1,063 research outputs found
The Living Together Arrangement: Social Work and the Lost Client
A recent research study suggests that persons living together outside of marriage do not view social work services as a potential source of help for problems brought into the living together arrangement, those common to all intimate long-range dyadic relationships or those directly related to choice of lifestyle. A multi-faceted approach is suggested which would aim at reaching this potential client group in a climate which will neither stigmatize or judge the alternate lifestyle or the persons who practice it
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SAVANNAH RIVER SITE R REACTOR DISASSEMBLY BASIN IN SITU DECOMMISSIONING
The US DOE concept for facility in-situ decommissioning (ISD) is to physically stabilize and isolate in tact, structurally sound facilities that are no longer needed for their original purpose of, i.e., generating (reactor facilities), processing(isotope separation facilities) or storing radioactive materials. The 105-R Disassembly Basin is the first SRS reactor facility to undergo the in-situ decommissioning (ISD) process. This ISD process complies with the105-R Disassembly Basin project strategy as outlined in the Engineering Evaluation/Cost Analysis for the Grouting of the R-Reactor Disassembly Basin at the Savannah River Site and includes: (1) Managing residual water by solidification in-place or evaporation at another facility; (2) Filling the below grade portion of the basin with cementitious materials to physically stabilize the basin and prevent collapse of the final cap - Sludge and debris in the bottom few feet of the basin will be encapsulated between the basin floor and overlying fill material to isolate if from the environment; (3) Demolishing the above grade portion of the structure and relocating the resulting debris to another location or disposing of the debris in-place; and (4) Capping the basin area with a concrete slab which is part of an engineered cap to prevent inadvertent intrusion. The estimated total grout volume to fill the 105-R Reactor Disassembly Basin is 24,424 cubic meters or 31,945 cubic yards. Portland cement-based structural fill materials were design and tested for the reactor ISD project and a placement strategy for stabilizing the basin was developed. Based on structural engineering analyses and work flow considerations, the recommended maximum lift height is 5 feet with 24 hours between lifts. Pertinent data and information related to the SRS 105-R-Reactor Disassembly Basin in-situ decommissioning include: regulatory documentation, residual water management, area preparation activities, technology needs, fill material designs and testing, and fill placement strategy. This information is applicable to decommissioning both the 105-P and 105-R facilities. The ISD process for the entire 105-P and 105-R reactor facilities will require approximately 250,000 cubic yards (191,140 cubic meters) of grout and 2,400 cubic yards (1,840 cubic meters) of structural concrete which will be placed over a twelve month period to meet the accelerated schedule ISD schedule. The status and lessons learned in the SRS Reactor Facility ISD process will be described
Excitation energy transfer in light-harvesting system: Effect of initial state
The light-harvesting is a problem of long interest. It becomes active again
in recent years stimulated by suggestions of quantum effects in energy
transport. Recent experiments found evidence that BChla 1 and BChla 6 are the
first to be excited in the Fenna-Matthews-Olson(FMO) protein, theoretical
studies, however, are mostly restricted to consider the exciton in BChla 1
initially. In this paper, we study the energy transport in the FMO complex by
taking different initial states into account. Optimizations are performed for
the decoherence rates as to maximal transport efficiency. Dependence of the
energy transfer efficiency on the initial states is given and discussed.
Effects of fluctuations in the site energies and couplings are also examined.Comment: 6 pages, 6 figures, J Phys B accepte
Constant amplitude and post-overload fatigue crack growth behavior in PM aluminum alloy AA 8009
A recently developed, rapidly solidified, powder metallurgy, dispersion strengthened aluminum alloy, AA 8009, was fatigue tested at room temperature in lab air. Constant amplitude/constant delta kappa and single spike overload conditions were examined. High fatigue crack growth rates and low crack closure levels compared to typical ingot metallurgy aluminum alloys were observed. It was proposed that minimal crack roughness, crack path deflection, and limited slip reversibility, resulting from ultra-fine microstructure, were responsible for the relatively poor da/dN-delta kappa performance of AA 8009 as compared to that of typical IM aluminum alloys
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Thermoelectric Nuclear Fuel Element Quarterly Progress Report for April- June 1960
A hot-pressing system was designed and is adaptable for bomb melting experiments up to 2000 deg C. Two devices were constructed for measuring. One was designed to measure Seebeck coefficients, resistivities, and bond resistances of swaged and machined thermoelectric wafers and the other was designed to measure thermoelectric parameters of cylindrical thermoelectric pellets up to 1000 deg C. Design studies on a fission-fired thermoelectric generator were completed. Seebeck coefficient and resistivity were determined for Li/sub .06/Ni/ sub .94/ and p type PbTe as a function of thermal fiux at 400 deg C (average). Designs of prototype thermonuclear fuel elements are presented which include single-leg, double-leg, multi-junction notched-bar, and multi-junction pelletized designs. The effects of heattreatment on the thermoelectric properties of n and p type PbTe were determined at 68 deg F. The compatibility of PbTe and GeTe with cladding materials was investigated at 510, 600, and 650 deg C. The results of life testing a swaged single-leg GeTe element are discussed. The nuclear characteristics of a 500-kw thermoelectric core that employs a rod-type fuel element were calculated. Designs of a thermoelectric reactor system that utilizes thermal circulation are presented. (For preceding period see WCAP- 1545.) (C.J.G.
