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Sample records for superfund site bucks

  1. Changes in Groundwater Flow and Volatile Organic Compound Concentrations at the Fischer and Porter Superfund Site, Warminster Township, Bucks County, Pennsylvania, 1993-2009

    Science.gov (United States)

    Sloto, Ronald A.

    2010-01-01

    The 38-acre Fischer and Porter Company Superfund Site is in Warminster Township, Bucks County, Pa. Historically, as part of the manufacturing process, trichloroethylene (TCE) degreasers were used for parts cleaning. In 1979, the Bucks County Health Department detected TCE and other volatile organic compounds (VOCs) in water from the Fischer and Porter on-site supply wells and nearby public-supply wells. The Fischer and Porter Site was designated as a Superfund Site and placed on the National Priorities List in September 1983. A 1984 Record of Decision for the site required the Fischer and Porter Company to pump and treat groundwater contaminated by VOCs from three on-site wells at a combined rate of 75 gallons per minute to contain groundwater contamination on the property. Additionally, the Record of Decision recognized the need for treatment of the water from two nearby privately owned supply wells operated by the Warminster Heights Home Ownership Association. In 2004, the Warminster Heights Home Ownership Association sold its water distribution system, and both wells were taken out of service. The report describes changes in groundwater levels and contaminant concentrations and migration caused by the shutdown of the Warminster Heights supply wells and presents a delineation of the off-site groundwater-contamination plume. The U.S. Geological Survey (USGS) conducted this study (2006-09) in cooperation with the U.S. Environmental Protection Agency (USEPA). The Fischer and Porter Site and surrounding area are underlain by sedimentary rocks of the Stockton Formation of Late Triassic age. The rocks are chiefly interbedded arkosic sandstone and siltstone. The Stockton aquifer system is comprised of a series of gently dipping lithologic units with different hydraulic properties. A three-dimensional lithostratigraphic model was developed for the site on the basis of rock cores and borehole geophysical logs. The model was simplified by combining individual lithologic

  2. Superfund Site Information

    Data.gov (United States)

    U.S. Environmental Protection Agency — This asset includes a number of individual data sets related to site-specific information for Superfund, which is governed under the Comprehensive Environmental...

  3. SITE COMPREHENSIVE LISTING (CERCLIS) (Superfund) - NPL Sites

    Data.gov (United States)

    U.S. Environmental Protection Agency — National Priorities List (NPL) Sites - The Comprehensive Environmental Response, Compensation and Liability Information System (CERCLIS) (Superfund) Public Access...

  4. Superfund Site Information - Site Sampling Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — This asset includes Superfund site-specific sampling information including location of samples, types of samples, and analytical chemistry characteristics of...

  5. Geohydrology and vertical distribution of volatile organic compounds in ground water, Fischer and Porter Company Superfund Site, Warminster, Bucks County, Pennsylvania

    Science.gov (United States)

    Sloto, R.A.; Macchiaroli, Paola; Conger, R.W.

    1995-01-01

    The Fischer and Porter company Superfund Site is underlain by sedimentary rocks of the Upper Triassic Stockton Formation, which consists of interbedded siltstone, very-fine grained to coarse-grained sandstone, and conglomerate in crudely defined upward fining cycles. These rocks form a complex, heterogeneous, leaky, multiaquifer system comprised of a series of gently dipping lithologic units with different hydraulic properties. Ground water is unconfined in the shallower part of the aquifer and confined or semiconfined in the deeper part of the aquifer. Water levels measured in monitor well clusters and borehole-flow measurements made in open boreholes show a downward hydraulic head gradient at the site, caused in part by the pumping of nearby, deep public-supply wells and the Fischer and Porter treatment system extraction wells. Downward borehole flow was measured at rates up to 9 gallons per minute. Aquifer-isolation tests were run in the six boreholes to obtain depth-discrete specific-capacity and water-quality data. On the basis of specific-capacity data for 27 isolated intervals, specific capacity is not related to depth. Water levels in monitor wells at the Fischer and Porter Site are greatly affected by the pumping of nearby public-supply wells, as well as the pumping of the Fischer and Porter treatment system extraction wells. Pumping of the public-supply wells causes daily water-level fluctuations in wells at the site as great as 5.3 feet. The shutdown of the Fischer and Porter treatment system extraction wells caused a rise in water level in all wells screened in the intermediate and deep zones. The rise in water level was as great as 4.3 feet in the intermediate zone and as great as 5.9 feet in the deep zone. The direction of ground-water flow is toward the north in the shallow and intermediate zones and toward the west and west-southwest in the deep zone. Ground-water discharge probably is to the unnamed tributary to Pennypack Creek north and west of

  6. Evaluation of borehole geophysical logging, aquifer-isolation tests, distribution of contaminants, and water-level measurements at the North Penn Area 5 Superfund Site, Bucks and Montgomery counties, Pennsylvania

    Science.gov (United States)

    Bird, Philip H.; Conger, Randall W.

    2002-01-01

    Borehole geophysical logging and aquiferisolation (packer) tests were conducted at the North Penn Area 5 Superfund site in Bucks and Montgomery Counties, Pa. Caliper, naturalgamma, single-point-resistance, fluid-temperature, fluid-resistivity, heatpulse-flowmeter, and digital acoustic-televiewer logs and borehole television surveys were collected in 32 new and previously drilled wells that ranged in depth from 68 to 302 feet. Vertical borehole-fluid movement direction and rate were measured with a high-resolution heatpulse flowmeter under nonpumping conditions. The suite of logs was used to locate water-bearing fractures, determine zones of vertical borehole- fluid movement, select depths to set packers, and locate appropriate screen intervals for reconstructing new wells as monitoring wells. Aquifer-isolation tests were conducted in four wells to sample discrete intervals and to determine specific capacities of discrete water-bearing zones. Specific capacities of isolated zones during packer testing ranged from 0.12 to 15.30 gallons per minute per foot. Most fractures identified by borehole geophysical methods as water-producing or water-receiving zones produced water when isolated and pumped. The acoustic-televiewer logs define two basic fracture sets, bedding-plane partings with a mean strike of N. 62? E. and a mean dip of 27? NW., and high-angle fractures with a mean strike of N. 58? E. and a mean dip of 72? SE. Correlation of heatpulse-flowmeter data and acoustic-televiewer logs showed 83 percent of identified water-bearing fractures were high-angle fractures.

  7. Superfund National Priority List (NPL) Site Boundaries

    Data.gov (United States)

    U.S. Environmental Protection Agency — A set of site boundaries for each site in EPA Region 1 (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont) on EPA's Superfund National...

  8. SITE COMPREHENSIVE LISTING (CERCLIS) (Superfund)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Comprehensive Environmental Response, Compensation and Liability Information System (CERCLIS) (Superfund) Public Access Database contains a selected set of...

  9. SITE COMPREHENSIVE LISTING (CERCLIS) (Superfund) - Non-NPL Sites

    Data.gov (United States)

    U.S. Environmental Protection Agency — Non-NPL Sites - The Comprehensive Environmental Response, Compensation and Liability Information System (CERCLIS) (Superfund) Public Access Database contains a...

  10. SITE COMPREHENSIVE LISTING (CERCLIS) - Contaminants at CERCLIS (Superfund) Sites

    Data.gov (United States)

    U.S. Environmental Protection Agency — Contaminants at Comprehensive Environmental Response, Compensation and Liability Information System (CERCLIS) (Superfund) Sites - The CERCLIS Public Access Database...

  11. SITE COMPREHENSIVE LISTING (CERCLIS) (Superfund) - Responsible Parties at CERCLIS Sites

    Data.gov (United States)

    U.S. Environmental Protection Agency — Responsible Parties at CERCLIS Sites - The Comprehensive Environmental Response, Compensation and Liability Information System (CERCLIS) (Superfund) Public Access...

  12. Region 9 NPL Sites (Superfund Sites) Polygons

    Data.gov (United States)

    U.S. Environmental Protection Agency — NPL site POLYGON locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...

  13. Region 9 NPL Sites (Superfund Sites 2013)

    Data.gov (United States)

    U.S. Environmental Protection Agency — NPL site POINT locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...

  14. Region 9 NPL Sites (Superfund Sites)

    Data.gov (United States)

    U.S. Environmental Protection Agency — NPL site POINT locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...

  15. Feasibility study for the United Heckathorn Superfund Site, Richmond, California

    Energy Technology Data Exchange (ETDEWEB)

    Lincoff, A.H. [US Environmental Protection Agency, San Francisco, CA (United States). Region IX; Costan, G.P.; Montgomery, M.S.; White, P.J. [Pacific Northwest Lab., Richland, WA (United States)

    1994-07-01

    The United Heckathom Superfund Site in Richmond, California, was used to formulate pesticides from approximately 1947 to 1966. Soils at the site and sediments in the harbor were contaminated with various chlorinated pesticides, primarily DDT, as a result of these activities. The US Environmental Protection Agency listed the site on the Superfund National Priorities List in 1990. This document is part of the Remedial Investigation and Feasibility Study phase of the Superfund response, which will provide the basis for selection of a final remedy that will protect human health and the environment and achieve compliance with federal and state envirorunental laws.

  16. Field analytical support during Superfund site remediation

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmidt, W.L.; Catherman, D.R. [Environmental Resources Management, Inc., Exton, PA (United States)

    1995-12-31

    ERM-FAST{reg_sign} Services has provided cost-effective and critical field analytical support for a wide variety of investigatory and remedial projects over the past four years. Two recent projects involving soils remediation at Superfund sites exemplify the power of real time field analytical support in reducing time and expense during a project`s remedial phase. ERM-FAST on-site analytical facilities were able to meet, in a real time scenario, all data quality objectives (DQOs), all regulatory agency requirements, and satisfied the client`s needs. ERM-FAST made this possible through the development of unique analytical strategies, the proper selection of analytical technologies, and by streamlining the analytical methodologies. Both of these remedial efforts offer illustrations of the effectiveness of field analysis for vastly differing site contaminants. This case study focuses on the use of portable Gas Chromatography (GC) instrumentation as a tool for providing analytical support during a CERCLA site remediation program. The project discussed provides an example of how low cost portable analytical instrumentation can be utilized in a field setting to meet analytical DQOs consistent with CERCLA compliance and to meet the requirements for remedial activity cost control. Substantial savings were realized both by reducing total project analytical cost, and by efficient and effective process and schedule management.

  17. 78 FR 13056 - Proposed CERCLA Administrative Cost Recovery Settlement; in re: Factory H Superfund Site, Meriden...

    Science.gov (United States)

    2013-02-26

    ... AGENCY Proposed CERCLA Administrative Cost Recovery Settlement; in re: Factory H Superfund Site, Meriden...)(1) concerning the Factory H Superfund Site in Meriden, Connecticut (``Site'') with the following... refer to the Factory H Superfund Site, U.S. EPA Docket No. CERCLA-01-2012-0112. FOR FURTHER...

  18. 77 FR 13603 - Anniston PCB Superfund Site; Anniston, Calhoun County, AL; Correction

    Science.gov (United States)

    2012-03-07

    ... AGENCY Anniston PCB Superfund Site; Anniston, Calhoun County, AL; Correction AGENCY: Environmental... concerning the Anniston PCB Superfund Site located in Anniston. The settlement is not an amendment, but a new... name Anniston PCB by one of the following methods:...

  19. 78 FR 729 - Ellman Battery Superfund Site; Orlando, Orange County, FL; Notice of Settlement

    Science.gov (United States)

    2013-01-04

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY Ellman Battery Superfund Site; Orlando, Orange County, FL; Notice of Settlement AGENCY... concerning a previous Removal Action at the Ellman Battery Superfund Site located in Orlando, Orange...

  20. 75 FR 53694 - Florida Petroleum Reprocessors Superfund Site; Davie, Broward County, FL; Notice of Settlement

    Science.gov (United States)

    2010-09-01

    ...] Florida Petroleum Reprocessors Superfund Site; Davie, Broward County, FL; Notice of Settlement AGENCY... Florida Petroleum Reprocessors Superfund Site located in Davie, Broward County, Florida for publication..., identified by Docket ID No. EPA-RO4- SFUND-2010-0729 or Site name Florida Petroleum Reprocessors Superfund...

  1. 77 FR 8255 - Constitution Road Drum Superfund Site, Atlanta, Dekalb County, GA; Notice of Settlement

    Science.gov (United States)

    2012-02-14

    ... AGENCY Constitution Road Drum Superfund Site, Atlanta, Dekalb County, GA; Notice of Settlement AGENCY... entered into a settlement for past response costs concerning the Constitution Road Drum Superfund Site... available from Ms. Paula V. Painter. Submit your comments by Site name Constitution Road Drum Superfund...

  2. Cleanups In My Community (CIMC) - Superfund National Priority List (NPL) Sites, National Layer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This data layer provides access to Superfund National Priority List Sites as part of the CIMC web service. Superfund is a program administered by the EPA to locate,...

  3. Remediation System Evaluation, Havertown PCP Superfund Site

    Science.gov (United States)

    The Havertown PCP site is located in Havertown, Haverford Township, Delaware County, in southeastern Pennsylvania. The site contamination was first discovered in 1962 when the Pennsylvania State Department of Health became aware of contaminants in ...

  4. 77 FR 11533 - Anniston PCB Superfund Site, Anniston, Calhoun County, Alabama; Notice of Amended Settlement

    Science.gov (United States)

    2012-02-27

    ... AGENCY Anniston PCB Superfund Site, Anniston, Calhoun County, Alabama; Notice of Amended Settlement... Agency has entered into a settlement for past response costs concerning the Anniston PCB Superfund Site... available from Ms. Paula V. Painter. Submit your comments by Site name Anniston PCB by one of the...

  5. 75 FR 81269 - Ward Transformer Superfund Site Raleigh, Wake County, NC; Notice of Settlements

    Science.gov (United States)

    2010-12-27

    ... AGENCY Ward Transformer Superfund Site Raleigh, Wake County, NC; Notice of Settlements AGENCY... Ward Transformer Superfund Site located in Raleigh, Wake County, North Carolina for publication. DATES... your comments, identified by Docket ID No. EPA-RO4- SFUND-2010-1053 or Site name Ward...

  6. 78 FR 14543 - Ward Transformer Superfund Site; Raleigh, Wake County, NC; Notice of Settlement

    Science.gov (United States)

    2013-03-06

    ... AGENCY Ward Transformer Superfund Site; Raleigh, Wake County, NC; Notice of Settlement AGENCY... Agency has entered into a settlement at the Ward Transformer Superfund Site located in Raleigh, Wake... EPA Region 4 contact Ms. Paula V. Painter. Submit your comments by Site name Ward...

  7. Remediation System Evaluation, McCormick and Baxter Superfund SiteRemediation System Evaluation, McCormick and Baxter Superfund Site

    Science.gov (United States)

    The McCormick and Baxter Creosoting Company, Portland Plant, Superfund Site is located adjacent tothe Willamette River in Portland, Oregon and addresses contamination of soil, groundwater, and riversediments stemming from creosoting operations...

  8. Remediation System Evaluation, Streamlined Remediation System Evaluation (RSE-Lite), Circuitron Corporation Superfund Site

    Science.gov (United States)

    The Circuitron Corporation Superfund Site is located at 82 Milbar Boulevard, East Farmingdale, Suffolk County, New York. The site is situated on a 1-acre lot in an industrial/commercial area that is surrounded by similar small manufacturers...

  9. Remediation of the Wells G & H Superfund Site, Woburn, Massachusetts.

    Science.gov (United States)

    Bair, E Scott; Metheny, Maura A

    2002-01-01

    Remediation of ground water and soil contamination at the Wells G & H Superfund Site, Woburn, Massachusetts, uses technologies that reflect differences in hydrogeologic settings, concentrations of volatile organic compounds (VOCs), and costs of treatment. The poorly permeable glacial materials that overlie fractured bedrock at the W.R. Grace property necessitate use of closely spaced recovery wells. Contaminated ground water is treated with hydrogen peroxide and ultraviolet (UV) oxidation. At UniFirst, a deep well completed in fractured bedrock removes contaminated ground water, which is treated by hydrogen peroxide, UV oxidation, and granular activated carbon (GAC). The remediation system at Wildwood integrates air sparging, soil-vapor extraction, and ground water pumping. Air stripping and GAC are used to treat contaminated water; GAC is used to treat contaminated air. New England Plastics (NEP) uses air sparging and soil-vapor extraction to remove VOCs from the unsaturated zone and shallow ground water. Contaminated air and water are treated using separate GAC systems. After nine years of operation at W.R. Grace and UniFirst, 30 and 786 kg, respectively, of VOCs have been removed. In three years of operation, 866 kg of VOCs have been removed at Wildwood. In 15 months of operation, 36 kg of VOCs were removed at NEP. Characterization work continues at the Olympia Nominee Trust, Whitney Barrel, Murphy Waste Oil, and Aberjona Auto Parts properties. Risk assessments are being finalized that address heavy metals in the floodplain sediments along the Aberjona River that are mobilized from the Industri-Plex Superfund Site located a few miles upstream.

  10. Superfund and Toxic Release Inventory Sites - MDC_ContaminatedSite

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — A point feature class of open DERM Contaminated sites - see phase code for status of site. Contaminated sites identifies properties where environmental contamination...

  11. Region 9 NPL Sites (Superfund Sites 2013) Polygons

    Data.gov (United States)

    U.S. Environmental Protection Agency — NPL site POLYGON locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...

  12. Superfund and Toxic Release Inventory Sites - MDC_ContaminatedSite

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — A point feature class of open DERM Contaminated sites - see phase code for status of site. Contaminated sites identifies properties where environmental contamination...

  13. Cleanups In My Community (CIMC) - Federal facilities that are also Superfund sites, National Layer

    Data.gov (United States)

    U.S. Environmental Protection Agency — Federal facilities are properties owned by the federal government. This data layer provides access to Federal facilities that are Superfund sites as part of the CIMC...

  14. Preliminary estimate of natural resource damage : Rocky Mountain Arsenal Superfund Site

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a preliminary estimate of natural resource damages associated with uncontrolled release of hazardous materials at the Rocky Mountain Arsenal Superfund Site...

  15. Cleanups In My Community (CIMC) - Base Realignment and Closure (BRAC) Superfund Sites, National Layer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This data layer provides access to Base Realignment and Closure (BRAC) Superfund Sites as part of the CIMC web service. EPA works with DoD to facilitate the reuse...

  16. EPA, 12 Private Entities Agree to Remove Contamination and Conduct Study at Metro Container Superfund Site

    Science.gov (United States)

    PHILADELPHIA (October 21, 2015) -- The U.S. Environmental Protection Agency and 12 private entities have agreed to settle on actions that will lead to increased environmental protection at the Metro Container Superfund Site in Trainer, Delaware Co.,

  17. Report: Remedial Project Manager Turnover at Superfund Sites

    Science.gov (United States)

    Report #2001-M-000015, June 15, 2001. We determined that EPA Region III did not have formal procedures in place to mitigate continuity problems caused by turnover of EPA personnel in the Superfund program.

  18. Air-water exchange of PAHs and OPAHs at a superfund mega-site.

    Science.gov (United States)

    Tidwell, Lane G; Blair Paulik, L; Anderson, Kim A

    2017-12-15

    Chemical fate is a concern at environmentally contaminated sites, but characterizing that fate can be difficult. Identifying and quantifying the movement of chemicals at the air-water interface are important steps in characterizing chemical fate. Superfund sites are often suspected sources of air pollution due to legacy sediment and water contamination. A quantitative assessment of polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAH (OPAHs) diffusive flux in a river system that contains a Superfund Mega-site, and passes through residential, urban and agricultural land, has not been reported before. Here, passive sampling devices (PSDs) were used to measure 60 polycyclic aromatic hydrocarbons (PAHs) and 22 oxygenated PAH (OPAHs) in air and water. From these concentrations the magnitude and direction of contaminant flux between these two compartments was calculated. The magnitude of PAH flux was greater at sites near or within the Superfund Mega-site than outside of the Superfund Mega-site. The largest net individual PAH deposition at a single site was naphthalene at a rate of -14,200 (±5780) (ng/m(2))/day. The estimated one-year total flux of phenanthrene was -7.9×10(5) (ng/m(2))/year. Human health risk associated with inhalation of vapor phase PAHs and dermal exposure to PAHs in water were assessed by calculating benzo[a]pyrene equivalent concentrations. Excess lifetime cancer risk estimates show potential increased risk associated with exposure to PAHs at sites within and in close proximity to the Superfund Mega-site. Specifically, estimated excess lifetime cancer risk associated with dermal exposure and inhalation of PAHs was above 1 in 1 million within the Superfund Mega-site. The predominant depositional flux profile observed in this study suggests that the river water in this Superfund site is largely a sink for airborne PAHs, rather than a source. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Superfund and Toxic Release Inventory Sites - SUPERFUND_IDEM_IN: Superfund Program Facilities in Indiana (Indiana Department of Environmental Management, Point Shapefile)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — SUPERFUND_IDEM_IN is a point shapefile that contains GPS-located Superfund Program facility locations in Indiana, provided by personnel of Indiana Department of...

  20. 76 FR 24479 - In the Matter of the Taylor Lumber and Treating Superfund Site, Sheridan, Oregon, Amendment to...

    Science.gov (United States)

    2011-05-02

    ... AGENCY In the Matter of the Taylor Lumber and Treating Superfund Site, Sheridan, Oregon, Amendment to... with PWPO provided a covenant not to sue for response costs at the Taylor Lumber and Treating Site... should reference the Taylor Lumber and Treating Superfund Site in Sheridan, Oregon, EPA Docket No....

  1. 78 FR 47317 - Ore Knob Mine Superfund Site; Laurel Springs, Ashe County, North Carolina; Notice of Settlement

    Science.gov (United States)

    2013-08-05

    ... AGENCY Ore Knob Mine Superfund Site; Laurel Springs, Ashe County, North Carolina; Notice of Settlement... Protection Agency has entered into a settlement with Herbert N. Francis concerning the Ore Knob Mine... comments by site name ``Ore Knob Mine Superfund Site'' by one of the following methods:...

  2. Spatial disparity in the distribution of superfund sites in South Carolina: an ecological study.

    Science.gov (United States)

    Burwell-Naney, Kristen; Zhang, Hongmei; Samantapudi, Ashok; Jiang, Chengsheng; Dalemarre, Laura; Rice, LaShanta; Williams, Edith; Wilson, Sacoby

    2013-11-06

    According to the US Environmental Protection Agency (EPA), Superfund is a federal government program implemented to clean up uncontrolled hazardous waste sites. Twenty-six sites in South Carolina (SC) have been included on the National Priorities List (NPL), which has serious human health and environmental implications. The purpose of this study was to assess spatial disparities in the distribution of Superfund sites in SC. The 2000 US census tract and block level data were used to generate population characteristics, which included race/ethnicity, socioeconomic status (SES), education, home ownership, and home built before 1950. Geographic Information Systems (GIS) were used to map Superfund facilities and develop choropleth maps based on the aforementioned sociodemographic variables. Spatial methods, including mean and median distance analysis, buffer analysis, and spatial approximation were employed to characterize burden disparities. Regression analysis was performed to assess the relationship between the number of Superfund facilities and population characteristics. Spatial coincidence results showed that of the 29.5% of Blacks living in SC, 55.9% live in Superfund host census tracts. Among all populations in SC living below poverty (14.2%), 57.2% were located in Superfund host census tracts. Buffer analyses results (0.5mi, 1.0mi, 5.0mi, 0.5km, 1.0km, and 5.0km) showed a higher percentage of Whites compared to Blacks hosting a Superfund facility. Conversely, a slightly higher percentage of Blacks hosted (30.2%) a Superfund facility than those not hosting (28.8%) while their White counterparts had more equivalent values (66.7% and 67.8%, respectively). Regression analyses in the reduced model (Adj. R2 = 0.038) only explained a small percentage of the variance. In addition, the mean distance for percent of Blacks in the 90th percentile for Superfund facilities was 0.48mi. Burden disparities exist in the distribution of Superfund facilities in SC at the block and

  3. 75 FR 68788 - Ore Knob Mine Superfund Site; Jefferson, Ashe County, North Carolina; Notice of Settlement

    Science.gov (United States)

    2010-11-09

    ... Doc No: 2010-28260] ENVIRONMENTAL PROTECTION AGENCY [Docket EPA-RO4-SFUND-2010-0893, FRL-9223-8] Ore... Protection Agency has entered into a settlement for reimbursement of past response costs concerning the Ore..., identified by Docket ID No. EPA-RO4- SFUND-2010-0893 or Site name Ore Knob Mine Superfund Site by one of...

  4. 77 FR 16548 - Florida Petroleum Reprocessors Superfund Site; Davie, Broward County, FL; Notice of Settlements

    Science.gov (United States)

    2012-03-21

    ...] Florida Petroleum Reprocessors Superfund Site; Davie, Broward County, FL; Notice of Settlements AGENCY... entered into four (4) settlements for past response costs concerning the Florida Petroleum Reprocessors... settlement are available from Ms. Paula V. Painter. Submit your comments by Site name Florida Petroleum...

  5. 77 FR 2981 - Constitution Road Drum Superfund Site; Atlanta, Dekalb County, GA; Notice of Settlement

    Science.gov (United States)

    2012-01-20

    ... AGENCY Constitution Road Drum Superfund Site; Atlanta, Dekalb County, GA; Notice of Settlement AGENCY... Protection Agency has entered into a settlement for past response costs concerning the Constitution Road Drum... settlement are available from Ms. Paula V. Painter. Submit your comments by Site name Constitution Road...

  6. Medical costs and lost productivity from health conditions at volatile organic compound-contaminated Superfund sites

    Energy Technology Data Exchange (ETDEWEB)

    Lybarger, J.A.; Spengler, R.F.; Brown, D.R. [Agency for Toxic Substances and Disease Registry, Atlanta, GA (United States). Div. of Health Studies; Lee, R.; Vogt, D.P. [Oak Ridge National Lab., TN (United States)]|[Joint Inst. for Energy and Environment, Oak Ridge, TN (United States); Perhac, R.M. Jr. [Univ. of Tennessee, Knoxville, TN (United States)]|[Joint Inst. for Energy and Environment, Oak Ridge, TN (United States)

    1998-10-01

    This paper estimates the health costs at Superfund sites for conditions associated with volatile organic compounds (VOCs) in drinking water. Health conditions were identified from published literature and registry information as occurring at excess rates in VOC-exposed populations. These health conditions were: (1) some categories of birth defects, (2) urinary tract disorders, (3) diabetes, (4) eczema and skin conditions, (5) anemia, (6) speech and hearing impairments in children under 10 years of age, and (7) stroke. Excess rates were used to estimate the excess number of cases occurring among the total population living within one-half mile of 258 Superfund sites. These sites had evidence of completed human exposure pathways for VOCs in drinking water. For each type of medical condition, an individual`s expected medical costs, long-term care costs, and lost work time due to illness or premature mortality were estimated. Costs were calculated to be approximately $330 million per year, in the absence of any remediation or public health intervention programs. The results indicate the general magnitude of the economic burden associated with a limited number of contaminants at a portion of all Superfund sites, thus suggesting that the burden would be greater than that estimated in this study if all contaminants at all Superfund sites could be taken into account.

  7. A General Chemistry Assignment Analyzing Environmental Contamination for the Depue, IL, National Superfund Site

    Science.gov (United States)

    Saslow Gomez, Sarah A.; Faurie-Wisniewski, Danielle; Parsa, Arlen; Spitz, Jeff; Spitz, Jennifer Amdur; Loeb, Nancy C.; Geiger, Franz M.

    2015-01-01

    The classroom exercise outlined here is a self-directed assignment that connects students to the environmental contamination problem surrounding the DePue Superfund site. By connecting chemistry knowledge gained in the classroom with a real-world problem, students are encouraged to personally connect with the problem while simultaneously…

  8. A General Chemistry Assignment Analyzing Environmental Contamination for the Depue, IL, National Superfund Site

    Science.gov (United States)

    Saslow Gomez, Sarah A.; Faurie-Wisniewski, Danielle; Parsa, Arlen; Spitz, Jeff; Spitz, Jennifer Amdur; Loeb, Nancy C.; Geiger, Franz M.

    2015-01-01

    The classroom exercise outlined here is a self-directed assignment that connects students to the environmental contamination problem surrounding the DePue Superfund site. By connecting chemistry knowledge gained in the classroom with a real-world problem, students are encouraged to personally connect with the problem while simultaneously…

  9. Biomonitoring for metal contamination near two Superfund sites in Woburn, Massachusetts, using phytochelatins

    Energy Technology Data Exchange (ETDEWEB)

    Gawel, James E.; Hemond, Harold F

    2004-09-01

    Characterizing the spatial extent of groundwater metal contamination traditionally requires installing sampling wells, an expensive and time-consuming process in urban areas. Moreover, extrapolating biotic effects from metal concentrations alone is problematic, making ecological risk assessment difficult. Our study is the first to examine the use of phytochelatin measurements in tree leaves for delimiting biological metal stress in shallow, metal-contaminated groundwater systems. Three tree species (Rhamnus frangula, Acer platanoides, and Betula populifolia) growing above the shallow groundwater aquifer of the Aberjona River watershed in Woburn, Massachusetts, display a pattern of phytochelatin production consistent with known sources of metal contamination and groundwater flow direction near the Industri-Plex Superfund site. Results also suggest the existence of a second area of contaminated groundwater and elevated metal stress near the Wells G and H Superfund site downstream, in agreement with a recent EPA ecological risk assessment. Possible contamination pathways at this site are discussed.

  10. Report: Independent Ground Water Sampling Generally Confirms EPA’s Data at Wheeler Pit Superfund Site in Wisconsin

    Science.gov (United States)

    Report #10-P-0218, September 8, 2010. With minimal exceptions, our independent sampling results at the Wheeler Pit Superfund Site were consistent with the sampling results that EPA Region 5 has obtained historically.

  11. Issuance of Final Guidance: Ecological Risk Assessment and Risk Management Principles for Superfund Sites, October 7, 1999

    Science.gov (United States)

    This guidance is intended to help Superfund risk managers make ecological risk management decisions that are based on sound science, consistent across Regions, and present a characterization of site risks that is transparent to the public.

  12. Electrochemical peroxidation of PCBs and VOCs in superfund site water and sediments

    Energy Technology Data Exchange (ETDEWEB)

    Scrudato, R.J.; Chiarenzelli, J.R. [SUNY, Oswego, NY (United States)

    1996-12-31

    An electrochemical peroxidation (ECP) process has been developed and used to degrade polychlorinated biphenyls (PCB) and volatile organic compounds (VOC)-contaminated water, sludge, and sediments at a New York State Federal and State Superfund Site. The process involves passing an oscillating low-amperage (<10 amps) current through steel electrodes immersed in an acidified water or sediment slurry into which hydrogen peroxide (<1,000 ppm) is added. The generated free radicals attack organic compounds, including organo-metallic complexes and refractory compounds including PCBs. PCB degradation ranged from about 30% to 80% in experiments involving Federal Superfund Site sediments; total PCBs were reduced by {approximately}97% to 68%, respectively, in water and slurry collected from a State Superfund subsurface storage tank. VOC bench-scale experiments involved chloroethane, 1,1-dichloroethane, dichloromethane, 1,1,1-trichloroethane, and acetone and after a 3-min ECP treatment, degradation ranged from >94% to about 99.9%. Results indicate the ECP is a viable process to degrade organic contaminants in water and sediment suspensions. Because the treated water suspensions are acidified, select trace metal sorbed to the particulates is solubilized and therefore can be segregated from the particulates, offering a process that simultaneously degrades organic contaminants and separates trace metals. 19 refs., 1 fig., 4 tabs.

  13. Aquatic assessment of the Ely Copper Mine Superfund site, Vershire, Vermont

    Science.gov (United States)

    Seal, Robert R.; Kiah, Richard G.; Piatak, Nadine M.; Besser, John M.; Coles, James F.; Hammarstrom, Jane M.; Argue, Denise M.; Levitan, Denise M.; Deacon, Jeffrey R.; Ingersoll, Christopher G.

    2010-01-01

    The Ely Mine, which operated from 1821 to 1905, and its area of downstream impact constitute the Ely Copper Mine Superfund site. The site was placed on the National Priorities List in 2001. The mine comprises underground workings, foundations from historical structures, several waste-rock piles, roast beds associated with the smelting operation, and slag piles resulting from the smelting. The mine site is drained by Ely Brook, which includes several tributaries, one of which drains a series of six ponds. Ely Brook empties into Schoolhouse Brook, which flows 3.3 kilometers and joins the Ompompanoosuc River.

  14. Geophysical logging at the Cristex Drum National Priorities List Superfund Site near Oxford, North Carolina

    Science.gov (United States)

    Antolino, Dominick J.

    2017-01-01

    The collection of borehole geophysical logs data was conducted by the U.S. Geological Survey South Atlantic Water Science Center in the vicinity of the Cristex Drum National Priorities List Superfund Site near Oxford, North Carolina, during January through March 2016. In an effort to assist the U.S. Environmental Protection Agency in the development of a conceptual groundwater model for the assessment of current contaminant distribution and future migration of contaminants, borehole geophysical log and image data collection, which included the delineation of more than 150 subsurface features (primarily fracture orientations) in 3 open borehole wells.

  15. Surface geophysics and porewater evaluation at the Lower Darby Creek Area Superfund Site, Philadelphia, Pennsylvania, 2013

    Science.gov (United States)

    Walker, Charles W.; Degnan, James R.; Brayton, Michael J.; Cruz, Roberto M.; Lorah, Michelle M.

    2015-01-01

    In cooperation with the U.S. Environmental Protection Agency (EPA), Region 3, the U.S. Geological Survey (USGS) is participating in an ongoing study to aid in the identification of subsurface heterogeneities that may act as preferential pathways for contaminant transport in and around the Lower Darby Creek Area (LDCA) Superfund Site, Philadelphia Pa. Lower Darby Creek, which flows into the Delaware River, borders the western part of the former landfill site. In 2013, the USGS conducted surface geophysics measurements and stream porewater sampling to provide additional data for EPA’s site characterization. This report contains data collected from field measurements of direct current (DC) resistivity, frequency-domain electromagnetic (FDEM) surveys, and stream porewater specific conductance (SC).

  16. Continued geophysical logging near the GMH Electronics National Priorities List Superfund site near Roxboro, North Carolina

    Science.gov (United States)

    Antolino, Dominick J.; Chapman, Melinda J.

    2017-01-06

    The U.S. Geological Survey South Atlantic Water Science Center collected borehole geophysical logs and images and continuous water-level data near the GMH Electronics National Priorities List Superfund site near Roxboro, North Carolina, during December 2012 through July 2015. Previous work by the U.S. Geological Survey South Atlantic Water Science Center at the site involved the collection of borehole geophysical log data in 15 wells, in addition to surface geologic mapping and passive diffusion bag sampling. In a continued effort to assist the U.S. Environmental Protection Agency in developing a conceptual groundwater model to assess current contaminant distribution and future migration of contaminants, more than 900 subsurface features (primarily fracture orientations) in 10 open borehole wells were delineated and continuous water-level data information from 14 monitoring wells within close proximity of the initially drilled boreholes was collected to observe any induced water-level fluctuations during drilling operations

  17. ASSESSMENT OF VAPOR INTRUSION IN HOMES NEAR THE RAYMARK SUPERFUND SITE USING BASEMENT AND SUB-SLAB AIR SAMPLES

    Science.gov (United States)

    This report describes the results of an investigation conducted to assist EPA’s New England Regional Office in evaluating vapor intrusion at 15 homes and one commercial building near the Raymark Superfund Site in Stratford, Connecticut. Methods were developed to sample sub-slab ...

  18. Mining-related sediment and soil contamination in a large Superfund site: Characterization, habitat implications, and remediation

    Science.gov (United States)

    Juracek, Kyle E.; Drake, K. D.

    2016-01-01

    Historical mining activity (1850–1970) in the now inactive Tri-State Mining District provided an ongoing source of lead and zinc to the environment including the US Environmental Protection Agency Superfund site located in Cherokee County, southeast Kansas, USA. The resultant contamination adversely affected biota and caused human health problems and risks. Remediation in the Superfund site requires an understanding of the magnitude and extent of contamination. To provide some of the required information, a series of sediment and soil investigations were conducted in and near the Superfund site to characterize lead and zinc contamination in the aquatic and floodplain environments along the main-stem Spring River and its major tributaries. In the Superfund site, the most pronounced lead and zinc contamination, with concentrations that far exceed sediment quality guidelines associated with potential adverse biological effects, was measured for streambed sediments and floodplain soils located within or downstream from the most intensive mining-affected areas. Tributary streambeds and floodplains in affected areas are heavily contaminated with some sites having lead and zinc concentrations that are an order of magnitude (or more) greater than the sediment quality guidelines. For the main-stem Spring River, the streambed is contaminated but the floodplain is mostly uncontaminated. Measured lead and zinc concentrations in streambed sediments, lakebed sediments, and floodplain soils documented a persistence of the post-mining contamination on a decadal timescale. These results provide a basis for the prioritization, development, and implementation of plans to remediate contamination in the affected aquatic and floodplain environments within the Superfund site.

  19. Mining-Related Sediment and Soil Contamination in a Large Superfund Site: Characterization, Habitat Implications, and Remediation.

    Science.gov (United States)

    Juracek, K E; Drake, K D

    2016-10-01

    Historical mining activity (1850-1970) in the now inactive Tri-State Mining District provided an ongoing source of lead and zinc to the environment including the US Environmental Protection Agency Superfund site located in Cherokee County, southeast Kansas, USA. The resultant contamination adversely affected biota and caused human health problems and risks. Remediation in the Superfund site requires an understanding of the magnitude and extent of contamination. To provide some of the required information, a series of sediment and soil investigations were conducted in and near the Superfund site to characterize lead and zinc contamination in the aquatic and floodplain environments along the main-stem Spring River and its major tributaries. In the Superfund site, the most pronounced lead and zinc contamination, with concentrations that far exceed sediment quality guidelines associated with potential adverse biological effects, was measured for streambed sediments and floodplain soils located within or downstream from the most intensive mining-affected areas. Tributary streambeds and floodplains in affected areas are heavily contaminated with some sites having lead and zinc concentrations that are an order of magnitude (or more) greater than the sediment quality guidelines. For the main-stem Spring River, the streambed is contaminated but the floodplain is mostly uncontaminated. Measured lead and zinc concentrations in streambed sediments, lakebed sediments, and floodplain soils documented a persistence of the post-mining contamination on a decadal timescale. These results provide a basis for the prioritization, development, and implementation of plans to remediate contamination in the affected aquatic and floodplain environments within the Superfund site.

  20. Mining-Related Sediment and Soil Contamination in a Large Superfund Site: Characterization, Habitat Implications, and Remediation

    Science.gov (United States)

    Juracek, K. E.; Drake, K. D.

    2016-10-01

    Historical mining activity (1850-1970) in the now inactive Tri-State Mining District provided an ongoing source of lead and zinc to the environment including the US Environmental Protection Agency Superfund site located in Cherokee County, southeast Kansas, USA. The resultant contamination adversely affected biota and caused human health problems and risks. Remediation in the Superfund site requires an understanding of the magnitude and extent of contamination. To provide some of the required information, a series of sediment and soil investigations were conducted in and near the Superfund site to characterize lead and zinc contamination in the aquatic and floodplain environments along the main-stem Spring River and its major tributaries. In the Superfund site, the most pronounced lead and zinc contamination, with concentrations that far exceed sediment quality guidelines associated with potential adverse biological effects, was measured for streambed sediments and floodplain soils located within or downstream from the most intensive mining-affected areas. Tributary streambeds and floodplains in affected areas are heavily contaminated with some sites having lead and zinc concentrations that are an order of magnitude (or more) greater than the sediment quality guidelines. For the main-stem Spring River, the streambed is contaminated but the floodplain is mostly uncontaminated. Measured lead and zinc concentrations in streambed sediments, lakebed sediments, and floodplain soils documented a persistence of the post-mining contamination on a decadal timescale. These results provide a basis for the prioritization, development, and implementation of plans to remediate contamination in the affected aquatic and floodplain environments within the Superfund site.

  1. Raman spectroscopy of efflorescent sulfate salts from Iron Mountain Mine Superfund Site, California.

    Science.gov (United States)

    Sobron, Pablo; Alpers, Charles N

    2013-03-01

    The Iron Mountain Mine Superfund Site near Redding, California, is a massive sulfide ore deposit that was mined for iron, silver, gold, copper, zinc, and pyrite intermittently for nearly 100 years. As a result, both water and air reached the sulfide deposits deep within the mountain, producing acid mine drainage consisting of sulfuric acid and heavy metals from the ore. Particularly, the drainage water from the Richmond Mine at Iron Mountain is among the most acidic waters naturally found on Earth. The mineralogy at Iron Mountain can serve as a proxy for understanding sulfate formation on Mars. Selected sulfate efflorescent salts from Iron Mountain, formed from extremely acidic waters via drainage from sulfide mining, have been characterized by means of Raman spectroscopy. Gypsum, ferricopiapite, copiapite, melanterite, coquimbite, and voltaite are found within the samples. This work has implications for Mars mineralogical and geochemical investigations as well as for terrestrial environmental investigations related to acid mine drainage contamination.

  2. Raman spectroscopy of efflorescent sulfate salts from Iron Mountain Mine Superfund Site, California

    Science.gov (United States)

    Sobron, Pablo; Alpers, Charles N.

    2013-01-01

    The Iron Mountain Mine Superfund Site near Redding, California, is a massive sulfide ore deposit that was mined for iron, silver, gold, copper, zinc, and pyrite intermittently for nearly 100 years. As a result, both water and air reached the sulfide deposits deep within the mountain, producing acid mine drainage consisting of sulfuric acid and heavy metals from the ore. Particularly, the drainage water from the Richmond Mine at Iron Mountain is among the most acidic waters naturally found on Earth. The mineralogy at Iron Mountain can serve as a proxy for understanding sulfate formation on Mars. Selected sulfate efflorescent salts from Iron Mountain, formed from extremely acidic waters via drainage from sulfide mining, have been characterized by means of Raman spectroscopy. Gypsum, ferricopiapite, copiapite, melanterite, coquimbite, and voltaite are found within the samples. This work has implications for Mars mineralogical and geochemical investigations as well as for terrestrial environmental investigations related to acid mine drainage contamination.

  3. Fishing a superfund site: Dissonance and risk perception of environmental hazards by fishermen in Puerto Rico

    Energy Technology Data Exchange (ETDEWEB)

    Burger, J.; Gochfeld, M. (Rutgers University, Piscataway, NJ (USA))

    1991-06-01

    Risk perception studies show that individuals tend to underestimate significant risks, overestimate negligible ones, and distrust authorities. They also rely on a variety of strategies or heuristics to reach decisions regarding their risk-taking behavior. The authors report on a survey of fishermen and crabbers engaged in recreational and substance fishing in a Puerto Rican estuary (near Humacao), which has been declared a Superfund site because of suspected contamination by mercury, and at ecologically similar control sites. Nearly everyone interviewed at the Humacao site was aware of the mercury contamination, but either denied its importance, believed the contamination was restricted to a distant part of the estuary, or assumed that the estuary would be closed by the authorities if the threat was real. All site-users consumed the fish and crabs they caught. At Humacao, the average catch was 7 fish per fishermen (mostly tilapia, Tilapia mossambica, and tarpon, Megalops atlantica) and 13 crabs per crabber (all blue crabs, Callinectes sapidus). On average, the site-users returned to the lagoons about 3-4 times per month. At control sites, fewer fish were eaten. The worst case consumption of tarpon, a species which concentrated mercury at Eastern Puerto Rico, provided an exposure exceeding the EPA reference dose, whereas consumption of one tarpon per week did not entail excess exposure. Fortunately, few individuals caught tarpon exclusively. Unlike counterparts in the northeastern United States, they trusted authorities and indicated that they would have heeded warnings of mercury contamination posted where they fished.

  4. Superfund and Toxic Release Inventory Sites, StateCERCLIS-This data set contains potential EPA Superfund sites. These locations represent sites, not contaminated areas., Published in 2008, 1:100000 (1in=8333ft) scale, State of Utah Automated Geographic Reference Center.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Superfund and Toxic Release Inventory Sites dataset, published at 1:100000 (1in=8333ft) scale, was produced all or in part from Field Survey/GPS information as...

  5. Environmental contaminants in fish and mussels from Meddybemps Lake, the Dennys River, and East Machias River - Eastern Surplus Superfund Site, Meddybemps, Maine

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — From 1946 to the early 1980s, the 3-acre Eastern Surplus Superfund Site in Meddybemps, Maine, was used for the disposal and storage of surplus military equipment and...

  6. Integrating Monitoring and Genetic Methods To Infer Historical Risks of PCBs and DDE to Common and Roseate Terns Nesting Near the New Bedford Harbor Superfund Site (Massachusetts, USA)

    Science.gov (United States)

    Common and roseate terns are migratory piscivorous seabirds with major breeding colonies within feeding range of thepolychlorinated biphenyl (PCB)-contaminated New Bedford Harbor (NBH, MA, USA) Superfund site. Our longitudinal study shows that before PCB discharges into NBH cease...

  7. Evaluation of Exposure to Radon Levels in Relation to Climatic Conditions at a Superfund Site.

    Science.gov (United States)

    Merrill, Elaine Alice

    1995-11-01

    Workers at a Superfund site have expressed concern that they may be exposed to elevated levels of radon gas, especially when meteorology is suitable. The site, formally a uranium processing site, stores the world's largest quantity of Ra-226 in two concrete silos. A layer of bentonite foam was placed over the contents of the silos in 1991 as a means to reduce the amount of radon emissions. Hourly real-time outdoor and indoor site radon data covering an entire year was statistically evaluated in relation to meteorological data covering the same time period. The hourly data was found to be lognormally distributed. Radon levels were highest during the early morning hours and during the summer months. Both outdoor and indoor concentrations were found to significantly vary with temporal and climatic factors, namely wind direction and relative humidity. Radon levels in the work areas were not found to be statistically different from off-site levels. Only radon levels in the vicinity of the storage silos, which is an exclusion zone, were significantly higher than levels off-site. Hence, the protective bentonite covering seems to be effective in reducing radon emissions. Two methods were used to calculate a hypothetical dose, based upon the annual average concentrations of radon in the work areas onsite, the BEIR IV method and the NCRP method, respectively. The BEIR IV method, which accounts for the activity ratio of radon and its daughter products, resulted in a slightly higher dose than the NCRP method. As expected, based on the mean concentrations, the hypothetical annual exposures from radon in the work areas of the site were below recommended exposure limits.

  8. Characterization of ecological risks at the Milltown Reservoir-Clark Fork River Sediments Superfund Site, Montana

    Science.gov (United States)

    Pascoe, Gary A.; Blanchet, Richard J.; Linder, Greg L.; Palawski, Don; Brumbaugh, William G.; Canfield, Tim J.; Kemble, Nile E.; Ingersoll, Chris G.; Farag, Aïda M.; DalSoglio, Julie A.

    1994-01-01

    A comprehensive field and laboratory approach to the ecological risk assessment for the Milltown Reservoir-Clark Fork River Sediments Site, a Superfund site in the Rocky Mountains of Montana, has been described in the preceding reports of this series. The risk assessment addresses concerns over the ecological impacts of upstream releases of mining wastes to fisheries of the upper Clark Fork River (CFR) and the benthic and terrestrial habitats further downstream in Milltown Reservoir. The risk characterization component of the process integrated results from a triad of information sources: (a) chemistry studies of environmental media to identify and quantify exposures of terrestrial and aquatic organisms to site-related contaminants; (b) ecological or population studies of terrestrial vegetation, birds, benthic communities, and fish; and (c) in situ and laboratory toxicity studies with terrestrial and aquatic invertebrates and plants, small mammals, amphibians, and fish exposed to contaminated surface water, sediments, wetland soils, and food sources. Trophic transfer studies were performed on waterfowl, mammals, and predatory birds using field measurement data on metals concentrations in environmental media and lower trophic food sources. Studies with sediment exposures were incorporated into the Sediment Quality Triad approach to evaluate risks to benthic ecology. Overall results of the wetland and terrestrial studies suggested that acute adverse biological effects were largely absent from the wetland; however, adverse effects to reproductive, growth, and physiological end points of various terrestrial and aquatic species were related to metals exposures in more highly contaminated depositional areas. Feeding studies with contaminated diet collected from the upper CFR indicated that trout are at high risk from elevated metals concentrations in surface water, sediment, and aquatic invertebrates. Integration of chemical analyses with toxicological and ecological

  9. Evaluation of geophysical logs, phase I, for Crossley Farms Superfund Site, Berks County, Pennsylvania

    Science.gov (United States)

    Conger, Randall W.

    1998-01-01

    Twenty-one wells were drilled at Crossley Farms Superfund Site between December 15, 1987, and May 1, 1988, to define and monitor the horizontal and vertical distribution of ground-water contamination emanating from a suspected contaminant source area (Blackhead Hill). Eight well clusters were drilled on or near the Crossley Site and three well clusters were drilled at locations hydrologically down gradient from the site. Depths of wells range from 21 to 299 feet below land surface. These wells were installed in saprolite in shallow, intermediate, and deep water-producing zones of the fractured bedrock aquifer. Borehole-geophysical and video logging were conducted between April 24, 1997, and May 8, 1997, to determine the water-producing zones, water-receiving zones, zones of vertical flow, borehole depth, and casing integrity in each well. This data and interpretation will be used to determine the location of the well intake for the existing open-hole wells, which will be retrofitted to isolate and monitor water-producing zones and prevent further cross-contamination within each open borehole, and identify wells that may need rehabilitation or replacement. Caliper and video logs were used to locate fractures, inflections on fluid-temperature and fluidresistivity logs indicated possible fluid-bearing fractures, and flowmeter measurements verified these locations. Single-point-resistance and natural-gamma logs provided information on stratigraphy. After interpretation of geophysical logs, video logs, and driller?s notes, all wells will be constructed so that water-level fluctuations can be monitored and discrete water samples collected from shallow, intermediate, and deep water-bearing zones in each well. Geophysical logs were run on seven bedrock and two deep bedrock wells. Gamma logs were run on 10 bedrock wells. Twenty-two wells were inspected visually with the borehole video camera for casing integrity.

  10. Detection of environmentally persistent free radicals at a superfund wood treating site.

    Science.gov (United States)

    dela Cruz, Albert Leo N; Gehling, William; Lomnicki, Slawomir; Cook, Robert; Dellinger, Barry

    2011-08-01

    Environmentally persistent free radicals (EPFRs) have previously been observed in association with combustion-generated particles and airborne PM(2.5) (particulate matter, d 2.5um). The purpose of this study was to determine if similar radicals were present in soils and sediments at Superfund sites. The site was a former wood treating facility containing pentachlorophenol (PCP) as a major contaminant. Both contaminated and noncontaminated (just outside the contaminated area) soil samples were collected. The samples were subjected to the conventional humic substances (HS) extraction procedure. Electron paramagnetic resonance (EPR) spectroscopy was used to measure the EPFR concentrations and determine their structure for each sample fraction. Analyses revealed a ∼30× higher EPFR concentration in the PCP contaminated soils (20.2 × 10(17) spins/g) than in the noncontaminated soil (0.7 × 10(17) spins/g). Almost 90% of the EPFR signal originated from the minerals/clays/humins fraction. GC-MS analyses revealed ∼6500 ppm of PCP in the contaminated soil samples and none detected in the background samples. Inductively coupled plasma-atomic emission spectrophotometry (ICP-AES) analyses revealed ∼7× higher concentrations of redox-active transition metals, in the contaminated soils than the noncontaminated soil. Vapor phase and liquid phase dosing of the clays/minerals/humins fraction of the soil with PCP resulted in an EPR signal identical to that observed in the contaminated soil, strongly suggesting the observed EPFR is pentachlorophenoxyl radical. Chemisorption and electron transfer from PCP to transition metals and other electron sinks in the soil are proposed to be responsible for EPFR formation.

  11. Geochemical Characteristics of TP3 Mine Wastes at the Elizabeth Copper Mine Superfund Site, Orange County, Vermont

    Science.gov (United States)

    Hammarstrom, Jane M.; Piatak, Nadine M.; Seal, Robert R., II; Briggs, Paul H.; Meier, Allen L.; Muzik, Timothy L.

