The objective of this two-part paper is to provide clarity to physical concepts used in the field of transformer modeling, to dispel common misconceptions regarding numerical instabilities, and to ...present unified modeling techniques for low-frequency transients. This paper focuses on proper modeling of nonlinearities (magnetizing branches) since these components are critical to determine the low-frequency behavior. A good low-frequency model should properly represent: normal operation, inrush currents, open and short circuit, out-of-phase synchronization transient of step-up transformers, geomagnetic-induced currents, ferroresonance, and harmonics. This paper discusses the derivation of electrical dual models from the equivalent (magnetic) reluctance networks and the direct application of the principle of duality. It is shown that different dual models need to be derived for different transformer geometries and the advantages and disadvantages of each method are discussed. This paper also compares double-sided versus single-sided dual models, and shows that the double-sided model is a more general approach. The mathematical equivalency of several leakage models (negative inductance, mutual coupling, and BCTRAN) is demonstrated for three-winding transformers. It is also shown that contrary to common belief, a negative inductance is not the source of numerical oscillations, but they occur due to the use of noncorrect topological models for representing the core.
Hot Isostatic Pressing (HIPing) is a batch process thermal treatment technology where wastes are heated and compressed within a sealed stainless steel canister; typically resulting in durable, high ...density ceramics or glasses with minimal loss of volatile elements, and accountability of active inventories. The University of Sheffield has a small-scale research HIP with capability to process simulant wasteforms containing radioactive materials, to help underpin larger-scale industrial applications of this technology. It was under this remit that a series of trials were undertaken, to produce small simulant radioactive wasteforms incorporating problematic UK waste streams such as Magnox sludges and clinoptilolite ion-exchange material. Each trial was successfully batched, sealed, and HIPed at 1250 °C, resulting in solidified products entirely contained within the steel HIP canisters. The ability to safely produce active wasteforms within the same facility validates the active furnace isolation chamber (AFIC) system. Overall the success of these trials demonstrate the ability of smaller research HIP facilities to build up the scientific and technical case for further implementation of HIP technology as a viable waste treatment option.
Flowering plants possess specialized extracellular matrices in the female organs of the flower that support pollen tube growth and sperm cell transfer along the transmitting tract of the gynoecium. ...Transport of the pollen tube cell and the sperm cells involves a cell adhesion and migration event in species such as lily that possess a transmitting tract epidermis in the stigma, style, and ovary. A bioassay for adhesion was used to isolate from the lily stigma/stylar exudate the components that are responsible for in vivo pollen tube adhesion. At least two stylar components are necessary for adhesion: a large molecule and a small (9 kD) protein. In combination, the two molecules induced adhesion of pollen tubes to an artificial stylar matrix in vitro. The 9-kD protein was purified, and its corresponding cDNA was cloned. This molecule shares some similarity with plant lipid transfer proteins. Immunolocalization data support its role in facilitating adhesion of pollen tubes to the stylar transmitting tract epidermis.
Co-mixed simulant wasteforms consisting of calcined Magnox sludge simulant and clinoptilolite, with additions of a glass forming frit and CeO2 or U3O8 were processed using Hot Isostatic Pressing ...(HIP). This enabled the production of high waste loaded materials, with the successful incorporation of both simulant and active material. These formed heterogeneous glass-ceramic products, with decomposition of raw materials and some vitreous phase formation. The aqueous durability of these materials was assessed over a 28-day period using a modified PCT test, and favourably compared to the durability of an international glass. Overall this verifies the potential for HIP technology to be used in wasteform production, with potential large reductions in waste volume, especially if co-mixed wastes are considered.
Abstract Context Increasing interest in end-of-life care has resulted in many tools to measure the quality of care. An important outcome measure of end-of-life care is the family members' or ...caregivers' experiences of care. Objectives To evaluate the instruments currently in use to inform next steps for research and policy in this area. Methods We conducted a systematic review of PubMed, PsycINFO, and PsycTESTS® for all English-language articles published after 1990 using instruments to measure adult patient, family, or informal caregiver experiences with end-of-life care. Survey items were abstracted and categorized into content areas identified through an iterative method using three independent reviewers. We also abstracted information from the most frequently used surveys about the identification of proxy respondents for after-death surveys, the timing and method of survey administration, and the health care setting being assessed. Results We identified 88 articles containing 51 unique surveys with available content. We characterized 14 content areas variably present across the 51 surveys. Information and care planning, provider care, symptom management, and overall experience were the most frequent areas addressed. There was also considerable variation across the surveys in the identification of proxy respondents, the timing of survey administration, and in the health care settings and services being evaluated. Conclusion This review identified several comprehensive surveys aimed at measuring the experiences of end-of-life care, covering a variety of content areas and practical issues for survey administration. Future work should focus on standardizing surveys and administration methods so that experiences of care can be reliably measured and compared across care settings.
