Review of Design Approaches Applicable to Dewatering Uranium Mill Tailings Disposal Pits

This report is a review of design approaches in the literature that may be applicable to uranium mill tailings drainage. Tailings dewatering is required in the deep mined-out pits used for wet tailings disposal. Agricultural drainage theory is reviewed because it is seen as the most applicable technology. It is concluded that the standard drain-pipe envelope design criteria should be easily adapted. The differences in dewatering objectives and physical characteristics between agricultural and tailings drainage systems prevent direct technology transfer with respect to drain spacing calculations. Recommendations for further research are based on the drainage features unique to uranium mill tailings. It is recommended that transient solutions be applied to describe liquid movement through saturated and partially saturated tailings. Modeling should be used to evaluate the benefits of drainage design approaches after careful consideration of potential construction problems

Conformal Mapping on Rough Boundaries II: Applications to bi-harmonic problems

We use a conformal mapping method introduced in a companion paper to study the properties of bi-harmonic fields in the vicinity of rough boundaries. We focus our analysis on two different situations where such bi-harmonic problems are encountered: a Stokes flow near a rough wall and the stress distribution on the rough interface of a material in uni-axial tension. We perform a complete numerical solution of these two-dimensional problems for any univalued rough surfaces. We present results for sinusoidal and self-affine surface whose slope can locally reach 2.5. Beyond the numerical solution we present perturbative solutions of these problems. We show in particular that at first order in roughness amplitude, the surface stress of a material in uni-axial tension can be directly obtained from the Hilbert transform of the local slope. In case of self-affine surfaces, we show that the stress distribution presents, for large stresses, a power law tail whose exponent continuously depends on the roughness amplitude

Germanium Detector with Internal Amplification for Investigation of Rare Processes

Device of new type is suggested - germanium detector with internal amplification. Such detector having effective threshold about 10 eV opens up fresh opportunity for investigation of dark matter, measurement of neutrino magnetic moment, of neutrino coherent scattering at nuclei and for study of solar neutrino problem. Construction of germanium detector with internal amplification and perspectives of its use are described.Comment: 13 pages, latex, 3 figures, report at NANP-99, International Conference on Non-Accelerator Physics, Dubna, Russia, June 29- July 3, 1999. To be published in the Proceeding

Characterization of the first true coaxial 18-fold segmented n-type prototype detector for the GERDA project

The first true coaxial 18-fold segmented n-type HPGe prototype detector produced by Canberra-France for the GERDA neutrinoless double beta-decay project was tested both at Canberra-France and at the Max-Planck-Institut fuer Physik in Munich. The main characteristics of the detector are given and measurements concerning detector properties are described. A novel method to establish contacts between the crystal and a Kapton cable is presented.Comment: 21 pages, 16 Figures, to be submitted to NIM

New techniques for imaging and analyzing lung tissue.

The recent technological revolution in the field of imaging techniques has provided pathologists and toxicologists with an expanding repertoire of analytical techniques for studying the interaction between the lung and the various exogenous materials to which it is exposed. Analytical problems requiring elemental sensitivity or specificity beyond the range of that offered by conventional scanning electron microscopy and energy dispersive X-ray analysis are particularly appropriate for the application of these newer techniques. Electron energy loss spectrometry, Auger electron spectroscopy, secondary ion mass spectrometry, and laser microprobe mass analysis each offer unique advantages in this regard, but also possess their own limitations and disadvantages. Diffraction techniques provide crystalline structural information available through no other means. Bulk chemical techniques provide useful cross-checks on the data obtained by microanalytical approaches. It is the purpose of this review to summarize the methodology of these techniques, acknowledge situations in which they have been used in addressing problems in pulmonary toxicology, and comment on the relative advantages and disadvantages of each approach. It is necessary for an investigator to weigh each of these factors when deciding which technique is best suited for any given analytical problem; often it is useful to employ a combination of two or more of the techniques discussed. It is anticipated that there will be increasing utilization of these technologies for problems in pulmonary toxicology in the decades to come

Order reduction approaches for the algebraic Riccati equation and the LQR problem

