Note: This page contains sample records for the topic stack gas particulate from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

Cooler and particulate separator for an off-gas stack  

DOEpatents

This report describes an off-gas stack for a melter, furnace or reaction vessel comprising an air conduit leading to two sets of holes, one set injecting air into the off-gas stack near the melter plenum and the second set injecting air downstream of the first set. The first set injects air at a compound angle, having both downward and tangential components, to create a reverse vortex flow, counter to the direction of flow of gas through the stack and also along the periphery of the stack interior surface. Air from the first set of holes prevents recirculation zones from forming and the attendant accumulation of particulate deposits on the wall of the stack and will also return to the plenum any particulate swept up in the gas entering the stack. The second set of holes injects air in the same direction as the gas in the stack to compensate for the pressure drop and to prevent the concentration of condensate in the stack. A set of sprayers, receiving water from a second conduit, is located downstream of the second set of holes and sprays water into the gas to further cool it.

Wright, G.T.

1991-04-08

2

On-line measurement of stack-gas particulate radionuclides  

SciTech Connect

This paper describes an advanced process-monitoring system for the automatic sample collection, analysis, reporting, and alarming of the concentration of long-lived radionuclides in nuclear process stack-gas effluents. This system, the Moving Filter Radioactive Aerosol Monitor, collects particulates in a conditioned sampling chamber, under computer control, for subsequent and separate alpha and beta counting and analysis. The alpha measurement is performed with a solid-state surface-barrier detector. Beta analysis is performed with a phoswich scintillation detector. A unique alpha-energy analysis program that provides automatic energy calibration and lowered detection limits for plutonium in the presence of high quantities of interfering /sup 212/Bi/Po is described. The /sup 212/Bi/Po alpha results are further used to monitor system quality and to compensate for the radon daughter beta components in the beta system. Results of the system calibration and detection limits are also presented. 8 refs., 6 figs.

Stong, F.S.; Troyer, G.L.; Criddle, J.D. Jr.

1987-11-01

3

On-line measurement of stack gas particulate radionuclides  

Microsoft Academic Search

Stack gases from nuclear facilities can contain both natural and man-made radionuclides. Interferences from natural radon daughters limit the detection capability of common radiation measurement methods. An improved system using on-line multichannel analyzers, alpha energy spectroscopy, gamma-ray analysis, radon-compensated gross beta counting, and automated data reduction is presented. This system provides accurate determination of certain stack effluent fine particulates as

F. S. Stong; G. L. Troyer; J. D. Jr. Criddle

1987-01-01

4

Hand calculator programs for stack particulate tests  

SciTech Connect

Those familiar with particulate stack testing understand that a great deal of number-crunching is necessary to generate end results. Two hand calculator programs, one designed for a Texas Instruments Programmable 57 and the other for a Hewlett-Packard 33E, have been developed to ease this workload and provide quick turnaround when results are required in a hurry. These two programs calculate all the variables surrounding a stack test except isokinetics. As such these programs are intended to be used as a supplement to, and not a replacement of, more advanced computer programs that calculate all the variables and provide hard copy documentation of raw data and end results. Each calculator program has been divided into two parts. The first part uses the equations presented in EPA's Reference Method 5-Determination of Particulate Emissions from Stationary Sources to calculate particulate concentration, dry and wet gas volumes and moisture content. The second part uses the results of the first part and equations presented in EPA Reference Method 2-Determination of Stack Gas Velocity and Volumetric Flow Rate to calculate volumetric flow rate, emission rate and velocity.

Fay, W.A.; Jones, B.J.

1983-01-01

5

Hand calculator programs for stack particulate tests  

Microsoft Academic Search

Those familiar with particulate stack testing understand that a great deal of number-crunching is necessary to generate end results. Two hand calculator programs, one designed for a Texas Instruments Programmable 57 and the other for a Hewlett-Packard 33E, have been developed to ease this workload and provide quick turnaround when results are required in a hurry. These two programs calculate

W. A. Fay; B. J. Jones

1983-01-01

6

STACK GAS REHEAT EVALUATION  

EPA Science Inventory

The report gives results of technical and economic evaluations of stack gas reheat (SGR) following wet flue gas desulfurization (FGD) for coal-fired power plants. The evaluations were based on information from literature and a survey of FGD users, vendors, and architect/engineer ...

7

Stack Gas Reheat Evaluation.  

National Technical Information Service (NTIS)

The report gives results of technical and economic evaluations of stack gas reheat (SGR) following wet flue gas desulfurization (FGD) for coal-fired power plants. The evaluations were based on information from literature and a survey of FGD users, vendors...

W. R. Menzies C. A. Muela G. P. Behrens

1980-01-01

8

FIELD EVALUATION OF AN AUTOISOKINETIC STACK PARTICULATE SAMPLING SYSTEM  

EPA Science Inventory

The performance of a prototype autoisokinetic stack particulate sampling system, designed to maintain automatically isokinetic sampling conditions, was evaluated in field tests at stationary sources. Tests were conducted to determine the operating limits and characteristics of th...

9

Stack gas treatment  

DOEpatents

Hot stack gases transfer contained heat to a gravity flow of pebbles treated with a catalyst, cooled stacked gases and a sulfuric acid mist is withdrawn from the unit, and heat picked up by the pebbles is transferred to air for combustion or other process. The sulfuric acid (or sulfur, depending on the catalyst) is withdrawn in a recovery unit.

Reeves, Adam A. (P.O. Box 781, Rifle, CO 81650)

1977-04-12

10

ETR WASTE GAS STACK. ABOVE GROUND DUCTWORK AND ETR STACK, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

ETR WASTE GAS STACK. ABOVE GROUND DUCTWORK AND ETR STACK, CLOSER VIEW. PERSONNEL LADDER AND CIRCULAR WORK PLATFORM MIDWAY UP STACK. CAMERA FACES NORTH. INL NEGATIVE NO. HD42-7-2. Mike Crane, Photographer, 3/2004 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

11

A new method for the characterisation and quantitative speciation of base metal smelter stack particulates.  

PubMed

Base metal smelters may be a source of particulates containing metals of environmental concern released to the atmosphere. Knowledge of the quantitative chemical speciation of particulate releases from base metal smelters will be of value in smelter emission fingerprinting, site-specific risk assessments, predictions of the behaviour of smelter stack particulates released to the environment and in resolving liability issues related to current and historic releases. Accordingly, we have developed an innovative approach comprising bulk chemical analysis, a leaching procedure, X-ray diffraction analysis and scanning electron microscopy/electron probe microanalysis characterisation in a step-wise apportioning procedure to derive the quantitative speciation of particulate samples from the stacks of three copper smelters designated as A, B and C. For the A smelter stack particulates, the major calculated percentages were 29 CuSO(4), 20 ZnSO(4).H(2)O, 13 (Cu(0.94)Zn(0.06))(2)(AsO(4))(OH), 11 PbSO(4) and four As(2)O(3). For the B smelter stack particulates, the primary calculated percentages were 20 ZnSO(4).H(2)O, 20 PbSO(4), 12 CuSO(4) and nine As(2)O(3). Finally, we calculated that the C smelter stack particulates mostly comprised 34 ZnSO(4).H(2)O, 19 (Cu(0.84)Zn(0.16))(AsO(3)OH), 11 PbSO(4), 10 As(2)O(3) and nine Zn(3)(AsO(4))(2). Between 56% and 67% by weight of the smelter stack particulates, including the As, was soluble in water. For these and other operations, the data and approach may be useful in estimating metals partitioning among water, soil and sediment, as well as predictions of the effects of the stack particulates released to the environment. PMID:20676929

Skeaff, James M; Thibault, Yves; Hardy, David J

2010-07-30

12

Stack Gas Scrubber Makes the Grade  

ERIC Educational Resources Information Center

|Describes a year long test of successful sulfur dioxide removal from stack gas with a calcium oxide slurry. Sludge disposal problems are discussed. Cost is estimated at 0.6 mill per kwh not including sludge removal. A flow diagram and equations are included. (GH)|

Chemical and Engineering News, 1975

1975-01-01

13

Measurement of the influence of a cement kiln stack on a surrounding residential community by injection of an identification particulate.  

PubMed

An identification particulate, barium sulfate, was injected into the kiln stack of a large cement plant in order to determine the effect of the particulate effluent of this stack on the immediately surrounding residential community. Meteorological conditions at the time of the injection favored deposition of the stack plume fallout directly over the location of a 7.75-km2 area in which both dustfall and suspended particle samplers were located. Dustfall data are reported for a 24-hour period to permit collection of all possible BaSO4-relatable stack emission. Collected particulate was analyzed for calcium and barium by atomic absorption spectroscopy. Collected dustfall particulates showed no stack effluent effect; collected suspended particulates exhibited a content of stack-relatable material in the amount of 1% of the total observed weight. PMID:1111265

Warner, P O; Jackson, J O; Saad, L; Greenberg, A

1975-01-01

14

In-Stack Condensible Particulate Matter Measurements and Issues  

Microsoft Academic Search

Particulate matter (PM) emitted from fossil fuel-fired units can be classified as either filterable or condensible PM. Condensible PM typically is not measured because federal and most state regulations do not require sources to do so. To determine the magnitude of condensible PM emissions relative to filterable PM emissions and to better understand condensible PM measurement issues, a review and

Louis A. Corio; John Sherwell

2000-01-01

15

WASTE GAS STACKS, CONTEXTUAL VIEW. ABOVEGROUND DUCTWORK LEADS TO ETR ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

WASTE GAS STACKS, CONTEXTUAL VIEW. ABOVE-GROUND DUCTWORK LEADS TO ETR STACK. MTR STACK AT LEFT OF VIEW. CAMERA FACING NORTH. INL NEGATIVE NO. HD42-7-1. Mike Crane, Photographer, 3/2004 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

16

Particulate hot gas stream cleanup technical issues  

SciTech Connect

The analyses of hot gas stream cleanup particulate samples and descriptions of filter performance studied under this contract were designed to address problems with filter operation that have been linked to characteristics of the collected particulate matter. One objective of this work was to generate an interactive, computerized data bank of the key physical and chemical characteristics of ash and char collected from operating advanced particle filters and to relate these characteristics to the operation and performance of these filters. The interactive data bank summarizes analyses of over 160 ash and char samples from fifteen pressurized fluidized-bed combustion and gasification facilities utilizing high-temperature, high pressure barrier filters.

Pontius, D.H.; Snyder, T.R.

1999-09-30

17

Stack gas reheat for wet flue gas desulfurization systems. Final report  

Microsoft Academic Search

The objective of the unit study was to provide the Electric Power Research Institute with detailed and coordinated information on stack gas reheat for wet scrubbers at power plants. One of the major problems to be dealt with in the wet scrubbing processes is the need for stack gas reheat. In many wet scrubber installations, the stack gas reheat system

P. S. K. Choi; S. G. Bloom; H. S. Rosenberg; S. T. DiNovo

1977-01-01

18

Stack gas disposal extracts: March 1947--January 1952  

SciTech Connect

This document presents information on stack gas disposal which was extracted from weekly or monthly technical progress letters published during the period from March 1947 through January 1952. These extracts were taken from documents currently available on the Hanford Site. Selected extracts have been retyped because the reproductions made from some of the aging microfilm are nearly illegible. This chronology of stack gas disposal information was developed specifically for use by the Hanford Environmental Dose Reconstruction (HEDR) staff.

Cleavenger, P.M.; Gydesen, S.P. (comps.)