Non-Markovian stochastic description of quantum transport in photosynthetic systems
We analyze several aspects of the transport dynamics in the LH1-RC core of
purple bacteria, which consists basically in a ring of antenna molecules that
transport the energy into a target molecule, the reaction center, placed in the
center of the ring. We show that the periodicity of the system plays an
important role to explain the relevance of the initial state in the transport
efficiency. This picture is modified, and the transport enhanced for any
initial state, when considering that molecules have different energies, and
when including their interaction with the environment. We study this last
situation by using stochastic Schr{\"o}dinger equations, both for Markovian and
non-Markovian type of interactions.Comment: 21 pages, 5 figure
Characterizing sub-glacial hydrology using radar simulations
The structure and distribution of sub-glacial water directly influences Antarctic ice mass loss by reducing or enhancing basal shear stress and accelerating grounding line retreat. A common technique for detecting sub-glacial water involves analyzing the spatial variation in reflectivity from an airborne radar echo sounding (RES) survey. Basic RES analysis exploits the high dielectric contrast between water and most other substrate materials, where a reflectivity increase ≥ 15 dB is frequently correlated with the presence of sub-glacial water. There are surprisingly few additional tools to further characterize the size, shape, or extent of hydrological systems beneath large ice masses.
We adapted an existing radar backscattering simulator to model RES reflections from sub-glacial water structures using the University of Texas Institute for Geophysics (UTIG) Multifrequency Airborne Radar Sounder with Full-phase Assessment (MARFA) instrument. Our series of hypothetical simulation cases modeled water structures from 5 to 50 m wide, surrounded by bed materials of varying roughness. We compared the relative reflectivity from rounded Röthlisberger channels and specular flat canals, showing both types of channels exhibit a positive correlation between size and reflectivity. Large (> 20 m), flat canals can increase reflectivity by more than 20 dB, while equivalent Röthlisberger channels show only modest reflectivity gains of 8–13 dB. Changes in substrate roughness may also alter observed reflectivity by 3–6 dB. All of these results indicate that a sophisticated approach to RES interpretation can be useful in constraining the size and shape of sub-glacial water features. However, a highly nuanced treatment of the geometric context is necessary.
Finally, we compared simulated outputs to actual reflectivity from a single RES flight line collected over Thwaites Glacier in 2022. The flight line crosses a previously proposed Röthlisberger channel route, with an obvious bright bed reflection in the radargram. Through multiple simulations comparing various water system geometries, such as canals and sub-glacial lakes, we demonstrated the important role that topography and water geometry can play in observed RES reflectivity. From the scenarios that we tested, we concluded the bright reflector from our RES flight line cannot be a Röthlisberger channel but could be consistent with a series of flat canals or a sub-glacial lake. However, we note our simulations were not exhaustive of all possible sub-glacial water configurations.
