeng, Yang

2017-10-01

Most recommendation systems in the major electronic commerce platforms are influenced by the long tail effect more or less. There are sufficient researches of how to assess recommendation effect while no criteria to evaluate long tail recommendation rate. In this study, we first discussed the existing problems of recommending long tail products through specific experiments. Then we proposed a long tail evaluation criteria and compared the performance in long tail recommendation between different models.

Heat Recovery From Tail Gas Incineration To Generate Power

Energy Technology Data Exchange (ETDEWEB)

Tawfik, Tarek

2010-09-15

Many industrial processes result in tail gas wastes that must be flared or incinerated to abide with environmental guidelines. Tail gas incineration occurs in several chemical processes resulting in high-temperature exhaust gas that simply go to the stack, thus wasting all that valuable heat! This paper discusses useful heat recovery and electric power generation utilizing available heat in exhaust gas from tail gas incinerators. This heat will be recovered in a waste-heat recovery boiler that will produce superheated steam to expand in a steam turbine to generate power. A detailed cost estimate is presented.

Radon barrier field-test monitoring at Grand Junction tailings pile

International Nuclear Information System (INIS)

Freeman, H.D.; Hartley, J.N.; Gee, G.W.

1983-11-01

Pacific Northwest Laboratory (PNL), as part of the Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project (UMTRAP) technology development program, has conducted three large-scale field tests of radon covers at the uranium mill tailings pile in Grand Junction, Colorado. The barrier systems, monitored for radon flux for over two years, include earthen, multilayer, and asphalt emulsion covers. Results of the monitoring have shown that a variety of cover systems can meet the Environmental Protection Agency (EPA) standard. The most effective covers tested were asphalt emulsion and earthen (mancos shale). 10 references, 7 figures, 1 table

Groundwater leaching of neutralized and untreated acid-leached uranium-mill tailings

International Nuclear Information System (INIS)

Gee, G.W.; Begej, C.W.; Campbell, A.C.; Sauter, N.N.; Opitz, B.E.; Sherwood, D.R.

1981-01-01

Tailings neutralization was examined to determine the effect of neutralization on contaminant release. Column leaching of acid extracted uranium mill tailings from Exxon Highland Mill, Wyoming, Pathfinder Gas Hills Mill, Wyoming, and the Dawn Midnite Mill, Washington, resulted in the flushing of high concentrations of salts in the first four pore volumes of leachate, followed by a steady decrease to the original groundwater salt concentrations. Neutralization decreased the concentration of salts and radionuclides leaching from the tailings and decreased the volume of solution required to return the solution to the groundwater pH and EC. Radium-226 and uranium-238 leached quickly from the tailings in the initial pore volumes of both neutralized and unneutralized tailings, and then decreased significantly. 6 figures, 5 tables

Tail Asymptotics for the Sum of two Heavy-tailed Dependent Risks

DEFF Research Database (Denmark)

Albrecher, H.; Asmussen, Søren

Let X1,X2 denote positive exchangable heavy-tailed random variables with continuous marginal distribution function F. The asymptotic behavior of the tail of X1 + X2 is studied in a general copula framework and some bounds and extremal properties are provided. For more specific assumptions on F...

Process for Transition of Uranium Mill Tailings Radiation Control Act Title II Disposal Sites to the U.S. Department of Energy Office of Legacy Management for Long-Term Surveillance and Maintenance

Energy Technology Data Exchange (ETDEWEB)

None

2012-03-01

This document presents guidance for implementing the process that the U.S. Department of Energy (DOE) Office of Legacy Management (LM) will use for assuming perpetual responsibility for a closed uranium mill tailings site. The transition process specifically addresses sites regulated under Title II of the Uranium Mill Tailings Radiation Control Act (UMTRCA) but is applicable in principle to the transition of sites under other regulatory structures, such as the Formerly Utilized Sites Remedial Action Program.

Mine tailings composition in a historic site: implications for ecological restoration.

Science.gov (United States)

Courtney, R

2013-02-01

Ecological restoration, using tolerant plant species and nutrient additions, is a low-cost option to decrease environmental risks associated with mine tailings. An attempt was previously made to establish such a vegetation cover on an abandoned tailings facility in Southern Ireland. Historically, the tailings site has been prone to dusting and is a potential source of contamination to the surrounding environment. The site was examined to determine the success of the previous restoration plan used to revegetate the site and to determine its suitability for further restoration. Three distinct floristic areas were identified (grassland, poor grassland and bare area) based on herbage compositions and elemental analysis. Surface and subsurface samples were taken to characterise tailings from within these areas of the tailings site. The pH of bare surface tailings (pH, 2.7) was significantly more acidic (p tailings being hostile to plant growth. Total metal concentrations in tailings were high (c. 10,000 mg kg(-1) for Pb and up to 20,000 mg kg(-1) for Zn). DTPA-extractable Zn and Pb were 16 and 11 % of the total amount, respectively. Metal content in grasses growing on some areas of the tailings were elevated and demonstrated the inability of the tailings to support sustainable plant growth. Due to the inherently hostile characteristics of these areas, future restoration work will employ capping with a barrier layer.

Regulatory principles, criteria and guidelines for site selection, design, construction and operation of uranium tailings retention systems

International Nuclear Information System (INIS)

Coady, J.R.; Henry, L.C.

1978-01-01

Principles, criteria and guidelines developed by the Atomic Energy Control Board for the management of uranium mill tailings are discussed. The application of these concepts is considered in relation to site selection, design and construction, operation and decommissioning of tailings retention facilities

Life cycle cost estimation and environmental valuation of coal mine tailings management

Directory of Open Access Journals (Sweden)

Joni Safaat Adiansyah

2017-01-01

Full Text Available Sustainable mining management is increasingly seen as an important issue in achieving a social license to operate for mining companies. This study describes the life cycle cost (LCC analysis and environmental valuation for several coal mine tailings management scenarios. The economic feasibility of six different options was assessed using the Net Present Value (NPV and Benefit-Cost Analysis (BCA methods. These options were belt press (OPT 1, tailings paste (OPT 2, thickened tailings (OPT 3, and OPT 1 with technology improvement and renewable energy sources (OPT 1A-C. The results revealed that OPT 1A (belt press technology with stack cell flotation was the first preference in terms of LCC while OPT 1C (belt press technology with stack cell flotation and 10% wind energy generated the highest benefits value (BCA compared to the other options. The LCC and BCA components and the volume of GHG emissions were used to determine the best option. Normalization of these three elements resulted in the selection of Option 1C as being the most cost-effective option.

Evaluation of Sulfonate-Based Collectors with Different Hydrophobic Tails for Flotation of Fluorite

Directory of Open Access Journals (Sweden)

Renji Zheng

2018-02-01

Full Text Available This investigation aims to demonstrate the effects of hydrophobic tails on the affinity and relevant flotation response of sulfonate-based collectors for fluorite. For this purpose, a series of alkyl sulfonates with different hydrophobic tails, namely sodium decanesulfonate (C10, sodium dodecylsulfate (C12, sodium hexadecanesulfonate (C16, and sodium dodecylbenzenesulfonate (C12B were applied. The flotation tests showed that C12 and C12B had a better collecting performance than C10 and C16 at pH < 10, and the flotation recovery of fluorite was higher when adopting C12B as a collector compared with C12 with a strong base. The adsorption behaviors of collectors on the fluorite surface were studied through zeta potential, Fourier transform infrared (FTIR, and X-ray photoelectron spectroscopy (XPS analyses. It was found that the affinity of alkyl sulfonates for fluorite was enhanced with the increase of the alkyl chain length from C10 to C16. The existence of phenyl in the hydrophobic tail of sulfonates could improve its activity for fluorite by reducing its surface tension. The abnormal phenomenon C16 with a high affinity for fluorite had a low collecting performance for fluorite mainly due to its overlong alkyl chain, resulting in low solubility in pulp, which restrained its interaction with fluorite. We concluded that C12B was the most applicable collector for fluorite among these reagents due to its high activity, high solubility, and low cost, which was further substantiated by calculating their molecular frontier orbital energy.

A new gamma-ray diagnostic for energetic ion distributions - The Compton tail on the neutron capture line

International Nuclear Information System (INIS)

Vestrand, W.T.

1990-01-01

This paper presents a new radiation diagnostic for assaying the energy spectrum and the angular distribution of energetic ions incident on thick hydrogen-rich thermal targets. This diagnostic compares the number of emergent photons in the narrow neutron capture line at 2.223 MeV to the number of Compton scattered photons that form a low-energy tail on the line. It is shown that the relative strength of the tail can be used as a measure of the hardness of the incident ion-energy spectrum. Application of this diagnostic to solar flare conditions is the main thrust of the work presented here. It is examined how the strength of the Compton tail varies with flare viewing angle and the angular distribution of the flare-accelerated particles. Application to compact X-ray binary systems is also briefly discussed. 39 refs

Runaway tails in magnetized plasmas

Science.gov (United States)

Moghaddam-Taaheri, E.; Vlahos, L.; Rowland, H. L.; Papadopoulos, K.

1985-01-01

The evolution of a runaway tail driven by a dc electric field in a magnetized plasma is analyzed. Depending on the strength of the electric field and the ratio of plasma to gyrofrequency, there are three different regimes in the evolution of the tail. The tail can be (1) stable with electrons accelerated to large parallel velocities, (2) unstable to Cerenkov resonance because of the depletion of the bulk and the formation of a positive slope, (3) unstable to the anomalous Doppler resonance instability driven by the large velocity anisotropy in the tail. Once an instability is triggered (Cerenkov or anomalous Doppler resonance) the tail relaxes into an isotropic distribution. The role of a convection type loss term is also discussed.

TIDAL TAILS OF MINOR MERGERS: STAR FORMATION EFFICIENCY IN THE WESTERN TAIL OF NGC 2782

Energy Technology Data Exchange (ETDEWEB)

Knierman, Karen; Scowen, Paul; Jansen, Rolf A. [School of Earth and Space Exploration, Arizona State University, 550 East Tyler Mall, Room PSF-686 (P.O. Box 871404), Tempe, AZ 85287-1404 (United States); Knezek, Patricia M. [WIYN Consortium, Inc., 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Wehner, Elizabeth, E-mail: karen.knierman@asu.edu, E-mail: paul.scowen@asu.edu, E-mail: rolf.jansen@asu.edu, E-mail: pknezek@noao.edu, E-mail: ewehner@haverford.edu [Department of Astronomy, Haverford College, Haverford, PA 19041 (United States)

2012-04-10

While major mergers and their tidal debris are well studied, they are less common than minor mergers (mass ratios {approx}< 0.3). The peculiar spiral NGC 2782 is the result of a merger between two disk galaxies with a mass ratio of {approx}4: 1 occurring {approx}200 Myr ago. This merger produced a molecular and H I-rich, optically bright eastern tail and an H I-rich, optically faint western tail. Non-detection of CO in the western tail by Braine et al. suggested that star formation had not yet begun to occur in that tidal tail. However, deep H{alpha} narrowband images show evidence of recent star formation in the western tail. Across the entire western tail, we find the global star formation rate per unit area ({Sigma}{sub SFR}) to be several orders of magnitude less than expected from the total gas density. Together with extended FUV+NUV emission from Galaxy Evolution Explorer along the tail, this indicates a low global star formation efficiency in the tidal tail producing lower mass star clusters. The H II region that we observed has a local (few-kiloparsec scale) {Sigma}{sub SFR} from H{alpha} that is less than that expected from the total gas density, which is consistent with other observations of tidal debris. The star formation efficiency of this H II region inferred from the total gas density is low, but normal when inferred from the molecular gas density. These results suggest the presence of a very small, locally dense region in the western tail of NGC 2782 or of a low-metallicity and/or low-pressure star-forming region.

Which is the most preventive measure against tail damage in finisher pigs: tail docking, straw provision or lowered stocking density?

DEFF Research Database (Denmark)

Larsen, Mona Lilian Vestbjerg; Andersen, Heidi Mai-Lis; Pedersen, Lene Juul

2018-01-01

One challenge of intensive pig production is tail damage caused by tail biting, and farmers often decrease the prevalence of tail damage through tail docking. However, tail docking is not an optimal preventive measure against tail damage and thus, it would be preferable to replace it. The aim of ...

Population characteristics of a central Appalachian white tailed deer herd

Science.gov (United States)

Tyler A. Campbell; Benjamin R. Laseter; W. Mark Ford; Karl V. Miller; Karl V. Miller

2005-01-01

Reliable estimates of white-tailed deer (Odocoileus virginianus) population parameters are needed for effective population management. We used radiotelemetrv to compare survival and cause-specific mortality rates between male and female white-tailed deer and present reproductive data for a high-density deer herd in the central Appalachians of West Virginia during...

Fat-tailed sheep in Indonesia; an essential resource for smallholders.

Science.gov (United States)

Udo, Henk Mathijs Johannes; Budisatria, I Gede Suparta

2011-10-01

This paper discusses the historical development of fat-tailed sheep in Indonesia, the dynamics of production systems, production and reproduction performances under farmers' conditions, and roles of sheep in livelihoods. In the eighteenth and nineteenth century, fat-tailed sheep from southwest Asia and Africander sheep from South Africa were introduced. Crossing of fat-tailed sheep with the local thin-tailed sheep produced the Javanese fat-tailed sheep. Main motives for the gradual change-over to fat-tailed sheep have been their potential larger body size and the preference of consumers for their meat. Management systems are changing in response to the intensification of land use. The reproductive performances of fat-tailed sheep are good. Households keep four to six animals, housed close to the family quarters. This results in very high levels of faecal bacteria contamination of drinking water sources. Sheep provide a small income, manure, security and help to accumulate capital. Sheep also play a key role in religious festivities. Farmers hardly profit from the increased demand for the feast of sacrifice; animals are sold mainly when the owners have urgent cash needs. Systematic sheep fattening can contribute to higher economic results, if sufficient family labour and crop residues are available.

Numerical investigation of the late-time Kerr tails

Energy Technology Data Exchange (ETDEWEB)

Racz, Istvan; Toth, Gabor Zs, E-mail: iracz@rmki.kfki.hu, E-mail: tgzs@rmki.kfki.hu [RMKI, H-1121 Budapest, Konkoly Thege Miklos ut 29-33 (Hungary)

2011-10-07

The late-time behavior of a scalar field on fixed Kerr background is examined in a numerical framework incorporating the techniques of conformal compactification and hyperbolic initial value formulation. The applied code is 1+(1+2) as it is based on the use of the spectral method in the angular directions while in the time-radial section fourth order finite differencing, along with the method of lines, is applied. The evolution of various types of stationary and non-stationary pure multipole initial states are investigated. The asymptotic decay rates are determined not only in the domain of outer communication but along the event horizon and at future null infinity as well. The decay rates are found to be different for stationary and non-stationary initial data, and they also depend on the fall off properties of the initial data toward future null infinity. The energy and angular momentum transfers are found to show significantly different behavior in the initial phase of the time evolution. The quasinormal ringing phase and the tail phase are also investigated. In the tail phase, the decay exponents for the energy and angular momentum losses at I{sup +} are found to be smaller than at the horizon which is in accordance with the behavior of the field itself and it means that at late times the energy and angular momentum falling into the black hole become negligible in comparison with the energy and angular momentum radiated toward I{sup +}. The energy and angular momentum balances are used as additional verifications of the reliability of our numerical method.

Numerical investigation of the late-time Kerr tails

International Nuclear Information System (INIS)

Racz, Istvan; Toth, Gabor Zs

2011-01-01

The late-time behavior of a scalar field on fixed Kerr background is examined in a numerical framework incorporating the techniques of conformal compactification and hyperbolic initial value formulation. The applied code is 1+(1+2) as it is based on the use of the spectral method in the angular directions while in the time-radial section fourth order finite differencing, along with the method of lines, is applied. The evolution of various types of stationary and non-stationary pure multipole initial states are investigated. The asymptotic decay rates are determined not only in the domain of outer communication but along the event horizon and at future null infinity as well. The decay rates are found to be different for stationary and non-stationary initial data, and they also depend on the fall off properties of the initial data toward future null infinity. The energy and angular momentum transfers are found to show significantly different behavior in the initial phase of the time evolution. The quasinormal ringing phase and the tail phase are also investigated. In the tail phase, the decay exponents for the energy and angular momentum losses at I + are found to be smaller than at the horizon which is in accordance with the behavior of the field itself and it means that at late times the energy and angular momentum falling into the black hole become negligible in comparison with the energy and angular momentum radiated toward I + . The energy and angular momentum balances are used as additional verifications of the reliability of our numerical method.

A Nonluminescent and Highly Virulent Vibrio harveyi Strain Is Associated with “Bacterial White Tail Disease” of Litopenaeus vannamei Shrimp

Science.gov (United States)

Zhou, Junfang; Fang, Wenhong; Yang, Xianle; Zhou, Shuai; Hu, Linlin; Li, Xincang; Qi, Xinyong; Su, Hang; Xie, Layue

2012-01-01

Recurrent outbreaks of a disease in pond-cultured juvenile and subadult Litopenaeus vannamei shrimp in several districts in China remain an important problem in recent years. The disease was characterized by “white tail” and generally accompanied by mass mortalities. Based on data from the microscopical analyses, PCR detection and 16S rRNA sequencing, a new Vibrio harveyi strain (designated as strain HLB0905) was identified as the etiologic pathogen. The bacterial isolation and challenge tests demonstrated that the HLB0905 strain was nonluminescent but highly virulent. It could cause mass mortality in affected shrimp during a short time period with a low dose of infection. Meanwhile, the histopathological and electron microscopical analysis both showed that the HLB0905 strain could cause severe fiber cell damages and striated muscle necrosis by accumulating in the tail muscle of L. vannamei shrimp, which led the affected shrimp to exhibit white or opaque lesions in the tail. The typical sign was closely similar to that caused by infectious myonecrosis (IMN), white tail disease (WTD) or penaeid white tail disease (PWTD). To differentiate from such diseases as with a sign of “white tail” but of non-bacterial origin, the present disease was named as “bacterial white tail disease (BWTD)”. Present study revealed that, just like IMN and WTD, BWTD could also cause mass mortalities in pond-cultured shrimp. These results suggested that some bacterial strains are changing themselves from secondary to primary pathogens by enhancing their virulence in current shrimp aquaculture system. PMID:22383954

Modelling of contaminant release from a uranium mine tailings site

International Nuclear Information System (INIS)

Kahnt, Rene; Metschies, Thomas

2007-01-01

Available in abstract form only. Full text of publication follows: Uranium mining and milling continuing from the early 1960's until 1990 close to the town of Seelingstaedt in Eastern Germany resulted in 4 tailings impoundments with a total tailings volume of about 105 Mio. m 3 . Leakage from these tailings impoundments enters the underlying aquifers and is discharged into surface water streams. High concentration of salts, uranium and several heavy metals are released from the tailings. At present the tailings impoundments are reshaped and covered. For the identification of suitable remediation options predictions of the contaminant release for different remediation scenarios have to be made. A compartment model representing the tailings impoundments and the surrounding aquifers for the calculation of contaminant release and transport was set up using the software GOLDSIM. This compartment model describes the time dependent hydraulic conditions within the tailings and the surrounding aquifers taking into account hydraulic and geotechnical processes influencing the hydraulic properties of the tailings material. A simple geochemical approach taking into account sorption processes as well as retardation by applying a k d -approach was implemented to describe the contaminant release and transport within the hydraulic system. For uranium as the relevant contaminant the simple approach takes into account additional geochemical conditions influencing the mobility. Alternatively the model approach allows to include the results of detailed geochemical modelling of the individual tailings zones which is than used as source term for the modelling of the contaminant transport in the aquifer and to the receiving streams. (authors)

Uranium mill tailings and radon

International Nuclear Information System (INIS)

Hanchey, L.A.

1981-01-01

The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the US may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action Program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100

Uranium mill tailings and radon

Energy Technology Data Exchange (ETDEWEB)

Hanchey, L A

1981-04-01

The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the United States may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100.

Uranium mill tailings and radon

Energy Technology Data Exchange (ETDEWEB)

Hanchey, L A

1981-01-01

The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the US may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action Program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100.

Characterization of a coal tailing deposit for zero waste mine in the Brazilian coal field of Santa Catarina

International Nuclear Information System (INIS)

Amaral Filho, J.R.; Schneider, I.A.H.; Tubino, R.M.C.; Brum de, I.A.S.; Miltzarek, G.; Sampaio, C.H.

2010-01-01

Coal tailings deposits in Brazil are occupying large areas of land while also generating acid mine drainage (AMD) that includes heavy metals. This paper described an analytical study of a typical coal tailings deposit. The study objective was to separate low density, intermediate density, and high density fractions for future reuse. Particle size analysis, disymmetric studies, X-ray diffraction, and tests conducted to determine ash, total sulphur, and acid bases were conducted in order to characterize the coal tailings samples. Results of the study demonstrated a size distribution of 67 percent coarse, 14 percent fine, and 19 percent ultra-fine particles. The gravimetric concentration method was used to recover 34.2 percent of the total deposit for future energy use. Approximately 9.2 percent of the remaining deposit was a pyrite concentrate. The acid generating potential of the remaining materials was reduced by approximately 60 percent. 9 refs., 1 tab., 2 figs.

Average configuration of the geomagnetic tail

International Nuclear Information System (INIS)

Fairfield, D.H.

1979-01-01

Over 3000 hours of Imp 6 magnetic field data obtained between 20 and 33 R/sub E/ in the geomagnetic tail have been used in a statistical study of the tail configuration. A distribution of 2.5-min averages of B/sub z/ as a function of position across the tail reveals that more flux crosses the equatorial plane near the dawn and dusk flanks (B-bar/sub z/=3.γ) than near midnight (B-bar/sub z/=1.8γ). The tail field projected in the solar magnetospheric equatorial plane deviates from the x axis due to flaring and solar wind aberration by an angle α=-0.9 Y/sub SM/-2.7, where Y/sub SM/ is in earth radii and α is in degrees. After removing these effects, the B/sub y/ component of the tail field is found to depend on interplanetary sector structure. During an 'away' sector the B/sub y/ component of the tail field is on average 0.5γ greater than that during a 'toward' sector, a result that is true in both tail lobes and is independent of location across the tail. This effect means the average field reversal between northern and southern lobes of the tail is more often 178 0 rather than the 180 0 that is generally supposed

Study of Cu and Pb partitioning in mine tailings using the Tessier sequential extraction scheme

Energy Technology Data Exchange (ETDEWEB)

Andrei, Mariana Lucia, E-mail: marianaluciaandrei@yahoo.com [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Babes-Bolyai University, Environmental Science and Engineering Faculty, 30 Fantanele, 400294, Cluj-Napoca (Romania); Senila, Marin; Hoaghia, Maria Alexandra; Levei, Erika-Andrea [INCDO-INOE 2000, Research Institute for Analytical Instrumentation, 67 Donath, 400293, Cluj-Napoca (Romania); Borodi, Gheorghe [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania)

2015-12-23

The Cu and Pb partitioning in nonferrous mine tailings was investigated using the Tessier sequential extraction scheme. The contents of Cu and Pb found in the five operationally defined fractions were determined by inductively coupled plasma optical emission spectrometry. The results showed different partitioning patterns for Cu and Pb in the studied tailings. The total Cu and Pb contents were higher in tailings from Brazesti than in those from Saliste, while the Cu contents in the first two fractions considered as mobile were comparable and the content of mobile Pb was the highest in Brazesti tailings. In the tailings from Saliste about 30% of Cu and 3% of Pb were found in exchangeable fraction, while in those from Brazesti no metals were found in the exchangeable fraction, but the percent of Cu and Pb found in the bound to carbonate fraction were high (20% and 26%, respectively). The highest Pb content was found in the residual fraction in Saliste tailings and in bound to Fe and Mn oxides fraction in Brazesti tailings, while the highest Cu content was found in the fraction bound to organic matter in Saliste tailings and in the residual fraction in Brazesti tailings. In case of tailings of Brazesti medium environmental risk was found both for Pb and Cu, while in case of Saliste tailings low risk for Pb and high risk for Cu were found.

Study of Cu and Pb partitioning in mine tailings using the Tessier sequential extraction scheme

International Nuclear Information System (INIS)

Andrei, Mariana Lucia; Senila, Marin; Hoaghia, Maria Alexandra; Levei, Erika-Andrea; Borodi, Gheorghe

2015-01-01

The Cu and Pb partitioning in nonferrous mine tailings was investigated using the Tessier sequential extraction scheme. The contents of Cu and Pb found in the five operationally defined fractions were determined by inductively coupled plasma optical emission spectrometry. The results showed different partitioning patterns for Cu and Pb in the studied tailings. The total Cu and Pb contents were higher in tailings from Brazesti than in those from Saliste, while the Cu contents in the first two fractions considered as mobile were comparable and the content of mobile Pb was the highest in Brazesti tailings. In the tailings from Saliste about 30% of Cu and 3% of Pb were found in exchangeable fraction, while in those from Brazesti no metals were found in the exchangeable fraction, but the percent of Cu and Pb found in the bound to carbonate fraction were high (20% and 26%, respectively). The highest Pb content was found in the residual fraction in Saliste tailings and in bound to Fe and Mn oxides fraction in Brazesti tailings, while the highest Cu content was found in the fraction bound to organic matter in Saliste tailings and in the residual fraction in Brazesti tailings. In case of tailings of Brazesti medium environmental risk was found both for Pb and Cu, while in case of Saliste tailings low risk for Pb and high risk for Cu were found

Engineering assessment of inactive uranium mill tailings. Canonsburg Site, Canonsburg, Pennsylvania

International Nuclear Information System (INIS)

1982-04-01

Ford, Bacon and Davis Utah Inc. has evaluated the Canonsburg site in order to assess the problems resulting from the existence of radioactive residues at Canonsburg, Pennsylvania. This engineering assessment has included the preparation of topographic maps, radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative remedial actions. Radon gas released from the approximately 300,000 tons of tailings and contaminated soil at the Canonsburg site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The four alternative actions presented in this engineering assessment range from millsite and off-site decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings and contaminated materials to a remote disposal site and decontamination of the Canonsburg site (Options II through IV). Cost estimates for the four options range from $23,244,000 for stabilization in-place, to $27,052,000 for disposal at a distance of about 17 mi. Three principal alternatives for the reprocessing of the Canonsburg tailings were examined: heap leaching; treatment at an existing mill; and reprocessing at a new conventional mill constructed for tailings reprocessing. As required by Public Law 95-604, under whose auspices this project is conducted, the US Department of Energy has solicited expressions of interest in reprocessng the tailings and residues at the Canonsburg site for uranium recovery. Since no such interest was demonstrated, no effort has been made to estimate the value of the residual uranium resource at the Canonsburg site

Signal shaping and tail cancellation for gas proportional detectors at high counting rates

International Nuclear Information System (INIS)

Boie, R.A.; Hrisoho, A.T.; Rehak, P.

1982-01-01

A low noise, wide bandwidth preamplifier and signal processing filter were developed for high counting rate proportional counters. The filter consists of a seven pole Gaussian integrator with symmetrical weighting function and continuously variable shaping time, tausub(s), of 8-50 ns (fwhm) preceded by a second order pole/zero circuit which cancels the long (1/t) tails of the chamber signals. The preamplifier is an optimized common base input design with 2 ns rise time and an equivalent noise input charge < 2000 r.m.s. electrons, when connected to a chamber with 10 pF capacitance and at a filtering time, tausub(s), of 10 ns. (orig.)

Baseline risk assessment of ground water contamination at the uranium mill tailings site Salt Lake City, Utah

Energy Technology Data Exchange (ETDEWEB)

1994-09-01

This baseline risk assessment of groundwater contamination at the uranium mill tailings site near Salt Lake City, Utah, evaluates potential public health or environmental impacts resulting from ground water contamination at the former uranium ore processing site. The tailings and other contaminated material at this site were placed in a disposal cell located at Clive, Utah, in 1987 by the US Department of Energy`s Uranium Mill Tailings Remedial Action (UMTRA) Project. The second phase of the UMTRA Project is to evaluate residual ground water contamination at the former uranium processing site, known as the Vitro processing site. This risk assessment is the first site-specific document under the Ground Water Project. It will help determine the appropriate remedial action for contaminated ground water at the site.