1989-10-01

19

Process for off-gas particulate removal and apparatus therefor  

DOEpatents

In the event of a breach in the off-gas line of a melter operation requiring closure of the line, a secondary vessel vent line is provided with a particulate collector utilizing atomization for removal of large particulates from the off-gas. The collector receives the gas containing particulates and directs a portion of the gas through outer and inner annular channels. The collector further receives a fluid, such as water, which is directed through the outer channel together with a second portion of the particulate-laden gas. The outer and inner channels have respective ring-like termination apertures concentrically disposed adjacent one another on the outer edge of the downstream side of the particulate collector. Each of the outer and inner channels curves outwardly away from the collector's centerline in proceeding toward the downstream side of the collector. Gasflow in the outer channel maintains the fluid on the channel's wall in the form of a "wavy film," while the gas stream from the inner channel shears the fluid film as it exits the outer channel in reducing the fluid to small droplets. Droplets formed by the collector capture particulates in the gas stream by one of three mechanisms: impaction, interception or Brownian diffusion in removing the particulates. The particulate-laden droplets are removed from the fluid stream by a vessel vent condenser or mist eliminator.

Carl, Daniel E. (Orchard Park, NY)

1997-01-01

20

Sampling probe for stack gas monitoring system  

SciTech Connect

A tube closed at the end by plugs having axial bores therein and which support a hollow, porous walled cylinder concentrically within the tube to form a conduit interconnecting the plug bores while allowing a clearance space between the cylinder outer wall and the tube inner wall. A combined ejector-blowback valve is secured to one plug externally of the tube for inducing gas flow through the plug bores and cylinder in one valve position and for reversing flow through the plug bores and cylinder in a second valve position to dislodge and discharge adherent material. The probe is mounted with the end opposite the ejector-blowback valve extending into the gas stream to be sampled. Gas samples are withdrawn from the clearance space surrounding the cylinder. The probe is constructed substantially entirely of corrosion and temperature resistant ceramic material.

Wood, R.D.

1983-04-12

21

Particulate Hot Gas Stream Cleanup Technical Issues  

SciTech Connect

The characteristics of entrained particles generated by advanced coal conversion technologies and the harsh flue gas environments from which these particles must be removed challenge current ceramic barrier filtration systems. Measurements have shown that the size distribution, morphology, and chemical composition of particles generated by pressurized fluidized-bed combustion (PFBC) and gasification processes differ significantly from the corresponding characteristics of conventional pulverized-coal ash particles. The entrained particulate matter from these advanced conversion technologies often comprise fine size distributions, irregular particle morphologies, high specific surface areas, and significant proportions of added sorbent material. These characteristics can create high ash cohesivity and high pressure losses through the filter cakes. In addition, the distributions of chemical constituents among the collected particles provide local, highly concentrated chemical species that promote reactions between adjacent particles that ultimately cause strong, nodular deposits to form in the filter vessel. These deposits can lead directly to bridging and filter element failure. This project is designed to address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic filter elements. The activities conducted under Task 1, Assessment of Ash Characteristics, are discussed in this paper. Activities conducted under Task 2, Testing and Failure Analysis of Ceramic Filters, are discussed in a separate paper included in the proceedings of the Advanced Coal-Based Power and Environmental Systems `97 Conference. The specific objectives of Task I include the generation of a data base of the key characteristics of Hot Gas Stream Cleanup (HGCU) ashes collected from operating advanced particle filters (APFS) and the identification of relationships between HGCU ash properties and the operation and performance of APFS. During the past year, particulate samples have been characterized from the DOE/FETC Modular Gas Cleanup Rig (MGCR), the Transport Reactor Demonstration Unit (TRDU) located at the University of North Dakota Energy and Environmental Research Center (UNDEERC), the Power Systems Development Facility (PSDF), and gasification studies conducted by Herman Research Pty. Ltd. (HRL) of Melbourne, Australia. This paper discusses these analyses and also presents a coherent mechanism describing how and why consolidated ash deposits form in PFBC filter vessels. This description is based on site observations made at the Tidd PFBC, field and laboratory analyses of ashes and nodules collected from Grimethorpe, Tidd and Karhula, and a review of literature describing eutectic formation, sintering, and consolidation of boiler tube deposits.

Potius, D.; Snyder, T.

1997-07-01

22

ETR STACK, TRA753. ABOVE GROUND DUCTING CARRIES WASTE GAS FROM ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

ETR STACK, TRA-753. ABOVE GROUND DUCTING CARRIES WASTE GAS FROM ETR CUBICLES TO STACK. MTR STACK AND FAN HOUSE ARE TO LEFT OF ETR STACK. CAMERA FACES EAST. INL NEGATIVE NO. 56-3797. Jack L. Anderson, Photographer, 11/26/1956 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

23

Particulate hot gas stream cleanup technical issues  

SciTech Connect

This is the eleventh in a series of quarterly reports describing the activities performed under Contract No. DE-AC21-94MC31160. Analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic bed filter elements. Task 1 is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFS) and to relate these ash properties to the operation and performance of these filters. Task 2 concerns testing and failure analysis of ceramic filter elements. Under Task 1 during the past quarter, analyses were completed on samples obtained during a site visit to the Power Systems Development Facility (PSDF). Analyses are in progress on ash samples from the Advanced Particulate Filter (APF) at the Pressurized Fluidized-Bed Combustor (PFBC) that was in operation at Tidd and ash samples from the Pressurized Circulating Fluid Bed (PCFB) system located at Karhula, Finland. An additional analysis was performed on a particulate sample from the Transport Reactor Demonstration Unit (TRDU) located at the University of North Dakota Energy and Environmental Research Center. A manuscript and poster were prepared for presentation at the Advanced Coal-Based Power and Environmental Systems `97 Conference scheduled for July 22 - 24, 1997. A summary of recent project work covering the mechanisms responsible for ash deposit consolidation and ash bridging in APF`s collecting PFB ash was prepared and presented at FETC-MGN in early July. The material presented at that meeting is included in the manuscript prepared for the Contractor`s Conference and also in this report. Task 2 work during the past quarter included mechanical testing and microstructural examination of Schumacher FT20 and Pall 326 as- manufactured, after 540 hr in service at Karhula, and after 1166 hr in service at Karhula. Key test results showed that property degradation occurred during service at Karhula but less degradation than was seen in Schumacher F40 and Pall 442T. Creep continues to be observed in tests at 1600 `F and above and was observed at 1562 `F in service at Karhula. Microstructural evaluations of FT20 and 326 materials have shown that the behavior of these materials is controlled by the ceramic binders and that the binders are still glass limited. These results were presented in a poster session and a paper written for the Advanced Coal-Based Power and Environmental Systems `97 Conference.

NONE

1998-09-01

24

Degradation of polycyclic aromatic hydrocarbons during simulated stack gas sampling  

SciTech Connect

The formation of sampling artifacts due to exposure to NO, NO/sub 2/, SO/sub 2/, and SO/sub 3/ has been studied. The sampling method was tested in a thermostatic oven attached to a smoke generator and involves filtration of particles at stack gas temperature, condensation, and adsorption on Amberlite XAD-2. A substantial degradation of reactive PAH took place in all steps during sampling. The reactivity increased in the presence of acid. The reaction products formed included 9-nitroanthracene, 1-nitropyrene, 10-nitrobenz(a)anthracene, nitrobenzo(a)pyrene, and several polycyclic ketones, aldehydes, and guinones, but the main reaction products have not been identified so far.

Brorstroem-Lunden, E.; Lindskog, A.

1985-01-01

25

Fuel cell stack with an integral ejector for reactant gas recirculation  

Microsoft Academic Search

A stack of fuel cells operating on gaseous reactants includes an ejector in integral heat exchange relationship with the stack for recirculating one of the reactant gases through the cells of the stack. The recirculating reactant is continuously heated by waste heat from the cells as it recirculates thereby preventing condensation of water from the recirculating reactant gas and thereby

Grasso

1976-01-01

26

40 CFR Table 4 to Subpart Jjjjjj... - Performance (Stack) Testing Requirements  

Code of Federal Regulations, 2013 CFR

...moisture content of the stack gas Method 4 in...particulate matter emission concentration...moisture content of the stack gas Method 4 in...Measure the mercury emission concentration ...moisture content of the stack gas Method 4 in...the carbon monoxide emission concentration...

2013-07-01

27

CAPSULE REPORT: BAHCO FLUE GAS DESULFURIZATION AND PARTICULATE REMOVAL SYSTEM  

EPA Science Inventory

This capsule report describes a Research-Cottrell/Bahco scrubber module for sulfur dioxide and particulate emission control located at the central heat plant of Rickenbacker Air Force Base. he report also describes flue gas desulfurization technology using any fuel, including hig...

28

Stack Gas Reheat for Wet Flue Gas Desulfurization Systems. Final Report.  

National Technical Information Service (NTIS)

The objective of the unit study was to provide the Electric Power Research Institute with detailed and coordinated information on stack gas reheat for wet scrubbers at power plants. One of the major problems to be dealt with in the wet scrubbing processes...

H. S. Rosenberg P. S. K. Choi S. G. Bloom S. T. DiNovo

1977-01-01

29

Measurement of Opacity and Particulate Emissions With an On-Stack Transmissometer  

ERIC Educational Resources Information Center

|An on-stack transmissometer system, that is designed to provide a precision measurement of the opacity of visible emissions, is described. The sources of error in opacity measurements with regard to recent Environmental Protection Agency emission monitoring requirements and planned specifications are discussed. (Author/BT)|

Beutner, Heinz P.

1974-01-01

30

Characterization of cotton gin total particulate matter emissions based on EPA stack sampling methodologies  

Technology Transfer Automated Retrieval System (TEKTRAN)

A project to characterize cotton gin emissions in terms of stack sampling was conducted during the 2008 through 2011 ginning seasons. The impetus behind the project was the urgent need to collect additional cotton gin emissions data to address current regulatory issues. EPA AP-42 emission factors ar...

31

Spectral emission measurements from planar mixtures of gas and particulates  

NASA Astrophysics Data System (ADS)

An experimental system is developed that forms a hot layer of gas and particulates flowing through a test section with cooled walls. The test section forms a one-dimensional planar layer, allows intrusive probes to characterize the medium in terms of particle loading and temperature, and allows radiometric measurements of the normally directed spectral energy emitted from the medium. Gas flow, gas composition, and particle flow are controlled. An experimental investigation is undertaken yielding spectral normally directed emittance data obtained from a well-characterized layer containing gaseous constituents of carbon dioxide and nitrogen, and solid particles of BNi-2, a boron nickel alloy. Emittance data are presented and exhibit the effects of particulate scattering, including the extension of the 4.3 microns carbon dioxide band wings. Emittance data are compared to analytical predictions.

Skocypec, R. D.; Walters, D. V.; Buckius, R. O.

1987-02-01

32

Particulate Matter Stack Emission Compliance Test Procedure for Fuel Burning Units.  

ERIC Educational Resources Information Center

|This publication details the particulate matter emissions test procedure that is applicable for conducting compliance tests for fuel burning units required to be tested under Sub-section 7 of Regulation II (1972) as established by the state of West Virginia Air Pollution Control Commission. The testing procedure is divided into five parts:…

West Virginia Air Pollution Control Commission, Charleston.