    2003-01-01

    Remediation of the Elizabeth mine Superfund site in the Vermont copper belt poses challenges for balancing environmental restoration goals with issues of historic preservation while adopting cost-effective strategies for site cleanup and long-term maintenance. The waste-rock pile known as TP3, at the headwaters of Copperas Brook, is especially noteworthy in this regard because it is the worst source of surface- and ground-water contamination identified to date, while also being the area of greatest historical significance. The U.S. Geological Survey (USGS) conducted a study of the historic mine-waste piles known as TP3 at the Elizabeth mine Superfund site near South Strafford, Orange County, VT. TP3 is a 12.3-acre (49,780 m2) subarea of the Elizabeth mine site. It is a focus area for historic preservation because it encompasses an early 19th century copperas works as well as waste from late 19th- and 20th century copper mining (Kierstead, 2001). Surface runoff and seeps from TP3 form the headwaters of Copperas Brook. The stream flows down a valley onto flotation tailings from 20th century copper mining operations and enters the West Branch of the Ompompanoosuc River approximately 1 kilometer downstream from the mine site. Shallow drinking water wells down gradient from TP3 exceed drinking water standards for copper and cadmium (Hathaway and others, 2001). The Elizabeth mine was listed as a Superfund site in 2001, mainly because of impacts of acid-mine drainage on the Ompompanoosuc River.

  12. Superfund and Toxic Release Inventory Sites, Point or polygon geo-location of federally designated superfund sites in Wisconsin. Usually geolocated via on screen digitizing against DOPs (could be geo-located via GPS). Source year of DOPs vary, Published in unknown, 1:4800 (1in=400ft) scale, Wisconsin DNR - Bureau of Remediation and Redevelopment.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Superfund and Toxic Release Inventory Sites dataset, published at 1:4800 (1in=400ft) scale, was produced all or in part from Orthoimagery information as of...

  13. Using a triad approach in the assessment of hazardous waste site leaching from a Superfund site to an adjacent stream

    Energy Technology Data Exchange (ETDEWEB)

    Leppanen, C.J. [Univ. of Maine, Orono, ME (United States). Dept. of Biochemistry, Microbiology, and Molecular Biology; Blanner, P.M.; Allan, R.S.; Maier, K.J. [Univ. of Memphis, TN (United States); Benson, W.H. [Univ. of Mississippi, University, MS (United States)

    1998-10-01

    A triad approach was used in the evaluation of sediment in the Wolf River adjacent to the North Hollywood Dump, a federally listed Superfund site. Chemical analyses were done for 18 organochlorine pesticides, 21 polychlorinated biphenyl (PCB) congeners, and 10 metals. Sediment toxicity was evaluated with freshwater invertebrates. Chironomus tentans and Hyalella azteca. Benthic macroinvertebrate diversity and abundance were assessed with a family-level biotic index. Mean Al, Ba, Cd, Cu, Fe, Ni, Pb, and Zn concentrations were significantly higher in sediments collected in the spring. Both spring and fall sediments exhibited toxicity downstream from, adjacent to, and upstream from the dump, with toxicity significantly higher in fall sediments; however, a consistent trend was not observed. Toxicity was typically greater in the fall, and metal concentrations were typically higher in spring sediments, suggesting that metals were not responsible for the toxicity. Sediment-associated organochlorine pesticide and PCB congener concentrations were all below detectable limits, suggesting that these potential contaminants are not contributing to the observed toxicity. No differences were found in benthic macroinvertebrate community structure, which was composed of predominantly pollution-tolerant families, among seasons or river reaches, which appear to be limited by the physical characteristics of the river. Sediments in urban reaches of the Wolf River appear to be degraded; the North Hollywood Dump cannot be isolated as a source of toxicity in this study. In situ testing, sediment toxicity identification and evaluation testing, acid-volatile sulfide analyses, or artificial substrate work would be appropriate to follow.

  14. EPA Proposes to Remove Most of Fulton, Oswego County, New York Site from Superfund List

    Science.gov (United States)

    (New York, N.Y) After cleaning up more than 10,000 cubic yards of contaminated soil and approximately 9 million gallons of contaminated groundwater, the U.S. Environmental Protection Agency is proposing to remove a portion of the Fulton Terminals Superfund

  15. Superfund and Toxic Release Inventory Sites - MO 2010 Permitted Hazardous Waste Sites - Areas(SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This is a polygon data set depicting locations of facilities' property boundaries. The data set contains sites permitted to treat, store or dispose of hazardous...

  16. EPA Finalizes Plan to Address Contaminated Groundwater at Curtis Specialty Papers Superfund Site in Milford Borough and Alexandria Township, N.J.

    Science.gov (United States)

    (New York, N.Y.) The U.S. Environmental Protection Agency has finalized a plan to clean up contaminated groundwater at the Curtis Specialty Papers Superfund site in Milford Borough and Alexandria Township, New Jersey. The site includes the former Milford P

  17. Analysis of geophysical logs, at North Penn Area 6 Superfund Site, Lansdale, Montgomery County, Pennsylvania

    Science.gov (United States)

    Conger, Randall W.

    1999-01-01

    The U.S. Geological Survey (USGS), as part of technical assistance to the U.S. Environmental Protection Agency (USEPA), collected borehole geophysical log data in 34 industrial, commercial, and public supply wells and 28 monitor wells at the North Penn Area 6 Superfund Site, in Lansdale, Pa., from August 22, 1995, through August 29, 1997. The wells range in depth from 50 to 1,027 feet below land surface and are drilled in Triassic-age shales and siltstones of the Brunswick Group and Lockatong Formation. The geophysical log data were collected to help describe the hydrogeologic framework in the area and to provide guidance in the reconstruction of the 28 monitor wells drilled during summer 1997. At the time of logging, all wells had open-hole construction. The geophysical logs, caliper, fluid-resistivity, and fluid-temperature, and borehole video logs were used to determine the vertical distribution of water-bearing fractures. Heatpulse-flowmeter measurements were used to determine vertical borehole flow under pumping and nonpumping conditions. The most productive fractures generally could be determined from heatpulse-flowmeter measurements under pumping conditions. Vertical borehole flow was measured under nonpumping conditions in most wells that had more than one water-bearing fracture. Upward flow was measured in 35 wells and probably is a result of natural head differences between fractures in the local ground-water-flow system. Downward flow was measured in 11 wells and commonly indicated differences in hydraulic heads of the fractures caused by nearby pumping. Both upward and downward flow was measured in three wells. No flow was detected in eight wells. Natural-gamma-ray logs were used to estimate the attitude of bedding. Thin shale marker beds, shown as spikes of elevated radioactivity in the natural-gamma logs of some wells throughout the area, enable the determination of bedding-plane orientation from three-point correlations. Generally, the marker beds in

  18. Superfund Query

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Superfund Query allows users to retrieve data from the Comprehensive Environmental Response, Compensation, and Liability Information System (CERCLIS) database.

  19. Feasibility Study of Economics and Performance of Solar Photovoltaics at the Stringfellow Superfund Site in Riverside, California

    Energy Technology Data Exchange (ETDEWEB)

    Mosey, G.; Van Geet, O.

    2010-12-01

    This report presents the results of an assessment of the technical and economic feasibility of deploying a photovoltaics (PV) system on the Stringfellow Superfund Site in Riverside, California. The site was assessed for possible PV installations. The cost, performance, and site impacts of different PV options were estimated. The economics of the potential systems were analyzed using an electric rate of $0.13/kWh and incentives offered by Southern California Edison under the California Solar Initiative. According to the assessment, a government-owned, ground-mounted PV system represents a technically and economically feasible option. The report recommends financing options that could assist in the implementation of such a system.

  20. In situ field screening for polynuclear aromatic hydrocarbons with a portable spectrofluorometer at a Superfund site near Jackson, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Amick, E.N.; Pollard, J.E. [Lockheed Environmental Systems and Technologies Co., Las Vegas, NV (United States); Engelmann, W.H. [Environmental Protection Agency, Las Vegas, NV (United States). Environmental Monitoring Systems Lab.; Vo-Dinh, T. [Oak Ridge National Lab., TN (United States). Advanced Monitoring Development Group

    1994-12-31

    The US Environmental Protection Agency`s (EPA) Environmental Monitoring Systems Laboratory in Las Vegas, Nevada (EMSL-LV) is currently evaluating the use of scanning ultraviolet-visible (UV-vis) fluorescence as a field screening technology. A prototype field-portable spectrofluorometer capable of excitation, emission, and synchronous scans has been developed and was field tested at the American Creosote Works Superfund site. The UV-vis fluorescence spectra of various polynuclear aromatic hydrocarbons (PAHs) were clearly seen in the synchronous spectra of soil samples extracted on site. Split soil samples were analyzed by gas chromatography/mass spectroscopy and by immunoassay methods. Although a comparison of results with these other methods has not been completed, the synchronous fluorescence method shows promise in that analytical results have the potential to provide compound- or class-selective results and can be immediately available on-site at a reasonable cost.

  1. Geophysical logging and thermal imaging near the Hemphill Road TCE National Priorities List Superfund site near Gastonia, North Carolina

    Science.gov (United States)

    Antolino, Dominick J.; Chapman, Melinda J.

    2017-03-27

    Borehole geophysical logs and thermal imaging data were collected by the U.S. Geological Survey near the Hemphill Road TCE (trichloroethylene) National Priorities List Superfund site near Gastonia, North Carolina, during August 2014 through February 2015. In an effort to assist the U.S. Environmental Protection Agency in the development of a conceptual groundwater model for the assessment of current contaminant distribution and future migration of contaminants, surface geological mapping and borehole geophysical log and thermal imaging data collection, which included the delineation of more than 600 subsurface features (primarily fracture orientations), was completed in five open borehole wells and two private supply bedrock wells. In addition, areas of possible groundwater discharge within a nearby creek downgradient of the study site were determined based on temperature differences between the stream and bank seepage using thermal imagery.

  2. Getting the Biggest Bang for Your Buck: Wildlife Monitoring on Shrublands of the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Derek B. [NSTec; Greger, Paul D. [NSTec

    2011-08-30

    The Nevada Test Site (NTS) covers 3,561 km2 and extends over portions of both the Mojave and Great Basin Deserts. The resulting diverse and complex flora and fauna exhibit elements of both deserts. There are 20 vegetation associations, composed primarily of shrubs, nested within 10 vegetation alliances. Of the more than 1,200 invertebrate and 339 vertebrate species found in these shrubland habitats, 267 are considered sensitive or protected/regulated by federal or state laws. Wildlife and wildlife habitat monitoring ensures NTS activities comply with all federal and state laws enacted for the protection of these valuable biological resources and provides ecological information that can be used to predict and evaluate the potential impacts of proposed projects and current activities on these resources. This paper describes the monitoring approach used at this large site. Monitoring strategies include conducting preactivity surveys, proactively monitoring sensitive species, monitoring long-term population trends, and collaborating with other agencies and biologists. Ways to make monitoring more efficient and examples of successful monitoring and collaborations are discussed.

  3. Calculating the Diffusive Flux of Persistent Organic Pollutants between Sediments and the Water Column on the Palos Verdes Shelf Superfund Site using Polymeric Passive Samplers

    Science.gov (United States)

    Passive samplers were used to determine water concentrations of persistent organic pollutants (POPs) in the surface sediments and near-bottom water of a marine Superfund site on the Palos Verdes Shelf, California, USA. Measured concentrations in the porewater and water column at...

  4. Passive Sampling to Measure Baseline Dissolved Persistent Organic Pollutant Concentrations in the Water Column of the Palos Verdes Shelf Superfund Site

    Science.gov (United States)

    Passive sampling was used to deduce water concentrations of persistent organic pollutants (POPs) in the vicinity of a marine Superfund site on the Palos Verdes Shelf, California, USA. Pre-calibrated solid phase microextraction (SPME) fibers and polyethylene (PE) strips that were...

  5. DOJ News Release: New York Man Ordered to Pay Over $400,000 in Restitution and Fines for Role in Kickback Scheme at New Jersey Superfund Sites

    Science.gov (United States)

    WASHINGTON, D.C. – An Amherst, New York, man was ordered to pay over $400,000 in restitution and fines and placed on five years’ probation for his role in a kickback scheme at the Federal Creosote and Diamond Alkali Superfund sites in New Jersey.

  6. Occurences and Fate of DDT Principal Isomers/Metabolites, DDA, and o,p'-DDD Enantiomers in Fish, Sediment and Water at a DDT-Impacted Superfund Site

    Science.gov (United States)

    In the 1950s and 60s, discharges from a DDT manufacturing plant contaminated a tributary system of the Tennessee River near Huntsville, Alabama, USA. Regulatory action resulted in declaring the area a Superfund site which required remediation and extensive monitoring. Monitoring ...

  7. Ethanol-Fed Or Solid-Phase Organic Sulfate Reducing Bioreactors For The National Tunnel Drainage, Clear Creek/Central City Superfund Site (Presentation)

    Science.gov (United States)

    The U.S. Environmental Protection Agency (EPA) is planning to treat mining influenced water (MIW) from the National Tunnel Adit that discharges to North Clear Creek near the City of Blackhawk, Colorado. North Clear Creek is part of the Clear Creek/Central City Superfund Site, an...

  8. Ethanol-Fed Or Solid-Phase Organic Sulfate Reducing Bioreactors For The National Tunnel Drainage, Clear Creek/Central City Superfund Site

    Science.gov (United States)

    The U.S. Environmental Protection Agency (EPA) is planning to treat mining influenced water (MIW) from the National Tunnel Adit that discharges to North Clear Creek near the City of Blackhawk, Colorado. North Clear Creek is part of the Clear Creek/Central City Superfund Site, an...

  9. COMPARISON OF GEOPROBE PRT AND AMS GVP SOIL-GAS SAMPLING SYSTEMS WITH DEDICATED VAPOR PROBES IN SANDY SOILS AT THE RAYMARK SUPERFUND SITE

    Science.gov (United States)

    A study was conducted near the Raymark Superfund Site in Stratford, Connecticut to compare results of soil-gas sampling using dedicated vapor probes, a truck-mounted direct-push technique - the Geoprobe Post-Run-Tubing (PRT) system, and a hand-held rotary hammer technique - the A...

  10. Post-Remediation Biomonitoring of Pesticides in Marine Waters Near the United Heckathorn Superfund Site, Richmond, California

    Energy Technology Data Exchange (ETDEWEB)

    LD Antrim; NP Kohn

    2000-09-05

    This report, PNNL-11911 Rev. 1, was published in July 2000 and replaces PNNL-11911, which was published in September 1998. The revision corrects tissue concentration units that were reported as dry weight but were actually wet weight, and updates conclusions based on the correct reporting units. Marine sediment remediation at the United Heckathorn Superfund Site was completed in April 1997. Water and mussel tissues were sampled in January 1998 from four stations near Lauritzen Canal in Richmond, California, for the first post-remediation monitoring of marine areas near the United Heckathorn Site. Dieldrin and DDT were analyzed in water samples, tissue samples from resident mussels, and tissue samples from transplanted mussels deployed for 4 months. Concentrations of dieldrin and total DDT in water and total DDT in tissue were compared to pre-remediation data available from the California State Mussel Watch program (tissues) and the Ecological Risk Assessment for the United Heckathorn Superfund Site (tissues and water). Chlorinated pesticide concentrations in water samples were similar to pre-remediation levels and did not meet remediation goals. Mean dieldrin concentrations in water ranged from 0.65 ng/L to 18.1 ng/L and were higher than the remediation goal (0.14 ng/L) at all stations. Mean total DDT concentrations in water ranged from 0.65 ng/L to 103 ng/L and exceeded the remediation goal of 0.59 ng/L. The highest concentrations of both pesticides were found in Lauritzen Canal, and the lowest levels were from the Richmond Inner Harbor Channel water. Unusual amounts of detritus in the water column at the time of sampling, particularly in Lauritzen Canal, could have contributed to the elevated pesticide concentrations and poor analytical precision.

  11. Aquatic assessment of the Pike Hill Copper Mine Superfund site, Corinth, Vermont

    Science.gov (United States)

    Piatak, Nadine M.; Argue, Denise M.; Seal, Robert R.; Kiah, Richard G.; Besser, John M.; Coles, James F.; Hammarstrom, Jane M.; Levitan, Denise M.; Deacon, Jeffrey R.; Ingersoll, Christopher G.

    2013-01-01

    The Pike Hill Copper Mine Superfund site in Corinth, Orange County, Vermont, includes the Eureka, Union, and Smith mines along with areas of downstream aquatic ecosystem impairment. The site was placed on the U.S. Environmental Protection Agency (USEPA) National Priorities List in 2004. The mines, which operated from about 1847 to 1919, contain underground workings, foundations from historical structures, several waste-rock piles, and some flotation tailings. The mine site is drained to the northeast by Pike Hill Brook, which includes several wetland areas, and to the southeast by an unnamed tributary that flows to the south and enters Cookville Brook. Both brooks eventually drain into the Waits River, which flows into the Connecticut River. The aquatic ecosystem at the site was assessed using a variety of approaches that investigated surface-water quality, sediment quality, and various ecological indicators of stream-ecosystem health. The degradation of surface-water quality is caused by elevated concentrations of copper, and to a lesser extent cadmium, with localized effects caused by aluminum, iron, and zinc. Copper concentrations in surface waters reached or exceeded the USEPA national recommended chronic water-quality criteria for the protection of aquatic life in all of the Pike Hill Brook sampling locations except for the location farthest downstream, in half of the locations sampled in the tributary to Cookville Brook, and in about half of the locations in one wetland area located in Pike Hill Brook. Most of these same locations also contained concentrations of cadmium that exceeded the chronic water-quality criteria. In contrast, surface waters at background sampling locations were below these criteria for copper and cadmium. Comparison of hardness-based and Biotic Ligand Model (BLM)-based criteria for copper yields similar results with respect to the extent or number of stations impaired for surface waters in the affected area. However, the BLM

  12. Geophysical logging and geologic mapping data in the vicinity of the GMH Electronics Superfund site near Roxboro, North Carolina

    Science.gov (United States)

    Chapman, Melinda J.; Clark, Timothy W.; Williams, John H.

    2013-01-01

    Geologic mapping, the collection of borehole geophysical logs and images, and passive diffusion bag sampling were conducted by the U.S. Geological Survey North Carolina Water Science Center in the vicinity of the GMH Electronics Superfund site near Roxboro, North Carolina, during March through October 2011. The study purpose was to assist the U.S. Environmental Protection Agency in the development of a conceptual groundwater model for the assessment of current contaminant distribution and future migration of contaminants. Data compilation efforts included geologic mapping of more than 250 features, including rock type and secondary joints, delineation of more than 1,300 subsurface features (primarily fracture orientations) in 15 open borehole wells, and the collection of passive diffusion-bag samples from 42 fracture zones at various depths in the 15 wells.

  13. Geophysical logging and thermal imaging at the Hemphill Road TCE NPL Superfund site near Gastonia, North Carolina

    Science.gov (United States)

    Antolino, Dominick J.; Chapman, Melinda J.

    2017-01-01

    The collection of borehole geophysical logs and thermal imaging data was conducted by the U.S. Geological Survey South Atlantic Water Science Center in the vicinity of the Hemphill Road TCE National Priorities List Superfund site near Gastonia, North Carolina, during August 2014 through February 2015. In an effort to assist the U.S. Environmental Protection Agency in the development of a conceptual groundwater model for the assessment of current contaminant distribution and future migration of contaminants, surface geological mapping and borehole geophysical log and image data collection, which included the delineation of more than 600 subsurface features (primarily fracture orientations) was conducted in 5 open borehole wells and 2 private supply bedrock wells. In addition, areas of potential groundwater discharge within a down-gradient, nearby creek were determined using thermal imagery to calculate temperature differences between the stream and bank seepage.

  14. Investigation of total and hexavalent chromium in filtered and unfiltered groundwater samples at the Tucson International Airport Superfund Site

    Science.gov (United States)

    Tillman, Fred; McCleskey, R. Blaine; Hermosillo, Edyth

    2016-01-01

    Potential health effects from hexavalent chromium in groundwater have recently become a concern to regulators at the Tucson International Airport Area Superfund site. In 2016, the U.S. Geological Survey sampled 46 wells in the area to characterize the nature and extent of chromium in groundwater, to understand what proportion of total chromium is in the hexavalent state, and to determine if substantial differences are present between filtered and unfiltered chromium concentrations. Results indicate detectable chromium concentrations in all wells, over 75 % of total chromium is in the hexavalent state in a majority of wells, and filtered and unfiltered results differ substantially in only a few high-turbidity total chromium samples.

  15. Influence of a chlor-alkali superfund site on mercury bioaccumulation in periphyton and low-trophic level fauna

    Science.gov (United States)

    Buckman, Kate L.; Marvin-DiPasquale, Mark C.; Taylor, Vivien F.; Chalmers, Ann T.; Broadley, Hannah J.; Agee, Jennifer L.; Jackson, Brian P.; Chen, Celia Y.

    2015-01-01

    In Berlin, New Hampshire, USA, the Androscoggin River flows adjacent to a former chlor-alkali facility that is a US Environmental Protection Agency Superfund site and source of mercury (Hg) to the river. The present study was conducted to determine the fate and bioaccumulation of methylmercury (MeHg) to lower trophic-level taxa in the river. Surface sediment directly adjacent to the source showed significantly elevated MeHg (10–40× increase, mean ± standard deviation [SD]: 20.1 ± 24.8 ng g–1 dry wt) and total mercury (THg; 10–30× increase, mean ± SD: 2045 ± 2669 ng g–1 dry wt) compared with all other reaches, with sediment THg and MeHg from downstream reaches elevated (3–7× on average) relative to the reference (THg mean ± SD: 33.5 ± 9.33 ng g–1 dry wt; MeHg mean ± SD: 0.52 ± 0.21 ng g–1 dry wt). Water column THg concentrations adjacent to the point source for both particulate (0.23 ng L–1) and dissolved (0.76 ng L–1) fractions were 5-fold higher than at the reference sites, and 2-fold to 5-fold higher than downstream. Methylmercury production potential of periphyton material was highest (2–9 ng g–1 d–1 dry wt) adjacent to the Superfund site; other reaches were close to or below reporting limits (0. 1 ng g–1 d–1 dry wt). Total Hg and MeHg bioaccumulation in fauna was variable across sites and taxa, with no clear spatial patterns downstream of the contamination source. Crayfish, mayflies, and shiners showed a weak positive relationship with porewater MeHg concentration.

  16. Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005

    Science.gov (United States)

    Kiah, Richard G.; Deacon, Jeffrey R.; Piatak, Nadine M.; Seal, Robert R.; Coles, James F.; Hammarstrom, Jane M.

    2007-01-01

    The hydrology and quality of surface water in and around the Pike Hill Brook watershed, in Corinth, Vermont, was studied from October 2004 to December 2005 by the U.S. Geological Survey in cooperation with the U.S. Environmental Protection Agency (USEPA). Pike Hill was mined intermittently for copper from 1847 to 1919 and the site is known to be contributing trace elements and acidity to Pike Hill Brook and an unnamed tributary to Cookville Brook. The site has been listed as a Superfund site since 2004. Streamflow, specific conductance, pH, and water temperature were measured continuously and monthly at three sites on Pike Hill Brook to determine the variation in these parameters over an annual cycle. Synoptic water-quality sampling was done at 10 stream sites in October 2004, April 2005, and June 2005 and at 13 stream sites in August 2005 to characterize the quality of surface water in the watershed on a seasonal and spatial basis, as well as to assess the effects of wetlands on water quality. Samples for analysis of benthic macroinvertebrate populations were collected at 11 stream sites in August 2005. Water samples were analyzed for 5 major ions and 32 trace elements. Concentrations of trace elements at sites in the Pike Hill Brook watershed exceeded USEPA National Recommended Water Quality Criteria acute and chronic toxicity standards for aluminum, iron, cadmium, copper, and zinc. Concentrations of copper exceeded the chronic criteria in an unnamed tributary to Cookville Brook in one sample. Concentrations of sulfate, calcium, aluminum, iron, cadmium, copper, and zinc decreased with distance from a site directly downstream from the mine (site 1), as a result of dilution and through sorption and precipitation of the trace elements. Maximum concentrations of aluminum, iron, cadmium, copper, and zinc were observed during spring snowmelt. Concentrations of sulfate, calcium, cadmium, copper, and zinc, and instantaneous loads of calcium and aluminum were

  17. Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005

    Science.gov (United States)

    Kiah, Richard G.; Deacon, Jeffrey R.; Piatak, Nadine M.; Seal, Robert R., II; Coles, James F.; Hammarstrom, Jane M.

    2007-01-01

    The hydrology and quality of surface water in and around the Pike Hill Brook watershed, in Corinth, Vermont, was studied from October 2004 to December 2005 by the U.S. Geological Survey in cooperation with the U.S. Environmental Protection Agency (USEPA). Pike Hill was mined intermittently for copper from 1847 to 1919 and the site is known to be contributing trace elements and acidity to Pike Hill Brook and an unnamed tributary to Cookville Brook. The site has been listed as a Superfund site since 2004. Streamflow, specific conductance, pH, and water temperature were measured continuously and monthly at three sites on Pike Hill Brook to determine the variation in these parameters over an annual cycle. Synoptic water-quality sampling was done at 10 stream sites in October 2004, April 2005, and June 2005 and at 13 stream sites in August 2005 to characterize the quality of surface water in the watershed on a seasonal and spatial basis, as well as to assess the effects of wetlands on water quality. Samples for analysis of benthic macroinvertebrate populations were collected at 11 stream sites in August 2005. Water samples were analyzed for 5 major ions and 32 trace elements. Concentrations of trace elements at sites in the Pike Hill Brook watershed exceeded USEPA National Recommended Water Quality Criteria acute and chronic toxicity standards for aluminum, iron, cadmium, copper, and zinc. Concentrations of copper exceeded the chronic criteria in an unnamed tributary to Cookville Brook in one sample. Concentrations of sulfate, calcium, aluminum, iron, cadmium, copper, and zinc decreased with distance from a site directly downstream from the mine (site 1), as a result of dilution and through sorption and precipitation of the trace elements. Maximum concentrations of aluminum, iron, cadmium, copper, and zinc were observed during spring snowmelt. Concentrations of sulfate, calcium, cadmium, copper, and zinc, and instantaneous loads of calcium and aluminum were

  18. Evaluation of borehole geophysical and video logs, at Butz Landfill Superfund Site, Jackson Township, Monroe County, Pennsylvania

    Science.gov (United States)

    Low, D.J.; Conger, R.W.

    2001-01-01

    Between February 1996 and November 2000, geophysical logging was conducted in 27 open borehole wells in and adjacent to the Butz Landfill Superfund Site, Jackson Township, Monroe County, Pa., to determine casing depth and depths of water-producing zones, water-receiving zones, and zones of vertical borehole flow. The wells range in depth from 57 to 319 feet below land surface. The geophysical logging determined the placement of well screens and packers, which allow monitoring and sampling of water-bearing zones in the fractured bedrock so that the horizontal and vertical distribution of contaminated ground water migrating from known sources could be determined. Geophysical logging included collection of caliper, natural-gamma, single-point-resistance, fluid-resistivity, fluid-temperature, and video logs. Caliper and video logs were used to locate fractures, joints, and weathered zones. Inflections on single-point-resistance, fluid-temperature, and fluid-resistivity logs indicated possible water-bearing fractures, and heatpulse-flowmeter measurements verified these locations. Natural-gamma logs provided information on stratigraphy.

  19. The electro-thermal dynamic stripping process for the remediation of a creosote-contaminated superfund site

    Energy Technology Data Exchange (ETDEWEB)

    Northington, C.D. [WRS Infrastructure and Environment, Tampa, FL (United States); McGee, B.C.W. [McMillan-McGee Corp., Calgary, AB (Canada)

    2005-07-01

    Pump-and-treat is a conventional soil and groundwater contaminant removal method that depends on factors such as the chemical nature of the contaminant, subsurface heterogeneity, sorption of contaminants to subsurface materials, difficulties in characterizing the subsurface, and system design. The cleanup of dense non-aqueous phase liquids (DNAPLs) is further complicated by the uncertain contaminant fate due to the tendency of DNAPLs to migrate downward, where they become difficult to locate and where they become immobile residual globules and a long-term source of ground water contamination. This paper presents the results of a pilot scale study in which an in-situ thermal decontamination technology was tested. The technology known as the Electro-Thermal Dynamic Stripping Process{sup TM} (ET-DS), was developed for a creosote-contaminated Superfund site to show the effectiveness of full-scale implementation of this method over the currently used pump-and- treat system to address contamination in the source zone. The pilot study follows similar methods used by reservoir engineers in the evaluation of thermal recovery methods for the recovery of bitumen and heavy oil. ET-DS was field test in the oil sands in order to use some operating data from the pilot to design oil sand specific ET-DS.

  20. SUPERFUND CLEANUPS AND INFANT HEALTH

    Science.gov (United States)

    Currie, Janet; Greenstone, Michael; Moretti, Enrico

    2013-01-01

    We are the first to examine the effect of Superfund cleanups on infant health rather than focusing on proximity to a site. We study singleton births to mothers residing within 5km of a Superfund site between 1989–2003 in five large states. Our “difference in differences” approach compares birth outcomes before and after a site clean-up for mothers who live within 2,000 meters of the site and those who live between 2,000– 5,000 meters of a site. We find that proximity to a Superfund site before cleanup is associated with a 20 to 25% increase in the risk of congenital anomalies. PMID:25152535

  1. Relating Magnetic Parameters to Heavy Metal Concentrations and Environmental Factors at Formosa Mine Superfund Site, Douglas County, OR

    Science.gov (United States)

    Upton, T. L.

    2016-12-01

    Advances in the field of environmental magnetism have led to exciting new applications for this field. Magnetic minerals are ubiquitous in the environment and tend to have an affinity for heavy metals. Hence, it has been demonstrated that magnetic properties are often significantly related to concentrations of heavy metals and other pollutants. As a result, magnetic techniques have been used as proxy for determining hot spots of several types of pollution produced from a diversity of anthropogenic sources. Magnetic measurements are non-destructive and relatively inexpensive compared to geochemical analyses. The utility of environmental magnetic methods varies widely depending on biological, chemical and physical processes that create and transform soils and sediments. Applications in the direction of mapping heavy metals have been studied and shown to be quite useful in countries such as China and India but to date, little research has been done in the US. As such, there is need to expand the scope of research to a wider range of soil types and land uses, especially within the US. This study investigates the application of environmental magnetic techniques to mapping of heavy metal concentrations at the Formosa Mine Superfund Site, an abandoned mine about 25 miles southwest of Roseburg, OR. The soils and sediment at this site are derived from pyrite-rich bedrock which is weak in terms of magnetic susceptibility. Using hotspot analysis, correlation and cluster analyses, interactions between metals and magnetic parameters are investigated in relation to environmental factors such as proximity to seeps and adits. Preliminary results suggest significant correlation of magnetic susceptibility with certain heavy metals, signifying that magnetic methods may be useful in mapping heavy metal hotspots at this site. Further analysis examines the relation of various land use differences in magnetic signatures obtained throughout the Cow Creek watershed.

  2. Description of borehole geophysical and geologist logs, Berks Sand Pit Superfund Site, Longswamp Township, Berks County, Pennsylvania

    Science.gov (United States)

    Low, Dennis J.; Conger, Randall W.

    2003-01-01

    Between October 2002 and January 2003, geophysical logging was conducted in six boreholes at the Berks Sand Pit Superfund Site, Longswamp Township, Berks County, Pa., to determine (1) the waterproducing zones, water-receiving zones, zones of vertical borehole flow, orientation of fractures, and borehole and casing depth; and (2) the hydraulic interconnection between the six boreholes and the site extraction well. The boreholes range in depth from 61 to 270 feet. Geophysical logging included collection of caliper, natural-gamma, single-point-resistance, fluid-temperature, fluid-flow, and acoustic-televiewer logs. Caliper and acoustic-televiewer logs were used to locate fractures, joints, and weathered zones. Inflections on fluid-temperature and single-point-resistance logs indicated possible water-bearing fractures, and flowmeter measurements verified these locations. Single-point-resistance, natural-gamma, and geologist logs provided information on stratigraphy. Flowmeter measurements were conducted while the site extraction well was pumping and when it was inactive to determine the hydraulic connections between the extraction well and the boreholes. Borehole geophysical logging and heatpulse flowmetering indicate active flow in the boreholes. Two of the boreholes are in ground-water discharge areas, two boreholes are in ground-water recharge areas, and one borehole is in an intermediate regime. Flow was not determined in one borehole. Heatpulse flowmetering, in conjunction with the geologist logs, indicates highly weathered zones in the granitic gneiss can be permeable and effective transmitters of water, confirming the presence of a two-tiered ground-water-flow system. The effort to determine a hydraulic connection between the site extraction well and six logged boreholes was not conclusive. Three boreholes showed decreases in depth to water after pumping of the site extraction well; in two boreholes, the depth to water increased. One borehole was cased its

  3. Pilot demonstration for containment using in situ soil mixing techniques at a chemical disposal superfund site

    Energy Technology Data Exchange (ETDEWEB)

    Zarlinski, S.J.; Kingham, N.W.; Semenak, R. [Kiber Environmental Services, Inc., Atlanta, GA (United States)

    1997-12-31

    Kiber Environmental Services, Inc. (Kiber), under contract to McLaren-Hart Corporation and the site PRP group, performed technical oversight and on-site sampling and analyses at the confidential site located in Texas. The site consists of 15,000 cubic meters (20,000 cubic yards) of contaminated materials that were to be solidified on-site. The contaminants included heavy metals, PAHs, oil and grease, and volatile organics. Groundwater is less than 1 meter from the surface. Kiber was retained after several unsuccessful efforts to find on-site containment methods that effectively solidified the waste pits while achieving the performance goals. The PRP group then contracted with Kiber to perform the treatability and pilot oversight studies. The full-scale pilot demonstration was performed by Geo-Con. Pilot-scale treatment was performed to evaluate the effectiveness of in situ solidification treatment at achieving the site specific performance criteria, including an unconfined compressive strength of greater than 170 kPa (25 psi) and a permeability of less than 1x10{sup -6} cm/sec. Technical oversight and on-site sampling and analysis were provided to evaluate pilot-scale application of the selected technology and verify treatment effectiveness. The project was divided into several subtasks. First, laboratory treatability testing was conducted to verify that performance specifications were achievable using the proposed reagent formulations. Next, a pilot demonstration was performed by Geo-Con using a Manotowoc 4000 crane equipped with a 1.5-meter diameter auger to evaluate shallow soil mixing. The final task included a comparative study between the performance of test specimens collected using wet sampling techniques versus in situ post-treatment coring.

  4. Environmental Factor{trademark} system: Superfund site information from five EPA databases

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Environmental Factor puts today`s technology to work to provide a better, more cost-efficient and time-saving way to access EPA information on hazardous waste sites. Environmental consultants, insurers, and reinsurers, corporate risk assessors and companies actively involved in the generation, transport, storage or cleanup of hazardous waste materials can use its user-friendly information retrieval system to gain rapid access to vital information in immediately-usable form. Search, retrieve, and export information in real time. No more waiting for the mail or overnight delivery services to deliver hard copies of voluminous listings and individual site reports. More than 200,000 pages of EPA hazardous waste site information are contained in 5 related databases: (1) Site data from the National Priority List (NPL) and CERCLIS databases, Potentially Responsible Parties (PRP) and Records of Decision (RODs) summaries; (2) Complete PRP information; (3) EPA Records of Decision (Full Text); (4) entire Civil Enforcement Docket; and (5) Glossary of EPA terms, abbreviations and acronyms. Environmental Factor`s powerful database management engine gives even the most inexperienced computer user extensive search capabilities, including wildcard, phonetic and direct cross reference searches across multiple databases.

  5. Passive Treatment And Monitoring At The Standard Mine Superfund Site, Crested Butte, CO (Presentation)

    Science.gov (United States)

    At the 2008 ASMR conference, data from the initial two months of operation of a U.S. EPA pilot biochemical reactor (BCR) was reported. The BCR was designed and constructed in August, 2007 to treat mining influenced water (MIW) emanating from an adit at a remote site in southern ...

  6. Passive Treatment And Monitoring At The Standard Mine Superfund Site, Crested Butte, CO

    Science.gov (United States)

    At the 2008 ASMR conference, data from the initial two months of operation of a U.S. EPA pilot biochemical reactor (BCR) was reported. The BCR was designed and constructed in August, 2007 to treat mining influenced water (MIW) emanating from an adit at a remote site in southern ...

  7. CHARACTERIZATION AND FATE OF PAH-CONTAMINATED SEDIMENTS AT THE WYCKOFF/EAGLE HARBOR SUPERFUND SITE

    Science.gov (United States)

    Eagle Harbor is a shallow marine embayment of Bainbridge Island, WA and formerly the site of the Wyckoff wood-treatment facility. The facility became operational in the early 1900s and used large quantities of creosote in its wood-treating processes. Creosote percolated through t...

  8. Cyclodiene insecticide, DDE, DDT, arsenic, and mercury contamination of big brown bats (Eptesicus fuscus) foraging at a Colorado Superfund site

    Science.gov (United States)

    O'Shea, T.J.; Everette, A.L.; Ellison, L.E.

    2001-01-01

    Rocky Mountain Arsenal (RMA) National Wildlife Area, near Denver, Colorado, is a Superfund site contaminated by past military and industrial uses, including pesticide manufacturing. From an ecosystem standpoint, the most critical contaminants at RMA are certain cyclodiene insecticides and metabolites, p,p???-DDE, p,p???-DDT, arsenic, and mercury. Bats are important ecosystem components that can be impacted by persistent contaminants because of their position in the food chain and their potential longevity and thus duration of exposure. Big brown bats (Eptesicus fuscus) were captured (n = 51) while foraging at RMA in the summers of 1997 and 1998 for determination of concentrations of contaminants of concern in carcasses, brains, and stomach contents. Adult females (n = 15) were also tracked by radiotelemetry to determine locations of nearest maternity roosts for sampling of guano for contaminant analysis and inspection for potential contaminant-induced mortality. Bats captured while foraging at RMA had measurable quantities of dieldrin and DDE in masticated insect samples from stomach contents and significantly higher concentrations of dieldrin, DDE, DDT, and mercury (juveniles) in carcasses than big brown bats (n = 26) sampled at a reference area 80 km to the north. Concentrations of dieldrin and DDE in brains of bats captured while foraging at RMA were also greater than in bats from the reference area, but not high enough to suggest mortality. Maximum concentrations of DDE, DDT, and cyclodienes in brains of big brown bats were found in adult males from RMA. Guano from the two closest known roosts had significantly higher concentrations of dieldrin, DDE, and mercury than guano from two roosts at the reference area. Dieldrin concentrations in carcasses of bats from RMA were highest in juveniles, followed by adult males and adult females. DDE concentrations in carcasses were lowest in adult females at both sites and highest in adult males at RMA. No contaminant

  9. Radon in Soil Gas Above Bedrock Fracture Sets at the Shepley’s Hill Superfund Site

    Energy Technology Data Exchange (ETDEWEB)

    J.R. Giles; T.L. McLing; M.V. Carpenter; C.J. Smith; W. Brandon

    2012-12-01

    The Idaho National Laboratory (INL) recently provided technical support for ongoing environmental remediation activities at the Shepley’s Hill remediation site near Devens, MA (Figure 1). The technical support was requested as follow-on work to an initial screening level radiation survey conducted in 2008. The purpose of the original study was to assess the efficacy of the INL-developed Backpack Sodium Iodide System (BaSIS) for detecting elevated areas of natural radioactivity due to the decay of radon-222 gases emanating from the underlying fracture sets. Although the results from the initial study were mixed, the BaSIS radiation surveys did confirm that exposed bedrock outcrops have higher natural radioactivity than the surficial soils, thus a high potential for detecting elevated levels of radon and/or radon daughter products. (INL 2009) The short count times associated with the BaSIS measurements limited the ability of the system to respond to elevated levels of radioactivity from a subsurface source, in this instance radon gas emanating from fracture sets. Thus, it was postulated that a different methodology be employed to directly detect the radon in the soil gases. The CR-39 particle track detectors were investigated through an extensive literature and technology search. The relatively long deployment or “detection” time of several days, as well as the sensitivity of the measurement and robustness of the detectors made the CR-39 technology promising for deployment at the Shepley’s Hill site.

  10. EPA Encourages the Public to Provide Input on Plan to Address Contaminated Groundwater at Curtis Specialty Papers Superfund Site in Milford and Alexandria Township, New Jersey, Public Meeting to Take Place May 28

    Science.gov (United States)

    (New York, N.Y.) The U.S. Environmental Protection Agency has proposed a plan to clean up contaminated groundwater at the Curtis Specialty Papers Superfund site in Milford and Alexandria Township, New Jersey. The site includes the 86-acre historic former M

  11. Selected Water- and Sediment-Quality, Aquatic Biology, and Mine-Waste Data from the Ely Copper Mine Superfund Site, Vershire, VT, 1998-2007

    Science.gov (United States)

    Argue, Denise M.; Kiah, Richard G.; Piatak, Nadine M.; Seal, Robert R., II; Hammarstrom, Jane M.; Hathaway, Edward; Coles, James F.

    2008-01-01

    The data contained in this report are a compilation of selected water- and sediment-quality, aquatic biology, and mine-waste data collected at the Ely Copper Mine Superfund site in Vershire, VT, from August 1998 through May 2007. The Ely Copper Mine Superfund site is in eastern, central Vermont (fig. 1) within the Vermont Copper Belt (Hammarstrom and others, 2001). The Ely Copper Mine site was placed on the U.S. Environmental Protection Agency (USEPA) National Priorities List in 2001. Previous investigations conducted at the site documented that the mine is contributing metals and highly acidic waters to local streams (Hammarstrom and others, 2001; Holmes and others, 2002; Piatak and others, 2003, 2004, and 2006). The U.S. Geological Survey (USGS), in cooperation with the USEPA, compiled selected data from previous investigations into uniform datasets that will be used to help characterize the extent of contamination at the mine. The data may be used to determine the magnitude of biological impacts from the contamination and in the development of remediation activities. This report contains analytical data for samples collected from 98 stream locations, 6 pond locations, 21 surface-water seeps, and 29 mine-waste locations. The 98 stream locations are within 3 streams and their tributaries. Ely Brook flows directly through the Ely Copper Mine then into Schoolhouse Brook (fig. 2), which joins the Ompompanoosuc River (fig. 1). The six pond locations are along Ely Brook Tributary 2 (fig. 2). The surface-water seeps and mine-waste locations are near the headwaters of Ely Brook (fig. 2 and fig. 3). The datasets 'Site_Directory' and 'Coordinates' contain specific information about each of the sample locations including stream name, number of meters from the mouth of stream, geographic coordinates, types of samples collected (matrix of sample), and the figure on which the sample location is depicted. Data have been collected at the Ely Copper Mine Superfund site by the

  12. Superfund Record of Decision (EPA Region 9): Intel Santa Clara III Superfund site, Santa Clara, CA. (First remedial action), September 1990. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1990-09-20

    The Intel (Santa Clara III) site includes a plant that performs quality control testing of chemicals and electrical testing of semiconductors in Santa Clara, Santa Clara County, California. The site is in a predominantly industrial area, and overlies a major ground regional source of ground water, the Santa Clara Valley ground water basin. In 1982, the State conducted a leak detection program, which identified VOC contamination in an onsite shallow aquifer. Possible sources for the contamination may include the accidental dumping of solvents into an acid neutralization tank, accidental spills near an above-ground solvent storage facility, and cleaning of solvent-contaminated pipes during plant construction. It has been determined that no onsite source is presently contributing to ground water contamination. Since 1985, Intel has been pumping and treating ground water using granular activated carbon as an Initial Remedial Measure (IRM). The Record of Decision (ROD) addresses a final solution for restoring ground water to its beneficial use. The primary contaminants of concern affecting the ground water are VOCs including TCE.

  13. Arsenic species in weathering mine tailings and biogenic solids at the Lava Cap Mine Superfund Site, Nevada City, CA

    Directory of Open Access Journals (Sweden)

    Ashley Roger P

    2011-01-01

    Full Text Available Abstract Background A realistic estimation of the health risk of human exposure to solid-phase arsenic (As derived from historic mining operations is a major challenge to redevelopment of California's famed "Mother Lode" region. Arsenic, a known carcinogen, occurs in multiple solid forms that vary in bioaccessibility. X-ray absorption fine-structure spectroscopy (XAFS was used to identify and quantify the forms of As in mine wastes and biogenic solids at the Lava Cap Mine Superfund (LCMS site, a historic "Mother Lode" gold mine. Principal component analysis (PCA was used to assess variance within water chemistry, solids chemistry, and XAFS spectral datasets. Linear combination, least-squares fits constrained in part by PCA results were then used to quantify arsenic speciation in XAFS spectra of tailings and biogenic solids. Results The highest dissolved arsenic concentrations were found in Lost Lake porewater and in a groundwater-fed pond in the tailings deposition area. Iron, dissolved oxygen, alkalinity, specific conductivity, and As were the major variables in the water chemistry PCA. Arsenic was, on average, 14 times more concentrated in biologically-produced iron (hydroxide than in mine tailings. Phosphorous, manganese, calcium, aluminum, and As were the major variables in the solids chemistry PCA. Linear combination fits to XAFS spectra indicate that arsenopyrite (FeAsS, the dominant form of As in ore material, remains abundant (average: 65% in minimally-weathered ore samples and water-saturated tailings at the bottom of Lost Lake. However, tailings that underwent drying and wetting cycles contain an average of only 30% arsenopyrite. The predominant products of arsenopyrite weathering were identified by XAFS to be As-bearing Fe (hydroxide and arseniosiderite (Ca2Fe(AsO43O3•3H2O. Existence of the former species is not in question, but the presence of the latter species was not confirmed by additional measurements, so its identification is

  14. Geophysical log analysis of selected test and residential wells at the Shenandoah Road National Superfund Site, East Fishkill, Dutchess County, New York

    Science.gov (United States)

    Reynolds, Richard J.; Anderson, J. Alton; Williams, John H.

    2015-01-01

    The U.S. Geological Survey collected and analyzed geophysical logs from 20 test wells and 23 residential wells at the Shenandoah Road National Superfund Site in East Fishkill, New York, from 2006 through 2010 as part of an Interagency Agreement to provide hydrogeologic technical support to the U.S. Environmental Protection Agency, Region 2. The geophysical logs collected include caliper, gamma, acoustic and optical televiewer, deviation, electromagnetic-induction, magnetic-susceptibility, fluid-property, and flow under ambient and pumped conditions. The geophysical logs were analyzed along with single-well aquifer test data and drilling logs to characterize the lithology, fabric, fractures, and flow zones penetrated by the wells. The results of the geophysical log analysis were used as part of the hydrogeologic characterization of the site and in the design of discrete-zone monitoring installations in the test wells and selected residential wells.

  15. Real-Time and Delayed Analysis of Tree and Shrub Cores as Indicators of Subsurface Volatile Organic Compound Contamination, Durham Meadows Superfund Site, Durham, Connecticut, August 29, 2006

    Science.gov (United States)

    Vroblesky, Don A.; Willey, Richard E.; Clifford, Scott; Murphy, James J.

    2008-01-01

    This study examined volatile organic compound concentrations in cores from trees and shrubs for use as indicators of vadose-zone contamination or potential vapor intrusion by volatile organic compounds into buildings at the Durham Meadows Superfund Site, Durham, Connecticut. The study used both (1) real-time tree- and shrub-core analysis, which involved field heating the core samples for 5 to 10 minutes prior to field analysis, and (2) delayed analysis, which involved allowing the gases in the cores to equilibrate with the headspace gas in the sample vials unheated for 1 to 2 days prior to analysis. General correspondence was found between the two approaches, indicating that preheating and field analysis of vegetation cores is a viable approach to real-time monitoring of subsurface volatile organic compounds. In most cases, volatile organic compounds in cores from trees and shrubs at the Merriam Manufacturing Company property showed a general correspondence to the distribution of volatile organic compounds detected in a soil-gas survey, despite the fact that most of the soil-gas survey data in close proximity to the relevant trees were collected about 3 years prior to the tree-core collection. Most of the trees cored at the Durham Meadows Superfund Site, outside of the Merriam Manufacturing Company property, contained no volatile organic compounds and were in areas where indoor air sampling and soil-gas sampling showed little or no volatile organic compound concentrations. An exception was tree DM11, which contained barely detectable concentrations of trichloroethene near a house where previous investigations found low concentrations of trichloroethene (0.13 to 1.2 parts per billion by volume) in indoor air and 7.7 micrograms per liter of trichloroethene in the ground water. The barely detectable concentration of trichloroethene in tree DM11 and the lack of volatile organic compound detection in nearby tree DM10 (adjacent to the well having 7.7 micrograms of

  16. A review of the Texas, USA San Jacinto Superfund site and the deposition of polychlorinated dibenzo-p-dioxins and dibenzofurans in the San Jacinto River and Houston Ship Channel.

    Science.gov (United States)

    Iyer, Rupa; Aggarwal, Juhi; Iken, Brian

    2016-12-01

    The San Jacinto River (SJR) waste pits that lie just under the 1-10 overpass in eastern Harris County east of Houston, Texas, USA, were created in the 1960s as dumping grounds for paper mill waste. The deposition of this waste led to accumulation of highly toxic polychlorinated dibenzo-p-dioxins and dibenzofurans (PCCDDs/PCDFs) over the course of several decades. After abandonment, the waste material eventually became submerged under the waters of the SJR, resulting in widespread environmental contamination that currently constitutes a significant health concern for eastern Harris County communities. The original waste pits were rediscovered in 2005, and the San Jacinto waste site is now a designated EPA superfund site. The objective of this review then is to discuss the history and current state of containment around the San Jacinto waste pits and analyze spatial and temporal trends in the PCDD/PCDF deposition through the SJR system from the data available. We will discuss the current exposure and health risks represented by the Superfund site and the SJR system itself, as well as the discovery of liver, kidney, brain (glioma), and retinoblastoma cancer clusters in eastern Harris County across multiple census tracts that border the Superfund site. We will also cover the two primary management options, containment versus removal of the waste from the Superfund and provide recommendations for increased monitoring of existing concentrations of polychlorinated waste in the SJR and its nearby associated communities.

  17. TREATABILITY STUDY REPORT OF GREEN MOUNTAIN LABORATORIES, INC.'S BIOREMEDIATION PROCESS, TREATMENT OF PCB CONTAMINATED SOILS, AT BEEDE WASTE OIL/CASH ENERGY SUPERFUND SITE, PLAISTOW, NEW HAMPSHIRE

    Science.gov (United States)

    In 1998, Green Mountain Laboratories, Inc. (GML) and the USEPA agreed to carry out a Superfund Innovative Technology Evaluation (SITE) project to evaluate the effectiveness of GML's Bioremediation Process for the treatment of PCB contaminated soils at the Beede Waste Oil/Cash Ene...

  18. Post-Remediation Biomonitoring of Pesticides and Other Contaminants in Marine Waters and Sediment Near the United Heckathorn Superfund Site, Richmond, California

    Energy Technology Data Exchange (ETDEWEB)

    LD Antrim; NP Kohn

    2000-09-06

    This report, PNNL-1 3059 Rev. 1, was published in July 2000 and replaces PNNL-1 3059 which is dated October 1999. The revision corrects tissue concentration units that were reported as dry weight but were actually wet weight, and updates conclusions based on the correct reporting units. Marine sediment remediation at the United Heckathorn Superfund Site was completed in April 1997. Water and mussel tissues were sampled in February 1999 from four stations near Lauritzen Canal in Richmond, California, for Year 2 of post-remediation monitoring of marine areas near the United Heckathom Site. Dieldrin and dichlorodiphenyl trichloroethane (DDT) were analyzed in water samples, tissue samples from resident mussels, and tissue samples from transplanted mussels deployed for 4 months. Concentrations of dieldrin and total DDT in water and total DDT in tissue were compared with Year 1 of post-remediation monitoring, and with preremediation data from the California State Mussel Watch program (tissue s) and the Ecological Risk Assessment for the United Heckathorn Superfund Site (tissues and water). Mussel tissues were also analyzed for polychlorinated biphenyls (PCB), which were detected in sediment samples. Chlorinated pesticide concentrations in water samples were similar to preremediation levels and did not meet remediation goals. Mean dieldrin concentrations in water ranged from 0.62 ng/L to 12.5 ng/L and were higher than the remediation goal (0.14 ng/L) at all stations. Mean total DDT concentrations in water ranged from 14.4 ng/L to 62.3 ng/L and exceeded the remediation goal (0.59 ng/L) at all stations. The highest concentrations of both DDT and dieldrin were found at the Lauritzen Canal/End station. Despite exceedence of the remediation goals, chlorinated pesticide concentrations in Lauritzen Canal water samples were notably lower in 1999 than in 1998. PCBS were not detected in water samples in 1999.

