Prediction of remaining life of power transformers based on left truncated and right censored lifetime data

Prediction of the remaining life of high-voltage power transformers is an important issue for energy companies because of the need for planning maintenance and capital expenditures. Lifetime data for such transformers are complicated because transformer lifetimes can extend over many decades and transformer designs and manufacturing practices have evolved. We were asked to develop statistically-based predictions for the lifetimes of an energy company's fleet of high-voltage transmission and distribution transformers. The company's data records begin in 1980, providing information on installation and failure dates of transformers. Although the dataset contains many units that were installed before 1980, there is no information about units that were installed and failed before 1980. Thus, the data are left truncated and right censored. We use a parametric lifetime model to describe the lifetime distribution of individual transformers. We develop a statistical procedure, based on age-adjusted life distributions, for computing a prediction interval for remaining life for individual transformers now in service. We then extend these ideas to provide predictions and prediction intervals for the cumulative number of failures, over a range of time, for the overall fleet of transformers.Comment: Published in at http://dx.doi.org/10.1214/00-AOAS231 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Pilot trial of fk 506 in the management of steroid-resistant nephrotic syndrome

Seven patients with steroid-resistant nephrotic syndrome were treated with FK 506 monotherapy. Four patients were children with focal sclerosing glomerulonephritis (FSGS). Three of these had evldence for chronic progressive renal disease consisting of interstitial fibrosis and tubular atrophy on pretreatment renal biopsies. Two patients had also failed cyclosporin A (CsA), two cyclophosphamide, and one chlorambucil prior to treatment with FK 506. Three patients were adults wlth mesangial proliferative. membranoproliferative, and membranous glomerulonephritis. Three patterns of response were noted: (1) a reduction in proteinuria to normal levels, (2) partial response (50% reduction) or; (3) no improvement. All patients except one experienced at least a 50% reduction in protein excretion at some time during FK 506 therapy. Two of the children and one adult reduced protein excretion to essentially normal values. One patient had no sustained reduction In Droteln excretion and is considered to be a treatment fallure, although her protein excretion was approximately 50% of pretreatment values intermittently. The drug was generally well tolerated. The most common side-effect was nephrotoxlclty, whlch was reversible. These encouraging results suggest that FK 506 monotherapy may be effective in controlling the proteinuria of somc patlents with steroid-resistant nephrotic syndrome The use of this drug may extend our understanding of the role of T lymphocytes and cytokines in the pathogenesls of glomerulonephritis. Further study of this agent In a larger population of patlents is warranted. © 1993 European Dialysis and Transplant Assoiation-European Renal Association

Persuading consumers to reduce their consumption of electricity in the home

Previous work has identified that providing real time feedback or interventions to consumers can persuade consumers to change behaviour and reduce domestic electricity consumption. However, little work has investigated what exactly those feedback mechanisms should be. Most past work is based on an in-home display unit, possibly complemented by lower tariffs and delayed use of non-essential home appliances such as washing machines. In this paper we focus on four methods for real time feedback on domestic energy use, developed to gauge the impact on energy consumption in homes. Their feasibility had been tested using an experimental setup of 24 households collecting minute-by-minute electricity consumption data readings over a period of 18 months. Initial results are mixed, and point to the difficulties of sustaining a reduction in energy consumption, i.e. persuading consumers to change their behaviour. Some of the methods we used exploit small group social dynamics whereby people want to conform to social norms within groups they identify with. It may be that a variety of feedback mechanisms and interventions are needed in order to sustain user interest

Lightweight, Rack-Mountable Composite Cold Plate/Shelves

Rack-mountable composite-material structural components that would serve as both shelves and cold plates for removing heat from electronic or other equipment mounted on the shelves have been proposed as lightweight alternatives to all-metal cold plate/shelves now in use. A proposed cold plate/shelf would include a highly thermally conductive face sheet containing oriented graphite fibers bonded to an aluminum honeycomb core, plus an extruded stainless-steel substructure containing optimized flow passages for a cooling fluid, and an inlet and outlet that could be connected to standard manifold sections. To maximize heat-transfer efficiency, the extruded stainless-steel substructure would be connected directly to the face sheet. On the basis of a tentative design, the proposed composite cold plate/shelf would weigh about 38 percent less than does an all-aluminum cold plate in use or planned for use in some spacecraft and possibly aircraft. Although weight is a primary consideration, the tentative design offers the additional benefit of reduction of thickness to half that of the all-aluminum version

Comprehensive vs. Assisted Management of Mood and Pain Symptoms (CAMMPS) trial: Study design and sample characteristics