33

Particulate Hot Gas Stream Cleanup Technical Issues  

Microsoft Academic Search

The characteristics of entrained particles generated by advanced coal conversion technologies and the harsh flue gas environments from which these particles must be removed challenge current ceramic barrier filtration systems. Measurements have shown that the size distribution, morphology, and chemical composition of particles generated by pressurized fluidized-bed combustion (PFBC) and gasification processes differ significantly from the corresponding characteristics of conventional

D. Potius; T. Snyder

1997-01-01

34

Weighted stacking for rock property estimation and detection of gas  

Microsoft Academic Search

Amplitude versus offset concepts can be used to generate weighted stacking schemes (here called geo-stack) which can be used in an otherwise standard seismic data processing sequence to display information about rock properties. The Zoeppritz equations can be simplified and several different approximations appear in the literature. They describe the variation of P-wave reflection coefficients with the angle of incidence

G. C. Smith; P. M. Gidlow

1987-01-01

35

Exposure assessment of particulates of diesel and natural gas fuelled buses in silico  

Microsoft Academic Search

Lung deposition estimates of particulate emissions of diesel and natural gas (CNG) fuelled vehicles were studied by using in silico methodology. Particulate emissions and particulate number size distributions of two Euro 2 petroleum based diesel buses and one Euro 3 gas bus were measured. One of the petroleum based diesel buses used in the study was equipped with an oxidation

Mari Pietikäinen; Kati Oravisjärvi; Arja Rautio; Arto Voutilainen; Juhani Ruuskanen; Riitta L. Keiski

2009-01-01

36

PARTICULATE HOT GAS STREAM CLEANUP TECHNICAL ISSUES  

SciTech Connect

This is the fourth annual report describing the activities performed under Task 1 of Contract No. DE-AC21-94MC31160. The analyses of hot gas stream cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. This work is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters and to relate these ash properties to the operation and performance of these filters and their components. This report summarizes characterizations of ash and char samples from pressurized fluidized-bed combustion and gasification facilities. Efforts are under way to develop a method for preserving fragile filter cakes formed on ceramic filter elements. The HGCU data base was formatted for Microsoft Access 97 ® . Plans for the remainder of the project include characterization of additional samples collected during site visits to the Department of Energy / Southern Company Services Power Systems Development Facility and completion and delivery of the HGCU data base.

NONE

1998-11-30

37

PARTICULATE HOT GAS STREAM CLEANUP TECHNICAL ISSUES  

SciTech Connect

This is the fourth annual report describing the activities performed under Task 1 of Contract No. DE-AC21-94MC31160. The analyses of hot gas stream cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. This work is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters and to relate these ash properties to the operation and performance of these filters and their components. This report summarizes characterizations of ash and char samples from pressurized fluidized-bed combustion and gasification facilities. Efforts are under way to develop a method for preserving fragile filter cakes formed on ceramic filter elements. The HGCU data base was formatted for Microsoft Access 97{reg_sign}. Plans for the remainder of the project include characterization of additional samples collected during site visits to the Department of Energy/Southern Company Services Power Systems Development Facility and completion and delivery of the HGCU data base.

NONE

1999-05-05

38

PARTICULATE HOT GAS STREAM CLEANUP TECHNICAL ISSUES  

SciTech Connect

This is the fourth annual report describing the activities performed under Task 1 of Contract No. DE-AC21-94MC31160. The analyses of hot gas stream cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. This work is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters and to relate these ash properties to the operation and performance of these filters and their components. This report summarizes characterizations of ash and char samples from pressurized fluidized-bed combustion and gasification facilities. Efforts are under way to develop a method for preserving fragile filter cakes formed on ceramic filter elements. The HGCU data base was formatted for Microsoft Access 97 ® . Plans for the remainder of the project include characterization of additional samples collected during site visits to the Department of Energy / Southern Company Services Power Systems Development Facility and completion and delivery of the HGCU data base.

None

1999-05-05

39

Stack gas emissions of PCDD\\/Fs from hospital waste incinerators in China  

Microsoft Academic Search

Stack gas samples from 14 domestic-made hospital waste incinerators (HWIs) in China were collected and analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD\\/Fs). The waste burning capacities of the investigated HWIs ranged from 5 to 25tond?1. The stack gas emissions of PCDD\\/Fs from HWIs exhibited a large variation (0.08–31.60ng I-TEQNm?3). Nine incinerators had the emission levels below the current emission standard

Hongcai Gao; Yuwen Ni; Haijun Zhang; Liang Zhao; Ning Zhang; Xueping Zhang; Qing Zhang; Jiping Chen

2009-01-01

40

Boiler Briquette Coal versus Raw Coal: Part I—Stack Gas Emissions  

Microsoft Academic Search

Stack gas emissions were characterized for a steam-generating boiler commonly used in China. The boiler was tested when fired with a newly formulated boiler briquette coal (BB-coal) and when fired with conventional raw coal (R-coal). The stack gas emissions were analyzed to determine emission rates and emission factors and to develop chemical source profiles. A dilution source sampling system was

Su Ge; Zhipeng Bai; Weili Liu; Tan Zhu; Tongjian Wang; Sheng Qing; Junfeng Zhang

2001-01-01

41

Laser-particulate control for open-cycle, coal fired gas turbines  

Microsoft Academic Search

Direct coal-fired gas turbines need efficient high temperature particulate control in order to be an attractive option for the efficient conversion of coal to electrical energy. Particulates in the range of three to ten microns are very difficult to remove and it is, therefore, proposed that they be fragmented into particulates below the threshold size for turbine blade erosion using

T. E. Botts; J. R. Powell

1979-01-01

42

Onset of stacking faults in InP nanowires grown by gas source molecular beam epitaxy  

SciTech Connect

InP nanowires (NWs) were grown by gas source molecular beam epitaxy on InP (111)B substrates, using Au nanoparticles as a growth catalyst. The rod-shaped NWs exhibited hexagonal sidewall facets oriented along the (-211) family of crystal planes for all NW diameters, indicating minimal sidewall growth. Stacking faults, when present, were concentrated near the NW tips, while NWs with lengths less than 300 nm were completely free of stacking faults.

Cornet, D. M.; Mazzetti, V. G. M.; LaPierre, R. R. [Centre for Emerging Device Technologies, McMaster University, Hamilton, Ontario L8S 4 L7 (Canada)

2007-01-01

43

Numerical Simulation of Atmospheric Flow and Stack Gas Diffusion under Building and Complex Terrain Conditions  

NASA Astrophysics Data System (ADS)

A numerical simulation method has been developed to predict atmospheric flow and stack gas diffusion under a neutral stratification condition, considering the buildings and complex terrain located near and relatively far from a stack, respectively. The turbulence closure technique was used for flow calculation, some calculation grids on the ground within a plant area were treated as buildings, and stack gas diffusion was predicted using the Lagrangian particle model. The calculated flow and stack gas diffusion results were compared with those obtained by wind tunnel experiments under a neutral stratification condition, and the features of surface concentration, such as the occurrence of downdraft phenomena behind the buildings, were reproduced by both calculations and wind tunnel experiments. Furthermore, effective stack heights were estimated by the comparison of the surface concentration along the plume axis with those under a flat-plate condition, and it was apparent that the effective stack heights estimated by calculations were almost the same as those obtained by wind tunnel experiments.

Sada, Koichi; Michioka, Takenobu; Ichikawa, Yoichi

44

High efficiency particulate air filter lives in hydrogen fluoride gas environments  

Microsoft Academic Search

Tests of high-efficiency particulate air filters were requested following catastrophic failure of a filter by hydrogen fluoride gas from improper operation in a production line. Operational lives in hydrogen fluoride environments of high-efficiency particulate air filters were determined in statistically designed experiments for three variables. The variables studied were hydrogen fluoride gas concentration, water vapor concentration, and wind speed through

1992-01-01

45

40 CFR 86.120-94 - Gas meter or flow instrumentation calibration; particulate, methanol and formaldehyde measurement.  

Code of Federal Regulations, 2011 CFR

... Gas meter or flow instrumentation calibration; particulate, methanol and formaldehyde... Gas meter or flow instrumentation calibration; particulate, methanol and formaldehyde...instruments shall receive initial and periodic calibrations as follows: (1)(i) Install...

2011-07-01

46

Exposure assessment of particulates of diesel and natural gas fuelled buses in silico.  

PubMed

Lung deposition estimates of particulate emissions of diesel and natural gas (CNG) fuelled vehicles were studied by using in silico methodology. Particulate emissions and particulate number size distributions of two Euro 2 petroleum based diesel buses and one Euro 3 gas bus were measured. One of the petroleum based diesel buses used in the study was equipped with an oxidation catalyst on the vehicle (DI-OC) while the second had a partial-DPF catalyst (DI-pDPF). The third bus used was the gas bus with an oxidation catalyst on the vehicle (CNG-OC). The measurements were done using a transient chassis dynamometer test cycle (Braunschweig cycle) and an Electric Low Pressure Impactor (ELPI) with formed particulates in the size range of 7 nm to 10 microm. The total amounts of the emitted diesel particulates were 88-fold for DI-OC and 57-fold for DI-pDPF compared to the total amount of emitted CNG particulates. Estimates for the deposited particulates were computed with a lung deposition model ICRP 66 using in-house MATLAB scripts. The results were given as particulate numbers and percentages deposited in five different regions of the respiratory system. The percentages of particulates deposited in the respiratory system were 56% for DI-OC, 51% for DI-pDPF and 77% for CNG-OC of all the inhaled particulates. The result shows that under similar conditions the total lung dose of particulates originating from petroleum diesel fuelled engines DI-OC and DI-pDPF was more than 60-fold and 35-fold, respectively, compared to the lung dose of particulates originating from the CNG fuelled engine. The results also indicate that a majority (35-50%) of the inhaled particulates emitted from the tested petroleum diesel and CNG engines penetrate deep into the unciliated regions of the lung where gas-exchange occurs. PMID:19828175

Pietikäinen, Mari; Oravisjärvi, Kati; Rautio, Arja; Voutilainen, Arto; Ruuskanen, Juhani; Keiski, Riitta L

2009-10-13

47

Optical backscatter probe for sensing particulate in a combustion gas stream  

DOEpatents

A system for sensing particulate in a combustion gas stream is disclosed. The system transmits light into a combustion gas stream, and thereafter detects a portion of the transmitted light as scattered light in an amount corresponding to the amount of particulates in the emissions. Purge gas may be supplied adjacent the light supply and the detector to reduce particles in the emissions from coating or otherwise compromising the transmission of light into the emissions and recovery of scattered light from the emissions.

Parks, James E; Partridge, William P

2013-05-28

48

Independent determination of the accuracy of the OSTR stack gas monitor and its operational application  

Microsoft Academic Search

This study was undertaken to determine the accuracy of the stack gas monitor, using techniques which were independent of the monitoring system itself. Samples of argon-41 to be used as the standards in this study were carefully produced in the thermal column of the OSTR and counted on a Ge(Li) detector which was connected to a multichannel analyzer (MCA). As

B. D. Pickett; A. G. Johnson

1982-01-01

49

Heat tracing stack gas sample lines for fossil fuel-fired power stations  

Microsoft Academic Search

Heat tracing has been widely used in power generating facilities for many years, primarily for winterization of pipes containing water or condensates in subfreezing climates. However, there are many process applications for heat tracing that are often overlooked. Some of these applications are reviewed, and attention is focused on analyzing stack gas emissions

P. R. Baen

1991-01-01

50

Effect on Combined Cycle Efficiency of Stack Gas Temperature Constraints to Avoid Acid Corrosion.  

National Technical Information Service (NTIS)

The effect on combined cycle performance of raising the stack gas temperatures to levels high enough to avoid corrosion when burning fuels containing sulfur is presented and discussed. The use of fuels containing sulfur requires that the cold-end heat exc...

