896 research outputs found
Southern California Edisonâs business case for transformer online monitoring
The Southern California Edison Company (SCE) operates a fleet of 285 HV and EHV substation power transformers. Failure of one of these banks can have a significant financial and operational impact. Online dissolved gas analyzers (DGA) and bushing monitors for power transformers
have become increasingly popular. The decision to apply online monitoring is usually driven by the criticality of the transformer and the consequence of an unplanned outage, whether lost production at a generator or industrial site or customer minutes lost within a utility network.
To reduce this risk, the strategic decision to equip the whole SCE fleet of EHV and HV transformers with online multi-gas, moisture, and bushing monitoring systems was made. This monitoring strategy is expected to result in:
⢠improved HV and EHV transformer reliability,
⢠reduced failure impacts,
⢠realization of complete transformer useful life, potentially several years beyond the nominal expected life,
⢠identification of units in urgent need of repair / replacement,
⢠early recognition of problems that the OEMâs warranty should cover,
⢠substantial reduction in overall transformer operating risks,
⢠improved accuracy of transformers health assessments.
Application of a comprehensive online DGA, moisture, and bushing monitoring strategy across Sothern California Edisonâs (SCEâs) fleet of EHV and HV transformers provides both technical and operational benefits to all stakeholders. A detailed business case and financial model have been developed to show that SCEâs online DGA strategy is also economically prudent
Southern California Edisonâs business case for transformer online monitoring
The Southern California Edison Company (SCE) operates a fleet of 285 HV and EHV substation power transformers. Failure of one of these banks can have a significant financial and operational impact. Online dissolved gas analyzers (DGA) and bushing monitors for power transformers
have become increasingly popular. The decision to apply online monitoring is usually driven by the criticality of the transformer and the consequence of an unplanned outage, whether lost production at a generator or industrial site or customer minutes lost within a utility network.
To reduce this risk, the strategic decision to equip the whole SCE fleet of EHV and HV transformers with online multi-gas, moisture, and bushing monitoring systems was made. This monitoring strategy is expected to result in:
⢠improved HV and EHV transformer reliability,
⢠reduced failure impacts,
⢠realization of complete transformer useful life, potentially several years beyond the nominal expected life,
⢠identification of units in urgent need of repair / replacement,
⢠early recognition of problems that the OEMâs warranty should cover,
⢠substantial reduction in overall transformer operating risks,
⢠improved accuracy of transformers health assessments.
Application of a comprehensive online DGA, moisture, and bushing monitoring strategy across Sothern California Edisonâs (SCEâs) fleet of EHV and HV transformers provides both technical and operational benefits to all stakeholders. A detailed business case and financial model have been developed to show that SCEâs online DGA strategy is also economically prudent
Forest Carbon Sequestration under the U.S. Biofuel Energy Policies
This paper analyzes impacts of the U.S. biofuel energy policies on the carbon sequestration by forest products, which is expressed as Harvested Wood Products (HWP) Contribution under the United Nations Framework Convention on Climate Change. Estimation for HWP Contribution is based on tracking carbon stock stored in wood and paper products in use and in solid-waste disposal sites (SWDS) from domestic consumption, harvests, imports, and exports. For this analysis, we hypothesize four alternative scenarios using the existing and pending U.S. energy policies by requirements for the share of biofuel to total energy consumption, and solve partial equilibrium for the U.S. timber market by 2030 for each scenario. The U.S. Forest Products Module (USFPM), created by USDA Forest Service Lab, operating within the Global Forest Products Model (GFPM) is utilized for projecting productions, supplies, and trade quantities for the U.S. timber market equilibrium. Based on those timber market components, we estimate scenario-specific HWP Contributions under the Production, the Stock Change, and the Atmospheric Approach suggested by Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories using WOODCARB II created by VTT Technical Research Centre of Finland and modified by USDA Forest Service Lab. Lastly, we compare estimated results across alternative scenarios. Results show that HWP Contributions for the baseline scenario in 2009 for all approaches are estimated higher than estimates reported by U.S. Environmental Protection Agency in 2011, (e.g., 22.64 Tg C/ year vs 14.80 Tg C/ year under the Production Approach), which is due to the economic recovery, especially in housing construction, assumed in USFPM/GFPM. Projected HWP Contribution estimates show that the Stock Change Approach, which used to provide the highest estimates before 2009, estimate HWP Contribution lowest after 2009 due to the declining annual net imports. Though fuel wood consumption is projected to be expanded as an alternative scenario requires higher wood fuel share to total energy consumption, the overall impacts on the expansion in other timber products are very modest across scenarios in USFPM/GFPM. Those negligible impacts lead to small differences of HWP Contribution estimates under all approaches across alternative scenarios. This is explained by the points that increasing logging residues are more crucial for expansion in fuel wood projections rather than the expansion of forest sector itself, and that the current HWP Contribution does not include carbon held in fuel wood products by its definition.Forest Products, Carbon Sequestration, Biofuel Policies, HWP Contribution, Resource /Energy Economics and Policy,
