Technical safety requirements control level verification

A Technical Safety Requirement (TSR) control level verification process was developed for the Tank Waste Remediation System (TWRS) TSRs at the Hanford Site in Richland, WA, at the direction of the US. Department of Energy, Richland Operations Office (RL). The objective of the effort was to develop a process to ensure that the TWRS TSR controls are designated and managed at the appropriate levels as Safety Limits (SLs), Limiting Control Settings (LCSs), Limiting Conditions for Operation (LCOs), Administrative Controls (ACs), or Design Features. The TSR control level verification process was developed and implemented by a team of contractor personnel with the participation of Fluor Daniel Hanford, Inc. (FDH), the Project Hanford Management Contract (PHMC) integrating contractor, and RL representatives. The team was composed of individuals with the following experience base: nuclear safety analysis; licensing; nuclear industry and DOE-complex TSR preparation/review experience; tank farm operations; FDH policy and compliance; and RL-TWRS oversight. Each TSR control level designation was completed utilizing TSR control logic diagrams and TSR criteria checklists based on DOE Orders, Standards, Contractor TSR policy, and other guidance. The control logic diagrams and criteria checklists were reviewed and modified by team members during team meetings. The TSR control level verification process was used to systematically evaluate 12 LCOs, 22 AC programs, and approximately 100 program key elements identified in the TWRS TSR document. The verification of each TSR control required a team consensus. Based on the results of the process, refinements were identified and the TWRS TSRs were modified as appropriate. A final report documenting key assumptions and the control level designation for each TSR control was prepared and is maintained on file for future reference. The results of the process were used as a reference in the RL review of the final TWRS TSRs and control suite. RL concluded that the TSR control level verification process is clear and logically based upon DOE Order 5480.22, Technical Safety Requirements, and other TSR control selection guidelines. The process provides a documented, traceable basis for TSR level decisions and is a valid reference for preparation of new TSRs

Neutron-diffraction study of field-induced transitions in the heavy-fermion compound Ce2RhIn8

We present neutron diffraction measurements in high magnetic fields (0 to 14.5 T) and at low temperatures (2.5, 2.3, 0.77 and 0.068 K) on single crystals of the tetragonal heavy fermion antiferromagnet Ce2RhIn8. For B//[110] the field dependence of selected magnetic and nuclear reflections reveals that the material undergoes several transitions, the temperature dependence of which suggests a complex B-T phase diagram. We present the detailed evolution of the integrated intensities of selected reflections and discuss the associated field-induced transitions.Comment: 12 pages, 3 figures Proceeding Euro-conference "Properties of Condensed Matter probed by x-ray and neutron scattering"; to appear in Physica

Theory and experiment of the ESR of Co2+^{2+} in Zn2_2 % (OH)PO4_4 and Mg2_2(OH)AsO4_4

Experiments of Electron Spin Resonance (ESR) were performed on Co$$ substituting Zn$^{2+}$ or Mg$^{2+}$ in powder samples of Zn$_2$(OH)PO$_4$ and Mg$_2$(OH)AsO$_4$. The observed resonances are described with a theoretical model that considers the departures from the two perfect structures. It is shown that the resonance in the penta-coordinated complex is allowed, and the crystal fields that would describe the resonance of the Co$^{2+}$ in the two environments are calculated. The small intensity of the resonance in the penta-coordinated complex is explained assuming that this site is much less populated than the octahedral one; this assumption was verified by a molecular calculation of the energies of the two environments, with both Co and Zn as central ions in Zn$_2$(OH)PO$_4$.Comment: 43 pages, LaTex file, 6 figures, EPS. submitted to Journal of Physics Condens