J. J. Nainiger

1980-01-01

51

Heat tracing stack gas sample lines for fossil fuel-fired power stations  

SciTech Connect

Heat tracing has been widely used in power generating facilities for many years, primarily for winterization of pipes containing water or condensates in subfreezing climates. However, there are many process applications for heat tracing often overlooked. This paper reviews some of these applications and focuses on analyzing stack gas emissions.

Baen, P.R. (Thermon, San Marcos, TX (US))

1991-03-01

52

Observation of exclusively ?-stacked heterodimer of indole and hexafluorobenzene in the gas phase  

NASA Astrophysics Data System (ADS)

In this study, the structure of the indole . . . hexafluorobenzene dimer has been investigated in the gas phase by using resonant two photon ionzation (R2PI) and IR-UV double resonance spectroscopy combined with quantum chemistry calculations. We have confirmed the presence of exclusively ?-stacked structure of the dimer from both experimental and theoretical IR spectra in the N-H stretching region. Observation of a single stable structure of the dimer has also been verified through 3D potential energy surface scan of the ?-stacked dimer by varying the parallel displacement of the hexafluorobenzene unit simultaneously along the major and minor axes of the indole moiety. ?-stacking interaction is present very often between the tryptophan and phenylalanine residues in proteins. But this interaction has not been observed earlier in the gas phase experiment by studying indole . . . benzene dimer because the N-H group of indole predominately directs towards the N-H . . . ? hydrogen bonded T-shaped structure. The chosen molecular systems in this study not only rule out the possibility of the formation of the N-H . . . ? bound T-shaped dimer but also enable the determination of the structure by probing the N-H group. The ?-stacked indole . . . hexafluorobenzene dimer has a unique structure where the center of the hexafluorobenznene ring is aligned with the center of the shared bond of the indole ring. Our work provides useful insight in designing unnatural proteins having strong ?-stacking interaction between the tryptophan and phenylalanine residues.

Kumar, Sumit; Das, Aloke

2013-09-01

53

High efficiency particulate air filter lives in hydrogen fluoride gas environments.  

National Technical Information Service (NTIS)

Tests of high-efficiency particulate air filters were requested following catastrophic failure of a filter by hydrogen fluoride gas from improper operation in a production line. Operational lives in hydrogen fluoride environments of high-efficiency partic...

J. A. Compton

1992-01-01

54

DEVELOPMENT OF FINE PARTICULATE EMISSION FACTORS AND SPECIATION PROFILES FOR OIL AND GAS-FIRED COMBUSTION SYSTEMS  

SciTech Connect

In 1997, the United States Environmental Protection Agency (EPA) promulgated new National Ambient Air Quality Standards (NAAQS) for particulate matter, including for the first time particles with aerodynamic diameter smaller than 2.5 micrometers ({micro}m) referred to as PM2.5. PM2.5 in the atmosphere also contributes to reduced atmospheric visibility, which is the subject of existing rules for siting emission sources near Class 1 areas and new Regional Haze rules. There are few existing data regarding emissions and characteristics of fine aerosols from oil, gas and power generation industry combustion sources, and the information that is available is generally outdated and incomplete. Traditional stationary source air emission sampling methods tend to underestimate or overestimate the contribution of the source to ambient aerosols because they do not properly account for primary aerosol formation, which occurs after the gases leave the stack. Primary aerosol includes both filterable particles that are solid or liquid aerosols at stack temperature plus those that form as the stack gases cool through mixing and dilution processes in the plume downwind of the source. These deficiencies in the current methods can have significant impacts on regulatory decision-making. PM2.5 measurement issues were extensively reviewed by the American Petroleum Institute (API) (England et al., 1998), and it was concluded that dilution sampling techniques are more appropriate for obtaining a representative particulate matter sample from combustion systems for determining PM2.5 emission rate and chemical speciation. Dilution sampling is intended to collect aerosols including those that condense and/or react to form solid or liquid aerosols as the exhaust plume mixes and cools to near-ambient temperature immediately after the stack discharge. These techniques have been widely used in recent research studies. For example, Hildemann et al. (1994) and McDonald et al. (1998) used filtered ambient air to dilute the stack gas sample followed by 80-90 seconds residence time to allow aerosol formation and growth to stabilize prior to sample collection and analysis. More accurate and complete emissions data generated using the methods developed in this program will enable more accurate source-receptor and source apportionment analysis for PM2.5 National Ambient Air Quality Standards (NAAQS) implementation and streamline the environmental assessment of oil, gas and power production facilities. The overall goals of this program were to: (1) Develop improved dilution sampling technology and test methods for PM2.5 mass emissions and speciation measurements, and compare results obtained with dilution and traditional stationary source sampling methods. (2) Develop emission factors and speciation profiles for emissions of fine particulate matter, especially organic aerosols, for use in source-receptor and source apportionment analyses. (3) Identify and characterize PM2.5 precursor compound emissions that can be used in source-receptor and source apportionment analyses.

Glenn C. England

2004-10-20

55

Partitioning coefficients of polycyclic aromatic hydrocarbons in stack gas from a municipal incinerator  

SciTech Connect

In this study, solid-gas partitioning coefficients of PAHs on fly ash in stack gas from a municipal incinerator were determined according to elution analysis with gas-solid chromatography. The fly ash from the electrostatic precipitator was sieved and packed into a 1/4 inch (6.3 mm) pyrex column. Elution analysis with gas-solid chromatography was conducted for three PAEs, Napthalene, Anthracene, and Pyrene. The temperature for elution analysis was in the range of 100{degrees}C to 300{degrees}C. Vg, specific retention volume obtained from elution analysis, and S, specific surface area of fly ash measured by a surface area measurement instrument were used to estimate the solid-gas partitioning coefficient KR. In addition, the relationships between KR and temperature and KR and PAH concentrations were investigated.

Lee, W.M.G.; Chen, J.C.

1995-12-31

56

A non-sealed solid oxide fuel cell micro-stack with two gas channels  

Microsoft Academic Search

Non-sealed solid oxide fuel cell (NS-SOFC) micro-stacks with two gas channels were fabricated and operated successfully under various CH4\\/O2 gas mixtures in a box-like stainless-steel chamber. The cells with an anode-facing-cathode configuration were connected in serial by zigzag sliver sheets. Each cell consisted of the Ni\\/yttria-stabilized zirconia (YSZ) anode, the YSZ electrolyte, and the Sm0.2Ce0.8O1.9-impregnated (La0.75Sr0.25)0.95MnO3 cathode. In this configuration,

Yanting Tian; Zhe Lü; Bo Wei; Zhihong Wang; Mingliang Liu; Wenyuan Li; Xiqiang Huang; Wenhui Su

2011-01-01

57

Nonwater Quality Impacts of Closed-Cycle Cooling Systems and the Interaction of Stack Gas and Cooling Tower Plumes.  

National Technical Information Service (NTIS)

The report gives results of a literature survey of the nonwater quality impacts of closed-cycle cooling systems. Following discussions of cooling tower and stack gas plumes, interactions of these plumes are considered. For cooling tower plumes, plume type...

G. A. Englesson M. C. Hu

1979-01-01

58

A Review of Electrostatically Augmented Gas Cleaning Devices for Particulate Removal  

Microsoft Academic Search

Increased use of coal as an energy source and strict regulation of environmental emissions have resulted in increased interest in gas stream cleanup. Particulate control is also of great importance for turbine protection in the pressurized fluidized-bed combustion\\/combined cycle (PFBC\\/CC concept for the generation of electricity. Many types of particulate removal devices are commercially available for relatively moderate temperature and

Richard F. Henry; Walter F. Podolski; Satish C. Saxena

1985-01-01

59

Thermal Processing of Particulate Solids in a Gas-Fired Pulse Combustion System  

Microsoft Academic Search

An experimental study on thermal processing of particulate solids has been carried out on a valved pulse combustion unit. The test-bench consists of a 60 kW natural gas-fired valved (flappers) pulse combustor having a 4.63 × 10 m combustion chamber, horizontal tailpipe with variable geometry, and a cylindrical drum. The particulate solid used is clean sand (311 µm and 2646 kg\\/m), which flows within the tailpipe

Marzouk Benali; Robert Legros

2004-01-01

60

Three-dimensional Numerical Simulation of Gas-particulate Flow around Breathing Human and Particulate Inhalation  

NASA Astrophysics Data System (ADS)

It is important to predict the environment around the breathing human because inhalation of virus (avian influenza, SARS) is recently severe worldwide problem, and air pollution caused by diesel emission particle (DEP) and asbestos attract a great deal of attention. In the present study, three-dimensional numerical simulation was carried out to predict unsteady flows around a breathing human and how suspended particulate matter (SPM, diameter~1 ?m) reaches the human nose in inhalation and exhalation. In the calculation, we find out smaller breathing angle and the closer distance between the human nose and pollutant region are effective in the inhalation of SPM.

Shimazaki, Yasuhiro; Okubo, Masaaki; Yamamoto, Toshiaki

2006-05-01

61

Population balance model of heat transfer in gas–solid particulate systems  

Microsoft Academic Search

A population balance model is derived for heat transfer processes in gas–solid systems with intensive motion of particles in order to describe the temperature distribution of particulate phase. The model involves collisional particle–particle and particle–wall heat transfers, and continuous gas–particle, gas–wall and wall–liquid environment heat transfer processes. Collisional heat transfers are characterised by collision frequencies and random heat exchange parameters

B. G. Lakatos; Z. Süle; Cs. Mihálykó

2008-01-01

62

Characterization of polychlorinated naphthalenes in stack gas emissions from waste incinerators.  

PubMed

Nine typical waste incinerating plants were investigated for polychlorinated naphthalene (PCN) contents in their stack gas. The incinerators investigated include those used to incinerate municipal solid, aviation, medical, and hazardous wastes including those encountered in cement kilns. PCNs were qualified and quantified by isotope dilution high resolution gas chromatography-high resolution mass spectrometry techniques. An unexpectedly high concentration of PCNs (13,000 ng Nm(-3)) was found in the stack gas emitted from one waste incinerator. The PCN concentrations ranged from 97.6 to 874 ng Nm(-3) in the other waste incinerators. The PCN profiles were dominated by lower chlorinated homologues, with mono- to tetra-CNs being the main homologues present. Furthermore, the relationships between PCNs and other unintentional persistent organic pollutants involving polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, hexachlorobenzene, and pentachlorobenzene were examined to ascertain the closeness or otherwise of their formation mechanisms. A good correlation was observed between ?PCN (tetra- to octa-CN) and ?PCDF (tetra- to octa-CDF) concentrations suggesting that a close relationship may exist between their formation mechanisms. The results would provide an improved understanding of PCN emissions from waste incinerators. PMID:23054784

Hu, Jicheng; Zheng, Minghui; Liu, Wenbin; Li, Changliang; Nie, Zhiqiang; Liu, Guorui; Zhang, Bing; Xiao, Ke; Gao, Lirong

2012-09-29

63

Assessment of the Losses Due to Self Absorption by Mass Loading on Radioactive Particulate Air Stack Sample Filters  

SciTech Connect

This report discusses the effect of mass loading of a membrane filter on the self absorption of radioactive particles. A relationship between mass loading and percent loss of activity is presented. Sample filters were collected from Pacific Northwest National Laboratory (PNNL) facilities in order to analyze the current self absorption correction factor of 0.85 that is being used for both alpha and beta particles. Over an eighteen month period from February 2009 to July 2010, 116 samples were collected and analyzed from eight different building stacks in an effort coordinated by the Effluent Management group. Eleven unused filters were also randomly chosen to be analyzed in order to determine background radiation. All of these samples were collected and analyzed in order to evaluate the current correction factor being used.