Geographical distribution of salmonella infected pig, cattle and sheep herds in Sweden 1993-2010
<p>Abstract</p> <p>Background</p> <p>The Swedish salmonella control programme covers the entire production chain, from feed to food. All salmonella serotypes are notifiable. On average, less than 20 cases of salmonella in food-producing animals are reported every year. In some situations, the cases would be expected to cluster geographically. The aim of this study was to illustrate the geographic distribution of the salmonella cases detected in pigs, cattle and sheep.</p> <p>Methods</p> <p>Data on all herds with pigs, cattle and sheep found to be infected with salmonella during the time period from 1993 to 2010 were obtained from the Swedish Board of Agriculture. Using the ArcGIS software, various maps were produced of infected herds, stratified on animal species as well as salmonella serotype. Based on ocular inspection of all maps, some were collapsed and some used separately. Data were also examined for temporal trends.</p> <p>Results</p> <p>No geographical clustering was observed for ovine or porcine cases. Cattle herds infected with Salmonella Dublin were mainly located in the southeast region and cattle herds infected with Salmonella Typhimurium in the most southern part of the country. Some seasonal variation was seen in cattle, but available data was not sufficient for further analyses.</p> <p>Conclusions</p> <p>Analyses of data on salmonella infected herds revealed some spatial and temporal patterns for salmonella in cattle. However, despite using 18 years' of data, the number of infected herds was too low for any useful statistical analyses.</p
Brain Gene Expression Signatures From Cerebrospinal Fluid Exosome RNA Profiling
While the Visual Impairment and Intracranial Pressure (VIIP) syndrome observations have focused on ocular symptoms, spaceflight has been also associated with a number of other performance and neurologic signs, such as headaches, cognitive changes, vertigo, nausea, sleep/circadian disruption and mood alterations, which, albeit likely multifactorial, can also result from elevation of intracranial pressure (ICP). We therefore hypothesize that these various symptoms are caused by disturbances in the neurophysiology of the brain structures and are correlated with molecular markers in the cerebrospinal fluid (CSF) as indicators of neurophysiological changes. Exosomes are 30-200 nm microvesicles shed into all biofluids, including blood, urine, and CSF, carrying a highly rich source of intact protein and RNA cargo. Exosomes have been identified in human CSF, and their proteome and RNA pool is a potential new reservoir for biomarker discovery in neurological disorders. The purpose of this study is to investigate changes in brain gene expression via exosome analysis in patients suffering from ICP elevation of varied severity (idiopathic intracranial hypertension -IIH), a condition which shares some of the neuroophthalmological features of VIIP, as a first step toward obtaining evidence suggesting that cognitive function and ICP levels can be correlated with biomarkers in the CSF. Our preliminary work, reported last year, validated the exosomal technology applicable to CSF analysis and demonstrated that it was possible to obtain gene expression evidence of inflammation processes in traumatic brain injury patients. We are now recruiting patients with suspected IIH requiring lumbar puncture at Baylor College of Medicine. Both CSF (5 ml) and human plasma (10 ml) are being collected in order to compare the pattern of differentially expressed genes observed in CSF and in blood. Since blood is much more accessible than CSF, we would like to determine whether plasma biomarkers for elevated ICP can be identified. This may eventually lead to a blood test to diagnose intracranial hypertension
Reflections on the role of publications by scientific societies in celebration of the 25th year for Acta Botanica Brasilica
TWO NEW SPECIES AND TWO NEW VARIETIES OF COLUMNEA (GESNERIACEAE)
In this paper two new species of Gesneriaceae (genus Columnea) are described and illustrated. Columnea chocoensis is distributed in the Colombian departments of ChocĂł and Valle del Cauca, while its variety, C. chocoensis var. altaquerensis is restricted to the Department of NariĂąo, Colombia. Columnea stilesiana was found in La SerranĂa de Los Paraguas located in the Cordillera Occidental between the ChocĂł and Valle del Cauca Departments in Colombia. Further, Columnea archidonae is here considered a variety of C. ericae; Columnea ericae var. archidonae is distributed in Colombia and Ecuador, in forests at elevations higher than those in which the typical variety is found
Columnea caudata and columnea megafolia, two new species of gesneriaceae
Two new species of Columnea belonging to section Collandra (Gesneriaceae) from the âcordillera Occidentalâ in the Colombian Andes are described and illustrated. Columnea caudata is distributed along the Biogeographical ChocĂł in the Departments of Antioquia, ChocĂł, Risaralda, and Valle del Cauca, whereas Columnea megafolia is restricted to Antioquia, and probably is an endemic species of the National Natural Park Las OrquĂdeas
Una nueva especie de columnea (gesneriaceae) del norte de los Andes
A new species of Columnea L. belonging to section Ortholoma (Gesneriaceae) from the Andean Region of Colombia and Ecuador is described.Se describe e ilustra una nueva especie de Columnea L. (Gesneriaceae) perteneciente a la secciĂłn Ortholoma. La nueva especie proviene de la regiĂłn andina de Colombia (CaquetĂĄ y Cauca) y Ecuador (Napo)
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