Changes in zinc speciation with mine tailings acidification in a semi-arid weathering environment

OpenAIRE

Hayes, Sarah M.; O’Day, Peggy A.; Webb, Sam M.; Maier, Raina M.; Chorover, Jon

2011-01-01

High concentrations of residual metal contaminants in mine tailings can be transported easily by wind and water, particularly when tailings remain unvegetated for decades following mining cessation, as is the case in semi-arid landscapes. Understanding the speciation and mobility of contaminant metal(loid)s, particularly in surficial tailings, is essential to controlling their phytotoxicities and to revegetating impacted sites. In prior work, we showed that surficial tailings samples from the...

Ecotoxicity of Mine Tailings: Unrehabilitated Versus Rehabilitated.

Science.gov (United States)

Maboeta, M S; Oladipo, O G; Botha, S M

2018-05-01

Earthworms are bioindicators of soil pollution. The ecotoxicity of tailings from selected gold mines in South Africa was investigated utilizing Eisenia andrei bioassays and biomarkers. Samples were obtained from unrehabilitated, rehabilitated and naturally vegetated sites. Biomass, neutral red retention time (NRRT), survival and reproduction were assessed using standardized protocols. Earthworm biomass, NRRT and reproductive success in rehabilitated tailings (comparable to naturally vegetated site) were significantly higher (p tailings. In addition, significantly lower (p tailings compared to the unrehabilitated. Further, significantly lower (p tailings than the rehabilitated and naturally vegetated sites. Overall, reduced ecotoxicity effects were confirmed in rehabilitated compared to unrehabilitated tailings. This suggests that rehabilitation as a post-mining restorative strategy has strong positive influence on mine tailings.

Summary of super high energy events and exotic phenomena in cosmic rays

International Nuclear Information System (INIS)

Miyake, S.

1979-01-01

In this report, the features of superhigh energy events and exotic phenomena are presented. The examples obtained with emulsion chambers show clear trend of change in the hadron interaction characteristics with energy. The scaling law is violated in the very high energy region above 10 15 eV. In the energy region from 10 to 100 TeV, there is mild violation of scaling. The cosmic ray data on the diffusion of high energy particles in the atmosphere was used to study the mild violation of scaling. It is not easy to discuss the violation in the energy region higher than 10 15 eV, because such event can be obtained very rarely. The only method is the observation of extensive air showers. The relation of average transverse momenta to primary cosmic ray energy was compared with some accelerator data. The cosmic ray data tend to show smaller momentum values. The energy spectrum of cosmic ray muons can be measured by the underground observation, the observation of muon-production burst with emulsion chambers, or the observation of horizontal air showers. Analysis of this spectrum shows that there is an upper limit for the direct production of muons at primary energy of several times of 10 14 eV. Other support for the change of interaction character at 10 14 eV is seen. Possible examples of heavy lepton events were found in the deep underground observation. In deep underground observation, anomalous showers with energy content larger than several hundred GeV were observed. Comment on the long tail nuclear cascade is presented. Some experiments for future are introduced. (Kato, T.)

Uranium Mill Tailings Remedial Action Amendments Act of 1988. Introduced in the Senate, One Hundredth Congress, Second Session, Report 100-543, September 23, 1988

International Nuclear Information System (INIS)

Anon.

1988-01-01

The Committee on Energy and Natural Resources reported favorably on the Uranium Mill Tailings Remedial Action Amendments Act of 1987 (S.1991) with some amendments, the principal one being to change the 1987 date to 1988. The purpose of this bill is to authorize the Secretary of the Interior to transfer lands under the jurisdiction of the Bureau of Land Management to the Department of Energy for permanent surveillance and maintenance of remediated mill tailings as required by the Uranium Mill Tailings Radiation Control Act of 1978. The bill also extends the authority of the Secretary of Energy to perform remedial action at designated uranium mill tailings sites and vicinity properties until 30 September 1994. The authority to perform groundwater restoration activities is extended without limitation

Jump Tails, Extreme Dependencies, and the Distribution of Stock Returns

DEFF Research Database (Denmark)

Bollerslev, Tim; Todorov, Viktor

We provide a new framework for estimating the systematic and idiosyncratic jump tail risks in financial asset prices. The theory underlying our estimates are based on in-fill asymptotic arguments for directly identifying the systematic and idiosyncratic jumps, together with conventional long...... market portfolio, we find that the distributions of the systematic and idiosyncratic jumps are both generally heavy-tailed and not necessarily symmetric. Our estimates also point to the existence of strong dependencies between the market-wide jumps and the corresponding systematic jump tails for all...... of the stocks in the sample. We also show how the jump tail dependencies deduced from the high-frequency data together with the day-to-day temporal variation in the volatility are able to explain the “extreme” dependencies vis-a-vis the market portfolio....

ANALYZING FAT-TAILED DISTRIBUTIONS IN EMERGING CAPITAL MARKETS

Directory of Open Access Journals (Sweden)

FELICIA RAMONA BIRĂU

2013-05-01

Full Text Available The aim of this article focuses on analyzing the implications of fat-tailed distributions in emerging capital markets. An essential aspect that was highlighted by most empirical research, especially in terms of emerging capital markets, emphasizes the fact that extreme financial events can not be accurately predicted by the normal distribution. Fat-tailed distributions establish a very effective econometric tool in the analysis of rare events which are characterized by extreme values that occur with a relatively high frequency .The importance of exploring this particular issue derives from the fact that it is fundamental for optimal portfolio selection, derivatives valuation, financial hedging and risk management strategies. The implications of fat-tailed distributions for investment process are significant especially in the turbulent context of the global financial crisis.

Baseline risk assessment of groundwater contamination at the Uranium Mill Tailings Site near Gunnison, Colorado

Energy Technology Data Exchange (ETDEWEB)

1993-12-01

This Baseline Risk Assessment of Groundwater Contamination at the Uranium Mill Tailings Site Near Gunnison, Colorado evaluates potential impacts to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site are being placed in an off-site disposal cell by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This is the second risk assessment of groundwater contamination at this site. The first risk assessment was performed primarily to evaluate existing domestic wells. This risk assessment evaluates the most contaminated monitor wells at the processing site. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site after the tailings are relocated. This risk assessment follows an approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the groundwater are cadmium, cobalt, iron, manganese, sulfate, uranium, and some of the products of radioactive decay of uranium.

Potential of castor bean (Ricinus communis L.) for phytoremediation of mine tailings and oil production.

Science.gov (United States)

Ruiz Olivares, Alejandro; Carrillo-González, Rogelio; González-Chávez, Ma del Carmen A; Soto Hernández, Ramón Marcos

2013-01-15

Bioenergy production combined with phytoremediation has been suggested to help in solving two critical world problems: the gradual reduction of fossil fuels and soil contamination. The aim of this research was to investigate the potential for the use of Ricinus communis L. (castor oil plant) as an energy crop and plant species to remediate metal-polluted sites. This study was performed in mine tailings containing high concentrations of Cu, Zn, Mn, Pb and Cd. Physico-chemical characterization, total, DTPA-extractable and water-soluble metals in rhizospheric tailings heap samples were carried. Metal concentrations in plant tissues and translocation factors (TFs) were also determined. The Ricinus seed-oil content was high between 41 and 64%, seeds from San Francisco site 6 had the highest oil content, while these from site 7 had the lowest. No trend between oil yield vs seed origin site was observed. Seed-oil content was negatively correlated with root concentration of Cu, Zn, Pb and Cd, but no correlation was observed with the extractable-metals. According to its shoot metal concentrations and TFs, castor bean is not a metal accumulator plant. This primary colonizing plant is well suited to cope with the local toxic conditions and can be useful for the stabilization of these residues, and for then decreasing metal bioavailability, dispersion and human health risks on these barren tailings heaps and in the surrounding area. Our work is the first report regarding combined oil production and a phytostabilization role for Ricinus plants in metal mine tailings and may give a new value to suitable metal-polluted areas. Copyright © 2012 Elsevier Ltd. All rights reserved.

INLA goes extreme: Bayesian tail regression for the estimation of high spatio-temporal quantiles

KAUST Repository

Opitz, Thomas

2018-05-25

This work is motivated by the challenge organized for the 10th International Conference on Extreme-Value Analysis (EVA2017) to predict daily precipitation quantiles at the 99.8% level for each month at observed and unobserved locations. Our approach is based on a Bayesian generalized additive modeling framework that is designed to estimate complex trends in marginal extremes over space and time. First, we estimate a high non-stationary threshold using a gamma distribution for precipitation intensities that incorporates spatial and temporal random effects. Then, we use the Bernoulli and generalized Pareto (GP) distributions to model the rate and size of threshold exceedances, respectively, which we also assume to vary in space and time. The latent random effects are modeled additively using Gaussian process priors, which provide high flexibility and interpretability. We develop a penalized complexity (PC) prior specification for the tail index that shrinks the GP model towards the exponential distribution, thus preventing unrealistically heavy tails. Fast and accurate estimation of the posterior distributions is performed thanks to the integrated nested Laplace approximation (INLA). We illustrate this methodology by modeling the daily precipitation data provided by the EVA2017 challenge, which consist of observations from 40 stations in the Netherlands recorded during the period 1972–2016. Capitalizing on INLA’s fast computational capacity and powerful distributed computing resources, we conduct an extensive cross-validation study to select the model parameters that govern the smoothness of trends. Our results clearly outperform simple benchmarks and are comparable to the best-scoring approaches of the other teams.

Effect of the Global Topology of the Interplanetary Magnetic Field on the Properties of Impulsive Acceleration Processes in Distant Regions of the Earth's Magnetospheric Tail

International Nuclear Information System (INIS)

Grigorenko, E.E.; Zelenyi, L.M.; Fedorov, A.O.; Sauvaud, J.-A.

2005-01-01

The paper is devoted to a statistical study of high-speed ion beams (beamlets) observed by the Interball-1 and Interball-2 satellites in the boundary region of the plasma sheet of the geomagnetic tail and in the high-latitude auroral regions of the Earth's magnetosphere. Beamlets result from nonlinear acceleration processes occurring in the current sheet in the distant regions of the geomagnetic tail. They propagate toward the Earth along the magnetic field lines and are detected in the boundary region of the plasma sheet and near the high-latitude boundary of the plasma sheet in the auroral region in the form of short (with a duration of 1-2 min) bursts of high-energy (with energies of about several tens of keV) ions. The sizes of the latitudinal zones where the beamlets are localized in the tail and in the auroral region are determined using the epoch superposition method. The relationship between the frequency of beamlet generation in the boundary region of the plasma sheet and the prehistory of the direction of the interplanetary magnetic field (the magnitude of a clock angle) is investigated. It was established that this direction exerts a global effect on the beamlet generation frequency; moreover, it was found that the beamlet generation frequency in the midnight local time sector of the tail and at the flanks depends differently on the direction of the interplanetary magnetic field. In the midnight sector, the beamlets are observed at almost all directions of the interplanetary field, whereas the frequency of their generation at the flanks is maximal only when the interplanetary magnetic field has a large y component

ESTIMATION OF FILTRATION CAPACITY OF POSTFLOTATION TAILINGS EMBEDDED IN DAMS OF TAILINGS DEPOSITION SITES

Directory of Open Access Journals (Sweden)

Wojciech Tschuschke

2015-10-01

Full Text Available Construction of very big mine tailings deposition sites, such as postflotation tailings ponds, is a complicated engineering task, in which several technical and environmental problems need to be solved. Designing, construction and operation of such an object applying the monitoring method consists in the verification of design assumptions based on continuous observations. One of the primary tasks of monitoring while the deposition site is being filled with tailings is to control quality of the formed dam embankments, as the structural element of the object responsible for its stability. In order to use material selected from deposited tailings in the construction of dams it is necessary to define grain size and compaction criteria, which directly affect load bearing capacity and deformation of the structure. For this reason main control tests include the analyses of grain size distribution and physical properties of the material embedded in the dams. These data may also be used to estimate filtration capacity of the embankment. A lack of drainage, causing accumulation of water within the embankment, may potentially deteriorate stability conditions. This paper presents the use of empirical formulas, i.e. formulas typically applied to natural soils, to assess permeability coefficient of tailings. A simple empirical formula was also proposed for the estimation of permeability coefficient of tailings based on grain size and compaction parameters determined in routine quality tests of constructed dam embankments.

High-energy hadron spin-flip amplitude at small momentum transfer and new AN data from RHIC

International Nuclear Information System (INIS)

Cudell, J.-R.; Selyugin, O.V.; Predazzi, E.

2004-01-01

In the case of elastic high-energy hadron-hadron scattering, the impact of the large-distance contributions on the behaviour of the slopes of the spin-non-flip and of the spin-flip amplitudes is analysed. It is shown that the long tail of the hadronic potential in impact parameter space leads to a value of the slope of the reduced spin-flip amplitude larger than that of the spin-non-flip amplitude. This effect is taken into account in the calculation of the analysing power in proton-nucleus reactions at high energies. It is shown that the preliminary measurement of A N for p 12 C obtained by the E950 Collaboration indeed favours a spin-flip amplitude with a large slope. Predictions for A N at p L =250/ GeV/c are given. (orig.)

Head-on infall of two compact objects: Third post-Newtonian energy flux

International Nuclear Information System (INIS)

Mishra, Chandra Kant; Iyer, Bala R.

2010-01-01

Head-on infall of two compact objects with arbitrary mass ratio is investigated using the multipolar post-Minkowskian approximation method. At the third post-Newtonian order the energy flux, in addition to the instantaneous contributions, also includes hereditary contributions consisting of the gravitational-wave tails, tails-of-tails, and the tail-squared terms. The results are given both for infall from infinity and also for infall from a finite distance. These analytical expressions should be useful for the comparison with the high accuracy numerical relativity results within the limit in which post-Newtonian approximations are valid.

Environmental issues and waste management in energy and minerals production

International Nuclear Information System (INIS)

Yegulalp, T.M.; Kim, K.

1992-01-01

This book includes the following topics: water management in the minerals industry; management of radioactive wastes in the energy industry; the US high-level radioactive waste program; acid mine drainage; health risks from uranium mill tailings; alternate energy sources, such as hydrogen; superconductive magnetic energy storage; nuclear waste

Controlled chaos: three-dimensional kinematics, fiber histochemistry, and muscle contractile dynamics of autotomized lizard tails.

Science.gov (United States)

Higham, Timothy E; Lipsett, Kathryn R; Syme, Douglas A; Russell, Anthony P

2013-01-01

The ability to shed an appendage occurs in both vertebrates and invertebrates, often as a tactic to avoid predation. The tails of lizards, unlike most autotomized body parts of animals, exhibit complex and vigorous movements once disconnected from the body. Despite the near ubiquity of autotomy across groups of lizards and the fact that this is an extraordinary event involving the self-severing of the spinal cord, our understanding of why and how tails move as they do following autotomy is sparse. We herein explore the histochemistry and physiology of the tail muscles of the leopard gecko (Eublepharis macularius), a species that exhibits vigorous and variable tail movements following autotomy. To confirm that the previously studied tail movements of this species are generally representative of geckos and therefore suitable for in-depth muscle studies, we quantified the three-dimensional kinematics of autotomized tails in three additional species. The movements of the tails of all species were generally similar and included jumps, flips, and swings. Our preliminary analyses suggest that some species of gecko exhibit short but high-frequency movements, whereas others exhibit larger-amplitude but lower-frequency movements. We then compared the ATPase and oxidative capacity of muscle fibers and contractile dynamics of isolated muscle bundles from original tails, muscle from regenerate tails, and fast fibers from an upper limb muscle (iliofibularis) of the leopard gecko. Histochemical analysis revealed that more than 90% of the fibers in original and regenerate caudal muscles had high ATPase but possessed a superficial layer of fibers with low ATPase and high oxidative capacity. We found that contraction kinetics, isometric force, work, power output, and the oscillation frequency at which maximum power was generated were lowest in the original tail, followed by the regenerate tail and then the fast fibers of the iliofibularis. Muscle from the original tail exhibited

Reactivity of the isolated perfused rat tail vascular bed

Directory of Open Access Journals (Sweden)

A.S. França

1997-07-01

Full Text Available Isolated segments of the perfused rat tail artery display a high basal tone when compared to other isolated arteries such as the mesenteric and are suitable for the assay of vasopressor agents. However, the perfusion of this artery in the entire tail has not yet been used for functional studies. The main purpose of the present study was to identify some aspects of the vascular reactivity of the rat tail vascular bed and validate this method to measure vascular reactivity. The tail severed from the body was perfused with Krebs solution containing different Ca2+ concentrations at different flow rates. Rats were anesthetized with sodium pentobarbital (65 mg/kg and heparinized (500 U. The tail artery was dissected near the tail insertion, cannulated and perfused with Krebs solution plus 30 µM EDTA at 36oC and 2.5 ml/min and the procedures were started after equilibration of the perfusion pressure. In the first group a dose-response curve to phenylephrine (PE (0.5, 1, 2 and 5 µg, bolus injection was obtained at different flow rates (1.5, 2.5 and 3.5 ml/min. The mean perfusion pressure increased with flow as well as PE vasopressor responses. In a second group the flow was changed (1.5, 2, 2.5, 3 and 3.5 ml/min at different Ca2+ concentrations (0.62, 1.25, 2.5 and 3.75 mM in the Krebs solution. Increasing Ca2+ concentrations did not alter the flow-pressure relationship. In the third group a similar protocol was performed but the rat tail vascular bed was perfused with Krebs solution containing PE (0.1 µg/ml. There was an enhancement of the effect of PE with increasing external Ca2+ and flow. PE vasopressor responses increased after endothelial damage with air and CHAPS, suggesting an endothelial modulation of the tone of the rat tail vascular bed. These experiments validate the perfusion of the rat tail vascular bed as a method to investigate vascular reactivity

Determination of the reaction rate coefficient of sulphide mine tailings deposited under water.

Science.gov (United States)

Awoh, Akué Sylvette; Mbonimpa, Mamert; Bussière, Bruno

2013-10-15

The efficiency of a water cover to limit dissolved oxygen (DO) availability to underlying acid-generating mine tailings can be assessed by calculating the DO flux at the tailings-water interface. Fick's equations, which are generally used to calculate this flux, require knowing the effective DO diffusion coefficient (Dw) and the reaction (consumption) rate coefficient (Kr) of the tailings, or the DO concentration profile. Whereas Dw can be accurately estimated, few studies have measured the parameter Kr for submerged sulphide tailings. The objective of this study was to determine Kr for underwater sulphide tailings in a laboratory experiment. Samples of sulphide mine tailings (an approximately 6 cm layer) were placed in a cell under a water cover (approximately 2 cm) maintained at constant DO concentration. Two tailings were studied: TA1 with high sulphide content (83% pyrite) and TA2 with low sulphide content (2.8% pyrite). DO concentration was measured with a microelectrode at various depths above and below the tailings-water interface at 1 mm intervals. Results indicate that steady-state condition was rapidly attained. As expected, a diffusive boundary layer (DBL) was observed in all cases. An iterative back-calculation process using the numerical code POLLUTEv6 and taking the DBL into account provided the Kr values used to match calculated and experimental concentration profiles. Kr obtained for tailings TA1 and TA2 was about 80 d(-1) and 6.5 d(-1), respectively. For comparison purposes, Kr obtained from cell tests on tailings TA1 was lower than Kr calculated from the sulphate production rate obtained from shake-flask tests. Steady-state DO flux at the water-tailings interface was then calculated with POLLUTEv6 using tailings characteristics Dw and Kr. For the tested conditions, DO flux ranged from 608 to 758 mg O2/m(2)/d for tailings TA1 and from 177 to 221 mg O2/m(2)/d for tailings TA2. The impact of placing a protective layer of inert material over

Markov Tail Chains

OpenAIRE

janssen, Anja; Segers, Johan

2013-01-01

The extremes of a univariate Markov chain with regularly varying stationary marginal distribution and asymptotically linear behavior are known to exhibit a multiplicative random walk structure called the tail chain. In this paper we extend this fact to Markov chains with multivariate regularly varying marginal distributions in Rd. We analyze both the forward and the backward tail process and show that they mutually determine each other through a kind of adjoint relation. In ...

Diagnostic analysis of electrodialysis in mine tailing materials

DEFF Research Database (Denmark)

Hansen, Henrik K.; Ribeiro, Alexandra B.; Mateus, Eduardo

2007-01-01

Removal of heavy metals from mine tailings and soil contaminated by copper mining activities was studied under batch electrodialytic conditions. Two types of mine tailings were treated: (i) freshly produced tailings coming directly from the flotation process, and (ii) tailings deposited...... in a tailings pond, for approximately 20 years. The main contaminant was copper-found in concentration around 800-1800 ppm. The fractionation of copper and other characteristics of the tailings differ for the two tailings, indicating natural oxidation reactions in the old deposited ones. Electrodialytical...

Tales of island tails

NARCIS (Netherlands)

Groot, de Alma V.; Oost, Albert P.; Veeneklaas, Roos M.; Lammerts, Evert Jan; Duin, van Willem E.; Wesenbeeck, van Bregje K.

2016-01-01

The Frisian islands (Southern North Sea) have extensive island tails, i.e. the entire downdrift side of an island consisting of salt marshes, dunes, beaches and beach plains, and green beaches. Currently, large parts of these tails are ageing and losing dynamics, partly due to human influence.

The use of geochemical barriers for reducing contaminants emanating from uranium mill tailings

International Nuclear Information System (INIS)

Groffman, A.R.; Longmire, P.; Mukhopadhyay, B.; Downs, W.

1991-01-01

A problem facing the Department of Energy's Uranium Mill Tailings Remediation Action (UMTRA) Project is the contamination of local ground water by leachate emanating form the tailings piles. These fluids have a low pH and contain heavy metals and trace elements such as arsenic, molybdenum, nitrate, selenium, and uranium. In order to meet ground water standards low hydraulic conductivity covers are installed over the tailings embankment. in some cases it may be necessary to install a geochemical barrier down gradient from the tailings embankment in order to remove the hazardous constituents. By using geochemical barriers to reduce undesirable species form a contaminant plume, fluids emanating form beneath a repository can in effect be scrubbed before entering the water table. Materials containing adsorbing clays, iron oxyhydroxides and zeolites, and reducing materials such as coal and peat, are being used effectively to attenuate contaminants form uranium mill tailings. Experiments to directly determine attenuation capacities of selected buffer/adsorption materials were conducted in the laboratory. Batch leach tests were conducted in lieu of column tests when the hydraulic conductivity of materials was too low to use in columns and shales

Tail docking in pigs: a review on its short- and long-term consequences and effectiveness in preventing tail biting

Directory of Open Access Journals (Sweden)

Eleonora Nannoni

2014-02-01

Full Text Available In spite of European legislation attempting to limit this practice, tail docking is nowadays the only preventive measure against tail biting which is widely adopted by farmers. Docking consists in amputating, usually without anaesthesia or analgesia, the distal part of the tail, in order to reduce its attractiveness and to sensitize it, increasing avoidance behaviour in the bitten pig. Tail docking results in both acute and chronic effects on pig welfare, and its effectiveness in preventing tail biting is limited, since it reduces the symptoms of a behavioural disorder, but does not address the underlying causes. The aim of the present paper is to review the available literature on the effects of tail docking on swine welfare. Although from a practical standpoint the welfare risks arising from tail docking may appear to be negligible compared to those arising during and after tail biting outbreaks, it should be considered that, apart from acute physiological and behavioural responses, tail docking may also elicit long-term effects on weight gain, tail stump sensitivity and animal freedom to express their normal behaviour. Such chronic effects have been poorly investigated so far. Besides, studies evaluating the effectiveness of anaesthetics or analgesic treatments are often conflicting. Within this framework, further research is recommended in order to reduce the acute and chronic pain and discomfort experienced by the animals, until preventive measures (e.g., environmental enrichment, stocking densities are broadly adopted to prevent tail biting.

Cost of implementing AECB interim criteria for the closeout of uranium tailings sites

International Nuclear Information System (INIS)

1981-04-01

The main purpose of this study was to arrive at a gross approximation of the costs to the Canadian uranium mining industry of meeting the proposed closeout criteria established by the Atomic Energy Control Board for tailings deposits. Two options have been investigated: on-land disposal and underlake disposal. Given the budget allocated to the study, the estimates must be understood as approximations. Overall cost figures for the Canadian uranium mining industry are linear extensions from a hypothetical base case. The results of a conference held in Ottawa on February 25 and 26 to discuss the proposed AECB interim criteria for the closeout of uranium tailings sites are also included. Representatives from mining firms, provincial regulatory authorities, universities and the Atomic Energy Control board attended the conference

Meeting the challenge - solutions for managing oil sands tailings: report of the fine tailings fundamentals consortium 1989-1995

International Nuclear Information System (INIS)

1996-01-01

The development and demonstration of effective alternatives for the management of fine tailings in the oil sands industry were discussed in a report describing the work of the Fine Tailings Fundamentals Consortium during the period from 1989 to 1995. The final report of the Consortium is a four-volume publication entitled 'Advances in Oil Sands Tailings Research' which is the state-of-the-art reference to key issues in the reclamation of fine tailings. Government regulations now make it the responsibility of industry to integrate the fine tailings into reclaimed landscapes, so that the final landscape is equal in productive capability to the pre-disturbed state. Impressive progress has been made in understanding the formation of fine tailings and in characterizing their properties, much of it through the work of this Consortium. Fundamental research on the clay particles within fine tailings provides a better understanding of how to manage them. Although there is no 'magic bullet', research has demonstrated that an integrated approach incorporating fine tailings with a variety of elements, uplands, lakes and wetlands, offer the best hope for an environmentally sound solution. figs

The Tail of BPM

Science.gov (United States)

Kruba, Steve; Meyer, Jim

Business process management suites (BPMS's) represent one of the fastest growing segments in the software industry as organizations automate their key business processes. As this market matures, it is interesting to compare it to Chris Anderson's 'Long Tail.' Although the 2004 "Long Tail" article in Wired magazine was primarily about the media and entertainment industries, it has since been applied (and perhaps misapplied) to other markets. Analysts describe a "Tail of BPM" market that is, perhaps, several times larger than the traditional BPMS product market. This paper will draw comparisons between the concepts in Anderson's article (and subsequent book) and the BPM solutions market.

Retreatment of radioactive gold bearing tailings and rehabilitation of mill and tailings dump sites at Rockhole and Moline, Northern Territory

International Nuclear Information System (INIS)

Bastias, J.G.

1987-01-01

A number of uranium mines were operated during the fifties and sixties by mining companies, on behalf of the Commonwealth Government, in the Northern Territory, including the Alligator Rivers Region. As no legislation requiring rehabilitation of mines existed at that time, mining works, tailings dumps and mill facilities were just abandoned at the end of operations. Since Self-Government in 1978, the Northern Territory Government, through the Department of Mines and Energy, has been involved in studies leading to the rehabilitation of these abandoned uranium operations with funds provided by the Commonwealth. The first and most extensive example of this type of rehabilitation was the Rum Jungle Project which was completed in June 1986 at a cost of $18.2 million. The sites of the Rockhole and Moline mills and tailings dumps, worked between 1959 and 1972, are also uranium operations considered for rehabilitation by the Northern Territory Government

Effects of Tail Clipping on Larval Performance and Tail Regeneration Rates in the Near Eastern Fire Salamander, Salamandra infraimmaculata.