Smith, Brian M.; Barnett, J. M.; Ballinger, Marcel Y.

2011-01-18

64

Comparison of the electric charging properties of particulate materials in gas–solids flows in pipelines  

Microsoft Academic Search

The charging trends of particulate materials in gas–solid flows in pipelines are of considerable interest to designers of such flow systems, particularly with regard to flow instruments based on electrostatic measurement principles. Such data may also be useful to other researchers in associated fields. The authors of this paper, therefore, set about obtaining such data empirically. In order to achieve

D. I. Armour-Chélu; S. R. Woodhead

2002-01-01

65

Students' Conceptual Representations of Gas Volume in Relation to Particulate Model of Matter.  

ERIC Educational Resources Information Center

|Most high school chemistry curricula contain a unit on gas volume and a unit on the particulate nature of matter. The existence and persistence of adolescent preconceptions about the material nature of gases is an important factor to be considered in the teaching of principles or theories related to gases. The purpose of the study reported in…

Hwang, Bao-tyan

66

NOVEL CONCEPTS, METHODS AND ADVANCED TECHNOLOGY IN PARTICULATE/GAS SEPARATION  

EPA Science Inventory

This paper discusses presentations made during a symposium on novel concepts, methods, and advanced technology in particulate/gas separation. The symposium, held at the University of Notre Dame and sponsored by the National Science Foundation and the Environmental Protection Agen...

67

Efficient particulate scrubber for glass melter off-gas  

SciTech Connect

Operation of joule-heated, continuous slurry fed melters has demonstrated that off-gas aerosols are generated by entrainment of feed slurry and vaporization of volatile species from the melt. Effective off-gas stream decontamination for these aerosols can be obtained by utilizing a suitably designed and operated wet scrubber system. Results are presented for performance tests conducted with an air aspirating-type venturi scrubber processing a simulated melter off-gas aerosol. Mass removal efficiencies ranged from 99.5 to 99.8%. Details of the testing program and applications for melter off-gas system design are discussed.

Wright, G.T.

1982-01-01

68

Efficient particulate scrubber for glass melter off-gas  

SciTech Connect

Operation of joule-heated, continuous slurry-fed melters has demonstrated that off-gas aerosols are generated by entrainment of feed slurry and vaporization of volatile species from the melt. Effective off-gas stream decontamination for these aerosols can be obtained by utilizing a suitably designed and operated wet scrubber system. Results are presented for performance tests conducted with an air aspirating-type venturi scrubber processing a simulated melter off-gas aerosol. Mass overall removal efficiencies ranged from 99.5 to 99.8%. Details of the testing program and applications for melter off-gas system design are discussed.

Wright, G.T.

1983-01-01

69

Identifying and controlling WTE (waste-to-energy) stack emissions  

Microsoft Academic Search

This article focuses on stack emissions from large, mass burn WTE plants equipped with acid gas and high efficiency particulate controls. Several dozen mass burn plants are operating or in the planning, design, and construction stages in the US. The emission data in this article come from plants that began operation in the 1980s. Optimal furnace operation and emissions control

R. Li; P. W. Frillici; J. W. Wilson

1990-01-01

70

Numerical Simulation of CO and NO Emissions during Converter Off-Gas Combustion in the Cooling Stack  

Microsoft Academic Search

Oxygen converter steelmaking produces a large amount of high temperature off-gas. During pre- and post-combustion of converter off-gas in the cooling stack, CO concentration at outlet is always over emission standard, and NO emission is still paid little attention. In the paper, CO and NO emissions are investigated during converter off-gas combustion by CFD. The simulation results indicate that CO

Sen Li; Xiaolin Wei

2012-01-01

71

Gas and Particulate Sampling of Airborne Polycyclic Aromatic Compounds  

SciTech Connect

The denuder surfaces of the gas and particle (GAP) sampler (developed at the Atmospheric Environment Service of Environment Canada) have been modified by coating with XAD-4 resin, using techniques developed at Lawrence Berkeley National Laboratory (LBNL) for the lower capacity integrated organic vapor/particle sampler (IOVPS). The resulting high capacity integrated organic gas and particle sampler (IOGAPS) has been operated in ambient air at 16.7 L min{sup -1} for a 24-hour period in Berkeley, California, USA. Simultaneous measurements were made at the same collection rate with a conventional sampler that used a filter followed by two sorbent beds. Gas and particle partition measurements were determined for 13 polycyclic aromatic hydrocarbons (PAH) ranging from 2-ring to 6-ring species. The IOGAPS indicated a higher particle fraction of these compounds than did the conventional sampler, suggesting that the conventional sampler suffered from 'blow-off' losses from the particles collected on the filter.

Lane, D.A.; Gundel, L.A.

1995-10-01

72

A particulate basis for an immiscible lattice-gas model  

NASA Astrophysics Data System (ADS)

We show that a phenomenological hydrodynamic lattice-gas model of two-phase flow, developed by Rothman and Keller in 1988 and used extensively for numerical simulations since then, can be derived from an underlying model of particle interactions. From this result, we elucidate the nature of the hydrodynamic limit of the Rothman-Keller model.

Boghosian, Bruce M.; Coveney, Peter V.

2000-07-01

73

NONWATER QUALITY IMPACTS OF CLOSED-CYCLE COOLING SYSTEMS AND THE INTERACTION OF STACK GAS AND COOLING TOWER PLUMES  

EPA Science Inventory

The report gives results of a literature survey of the nonwater quality impacts of closed-cycle cooling systems. Following discussions of cooling tower and stack gas plumes, interactions of these plumes are considered. For cooling tower plumes, plume types, behavior, salt drift g...

74

Comparison of Different Gas-Phase Mechanisms and Aerosol Modules for Simulating Particulate Matter Formation  

Microsoft Academic Search

The effects of two gas-phase chemical kinetic mechanisms, Regional Atmospheric Chemistry Mechanism version 2 (RACM2) and Carbon-Bond 05 (CB05), and two secondary organic aerosol (SOA) modules, the Secondary Organic Aerosoi Model (SORGAM) and AER\\/EPRI\\/Caltech model (AEC), on fine (aerodynamic diameter ?2.5 ?m) particulate matter (PM2.5) formation is studied. The major sources of uncertainty in the chemistry of SOA formation are

Youngseob Kim; Florian Couvidat; Karine Sartelet; Christian Seigneur

2011-01-01

75

Confined vortex scrubber offers high-efficiency acid gas and particulate removal  

SciTech Connect

Over the years, proponents of the defense industry have maintained that many of the technologies developed for the military can be successfully adapted to civilian applications. One example of such technology transfer could be the use of confined vortex scrubbers for emission control applications. Originally developed during research into nuclear rocket propulsion, these devices use the force generated by rotational gas flow to hold introduced liquid in a stable vortex. The resulting contact between gas and liquid phases removes acid gases and particulate matter from combustion process offgases. The use of a confined vortex scrubber for emission control is described in this paper. 1 ref., 2 figs.

NONE

1995-05-01

76

The Lockman Hole project: gas and galaxy properties from a stacking experiment  

NASA Astrophysics Data System (ADS)

We perform an H I stacking analysis to study the relation between H I content and optical/radio/IR properties of galaxies located in the Lockman Hole area. In the redshift range covered by the observations (up to z = 0.09), we use the SDSS to separate galaxies with different optical characteristics, and we exploit the deep L-band radio continuum image (with noise 11 ?Jy beam-1) to identify galaxies with radio continuum emission. Infrared properties are extracted from the Spitzer catalog. We detect H I in blue galaxies, but H I is also detected in the group of red galaxies - albeit with smaller amounts than for the blue sample. We identify a group of optically inactive galaxies with early-type morphology that does not reveal any H I and ionized gas. These inactive galaxies likely represent the genuine red and dead galaxies depleted of all gas. Unlike inactive galaxies, H I is detected in red LINER-like objects. Galaxies with radio continuum counterparts mostly belong to the sub-mJy population, whose objects are thought to be a mixture of star-forming galaxies and low-power AGNs. After using several AGN diagnostics, we conclude that the radio emission in the majority of our sub-mJy radio sources stems from star formation. LINERs appear to separate into two groups based on IR properties and H I content. LINERs with a 24 ?m detection show relatively large amounts of H I and are also often detected in radio continuum as a result of ongoing star formation. The LINER galaxies which are not detected at 24 ?m are more like the optically inactive galaxies by being depleted of H I gas and having no sign of star formation. Radio LINERs in the latter group are the best candidates for hosting low-luminosity radio AGN.

Geréb, K.; Morganti, R.; Oosterloo, T. A.; Guglielmino, G.; Prandoni, I.

2013-10-01

77

Estimating the human health risks from polychlorinated dioxins and furans in stack gas emissions from combustion units: implications of USEPA's dioxin reassessment  

Microsoft Academic Search

Shortly after promulgation of the Hazardous Waste Combustor MACT rule established regulatory limits for polychlorinated dioxins and furans (dioxins\\/furans) in incinerator stack gas, the US Environmental Protection Agency (USEPA) announced that facilities could still be required to demonstrate that stack emissions do not present an unacceptable risk to human health and the environment. Guidance for conducting this risk assessment activity,

John U. Bell

2002-01-01

78

Inadequacy of Optical Smoke Measurements for Characterisation of Non-Light Absorbing Particulate Matter Emissions From Gas Turbine Engines  

Microsoft Academic Search

Analysis of Particulate Matter (PM) emissions from gas turbine engines, using the conventional Smoke Number (SN) technique provides a measure of plume visibility. In this study, PM emissions were sampled from the exhaust of a small gas turbine engine, burning Jet A-1 and Biodiesel. SN results indicated that Biodiesel significantly reduced visible emissions. Analysis of PM number and mass concentrations

L. Rye; P. Lobo; P. I. Williams; I. Uryga-Bugajska; S. Christie; C. Wilson; D. Hagen; P. Whitefield; S. Blakey; H. Coe; D. Raper; M Pourkashanian

2012-01-01

79

Mobile Gas and Particulate Emission Studies of the New York City Transit Bus Fleet  

NASA Astrophysics Data System (ADS)

Emissions from both diesel and gasoline powered motor vehicles are a significant source of particulate (PM2.5) and trace gas pollution, especially in urban environments. Emission characterizations of motor vehicles can be performed using a dynamometer but these studies make fleet characterization impractical. Few studies have been performed which characterize emissions from in-use vehicles using a mobile sampling platform. This work describes application of new technology instrumentation for rapid (1-5 second) and real-time characterization of both gas and particulate emissions from in-use vehicles and is part of the PM2.5 Technology Assessment and Characterization Study in New York (PMTACS-NY). An aerosol mass spectrometer (AMS) and a tunable infrared laser differential absorption spectrometer (TILDAS) system were deployed on the Aerodyne Research mobile laboratory designed to "chase" target vehicles in and around the New York City area and measure their emissions under actual driving conditions. The AMS provides particle size and composition information for volatile and semi-volatile matter while the TILDAS system was configured to measure NO, NO2, CO, CH4, SO2 and formaldehyde. In addition to a GPS, an ELPI and a condensation particle counter, the mobile laboratory was also equipped with a CO2 monitor to allow emission ratios to be computed for the targeted vehicles. Emission ratios for both particulate and trace gases are reported for a representative fraction of the NYC Metropolitan Transit Authority (MTA) bus fleet in an effort to characterize new emission control technologies currently implemented by the NYC MTA.

Jayne, J. T.; Canagaratna, M.; Herndon, S.; Shorter, J.; Zahniser, M.; Shi, Q.; Kolb, C.; Worsnop, D.; Jimenez, J.; Drewnick, F.; Demerjian, K.; Lanni, T.