Vast areas of Europe were contaminated by the fallout of 137Cs and other radionuclides, as a result of the Chernobyl accident in 1986. The post-fallout redistribution of Chernobyl-derived 137Cs was ...associated with erosion and sediment transport processes within the fluvial system. Bottom sediments from lakes and reservoirs can provide a valuable source of information regarding the post-fallout redistribution and fate of 137Cs released by the Chernobyl accident. A detailed investigation of sediment-associated 137Cs in the bottom sediments of a reservoir in a Chernobyl-affected area in Central Russia has been undertaken. A new approach, based on the vertical distribution of 137Cs activity concentrations in the reservoir bottom sediment makes it possible to separate the initially deposited bottom sediment, where the 137Cs activity reflects the direct fallout of Chernobyl-derived 137Cs to the reservoir surface and its subsequent incorporation into sediment deposited immediately after the accident, from the sediment mobilized from the catchment deposited subsequently. The deposits representing direct fallout from the atmosphere was termed the “Chernobyl peak”. Its shape can be described by a diffusion equation and it can be distinguished from the remaining catchment-derived 137Cs associated with sediment accumulated with sediments during the post-Chernobyl period. The 137Cs depth distribution above the "Chernobyl peak" was used to provide a record of changes in the concentration of sediment-associated 137Cs transported from the upstream catchment during the post-Chernobyl period. It was found that the 137Cs activity concentration in the sediment deposited in the reservoir progressively decreased during the 30-year period after the accident due to a reduction in the contribution of sediment eroded from the arable land in the catchment. This reflects a reduction in both the area of cultivated land area and the reduced incidence of surface runoff from the slopes during spring snowmelt due to climate warming.
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•Reservoir bottom sediments provide a record of post-fallout redistribution of 137Cs.•The initial 137Cs fallout deposits can be distinguished in the absence of significant mixing.•The contribution of sediment eroded from arable lands declined since 1986.•Land-use and climate change contributed to the reduction of 137Cs activity in fluvial sediment.
X-ray absorption spectroscopy was applied to understand the speciation of elements relevant to the immobilisation and disposal of radioactive plutonium bearing wastes, utilizing Ce as a Pu surrogate. ...Ce L3 XANES (X-ray Absorption Near Edge Structure) characterisation of a crystallised glass material produced by cold crucible plasma vitrification, at demonstration scale, evidenced incorporation as Ce3+ within the glass phase, providing an important validation of laboratory scale studies. U and Ce L3 XANES investigation of brannerite ceramics, U0.9Ce0.1Ti2O6, synthesized under oxidizing, neutral and reducing conditions, established the charge compensation mechanism as incorporation of Ce3+ through formation of U5+ and/or U6+ In each of these examples, X-ray Absorption Spectroscopy has provided a pivotal understanding of element speciation in relation to the mechanism of incorporation within the host wasteform intended for geological disposal.
Genetic parameters for survival, reproduction and production traits were estimated for a sire and dam line, originating from one Large White breed separated more than 25 years ago. The change in ...parameters due to different selection pressure on reproduction and production traits in both lines was also examined. Data collected between 1990 and 2007 were available for the analysis of reproduction traits in 4713 litters (sire line) and 14836 litters (dam line) and for the production traits in 58329 pigs (sire line) and 108912 pigs (dam line). Genetic parameters were estimated using a Bayesian approach. Average phenotypic differences between lines were substantial with 1.5 more piglets born in the dam line and 1.7 mm less backfat thickness (BF) in the sire line. Based on a multiple trait analysis which included both reproduction and production traits, heritabilities for survival and litter size traits in the sire (or dam) line were estimated at 0.03 ± 0.01 (0.06 ± 0.01) for percentage of stillborn piglets (SB), 0.10 ± 0.03 (0.11 ± 0.01) for total number of piglets born (NBT) and 0.09 ± 0.03 (0.09 ± 0.01) for number of piglets born alive. Heritabilities for production traits were estimated at 0.29 ± 0.01 (0.29 ± 0.01) for average daily gain, 0.50 ± 0.01 (0.42 ± 0.01) for BF and 0.41 ± 0.01 for muscle depth. Selection pressure on litter size in the dam line resulted in a slightly unfavourable correlation for SB–NBT (0.21 ± 0.11), which was only marginally unfavourable in the sire line (0.06 ± 0.24). Selection pressure on BF in the sire line may have resulted in the moderately undesirable correlation with SB (−0.46 ± 0.15), which was not significant in the dam line (−0.08 ± 0.06). Changing the base population in the dam line to animals born since the year 2000 indicated that selection pressure on different traits has altered the heritabilities and correlations of the traits within the line. The undesirable correlations between survival at birth and reproduction traits or production traits were low so that simultaneous improvement of all traits can be achieved. Heritabilities for survival at birth and reproduction traits were low, but genetic variation was substantial and extensive pedigree information can be used to improve the accuracy of breeding values, so that genetic improvement is expected to be efficient.
In this study, binders within the system Mg(OH)
2
-NaAlO
2
-SiO
2
-H
2
O were produced and characterised for the potential immobilisation of radioactive Mg(OH)
2
sludges derived from the UK Magnox ...nuclear programme. The formation of zeolites promoted hardening within 24 h, with the structures and compositions of the zeolites dependent on the contents of SiO
2
in the systems. Limited consumption of Mg(OH)
2
was identified in the binders cured for up to 90 days, except for a hydrotalcite type layered double hydroxide in binders formulated with low SiO
2
contents. This study has elucidated that binders within this system can effectively encapsulate high contents of Mg(OH)
2
; however, the reaction of Mg(OH)
2
to form binding phases is limited by the content of SiO
2
in the system, and occurs primarily at advanced times of curing.
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