  19. How to Get the Biggest Bang for Your Buck: Wildlife Monitoring on Shrublands of the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Derek Hall, Paul D. Greger

    2008-03-01

    The Nevada Test Site (NTS) covers 1,375 square miles and extends over portions of both the Mojave and Great Basin Deserts. The resulting diverse and complex flora and fauna exhibit elements of both deserts. There are 20 vegetation associations, composed primarily of shrubs, nested within 10 vegetation alliances. Of the more than 1,200 invertebrates and 339 vertebrates found in these shrubland habitats, 267 are considered sensitive or protected/regulated by federal or state laws. Wildlife and wildlife habitat monitoring ensures NTS activities comply with all federal and state laws enacted for the protection of these valuable biological resources. This paper describes the monitoring approach used at this large site. Monitoring techniques include conducting preactivity surveys, repeated sampling of permanent plots, proactively monitoring sensitive species, and collaborating with other agencies and biologists. Ways to make monitoring more efficient and examples of successful monitoring and collaborations are discussed.

  20. Investigations of groundwater system and simulation of regional groundwater flow for North Penn Area 7 Superfund site, Montgomery County, Pennsylvania

    Science.gov (United States)

    Senior, Lisa A.; Goode, Daniel J.

    2013-01-01

    Groundwater in the vicinity of several industrial facilities in Upper Gwynedd Township and vicinity, Montgomery County, in southeast Pennsylvania has been shown to be contaminated with volatile organic compounds (VOCs), the most common of which is the solvent trichloroethylene (TCE). The 2-square-mile area was placed on the National Priorities List as the North Penn Area 7 Superfund site by the U.S. Environmental Protection Agency (USEPA) in 1989. The U.S. Geological Survey (USGS) conducted geophysical logging, aquifer testing, and water-level monitoring, and measured streamflows in and near North Penn Area 7 from fall 2000 through fall 2006 in a technical assistance study for the USEPA to develop an understanding of the hydrogeologic framework in the area as part of the USEPA Remedial Investigation. In addition, the USGS developed a groundwater-flow computer model based on the hydrogeologic framework to simulate regional groundwater flow and to estimate directions of groundwater flow and pathways of groundwater contaminants. The study area is underlain by Triassic- and Jurassic-age sandstones and shales of the Lockatong Formation and Brunswick Group in the Mesozoic Newark Basin. Regionally, these rocks strike northeast and dip to the northwest. The sequence of rocks form a fractured-sedimentary-rock aquifer that acts as a set of confined to partially confined layers of differing permeabilities. Depth to competent bedrock typically is less than 20 ft below land surface. The aquifer layers are recharged locally by precipitation and discharge locally to streams. The general configuration of the potentiometric surface in the aquifer is similar to topography, except in areas affected by pumping. The headwaters of Wissahickon Creek are nearby, and the stream flows southwest, parallel to strike, to bisect North Penn Area 7. Groundwater is pumped in the vicinity of North Penn Area 7 for industrial use, public supply, and residential supply. Results of field investigations

  1. Treatability Study of In Situ Technologies for Remediation of Hexavalent Chromium in Groundwater at the Puchack Well Field Superfund Site, New Jersey

    Energy Technology Data Exchange (ETDEWEB)

    Vermeul, Vince R.; Szecsody, Jim E.; Truex, Michael J.; Burns, Carolyn A.; Girvin, Donald C.; Phillips, Jerry L.; Devary, Brooks J.; Fischer, Ashley E.; Li, Shu-Mei W.

    2006-11-13

    This treatability study was conducted by Pacific Northwest National Laboratory (PNNL), at the request of the U. S. Environmental Protection Agency (EPA) Region 2, to evaluate the feasibility of using in situ treatment technologies for chromate reduction and immobilization at the Puchack Well Field Superfund Site in Pennsauken Township, New Jersey. In addition to in situ reductive treatments, which included the evaluation of both abiotic and biotic reduction of Puchack aquifer sediments, natural attenuation mechanisms were evaluated (i.e., chromate adsorption and reduction). Chromate exhibited typical anionic adsorption behavior, with greater adsorption at lower pH, at lower chromate concentration, and at lower concentrations of other competing anions. In particular, sulfate (at 50 mg/L) suppressed chromate adsorption by up to 50%. Chromate adsorption was not influenced by inorganic colloids.

  2. PCBs and DDE in tree swallow (Tachycineta bicolor) eggs and nestlings from an estuarine PCB superfund site, New Bedford Harbor, MA, U.S.A.

    Science.gov (United States)

    Jayaraman, Saro; Nacci, Diane E.; Champlin, Denise M.; Pruell, Richard J.; Rocha, Kenneth J.; Custer, Christine M.; Custer, Thomas W.; Cantwell, Mark

    2009-01-01

    While breeding tree swallows (Tachycineta bicolor) have been used as biomonitors for freshwater sites, we report the first use of this species to assess contaminant bioaccumulation from estuarine breeding grounds into these aerial insectivores. Eggs and nestlings were collected from nest boxes in a polychlorinated biphenyl (PCB) contaminated estuary, the New Bedford Harbor Superfund site (NBH, Massachusetts, USA), and a reference salt marsh, Fox Hill (FH, Jamestown, Rhode Island, USA). Sediments, eggs, and nestlings were compared on a ng g−1 wet weight basis for total PCBs and DDE (1,1-bis-(4-chlorophenyl)-2,2-dichloroethene), metabolite of DDT (1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane). NBH samples contained high concentrations of PCBs compared to FH for sediment (36,500 and 0.2), eggs (11,200 and 323), and nestlings (16,800 and 26). PCB homologue patterns linked tree swallow contamination to NBH sediment. NBH samples were also contaminated with DDE compared to FH for sediment (207 and 0.9) and nestlings (235 and 30) but not for eggs (526 and 488), suggesting both NBH and nonbreeding ground sources for DDE. The relationships between sediment and tree swallow egg and nestling PCBs were similar to those reported for freshwater sites. Like some highly contaminated freshwater sites, NBH PCB bioaccumulation had little apparent effect on reproductive success.

  3. Identification of potential water-bearing zones by the use of borehole geophysics in the vicinity of Keystone Sanitation Superfund Site, Adams County, Pennsylvania and Carroll County, Maryland

    Science.gov (United States)

    Conger, Randall W.

    1997-01-01

    Between April 23, 1996, and June 21, 1996, the U.S. Environmental Protection Agency contracted Haliburton-NUS, Inc., to drill four clusters of three monitoring wells near the Keystone Sanitation Superfund Site. The purpose of the wells is to allow monitoring and sampling of shallow, intermediate, and deep waterbearing zones for the purpose of determining the horizontal and vertical distribution of any contaminated ground water migrating from the Keystone Site. Twelve monitoring wells, ranging in depth from 50 to 397.9 feet below land surface, were drilled in the vicinity of the Keystone Site. The U.S. Geological Survey conducted borehole-geophysical logging and determined, with geophysical logs and other available data, the ideal intervals to be screened in each well. Geophysical logs were run on four intermediate and four deep wells, and a caliper log only was run on shallow well CL-AD-173 (HN-1S). Interpretation of geophysical logs and existing data determined the placement of screens within each borehole.

  4. Evaluation of geophysical logs and slug tests, phase II, at AIW Frank/Mid-County Mustang Superfund Site, Chester County, Pennsylvania

    Science.gov (United States)

    Conger, R.W.; Goode, D.J.; Sloto, R.A.

    2000-01-01

    Between September 1997 and October 1998, nine monitor wells were drilled at the AIW Frank/Mid-County Mustang Superfund Site in Chester County, Pa., to determine the horizontal and vertical distribution of contaminated ground water migrating from known contaminant sources. The U.S. Geological Survey conducted borehole geophysical logging and borehole television surveys in these boreholes to identify water-producing zones so that appropriate intervals could be screened in each borehole. Caliper logs and borehole television surveys were used to locate fractures; inflections on fluid-temperature and fluid-resistivity logs were used to locate possible water-bearing fractures, and heatpulseflowmeter measurements verified these locations. The borehole television surveys indicated that locally, the rocks of the Conestoga Limestone and Ledger Dolomite that underlie the site strike generally from northeast-southwest to east-west and dip steeply to the southeast and south approximately 63? to 76?. Slug tests were conducted at six boreholes to estimate transmissivity. Transmissivity from slug tests ranged from 21 feet squared per day in borehole CH-5669 to greater than 12,000 feet squared per day in boreholes CH-5665 and CH-5667. After interpretation of geophysical logs, borehole television surveys, and driller's logs, all boreholes were screened such that water-level fluctuations could be monitored and discrete water samples collected from one or more water-producing zones in each borehole.

  5. POST-REMEDIATION BIOMONITORING OF PESTICIDES AND OTHER CONTAMINANTS IN MARINE WATERS AND SEDIMENT NEAR THE UNITED HECKATHORN SUPERFUND SITE, RICHMOND, CALIFORNIA

    Energy Technology Data Exchange (ETDEWEB)

    Antrim, Liam D.; Kohn, Nancy P.

    2000-09-06

    Marine sediment remediation at the United Heckathorn Superfund Site was completed in April 1997. Water and mussel tissues were sampled in February 1999 from four stations near Lauritzen Canal in Richmond, California, for Year 2 of post-remediation monitoring of marine areas near the United Heckathorn Site. Dieldrin and dichlorodiphenyl trichloroethane (DDT) were analyzed in water samples, tissue samples from resident mussels, and tissue samples from transplanted mussels deployed for 4 months. Mussel tissues were also analyzed for polychlorinated biphenyls (PCB), which were detected in sediment samples. Chlorinated pesticide concentrations in water samples were similar to preremediation levels and did not meet remediation goals. Biomonitoring results indicated that the bioavailability of chlorinated pesticides has been reduced from preremediation levels both in the dredged area and throughout Richmond Harbor. Total DDT and dieldrin concentrations in mussel tissues were lower than measured levels from preremediation surveys and also lower than Year 1 levels from post-remediation biomonitoring. Sediment analyses showed the presence of elevated DDT, dieldrin, PCB aroclor 1254, and very high levels of polynuclear aromatic hydrocarbons (PAH) in Lauritzen Channel.

  6. Radiochemical Analyses of the Filter Cake, Granular Activated Carbon, and Treated Ground Water from the DTSC Stringfellow Superfund Site Pretreatment Plant

    Energy Technology Data Exchange (ETDEWEB)

    Esser, B K; McConachie, W; Fischer, R; Sutton, M; Szechenyi, S

    2005-09-16

    The Department of Toxic Substance Control (DTSC) requested that Lawrence Livermore National Laboratory (LLNL) evaluate the treatment process currently employed at the Department's Stringfellow Superfund Site Pretreatment Plant (PTP) site to determine if wastes originating from the site were properly managed with regards to their radioactivity. In order to evaluate the current management strategy, LLNL suggested that DTSC characterize the effluents from the waste treatment system for radionuclide content. A sampling plan was developed; samples were collected and analyzed for radioactive constituents. Following is brief summary of those results and what implications for waste characterization may be made. (1) The sampling and analysis provides strong evidence that the radionuclides present are Naturally Occurring Radioactive Material (NORM). (2) The greatest source of radioactivity in the samples was naturally occurring uranium. The sample results indicate that the uranium concentration in the filter cake is higher than the Granular Activated Carbon (GAC) samples. (11 -14 and 2-6 ppm respectively). (3) No radiologic background for geologic materials has been established for the Stringfellow site, and comprehensive testing of the process stream has not been conducted. Without site-specific testing of geologic materials and waste process streams, it is not possible to conclude if filter cake and spent GAC samples contain radioactivity concentrated above natural background levels, or if radionuclides are being concentrated by the waste treatment process. Recommendation: The regulation of Technologically Enhanced, Naturally Occurring Radioactive Materials (T-NORM) is complex. Since the results of this study do not conclusively demonstrate that natural radioactive materials have not been concentrated by the treatment process it is recommended that the DTSC consult with the Department of Health Services (DHS) Radiological Health Branch to determine if any further

  7. Microbial Diversity and Metal Speciation Changes in Mine Tailings Following Compost-Assisted Direct Planting: A Four-Year Superfund Site Field Study

    Science.gov (United States)

    Maier, R. M.; Gil-Loaiza, J.; Honeker, L. K.; Hottenstein, J. D.; Valentin-Vargas, A.; Jennings, L. L.; Hammond, C.; Neilson, J. W.; Root, R. A.; Chorover, J.

    2015-12-01

    EPA estimates that future mine tailings remediation costs will exceed US $50 billion using present technologies based on constructing an inert or biological cap on the tailings. Both approaches require large amounts of capping materials that can be difficult and expensive to obtain especially for sites several thousand hectares in size. An alternative technology is direct planting into tailings. However, direct planting alone is not feasible for many legacy sites due to extreme acidity and high metal content which prevent plant germination and growth. Therefore the process must be "assisted" through the addition of amendments such as compost. Here we present results from the first four years of a field study at the Iron King Mine and Humboldt Smelter Superfund site demonstrating the feasibility of compost-assisted direct planting. Parameters measured during the field study included: canopy cover, pH, nutrient content, plant metal uptake, metal(loid) speciation, mineral analysis, microbiome analysis, and plant root-metal-microbe interactions. Integrated analysis of these parameters suggests that even in this "worst-case scenario" mine tailings site (pH 2.5; As and Pb each exceeding 2 g kg-1), we have created a sustainable system. In this system, phyto-catalyzed stabilization of inorganic contaminants in the root zone is driven by plant root exudates and the associated rhizosphere microbial community. The results of this research will be put into context of a larger topic- that of ecological engineering of mine tailings sites - a technique being proposed to prevent creation of acidic conditions and metal(loid) mobilization in the first place.

  8. Evaluation of geophysical logs and video surveys in boreholes adjacent to the Berkley Products Superfund Site, West Cocalico Township, Lancaster County, Pennsylvania

    Science.gov (United States)

    Low, Dennis J.; Conger, Randall W.

    1998-01-01

    Between February 1998 and April 1998, geophysical logs were collected in nine boreholes adjacent to the Berkley Products Superfund Site, West Cocalico Township, Lancaster County, Pa. Video surveys were conducted on four of the nine boreholes. The boreholes range in depth from 320 to 508 feet below land surface, are completed open holes, have ambient vertical flow of water, and penetrate a series of interbedded siltstone, sandstone, and conglomerate units. The purpose of collecting geophysical-log data was to help determine horizontal and vertical distribution of contaminated ground water migrating from known or suspected sources and to aid in the placement of permanent borehole packers. The primary contaminants were derived from paint waste that included pigment sludges and wash solvents. The chlorinated volatile organic compounds probably originated from the wash solvents. Caliper logs and video surveys were used to locate fractures; inflections on fluid-resistivity and fluid-temperature logs were used to locate possible water-bearing fractures. Heatpulse-flowmeter measurements were used to verify the locations of water-producing or water-receiving zones and to measure rates of flow between water-bearing fractures. Single-point-resistance and natural-gamma logs provided information on stratigraphy. After interpretation of geophysical logs, video surveys, and driller's logs, permanent multiple-packer systems were installed in each borehole to obtain depth specific water samples from one or more water-bearing fractures in each borehole.

  9. Time series geophysical monitoring of permanganate injections and in situ chemical oxidation of PCE, OU1 area, Savage Superfund Site, Milford, NH, USA.

    Science.gov (United States)

    Harte, Philip T; Smith, Thor E; Williams, John H; Degnan, James R

    2012-05-01

    In situ chemical oxidation (ISCO) treatment with sodium permanganate, an electrically conductive oxidant, provides a strong electrical signal for tracking of injectate transport using time series geophysical surveys including direct current (DC) resistivity and electromagnetic (EM) methods. Effective remediation is dependent upon placing the oxidant in close contact with the contaminated aquifer. Therefore, monitoring tools that provide enhanced tracking capability of the injectate offer considerable benefit to guide subsequent ISCO injections. Time-series geophysical surveys were performed at a superfund site in New Hampshire, USA over a one-year period to identify temporal changes in the bulk electrical conductivity of a tetrachloroethylene (PCE; also called tetrachloroethene) contaminated, glacially deposited aquifer due to the injection of sodium permanganate. The ISCO treatment involved a series of pulse injections of sodium permanganate from multiple injection wells within a contained area of the aquifer. After the initial injection, the permanganate was allowed to disperse under ambient groundwater velocities. Time series geophysical surveys identified the downward sinking and pooling of the sodium permanganate atop of the underlying till or bedrock surface caused by density-driven flow, and the limited horizontal spread of the sodium permanganate in the shallow parts of the aquifer during this injection period. When coupled with conventional monitoring, the surveys allowed for an assessment of ISCO treatment effectiveness in targeting the PCE plume and helped target areas for subsequent treatment.

  10. Occurrences and fate of DDT principal isomers/metabolites, DDA, and o,p'-DDD enantiomers in fish, sediment and water at a DDT-impacted Superfund site.

    Science.gov (United States)

    Garrison, A W; Cyterski, M; Roberts, K D; Burdette, D; Williamson, J; Avants, J K

    2014-11-01

    In the 1950s and 60s, discharges from a DDT manufacturing plant contaminated a tributary system of the Tennessee River near Huntsville, Alabama, USA. Regulatory action resulted in declaring the area a Superfund site which required remediation and extensive monitoring. Monitoring data collected from 1988, after remediation, through 2011 showed annual decreases approximating first-order decay in concentrations of total DDT and its six principal congeners (p,p'-DDT, o,p'-DDT, p,p'-DDD, o,p'-DDD, p,p'-DDE and o,p'-DDE) in filets from three species of fish. As of 2013, these concentrations met the regulatory requirements of 5 mg/kg or less total DDT for each fish tested. The enantiomer fractions (EF) of chiral o,p'-DDD in smallmouth buffalo and channel catfish were always below 0.5, indicating preferential decay of the (+)-enantiomer of this congener; this EF did not change significantly over 15 years. The often-neglected DDT metabolite p,p'-DDA was found at a concentration of about 20 μg/l in the ecosystem water.

  11. Geophysical Logs, Specific Capacity, and Water Quality of Four Wells at Rogers Mechanical (former Tate Andale) Property, North Penn Area 6 Superfund Site, Lansdale, Pennsylvania, 2006-07

    Science.gov (United States)

    Senior, Lisa A.; Bird, Philip H.

    2010-01-01

    As part of technical assistance to the U.S. Environmental Protection Agency (USEPA) in the remediation of properties on the North Penn Area 6 Superfund Site in Lansdale, Pa., the U.S. Geological Survey (USGS) in 2006-07 collected data in four monitor wells at the Rogers Mechanical (former Tate Andale) property. During this period, USGS collected and analyzed borehole geophysical and video logs of three new monitor wells (Rogers 4, Rogers 5, and Rogers 6) ranging in depth from 80 to 180 feet, a borehole video log and additional heatpulse-flowmeter measurements (to quantify vertical borehole flow) in one existing 100-foot deep well (Rogers 3S), and water-level data during development of two wells (Rogers 5 and Rogers 6) to determine specific capacity. USGS also summarized results of passive-diffusion bag sampling for volatile organic compounds (VOCs) in the four wells. These data were intended to help understand the groundwater system and the distribution of VOC contaminants in groundwater at the property.

  12. Time series geophysical monitoring of permanganate injections and in situ chemical oxidation of PCE, OU1 area, Savage Superfund Site, Milford, NH, USA

    Science.gov (United States)

    Harte, Philip T.; Smith, Thor E.; Williams, John H.; Degnan, James R.

    2012-05-01

    In situ chemical oxidation (ISCO) treatment with sodium permanganate, an electrically conductive oxidant, provides a strong electrical signal for tracking of injectate transport using time series geophysical surveys including direct current (DC) resistivity and electromagnetic (EM) methods. Effective remediation is dependent upon placing the oxidant in close contact with the contaminated aquifer. Therefore, monitoring tools that provide enhanced tracking capability of the injectate offer considerable benefit to guide subsequent ISCO injections. Time-series geophysical surveys were performed at a superfund site in New Hampshire, USA over a one-year period to identify temporal changes in the bulk electrical conductivity of a tetrachloroethylene (PCE; also called tetrachloroethene) contaminated, glacially deposited aquifer due to the injection of sodium permanganate. The ISCO treatment involved a series of pulse injections of sodium permanganate from multiple injection wells within a contained area of the aquifer. After the initial injection, the permanganate was allowed to disperse under ambient groundwater velocities. Time series geophysical surveys identified the downward sinking and pooling of the sodium permanganate atop of the underlying till or bedrock surface caused by density-driven flow, and the limited horizontal spread of the sodium permanganate in the shallow parts of the aquifer during this injection period. When coupled with conventional monitoring, the surveys allowed for an assessment of ISCO treatment effectiveness in targeting the PCE plume and helped target areas for subsequent treatment.

  13. Transcriptomic assessment of resistance to effects of an aryl hydrocarbon receptor (AHR agonist in embryos of Atlantic killifish (Fundulus heteroclitus from a marine Superfund site

    Directory of Open Access Journals (Sweden)

    Franks Diana G

    2011-05-01

    Full Text Available Abstract Background Populations of Atlantic killifish (Fundulus heteroclitus have evolved resistance to the embryotoxic effects of polychlorinated biphenyls (PCBs and other halogenated and nonhalogenated aromatic hydrocarbons that act through an aryl hydrocarbon receptor (AHR-dependent signaling pathway. The resistance is accompanied by reduced sensitivity to induction of cytochrome P450 1A (CYP1A, a widely used biomarker of aromatic hydrocarbon exposure and effect, but whether the reduced sensitivity is specific to CYP1A or reflects a genome-wide reduction in responsiveness to all AHR-mediated changes in gene expression is unknown. We compared gene expression profiles and the response to 3,3',4,4',5-pentachlorobiphenyl (PCB-126 exposure in embryos (5 and 10 dpf and larvae (15 dpf from F. heteroclitus populations inhabiting the New Bedford Harbor, Massachusetts (NBH Superfund site (PCB-resistant and a reference site, Scorton Creek, Massachusetts (SC; PCB-sensitive. Results Analysis using a 7,000-gene cDNA array revealed striking differences in responsiveness to PCB-126 between the populations; the differences occur at all three stages examined. There was a sizeable set of PCB-responsive genes in the sensitive SC population, a much smaller set of PCB-responsive genes in NBH fish, and few similarities in PCB-responsive genes between the two populations. Most of the array results were confirmed, and additional PCB-regulated genes identified, by RNA-Seq (deep pyrosequencing. Conclusions The results suggest that NBH fish possess a gene regulatory defect that is not specific to one target gene such as CYP1A but rather lies in a regulatory pathway that controls the transcriptional response of multiple genes to PCB exposure. The results are consistent with genome-wide disruption of AHR-dependent signaling in NBH fish.

  14. SUPERFUND TREATABILITY CLEARINGHOUSE: SUMMARY REPORT ON THE FIELD INVESTIGATION OF THE SAPP BATTERY SITE JACKSON COUNTY, FLORIDA

    Science.gov (United States)

    This treatability study presents the results of field investigations at the Sapp Battery site in Florida, an abandoned battery recycling operation. The site is estimated to contain 14,300 cubic yards of soils with lead levels in excess of 1,000 ppm. The soils in the immediate v...

  15. Post-remediation biomonitoring of pesticides and other contaminants in marine waters and sediment near the United Heckathorn Superfund Site, Richmond, California

    Energy Technology Data Exchange (ETDEWEB)

    LD Antrim; NP Kohn

    2000-05-26

    Marine sediment remediation at the United Heckathorn Superfund Site was completed in April 1997. Water and mussel tissues were sampled in February 1999 from four stations near Lauritzen Canal in Richmond, California, for Year 2 of post-remediation monitoring of marine areas near the United Heckathorn Site. Dieldrin and dichlorodiphenyl trichloroethane (DDT) were analyzed in water samples, tissue samples from resident mussels, and tissue samples from transplanted mussels deployed for 4 months. Concentrations of dieldrin and total DDT in water and total DDT in tissue were compared with Year 1 of post-remediation monitoring, and with preremediation data from the California State Mussel Watch program (tissues) and the Ecological Risk Assessment for the United Heckathorn Superfund Site (tissues and water). Mussel tissues were also analyzed for polychlorinated biphenyls (PCB), which were detected in sediment samples. Chlorinated pesticide concentrations in water samples were similar to preremediation levels and did not meet remediation goals. Mean dieidrin concentrations in water ranged from 0.62 rig/L to 12.5 ng/L and were higher than the remediation goal (0.14 ng/L) at all stations. Mean total DDT concentrations in water ranged from 14.4 ng/L to 62.3 ng/L and exceeded the remediation goal (0.59 ng/L) at all stations. The highest concentrations of both pesticides were found at the Lauritzen Canal/End station. Despite exceedence of the remediation goals, chlorinated pesticide concentrations in Lauritzen Canal water samples were notably lower in 1999 than in 1998. Tissue samples from biomonitoring organisms (mussels) provide an indication of the longer-term integrated exposure to contaminants in the water column, which overcomes the limitations of grab samples of water. Biomonitoring results indicated that the bioavailability of chlorinated pesticides has been reduced from preremediation levels both in the dredged area and throughout Richmond Harbor. Total DDT and

  16. NPL Site Boundaries

    Data.gov (United States)

    U.S. Environmental Protection Agency — The National Priorities List (NPL) is a list published by EPA of Superfund sites. A site must be added to this list before remediation can begin under Superfund. The...

  17. NPL Site Locations

    Data.gov (United States)

    U.S. Environmental Protection Agency — The National Priorities List (NPL) is a list published by EPA of Superfund sites. A site must be added to this list before remediation can begin under Superfund. The...

  18. NPL Site Locations

    Data.gov (United States)

    U.S. Environmental Protection Agency — The National Priorities List (NPL) is a list published by EPA of Superfund sites. A site must be added to this list before remediation can begin under Superfund. The...

  19. Guidance for performing site inspections under CERCLA

    Energy Technology Data Exchange (ETDEWEB)

    1992-09-01

    This guidance presents EPA`s site inspection (SI) strategy. The strategy discusses procedural guidelines to investigate potential Superfund (CERCLA) sites for evaluation pursuant to the Hazard Ranking System (HRS), revised in accordance with the Superfund Amendments and Reauthorization Act of 1986. The HRS is the primary means by which EPA evaluates sites for superfund`s National Priorities List (NPL).

  20. Superfund Technical Assistance Grants

    Data.gov (United States)

    U.S. Environmental Protection Agency — This asset includes data related to the Superfund Technical Assistance Grant program, including grant number, award amounts, award dates, period of performance,...

  1. Water-quality trends and constituent-transport analysis for selected sampling sites in the Milltown Reservoir/Clark Fork River Superfund Site in the upper Clark Fork Basin, Montana, water years 1996–2015

    Science.gov (United States)

    Sando, Steven K.; Vecchia, Aldo V.

    2016-07-20

    During the extended history of mining in the upper Clark Fork Basin in Montana, large amounts of waste materials enriched with metallic contaminants (cadmium, copper, lead, and zinc) and the metalloid trace element arsenic were generated from mining operations near Butte and milling and smelting operations near Anaconda. Extensive deposition of mining wastes in the Silver Bow Creek and Clark Fork channels and flood plains had substantial effects on water quality. Federal Superfund remediation activities in the upper Clark Fork Basin began in 1983 and have included substantial remediation near Butte and removal of the former Milltown Dam near Missoula. To aid in evaluating the effects of remediation activities on water quality, the U.S. Geological Survey began collecting streamflow and water-quality data in the upper Clark Fork Basin in the 1980s.Trend analysis was done on specific conductance, selected trace elements (arsenic, copper, and zinc), and suspended sediment for seven sampling sites in the Milltown Reservoir/Clark Fork River Superfund Site for water years 1996–2015. The most upstream site included in trend analysis is Silver Bow Creek at Warm Springs, Montana (sampling site 8), and the most downstream site is Clark Fork above Missoula, Montana (sampling site 22), which is just downstream from the former Milltown Dam. Water year is the 12-month period from October 1 through September 30 and is designated by the year in which it ends. Trend analysis was done by using a joint time-series model for concentration and streamflow. To provide temporal resolution of changes in water quality, trend analysis was conducted for four sequential 5-year periods: period 1 (water years 1996–2000), period 2 (water years 2001–5), period 3 (water years 2006–10), and period 4 (water years 2011–15). Because of the substantial effect of the intentional breach of Milltown Dam on March 28, 2008, period 3 was subdivided into period 3A (October 1, 2005–March 27, 2008

  2. Environmental Factor(tm) system: Superfund site information from five EPA databases (on cd-rom). Database

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-01

    Environmental Factor puts today`s technology to work to provide a better, more cost-efficient and time-saving way to access EPA information on hazardous waste sites. Environmental consultants, insurers, and reinsurers, corporate risk assessors and companies actively involved in the generation, transport, storage or cleanup of hazardous waste materials can use its user-friendly information retrieval system to gain rapid access to vital information in immediately-usable form. Search, retrieve, and export information in real time. No more waiting for the mail or overnight delivery services to deliver hard copies of voluminous listings and individual site reports. More than 200,000 pages of EPA hazardous waste site information are contained in 5 related databases: (1) Site data from the National Priority List (NPL) and CERCLIS databases, Potentially Responsible Parties (PRP) and Records of Decision (RODs) summaries; (2) Complete PRP information; (3) EPA Records of Decision (Full Text); (4) entire Civil Enforcement Docket; and (5) Glossary of EPA terms, abbreviations and acronyms. Environmental Factor`s powerful database management engine gives even the most inexperienced computer user extensive search capabilities, including wildcard, phonetic and direct cross reference searches across multiple databases. The first menu option delivers information from the NPL, CERCLIS site data, PRP and RODs summary information. Enter a set of search criteria and then immediately access displays containing information from all of these databases. Get full PRP information and Full Text RODs by using their respective menu options. If your search turns up multiple items, a list of site names appears. To bring up the data, highlight the specific site you want and hit Enter. That`s how easy it is to access the vast amount of data stored in the Environmental Factor CD-ROM.

  3. Hydrogeologic characterization and assessment of bioremediation of chlorinated benzenes and benzene in wetland areas, Standard Chlorine of Delaware, Inc. Superfund Site, New Castle County, Delaware, 2009-12

    Science.gov (United States)

    Lorah, Michelle M.; Walker, Charles W.; Baker, Anna C.; Teunis, Jessica A.; Majcher, Emily H.; Brayton, Michael J.; Raffensperger, Jeff P.; Cozzarelli, Isabelle M.

    2014-01-01

    Wetlands at the Standard Chlorine of Delaware, Inc. Superfund Site (SCD) in New Castle County, Delaware, are affected by contamination with chlorobenzenes and benzene from past waste storage and disposal, spills, leaks, and contaminated groundwater discharge. In cooperation with the U.S. Environmental Protection Agency, the U.S. Geological Survey began an investigation in June 2009 to characterize the hydrogeology and geochemistry in the wetlands and assess the feasibility of monitored natural attenuation and enhanced bioremediation as remedial strategies. Groundwater flow in the wetland study area is predominantly vertically upward in the wetland sediments and the underlying aquifer, and groundwater discharge accounts for a minimum of 47 percent of the total discharge for the subwatershed of tidal Red Lion Creek. Thus, groundwater transport of contaminants to surface water could be significant. The major contaminants detected in groundwater in the wetland study area included benzene, monochlorobenzene, and tri- and di-chlorobenzenes. Shallow wetland groundwater in the northwest part of the wetland study area was characterized by high concentrations of total chlorinated benzenes and benzene (maximum about 75,000 micrograms per liter [μg/L]), low pH, and high chloride. In the northeast part of the wetland study area, wetland groundwater had low to moderate concentrations of total chlorinated benzenes and benzene (generally not greater than 10,000 μg/L), moderate pH, and high sulfate concentrations. Concentrations in the groundwater in excess of 1 percent of the solubility of the individual chlorinated benzenes indicate that a contaminant source is present in the wetland sediments as dense nonaqueous phase liquids (DNAPLs). Consistently higher contaminant concentrations in the shallow wetland groundwater than deeper in the wetland sediments or the aquifer also indicate a continued source in the wetland sediments, which could include dissolution of DNAPLs and

  4. 76 FR 72405 - San Fernando Valley Area 2 Superfund Site; Notice of Proposed Prospective Purchaser Agreement Re...

    Science.gov (United States)

    2011-11-23

    ... Site; Notice of Proposed Prospective Purchaser Agreement Re: 4057 and 4059 Goodwin Avenue, Los Angeles...) concerning 4057 and 4059 Goodwin Avenue, Los Angeles, California (Property). The Agreement is entered into..., Glendale/Goodwin Realty I, LLC, an Ohio limited liability company, The Kroger Co., an Ohio corporation,...

  5. Water-quality trends and constituent-transport analysis for selected sampling sites in the Milltown Reservoir/Clark Fork River Superfund Site in the upper Clark Fork Basin, Montana, water years 1996–2015

    Science.gov (United States)

    Sando, Steven K.; Vecchia, Aldo V.

    2016-07-20

    During the extended history of mining in the upper Clark Fork Basin in Montana, large amounts of waste materials enriched with metallic contaminants (cadmium, copper, lead, and zinc) and the metalloid trace element arsenic were generated from mining operations near Butte and milling and smelting operations near Anaconda. Extensive deposition of mining wastes in the Silver Bow Creek and Clark Fork channels and flood plains had substantial effects on water quality. Federal Superfund remediation activities in the upper Clark Fork Basin began in 1983 and have included substantial remediation near Butte and removal of the former Milltown Dam near Missoula. To aid in evaluating the effects of remediation activities on water quality, the U.S. Geological Survey began collecting streamflow and water-quality data in the upper Clark Fork Basin in the 1980s.Trend analysis was done on specific conductance, selected trace elements (arsenic, copper, and zinc), and suspended sediment for seven sampling sites in the Milltown Reservoir/Clark Fork River Superfund Site for water years 1996–2015. The most upstream site included in trend analysis is Silver Bow Creek at Warm Springs, Montana (sampling site 8), and the most downstream site is Clark Fork above Missoula, Montana (sampling site 22), which is just downstream from the former Milltown Dam. Water year is the 12-month period from October 1 through September 30 and is designated by the year in which it ends. Trend analysis was done by using a joint time-series model for concentration and streamflow. To provide temporal resolution of changes in water quality, trend analysis was conducted for four sequential 5-year periods: period 1 (water years 1996–2000), period 2 (water years 2001–5), period 3 (water years 2006–10), and period 4 (water years 2011–15). Because of the substantial effect of the intentional breach of Milltown Dam on March 28, 2008, period 3 was subdivided into period 3A (October 1, 2005–March 27, 2008

  6. multilevel buck converter for automotive electrical load

    African Journals Online (AJOL)

    user

    development of DCM based buck converter and its applications in the HEVs/EVs using ... The paper also highlights the implications of implementing a single stage buck converter, and ..... instance when the saw tooth signal within the internal.

  7. Bidirectional buck boost converter

    Science.gov (United States)

    Esser, Albert Andreas Maria

    1998-03-31

    A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero.

  8. Geologic Controls of Sand Boil Formation at Buck Chute, Mississippi

    Science.gov (United States)

    2017-06-30

    Geology ........................................................................................................................... 4 2.3 Description of...18 3.1 Geology of the Lower Mississippi River Valley...Hypothesis Sand boil formation at the Buck Chute site is the result of geology consisting of point bar and abandoned channel deposits with a thin

  9. Hydrogeology and simulation of ground-water flow at the Gettysburg Elevator Plant Superfund Site, Adams County, Pennsylvania

    Science.gov (United States)

    Low, Dennis J.; Goode, Daniel J.; Risser, Dennis W.

    2000-01-01

    Ground water in Triassic-age sedimentary fractured-rock aquifers in the area of Gettysburg, Pa., is used as drinking water and for industrial and commercial supply. In 1983, ground water at the Gettysburg Elevator Plant was found by the Pennsylvania Department of Environmental Resources to be contaminated with trichloroethene, 1,1,1-trichloroethane, and other synthetic organic compounds. As part of the U.S. Environmental Protection Agency?s Comprehensive Environmental Response, Compensation, and Liability Act, 1980 process, a Remedial Investigation was completed in July 1991, a method of site remediation was issued in the Record of Decision dated June 1992, and a Final Design Report was completed in May 1997. In cooperation with the U.S. Environmental Protection Agency in the hydrogeologic assessment of the site remediation, the U.S. Geological Survey began a study in 1997 to determine the effects of the onsite and offsite extraction wells on ground-water flow and contaminant migration from the Gettysburg Elevator Plant. This determination is based on hydrologic and geophysical data collected from 1991 to 1998 and on results of numerical model simulations of the local ground-water flow-system. The Gettysburg Elevator Site is underlain by red, green, gray, and black shales of the Heidlersburg Member of the Gettysburg Formation. Correlation of natural-gamma logs indicates the sedimentary rock strike about N. 23 degrees E. and dip about 23 degrees NW. Depth to bedrock onsite commonly is about 6 feet but offsite may be as deep as 40 feet. The ground-water system consists of two zones?a thin, shallow zone composed of soil, clay, and highly weathered bedrock and a thicker, nonweathered or fractured bedrock zone. The shallow zone overlies the bedrock zone and truncates the dipping beds parallel to land surface. Diabase dikes are barriers to ground-water flow in the bedrock zone. The ground-water system is generally confined or semi-confined, even at shallow depths. Depth

  10. Temporal Chemical Data for Sediment, Water, and Biological Samples from the Lava Cap Mine Superfund Site, Nevada County, California-2006-2008

    Science.gov (United States)

    Foster, Andrea L.; Ona-Nguema, Georges; Tufano, Kate; White, Richard III

    2010-01-01

    the possibility of future movement of tailings, and began an assessment of the risks posed by physical and chemical hazards at the site. The EPA's assessment identified arsenic (As) as the primary hazard of concern. Three main exposure routes were identified: inhalation/ingestion of mine tailings, dermal absorption/ingestion of As in lake water from swimming, and ingestion of As-contaminated ground water or surface water. Lost Lake is a private lake which is completely surrounded by low-density residential development. Prior to the dam failure, the lake was used by the local residents for swimming and boating. An estimated 1,776 people reside within one mile of the lake, and almost all residents of the area use potable groundwater for domestic use. Risk factors for human exposure to As derived from mine wastes were high enough to merit placement of the mine site and surrounding area on the National Priority List (commonly called ?Superfund?). The Lava Cap Mine Superfund site (LCMS) encompasses approximately 33 acres that include the mine site, the stretch of Little Clipper Creek between the mine and Lost Lake, the lake itself, and the area between the lake and the confluence of Little Clipper Creek with its parent stream, Clipper Creek. The area between the two creeks is named the ?deposition area? due to the estimated 24 m thick layer of tailings that were laid down there during and after active mining. The lobate structure of Lost Lake is also due to deposition in this area. The deposition area and Lost Lake are together estimated to contain 382,277 m3 of tailings. The primary goals of the EPA have been to minimize tailings movement downstream of Lost Lake and to ensure that residents in the area have drinking water that meets national water quality standards. EPA has officially decided to construct a public water supply line to deliver safe water to affected residences, since some residential wells in the area have As concentrations above the curr

  11. Geochemical Characterization of Mine Waste, Mine Drainage, and Stream Sediments at the Pike Hill Copper Mine Superfund Site, Orange County, Vermont

    Science.gov (United States)

    Piatak, Nadine M.; Seal, Robert R.; Hammarstrom, Jane M.; Kiah, Richard G.; Deacon, Jeffrey R.; Adams, Monique; Anthony, Michael W.; Briggs, Paul H.; Jackson, John C.

    2006-01-01

    The Pike Hill Copper Mine Superfund Site in the Vermont copper belt consists of the abandoned Smith, Eureka, and Union mines, all of which exploited Besshi-type massive sulfide deposits. The site was listed on the U.S. Environmental Protection Agency (USEPA) National Priorities List in 2004 due to aquatic ecosystem impacts. This study was intended to be a precursor to a formal remedial investigation by the USEPA, and it focused on the characterization of mine waste, mine drainage, and stream sediments. A related study investigated the effects of the mine drainage on downstream surface waters. The potential for mine waste and drainage to have an adverse impact on aquatic ecosystems, on drinking- water supplies, and to human health was assessed on the basis of mineralogy, chemical concentrations, acid generation, and potential for metals to be leached from mine waste and soils. The results were compared to those from analyses of other Vermont copper belt Superfund sites, the Elizabeth Mine and Ely Copper Mine, to evaluate if the waste material at the Pike Hill Copper Mine was sufficiently similar to that of the other mine sites that USEPA can streamline the evaluation of remediation technologies. Mine-waste samples consisted of oxidized and unoxidized sulfidic ore and waste rock, and flotation-mill tailings. These samples contained as much as 16 weight percent sulfides that included chalcopyrite, pyrite, pyrrhotite, and sphalerite. During oxidation, sulfides weather and may release potentially toxic trace elements and may produce acid. In addition, soluble efflorescent sulfate salts were identified at the mines; during rain events, the dissolution of these salts contributes acid and metals to receiving waters. Mine waste contained concentrations of cadmium, copper, and iron that exceeded USEPA Preliminary Remediation Goals. The concentrations of selenium in mine waste were higher than the average composition of eastern United States soils. Most mine waste was

  12. Evaluation of geophysical logs and aquifer-isolation tests, Phase III, August 2002 to March 2004, Crossley Farm superfund site, Hereford township, Berks County, Pennsylvania

    Science.gov (United States)

    Conger, Randall W.; Low, Dennis J.

    2006-01-01

    Between August 2002 and March 2004, geophysical logging was conducted in 23 boreholes at the Crossley Farm Superfund Site, Hereford Township, Berks County, Pa., to determine the water-producing zones, water-receiving zones, zones of vertical-borehole flow, and fracture orientation where applicable. The boreholes ranged in depth from 71 to 503 ft(feet) below land surface. The geophysical logging determined the placement of well screens and packers, which allow monitoring and sampling of water-bearing zones in the fractured bedrock so the horizontal and vertical distribution of contaminated ground water migrating from known sources could be determined. Geophysical logging included collection of caliper (22 boreholes), fluid-temperature (17 boreholes),single-point-resistance (17 boreholes), natural-gamma (17 boreholes), fluid-flow (18 boreholes), and acoustic-televiewer (13 boreholes) logs. Caliper and acoustic-televiewer logs were used to locate fractures, joints, and weathered zones. Inflections on fluid-temperature and single-point-resistance logs indicated possible water-bearing zones, and flowmeter measurements verified these locations. Single-point-resistance, natural-gamma, and geologist logs provided information on stratigraphy; the geologist log also provided information on the location of possible water-producing zones. Borehole geophysical logging and heatpulse flowmetering indicated active flow in 10 boreholes. Seven of the boreholes are in ground-water discharge areas and three boreholes are in ground-water recharge areas. Heatpulse flowmetering, in conjunction with the geologist logs, indicates lithologic contacts (changes in lithology from a gneiss dominated by quartz-plagioclase-feldspar mineralogy to a gneiss dominated by hornblende mineralogy) are typically fractured, permeable, and effective transmitters of water. Single-well, aquifer-isolation (packer) tests were performed on two boreholes. Packers were set at depths ranging from 210 to 465 ft

  13. Geochemical, isotopic, and dissolved gas characteristics of groundwater in a fractured crystalline-rock aquifer, Savage Municipal Well Superfund site, Milford, New Hampshire, 2011

    Science.gov (United States)

    Harte, Philip T.

    2013-01-01

    Tetrachloroethylene (PCE), a volatile organic compound, was detected in groundwater from deep (more than (>) 300 feet (ft) below land surface) fractures in monitoring wells tapping a crystalline-rock aquifer beneath operable unit 1 (OU1) of the Savage Municipal Well Superfund site (Weston, Inc., 2010). Operable units define remedial areas of contaminant concern. PCE contamination within the fractured-rock aquifer has been designated as a separate operable unit, operable unit 3 (OU3; Weston, Inc., 2010). PCE contamination was previously detected in the overlying glacial sand and gravel deposits and basal till, hereafter termed the Milford-Souhegan glacial-drift (MSGD) aquifer (Harte, 2004, 2006). Operable units 1 and 2 encompass areas within the MSGD aquifer, whereas the extent of the underlying OU3 has yet to be defined. The primary original source of contamination has been identified as a former manufacturing facility—the OK Tool manufacturing facility; hence OU1 sometimes has been referred to as the OK Tool Source Area (New Hampshire Department of Environmental Services, undated). A residential neighborhood of 30 to 40 houses is located in close proximity (one-quarter of a mile) from the PCE-contaminated monitoring wells. Each house has its own water-supply well installed in similar rocks as those of the monitoring wells, as indicated by the New Hampshire State geologic map (Lyons and others, 1997). An investigation was initiated in 2010 by the U.S. Environmental Protection Agency (USEPA) region 1, and the New Hampshire Department of Environmental Services (NHDES) to assess the potential for PCE transport from known contaminant locations (monitoring wells) to the residential wells. The U.S. Geological Survey (USGS) and the NHDES entered into a cooperative agreement in 2011 to assist in the evaluation of PCE transport in the fractured-rock aquifer. Periodic sampling over the last decade by the USEPA and NHDES has yet to detect PCE in groundwater from the

  14. Bucking Trends: Expanding the Arts

    Science.gov (United States)

    Levin, Kathi R.

    2008-01-01

    The arts and music have been unintended victims of the No Child Left Behind Act. Several reports point to sharp reductions in student access to K-12 arts education, yet some school districts nationwide have managed to buck the trend. These districts, in communities rural through urban, are systemically embedding the arts at the core of teaching…

  15. Superfund and Toxic Release Inventory Sites - INSTITUTIONAL_CONTROLS_IDEM_IN.SHP: Institutional Control Sites in Indiana (Indiana Department of Environmental Management, Polygon Shapefile)

    Data.gov (United States)

    NSGIC State | GIS Inventory — INSTITUTIONAL_CONTROLS_IDEM_IN is a polygon shapefile that contains Institutional Control (IC) site locations in Indiana, provided by personnel of Indiana Department...

  16. Hydrogeologic framework, arsenic distribution, and groundwater geochemistry of the glacial-sediment aquifer at the Auburn Road landfill superfund site, Londonderry, New Hampshire

    Science.gov (United States)

    Degnan, James R.; Harte, Philip T.

    2013-01-01

    Leachate continues to be generated from landfills at the Auburn Road Landfill Superfund Site in Londonderry, New Hampshire. Impermeable caps on the three landfills at the site inhibit direct infiltration of precipitation; however, high water-table conditions allow groundwater to interact with landfill materials from below, creating leachate and ultimately reducing conditions in downgradient groundwater. Reducing conditions can facilitate arsenic transport by allowing it to stay in solution or by liberating arsenic adsorbed to surfaces and from geologic sources, such as glacial sediments and bedrock. The site occupies a 180-acre parcel of land containing streams, ponds, wetlands, and former gravel pits located in glacial sediment. Four areas, totaling 14 acres, including three landfills and one septage lagoon, were used for waste disposal. The site was closed in 1980 after volatile organic compounds associated with industrial waste dumping were detected. The site was added to the U.S. Environmental Protection Agency National Priority List in 1982, and the landfills were capped in 1996. Although volatile organic compound concentrations in groundwater have declined substantially, some measurable concentrations remain. Temporally variable and persistent elevated arsenic concentrations have been measured in groundwater affected by the landfill leachate. Microbial consumption of carbon found in leachate is a driver of reducing conditions that liberate arsenic at the site. In addition to sources of carbon in landfill leachate, wetland areas throughout the site also could contribute carbon to groundwater, but it is currently unknown if any of the wetland areas have downward or reversing gradients that could allow the infiltration of surface water to groundwater. Red-stained sediments and water indicate iron-rich groundwater discharge to surface water and are also associated with elevated concentrations of arsenic in sediment and groundwater. Ironrich groundwater seeps have

  17. Geophysical Logs, Aquifer Tests, and Water Levels in Wells in and Near the North Penn Area 7 Superfund Site, Upper Gwynedd Township, Montgomery County, Pennsylvania, 2002-2006

    Science.gov (United States)

    Senior, Lisa A.; Conger, Randall W.; Bird, Philip H.

    2008-01-01

    Ground water in the vicinity of several industrial facilities in Upper Gwynedd Township and Lansdale Borough, Montgomery County, Pa., is contaminated with several volatile organic compounds (VOCs). The 2-square-mile area was placed on the National Priorities List as the North Penn Area 7 Superfund Site by the U.S. Environmental Protection Agency (USEPA) in 1989. The U.S. Geological Survey (USGS) conducted geophysical logging, aquifer testing, water-level monitoring, and streamflow measurements in the vicinity of North Penn Area 7 from October 2002 through December 2006. This followed work that began in 2000 to assist the USEPA in developing an understanding of the hydrogeologic framework in the area as part of the USEPA Remedial Investigation. The study area is underlain by Triassic- and Jurassic-age sandstones, siltstones, and shales of the Lockatong Formation and the Brunswick Group. Regionally, these rocks strike northeast and dip to the northwest. The sequence of rocks form fractured-rock aquifers that act as a set of confined to semi-confined layered aquifers of differing permeabilities. The aquifers are recharged by precipitation and discharge to streams and wells. The Wissahickon Creek headwaters are less than 1 mile northeast of the study area. This stream flows southwest approximately parallel to strike and bisects North Penn Area 7. Ground water is pumped in the vicinity of North Penn Area 7 for industrial use and public supply. The USGS collected geophysical logs for 42 wells that ranged in depth from 40 to 477 ft. Aquifer-interval-isolation testing was done in 17 of the 42 wells, for a total of 122 zones tested. A multiple-well aquifer test was conducted by monitoring the response of 14 wells to pumping and shutdown of a 600-ft deep production well in November-December 2004. In addition, water levels were monitored continuously in four wells in the area from October 2002 through September 2006, and streamflow was measured quarterly at two sites on

  18. Hydrostratigraphic mapping of the Milford-Souhegan glacial drift aquifer, and effects of hydrostratigraphy on transport of PCE, Operable Unit 1, Savage Superfund Site, Milford, New Hampshire

    Science.gov (United States)

    Harte, Philip T.

    2010-01-01

    The Savage Municipal Well Superfund site in the Town of Milford, New Hampshire, was underlain by a 0.5-square mile plume (as mapped in 1994) of volatile organic compounds (VOCs), most of which consisted of tetrachloroethylene (PCE). The plume occurs mostly within highly transmissive stratified-drift deposits but also extends into underlying till and bedrock. The plume has been divided into two areas called Operable Unit 1 (OU1), which contains the primary source area, and Operable Unit 2 (OU2), which is defined as the extended plume area outside of OU1. The OU1 remedial system includes a low-permeability barrier wall that encircles the highest detected concentrations of PCE and a series of injection and extraction wells to contain and remove contaminants. The barrier wall likely penetrates the full thickness of the sand and gravel; in many places, it also penetrates the full thickness of the underlying basal till and sits atop bedrock.From 1998 to 2004, PCE concentrations decreased by an average of 80 percent at most wells outside the barrier wall. However, inside the barrier, PCE concentrations greater than 10,000 micrograms per liter (μg/L) still exist (2008). The remediation of these areas of recalcitrant PCE presents challenges to successful remediation.The U.S. Geological Survey (USGS), in cooperation with the New Hampshire Department of Environmental Services (NHDES) and the U.S. Environmental Protection Agency (USEPA), Region 1, is studying the solute transport of VOCs (primarily PCE) in contaminated groundwater in the unconsolidated sediments (overburden) of the Savage site and specifically assisting in the evaluation of the effectiveness of remedial operations in the OU1 area. As part of this effort, the USGS analyzed the subsurface stratigraphy to help understand hydrostratigraphic controls on remediation.A combination of lithologic, borehole natural gamma-ray and electromagnetic (EM) induction logging, and test drilling has identified 11 primary

  19. Technology evaluation report: SITE (Superfund Innovative Technology Evaluation) program demonstration test. The American Combustion Pyretron Thermal Destruction System at the US EPA's (Environmental Protection Agency's) combustion research facility

    Energy Technology Data Exchange (ETDEWEB)

    Waterland, L.; Lee, J.W.

    1989-04-01

    A series of demonstration tests of the American Combustion, Inc., Thermal Destruction System was performed under the SITE program. This oxygen-enhanced combustion system was retrofit to the rotary-kiln incinerator at EPA's Combustion Research Facility. The system's performance was tested firing contaminated soil from the Stringfellow Superfund Site, both alone and mixed with a coal tar waste (KO87). Comparative performance with conventional incinerator operation was also tested. Compliance with the incinerator performance standards of 99.99% principal organic hazardous constituents (POHC) destruction and removal efficiency and particulate emissions of less than 180 mg/dscm at 7% O2 was measured for all tests. The Pyretron system was capable of in-compliance performance at double the mixed waste feedrate and at a 60% increase in batch waste charge mass than possible with conventional incineration. Scrubber blowdown and kiln ash contained no detectable levels of any of the POHCs chosen.