2001-12-01

80

Separation of particulate from flue gas of fossil fuel combustion and gasification  

DOEpatents

The gas from combustion or gasification of fossil fuel contains flyash and other particulate. The flyash is separated from the gas in a plurality of standleg moving granular-bed filter modules. Each module includes a dipleg through which the bed media flows into the standleg. The bed media forms a first filter bed having an upper mass having a first frusto-conical surface in a frusto-conical member at the entrance to the standleg and a lower mass having a second frusto-conical surface of substantially greater area than the first surface after it passes through the standleg. A second filter media bed may be formed above the first filter media bed. The gas is fed tangentially into the module above the first surface. The flyash is captured on the first frusto-conical surface and within the bed mass. The processed gas flows out through the second frusto-conical surface and then through the second filter bed, if present. The bed media is cleaned of the captured flyash and recirculated to the moving granular bed filter. Alternatively, the bed media may be composed of the ash from the combustion which is pelletized to form agglomerates. The ash flows through the bed only once; it is not recycled.

Yang, Wen-Ching (Murrysville, PA); Newby, Richard A. (Pittsburgh, PA); Lippert, Thomas E. (Murrysville, PA)

1997-01-01

81

Separation of particulate from flue gas of fossil fuel combustion and gasification  

DOEpatents

The gas from combustion or gasification of fossil fuel contains fly ash and other particulates. The fly ash is separated from the gas in a plurality of standleg moving granular-bed filter modules. Each module includes a dipleg through which the bed media flows into the standleg. The bed media forms a first filter bed having an upper mass having a first frusto-conical surface in a frusto-conical member at the entrance to the standleg and a lower mass having a second frusto-conical surface of substantially greater area than the first surface after it passes through the standleg. A second filter media bed may be formed above the first filter media bed. The gas is fed tangentially into the module above the first surface. The fly ash is captured on the first frusto-conical surface and within the bed mass. The processed gas flows out through the second frusto-conical surface and then through the second filter bed, if present. The bed media is cleaned of the captured fly ash and recirculated to the moving granular bed filter. Alternatively, the bed media may be composed of the ash from the combustion which is pelletized to form agglomerates. The ash flows through the bed only once; it is not recycled. 11 figs.

Yang, W.C.; Newby, R.A.; Lippert, T.E.

1997-08-05

82

Real-Time Characterization of Particle and Gas Phase Diesel Emissions - Understanding the Influence of a Diesel Particulate Filter  

Microsoft Academic Search

Diesel engine emissions constitute an important source of particulate black carbon (BC) and gas phase organics in the atmosphere. Particles composed of black carbon absorb incoming solar radiation having a net positive radiative forcing effect on the climate. Black carbon also has major air quality implications as BC particles from combustion sources are often coated with poly-aromatic hydrocarbons (PAHs), and

E. S. Cross; A. Sappok; A. J. Carrasquillo; T. B. Onasch; E. Fortner; J. Jayne; V. Wong; D. R. Worsnop; J. H. Kroll

2010-01-01

83

Composition, Toxicity, and Mutagenicity of Particulate and Semivolatile Emissions from Heavy-Duty Compressed Natural Gas-Powered Vehicles  

Microsoft Academic Search

Particulate matter (PM) and vapor-phase semivolatile organic compounds (SVOC) were collected from three buses fueled by com- pressed natural gas. The bus engines included a well-functioning, conventional engine; a ''high emitter'' engine; and a new technol- ogy engine with an oxidation catalyst. Chemical analysis of the emissions showed differences among these samples, with the high emitter sample containing markers of

JeanClare Seagrave; Andrew Gigliotti; Jacob D. McDonald; Steven K. Seilkop; Kevin A. Whitney; Barbara Zielinska; Joe L. Mauderly

2005-01-01

84

SIZE DISTRIBUTIONS OF TRACE METALS IN FLUE GAS PARTICULATE FROM A PILOT-SCALE ROTARY KILN INCINERATOR  

EPA Science Inventory

The distributions of nine trace metals in flue gas particulate by particle size range were determined as part of a pilot-scale hazardous waste incineration test program. hese tests were conducted in the rotary kiln incinerator system at the U.S. EPA's Incineration Research Facili...

85

40 CFR 86.109-94 - Exhaust gas sampling system; Otto-cycle vehicles not requiring particulate emission measurements.  

Code of Federal Regulations, 2013 CFR

...Exhaust gas sampling system; Otto-cycle vehicles not requiring particulate emission measurements...EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1977 and Later Model Year New Light-Duty Vehicles and New Light-Duty Trucks and New...

2013-07-01

86

Gas?particulate phase distribution and decay rates of constituents in ageing environmental tobacco smoke  

Microsoft Academic Search

Phase distribution and decay rates of ETS components were determined for an experimental room. Solanesol and protonated nicotine behave like particulate matter (UV?PM). Free nicotine evaporates from the particulate phase during the 5 minute sampling time and decays rapidly from the gaseous phase. Neophytadiene leaves the particulate phase faster than predicted by deposition. Limonene, 3?ethenylpyridine, and naphthalene are present only

Georg B. Neurath; Sylvia Petersen; Michael Dunger; Dorothea Orth; F. Gerhard Pein

1991-01-01

87

METHODS AND RESULTS OF RECONSTRUCTION OF NOBLE GAS RELEASES FROM THE STACKS OF THE MAYAK PA GRAPHITE REACTORS OVER THE WHOLE PERIOD OF THEIR OPERATION  

SciTech Connect

Brief analysis of design features and operational modes of Mayak PA industrial graphite-uranium reactors (PUGRs) is given. The above mentioned Mayak PA PUGRs determined the rates of releases of radioactive noble gases (RNG) from activation (41Ar) and fission (isotopes of Krypton and Xenon) through the vent stack of the reactor. Information is given on methods and results of experimental determination of RNG atmospheric releases for the period starting from 1965 till PUGRs decommissioning in 1987-1990. A calculation method for reconstruction of radioactive noble gas releases is proposed and justified. The results of reconstruction are given. It is shown that maximum rates of RNG releases from PUGRs high stacks were observed in the 1950s, when ordinary atmospheric air was used as a cover gas for the reactor graphite stacks and gas purification systems (flow-type gas holders) had not been installed yet.

Glagolenko, Y. V.; Drozhko, Evgeniy G.; Mokrov, Y.; Pyatin, N. P.; Rovny, Sergey I.; Anspaugh, L. R.; Napier, Bruce A.

2008-06-01

88

Operating characteristics of a 5 kW class anode-supported planar SOFC stack for a fuel cell\\/gas turbine hybrid system  

Microsoft Academic Search

We designed and constructed a pressurized 5kW anode-supported planar solid oxide fuel cell (SOFC) power generation system with a pre-reformer for a fuel cell\\/gas turbine hybrid system. The 5kW class SOFC stack, which was made by Forschungszentrum Jülich (FZJ) in Germany, was assembled and installed at KIER. We also investigated the stack's typical operating characteristics, particularly with respect to the

Tak-Hyoung Lim; Rak-Hyun Song; Dong-Ryul Shin; Jung-Il Yang; Heon Jung; I. C. Vinke; Soo-Seok Yang

2008-01-01

89

Post-test analysis of 20kW molten carbonate fuel cell stack operated on coal gas. Final report, August 1993--February 1996  

SciTech Connect

A 20kW carbonate fuel cell stack was operated with coal gas for the first time in the world. The stack was tested for a total of 4,000 hours, of which 3,900 hours of testing was conducted at the Louisiana Gasification Technology Incorporated, Plaquemine, Louisiana outdoor site. The operation was on either natural gas or coal gas and switched several times without any effects, demonstrating duel fuel capabilities. This test was conducted with 9142 kJ/m{sup 3} (245 Btu/cft) coal gas provided by a slipstream from Destec`s entrained flow, slagging, slurry-fed gasifier equipped with a cold gas cleanup subsystem. The stack generated up to 21 kW with this coal gas. Following completion of this test, the stack was brought to Energy Research Corporation (ERC) and a detailed post-test analysis was conducted to identify any effects of coal gas on cell components. This investigation has shown that the direct fuel cell (DFC) can be operated with properly cleaned and humidified coal-as, providing stable performance. The basic C direct fuel cell component materials are stable and display normal stability in presence of the coal gas. No effects of the coal-borne contaminants are apparent. Further cell testing at ERC 1 17, confirmed these findings.

NONE

1996-05-01

90

Sampling of power plant stacks for air toxic emissions: Topical report for Phases 1 and 2  

SciTech Connect

Under contract with the US Department of Energy (DE-AC22-92PCO0367), Pittsburgh Energy Technology Center, Radian Corporation has conducted a test program to collect and analyze size-fractionated stack gas particulate samples for selected inorganic hazardous air pollutants (HAPS). Specific goals of the program are (1) the collection of one-gram quantities of size-fractionated stack gas particulate matter for bulk (total) and surface chemical charactization, and (2) the determination of the relationship between particle size, bulk and surface (leachable) composition, and unit load. The information obtained from this program identifies the effects of unit load, particle size, and wet FGD system operation on the relative toxicological effects of exposure to particulate emissions.

NONE

1995-02-21

91

Modular fuel-cell stack assembly  

DOEpatents

A modular multi-stack fuel-cell assembly in which the fuel-cell stacks are situated within a containment structure and in which a gas distributor is provided in the structure and distributes received fuel and oxidant gases to the stacks and receives exhausted fuel and oxidant gas from the stacks so as to realize a desired gas flow distribution and gas pressure differential through the stacks. The gas distributor is centrally and symmetrically arranged relative to the stacks so that it itself promotes realization of the desired gas flow distribution and pressure differential.

Patel, Pinakin (Danbury, CT); Urko, Willam (West Granby, CT)

2008-01-29

92

STUDY ON THE FEASIBILITY AND DESIGN OF AUTOMATIC PARTICULATE SIZE DISTRIBUTION ANALYZER FOR SOURCE EMISSIONS  

EPA Science Inventory

The objective of this program was to evolve a method for the automatic determination of the size distribution of particulates within stack gas effluent streams. This device was designed to cover the typical mass concentration range encountered upstream as well as downstream of em...

93

40 CFR 86.1320-90 - Gas meter or flow instrumentation calibration; particulate, methanol, and formaldehyde measurement.  

Code of Federal Regulations, 2010 CFR

...instrumentation calibration; particulate, methanol, and formaldehyde measurement...instrumentation calibration; particulate, methanol, and formaldehyde measurement. (a) Sampling for particulate, methanol and formaldehyde emissions...

2009-07-01

94

40 CFR 86.120-94 - Gas meter or flow instrumentation calibration; particulate, methanol and formaldehyde measurement.  

Code of Federal Regulations, 2010 CFR

...instrumentation calibration; particulate, methanol and formaldehyde measurement. 86...instrumentation calibration; particulate, methanol and formaldehyde measurement. (a) Sampling for particulate, methanol and formaldehyde emissions...

2009-07-01

95

40 CFR 86.1320-90 - Gas meter or flow instrumentation calibration; particulate, methanol, and formaldehyde measurement.  

Code of Federal Regulations, 2010 CFR

...instrumentation calibration; particulate, methanol, and formaldehyde measurement...instrumentation calibration; particulate, methanol, and formaldehyde measurement. (a) Sampling for particulate, methanol and formaldehyde emissions...