Directory of Open Access Journals (Sweden)

Ori Segev

Full Text Available Tail-tip clipping is a common technique for collecting tissue samples from amphibian larvae and adults. Surprisingly, studies of this invasive sampling procedure or of natural tail clipping--i.e., bites inflicted by predators including conspecifics--on the performance and fitness of aquatic larval stages of urodeles are scarce. We conducted two studies in which we assessed the effects of posterior tail clipping (~30 percent of tail on Near Eastern fire salamander (Salamandra infraimmaculata larvae. In a laboratory study, we checked regeneration rates of posterior tail-tip clipping at different ages. Regeneration rates were hump-shaped, peaking at the age of ~30 days and then decreasing. This variation in tail regeneration rates suggests tradeoffs in resource allocation between regeneration and somatic growth during early and advanced development. In an outdoor artificial pond experiment, under constant larval densities, we assessed how tail clipping of newborn larvae affects survival to, time to, and size at metamorphosis. Repeated measures ANOVA on mean larval survival per pond revealed no effect of tail clipping. Tail clipping had correspondingly no effect on larval growth and development expressed in size (mass and snout-vent length at, and time to, metamorphosis. We conclude that despite the given variation in tail regeneration rates throughout larval ontogeny, clipping of 30% percent of the posterior tail area seems to have no adverse effects on larval fitness and survival. We suggest that future use of this imperative tool for the study of amphibian should take into account larval developmental stage during the time of application and not just the relative size of the clipped tail sample.

Baseline risk assessment for groundwater contamination at the uranium mill tailings site near Monument Valley, Arizona

International Nuclear Information System (INIS)

1993-09-01

This baseline risk assessment evaluates potential impact to public health or the environment resulting from groundwater contamination at the former uranium mill processing site near Monument Valley, Arizona. The tailings and other contaminated material at this site are being relocated and stabilized in a disposal cell at Mexican Hat, Utah, through the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. The tailings removal is planned for completion by spring 1994. After the tailings are removed, groundwater contamination at the site will continue to be evaluated. This risk assessment is the first document specific to this site for the Groundwater Project. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site

Characterization and dewatering of flotation technological tailings

Directory of Open Access Journals (Sweden)

Grigorova I.

2014-01-01

Full Text Available The treatment of flotation tailings is today a subject of interest in mineral processing because of the potential of wasted materials as an actual mineral resource and because of environmental reasons. Decantation ponds are found at almost every mine in the world. They are large earth fill dams containing the residue of the milling process to extract metals from mined ores. Traditional wet tailings disposal has been problematic due to the risk of ground water contamination and the difficulty in rehabilitating storage sites. Tailings dams are at risk of failure due to leakage, instability, liquefaction, and poor design. In the last few years the use of paste technology in the disposal of mine tailings is increasingly studied as an option to conventional tailings dams. The Lucky Invest Concentrator is located in the Eastern Rhodopes Mountain of Bulgaria. Since 1959 lead-zinc ores are dressed. Finally, during the flotation cycle lead and zinc concentrates are produced. The final technological processing waste precipitates in tailing pond. Research and development program has started to established opportunities to obtain dry deposit of the ore processing residue and analyses the feature of new tailing disposal method. The tailings particle size distributions and chemical compositions were determined. The data from laboratory and pilot scale tests clearly illustrate that there are the possibilities to obtaine lead-zinc dewatered tailings. The experimental results show that new cyclone modifications have a potential in dewatering technology of flotation tailings. It appears that dewatering cyclones can be an approach on new tailings pond elimination technology.

Uranium mill tailings stabilization

International Nuclear Information System (INIS)

Hartley, J.N.; Koehmstedt, P.L.; Esterl, D.J.; Freeman, H.D.

1980-02-01

Uranium mill tailings pose a potential radiation health hazard to the public. Therefore, stabilization or disposal of these tailings in a safe and environmentally sound way is needed to minimize radon exhalation and other environmental hazards. One of the most promising concepts for stabilizing U tailings is the use of asphalt emulsion to contain radon and other hazardous materials within uranium tailings. This approach is being investigated at the Pacific Northwest Laboratory. Results of these studies indicate that a radon flux reduction of greater than 99% can be obtained using either a poured-on/sprayed-on seal (3.0 to 7.0 mm thick) or an admixture seal (2.5 to 12.7 cm thick) containing about 18 wt % residual asphalt. A field test was carried out in June 1979 at the Grand Junction tailings pile in order to demonstrate the sealing process. A reduction in radon flux ranging from 4.5 to greater than 99% (76% average) was achieved using a 15.2-cm (6-in.) admix seal with a sprayed-on top coat. A hydrostatic stabilizer was used to apply the admix. Following compaction, a spray coat seal was applied over the admix as the final step in construction of a radon seal. Overburden was applied to provide a protective soil layer over the seal. Included in part of the overburden was a herbicide to prevent root penetration

Liquefaction of uranium tailings

International Nuclear Information System (INIS)

1992-02-01

Numerical methods for assessing the liquefaction potential of soils are reviewed with a view to their application to uranium tailings. The method can be divided into two categories: total stress analysis, where changes in pore pressure are not considered in the soil model, and effective stress analysis, where changes in pore pressure are included in the soil model. Effective stress analysis is more realistic, but few computer programs exist for such analysis in two or three dimensions. A simple linearized, two-dimensional, finite element effective stress analysis which incorporates volumetric compaction due to shear motion is described and implemented. The new program is applied to the assessment of liquefaction potential of tailings in the Quirke Mine tailings area near Elliot Lake, Ontario. The results are compared with those of a total stress analysis. Both analyses indicate liquefaction would occur if a magnitude 6.0 earthquake were to occur near the area. However, the extent of liquefaction predicted by the effective stress analysis is much less than that predicted by the total stress analysis. The results of both methods are sensitive to assumed material properties and to the method used to determine the cyclic shear strength of the tailings. Further analysis, incorporating more in situ and/or laboratory data, is recommended before conclusions can be made concerning the dynamic stability of these tailings

Numerical modelling for stability of tailings dams

OpenAIRE

Auchar, Muhammad; Mattsson, Hans; Knutsson, Sven

2013-01-01

A tailings dam is a large embankment structure that is constructed to store the waste from the mining industry. Stability problems may occur in a tailings dam due to factors such as quick rate of raising, internal erosion and liquefaction. The failure of a tailings dam may cause loss of human life and environmental degradation. Tailings Dams must not only be stable during the time the tailings storage facility is in operation, but also long time after the mine is closed. In Sweden, the licens...

Preparation of polymeric aluminium ferric chloride from bauxite tailings

Directory of Open Access Journals (Sweden)

Ma D.

2013-01-01

Full Text Available Bauxite tailings are the main solid wastes in the ore dressing process. The Al2O3 and Fe2O3 contents in bauxite tailings can reach 50% and 13% respectively. The present study proposed a feasible method to use bauxite tailings to prepare polymeric aluminium ferric chloride (PAFC, a new composite inorganic polymer for water purification. Bauxite tailings roasted reacting with hydrochloric acid under air, pickle liquor which mainly contains Fe3+, Al3+ was generated, then calcium aluminate was used to adjust pH value and the basicity of the pickle liquor, the PAFC was subsequently prepared after the polymerization process. The optimal synthesizing parameters for the preparation of PAFC obtained were as follows: the concentration of hydrochloric acid of 24 wt%, ratio of hydrochloric acid to bauxite tailings of 6:1, temperature of 90ºC, leaching time of 2.5 hours, ration of pickle liquor to calcium aluminate of 12:1, polymerization temperature of 90ºC and polymerization time of about 3 hours. The basicity of PAFC was higher than 68%, the sum concentration of Al2O3 and Fe2O3 was beyond 12.5%. The results of flocculation tests indicate that the PAFC has a better performance of removing the turbidity of wastewater compared to PAC, and PAFC prepared by bauxite tailings is a kind of high quality flocculants.

The regenerated tail of juvenile leopard geckos (Gekkota: Eublepharidae: Eublepharis macularius) preferentially stores more fat than the original.

Science.gov (United States)

Russell, Anthony P; Lynn, Sabrina E; Powell, G Lawrence; Cottle, Andrew

2015-06-01

The tail of many species of lizard is used as a site of fat storage, and caudal autotomy is a widespread phenomenon among lizards. This means that caudal fat stores are at risk of being lost if the tail is autotomized. For fat-tailed species, such as the leopard gecko, this may be particularly costly. Previous work has shown that tail regeneration in juveniles of this species is rapid and that it receives priority for energy allocation, even when dietary resources are markedly reduced. We found that the regenerated tails of juvenile leopard geckos are more massive than their original counterparts, regardless of dietary intake, and that they exhibit greater amounts of skeleton, inner fat, muscle and subcutaneous fat than original tails (as assessed through cross-sectional area measurements of positionally equivalent stations along the tail). Autotomy and regeneration result in changes in tail shape, mass and the pattern of tissue distribution within the tail. The regenerated tail exhibits enhanced fat storage capacity, even in the face of a diet that results in significant slowing of body growth. Body growth is thus sacrificed at the expense of rapid tail growth. Fat stores laid down rapidly in the regenerating tail may later be used to fuel body growth or reproductive investment. The regenerated tail thus seems to have adaptive roles of its own, and provides a potential vehicle for studying trade-offs that relate to life history strategy. Copyright © 2015 Elsevier GmbH. All rights reserved.

Uranium mill tailings remedial action project real estate management plan

Energy Technology Data Exchange (ETDEWEB)

1994-09-01

This plan summarizes the real estate requirements of the US Department of Energy`s (DOE) Uranium Mill Tailings Action (UMTRA) Project, identifies the roles and responsibilities of project participants involved in real estate activities, and describes the approaches used for completing these requirements. This document is intended to serve as a practical guide for all project participants. It is intended to be consistent with all formal agreements, but if a conflict is identified, the formal agreements will take precedence.

Does cortical bone thickness in the last sacral vertebra differ among tail types in primates?

Science.gov (United States)

Nishimura, Abigail C; Russo, Gabrielle A

2017-04-01

The external morphology of the sacrum is demonstrably informative regarding tail type (i.e., tail presence/absence, length, and prehensility) in living and extinct primates. However, little research has focused on the relationship between tail type and internal sacral morphology, a potentially important source of functional information when fossil sacra are incomplete. Here, we determine if cortical bone cross-sectional thickness of the last sacral vertebral body differs among tail types in extant primates and can be used to reconstruct tail types in extinct primates. Cortical bone cross-sectional thickness in the last sacral vertebral body was measured from high-resolution CT scans belonging to 20 extant primate species (N = 72) assigned to tail type categories ("tailless," "nonprehensile short-tailed," "nonprehensile long-tailed," and "prehensile-tailed"). The extant dataset was then used to reconstruct the tail types for four extinct primate species. Tailless primates had significantly thinner cortical bone than tail-bearing primates. Nonprehensile short-tailed primates had significantly thinner cortical bone than nonprehensile long-tailed primates. Cortical bone cross-sectional thickness did not distinguish between prehensile-tailed and nonprehensile long-tailed taxa. Results are strongly influenced by phylogeny. Corroborating previous studies, Epipliopithecus vindobonensis was reconstructed as tailless, Archaeolemur edwardsi as long-tailed, Megaladapis grandidieri as nonprehensile short-tailed, and Palaeopropithecus kelyus as nonprehensile short-tailed or tailless. Results indicate that, in the context of phylogenetic clade, measures of cortical bone cross-sectional thickness can be used to allocate extinct primate species to tail type categories. © 2017 Wiley Periodicals, Inc.

Multichannel thickener of flotation tailings

Energy Technology Data Exchange (ETDEWEB)

Kondratenko, A F; Shuliko, A N; Zinchenko, A F

1983-04-01

A multichannel thickener of flotation tailings developed by Ukrniiugleobogashchenie is described. Tailings with solid content ranging from 40 to 60 g/l are mixed with flocculation reagents (quantity ratio from 60 to 70 g/l) in a turbulent mixer: waste water with tailings fed to the mixer is divided into three streams, flocculation reagents are batched in stages with each water stream. After turbulent mixing, water, tailings and reagent are fed to the settling chamber. Settling chamber (dimensions 2.4 x 1.5 x 1.0 m) is divided into a number of channels by settling surfaces of 0.35 m/sup 2/ each, inclined at an angle of 55 degrees. Distance between the surfaces is 50 mm. The thickener has a total settling surface of 18.7 m/sup 2/. Water with tailings flows upwards, cleaned water is removed by a separating system and settled tailings move downward and accumulate in the compacting chamber (dimensions 1.5 x 1.5 x 0.9 m). From the compacting chamber thickened slurry with solid content from 90 to 150 g/l is removed by a hydraulic system. During performance testing in some plants preparing coal difficult to wash, thickening efficiency amounted to 100%. The results of performance testing are shown in two tables. Factors which influence thickener productivity are evaluated. (In Russian)

Uranium Mill Tailings Remedial Action Project Vicinity Property Program

International Nuclear Information System (INIS)

Little, L.E.; Potter, R.F.; Arpke, P.W.

1988-01-01

The Department of Energy Uranium Mill Tailings Remedial Action (UMTRA) Grand Junction Project Vicinity Property Program is a $165 million program for the removal and disposal of uranium mill tailings that were used in the construction of approximately 4,000 residences, commercial buildings, and institutional facilities in the City of Grand Junction and surrounding Mesa County, Colorado. This paper discusses the UMTRA Vicinity Property Program and the economic benefits of this program for the City of Grand Junction and Mesa County, Colorado. The Bureau of Reclamation Economic Assessment Model (BREAM) was used to estimate the increases in employment and increases in personal income in Mesa County that result from the Vicinity Property Program. The effects of program-related changes in income and taxable expenditures on local and state tax revenue are also presented

Comparison of the breeding biology of sympatric red-tailed Hawks, White-tailed Hawks, and Crested Caracaras in south Texas

Science.gov (United States)

Actkinson, M.A.; Kuvlesky, W.P.; Boal, C.W.; Brennan, L.A.; Hernandez, F.

2009-01-01

We compared the breeding biology of sympatric nesting Red-tailed Hawks (Buteo jamaicensis), White-tailed Hawks (Buteo albicaudatus), and Crested Caracaras (Caracara cheriway) in south Texas during 2003 and 2004. We monitored 46 breeding attempts by Red-tailed Hawks, 56 by White-tailed Hawks, and 27 by Crested Caracaras. Observed nesting success was similar for Red-tailed Hawks (62%) and Crested Caracaras (61%), but lower for White-tailed Hawks (51%). Daily survival rates (0.99) were the same for all three species. Red-tailed Hawks and White-tailed Hawks both fledged 1.13 young per nesting pair and Crested Caracaras fledged 1.39 young per nesting pair. All three species nested earlier in 2004 than in 2003; in addition, the overall nesting density of these three species almost doubled from 2003 (1.45 pairs/km2) to 2004 (2.71 pairs/km2). Estimated productivity of all three species was within the ranges reported from other studies. Given extensive and progressive habitat alteration in some areas of south Texas, and the limited distributions of White-tailed Hawks and Crested Caracaras, the presence of large ranches managed for free-range cattle production and hunting leases likely provides important habitat and may be key areas for conservation of these two species. ?? 2009 The Raptor Research Foundation, Inc.

Simulation model of a twin-tail, high performance airplane

Science.gov (United States)

Buttrill, Carey S.; Arbuckle, P. Douglas; Hoffler, Keith D.

1992-01-01

The mathematical model and associated computer program to simulate a twin-tailed high performance fighter airplane (McDonnell Douglas F/A-18) are described. The simulation program is written in the Advanced Continuous Simulation Language. The simulation math model includes the nonlinear six degree-of-freedom rigid-body equations, an engine model, sensors, and first order actuators with rate and position limiting. A simplified form of the F/A-18 digital control laws (version 8.3.3) are implemented. The simulated control law includes only inner loop augmentation in the up and away flight mode. The aerodynamic forces and moments are calculated from a wind-tunnel-derived database using table look-ups with linear interpolation. The aerodynamic database has an angle-of-attack range of -10 to +90 and a sideslip range of -20 to +20 degrees. The effects of elastic deformation are incorporated in a quasi-static-elastic manner. Elastic degrees of freedom are not actively simulated. In the engine model, the throttle-commanded steady-state thrust level and the dynamic response characteristics of the engine are based on airflow rate as determined from a table look-up. Afterburner dynamics are switched in at a threshold based on the engine airflow and commanded thrust.

Flapping foil power generator performance enhanced with a spring-connected tail

Science.gov (United States)

Liu, Zhengliang; Tian, Fang-Bao; Young, John; Lai, Joseph C. S.

2017-12-01

The flexibility effects on the performance of a flapping foil power generator are numerically studied by using the immersed boundary-lattice Boltzmann method at a Reynolds number of 1100. The flapping foil system consists of a rigid NACA0015 foil undergoing harmonic pitch and plunge motions and a passively actuated flat plate pinned to the trailing edge of the rigid foil. The flexibility is modeled by a torsional spring model at the conjuncture of the rigid foil and the tail. Here, a parametric study on mass density and natural frequency is conducted under the optimum kinematic condition of the rigid system identified from the literature and numerical simulations made for reduced frequency f* = 0.04-0.24 and pitch amplitude θ0 = 40°-90°. Four typical cases are discussed in detail by considering time histories of hydrodynamic loads and tail deformations under the optimal and non-optimal kinematic conditions. Results show that under the rigid-system optimal kinematic condition, a tail with appropriate mass density (μ = 0.60) and resonant frequency ( fr*=1.18 ) can improve the maximum efficiency by 7.24% accompanied by an increase of 6.63% in power compared to those of a rigid foil with a rigid tail. This is because the deflection of the tail reduces the low pressure region on the pressure surface (i.e., the lower surface during the upstroke or the upper surface during the downstroke) caused by the leading edge vortex after the stroke reversal, resulting in a higher efficiency. At high flapping frequencies, a spring-connected tail ( fr*=0.13 ) eliminates the large spike in the moment observed in high stiffness cases, reducing the power required for the pitch motion, resulting in 117% improvement in efficiency over that with a rigid tail at a reduced frequency of 0.24.

Crystal Structure of Bacteriophage SPP1 Distal Tail Protein (gp19.1)

Science.gov (United States)

Veesler, David; Robin, Gautier; Lichière, Julie; Auzat, Isabelle; Tavares, Paulo; Bron, Patrick; Campanacci, Valérie; Cambillau, Christian

2010-01-01

Siphophage SPP1 infects the Gram-positive bacterium Bacillus subtilis using its long non-contractile tail and tail-tip. Electron microscopy (EM) previously allowed a low resolution assignment of most orf products belonging to these regions. We report here the structure of the SPP1 distal tail protein (Dit, gp19.1). The combination of x-ray crystallography, EM, and light scattering established that Dit is a back-to-back dimer of hexamers. However, Dit fitting in the virion EM maps was only possible with a hexamer located between the tail-tube and the tail-tip. Structure comparison revealed high similarity between Dit and a central component of lactophage baseplates. Sequence similarity search expanded its relatedness to several phage proteins, suggesting that Dit is a docking platform for the tail adsorption apparatus in Siphoviridae infecting Gram-positive bacteria and that its architecture is a paradigm for these hub proteins. Dit structural similarity extends also to non-contractile and contractile phage tail proteins (gpVN and XkdM) as well as to components of the bacterial type 6 secretion system, supporting an evolutionary connection between all these devices. PMID:20843802

Comparative evaluation of liner materials for inactive uranium-mill-tailings piles

International Nuclear Information System (INIS)

Buelt, J.L.; Barnes, S.M.

1981-01-01

Under the funding of the Department of Energy's Uranium Mill Tailings Remedial Action (UMTRA) Program, Pacific Northwest Laboratory (PNL) has completed the initial accelerated testing phase of eight candidate liner materials. The tests were designed to comparatively evaluate the long term effectiveness of liner materials as a radionuclide and hazardous chemical leachate barrier. The eight materials tested were selected from a technical review of published literature and industrial specialists. Conditions were then identified that would accelerate the aging processes expected in a uranium tailings environment for 1000 years. High calcium leachates were forced through thin layers of clay liners to accelerate the ion exchange rate of sodium and calcium. Asphalt and synthetic materials were accelerated by exposure to elevate temperatures, high concentrations of oxygen, and increased strengths of aqueous oxidizing agents. By comparing the changes of permeability with time of exposure, the most acceptable materials were then identified. These materials are a catalytically airblown asphalt membrane and natural soil amended with sodium bentonite. Both materials showed an increased resistance to leachate penetration throughout the exposure period with final permeabilities less than 10 -7 cm/s. In addition, the asphalt membrane and sodium bentonite are among the least expensive materials to install at a disposal site. Therefore based on their economic and technical merits, these two materials are being evaluated further in field tests at Grand Junction, Colorado

Mineralogy and geochemistry of uranium mill tailings

International Nuclear Information System (INIS)

Pagel, M.; Somot, S.

2002-01-01

We have investigated three main types of uranium mill tailings: (1) acid mill tailings (Mounana, Gabon), (2) neutralized acid mill tailings (Ecarpiere and Jouac, France) and (3) alkaline mill tailings (Lodeve, France). We have focused especially on radium behaviour which is of major environmental concern in these tailings, but other metals were also studied. It is shown that in type 1 , trapping of 226 Ra by anglesite and barite is dominant whereas in types 2 and 3, 226 Ra is mainly or significantly scavenged by Fe- Mn oxyhydroxides. This study points out the importance of keeping conditions in which these oxyhydroxides will be stable for the long-term. Uranium would be also released during acidification of the tailings. This shows the importance to know more about the behavior of Ra during the crystallization of oxyhydroxides and during tailings diagenesis. Therefore, it is very important to study the sorption of Ra by clay minerals or late authigeneous minerals such as barite. (author)

Annual status report on the Uranium Mill Tailings Remedial Action Program

International Nuclear Information System (INIS)

1992-12-01

This fourteenth annual status report for the Uranium Mill Tailings Remedial Action (UMTRA) Project Office summarizes activities of the Uranium Mill Tailings Remedial Action Surface (UMTRA-Surface) and Uranium Mill Tailings Remedial Action Groundwater (UMTRA-Groundwater) Projects undertaken during fiscal year (FY) 1992 by the US Department of Energy (DOE) and other agencies. Project goals for FY 1993 are also presented. An annual report of this type was a statutory requirement through January 1, 1986, pursuant to the Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978, Public Law (PL) 95-604. The DOE will continue to submit annual reports to DOE-Headquarters, the states, tribes, and local representatives through Project completion in order to inform the public of the yearly Project status. The purpose of the remedial action is to stabilize and control the tailings and other residual radioactive material (RRM) located on the inactive uranium processing sites in a safe and environmentally sound manner, and to minimize or eliminate potential health hazards. Commercial and residential properties near designated processing sites that are contaminated with material from the sites, herein referred to as ''vicinity properties (VP),'' are also eligible for remedial action. Included in the UMTRA Project are 24 inactive uranium processing sites and associated VPs located in 10 states, and the VPs associated with the Edgemont, South Dakota, uranium mill currently owned by the Tennessee Valley Authority (TVA) (Figure A.1, Appendix A)

A comparative study of the tail ion distribution with reduced Fokker-Planck models

Science.gov (United States)

McDevitt, C. J.; Tang, Xian-Zhu; Guo, Zehua; Berk, H. L.

2014-03-01

A series of reduced models are used to study the fast ion tail in the vicinity of a transition layer between plasmas at disparate temperatures and densities, which is typical of the gas and pusher interface in inertial confinement fusion targets. Emphasis is placed on utilizing progressively more comprehensive models in order to identify the essential physics for computing the fast ion tail at energies comparable to the Gamow peak. The resulting fast ion tail distribution is subsequently used to compute the fusion reactivity as a function of collisionality and temperature. While a significant reduction of the fusion reactivity in the hot spot compared to the nominal Maxwellian case is present, this reduction is found to be partially recovered by an increase of the fusion reactivity in the neighboring cold region.

A guide to the management of tailings facilities

International Nuclear Information System (INIS)

Bedard, C.; Ferguson, K.; Gladwin, D.; Lang, D.; Maltby, J.; McCann, M.; Poirier, P.; Schwenger, R.; Vezina, S.; West, S.; Duval, J.; Gardiner, E.; Jansons, K.; Lewis, B.; Matthews, J.; Mchaina, D.; Puro, M.; Siwik, R.; Welch, D.

1998-01-01

The 'Guide to the Management of Tailings Facilities' has been developed by the Mining Association of Canada in an effort to provide guidance to its member companies on sound practices for the safe and environmentally responsible management of tailings facilities. The guide is a reference tool to help companies ensure that they are managing their tailings facilities responsibly, integrating environmental and safety considerations in a consistent manner, with continuous improvement in the operation of tailings facilities. The key to managing tailings responsibly is consistent application of engineering capabilities through the full life cycle. The guide provides a basis for the development of customized tailings management systems to address specific needs at individual operations, and deals with environmental impacts, mill tailing characteristics, tailings facility studies and plans, dam and related structure design, and control and monitoring. Aspects relating to tailings facility siting, design, construction, operation, decommissioning and closure are also fully treated. 1 tab., 3 figs

Strong electron bidirectional anisotropies in the distant tail: ISEE 3 observations of polar rain

International Nuclear Information System (INIS)

Baker, D.N.; Bame, S.J.; Feldman, W.C.; Gosling, J.T.; Zwickl, R.D.; Slavin, J.A.; Smith, E.J.

1986-01-01

A detailed observational treatment of bidirectional electrons (--50 to 50 eV)in the distant magnetotail (rapprox. >100 R/sub E/) is presented. It is found that electrons in this energy range commonly exhibit strong, field-aligned anisotropies in the tail lobes. Because of large tail motions, the ISEE 3 data provide extensive sampling of both the north and south lobes in rapid succession. These data demonstrate directly the strong asymmetries that exist between the north and south lobes at any one time. The bidirectional fluxes are found to occur predominantly in the lobe directly connected to the sunward interplanetary magnetic field in the open magnetosphere model (north lobe for away sectors and south lobe for toward sectors). Electron anisotropy and magnetic field data are presented which show the transition from unidirectional (sheath) electron populations to bidirectional (lobe) populations. Thus we demonstrate the open nature of the distant magnetopause and show that the source of the higher-energy, bidirectional lobe electrons is the tailward directed electron heat flux population in the distant magnetosheath. Taken together, the present evidence suggests that the bidirectional electrons that we observe in the distant tail are closely related to the polar rain electrons observed previously at lower altitudes. Furthermore, these data provide strong evidence that the distant tail is composed largely of open magnetic field lines in contradistinction to some recently advanced models

Feasibility Studies on Pipeline Disposal of Concentrated Copper Tailings Slurry for Waste Minimization

Science.gov (United States)

Senapati, Pradipta Kumar; Mishra, Barada Kanta

2017-06-01

The conventional lean phase copper tailings slurry disposal systems create pollution all around the disposal area through seepage and flooding of waste slurry water. In order to reduce water consumption and minimize pollution, the pipeline disposal of these waste slurries at high solids concentrations may be considered as a viable option. The paper presents the rheological and pipeline flow characteristics of copper tailings samples in the solids concentration range of 65-72 % by weight. The tailings slurry indicated non-Newtonian behaviour at these solids concentrations and the rheological data were best fitted by Bingham plastic model. The influence of solids concentration on yield stress and plastic viscosity for the copper tailings samples were discussed. Using a high concentration test loop, pipeline experiments were conducted in a 50 mm nominal bore (NB) pipe by varying the pipe flow velocity from 1.5 to 3.5 m/s. A non-Newtonian Bingham plastic pressure drop model predicted the experimental data reasonably well for the concentrated tailings slurry. The pressure drop model was used for higher size pipes and the operating conditions for pipeline disposal of concentrated copper tailings slurry in a 200 mm NB pipe with respect to specific power consumption were discussed.

Assessing Risks of Mine Tailing Dam Failures

Science.gov (United States)

Concha Larrauri, P.; Lall, U.

