The high intensity diffractometer for residual stress analysis (HIDRA), a third generation residual stress mapping neutron diffractometer at the high flux isotope reactor

This paper describes the hardware and software upgrades, operation, and performance of the high intensity diffractometer for residual stress analysis (HIDRA) instrument, a residual stress mapping neutron diffractometer located at the High Flux Isotope Reactor at Oak Ridge National Laboratory in Oak Ridge Tennessee, USA. Following a major upgrade in 2018, the new instrument has a single ³He multiwire 2D 30 × 30 cm² position sensitive detector, yielding a field of view of 17° 2θ. The increase in the field of view (from 4° 2θ) from the previous model instrument has contributed to the tremendous improvement in the out of plane solid angle such that the 3D count rate could be obtained easily. Accordingly, the hardware, software, Data Acquisition System (DAS), and so on have also been updated. Finally, all these enhanced features of HIDRA have been ably demonstrated by conducting multi directional diffraction measurements in the quenched 750-T74 aluminum, and the evolved and improved strain/stress mappings are presented.

Influence of hydrological and geochemical processes on the transport of chelated metals and chromate in fractured shale bedrock

Field-scale processes governing the transport of chelated radionuclides in groundwater remain conceptually unclear for highly structured, heterogeneous environments. The objectives of this research were to provide an improved understanding and predictive capability of the hydrological and geochemical mechanisms that control the transport behavior of chelated radionuclides and metals in anoxic subsurface environments that are complicated by fracture flow and matrix diffusion. Our approach involved a long-term, steady-state natural gradient field experiment where nonreactive Br- and reactive 57Co(II)EDTA2- 109CdEDTA2-, and 51Cr(VI) were injected into a fracture zone of a contaminated fractured shale bedrock. The spatial and temporal distribution of the tracer and solutes was monitored for 500 days using an array of groundwater sampling wells instrumented within the fast-flowing fracture regime and a slower flowing matrix regime. The tracers were preferentially transported along strike-parallel fractures coupled with the slow diffusion of significant tracer mass into the bedrock matrix. The chelated radionuclides and metals were significantly retarded by the solid phase with the mechanisms of retardation largely due to redox reactions and sorption coupled with mineral-induced chelate-radionuclide dissociation. The formation of significant Fe(III)EDTA byproduct that accompanied the dissociation of the radionuclide-chelate complexes was believed to be the result of surface interactions with biotite which was the only Fe(III)-bearing mineral phase present in these Fe-reducing environments. These results counter current conceptual models that suggest chelated contaminants move conservatively through Fe-reducing environments since they are devoid of Fe-oxyhydroxides that are known to aggressively compete for chelates in oxic regimes. Modeling results further demonstrated that chelate-radionuclide dissociation reactions were most prevalent along fractures where accelerated weathering processes are expected to expose more primary minerals than the surrounding rock matrix. The findings of this study suggest that physical retardation mechanisms (i.e. diffusion) are dominant within the matrix regime, whereas geochemical retardation mechanisms are dominant within the fracture regime.

High-output cardiac failure related to hemodialysis arteriovenous fistula

Among the multiple etiologies for congestive heart failure in patients with end-stage renal disease, the contribution of hemodialysis fistulas to the myocardial work load is often overlooked. We recently cared for a patient with high-output cardiac failure from an arteriovenous fistula and review the features and pathophysiology of this condition.

Needs and anxiety levels in relatives of intensive care unit patients

The purpose of this study was to explore the perceived needs and anxiety levels of adult family members of intensive care unit (ICU) patients. The study was conducted over a 3-month period, on a convenience sample of 166 subjects selected from the total adult population of family members visiting an ICU patient in three Sudbury hospitals. Data were gathered using a self-report questionnaire, the Critical Care Family Needs Inventory (CCFNI) and Spielberger's State Trait Anxiety Inventory (STAI). Interviews were conducted in French or English according to the subject's preference. The major variables examined were: family needs; state and trait anxiety; on-site sources of worry; spiritual needs; level of knowledge of ICU from past experience or pre-surgery education; sociodemographic data. The Situational Anxiety Scale yielded a mean score of 45.24 and the Trait Anxiety Scale a mean score of 37.3. Inferential statistics demonstrated that family needs and situational anxiety were significantly related (P less than 0.0002). Furthermore, worries, trait anxiety, age and family needs explained 38% of the variation of situational anxiety. As well, spiritual needs and situational anxiety explained 33% of the variation of family needs.