  20. Buck-Buck- Boost Regulatr (B3R)

    Science.gov (United States)

    Mourra, Olivier; Fernandez, Arturo; Landstroem, Sven; Tonicello, Ferdinando

    2011-10-01

    In a satellite, the main function of a Power Conditioning Unit (PCU) is to manage the energy coming from several power sources (usually solar arrays and battery) and to deliver it continuously to the users in an appropriate form during the overall mission. The objective of this paper is to present an electronic switching DC-DC converter called Buck-Buck-Boost Regulator (B3R) that could be used as a modular and recurrent solution in a PCU for regulated or un- regulated 28Vsatellite power bus classes. The power conversion stages of the B3R topology are first described. Then theoretical equations and practical tests illustrate how the converter operates in term of power conversion, control loops performances and efficiency. The paper finally provides some examples of single point failure tolerant implementation using the B3R.

  1. A cross-site comparison of methods used for hydrogeologic characterization of the Galena-Platteville aquifer in Illinois and Wisconsin, with examples from selected Superfund sites

    Science.gov (United States)

    Kay, Robert T.; Mills, Patrick C.; Dunning, Charles P.; Yeskis, Douglas J.; Ursic, James R.; Vendl, Mark

    2004-01-01

    The effectiveness of 28 methods used to characterize the fractured Galena-Platteville aquifer at eight sites in northern Illinois and Wisconsin is evaluated. Analysis of government databases, previous investigations, topographic maps, aerial photographs, and outcrops was essential to understanding the hydrogeology in the area to be investigated. The effectiveness of surface-geophysical methods depended on site geology. Lithologic logging provided essential information for site characterization. Cores were used for stratigraphy and geotechnical analysis. Natural-gamma logging helped identify the effect of lithology on the location of secondary- permeability features. Caliper logging identified large secondary-permeability features. Neutron logs identified trends in matrix porosity. Acoustic-televiewer logs identified numerous secondary-permeability features and their orientation. Borehole-camera logs also identified a number of secondary-permeability features. Borehole ground-penetrating radar identified lithologic and secondary-permeability features. However, the accuracy and completeness of this method is uncertain. Single-point-resistance, density, and normal resistivity logs were of limited use. Water-level and water-quality data identified flow directions and indicated the horizontal and vertical distribution of aquifer permeability and the depth of the permeable features. Temperature, spontaneous potential, and fluid-resistivity logging identified few secondary-permeability features at some sites and several features at others. Flowmeter logging was the most effective geophysical method for characterizing secondary-permeability features. Aquifer tests provided insight into the permeability distribution, identified hydraulically interconnected features, the presence of heterogeneity and anisotropy, and determined effective porosity. Aquifer heterogeneity prevented calculation of accurate hydraulic properties from some tests. Different methods, such as flowmeter

  2. Assessment of subsurface chlorinated solvent contamination using tree cores at the front street site and a former dry cleaning facility at the Riverfront Superfund site, New Haven, Missouri, 1999-2003

    Science.gov (United States)

    Schumacher, John G.; Struckhoff, Garrett C.; Burken, Joel G.

    2004-01-01

    Tree-core sampling has been a reliable and inexpensive tool to quickly assess the presence of shallow (less than about 30 feet deep) tetrachloroethene (PCE) and trichloroethene (TCE) contamination in soils and ground water at the Riverfront Superfund Site. This report presents the results of tree-core sampling that was successfully used to determine the presence and extent of chlorinated solvent contamination at two sites, the Front Street site (operable unit OU1) and the former dry cleaning facility, that are part of the overall Riverfront Superfund Site. Traditional soil and ground-water sampling at these two sites later confirmed the results from the tree-core sampling. Results obtained from the tree-core sampling were used to design and focus subsequent soil and ground-water investigations, resulting in substantial savings in time and site assessment costs. The Front Street site is a small (less than 1-acre) site located on the Missouri River alluvium in downtown New Haven, Missouri, about 500 feet from the south bank of the Missouri River. Tree-core sampling detected the presence of subsurface PCE contamination at the Front Street site and beneath residential property downgradient from the site. Core samples from trees at the site contained PCE concentrations as large as 3,850 mg-h/kg (micrograms in headspace per kilogram of wet core) and TCE concentrations as large as 249 mg-h/kg. Soils at the Front Street site contained PCE concentrations as large as 6,200,000 mg/kg (micrograms per kilogram) and ground-water samples contained PCE concentrations as large as 11,000 mg/L (micrograms per liter). The former dry cleaning facility is located at the base of the upland that forms the south bank of the Missouri River alluvial valley. Tree-core sampling did not indicate the presence of PCE or TCE contamination at the former dry cleaning facility, a finding that was later confirmed by the analyses of soil samples collected from the site. The lateral extent of PCE

  3. Conference James F.Buckli

    CERN Multimedia

    Buckli,J

    1988-01-01

    L'association du personnel a le plaisir d'accueillir Mons. James F.Buckli, astronaute, né en 1947. Il a participé à la mission Space Lab D1 qui pour la première fois mettait 8 personnes sur orbite.L'ass.du pers. remercie aussi Gordon White(s) de la mission américaine d'avoir permis d'organiser cette conférence

  4. Evaluation of modeling for groundwater flow and tetrachloroethylene transport in the Milford-Souhegan glacial-drift aquifer at the Savage Municipal Well Superfund site, Milford, New Hampshire, 2011

    Science.gov (United States)

    Harte, Philip T.

    2012-01-01

    The U.S. Geological Survey and the New Hampshire Department of Environmental Services entered into a cooperative agreement to assist in the evaluation of remedy simulations of the MSGD aquifer that are being performed by various parties to track the remedial progress of the PCE plume. This report summarizes findings from this evaluation. Topics covered include description of groundwater flow and transport models used in the study of the Savage Superfund site (section 2), evaluation of models and their results (section 3), testing of several new simulations (section 4), an assessment of the representation of models to simulate field conditions (section 5), and an assessment of models as a tool in remedial operational decision making (section 6).

  5. 75 FR 49414 - Cooperative Agreements and Superfund State Contracts for Superfund Response Actions

    Science.gov (United States)

    2010-08-13

    ... AGENCY 40 CFR Part 35 RIN 2050-AG58 Cooperative Agreements and Superfund State Contracts for Superfund... Superfund Cooperative Agreements and Superfund State Contracts. DATES: This rule is effective October 12... requirements shall apply to all new Cooperative Agreements and Superfund State Contracts, funded under...

  6. Series Connected Buck-Boost Regulator

    Science.gov (United States)

    Birchenough, Arthur G. (Inventor)

    2006-01-01

    A Series Connected Buck-Boost Regulator (SCBBR) that switches only a fraction of the input power, resulting in relatively high efficiencies. The SCBBR has multiple operating modes including a buck, a boost, and a current limiting mode, so that an output voltage of the SCBBR ranges from below the source voltage to above the source voltage.

  7. Simulation of solute transport of tetrachloroethylene in ground water of the glacial-drift aquifer at the Savage Municipal Well Superfund Site, Milford, New Hampshire, 1960-2000

    Science.gov (United States)

    Harte, Philip T.

    2004-01-01

    The Savage Municipal Well Superfund site, named after the former municipal water-supply well for the town of Milford, is underlain by a 0.5-square mile plume of volatile organic compounds (VOCs), primarily tetrachloroethylene (PCE). The plume occurs mostly within a highly transmissive sand-and-gravel unit, but also extends to an underlying till and bedrock unit. The plume logistically is divided into two areas termed Operable Unit No. 1 (OU1), which contains the primary source area, and Operable Unit No. 2 (OU2), which is the extended plume area. PCE concentrations in excess of 100,000 parts per billion (ppb) had been detected in the OU1 area in 1995, indicating a likely Dense Non-Aqueous Phase Liquid (DNAPL) source. In the fall of 1998, the New Hampshire Department of Environmental Services (NHDES) and the U.S. Environmental Protection Agency (USEPA) installed a remedial system in OU1. The OU1 remedial system includes a low-permeability barrier that encircles the highest detected concentrations of PCE, and a series of injection and extraction wells. The barrier primarily sits atop bedrock and penetrates the full thickness of the sand and gravel; and in some places, the full thickness of the underlying basal till. The sand and gravel unit and the till comprise the aquifer termed the Milford-Souhegan glacial-drift aquifer (MSGD). Two-dimensional and three-dimensional finite-difference solute-transport models of the unconsolidated sediments (MSGD aquifer) were constructed to help evaluate solute-transport processes, assess the effectiveness of remedial activities in OU1, and to help design remedial strategies in OU2. The solute-transport models simulate PCE concentrations, and model results were compared to observed concentrations of PCE. Simulations were grouped into the following three time periods: an historical calibration of the distribution of PCE from the initial input (circa 1960) of PCE into the subsurface to the 1990s, a pre-remedial calibration from 1995

  8. Borehole geophysical logging and aquifer-isolation tests conducted in well MG-1693 at North Penn Area 5 Superfund Site near Colmar, Montgomery County, Pennsylvania

    Science.gov (United States)

    Bird, Philip H.

    2006-01-01

    Borehole geophysical logging and aquifer-isolation (packer) tests were conducted in well MG-1693 (NP-87) at the North Penn Area 5 Superfund Site near Colmar, Montgomery County, Pa. Objectives of the study were to identify the depth and yield of water-bearing zones, occurrence of vertical borehole flow, and effects of pumping on water levels in nearby wells. Caliper, natural-gamma, single-point-resistance, fluid-temperature, fluid-resistivity, heatpulse-flowmeter, and borehole-video logs were collected. Vertical borehole-fluid movement direction and rate were measured under nonpumping conditions. The suite of logs was used to locate water-bearing fractures, determine zones of vertical borehole-fluid movement, and select depths to set packers. Aquifer-isolation tests were conducted to sample discrete intervals and to determine specific capacities of water-bearing zones and effects of pumping individual zones on water levels in two nearby monitor wells. Specific capacities of isolated zones during aquifer-isolation tests ranged from 0.03 to 3.09 (gal/min)/ft (gallons per minute per foot). Fractures identified by borehole geophysical methods as water-producing or water-receiving zones produced water when isolated and pumped. Water enters the borehole primarily through high-angle fractures at 416 to 435 ft bls (feet below land surface) and 129 to 136 ft bls. Water exits the borehole through a high-angle fracture at 104 to 107 ft bls, a broken casing joint at 82 ft bls, and sometimes as artesian flow through the top of the well. Thirteen intervals were selected for aquifer-isolation testing, using a straddle-packer assembly. The specific capacity of interval 1 was 2.09 (gal/min)/ft. The specific capacities of intervals 2, 3, and 4 were similar: 0.27, 0.30, and 0.29 (gal/min)/ft,respectively. The specific capacities of intervals 5, 6, 7, 8, and 10 were similar: 0.03, 0.04, 0.09, 0.09, and 0.04 (gal/min)/ft,respectively. Intervals 9, 11, and 12 each showed a strong

  9. Results of a monitoring program of continuous water levels and physical water properties at the Operable Unit 1 area of the Savage Municipal Well Superfund site, Milford, New Hampshire, water years 2000-03

    Science.gov (United States)

    Harte, Philip T.

    2005-01-01

    The Milford-Souhegan glacial-drift (MSGD) aquifer, in south-central New Hampshire, is an important source of industrial, commercial, and domestic water. The MSGD aquifer was also an important source of drinking water for the town of Milford until it was found to contain high concentrations of volatile organic compounds (VOCs) in the Savage and Keyes municipal-supply wells in the early 1980s. A VOC plume was found to cover part of the southwestern half of the MSGD aquifer. In September 1984, the site was designated a Superfund site, called the Savage Municipal Well Superfund site. The primary source area of contaminants was a former tool manufacturing facility (called the OK Tool facility, and now called the Operable Unit 1 (OU1) area) that disposed of solvents at the surface and in the subsurface. The facility was closed in 1987 and removed in 1998. A low-permeability containment barrier wall was constructed and installed in the overburden (MSGD aquifer) in 1998 to encapsulate the highest concentrations of VOCs, and a pump-and-treat remediation facility was also added. Remedial operations of extraction and injection wells started in May 1999. A network of water-level monitoring sites was implemented in water year 2000 (October 1, 1999, through September 30, 2000) in the OU1 area to help assess the effectiveness of remedial operations to mitigate the VOC plume, and to evaluate the effect of the barrier wall and remedial operations on the hydraulic connections across the barrier and between the overburden and underlying bedrock. Remedial extraction and injections wells inside and outside the barrier help isolate ground-water flow inside the barrier and the further spreading of VOCs. This report summarizes both continuous and selected periodic manual measurements of water level and physical water properties (specific conductance and water temperature) for 10 monitoring locations during water years 2000-03. Additional periodic manual measurements of water levels were

  10. Site Features

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset consists of various site features from multiple Superfund sites in U.S. EPA Region 8. These data were acquired from multiple sources at different times...

  11. Region 9 Removal Sites

    Data.gov (United States)

    U.S. Environmental Protection Agency — Point geospatial dataset representing locations of CERCLA (Superfund) Removal sites. CERCLA (Comprehensive Environmental Response, Compensation, and Liability Act)...

  12. Report: EPA’s Distribution of Superfund Human Resources Does Not Support Current Regional Workload

    Science.gov (United States)

    Report #17-P-0397, September 19, 2017. Due to insufficient human resources to cover all Superfund site work, some regions have had to slow down or discontinue their efforts to protect human health and the environment.

  13. SUPERFUND TREATABILITY CLEARINGHOUSE: BDAT INCINERATION OF CERCLA SARMS AT THE JOHN ZINK COMPANY TEST FACILITY (FINAL PROJECT REPORT)

    Science.gov (United States)

    This report presents the results of a treatability study of rotary kiln incineration of a synthetic "Superfund soil" bearing a wide range of chemical contaminants typically occurring at Superfund sites. This surrogate soil is referred to as a synthetic analytical reference ...

  14. Sediment magnetic and paleomagnetic data from Buck Lake, Oregon

    Science.gov (United States)

    Rosenbaum, J.G.; Reynolds, R.L.; Fitzmaurice, P.L.; Drexler, J.W.; Whitney, C.G.; Adam, D.P.

    1994-01-01

    Sediment magnetic and paleomagnetic studies were conducted on a core from Buck Lake, Klamath County, Oregon, that was collected as part of an investigation into the Quaternary climate history of the western United States. This report documents the methods used to obtain paleomagnetic directions, magnetic properties, and ancillary data, and presents these data in tabular form. Adam (1993) and Adam and others (1994) describe the site, the drilling methods, and lithology of the lacustrine sediments. Rosenbaum and others (1994) present preliminary interpretations of the sediment magnetic data and show that variations in magnetic properties closely reflect changes in climate as interpreted from the pollen record.

  15. Evaluation of native microbial soil populations at a trichloroethylene contaminated Superfund site in the presence of a permeable reactive barrier (biowall) using a metagenomics approach

    Science.gov (United States)

    The Beaverdam Road Landfill occupies 3.5 acres and was an active disposal site for miscellaneous non-hazardous waste from 1943 to 1990, before being capped. In 1994, this site was included on the Nation Priorities List (NPL) for periodic inspection and remediation in accordance with the program regu...

  16. Dinucleotide repeat microsatellite markers for buck's-horn plantain (Plantago coronopus)

    NARCIS (Netherlands)

    Koorevaar, G.N.; Ivanovic, S.; Van Damme, J.M.M.; Koelewijn, H.P.; Van 't Westende, W.P.C.; Smulders, M.J.M.; Vosman, B.

    2002-01-01

    Eleven polymorphic microsatellite loci were obtained from a GA enriched genomic library, constructed from DNA of buck's-horn plantain (Plantago coronopus). The microsatellite loci were tested on 24 genotypes. These plants were collected from meadows along the coast, located on 11 sites ranging from

  17. Superfund record of decision (EPA Region 2): Malta Rocket Fuel Area Site, Towns of Malta and Stillwater, Saratoga County, NY, July 13, 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    This Record of Decision (ROD) documents the U.S. Environmental Protection Agency`s (EPA`s) selection of the remedial action for the Malta Rocket Fuel Area site (the Site). The remedy addresses the principal threats to human health and the environment that are posed by conditions at the Site. Exposure to soil contamination at the Malta Test Station will be addressed by excavation and off-site disposal of the contaminated soil. Ingestion of contaminated ground water by on-site employees will be addressed by pumping the Test Station water supply wells and treating the water to acceptable drinking water standards using an air stripper. Ground water not captured by the air stripper will be remediated to cleanup standards through natural attenuation and degradation processes.

  18. Transformer Isolated Buck-Boost Converters

    Directory of Open Access Journals (Sweden)

    Barry W. Williams

    2016-12-01

    Full Text Available Of the single-switch dc-to-dc converters, those with the buck-boost voltage transfer function offer most potential for transformer coupling, hence isolation, at the kilowatt level. This paper highlights the limitations of the traditional magnetic coupled, buck-boost topology. Then four split-capacitor transformer-coupled topologies (specifically the Cuk, sepic, zeta, and a new, converters with a common ac equivalent circuit are explored, that do not temporarily store core magnetic energy as does the traditional isolated buck-boost converter nor have a core dc magnetizing current bias, as with the sepic and zeta transformer coupled topologies. Core dc bias capacitive voltage compensation is a practical design constraint in three of the four topologies, while all four must cater for stray and leakage inductance effects. Simulations and experimental results for the new converter at 408W support the transformer-coupled, single-switch dc-to-dc converter concepts investigated.

  19. SPECTRAL ANALYSIS OF BUCK AND SEPIC CONVERTERS

    Directory of Open Access Journals (Sweden)

    CHAKIB ALAOUI

    2011-02-01

    Full Text Available Switched mode power converters generate harmonic currents, which will be injected into the utility grid, causing distortion of the utility waveform. They also become a source for the generation of EMI, which may affect the communication systems. This work is about the design and evaluation of the two most frequently used SMPS used in step down mode of operation: the Buck converter and the Sepic converter working in step-down mode of operation. These converters were designed using optimized equations for their components ratings. Simulation results show that although the Buck output voltage is low in harmonics, it has high harmonic contents in currents circulating in its inductor and diode, and hence requires strong filtering. The Sepic converterhas lower harmonic contents than the Buck converter.

  20. Effects of changes in pumping on regional groundwater-flow paths, 2005 and 2010, and areas contributing recharge to discharging wells, 1990–2010, in the vicinity of North Penn Area 7 Superfund site, Montgomery County, Pennsylvania

    Science.gov (United States)

    Senior, Lisa A.; Goode, Daniel J.

    2017-06-06

    A previously developed regional groundwater flow model was used to simulate the effects of changes in pumping rates on groundwater-flow paths and extent of recharge discharging to wells for a contaminated fractured bedrock aquifer in southeastern Pennsylvania. Groundwater in the vicinity of the North Penn Area 7 Superfund site, Montgomery County, Pennsylvania, was found to be contaminated with organic compounds, such as trichloroethylene (TCE), in 1979. At the time contamination was discovered, groundwater from the underlying fractured bedrock (shale) aquifer was the main source of supply for public drinking water and industrial use. As part of technical support to the U.S. Environmental Protection Agency (EPA) during the Remedial Investigation of the North Penn Area 7 Superfund site from 2000 to 2005, the U.S. Geological Survey (USGS) developed a model of regional groundwater flow to describe changes in groundwater flow and contaminant directions as a result of changes in pumping. Subsequently, large decreases in TCE concentrations (as much as 400 micrograms per liter) were measured in groundwater samples collected by the EPA from selected wells in 2010 compared to 2005‒06 concentrations.To provide insight on the fate of potentially contaminated groundwater during the period of generally decreasing pumping rates from 1990 to 2010, steady-state simulations were run using the previously developed groundwater-flow model for two conditions prior to extensive remediation, 1990 and 2000, two conditions subsequent to some remediation 2005 and 2010, and a No Pumping case, representing pre-development or cessation of pumping conditions. The model was used to (1) quantify the amount of recharge, including potentially contaminated recharge from sources near the land surface, that discharged to wells or streams and (2) delineate the areas contributing recharge that discharged to wells or streams for the five conditions.In all simulations, groundwater divides differed from

  1. Region 9 Removal Sites 2012

    Data.gov (United States)

    U.S. Environmental Protection Agency — Point geospatial dataset representing locations of CERCLA (Superfund) Removal sites. CERCLA (Comprehensive Environmental Response, Compensation, and Liability Act)...

  2. AHR-related activities in a creosote-adapted population of adult atlantic killifish, Fundulus heteroclitus, two decades post-EPA superfund status at the Atlantic Wood Site, Portsmouth, VA USA

    Energy Technology Data Exchange (ETDEWEB)

    Wojdylo, Josephine V. [Department of Biological Sciences, Environmental Toxicology Graduate Program, Clemson University, Clemson, SC 29634 (United States); Vogelbein, Wolfgang [The College of William & Mary, Gloucester Point, VA 23062 (United States); Bain, Lisa J. [Department of Biological Sciences, Environmental Toxicology Graduate Program, Clemson University, Clemson, SC 29634 (United States); Rice, Charles D., E-mail: cdrice@clemson.edu [Department of Biological Sciences, Environmental Toxicology Graduate Program, Clemson University, Clemson, SC 29634 (United States)

    2016-08-15

    Highlights: • AHR-related activities in creosote-adapted adult killifish were examined. • Creosote-adapted adult killifish have elevated intestine CYP1A. • Creosote-adapted adult killifish have elevated liver COX2 mRNA expression. • Most creosote-adapted adult killifish have lesions varying in severity. • Liver lesions in creosote-adapted adult killifish express CYP1A and AHR2 proteins. - Abstract: Atlantic killifish, Fundulus heteroclitus, are adapted to creosote-based PAHs at the US EPA Superfund site known as Atlantic Wood (AW) on the southern branch of the Elizabeth River, VA USA. Subsequent to the discovery of the AW population in the early 1990s, these fish were shown to be recalcitrant to CYP1A induction by PAHs under experimental conditions, and even to the time of this study, killifish embryos collected from the AW site are resistant to developmental deformities typically associated with exposure to PAHs in reference fish. Historically, however, 90 +% of the adult killifish at this site have proliferative hepatic lesions including cancer of varying severity. Several PAHs at this site are known to be ligands for the aryl hydrocarbon receptor (AHR). In this study, AHR-related activities in AW fish collected between 2011 and 2013 were re-examined nearly 2 decades after first discovery. This study shows that CYP1A mRNA expression is three-fold higher in intestines of AW killifish compared to a reference population. Using immunohistochemistry, CYP1A staining in intestines was uniformly positive compared to negative staining in reference fish. Livers of AW killifish were examined by IHC to show that CYP1A and AHR2 protein expression reflect lesions-specific patterns, probably representing differences in intrinsic cellular physiology of the spectrum of proliferative lesions comprising the hepatocarcinogenic process. We also found that COX2 mRNA expression levels were higher in AW fish livers compared to those in the reference population, suggesting a

  3. Superfund record of decision (EPA Region 2): General Motors/Central Foundry Division Site, St. Lawrence County, Massena, NY. (Second remedial action), March 1992. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-31

    The 270-acre General Motors/Central Foundry Division site is an aluminum casting plant in Massena, St. Lawrence County, New York. From 1985 to 1989, General Motors investigations detected contamination in soil, sludge, debris, sediment, ground water and surface water. In 1988, an interim cap was placed over the industrial landfill. A 1990 ROD addressed most affected areas of the site, including the St. Lawrence River System sediments, contaminated ground water, soils on the facility and the St. Regis Mohawk Indian Reservation, and material at four lagoons and the North Disposal Area. The ROD provides the final remedy for the contaminated soil, sludge, debris, and groundwater at the East Disposal Area and the Industrial Lagoon. The primary contaminants of concern are VOCs, including TCE; and other organics, including PCBs, phenols, and PAHs. The selected remedial action for the site are included.

  4. Superfund explanation of significant difference for the record of decision (EPA Region 3): Fairchild, Intel, and Raytheon Sites, (Mew Study Area), Mountain View, CA, September 1990

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-02-01

    The purpose of the document is to explain the significant differences between the Record of Decision (ROD) signed by the U.S. Environmental Protection Agency (EPA) on June 9, 1989 (PB90-118225) and the remedy that will be implemented at the Middlefield/Ellis/Whisman Study Area (MEW Site). The document provides a brief background on the MEW Site, describes the change to the ROD that EPA is now making and explains the ways in which this change affects implementation of the remedy selected by EPA in June of 1989.

  5. 一种新型Buck-Boost变换器%A Novel Buck-Boost Converter

    Institute of Scientific and Technical Information of China (English)

    高飞; 蒋赢; 赵小妹; 潘俊民

    2010-01-01

    提出了一种新型Buck-Boost变换器,与传统的Buck-Boost变换器相比,该电路利用开关电容网络,能在相同的输入电压和开关管占空比情况下具有更好的降压效果.对该新型Buck-Boost变换器的工作原理进行了分析,并通过仿真和实验验证了该方案的可行性.实验表明,该新型Buck-Boost变换器能够实现较好的降压效果,输出效果良好.

  6. Superfund Record of Decision (EPA Region 2): General Motors/Central Foundry Division site, St. Lawrence County, Massena, NY. (First remedial action), December 1990

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-17

    The 270-acre General Motors/Central Foundry Division site is an active aluminum casting plant in Massena, St. Lawrence County, New York. The site overlies a surficial alluvial aquifer and is adjacent to wetlands, both of which have been contaminated. Additional onsite features of concern include the unlined North and East Disposal Areas and the Industrial Landfill, which contain contaminated soil, debris, sludge; four unlined Industrial Lagoons, which contain contaminated liquids, sludge, and soil; the rivers and creek which contains contaminated sediment; contaminated soil on the St. Regis Mohawk Reservation and on General Motors property; and contaminated associated wetlands. The Record of Decision (ROD) provides a final remedy for all site areas and media except the East Disposal Area and the Industrial Landfill, which will be addressed in a subsequent ROD. The primary contaminants of concern affecting the soil, sediment, sludge, debris, ground water, and surface water are PCBs, and to a much lesser degree, VOCs including TCE; and other organics including PAHs, and phenols. The selected remedial action for this site is included.

  7. Commencement Bay Nearshore/Tideflats Superfund Site, Tacoma, Washington Remedial Investigations. Evaluation of Alternative Dredging Methods and Equipment, Disposal Methods and Sites, and Site Control and Treatment Practices for Contaminated Sediments.

    Science.gov (United States)

    1985-06-01

    Material Disposal in the Ocean, John Wiley & Sons, Inc., New York, New York. Myers, A. C., 1979. "Summer and Winter Burrows of a Mantis Shrimp , Squilla...Deep water is any depth below the influence of storm waves, which will vary between sites. Theoretically, depths are unlimited, although in fact ...Swann, et. al., uses the term in a thermodynamic sense. He classifies the organic compounds by mobility class when in fact his classifica- tion

  8. Women in History--Pearl Buck: An Advocate for Women and Children

    Science.gov (United States)

    Watts, Lynette

    2008-01-01

    This article profiles Pearl Buck, an advocate for women's rights and minority children, an author of Chinese history, and a pioneer in many ways. Buck established the Welcome House in 1949 in order to help unadoptable children find families (Conn, 1996). In 1964, Buck founded the Pearl S. Buck Foundation, now Pearl S. Buck International, which…

  9. Women in History--Pearl Buck: An Advocate for Women and Children

    Science.gov (United States)

    Watts, Lynette

    2008-01-01

    This article profiles Pearl Buck, an advocate for women's rights and minority children, an author of Chinese history, and a pioneer in many ways. Buck established the Welcome House in 1949 in order to help unadoptable children find families (Conn, 1996). In 1964, Buck founded the Pearl S. Buck Foundation, now Pearl S. Buck International, which…

  10. CERCLIS (Superfund) ASCII Text Format - CPAD Database

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Comprehensive Environmental Response, Compensation and Liability Information System (CERCLIS) (Superfund) Public Access Database (CPAD) contains a selected set...

  11. Superfund record of decision (EPA Region 9): Carson River Mercury Site, operable unit 1, Lyon, Storey and Churchill County, NV, March 30, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-06-01

    The Record of Decision (ROD) presents the selected remedial action for Operable Unit 1 (OU-1) of the Carson River Mercury Site (CRMS) which is located in Lyon, Storey and Churchill Counties, Nevada. The selected remedy for the five residential yards is to excavate contaminated surface soil (estimated to go to a depth of approximately 2 feet below ground surface), dispose of the soil at the RCRA municipal landfill if the soils do not exceed the TCLP standards, and restore the excavated areas. If it is determined that all or part of the excavated soil exceeds the TCLP standards, then the excavated soil will either be treated and disposed of at a RCRA municipal landfill or disposed of at the RCRA hazardous waste landfill.

  12. Delineation of areas having elevated electrical conductivity, orientation and characterization of bedrock fractures, and occurrence of groundwater discharge to surface water at the U.S. Environmental Protection Agency Barite Hill/Nevada Goldfields Superfund site near McCormick, South Carolina

    Science.gov (United States)

    Chapman, Melinda J.; Huffman, Brad A.; McSwain, Kristen Bukowski

    2015-07-16

    During October 2012 through March 2013, the U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (EPA) Region 4, Superfund Section, conducted borehole geophysical logging, surface geophysical surveys, and water-quality profiling in selected wells and areas to characterize or delineate the extent of elevated subsurface electrical conductivity at the EPA Barite Hill/Nevada Goldfields Superfund site near McCormick, South Carolina. Elevated electrical conductivity measured at the site may be related to native rock materials, waste rock disposal areas used in past operations, and (or) groundwater having elevated dissolved solids (primarily metals and major ions) related to waste migration. Five shallow screened wells and four open-borehole bedrock wells were logged by using a suite of borehole tools, and downhole water-quality profiles were recorded in two additional wells. Well depths ranged from about 26 to 300 feet below land surface. Surface geophysical surveys based on frequency-domain electromagnetic and distributed temperature sensing (DTS) techniques were used to identify areas of elevated electrical conductivity (Earth materials and groundwater) and potential high dissolved solids in groundwater and surface water on land and in areas along the northern unnamed tributary at the site.

  13. Earthworm survival and behavior results from a Clark Fork River Superfund site: Grant-Kohrs Ranch N.H.S., Montana

    Energy Technology Data Exchange (ETDEWEB)

    Rader, B.R.; Nimmo, D.R.; Chapman, P.L. [Colorado State Univ., Fort Collins, CO (United States)

    1995-12-31

    Concentrations of heavy metals in sediments and soils deposited along the floodplain of the Clark Fork River, within the boundaries of the Grant-Kohrs Ranch National Historic Site, have exceeded those typically found in uncontaminated soils. Upstream mining activities along the Clark Fork River in the Deer Lodge Valley, Montana, have produced substantial quantities of mine waste which have been deposited throughout the watershed. Releases and re-releases of these contaminated substances continue to occur, and appear to be preventing the germination and establishment of critical riparian plant species and depressing soil microbe activity. Slickens, bare spots devoid of all vegetation, occur frequently in the floodplain along the Clark Fork River. This research investigates the toxicity of slicken soils using a series of earthworm (Eisenia foetida andrei) survival and behavior tests. In dilution tests, earthworm survival was reduced significantly in as little as 12.5% slicken soil. Results from earthworm behavior tests currently being conducted using non-lethal slicken soil dilutions will also be presented.

  14. Trophic transfer and effects of DDT in male hornyhead turbot (Pleuronichthys verticalis) from Palos Verdes Superfund site, CA (USA) and comparisons to field monitoring.

    Science.gov (United States)

    Crago, Jordan; Xu, Elvis Genbo; Kupsco, Allison; Jia, Fang; Mehinto, Alvine C; Lao, Wenjian; Maruya, Keith A; Gan, Jay; Schlenk, Daniel

    2016-06-01

    High concentrations of DDT and metabolites (ΣDDT) have been detected in sediment and the demersal flatfish hornyhead turbot (Pleuronichtys verticalis) collected from Palos Verdes (PV), California, USA, a site contaminated with over 100 metric tons of DDT throughout 1960s-70s. This study was conducted to assess the transfer of ΣDDT from PV-sediment into polychaetes (Neanthes arenaceodentata) and hornyhead turbot, and to investigate if the responses in turbots from two different laboratory exposures mimic those in turbots caught in PV (PV-turbot). Turbot fed PV-sediment-contaminated polychaete for 7 days had liver concentrations of ΣDDT similar to PV-turbot. After 28 days, ΣDDT also accumulated in livers of turbot gavaged with a ΣDDT mixture. In vitro cell bioassays indicated significant increases of 17β-estradiol equivalents (EEQ) in turbot bile extracts as compared to the control in the 7-day study. These responses corresponded to those measured in PV-fish. Glucocorticoid receptor (GR), anti-androgen receptor (anti-AR), estrogen receptor (ER) or aryl hydrocarbon receptor (AhR) activities were also observed in extracts of PV-sediment, and PV-sediment-exposed worm. Anti-AR, AhR and GR activities were significantly higher in PV-sediment than reference sediment (San Diego, SD). Higher transcripts of hepatic VTG, ERα and ERβ were found in PV-turbot than SD-turbot, but were unaltered in fish exposed to sediment-contaminated worms for the 7-day study. In contrast, liver extracts from the 28-day treatment of ΣDDT showed lower EEQ but similar hepatic VTG and ERβ transcripts relative to those of PV-turbot. These data indicated that trophic transfer of sediment-associated DDT in 7-day exposures corresponded to field measurements of DDT residues and in vitro ER bioactivities, but failed to mimic in vivo biological effects observed in field fish. In contrast, treatment with ΣDDT alone for 28 days mimicked in vivo biological effects of DDTs in PV fish, but did not

  15. Site Area Boundaries

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset consists of site boundaries from multiple Superfund sites in U.S. EPA Region 8. These data were acquired from multiple sources at different times and...

  16. Site Area Boundaries

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset consists of site boundaries from multiple Superfund sites in U.S. EPA Region 8. These data were acquired from multiple sources at different times and...

  17. 一种新颖的Buck-Boost变换器%A Novel Buck-Boost Converter

    Institute of Scientific and Technical Information of China (English)

    方宇; 谢勇; 邢岩

    2003-01-01

    提出了一种新颖的两开关电路拓扑,它能工作在宽输入交流电压范围,并实现功率因数校正(PFC).新拓扑与单开关Buck-Boost变换器和传统的两开关串级Buck-Boost变换器及其它Buck-Boost变换器相比有显著的性能改善,如:器件应力及损耗较低,不需要解决浪涌电流问题,电感尺寸也较小.分析了拓扑工作原理,并给出了实验结果.

  18. Remediation System Evaluation, FCX Statesville Superfund Site

    Science.gov (United States)

    The FCX property was an agriculture distribution center that formulated, repackaged, and warehoused pesticides and fertilizers. The former Burlington Industries property to the north and upgradient of the FCX property was a textile facility.

  19. Superfund record of decision (EPA Region 5): Ormet Corporation, Hannibal, OH, September 1994

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-12

    The Record of Decision presents the selected remedy for the Ormet Corporation Superfund Site. The purpose of this remedy is to eliminate or reduce contamination in soils, sediments and ground water, and to reduce the risks associated with exposure to contaminated materials. This is the first and final remedy planned for the Site.

  20. Diode-Assisted Buck-Boost Voltage-Source Inverters

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Teodorescu, Remus;

    2009-01-01

    This paper proposes a number of diode-assisted buck-boost voltage-source inverters with a unique X-shaped diode-capacitor network inserted between the inverter circuitry and dc source for producing a voltage gain that is comparatively higher than those of other buck-boost conversion techniques...

  1. 36 CFR 7.73 - Buck Island Reef National Monument.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Buck Island Reef National Monument. 7.73 Section 7.73 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.73 Buck Island Reef National Monument...

  2. Controlled doe exposure as biostimulation of buck rabbits.

    Science.gov (United States)

    Rodríguez-De Lara, R; Noguez-Estrada, J; Rangel-Santos, R; García-Muñiz, J G; Martínez-Hernández, P A; Fallas-López, M; Maldonado-Siman, E

    2010-12-01

    Female exposure of males could be a low-cost biostimulation option that benefits AI in commercial rabbit operations by improving buck rabbits reproductive performance. The objective of the study was to evaluate exposure of buck rabbits to females as a biostimulation option to improve reproductive potential. Treatments were: exposure (biostimulated) or not (control) of bucks to does. Bucks were New Zealand White, 15-month-old, sexually experienced and fertile. Experimental design was completely random with nine replications, experimental unit was one buck. Doe exposure was permanent using replacement pubertal does housed in an adjacent wire-mesh cage and changed for new ones every other week. Semen collection lasted 14 weeks (late winter and early spring) twice a week with two ejaculates at each collection. Analyses of variance were under a mixed model: treatments, ejaculate number and season were fixed and rabbit random effects and buck weight at each collection as covariable. Biostimulated bucks showed greater (Pbucks but not in doe exposed bucks (treatment × ejaculate number, Pbuck rabbits. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. Effects of a remedial system and its operation on volatile organic compound-contaminated ground water, Operable Unit 1, Savage Municipal Well Superfund Site, Milford, New Hampshire, 1998-2004

    Science.gov (United States)

    Harte, Philip T.

    2006-01-01

    The Savage Municipal Well Superfund site in the Town of Milford, N.H., is underlain by a 0.5-square mile plume of volatile organic compounds (VOCs), mostly tetrachloroethylene (PCE). The plume occurs mostly within a highly transmissive sand and gravel layer, but also extends into underlying till and bedrock. The plume has been divided into two areas called Operable Unit 1 (OU1), which contains the primary source area, and Operable Unit 2 (OU2), which is defined as the extended plume area. PCE concentrations in excess of 100,000 parts per billion (ppb) had been detected in the OU1 area in 1995, indicating a likely Dense Non-Aqueous Phase Liquid (DNAPL) source. In the fall of 1998, the New Hampshire Department of Environmental Services (NHDES) and the U.S. Environmental Protection Agency (USEPA) installed a remedial system in OU1 to contain and capture the dissolved VOC plume. The OU1 remedial system includes a low-permeability barrier wall that encircles the highest detected concentrations of PCE, and a series of injection and extraction wells to contain and remove contaminants. The barrier wall likely penetrates the full thickness of the sand and gravel; in most places, it also penetrates the full thickness of the underlying basal till and sits atop bedrock. Remedial injection and extraction wells have been operating since the spring of 1999 and include a series of interior (inside the barrier wall) injection and extractions wells and exterior (outside the barrier wall) injection and extraction wells. A recharge gallery outside the barrier wall receives the bulk of the treated water and reinjects it into the shallow aquifer. From 1998 to 2004, PCE concentrations decreased by an average of 80 percent at most wells outside the barrier wall. This decrease indicates (1) the barrier wall and interior extraction effectively contained high PCE concentrations inside the wall, (2) other sources of PCE did not appear to be outside of the wall, and (3) ambient ground

  4. How stem defects affect the capability of optimum bucking method?

    Directory of Open Access Journals (Sweden)

    Abdullah Emin Akay

    2015-07-01

    Full Text Available In forest harvesting activities, computer-assisted optimum bucking method increases the economic value of harvested trees. The bucking decision highly depends on the log quality grades which mainly vary with the surface characteristics such as stem defects and form of the stems. In this study, the effects of stem defects on optimum bucking method was investigated by comparing bucking applications which were conducted during the logging operations in two different Brutian Pine (Pinus brutia Ten stands. In the applications, the first stand contained the stems with relatively more stem defects than that of the stems in the second stand. The average number of defects per log for sample trees in the first and the second stand was recorded as 3.64 and 2.70, respectively. The results indicated that optimum bucking method increased the average economic value of harvested trees by 15.45% and 8.26 % in the stands, respectively. Therefore, the computer-assisted optimum bucking method potentially provides better results than that of traditional bucking method especially for the harvested trees with more stem defects.

  5. Superfund: Interagency Agreements and Improved Project Management Needed to Achieve Cleanup Progress at Key Defense Installations

    Science.gov (United States)

    2010-07-01

    Superfund completing the remedial investigation, which would include a human and ecological risk assessment , feasibility study, proposed plan...EPA said that a human and ecological risk assessment —which would estimate how threatening a hazardous waste site is to human health and the

  6. Grain Handling Facility at Freeman, Washington Added to Superfund Cleanup List

    Science.gov (United States)

    (September 28, 2015 - Seattle) The U.S. Environmental Protection Agency has added the Grain Handling Facility at Freeman, in Spokane County, Washington, to the Superfund National Priorities List. The site was added to the NPL after EPA considered input rec

  7. Design and Control for the Buck-Boost Converter Combining 1-Plus-D Converter and Synchronous Rectified Buck Converters

    OpenAIRE

    2015-01-01

    In this paper, a design and control for the buck-boost converter, i.e., 1-plus-D converter with a positive output voltage, is presented, which combines the 1-plus-D converter and the synchronous rectified (SR) buck converter. By doing so, the problem in voltage bucking of the 1-plus-D converter can be solved, thereby increasing the application capability of the 1-plus-D converter. Since such a converter operates in continuous conduction mode inherently, it possesses the nonpulsating output cu...

  8. Testicular Morphometry and Sperm Quality of Rabbit Bucks Fed ...

    African Journals Online (AJOL)

    Testicular Morphometry and Sperm Quality of Rabbit Bucks Fed Graded Levels ... for their nutritional and medicinal values and are rich in minerals and vitamins. ... used to evaluate the effect of Moringa oleifera leaf meal (MOLM) on testicular ...

  9. Solid state light source driver establishing buck or boost operation

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, Fred

    2017-08-29

    A solid state light source driver circuit that operates in either a buck convertor or a boost convertor configuration is provided. The driver circuit includes a controller, a boost switch circuit and a buck switch circuit, each coupled to the controller, and a feedback circuit, coupled to the light source. The feedback circuit provides feedback to the controller, representing a DC output of the driver circuit. The controller controls the boost switch circuit and the buck switch circuit in response to the feedback signal, to regulate current to the light source. The controller places the driver circuit in its boost converter configuration when the DC output is less than a rectified AC voltage coupled to the driver circuit at an input node. The controller places the driver circuit in its buck converter configuration when the DC output is greater than the rectified AC voltage at the input node.

  10. Instantaneous Current Feedback Control Strategy on Buck Mode Inverter

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Control strategies for Buck mode inverter have important effect on static and dynamic characteristics, reliability, load capacity, and short-circuit resistance. Instantaneous current feedback control strategies include instantaneous inductor current feedback control and instantaneous capacitor current feedback control, both of which have essential difference. When the Buck mode inverter respectively adopts instantaneous inductor current and capacitor current feedback control strategies, characteristics of stability, output voltage and power, short circuit, nonlinear load and dynamic are fully investigated in this paper.

  11. Field Plot Points for Buck Island Reef National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This shapefile represents all the field plots visited on Buck Island. To fully comprehend this feature class, please refer to the full "Buck Island Reef National...

  12. SITE TECHNOLOGY CAPSULE: TEXACO GASIFICATION PROCESS

    Science.gov (United States)

    In 1980, the U.S. Congress passed the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), also known as Superfund. to protect human health and the environment from uncontrolled hazardous waste sites. CERCLA was amended by the Superfund Amendments and R...

  13. Series-Connected Buck Boost Regulators

    Science.gov (United States)

    Birchenough, Arthur G.

    2005-01-01

    A series-connected buck boost regulator (SCBBR) is an electronic circuit that bucks a power-supply voltage to a lower regulated value or boosts it to a higher regulated value. The concept of the SCBBR is a generalization of the concept of the SCBR, which was reported in "Series-Connected Boost Regulators" (LEW-15918), NASA Tech Briefs, Vol. 23, No. 7 (July 1997), page 42. Relative to prior DC-voltage-regulator concepts, the SCBBR concept can yield significant reductions in weight and increases in power-conversion efficiency in many applications in which input/output voltage ratios are relatively small and isolation is not required, as solar-array regulation or battery charging with DC-bus regulation. Usually, a DC voltage regulator is designed to include a DC-to-DC converter to reduce its power loss, size, and weight. Advances in components, increases in operating frequencies, and improved circuit topologies have led to continual increases in efficiency and/or decreases in the sizes and weights of DC voltage regulators. The primary source of inefficiency in the DC-to-DC converter portion of a voltage regulator is the conduction loss and, especially at high frequencies, the switching loss. Although improved components and topology can reduce the switching loss, the reduction is limited by the fact that the converter generally switches all the power being regulated. Like the SCBR concept, the SCBBR concept involves a circuit configuration in which only a fraction of the power is switched, so that the switching loss is reduced by an amount that is largely independent of the specific components and circuit topology used. In an SCBBR, the amount of power switched by the DC-to-DC converter is only the amount needed to make up the difference between the input and output bus voltage. The remaining majority of the power passes through the converter without being switched. The weight and power loss of a DC-to-DC converter are determined primarily by the amount of power

  14. Design and Control for the Buck-Boost Converter Combining 1-Plus-D Converter and Synchronous Rectified Buck Converters

    Directory of Open Access Journals (Sweden)

    Jeevan Naik

    2015-06-01

    Full Text Available In this paper, a design and control for the buck-boost converter, i.e., 1-plus-D converter with a positive output voltage, is presented, which combines the 1-plus-D converter and the synchronous rectified (SR buck converter. By doing so, the problem in voltage bucking of the 1-plus-D converter can be solved, thereby increasing the application capability of the 1-plus-D converter. Since such a converter operates in continuous conduction mode inherently, it possesses the nonpulsating output current, thereby not only decreasing the current stress on the output capacitor but also reducing the output voltage ripple. Above all, both the 1-plus-D converter and the SR buck converter, combined into a buck–boost converter with no right-half plane zero, use the same power switches, thereby causing the required circuit to be compact and the corresponding cost to be down. Furthermore, during the magnetization period, the input voltage of the 1-plus-D converter comes from the input voltage source, whereas during the demagnetization period, the input voltage of the 1-plus-D converter comes from the output voltage of the SR buck converter.

  15. INDUST.SUPERFUND_POLY_09

    Data.gov (United States)

    U.S. Environmental Protection Agency — This polygon layer represents a current (as of April 2009) list of CERCLIS' sites in EPA Region 7. Some of the sites are expanded to include plumes and others not.

  16. Computer simulations of optimum boost and buck-boost converters

    Science.gov (United States)

    Rahman, S.

    1982-01-01

    The development of mathematicl models suitable for minimum weight boost and buck-boost converter designs are presented. The facility of an augumented Lagrangian (ALAG) multiplier-based nonlinear programming technique is demonstrated for minimum weight design optimizations of boost and buck-boost power converters. ALAG-based computer simulation results for those two minimum weight designs are discussed. Certain important features of ALAG are presented in the framework of a comprehensive design example for boost and buck-boost power converter design optimization. The study provides refreshing design insight of power converters and presents such information as weight annd loss profiles of various semiconductor components and magnetics as a function of the switching frequency.

  17. Computer simulations of optimum boost and buck-boost converters

    Science.gov (United States)

    Rahman, S.

    1982-09-01

    The development of mathematicl models suitable for minimum weight boost and buck-boost converter designs are presented. The facility of an augumented Lagrangian (ALAG) multiplier-based nonlinear programming technique is demonstrated for minimum weight design optimizations of boost and buck-boost power converters. ALAG-based computer simulation results for those two minimum weight designs are discussed. Certain important features of ALAG are presented in the framework of a comprehensive design example for boost and buck-boost power converter design optimization. The study provides refreshing design insight of power converters and presents such information as weight annd loss profiles of various semiconductor components and magnetics as a function of the switching frequency.

  18. Component-Minimized Buck-Boost Voltage Source Inverters

    DEFF Research Database (Denmark)

    Gao, F.; Loh, P.C.; Blaabjerg, Frede;

    2007-01-01

    the additional voltage relationship between dc input and ac output which is beyond the expectation when continuous inductor current is assumed. These theoretical findings, together with the inverter practicality, have been confirmed in Matlab/PLECS simulations and  experimentally using laboratory implemented......This paper presents the design of buck-boost B4 inverters that can be derived from either Ćuk- or SEPIC-derived buck-boost B6 inverters. Unlike traditional inverters, the integration of front-end voltage boost circuitry and inverter circuitry allows it to perform buck-boost voltage inversion....... In order to form a distinct neutral potential in the corresponding voltage boost circuitry for correct B4 inverter operation, necessary modifications are derived step by step. The resulted dc networks with symmetrical placement of passive components allow complete charging and equal energy distribution...

  19. Accurate Sliding-Mode Control System Modeling for Buck Converters

    DEFF Research Database (Denmark)

    Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.

    2007-01-01

    This paper shows that classical sliding mode theory fails to correctly predict the output impedance of the highly useful sliding mode PID compensated buck converter. The reason for this is identified as the assumption of the sliding variable being held at zero during sliding mode, effectively mod...... approach also predicts the self-oscillating switching action of the sliding-mode control system correctly. Analytical findings are verified by simulation as well as experimentally in a 10-30V/3A buck converter.......This paper shows that classical sliding mode theory fails to correctly predict the output impedance of the highly useful sliding mode PID compensated buck converter. The reason for this is identified as the assumption of the sliding variable being held at zero during sliding mode, effectively...

  20. Solar Photovoltaic Powered Sailing Boat Using Buck Converter

    Directory of Open Access Journals (Sweden)

    Soumya Das

    2015-03-01

    Full Text Available The main objective of this paper is to establish technical and economical aspects of the application of stand-alone photovoltaic (PV system in sailing boat using a buck converter in order to enhance the power generation and also to minimize the cost. Performance and control of dc-dc converter, suitable for photovoltaic (PV applications, is presented here. A buck converter is employed here which extracts complete power from the PV source and feeds into the dc load. The power, which is fed into the load, is sufficient to drive a boat . With the help of matlab simulink software PV module and buck model has been designed and simulated and also compared with theoretical predictions.

  1. Accurate Modeling of Buck Converters with Magnetic-Core Inductors

    DEFF Research Database (Denmark)

    Astorino, Antonio; Antonini, Giulio; Swaminathan, Madhavan

    2015-01-01

    In this paper, a modeling approach for buck converters with magnetic-core inductors is presented. Due to the high nonlinearity of magnetic materials, the frequency domain analysis of such circuits is not suitable for an accurate description of their behaviour. Hence, in this work, a timedomain...... model of buck converters with magnetic-core inductors in a SimulinkR environment is proposed. As an example, the presented approach is used to simulate an eight-phase buck converter. The simulation results show that an unexpected system behaviour in terms of current ripple amplitude needs the inductor core...

  2. 77 FR 4559 - Ecusta Mill Site, Pisgah Forest, Transylvania County, NC; Notice of Amended Settlement

    Science.gov (United States)

    2012-01-30

    ... AGENCY Ecusta Mill Site, Pisgah Forest, Transylvania County, NC; Notice of Amended Settlement AGENCY... Ecusta Mill Superfund Site located in Pisgah Forest, Transylvania County, North Carolina. DATES: The... by Site name Ecusta Mill Superfund Site by one of the following methods:...

  3. Buck-boost converter feedback controller design via evolutionary search

    Science.gov (United States)

    Sundareswaran, K.; Devi, V.; Nadeem, S. K.; Sreedevi, V. T.; Palani, S.

    2010-11-01

    Buck-boost converters are switched power converters. The model of the converter system varies from the ON state to the OFF state and hence traditional methods of controller design based on approximate transfer function models do not yield good dynamic response at different operating points of the converter system. This article attempts to design a feedback controller for a buck-boost type dc-dc converter using a genetic algorithm. The feedback controller design is perceived as an optimisation problem and a robust controller is estimated through an evolutionary search. Extensive simulation and experimental results provided in the article show the effectiveness of the new approach.

  4. Diode-Assisted Buck-Boost Current Source Inverters

    DEFF Research Database (Denmark)

    Gao, F.; Cai, Liang; Loh, P.C.

    2007-01-01

    This paper presents a couple of novel current source inverters (CSIs) with the enhanced current buckboost capability. With the unique diode-inductor network added between current source inverter circuitry and current boost elements, the proposed buck-boost current source inverters demonstrate...... a double current boost capability when comparing with the recently reported buckboost CSIs. For modulating the presented CSIs, two modulation schemes are proposed for achieving either optimized harmonic performance or minimal commutation count, meanwhile keeping the important current buck-boost operation...

  5. The Simulation Research of Buck-Boost Converter%Buck-Boost变化器的仿真分析

    Institute of Scientific and Technical Information of China (English)

    李雪莉

    2010-01-01

    PSpice是一款功能强大的电路仿真软件,仿真结果十分接近电路的真实状态.应用PSpice对Buck-Boost变换器的全部工作过程进行了仿真与分析,Buck-Boost电路的工作过程包括电路启动时的瞬态工作过程和稳态工作过程.对电路中储能元件的各种工作状态进行了分析,给出了大量直观的仿真波形,从而更进一步了解了Buck-Boost变换器.