2017-12-01

The consequences of tailings dam failures can be catastrophic for communities and ecosystems in the vicinity of the dams. The failure of the Fundão tailings dam at the Samarco mine in 2015 killed 19 people with severe consequences for the environment. The financial and legal consequences of a tailings dam failure can also be significant for the mining companies. For the Fundão tailings dam, the company had to pay 6 billion dollars in fines and twenty-one executives were charged with qualified murder. There are tenths of thousands of active, inactive, and abandoned tailings dams in the world and there is a need to better understand the hazards posed by these structures to downstream populations and ecosystems. A challenge to assess the risks of tailings dams in a large scale is that many of them are not registered in publicly available databases and there is little information about their current physical state. Additionally, hazard classifications of tailings dams - common in many countries- tend to be subjective, include vague parameter definitions, and are not always updated over time. Here we present a simple methodology to assess and rank the exposure to tailings dams using ArcGIS that removes subjective interpretations. The method uses basic information such as current dam height, storage volume, topography, population, land use, and hydrological data. A hazard rating risk was developed to compare the potential extent of the damage across dams. This assessment provides a general overview of what in the vicinity of the tailings dams could be affected in case of a failure and a way to rank tailings dams that is directly linked to the exposure at any given time. One hundred tailings dams in Minas Gerais, Brazil were used for the test case. This ranking approach could inform the risk management strategy of the tailings dams within a company, and when disclosed, it could enable shareholders and the communities to make decisions on the risks they are taking.

Monte Carlo-based tail exponent estimator

Science.gov (United States)

Barunik, Jozef; Vacha, Lukas

2010-11-01

In this paper we propose a new approach to estimation of the tail exponent in financial stock markets. We begin the study with the finite sample behavior of the Hill estimator under α-stable distributions. Using large Monte Carlo simulations, we show that the Hill estimator overestimates the true tail exponent and can hardly be used on samples with small length. Utilizing our results, we introduce a Monte Carlo-based method of estimation for the tail exponent. Our proposed method is not sensitive to the choice of tail size and works well also on small data samples. The new estimator also gives unbiased results with symmetrical confidence intervals. Finally, we demonstrate the power of our estimator on the international world stock market indices. On the two separate periods of 2002-2005 and 2006-2009, we estimate the tail exponent.

Chapter 2. The history of uranium tailings formation in the North of Tajikistan, their current condition. 2.4. Degmai uranium tailings

International Nuclear Information System (INIS)

Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

2012-01-01

Present article is devoted to Degmai uranium tailings. The history of Degmai uranium tailings is presented. The current condition of uranium tailings is described. During the last 6-7 years, together with IAEA experts, monitoring is permanently carried out and the tailings influence on the environment is defined. Radiation and dosimetric investigation results from Degmai tailing' surface (June 2006) are considered.

Three Dimensional Explicit Model for Cometary Tail Ions Interactions with Solar Wind

Science.gov (United States)

Al Bermani, M. J. F.; Alhamed, S. A.; Khalaf, S. Z.; Ali, H. Sh.; Selman, A. A.

2009-06-01

The different interactions between cometary tail and solar wind ions are studied in the present paper based on three-dimensional Lax explicit method. The model used in this research is based on the continuity equations describing the cometary tail-solar wind interactions. Three dimensional system was considered in this paper. Simulation of the physical system was achieved using computer code written using Matlab 7.0. The parameters studied here assumed Halley comet type and include the particle density rho, the particles velocity v, the magnetic field strength B, dynamic pressure p and internal energy E. The results of the present research showed that the interaction near the cometary nucleus is mainly affected by the new ions added to the plasma of the solar wind, which increases the average molecular weight and result in many unique characteristics of the cometary tail. These characteristics were explained in the presence of the IMF.

Risk assessment of tailings facility dam failure

OpenAIRE

Hadzi-Nikolova, Marija; Mirakovski, Dejan; Stefanova, Violeta

2011-01-01

This paper presents the consequences of tailings facility dam failure and therefore the needs for its risk assessment. Tailings are fine-grained wastes of the mining industry, output as slurries, due to mixing with water during mineral processing. Tailings dams vary a lot as it is affected by: tailings characteristics and mill output, site characteristics as: topography, hydrology, geology, groundwater, seismicity and available material and disposal methods. The talings which accumulat...

Baseline risk assessment for groundwater contamination at the uranium mill tailings site near Monument Valley, Arizona. Draft

Energy Technology Data Exchange (ETDEWEB)

1993-09-01

This baseline risk assessment evaluates potential impact to public health or the environment resulting from groundwater contamination at the former uranium mill processing site near Monument Valley, Arizona. The tailings and other contaminated material at this site are being relocated and stabilized in a disposal cell at Mexican Hat, Utah, through the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. The tailings removal is planned for completion by spring 1994. After the tailings are removed, groundwater contamination at the site will continue to be evaluated. This risk assessment is the first document specific to this site for the Groundwater Project. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site.

Placement of radium/barium sludges in tailings areas

International Nuclear Information System (INIS)

Murphy, K.L.; Multamaki, G.E.

1980-01-01

Currently radium is removed from uranium mining and milling effluents by the addition of barium chloride to precipitate the radium as radium/barium sulphate. The precipitate is allowed to settle in sedimentation basins prior to discharge of the effluent. The sedimentation basins are not suitable for final disposal of the sludge, and placement of the sludges in the tailings area has been proposed. The geochemical environment of fresh tailings areas was characterized as an acidic, oxidized surface zone underlain by an alkaline, reduced zone comprising the rest of the tailings. The quantity of sludge produced was estimated to be small relative to the quantity of tailings, and therefor a relatively small amount of radium would be added to the tailings disposal area by the addition of sludge. To confirm whether sludge addition affected radionuclide solubilization, laboratory leaching tests were conducted on slurries of acid leach tailings, and sludge-tailings mixtures. Radium in the (Ra,Ba)SO 4 sludge was at least as stable as radium in the tailings, and the sludge was able to absorb radium released from the tailings. The addition of sludge did not affect uranium and thorium solubilization. From these results it appears that the placement of sludge in tailings areas would not adversely affect the stability of radionuclides in the tailings or sludge. (auth)

Ferric minerals and organic matter change arsenic speciation in copper mine tailings.

Science.gov (United States)

Wang, Peng; Liu, Yunjia; Menzies, Neal W; Wehr, J Bernhard; de Jonge, Martin D; Howard, Daryl L; Kopittke, Peter M; Huang, Longbin

2016-11-01

Arsenic (As) is commonly associated with Cu ore minerals, with the resultant risk that As can be released offsite from mine tailings. We used synchrotron-based fluorescence X-ray absorption near-edge spectroscopy (XANES) imaging to provide in situ, laterally-resolved speciation of As within tailings which differed in magnetite content (5-12%) and organic matter content (0-5%). Although the total As content was lower in tailings with low magnetite (LM), the soluble (pore water) As was actually 7-times higher in LM tailings than in high magnetite (HM) tailings. Additionally, amendment with 5% sugarcane mulch residues (SMR) (for revegetation) further increased soluble As due to the dissolution and oxidation of arsenopyrite or orpiment. Indeed, in HM tailings, arsenopyrite and orpiment initially accounted for 88% of the total As, which decreased to 48% upon the addition of SMR - this being associated with an increase in As V -ferrihydrite from 12% to 52%. In LM tailings, the pattern of As distribution and speciation was similar, with As as As V -ferrihydrite increasing from 57% to 75% upon the addition of SMR. These findings indicate that changes in ore processing technology, such as the recovery of magnetite could have significant environmental consequences regarding the As mobilisation and transformation in mine tailings. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-momentum tail in the Tonks-Girardeau gas under general confining potentials

International Nuclear Information System (INIS)

Moreno, Gustavo A.

2009-01-01

We prove that the ground state momentum distribution of a one-dimensional system of impenetrable bosons exhibits a k -4 tail for any confining potential. We also derive an expression for easily computing the asymptotic occupation numbers and verify our results with an exact numerical approach.

Geomagnetosystem: charged particle trajectories in the geomagnetic tail

International Nuclear Information System (INIS)

Propp, K.E.

1983-01-01

The interaction between the solar wind and the magnetic field of the earth results in the formation of a long tail-like structure extending antisolarward. Of central importance in the explanations of the causes and processes involved in the earth's aurorae is the study of the manner in which the magnetotail is formed and maintained. A realistic model of the steady state magnetic field structure is formulated. The magnetic field model is comprised of the geomagnetic dipole field, the field due to the forward magnetopause currents, and the field due to the magnetotail current system. The values and derivatives of the model magnetic field are made available for any position within the geomagnetosystem as the output from specially designed computer subprograms. By numerically integrating both the exact and the guidingcenter approximation equations of motion the motions of protons with energies from 2 eV to 20 keV were studied. All possible pitch and phase angles were used along with the energies to determine a complete range of starting velocities at the center of the magnetotail 40 earth radii distant from the earth. Considerable pitch angle scattering during traversals of the equatorial plane was observed. Nevertheless, the following results were obtained: 1) the phase averaged exact motion results agree well with the phase independent guidingcenter approximation, 2) the dawn to dusk drift velocity in the equatorial region of the tail is nearly independent of pitch angle, 3) the drift velocity which is due to both field line curvature and field gradient is proportional to the proton energy and is approximately as given adiabatic approximations for energies up to 20 keV

Proceedings of the 15. annual British Columbia MEND ML/ARD workshop : the management of tailings and tailings impoundments

International Nuclear Information System (INIS)

2009-02-01

This Mine Environment Neutral Drainage (MEND) workshop was held to promote the exchange of information and ideas on environmental protection and reclamation associated with mining. The workshop covered a broad spectrum of reclamation issues and the key environmental challenges facing the mining industry, such as acid mine drainage (AMD) control, and metal leaching and acid rock drainage (ML/ARD). The theme for the 2008 workshop was the management of tailings and tailings impoundments. Topics of discussion included hydrogeology and geochemistry; tailings disposal; mitigation; closure plans; and postclosure performance. The emphasis was on full-scale case studies, practical constraints and sustaining successful disposal strategies and remediation. The session on tailings management reviewed overarching policies and practices; methods of subaerial tailings disposal and case studies of tailings management; and detailed investigations of geochemical properties and processes. The conference featured 22 presentations, of which 4 have been catalogued separately for inclusion in this database. refs., tabs., figs

Precision probes of QCD at high energies

Science.gov (United States)

Alioli, Simone; Farina, Marco; Pappadopulo, Duccio; Ruderman, Joshua T.

2017-07-01

New physics, that is too heavy to be produced directly, can leave measurable imprints on the tails of kinematic distributions at the LHC. We use energetic QCD processes to perform novel measurements of the Standard Model (SM) Effective Field Theory. We show that the dijet invariant mass spectrum, and the inclusive jet transverse momentum spectrum, are sensitive to a dimension 6 operator that modifies the gluon propagator at high energies. The dominant effect is constructive or destructive interference with SM jet production. We compare differential next-to-leading order predictions from POWHEG to public 7 TeV jet data, including scale, PDF, and experimental uncertainties and their respective correlations. We constrain a New Physics (NP) scale of 3.5 TeV with current data. We project the reach of future 13 and 100 TeV measurements, which we estimate to be sensitive to NP scales of 8 and 60 TeV, respectively. As an application, we apply our bounds to constrain heavy vector octet colorons that couple to the QCD current. We project that effective operators will surpass bump hunts, in terms of coloron mass reach, even for sequential couplings.

The evolution of tail weaponization in amniotes.

Science.gov (United States)

Arbour, Victoria M; Zanno, Lindsay E

2018-01-31

Weaponry, for the purpose of intraspecific combat or predator defence, is one of the most widespread animal adaptations, yet the selective pressures and constraints governing its phenotypic diversity and skeletal regionalization are not well understood. Here, we investigate the evolution of tail weaponry in amniotes, a rare form of weaponry that nonetheless evolved independently among a broad spectrum of life including mammals, turtles and dinosaurs. Using phylogenetic comparative methods, we test for links between morphology, ecology and behaviour in extant amniotes known to use the tail as a weapon, and in extinct taxa bearing osseous tail armaments. We find robust ecological and morphological correlates of both tail lashing behaviour and bony tail weaponry, including large body size, body armour and herbivory, suggesting these life-history parameters factor into the evolution of antipredator behaviours and tail armaments. We suggest that the evolution of tail weaponry is rare because large, armoured herbivores are uncommon in extant terrestrial faunas, as they have been throughout evolutionary history. © 2018 The Author(s).

Biological effects of long term fine limestone tailings discharge in a fjord ecosystem.

Science.gov (United States)

Brooks, Lucy; Melsom, Fredrik; Glette, Tormod

2015-07-15

Benthic infaunal data collected from 1993 to 2010 were analysed to examine the effect of long term discharge of fine limestone tailings on macrofaunal species assemblages in a fjord. Relative distance from the outfall and proportion of fine tailings in the sediment were correlated with benthic community structure. Diversity decreased with increasing proportion of fine tailings. Biological Traits Analysis (BTA) was used to explore the temporal and spatial effects of the tailings gradient on macrofaunal functional attributes. BTA revealed that all stations along a pressure gradient of fine limestone tailings were dominated by free-living species. As the proportion of fine tailings in the sediment increased, there was an increase in fauna that were smaller, highly mobile, living on or nearer the surface sediment, with shorter lifespans. There was a decrease in permanent tube dwellers, those fauna with low or no mobility, that live deeper in the sediment and have longer lifespans (>5 yrs). Copyright © 2015 Elsevier Ltd. All rights reserved.

Utilization of Foaming Technology in Cemented Paste Backfill of High-Mud Superfine Unclassified Tailings

Directory of Open Access Journals (Sweden)

Jian-wen Zhao

2017-01-01

Full Text Available Due to high-mud content in superfine unclassified tailings (SUT, the viscosity of cemented paste backfill (CPB is high and its pipeline transportation properties are poor. Foaming technology was introduced to prepare a new three-phase flow backfill (TFB using a foaming machine. Then the rheological parameters of TFB with different bubble ratio were measured and their pipeline transportation properties were simulated by Fluent. Besides, the simulation results were further verified by a semi-industrial loop test. The results indicate that the optimum ratio of TFB is a cement-sand ratio of 1 : 8, mass concentration of 70%, and bubble ratio of 20%. Compared with CPB, the decrease of bleeding rate, viscosity, and resistance loss of TFB is 27%, 25%, and 30%, respectively. Therefore, foaming technology is an innovative and feasible solution for high-mud CPB in reducing viscosity, decreasing resistance loss, and improving pipeline transporting efficiency.

Contemporary Pollution Due Old Uranium Tails

International Nuclear Information System (INIS)

Hadjamberdiev, I.

2007-01-01

The areas of our study are uranium mining areas (with tails and dumps) Min-Kush, Kadji-Sai, Mailuu-Suu. These areas situated in different parts of Tien-Shan region. We study the content (and correlations among): level of uranium in environment, immune function and level, level in human teeth. It has been found: content of uranium in river water under tails about 2,0x10-5 gm/litter, and high level in drinking water too 2,0-4,0. Drying grass and flowers uranium content was 0,04-0,51x10-5 gm/gm, most high content were in Tacniatherum crinitum and Atgilops triuncialis. Lams tissues contain 0,005-2,44 mg/g in Min-Kush, 0,03-0,107, in Mailuu-Suu, and 0,001-0,048 mg/g in Kadji-Sai. Human teeth uranium content (Mailuu-Suu): in milk-teeth 0,481x10-6 gm/gm, in former miners 0,7684x10-6 gm/gm. Inhabitants of the area, which not working in uranium industry have 0,6876x10-6 gm/gm. There was low level of immune function (lymphocytes, IgI globulin, etc) in all three regions (in child, in adults, in uranium-mining worked people). There is no doubt of the positive correlations of uranium pollution of water (by underground infiltration from tails) on one hand and, on the other hand - a) grass, b) lambs body, c) human teeth, d) human immune function. Levels of uranium in teeth strictly depend on time of mining contact. (author)

Students' Perceptions of a Highly Controversial yet Keystone Species, the Black-Tailed Prairie Dog: A Case Study

Science.gov (United States)

Fox-Parrish, Lynne; Jurin, Richard R.

2008-01-01

The authors used a case-study methodology to explore the perceptions of 30 9th-grade biology students relative to black-tailed prairie dogs. The case study, which involved classroom- and field-based experiences that focused on black-tailed prairie dogs, revealed 3 major themes: apathy, egocentrism, and naive conceptions. The authors had hoped that…

Rehabilitation of uranium tailings impoundments

International Nuclear Information System (INIS)

Crawley, A.H.

1983-01-01

Under Australian environmental controls relating to the management of uranium tailings, it is no longer acceptable practice to search for a rehabilitation strategy at the end of production when the generation of tailings has ceased. The uranium projects currently in production and those being proposed are tightly regulated by the authorities. The waste management plans must consider site specific factors and must include selection of appropriate disposal sites and design for long term containment. The final encapsulation in engineered facilities must take into account the probable routes to the environment of the tailings. Rehabilitation shoud be undertaken by the mining and milling operators to standards approved by appropriate authorities. Appropriate administrative arrangements are required, by way of technical committees and financial bonds to ensure that agreed standards of rehabilitation may be achieved. Past and present experience with the rehabilitation of uranium tailings impoundments in Australia is discussed

Histone H2A mobility is regulated by its tails and acetylation of core histone tails

International Nuclear Information System (INIS)

Higashi, Tsunehito; Matsunaga, Sachihiro; Isobe, Keisuke; Morimoto, Akihiro; Shimada, Tomoko; Kataoka, Shogo; Watanabe, Wataru; Uchiyama, Susumu; Itoh, Kazuyoshi; Fukui, Kiichi

2007-01-01

Histone tail domains play important roles in cellular processes, such as replication, transcription, and chromosome condensation. Histone H2A has one central and two tail domains, and their functions have mainly been studied from a biochemical perspective. In addition, analyses based on visualization have been employed for functional analysis of some chromatin proteins. In this study, we analyzed histone H2A mobility in vivo by two-photon FRAP, and elucidated that the histone H2A N- and C-terminal tails regulate its mobility. We found that histone H2A mobility was increased following treatment of host cells with a histone deacetylase inhibitor. Our results support a model in which core histone tails directly regulate transcription by interacting with nucleosome DNA via electrostatic interactions

Cylinder Symmetric Measures with the Tail Property

NARCIS (Netherlands)

Balkema, A.A.

2006-01-01

Abstract: A Pareto distribution has the property that any tail of the distribution has the same shape as the original distribution. The exponential distribution and the uniform distribution have the tail property too. The tail property characterizes the univariate generalized Pareto distributions.

SUPER-LUMINOUS TYPE Ic SUPERNOVAE: CATCHING A MAGNETAR BY THE TAIL

International Nuclear Information System (INIS)

Inserra, C.; Smartt, S. J.; Jerkstrand, A.; Fraser, M.; Wright, D.; Smith, K.; Chen, T.-W.; Kotak, R.; Nicholl, M.; Valenti, S.; Pastorello, A.; Benetti, S.; Bresolin, F.; Kudritzki, R. P.; Burgett, W. S.; Chambers, K. C.; Flewelling, H.; Botticella, M. T.; Ergon, M.; Fynbo, J. P. U.

2013-01-01

We report extensive observational data for five of the lowest redshift Super-Luminous Type Ic Supernovae (SL-SNe Ic) discovered to date, namely, PTF10hgi, SN2011ke, PTF11rks, SN2011kf, and SN2012il. Photometric imaging of the transients at +50 to +230 days after peak combined with host galaxy subtraction reveals a luminous tail phase for four of these SL-SNe. A high-resolution, optical, and near-infrared spectrum from xshooter provides detection of a broad He I λ10830 emission line in the spectrum (+50 days) of SN2012il, revealing that at least some SL-SNe Ic are not completely helium-free. At first sight, the tail luminosity decline rates that we measure are consistent with the radioactive decay of 56 Co, and would require 1-4 M ☉ of 56 Ni to produce the luminosity. These 56 Ni masses cannot be made consistent with the short diffusion times at peak, and indeed are insufficient to power the peak luminosity. We instead favor energy deposition by newborn magnetars as the power source for these objects. A semi-analytical diffusion model with energy input from the spin-down of a magnetar reproduces the extensive light curve data well. The model predictions of ejecta velocities and temperatures which are required are in reasonable agreement with those determined from our observations. We derive magnetar energies of 0.4 ∼ 51 erg) ∼ ej (M ☉ ) ∼< 8.6. The sample of five SL-SNe Ic presented here, combined with SN 2010gx—the best sampled SL-SNe Ic so far—points toward an explosion driven by a magnetar as a viable explanation for all SL-SNe Ic.

Radon emanation characteristics of uranium mill tailings

International Nuclear Information System (INIS)

Nielson, K.K.; Freeman, H.D.; Hartley, J.N.; Mauch, M.L.; Rogers, V.C.

1982-01-01

Radon emanation from uranium mill tailings was examined with respect to the mechanisms of emanation and the physical properties of the tailings which affect emanation. Radon emanation coefficients were measured at ambient moisture on 135 samples from the 1981 field test site at the Grand Junction tailings pile. These coefficients showed a similar trend with moisture to those observed previously with uranium ores, and averaged 0.10 + or - 0.02 at dryness and 0.38 + or - 0.04 for all samples having greater than five weight-percent moisture. Small differences were noted between the maximum values of the coefficients for the sand and slime fractions of the tailings. Separate measurements on tailings from the Vitro tailings pile exhibited much lower emanation coefficients for moist samples, and similar coefficients for dry samples. Alternative emanation measurement techniques were examined and procedures are recommended for use in future work

Energy properties of deuterium cluster impacts on TiD targets

International Nuclear Information System (INIS)

Yamamura, Yasunori

1992-01-01

In order to know the energy properties of deuterium atoms in the cluster impact region, the deuterium cluster impact phenomena have been simulated by using the time-evolution Monte Carlo simulation code DYACAT, where the (D) n (n being 100 to 500 ) with energy 500eV/atom are bombarded on TiD targets. For comparison, the energy properties of 500 eV/atom (Al) 500 cluster impacts on amorphous Au targets have also been simulated. In the case of the deuterium cluster impacts on TiD targets, the high energy tail of the energy distribution of deuterium atoms drops so fast. The temperature of the deuterium cluster impact region is less than 100 ev, and it decreases slightly as the cluster size increases due to the enhanced energy removal with reflected deuterium atoms and sputtered deuterium atoms. While in the case of 500 eV/atom (Al) 500 cluster impacts on Au the high-energy tail of the energy distribution of Al atoms due to the big cluster impact can be well described in terms of the Maxwell-Boltzmann function whose temperature is 270 ev. (author)

Assessment of metals content in dandelion (Taraxacum officinale) leaves grown on mine tailings

Science.gov (United States)

Levei, Levente; Andrei, Mariana Lucia; Hoaghia, Maria Alexandra; Ozunu, Alexandru

2017-12-01

Dandelion (Taraxacum officinale) is one of the plant species that has the ability to spontaneously grow on mine tailings, due to its high tolerance for harsh environmental conditions (low nutrients level, high metal contents). The concentrations of Cd, Cu, Pb and Zn were determined in tailings and dandelion leaves grown on nonferrous mine tailings from Romania, while the metal accumulation was assessed by transfer factors (TFs) calculated as the ratio between the metal concentration in plant leaves and in tailings underneath. The results showed that the metal concentrations in tailings ranged between 0.4-8.0 mg/kg Cd, 20-1300 mg/kg Cu, 27-570 mg/kg Pb and 48-800 mg/kg Zn, while the metal concentrations in dandelion ranged between 0.2-4.8 mg/kg Cd, 6.2-17 mg/kg Cu, 0.5-75 mg/kg Pb and 27-260 mg/kg Zn. The TFs were below 0.8 for Cd and Zn and below 0.4 for Cu and Pb and decreased in the following order Cd≥Zn>Cu≥Pb, suggesting the Cd and Zn accumulation capability of dandelion.

Free energy distribution function of a random Ising ferromagnet

International Nuclear Information System (INIS)

Dotsenko, Victor; Klumov, Boris

2012-01-01

We study the free energy distribution function of a weakly disordered Ising ferromagnet in terms of the D-dimensional random temperature Ginzburg–Landau Hamiltonian. It is shown that besides the usual Gaussian 'body' this distribution function exhibits non-Gaussian tails both in the paramagnetic and in the ferromagnetic phases. Explicit asymptotic expressions for these tails are derived. It is demonstrated that the tails are strongly asymmetric: the left tail (for large negative values of the free energy) is much slower than the right one (for large positive values of the free energy). It is argued that at the critical point the free energy of the random Ising ferromagnet in dimensions D < 4 is described by a non-trivial universal distribution function which is non-self-averaging

Heavy mineral concentration from oil sand tailings

Energy Technology Data Exchange (ETDEWEB)

Chachula, F.; Erasmus, N. [Titanium Corp. Inc., Regina, SK (Canada)

2008-07-01

This presentation described a unique technique to recover heavy minerals contained in the froth treatment tailings produced by oil sand mining extraction operations in Fort McMurray, Alberta. In an effort to process waste material into valuable products, Titanium Corporation is developing technology to recover heavy minerals, primarily zircon, and a portion of bitumen contained in the final stage of bitumen processing. The process technology is being developed to apply to all mined oil sands operations in the Fort McMurray region. In 2004, Titanium Corporation commissioned a pilot research facility at the Saskatchewan Research Council to test dry oil sands tailings. In 2005, a bulk sampling pilot plant was connected to the fresh oil sands tailings pipeline on-site in Fort McMurray, where washed sands containing heavy minerals were processed at a pilot facility. The mineral content in both deposited tailings and fresh pipeline tailings was assessed. Analysis of fresh tailings on a daily basis identified a constant proportion of zircon and higher levels of associated bitumen compared with the material in the deposited tailings. The process flow sheet design was then modified to remove bitumen from the heavy minerals and concentrate the minerals. A newly modified flotation process was shown to be a viable processing route to recover the heavy minerals from froth treatment tailings. 8 refs., 9 tabs., 12 figs.

Tail-assisted pitch control in lizards, robots and dinosaurs.

Science.gov (United States)

Libby, Thomas; Moore, Talia Y; Chang-Siu, Evan; Li, Deborah; Cohen, Daniel J; Jusufi, Ardian; Full, Robert J

2012-01-04

In 1969, a palaeontologist proposed that theropod dinosaurs used their tails as dynamic stabilizers during rapid or irregular movements, contributing to their depiction as active and agile predators. Since then the inertia of swinging appendages has been implicated in stabilizing human walking, aiding acrobatic manoeuvres by primates and rodents, and enabling cats to balance on branches. Recent studies on geckos suggest that active tail stabilization occurs during climbing, righting and gliding. By contrast, studies on the effect of lizard tail loss show evidence of a decrease, an increase or no change in performance. Application of a control-theoretic framework could advance our general understanding of inertial appendage use in locomotion. Here we report that lizards control the swing of their tails in a measured manner to redirect angular momentum from their bodies to their tails, stabilizing body attitude in the sagittal plane. We video-recorded Red-Headed Agama lizards (Agama agama) leaping towards a vertical surface by first vaulting onto an obstacle with variable traction to induce a range of perturbations in body angular momentum. To examine a known controlled tail response, we built a lizard-sized robot with an active tail that used sensory feedback to stabilize pitch as it drove off a ramp. Our dynamics model revealed that a body swinging its tail experienced less rotation than a body with a rigid tail, a passively compliant tail or no tail. To compare a range of tails, we calculated tail effectiveness as the amount of tailless body rotation a tail could stabilize. A model Velociraptor mongoliensis supported the initial tail stabilization hypothesis, showing as it did a greater tail effectiveness than the Agama lizards. Leaping lizards show that inertial control of body attitude can advance our understanding of appendage evolution and provide biological inspiration for the next generation of manoeuvrable search-and-rescue robots.

1981 radon barrier field test at Grand Junction uranium mill tailings pile

International Nuclear Information System (INIS)

Hartley, J.N.; Gee, G.W.; Baker, E.G.; Freeman, H.D.