Aerial Surveys for Cetaceans in the Former Akutan, Alaska, Whaling Grounds

Randomized aerial surveys were flown between 26 July and 26 August 1984 to search for cetaceans in two areas of southwestern Alaska: one on both Bering Sea and Pacific Ocean sides of the Aleutian Islands near the defunct Akutan shore-whaling station, which operated from 1912 through 1938, the other overlapping continental slope and shallow continental shelf waters between the Aleutians and the Pribilof Islands. ... Searches covered about 3940 nautical miles (nm), including some 2403 nm of random transects. Sightings were made of gray whales (10 sightings, 14 individuals), fin whales (3, 11), minke whales (1, 1), unidentified beaked whales (1, 6), Dall's porpoises (47, 131), killer whales (8, 26), and harbor porpoises (4, 7). A Fourier series model was used to estimate density of Dall's porpoises as 115 individuals (CV=0.263) per 1000 sq nm on the whaling grounds and 16.6 individuals (CV=0.0) per sq nm in the Bering Sea north of the whaling grounds. These estimates are comparable to those previously reported for the same general areas (97.2 animals per 1000 sq nm, SD=49.5). There were too few sightings of other cetaceans to permit calculation of meaningful density estimates. At least four species of great whales (blue, fin, humpback and sperm) were sufficiently abundant during the first four decades of this century to support significant whaling activities within about 100 sq nm of Akutan (more than 5300 whales were caught during 23 years of whaling, 1912-39). Although previous studies of the fisheries showed a downward trend in catch per unit of effort and an increase in distance traveled to take whales, whales were still being taken at relatively high rates (0.28-0.51 whales per gross catcher day) at the end of the fishery in 1939. Populations of fin, humpback, blue and sperm whales were probably significantly reduced by shore and pelagic whaling conducted widely in the North Pacific since 1939. ...Key words: aerial surveys, cetaceans, Bering Sea, North Pacific Ocean, historical whaling Des relevés aériens ont été effectués au hasard entre le 26 juillet et le 26 août 1984, afin de déterminer la présence de cétacés dans deux régions du Sud-Ouest de l'Alaska : l'une située des deux côtés des îles Aléoutiennes (du côté de la mer de Béring et du côté de l'océan Pacifique), près de ce qui fut jadis le port baleinier d'Akukan qui resta en opération de 1912 à 1939; l'autre couvrant à la fois les eaux du talus continental et celles, peu profondes, de la plate-forme continentale, entre les îles Aléoutiennes et les îles Pribilof. Les relevés furent effectuées à des altitudes comprises entre 150 et 245 m, d'un appareil d'observation Partenavia P68, muni d'un nez de plexiglas, permettant de voir dans l'axe de déplacement. Les recherches ont été effectuées sur environ 3940 milles nautiques (mn), y compris 2403 mn de recoupements au hasard. One a relevé la présence de baleines grises (10 relevés, 14 individus), de rorquals communs (3, 11), de petits rorquals (1, 1), de baleines à bec non identifiées (1, 6), de marsouins de Dall (47, 131), d'épaulards (8, 26) et de marsouins communs. On a utilisé un modèle en séries de Fourier pour déterminer approximativement la densité de marsouins de Dall à 115 individus (CV = 0.263) aux 1000 mn² dans les zones de pêche à la baleine, et à 16.6 individus (CV = 0.0) aux 1000 mn² dans la mer de Béring au nord des zones de pêche. Ces évaluations sont comparables à celles rapportées précédemment pour ces mêmes zones en général (97.2 animaux aux 1000 mn², DS = 49.5). Trop peu d'autres cétacés ont été aperçus pour justifier le calcul des densités approximatives. Durant les quarante premières années de ce siècle, il y avait au moins quatre espèces de grandes baleines (rorquals bleus, rorquals communs, rorquals à bosse et cachalots) en quantité suffisante pour alimenter une industrie baleinière dans un rayon d'environ 100 mn d'Akutan. (Plus de 5300 baleines furent pêchées durant les 23 années que dura la pêche à la baleine, de 1912 à 1939). Bien que des études précédentes sur la pêche aient montré une tendance à la baisse du nombre de prises par rapport au nombre d'unités d'effort et une augmentation de la distance à parcourir pour capturer les baleines, celles-ci étaient capturées à un taux relativement élevé (de 0.28 à 0.51 baleine par unité d'effort brute par jour) à la fin de la pêche en 1939. Les populations de rorquals communs, de rorquals à bosse, de rorquals bleus et de cachalots ont probablement été réduites de façon significative par le pêche côtière et la pêche pélagique, qui ont été pratiquées à grande échelle dans le Pacifique Nord depuis 1939. Le petit nombre de cétacés aperçus durant les présents relevés porte à croire que les populations dans les zones de pêche et dans leur vicinité, restent peu élevées en raison de ces activités. Mots clés : relevé aérien, cétacés, mer de Béring, Pacifique Nord, ancienne pêche à la balein

Sliding wear of a self-mated thermally sprayed chromium oxide coating in a simulated PWR water environment

Bearing surfaces in the primary circuit of pressurized water reactors (PWR) are prone to damage due to aggressive chemical and tribological conditions under which they operate, and a wide range of materials have been examined in this regard. One of the most promising candidates is chromium oxide in the form of a thermally spayed coating, and in this work, the behaviour of a commercially available Cr2O3 coating in self-mated sliding was considered. Tests consisted of a number of start-stop cycles of sliding between a crowned pin and a rotating disc in a water environment in an autoclave in an attempt to simulate the most aggressive phase of bearing run-up and run-down. Wear and damage mechanisms were examined at temperatures from ambient up to 250 C (a representative PWR environment). Samples were characterized before and after wear testing using mass measurements, profilometry, X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM) and X-ray photoelectron spectroscopy (XPS). Across the temperature range, wear was mild, with no evidence of coating delamination. A five-fold increase in wear was observed between 80 C and 250 C (with wear depths of generally less than 8 µm being observed on the disc samples even at the higher temperature), despite there being only very small changes in hardness of the coating over the same temperature range. Debris was observed on the wear tracks following testing, with the evidence together suggesting that this debris was a very fine-grained mixture of Cr2O3 and amorphous -CrOOH, a corrosion product of Cr2O3