We explore order reduction techniques for solving the algebraic Riccati equation (ARE), and investigating the numerical solution of the linear-quadratic regulator problem (LQR). A classical approach is to build a surrogate low dimensional model of the dynamical system, for instance by means of balanced truncation, and then solve the corresponding ARE. Alternatively, iterative methods can be used to directly solve the ARE and use its approximate solution to estimate quantities associated with the LQR. We propose a class of Petrov-Galerkin strategies that simultaneously reduce the dynamical system while approximately solving the ARE by projection. This methodology significantly generalizes a recently developed Galerkin method by using a pair of projection spaces, as it is often done in model order reduction of dynamical systems. Numerical experiments illustrate the advantages of the new class of methods over classical approaches when dealing with large matrices

Methiocarb-Treated Rice Seed Applied After Field Draining Fails to Repel Blackbirds from Sprouting Rice

Blackbirds, primarily Agelaius phoeniceus, cause extensive losses to sprouting rice in southwestern Louisiana. Methiocarb applied to seed prior to planting at rates above 1.0 g a.i./kg rice (0.1%) has provided excellent protection to sprouting rice in Louisiana under conditions of high bird pressure. To reduce treatment costs, some farmers have used over-flights of methiocarb-treated seed applied at low rates to part of the field after draining. This study showed this technique was not efficacious under conditions of high bird pressure. Four fields treated in this manner suffered 98% loss of sprouts compared to 100% loss in four untreated fields. Large flocks of blackbirds ( \u3e 3,000) fed in all treated and untreated fields during the first four days after draining. Blackbirds were evidently able to distinguish between treated (ungerminated) and untreated (germinated) seed. Large feeding flocks of blackbirds were composed almost entirely of females (x = 94%; n = 17); it is not known whether these birds were residents or migrants. We recommend that future studies investigate the efficacy of using mixtures of methiocarb-treated seed and untreated seed at planting time for reducing blackbird damage to sprouting rice. Blackbirds cause extensive losses to sprouting rice in southwestern Louisiana. Methiocarb applied to rice seed prior to planting at rates above 1.0 g a.i./kg seed provided excellent protection to sprouting rice in Louisiana under conditions of high bird pressure (Holler et al. 1985). Use of methiocarb by growers under emergency (Section 18) exemption from the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) has been low, largely due to the high cost of treating all rice seed used in planting (Holler et al. 1982, 1985). In 1985 we determined the feasibility of protecting newly planted rice fields from blackbird damage by aerially applying treated seed on the fields upon completion of drainage after planting. This method has been used by farmers in Louisiana and subjective evaluation of its effectivness has been inconclusive. If efficacious, this method would provide the grower with a measure that could be used after planting when bird pressure is known to be high. It would also reduce residues in drainage water and it would result in substantial reduction in the cost of protection. Personnel of the Crowley, Louisiana Field Station, U.S.D.A. (formerly U.S. Fish and Wildlife Service), provided logistical support. A. Wilson, Rice Research Station, Louisiana State University, Crowley, Louisiana collected sprout count data from one field. Mesurol®4/75% Seed Treater for this test was provided by the Mobay Chemical Corporation, Kansas City, Missouri. The study was conducted by the U.S. Fish and Wildlife Service, Department of the Interior. The Animal Damage Control Program, including the Denver Wildlife Research Center, was transferred to USDA-APHIS (Animal and Plant Health Inspection Service) on 3 March 1986

Microstructural characterization and simulation of damage for geared sheet components

The evolution of damage in geared components manufactured from steel sheets was investigated, to analyse the influence of damage caused by the sheet-bulk-metal forming. Due to the inhomogeneous and multi-axial deformation in the investigated parts, different aspects such as the location-dependent shape and size of voids are analysed by means of various microscopic methods. In particular, a method to characterize the state of damage evolution, i. e. void nucleation, growth and coalescence using scanning electron microscopy (SEM) is applied. The investigations reveal a strong dependence of the void area fraction, shape of voids and thus damage evolution on the loading mode. The microstructural analysis is complemented with FEM simulations using material models which consider the characteristics of the void evolution. © Published under licence by IOP Publishing Ltd

Photonic Clusters

We show through rigorous calculations that dielectric microspheres can be organized by an incident electromagnetic plane wave into stable cluster configurations, which we call photonic molecules. The long-range optical binding force arises from multiple scattering between the spheres. A photonic molecule can exhibit a multiplicity of distinct geometries, including quasicrystal-like configurations, with exotic dynamics. Linear stability analysis and dynamical simulations show that the equilibrium configurations can correspond with either stable or a type of quasi-stable states exhibiting periodic particle motion in the presence of frictional dissipation.Comment: 4 pages, 3 figure