Background Pain is the most common presenting somatic symptom in medical outpatients, and depression and anxiety are the two most common mental disorders. They frequently co-occur, are under-treated, and result in substantial disability and reduced health-related quality of life. Objectives The Comprehensive vs. Assisted Management of Mood and Pain Symptoms (CAMMPS) study is a randomized comparative effectiveness trial designed to test the relative effectiveness of a lower-resource vs. a higher-resource technology-assisted intervention for the management of patients suffering from pain plus anxiety and/or depression. Methods/design CAMMPS has enrolled 294 primary care patients with chronic pain plus comorbid anxiety and/or depression and randomized them to either: 1) Assisted Symptom Management (ASM) consisting of automated symptom monitoring by interactive voice recording or Internet and prompted pain and mood self-management; or 2) Comprehensive Symptom Management (CSM) which combines ASM with optimized medication management delivered by a nurse-physician specialist team and facilitated mental health care. Outcomes are assessed at baseline, 1, 3, 6, and 12 months. The primary outcome is a composite pain-anxiety-depression (PAD) severity score. Secondary outcomes include individual pain, anxiety, and depression scores, health-related quality of life, disability, healthcare utilization, and treatment satisfaction. Discussion CAMMPS provides an integrated approach to PAD symptoms rather than fragmented care of single symptoms; coordinated symptom management in partnership with primary care clinicians and psychologists embedded in primary care; efficient use of health information technology; attention to physical and psychological symptom comorbidity; and the coupling of self-management with optimized medication management and facilitated mental health care

Elucidating the mitochondrial architecture of branched-chain amino acid metabolism enzymes: implications for treatment

Branched chain amino acid (BCAA) metabolism occurs within the mitochondrial matrix and is comprised of 17 enzymes, some shared, organized into three pathways for the catabolism of leucine, isoleucine, and valine (LEU, ILE, and VAL respectively). However, the physical relationships of the various enzymes in the pathways are unknown. Diseases such as isovaleric academia, propionic and methylmalonic acidemias, and maple syrup urine disease are among the disorders caused by genetic deficiencies of BCAA metabolism. I examined the BCAA pathways and their physical interactions in vitro through proteomics analysis and in situ using stimulated emission depletion microscopy. The functional interactions of the pathways were measured by flux analysis with labeled LEU, ILE, and VAL in patient and wild type cell lines, with quantification of the labeled metabolic end-products of each pathway. I examined novel potential treatments for propionic acidemia patient derived cell lines, quantitating protein, ROS production, and mitochondrial mass response to therapeutic agents. My proteomic and imaging studies are consistent with the existence of one or more energetically favorable, metabolite-channeling BCAA super-complex(es). Flux studies demonstrate that the end products of LEU, ILE and VAL metabolism are generated in both wild type and patient derived cells lines, implying cross-talk of BCAA pathways, and a close proximity of shared enzymes. Additionally, I found that the end-product of ILE and VAL, propionyl-CoA, does not readily enter the TCA cycle, as previously thought, while propionyl-CoA from odd chains fats does. Finally, propionyl-CoA carboxylase (PCC) deficient cell lines showed improved mitochondrial function when treated with a cardiolipin binding protein that stabilizes the inner mitochondrial membrane in cell cultures. PCC protein amount was slightly increased in treated patient cells, and ROS and mitochondrial mass was significantly decreased. These results provide novel insight into BCAA metabolism and offer new opportunities for the development of therapeutic agents for their defects. Furthermore, because propionyl-CoA derived from odd-chain fatty acids does, in fact, readily enter the TCA cycle, results from the metabolic flux studies will impact public health by changing potential therapies used to replenish the TCA cycle intermediates for disorders of fatty acid oxidation as well as BCAA metabolism

Human emotional response to energy visualisations

This is the post-print version of the final paper published in International Journal of Industrial Ergonomics. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2012 Elsevier B.V.Past research has found that frequent energy usage feedback is an important factor in reducing home energy consumption, and that the sensory appeal and cognitive relevance of the feedback are key components of user engagement with energy systems. The visual design of the information interface is important not just due to its role in communicating data of cognitive relevance, but also because the choice of information type and format is important towards achieving interactive Hebbian learning. The objective of the current research study was to investigate the possible effect of image format on the human emotional response to scenes of energy systems, and to evaluate whether any gender related differences in emotional response occurred. An automated PC-based test was developed which utilised five visual image formats (Optical Gray-Scale, Optical Coloured, Optical Augmented, Infrared Gray-Scale and Infrared Blue-Red) and nine home energy scenes (hot water boiler, radiator, water faucet, kitchen oven, tea kettle, toaster, electrical connector, laptop computer and tea mug). The emotional response of the participant was measured in the automated test by means of a Self-Assessment Manikin (SAM) which provided symbolic graphical representations of the human body under various degrees of emotional response, and associated Likert format rating scales for the valence and activation level of the emotional response. Comparison of the results obtained for the different visual scenes suggests that the greatest level of human emotional activation was achieved by the Infrared Blue-Red (thermal image) format, and that, generally, coloured images provided higher levels of emotional activation than gray-scale images. The increased activation achieved by the infrared images suggests attention capturing potential due to novelty, or due to the direct link to heat and energy, or both. Significant differences in emotional response (both activation and valence) were found to occur as a function of gender. The current results provide first guidance which a designer can use when choosing image spectrum and colours to represent energy systems on the displays of thermostats, smart meters and the energy devices. Relevance to industry - The current results provide first guidance which a designer can use when choosing image spectrum and colours to represent energy systems on the displays of thermostats, smart meters and the energy devices. Such design guidance is currently lacking internationally but is of increasing importance due to the expansion of digital devices, internet services and the upcoming internet-of-things