Non-spherical sources of static gravitational fields: investigating the boundaries of the no-hair theorem

A new, globally regular model describing a static, non spherical gravitating object in General Relativity is presented. The model is composed by a vacuum Weyl--Levi-Civita special field - the so called gamma metric - generated by a regular static distribution of mass-energy. Standard requirements of physical reasonableness such as, energy, matching and regularity conditions are satisfied. The model is used as a toy in investigating various issues related to the directional behavior of naked singularities in static spacetimes and the blackhole (Schwarschild) limit.Comment: 10 pages, 2 figure

A source of a quasi--spherical space--time: The case for the M--Q solution

We present a physically reasonable source for an static, axially--symmetric solution to the Einstein equations. Arguments are provided, supporting our belief that the exterior space--time produced by such source, describing a quadrupole correction to the Schwarzschild metric, is particularly suitable (among known solutions of the Weyl family) for discussing the properties of quasi--spherical gravitational fields.Comment: 34 pages, 9 figures. To appear in GR

Ownership diversity and fragmentation: a barrier to urban centre resilience

Fragmentation of ownership has long been a recognised constraint to UK city centre development, a complexity that is growing in significance as centres try to manage the decline in physical retailing and transform obsolete retail units. Yet, our understanding of the structure of ownership and how that might be facilitating or inhibiting urban change remains weak. In this paper, the objective is to address this gap by examining the structure and diversity of land ownership in five retailing centres - Edinburgh, Glasgow, Hull, Liverpool, and Nottingham – between 2000–2017 using original databases created by linking administrative and commercial property data sets. Overall, the analysis finds property ownership to be spatially complex with ownership richness and diversity generally rising over the study period. The study also reveals that ownership structure has been shifting away from financial institutions towards overseas investors, private individuals and unlisted property companies, implying greater fragmentation of ownership. While the greater diversity in ownership should stimulate competition and innovation in property market practices, the shift in balance from equity-rich larger investors towards smaller and sometimes unknown investors makes urban centre management harder to manage. This suggests policymakers need to rethink the urban governance model to find a better way to galvanise the actions of this increasing disparate group of stakeholders if their visions of more resilient, mixed use city centres are to be realised

Specific pathway abundances in the neonatal calf faecal microbiome are associated with susceptibility to Cryptosporidium parvum infection: a metagenomic analysis.

Cryptosporidium parvum is the main cause of calf scour worldwide. With limited therapeutic options and research compared to other Apicomplexa, it is important to understand the parasites' biology and interactions with the host and microbiome in order to develop novel strategies against this infection. The age-dependent nature of symptomatic cryptosporidiosis suggests a link to the undeveloped immune response, the immature intestinal epithelium, and its associated microbiota. This led us to hypothesise that specific features of the early life microbiome could predict calf susceptibility to C. parvum infection. In this study, a single faecal swab sample was collected from each calf within the first week of life in a cohort of 346 animals. All 346 calves were subsequently monitored for clinical signs of cryptosporidiosis, and calves that developed diarrhoea were tested for Rotavirus, Coronavirus, E. coli F5 (K99) and C. parvum by lateral flow test (LFT). A retrospective case–control approach was taken whereby a subset of healthy calves (Control group; n = 33) and calves that went on to develop clinical signs of infectious diarrhoea and test positive for C. parvum infection via LFT (Cryptosporidium-positive group; n = 32) were selected from this cohort, five of which were excluded due to low DNA quality. A metagenomic analysis was conducted on the faecal microbiomes of the control group (n = 30) and the Cryptosporidium-positive group (n = 30) prior to infection, to determine features predictive of cryptosporidiosis. Taxonomic analysis showed no significant differences in alpha diversity, beta diversity, and taxa relative abundance between controls and Cryptosporidium-positive groups. Analysis of functional potential showed pathways related to isoprenoid precursor, haem and purine biosynthesis were significantly higher in abundance in calves that later tested positive for C. parvum (q ≤ 0.25). These pathways are either absent or streamlined in the C. parvum parasites. Though the de novo production of isoprenoid precursors, haem and purines are absent, C. parvum has been shown to encode enzymes that catalyse the downstream reactions of these pathway metabolites, indicating that C. parvum may scavenge those products from an external source. The host has previously been put forward as the source of essential metabolites, but our study suggests that C. parvum may also be able to harness specific metabolic pathways of the microbiota in order to survive and replicate. This finding is important as components of these microbial pathways could be exploited as potential therapeutic targets for the prevention or mitigation of cryptosporidiosis in bovine neonates