588 research outputs found
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Calculation note for an underground leak which remains underground
This calculation note supports the subsurface leak accident scenario which remains subsurface. It is assumed that a single walled pipe carrying waste from tank 106-C ruptures, releasing the liquid waste into the soil. In this scenario, the waste does not form a surface pool, but remains subsurface. However, above the pipe is a berm, 0.762 m (2.5 ft) high and 2.44 m (8 ft) wide, and the liquid released from the leak rises into the berm. The slurry line, which transports a source term of higher activity than the sluice line, leaks into the soil at a rate of 5% of the maximum flow rate of 28.4 L/s (450 gpm) for twelve hours. The dose recipient was placed a perpendicular distance of 100 m from the pipe. Two source terms were considered, mitigated and unmitigated release as described in section 3.4.1 of UANF-SD-WM-BIO-001, Addendum 1. The unmitigated consisted of two parts of AWF liquid and one part AWF solid. The mitigated release consisted of two parts SST liquid, eighteen parts AWF liquid, nine parts SST solid, and one part AWF solid. The isotopic breakdown of the release in these cases is presented. Two geometries were considered in preliminary investigations, disk source, and rectangular source. Since the rectangular source results from the assumption that the contamination is wicked up into the berm, only six inches of shielding from uncontaminated earth is present, while the disk source, which remains six inches below the level of the surface of the land is often shielded by a thick shield due to the slant path to the dose point. For this reason, only the rectangular source was considered in the final analysis. The source model was a rectangle 2.134 m (7 ft) thick, 0.6096 m (2 ft) high, and 130.899 m (131 ft) long. The top and sides of this rectangular source was covered with earth of density 1.6 g/cm{sup 3} to a thickness of 15.24 cm (6 in). This soil is modeled as 40% void space. The source consisted of earth of the same density with the void spaces filled with the liquid waste which added 0.56 g/cm{sup 3} to the density. The dose point was 100 m (328 ft) away from the berm in a perpendicular direction off the center. The computer code MICROSKYSHINEO was used to calculate the skyshine from the source. This code calculates exposure rate at the receptor point. The photon spectrum from 2 MeV to 0.15 MeV, obtained from ISOSHLD, was used as input, although this did not differ substantially from the results obtained from using Co, 137mBa, and 154Eu. However, this methodology allowed the bremsstrahlung contribution to be included in the skyshine calculation as well as in the direct radiation calculation
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Shielding requirements for K Basin waste transfer line
K-East Basin sludge, mixed with water, is to be transported to the tank farms using a high integrity container mounted on a trailer. Load considerations preclude driving the truck directly to the tank opening. Thus, it is envisioned that a transfer line will run from a tanker unloading point to a point where the waste can be injected into a waste tank. It is presently envisioned that the waste will be pumped from the truck to the tank in a three inch pipe which is encased inside a six inch pipe. The transfer line will be shielded by either berming earth with a density of approximately 2.00 g/cm{sup 3} (125 lb/ft{sup 3}) around the line, or constructing a concrete raceway
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Calculational note in support of inventory assessment of three tank trailers using radiological attentuation calculations
An estimate of tanker inventory using radiological attenuation calculations
Analytic models of plausible gravitational lens potentials
Gravitational lenses on galaxy scales are plausibly modelled as having
ellipsoidal symmetry and a universal dark matter density profile, with a Sersic
profile to describe the distribution of baryonic matter. Predicting all lensing
effects requires knowledge of the total lens potential: in this work we give
analytic forms for that of the above hybrid model. Emphasising that complex
lens potentials can be constructed from simpler components in linear
combination, we provide a recipe for attaining elliptical symmetry in either
projected mass or lens potential. We also provide analytic formulae for the
lens potentials of Sersic profiles for integer and half-integer index. We then
present formulae describing the gravitational lensing effects due to
smoothly-truncated universal density profiles in cold dark matter model. For
our isolated haloes the density profile falls off as radius to the minus fifth
or seventh power beyond the tidal radius, functional forms that allow all
orders of lens potential derivatives to be calculated analytically, while
ensuring a non-divergent total mass. We show how the observables predicted by
this profile differ from that of the original infinite-mass NFW profile.