  6. Aquifer tests and simulation of ground-water flow in Triassic sedimentary rocks near Colmar, Bucks and Montgomery Counties, Pennsylvania

    Science.gov (United States)

    Risser, Dennis W.; Bird, Philip H.

    2003-01-01

    This report presents the results of a study by the U.S. Geological Survey in cooperation with the U.S. Environmental Protection Agency to evaluate ground-water flow in Triassic sedimentary rocks near Colmar, in Bucks and Montgomery Counties, Pa. The study was conducted to help the U.S. Environmental Protection Agency evaluate remediation alternatives at the North Penn Area 5 Superfund Site near Colmar, where ground water has been contaminated by volatile organic solvents (primarily trichloroethene). The investigation focused on determining the (1) drawdown caused by separately pumping North PennWater Authority wells NP?21 and NP?87, (2) probable paths of groundwater movement under present-day (2000) conditions (with NP?21 discontinued), and (3) areas contributing recharge to wells if pumping from wells NP-21 or NP?87 were restarted and new recovery wells were installed. Drawdown was calculated from water levels measured in observation wells during aquifer tests of NP?21 and NP?87. The direction of ground-water flow was estimated by use of a three-dimensional ground-water-flow model. Aquifer tests were conducted by pumping NP?21 for about 7 days at 257 gallons per minute in June 2000 and NP?87 for 3 days at 402 gallons per minute in May 2002. Drawdown was measured in 45 observation wells during the NP?21 test and 35 observation wells during the NP?87 test. Drawdown in observation wells ranged from 0 to 6.8 feet at the end of the NP?21 test and 0.5 to 12 feet at the end of the NP?87 test. The aquifer tests showed that ground-water levels declined mostly in observation wells that were completed in the geologic units penetrated by the pumped wells. Because the geologic units dip about 27 degrees to the northwest, shallow wells up dip to the southeast of the pumped well showed a good hydraulic connection to the geologic units stressed by pumping. Most observation wells down dip from the pumping well penetrated units higher in the stratigraphic section that were not well

  7. Environmental Asbestos Assessment Manual Superfund Method for the Determination of Asbestos in Ambient Air Part 2: Technical Background Document

    Science.gov (United States)

    A sampling and analysis method for the determination of asbestos in air is presented in Part 1 of this report, under separate cover. This method is designed specifically to provide results suitable for supporting risk assessments at Superfund sites, although it is applicable t...

  8. ASDTIC control and standardized interface circuits applied to buck, parallel and buck-boost dc to dc power converters

    Science.gov (United States)

    Schoenfeld, A. D.; Yu, Y.

    1973-01-01

    Versatile standardized pulse modulation nondissipatively regulated control signal processing circuits were applied to three most commonly used dc to dc power converter configurations: (1) the series switching buck-regulator, (2) the pulse modulated parallel inverter, and (3) the buck-boost converter. The unique control concept and the commonality of control functions for all switching regulators have resulted in improved static and dynamic performance and control circuit standardization. New power-circuit technology was also applied to enhance reliability and to achieve optimum weight and efficiency.

  9. Relationships between physiological and behavioral responses of goat bucks in mating season

    Directory of Open Access Journals (Sweden)

    Serhat Karaca

    Full Text Available ABSTRACT The objective of this study was to determine the sexual parameters in young bucks with different sexual activity and the effect of experience (age on sexual parameters in bucks. Fifteen young, sexually inexperienced (SI and five adult, sexually experienced (SE Saanen × Hair goat crossbred bucks were used in this study. Bucks were individually exposed to three estrus does for 15-min periods during four sexual performance tests, which were carried out every other day to determine some sexual behavior traits such as flehmen response, reaction time, and ejaculation efficiency. Sexually inexperienced young bucks were evaluated based on their sexual activity (active (AC vs inactive (IA and presence of horn. It was found that AC bucks had significantly higher serum testosterone concentrations (31.5 vs 21.5 ng/mL and weight loss (114.2 vs 51.2 g/day than IA bucks. In addition, weight loss was significantly correlated with ejaculation efficiency in young bucks. On the other hand, horned bucks tended to have higher ejaculation efficiency with significantly longer reaction time than polled bucks. For experience (age classes, SE bucks had higher testosterone concentration (76.0 vs 31.5 ng/mL and weight loss (16.7 vs 8.6% than SI active young bucks. However, the effect of experience on other sexual performance traits was found to be limited. Overall, these results indicate that testosterone concentration may affect sexual performance of young bucks in the mating season. Age-related sexual experience is not a determining factor for sexual performance in bucks. However, sexual performance data alone may not reflect reproductive outcomes without semen data.

  10. Integrated buck-boost converter with Matrix-POL architecture

    OpenAIRE

    2013-01-01

    In this study, integrated buck-boost converter with the Matrix-POL power supply system is proposed. From the simulation results, the validity of the Matrix-POL is revealed. The results revealed that the fast response to the load current and the voltage change can be done with duty and parallel number control by the proposed system.

  11. Two phase interleaved buck converter for driving high power LEDs

    DEFF Research Database (Denmark)

    Beczkowski, Szymon; Munk-Nielsen, Stig

    2011-01-01

    increases luminous efficacy of LED compared to PWM dimmed system. Because of the low dynamic resistance of LEDs the duty cycle of the converter does not change greatly with controlled current. By setting the input voltage of the buck converter to around twice the voltage of diode strings, converter can...

  12. Power decoupling method for single phase differential buck converter

    DEFF Research Database (Denmark)

    Yao, Wenli; Tang, Yi; Zhang, Xiaobin

    2015-01-01

    The well-known inherent second-order ripple power in single phase converters imposes harmonic stress on the dc link, resulting in low efficiency and overheating issues. In order to avoid installing bulky electrolytic capacitors or LC filters in the dc-link, this paper presents a differential buck...

  13. "The Bell Curve" and Carrie Buck: Eugenics Revisited.

    Science.gov (United States)

    Smith, J. David

    1995-01-01

    The 1994 publication of "The Bell Curve" by R. Herrnstein and C. Murray is compared to other examples of eugenic principles, including the sterilization of "feebleminded" Carrie Buck, family degeneracy studies focusing on lower class Caucasian families, and other works that view the poorest and least educated members of society…

  14. Eugenics Past and Present: Remembering Buck v. Bell.

    Science.gov (United States)

    Berson, Michael J.; Cruz, Barbara

    2001-01-01

    Provides background information about the eugenics movement. Focuses on eugenics in the United States detailing the case, Buck v. Bell, and eugenics in Germany. Explores the present eugenic movement, focusing on "The Bell Curve," China's one child policy, and the use of eugenic sterilizations in the United States and Canada. Includes…

  15. Reproductive Parameters of the West African Dwarf Bucks Raised in ...

    African Journals Online (AJOL)

    DR Ezihe

    2Department of Animal Production, University of Agriculture, Makurdi ... Thirty West African Dwarf (WAD) bucks were evaluated for reproductive ... human consumption in the third world. ... animals. Testicular size and scrotal circumference are closely related to each other ... separately using a ''Diamond MCT 500'' model.

  16. Superfund Training/Tech Transfer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This asset includes a collection of information resources, training, and other media related to hazardous waste site cleanup and characterization. A major part of...

  17. π型Buck-Boost交流变换器%π Type Buck-Boost AC/AC Converter

    Institute of Scientific and Technical Information of China (English)

    张友军; 翁振明; 王阿敏; 项家希

    2012-01-01

    提出一种对称结构π型Buck-Boost交流变换器及其变结构控制策略.该变换器由Buck交流单元和Boost交流单元组成,与级联式两级电路相比,省去前级LC输出滤波器,简化了电路结构.根据前、后单元的工作与否,π型交流变换器存在4种工作模式:Buck模式、Boost模式、直通模式和Buck -Boost模式.通过等效改变电路结构,变结构控制策略使得π型Buck-Boost交流变换器只有3种工作模式:Buck模式、Boost模式和直通模式.π型Buck -Boost交流变换器虽然具有两个独立的控制对象、采用两级占空比调制,但实际上最多只有一级功率变换,且存在直接功率传递通路,适用于稳压或调压应用场合.

  18. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: Facility Registry Services (FRS) : Toxic Release Inventory (TRI) , National Pollutant Discharge Elimination System (NPDES) , and Superfund Sites

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents the estimated density of georeferenced sites within individual, local NHDPlusV2 catchments and upstream, contributing watersheds based on the...

  19. Circuit Simulation for Solar Power Maximum Power Point Tracking with Different Buck-Boost Converter Topologies

    OpenAIRE

    2014-01-01

    The power converter is one of the essential elements for effective use of renewable power sources. This paper focuses on the development of a circuit simulation model for maximum power point tracking (MPPT) evaluation of solar power that involves using different buck-boost power converter topologies; including SEPIC, Zeta, and four-switch type buck-boost DC/DC converters. The circuit simulation model mainly includes three subsystems: a PV model; a buck-boost converter-based MPPT system; and ...

  20. EPA Region 2 SEMS_CERCLIS Sites All [R2] and SEMS_CERCLIS Sites NPL [R2] GIS Layers

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Region 2 SEMS_CERCLIS Sites All [R2] GIS layer contains unique Superfund Enterprise Management System (SEMS) site records. These records have the following...

  1. High Efficient Universal Buck Boost Solar Array Regulator SAR Module

    Science.gov (United States)

    Kimmelmann, Stefan; Knorr, Wolfgang

    2014-08-01

    The high efficient universal Buck Boost Solar Array Regulator (SAR) module concept is applicable for a wide range of input and output voltages. The single point failure tolerant SAR module contains 3 power converters for the transfer of the SAR power to the battery dominated power bus. The converters are operating parallel in a 2 out of 3 redundancy and are driven by two different controllers. The output power of one module can be adjusted up to 1KW depending on the requirements. The maximum power point tracker (MPPT) is placed on a separate small printed circuit board and can be used if no external tracker signal is delivered. Depending on the mode and load conditions an efficiency of more than 97% is achievable. The stable control performance is achieved by implementing the magnetic current sense detection. The sensed power coil current is used in Buck and Boost control mode.

  2. Closed Loop Control of Soft Switched Interleaved Buck Converter

    Directory of Open Access Journals (Sweden)

    R. Shenbagalakshmi

    2012-06-01

    Full Text Available Design, Modeling and Simulation of a closed loop control is presented for Interleaved Buck Converter with Soft Switching. The features of the closed loop system are to reduce the switching losses and load current sharing among the parallel connected converters. The control system of the converter is designed using PWM technique. In order to improve the transient response and dynamic stability of the converters, the controller parameters are designed based on current mode control. Resonant components thus designed enable the application of zero current switching for both the converters connected in parallel thereby maintaining greater efficiency and minimizing voltage and current oscillations. The system analysis, design and performance are verified through simulation using MATLAB/Simulink environment. The simulation approach reveals the high speed dynamic performance of the closed loop system designed using robust PID controller. The laboratory prototype of the Buck converter is developed to verify the controller platform using PIC16F877A microcontroller.

  3. Design & Implementation of Zero Voltage Switching Buck Converter

    Directory of Open Access Journals (Sweden)

    A.Suresh Kumar

    2014-09-01

    Full Text Available Zero voltage switching (ZVS buck converter is more preferable over hard switched buck converter for low power, high frequency DC-DC conversion applications. In Zero voltage switching converter, turn on & turn off of a switch occurs at zero voltage that results in lower switching losses. In this converter soft switching is achieved by using resonant components. The optimal values of resonant components are determined by using electric functions derived from circuit configuration. This type of soft switched resonant converter offers very low electromagnetic interference (EMI.This study presents the circuit configuration with least components to realize highly efficient zero voltage switching resonant converter. It’s feasibility is confirmed with the developed proto type model and experimental results are verified.

  4. Decentralized Interleaving of Paralleled Dc-Dc Buck Converters: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Brian B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rodriguez, Miguel [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-01

    We present a decentralized control strategy that yields switch interleaving among parallel connected dc-dc buck converters without communication. The proposed method is based on the digital implementation of the dynamics of a nonlinear oscillator circuit as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the pulse width modulation (PWM) carrier waveform. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work represents the first fully decentralized strategy for switch interleaving of paralleled dc-dc buck converters.

  5. Modeling and Simulation of Buck-Boost Converter with Voltage Feedback Control

    OpenAIRE

    2015-01-01

    In order to design the control system, it is necessary to have an exact model of buck-boost converter. This paper put forward the transfer function model of buck-boost converter by the state-space average method. The open-loop transfer function model of uncompensated system is deduced according to the mathematic model of the buck-boost converter, the controller is designed according to frequency domain. The phase and magnitude margin of the open-loop system of the buck-boost converter with co...

  6. Analysis of Non-minimum Phase in Buck-Boost Converter

    OpenAIRE

    2016-01-01

    In this paper, relations among the parameters of the non-minimum phase for the Buck-Boost converter are studied. It is demonstrated that when the Buck-Boost converter works in Buck mode, the negative regulation voltage is determined by the converter with the pre-designed inductor and load as the duty ratio D0.382, and the duty ratio has a limited effect on the negative regulation voltage of the converter; when the Buck-Boost converter works in Boost mode,the negative regulation voltage is det...

  7. Buck-Boost Current-Source Inverters With Diode-Inductor Network

    DEFF Research Database (Denmark)

    Gao, Feng; Liang, Chao; Loh, Poh Chiang

    2009-01-01

    This paper presents a number of novel currentsource inverters (CSIs) with enhanced current buck-boost capability. By adding a unique diode-inductor network between the inverter circuitry and current-boost elements, the proposed buck-boost CSIs demonstrate a doubling of current-boost capability......, as compared with other recently reported buck-boost CSIs. For controlling the proposed CSIs, two modulation schemes are designed for achieving either optimized harmonic performance or minimized commutation count without influencing the inverter current buck-boost gain. These theoretical findings were...

  8. 零纹波输入电流Buck-Boost变换器%Zero Rippled Input Current Buck-Boost Converter

    Institute of Scientific and Technical Information of China (English)

    陆治国; 林贤贞; 胡红琼; 邓文东

    2008-01-01

    针对传统Buck-Boost输入输出电流断续的缺点,提出一种基于独立电感零纹波输入电流和输出电流连续的Buck-Boost变换器,详细分析了变换器的稳态工作原理.采用状态空间平均法,建立了变换器动态小信号模型,给出了小信号特征Matlab仿真波形.并对其进行交错并联优化,最后Saber电路仿真证明了理论分析的正确性.

  9. EPA Removes Burrows Sanitation Site in Michigan from National List of Most Contaminated Sites

    Science.gov (United States)

    For Immediate Release No. 15-OPA142 CHICAGO - The U.S. Environmental Protection Agency today announced that the Burrows Sanitation Superfund site in Hartford Township, Van Buren County, Michigan, has been officially removed from the Agency's l

  10. Implementation of an ex situ stabilization technique at the Sand Springs superfund site to solidify and stabilize acid tar sludges involving a quick-lime based stabilization process and innovative equipment design

    Energy Technology Data Exchange (ETDEWEB)

    McManus, R.W. [SOUND Environmental Services, Inc., Dallas, TX (United States); Grajczak, P. [ARCO, Los Angeles, CA (United States); Wilcoxson, J.C. [ARCO, Plano, TX (United States); Webster, S.D. [Environmental Protection Agency, Dallas, TX (United States)

    1997-12-31

    An old refinery site was safely remediated a year before schedule and for 25% less than final engineering estimates for the stabilization remedy thanks to energetic project management and innovative design involving ex situ stabilization/solidification of acid tar sludges. A quicklime based process, Dispersion by Chemical Reaction (DCR{trademark}), was employed to solidify and stabilize (SS) over 103,000 cubic meters (135,000 cubic yards) of petroleum waste, mostly acidic tarry sludge. The SS process was selected over competing methods because it afforded minimal volume increase, could readily achieve Record of Decision (ROD) specified physical and chemical treatment goals, could be implemented with treatment equipment that minimized emissions, and could be performed with low reagent usage and at low cost. To ensure treatment goals were achieved and an accelerated schedule met, a custom designed and fabricated transportable treatment unit (TTU) was employed to implement the process. The treated material was visually soil-like in character, it was left in stockpiles for periods of time, and it was placed and compacted in the on site landfill using standard earth-moving equipment.

  11. Feasibility Study of Economics and Performance of Solar Photovoltaics at the Standard Chlorine of Delaware Superfund Site in Delaware City, Delaware. A Study Prepared in Partnership with the Environmental Protection Agency for the RE-Powering America's Land Initiative: Siting Renewable Energy on Potentially Contaminated Land and Mine Sites

    Energy Technology Data Exchange (ETDEWEB)

    Salasovich, J.; Geiger, J.; Mosey, G.; Healey, V.

    2013-06-01

    The U.S. Environmental Protection Agency (EPA), in accordance with the RE-Powering America's Land initiative, selected the Standard Chlorine of Delaware site in Delaware City, Delaware, for a feasibility study of renewable energy production. The National Renewable Energy Laboratory (NREL) provided technical assistance for this project. The purpose of this report is to assess the site for a possible photovoltaic (PV) system installation and estimate the cost, performance, and site impacts of different PV options. In addition, the report recommends financing options that could assist in the implementation of a PV system at the site.

  12. Hydrogeologic framework, hydrology, and refined conceptual model of groundwater flow for Coastal Plain aquifers at the Standard Chlorine of Delaware, Inc. Superfund Site, New Castle County, Delaware, 2005-12

    Science.gov (United States)

    Brayton, Michael J.; Cruz, Roberto M.; Myers, Luke; Degnan, James R.; Raffensperger, Jeff P.

    2015-01-01

    From 1966 to 2002, activities at the Standard Chlorine of Delaware chemical facility in New Castle County, Delaware resulted in the contamination of groundwater, soils, and wetland sediment. In 2005, the U.S. Geological Survey (USGS), in partnership with the U.S. Environmental Protection Agency, Region 3, and the Delaware Department of Natural Resources and Environmental Control began a multi-year investigation of the hydrogeologic framework and hydrology of the confined aquifer system. The goals of the ongoing study at the site (the Potomac Aquifer Study) are to determine the hydraulic connection between the Columbia and Potomac aquifers, determine the direction of groundwater flow in the Potomac aquifer, and identify factors affecting the fate of contaminated groundwater. This report describes progress made towards these goals based on available data collected through September 2012.

  13. Superfund record of decision (EPA Region 4): Helena Chemical Company, (Tampa Plant), Hillsborough County, Tampa, FL, May 7, 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    The decision document (Record of Decision), presents the selected remedial action for the Helena Chemical Company Superfund Site, Tampa, Hillsborough County, Florida. This action addresses soil, sediment, and ground water contamination at the site and calls for the implementation of response measures which will protect human health and the environment. The selected remedy includes biological treatment (i.e., bioremediation) of pesticides and other site related contaminants located in surface soil sand sediments to levels appropriate for future industrial use of the Site. In addition, the selected remedy includes ground water recovery and treatment to remove pesticides and other site related contaminants.

  14. Single phase AC-DC power factor corrected converter with high frequency isolation using buck converter

    Directory of Open Access Journals (Sweden)

    R. Ramesh,

    2014-03-01

    Full Text Available Single phase ac-dc converters having high frequency isolation are implemented in buck, boost, buck-boost configuration with improving the power quality in terms of reducing the harmonics of input current. The paperpropose the circuit configuration, control mechanism, and simulation result for the single phase ac-dc converter.

  15. 77 FR 12323 - Draft Environmental Impact Statement for the General Management Plan, Buck Island Reef National...

    Science.gov (United States)

    2012-02-29

    ... National Park Service Draft Environmental Impact Statement for the General Management Plan, Buck Island... Availability of a Draft Environmental Impact Statement for the General Management Plan (DEIS/GMP), Buck Island... alternatives for consideration, including a No-Action Alternative that continues current management policies...

  16. A Novel Quadratic Buck-Boost DC-DC Converter without Floating Gate-Driver

    DEFF Research Database (Denmark)

    Mostaan, Ali; A. Gorji, Saman; N. Soltani, Mohsen

    2016-01-01

    for floating gate driver. In addition, the voltage stress of one of the switches is lower than the existing quadratic buck-boost converters. Performance of the analytical results is validated using both simulation in MATLAB/SIMULINK and experimental tests where the proposed converter is evaluated in both buck...

  17. A Novel Quadratic Buck-Boost DC-DC Converter without Floating Gate-Driver

    DEFF Research Database (Denmark)

    Mostaan, Ali; A. Gorji, Saman; N. Soltani, Mohsen

    2016-01-01

    for floating gate driver. In addition, the voltage stress of one of the switches is lower than the existing quadratic buck-boost converters. Performance of the analytical results is validated using both simulation in MATLAB/SIMULINK and experimental tests where the proposed converter is evaluated in both buck...

  18. Biological Determinism and the Concept of Mental Retardation: The Lesson of Carrie Buck.

    Science.gov (United States)

    Smith, J. David

    This paper reviews the case of Carrie Buck, who was the first person sterilized (in 1927) under a Virginia law allowing sterilization of persons identified as incompetent and likely to genetically transmit physical, psychological, or social deficiencies to their offspring. This law was later upheld by the Supreme Court in Buck v. Bell, which…

  19. What is the Best Converter for Low Voltage Fuel Cell Applications- A Buck or Boost?

    DEFF Research Database (Denmark)

    Nymand, Morten; Tranberg, René; Madsen, Mark E.;

    2009-01-01

    Amongst many converter topologies that have been proposed and developed for low voltage fuel cell applications, isolated full-bridge Buck and Boost converters appear to be the most popular. Although the Buck topology is considered to be superior in performance, for particularly being more efficient....... Experimental results of two 1.5 kW prototype Buck and Boost converter units are presented with detailed discussions, and the paper explains why, in contrary to the popular belief, a properly designed Boost topology is superior in performance to Buck topology and more appropriate for low voltage fuel cell......, this claim has never been proved with a ‘proper’ comparison to the Boost topology. This paper presents a comprehensive comparison between Buck and Boost topologies, which are designed for the same specifications and tested under the same and stringent operating conditions using precision measuring equipment...

  20. What is the Best Converter for Low Voltage Fuel Cell Applications- A Buck or Boost?

    DEFF Research Database (Denmark)

    Nymand, Morten; Tranberg, René; Madsen, Mark E.

    2009-01-01

    Amongst many converter topologies that have been proposed and developed for low voltage fuel cell applications, isolated full-bridge Buck and Boost converters appear to be the most popular. Although the Buck topology is considered to be superior in performance, for particularly being more efficient......, this claim has never been proved with a ‘proper’ comparison to the Boost topology. This paper presents a comprehensive comparison between Buck and Boost topologies, which are designed for the same specifications and tested under the same and stringent operating conditions using precision measuring equipment....... Experimental results of two 1.5 kW prototype Buck and Boost converter units are presented with detailed discussions, and the paper explains why, in contrary to the popular belief, a properly designed Boost topology is superior in performance to Buck topology and more appropriate for low voltage fuel cell...

  1. Simulated Analysis of APFC for BUCK- BOOST Converter with Matlab%用Matlab实现BUCK-BOOST变换器 APFC的仿真分析

    Institute of Scientific and Technical Information of China (English)

    刘宇; 谢品芳; 周雒维

    2001-01-01

    本文分析了用BUCK-BOOST电路进行功率因素校正的原理和变换过程,给出了BUCK-BOOS电路的Matlab仿真分析的模型.通过对变换器工作在DCM模式下的电路仿真,验证了此方法具有良好的效果.

  2. EPA Proposes to Add Dutchess County Creek, N.Y. to the Federal Superfund List, Sediment Contaminated with Mercury, Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    (New York, N.Y.) The U.S. Environmental Protection Agency today proposed adding the Wappinger Creek in Dutchess County, N.Y. to its Superfund National Priorities List of the country's most hazardous waste sites. Sediment within the two mile long tidal port

  3. Nonlinear Phenomena in Buck-Boost Power Factor Correction Converter

    Directory of Open Access Journals (Sweden)

    Mehrnoosh Vatani

    2013-01-01

    Full Text Available Buck-Boost Power-Factor-Correction (PFC converter with Average-Current-Model (ACM control is a nonlinear circuit because of the multiplier using and large change in the duty cycle, so its stability analysis must be studied by nonlinear model. In this paper double averaging method is used for describing the model of this converter. By this model we would be able to explain the low frequency dynamics of the system and identify stability boundaries according to circuit parameters and also nonlinear phenomena of this converter are detected.

  4. Stability analysis of a buck regulator employing input filter compensation

    Science.gov (United States)

    Kelkar, S. S.; Lee, F. C.

    1983-01-01

    The interaction between the input filter and the regulator often causes serious degradation of performance. The reduction in loop gain due to input filter interaction can result in system instability. An exact stability analysis of the buck regulator system is presented. The input filter parameter values are varied and system instability is predicted for the case without feedforward. The eigenvalues of the system can be brought back into the unit circle and the system thus stabilized with the addition of the feedforward loop. Measurements made for the cases with and without feedforward confirm the analytical prediction.

  5. Stability Aspects in One-Cycle Controlled Buck Converters

    Directory of Open Access Journals (Sweden)

    GURBINA, M.

    2014-02-01

    Full Text Available The paper aims to investigate issues related to one cycle controlled buck converters stability, in the situation when the integration capacitor discharging is performed through a non-zero value resistor, as it happens in practice. It is known that in this case the exponential discharge makes capacitor voltage theoretically never reach zero. Under these conditions, instability phenomena are expected when the discharge time is short, that is at high duty cycles. The stability condition is analytically derived with respect to the control voltage. It is shown that instability occurs with period doubling leading to a half switching frequency subharmonic. Computer simulations confirm the validity of theoretical considerations.

  6. Protective role of glutathione in buck semen cryopreservation.

    Science.gov (United States)

    Noei Razliqi, R; Zhandi, M; Shakeri, M; Towhidi, A; Sharafi, M; Emamverdi, M; Khodaei Motlagh, M

    2015-01-01

    The aim of this study was to determine the effect of low levels of glutathione on post-thawed buck sperm quality. In this experiment, different concentrations of glutathione [0 (LG-0), 0.5 (LG-0.5), 1 (LG-1), 1.5 (LG-1.5), and 2 (LG-2) mM] were added in a soybean lecithin-based extender. A total of 16 ejaculates from four bucks were collected and pooled. Each pooled sample was divided into five equal parts and each part was diluted by one of the above mentioned groups. After freeze-thawing process, motility and velocity, plasma membrane integrity and functionality, and apoptosis features of spermatozoa were evaluated. The results of this experiment showed that total motility (50.75 ± 2.33), plasma membrane integrity (55.75 ± 3.01) and functionality (46.75 ± 2.79) were higher in LG-1 extender compared to other extenders (Pbuck sperm quality compared to other extenders.

  7. A TEG Efficiency Booster with Buck-Boost Conversion

    Science.gov (United States)

    Wu, Hongfei; Sun, Kai; Zhang, Junjun; Xing, Yan

    2013-07-01

    A thermoelectric generator (TEG) efficiency booster with buck-boost conversion and power management is proposed as a TEG battery power conditioner suitable for a wide TEG output voltage range. An inverse-coupled inductor is employed in the buck-boost converter, which is used to achieve smooth current with low ripple on both the TEG and battery sides. Furthermore, benefiting from the magnetic flux counteraction of the two windings on the coupled inductor, the core size and power losses of the filter inductor are reduced, which can achieve both high efficiency and high power density. A power management strategy is proposed for this power conditioning system, which involves maximum power point tracking (MPPT), battery voltage control, and battery current control. A control method is employed to ensure smooth switching among different working modes. A modified MPPT control algorithm with improved dynamic and steady-state characteristics is presented and applied to the TEG battery power conditioning system to maximize energy harvesting. A 500-W prototype has been built, and experimental tests carried out on it. The power efficiency of the prototype at full load is higher than 96%, and peak efficiency of 99% is attained.

  8. Seasonal variations of cauda epididymal spermatozoa of bucks

    Directory of Open Access Journals (Sweden)

    Dilip Kumar Swain

    2016-09-01

    Full Text Available Objective: The study was conducted to evaluate the influence of season on cauda epididymal spermatozoa isolated from bucks. Materials and methods: Testes of 30 mature bucks were collected from local slaughter house, and were processed for the retrieval of cauda epididymal spermatozoa for evaluation. Testes were collected in three seasons (winter, summer and rainy, and each season was having 10 pairs of testicles. Recovered spermatozoa from the cauda epididymis were processed immediately for evaluation of semen attributes (Spermatozoa motility, viability, plasma membrane integrity, acrosomal status and DNA integrity. Results: Physiological effect of season was observed on progressive motility, percent of live spermatozoa, spermatozoal membrane integrity (HOST, acrosomal integrity, capacitation status and DNA integrity. Progressive motility, percent live spermatozoa, HOST positive spermatozoa, were found significantly (P<0.05 high in summer season, whereas, significantly (P<0.05 lower comet positive spermatozoa were found in summer season as compared to rainy and winter. Compromised acrosomal status was seen in winter and rainy seasons as compared to summer. Conclusion: Compromised acrosome along with plasma membrane and higher percentage of spermatozoa with damaged DNA in cauda spermatozoa were observed during winter and rainy seasons as compared to summer season. Summer season was found to be the most suitable season for collection of cauda epididymal spermatozoa and can effectively be used for assisted reproduction with further investigations of associated mechanisms. [J Adv Vet Anim Res 2016; 3(3.000: 263-267

  9. Carson Lake Pasture : Mercury Superfund Site : Soil investigation

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The objective of this investigation is to determine whether the soil in the CLkP exceeds the EPA's hazardous waste level criterion for mercury and whether there is...

  10. BIOLOGICAL TREATMENT OF LEACHATE FROM A SUPERFUND SITE

    Science.gov (United States)

    Studies have heen completed on treating a leachate from New Lyme, Ohio. The leachate was transported to Cincinnati, Ohio, where a pilot-sized rotating biological contactor (RBC) was used for a treatment evaluation. he biomass was developed on the ARC discs with primary effluent f...

  11. A biological assessment of Wildcat Landfill Superfund Site

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document was prepared as part of the Wildcat Landfill Remedial Investigation (RI) Report; the report was financed through a grant and authority of CERCLA as...

  12. Optimization Review, Fairfield Coal Gasification Plant Superfund Site, Fairfield, Iowa

    Science.gov (United States)

    The Fairfield Coal Gasification Plant (FCGP) also known as the Fairfield Former Manufactured Gas Plant (MGP) is located in the southwest 1/4 of the southeast 1/4, Section 26, Township 72 North, Range 10 West of Jefferson County, Iowa.

  13. OLEM Center for Program Analysis Site Analysis Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — This asset includes environmental justice-related analyses of population located within a mile of Superfund and RCRA Corrective Action sites. It characterizes...

  14. Toxicity tests and sediment chemistry at Site 9 (Neptune Drive Disposal Site) - U.S. Naval Air Station, Brunswick, Maine

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — During a remedial investigation of the U.S. Naval Air Station Superfund Site in Brunswick, Maine (NASB), elevated concentrations of total polycyclic aromatic...

  15. AMCO Off-Site Air Monitoring Polygons, Oakland CA, 2017, US EPA Region 9

    Data.gov (United States)

    U.S. Environmental Protection Agency — This feature class was developed to support the AMCO Chemical Superfund Site air monitoring process and depicts a single polygon layer, Off-Site Air Monitors,...

  16. Cascaded Buck-Boost AC/AC converter%级联式Buck-Boost AC/AC变换器

    Institute of Scientific and Technical Information of China (English)

    张友军; 丁明昌; 任永保; 王阿敏; 翁振明

    2010-01-01

    详细分析了Buck型和Boost型AC/AC变换器的工作原理及其控制方法,在此基础上提出了一种新型级联式Buck-Boost AC/AC变换器及其三模式控制策略.三模式控制策略是比较输入电压与基准输出电压的大小,使得变换器只有3种工作模式:Buck模式、Boost模式和滤波模式.该电路虽然由Buck型和Boost型AC/AC变换器2级变换器级联而成,并采用2级占空比调制,但实际上最多只存在一级功率变换,具有控制简单、变换效率高、开关管电压应力低等优点.仿真结果证明了级联式Buck-Boost AC/AC变换器及其控制策略的可行性和理论分析的正确性.

  17. Modelling and Simulation of Variable Frequency Synchronous DC-DC Buck Converter

    Directory of Open Access Journals (Sweden)

    Jeya Selvan Renius

    2014-10-01

    Full Text Available In this paper, novel small-signal averaged models for dc–dc converter operating at variable switching frequency are derived. This is achieved by separately considering the on-time and the off-time of the switching period. The derivation is shown in detail for a synchronous buck converter. The Enhanced Small Signal (ESSA Model is derived for the synchronous buck converter. The equivalent series inductance (ESL is also considered in this modelling. The buck converter model is also simulated in MATLAB and the result is also presented.

  18. The Model and Quadratic Stability Problem of Buck Converter in DCM

    Directory of Open Access Journals (Sweden)

    Li Xiaojing

    2016-01-01

    Full Text Available Quadratic stability is an important performance for control systems. At first, the model of Buck Converter in DCM is built based on the theories of hybrid systems and switched linear systems primarily. Then quadratic stability of SLS and hybrid feedback switching rule are introduced. The problem of Buck Converter’s quadratic stability is researched afterwards. In the end, the simulation analysis and verification are provided. Both experimental verification and theoretical analysis results indicate that the output of Buck Converter in DCM has an excellent performance via quadratic stability control and switching rules.

  19. High Resolution Imagery of Buck Island Coral Reef Systems Prior to and During Suspected Bleaching Events

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is a collection of imagery of Buck Island coral reef systems. They are pairs of imagery where one image was acquired during a suspected bleaching event....

  20. Modeling and Simulation of Buck-Boost Converter with Voltage Feedback Control

    Directory of Open Access Journals (Sweden)

    Zhou Xuelian

    2015-01-01

    Full Text Available In order to design the control system, it is necessary to have an exact model of buck-boost converter. This paper put forward the transfer function model of buck-boost converter by the state-space average method. The open-loop transfer function model of uncompensated system is deduced according to the mathematic model of the buck-boost converter, the controller is designed according to frequency domain. The phase and magnitude margin of the open-loop system of the buck-boost converter with compensator have both been increased. After compensating, this control system has the advantages of small overshoot and short settling time. It can also improve control system’s real time property and anti-interference ability.

  1. Rich, Well-Educated Get Bigger Bang for Buck from Mediterranean Diet

    Science.gov (United States)

    ... Well-Educated Get Bigger Bang for Buck From Mediterranean Diet Researchers suspect food quality may account for ... 2017 TUESDAY, Aug. 1, 2017 (HealthDay News) -- The Mediterranean diet -- rich in fruits, vegetables, fish, olive oil, ...

  2. Backscatter 0.5m TIFF Mosaic of St. Croix (Buck Island), US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the north shore of Buck Island, St. Croix, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography...

  3. An Effective Wind Energy System based on Buck-boost Controller

    Directory of Open Access Journals (Sweden)

    N. Prakash

    2013-06-01

    Full Text Available In Domestic Wind Machines, if the wind speed is low, the output voltage is not sufficient to charge the battery as it is lower than the rated charging voltage of the battery. This limits the overall efficiency of the Wind Machine to 20%. This study proposed to design and develop a Buck Boost Controller for the effective utilization of the wind machine. By implementing a controller based Buck Boost converter, the voltage produced at the lower wind speeds can also be utilized effectively by boosting it to the rated charging voltage of the battery. Also if the wind speed is high (>14 m/s, the DC output voltage will increase to more than 65 V. The converter bucks this high voltage to the nominal battery charging voltage (52 V, thereby protecting the battery from over charging voltage. Thus the effective utilization of the wind machine has been achieved by the use of the proposed Buck Boost Controller.

  4. BUCK-BOOST变换器的输出能量分析及电感电容优化设计%Output Energy Analysis and Optimization Design of Inductance and Capacitance of BUCK-BOOST Converters

    Institute of Scientific and Technical Information of China (English)

    殷立; 王顺强

    2012-01-01

    The inner intrinsic safety of BUCK-BOOST convert is analyzed by minimum ignition curve. The worst-case energy of BUCK-BOOST is calculated. Comparing with the minimum ignition curve, the intrinsic safety of BUCK-BOOST convert is implemented. Through calculation, the maximum load capacitor and inductance are obtained.%从最小点燃曲线角度分析BUCK-BOOST变换器内部本质安全性能,推算出BUCK-BOOST最恶劣情况下的能量,与火花点燃曲线相比较,得到本安输出的BUCK-BOOST变换器,并通过计算得出最大负载电容及负载电感。

  5. Nonlinear program based optimization of boost and buck-boost converter designs

    Science.gov (United States)

    Rahman, S.; Lee, F. C.

    1981-01-01

    The facility of an Augmented Lagrangian (ALAG) multiplier based nonlinear programming technique is demonstrated for minimum-weight design optimizations of boost and buck-boost power converters. Certain important features of ALAG are presented in the framework of a comprehensive design example for buck-boost power converter design optimization. The study provides refreshing design insight of power converters and presents such information as weight and loss profiles of various semiconductor components and magnetics as a function of the switching frequency.

  6. Reliability-Oriented Design of LC Filter in Buck DC-DC Converter

    DEFF Research Database (Denmark)

    Liu, Yi; Huang, Meng; Wang, Huai;

    2015-01-01

    State-of-the-art LC filter design of buck DC-DC converter is based on the specifications of voltage and current ripples and constrains in power density and cost. Since lifetime is an important performance factor in reliability critical applications, this digest proposes a method to optimize...... an optimized LC filter design to fulfill the required lifetime. The theoretical analysis and simulation study are presented which are verified by the experimental results from a buck converter prototype....

  7. Acoustical Evaluation of Bucking Bars during Riveting Operations in Bldg 9001, Tinker AFB, Oklahoma

    Science.gov (United States)

    2013-11-14

    bar can be either a formed piece of metal used alone, see Figure 1, or the dolly portion of a dampened bucking bar, see Figure 2. c. Sample...bucking bars, 135 total rivets for each of the three processes. Dolly 4 Distribution A: Approved for public release; distribution is...Industrial Tool TP111R (handle) TP1510A ( dolly ) 4. RESULTS: Assessment data for all three processes are displayed in Figures 3, 4, and 5

  8. Superfund reform: US Environmental Protection Agency`s 30-day study and its implication for the US Department of Energy

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, M.R.; Friedman, J.R.; Neff, R.W.

    1993-03-01

    As part of an ongoing effort to reform and restructure the US Environmental Protection Agency`s (EPAS) Superfund program, the EPA Administrator on October 21, 1991, announced several key programmatic reforms. These reforms are a result of the Superfund 30-Day Task Force Report (30-Day Study, EPA 1991a), an effort carried out by EPAs office of Solid Waste and Emergency Response (OSWER). The EPA OSWER oversees environmental cleanup activities under a number of statutory authorities, including the Comprehensive Environmental response, Compensation, and Liability Act (CERCLA, also known as Superfund). CERCLA and its implementing regulation, the National Contingency Plan (NCP), establish a regulatory framework to govern the cleanup of existing, and often abandoned, hazardous waste sites. The purposes of this report are to (1) review the background and recommendations of EPNs 30-Day Study, (2) identify and discuss the initiatives from the 30-Day Study that may impact DOE`s environmental restoration mission, (3) report on EPAs progress in implementing the selected priority initiatives, and (4) describe potentially related DOE activities.

  9. Buck Converter with Soft-Switching Cells for PV Panel Applications

    Directory of Open Access Journals (Sweden)

    Cheng-Tao Tsai

    2016-03-01

    Full Text Available In power conversion of photovoltaic (PV energy, a hard-switching buck converter always generates some disadvantages. For example, serious electromagnetic interference (EMI, high switching losses, and stresses on an active switch (metal-oxide-semiconductor-field-effect-transistor, MOSFET, and high reverse-recovery losses of a freewheeling diode result in low conversion efficiency. To release these disadvantages, a buck converter with soft-switching cells for PV panel applications is proposed. To create zero-voltage-switching (ZVS features of the active switches, a simple active soft-switching cell with an inductor, a capacitor, and a MOSFET is incorporated into the proposed buck converter. Therefore, the switching losses and stresses of the active switches and EMI can be reduced significantly. To reduce reverse-recovery losses of a freewheeling diode, a simple passive soft-switching cell with a capacitor and two diodes is implemented. To verify the performance and the feasibility of the proposed buck converter with soft-switching cells for PV panel applications, a prototype soft-switching buck converter is built and implemented by using a maximum-power-point-tracking (MPPT method. Simulated and experimental results are presented from a 100 W soft-switching buck converter for PV panel applications.

  10. Smooth-Transition Simple Digital PWM Modulator for Four-Switch Buck-Boost Converters

    Science.gov (United States)

    Rodriguez, Alberto; Rodriguez, Miguel; Vazquez, Aitor; Maija, Pablo F.; Sebastian, Javier

    2014-08-01

    Four Switch non-inverting Buck-Boost (4SBB) converters are extensively used in non-isolated applications where voltage step-up and step-down are required. In order to achieve high efficiency operation it is preferred to control the 4SBB as a Buck or Boost converter, depending on the input/output voltage ratio. However, when input and output voltages are close this approach requires near- unity conversion ratios, which are difficult to achieve in practice. Several alternative operating modes have been proposed in the literature to overcome this issue. In particular, operating the 4SBB as a Buck and Boost at the same time (Buck+Boost mode) has proven to be adequate to achieve near-unity conversion ratios.This paper proposes a simple, hardware-efficient digital pulse width modulator for a 4SBB that enables operation in Buck, Boost and Buck+Boost modes, thus allowing near-unity conversion ratios, while achieving smooth transitions between the different modes. The proposed modulator is simulated with Simulink and experimentally demonstrated using a 500W 4SBB converter with 24V input voltage and 12V-36V output voltage range.

  11. 基于模糊PI的buck-boost变换器控制%Fuzzy PI Control for Buck-boost Converter

    Institute of Scientific and Technical Information of China (English)

    王磊

    2012-01-01

      For the strong nonlinearity of the DC/DC converter, this paper proposes a new fuzzy PI con⁃troller, which combines fuzzy control method with traditional PI dual loop control method. All the details about the fuzzy PI controller are provided, including the key structure, working principle, design process and parame⁃ter tuning method. The overall software and hardware solutions for the controller are designed where TMS320F240 DSP is the control core device. Then as an example, a simulation of buck-boost converter under given parameters is run to verify the close loop behavior of the controller. Simulation results show that the new fuzzy PI controller may greatly enhance the static and dynamic performance of the converter system.%  针对DC/DC变换器的强非线性,提出了一种新的模糊PI控制器,将模糊控制方法与传统线性PI的电压、电流双环控制方法结合形成闭环系统。给出了模糊PI控制器的结构原理、设计过程和参数整定方法,并对给定参数的buck-boost变换器作为实例进行了仿真验证,同时以TMS320F2812DSP为核心控制器件,设计了系统整体实现的软硬件方案。仿真结果表明,新的模糊PI控制器能够较大地提升系统的动、静态性能。

  12. 几种新型的Buck-Boost变换器的合成%Synthesis of Several Novel Buck-Boost Converters

    Institute of Scientific and Technical Information of China (English)

    朱继承; 蔡丽娟

    2008-01-01

    从传输机制说明单管升降压变换器(如Buck-Boost、SPEIC、Cuk)中元件承受的电压和电流应力高的原因,并根据这一机制,采用变换器合成的方式,提出了一系列的双管Buck-Boost变换器.这类变换器根据输入输出条件,可以分别工作于Boost模式和Buck模式,起到降低元件应力的作用.

  13. Buck-Boost型变换器电路结构及其演化%Circuit Configuration and Derivation of the Buck-Boost Converter

    Institute of Scientific and Technical Information of China (English)

    张灵改; 陈道炼

    2009-01-01

    论述了基于Buck-Boost型变换器的DC/DC,DC/AC和AC/AC变换器电路结构及其演化过程,给出了各类变换器的电路拓扑实例、仿真和原理试验结果.理论分析、仿真和原理试验结果表明,Buck-Boost型变换器在中小容量的DC/DC.DC/AC和AC/AC电能变换中具有重要的应用价值.

  14. 基于Matlab的Boost-Buck Chopper的建模与仿真%Modeling and simulation of Boost-Buck Chopper based on MATLAB

    Institute of Scientific and Technical Information of China (English)

    孟庆波; 崔刚

    2012-01-01

    对Matlab进行了简单介绍,建立了IGBT的仿真模型,运用Matlab/Simulink和Power System工具对Boost- Buck Chopper进行建模、参数选择和仿真分析.与常规电路分析方法相比,该方法具有很大的优越性.%The paper takes a brief introduction to MATLAB, and establishes a simulation model ofIGBT. It uses Matlab/Simulink and Power System tools to model, chooses parameters and simulatesBoost-Buck Chopper. Compared with conventional circuit analysis methods, this method has greatadvantages.

  15. SUPERFUND GROUND WATER ISSUE - ACCURACY OF DEPTH TO WATER MEASUREMENTS

    Science.gov (United States)

    Accuracy of depth to water measurements is an issue identified by the Forum as a concern of Superfund decision-makers as they attempt to determine directions of ground-water flow, areas of recharge of discharge, the hydraulic characteristics of aquifers, or the effects of manmade...

  16. Li-Ion Battery Charging with a Buck-Boost Power Converter for a Solar Powered Battery Management System

    OpenAIRE

    2013-01-01

    This paper analyzes and simulates the Li-ion battery charging process for a solar powered battery management system. The battery is charged using a non-inverting synchronous buck-boost DC/DC power converter. The system operates in buck, buck-boost, or boost mode, according to the supply voltage conditions from the solar panels. Rapid changes in atmospheric conditions or sunlight incident angle cause supply voltage variations. This study develops an electrochemical-based equivalent circuit mod...

  17. Ecology of juvenile hawksbills (Eretmochelys imbricata) at Buck Island Reef National Monument, US Virgin Islands

    Science.gov (United States)

    Hart, Kristen M.; Sartain-Iverson, Autumn R.; Hillis-Starr, Zandy; Phillips, Brendalee; Mayor, Philippe A.; Roberson, Kimberly; Pemberton, Roy A.; Allen, Jason B.; Lundgren, Ian; Musick, Susanna

    2013-01-01

    Surveys of juvenile hawksbills around Buck Island Reef National Monument, US Virgin Islands from 1994 to 1999 revealed distributional patterns and resulted in a total of 75 individual hawksbill captures from all years; turtles ranged from 23.2 to 77.7 cm curved carapace length (CCL; mean 42.1 ± 12.3 cm SD). Juveniles concentrated where Zoanthid cover was highest. Length of time between recaptures, or presumed minimum site residency, ranged from 59 to 1,396 days (mean 620.8 ± 402.4 days SD). Growth rates for 23 juveniles ranged from 0.0 to 9.5 cm year−1 (mean 4.1 ± 2.4 cm year−1SD). Annual mean growth rates were non-monotonic, with the largest mean growth rate occurring in the 30–39 cm CCL size class. Gastric lavages indicated that Zoanthids were the primary food source for hawksbills. These results contribute to our understanding of juvenile hawksbill ecology and serve as a baseline for future studies or inventories of hawksbills in the Caribbean.

  18. Computer Simulation Based Study of a Buck-Boost Circuit%基于计算机仿真的Buck-Boost电路研究

    Institute of Scientific and Technical Information of China (English)

    王利清; 魏学业; 温伟刚

    2004-01-01

    Buck-Boost电路中含有丰富的非线性现象.它工作过程中电路拓扑结构的循环切换导致了谐波、分叉和混沌等非线性行为.基于PSPICE仿真,研究了电流控制DC/DC Buck-Boost开关转换器中的倍周期现象.而且,建立了开关转换器的数学模型和叠代映射来解释这种非线性现象.基于MATLAB仿真,从叠代映射中得到了系统分叉图.%A buck-boost circuit is rich in nonlinear dynamics. Its operation is characterized by cyclic switching of circuit topologies, which gives rise to a variety of nonlinear, such as subharmonics, bifurcation and chaos. Based on PSPICE, the period-doubling phenomena exhibited by a current-programmed DC/DC buck-boost switching converter are studied. Furthermore, the system model and the iterative map of the converter are derived to explain the nonlinear phenomena. Based on MATLAB, the numerical simulation with this iterative map has led to the bifurcation diagram.

  19. Dual Edge Modulated Four-switch Buck-Boost Converter%双沿调制的四开关Buck-Boost变换器

    Institute of Scientific and Technical Information of China (English)

    任小永; 阮新波; 李明秋; 钱海; 陈乾宏

    2009-01-01

    与传统的Buck-Boost变换器相比,四开关Buck-Boost变换器具有输入输出同极性、开关管电压应力低等优点.该文针对四开关Buck-Boost变换器在通信电源分布式系统中的应用,提出三模式双频双沿调制的控制策略.该控制策略将变换器分成Buck单元和Boost单元,此两单元分别采用后沿调制和前沿调制,并且在Buck.Boost工作模式时,开关频率由Buck以及Boost模式的200 kHz降到40 kHz,以提高变换器的效率.实验室制作了一台48V(33~75 V)输入48 V/6.25 A的样机,对所提出的控制策略进行验证.试验结果表明所得结论正确.

  20. Thoracic aortic aneurysm in a buck associated with caseous lymphadenitis

    Directory of Open Access Journals (Sweden)

    R.R. Pinheiro

    2013-06-01

    Full Text Available This paper reports the clinical, bacteriological and pathological findings of a thoracic aortic aneurysm in a four-year-old Anglo-Nubian goat buck, related to a framework of visceral caseous lymphadenitis. General clinical examination showed heart rate of 75 beats per minute, respiratory rate of 20 movements per minute and ruminal movements of four movements per minute. Superficial lymph nodes were normal upon palpation. Rectal temperature was slightly high (40.5°C. Blood test showed an intense leukocytosis (54,000/µL, characterized by strong neutrophil shift to the left. At necropsy, a large blood clot was detected in the thoracic cavity. The thickening of the myocardium and dilatation of the aorta in the thoracic portion, presenting a saculiform format was also observed. A large number of abscesses were disseminated in the media and intima layers of aorta. The aorta lumen obstruction by arterial plaques consisting of inflammatory infiltrate, predominantly neutrophilic was also detected. Abscesses were found spread in turbinate, rumen, reticulum, kidneys, liver, spleen, testicles and aorta wall. The microbiological exam of exudate confirmed Corynebacterium pseudotuberculosis as the causal agent.

  1. 50 MHz dual-mode buck DC—DC converter

    Science.gov (United States)

    Zhang, Zhang; Xing, Wang; Wencheng, Yu; Ye, Tan; Yizhong, Yang; Guangjun, Xie

    2016-08-01

    A 50 MHz 1.8/0.9 V dual-mode buck DC—DC converter is proposed in this paper. A dual-mode control for high-frequency DC—DC converter is presented to enhance the conversion efficiency of light-load in this paper. A novel zero-crossing detector is proposed to shut down synchronous rectification transistor NMOS when the inductor crosses zero, which can decrease the power loss caused by reverse current and the trip point is adjusted by regulating IBIAS (BIAS current). A new logic control for pulse-skipping modulation loop is also presented in this paper, which has advantages of simple structure and low power loss. The proposed converter is realized in SMIC 0.18 μm 1-poly 6-metal mixed signal CMOS process. With switching loss, conduction loss and reverse current related loss optimized, an efficiency of 57% is maintained at 10 mA, and a peak efficiency of 71% is measured at nominal operating conditions with a voltage conversion of 1.8 to 0.9 V. Project supported by the National Natural Science Foundation of China (Nos. 61404043, 61401137), the Key Laboratory of Infrared Imaging Material and Detectors, Shanghai Institute of Technical Physics, CAS (Nos. IIMDKFJJ-13-06, IIMDKFJJ-14-03), and the Fundamental Research Funds for the Central University (No. 2015HGZX0026).

  2. Analysis of Non-minimum Phase in Buck-Boost Converter

    Directory of Open Access Journals (Sweden)

    Huang Jinfeng

    2016-01-01

    Full Text Available In this paper, relations among the parameters of the non-minimum phase for the Buck-Boost converter are studied. It is demonstrated that when the Buck-Boost converter works in Buck mode, the negative regulation voltage is determined by the converter with the pre-designed inductor and load as the duty ratio D0.382, and the duty ratio has a limited effect on the negative regulation voltage of the converter; when the Buck-Boost converter works in Boost mode,the negative regulation voltage is determined jointly by the converter with its pre-designed inductor, load and duty cycle, for which performs that the higher the output voltage is (i.e., the greater the duty ratio is,the more severe undershoot of the voltage will be. The conclusion of this paper has a guidance meaning for decreasing the negative regulation voltage of the Buck-Boost converter. Finally the correctness of the analysis for the non-minimum phase is verified by simulations and experiments.