1983-04-01

Technologies to reduce radon released from uranium mill tailings are being investigated by Pacific Northwest Laboratory as part of the Department of Energy's Uranium Mill Tailings Remedial Action Project (UMTRAP) Technology development program. These technologies include: (1) earthen cover systems, (2) multilayer cover systems, and (3) asphalt emulsion radon barrier systems. During the summer of 1981, a field test was initiated at the Grand Junction, Colorado, uranium tailings pile to evaluate and compare the effectiveness of each radon barrier system. Test plots cover about 1.2 ha (3 acres). The field test has demonstrated the effectiveness of all three cover systems in reducing radon release to near background levels ( 2 s - 1 ). In conjunction with the field tests, column tests (1.8 m diameter) were initiated with cover systems similar to those in the larger field test plots. The column tests allow a direct comparison of the two test procedures and also provide detailed information on radon transport

Summary report on reprocessing evaluation of selected inactive uranium mill tailings sites

International Nuclear Information System (INIS)

1983-09-01

Sandia National Laboratories has been assisting the Department of Energy in the Uranium Mill Tailings Remedial Actions Program (UMTRAP) the purpose of which is to implement the provisions of Title I of Public Law 95-604, ''Uranium Mill Tailings Radiation Control Act of 1978.'' As part of this program, there was a need to evaluate the mineral concentration of the residual radioactive materials at some of the designated processing sites to determine whether mineral recovery would be practicable. Accordingly, Sandia contracted Mountain States Research and Development (MSRD), a division of Mountain States Mineral Enterprises, to drill, sample, and test tailings at 12 sites to evaluate the cost of and the revenue that could be derived from mineral recovery. UMTRAP related environmental and engineering sampling and support activities were performed in conjunction with the MSRD operations. This summary report presents a brief description of the various activities in the program and of the data and information obtained and summarizes the results. 8 refs., 9 tabs

Uranium Mill Tailings Remedial Action Project: technical approach document

International Nuclear Information System (INIS)

1986-05-01

The Uranium Mill Tailings Radiation Control Act of 1978, PL95-604, grants the Secretary of Energy authority and responsibility to perform such actions as are necessary to minimize radiation health hazards and other environmental hazards from inactive uranium mill sites. These cleanup actions are to be performed in compliance with the EPA standards (40 CFR Part 192) which became final on March 7, 1983. This document describes the general technical approaches and design criteria that are adopted by the US Department of Energy (DOE) in order to implement Remedial Action Plans (RAPs) and final designs that comply with EPA standards

Characterization and treatment of artisanal gold mine tailings

International Nuclear Information System (INIS)

Andrade Lima, L.R.P. de; Bernardez, L.A.; Barbosa, L.A.D.

2008-01-01

The solid waste generated by artisanal gold mining, with high mercury and gold contents, can be found in several areas in the South America. The present study focused on the tailings of an artisanal gold mine area located in the Brazilian northeastern. Samples of the mine tailings were taken and used to perform a physical and chemical characterization study using X-ray diffraction, scanning electron microscopy, neutron activation, X-ray fluorescence, induced coupled plasma-mass spectrometry, among others analytical methods. The results indicate that the material is composed mainly by quartz and goethite, the characteristic size of the particles (d 50 ) is about 150 μm, and the density is close of that of quartz. The main constituents are silicon, iron, and aluminum. The tailings gold content is of about 1.8 mg/kg and the mercury content is of about 10 mg/kg. A remarkable feature of this solid waste is that the gold and mercury are both concentrated in both the fine and the coarse particles, but not in particles of intermediary size. Leaching studies indicated that the tailings are stable in weak organic acids, but soluble in alkaline and aired cyanide solutions, in which 89% of gold and 100% of mercury are extracted in 24 h. Electroleaching experiments, performed using sodium chloride as electrolyte, indicated that mercury and gold are extracted simultaneously and the recovery of both metals can be as high as 70% in 4 h. In addition, chromium, nickel, and lead are found in relatively large amounts in the solution, which indicate an effectively action of the electroleaching method to clean up solid wastes contaminated with metals

Plant growth-promoting bacteria for phytostabilization of mine tailings.

Science.gov (United States)

Grandlic, Christopher J; Mendez, Monica O; Chorover, Jon; Machado, Blenda; Maier, Raina M

2008-03-15

Eolian dispersion of mine tailings in arid and semiarid environments is an emerging global issue for which economical remediation alternatives are needed. Phytostabilization, the revegetation of these sites with native plants, is one such alternative. Revegetation often requires the addition of bulky amendments such as compost which greatly increases cost. We report the use of plant growth-promoting bacteria (PGPB) to enhance the revegetation of mine tailings and minimize the need for compost amendment. Twenty promising PGPB isolates were used as seed inoculants in a series of greenhouse studies to examine revegetation of an extremely acidic, high metal contenttailings sample previously shown to require 15% compost amendment for normal plant growth. Several isolates significantly enhanced growth of two native species, quailbush and buffalo grass, in tailings. In this study, PGPB/compost outcomes were plant specific; for quailbush, PGPB were most effective in combination with 10% compost addition while for buffalo grass, PGPB enhanced growth in the complete absence of compost. Results indicate that selected PGPB can improve plant establishment and reduce the need for compost amendment. Further, PGPB activities necessary for aiding plant growth in mine tailings likely include tolerance to acidic pH and metals.

On the average configuration of the geomagnetic tail

International Nuclear Information System (INIS)

Fairfield, D.H.

1978-03-01

Over 3000 hours of IMP-6 magnetic field data obtained between 20 and 33 R sub E in the geomagnetic tail have been used in a statistical study of the tail configuration. A distribution of 2.5 minute averages of B sub Z as a function of position across the tail reveals that more flux crosses the equatorial plane near the dawn and dusk flanks than near midnight. The tail field projected in the solar magnetospheric equatorial plane deviates from the X axis due to flaring and solar wind aberration by an angle alpha = -0.9 y sub SM - 1.7, where y/sub SM/ is in earth radii and alpha is in degrees. After removing these effects the Y component of the tail field is found to depend on interplanetary sector structure. During an away sector the B/sub Y/ component of the tail field is on average 0.5 gamma greater than that during a toward sector, a result that is true in both tail lobes and is independent of location across the tail

Understanding AL-PAM assisted oil sands tailings treatment

Energy Technology Data Exchange (ETDEWEB)

Guo, L.; Maham, Y.; Masliyah, J.; Xu, Z. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

2010-07-01

Technologies currently used to treat oil sands tailings include the composite tailings (CT) process and the thickened tailings (TT) or paste technology process. This PowerPoint presentation discussed a flocculation and filtration method used to produce stackable tailings deposits. Magnafloc 1011 and AL-PAM additions were used as part of the filtration technique to produce very dry filter cakes. The effect of AL-PAM molecular weight and aluminum content on tailings treatments was investigated as well as the effect of tailings characteristics on the performance of flocculant-assisted tailings filtration processes. The AL-PAM molecular structure was studied. An experimental study was conducted to determine the effect of various polymer additions on fresh tailings from an oil sands plant. The study showed that the optimum dosage for settling and filtration was lower for higher molecular weight AL-PAM. A higher aluminum content was beneficial for settling. Increases in the aluminum content did not improve filtration rates, but reduced optimal dosages. Step-by-step details of the supernatant filtration process were provided, as well as photographs of the laboratory study. tabs., figs.

Adaptation and detoxification mechanisms of Vetiver grass (Chrysopogon zizanioides) growing on gold mine tailings.

Science.gov (United States)

Melato, F A; Mokgalaka, N S; McCrindle, R I

2016-01-01

Vetiver grass (Chrysopogon zizanioides) was investigated for its potential use in the rehabilitation of gold mine tailings, its ability to extract and accumulate toxic metals from the tailings and its metal tolerant strategies. Vetiver grass was grown on gold mine tailings soil, in a hothouse, and monitored for sixteen weeks. The mine tailings were highly acidic and had high electrical conductivity. Vetiver grass was able to grow and adapt well on gold mine tailings. The results showed that Vetiver grass accumulated large amounts of metals in the roots and restricted their translocation to the shoots. This was confirmed by the bioconcentration factor of Zn, Cu, and Ni of >1 and the translocation factor of <1 for all the metals. This study revealed the defense mechanisms employed by Vetiver grass against metal stress that include: chelation of toxic metals by phenolics, glutathione S-tranferase, and low molecular weight thiols; sequestration and accumulation of metals within the cell wall that was revealed by the scanning electron microscopy that showed closure of stomata and thickened cell wall and was confirmed by high content of cell wall bound phenolics. Metal induced reactive oxygen species are reduced or eliminated by catalase, superoxide dismutase and peroxidase dismutase.

Numerical study on the power extraction performance of a flapping foil with a flexible tail

Science.gov (United States)

Wu, J.; Shu, C.; Zhao, N.; Tian, F.-B.

2015-01-01

The numerical study on the power extraction performance of a flapping foil with a flexible tail is performed in this work. A NACA0015 airfoil is arranged in a two-dimensional laminar flow and imposed with a synchronous harmonic plunge and pitch rotary motion. A flat plate that is attached to the trailing edge of the foil is utilized to model a tail, and so they are viewed as a whole for the purpose of power extraction. In addition, the tail either is rigid or can deform due to the exerted hydrodynamic forces. To implement numerical simulations, an immersed boundary-lattice Boltzmann method is employed. At a Reynolds number of 1100 and the position of the pitching axis at third chord, the influences of the mass and flexibility of the tail as well as the frequency of motion on the power extraction are systematically examined. It is found that compared to the foil with a rigid tail, the efficiency of power extraction for the foil with a deformable tail can be improved. Based on the numerical analysis, it is indicated that the enhanced plunging component of the power extraction, which is caused by the increased lift force, directly contributes to the efficiency improvement. Since a flexible tail with medium and high masses is not beneficial to the efficiency improvement, a flexible tail with low mass together with high flexibility is recommended in the flapping foil based power extraction system.

Proceedings of the 2. international oil sands tailings conference

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-01

The tailings produced by oil sands extraction processes pose significant threats to the surrounding environment in addition to releasing greenhouse gases (GHGs) into the atmosphere. Recent directives have been established to reduce the amount of tailings produced at oil sands operations, and to ensure that tailings ponds are reclaimed in the most effective manner. This conference provided a forum for researchers and industry experts to discuss issues related to the management and reclamation of oil sands tailings. New technologies for dewatering tailings ponds were presented, and methods of analyzing the chemical properties of tailings were reviewed. The conference was divided into the following 7 sessions: (1) tailings properties, (2) tailings dewatering, (3) new concepts, (4) water and chemistry, (5) soft tailings stabilization and reclamation, (6) water treatment, and (7) new concepts 2. The conference featured 44 presentations, all of which have been catalogued separately for inclusion in this database. tabs., figs.

Revegetation and rock cover for stabilization of inactive uranium mill tailings disposal sites. Final report

Energy Technology Data Exchange (ETDEWEB)

Beedlow, P.A.

1984-05-01

Guidelines for using vegetation and rock to protect inactive uranium mill tailings from erosion were developed by Pacific Northwest Laboratory as part of the Department of Energy's Uranium Mill Tailings Remedial Action Project (UMTRAP) Technology Development program. Information on soils, climate, and vegetation were collected for 20 inactive tailings sites in the western United States. Sites were grouped according to similarities in climate and vegetation. Soil loss for those sites was characterized using the Universal Soil Loss Equation. Test plots were used to evaluate (1) the interaction between vegetation and sealant barrier systems and (2) the effects of surface rock on soil water and vegetation. Lysimeter and simulation studies were used to direct and support field experiments. 49 references, 17 figures, 16 tables.

Revegetation and rock cover for stabilization of inactive uranium mill tailings disposal sites. Final report

International Nuclear Information System (INIS)

Beedlow, P.A.

1984-05-01

Guidelines for using vegetation and rock to protect inactive uranium mill tailings from erosion were developed by Pacific Northwest Laboratory as part of the Department of Energy's Uranium Mill Tailings Remedial Action Project (UMTRAP) Technology Development program. Information on soils, climate, and vegetation were collected for 20 inactive tailings sites in the western United States. Sites were grouped according to similarities in climate and vegetation. Soil loss for those sites was characterized using the Universal Soil Loss Equation. Test plots were used to evaluate (1) the interaction between vegetation and sealant barrier systems and (2) the effects of surface rock on soil water and vegetation. Lysimeter and simulation studies were used to direct and support field experiments. 49 references, 17 figures, 16 tables

Studies on Arsenic Release and its Mitigation from Tailings Dam ...

African Journals Online (AJOL)

user

R is the Ideal gas constant (8.314 J/K mol). T is the temperature in K. A negative Gibbs free energy value (-12.1026 kJ/ mol) was obtained. This indicates that the adsorption of As from the mine tailings leachate onto the nanomagnetite (20 nm Fe3O4) material is spontane- ous and that the reaction is thermodynamically feasi-.

Unique structural features facilitate lizard tail autotomy

DEFF Research Database (Denmark)

Sanggaard, Kristian W; Danielsen, Carl Chr; Wogensen, Lise

2012-01-01

Autotomy refers to the voluntary shedding of a body part; a renowned example is tail loss among lizards as a response to attempted predation. Although many aspects of lizard tail autotomy have been studied, the detailed morphology and mechanism remains unclear. In the present study, we showed...... that tail shedding by the Tokay gecko (Gekko gecko) and the associated extracellular matrix (ECM) rupture were independent of proteolysis. Instead, lizard caudal autotomy relied on biological adhesion facilitated by surface microstructures. Results based on bio-imaging techniques demonstrated that the tail...

A study of bauxite tailing quality improvement by reverse flotation

Science.gov (United States)

Wulandari, W.; Purwasasmita, M.; Sanwani, E.; Malatsih, W.; Fadilla, F.

2018-01-01

The pre-treatment of bauxite ore from Tayan, West Kalimantan includes washing and screening fine bauxite particles (-2mm) prior as the feed to the Bayer process for producing alumina. These fine particles are believed to have high content of silica which is detrimental to the process. This washed bauxite tailing still has a significant amount of alumina content. Previous research has indicated that bauxite ore can be upgraded by applying reverse flotation method to reduce its silica content in the ore. Therefore, this study is aimed to utilize reverse flotation method to recover alumina content from washed bauxite tailing. The reverse flotation experiments were carried out at pH of 6 and 8; while the particle sizes were varied at - 140+270 mesh and -270 mesh, using a batch and circuit configuration. The result of this study shows that the batch reverse flotation can recover alumina in the tailing up to 81.4%, however the silica content is still significant. The complexity of silica-alumina minerals in the tailing prevents a complete separation of the ores by only using reverse flotation.

MESSENGER Observations of Extreme Magnetic Tail Loading and Unloading During its Third Flyby of Mercury: Substorms?

Science.gov (United States)

Slavin, James A.; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Gloeckler, George; Krimigis, Stamatios M.; McNutt, Ralph L., Jr.; Schriver, David; Solomon, Sean C.; Zurbuchen, Thomas H.

2010-01-01

During MESSENGER's third flyby of Mercury on September 29, 2009, a variable interplanetary magnetic field produced a series of several minute enhancements of the tail magnetic field hy factors of approx. 2 to 3.5. The magnetic field flaring during these intervals indicates that they result from loading of the tail with magnetic flux transferred from the dayside magnetosphere. The unloading intervals were associated with plasmoids and traveling compression regions, signatures of tail reconnection. The peak tail magnetic flux during the smallest loading events equaled 30% of the magnetic flux emanating from Mercury, and may have reached 100% for the largest event. In this case the dayside magnetic shielding is reduced and solar wind flux impacting the surface may be greatly enhanced. Despite the intensity of these events and their similarity to terrestrial substorm magnetic flux dynamics, no energetic charged particles with energies greater than 36 keV were observed.

Chlorophyll a with a farnesyl tail in thermophilic cyanobacteria.

Science.gov (United States)

Wiwczar, Jessica M; LaFountain, Amy M; Wang, Jimin; Frank, Harry A; Brudvig, Gary W

2017-11-01

Photosystem II (PSII) of oxygenic photosynthetic organisms normally contains exclusively chlorophyll a (Chl a) as its major light-harvesting pigment. Chl a canonically consists of the chlorin headgroup with a 20-carbon, 4-isoprene unit, phytyl tail. We have examined the 1.9 Å crystal structure of PSII from thermophilic cyanobacteria reported by Shen and coworkers in 2012 (PDB accession of 3ARC/3WU2). A newly refined electron density map from this structure, presented here, reveals that some assignments of the cofactors may be different from those modeled in the 3ARC/3WU2 structure, including a specific Chl a that appears to have a truncated tail by one isoprene unit. We provide experimental evidence using high-performance liquid chromatography and mass spectrometry for a small population of Chl a esterified to a 15-carbon farnesyl tail in PSII of thermophilic cyanobacteria.

Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Site near Riverton, Wyoming

Energy Technology Data Exchange (ETDEWEB)

1994-09-01

This Risk Assessment evaluated potential impacts to public health or the environment caused by ground water contamination at the former uranium mill processing site. In the first phase of the U.S. Department of Energy`s Uranium Mill Tailings Remedial Action (UMTRA) Project, the tailing and other contaminated material at this site were placed in a disposal cell near the Gas Hills Plant in 1990. The second phase of the UMTRA Project is to evaluate ground water contamination. This risk assessment is the first site-specific document to evaluate potential health and environmental risks for the Riverton site under the Ground Water Project; it will help determine whether remedial actions are needed for contaminated ground water at the site.

Health risks from uranium mill tailings

International Nuclear Information System (INIS)

Russell, J.L.

1992-01-01

This paper reviews the risk to public health and the environment from uranium mill tailings. The steps taken by the Environmental Protection Agency (EPA) to reduce this risk from tailing are summarized

Description of an α-cluster tail in 8Be and 20Ne: Delocalization of the α cluster by quantum penetration

Science.gov (United States)

Kanada-En'yo, Yoshiko

2014-10-01

We analyze the α-cluster wave functions in cluster states of ^8Be and ^{20}Ne by comparing the exact relative wave function obtained by the generator coordinate method (GCM) with various types of trial functions. For the trial functions, we adopt the fixed range shifted Gaussian of the Brink-Bloch (BB) wave function, the spherical Gaussian with the adjustable range parameter of the spherical Tohsaki-Horiuchi-Schuck-Röpke (sTHSR), the deformed Gaussian of the deformed THSR (dTHSR), and a function with the Yukawa tail (YT). The quality of the description of the exact wave function with a trial function is judged by the squared overlap between the trial function and the GCM wave function. A better result is obtained with the sTHSR wave function than the BB wave function, and further improvement can be made with the dTHSR wave function because these wave functions can describe the outer tail better. The YT wave function gives almost an equal quality to or even better quality than the dTHSR wave function, indicating that the outer tail of α-cluster states is characterized by the Yukawa-like tail rather than the Gaussian tail. In weakly bound α-cluster states with small α separation energy and the low centrifugal and Coulomb barriers, the outer tail part is the slowly damping function described well by the quantum penetration through the effective barrier. This outer tail characterizes the almost zero-energy free α gas behavior, i.e., the delocalization of the cluster.

Bidirectional electron anisotropies in the distant tail: ISEE-3 observations of polar rain

International Nuclear Information System (INIS)

Baker, D.N.; Bame, S.J.; Feldman, W.C.; Gosling, J.T.; Zwickl, R.D.; Slavin, J.A.; Smith, E.J.

1985-01-01

A detailed observational treatment of bidirectional electrons (50 approx.500 eV) in the distant magnetotail (r greater than or equal to 100 R/sub E/) is presented. It is found that electrons in this energy range commonly exhibit strong, field-aligned anisotropies in the tail lobes. Because of large tail motions, the ISEE-3 data provide extensive sampling of both the north and south lobes in rapid succession, demonstrating directly the strong asymmetries that exist between the north and south lobes at any one time. The bidirectional fluxes are found to occur predominantly in the lobe directly connected to the sunward IMF in the open magnetosphere model (north lobe for away sectors and south lobe for toward sectors). Electron anisotropy and magnetic field data are presented which show the transition from unidirectional (sheath) electron populations to bidirectional (lobe) populations. Taken together, the present evidence suggests that the bidirectional electrons that we observe in the distant tail are closely related to the polar rain electrons observed previously at lower altitudes. Furthermore, these data provide strong evidence that the distant tail is comprised largely of open magnetic field lines in contradistinction to some recently advanced models

Big picture thinking in oil sands tailings disposal

Energy Technology Data Exchange (ETDEWEB)

Boswell, J. [Thurber Engineering Ltd., Calgary, AB (Canada)

2010-07-01

This PowerPoint presentation discussed methods of disposing oil sands tailings. Oil sands operators are currently challenged by a variety of legislative and environmental factors concerning the creation and disposal of oil sands tailings. The media has focused on the negative ecological impact of oil sands production, and technical issues are reducing the effect of some mitigation processes. Operators must learn to manage the interface between tailings production and removal, the environment, and public opinion. The successful management of oil sand tailings will include procedures designed to improve reclamation processes, understand environmental laws and regulations, and ensure that the cumulative impacts of tailings are mitigated. Geotechnical investigations, engineering designs and various auditing procedures can be used to develop tailings management plans. Environmental screening and impact assessments can be used to develop sustainable solutions. Public participation and environmental mediation is needed to integrate the public, environmental and technical tailings management strategies. Operators must ensure public accountability for all stakeholders. tabs., figs.

Research on uranium tailings disposal technology at CANMET, Ottawa

International Nuclear Information System (INIS)

Skeaff, J.M.; Ritcey, G.M.; Jongejan, A.; Silver, M.

1982-01-01

In this paper, results from three continuing investigations at CANMET on uranium tailings management are presented. These investigations are: cleaning of tailings by flotation, conversion of municipal wastes into compost for use as topsoil on uranium tailings, methods for the chemical fixation of uranium tailings and a laboratory determination of the rate of release of environmental contaminants from uranium tailings

Effect of high-pressure homogenization preparation on mean globule size and large-diameter tail of oil-in-water injectable emulsions.

Science.gov (United States)

Peng, Jie; Dong, Wu-Jun; Li, Ling; Xu, Jia-Ming; Jin, Du-Jia; Xia, Xue-Jun; Liu, Yu-Ling

2015-12-01

The effect of different high pressure homogenization energy input parameters on mean diameter droplet size (MDS) and droplets with > 5 μm of lipid injectable emulsions were evaluated. All emulsions were prepared at different water bath temperatures or at different rotation speeds and rotor-stator system times, and using different homogenization pressures and numbers of high-pressure system recirculations. The MDS and polydispersity index (PI) value of the emulsions were determined using the dynamic light scattering (DLS) method, and large-diameter tail assessments were performed using the light-obscuration/single particle optical sensing (LO/SPOS) method. Using 1000 bar homogenization pressure and seven recirculations, the energy input parameters related to the rotor-stator system will not have an effect on the final particle size results. When rotor-stator system energy input parameters are fixed, homogenization pressure and recirculation will affect mean particle size and large diameter droplet. Particle size will decrease with increasing homogenization pressure from 400 bar to 1300 bar when homogenization recirculation is fixed; when the homogenization pressure is fixed at 1000 bar, the particle size of both MDS and percent of fat droplets exceeding 5 μm (PFAT 5 ) will decrease with increasing homogenization recirculations, MDS dropped to 173 nm after five cycles and maintained this level, volume-weighted PFAT 5 will drop to 0.038% after three cycles, so the "plateau" of MDS will come up later than that of PFAT 5 , and the optimal particle size is produced when both of them remained at plateau. Excess homogenization recirculation such as nine times under the 1000 bar may lead to PFAT 5 increase to 0.060% rather than a decrease; therefore, the high-pressure homogenization procedure is the key factor affecting the particle size distribution of emulsions. Varying storage conditions (4-25°C) also influenced particle size, especially the PFAT 5 . Copyright

Experimental investigation of ice and snow melting process on pavement utilizing geothermal tail water

International Nuclear Information System (INIS)

Wang Huajun; Zhao Jun; Chen Zhihao

2008-01-01

Road ice and snow melting based on low temperature geothermal tail water is of significance to realize energy cascading utilization. A small scale ice and snow melting system is built in this work. Experiments of dynamic melting processes of crushed ice, solid ice, artificial snow and natural snow are conducted on concrete pavement. The results show that the melting process of ice and snow includes three phases: a starting period, a linear period and an accelerated period. The critical value of the snow free area ratio between the linear period and the accelerated period is about 0.6. The physical properties of ice and snow, linked with ambient conditions, have an obvious effect on the melting process. The difference of melting velocity and melting time between ice and snow is compared. To reduce energy consumption, the formation of ice on roads should be avoided if possible. The idling process is an effective pathway to improve the performance of melting systems. It is feasible to utilize geothermal tail water of about 40 deg. C for melting ice and snow on winter roads, and it is unnecessary to keep too high fluid temperatures during the practical design and applications. Besides, with the exception of solid ice, the density and porosity of snow and ice tend to be decreasing and increasing, respectively, as the ambient temperature decreases

Environmental assessment of remedial action at the Gunnison Uranium Mill Tailings Site, Gunnison, Colorado

International Nuclear Information System (INIS)

Bachrach, A.; Hoopes, J.; Morycz, D.; Bone, M.; Cox, S.; Jones, D.; Lechel, D.; Meyer, C.; Nelson, M.; Peel, R.; Portillo, R.; Rogers, L.; Taber, B.; Zelle, P.; Rice, G.

1984-12-01

This document assesses and compares the environmental impacts of various alternatives for remedial action at the Gunnison uranium of mill tailings site located 0.5 miles south of Gunnison, Colorado. The site covers 56 acres and contains 35 acres of tailings, 2 of the original mill buildings and a water tower. The Uranium Mill Tailings Radiation Control of Act of 1978 (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated [vicinity] properties off the site. The US Environmental Protection Agency promulgated standards for the remedial actions (40 CFR 192). Remedial actions must be performed in accordance with these standards and with the occurrence of the Nuclear Regulatory Commission. Four alternatives have been addressed in this document. The first alternative is to consolidate the tailings and associated contaminated soils into a recontoured pile on the southern portion of the existing site. A radon barrier of silty clay would be constructed over the pile and various erosion control measures would be taken to assure the long-term integrity of the pile. Two other alternatives which involve moving the tailings to new locations are assessed in this document. These alternatives generally involve greater short-term impacts and are more costly but would result in the tailings being stabilized in a location farther from the city of Gunnison. The no action alternative is also assessed

Tail function during arboreal quadrupedalism in squirrel monkeys (Saimiri boliviensis) and tamarins (Saguinus oedipus).

Science.gov (United States)

Young, Jesse W; Russo, Gabrielle A; Fellmann, Connie D; Thatikunta, Meena A; Chadwell, Brad A

2015-10-01

The need to maintain stability on narrow branches is often presented as a major selective force shaping primate morphology, with adaptations to facilitate grasping receiving particular attention. The functional importance of a long and mobile tail for maintaining arboreal stability has been comparatively understudied. Tails can facilitate arboreal balance by acting as either static counterbalances or dynamic inertial appendages able to modulate whole-body angular momentum. We investigate associations between tail use and inferred grasping ability in two closely related cebid platyrrhines-cotton-top tamarins (Saguinus oedipus) and black-capped squirrel monkeys (Saimiri boliviensis). Using high-speed videography of captive monkeys moving on 3.2 cm diameter poles, we specifically test the hypothesis that squirrel monkeys (characterized by grasping extremities with long digits) will be less dependent on the tail for balance than tamarins (characterized by claw-like nails, short digits, and a reduced hallux). Tamarins have relatively longer tails than squirrel monkeys, move their tails through greater angular amplitudes, at higher angular velocities, and with greater angular accelerations, suggesting dynamic use of tail to regulate whole-body angular momentum. By contrast, squirrel monkeys generally hold their tails in a comparatively stationary posture and at more depressed angles, suggesting a static counterbalancing mechanism. This study, the first empirical test of functional tradeoffs between grasping ability and tail use in arboreal primates, suggests a critical role for the tail in maintaining stability during arboreal quadrupedalism. Our findings have the potential to inform our functional understanding of tail loss during primate evolution. © 2015 Wiley Periodicals, Inc.