The approach outlined here has broad applicability for studying the basal environment of large glaciers. We expect to apply this technique when constraining the geometry and extent of many sub-glacial hydrologic structures in the future. Further research may also include comprehensive investigations of the impact of sub-glacial roughness, substrate heterogeneity, and computational efficiencies enabling more complex and complete simulations.</p
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USE OF CEMENTITIOUS MATERIALS FOR SRS REACTOR FACILITY IN-SITU DECOMMISSIONING - 11620
The United States Department of Energy (US DOE) concept for facility in-situ decommissioning (ISD) is to physically stabilize and isolate in tact, structurally sound facilities that are no longer needed for their original purpose of, i.e., producing (reactor facilities), processing (isotope separation facilities) or storing radioactive materials. The Savannah River Site 105-P and 105-R Reactor Facility ISD requires about 250,000 cubic yards of grout to fill the below grade structure. The fills are designed to prevent subsidence, reduce water infiltration, and isolate contaminated materials. This work is being performed as a Comprehensive Environmental Response, Compensations and Liability Act (CERCLA) action and is part of the overall soil and groundwater completion projects for P- and R-Areas. Cementitious materials were designed for the following applications: (1) Below grade massive voids/rooms: Portland cement-based structural flowable fills for - Bulk filling, Restricted placement and Underwater placement. (2) Special below grade applications for reduced load bearing capacity needs: Cellular portland cement lightweight fill (3) Reactor vessel fills that are compatible with reactive metal (aluminum metal) components in the reactor vessels: Calcium sulfoaluminate flowable fill, and Magnesium potassium phosphate flowable fill. (4) Caps to prevent water infiltration and intrusion into areas with the highest levels of radionuclides: Portland cement based shrinkage compensating concrete. A system engineering approach was used to identify functions and requirements of the fill and capping materials. Laboratory testing was performed to identify candidate formulations and develop final design mixes. Scale-up testing was performed to verify material production and placement as well as fresh and cured properties. The 105-P and 105-R ISD projects are currently in progress and are expected to be complete in 2012. The focus of this paper is to describe the (1) grout mixes for filling the reactor vessels, and (2) a specialty grout mix to fill a selected portion of the P-Reactor Disassembly Basin. Details of the grout mixes designed for ISD of he SRS Reactor Disassembly Basins and below grade portions of the 105-Buildings was described elsewhere. Material property test results, placement strategies, full-scale production and delivery systems will also be described
Recent magnetic views of the Antarctic lithosphere
Magnetic anomaly investigations are a key tool to help unveil subglacial geology, crustal architecture and the tectonic and geodynamic evolution of the Antarctic continent. Here, we present the second generation Antarctic magnetic anomaly compilation ADMAP 2.0 (Golynsky et al., 2018), that now includes a staggering 3.5 million line-km of aeromagnetic and marine magnetic data, more than double the amount of data available in the first generation effort. All the magnetic data were corrected for the International Geomagnetic Reference Field, diurnal effects, high-frequency errors and leveled, gridded,and stitched together.
The new magnetic anomaly dataset provides tantalising new views into the structure and evolution of the Antarctic Peninsula and the West Antarctic Rift System within West Antarctica, and Dronning Maud Land, the Gamburtsev Subglacial Mountains, the Prince Charles Mountains, Princess Elizabeth Land, and Wilkes Land in East Antarctica, as well as key insights into oceanic gateways.
Our magnetic anomaly compilation is helping unify disparate regional geologic and geophysical studies by providing larger-scale perspectives into the major tectonic and magmatic processes that affected Antarctica from Precambrian to Cenozoic times, including e.g. the processes of subduction and magmatic arc development, orogenesis, accretion, cratonisation and continental rifting, as well as continental margin and oceanic basin evolution. The international Antarctic geomagnetic community remains very active in the wake of ADMAP 2.0, and we will showcase some of their key ongoing study areas, such as the South Pole and Recovery frontiers, the Ross Ice Shelf, Dronning Maud Land and Princess Elizabeth Land
Clinical outcomes after detection of elevated cardiac enzymes in patients undergoing percutaneous intervention
AbstractObjectives. We examined the relations of elevated creatine kinase (CK) and its myocardial band isoenzyme (CK-MB) to clinical outcomes after percutaneous coronary intervention (PCI) in patients enrolled in Integrilin (eptifibatide) to Minimize Platelet Aggregation and Coronary Thrombosis-II (trial) (IMPACT-II), a trial of the platelet glycoprotein IIb/IIIa inhibitor eptifibatide.Background. Elevation of cardiac enzymes often occurs after PCI, but its clinical implications are uncertain.Methods. Patients undergoing elective, scheduled PCI for any indication were analyzed. Parallel analyses investigated CK (n = 3,535) and CK-MB (n = 2,341) levels after PCI (within 4 to 20 h). Clinical outcomes at 30 days and 6 months were stratified by postprocedure CK and CK-MB (multiple of the site’s upper normal limit).Results. Overall, 1,779 patients (76%) had no CK-MB elevation; CK-MB levels were elevated to 1 to 3 times the upper normal limit in 323 patients (13.8%), to 3 to 5 times normal in 84 (3.6%), to 5 to 10 times normal in 86 (3.7%), and to >10 times normal in 69 patients (2.9%). Elevated CK-MB was associated with an increased risk of death, reinfarction, or emergency revascularization at 30 days, and of death, reinfarction, or surgical revascularization at 6 months. Elevated total CK to above three times normal was less frequent, but its prognostic significance paralleled that seen for CK-MB. The degree of risk correlated with the rise in CK or CK-MB, even for patients with successful procedures not complicated by abrupt closure.Conclusions. Elevations in cardiac enzymes, including small increases (between one and three times normal) often not considered an infarction, are associated with an increased risk for short-term adverse clinical outcomes after successful or unsuccessful PCI
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