  3. Research on Two-channel Interleaved Two-stage Paralleled Buck DC-DC Converter for Plasma Cutting Power Supply

    DEFF Research Database (Denmark)

    Yang, Xi-jun; Qu, Hao; Yao, Chen

    2014-01-01

    As for high power plasma power supply, due to high efficiency and flexibility, multi-channel interleaved multi-stage paralleled Buck DC-DC Converter becomes the first choice. In the paper, two-channel interleaved two- stage paralleled Buck DC-DC Converter powered by three-phase AC power supply...

  4. 75 FR 22168 - ADSOUTH PARTNERS, Inc., American Racing Capital, Inc., Buck-A-Roo$ Holding Corporation, DDS...

    Science.gov (United States)

    2010-04-27

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION ADSOUTH PARTNERS, Inc., American Racing Capital, Inc., Buck-A- Roo$ Holding Corporation, DDS... there is a lack of current and accurate information concerning the securities of Buck-A-Roo$ Holding...

  5. Semen characteristics and sperm morphological studies of the West African Dwarf Buck treated with Aloe vera gel extract

    Directory of Open Access Journals (Sweden)

    Oyeyemi Matthew Olugbenga

    2011-01-01

    Full Text Available Background: Aloe vera (Aloe barbadensis miller is an evergreen perennial plant widely used in modern herbal practice and is often available in proprietary herbal preparations.Objective: This study was designed to investigate the semen picture and spermatozoa morphology of West African Dwarf (WAD bucks treated with Aloe vera extract.Materials and Methods: Twelve sexually matured WAD bucks, weighing between 11 and 15 kg, were used for the study. The bucks were first used as control (pre-treatment and later as two groups of six animals each. The first six bucks received 10 mls of the 3% extract while the other six received 10 mls of the 4% of the extract for a 7 day period. Semen was collected from both the 3 and 4% extract treated bucks for the control (pre-treatment, on days eight (first week post-treatment and fifteen (second week post-treatment in each case using the electroejaculation method. The spermiogram of the bucks were investigated using standard procedures. Data obtained were analyzed using two way ANOVA and significance reported at p<0.05.Results: The continuous administration of Aloe vera extract significantly (p<0.05 reduced sperm concentration, motility and percentage livability and resulted in increased sperm abnormalities in the WAD buck.Conclusion: Aloe vera adversely affected the spermiogram of bucks. The plant can reduce fertility in male animals and is therefore not recommended for medicinal purpose in male animals especially those used for breeding.

  6. Waste of Felling and On-Site Production of Teak Squarewood of the Community Forest

    Directory of Open Access Journals (Sweden)

    Ahmad Budiaman

    2012-12-01

    Full Text Available Major suppliers of teak wood for the raw material of furniture industry in Indonesia are Perum Perhutani, community forests, and private forests.  Community teak forest management produce roundwood or squarewood, in which squarewood is produced on the felling site by the use of chainsaw after felling and bucking activities. Utilization of teak wood from community forest has been practiced for decades, however information on the extent of utilization and the quantity of wood waste have not been published to a greater extent. The present research was intended to determine and analyze the extent of utilization and teak wood waste produced from felling and bucking, and on-site squarewood production of community forests.  Quantification of wood waste from felling and bucking was based on the whole tree method, while that of squarewood production was based on the percentage of yield. It was found that the quantity of teak felling and bucking wood waste in community forest was reaching 28% of felled wood volume that consisted of branch and twig (46.15%, upper trunk (30.77%, short cut off (15.38%, and stumps (7.69%. The largest part of the wood waste of teak felling and bucking satisfied the requirement as raw material of wood working industry according to Indonesian National Standard. On-site production of squarewood increased the quantity of wood waste in the forests (in the form of slabs and sawdust.Keywords: wood waste, felling, bucking, squarewood, community forest

  7. Nonlinear Phenomena and Resonant Parametric Perturbation Control in QR-ZCS Buck DC-DC Converters

    Science.gov (United States)

    Hsieh, Fei-Hu; Liu, Feng-Shao; Hsieh, Hui-Chang

    The purpose of this study is to investigate the chaotic phenomena and to control in current-mode controlled quasi-resonant zero-current-switching (QR-ZCS) DC-DC buck converters, and to present control of chaos by resonant parametric perturbation control methods. First of all, MATLAB/SIMULINK is used to derive a mathematical model for QR-ZCS DC-DC buck converters, and to simulate the converters to observe the waveform of output voltages, inductance currents and phase-plane portraits from the period-doubling bifurcation to chaos by changing the load resistances. Secondly, using resonant parametric perturbation control in QR-ZCS buck DC-DC converters, the simulation results of the chaotic converter form chaos state turn into stable state period 1, and improve ripple amplitudes of converters under the chaos, to verify the validity of the proposes method.

  8. On the Disillusionment of American Dream Through Buck in The Call of the Wild

    Institute of Scientific and Technical Information of China (English)

    吕颖

    2015-01-01

    The Call of the Wild,written by the famous American novelist Jack London,has attracted a large number of both readers and scholars ever since it came out.It provides the public with a fresh perspective through narrating the whole novel from the point of view of the protagonist Buck,a dog.Against the background of countless people flooding into the Alaska to search gold in order to fulfill their dream of becoming rich,which,to some extent,represents the American dream at that time,this novel vividly mirrored the then phenomenon,so illuminating and thought-provoking that it is of great value to analyze the disillusionment of American Dream through Buck.Therefore,this paper aims at exploring the disillusionment of American Dream through analyzing Buck and his rich life experiences.

  9. Energy iteration model research of DCM Buck converter with multilevel pulse train technique

    Science.gov (United States)

    Qin, Ming; Li, Xiang

    2017-08-01

    According as the essence of switching converter is the nature of energy, the energy iteration model of the Multilevel Pulse Train (MPT) technique is studied in this paper. The energy iteration model of DCM Buck converter with MPT technique can reflect the control law and excellent transient performance of the MPT technique. The iteration relation of energy transfer in switching converter is discussed. The structure and operation principle of DCM Buck converter with MPT technique is introduced and the energy iteration model of this converter is set up. The energy tracks of MPT-control Buck converter and PT converter is researched and compared to show that the ratio of steady-state control pulse satisfies the expectation for the MPT technique and the MPT-controlled switching converter has much lower output voltage ripple than the PT converter.

  10. Non-Inverting Buck-Boost Converter for Fuel Cell Applications

    DEFF Research Database (Denmark)

    Schaltz, Erik; Rasmussen, Peter Omand; Khaligh, Alireza

    2008-01-01

    Fuel cell DC/DC converters often have to be able to both step-up and step-down the input voltage, and provide a high efficiency in the whole range of output power. Conventional negative output buck-boost and non-inverting buck-boost converters provide both step-up and step-down characteristics....... In this paper the non-inverting buck-boost with either diodes or synchronous rectifiers is investigated for fuel cell applications. Most of previous research does not consider  the parasitic in the evaluation of the converters. In this study, detailed analytical expressions of the efficiencies for the system...... composed of fuel cell system and interfacing converter, considering the parasitics, are presented. It is concluded that the implementation with synchronous rectifiers provides the highest efficiency in the whole range of the fuel cell power, and its efficiency characteristic is more suitable for fuel cell...

  11. Analysis of Discharge Spark Energy in Buck Converter of a Continuous Mode of Inductive Current

    Institute of Scientific and Technical Information of China (English)

    CUI Bao-chun; CHENG Hong; WANG Cong; LU Huan-yu; SHI Yun

    2006-01-01

    The basic idea of intrinsically safe circuit and the discharge spark in the Buck converter in the explosive atmospheres were introduced. The Buck converter is the main topological structure of the switch type of intrinsically safe circuit, which has two working modes: continuous inductive current (CCM - continuous conduction mode) and discrete inductance current (DCM - discontinuous conduction mode). The operating state of the continuous inductive current mode is analyzed in detail and the energy of discharge spark in various operating modes is discussed. The total energy will decrease with the increase of switch frequency, in a switching cycle; the discharge spark energy has a maximum and a minimum value. Therefore, the Buck converter has smaller discharge spark energy than the linear power circuit and the switch type of intrinsically safe circuit can enhance the output power and the conversion efficiency of the intrinsically safe power.

  12. Application of Theory of Hybrid Systems to Control the Switching of Buck Converter

    KAUST Repository

    Benmiloud, Mohammed

    2013-08-01

    The field of power electronics poses challenging control problems that can’t be treated in a complete manner using traditional modeling. In this paper, the buck converter operating in Continuous Conduction Mode (CCM) is represented analytically by hybrid automaton model and graphically representation is also given. The hybrid trajectory and the model behavior are presented. The control problem of buck switching converters is transformed to a guard selection problem. The guard selection calculation formulas of buck converter are derived from the basic circuit laws. The stability of the switching is established analytically by the use of multiple Lyapunov functions to ensure the convergence and Poincare map to assess the local stability of the limit cycle. Numerical results clearly bring out the advantages and effectiveness of the proposed control law under varying line voltage and load conditions. Simulation studies are carried out in Matlab/Simulink/Stateflow.

  13. Modeling and design of DCM Buck-Boost converter%DCM Buck-Boost变换器的建模与控制设计

    Institute of Scientific and Technical Information of China (English)

    方露; 党幼云; 康朋飞

    2015-01-01

    DC converter has the characteristics of nonlinear and multi modal .The model building of Buck-Boost converter is the key to design its closed-loop control system. The reliable output voltage and perfect dynamic characteristic of the Buck-Boost converter was greatly influenced by it. The AC small signal model is build on the basis of Buck-Boost converter's average switch model. Then get the transfer function of system. The voltage loop was also designed based on it. The design details for voltage loop were given and zero-pole compensation method from classic control theory was applied to the field of power electronics. The design of closed-loop control system and the model were verified through the analysis of the result of simulation in MATLAB software.%直流变换器一般具有非线性、多模态等特点。 Buck-Boost变换器的建模是其闭环控制设计的关键,对于Buck-Boost变换器输出可靠的电压和良好的动态响应特性具有非常重要的影响。本文是在Buck-Boost变换器断续模式的平均开关模型基础上建立其小信号交流模型,并推导出系统传递函数。在此基础上设计了电压闭环控制系统,进行了电压闭环参数设计的研究,实现了控制理论中零极点补偿法在电力电子中的应用。利用MATLAB软件进行仿真分析,验证了模型和闭环控制设计的正确性。

  14. Study on Nonlinear Phenomena in Buck-Boost Converter with Switched-Inductor Structure

    OpenAIRE

    2013-01-01

    The switched-inductor structure can be inserted into a traditional Buck-Boost converter to get a high voltage conversion ratio. Nonlinear phenomena may occur in this new converter, which might well lead the system to be unstable. In this paper, a discrete iterated mapping model is established when the new Buck-Boost converter is working at continuous conduction current-controlled mode. On the basis of the discrete model, the bifurcation diagrams and Poincare sections are drawn and then used t...

  15. PWM Technique for Non-Isolated Three-Phase Buck-Boost PFC Converter

    Science.gov (United States)

    Morizane, Toshimitsu; Shimomori, Wataru; Taniguchi, Katsunori; Kimura, Noriyuki; Ogawa, Masanori

    The buck-boost power factor corrected (PFC) converter has the wide range of the dc output voltage. A new non-isolated three-phase hard-switching and a soft-switching buck-boost PFC converter are proposed. Removing the three-phase transformer from the converters makes their size more compact and their costs lower. In addition, the new control method based on the PWM technique is proposed in this paper to achieve the high power factor. Complete soft-switching is also achieved under the discontinuous current mode (DCM) operation.

  16. Modeling and Analysis of Transformerless High Gain Buck-boost DC-DC Converters

    Directory of Open Access Journals (Sweden)

    Vu Tran

    2014-12-01

    Full Text Available This paper proposes a transfomerless switched capacitor buck boost converter model, which provides higher voltage gain and higher efficiency when compared to the conventional buck boost converter. The averaged model based on state-space description is analyzed in the paper. The simulation results are presented to confirm the capability of the converter to generate high voltage ratios. The comparison between the proposed model and the traditional model is also provided to reveal the improvement. The proposed converter is suitable for for a wide application which requires high step-up DC-DC converters such as DC micro-grids and solar electrical energy.

  17. Finite-time control of DC-DC buck converters via integral terminal sliding modes

    Science.gov (United States)

    Chiu, Chian-Song; Shen, Chih-Teng

    2012-05-01

    This article presents novel terminal sliding modes for finite-time output tracking control of DC-DC buck converters. Instead of using traditional singular terminal sliding mode, two integral terminal sliding modes are introduced for robust output voltage tracking of uncertain buck converters. Different from traditional sliding mode control (SMC), the proposed controller assures finite convergence time for the tracking error and integral tracking error. Furthermore, the singular problem in traditional terminal SMC is removed from this article. When considering worse modelling, adaptive integral terminal SMC is derived to guarantee finite-time convergence under more relaxed stability conditions. In addition, several experiments show better start-up performance and robustness.

  18. Bifurcation and Chaos in a Pulse Width modulation controlled Buck Converter

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz; Bak, Claus Leth; Munk-Nielsen, Stig

    2007-01-01

    by a system of piecewise-smooth nonautonomous differential equations. The research are focused on chaotic oscillations analysis and analytical search for bifurcations dependent on parameter. The most frequent route to chaos by the period doubling is observed in the second order DC-DC buck converter. Other...... bifurcations as a complex behaviour in power electronic system evidence are also described. In order to verify theoretical study the experimental DC-DC buck converter was build. The results obtained from three sources were presented and compared. A very good agreement between theory and experiment was observed....

  19. A unified active damping control for single-phase differential buck inverter with LCL-filter

    DEFF Research Database (Denmark)

    Yao, Wenli; Wang, Xiongfei; Zhang, Xiaobin

    2015-01-01

    The single-phase differential mode buck inverter is recently introduced with a differential mode for power transfer and a common mode for actively decoupling the second-order power oscillation. However, it is limited to islanded applications with an LC filter. This paper addresses the stability...... and control of a grid-connected differential mode buck inverter with an LCL filter. A generalized small-signal model of the inverter is built first with the averaged switching model. It is shown that the LCL filter resonance merely occurs in the differential mode, while an LC filter resonance exists...

  20. Steady-state analysis of dead-time effect on bidirectional buck converters

    DEFF Research Database (Denmark)

    Bidoggia, Benoit; Maheshwari, Ram Krishan; Nielsen, Rasmus Ørndrup

    2012-01-01

    Half-bridge inverters, full-bridge inverters and bidirectional buck converters share a common topological structure, in which two switches and two diodes are present. In such a topology, a dead time between the two signals controlling the switches is inserted. This influences the relationship...... proposed. However, the measurement of the current is normally required for all dead-time compensation strategies, which can be a problem when the current approaches or crosses zero. In this paper, the operation of a bidirectional buck converter in the region around zero current has been analytically...

  1. A Novel Single Switch Transformerless Quadratic DC/DC Buck-Boost Converter

    DEFF Research Database (Denmark)

    Mostaan, Ali; A. Gorji, Saman; N. Soltani, Mohsen

    2017-01-01

    A novel quadratic buck-boost DC/DC converter is presented in this study. The proposed converter utilizes only one active switch and can step-up/down the input voltage, while the existing single switch quadratic buck/boost converters can only work in step-up or step-down mode. First, the proposed ...... converter is analyzed in steady-state. Then, its performance is validated using simulations in MATLAB/SIMULINK software. Finally, an experimental prototype is built for further verification....

  2. Analisys of Current-Bidirectional Buck-Boost Based Automotive Switch-Mode Audio Amplifier

    DEFF Research Database (Denmark)

    Bolten Maizonave, Gert; Andersen, Michael A. E.; Kjærgaard, Claus

    2011-01-01

    The following study was carried out in order to assess quantitatively the performance of the buck-boost converter when used as switch-mode audio amplifier. It comprises of, to begin with, the delimitation of design criteria based on the state-ofthe- art solution, which is based in a differential...... mode buck-based amplifier with a boost converter as power supply. The averaged switch modelling of the differential mode current bidirectional topology is also used, in order to analyze the steady state and frequency domain behaviour of this converter and parameterize it to meet the design criteria...... in such configuration when applied for audio....

  3. Superfund/IGD: EF_NPL

    Data.gov (United States)

    U.S. Environmental Protection Agency — EF_NPL is a subset of facilities from FRS_INTEREST and FRS_FACILITY_SITE which are updated on a monthly basis as part of the Locational Reference Tables (LRT)...

  4. 基于改善关联性 Buck 变换器的混沌控制*%Chaotic control of the Buck converter based on improving the correlation∗

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      由于 Buck 变换器具有非线性特性,在一定参数条件下,它会处于混沌状态,此时 Buck 变换器不能正常工作。为了抑制 Buck 变换器的混沌现象,本文首先建立了 Buck 变换器的精确状态方程模型,然后通过分析可控范围图、开关逻辑图、相图、电感电流波形、输出电压波形,研究了基于改善 Buck 变换器的电感电流与输出电压之间关联性的混沌控制策略。研究结果表明:该控制策略能够将处于混沌状态的 Buck 变换器稳定在周期1,2,4,8轨道,且该控制策略不需要预先确定期望的目标轨道,不依赖于 Buck 变换器的电路参数,只取决于一个外部参数即耦合强度,所以该控制策略同样适用于其他拓扑结构的功率变换器。%Due to the strong nonlinearity of the Buck converter, it can be in the chaotic state under certain parameters and the chaotic Buck converter does not work normally. In order to suppress the chaotic phenomena in the Buck converter, a chaotic control scheme is demonstrated by establishing the accurate state equation models, and then analyzing the controllable range diagrams, the switching logic diagrams, the phase portrait, the inductor current waveforms and the output voltage waveforms. Also this scheme can be im-plemented by improving the correlation between the inductor current and the output voltage of the Buck converter. Research results show that this scheme can stabilize the chaotic Buck converter to the period-1, period-2, period-4, period-8 orbits, without determining the desired targeting orbits in advance. Moreover, this scheme does not depend on circuit parameters of the Buck converter, it only depends on an external parameter named the coupling strength, so this scheme can be applied to the other power converters.

  5. The Design and Implement of Digital Controller for Buck-Boost Converter%Buck-Boost变换器数字控制器的设计和实现

    Institute of Scientific and Technical Information of China (English)

    何炯; 吴定会; 纪志成

    2008-01-01

    利用分段线性电子电路仿真PLECS软件建立Buck-Boost变换器的仿真模型;采用幅值相位裕度方法设计控制器参数;基丁系统发生器提出了一种新的数字控制器实现方法,分析了负载扰动和电源扰动特性.并对其进行了实验.实验结果证明了PLECS建模和系统发生器设计的有效性,也为FPGA实现Buck-Boost变换器的数字控制器提供了新的设计流程.

  6. The Passivity-based Current Control Method for BUCK-BOOST Converter%BUCK-BOOST变换器的无源性电流控制方法

    Institute of Scientific and Technical Information of China (English)

    廖鸿飞; 帅定新; 梁奇峰; 彭建宇

    2013-01-01

    为了简化系统控制结构,提高Buck-Boost变换器的控制性能,提出了一种通过直接控制电感电流间接控制输出电压的Buck-Boost变换器无源性电流控制方法.首先根据无源性控制方法建立了系统的欧拉一拉格朗日能量模型,然后基于无源性理论和Layapunov稳定性理论,推导出了系统的无源性控制规律.实验结果表明,系统输出电压稳定,鲁棒性较强,动态响应良好.

  7. Fractional Order Modeling and Analysis of Buck-Boost Converter%基于分数阶Buck-Boost变换器建模与分析

    Institute of Scientific and Technical Information of China (English)

    伊利峰; 张开如; 刘军

    2015-01-01

    Buck-Boost变换器应用相关分数阶微积分理论建立基于电感电流连续模式下分数阶数学模型,然后理论分析建立起来的分数阶数学模型.基于改进的分数阶微积分Oustaloup滤波器算法,建立电感电流连续模式下Buck-Boost变换器Matlab/Simulink分数阶仿真模型.最后,分数阶仿真结果与整数阶的结果进行分析比较,验证分数阶数学模型与理论分析的正确性.

  8. A Novel Four Switch Buck-Boost Converter%一种新颖的四开关Buck-Boost变换器

    Institute of Scientific and Technical Information of China (English)

    任小永; 唐钊; 阮新波; 危建; 华桂潮

    2008-01-01

    提出一种新颖的四开关Buck-Boost变换器及其控制策略.该变换器由Buck变换器和Boost变换器级联等效而成,其可以将宽范围的输入电压高效率变换到额定电压附近,这样对后级变换器而言输入就是一个窄范围,从而保证了后级变换器的优化设计;与此同时,四开关Buck-Boost变换器的滤波工作模式还保证了额定输入电压附近效率的最高.实验结果表明:采用文中提出的四开关Buck-Boost变换器作为前级的两级式变换器可以满足未来通信电源模块高效率、高功率密度以及宽输入范围的要求.

  9. Design of AC Regulator Based on Buck-Boost Converter%基于Buck-Boost的AC/AC变换器设计

    Institute of Scientific and Technical Information of China (English)

    张超华; 汤雨; 谢少军

    2007-01-01

    利用Buck-Boost电路输出电压理论上可以在零到无穷大之间变化的特点,将Buck- Boost斩波电路应用于交流电压变换,提出了一种变比可以连续变化的固态变压器.与传统的自耦调压器相比,基于Buck-Boost变换器的固态变压器具有输出电压范围宽、体积小的特点,并且由于采用了电压反馈控制,使得其输出电压不受负载变化的影响,外特性较硬.针对四象限开关存在的换流问题,提出了该变换器的换流策略,在理论分析的基础上,设计制作了一台AC/AC调压器,实验结果验证了该变换器的可行性.

  10. Topological Design and Modulation Strategy for Buck-Boost Three-Level Inverters

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Gao, F.; Blaabjerg, Frede;

    2007-01-01

    To date, designed topologies for dc-ac inversion with both voltage-buck and boost capabilities are mainly focused on two-level circuitries with extensions to three-level possibilities left nearly unexplored. Contributing to this area of research, this paper presents the design of a number of viable...

  11. Interleaved Buck Converter with Variable Number of Active Phases and a Predictive Current Sharing Scheme

    DEFF Research Database (Denmark)

    Jakobsen, Lars Tønnes; Garcia, O.; Oliver, J. A.

    2008-01-01

    The efficiency of an interleaved Buck converter is typically low at light load conditions because of the switching losses in each of the switching stages. Improvements in the converter efficiency can be achieved by dynamically changing the number of active phases depending on the load current...

  12. Pulse width modulated buck-boost five-level current source inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Gao, F.; Loh, P.C.;

    2008-01-01

    This paper presents new five-level current source inverters (CSIs) with voltage/current buck-boost capability. Being different from the existing multilevel CSI, the proposed CSIs were first designed to regulate the flowing path of dc input current by controlling two additional active switches, re...

  13. "Class-Bucks": A Motivational Tool to Encourage Active Student Participation during Lectures

    Science.gov (United States)

    de Jager, T.

    2013-01-01

    The purpose of this study was to ascertain the influence of an extrinsic motivational tool, "class-bucks," on the possibility of improving first year student-teachers' participation in active learning at Tshwane University of Technology in South Africa. Research participants (n=289) were divided into four classes and engaged in this…

  14. Intensive hardwood log bucker training using HW Buck dramatically improves value recovery

    Science.gov (United States)

    James B. Pickens; Aaron Everett; Scott Noble; John E. Baumgras; Philip A. Araman; Conrad Waniger; Al Steele

    2006-01-01

    It has long been recognized that inappropriate placement of crosscuts when manufacturing hardwood logs from harvested stems (log bucking) reduces the value of logs produced. Recent studies have estimated losses in the range from 28% to 38% in the lake states region. It has not, however, been clear how to correct the problem. Efforts to improve value recovery have...

  15. A Tapped-Inductor Buck-Boost Converter for a Dielectric ElectroActive Polymer Generator

    DEFF Research Database (Denmark)

    Dimopoulos, Emmanouil; Munk-Nielsen, Stig

    2014-01-01

    of commercially-available, high-efficient, high-voltage, low-power semiconductor devices. In this paper, a high-efficient bidirectional tapped-inductor buck-boost converter, addressing high step-up and high step-down voltage conversion ratios, is proposed for energy harvesting applications based on DEAP...

  16. Two-Phase Interleaved Buck Converter with a new Digital Self-Oscillating Modulkator

    DEFF Research Database (Denmark)

    Jakobsen, Lars Tønnes; Andersen, Michael Andreas E.

    2007-01-01

    for traditional digital PWM modulators given a certain switching frequency. A synchronised version of the DiSOM modulator is derived for interleaved converters. A prototype interleaved Buck converter for Point of Load applications has been designed and built to test the performance of DiSOM modulator. The Di...

  17. Effect of Cage Type on Fecal Corticosterone Concentration in Buck Rabbits During the Reproductive Cycle.

    Science.gov (United States)

    Cornale, Paolo; Macchi, Elisabetta; Renna, Manuela; Prola, Liviana; Perona, Giovanni; Mimosi, Antonio

    2016-01-01

    Fecal corticosterone concentration (FCC) was measured in 14 buck rabbits individually housed in standard-dimension cages (SC) or in bigger cages (BC; with a volume more than double that of SC and equipped with a plastic foot mat) during 4 consecutive reproductive cycles. Cage type and reproductive phase (estrous synchronization of doe rabbits, artificial insemination, partum, preweaning, and postweaning) were not statistically significant but tendentially affected FCCs (.05 Buck rabbits housed in SC showed higher FCCs than those housed in BC (27.42 pg g(- 1) dried feces and 25.57 pg g(- 1), respectively; SEM = 2.952). The highest FCC values were detected at artificial insemination (BC, 27.91 pg g(- 1); SC, 30.45 pg g(- 1); SEM = 3.520), highlighting that the phase of semen collection could be one of the most critical moments for buck rabbits, although further investigations are needed. These preliminary results suggest that measurement of FCC could be used as an indicator of chronic stress in buck rabbits.

  18. Three Phase Six-Switch PWM Buck Rectifier with Power Factor Improvement

    DEFF Research Database (Denmark)

    Zafar Ullah Khan, M; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar

    2013-01-01

    Conventional Phase Controlled Rectifier injects low order current harmonics into the AC mains. Large size filtering components are required to attenuate these harmonics. In this paper, Three Phase Six-Switch PWM Buck Rectifier[1] is presented which operates at nearly unity power factor and provides...

  19. Novel Family of modified qZS buck-boost multilevel inverters with reduced switch count

    DEFF Research Database (Denmark)

    Husev, Oleksandr; Strzelecki, Ryszard; Blaabjerg, Frede

    2015-01-01

    This paper describes a novel family of modified quasi-Z-source buck-boost multilevel inverters with reduced switch count. The inverters are derived by means of the modified inverter configuration with quasi-Z-source networks. The main benefits of the proposed solutions lie in the increased amount...

  20. On the Behaviour of Current-Carrying Wire-Conductors and Bucking of a Column

    DEFF Research Database (Denmark)

    Ganji, S. S.; Barari, Amin; Fereidoon, A.

    2013-01-01

    -conductors and bucking of a column as well as their comparisons with the exact solutions are presented. Different specific parameters and initial values comprising the mass and stiffness are studied within the current research and excellent accuracy which is the most significant feature of the proposed solutions...

  1. Global analysis of a buck regulator. [for voltage using discrete control law

    Science.gov (United States)

    Edwards, D. B.; Caughey, T. K.

    1978-01-01

    Sufficient conditions for global stability of a buck regulator using a discrete control law are found. The method of paired systems and Liapunov functions are used to establish global stability and to study the convergence of the regulator. A heuristic argument is given that the optimal switching curves associated with the paired continuous systems approximate the optimal switching curves of the discrete systems.

  2. Circuit Simulation for Solar Power Maximum Power Point Tracking with Different Buck-Boost Converter Topologies

    Directory of Open Access Journals (Sweden)

    Jaw-Kuen Shiau

    2014-08-01

    Full Text Available The power converter is one of the essential elements for effective use of renewable power sources. This paper focuses on the development of a circuit simulation model for maximum power point tracking (MPPT evaluation of solar power that involves using different buck-boost power converter topologies; including SEPIC, Zeta, and four-switch type buck-boost DC/DC converters. The circuit simulation model mainly includes three subsystems: a PV model; a buck-boost converter-based MPPT system; and a fuzzy logic MPPT controller. Dynamic analyses of the current-fed buck-boost converter systems are conducted and results are presented in the paper. The maximum power point tracking function is achieved through appropriate control of the power switches of the power converter. A fuzzy logic controller is developed to perform the MPPT function for obtaining maximum power from the PV panel. The MATLAB-based Simulink piecewise linear electric circuit simulation tool is used to verify the complete circuit simulation model.

  3. Three Phase Six-Switch PWM Buck Rectifier with Power Factor Improvement

    DEFF Research Database (Denmark)

    Zafar Ullah Khan, M; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar

    2013-01-01

    Conventional Phase Controlled Rectifier injects low order current harmonics into the AC mains. Large size filtering components are required to attenuate these harmonics. In this paper, Three Phase Six-Switch PWM Buck Rectifier[1] is presented which operates at nearly unity power factor and provid...

  4. No boundaries. Texas' Christus Health bucks trend by looking to Mexico for expansion.

    Science.gov (United States)

    Jaklevic, M C

    2001-08-06

    Christus Health has bucked the trend by looking to Mexico for expansion. The Roman Catholic system based in Irving, Texas, bought 51% of Hospital Muquerza in the prosperous northern Mexico state of Nuevo Leon. Christus believes the move makes sense on many levels.

  5. Pole placement method of controlling chaos in DC-DC buck converters

    Institute of Scientific and Technical Information of China (English)

    Zou Yan-Li; Luo Xiao-Shu; Chen Guan-Rong

    2006-01-01

    Based on the mechanism for the generation of chaos in a buck converter, a pole placement method is proposed and applied to controlling the chaos in a circuit. The control circuit is designed and tested. Numerical calculation and circuit implementation demonstrate the validity of this chaos control method.

  6. Seasonal changes in reproductive activity, sperm variables and sperm freezability in Blanca Andaluza bucks

    Directory of Open Access Journals (Sweden)

    Lourdes Gallego-Calvo

    2015-12-01

    Full Text Available Interest in the preservation of endangered breeds such as the Blanca Andaluza goat, has increased and some steps should be therefore taken to ensure it. The study was designed to determine the seasonal reproductive pattern of Blanca Andaluza bucks, and whether this affects the quality of their semen and its freezability over the year. Seven bucks were used and their body weight, testicular weight, plasma testosterone concentration and fresh sperm quality determined every week. The collected sperm was cryopreserved and stored; it was then thawed and the same sperm quality variables measured every fortnight. High plasma testosterone concentrations were recorded during the summer and autumn, and low concentrations were recorded during winter and spring (p<0.001. No differences were seen between seasons in terms of the percentage of bucks ejaculating, the percentage of active bucks, or ejaculate volume. However, the sperm concentration, the total number of sperm per ejaculate, and the values for most fresh sperm variables were lower during the winter period (at least p<0.05. After freezing-thawing, the quality of winter-collected sperm was better, in some respects, than that of summer-collected sperm (at least p<0.05. These results reveal that Blanca Andaluza bucks show seasonal reproductive activity in terms of their plasma testosterone concentration, but no clear change in their sexual behaviour between seasons was observed. The values of fresh sperm variables also vary over the year, reaching their lowest during winter. However, after freezing-thawing, winter-collected sperm is of overall better quality than sperm collected during the summer.

  7. Seasonal changes in reproductive activity, sperm variables and sperm freezability in Blanca Andaluza bucks

    Energy Technology Data Exchange (ETDEWEB)

    Gallego-Calvo, L.; Gatica, M.C.; Santiago-Moreno, J.; Guzmán, J.L.; Zarazaga, L.

    2015-07-01

    Interest in the preservation of endangered breeds such as the Blanca Andaluza goat, has increased and some steps should be therefore taken to ensure it. The study was designed to determine the seasonal reproductive pattern of Blanca Andaluza bucks, and whether this affects the quality of their semen and its freezability over the year. Seven bucks were used and their body weight, testicular weight, plasma testosterone concentration and fresh sperm quality determined every week. The collected sperm was cryopreserved and stored; it was then thawed and the same sperm quality variables measured every fortnight. High plasma testosterone concentrations were recorded during the summer and autumn, and low concentrations were recorded during winter and spring (p<0.001). No differences were seen between seasons in terms of the percentage of bucks ejaculating, the percentage of active bucks, or ejaculate volume. However, the sperm concentration, the total number of sperm per ejaculate, and the values for most fresh sperm variables were lower during the winter period (at least p<0.05). After freezing-thawing, the quality of winter-collected sperm was better, in some respects, than that of summer-collected sperm (at least p<0.05). These results reveal that Blanca Andaluza bucks show seasonal reproductive activity in terms of their plasma testosterone concentration, but no clear change in their sexual behaviour between seasons was observed. The values of fresh sperm variables also vary over the year, reaching their lowest during winter. However, after freezing-thawing, winter-collected sperm is of overall better quality than sperm collected during the summer. (Author)

  8. Resident areas and migrations of female green turtles nesting at Buck Island Reef National Monument, St. Croix, U.S. Virgin Islands

    Science.gov (United States)

    Hart, Kristen M.; Iverson, Autumn; Benscoter, Allison M.; Fujisaki, Ikuko; Cherkiss, Michael S.; Pollock, Clayton; Lundgren, Ian; Hillis-Starr, Zandy

    2017-01-01

    Satellite tracking in marine turtle studies can reveal much about their spatial use of breeding areas, migration zones, and foraging sites. We assessed spatial habitat-use patterns of 10 adult female green turtles (Chelonia mydas) nesting at Buck Island Reef National Monument, U.S. Virgin Islands (BIRNM) from 2011 – 2014. Turtles ranged in size from 89.0 – 115.9 cm CCL (mean + SD = 106.8 + 7.7 cm). The inter-nesting period across all turtles ranged from 31 July to 4 November, and sizes of the 50% core-use areas during inter-nesting ranged from 4.2 – 19.0 km2. Inter-nesting core-use areas were located up to1.4 km from shore and had bathymetry values ranging from -17.0 to -13.0 m. Seven of the ten turtles remained locally resident after the nesting season. Five turtles (50%) foraged around Buck Island, two foraged around the island of St. Croix, and the other three (30%) made longer-distance migrations to Antigua, St. Kitts & Nevis, and Venezuela. Further, five turtles had foraging centroids within protected areas. Delineating spatial areas and identifying temporal periods of nearshore habitat-use can be useful for natural resource managers with responsibility for overseeing vulnerable habitats and protected marine turtle populations.

  9. Buck-Boost Converter Control Based on Port-Controlled Hamiltonian Theory%基于端口受控哈密顿方法的Buck-Boost变换器控制

    Institute of Scientific and Technical Information of China (English)

    王勇; 于海生

    2007-01-01

    应用一种新的端口受控哈密顿(PCH)系统方法,研究了Buck-Boost变换器的建模与PWM控制问题.首先,建立了Buck-Boost变换器的PCH系统数学模型.然后,利用互联和阻尼配置的能量成形方法,给出了Buck-Boost变换器的反馈镇定原理.根据其稳态特性确定了系统期望的平衡点,分析了Buck-Boost变换器平衡点的稳定性,最后设计了控制器.仿真结果表明,该控制器具有很好的性能和应用前景.

  10. Humanism in War—Analysis on Pearl S. Buck's War Outlook in Dragon Seed%Humanism in War—Analysis on Pearl S.Buck's War Outlook in Dragon Seed

    Institute of Scientific and Technical Information of China (English)

    张婷

    2015-01-01

    Pearl S.Buck is a controversial American writer.Dragon Seed is one of her war novels and arouses some readers'mis-understanding because of the vivid description of human loss.This research will focus on the analysis of the characters'person-ality change before and during the enemies'invasion.And then explore Pearl S.Buck's real attitude towards Chinese Anti-Japa-nese War and her buried war outlook.

  11. Bathymetry 1M Grid of St. Croix (Buck Island), US Virgin Islands 2005, UTM 20 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains an ESRI Grid with 1 meter cell size representing the bathymetry of the north shore of St. Croix (Buck Island), US Virgin Islands. NOAA's...

  12. Bathymetry 1M GRID of St. Croix (Buck Island), US Virgin Islands, 2004, UTM 20 WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains an ESRI Grid with 1 meter cell size representing the bathymetry of the north shore of Buck Island St. Croix, US Virgin Islands. NOAA's...

  13. Avoidance High-Frequency Chattering Second-Order Sliding Mode Controller Design: Buck Converter in Wind Power System

    Directory of Open Access Journals (Sweden)

    Yigeng Huangfu

    2012-01-01

    Full Text Available This paper mainly discussed a method of high-frequency second-order sliding mode control for Buck converter in wind power systems. Because the wind energy of nature is always unpredictable and intermittent, the robust control such as sliding mode control is adopted in past literatures. In order to remove the high frequency chattering problem when the traditional sliding mode achieves convergence, the second order sliding mode algorithm is reviewed firstly. Meanwhile, the Buck converter taken as a step-down converter is usually adopted in wind power system, because of its simple structure and good linearity. Under those conditions, the second order sliding mode controller is designed based on Buck converter, especially in high-power wind generation system. The experimental results illustrate that the theory of second order sliding mode can be used in high-power Buck converter. It provides one novel avoidance high frequency chattering method for the technology development of new energy generation system.

  14. GeoTIFF of 3x3 m Bathymetry for Buck Island, St. Croix, 2011, UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a LiDAR (Light Detection & Ranging) 3x3 meter resolution bathymetric surface for an area including and surrounding Buck Island Reef...

  15. NOAA TIFF Graphic- 0.5m Backscatter Mosaic of St. Croix (Buck Island), US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the north shore of Buck Island, St. Croix, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team...

  16. NOAA TIFF Graphic- 0.5m Backscatter Mosaic of St. Croix (Buck Island), US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This geotiff represents a 0.5 meter resolution backscatter mosaic of the north shore of Buck Island, St. Croix, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography...

  17. NOAA ESRI Geotiff- 1m Bathymetry of St. Croix (Buck Island), US Virgin Islands, 2004, UTM 20 WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains an ESRI Geotiff with 1 meter cell size representing the bathymetry of the north shore of Buck Island St. Croix, US Virgin Islands.NOAA's...

  18. Analysis on the Passivity and Sliding-mode Control of the Buck-Boost Converter%Buck-Boost变换器的无源滑模控制研究

    Institute of Scientific and Technical Information of China (English)

    屈鲁

    2013-01-01

    为解决无源性控制时Buck-Boost变换器电压与电流过冲的问题,在无源性控制的基础上加入滑模控制.通过建立Buck-Boost变换器的欧拉-拉格朗日(E-L)模型,可以得到Buck-Boost变换器的无源性控制规律.在此基础上,结合滑模控制原理,设计Buck-Boost变换器的无源滑模控制器.在Matlab环境下,进行Buck-Boost变换器无源滑模控制的动态仿真.仿真结果表明,Buck-Boost变换器的无源滑模控制对电源扰动、负载扰动具有很强的鲁棒性,且动态响应速度快,能够解决无源性控制电压与电流过冲的问题.

  19. 76 FR 13615 - B&B Manufacturing Site; Mobile, Mobile County, AL; Notice of Settlement

    Science.gov (United States)

    2011-03-14

    ... AGENCY B&B Manufacturing Site; Mobile, Mobile County, AL; Notice of Settlement AGENCY: Environmental... Manufacturing Site located in Mobile, Mobile County, Alabama for publication. DATES: The Agency will consider... No. EPA-RO4- SFUND-2011-0192 or Site name B&B Manufacturing Superfund Site by one of the...

  20. 76 FR 2112 - Peach Orchard Road Groundwater Plume Site, Augusta, Richmond County, GA; Notice of Settlement

    Science.gov (United States)

    2011-01-12

    ... AGENCY Peach Orchard Road Groundwater Plume Site, Augusta, Richmond County, GA; Notice of Settlement... costs concerning the Peach Orchard Road Groundwater Plume Site located in Augusta, Richmond County... Site name Peach Orchard Road Groundwater Plume Superfund Site by one of the following methods: http...

  1. A new approach to improve dynamic characteristics of digitally controlled buck-boost dc-dc converter

    OpenAIRE

    2010-01-01

    This paper presents a new digital control buck-boost dc-dc converter with bias model to improve dynamic characteristics. The buck-boost converter needs to respond appropriately to changing input voltage and load change with wide input voltage. This approach makes adjustment to the bias value by input voltage and output current. As a result, it is revealed that not only the dynamic characteristics but also static characteristics can be improved and it is effective for wide range input voltage.

  2. Li-Ion Battery Charging with a Buck-Boost Power Converter for a Solar Powered Battery Management System

    Directory of Open Access Journals (Sweden)

    Chien-Wei Ma

    2013-03-01

    Full Text Available This paper analyzes and simulates the Li-ion battery charging process for a solar powered battery management system. The battery is charged using a non-inverting synchronous buck-boost DC/DC power converter. The system operates in buck, buck-boost, or boost mode, according to the supply voltage conditions from the solar panels. Rapid changes in atmospheric conditions or sunlight incident angle cause supply voltage variations. This study develops an electrochemical-based equivalent circuit model for a Li-ion battery. A dynamic model for the battery charging process is then constructed based on the Li-ion battery electrochemical model and the buck-boost power converter dynamic model. The battery charging process forms a system with multiple interconnections. Characteristics, including battery charging system stability margins for each individual operating mode, are analyzed and discussed. Because of supply voltage variation, the system can switch between buck, buck-boost, and boost modes. The system is modeled as a Markov jump system to evaluate the mean square stability of the system. The MATLAB based Simulink piecewise linear electric circuit simulation tool is used to verify the battery charging model.

  3. Research on Buck-Boost Double Half Bridge DC/DC Converter%Buck-Boost型双半桥DC/DC变换器研究

    Institute of Scientific and Technical Information of China (English)

    施林涵; 林国庆; 徐质彬; 林威伟

    2016-01-01

    本文设计了一个应用于光伏系统中的Buck-Boost型双半桥DC/DC变换器,研究一种PWM控制与移相控制结合的充电与供电控制策略:通过移相控制实现光伏电池对负载的供电,通过PWM控制实现光伏电池对蓄电池的充电.最后结合仿真和实验结果,验证了该方案的可行性.

  4. Incremental Conductance MPPT Algorithm for PV System Implemented Using DC-DC Buck and Boost Converter

    Directory of Open Access Journals (Sweden)

    Dhananjay Choudhary

    2014-08-01

    Full Text Available The two basic topologies of switch mode DC-DC converters (Buck and Boost are analyzed with a view of their use in PV (photovoltaic systems, as the photovoltaic generator exhibits non-linear characteristics due to the change in environmental condition and load variation. As the efficiency of PV panels is low it becomes mandatory to extract maximum power from the PV panel at a given period of time. Several MPPT algorithms with different types of converters are being proposed for extracting maximum power from the PV panel. It is found that the nature of load plays an important role in the choice of topology. This paper investigates the implementation issues of Incremental Conductance method with Buck and Boost Converters. Mathematical analysis and desirable steady-state operating point of the converters are derived to give satisfactory maximum power point tracking operation.

  5. A New Zero Voltage Switching Buck-Boost Type DC-DC Converter

    Directory of Open Access Journals (Sweden)

    Majid Delshad

    2010-03-01

    Full Text Available In this paper, a new zero voltage switching isolated buck-boost DC-DC converter with active clamp circuit is proposed. The active clamp circuit in this converter not only absorbs voltage spikes across the main switch but also provides soft switching conditions for all switches. All switches are PWM controlled which simplifies the control implementation. One of the main advantages of this converter is the that it operating can operate at high power levels while soft switching conditions exist in both buck and boost modes of converter operation. Since this converter can operate over a wide input voltage range, it can be employed in power factor correction. The experimental results obtained from a 150W prototype circuit operating at 100KHz are presented to confirm the integrity of the proposed circuit.

  6. Fractional order Buck-Boost converter in CCM: modelling, analysis and simulations

    Science.gov (United States)

    Wang, Faqiang; Ma, Xikui

    2014-12-01

    In this paper, the modelling, analysis and the power electronics simulator (PSIM) simulations of the fractional order Buck-Boost converter operating in continuous conduction mode (CCM) operation are investigated. Based on the three-terminal switch device method, the average circuit model of the fractional order Buck-Boost converter is established, and the corresponding DC equivalent circuit model and AC small signal equivalent circuit model are presented. And then, the equilibrium point and the transfer functions are derived. It is found that the equilibrium point is not influenced by the inductor's or the capacitor's order, but both these orders are included in the derived transfer functions. Finally, the comparisons between the theoretical analysis and the PSIM simulations are given for confirmation.

  7. Analysis, control and design of a non-inverting buck-boost converter

    DEFF Research Database (Denmark)

    Almasi, Omid Naghash; Fereshtehpoor, Vahid; Khooban, Mohammad Hassan

    2017-01-01

    In this paper, a new modified fuzzy Two-Level Control Scheme (TLCS) is proposed to control a non-inverting buck-boost converter. Each level of fuzzy TLCS consists of a tuned fuzzy PI controller. In addition, a Takagi–Sugeno–Kang (TSK) fuzzy switch proposed to transfer the fuzzy PI controllers...... to each other in the control system. The major difficulty in designing fuzzy TLCS which degrades its performance is emerging unwanted drastic oscillations in the converter output voltage during replacing the controllers. Thereby, the fuzzy PI controllers in each level of TLCS structure are modified...... to eliminate these oscillations and improve the system performance. Some simulations and digital signal processor based experiments are conducted on a non-inverting buck-boost converter to support the effectiveness of the proposed TLCS in controlling the converter output voltage....

  8. Dynamics and stabilization of peak current-mode controlled buck converter with constant current load

    Institute of Scientific and Technical Information of China (English)

    冷敏瑞; 周国华; 张凯暾; 李振华

    2015-01-01

    The discrete iterative map model of peak current-mode controlled buck converter with constant current load (CCL), containing the output voltage feedback and ramp compensation, is established in this paper. Based on this model the com-plex dynamics of this converter is investigated by analyzing bifurcation diagrams and the Lyapunov exponent spectrum. The effects of ramp compensation and output voltage feedback on the stability of the converter are investigated. Experimental results verify the simulation and theoretical analysis. The stability boundary and chaos boundary are obtained under the theoretical conditions of period-doubling bifurcation and border collision. It is found that there are four operation regions in the peak current-mode controlled buck converter with CCL due to period-doubling bifurcation and border-collision bifur-cation. Research results indicate that ramp compensation can extend the stable operation range and transfer the operating mode, and output voltage feedback can eventually eliminate the coexisting fast-slow scale instability.

  9. A Novel Soft-Switching Synchronous Buck Converter for Portable Applications

    Directory of Open Access Journals (Sweden)

    Anup Kumar Panda

    2008-01-01

    Full Text Available This paper proposes a zero-voltage-transition (ZVT pulse-width-modulated (PWM synchronous buck converter, which is designed to operate at low voltage and high efficiency typically required for portable systems. A new passive auxiliary circuit that allows the main switch to operate with zero-voltage switching has been incorporated in the conventional PWM synchronous buck converter. The operation principles and a detailed steady-state analysis of the ZVT-PWM synchronous converter implemented with the auxiliary circuit are presented. Besides, the main switch and all of the semiconductor devices operate under soft-switching conditions. Thus, the auxiliary circuit provides a larger overall efficiency. The feasibility of the auxiliary circuit is confirmed by simulation and experimental results.

  10. Modelling and Simulation of Closed Loop Controlled Buck Converter Fed Pmbldc Drive System

    Directory of Open Access Journals (Sweden)

    R. Dhanasekaran

    2011-04-01

    Full Text Available Permanent Magnet Brushless DC Motor (PMBLDC is one of the best electrical drives that has increasing popularity, due to their high efficiency, reliability, good dynamic response and very low maintenance. This makes the interest of modeling an ideal PMBLDC motor and it’s associated Drive System in simple and lucid manner. In this paper the drive system is proposed with a buck converter topology. It has the advantages of reduced switching losses, low inductor power loss, reduced ripple by using a pi-filter, which in turn makes the DC link voltage to be stable. The modeling and simulation of the PMBLDC motor is done using the software package MATLAB/SIMULINK. The operation principle of the buck converter is analyzed and the simulation results are presented in this paper to verify the theoretical analysis.

  11. Letter to Silverton and San Juan County Regarding Potential Superfund Listing

    Science.gov (United States)

    Feb. 12, 2016 Update: EPA added a letter to the Town of Silverton and San Juan County regarding the agency’s commitment to the Town and County’s involvement during a potential Superfund listing process.

  12. Grain Handling Facility at Freeman, Washington Proposed to Superfund Cleanup List

    Science.gov (United States)

    (March 24, 2015 - Seattle) The U.S. Environmental Protection Agency is proposing to add the Grain Handling Facility at Freeman, in Spokane County, Washington, to the Superfund National Priorities List. The proposed listing includes a 60-day public comment

  13. Non-Inverted Buck-Boost Converters with Dual Delta Sigma Modulators

    Science.gov (United States)

    Kobori, Yasunori; Kono, Masashi; Shimizu, Toshihiko; Kobayashi, Haruo

    This paper presents a new control circuit to create high-performance non-inverted Buck-Boost converter with dual ⊿∑ modulations. Experimental load regulation, corresponding to load current steps of ±0.5A, is within 45mVpp, and the efficiency without synchronized rectifier is 83% at input voltage 2.5V and load current 0.8A.

  14. Incremental Conductance MPPT Algorithm for PV System Implemented Using DC-DC Buck and Boost Converter

    OpenAIRE

    2014-01-01

    The two basic topologies of switch mode DC-DC converters (Buck and Boost) are analyzed with a view of their use in PV (photovoltaic) systems, as the photovoltaic generator exhibits non-linear characteristics due to the change in environmental condition and load variation. As the efficiency of PV panels is low it becomes mandatory to extract maximum power from the PV panel at a given period of time. Several MPPT algorithms with different types of converters are being proposed f...

  15. Buck-Boost/Forward Hybrid Converter for PV Energy Conversion Applications

    OpenAIRE

    2014-01-01

    This paper presents a charger and LED lighting (discharger) hybrid system with a PV array as its power source for electronic sign indicator applications. The charger adopts buck-boost converter which is operated in constant current mode to charge lead-acid battery and with the perturb and observe method to extract maximum power of PV arrays. Their control algorithms are implemented by microcontroller. Moreover, forward converter with active clamp circuit is operated in voltage regulation cond...

  16. Design and realization of the BUCK converter based on anti-saturated PI controller

    Directory of Open Access Journals (Sweden)

    JIANG Lan

    2013-02-01

    Full Text Available A kind of anti-saturated digital PI regulator is designed and implemented based on DSP.This PI regulator was applied to the system design of voltage and current double-loop control in a BUCK converter and related experimental research was made in a 5.5 KW prototype machine.Experimental results show that the converter has good static and dynamic performances and the validity of the design of the PI regulator is verified.

  17. Simulation and Implementation a Non-Isolated Buck Converter at ZCS Condition

    Directory of Open Access Journals (Sweden)

    Nahid Hematian

    2013-10-01

    Full Text Available A new soft-switching resonant inverting-buck converter with high efficiency is presented. The proposed converter steps down and inverts the input voltage. The zero-current-switching (ZCS technique is employed to reduce switching losses and Electromagnetic Interferences (EMI. An LLC resonant network is utilized to provide soft-switching conditions for all semiconductor devices. Experimental results verify the integrity of the proposed converter operation and the presented theoretical analysis.

  18. Informational model verification of ZVS Buck quasi-resonant DC-DC converter

    Science.gov (United States)

    Vakovsky, Dimiter; Hinov, Nikolay

    2016-12-01

    The aim of the paper is to create a polymorphic informational model of a ZVS Buck quasi-resonant DC-DC converter for the modeling purposes of the object. For the creation of the model is applied flexible open standards for setting, storing, publishing and exchange of data in distributed information environment. The created model is useful for creation of many and different by type variants with different configuration of the composing elements and different inner model of the examined object.

  19. Level of nutrition affects semen characteristics and freezability of Malaysian bucks

    Directory of Open Access Journals (Sweden)

    Abdullah*, R. B.