Engineering assessment of inactive uranium mill tailings

Energy Technology Data Exchange (ETDEWEB)

1981-07-01

The Grand Junction site has been reevaluated in order to revise the October 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Grand Junction, Colorado. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.9 million tons of tailings at the Grand Junction site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The eight alternative actions presented herein range from millsite and off-site decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings to remote disposal sites and decontamination of the tailings site (Options II through VIII). Cost estimates for the eight options range from about $10,200,000 for stabilization in-place to about $39,500,000 for disposal in the DeBeque area, at a distance of about 35 mi, using transportation by rail. If transportation to DeBeque were by truck, the cost estimated to be about $41,900,000. Three principal alternatives for the reprocessing of the Grand Junction tailings were examined: (a) heap leaching; (b) treatment at an existing mill; and (c) reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be about $200/lb by heap leach and $150/lb by conventional plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery appears not to be economically attractive.

Engineering assessment of inactive uranium mill tailings

International Nuclear Information System (INIS)

1981-07-01

The Grand Junction site has been reevaluated in order to revise the October 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Grand Junction, Colorado. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.9 million tons of tailings at the Grand Junction site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The eight alternative actions presented herein range from millsite and off-site decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings to remote disposal sites and decontamination of the tailings site (Options II through VIII). Cost estimates for the eight options range from about $10,200,000 for stabilization in-place to about $39,500,000 for disposal in the DeBeque area, at a distance of about 35 mi, using transportation by rail. If transportation to DeBeque were by truck, the cost estimated to be about $41,900,000. Three principal alternatives for the reprocessing of the Grand Junction tailings were examined: (a) heap leaching; (b) treatment at an existing mill; and (c) reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be about $200/lb by heap leach and $150/lb by conventional plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery appears not to be economically attractive

Four tails problems for dynamical collapse theories

Science.gov (United States)

McQueen, Kelvin J.

2015-02-01

The primary quantum mechanical equation of motion entails that measurements typically do not have determinate outcomes, but result in superpositions of all possible outcomes. Dynamical collapse theories (e.g. GRW) supplement this equation with a stochastic Gaussian collapse function, intended to collapse the superposition of outcomes into one outcome. But the Gaussian collapses are imperfect in a way that leaves the superpositions intact. This is the tails problem. There are several ways of making this problem more precise. But many authors dismiss the problem without considering the more severe formulations. Here I distinguish four distinct tails problems. The first (bare tails problem) and second (structured tails problem) exist in the literature. I argue that while the first is a pseudo-problem, the second has not been adequately addressed. The third (multiverse tails problem) reformulates the second to account for recently discovered dynamical consequences of collapse. Finally the fourth (tails problem dilemma) shows that solving the third by replacing the Gaussian with a non-Gaussian collapse function introduces new conflict with relativity theory.

A Note on Upper Tail Behavior of Liouville Copulas

Directory of Open Access Journals (Sweden)

Lei Hua

2016-11-01

Full Text Available The family of Liouville copulas is defined as the survival copulas of multivariate Liouville distributions, and it covers the Archimedean copulas constructed by Williamson’s d-transform. Liouville copulas provide a very wide range of dependence ranging from positive to negative dependence in the upper tails, and they can be useful in modeling tail risks. In this article, we study the upper tail behavior of Liouville copulas through their upper tail orders. Tail orders of a more general scale mixture model that covers Liouville distributions is first derived, and then tail order functions and tail order density functions of Liouville copulas are derived. Concrete examples are given after the main results.

Why high energy physics

International Nuclear Information System (INIS)

Diddens, A.N.; Van de Walle, R.T.

1981-01-01

An argument is presented for high energy physics from the point of view of the practitioners. Three different angles are presented: The cultural consequence and scientific significance of practising high energy physics, the potential application of the results and the discovery of high energy physics, and the technical spin-offs from the techniques and methods used in high energy physics. (C.F.)

Radioactivity in tomatoes grown on mine tailings from Oka, a niobium mining region

International Nuclear Information System (INIS)

Boulet, M.; Boudreau, A.; Roy, J.C.

1983-01-01

The radioactivity contained in the tailings of a niobium mine in the Oka region, Quebec, was the object of concern for the population of the area in 1979. To find the impact of these tailings on fruit and vegetables grown in this environment, an investigation of the radioactivity found on tomatoes grown in green houses in niobium tailings and in vermiculites was undertaken. The tailings contained a high level of natural radioactivity and a small amount of 137 Cs while the vermiculites had a very low level of natural radioactivity and an appreciable amount of 137 Cs. Cesium-137 was the only nuclide detected in tomato ashes in measurable quantity. Absence of natural radioactivity is explained by its presence as insoluble minerals

Solar wind interaction with type-1 comet tails

International Nuclear Information System (INIS)

Ershkovich, A.I.

1977-01-01

A comet tail is considered as a plasma cylinder separated by a tangential discontinuity surface from the solar wind. Under typical conditions a comet tail boundary is shown to undergo the Kelvin-Helmholtz instability. With infinite amplitude the stabilizing effect of the magnetic field increases, and waves become stable. The proposed model supplies the detailed quantitative description of helical waves observed in type-1 comet tails. This theory enables the evaluation of the comet tail magnetic field by means of the observations of helical waves. The magnetic field in the comet tail turns out to be of the order of the interplanetary field. This conclusion seems to be in accordance with Alfven's idea that the magnetic field in type-1 comet tails is a captured interplanetary field. (Auth.)

Summary of the engineering assessment of inactive uranium-mill tailings: Canonsburg Site, Canonsburg, Pennsylvania

International Nuclear Information System (INIS)

1982-04-01

Ford, Bacon and Davis Utah Inc. has evaluated the Canonsburg site in order to assess the problems resulting from the existence of radioactive residues at Canonsburg, Pennsylvania. This engineering assessment has included the preparation of topographic maps, radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative remedial actions. Radon gas released from the approximately 300,000 tons of tailings and contaminated soil at the Canonsburg site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The four alternative actions presented in this engineering assessment range from millsite and off-site decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings and contaminated materials to a remote disposal site and decontamination of the Canonsburg site (Options II through IV). Cost estimates for the four options range from $23,244,000 for stabilization in-place, to $27,052,000 for disposal at a distance of about 17 mi. Three principal alternatives for the reprocessing of the Canonsburg tailings were examined: heap leaching; treatment at an existing mill; and reprocessing at a new conventional mill constructed for tailings reprocessing. As required by Public Law 95-604, under whose auspices this project is conducted, the US Department of Energy has solicited expressions of interest in reprocessing the tailings and residues at the Canonsburg site for uranium recovery. Since no such interest was demonstrated, no effort has been made to estimate the value of the residual uranium resource at the Canonsburg site

Mineralogical characterization of arsenic, iron, and nickel in uranium mine tailings using XAS and EMPA

International Nuclear Information System (INIS)

Essilfie-Dughan, J.; Hendry, M.J.; Warner, J.; Kotzer, T.

2010-01-01

In northern Saskatchewan, Canada, high-grade uranium ores and the resulting tailings can contain high levels of arsenic (As), iron (Fe), and nickel (Ni). An environmental concern in the uranium mining industry is the long-term stabilization of these elements of concern (EOCs) within tailings management facilities thereby mitigating their transfer to the surrounding groundwater. Characterization of these As-, Fe- and Ni-bearing minerals and complexes must be carried out to evaluate their solubility and long-term stability within the tailings mass. Synchrotron-based bulk x-ray absorption spectroscopy (XAS) has been used to study the speciation of these EOCs in mine tailing samples obtained from the Deilmann Tailings Management Facility (DTMF) at Key Lake, Saskatchewan. Electron microprobe analysis (EMPA) and synchrotron-based micro-focussing x-ray fluorescence mapping and absorption spectroscopy (μXRF; μXAS ) have also been employed to study spatial distribution and speciation at the micron scale. Comparisons of K-edge absorption spectra of tailings samples and reference compounds indicate the dominant oxidation states of As, Fe, and Ni in the mine tailings samples are +5, +3, and +2, respectively, largely reflecting their deposition in an oxidized environment and complexation within stable oxic phases. Backscattered electron (BSE) images of the tailings from the electron microprobe indicate the presence of gypsum/lime nodules surrounded by metallic rims mainly consisting of As, Fe, and Ni. μXRF elemental mapping confirms these EPMA results. μXAS collected within the metal-bearing rims indicates As and Fe is present mainly in the +5 and +3 oxidation state, respectively. (author)

Evolution of Acid Mine Drainage Formation in Sulphidic Mine Tailings

Directory of Open Access Journals (Sweden)

Bernhard Dold

2014-07-01

Full Text Available Sulphidic mine tailings are among the largest mining wastes on Earth and are prone to produce acid mine drainage (AMD. The formation of AMD is a sequence of complex biogeochemical and mineral dissolution processes. It can be classified in three main steps occurring from the operational phase of a tailings impoundment until the final appearance of AMD after operations ceased: (1 During the operational phase of a tailings impoundment the pH-Eh regime is normally alkaline to neutral and reducing (water-saturated. Associated environmental problems include the presence of high sulphate concentrations due to dissolution of gypsum-anhydrite, and/or effluents enriched in elements such as Mo and As, which desorbed from primary ferric hydroxides during the alkaline flotation process. (2 Once mining-related operations of the tailings impoundment has ceased, sulphide oxidation starts, resulting in the formation of an acidic oxidation zone and a ferrous iron-rich plume below the oxidation front, that re-oxidises once it surfaces, producing the first visible sign of AMD, i.e., the precipitation of ferrihydrite and concomitant acidification. (3 Consumption of the (reactive neutralization potential of the gangue minerals and subsequent outflow of acidic, heavy metal-rich leachates from the tailings is the final step in the evolution of an AMD system. The formation of multi-colour efflorescent salts can be a visible sign of this stage.

Green remediation of tailings from the mine using inorganic agents

Directory of Open Access Journals (Sweden)

Došić Aleksandar D.

2017-01-01

Full Text Available Increasing amounts of residues and waste materials coming from industrial activities in different processes have become an increasingly urgent problem for the future. The paper presents the problem of mine tailings generated in mine “Sase” (Republic of Srpska, Bosnia and Herzegovina with high metal content (Pb, Cu and Zn. Dumpsite of this tailing represents potential risk for water bodies in the vicinity of this location. Chosen treatment process was stabilization/solidification (S/S. Inorganic agents used in this study were fly ash and red mud that represent secondary industrial waste generated on locations relatively near the mine. Therefore, their application can be used as an example of a sustainable solution of regional environmental problem. Further investigations are related to the impact of various factors on metals leaching from mine tailings solidified/stabilized material using the above mentioned immobilization agents. The performance of the immobilizing procedures was examined using several leaching tests: ANS 16.1, TCLP, DIN, MWLP. The results indicated that all S/S samples can be considered as non-hazardous waste, as all leached metal concentrations met the set criteria. These results will further enable the modelling of metals behaviour during long-term leaching from treated mine tailing. The data are invaluable in terms of economically and environmentally sound management of mine tailing.

Heavy Tail Behavior of Rainfall Extremes across Germany

Science.gov (United States)

Castellarin, A.; Kreibich, H.; Vorogushyn, S.; Merz, B.

2017-12-01

Distributions are termed heavy-tailed if extreme values are more likely than would be predicted by probability distributions that have exponential asymptotic behavior. Heavy-tail behavior often leads to surprise, because historical observations can be a poor guide for the future. Heavy-tail behavior seems to be widespread for hydro-meteorological extremes, such as extreme rainfall and flood events. To date there have been only vague hints to explain under which conditions these extremes show heavy-tail behavior. We use an observational data set consisting of 11 climate variables at 1440 stations across Germany. This homogenized, gap-free data set covers 110 years (1901-2010) at daily resolution. We estimate the upper tail behavior, including its uncertainty interval, of daily precipitation extremes for the 1,440 stations at the annual and seasonal time scales. Different tail indicators are tested, including the shape parameter of the Generalized Extreme Value distribution, the upper tail ratio and the obesity index. In a further step, we explore to which extent the tail behavior can be explained by geographical and climate factors. A large number of characteristics is derived, such as station elevation, degree of continentality, aridity, measures for quantifying the variability of humidity and wind velocity, or event-triggering large-scale atmospheric situation. The link between the upper tail behavior and these characteristics is investigated via data mining methods capable of detecting non-linear relationships in large data sets. This exceptionally rich observational data set, in terms of number of stations, length of time series and number of explaining variables, allows insights into the upper tail behavior which is rarely possible given the typical observational data sets available.

Utilization of mine tailings as partial cement replacement

DEFF Research Database (Denmark)

Sigvardsen, Nina Marie; Nielsen, M.R.; Ottosen, Lisbeth M.

2017-01-01

Depositing mine tailings entail major economic costs and negative environmental impacts. Thus finding an alternative to depositing is of interest. This study focused on the use of mine tailings as partial cement replacement, thereby preventing depositing the mine tailings. At the same time......, such use would reduce the CO2 emission related to the production of cement. Mine tailings from two different mines Zinkgruvan (Sweden) and Nalunaq (Greenland) were both tested as 5 and 10 % cement replacement. All mortar specimens with mine tailings had lower compressive strength compared to a reference...... compared to a specimen containing a 10 % replacement of cement with coal fly ash, commonly used in Denmark. The compressive strength of specimens containing mine tailings exceeded the compressive strength of the specimen containing coal fly ash, indicating further the amorphous content of volcanic decent...

Estimating contaminant discharge rates from stabilized uranium tailings embankments

International Nuclear Information System (INIS)

Weber, M.F.

1986-01-01

Estimates of contaminant discharge rates from stabilized uranium tailings embankments are essential in evaluating long-term impacts of tailings disposal on groundwater resources. Contaminant discharge rates are a function of water flux through tailings covers, the mass and distribution of tailings, and the concentrations of contaminants in percolating pore fluids. Simple calculations, laboratory and field testing, and analytical and numerical modeling may be used to estimate water flux through variably-saturated tailings under steady-state conditions, which develop after consolidation and dewatering have essentially ceased. Contaminant concentrations in water discharging from the tailings depend on tailings composition, leachability and solubility of contaminants, geochemical conditions within the embankment, tailings-water interactions, and flux of water through the embankment. These concentrations may be estimated based on maximum reported concentrations, pore water concentrations, extrapolations of column leaching data, or geochemical equilibria and reaction pathway modeling. Attempts to estimate contaminant discharge rates should begin with simple, conservative calculations and progress to more-complicated approaches, as necessary

Tailings dams from the perspective of conventional dam engineering

International Nuclear Information System (INIS)

Szymanski, M.B.

1999-01-01

A guideline intended for conventional dams such as hydroelectric, water supply, flood control, or irrigation is used sometimes for evaluating the safety of a tailings dam. Differences between tailings dams and conventional dams are often substantial and, as such, should not be overlooked when applying the techniques or safety requirements of conventional dam engineering to tailings dams. Having a dam safety evaluation program developed specifically for tailings dams is essential, if only to reduce the chance of potential errors or omissions that might occur when relying on conventional dam engineering practice. This is not to deny the merits of using the Canadian Dam Safety Association Guidelines (CDSA) and similar conventional dam guidelines for evaluating the safety of tailings dams. Rather it is intended as a warning, and as a rationale underlying basic requirement of tailings dam emgineering: specific experience in tailings dams is essential when applying conventional dam engineering practice. A discussion is included that focuses on the more remarkable tailings dam safety practics. It is not addressed to a technical publications intended for such dams, or significantly different so that the use of conventional dam engineering practice would not be appropriate. The CDSA Guidelines were recently revised to include tailings dams. But incorporating tailings dams into the 1999 revision of the CDSA Guidelines is a first step only - further revision is necessary with respect to tailings dams. 11 refs., 2 tabs

Environmental assessment of remedial action at the Tuba City uranium mill tailings site, Tuba City, Arizona

Energy Technology Data Exchange (ETDEWEB)

None

1986-11-01

This document assesses and compares the environmental impacts of various alternatives for remedial action at the Tuba City uranium mill tailings site located approximately six miles east of Tuba City, Arizona. The site covers 105 acres and contains 25 acres of tailings and some of the original mill structures. The Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated properties off the site. The US Environmental Protection Agency promulgated standards for the remedial actions (40 CFR Part 192). Remedial actions must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated materials into a recontoured pile. A radon barrier would be constructed over the pile and various erosion control measures would be taken to assure the long-term stability of the pile. Another alternative which would involve moving the tailings to a new location is also assessed in this document. This alternative would generally involve greater short-term impacts and costs but would result in stabilization of the tailings at a more remote location. The no action alternative is also assessed in this document.

Environmental assessment of remedial action at the Tuba City uranium mill tailings site, Tuba City, Arizona

International Nuclear Information System (INIS)

1986-11-01

This document assesses and compares the environmental impacts of various alternatives for remedial action at the Tuba City uranium mill tailings site located approximately six miles east of Tuba City, Arizona. The site covers 105 acres and contains 25 acres of tailings and some of the original mill structures. The Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated properties off the site. The US Environmental Protection Agency promulgated standards for the remedial actions (40 CFR Part 192). Remedial actions must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated materials into a recontoured pile. A radon barrier would be constructed over the pile and various erosion control measures would be taken to assure the long-term stability of the pile. Another alternative which would involve moving the tailings to a new location is also assessed in this document. This alternative would generally involve greater short-term impacts and costs but would result in stabilization of the tailings at a more remote location. The no action alternative is also assessed in this document

Pisodonophis boro (ophichthidae: anguilliformes): specialization for head-first and tail-first burrowing?

Science.gov (United States)

De Schepper, Natalie; De Kegel, Barbara; Adriaens, Dominique

2007-02-01

The rice paddy eel, Pisodonophis boro (P. boro), is of special interest because of its peculiar burrowing habits. P. boro penetrates the substrate tail-first, a technique common for ophichthids, but it is able to burrow head-first as well. P. boro exhibits three feeding modes: inertial feeding, grasping, and spinning. Rotational feeding is a highly specialized feeding mode, adopted by several elongate, aquatic vertebrates and it is likely that some morphological modifications are related to this feeding mode. The detailed morphology of the head and tail of P. boro is examined with the goal to apportion the anatomical specializations among head-first burrowing, tail-first burrowing, and rotational feeding. The reduced eyes, covered with thick corneas may be beneficial for protection during head-first burrowing, but at the same time decreased visual acuity may have an impact on other sensory systems (e.g. cephalic lateral line system). The elongated and pointed shape of the skull is beneficial for substrate penetration. The cranial bones and their joints, which are fortified, are advantageous for resisting high mechanical loads during head-first burrowing. The aponeurotic connection between epaxial and jaw muscles is considered beneficial for transferring these forces from the body to the head during rotational feeding. Hypertrophied jaw muscles facilitate a powerful bite, which is required to hold prey during spinning movements and variability in the fiber angles of subdivisions of jaw muscles may be beneficial for preventing the lower jaw from being dislodged or opened. Furthermore, firm upper (premaxillo-ethmovomerine complex) and lower jaws (with robust coronoid processes) and high neurocranial rigidity are advantageous for a solid grip to hold prey during rotational feeding. The pointed shape of the tail and the consolidated caudal skeleton are beneficial for their tail-first burrowing habits. It is quite likely that the reduction of the caudal musculature is

Environmental Assessment of remedial action at the Ambrosia Lake uranium mill tailings site, Ambrosia Lake, New Mexico

Energy Technology Data Exchange (ETDEWEB)

1987-06-01

This document assesses and compares the environmental impacts of various alternatives for remedial action at the Ambrosia Lake uranium mill tailings site located near Ambrosia Lake, New Mexico. The designated site covers 196 acres and contains 111 acres of tailings and some of the original mill structures. The Uranium Mill Tailings Radiation Control Act (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated properties off the site. The US Environmental Protection Agency promulgated standards for th remedial action (40 CFR Part 192). Remedial action must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated materials into a recontoured pile. A radon barrier would be constructed over the pile and various erosion protection measures would be taken to assure the long-term stability of the pile. Another alternative which would involve moving the tailings to a new location is also assessed in this document. This alternative would generally involve greater short-term impacts and costs but would result in stabilization of the tailings at an undeveloped location. The no action alternative is also assessed in this document.

Environmental Assessment of remedial action at the Ambrosia Lake uranium mill tailings site, Ambrosia Lake, New Mexico

International Nuclear Information System (INIS)

1987-06-01

This document assesses and compares the environmental impacts of various alternatives for remedial action at the Ambrosia Lake uranium mill tailings site located near Ambrosia Lake, New Mexico. The designated site covers 196 acres and contains 111 acres of tailings and some of the original mill structures. The Uranium Mill Tailings Radiation Control Act (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated properties off the site. The US Environmental Protection Agency promulgated standards for th remedial action (40 CFR Part 192). Remedial action must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated materials into a recontoured pile. A radon barrier would be constructed over the pile and various erosion protection measures would be taken to assure the long-term stability of the pile. Another alternative which would involve moving the tailings to a new location is also assessed in this document. This alternative would generally involve greater short-term impacts and costs but would result in stabilization of the tailings at an undeveloped location. The no action alternative is also assessed in this document

Why are most EU pigs tail docked?

DEFF Research Database (Denmark)

D'eath, R.B.; Niemi, J.K.; Vosough Ahmadi, B.

2016-01-01

To limit tail biting incidence, most pig producers in Europe tail dock their piglets. This is despite EU Council Directive 2008/120/EC banning routine tail docking and allowing it only as a last resort. The paper aims to understand what it takes to fulfil the intentions of the Directive...... by examining economic results of four management and housing scenarios, and by discussing their consequences for animal welfare in the light of legal and ethical considerations. The four scenarios compared are: ‘Standard Docked’, a conventional housing scenario with tail docking meeting the recommendations...... for Danish production (0.7 m2/pig); ‘Standard Undocked’, which is the same as ‘Standard Docked’ but with no tail docking, ‘Efficient Undocked’ and ‘Enhanced Undocked’, which have increased solid floor area (0.9 and 1.0 m2/pig, respectively) provision of loose manipulable materials (100 and 200 g/straw per...

UMTRA -- The US Uranium Mill Tailings Remedial Action Project

International Nuclear Information System (INIS)

Lightner, R.; Cormier, C.; Bierley, D.

1995-01-01

In the late 1970s, the United States (US) established the first comprehensive regulatory structure for the management, disposal, and long-term care of wastes produced from its domestic uranium processing industry. This regulatory framework was established through the passage of the Uranium Mill Tailings Radiation Control Act of 1978, often referred to as UMTRCA. This legislation created the Uranium Mill Tailings Remedial Action (UMTRA) Project and assigned the US Department of Energy (DOE) the lead in conducting the required remedial action at 24 designated inactive uranium ore processing sites. With the majority of these 22 sites complete, the DOE's UMTRA Project has established a distinguished reputation for safely and effectively remediating these low-level waste sites in a complex regulatory and socioeconomic environment. This paper describes the past accomplishments and current status of the UMTRA Project and discusses the DOE's plans for addressing ground water contamination associated with these sites and its commitment to continuing the long-term care and management of these disposal cells

Overview of uranium mill tailings remedial action project of the United States of America 1995-1996

International Nuclear Information System (INIS)

Edge, R.

1997-01-01

From the early 1940's through the 1960's the United States federal government contracted for processed uranium ore for national defense research, weapons development and commercial nuclear energy. When these contracts were terminated, the mills ceased operation leaving large uranium tailings on the former mill sites. The purpose of the Uranium Remedial Action Project (UMTRA) is to minimize or eliminate potential health hazards resulting from exposure of the public to the tailings at these abandons sites. There are 24 inactive uranium mill tailings sites, in 10 states and an Indian reservation lands, included for clean up under the auspices of UMTRA. Presently the last 2 sites are under remediation. This paper addresses the progress of the project over the last two years. (author)

Unique structural features facilitate lizard tail autotomy.

Science.gov (United States)

Sanggaard, Kristian W; Danielsen, Carl Chr; Wogensen, Lise; Vinding, Mads S; Rydtoft, Louise M; Mortensen, Martin B; Karring, Henrik; Nielsen, Niels Chr; Wang, Tobias; Thøgersen, Ida B; Enghild, Jan J

2012-01-01

Autotomy refers to the voluntary shedding of a body part; a renowned example is tail loss among lizards as a response to attempted predation. Although many aspects of lizard tail autotomy have been studied, the detailed morphology and mechanism remains unclear. In the present study, we showed that tail shedding by the Tokay gecko (Gekko gecko) and the associated extracellular matrix (ECM) rupture were independent of proteolysis. Instead, lizard caudal autotomy relied on biological adhesion facilitated by surface microstructures. Results based on bio-imaging techniques demonstrated that the tail of Gekko gecko was pre-severed at distinct sites and that its structural integrity depended on the adhesion between these segments.

Basic description of tailings from Aitik focusing on mechanical behavior

OpenAIRE

Bhanbhro, Riaz; Knutsson, Roger; Rodriguez, Juan; Edeskär, Tommy; Knutsson, Sven

2013-01-01

Tailings are artificial granular materials that behave different as compared to natural soil of equal grain sizes. Tailings particle sizes, shapes, gradation and mechanical behavior may influence the performance of tailings dams. Hence it is essential to understand the tailings materials in depth. This article describes present studies being carried out on Aitik tailings. Basic tailings characteristics including specific gravity, phase relationships, particle sizes, particle shapes and direct...

A new procedure for deep sea mining tailings disposal

OpenAIRE

Ma, W.; Schott, D.L.; Lodewijks, G.

2017-01-01

Deep sea mining tailings disposal is a new environmental challenge related to water pollution, mineral crust waste handling, and ocean biology. The objective of this paper is to propose a new tailings disposal procedure for the deep sea mining industry. Through comparisons of the tailings disposal methods which exist in on-land mining and the coastal mining fields, a new tailings disposal procedure, i.e., the submarine–backfill–dam–reuse (SBDR) tailings disposal procedure, is proposed. It com...

Environmental assessment of remedial action at the Slick Rock uranium mill tailings sites, Slick Rock, Colorado

International Nuclear Information System (INIS)

1995-01-01

The Uranium Mill Tailings Radiation Control Act of 1978, hereafter referred to as the UMTRCA, authorized the US Department of Energy (DOE) to clean up two uranium mill tailings processing sites near Slick Rock, Colorado, in San Miguel County. The purpose of the cleanup is to reduce the potential health effects associated with the radioactive materials remaining on the processing sites and on vicinity properties (VPs) associated with the sites. The US Environmental Protection Agency (EPA) promulgated standards for the UMTRCA that contained measures to control the contaminated materials and to protect the ground water from further degradation. The sites contain concrete foundations of mill buildings, tailings piles, and areas contaminated by windblown and waterborne radioactive tailings materials. The proposed action is to remediate the UC and NC sites by removing all contaminated materials within the designated site boundaries or otherwise associated with the sites, and relocating them to, and stabilizing them at, a location approximately 5 road mi (8 km) northeast of the processing sites on land administered by the US Bureau of Land Management (BLM). Remediation would be performed by the DOE's Uranium Mill Tailings Remedial Action (UMTRA) Project

Environmental assessment of remedial action at the Slick Rock uranium mill tailings sites, Slick Rock, Colorado

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-01-01

The Uranium Mill Tailings Radiation Control Act of 1978, hereafter referred to as the UMTRCA, authorized the US Department of Energy (DOE) to clean up two uranium mill tailings processing sites near Slick Rock, Colorado, in San Miguel County. The purpose of the cleanup is to reduce the potential health effects associated with the radioactive materials remaining on the processing sites and on vicinity properties (VPs) associated with the sites. The US Environmental Protection Agency (EPA) promulgated standards for the UMTRCA that contained measures to control the contaminated materials and to protect the ground water from further degradation. The sites contain concrete foundations of mill buildings, tailings piles, and areas contaminated by windblown and waterborne radioactive tailings materials. The proposed action is to remediate the UC and NC sites by removing all contaminated materials within the designated site boundaries or otherwise associated with the sites, and relocating them to, and stabilizing them at, a location approximately 5 road mi (8 km) northeast of the processing sites on land administered by the US Bureau of Land Management (BLM). Remediation would be performed by the DOE`s Uranium Mill Tailings Remedial Action (UMTRA) Project.