2010-07-01

96

40 CFR 86.120-94 - Gas meter or flow instrumentation calibration; particulate, methanol and formaldehyde measurement.  

Code of Federal Regulations, 2010 CFR

...instrumentation calibration; particulate, methanol and formaldehyde measurement. 86...instrumentation calibration; particulate, methanol and formaldehyde measurement. (a) Sampling for particulate, methanol and formaldehyde emissions...

2010-07-01

97

Including impacts of particulate emissions on marine ecosystems in life cycle assessment: the case of offshore oil and gas production.  

PubMed

Life cycle assessment is increasingly used to assess the environmental performance of fossil energy systems. Two of the dominant emissions of offshore oil and gas production to the marine environment are the discharge of produced water and drilling waste. Although environmental impacts of produced water are predominantly due to chemical stressors, a major concern regarding drilling waste discharge is the potential physical impact due to particles. At present, impact indicators for particulate emissions are not yet available in life cycle assessment. Here, we develop characterization factors for 2 distinct impacts of particulate emissions: an increased turbidity zone in the water column and physical burial of benthic communities. The characterization factor for turbidity is developed analogous to characterization factors for toxic impacts, and ranges from 1.4 PAF (potentially affected fraction) · m(3) /d/kg(p) (kilogram particulate) to 7.0 x 10³ [corrected] for drilling mud particles discharged from the rig. The characterization factor for burial describes the volume of sediment that is impacted by particle deposition on the seafloor and equals 2.0 × 10(-1) PAF · m(3) /d/kg(p) for cutting particles. This characterization factor is quantified on the basis of initial deposition layer characteristics, such as height and surface area, the initial benthic response, and the recovery rate. We assessed the relevance of including particulate emissions in an impact assessment of offshore oil and gas production. Accordingly, the total impact on the water column and on the sediment was quantified based on emission data of produced water and drilling waste for all oil and gas fields on the Norwegian continental shelf in 2008. Our results show that cutting particles contribute substantially to the total impact of offshore oil and gas production on marine sediments, with a relative contribution of 55% and 31% on the regional and global scale, respectively. In contrast, the contribution of particulate emissions to the total impact on the marine water column is of minor importance. We conclude that particles are an important stressor in marine ecosystems, particularly for marine sediment, and particulate emissions should therefore be included in a (life cycle) impact assessment of offshore oil and gas production. PMID:21735543

Veltman, Karin; Huijbregts, Mark A J; Rye, Henrik; Hertwich, Edgar G

2011-08-26

98

Stacked Regressions  

Microsoft Academic Search

Stacking regressions is a method for forming linear combinations of different predictors to give improved prediction accuracy. The idea is to use cross-validation data and least squares under non-negativity constraints to determine the coefficients in the combination. Its effectiveness is demonstrated in stacking regression trees of different sizes and in a simulation stacking linear subset and ridge regressions. Reasons why

Leo Breiman; Ross Quinlan

1996-01-01

99

Stacked Regressions  

Microsoft Academic Search

Stacking regressions is a method for forming linear combinations of different predictors to give improved prediction accuracy. The idea is to use cross-validation data and least squares under non negativity constraints to determine the coefficients in the combination. Its effectiveness is demonstrated in stacking regression trees of different sizes and in a simulation stacking linear subset and ridge regressions. Reasons

Leo Breiman

1996-01-01

100

40 CFR 86.110-94 - Exhaust gas sampling system; diesel-cycle vehicles, and Otto-cycle vehicles requiring particulate...  

Code of Federal Regulations, 2013 CFR

... Exhaust gas sampling system; diesel-cycle vehicles, and Otto-cycle vehicles requiring particulate emissions measurements...CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1977...

2013-07-01

101

Greenhouse Gas and Particulate Emissions and Impacts from Cooking Technologies in Africa  

NASA Astrophysics Data System (ADS)

In much of Africa, the largest fraction of energy consumption occurs within the residential sector and is derived primarily from woodfuels burned in simple stoves with poor combustion characteristics. Many of the products of incomplete combustion (PICs) are damaging to human health, particularly when they are concentrated in poorly ventilated indoor environments. Incomplete combustion also has potentially harmful impacts on the climate. Prevalent PICs include methane, a potent greenhouse gas (GHG) that is among the pollutants subject to controls under the Kyoto Protocol as well as carbon monoxide (CO), non-methane hydrocarbons (NMHCs) and particulate matter (PM), which can all have an effect on climate, but are not subject to controls under Kyoto. In addition, when woodfuels are used at a rate that reduces standing stocks of trees over the medium or long term, the CO2 released by combustion also has an impact. The choice of stove and fuel technology can have a significant impact on the emission of GHGs as well as on human exposure to health damaging pollutants. In this paper we analyze the emissions of different household energy technologies on a life-cycle basis. We use emission factors to estimate the emissions associated with production, distribution and end-use of common household fuels and assess the likely impacts of these emissions on public health and the global environment. We focus largely on charcoal, a popular fuel in many sub-Saharan African countries. Charcoal is produced by heating wood in the absence of sufficient air for complete combustion to occur. This process removes moisture and most of the volatile compounds. The compounds driven off in the process consist of condensable tars as well as many gaseous hydrocarbons, including ~40 g CH4 per kg of charcoal produced. Combining upstream and end-use emissions, every meal cooked with charcoal has 2-10 times the global warming effect of cooking the same meal with firewood and 5-12 times the effect of cooking the same meal with LPG or kerosene. When charcoal is produced in large quantities, as it is in Africa, the net warming effect can exceed the impact from the "modern energy sector" (transportation and industry) by 50-100 percent, even if charcoal is produced on a sustainable cycle so that all of the wood harvested for charcoal production is allowed to regenerate. However, while charcoal may be worse than firewood with respect to greenhouse gas emissions, it is an improvement with respect to exposure to health damaging pollutants, particularly particulate matter (PM). Levels of PM in households using charcoal are over 90 percent lower than households using open wood fires (316 -(159) mg/m3 for households using charcoal in a common improved stove compared to 3764 (360) mg/m3) for households using wood in open fires: mean (standard error)). These differences in exposure are consistent with 30 and 50 percent reductions in the incidence of acute respiratory infection (ARI) in adults and children under 5 respectively. Reconciling the costs and benefits of different household energy technologies creates a difficult policy challenge, particularly with the severe budgetary and resource constraints that household consumers and government agencies face in sub-Saharan Africa.

Kammen, D. M.; Bailis, R.; Kituyi, E.; Ezzati, M.

2003-12-01

102

Stacked generalization  

Microsoft Academic Search

: This paper introduces stacked generalization, a scheme for minimizing the generalizationerror rate of one or more generalizers. Stacked generalization works by deducing the biases of thegeneralizer(s) with respect to a provided learning set. This deduction proceeds by generalizing ina second space whose inputs are (for example) the guesses of the original generalizers when taughtwith part of the learning set

David H. Wolpert

1992-01-01

103

Study Stack  

NSDL National Science Digital Library

Developed by John Weidner, the Study Stack concept basically assists individuals to memorize information about various subjects, including geography, history, math, languages, and science. Users of the site can select one of the existing stacks, which consists of virtual study cards allowing individuals to learn at their own pace until they are satisfied with their progress. What is also particularly novel about this learning tool is that data entered for customized study stacks can be automatically displayed as a matching game, a word search puzzle, or a hangman game. So far, the site contains dozens of study stacks for each subject, with the areas dedicated to math and science containing quite a number of rather helpful stacks. With its wide range of applications, this site will be very helpful to students at different age levels and teachers who may be seeking to develop a new study tool for any number of topics or themes within a subject area.

Weidner, John

104

Impacts of Gas-phase Chemical Mechanisms on Modeled Responses of Ozone and Fine Particulate Matter to Emission Changes  

NASA Astrophysics Data System (ADS)

Two air pollutants of most concern are ozone and fine particulate matter (i.e., PM2.5; particulate matter with an aerodynamic diameter less than 2.5 ?m) due to their adverse human health effects. Gas-phase chemical mechanisms are one of the important components in regional air quality models and applied to describe the formation of air pollutants such as ozone and secondary PM2.5. Modeled responses of air pollutant concentrations to precursor emission changes (i.e., sensitivities) provide useful information for developing air pollution mitigation strategies and are expected to be affected by gas-phase chemical mechanisms chosen for air quality simulations. The goal of this study is to investigate impacts of gas-phase chemical mechanisms on modeled responses of ozone and PM2.5 concentrations to emission reductions over the eastern United States. We used the U.S. Environmental Protection Agency's regional air quality model, Community Multiscale Air Quality Model (CMAQ) version 4.7.1, to simulate three-dimensional gridded concentrations of ambient ozone, PM2.5 and other air pollutants during three summer months (June, July and August) in 2007. A uniform grid of 12 by 12 km horizontal cells with 34 vertical layers was employed in the air quality simulations. Two gas-phase chemical mechanisms (CB-05; Carbon Bond Mechanism, version V and SAPRC-99; Statewide Air Pollution Research Center, version 99) were used in the regional air quality simulations. The preliminary results show that modeled responses of peak ozone levels to emission changes could be affected by the gas-phase chemical mechanism chosen in air quality modeling. The effects of gas-phase chemical mechanisms on modeled responses of PM2.5 to emission changes are small. Final results of this modeling study and related discussion will be presented at the conference.

Liao, Kuo-Jen

2013-04-01

105

Compound Specific Concentration and Stable Isotope Ratio Measurements of Atmospheric Particulate Organic Matter and Gas Phase Nitrophenols  

NASA Astrophysics Data System (ADS)

Atmospheric particulate organic matter (POM) adversely affects health and climate. One of the still poorly understood sources of secondary organic matter (SOM) is the formation of secondary POM from the photo- oxidation of atmospheric volatile organic compounds (VOC). Nitrophenols, which are toxic semi-volatile compounds, are formed in the atmosphere by OH-radical initiated photo-oxidation of aromatic hydrocarbons, such as toluene. A method was developed to determine concentrations and stable carbon isotope ratios of particulate methyl nitrophenols in the atmosphere. This method has been used to quantify methyl nitrophenols, specifically 2-methyl-4-nitrophenol and 4-methyl-2-nitrophenol, found in atmospheric PM samples in trace quantities. Using this method, we conducted measurements of methyl nitrophenols in atmospheric PM in rural and suburban areas in Southern Ontario. The results of these measurements showed that the concentration of methyl nitrophenols in atmospheric PM is much lower than expected from the extrapolation of laboratory experiments and measured atmospheric toluene concentrations. In order to better understand the reasons for these findings, an analytical method for the analysis of nitrophenols in the gas phase is currently being developed. Similarly, the measurement technique is modified to allow analysis of other phenolic products of the oxidation of aromatic hydrocarbons in PM as well as in the gas phase. In this poster, sampling techniques for collection and GC-MS analysis of nitrophenols in gas phase and PM will be presented along with preliminary results from summer 2008 and spring 2009 studies.

Busca, R.; Saccon, M.; Moukhtar, S.; Rudolph, J.