    2015-06-01

    Full Text Available Feeding is a major problem in goat production in Malaysia particularly it affects reproductive efficiency of goats. This research was aimed to confirm the effect of improper nutrition and management practice on the buck?s fresh and frozen-thawed semen quality. Bucks were challenged nutritionally by the standard feeding (standard-nutrition and underfeeding (under-nutrition, i.e. inadequate daily requirement of Napier grass (Pennisetum purpureum and pelleted compound feed. Bucks from three different breeds (Jermasia n=4, Boer n=1 and Katjang n=1 were used for semen collection and semen freezing. The fresh semen quality was used as control. Fresh semen qualities, i.e. volume (ml/ejaculate, mass movement, concentration (?109/ml and motility (% were 0.48, 3.92, 3.97, 82.5 for Jermasia, 0.62, 4.00, 4.20, 86.00 for Boer, 0.55, 3.5, 5.35, 87.50 for Katjang, respectively while the values for frozen-thawed sperm motility for Jermasia, Boer and Katjang were 55.83, 66.00 and 67.50%, respectively. In comparison of the different nutritional regimes, for fresh semen qualities, i.e. volume (ml/ejaculate, mass movement, concentration (?109/ml and motility (% were 0.56, 4.00, 4.34 and 86.00 for standard-nutrition and 0.38, 3.50, 3.57 and 76.25 for under-nutrition, respectively, while the values for frozen-thawed sperm motility for standard-and under-nutrition were 63.33 and 46.25%, respectively. It is imperative that adequate nutrients in proper feeding be given serious attention to ensure the success of semen collection and semen freezing.

  20. Perancangan dan Simulasi Full Bridge Inverter Lima Tingkat dengan Dual Buck Converter Terhubung Jaringan Satu Fasa

    Directory of Open Access Journals (Sweden)

    Zamratul Fuadi

    2014-03-01

    Full Text Available Inverter merupakan perangkat elektronika daya yang berfungsi mengonversi sumber searah menjadi bolak-balik. Full bridge inverter adalah satu jenisnya yang mampu menghasilkan tegangan tiga tingkat jika menggunakan teknik modulasi unipolar. Penambahan sirkuit dual buck converter pada full bridge inverter mampu menghasilkan tegangan dalam lima tingkat. Dua saklar pada rangkaian dual buck converter switching pada frekuensi tinggi 20 kHz, sedangkan empat saklar pada full bridge inverter switching pada frekuensi rendah 50 Hz. Teknik modulasi in phase disposition PWM (PDPWM digunakan untuk mengatur penyalaan saklar dual buck converter. Keluaran inverter lima tingkat dibandingkan dengan tiga tingkat. Total harmonic distortion tegangan (THDV dan arus (THDi inverter lima tingkat bernilai 23.2281 % dan 23.0975 %, sedangkan inverter tiga tingkat sebesar 51.9302 % dan52.2458 %. Ketika daya 1004.08 watt disumbangkan ke jala-jala, inverter lima tingkat menghasilkan power factor senilai 0.99 dan THDi 4.1 %. Pada sumbangan daya yang sama, inverter tiga tingkat menghasilkan power factor sebesar 0.919 dan THDi bernilai 45.64 %.

  1. Whole-body Response for Pedestrian Impact with a Generic Sedan Buck.

    Science.gov (United States)

    Forman, Jason L; Joodaki, Hamad; Forghani, Ali; Riley, Patrick O; Bollapragada, Varun; Lessley, David J; Overby, Brian; Heltzel, Sara; Kerrigan, Jason R; Crandall, Jeff R; Yarboro, Seth; Weiss, David B

    2015-11-01

    To serve as tools for assessing injury risk, the biofidelity of whole-body pedestrian impact dummies should be validated against reference data from full-scale pedestrian impact tests. To facilitate such evaluations, a simplified generic vehicle-buck has been recently developed that is designed to have characteristics representative of a generic small sedan. Three 40 km/h pedestrian-impact tests have been performed, wherein Post Mortem Human Surrogates (PMHS) were struck laterally in a mid-gait stance by the buck. Corridors for select trajectory measures derived from these tests have been published previously. The goal of this study is to act as a companion dataset to that study, describing the head velocities, body region accelerations (head, spine, pelvis, lower extremities), angular velocities, and buck interaction forces, and injuries observed during those tests. Scaled, transformed head accelerations exceeded 80 g prior to head contact with the windshield for two of the three tests. Head xaxis angular velocity exceeded 40 rad/s prior to head contact for all three tests. In all cases the peak resultant head velocity relative to the vehicle was greater than the initial impact speed of the vehicle. Corridors of resultant head velocity relative to the vehicle were also developed, bounded by the velocities observed in these tests combined with those predicted to occur if the PMHS necks were perfectly rigid. These results, along with the other kinematic and kinetic data presented, provide a resource for future pedestrian dummy development and evaluation.

  2. In vivo adverse effects of alpha-tocopherol on the semen quality of male bucks.

    Science.gov (United States)

    Majid, A; Qureshi, M S; Khan, R U

    2015-10-01

    Oxidative stress has detrimental effects on semen quality during spermatogenesis and semen processing for artificial insemination. This work was conducted to study the effect of different levels of vitamin E on the semen traits, oxidative status and trace minerals in Beetal bucks. Thirty-six bucks of similar body weight and age (1 year) were randomly divided into four groups. One group was kept as control with no supplementation (group 1), and the others were supplemented with 200 (group 2), 400 (group 3) and 800 IU (group 4) vitamin E/animal/day for 2 months. At the end of the experiment, semen samples were collected and evaluated. Seminal plasma was separated to study the concentration of superoxide dismutase (SOD), glutathione peroxidase (GPx), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and trace minerals (Zn, Cu, Mn and Fe). Group 3 showed significantly higher (p Zn, Cu and Mn were higher in the same group. The level of AST decreased in group 3 without any change on the concentration of ALT. It is suggested that vitamin E at the rate of 400 IU/buck/day supported higher semen volume, per cent motility, per cent live spermatozoa, antioxidants (SOD, GPx) and trace mineral levels (Zn, Cu, Mn) in the seminal plasma. The increased supplementation from 0 to 400 showed a general increasing trend in improving semen quality. However, the dose of 800 IU/kg had no useful effect in further improving the semen quality.

  3. Buck-Boost变换器的环路补偿及仿真%Loop Compensation and Simulation of Buck-Boost Converter

    Institute of Scientific and Technical Information of China (English)

    于月森; 戚文艳

    2014-01-01

    设计DC-DC变换器时为了使其满足静态和动态指标的要求,一般需要设计良好的补偿网络,而变换器输出滤波电容的等效串联电阻ESR对补偿网络的影响是不可忽略的.为了探究等效串联电阻对补偿网络的影响,该文采用波特图法对工作在连续工作模式(CCM模式)下的Buck-Boost变换器的稳定性进行分析,并讨论了有无ESR时补偿器的设计方案,结果显示ESR不同,选用的补偿方案也不同;然后利用Matlab工具对补偿后的Buck-Boost变换器进行仿真,验证补偿网络设计的正确性.

  4. PT controlled PCCM Buck-Boost converter with two control variables%两控制变量PT控制PCCM Buck-Boost变换器

    Institute of Scientific and Technical Information of China (English)

    秦明; 李芳芳

    2016-01-01

    为减小电感惯性模态期间电感电流下降对下一周期脉冲的影响,根据伪连续导电模式(Pseudo ContinuousConduction Mode,PCCM) Buck-Boost变换器的工作特点,提出一种新的脉冲序列(Pulse Train,PT)控制策略.控制策略中包含两个控制变量,使控制器根据不同能量的电压控制脉冲产生不同的电流控制脉冲.详细分析了新型PT控制策略下PCCM Buck-Boost变换器的工作过程,给出了高低能量电压控制脉冲比.仿真与实验结果验证了新型控制策略的可行性及理论分析的正确性.

  5. Half Load-Cycle Worked Dual Buck-Boost Single-Stage Inverter%半周控制双Buck-Boost单级逆变器

    Institute of Scientific and Technical Information of China (English)

    嵇保健; 洪峰

    2011-01-01

    本文提出了一种新颖的双Buck-Boost单级逆变器。单级式逆变器相比传统的两级式逆变器,拓扑结构大大简化,减小了体积重量,降低了损耗,在中小功率场合中的应用具有明显的优势。同时传统单级逆变器不能直接实现升压逆变,在输入母线电压较低时必须增加前级升压电路。针对以上情况,本文通过将两个Buck-Boost电路采用输入串联、输出并联的方式组合,得到一种新型的双Buck-Boost逆变器,并采用半周工作方式使其正常可靠工作,可实现单级直接升压逆变。文中对该电路的工作原理和控制策略进行了详细的分析。仿真和实验验证了新型电路的可行性。该电路在输入母线电压低于输出电压的宽电压范围内均能正常逆变,并取得了较好的波形质量和较高的变换效率。%A novel half load-cycle worked dual Buck-Boost single-stage inverter is presented in this paper.Compared with the traditional two-stage inverter,the single-stage inverter is smaller and lighter due to the structure is greatly simplified as well as the circuit components are reduced a lot.Direct boost DC-AC converter can not be realized by most traditional inverter,so one DC-DC converter has to be added in the front of traditional inverter when input bus voltage is low.In order to obtain one single-stage inverter which can make direct boost inverter come true,two Buck-Boost topologies are combined which are series-wound in input side and parallel connected in output side.Special half load-cycle control mode is used in this new inverter.No matter the input bus voltage is higher or lower than the output voltage,the new inverter works normally and reliably and the output waveform is good,the converter efficiency is high at the same time.Simulation and Experiment verifies those analysis.

  6. Site Enforcement Tracking System (SETS): PRP listing by site for Region 9

    Energy Technology Data Exchange (ETDEWEB)

    1992-07-01

    When expending Superfund monies at a CERCLA (Comprehensive Environmental Response, Compensation and Liability Act) site, EPA must conduct a search to identify parties with potential financial responsibility for remediation of uncontrolled hazardous waste sites. EPA regional Superfund Waste Management Staff issue a notice letter to the potentially responsible party (PRP). Data from the notice letter is used to form the Site Enforcement Tracking System (SETS). This data includes PRP name and address, a company contact person, the date the notice was issued, and the related CERCLA site name and identification number. SETS was created to track PRP identification at both NPL (National Priorities List) and non-NPL sites. SETS does not address the range of other administrative duties related to tracking the PRP. Region 9 includes American Samoa, Arizona, California, Guam, Hawaii, Midway, Nevada, Northern Marianas, Pacific Islands, Trust Territories, and Wake Island.

  7. Homosexual behavior in male goats is more frequent during breeding season and in bucks isolated from females.

    Science.gov (United States)

    Ungerfeld, Rodolfo; Giriboni, Julia; Freitas-de-Melo, Aline; Lacuesta, Lorena

    2014-05-01

    Male homosexual behavior is observed in many ruminant species; seasonality and isolation from females may affect the display of male-male sexual behavior. Our objectives were to determine whether: 1) homosexual behavior has a seasonal pattern in male goats (Capra hircus); 2) isolation from female goats influences the frequency of the display of homosexual behavior; and 3) the frequency of homosexual behaviors is related to testosterone concentration. Bucks were housed in a pen adjacent to another pen with 3 estrous goats (FC group) or in complete isolation from females (IF group). Homosexual behaviors and testosterone concentrations were recorded in October, December, February and May. Frequencies of penile display and flehmen increased in May and were observed more frequently in the IF than in the FC group. Ano-genital sniffing was more frequent in February and May and was more frequent in IF than in FC bucks. Lateral approaches were more frequent in May, in which period this was more frequently observed in IF bucks. Mount attempts and mounts were only observed in IF bucks. Testosterone concentrations increased from December to February and decreased in May, although they were still greater than in October and December. In May IF bucks had greater testosterone concentrations than FC bucks. Testosterone concentrations were only related to the number of lateral approaches in IF bucks in December. In conclusion, homosexual behavior was more frequent during the late breeding season than during the early and the non-breeding seasons, and in males isolated from females than in males housed near estrous females. Testosterone concentrations appear to be unrelated to homosexual behavior.

  8. Phytoextraction of Pb and Cd from a superfund soil: effects of amendments and croppings.

    Science.gov (United States)

    Bricker, T J; Pichtel, J; Brown, H J; Simmons, M

    2001-01-01

    In a growth chamber, maize (Zea mays) and Indian mustard (Brassica juncea) were grown over two croppings in soil from a Superfund site (PbTotal = 65,200 mg/kg and CdTotal = 52mg/kg). Soil treatments consisted of ethylenediaminetetraacetic acid, sodium citrate and composted sewage sludge, each at two rates (EDTA .05%, EDTA .2%, citrate .05%, citrate .2%, CSS 5% and CSS 10%, respectively). In most cases, the EDTA and citrate treatments were superior in terms of solubilizing soil Pb for root uptake and translocation into above-ground biomass. In the first maize crop, the EDTA .2% treatment resulted in 2,435 and 9,389mg/kg Pb in shoot and root tissues, respectively. The CSS treatments typically resulted in lowest Pb and Cd removal efficiencies. Lead remaining in the soil after two croppings was mainly associated with the carbonate, organic, and residual fractions, which represent the less bioavailable forms. Soil Cd was generally more mobile for plant uptake than soil Pb. The EDTA .2% and citrate treatments were most successful in promoting Cd uptake by both maize and mustard. Although Pb concentrations (mg/kg tissue) were lower for maize than mustard, the former removed more total Pb (0.2 mg per pot, mean over all treatments), compared to mustard (0.03 mg), by virtue of its higher biomass production.

  9. Superfund record of decision (EPA Region 9): McClellan Air Force Base, Basewide Groundwater Operable Unit, Sacramento, CA, May 11, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    The Interim Record of Decision (ROD) presents the interim remedial action for the Groundwater Operable Unit (Groundwater OU) at the McClellan Air Force Base (McClellan AFB) Superfund site in Sacramento, California. The Groundwater OU addresses all of the VOC-contaminated groundwater at McClellan AFB. The Groundwater OU remedy is designed to prevent the spread of contamination that is already in the groundwater by containing groundwater with concentrations greater than maximum contaminant levels (MCLs). The remedy is also designed to remove to the maximum extent practicable the mass of contamination that lies in that volume of the groundwater.

  10. 一种非反相Buck-Boost功率变换器的调制方法研究%Research on Modulation Method for Non-inverting Buck-Boost Power Converter

    Institute of Scientific and Technical Information of China (English)

    徐坤; 杨宇; 吴春华; 许富强

    2011-01-01

    针对功率变换器现有调制方法的不足,提出了一种用于非反相Buck-Boost功率变换器的调制方法,结合脉冲宽度调制和脉冲频率调制,使该功率变换器平滑地在Buck、Buck-Boost、Boost三种模式之间切换,从而在输入电压低于、高于或近似等于输出电压给定值的情况下,使输出电压稳定在给定电压.试验结果验证了该算法的可行性和有效性.%Aiming at the drawbacks of modulation method for power converter, a modulation method which combines pulse width modulation (PWM) with pulse frequency modulation (PFM) for the non-inverting buck-boost converter is proposed in the paper.The power converter can switch smoothly among buck working mode, buck boost working mode and boost working mode in order to regulate the output voltage to the desired output voltage regardless of that the input voltage is less than, greater than or equal to the desired output voltage.The experimental results verify the feasibility and efficiency of the proposed algorithm.

  11. Improving fruit and vegetable consumption among low-income customers at farmers markets: Philly Food Bucks, Philadelphia, Pennsylvania, 2011.

    Science.gov (United States)

    Young, Candace R; Aquilante, Jennifer L; Solomon, Sara; Colby, Lisa; Kawinzi, Mukethe A; Uy, Nicky; Mallya, Giridhar

    2013-10-03

    We evaluated whether Philly Food Bucks, a bonus incentive program at farmers markets, is associated with increased fruit and vegetable consumption and Supplemental Nutrition Assistance Program (SNAP) sales at farmers markets in low-income areas. A convenience sample of 662 customers at 22 farmers markets in low-income neighborhoods in Philadelphia, Pennsylvania, was surveyed via face-to-face interviews. Questions addressed shopping characteristics, self-reported change in fruit and vegetable consumption, whether customers tried new fruits or vegetables, use of Philly Food Bucks, and demographic information. Market-level SNAP sales and Philly Food Bucks redemption data were also collected to monitor sales patterns. Philly Food Bucks users were significantly more likely than nonusers to report increasing fruit and vegetable consumption (OR, 2.4; 95% CI, 1.6-3.7; P Food Bucks program. At the city's largest farmers market in a low-income area, the program was associated with an almost 5-fold higher increase in annual SNAP sales compared with baseline. Results from this study demonstrate that a bonus incentive program tied to SNAP was associated with self-reported increases in fruit and vegetable consumption and increased SNAP sales at participating farmers markets in low-income communities. More research is warranted to evaluate the long-term impact of bonus incentives on farmers market use, dietary behaviors, and health outcomes.

  12. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 (Version 2.1) Catchments Riparian Buffer for the Conterminous United States: Facility Registry Services (FRS) : Toxic Release Inventory (TRI) , National Pollutant Discharge Elimination System (NPDES) , and Superfund Sites

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents the estimated density of georeferenced sites within individual, local NHDPlusV2 catchments and upstream, contributing watersheds riparian...

  13. Analysis of Bifurcation in Marine Current-mode Controlled Buck-boost Converter%船用电流控制型Buck-boost变换器分岔行为分析

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    为了分析船用电流控制型Buck-boost变换器的分岔非线性动力学行为,首先推导一种描述船用Buck-boost变换器分岔行为演化过程的非线性迭代映射模型,然后采用雅可比矩阵来确定Buck-boost变换器首次出现失稳的分岔点,最后进行了不同分岔参数的仿真试验.仿真试验结果表明了理论推导模型的正确性,并且可有效预测首次出现的分岔点.

  14. 混沌态电流模式Buck-Boost开关变换器的OGY控制%OGY Control of the Chaotic Current Mode Buck-Boost Switching Converter

    Institute of Scientific and Technical Information of China (English)

    王利清; 魏学业; 温伟刚; 谢涛

    2005-01-01

    从电流模式Buck-Boost开关变换器周期-1状态的频闪采样离散时间迭代映射数学模型出发,提出了一种混沌态电流模式Buck-Boost开关变换器吸引子中不稳定周期-1轨道的确定方法.根据OGY控制的原理和思想,推导出OGY控制矢量的取值范围,以此为依据选择控制矢量,实现了对混沌态的电流模式Buck-Boost开关变换器相空间中的一条不稳定周期-1轨道的稳定控制.

  15. 基于Buck-Boost变换器的T-S模糊建模和仿真研究%T-S fuzzy modeling and simulation of Buck-Boost converter

    Institute of Scientific and Technical Information of China (English)

    王艳; 吴正成; 纪志成

    2008-01-01

    根据Buck-Booat变换器的工作原理及其非线性特征,在电感电流连续导通模式和断续导通模式下,分别对Buck-Boost 电路构建T-S模糊模型,在断续导通模式下,引入切换函数,统一了两种模式下电路状态方程和T-S模糊模型.仿真结果表明,Buck-Boost变换器经T-S建模后,输出电压平均值和电感电流的平均值的误差均在2%以内,符合实际应用的要求.T-S模糊建模的有效性和可行性得到验证.

  16. Pengaruh Pencucian Sperma dengan Lama Waktu Sentrifugasi yang Berbeda Terhadap Kualitas Sperma Kambing Bligon (Effect of Sperm Washing with Different Centrifugation Duration on Sperm Quality of Bligon Buck

    Directory of Open Access Journals (Sweden)

    Sigit Bintara

    2012-02-01

    spermatozoa. It is concluded that washing Bligon buck sperm using SpermRinse with centrifugation at 1.500 rpm (r = 5.5 cm could increased sperm quality, of which 20 minutes was the best centrifugation time. (Key word: Bligon Buck, Sperm, SpermRinse, Sperm quality

  17. Analyses of Buck-Boost Converter Based on the Principle of Volt-second Balance%基于伏秒平衡原理的Buck-Boost变换器分析

    Institute of Scientific and Technical Information of China (English)

    王学梅; 易根云; 丘东元; 张波

    2012-01-01

    针对现有"电力电子技术"教材中普遍存在的对Buck-Boost变换器的分析不完整等问题,本文基于伏秒平衡原理对Buck-Boost变换器进行了全面分析,推导出变换器全范围的输入输出电压关系,电流连续模式(CCM)和断续模式(DCM)的临界工作条件以及电路各参数对电流纹波和电压纹波的影响等。本文一方面有助于更全面深入地理解Buck-Boost变换器的工作原理及特性,另一方面有助于DC-DC变换器分析方法的统一,具有一定的教学指导意义。%There are some incomplete analyses of buck-boost converters in current materials of power electronics. Based on the principle of volt-second balance, this paper analyzes the buck-boost converter comprehensively. Next, the ratio of input and output voltage in full range is derived, and the critical working conditions in continuous conduction mode and discontinuous conduction mode are analyzed. Last, the effects of circuit parameters on current and voltage rip- ple are illustrated. On the one hand, this paper can help to understand thoroughly the operating principle of buck-boost converter, and on the other hand, it also can help to analyses DC-DC converters uniformly, which has certain signifi- cance in the teachings of power electronics.

  18. BUCK-BOOST DC/DC变换器RHP零点研究%Right Half Plane Zero Spot Research of BUCK-BOOST DC/DC Converter

    Institute of Scientific and Technical Information of China (English)

    周习祥

    2010-01-01

    对于BUCK-BOOST DC/DC变换器,如何获得较大的稳定裕度和良好的高频瞬态性能一直以来都是令研究人员棘手的问题.要使这种变换器稳定工作,往往需要在一个很低的频率下就滑离控制电路的增益,文章基于变换器的占空比控制方式与电流控制公式分析了右半平面零点的动态特性,为提高电源系统的稳定性提供了理论依据.

  19. 新颖的Buck-Boost高频环节AC/AC变换器%Novel Buck-Boost AC/AC Converters with High Frequency Link

    Institute of Scientific and Technical Information of China (English)

    刘剑; 陈道炼; 尹春

    2004-01-01

    提出了Buck-Boost高频环节AC/AC变换器电路拓扑,该电路拓扑由输入周波变换器、高频储能式变压器、输出周波变换器构成.分析研究了该变换器工作模式和电压瞬时值反馈控制策略.理论分析和试验表明,该变换器具有两级功率变换(LFAC/HFAC/LFAC)、双向功率流、网侧电流波形可得到改善、负载适应能力强、音频噪音小等优点.

  20. 高动态响应的Buck-Boost变换器的边界控制%Boundary Control of Buck-Boost Converter with Fast Response

    Institute of Scientific and Technical Information of China (English)

    马朋; 陆益民

    2007-01-01

    应用状态轨迹预测的方法,调节Buck-Boost变换器电压输出.根据在一个假定的开关动作后预测电压输出,设计二阶开关面,在一个开关周期内就可引导系统轨迹到达目标工作点,具有大信号稳定性,对负载扰动及电源扰动均有很强的自适应性,通过仿真验证了理论的正确性.

  1. 级联Buck-Boost PFC变换器建模及仿真%Modeling and Simulation of Cascaded Buck-Boost AC-DC Converter

    Institute of Scientific and Technical Information of China (English)

    郭学军; 刘以建

    2016-01-01

    文中采用状态空间平均法对级联Buck-Boost AC-DC变换器进行了小信号建模分析,提出了一种基于瞬时功率守恒的新的平均电流控制(ACC)技术.通过这种新的控制技术能够使得输入电流波形接近正弦波且与输入电压同相位,总的谐波扰动小于3%.最后通过PSIM仿真实验,验证了这种新的控制方法的可行性和优越性.

  2. ANAEROBIC COMPOST CONSTRUCTED WETLANDS SYSTEM TECHNOLOGY - SITE TECHNOLOGY CAPSULE

    Science.gov (United States)

    In fall 1994, anaerobic compost wetlands in both upflow and down flow configurations were constructed adjacent to and received drainage from the Burleigh tunnel, which forms part of the Clear Creek/Central City Superfund site. The systems were operated over a 3 year period. The ...

  3. ANAEROBIC COMPOST CONSTRUCTED WETLANDS SYSTEM TECHNOLOGY - SITE ITER

    Science.gov (United States)

    In Fall 1994, anaerobic compost wetlands in both upflow and downflow configurations were constructed adjacent to and received drainage from the Burleigh Tunnel, which forms part of the Clear Creek/Central City Superfund site. The systems were operated over a 3 year period. The e...

  4. ANAEROBIC COMPOST CONSTRUCTED WETLANDS SYSTEM TECHNOLOGY - SITE TECHNOLOGY CAPSULE

    Science.gov (United States)

    In fall 1994, anaerobic compost wetlands in both upflow and down flow configurations were constructed adjacent to and received drainage from the Burleigh tunnel, which forms part of the Clear Creek/Central City Superfund site. The systems were operated over a 3 year period. The ...

  5. ANAEROBIC COMPOST CONSTRUCTED WETLANDS SYSTEM TECHNOLOGY - SITE ITER

    Science.gov (United States)

    In Fall 1994, anaerobic compost wetlands in both upflow and downflow configurations were constructed adjacent to and received drainage from the Burleigh Tunnel, which forms part of the Clear Creek/Central City Superfund site. The systems were operated over a 3 year period. The e...

  6. Active battery charge equalization with voltage controlled vertical buck-boost switching cells%电压控制Buck-Boost电池充电均衡器

    Institute of Scientific and Technical Information of China (English)

    谢莉; 蒋伟

    2015-01-01

    本文研究了储能设备的均衡充电方法。采用垂直 Buck-Boost 电路作为均衡器的基本交换单元。在不同的负载条件下,用状态空间平均法和小信号分析法获得对应的开关单元模型。通过电压控制均衡方案,利用电压环补偿设备端电压,电流内环使得电荷定向移动。实验结果表明,所提出的均衡器能实现电荷最快移动并能有效地收敛到零电压差,本地控制器能快速、准确地跟踪参考值。%This paper investigates the active charge equalization method for energy storage devices. The vertical buck-boost circuit is used as the basic switching cell of this equalizer. By applying state-space averaging and small signal analysis, the model of the switching cell is obtained under different load condition. A voltage controlled equalization scheme is presented, which is featured with voltage loop to equalize the terminal voltage and inner current loop for charge shuttling. The simulation and experimental results indicate that the proposed equalizer can effectively converge to zero voltage difference condition by offering a maximized charge shuttling effort, and the local controller can react fast and precisely to the reference command.

  7. 电流反馈型Buck-Boost变换器的非线性动力学研究%STUDY ON NONLINEAR DYNAMICS BEHAVIORS BASED ON CURRENT-PROGRAMMED BUCK-BOOST CONVERTER

    Institute of Scientific and Technical Information of China (English)

    赵益波; 罗晓曙; 唐国宁; 翁甲强

    2005-01-01

    首先建立了电流反馈型buck-boost变换器的精确离散化模型,然后研究了变换器在不连续模式下的非线性动力学行为.通过研究发现:电流反馈型Buck-Boost变换器在不连续模式下,出现了特有的分岔和混沌现象.

  8. Development and implementation of fuzzy logic using microcontroller for buck and boost DC-to-DC converter

    Science.gov (United States)

    Lorenzo, J., Jr.; Espiritu, J. C.; Mediavillo, J.; Dy, S. J.; Caldo, R. B.

    2017-06-01

    This paper aims to develop and implement a Sugeno-style fuzzy inference system using a microcontroller for buck and boost DC-to-DC converter. The buck converter circuit is given an input voltage range of 4-5V and expected to have an output voltage of 1.5V, while the boost converter has an input voltage range of 2-3V and expected to have an output voltage of 15V. A microcontroller will be used for the input values, PWM signal, which is supplied through the MOSFET. The constants in the program in the microcontroller were manipulated to acquire desired accurate output voltages wherein the concept of fuzzy logic was applied. The proponents achieved less than 2.5% tolerance in the buck converter and less than 5% in the boost converter.

  9. A New Buck-Boost Converter for a Hybrid-Electric Drive Stand

    Directory of Open Access Journals (Sweden)

    P. Mašek

    2009-01-01

    Full Text Available This paper describes work on the laboratory working stand for a hybrid-electric drive located in laboratory T2:H1-26.The basic idea is to operate the combustion engine in its optimal regime. In this regime the engine has the highest efficiency and minimal smoke exhaust. This optimal regime is only a small portion of its operation area. Because the engine has to operate in this area, it is necessary to add a new converter to the hybrid-electric stand. The new converter must be allowed to buck and boost and must operate as a current source in this regime. 

  10. Evaluation of Arm Processor-based Bionic Intelligent Controller for a Buck-boost Converte

    Directory of Open Access Journals (Sweden)

    M.V. Mini

    2015-07-01

    Full Text Available This study focuses on performance-comparison of different tuning methods for a PI controller applied to a buck-boost converter. Comparison between the controllers is made by analysis of design methodology implementation issues and empirically measured performance. Design of PI controller is based on frequency response of the converter. The optimization of PI controller is based on ant colony algorithm. Experimental results show that, tuning the PI controller using ACO algorithm gave better performance than the conventional algorithm. This is mainly due to the fact ACO is capable of reducing the overshoot without oscillation.

  11. Analysis and design of an adaptive multi-loop controlled two winding buck/boost regulator

    Science.gov (United States)

    Mahmoud, M. F.; Lee, F. C.

    1979-01-01

    Small signal low frequency linear average model is derived for a multi-loop controlled two-winding buck/boost converter employing average techniques and the describing function method. The model reveals that a well-designed multi-loop control can provide a second-order zero adaptive to output filter parameter changes due to component tolerances, temperature changes, aging, and the effect of duty cycle modulation. It also can provide stabilization effect by shifting the positive zero to the left-half S-plane. Design guidelines are formulated to optimize regulator-loop dependent characteristics.

  12. A New Approach for High Efficiency Buck-Boost DC/DC Converters Using Series Compensation

    Science.gov (United States)

    Itoh, Jun-Ichi; Fujii, Takashi

    This paper proposes a novel concept for non-isolated buck-boost DC/DC converter and control method. The proposed concept uses a series connection converter that only regulates the differential voltage between the input and output voltage. As a result, the power converter capacity is decreased. Moreover, the proposed circuit has advantages such as improved efficiency and losses reduction. The fundamental operation, control method, and design method of the proposed circuit are described in this paper. In addition, the validity of the proposed circuit is confirmed by carrying out simulations and experiments.

  13. A novel single phase buck PFC converter in discontinuous capacitor voltage mode operation

    Institute of Scientific and Technical Information of China (English)

    邓超平; 凌志斌; 叶芃生

    2003-01-01

    A novel single-phase Buck converter for power factor correction is proposed. It features simple control due to the constant duty ratio PWM used. It can obtain unity power factor by selecting a suitable LC filter at its input to force the voltage of capacitor to operate in discontinuous capacitor voltage mode. And by using another resonant LC filter at its output, it can not only eliminate the input current distortion at the vicinity of the zero crossing of the supply but also drastically reduce the 100 Hz output voltage ripple. The validity of analysis is confirmed by simulation results and experimental results.

  14. On Some Extensions of Szasz Operators Including Boas-Buck-Type Polynomials

    Directory of Open Access Journals (Sweden)

    Sezgin Sucu

    2012-01-01

    Full Text Available This paper is concerned with a new sequence of linear positive operators which generalize Szasz operators including Boas-Buck-type polynomials. We establish a convergence theorem for these operators and give the quantitative estimation of the approximation process by using a classical approach and the second modulus of continuity. Some explicit examples of our operators involving Laguerre polynomials, Charlier polynomials, and Gould-Hopper polynomials are given. Moreover, a Voronovskaya-type result is obtained for the operators containing Gould-Hopper polynomials.

  15. Single stage buck-boost DC-AC neutral point clamped inverter

    DEFF Research Database (Denmark)

    Mo, Wei; Loh, Poh Chiang; Andrew, A.;

    2012-01-01

    This paper proposes a new single stage buck-boost DC-AC neutral point clamped inverter topology which integrates the cascaded configurations of recently introduced inductor-capacitor-capacitor-transformer impedance source network (by Adamowicz) and classic NPC configuration. As a consequence...... windings thus preventing the core from saturation; lowers the voltage stresses and power losses of inverter switches and reduces the sizes of filtering devices and as well as obtains better output performance compared to the original two-level Z-source inverters. A phase disposition pulse width modulation...

  16. Analysis and design of an adaptive multi-loop controlled two winding buck/boost regulator

    Science.gov (United States)

    Mahmoud, M. F.; Lee, F. C.

    1979-01-01

    Small signal low frequency linear average model is derived for a multi-loop controlled two-winding buck/boost converter employing average techniques and the describing function method. The model reveals that a well-designed multi-loop control can provide a second-order zero adaptive to output filter parameter changes due to component tolerances, temperature changes, aging, and the effect of duty cycle modulation. It also can provide stabilization effect by shifting the positive zero to the left-half S-plane. Design guidelines are formulated to optimize regulator-loop dependent characteristics.

  17. Non-Smooth Bifurcation and Chaos in a DC-DC Buck Converter

    Institute of Scientific and Technical Information of China (English)

    QIN Zhi-Ying; LU Qi-Shao

    2007-01-01

    A direct-current-dorect-current (DC-DC)buck converter with integrated load current feedback is studied with three kinds of Poicaré maps.The external corner-collision bifurcation occurs when the crossing number per period varies,and the internal corner-collision bifurcations occur along with period-doubling and period-tripling bifurcations in this model.The multi-band chaos roots in external corner-collision bifurcation and often grows into l-band chaos.A new kind of chaotic sliding orbits,which is more complex for non-smooth systems,is also found in this model.

  18. Bucking Coil Implementation on PMT for Active Cancelling of Magnetic Field

    CERN Document Server

    Gogami, T; Bono, J; Baturin, P; Chen, C; Chiba, A; Chiga, N; Fujii, Y; Hashimoto, O; Kawama, D; Maruta, T; Maxwell, V; Mkrtchyan, A; Nagao, S; Nakamura, S N; Reinhold, J; Shichijo, A; Tang, L; Taniya, N; Wood, S A; Ye, Z

    2013-01-01

    Aerogel and water Cerenkov detectors were employed to tag kaons for a lambda hypernuclear spectroscopic experiment which used the (e,e'K+) reaction in experimental Hall C at Jefferson Lab (JLab E05-115). Fringe fields from the kaon spectrometer magnet yielded ~5 Gauss at the photomultiplier tubes (PMT) for these detectors which could not be easily shielded. As this field results in a lowered kaon detection efficiency, we implemented a bucking coil on each photomultiplier tubes to actively cancel this magnetic field, thus maximizing kaon detection efficiency.

  19. A Simple Method for Reducing the Transient Oscillation in Single-Phase Buck Rectifiers

    Science.gov (United States)

    Wakakuwa, Yukihiro; Motegi, Shin-Ich; Yoshida, Toshiya; Miyashita, Osamu

    The single-phase buck rectifier has several advantages, such as the controllability of lower dc output voltages, and negligible inrush input-current at start-up. However, the rectifier requires an LC-filter connected on the input side of the switching device to absorb the harmonics caused by the on and off behavior. The LC-filter involves an LC resonance in transient states. To solve this problem, a suppression approach using only a series RLC circuit, which selectively acts as a damping at around the resonant frequency, is proposed. Simulation and experimental results confirm the validity of this method.

  20. Analysis of current-bidirectional buck-boost based switch-mode audio amplifier

    DEFF Research Database (Denmark)

    Bolten Maizonave, Gert; Andersen, Michael A. E.; Kjærgaard, Claus

    2011-01-01

    The following studdy was carried out in order to assses quantitatively the performannce of the buck--boost converter whhen used as swiitch-mode audio amplifier. It comprises of, to beggin with, the de limitation of design criteria bassed on the state of-the-art solution, which is based...... in a differential mode buckbased amplifier with a boost converter as power supply. The averaged switch modelling of the differential mode current bidirectional topology is also used, in order to analyze the steady state and frequency-wise behaviour of this converter and parameterize it to meet the design criteria...... in such configuration when applied for audio....

  1. Sensorless load torque estimation and passivity based control of buck converter fed DC motor.

    Science.gov (United States)

    Kumar, S Ganesh; Thilagar, S Hosimin

    2015-01-01

    Passivity based control of DC motor in sensorless configuration is proposed in this paper. Exact tracking error dynamics passive output feedback control is used for stabilizing the speed of Buck converter fed DC motor under various load torques such as constant type, fan type, propeller type, and unknown load torques. Under load conditions, sensorless online algebraic approach is proposed, and it is compared with sensorless reduced order observer approach. The former produces better response in estimating the load torque. Sensitivity analysis is also performed to select the appropriate control variables. Simulation and experimental results fully confirm the superiority of the proposed approach suggested in this paper.

  2. Sensorless Load Torque Estimation and Passivity Based Control of Buck Converter Fed DC Motor

    Directory of Open Access Journals (Sweden)

    S. Ganesh Kumar

    2015-01-01

    Full Text Available Passivity based control of DC motor in sensorless configuration is proposed in this paper. Exact tracking error dynamics passive output feedback control is used for stabilizing the speed of Buck converter fed DC motor under various load torques such as constant type, fan type, propeller type, and unknown load torques. Under load conditions, sensorless online algebraic approach is proposed, and it is compared with sensorless reduced order observer approach. The former produces better response in estimating the load torque. Sensitivity analysis is also performed to select the appropriate control variables. Simulation and experimental results fully confirm the superiority of the proposed approach suggested in this paper.

  3. Reliability-Oriented Optimization of the LC Filter Design of a Buck DC-DC Converter

    DEFF Research Database (Denmark)

    Liu, Yi; Huang, Meng; Wang, Huai

    2017-01-01

    Lifetime is an important performance factor in the reliable operation of power converters. However, the state-of-the-art LC filter design of a buck DC-DC converter is limited to the specifications of voltage and current ripples and constrains in power density and cost without reliability...... considerations. This paper proposes a method to optimize the design of the LC filters from a reliability perspective, besides other considerations. An enhanced model is derived to quantify the lifetime of the capacitor in the filter considering the electro-thermal stress on it. Furthermore, the influence...

  4. The effect of semen collection method and level of egg yolk on capability of dilution and storage of buck semen

    Directory of Open Access Journals (Sweden)

    N.N. Dhaher

    2013-12-01

    Full Text Available The study was conducted to evaluate the effect of semen collection method for reduction of the deleterious interaction between the enzymes of bulbourethral gland and egg yolk during the dilution and storage of buck semen by three different level of egg yolk. Ten bucks were used in this study; the bucks were divided into two groups (five bucks in each group. Semen samples were collected once a week for four weeks from the bucks in first group using an artificial vagina, and from the animals in second group using an electroejaculator. The collected semen samples were diluted with sodium citrate extender with three different level of egg yolk (5, 10 and 20%. Extend semen samples were stored at 5 °C for three days. Computer assisted sperm analysis and Sperm Class Analyzer® were used for evaluation of the buck semen samples. Sperm motility parameters were evaluated which includes; percentage of motile sperm, percentage of progressive motile sperm, the value of the linear velocity (VSL, the value of the average velocity (VAP, the value of the curvilinear velocity (VCL, and the amplitude of lateral movement of the head (ALH. Results showed that all sperm motility parameters under the different level of egg yolk in semen samples that collected by artificial vagina were significantly higher than those which collected by electroejaculator. The percentage of motile sperm and progressive motile sperm of samples that collected by artificial vagina were higher at 10% of egg yolk, while these motility parameters were higher at 5% of egg yolk for semen samples that collected by electroejaculator. The differences between the two methods of semen collection in VCL and ALH were clear and the values were higher in samples that collected using the artificial vagina. The values of VSL, VAP and VCL of semen samples that collected by artificial vagina were higher at the second day than first day of semen storage under 10% of egg yolk. In conclusion, there are effects

  5. 78 FR 46948 - Proposed Agreement Regarding Site Costs and Covenants Not To Sue for American Lead and Zinc Mill...

    Science.gov (United States)

    2013-08-02

    ... AGENCY Proposed Agreement Regarding Site Costs and Covenants Not To Sue for American Lead and Zinc Mill... response costs incurred at the American Lead and Zinc Mill Superfund Site near Ouray, Colorado. The... via electric mail at rudy.mike@epa.gov and should reference the American Lead and Zinc Mill Site,...

  6. Tratamento da espondilólise sintomática com reparo direto pela técnica de Buck modificada Tratamiento de la espondilolisis sintomática con preparo directo por la técnica de Buck modificada Modified Buck's direct repair to simptomatic spondylolysis treatment

    OpenAIRE

    Bruno Pinto Coelho Fontes; Maurício Erwin Pühler Resende; Carlos Moreira Rezende; Rodrigo D'Alessandro de Macedo; Luis Olímpio Garcia Pedrosa; Jefferson Soares Leal; Rogério Lúcio Chaves de Resende

    2009-01-01

    OBJETIVO: justificar a reconstrução da pars interarticularis pela técnica modificada de Buck como método efetivo no tratamento de lombalgia por espondilólise ou espondilolistese tipo 1, refratárias ao tratamento conservador. MÉTODOS: avaliação retrospectiva de oito pacientes com idade entre 11 e 34 anos, operados e acompanhados no período de outubro de 2004 a maio de 2008 com a técnica de Buck utilizando-se parafusos canulados de titânio. Nenhum paciente foi imobilizado no pós-operatório. Os ...

  7. 77 FR 47840 - American Drum and Pallet Company Site; Memphis, Shelby County, Tennessee; Notice of settlement

    Science.gov (United States)

    2012-08-10

    ... AGENCY American Drum and Pallet Company Site; Memphis, Shelby County, Tennessee; Notice of settlement... Agency has entered into a settlement for past response costs concerning the American Drum and Pallet... Drum and Pallet Company Site by one of the following methods: www.epa.gov/region4/superfund/programs...

  8. SITE TECHNOLOGY CAPSULE: INPLANT SYSTEMS, INC. SFC 0.5 OLEOFILTRATION SYSTEM

    Science.gov (United States)

    Oleofiltration is used to separate suspended, emulsified and a portion of dissolved hydrocarbons from water. The InPlant Systems, Inc., SFC 0.5 Oleofiltration System was demonstrated under the SITE Program in June 1994 at a Superfund site in Florida that was contaminated with 29,...

  9. Analysis the application of quadratic Buck-Boost converter in photovoltaic energy-conversion system%二次型 Buck-Boost 变换器在光伏系统的应用分析

    Institute of Scientific and Technical Information of China (English)

    修瑞仙; 张士宇

    2015-01-01

    This paper introduced the working state of single switch quadratic Buck-Boost converter in continuous-discontinuous conduction mode, researched the photovoltaic cells model and maximum power tracking theory,through the simulation analysis,obtained the quadratic CDCM Buck-Boost converter applied to photovoltaic power generation system could realize the maximum power point tracking and wide range maximum power tracking,and was not affected by load change.%介绍了单开关二次型Buck-Boost变换器在连续—断续导电模式下的工作状态,研究了光伏电池模型及最大功率跟踪原理,通过仿真分析,得出将二次型CDCM Buck-Boost变换器应用到光伏发电系统中可实现最大功率点跟踪与宽范围的最大功率跟踪,并且不受负载变化影响。

  10. A current-mode DC-DC buck converter with adaptive zero compensation

    Institute of Scientific and Technical Information of China (English)

    Yang Ling; Dai Guoding; Xu Chongwei; Liu Yuezhi

    2013-01-01

    To achieve fast transient response for a DC-DC buck converter,an adaptive zero compensation circuit is presented.The compensation resistance is dynamically adjusted according to the different output load conditions,and achieves an adequate system phase margin under the different conditions.An improved capacitor multiplier circuit is adopted to realize the minimized compensation capacitance size.In addition,analysis of the small-signal model shows the correctness of the mechanism of the proposed adaptive zero compensation technique.A currentmode DC-DC buck converter with the proposed structure has been implemented in a 0.35 μm CMOS process,and the die size is only 800 × 1040 μm2.The experimental results show that the transient undershoot/overshoot voltage and the recovery times do not exceed 40 mV and 30 μs for a load current variation from 100 mA to 1 A.

  11. Performance Analysis of Trench Power MOSFETs in High-Frequency Synchronous Buck Converter Applications

    Directory of Open Access Journals (Sweden)

    Yali Xiong

    2008-01-01

    Full Text Available This paper investigates the performance perspectives and theoretical limitations of trench power MOSFETs in synchronous rectifier buck converters operating in the MHz frequency range. Several trench MOSFET technologies are studied using a mixed-mode device/circuit modeling approach. Individual power loss contributions from the control and synchronous MOSFETs, and their dependence on switching frequency between 500 kHz and 5 MHz are discussed in detail. It is observed that the conduction loss contribution decreases from 40% to 4% while the switching loss contribution increases from 60% to 96% as the switching frequency increases from 500 KHz to 5 MHz. Beyond 1 MHz frequency there is no obvious benefit to increase the die size of either SyncFET or CtrlFET. The RDS(ON×QG figure of merit (FOM still correlates well to the overall converter efficiency in the MHz frequency range. The efficiency of the hard switching buck topology is limited to 80% at 2 MHz and 65% at 5 MHz even with the most advanced trench MOSFET technologies.

  12. Study on Nonlinear Phenomena in Buck-Boost Converter with Switched-Inductor Structure

    Directory of Open Access Journals (Sweden)

    Hongchen Liu

    2013-01-01

    Full Text Available The switched-inductor structure can be inserted into a traditional Buck-Boost converter to get a high voltage conversion ratio. Nonlinear phenomena may occur in this new converter, which might well lead the system to be unstable. In this paper, a discrete iterated mapping model is established when the new Buck-Boost converter is working at continuous conduction current-controlled mode. On the basis of the discrete model, the bifurcation diagrams and Poincare sections are drawn and then used to analyze the effects of the circuit parameters on the performances. It can be seen clearly that various kinds of nonlinear phenomena are easy to occur in this new converter, including period-doubling bifurcation, border collision bifurcation, tangent bifurcation, and intermittent chaos. Value range of the circuit parameters that may cause bifurcations and chaos are also discussed. Finally, the time-domain waveforms, phase portraits, and power spectrum are obtained by using Matlab/Simulink, which validates the theoretical analysis results.

  13. 升降式交流斩波器%Buck-Boost AC/AC Direct Converter

    Institute of Scientific and Technical Information of China (English)

    孙刚; 洪峰

    2009-01-01

    介绍了一种新颖的Buck-Boost型交流斩波器.该交流斩波器将Buck-Boost型DC/DC变换器的开关管双向化,可实现单级降压或升压的AC/AC直接变换和能量双向流动.该变换器使用较少的功率器件实现了单级功率变换和能量双向流动,有利于提高变换器的功率密度和变换效率.详细研究了其工作模态和原理.分析了该变换器的两种PWM调制策略,并指出采用第2种调制策略可降低开关损耗.采用滞环电流控制的Buck/Boost型交流斩波器可对输入电压畸变进行有效抑制,保持了输出电压波形的高度正弦化.仿真和实验验证了分析的正确性.

  14. A New Transformerless Single-Phase Buck-Boost AC Voltage Regulator

    Directory of Open Access Journals (Sweden)

    YALCIN, F.

    2016-05-01

    Full Text Available Voltage regulation is one of the important goals for electrical sources and consumers. In this paper a new transformerless single-phase AC voltage regulator based on buck-boost converter topology is presented. The regulator circuit has a simple structure using only two bidirectional active switches, one inductor and one capacitor. A closed loop control system is implemented for the proposed regulator operation. A control law depending on the instantaneous values of the regulator's real input and desired output voltage is obtained and supports the PI controller. The control law allows the controller to obtain efficient pulse width modulation (PWM switching duty ratio for the desired output voltage when the input voltage has surges or fluctuations and the output load is changed. An experimental laboratory setup has been implemented for the proposed AC voltage regulator. The obtained results demonstrate that the proposed topology is capable of and efficient for both bucking and boosting the input AC voltage to a high quality output voltage with a low total harmonic distortion (THD for different input voltage and load conditions.

  15. High-accuracy current sensing circuit with current compensation technique for buck-boost converter

    Science.gov (United States)

    Rao, Yuan; Deng, Wan-Ling; Huang, Jun-Kai

    2015-03-01

    A novel on-chip current sensing circuit with current compensation technique suitable for buck-boost converter is presented in this article. The proposed technique can sense the full-range inductor current with high accuracy and high speed. It is mainly based on matched current mirror and does not require a large proportion of aspect ratio between the powerFET and the senseFET, thus it reduces the complexity of circuit design and the layout mismatch issue without decreasing the power efficiency. The circuit is fabricated with TSMC 0.25 µm 2P5M mixed-signal process. Simulation results show that the buck-boost converter can be operated at 200 kHz to 4 MHz switching frequency with an input voltage from 2.8 to 4.7 V. The output voltage is 3.6 V, and the maximum accuracy for both high and low side sensing current reaches 99% within the load current ranging from 200 to 600 mA.

  16. Integrated mixed signal control IC for 500-kHz switching frequency buck regulator

    Science.gov (United States)

    Chen, Keng; Zhang, Hong

    2015-12-01

    The main purpose for this work is to study the challenges of designing a digital buck regulator using pipelined analog to digital converter (ADC). Although pipelined ADC can achieve high sampling speed, it will introduce additional phase lag to the buck circuit. Along with the latency brought by processing time of additional digital circuits, as well as the time delay associated with the switching frequency, the closed loop will be unstable; moreover, raw ADC outputs have low signal-to-noise ratio, which usually need back-end calibration. In order to compensate these phase lag and make control loop unconditional stable, as well as boost up signal-to-noise ratio of the ADC block with cost-efficient design, a finite impulse response filter followed by digital proportional-integral-derivative blocks were designed. All these digital function blocks were optimised with processing speed. In the system simulation, it can be found that this controller achieved output regulation within 10% of nominal 5 V output voltage under 1 A/µs load transient condition; moreover, with the soft-start method, there is no turn-on overshooting. The die size of this controller is controlled within 3 mm2 by using 180 nm CMOS technology.

  17. Uranium occurrences in Bucks County, Pennsylvania, and Hunterdon County, New Jersey

    Science.gov (United States)

    McKeown, F.A.; Choquette, P.W.; Baker, R.C.

    1954-01-01

    Eleven occurrences of uraniferous argillite in the Lockatong lithofacies and five occurrences of uraniferous sandstone in the Stockton lithofacies, both of Triassic age, are known in Buck County, Pa. and Hunterdon County, N.J. Most of the occurrences were discovered by the Geological Survey, though prospectors found several. The Delaware quarry, Bucks County, Pa., was mapped and sampled in detail because the best exposed and most uraniferous argillite known crops out there. Sketches of two sandstone occurrences were made. Two stratigraphic sections of part of the Stockton formation were made in an unsuccessful effort to find key beds to which the uranium occurrences might be referred. The argillite occurrences contain as much as 0.034 percent uranium but commonly contain only about 0.010 percent uranium. They are known to extend for several hundred feet along the strike and may possibly extend several thousand feet, but less than a mile. They range from about 1 to 6 feet in thickness. The sandstone occurrences are characterized by the presence of pyrite or limonite and the alteration of feldspar to clay. The most uraniferous parts of the sandstone contain mud pebbles or lenses. The sandstone with mud pellets generally contain from 0.01 to 0.03 percent uranium, but selected parts of the pellets contain as much as 0.29 percent uranium. The known occurrences are small, about 1 to 2 feet thick and 20 to 30 feet long. None of the argillite or sandstone occurrences are now of economic importance.

  18. Cross-Regulation Assessment of DIDO Buck-Boost Converter for Renewable Energy Application

    Directory of Open Access Journals (Sweden)

    Deepak Elamalayil Soman

    2017-06-01

    Full Text Available When medium- or high-voltage power conversion is preferred for renewable energy sources, multilevel power converters have received much of the interest in this area as methods for enhancing the conversion efficiency and cost effectiveness. In such cases, multilevel, multi-input multi-output (MIMO configurations of DC-DC converters come to the scenario for integrating several sources together, especially considering the stringent regulatory needs and the requirement of multistage power conversion systems. Considering the above facts, a three-level dual input dual output (DIDO buck-boost converter, as the simplest form of MIMO converter, is proposed in this paper for DC-link voltage regulation. The capability of this converter for cross regulating the DC-link voltage is analyzed in detail to support a three-level neutral point clamped inverter-based grid connection in the future. The cross-regulation capability is examined under a new type of pulse delay control (PDC strategy and later compared with a three-level boost converter (TLBC. Compared to conventional boost converters, the high-voltage three-level buck boost converter (TLBBC with PDC exhibits a wide controllability range and cross regulation capability. These enhanced features are extremely important for better regulating variable output renewable energy sources such as solar, wind, wave, marine current, etc. The simulation and experimental results are provided to validate the claim.