Evolution of uranium distribution and speciation in mill tailings, COMINAK Mine, Niger

International Nuclear Information System (INIS)

Déjeant, Adrien; Galoisy, Laurence; Roy, Régis; Calas, Georges; Boekhout, Flora; Phrommavanh, Vannapha; Descostes, Michael

2016-01-01

This study investigated the evolution of uranium distribution and speciation in mill tailings from the COMINAK mine (Niger), in production since 1978. A multi-scale approach was used, which combined high resolution remote sensing imagery, ICP-MS bulk rock analyses, powder X-ray diffraction, Scanning Electron Microscopy, Focused Ion Beam — Transmission Electron Microscopy and X-ray Absorption Near Edge Spectroscopy. Mineralogical analyses showed that some ore minerals, including residual uraninite and coffinite, undergo alteration and dissolution during tailings storage. The migration of uranium and other contaminants depends on (i) the chemical stability of secondary phases and sorbed species (dissolution and desorption processes), and (ii) the mechanical transport of fine particles bearing these elements. Uranium is stabilized after formation of secondary uranyl sulfates and phosphates, and adsorbed complexes on mineral surfaces (e.g. clay minerals). In particular, the stock of insoluble uranyl phosphates increases with time, thus contributing to the long-term stabilization of uranium. At the surface, a sulfate-cemented duricrust is formed after evaporation of pore water. This duricrust limits water infiltration and dust aerial dispersion, though it is enriched in uranium and many other elements, because of pore water rising from underlying levels by capillary action. Satellite images provided a detailed description of the tailings pile over time and allow monitoring of the chronology of successive tailings deposits. Satellite images suggest that uranium anomalies that occur at deep levels in the pile are most likely former surface duricrusts that have been buried under more recent tailings. - Highlights: • The evolution of U distribution and speciation in mill tailings is investigated. • High resolution satellite images provide useful information on tailings evolution. • U and many other elements are enriched in a sulfate-rich duricrust. • Formation of

Evolution of uranium distribution and speciation in mill tailings, COMINAK Mine, Niger

Energy Technology Data Exchange (ETDEWEB)

Déjeant, Adrien, E-mail: adrien.dejeant@normalesup.org [Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Case 115, 4 place Jussieu, 75005 Paris (France); Université Paris Diderot — Paris VII, 5 rue Thomas Mann, 75013 Paris (France); Galoisy, Laurence [Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Case 115, 4 place Jussieu, 75005 Paris (France); Université Pierre et Marie Curie — Paris VI, 4 place Jussieu, 75005 Paris (France); Roy, Régis [AREVA Mines — Geoscience Department, Tour AREVA, 1 place Jean Millier, 92084 Paris, La Défense (France); Calas, Georges; Boekhout, Flora [Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Case 115, 4 place Jussieu, 75005 Paris (France); Université Pierre et Marie Curie — Paris VI, 4 place Jussieu, 75005 Paris (France); Phrommavanh, Vannapha; Descostes, Michael [AREVA Mines — R& D Department, BAL 0414C-2, Tour AREVA, 1 place Jean Millier, 92084 Paris, La Défense (France)

2016-03-01

This study investigated the evolution of uranium distribution and speciation in mill tailings from the COMINAK mine (Niger), in production since 1978. A multi-scale approach was used, which combined high resolution remote sensing imagery, ICP-MS bulk rock analyses, powder X-ray diffraction, Scanning Electron Microscopy, Focused Ion Beam — Transmission Electron Microscopy and X-ray Absorption Near Edge Spectroscopy. Mineralogical analyses showed that some ore minerals, including residual uraninite and coffinite, undergo alteration and dissolution during tailings storage. The migration of uranium and other contaminants depends on (i) the chemical stability of secondary phases and sorbed species (dissolution and desorption processes), and (ii) the mechanical transport of fine particles bearing these elements. Uranium is stabilized after formation of secondary uranyl sulfates and phosphates, and adsorbed complexes on mineral surfaces (e.g. clay minerals). In particular, the stock of insoluble uranyl phosphates increases with time, thus contributing to the long-term stabilization of uranium. At the surface, a sulfate-cemented duricrust is formed after evaporation of pore water. This duricrust limits water infiltration and dust aerial dispersion, though it is enriched in uranium and many other elements, because of pore water rising from underlying levels by capillary action. Satellite images provided a detailed description of the tailings pile over time and allow monitoring of the chronology of successive tailings deposits. Satellite images suggest that uranium anomalies that occur at deep levels in the pile are most likely former surface duricrusts that have been buried under more recent tailings. - Highlights: • The evolution of U distribution and speciation in mill tailings is investigated. • High resolution satellite images provide useful information on tailings evolution. • U and many other elements are enriched in a sulfate-rich duricrust. • Formation of

Ilmenite Mineral's Recovery from Beach Sand Tailings

International Nuclear Information System (INIS)

Mulaba-Bafubiandi, Antoine F.; Mukendi-Ngalula, David; Waanders, Frans B.

2002-01-01

The mineral ilmenite is the major source of rutile for industrial use and is of interest to paint and fertiliser industries. Enormous unutilised tailing dams lie on the eastern coast of the South Africa. Although covered by a simulation of the original indigenous vegetation, these tailings are still ilmenite bearing and of economic value. Tailings emanating from beach sand mineral slimes dams of the Kwazulu-Natal area (South Africa) have been processed. Screening, flotation, spiral concentration and magnetic separation methods were used either separately or successively. The present work sheds light on alternative routes for the extraction of the ilmenite, from these tailings. It moreover points out the usefulness of the Moessbauer spectroscopy in the mineral processing product monitoring. Tailings from the beach sands were used in the present study after the economic industrial minerals zirconia, ilmenite and rutile had been extracted in previous mining operations. About 61% natural ilmenite recovery was observed in the flotation concentrate of a Humphrey Spiral concentrate while a 62% recovery of hematite was found in the flotation tailings. The combination of screening, spiral concentration and magnetic separation, and flotation yielded a product with the highest ilmenite and hematite concentration being 71% and 19%, respectively. A natural ilmenite mineral, containing 87% ilmenite and 13% hematite, could be produced and extracted from the tailings of the flotation process, collected subsequently to the spiral concentration and the initial screening.

Efficient bootstrap estimates for tail statistics

Science.gov (United States)

Breivik, Øyvind; Aarnes, Ole Johan

2017-03-01

Bootstrap resamples can be used to investigate the tail of empirical distributions as well as return value estimates from the extremal behaviour of the sample. Specifically, the confidence intervals on return value estimates or bounds on in-sample tail statistics can be obtained using bootstrap techniques. However, non-parametric bootstrapping from the entire sample is expensive. It is shown here that it suffices to bootstrap from a small subset consisting of the highest entries in the sequence to make estimates that are essentially identical to bootstraps from the entire sample. Similarly, bootstrap estimates of confidence intervals of threshold return estimates are found to be well approximated by using a subset consisting of the highest entries. This has practical consequences in fields such as meteorology, oceanography and hydrology where return values are calculated from very large gridded model integrations spanning decades at high temporal resolution or from large ensembles of independent and identically distributed model fields. In such cases the computational savings are substantial.

Self-consistent theory of three-dimensional convection in the geomagnetic tail

International Nuclear Information System (INIS)

Birn, J.; Schindler, K.

1983-01-01

The self-consistent theory of time-dependent convection in the earth's magnetotail of Schindler and Birn (1982) is extended to three dimensions to include more realistic tail geometry and three-dimensional flow. We confirm that a steady state solution implies unrealistic tail geometry or large particle or energy losses that are unrealistic during quiet times and conclude therefore that as in the 2-dimensional case the magnetotail becomes time-dependent for typical convection electric fields. Explicit solutions are derived, even analytically, for the three-dimensional flow and the electric and magnetic field in a realistic tail geometry, and quantitative examples are presented. Consequences of time-dependent convection are demonstrated considering two idealized cases of magnetosphere response to solar wind changes: (1) uniform compression as the likely consequence of increasing (static, dynamic or magnetic) solar wind pressure; and (2) compression only in the z direction perpendicular to the plasma sheet as the probable consequence of a dawn to dusk external electric field (E/sub y/>0), corresponding to a southward interplanetary magnetic field component (B/sub z/ 0 with geomagnetic activity. Several other features, already present in the 2-dimensional theory, are confirmed

Chaperone role for proteins p618 and p892 in the extracellular tail development of Acidianus two-tailed virus

DEFF Research Database (Denmark)

Scheele, Urte; Erdmann, Susanne; Ungewickell, Ernst J.

2011-01-01

The crenarchaeal Acidianus two-tailed virus (ATV) undergoes a remarkable morphological development, extracellularly and independently of host cells, by growing long tails at each end of a spindle-shaped virus particle. Initial work suggested that an intermediate filament-like protein, p800...... the interactions observed between the different protein and DNA components and to explain their possible structural and functional roles in extracellular tail development....

Fat-tailed distributions data, diagnostics and dependence

CERN Document Server

Cooke, Roger M; Misiewicz, Jolanta

2014-01-01

This title is written for the numerate nonspecialist, and hopes to serve three purposes. First it gathers mathematical material from diverse but related fields of order statistics, records, extreme value theory, majorization, regular variation and subexponentiality. All of these are relevant for understanding fat tails, but they are not, to our knowledge, brought together in a single source for the target readership. Proofs that give insight are included, but for most fussy calculations the reader is referred to the excellent sources referenced in the text. Multivariate extremes are not treated. This allows us to present material spread over hundreds of pages in specialist texts in twenty pages. Chapter 5 develops new material on heavy tail diagnostics and gives more mathematical detail. Since variances and covariances may not exist for heavy tailed joint distributions, Chapter 6 reviews dependence concepts for certain classes of heavy tailed joint distributions, with a view to regressing heavy tailed variabl...

An analysis of factors related to the tail-like pattern of myxofibrosarcoma seen on MRI

International Nuclear Information System (INIS)

Kikuta, Kazutaka; Kubota, Daisuke; Chuuman, Hirokazu; Kawai, Akira; Yoshida, Akihiko; Morioka, Hideo; Toyama, Yoshiaki

2015-01-01

Myxofibrosarcoma (MFS) is characterized by a high frequency of local recurrence after surgery because of infiltrative growth of the tumor cells. This infiltrative growth creates a characteristic 'tail-like' pattern on magnetic resonance imaging (MRI), and it has been reported that this pattern is especially obvious on gadolinium-enhanced MRI (Gd MRI). However, the relationship between the tail-like pattern seen on Gd MRI and clinicopathological features of MFS is still not clear. In this study, we performed a retrospective analysis to identify clinicopathological factors related to the tail-like pattern of the MRI findings in patients with MFS. We retrospectively analyzed 50 patients with MFS to identify factors related to the tail-like pattern. On Gd MRI, 32 of the 50 patients presented the tail-like pattern, whereas 18 presented a solid pattern. The clincopathological factors related to the tail-like pattern were evaluated by chi-squared test. A superficial origin (p = 0.0009) was most significantly related to the tail-like pattern. The 5-year recurrence-free survival (RFS) rate was 75.6 % for patients showing the tail-like pattern and 90.9 % for those showing the solid pattern. The corresponding 5-year disease-free survival (DFS) rates were 64.7 and 79.3 %, respectively. Thus in terms of both 5-year RFS and DFS, patients with the tail-like pattern tended to have a poorer outcome. A superficial origin of MFS is significantly related to a tail-like pattern on Gd MRI. The tail-like pattern is associated with poorer prognosis. Further studies of tumor depth and the tail-like pattern on Gd MRI are needed. (orig.)

Leaching characteristics of vanadium in mine tailings and soils near a vanadium titanomagnetite mining site

Energy Technology Data Exchange (ETDEWEB)

Yang, Jinyan; Tang, Ya; Yang, Kai [College of Architecture and Environment, Sichuan University, Chengdu 610065 (China); Rouff, Ashaki A. [School of Earth and Environmental Sciences, Queens College City University of New York, 65-30 Kissena Boulevard, Flushing, NY 11367 (United States); Elzinga, Evert J. [Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ (United States); Huang, Jen-How, E-mail: jen-how.huang@unibas.ch [Institute of Environmental Geosciences, University of Basel, CH-4056 Basel (Switzerland)

2014-01-15

Highlights: • Vanadium in the soil and mine tailings has low solubility. • The leachability of vanadium in the mine tailings is lower than in the soil. • Low risk of vanadium migrating from the soil and mine tailings into the surrounding environment. • Drought and rewetting increase vanadium release from the soil and mine tailings. • Soil leaching processes control vanadium transport in soils overlain with mine tailings. -- Abstract: A series of column leaching experiments were performed to understand the leaching behaviour and the potential environmental risk of vanadium in a Panzhihua soil and vanadium titanomagnetite mine tailings. Results from sequential extraction experiments indicated that the mobility of vanadium in both the soil and the mine tailings was low, with <1% of the total vanadium readily mobilised. Column experiments revealed that only <0.1% of vanadium in the soil and mine tailing was leachable. The vanadium concentrations in the soil leachates did not vary considerably, but decreased with the leachate volume in the mine tailing leachates. This suggests that there was a smaller pool of leachable vanadium in the mine tailings compared to that in the soil. Drought and rewetting increased the vanadium concentrations in the soil and mine tailing leachates from 20 μg L{sup −1} to 50–90 μg L{sup −1}, indicating the potential for high vanadium release following periods of drought. Experiments with soil columns overlain with 4, 8 and 20% volume mine tailings/volume soil exhibited very similar vanadium leaching behaviour. These results suggest that the transport of vanadium to the subsurface is controlled primarily by the leaching processes occurring in soils.

Longitudinal analysis reveals characteristically high proportions of bacterial vaginosis-associated bacteria and temporal variability of vaginal microbiota in northern pig-tailed macaques (Macaca leonina).

Science.gov (United States)

Zhu, Lin; Lei, Ai-Hua; Zheng, Hong-Yi; Lyu, Long-Bao; Zhang, Zhi-Gang; Zheng, Yong-Tang

2015-09-18

The complex and dynamic vaginal microbial ecosystem is critical to both health and disease of the host. Studies focusing on how vaginal microbiota influences HIV-1 infection may face limitations in selecting proper animal models. Given that northern pig-tailed macaques (Macaca leonina) are susceptible to HIV-1 infection, they may be an optimal animal model for elucidating the mechanisms by which vaginal microbiota contributes to resistance and susceptibility to HIV-1 infection. However, little is known about the composition and temporal variability of vaginal microbiota of the northern pig-tailed macaque. Here, we present a comprehensive catalog of the composition and temporal dynamics of vaginal microbiota of two healthy northern pig-tailed macaques over 19 weeks using 454-pyrosequencing of 16S rRNA genes. We found remarkably high proportions of a diverse array of anaerobic bacteria associated with bacterial vaginosis. Atopobium and Sneathia were dominant genera, and interestingly, we demonstrated the presence of Lactobacillus-dominated vaginal microbiota. Moreover, longitudinal analysis demonstrated that the temporal dynamics of the vaginal microbiota were considerably individualized. Finally, network analysis revealed that vaginal pH may influence the temporal dynamics of the vaginal microbiota, suggesting that inter-subject variability of vaginal bacterial communities could be mirrored in inter-subject variation in correlation profiles of species with each other and with vaginal pH over time. Our results suggest that the northern pig-tailed macaque could be an ideal animal model for prospective investigation of the mechanisms by which vaginal microbiota influence susceptibility and resistance to HIV-1 infection in the context of highly polymicrobial and Lactobacillus-dominated states.

UTAP, U Tailings Assessment Program

International Nuclear Information System (INIS)

Holmes, Ron

1998-01-01

1 - Description of program or function: UTAP carries out probabilistic analyses of the behaviour and environmental effects of uranium mill tailings, following close-out of milling operations. The models have been designed to allow predictions to be made for distances up to 50 kilometers in all directions from the tailings area. The models include features which include the ability to incorporate different receptors and site characteristics and to deal with input parameters which vary with time. 2 - Method of solution: UTAP is composed of a number of modules. These may be classified as either component or control modules. Component modules (or models) are the programs directly concerned with the simulation of a uranium tailings physical system; that is the computer implementation of the mathematical models representing the uranium tailings pile and surrounding environment. Control modules provide the infrastructure for probabilistic analysis using the component modules. These functions include probabilistic sampling of input parameters such as constant, normal, log-normal, uniform, log-uniform, triangular, Weibull, Beta, arbitrary and correlated. The sampling method used is straight Monte Carlo. The radionuclides modelled are: natural uranium, total thorium, radium-226, radon-222 and lead-210. The pH of the reference uranium tailings site and a chained river-lake system are also modelled. For the afore- mentioned radionuclides the following pathways of dose to the receptors modelled: water consumption, fish consumption, radon inhalation, dust inhalation, vegetable consumption, animal produce consumption and ground-shine. 3 - Restrictions on the complexity of the problem: The maximum number of steps through time allowed is 300

Unique structural features facilitate lizard tail autotomy.

Directory of Open Access Journals (Sweden)

Kristian W Sanggaard

Full Text Available Autotomy refers to the voluntary shedding of a body part; a renowned example is tail loss among lizards as a response to attempted predation. Although many aspects of lizard tail autotomy have been studied, the detailed morphology and mechanism remains unclear. In the present study, we showed that tail shedding by the Tokay gecko (Gekko gecko and the associated extracellular matrix (ECM rupture were independent of proteolysis. Instead, lizard caudal autotomy relied on biological adhesion facilitated by surface microstructures. Results based on bio-imaging techniques demonstrated that the tail of Gekko gecko was pre-severed at distinct sites and that its structural integrity depended on the adhesion between these segments.

Ecological restoration alters microbial communities in mine tailings profiles.

Science.gov (United States)

Li, Yang; Jia, Zhongjun; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

2016-04-29

Ecological restoration of mine tailings have impact on soil physiochemical properties and microbial communities. The surface soil has been a primary concern in the past decades, however it remains poorly understood about the adaptive response of microbial communities along the profile during ecological restoration of the tailings. In this study, microbial communities along a 60-cm profile were investigated in a mine tailing pond during ecological restoration of the bare waste tailings (BW) with two vegetated soils of Imperata cylindrica (IC) and Chrysopogon zizanioides (CZ) plants. Revegetation of both IC and CZ could retard soil degradation of mine tailing by stimulation of soil pH at 0-30 cm soils and altered the bacterial communities at 0-20 cm depths of the mine tailings. Significant differences existed in the relative abundance of the phyla Alphaproteobacteria, Deltaproteobacteria, Acidobacteria, Firmicutes and Nitrospira. Slight difference of bacterial communities were found at 30-60 cm depths of mine tailings. Abundance and activity analysis of nifH genes also explained the elevated soil nitrogen contents at the surface 0-20 cm of the vegetated soils. These results suggest that microbial succession occurred primarily at surface tailings and vegetation of pioneering plants might have promoted ecological restoration of mine tailings.

Ecological restoration alters microbial communities in mine tailings profiles

Science.gov (United States)

Li, Yang; Jia, Zhongjun; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

2016-04-01

Ecological restoration of mine tailings have impact on soil physiochemical properties and microbial communities. The surface soil has been a primary concern in the past decades, however it remains poorly understood about the adaptive response of microbial communities along the profile during ecological restoration of the tailings. In this study, microbial communities along a 60-cm profile were investigated in a mine tailing pond during ecological restoration of the bare waste tailings (BW) with two vegetated soils of Imperata cylindrica (IC) and Chrysopogon zizanioides (CZ) plants. Revegetation of both IC and CZ could retard soil degradation of mine tailing by stimulation of soil pH at 0-30 cm soils and altered the bacterial communities at 0-20 cm depths of the mine tailings. Significant differences existed in the relative abundance of the phyla Alphaproteobacteria, Deltaproteobacteria, Acidobacteria, Firmicutes and Nitrospira. Slight difference of bacterial communities were found at 30-60 cm depths of mine tailings. Abundance and activity analysis of nifH genes also explained the elevated soil nitrogen contents at the surface 0-20 cm of the vegetated soils. These results suggest that microbial succession occurred primarily at surface tailings and vegetation of pioneering plants might have promoted ecological restoration of mine tailings.

Wake patterns of the wings and tail of hovering hummingbirds

Science.gov (United States)

Altshuler, Douglas L.; Princevac, Marko; Pan, Hansheng; Lozano, Jesse

The flow fields of slowly flying bats and fasterflying birds differ in that bats produce two vortex loops during each stroke, one per wing, and birds produce a single vortex loop per stroke. In addition, the circulation at stroke transition approaches zero in bats but remains strong in birds. It is unknown if these difference derive from fundamental differences in wing morphology or are a consequence of flight speed. Here, we present an analysis of the horizontal flow field underneath hovering Anna's hummingbirds (Calypte anna) to describe the wake of a bird flying at zero forward velocity. We also consider how the hummingbird tail interacts with the wake generated by the wings. High-speed image recording and analysis from three orthogonal perspectives revealed that the wing tips reach peak velocities in the middle of each stroke and approach zero velocity at stroke transition. Hummingbirds use complex tail kinematic patterns ranging from in phase to antiphase cycling with respect to the wings, covering several phase shifted patterns. We employed particle image velocimetry to attain detailed horizontal flow measurements at three levels with respect to the tail: in the tail, at the tail tip, and just below the tail. The velocity patterns underneath the wings indicate that flow oscillates along the ventral-dorsal axis in response to the down- and up-strokes and that the sideways flows with respect to the bird are consistently from the lateral to medial. The region around the tail is dominated by axial flows in dorsal to ventral direction. We propose that these flows are generated by interaction between the wakes of the two wings at the end of the upstroke, and that the tail actively defects flows to generate moments that contribute to pitch stability. The flow fields images also revealed distinct vortex loops underneath each wing, which were generated during each stroke. From these data, we propose a model for the primary flow structures of hummingbirds that more

Geodesic acoustic mode driven by energetic particles with bump-on-tail distribution

Science.gov (United States)

Ren, Haijun; Wang, Hao

2018-04-01

Energetic-particle-driven geodesic acoustic mode (EGAM) is analytically investigated by adopting the bump-on-tail distribution for energetic particles (EPs), which is created by the fact that the charge exchange time (τcx ) is sufficiently shorter than the slowing down time (τsl ). The dispersion relation is derived in the use of gyro-kinetic equations. Due to the finite ratio of the critical energy and the initial energy of EPs, defined as τc , the dispersion relation is numerically evaluated and the effect of finite τc is examined. Following relative simulation and experimental work, we specifically considered two cases: τsl/τcx = 3.4 and τsl/τcx = 20.4 . The pitch angle is shown to significantly enhance the growth rate and meanwhile, the real frequency is dramatically decreased with increasing pitch angle. The excitation of high-frequency EGAM is found, and this is consistent with both the experiment and the simulation. The number density effect of energetic particles, represented by \

A proactive approach to sustainable management of mine tailings

Science.gov (United States)

Edraki, Mansour; Baumgartl, Thomas

2015-04-01

The reactive strategies to manage mine tailings i.e. containment of slurries of tailings in tailings storage facilities (TSF's) and remediation of tailings solids or tailings seepage water after the decommissioning of those facilities, can be technically inefficient to eliminate environmental risks (e.g. prevent dispersion of contaminants and catastrophic dam wall failures), pose a long term economic burden for companies, governments and society after mine closure, and often fail to meet community expectations. Most preventive environmental management practices promote proactive integrated approaches to waste management whereby the source of environmental issues are identified to help make a more informed decisions. They often use life cycle assessment to find the "hot spots" of environmental burdens. This kind of approach is often based on generic data and has rarely been used for tailings. Besides, life cycle assessments are less useful for designing operations or simulating changes in the process and consequent environmental outcomes. It is evident that an integrated approach for tailings research linked to better processing options is needed. A literature review revealed that there are only few examples of integrated approaches. The aim of this project is to develop new tailings management models by streamlining orebody characterization, process optimization and rehabilitation. The approach is based on continuous fingerprinting of geochemical processes from orebody to tailings storage facility, and benchmark the success of such proactive initiatives by evidence of no impacts and no future projected impacts on receiving environments. We present an approach for developing such a framework and preliminary results from a case study where combined grinding and flotation models developed using geometallurgical data from the orebody were constructed to predict the properties of tailings produced under various processing scenarios. The modelling scenarios based on the

Studies of red soils as capping the uranium mill tailing impoundments

International Nuclear Information System (INIS)

Wen Zhijian; Chen Zhangru; Liu Zhengyi; Chen Guoliang

2001-01-01

Capping is one of the important technical engineering measures to assure the long term stabilization and isolation of uranium mill tailings. This paper reports in situ surveys of radon emanations before and after tailings slurries were capped with local red soils at the uranium mill tailings. The data obtained by soil-gas surveys reveal that radon emanation decreased with an increase in capping thickness. The dry density of the capping materials also plays an important role in preventing radon emanation. The measurement results show that utilizing high densities of red soils as capping materials can significantly decrease the required thickness of the capping. The analytical results from borehole red soil samples show that uranium, thorium, and radium contents are consistent with the regional environmental radioactivity level. The studies of the mineralogical composition indicate that the local red soils are rich in clay minerals, e.g. kaolinite, illite and mica vermiculite mixed-layer minerals, which would play an active role in preventing radionuclide release to the surrounding environment. A conceptual model for remediation of south China's uranium mill tailing has been developed

Effects of tail docking and docking length on neuroanatomical changes in healed tail tips of pigs

DEFF Research Database (Denmark)

Herskin, M S; Thodberg, K; Jensen, Henrik Elvang

2015-01-01

% (n=19); or leaving 25% (n=11) of the tail length on the pigs. The piglets were docked between day 2 and 4 after birth using a gas-heated apparatus, and were kept under conventional conditions until slaughter at 22 weeks of age, where tails were removed and examined macroscopically and histologically...

Oil sands tailings technology : understanding the impact to reclamation

Energy Technology Data Exchange (ETDEWEB)

Mamer, M. [Suncor Energy Inc., Fort McMurray, AB (Canada)

2010-07-01

This paper discussed tailings management techniques at oil sands mines and their effects on reclamation schedules and outcomes. The layer of mature fine tailings (MFT) that forms in tailings ponds does not settle within a reasonable time frame, requiring more and larger tailings ponds for storing MFT. Consolidated tailings (CT) technology was developed to accelerate the consolidation of MFT, although the process nonetheless takes decades. CT is produced from mixing tailings sand, gypsum, and MFT to create a mixture that will consolidate more quickly and release water. However, CT production is tied to the extraction process, making it applicable only when the plant is operational, and a precise recipe and accurate injection are required for CT to work. In tailings reduction operations (TRO), a new approach to tailings management, MFT is mixed with a polymer flocculant, deposited in thin layers, and allowed to dry. TRO has a significant advantage over CT in that the latter takes up to 30 years to consolidate to a trafficable surface compared to weeks for TRO. TRO allows MFT to be consumed more quickly than it is produced, reducing need to build more tailings ponds, operates independent of plant operations, accelerates the reclamation time frame, and offers enhanced flexibility in final tailings placement sites. TRO also creates a dry landscape, to which well established reclamation techniques can be applied. Dried MFT is a new material type, and research is exploring optimum reclamation techniques. 2 figs.

Reclamation of copper mine tailings using sewage sludge

OpenAIRE

Stjernman Forsberg, Lovisa

2008-01-01

Tailings are the fine-grained fraction of waste produced during mining operations. This work was carried out on tailings from the Aitik copper mine in northern Sweden. Establishment of vegetation on the Aitik mine tailings deposit is planned to take place at closure of the mine, using sewage sludge as fertiliser. However, the tailings contain traces of metal sulphides, e.g. pyrite, FeS2, and chalcopyrite, CuFeS2. When the sulphides are oxidised, they start to weather and release metals and st...

Processes for extracting radium from uranium mill tailings

International Nuclear Information System (INIS)

Nirdosh, I.; Baird, M.H.; Muthuswami, S.V.