Oceanographic Features of the Canadian Archipelago

Oceanographic data collected during the first cruise of H.M.C.S. Labrador to the Canadian Arctic in August and September 1954 permit comparisons of the vertical temperature and salinity structures in Baffin Bay, the Canadian Archipelago and the Arctic Ocean. From a comparison of the temperature–salinity characteristics of the waters in the Arctic Ocean (Beaufort Sea) with those in Baffin Bay, it is found that: (a) the surface waters of the Arctic Ocean are much less saline than those in Baffin Bay, but minimum temperatures are the same (−1.8 °C), (b) the waters of the upper 200 m. in Baffin Bay are denser than those found at corresponding depths in the Arctic Ocean, (c) below 200 m., Arctic waters are the denser, and below 500 m. they are denser than any waters found in Baffin Bay, and (d) waters found at 250 m. in the Beaufort Sea, at 500 m. in Smith Sound, and at 1250 m. in central Baffin Bay, have identical temperature and salinity characteristics (−0.3 °C., 34.4‰).In addition the data permitted limited investigations into the effect of drifting ice floes on the vertical temperature structure of the water, the origin of the "north water", long-term variations in the oceanographic conditions in Baffin Bay, and dynamic calculations of currents and volume transports of the waters through the channels leading into Baffin Bay.

On the Origin of Deep Baffin Bay Water

A comparison of the temperature–salinity relationships of waters found in the Arctic Ocean, Baffin Bay and Smith Sound shows that the deep Baffin Bay water originates in the Arctic Ocean rather than through an influx of a mixture of Labrador Sea deep water and Baffin Bay surface water, the salinity of which has been increased sufficiently by freezing to cause the water to sink, as suggested previously by other investigators.

The General Oceanography of the Strait of Belle Isle

Hydrographic data for late August, 1923, show for the Strait (a) progressive inward movement on the north side of Arctic or sub-Arctic water, (b) progressive outward movement on the south side of Gulf water and (c) a dominant outward flow with evidence of a previous dominant inward flow. Time differences suggest tidal causes for the marked temperature and salinity changes. Current measurements for a double tidal period indicate residual trends of nine and eight miles per day in opposite directions on the north and south sides of the Strait. Inside, the Esquiman Channel shows two contra-clockwise eddies north and south of the Mekattina Bank. In addition, hydrographic data show a strong northeasterly movement along the Newfoundland shore and a weaker southwesterly one along the opposite Quebec shore.Planktonic animals indicate the water movements, Mertensia, Acartia spiniremis, Themisto, Pseudalibrotus and Oikopleura vanhöffeni surviving to various degrees in the water from the Labrador Current that reaches the centre of the Gulf along the north shore of the Strait and Channel. Other forms characterize the warm shallow water along the Newfoundland shore inside the Strait and show its movement outward to the east coast of Newfoundland. The Greenland seal fishery of winter reflects the inward movement from the Labrador Current. Cod and herring fisheries invade this cool water of the north shore only locally in summer with access of warmer water from the south shore. Lobsters and cunners are very abundant in, but particularly confined to, the warm shallow water mentioned above.

Annual Variations of Temperature and Salinity in the Bay of Fundy

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The Slope Water off the Scotian Shelf

The slope water off the Scotian Shelf forms a well-defined band between the coastal waters and the Gulf Stream. Its boundaries fluctuate widely with no apparent systematics, sometimes transgressing upon the Shelf.A survey in November 1951 indicates the presence of alternate bands of cold and warm water in the slope water and suggests that these are the direct result of instability in the northern edge of the Gulf Stream. Observed velocities support such a hypothesis. Temperature-salinity relationships indicate that the slope water is formed of waters from the surface layers of the Gulf Stream, surface coastal waters, Labrador waters and deep Atlantic waters which have upwelled under the Gulf Stream.