  19. Dynamics and stabilization of peak current-mode controlled buck converter with constant current load

    Science.gov (United States)

    Leng, Min-Rui; Zhou, Guo-Hua; Zhang, Kai-Tun; Li, Zhen-Hua

    2015-10-01

    The discrete iterative map model of peak current-mode controlled buck converter with constant current load (CCL), containing the output voltage feedback and ramp compensation, is established in this paper. Based on this model the complex dynamics of this converter is investigated by analyzing bifurcation diagrams and the Lyapunov exponent spectrum. The effects of ramp compensation and output voltage feedback on the stability of the converter are investigated. Experimental results verify the simulation and theoretical analysis. The stability boundary and chaos boundary are obtained under the theoretical conditions of period-doubling bifurcation and border collision. It is found that there are four operation regions in the peak current-mode controlled buck converter with CCL due to period-doubling bifurcation and border-collision bifurcation. Research results indicate that ramp compensation can extend the stable operation range and transfer the operating mode, and output voltage feedback can eventually eliminate the coexisting fast-slow scale instability. Project supported by the National Natural Science Foundation of China (Grant No. 61371033), the Fok Ying-Tung Education Foundation for Young Teachers in the Higher Education Institutions of China (Grant No. 142027), the Sichuan Provincial Youth Science and Technology Fund, China (Grant Nos. 2014JQ0015 and 2013JQ0033), and the Fundamental Research Funds for the Central Universities, China (Grant No. SWJTU11CX029).

  20. A Simple Control Strategy Using Speedy Transient Response for Multiphase Buck Converter

    Science.gov (United States)

    Sasikala, K.; Ravikumar, D.; Rubini, B.

    2017-03-01

    The high performance of recent originating digital processors requires power supply for transient output, firm voltage regulation and high current. Industry has taken up interleaved multiphase synchronous buck converters for meeting such demands. Application of the voltage mode (ripple) hysteretic strategy to multiphase Voltage Regulator Units (VRU) would help satisfying many of the upcoming digital processors and IC’s powering demands. This arises from the use of the various advantages that can be obtained from this technique. This current division method is known for several benefits it provides: easy accessibility in application to all control methods, with freedom from the prime control technique in voltage regulation loop, absence of any necessity for current reference, better accuracy in current division of equal magnitude at almost every load conditions in standstill and transients. As against this, there are several challenges that involve distribution of multiple control signals, current sharing and sensitivity to noise, high speed comparators, hysteretic band accuracy and stable at large load transients. In addition, application of the current division technique presented was made to a multiphase voltage mode ripple controlled Buck Converter that produced a novel and easy control strategy having minimum output voltage ripples and speedy transient output.

  1. The Series Connected Buck Boost Regulator Concept for High Efficiency Light Weight DC Voltage Regulation

    Science.gov (United States)

    Birchenough, Arthur G.

    2003-01-01

    Improvements in the efficiency and size of DC-DC converters have resulted from advances in components, primarily semiconductors, and improved topologies. One topology, which has shown very high potential in limited applications, is the Series Connected Boost Unit (SCBU), wherein a small DC-DC converter output is connected in series with the input bus to provide an output voltage equal to or greater than the input voltage. Since the DC-DC converter switches only a fraction of the power throughput, the overall system efficiency is very high. But this technique is limited to applications where the output is always greater than the input. The Series Connected Buck Boost Regulator (SCBBR) concept extends partial power processing technique used in the SCBU to operation when the desired output voltage is higher or lower than the input voltage, and the implementation described can even operate as a conventional buck converter to operate at very low output to input voltage ratios. This paper describes the operation and performance of an SCBBR configured as a bus voltage regulator providing 50 percent voltage regulation range, bus switching, and overload limiting, operating above 98 percent efficiency. The technique does not provide input-output isolation.

  2. A Ripple Suppression with Staggered Parallel Buck/Boost Converter Light Load Efficiency Research%一种带纹波抑制的交错并联Buck/Boost变换器轻载效率研究

    Institute of Scientific and Technical Information of China (English)

    刘悦新; 王磊

    2016-01-01

    非隔离型交错并联双向Buck/Boost变换器普遍存在轻载效率低的难题。以多相交错并联Buck/Boost变换器Boost模式为研究对象,分别对其工作在DCM和CCM模式下的功率损耗进行综合性分析研究。根据变换器轻载运行时降低频率可以提高效率的原则,提出最优化调频原则,对其不同负载下开关频率进行调整,以达到提高效率的目的。针对降低频率会带来纹波恶化的缺陷,将磁集成技术应用到交错并联双向Buck/Boost变换器,有效改善通道电感电流纹波及输出电压纹波,并给出磁集成后滤波电容优化设计原则,以最大程度减小损耗,提高轻载效率。最后通过仿真和实验验证了理论分析的正确性,为交错并联双向Buck/Boost 变换器轻载效率优化提供了新的理论依据,推动了全负载高效率双向Buck/Boost变换器的设计实现。%The non-isolated interleaving bi-directional Buck-Boost converter is faced with a widespread problem of low underloading efficiency. The Boost model of the multi-phase interleaving Buck/Boost converter is adopted as the research object in this paper, and a comprehensive analysis of power loss is conducted under the DCM and CCM model. According to the principle that efficiency can be increased through reduced frequency during underloading operation of the transformer, and the principle of optimized frequency modulation is put forward to adjust the switching frequency under different loads so as to realize the goal of increasing efficiency. Concerning the defect of worsening ripples caused by reduced frequency, the magnetic integration technique is applied to the interleaving bi-directional Buck/Boost converter to efficiently improve the channel’s inductive current ripples and the output voltage ripples. Besides, the filter capacitor optimized design principle after magnetic integration is given at an attempt to minimize loss and increase underloading

  3. Sustainable exposure prevention through innovative detection and remediation technologies from the NIEHS Superfund Research Program.

    Science.gov (United States)

    Henry, Heather F; Suk, William A

    2017-03-01

    Innovative devices and tools for exposure assessment and remediation play an integral role in preventing exposure to hazardous substances. New solutions for detecting and remediating organic, inorganic, and mixtures of contaminants can improve public health as a means of primary prevention. Using a public health prevention model, detection and remediation technologies contribute to primary prevention as tools to identify areas of high risk (e.g. contamination hotspots), to recognize hazards (bioassay tests), and to prevent exposure through contaminant cleanups. Primary prevention success is ultimately governed by the widespread acceptance of the prevention tool. And, in like fashion, detection and remediation technologies must convey technical and sustainability advantages to be adopted for use. Hence, sustainability - economic, environmental, and societal - drives innovation in detection and remediation technology. The National Institute of Health (NIH) National Institute of Environmental Health Sciences (NIEHS) Superfund Research Program (SRP) is mandated to advance innovative detection, remediation, and toxicity screening technology development through grants to universities and small businesses. SRP recognizes the importance of fast, accurate, robust, and advanced detection technologies that allow for portable real-time, on-site characterization, monitoring, and assessment of contaminant concentration and/or toxicity. Advances in non-targeted screening, biological-based assays, passive sampling devices (PSDs), sophisticated modeling approaches, and precision-based analytical tools are making it easier to quickly identify hazardous "hotspots" and, therefore, prevent exposures. Innovation in sustainable remediation uses a variety of approaches: in situ remediation; harnessing the natural catalytic properties of biological processes (such as bioremediation and phytotechnologies); and application of novel materials science (such as nanotechnology, advanced

  4. 基于Buck-Boost矩阵变换器的异步电机调速控制策略%A Buck-Boost matrix converter based strategy for control of the rotating speed of asynchronous motors

    Institute of Scientific and Technical Information of China (English)

    张小平; 尹翔; 刘士亚

    2014-01-01

    进行了将采用双闭环控制的Buck-Boost矩阵变换器用于异步电机调速系统控制的研究,设计了基于Buck-Boost矩阵变换器的异步电机调速控制策略.该策略根据异步电机的给定转速,基于矢量控制原理获得异步电机对应的输入电压,并以该电压作为Buck-Boost矩阵变换器的参考输出电压,再通过对Buck-Boost矩阵变换器采用双闭环控制策略使其实际输出电压与其参考输出电压保持一致,从而实现异步电机的实际转速对给定转速的准确跟踪,达到准确控制异步电机转速的目的.该控制策略的控制效果通过仿真得到了验证.仿真分析结果表明,异步电机采用基于Buck-Boost矩阵变换器的调速控制策略可取得良好的动态和稳态性能以及四象限运行特性,因而具有较好的应用价值.

  5. Current control of 6-phases 100kW interleaved buck/boost converter for railway application

    OpenAIRE

    2009-01-01

    The purpose of this paper is to present a 6-phases interleaved buck-boost converter of 100kW de-signed for a hybrid locomotive. The IGBT’s are working partially in continuous and discontinuous con-duction mode. Experiments show the effectiveness of the digital current control, current sharing and discontinuous-continuous transition with only one current sensor

  6. Estimation of Bidirectional Buck/boost DC/DC Converters with Electric Double-Layer Capacitors for Energy Storage Systems

    Science.gov (United States)

    Funabiki, Shigeyuki; Yamamoto, Masayoshi

    Renewable energy such as wind force and solar light has collected the attention as alternative energy sources of fossil fuel. An energy storage system with an electric double-layer capacitor (EDLC), which balances the demand and supply power, is required in order to introduce the electric power generating system that utilizes renewable energy. Currently, the research and development of these energy storage systems are actively carried out. In the energy storage system with an EDLC, the DC/DC converter having the function of the bidirectional power flow and the buck/boost performance is essential as an interface and power control circuit. There are two types of the bidirectional buck/boost DC/DC converters. One type consists of two buck/boost DC/DC converters with one reactor. The other type consists of two sets of two-quadrant DC/DC converters with one reactor. This paper discusses the comparison of these types of DC/DC converters with bidirectional power flow and buck/boost performance. The two types of DC/DC converters are estimated for their application to the energy storage system with the EDLC. As the voltage endurance of the device is lower and the mean current is smaller in the latter type of converter despite of having twice the number of devices compared to the former, the latter type of converter has the advantage of a smaller reactor, i.e., core volume and loss, and lower loss in the converter.

  7. Semen characteristics and sexual hormones of Hy-Plus rabbit bucks influenced by a dietary multi-enzymes additive

    Directory of Open Access Journals (Sweden)

    H. Gado

    2015-06-01

    Full Text Available A total of 144 adult Hy-Plus rabbit bucks were randomly assigned into  four treatments of 36 replicates each, in a completely randomized design. Animals were fed ad libitum on basal diet supplemented with an enzyme complex (EZ at 0 (EZ0, 1 (EZ1, 3 (EZ3 and 5 (EZ5 kg/ton of feed. Total sperm count was higher (P<0.05 in EZ5 than in EZ0. Sperm motility increased with increasing levels of the EZ additive being lowest for EZ0 and highest for EZ5 rabbits (P<0.05. Percentage of dead sperm was higher (P<0.05 in EZ0 than in EZ5 rabbits. Rabbit bucks received the highest levele of EZ in their diet, had the shorter reaction time (22.31±3.17 sec; P<0.05,whereas EZ5 bucks took 43.56±5.89 sec to mount does for the first time after exposure. Blood testosterone, 17α-estradiol and progesterone levels were highest in EZ5 rabbits and lowest in EZ0 rabbits. Enzyme addition increased (P<0.05 sperm transit in estrus doe cervical mucus. Data suggested that the EZ additive in diets of  adult Hy-Plus rabbit bucks was effective to improve both semen characteristics and sexual drive.

  8. Monolithic quasi-sliding-mode controller for SIDO buck converter with a self-adaptive free-wheeling current level

    Institute of Scientific and Technical Information of China (English)

    Wu Xiaobo; Liu Qing; Zhao Menglian; Chen Mingyang

    2013-01-01

    An analog implementation of a novel fixed-frequency quasi-sliding-mode controller for single-inductor dual-output (SIDO) buck converter in pseudo-continuous conduction mode (PCCM) with a self-adaptive freewheeling current level (SFCL) is presented.Both small and large signal variations around the operation point are considered to achieve better transient response so as to reduce the cross-regulation of this SIDO buck converter.Moreover,an internal integral loop is added to suppress the steady-state regulation error introduced by conventional PWM-based sliding mode controllers.Instead of keeping it as a constant value,the free-wheeling current level varies according to the load condition to maintain high power efficiency and less cross-regulation at the same time.To verify the feasibility of the proposed controller,an SIDO buck converter with two regulated output voltages,1.8 V and 3.3 V,is designed and fabricated in HEJIAN 0.35 μm CMOS process.Simulation and experiment results show that the transient time of this SIDO buck converter drops to 10 μs while the cross-regulation is reduced to 0.057 mV/mA,when its first load changes from 50 to 100 mA.

  9. Power Flow Control of a Dual-Input Interleaved Buck/Boost Converter with Galvanic Isolation for Renewable Energy Systems

    DEFF Research Database (Denmark)

    Mira Albert, Maria del Carmen; Zhang, Zhe; Knott, Arnold

    2015-01-01

    DC microgrids or nanogrids have attracted increasing research interest in recent years. Therefore, as a critical component, dc-dc converters with multiple inputs are required. In this paper, a dual-input interleaved buck/boost converter is proposed and its corresponding power flow control methods...

  10. Almost Redundant Components in the 3 alpha Faddeev Equation for the Buck, Friedlich and Wheatly alpha alpha Potential

    CERN Document Server

    Fujiwara, Y; Kohno, M

    2004-01-01

    The 3 alpha orthogonality condition model using the Pauli-forbidden bound states of the Buck, Friedlich and Wheatly alpha alpha potential can yield a compact 3 alpha ground state with a large binding energy, in which a small admixture of the redundant components can never be eliminated.

  11. Design of isolated Buck-Boost DC/DC converter%Buck-Boost隔离直流转换器设计

    Institute of Scientific and Technical Information of China (English)

    王雪丹; 李文鹤

    2012-01-01

    Buck-Boost隔离直流转换器宽范围输入电压的条件下,分析了典型的全桥Boost转换器拓扑结构,由于存在的谐振电感包括漏电感,全桥Boost转换器只能采用双边沿调制.该转换器采用UC3895作为控制器,对全桥单元采用移相转换控制的方式,为了提高全桥Boost转换器系统的可靠性和效率,采用三模式两频率控制方式,在输入宽范围电压的情况下,最高500 V输入,360 V输出.在此采用Matlab软件进行仿真,实验结果表明输入电压平均效率范围是96.2%,最高效率能达到97.5%.%The topology structure of a typical FB Boost converter was analyzed under the condition of wide range input voltage of isolated Buck-Boost DC/DC converter. The FB Boost converter can only adopt two-edge-modulation (TEM) due to the resonant induction including the leakage induction. The converter takes UC3895 available in market as the controller to control the FB-cell with phase-shifted. In order to improve the reliability and efficiency of the FB-Boost converter, a three-mode dual-frequency control mode was used. The maximum input voltage is 500 V and the output'is 360 V in the case of the wide range input voltage. The Matlab software was adopted for simulation. The result shows the the average efficiency range of the input-voltage is 96. 2% and the highest efficiency can reach to 97. 3%.

  12. Semen quality and concentration of soluble proteins in the seminal plasma of Alpine bucks Semen quality and concentration of soluble proteins in the seminal plasma of Alpine bucks

    Directory of Open Access Journals (Sweden)

    Simone Eliza Facione Guimarães

    2010-06-01

    Full Text Available It was aimed to study the in vitro seminal quality analyzed by complementary tests and to compare them with physical, morphological and biochemical aspects of male goat semen of the Alpine breed. This experiment took place at the Federal University of Viçosa, situated at 20º45’ S latitude and 42º51’ W longitude, Southwest of Brazil. It was done during the summer months of January and February, and three adult male goats of the Alpine breed were used in intensive conditions. The semen was collected by artificial vagina method. In all semen samples (45 ejaculates, after the physical and morphological analysis, the hiposmotic test was done. In 24 ejaculates, it were done thermo-resistance test, and in 21 ejaculates it were determined the concentration of total soluble proteins in seminal plasma. The male goats presented difference in the semen physical and morphological aspects, in the hiposmotic test and thermo-resistance test, but they did not presented difference in total soluble proteins concentration in seminal plasma. Results of the slow thermo-resistance test and hiposmotic test were positively correlated (r = 0.60. It was concluded, according to our results, that the concentration of total soluble proteins in seminal plasma can not be used as a parameter to predict the seminal quality of Alpine bucks.It was aimed to study the in vitro seminal quality analyzed by complementary tests and to compare them with physical, morphological and biochemical aspects of male goat semen of the Alpine breed. This experiment took place at the Federal University of Viçosa, situated at 20º45’ S latitude and 42º51’ W longitude, Southwest of Brazil. It was done during the summer months of January and February, and three adult male goats of the Alpine breed were used in intensive conditions. The semen was collected by artificial vagina method. In all semen samples (45 ejaculates, after the physical and morphological analysis, the hiposmotic test

  13. Optimization of Inductance for Buck DC-DC Converter%Buck DC-DC变换器电感的优化设计

    Institute of Scientific and Technical Information of China (English)

    付园园; 姚素英; 徐江涛; 高静; 陈莞

    2012-01-01

    提出了一种优化电感的设计方法,以最小的电感实现了Buck DC-DC变换器最大输出纹波电压(MOVR)达到极小值.该方法首先通过计算得到连续导电模式(CCM)和不连续导电模式(DCM)下的输出纹波电压,然后根据电感取值分析这两种模式下的MOVR,最终得到了使MOVR达到极小值的最小电感.分析得到,对于任意给定的输入电压和负载范围,计算最大输入电压、最小负载下CCM和DCM模式的临界电感和最小输入电压、最大负载下的临界电感,则最优电感为两者中的较大值.Pspice仿真结果验证了上述理论分析的正确性,开关频率为52 kHz,输出电压12 V时,对于给定输入电压范围15~21V,负载范围35~170 Ω,最优电感为327μH.%In order to realize the lowest maximum output voltage ripple (MOVR) of Buck DC-DC converter with the minimal inductance, an optimal inductance design method is proposed. Output voltage, ripple (OVR) under continuous conduction mode (CCM) and discontinuous mode (DCM) was obtained by calculation, then MOVR in the two modes was analyzed according to the inductance value, and ultimately the minimum inductance to achieve the lowest MOVR was obtained. For any given range of the load and input voltage, by comparing the critical inductance between CCM and DCM under the maximum input voltage, minimum load condition and under the minimum input voltage, maximum load condition, it is concluded that the minimum inductance to guarantee the lowest MOVR is actually the maximum value of the critical inductance under the two conditions. The Pspice simulation results are in favor of the proposed theory.

  14. 浅议 PTA 料仓装车系统的设计%The Design of PTA Buck Silo & Truck Loading

    Institute of Scientific and Technical Information of China (English)

    彭荣杰

    2013-01-01

    The paper mainly introduced the design of PTA buck silo & truck loading .In order to better grasp the technology of PTA buck silo & truck loading, The principle of PTA buck silo & truck loading was analyzed and discussed.%  文章主要介绍了 PTA 料仓装车系统的的设计。通过对装车系统设计的一些设计原则进行了分析和探讨,以便于更好地掌握和改进PTA 料仓装车系统的技术。

  15. Design of isolated Buck-Boost DC/DC converter%Buck-Boost隔离直流转换器设计

    Institute of Scientific and Technical Information of China (English)

    王雪丹; 李文鹤

    2013-01-01

    Buck-Boost隔离直流转换器宽范围输入电压的条件下,分析了典型的全桥boost转换器拓扑结构,由于存在的谐振电感包括漏电感,全桥Boost转换器只能采用双边沿调制[1],该转换器采用UC3895作为控制器,对全桥单元采用移相转换控制的方式,为了提高全桥boost转换器系统的可靠性和效率,采用三模式两频率控制方式[2],在输入宽范围电压的情况下,最高输入500V,输出360V,采用Matlab软件进行仿真,实验结果表明输入电压平均效率范围是96.2%,最高效率能达到97.5%.

  16. SUPERFUND TREATABILITY CLEARINGHOUSE: CERCLA BDAT SARM PREPARATION AND RESULTS OF PHYSICAL SOILS WASHING EXPERIMENTS (FINAL REPORT)

    Science.gov (United States)

    This study reports on the results of work preparing 30,000 Ibs of SARM or synthetic analytical reference matrix, a surrogate Superfund soil containing a vide range of contaminants. It also reports the results ©f bench scale treatability experiments designed to simulate the EP...

  17. Simulation of Multi output Fly back Converter with Integrated Auxiliary Buck Converter with reduced components

    Directory of Open Access Journals (Sweden)

    J.KOMATHI

    2015-04-01

    Full Text Available The fly back converter has been widely used for multi outputs due to the simple structure and low cost in low-power applications. This paper presents a new multi output converter. It consists of a half-bridge inverter with boost converter in primary side and a fly back rectifier that is integrated with an auxiliary buck converter in secondary side. The boost converter is used to generate high voltage dc from Low voltage PV cells. The primary switches control the main output voltage and the secondary synchronous switches control the auxiliary output voltage. The main advantages of the proposed converter are that the transformer size can be reduced due to the less magnetizing offset current, all the power switches including synchronous ones can achieve the zero-voltage switching (ZVS and it has no output cross regulation problems. The circuit is simulated using MATLAB. The performance is verified with simulation results.

  18. Stability Analysis of the Buck-Boost Type Solar Array Regulator

    Science.gov (United States)

    Yang, Jeong-Hwan; Yoon, Seok-Teak; Park, Hee-Sung; Park, Sung-Woo; Koo, Ja-Chun; Jang, Jin-Baek; Lee, Sang-Kon

    2014-08-01

    The SAR (Solar Array Regulator) is different from a general DC-DC Converter. The input of the SAR is connected to the solar array and the output is connected to the battery. So, the output voltage of the SAR is constant and the input voltage of the SAR is variable. And the solar array current which is the SAR input current is variable according to the solar array voltage. Therefore, the SAR is influenced by the electrical characteristic of the solar array. For these reasons, a small signal model for a general DC-DC converter cannot be applied to the SAR for the stability analysis. In this paper, the small signal model of the BUCK-BOOST type SAR (BBSAR) is introduced and its transfer functions are induced. Using small signal transfer functions, the stability analysis is performed and its results are compared to the simulation result.

  19. Advanced Energy Conversion System Using Sinusoidal Voltage Tracking Buck-Boost Converter Cascaded Polarity Changing Inverter

    Science.gov (United States)

    Ahmed, Nabil A.

    2011-06-01

    This paper presents an advanced power converter employs a sinusoidal voltage absolute value tracking buck-boost DC-DC converter in the first power processing stage and a polarity changing full-bridge inverter in the second stage. The proposed power conversion system has the capability of delivering sinusoidal output and input current with unity power factor and good output voltage regulation. Consequently, the complete voltage regulator system, which is mainly suitable for new energy generation systems as well as energy storage systems, can be constructed compactly and inexpensively without DC link electrolytic capacitor. Also, the paper presents an auxiliary passive resonant circuit for soft switching operation. Simulation results using PSIM software are presented to verify the operation principles and feasibility of the proposed power conversion system.

  20. Closed-loop analysis and control of a non-inverting buck-boost converter

    Science.gov (United States)

    Chen, Zengshi; Hu, Jiangang; Gao, Wenzhong

    2010-11-01

    In this article, a cascade controller is designed and analysed for a non-inverting buck-boost converter. The fast inner current loop uses sliding mode control. The slow outer voltage loop uses the proportional-integral (PI) control. Stability analysis and selection of PI gains are based on the nonlinear closed-loop error dynamics incorporating both the inner and outer loop controllers. The closed-loop system is proven to have a nonminimum phase structure. The voltage transient due to step changes of input voltage or resistance is predictable. The operating range of the reference voltage is discussed. The controller is validated by a simulation circuit. The simulation results show that the reference output voltage is well-tracked under system uncertainties or disturbances, confirming the validity of the proposed controller.

  1. Análisis de la estabilidad de un convertidor buck multicelular de dos celdas

    Directory of Open Access Journals (Sweden)

    Julián Pelaéz

    2014-12-01

    Full Text Available En este trabajo se presenta un convertidor multicelular con dos células bajo un modo de modulación (PWM de control de voltaje por ancho de pulso. El convertidor buck multicelular obtenido puede ser utilizado como un circuito electrónico de potencia para aplicaciones de alta tensión; donde los dispositivos semiconductores tienen la capacidad de cambiar solo a niveles de bajo voltaje. El análisis de estabilidad se ha hecho para un control puramente proporcional y más tarde, se ha extendido para un control Proporcional-Integral (PI. Los resultados de la simulación demuestran la validez del análisis.

  2. H∞ LPV Control with Pole Placement Constraints for Synchronous Buck Converters with Piecewise-Constant Loads

    Directory of Open Access Journals (Sweden)

    Hwanyub Joo

    2015-01-01

    Full Text Available This paper addresses the output regulation problem of synchronous buck converters with piecewise-constant load fluctuations via linear parameter varying (LPV control scheme. To this end, an output-error state-space model is first derived in the form of LPV systems so that it can involve a mismatch error that temporally arises from the process of generating a feedforward control. Then, to attenuate the mismatch error in parallel with improving the transient behavior of the converter, this paper proposes an LMI-based stabilization condition capable of achieving both H∞ and pole-placement objectives. Finally, the simulation and experimental results are provided to show the validity of our approach.

  3. DC-DC buck converters for the CMS Tracker upgrade at SLHC

    Energy Technology Data Exchange (ETDEWEB)

    Feld, L; Jussen, R; Karpinski, W; Klein, K; Sammet, J, E-mail: Katja.Klein@cern.ch [1. Physikalisches Institut B, RWTH Aachen University, Sommerfeldstrasse 14, 52074 Aachen (Germany)

    2011-01-15

    The CMS experiment at the Large Hadron Collider (LHC) at CERN, Geneva, is planning major upgrades of its current pixel and strip detectors for the LHC luminosity upgrade, known as the SLHC. Due to the larger channel count and - in case of the strip tracker - increased functionality, the powering scheme adopted today, namely parallel powering of several detector modules, has to be abandoned. Instead, a powering scheme based on the DC-DC conversion technique is foreseen, which would lead to lower power losses in the supply cables, and would allow to reduce the material budget of cables and associated electronic boards in the sensitive detector volume. This paper deals with the development, characterisation and optimisation of DC-DC buck converter prototypes for the upgrades of the CMS pixel and strip detectors at the SLHC.

  4. A current-mode buck DC-DC controller with adaptive on-time control

    Energy Technology Data Exchange (ETDEWEB)

    Li Yanming; Lai Xinquan; Ye Qiang; Yuan Bing; Chen Fuji [Institute of Electronic CAD, Xidian University, Xi' an 710071 (China); Jia Xinzhang, E-mail: ymli2004@126.co, E-mail: xqlai@mail.xidian.edu.c [Microelectronics Institute, Xidian University, Xi' an 710071 (China)

    2009-02-15

    A current-mode buck DC-DC controller based on adaptive on-time (AOT) control is presented. The on-time is obtained by the techniques of input feedforward and output feedback, and the adaptive control is achieved by a sample-hold and time-ahead circuit. The AOT current-mode control scheme not only obtains excellent transient response speed, but also achieves the independence of loop stability on output capacitor ESR. In addition, the AOT current-mode control does not have subharmonic oscillation phenomenon seen in fixed frequency peak current-mode control, so there is no need of the slope compensation circuit. The auto-skip pulse frequency modulation (PFM) mode improves the conversion efficiency of light load effectively. The controller has been fabricated with UMC 0.6-mum BCD process successfully and the detailed experimental results are shown.

  5. A low noise high efficiency buck DC-DC converter with sigma-delta modulation

    Energy Technology Data Exchange (ETDEWEB)

    Cai Shujiang; Pi Changming; Yan Wei; Li Wenhong, E-mail: wenhongli@fudan.edu.cn [State Key Laboratory of ASIC and Systems, Fudan University, Shanghai 201203 (China)

    2011-07-15

    Some research efforts to improve the efficiency and noise performance of buck DC-DC converters are explored. A carefully designed power MOSFET driver, including a dead time controller, discontinuous current mode (DCM) controller and gate width controller, is proposed to improve efficiency. Instead of PWM modulation, sigma-delta modulation is introduced into the feedback loop of the converter to move out the clock-referred harmonic spike. The proposed converter has been designed and fabricated by a 0.35 {mu}m CMOS process. Measured results show that the peak efficiency of the converter can reach 93% and sigma-delta modulation suppresses the harmonic spike by 30 dB over PWM modulation. (semiconductor integrated circuits)

  6. Sliding mode controller with modified sliding function for DC-DC Buck Converter.

    Science.gov (United States)

    Naik, B B; Mehta, A J

    2017-09-01

    This article presents design of Sliding Mode Controller with proportional integral type sliding function for DC-DC Buck Converter for the controlled power supply. The converter with conventional sliding mode controller results in a steady state error in load voltage. The proposed modified sliding function improves the steady state and dynamic performance of the Convertor and facilitates better choices of controller tuning parameters. The conditions for existence of sliding modes for proposed control scheme are derived. The stability of the closed loop system with proposed sliding mode control is proved and improvement in steady state performance is exemplified. The idea of adaptive tuning for the proposed controller to compensate load variations is outlined. The comparative study of conventional and proposed control strategy is presented. The efficacy of the proposed strategy is endowed by the simulation and experimental results. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  7. Low-temperature operation of a Buck DC/DC converter

    Science.gov (United States)

    Ray, Biswajit; Gerber, Scott S.; Patterson, Richard L.; Myers, Ira T.

    1995-01-01

    Low-temperature (77 K) operation of a 42/28 V, 175 W, 50 kHz PWM Buck DC/DC converter designed with commercially available components is reported. Overall, the converter losses decreased at 77 K compared to room temperature operation. A full-load efficiency of 97 percent was recorded at liquid-nitrogen temperature, compared to 95.8 percent at room temperature. Power MOSFET operation improved significantly where as the output rectifier operation deteriorated at low-temperature. The performance of the output filter inductor and capacitor did not change significantly at 77 K compared to room temperature performance. It is possible to achieve high-density and high efficiency power conversion at low-temperatures due to improved electronic, electrical and thermal properties of materials.

  8. Quantization Effects on Period Doubling Route to Chaos in a ZAD-Controlled Buck Converter

    Directory of Open Access Journals (Sweden)

    John Alexander Taborda

    2012-01-01

    cycles. On the other hand many studies have been devoted to analyze the ZAD-controlled buck power converter, but these past studies did not include hardware considerations. In this paper, analog-to-digital conversion process is explicitly introduced in the modeling stage. As the feedback gain is varied, the dynamic behavior depending on the analog-to-digital converter resolution is numerically analyzed. Particularly, it is observed that including the quantizer in the model carries out several changes in the transitions to chaos, which include interruption of band-merging process by cascades of periodic inclusions, disappearing of band transitions, and multiple coexisting of periodic orbits. Many of these phenomena have not been reported as a consequence of the quantization effects.

  9. Comparative Performance Analysis of Sliding Mode and Q-Controller Algorithms for Buck Converter

    Science.gov (United States)

    Pati, Nivedita

    2017-08-01

    The switched mode dc-dc converters are some of the simplest power electronic circuits which have received an increasing deal of interest in many areas due to their high efficiency and small size. These converters are non-linear and time-variant in nature; hence the analysis, control and stabilization are the main factors that need to be considered. Many control methodology are used for control of switch mode dc-dc converters but the optimum one is always in demand. This paper presents the linearization of the Buck converter model and a comparison between a linear and non-linear control algorithms for better output voltage regulation along with robustness to change in input voltage and load parameters. The computer –aided design software tool Matlab/Simulink is used for the simulations and the results are presented.

  10. Optimal Control with Complete Load-Decoupled Design for the Buck DC-DC Switching Converter

    Institute of Scientific and Technical Information of China (English)

    Fei-Hu; Hsieh; Yau-Tarng; Juang

    2002-01-01

    This paper describes a new controller design procedure and turning method for the buck PWM DCDCswitching converter taking into consideration the equivalent series resistance of components. First, the linearoptimal feedback is designed by the LQR approach. Then the designed control law is implemented by aphase-lag lead controller incorporated with a complete load-decoupled PD compensator. The phase-lag lead controlleris tuned to achieve the optimal design based on the output error voltage directly, instead of using an estimator.With the proposed PD compensator, the converter is robust with respect to the load changes and parameterperturbations. We also provide the conditions for the robust stability assurance of the closed-loop system.

  11. Effect of Air Space in Storage Vials on Motility of Spermatozoa in Chilled Buck Semen

    Directory of Open Access Journals (Sweden)

    Magnus Paul K and Lali F Anand 1

    Full Text Available This study was conducted in order to find out the effect of air space on the top of glass vial in which semen is stored, on the motility of spermatozoa. 45 samples collected from two bucks over a span of 6 months were used for experiment. Goat milk extender was the diluent used. Two ml each of diluted semen after noting their initial motility was stored in 2 ml and 5 ml vials. Samples were stored at 5°C and motility of spermatozoa noted at 24 and 48 hours. Semen without air space was found to preserve the motility better than semen with air space on 24 and 48 hours of incubation. This could be better attributed to reactive oxygen species production by the spermatozoa, but further investigation is needed in this aspect to confirm it. [Veterinary World 2010; 3(9.000: 421-423

  12. A 10 MHz ripple-based on-time controlled buck converter with dual ripple compensation

    Institute of Scientific and Technical Information of China (English)

    Lü Danzhu; Yu Jiale; Hong Zhiliang

    2013-01-01

    A 10 MHz ripple-based on-time controlled buck converter is presented.A novel low-cost dual ripple compensation,which consists of coupling capacitor compensation and passive equivalent series resistance compensation,is proposed to achieve a fast load transient response and robust stability simultaneously.Implemented in a 2P4M 0.35 μm CMOS process,the converter achieves fix-frequency output with a ripple of below 10 mV and an overshoot of 10 mV at 400 mA step load transient response.With width optimization of the power transistors in an ultra-heavy load and PFM control in a light load,the efficiency stays at over 83% for a load range from 20 mA to 1.5 A and the peak efficiency reaches 90.16%.

  13. Design of high efficiency dual-mode buck DC-DC converter

    Science.gov (United States)

    Xinquan, Lai; Huali, Zeng; Qiang, Ye; Huisen, He; Shasha, Zhang; Yuqing, Sun

    2010-11-01

    A buck DC—DC switching regulator with high efficiency is implemented by automatically altering the modulation mode according to load current, and it can operate with an input range of 4.5 to 30 V. At light load current, the converter operates in skip mode. The converter enters PWM mode operation with increasing load current. It reduces the switching loss at light load and standby state, which results in prolonging battery lifetime and stand-by time. Meanwhile, externally adjustable soft-start minimizes the inrush supply current and avoids the overshoot of output voltage at initial startup. The regulator is fabricated by a 0.6 μm CDMOS process. The test results show that, under the condition of 3.3 V output, the efficiency is up to 64% at 5 mA and the maximum efficiency is 95.5%.

  14. Design of high efficiency dual-mode buck DC-DC converter

    Energy Technology Data Exchange (ETDEWEB)

    Lai Xinquan; Zeng Huali; Ye Qiang; He Huisen; Zhang Shasha; Sun Yuqing, E-mail: zenghuali4213@126.com, E-mail: xqlai@mail.xidian.edu.cn [Institute of Electronic CAD, Xidian University, Xi' an 710071 (China)

    2010-11-15

    A buck DC-DC switching regulator with high efficiency is implemented by automatically altering the modulation mode according to load current, and it can operate with an input range of 4.5 to 30 V. At light load current, the converter operates in skip mode. The converter enters PWM mode operation with increasing load current. It reduces the switching loss at light load and standby state, which results in prolonging battery lifetime and stand-by time. Meanwhile, externally adjustable soft-start minimizes the inrush supply current and avoids the overshoot of output voltage at initial startup. The regulator is fabricated by a 0.6 {mu}m CDMOS process. The test results show that, under the condition of 3.3 V output, the efficiency is up to 64% at 5 mA and the maximum efficiency is 95.5%.

  15. GENERAL: Mode shift and stability control of a current mode controlled buck-boost converter operating in discontinuous conduction mode with ramp compensation

    Science.gov (United States)

    Bao, Bo-Cheng; Xu, Jian-Ping; Liu, Zhong

    2009-11-01

    By establishing the discrete iterative mapping model of a current mode controlled buck-boost converter, this paper studies the mechanism of mode shift and stability control of the buck-boost converter operating in discontinuous conduction mode with a ramp compensation current. With the bifurcation diagram, Lyapunov exponent spectrum, time-domain waveform and parameter space map, the performance of the buck-boost converter circuit utilizing a compensating ramp current has been analysed. The obtained results indicate that the system trajectory is weakly chaotic and strongly intermittent under discontinuous conduction mode. By using ramp compensation, the buck-boost converter can shift from discontinuous conduction mode to continuous conduction mode, and effectively operates in the stable period-one region.

  16. Mode shift and stability control of a current mode controlled buck-boost converter operating in discontinuous conduction mode with ramp compensation

    Institute of Scientific and Technical Information of China (English)

    Bao Bo-Cheng; Xu Jian-Ping; Liu Zhong

    2009-01-01

    By establishing the discrete iterative mapping model of a current mode controlled buck-boost converter, this paper studies the mechanism of mode shift and stability control of the buck-boost converter operating in discontinuous conduction mode with a ramp compensation current. With the bifurcation diagram, Lyapunov exponent spectrum, timedomain waveform and parameter space map, the performance of the buck-boost converter circuit utilizing a compensating ramp current has been analysed. The obtained results indicate that the system trajectory is weakly chaotic and strongly intermittent under discontinuous conduction mode. By using ramp compensation, the buck-boost converter can shift from discontinuous conduction mode to continuous conduction mode, and effectively operates in the stable period-one region.

  17. NOAA ESRI Geotiff- 1m Multibeam Bathymetry of St. Croix (Buck Island), US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83 (NCEI Accession 0131860)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains an ESRI Geotiff with 1 meter cell size representing the bathymetry of the north shore of St. Croix (Buck Island), US Virgin Islands.NOAA's...

  18. NOAA ESRI Geotiff- 1m Multibeam Bathymetry of St. Croix (Buck Island), US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains an ESRI Geotiff with 1 meter cell size representing the bathymetry of the north shore of St. Croix (Buck Island), US Virgin Islands.NOAA's...

  19. NOAA TIFF Graphic- 0.5m Backscatter Mosaic of St. Croix (Buck Island), US Virgin Islands, 2005 (NCEI Accession 0131860)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the north shore of Buck Island, St. Croix, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team...

  20. GeoTIFF of 3x3 m Bathymetry for Buck Island, St. Croix, 2011, UTM 20N NAD83 (NCEI Accession 0131858)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a LiDAR (Light Detection & Ranging) 3x3 meter resolution bathymetric surface for an area including and surrounding Buck Island Reef...

  1. GeoTIFF of 3x3 m Relative Reflectivity for Buck Island, St. Croix, 2011, UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a LiDAR (Light Detection & Ranging) 3x3 meter resolution relative seafloor reflectivity surface for an area including and surrounding Buck...

  2. GeoTIFF of 3x3 m Relative Reflectivity for Buck Island, St. Croix, 2011, UTM 20N NAD83 (NCEI Accession 0131858)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a LiDAR (Light Detection & Ranging) 3x3 meter resolution relative seafloor reflectivity surface for an area including and surrounding Buck...

  3. NOAA ESRI Grid- 5m Multibeam Bathymetry of St. Croix (Buck Island), US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains an ESRI Grid with 5 meter cell size representing the bathymetry of the north shore of St. Croix (Buck Island), US Virgin Islands.NOAA's...

  4. NOS ESRI Grid, Unified 10m Multibeam Bathymetry La Parguera, Puerto Rico and Buck Island, St. Croix 2006: Project NF-06-03, UTM 20 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified ESRI Grid with 10 meter cell size representing the bathymetry of selected portions of seafloor around La Parguera, P.R. and Buck...

  5. Dual Buck Hybrid Cascaded Multilevel Inverter%复合型级联多电平双buck式逆变器

    Institute of Scientific and Technical Information of China (English)

    嵇保健; 洪峰; 张广明

    2011-01-01

    采用不同级联单元构建的复合型结构成为级联多电平逆变器电路重要的研究与发展方向。为此,提出了一种新颖的复合型级联多电平双buck逆变器结构。该逆变器引入双buck电路作为基本组成单元,由双buck电路和桥式电路级联构成,发挥各自优点;并采用开环工频控制和滞环电流脉宽调制(PWM)控制相结合的控制方案。其中,双buck电路采用PWM控制,完成输出波形闭环控制,充分利用双buck电路无桥臂直通、无开关器件体二极管反向恢复、适宜高频化的特点;而桥式电路单元开关管在整个工频周期仅开关一次,输出阶梯合成波(三电平时为%A dual buck hybrid cascaded multilevel inverter is presented, and a novel dual buck circuit is introduced into this inverter as the basic cascaded cell. Then, the inverter is made of one dual buck cell and several bridge cells. The merits of dual buck circuit and bridge circuit are remained in this hybrid inverter. And a simple control method composed of low working-frequency switch control and hysteretic current pulse width modulate (PWM) control is adopted. This method is easy to be accomplished. The main cascaded part of the inverter which is modulated by hysteretic current PWM close-loop control method is the dual buck cell. Dual buck circuit is a highly efficient and reliable topology which overcomes the shoot-through problem in traditional bridge inverter, and its switches and diodes can be designed respectively. The other cascaded parts of inverter are all bridge cells, working in a working-frequency switch mode and providing main sector of output voltage. Low frequency and high voltage pressure components can be used as switches of bridge cell. This inverter remains the merits of cascaded multilevel inverter that the harmonic content of output voltage is low, so the filter can be simplified, and its reliability and efficiency are improved.

  6. Collision Bifurcations and Chaos in Buck-Boost Converter with Ramp Compensation%具有斜坡补偿的Buck-Boost变换器的碰撞分岔现象及混沌

    Institute of Scientific and Technical Information of China (English)

    毕玉春; 汪小锋; 刘立生

    2010-01-01

    为了深入研究具有斜坡补偿的Buck-Boost变换器的碰撞分岔现象及混沌,导出了电流模式控制Buck-Boost变换器运行轨道转移时的两个边界方程,从而建立了具有两个边界的三段光滑非线性离散迭代二维映射方程,并通过数值仿真得到了输入电压、斜坡补偿电流的斜率和负载电阻R变化时的动力学行为分布图.

  7. BLDCM Control System Based on Buck-Boost Converter%基于Buck-Boost变换器驱动的无刷直流电动机控制系统

    Institute of Scientific and Technical Information of China (English)

    孟武胜; 王波; 何博

    2011-01-01

    An improved topology of brushless DC motor drive with a Buck-Boost converter before 3 phase inverter,The motor can be controlled by technique-multi-loop. This method can reduce switching losses,the inverter size and cost. Effectiveness and feasibility of the proposed control method was verified by MATLAB/Simulink.%提出在无刷直流电动机的驱动三相逆变桥的输入端加前级降压-升压(Buck-Boost)变换器,采用转速和直流母线电流的多环反馈控制方法实现电机的控制.该方法减少了开关损耗,逆变器尺寸和成本.通过MAT-LAB/Simulink仿真验证了该方法的有效性和可行性.

  8. Study of Bifurcation and Chaos in the Current-Mode Controlled Buck-Boost DC-DC Converter (I) --Modeling and Simulation%Buck-BOOst DC-DC变换器中分叉与混沌问题的研究(Ⅰ)--建模与仿真

    Institute of Scientific and Technical Information of China (English)

    吴捷; 刘明建; 杨苹

    2002-01-01

    This paper studies the bifurcation and chaos in current-mode controlled Buck-Boost converter. The discrete model for Buck-Boost converter in continuous conduction mode (CCM) is derived. The bifurcation and chaos phenomena of Buck-Boost converter have been investigated with input voltage E, reference current Iref, resistor R, inductor L and capacitor C as bifurcation parameters.%研究了电流控制型Buck-Boost变换器中的分叉与混沌问题.首先,对连续模式下的Buck-Boost变换器建立了离散数学模型,在此基础上,在输入电压E、参考电流Iref、电阻R、电感L和电容C等分叉参数作用下,通过数值方法对Buck-Boost变换器中的分叉与混沌进行了详细的仿真研究.仿真研究结果表明:Buck-Boost变换器具有丰富的非线性行为--分叉与混沌,随着各个分叉参数的变化系统会遵循倍周期分叉的规律走向混沌.

  9. 电流型Buck-Boost变换器的分岔频率相关性的验证%Verification of Frequency Correlation for Bifurcation of Current-Mode Controlled Buck-Boost Converters

    Institute of Scientific and Technical Information of China (English)

    李磊; 金爱娟; 李少龙

    2012-01-01

    PWM型Buck-Boost功率变换器的频标可用于预测不同频率运行下的第一个分岔点.本论文首先推导出功率变换器新型频率的相关性.这是在高频工作下由仿真实验结果验证得到的.

  10. Wind-Photovoltaic Hybrid Double-Input Buck-Boost DC/DC Converter%风光互补双输入Buck-Boost直流变换器的研究

    Institute of Scientific and Technical Information of China (English)

    廖志凌; 徐艳杰; 施卫东

    2014-01-01

    Instability and intermittency are two main drawbacks of independent solar energy generation. Therefore, it is essential to use a double-input DC/DC converter, which combines wind with solar to form a hybrid energy system. The paper proposes a new double-input Buck-Boost DC/DC converter with the following advantages: simple circuit, high voltage gain, and allowance of individual or simultaneous power delivery of the two sources. The operation principle of the double-input Buck-Boost DC/DC converter is analyzed, and the steady-state relation between convert input and output is presented. Finally, simulation results with PSPICE software are used to verify the theoretical analysis.%采用双输入直流变换器将太阳能和风能联合构成双输入供电系统,可避免独立光伏发电系统电力供应不稳定和不连续的缺点。本文提出一种新的双输入Buck-Boost直流变换器,具备电路结构简单、电压增益高特点,联合供电系统既可同时向负载供电,又可分体单独向负载供电。分析双输入Buck-Boost直流变换器的工作原理,给出变换器的输入/输出稳态关系式,并通过PSPICE软件进行仿真。仿真结果验证了理论分析的正确性。

  11. Application of Boost-Buck DC/DC Converter with Pure Digital Control%全数字控制B00st-Buck DC/DC变换器的应用

    Institute of Scientific and Technical Information of China (English)

    沈文轩; 吕承明

    2001-01-01

    讨论了实现全数字控制Boost-Buck DC/DC变换器的主电路拓扑结构、控制电路原理、软件控制方案.该变换器具有简单、实用、可靠的优点,被成功地应用在直流屏中作为220V直流母线.

  12. 基于ARM控制的交流BUCK-BOOST电路分析与设计%The Analysis of AC BUCK-BOOST Circuit Based on ARM Control and Its Design

    Institute of Scientific and Technical Information of China (English)

    刘文江; 张晓军; 王旭光

    2006-01-01

    提出和设计了一种新型BUCK-BOOST AC-AC变换电路,详细阐述了其结构和工作原理.该电路采用ARM嵌入式处理器和先进的控制策略,实现了全数字控制.实验结果表明,该电路具有很好的调压效果.

  13. Nonlinear Behavior Research of Current-Mode Controlled Buck-Boost Converters%电流模式控制Buck-Boost变换器非线性行为研究

    Institute of Scientific and Technical Information of China (English)

    谢玲玲; 龚仁喜; 王旷; 卓浩泽

    2010-01-01

    首先建立了电流反馈型Buck-Boost变换器在连续导电模式和不连续导电模式下的离散迭代数学模型,根据稳定性判据得出系统的稳定工作区域.在反馈系数K、输入电压V电感L等为分岔参数作用下,利用数值方法对Buck-Boost变换器中的非线性行为进行了详细的仿真研究.仿真研究和理论分析的结果吻合得很好,研究结果表明:Buck-Boost变换器在这两种工作模式下都是强非线性的,运行时会呈现出分岔、混沌等非线性现象.

  14. Modeling and Simulation of a Buck-Boost Converter Based on Injected-Absorbed-Current Method%基于注吸电流法的Buck-Boost变换器建模与仿真

    Institute of Scientific and Technical Information of China (English)

    李奇南; 凌跃胜

    2006-01-01

    该文详细介绍了注吸电流法的建模思想和步骤,并应用注吸电流法建立了工作在电感电流断续(DCM)模式下的Buck-Boost变换器数学模型.对Buck-Boost变换器及其PI调节器构成的闭环控制系统进行了分析研究.应用Simulink\\SimPowerSystem模块,建立了该系统的Matlab仿真模型,并进行了相应的仿真分析.仿真结果表明,所得Buck-Boost变换器数学模型的精确性和可用性可以满足要求,能够真实反映该系统的动、静态性能.满意的仿真结果与理论分析取得了一致,验证了该模型的正确性.

  15. 基于模型的Buck-Boost变换器协同无源控制%The Model-Based Synergetic and Passivity Control of Buck-Boost Converter

    Institute of Scientific and Technical Information of China (English)

    李红梅; 叶帮红

    2016-01-01

    为了改善Buck-Boost变换器的动态性能和静态性能,基于无源控制实现变换器电感电流期望值的实时观测,再与协同控制相结合得出控制律,提出了协同无源控制的Buck-Boost变换器实现其高性能控制并使之兼具强鲁棒性.为了简化控制器结构,选取协同控制宏变量时未引入积分环节,易于实时实现.最后,采用基于模型设计的开发流程和自动代码生成技术,开发协同无源控制的Buck-Boost变换器样机,通过系统的仿真研究和样机的实验测试,验证该变换器的动态和静态控制性能.

  16. Modeling and dynamics analysis of the fractional-order Buck-Boost converter in continuous conduction mode

    Institute of Scientific and Technical Information of China (English)

    Yang Ning-Ning; Liu Chong-Xin; Wu Chao-Jun

    2012-01-01

    In this paper,the fractional-order mathematical model and the fractional-order state-space averaging model of the Buck-Boost converter in continuous conduction mode (CCM) are established based on the fractional calculus and the Adomian decomposition method.Some dynamical properties of the current-mode controlled fractional-order BuckBoost converter are analysed.The simulation is accomplished by using SIMULINK.Numerical simulations are presented to verify the analytical results and we find that bifurcation points will be moved backward as α and β vary.At the same time,the simulation results show that the converter goes through different routes to chaos.

  17. Effects of bio-stimulation induced by the presence of buck on reproductive performance of rabbit does

    Directory of Open Access Journals (Sweden)

    M.L. Alicata

    2011-03-01

    Full Text Available Over the last few years, bio-stimulation methods have aroused interest as an alternative ways of employing exogenous gonadotropins to improve the sexual receptivity of lactating does and, consequently, the overall productivity of rabbit farms (Theau-Clement, 2000. Among the possible stimulation methods, the so called “buck effect” has been little investigated. The buck effect, understood as the visual, auditory, olfactory and tactile contact between female and male, following a period of separation from the male, is known to be effective in ewes and sows in stimulating and synchronizing oestrus. The existence of stimulus of an olfactory nature has also been established in rabbits. In fact, the pheromones secreted by the sebaceous glands in males have been shown to induce sexual maturity in young female rabbits (Frank, 1966. Moreover, in nulliparous rabbit does, the presence of males contributes to an increased acceptance to mating.......

  18. Fast-Scale and Slow-Scale Subharmonic Oscillation of Valley Current-Mode Controlled Buck Converter

    Institute of Scientific and Technical Information of China (English)

    ZHOU Guo-Hua; XU Jian-Ping; BAO Bo-Cheng; ZHANG Fei; LIU Xue-Shan

    2010-01-01

    @@ A valley current-mode (VCM) controlled buck converter with current source load (CSI) has complex phenomena of fast-scale and slow-scale subharmonic oscillations.The piecewise smooth switching model of the VCM controlled buck converter with CSI is established.It is found that attractive regions of fast-scale and slow-scale subharmonic oscillations exist in the bifurcation diagram,and two tori exist in the corresponding Poincaré mapping.The research results by time-domain simulation indicate that U-type subharmonic oscillation (SO) constituted by SO and frequency-reduced subharmonic oscillation (FSO) exists in inductor current,and sine-type SO constituted by fast scale and low scaie exists in output voltage respectively.Experimental results are given to verify the analysis and simulation results.

  19. Mercury Exposure in Piscivorous Birds at the Carson River (NV) Superfund Site, 1997-2006

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The persistence and degree of mercury contamination of the lower Carson River system (LCRS) have led to placement of a portion of the Carson River Basin (including...

  20. 76 FR 1154 - Operating Industries, Inc., Superfund Site, Monterey Park, CA; Notice of Proposed CERCLA...

    Science.gov (United States)

    2011-01-07

    ...., Beren Corporation, Beylik Drilling, Inc., Big Penny Car Wash General Partnership, Bimbo Bakeries USA... Metal Finishing Corp., dba Barron Anodizing, Cackle Fresh Egg Farms, Inc., Califone International, Inc...-interest to Lightolier, Inc., Geo Drilling Fluids, Inc., George O. Ladner, Jr., Trustee, Trepanier...