1987-01-01

This patent describes a process for the extraction of radium from uranium mill tailings solids including the steps of contacting the tailings with a liquid leaching agent, leaching the tailings therewith and subsequently separating the leachate liquid and the leached solids. The improvement described here is wherein the leaching agent comprises: (a) a complexing agent in an amount of from 2 to 10 times the stoichiometric amount needed to complex the metal ions to be removed thereby from the tailings; and (b) a reducing agent reducing the hydrolysable ions of the metal ions to be removed to their lower oxidation states, the reduction agent being present in an amount from 2 to 10 times the stoichiometric amount needed for reducing the hydrolysable metals present in the tailings

Field experiment on 222Rn flux from reclaimed uranium tailings

International Nuclear Information System (INIS)

Hinton, T.G.

1983-01-01

Design and construction techniques are described for a 1.6 ha experimental uranium mill tailings reclamation plot. A passive, activated charcoal device was developed and tested for measurements of radon flux. Experiments on radon flux versus overburden depth showed that tailings covered with 1.5 m of revegetated or 0.3 m of bare overburden had exhalation rates comparable to background. Vegetated subplots exhibited a significantly higher (often an order of magnitude) flux than the bare subplots. Results on the variation of flux over time did not reveal any definitive patterns, possibly due to the high variability among replicates. A positive correlation was demonstrated between precipitation and radon flux. This is discussed in detail and possibly explained by the increase in water content of the micropores within the tailings, which increases the emanation coefficient without adversely effecting the diffusion coefficient of the overburden. 30 references, 7 figures, 3 tables

APPLICATION OF POSTFLOTATION TAILINGS IN HYDROENGINEERING STRUCTURES

Directory of Open Access Journals (Sweden)

Katarzyna Stefaniak

2017-01-01

Full Text Available Economic development stimulated by the increased demand for production of consumer goods and the growing human population result in increasing amounts of various wastes, including tailings. The mining industry in Poland, comprising also mining of non-ferrous metal ores, is a strategic branch of the national economy and at the same time a leading waste producer. Tailings management is a significant problem both in Poland and worldwide. Frequently considerable amounts of wastes are accumulated in mine spoil tips, in areas not always suitable for their deposition, thus leading to the degradation of the surrounding environment. At the huge volume of produced wastes their rational and economically viable management is becoming crucial. On the other hand, depletion of natural aggregate deposits is an important incentive to search for substitutes, which would be suitable for the development of road infrastructure or which could be used in earth structure engineering to construct hydroengineering objects. Since no profitable recovery technologies are available at present, tailings generated by copper mining are deposited in tailings storage facilities. The largest and at the same time the only currently operating facility in Poland is the Żelazny Most Mining Tailings Storage Facility, belonging to KGHM Polska Miedź S.A. The paper presents criteria for material quality and density imposed on the material embedded in the static core of the tailings pond dam. For this purpose studies were conducted to confirm applicability of sorted tailings as a material for the construction of earth structures.

PARAMETRIC DISTRIBUTION FAMILIES USEFUL FOR MODELLING NON - LIFE INSURANCE PAYMENTS DATA. TAIL BEHAVIOUR

Directory of Open Access Journals (Sweden)

Sandra Teodorescu

2013-11-01

Full Text Available The present paper describes a series of parametric distributions used for modeling non-life insurance payments data.Of those listed, special attention is paid to the transformed Beta distribution family.This distribution as well as those which are obtained from it(special cases of four-parameter transformed Beta distribution are used in the modeling of high costs, or even extreme ones.In the literature it follows the tail behaviour of distributions depending on the parameters, because the insurance payments data are tipically highly positively skewed and distributed with large upper tails.In the paper is described the tail behavior of the distribution in the left and right side respectively, and deduced from it, a general case.There are also some graphs of probability density function for one of the transformed Beta family members, which comes to reinforce the comments made.

Predicting Tail Buffet Loads of a Fighter Airplane

Science.gov (United States)

Moses, Robert W.; Pototzky, Anthony S.

2006-01-01

Buffet loads on aft aerodynamic surfaces pose a recurring problem on most twin-tailed fighter airplanes: During maneuvers at high angles of attack, vortices emanating from various surfaces on the forward parts of such an airplane (engine inlets, wings, or other fuselage appendages) often burst, immersing the tails in their wakes. Although these vortices increase lift, the frequency contents of the burst vortices become so low as to cause the aft surfaces to vibrate destructively. Now, there exists a new analysis capability for predicting buffet loads during the earliest design phase of a fighter-aircraft program. In effect, buffet pressures are applied to mathematical models in the framework of a finite-element code, complete with aeroelastic properties and working knowledge of the spatiality of the buffet pressures for all flight conditions. The results of analysis performed by use of this capability illustrate those vibratory modes of a tail fin that are most likely to be affected by buffet loads. Hence, the results help in identifying the flight conditions during which to expect problems. Using this capability, an aircraft designer can make adjustments to the airframe and possibly the aerodynamics, leading to a more robust design.

High energy P implants in silicon

International Nuclear Information System (INIS)

Raineri, V.; Cacciato, A.; Benyaich, F.; Priolo, F.; Rimini, E.; Galvagno, G.; Capizzi, S.

1992-01-01

Phosphorus ions in the energy range 0.25-1 MeV and in the dose range 2x10 13 -1x10 15 P/cm 2 were implanted into (100) Si single crystal at different tilt angles. In particular channeling and random conditions were investigated. For comparison some implants were performed on samples with a 2 μm thick surface amorphous layer. Chemical concentration P profiles were obtained by secondary ion mass spectrometry. Carrier concentration and mobility profile measurements were carried out by sheet resistance and Hall measurements on implanted van der Pauw patterns. Carrier concentration profiles were also obtained by spreading resistance (SR) measurements. The damage in the as-implanted samples was determined by backscattering and channeling spectrometry (RBS) as a function of the dose and implantation energy. Comparison of random implants in crystal with implants in amorphous layers shows that in the first case it is impossible to completely avoid the channeling tail. In the implants performed under channeling conditions at low doses the P profiles are flat over more than 2 μm thick layers. Furthermore, by increasing the implanted dose, the shape of the profiles dramatically changes due to the dechanneling caused by the crystal disorder. The data are discussed and compared with Monte Carlo simulations using the MARLOWE code. A simple description of the electronic energy loss provides an excellent agreement between the calculated and experimental profiles. (orig.)

Fat-tailed risk about climate change and climate policy

International Nuclear Information System (INIS)

Hwang, In Chang; Tol, Richard S.J.; Hofkes, Marjan W.

2016-01-01

This paper investigates the role of emissions control in welfare maximization under fat-tailed risk about climate change. We provide a classification of fat tails and discuss the effect of fat-tailed risk on climate policy. One of the main findings is that emissions control may prevent the “strong” tail-effect from arising, at least under some conditions such as bounded temperature increases, low risk aversion, low damage costs, and bounded utility function. More specifically, the fat-tailed risk with respect to a climate parameter does not necessarily lead to an unbounded carbon tax. In this case, the basic principle of cost-benefit analysis maintains its applicability. - Highlights: • A fat tail is classified and the tail effect on climate policy is discussed. • The optimal carbon tax is not necessarily unbounded. • The basic principle of cost-benefit analysis maintains its applicability. • This is a numerical confirmation of the recent theoretical research.

Impact of flocculation on flotation tailing's hydro-cycloning properties

Directory of Open Access Journals (Sweden)

Knežević Dinko N.

2014-01-01

Full Text Available Research results of hydro-cycloning of flocculated and non-flocculated flotation tailing from the lead and zinc open pit mine 'Suplja stijena', Sula - Montenegro have been shown in this paper. Reason for this research was finding conditions in order to separate fraction that is suitable for embankment erection. Flotation tailings has been tested in the very state that it goes out from the flotation process and tailings which is flocculated by anionic flocculant. The object was to determine the impact of flocculation on properties of hydro-cycloning products and disposal process. In hydro-cycloning process greater underflow mass is being separated with non-flocculated tailing. Values of geomechanical parameters are significantly different, especially hydro-cyclone's underflow. All geomechanical parameters of hydro-cyclone's underflow are suitable for erecting embankment which shall be made from non-flocculated tailing. Underflow drainage of non-flocculated tailing is faster while overflow drainage is slower and problematic with both tailings.

Long-term ecological behaviour of abandoned uranium mill tailings. 1

International Nuclear Information System (INIS)

Kalin, M.

1983-03-01

Inactive uranium mill tailings were surveyed in the Province of Ontario to describe their surface characteristics, identify naturally invading biota, and determine essential chemical and physical parameters associated with the tailings. Inactive tailings sites can have wet areas, tailings completely covered with water, and dry areas. In the wet areas of most sites, wetland vegetation stands were found which were dominated by species of cattails (Typhaceae), along with some species of rushes (Juncaceae) and sedges (Cyperceae). Dry areas of the tailings exhibited a variety of surface features which are often a reflection of different amelioration efforts. Most of the indigenous species of vascular plants identified on dry areas of the tailings occurred only sporadically. Invading plants found on most sites were the tree species, trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera). Elemental concentration and some physical characteristics of the tailings collected from a depth of 0-20 cm were determined. Uptake of heavy metals and radionuclides were evaluated in trees found in the dry areas and in cattails (Typha latifolia) in the wetland areas. Water bodies on tailings and surface water leaving the tailings, before and after treatment, were characterized in this survey. Aquatic bryophytes have invaded some water bodies on the tailings, and acid tolerant algae were evident in most of the water associated with the tailings. Ecological processes occurring on inactive uranium mill tailings which were identified in this survey are essential in evaluating the long-term fate of these waste sites

Leachability of radioactive constituents from uranium mine tailings

International Nuclear Information System (INIS)

Constable, T.W.

1987-04-01

A series of long-term studies were conducted both to examine the leachability of major constituents (acidity, TDS) and radioisotopes from uranium mining/milling tailings and settling pond sludges, and to assess the effect of two treatment methods (solidification and vegetation) on leachate characteristics. Four bench-scale experiments were conducted to examine the leachability of: 1) old tailings and those containing a large portion of (Ba,Ra)SO 4 sludges; 2) untreated and solidified (Ba,Ra)SO 4 sludges located at the bottom of settling ponds; 3) new tailings that had been vegetated or solidified; and 4) new tailings subject to varying flow rates. A fifth study was conducted to examine the microbiology of Experiments 2 and 3. In addition, the lysimeter solids remaining in the old tailings at the end of Experiment 1 were characterized through chemical and radionuclide analyses and Scanning Electron Microscope-X-ray Emission and Mossbauer Spectroscopy techniques. This report provides an extensive database of temporal variations in leachate characteristics under both normal and accelerated water application rates. It also presents hypotheses of possible leaching mechanisms in the wastes that could explain the observed data, and conceptual model of tailings leaching processes which integrates the results of all the tailings experiments

How We Tend To Overestimate Powerlaw Tail Exponents

OpenAIRE

Nassim N. Taleb

2012-01-01

In the presence of a layer of metaprobabilities (from uncertainty concerning the parameters), the asymptotic tail exponent corresponds to the lowest possible tail exponent regardless of its probability. The problem explains "Black Swan" effects, i.e., why measurements tend to chronically underestimate tail contributions, rather than merely deliver imprecise but unbiased estimates.

Electrodialytic remediation of copper mine tailings

DEFF Research Database (Denmark)

Hansen, Henrik K.; Rojo, A.; Ottpsen, Lisbeth M.

2005-01-01

electrodialytic remediation experiments on copper mine tailings. The results show that electric current could remove copper from watery tailing if the potential gradient was higher than 2V/cm during 21 days. With addition of sulphuric acid, the process was enhanced because the pH decreased to around 4...

High energy neutron radiography

International Nuclear Information System (INIS)

Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G.; Zumbro, J.

1996-01-01

High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos

International experience in tailings pond remediation

Energy Technology Data Exchange (ETDEWEB)

MacG. Robertson, A. [Robertson GeoConsultants Ltd., Vancouver (Canada)

2001-07-01

Tailings pond remediation is required primarily on mine closure. While mining is an ancient industry, requirement for mine facility remediation is a comparatively new development. Requirement for remediation has come about partly as a result of mans awareness of the environmental impacts of mining and his desire to minimize this, partly, as a result of the ever-increasing scale and production rates of tailings generation and the resulting increased environmental impacts and safety risks. The paper starts with a review of the evolution of mans intolerance of environmental impacts from tailings production and the assignment of liability to remediate such impacts. Many of the tailings ponds currently undergoing remediation were designed and constructed using methods and technology that would be considered inappropriate for new impoundments being designed and developed today. The paper reviews the history of tailings impoundment design and construction practice and the resulting inherent deficiencies that must be remediated. Current practices and future trends in tailings pond remediation are reviewed. The evolution of regulatory requirements is not only in terms of technical and safety criteria, but also in terms of financial and political risk. Perhaps the most substantive driver of risk management is today the requirement for corporate governance at mining company board level and oversight of new project development in the underdeveloped countries by the large financial institutions responsible for funding projects. Embarrassment in the public eye and punishment in the stock markets for poor environmental and safety performance is driving the need for efficient and effective risk management of potential impacts and the remediation to avoid these. A basis for practical risk management is described. (orig.)

International experience in tailings pond remediation

International Nuclear Information System (INIS)

Robertson, A.MacG.

2001-01-01

Tailings pond remediation is required primarily on mine closure. While mining is an ancient industry, requirement for mine facility remediation is a comparatively new development. Requirement for remediation has come about partly as a result of mans awareness of the environmental impacts of mining and his desire to minimize this, partly, as a result of the ever-increasing scale and production rates of tailings generation and the resulting increased environmental impacts and safety risks. The paper starts with a review of the evolution of mans intolerance of environmental impacts from tailings production and the assignment of liability to remediate such impacts. Many of the tailings ponds currently undergoing remediation were designed and constructed using methods and technology that would be considered inappropriate for new impoundments being designed and developed today. The paper reviews the history of tailings impoundment design and construction practice and the resulting inherent deficiencies that must be remediated. Current practices and future trends in tailings pond remediation are reviewed. The evolution of regulatory requirements is not only in terms of technical and safety criteria, but also in terms of financial and political risk. Perhaps the most substantive driver of risk management is today the requirement for corporate governance at mining company board level and oversight of new project development in the underdeveloped countries by the large financial institutions responsible for funding projects. Embarrassment in the public eye and punishment in the stock markets for poor environmental and safety performance is driving the need for efficient and effective risk management of potential impacts and the remediation to avoid these. A basis for practical risk management is described. (orig.)

Baseline risk assessment of ground water contamination at the uranium mill tailings site Salt Lake City, Utah

International Nuclear Information System (INIS)

1994-09-01

This baseline risk assessment of groundwater contamination at the uranium mill tailings site near Salt Lake City, Utah, evaluates potential public health or environmental impacts resulting from ground water contamination at the former uranium ore processing site. The tailings and other contaminated material at this site were placed in a disposal cell located at Clive, Utah, in 1987 by the US Department of Energy's Uranium Mill Tailings Remedial Action (UMTRA) Project. The second phase of the UMTRA Project is to evaluate residual ground water contamination at the former uranium processing site, known as the Vitro processing site. This risk assessment is the first site-specific document under the Ground Water Project. It will help determine the appropriate remedial action for contaminated ground water at the site

Grasping convergent evolution in syngnathids: a unique tale of tails

Science.gov (United States)

Neutens, C; Adriaens, D; Christiaens, J; De Kegel, B; Dierick, M; Boistel, R; Van Hoorebeke, L

2014-01-01

Seahorses and pipehorses both possess a prehensile tail, a unique characteristic among teleost fishes, allowing them to grasp and hold onto substrates such as sea grasses. Although studies have focused on tail grasping, the pattern of evolutionary transformations that made this possible is poorly understood. Recent phylogenetic studies show that the prehensile tail evolved independently in different syngnathid lineages, including seahorses, Haliichthys taeniophorus and several types of so-called pipehorses. This study explores the pattern that characterizes this convergent evolution towards a prehensile tail, by comparing the caudal musculoskeletal organization, as well as passive bending capacities in pipefish (representing the ancestral state), pipehorse, seahorse and H. taeniophorus. To study the complex musculoskeletal morphology, histological sectioning, μCT-scanning and phase contrast synchrotron scanning were combined with virtual 3D-reconstructions. Results suggest that the independent evolution towards tail grasping in syngnathids reflects at least two quite different strategies in which the ancestral condition of a heavy plated and rigid system became modified into a highly flexible one. Intermediate skeletal morphologies (between the ancestral condition and seahorses) could be found in the pygmy pipehorses and H. taeniophorus, which are phylogenetically closely affiliated with seahorses. This study suggests that the characteristic parallel myoseptal organization as already described in seahorse (compared with a conical organization in pipefish and pipehorse) may not be a necessity for grasping, but represents an apomorphy for seahorses, as this pattern is not found in other syngnathid species possessing a prehensile tail. One could suggest that the functionality of grasping evolved before the specialized, parallel myoseptal organization seen in seahorses. However, as the grasping system in pipehorses is a totally different one, this cannot be

Geochemical Characterization of Copper Tailings after Legume Revegetation

Directory of Open Access Journals (Sweden)

Justine Perry T. Domingo

2014-12-01

Full Text Available Knowledge on the geochemistry of mine tailings is important in understanding the challenges in establishing vegetation cover on tailings dumps and mined out areas. In this study, the mineralogy and trace element composition of copper tailings were examined. Two legume species, Calopogonium mucunoides and Centrosema molle, were utilized to investigate the possible effects of these plants in the geochemical development of mine tailings into soil-like material. The initial mineralogical and chemical analysis of the tailings samples indicated poor conditions for plant growth—minimal levels of major nutrients and organic matter as well as elevated copper concentrations. Despite these conditions, the two legume species exhibited good growth rates. Both legumes have likewise signif icantly reduced heavy metal concentrations in the tailings, indicating the possibility of metal hyperaccumulation in the plant tissue. The mineral composition has been retained even after revegetation; nevertheless, breakdown of primary minerals and subsequent formation of clay minerals were detected. These results provide insights on the transformation of toxic materials into habitable substrates for sustained plant growth.

NGC 2782: A Merger Remnant with Young Stars in its Gaseous Tidal Tail

Science.gov (United States)

Torres-Flores, S.; de Oliveira, C. Mendes; de Mello, D. F.; Scarano, S. Jr.; Urrutia-Viscarra, R.

2012-01-01

We have searched for young star-forming regions around the merger remnant NGC 2782. By using GALEX FUV and NUV imaging and HI data we found seven UV sources, located at distances greater than 26 kpc from the center of NGG 2782, and coinciding with its western HI tidal tail. These regions were resolved in several smaller systems when Gemini/GMOS r-band images were used. We compared the observed colors to stellar population synthesis models and we found that these objects have ages of l to ll11yr and masses ranging from 10(exp 3.9) to l0(exp 4.6) Solar Mass. By using Gemini/GMOS spectroscopic data we confirm memberships and derive high metallicities for three of the young regions in the tail (12+log(O/H)=8.74+/-0.20, 8.81+/-0.20 and 8.78+/-0.20). These metallicities are similar to the value presented by the nuclear region of NGG 2782 and also similar to the value presented for an object located close to the main body of NGG 2782. The high metallicities measured for the star-forming regions in the gaseous tidal tail of NGG 2782 could be explained if they were formed out of highly enriched gas which was once expelled from the center of the merging galaxies when the system collided. An additional possibility is that the tail has been a nursery of a few generations of young stellar systems which ultimately polluted this medium with metals, further enriching the already pre-enriched gas ejected to the tail when the galaxies collided.

Net energy from nuclear power

International Nuclear Information System (INIS)

Perry, A.M.; Rotty, R.M.; Reister, D.B.

1977-01-01

Non-fission energy inputs to nuclear fuel cycles were calculated for four types of power reactors and for two grades of uranium ore. Inputs included all requirements for process operations, materials, and facility construction. Process stages are mining, milling, uranium conversion, enrichment, fuel fabrication, reprocessing, waste disposal, reactor construction and operation, and all transportation. Principal inputs were analyzed explicitly; small contributions and facility construction were obtained from input-output tables. For major facilities, the latter approach was based on disaggregated descriptions. Enrichment energy was that of U.S. diffusion plants, with uranium tails assay retained as a variable parameter. Supplemental electrical requirements, as a percentage of lifetime electrical output, are 5-6% for LWRs (0.3 - 0.2% tails assay) using ores with 0.2% uranium and without recycle. Recycle of uranium and plutonium reduces the electrical requirements 30%. Chattanooga Shales (0.006% U) require one-third more electricity. Thermal energy requirements are about 5% of electrical output with conventional ores; shales raise this to about 14%, with 0.2% enrichment tails and full recycle. About one-tenth of the electrical supplements and about a third of the thermal energy supplements are required prior to operation. A typical LWR will repay its energy loan within 15 months, allowing for low initial load factors. Enrichment requiring only 10% as much separative work as gaseous diffusion would reduce electrical requirements about 80%, but have little effect on thermal energy inputs. HTGRs require slightly less supplemental energy than LWRs. HWRs (with natural uranium) require about one-third as much supplemental electricity, but half again as much thermal energy, largely for heavy water production. The paper presents detailed data for several combinations of reactor type, ore grade and tails assay and compares them with conventional power plants. It also exhibits

An assessment of the long term interaction of uranium tailings with the natural environment

International Nuclear Information System (INIS)

Lush, D.; Fletcher, R.; Goode, J.; Jurgens, T.

1978-01-01

Current investigations of methods for the management of tailings at uranium mill sites raise pertinent questions as to accuracy of our identification of potential hazards and their causes. Of particular relevance are the physical-chemical geomechanisms which may lead to the dispersion of contaminants into the environment and eventually into the food chain. This paper looks at present practices of uranium mill tailings storage in the light of 'Perpetual Care' management concepts and requirements. It examines the potential geomechanisms of transport that would be acting on the tailing over the next millenia. Interesting parallels are drawn between these mechanisms and those geomechanisms which led to the formation of many of the original ore deposits. Central to the substance of this paper is a study currently being undertaken for the Atomic Energy Control Board of Canada. Selected elements to this study will be presented in the paper together with a discussion of relevant peripheral issues

Energy savings in sea bass swimming in a school: measurements of tail beat frequency and oxygen consumption at different swimming speeds

DEFF Research Database (Denmark)

Herskin, J; Steffensen, JF

1998-01-01

Tail beat frequency of sea bass, Dicentrarchus labrax (L.) (23.5 ± 0·5 cm, LT), swimming at the front of a school was significantly higher than when swimming at the rear, for all water velocities tested from 14·8 to 32 cm s-1. The logarithm of oxygen consumption rate, and the tail beat frequency...... of solitary swimming sea bass (28·8 ± 0·4 cm, LT), were each correlated linearly with swimming speed, and also with one another. The tail beat frequency of individual fish was 9-14% lower when at the rear of a school than when at the front, corresponding to a 9-23% reduction in oxygen consumption rate....

Thin-layer heap bioleaching of copper flotation tailings containing high levels of fine grains and microbial community succession analysis

Science.gov (United States)

Hao, Xiao-dong; Liang, Yi-li; Yin, Hua-qun; Liu, Hong-wei; Zeng, Wei-min; Liu, Xue-duan

2017-04-01

Thin-layer heap bioleaching of copper flotation tailings containing high levels of fine grains was carried out by mixed cultures on a small scale over a period of 210 d. Lump ores as a framework were loaded at the bottom of the ore heap. The overall copper leaching rates of tailings and lump ores were 57.10wt% and 65.52wt%, respectively. The dynamic shifts of microbial community structures about attached microorganisms were determined using the Illumina MiSeq sequencing platform based on 16S rRNA amplification strategy. The results indicated that chemolithotrophic genera Acidithiobacillus and Leptospirillum were always detected and dominated the microbial community in the initial and middle stages of the heap bioleaching process; both genera might be responsible for improving the copper extraction. However, Thermogymnomonas and Ferroplasma increased gradually in the final stage. Moreover, the effects of various physicochemical parameters and microbial community shifts on the leaching efficiency were further investigated and these associations provided some important clues for facilitating the effective application of bioleaching.

A ray-tracing study of electron cyclotron resonance heating in Tokamak plasmas with a superthermal electron tail

International Nuclear Information System (INIS)

Montes, A.; Dendy, R.O.

1987-09-01

We consider a Tokamak plasma in which the distribution of electron velocities in the direction parallel to the magnetic field has a monotonically decreasing superthermal tail. A fully three-dimensional ray-tracing code, which includes a realistic antenna pattern, toroidal effects, and refaction, is used to calculate the absorption of the extraordinary mode in the nonrelativistic limit away from perpendicular incidence. The ray-tracing approach extends results previously obtained in slab geometry (3-8) to a more realistic configuration; it is also essential in dealing with strong refraction in high-density plasmas. Our analytical model for the tail makes available a wide range of tail shapes and parameters. At low densities small tails (tail fraction [pt

Black-tailed Godwits in West African winter staging areas : habitat use and hunting-related mortality

NARCIS (Netherlands)

Kleijn, D.; Kamp, van der J.; Monteiro, H.; Ndiaye, I.; Wymenga, E.; Zwarts, L.

2010-01-01

The persistence of the Dutch Black-tailed Godwit population depends largely on high adult survival. Adult survival may be influenced by hunting pressure and land use change in the wintering area, the West African coastal zone. Here we examine hunting pressure on and habitat use of Black-tailed

Grouting of uranium mill tailings piles

International Nuclear Information System (INIS)

Boegly, W.J. Jr.; Tamura, T.; Williams, J.D.

1984-03-01

A program of remedial action was initiated for a number of inactive uranium mill tailings piles. These piles result from mining and processing of uranium ores to meet the nation's defense and nuclear power needs and represent a potential hazard to health and the environment. Possible remedial actions include the application of covers to reduce radon emissions and airborne transport of the tailings, liners to prevent groundwater contamination by leachates from the piles, physical or chemical stabilization of the tailings, or moving the piles to remote locations. Conventional installation of liners would require excavation of the piles to emplace the liner; however, utilization of grouting techniques, such as those used in civil engineering to stabilize soils, might be a potential method of producing a liner without excavation. Laboratory studies on groutability of uranium mill tailings were conducted using samples from three abandoned piles and employing a number of particulate and chemical grouts. These studies indicate that it is possible to alter the permeability of the tailings from ambient values of 10 -3 cm/s to values approaching 10 -7 cm/s using silicate grouts and to 10 -8 cm/s using acrylamide and acrylate grouts. An evaluation of grouting techniques, equipment required, and costs associated with grouting were also conducted and are presented. 10 references, 1 table

Long term population dose due to radon (Rn-222) released from uranium mill tailings

International Nuclear Information System (INIS)

Chambers, D.B.; Lower, L.M.; Stager, R.H.

2001-01-01

The results of a study undertaken by the European Commission on the external costs (environmental and social) of various energy production systems is likely to be influential in determining how the European Union will develop its energy supply systems. The estimated costs for nuclear power from the study will be based on the findings of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), with the costs being dominated by the estimated long term (10,000 y) population doses due to radon (Rn-222) released from mill tailings. UNSCEAR developed a central estimate of 150 person-Sv per GW y and a range of 1 to 1,000 person-Sv per GW y. However, the generic data available to and being used by UNSCEAR are dated and are not appropriate for the current and planned future conditions in the uranium production industry, with the result that the estimated external costs of nuclear power (specifically, the doses due to radon emitted from mill tailings) are overestimated. The Uranium Institute sponsored a study to estimate long term population doses based on the most recent 1993 UNSCEAR methodology, but using data that would be more appropriate to the current major uranium production facilities. Site-specific information obtained from the owners/operators and the Uranium Institute included: present and proposed tailings management plans; tailings volumes and areas; ore grades and reserves; measurements and estimates of radon emission rates; and population densities. Tailings at closed facilities that no longer contribute to uranium production were not evaluated since it was assumed that these radon sources need not be considered in evaluating the external costs of current and future nuclear power production. Based on the same approach as UNSCEAR, but using a more sophisticated air dispersion model, and more site-specific data relative to existing sites and proposed tailings management practices, radon emission rates and population densities (that