Expressions for the gravitational flexion are highlighted. We show how
decreasing the tidal radius allows stripped haloes to be modelled, providing a
framework for a fuller investigation of dark matter substructure in galaxies
and clusters. Finally we remark on the need for finite mass halo profiles when
doing cosmological ray-tracing simulations, and the need for readily-calculable
higher order derivatives of the lens potential when studying catastrophes in
strong lenses.Comment: 24 pages, 10 figures, matches published versio
A systematic review of techniques and effects of self-help interventions for tinnitus: application of taxonomies from health psychology
Objective: Self-help interventions are followed by people independently with minimal or no therapist contact. This review aims to assess the effectiveness of self-help interventions for adults with chronic tinnitus and systematically identify the self-help techniques used. Design: Systematic review and application of health psychology taxonomies. Electronic database searches were conducted, supplemented by citation searching and hand-searching of key journals. Prospective controlled trials, which used measures of tinnitus distress, functional management, anxiety, depression, and quality of life, were included. Michie et al’s behaviour change techniques (BCTs) taxonomy and Taylor et al’s PRISMS taxonomy of self-management components were applied to describe interventions. Study sample: Five studies were included, providing low-to-moderate levels of evidence. Results: Randomized controlled trial studies were too few and heterogeneous for meta-analysis to be performed. Studies comparing self-help interventions to therapist-guided interventions and assessing non tinnitus-specific psychosocial outcomes and functional management were lacking. Fifteen BCTs and eight self-management components were identified across interventions. Conclusions: A lack of high-quality and homogeneous studies meant that confident conclusions could not be drawn regarding the efficacy of self-help interventions for tinnitus. Better reporting and categorization of intervention techniques is needed for replication in research and practice and to facilitate understanding of intervention mechanisms
Mid‐Holocene site formation, diagenesis and human activity at the foothills of Serra da Estrela (Portugal)
UIDB/00749/2020 UIDP/00749/2020The Neolithic occupation of Penedo dos Mouros in the foothills of Serra da Estrela, Portugalʼs highest mountain, dates to the 5th to 4th millennia cal B.C. The siteʼs faunal assemblage is extremely rare in the regional prehistoric archaeological record, due to the acidity of the granitic geology. This underlines Penedo dos Mouros importance as a reference site for understanding early pastoralism in the region. Due to the insufficient survival of bone collagen for radiocarbon dating and the homogeneity of the stratigraphy, where most visible contacts are due to postdepositional processes, we chose micromorphology to address the reasons behind the bone preservation and to assess the stratigraphic integrity of the prehistoric deposit. Reworking of eroding saprolitic soils was a major factor in the sediment accumulation, with remains of short human occupation events. Possible evidence for clearance fires linked to the first occurrences of pastoralism practised in the region, creating open spaces for grazing, was identified. Post‐depositional carbonate cementation derived from ashes, identifiable at the microscopic scale, enabled bone preservation. Carbonate and spodic‐like features document water saturation once the sedimentation ceased. This sedimentary dynamic has broader geomorphological implications, such as an inferred post‐Neolithic incision of the stream valley adjacent to the site.publishersversionpublishe
Measurement of the partial widths of the Z into up- and down-type quarks
Using the entire OPAL LEP1 on-peak Z hadronic decay sample, Z -> qbarq gamma
decays were selected by tagging hadronic final states with isolated photon
candidates in the electromagnetic calorimeter. Combining the measured rates of
Z -> qbarq gamma decays with the total rate of hadronic Z decays permits the
simultaneous determination of the widths of the Z into up- and down-type
quarks. The values obtained, with total errors, were Gamma u = 300 ^{+19}_{-18}
MeV and Gamma d = 381 ^{+12}_{-12} MeV. The results are in good agreement with
the Standard Model expectation.Comment: 22 pages, 5 figures, Submitted to Phys. Letts.
Search for R-Parity Violating Decays of Scalar Fermions at LEP
A search for pair-produced scalar fermions under the assumption that R-parity
is not conserved has been performed using data collected with the OPAL detector
at LEP. The data samples analysed correspond to an integrated luminosity of
about 610 pb-1 collected at centre-of-mass energies of sqrt(s) 189-209 GeV. An
important consequence of R-parity violation is that the lightest supersymmetric
particle is expected to be unstable. Searches of R-parity violating decays of
charged sleptons, sneutrinos and squarks have been performed under the
assumptions that the lightest supersymmetric particle decays promptly and that
only one of the R-parity violating couplings is dominant for each of the decay
modes considered. Such processes would yield final states consisting of
leptons, jets, or both with or without missing energy. No significant
single-like excess of events has been observed with respect to the Standard
Model expectations. Limits on the production cross- section of scalar fermions
in R-parity violating scenarios are obtained. Constraints on the supersymmetric
particle masses are also presented in an R-parity violating framework analogous
to the Constrained Minimal Supersymmetric Standard Model.Comment: 51 pages, 24 figures, Submitted to Eur. Phys. J.
Measurement of the Strong Coupling alpha s from Four-Jet Observables in e+e- Annihilation
Data from e+e- annihilation into hadrons at centre-of-mass energies between
91 GeV and 209 GeV collected with the OPAL detector at LEP, are used to study
the four-jet rate as a function of the Durham algorithm resolution parameter
ycut. The four-jet rate is compared to next-to-leading order calculations that
include the resummation of large logarithms. The strong coupling measured from
the four-jet rate is alphas(Mz0)=
0.1182+-0.0003(stat.)+-0.0015(exp.)+-0.0011(had.)+-0.0012(scale)+-0.0013(mass)
in agreement with the world average. Next-to-leading order fits to the
D-parameter and thrust minor event-shape observables are also performed for the
first time. We find consistent results, but with significantly larger
theoretical uncertainties.Comment: 25 pages, 15 figures, Submitted to Euro. Phys. J.
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