2009-05-01

106

Understanding the effect of reformate gas components and stack component impurities on the performance of PEM fuel cells  

NASA Astrophysics Data System (ADS)

The performance can be lost depending on the concentration and type of reformate components. Gas crossover in PEMFCs can also cause performance loss and these effects are also presented. Impurities such as acetone coming from composite stack components and sealants can also deteriorate the performance severely. Electrochemical impedance spectroscopy (EIS) is used as a diagnostic tool to study the impurity poisoning. Reformate contains N2 and CO2 and these components affect performance differently. These effects were quantified using anode overvoltage. Data for anode overvoltage shows that CO2 yields a significant poisoning effect (about 30 mV) on a Pt electrode. Cyclic voltammetry (CV) data showed that CO was produced in-situ from CO2 and H 2 (reverse water gas shift (RWGS) reaction) on both Pt and Pt/Ru electrodes. The coverage of CO achieved by RWGS can reach 5 x 10-7 mol/cm2 on an electrode with 0.4 mg/cm2 Pt under open circuit with normal operating conditions. This work also investigated how pressure, gas composition, and temperature affect the RWGS reaction in a PEMFC for both Pt and Pt/Ru alloy catalysts. The data are shown to be consistent with a kinetic catalytic model and not with an equilibrium model. Data was presented on H2 and O2 crossover in PEMFCs. Electrochemical techniques and mass balance measurements were used to quantify the crossover under typical working conditions. Mixed potential theory was applied to analyze the effect of gas crossover on open circuit voltage (OCV) of PEMFCs. Off-gassing from bipolar plates previously identified styrene, acetone, t-butyl alcohol, and dimethyl succinate as impurities. The effects of those impurities were quantified with both poisoning-recovery transient curves and steady state VI curves before, during, and after poisoning on anode and cathode side respectively. The poisoning effects of them to the anode side are smaller than to the cathode side. Cyclic voltammetry and electrochemical impedance spectroscopy were used to analyze the poisoning mechanisms of the above species. CV data showed that these organic species can be oxidized at about 0.6 V (vs. dynamic hydrogen electrode (DHE)) on a Pt electrode. Analysis of EIS data suggests that when these impurities were applied to the anode side, they deteriorated the cell performance by crossing over to the cathode side and increased the cathode resistances.

Gu, Tao

107

Flue gas conditioning for reducing suspended particulate matter from thermal power stations  

Microsoft Academic Search

Increased population and industrial development demands sustainable electricity, the majority of which is produced by thermal power stations, which utilize coal as a fuel all over the world. Coal burning results in generation of large quantities of coal residues, which contains very fine particles that tend to become air-borne and which contribute to the formation of suspended particulate matter (SPM).

S. Shanthakumar; D. N. Singh; R. C. Phadke

2008-01-01

108

Fuel cell stack compressive loading system  

DOEpatents

A fuel cell module comprising a stack of fuel cells with reactant gas manifolds sealed against the external surfaces of the stack includes a constraint system for providing a compressive load on the stack wherein the constraint system maintains the stack at a constant height (after thermal expansion) and allows the compressive load to decrease with time as a result of the creep characteristics of the stack. Relative motion between the manifold sealing edges and the stack surface is virtually eliminated by this constraint system; however it can only be used with a stack having considerable resiliency and appropriate thermal expansion and creep characteristics.

Fahle, Ronald W. (Manchester, CT); Reiser, Carl A. (Glastonbury, CT)

1982-01-01

109

On Stacking  

NASA Astrophysics Data System (ADS)

The term 'stacking' is normally associated with ? - ? interactions between aromatic moieties. The parallel alignment between adjacent DNA bases arguably constitutes the best-known example and provides the dominating contribution to the overall stability of DNA duplexes. Beyond canonical ? - ? interactions, a preliminary inspection of crystal structures of nucleic acids and their complexes with proteins reveals a wealth of additional stacking motifs including edge-to-face, H - ? , cation-?, lone pair-? and anion-? interactions. Given the ubiquity and diversity of such motifs it seems reasonable to widen the meaning of stacking beyond the standard cofacial interactions between pairs of aromatics.

Egli, Martin

110

On Stacking  

NASA Astrophysics Data System (ADS)

The term ‘stacking' is normally associated with ? - ? interactions between aromatic moieties. The parallel alignment between adjacent DNA bases arguably constitutes the best-known example and provides the dominating contribution to the overall stability of DNA duplexes. Beyond canonical ? - ? interactions, a preliminary inspection of crystal structures of nucleic acids and their complexes with proteins reveals a wealth of additional stacking motifs including edge-to-face, H - ? , cation-?, lone pair-? and anion-? interactions. Given the ubiquity and diversity of such motifs it seems reasonable to widen the meaning of stacking beyond the standard cofacial interactions between pairs of aromatics.

Egli, Martin

111

An Interdisciplinary Study of Student Ability to Connect Particulate and Macroscopic Representations of a Gas  

NASA Astrophysics Data System (ADS)

This interdisciplinary project assessed the extent to which students in general education courses across two departments understood the assumptions of small-particle models and the ways in which these models relate to measurable properties. As part of this project, we embedded conceptually-oriented questions on written assessments in general education courses in physics and chemistry. Questions were drawn from the published literature in chemical and physics education and were developed by the research team. The results of this project provide a baseline measurement of the extent to which a diverse population of students in introductory physical science courses was able to develop and use particulate models to reason about macroscopic observables.

Monteyne, Kereen; Gonzalez, Barbara L.; Loverude, Michael E.

2008-10-01

112

Simultaneous particulates, NO sub x , SO sub x removal from flue gas by all solid-state electrochemical technology  

SciTech Connect

The process control SO{sub x}, NO{sub x}, and particulate emission from coal combustion flue gases. It is based on a solid-state, electrochemical reactor which converts NO{sub x} and SO{sub 2} to nitrogen, sulfur, and oxygen. Sulfur is condensed downstream at a lower temperature. Particulates are removed with a filter or electrostatic precipitator. The process utilizes no other material input (flue gas is the only fluid), has no moving parts, and produces no sludge(s). The reactor consists of an electrochemical cell where the electrolyte is a solid oxygen ion conducting ceramic such as stabilized ceria or zirconia and the electrodes are electronically conductive material(s). Porous metal such as silver or gold were used as electrodes in the experimental work. Acceptable reduction rates and electric power requirements for sulfur dioxide and nitrogen oxide removal were obtained in up to 1% oxygen with ruthenium and strontium ruthenate electrocatalysts. Electrocatalytic improvements are needed for higher oxygen concentrations, with the NO reduction rates and efficiencies being most sensitive to oxygen concentration. The best electrocatalysts were ruthenium and the perovskite strontium ruthenate. 37 refs., 23 figs., 26 tabs.

Cook, W.J.; Cornell, L.P.; Keyvani, M.; Neyman, M. (Helipump Corp., Cleveland, OH (USA)); Helfritch, D.J. (Research-Cottrell, Inc., Somerville, NJ (USA). Environmental Services and Technologies Div.)

1990-04-17

113

ALFALFA H I data stacking - III. Comparison of environmental trends in H I gas mass fraction and specific star formation rate  

NASA Astrophysics Data System (ADS)

It is well known that both the star formation rate and the cold gas content of a galaxy depend on the local density out to distances of a few Mpc. In this paper, we compare the environmental density dependence of the atomic gas mass fractions of nearby galaxies with the density dependence of their central and global specific star formation rates. We stack H I line spectra extracted from the Arecibo Legacy Fast ALFA survey centred on galaxies with ultraviolet imaging from GALEX and optical imaging/spectroscopy from Sloan Digital Sky Survey. We use these stacked spectra to evaluate the mean atomic gas mass fraction of galaxies in bins of stellar mass and local density. For galaxies with stellar masses less than 1010.5 M?, the decline in mean atomic gas mass fraction with density is stronger than the decline in mean global and central specific star formation rate. The same conclusion does not hold for more massive galaxies. We interpret our results as evidence for ram-pressure stripping of atomic gas from the outer discs of low-mass satellite galaxies. We compare our results with the semi-analytic recipes of Guo et al. implemented on the Millennium II Simulation. These models assume that only the diffuse gas surrounding satellite galaxies is stripped, a process that is often termed 'strangulation'. We show that these models predict relative trends in atomic gas and star formation that are in disagreement with observations. We use mock catalogues generated from the simulation to predict the halo masses of the H I-deficient galaxies in our sample. We conclude that ram-pressure stripping is likely to become effective in dark matter haloes with masses greater than 1013 M?.

Fabello, Silvia; Kauffmann, Guinevere; Catinella, Barbara; Li, Cheng; Giovanelli, Riccardo; Haynes, Martha P.

2012-12-01

114

Stacking Up  

ERIC Educational Resources Information Center

Chimneys and stacks appear to be strong and indestructible, but chimneys begin to deteriorate from the moment they are built. Early on, no signs are apparent; but deterioration accelerates in subsequent years, and major repairs are soon needed instead of minor maintenance. With proper attention, most structures can be repaired and continue to…

Naylor, Jim

2005-01-01

115

Stacking Up  

ERIC Educational Resources Information Center

|Chimneys and stacks appear to be strong and indestructible, but chimneys begin to deteriorate from the moment they are built. Early on, no signs are apparent; but deterioration accelerates in subsequent years, and major repairs are soon needed instead of minor maintenance. With proper attention, most structures can be repaired and continue to…

Naylor, Jim

2005-01-01

116

Isolation of mononitrated polycyclic aromatic hydrocarbons in particulate matter by liquid chromatography and determination by gas chromatography with the thermal energy analyzer  

Microsoft Academic Search

Nitrated polycyclic aromatic hydrocarbons (NPAH), which are extracted ultrasonically from particulate matter, are fractionated conveniently with a semipreparative scale high-pressure liquid chromatographic system. The NPAH present in the enriched isolate are determined by use of a gas chromatograph equipped with a thermal energy analyzer (TEA). Turnaround time is 8 h per sample. The HPLC separation permits selectivity for NPAH by

Bruce A. Tomkins; Roswitha S. Brazell; Mary E. Roth; Vanessa H. Ostrum

1984-01-01

117

Stack gas dispersion measurements with Large Scale-PIV, Aspiration Probes and Light Scattering Techniques and comparison with CFD  

Microsoft Academic Search

The main purpose of this research is to manage simultaneous measurement of velocity and concentration in large cross-sections by recording and processing images of cloud structures to provide more detailed information for e.g. validation of CFD simulations. Dispersion from an isolated stack in an Atmospheric Boundary Layer (ABL) was chosen as the test case and investigated both experimentally and numerically

Güne? Nakibo?lu; Catherine Gorlé; István Horváth; Jeroen van Beeck; Bert Blocken

2009-01-01

118

Sulfur Oxide Removal from Power Plant Stack Gas: Conceptual Design and Cost Study. Sorption by Limestone or Lime: Dry Process.  

National Technical Information Service (NTIS)

Previous studies have found that the injection of limestone or lime into a boiler will greatly reduce the amount of sulfur oxides in the stack gases. A scrubber may be used at the end of the system to enhance the degree of reaction; if such a device is no...

1968-01-01

119

Volatile organic compounds and particulates as components of diesel engine exhaust gas  

Microsoft Academic Search

Volatile organic compounds (VOC) and soot particles have been determined in a Diesel’s exhaust gas. A new sampling method allowed the measurement of emissions of organic compounds (C1 to C20) in a gas chromatogram at a detection limit of ca. 0.2 mg\\/m3. Particles were collected with a filter bed of ceramic particles and characterized by temperature programmed desorption (TPD) and

Hans Schulz; Gilberto Bandeira De Melo; Farid Ousmanov

1999-01-01

120

Trace Gas and Particulate Observations at the Marine Boundary Layer Site near Ucluelet on Vancouver Island  

NASA Astrophysics Data System (ADS)

In May 2010, a Marine Boundary Layer (MBL) station was established on the west coast of Vancouver Island near Ucluelet, B.C. Prevailing winds at the station are from the E to SE in the fall and winter and from the W to NW in the spring and summer. Observations of both trace gases (CO, O3, NOx, CO2, SO2...) as well as particulate measurements will be examined for background concentration of this MBL site and a number of interesting events including ozone depletion in the MBL and emission ratios from observed ship plumes both fresh and aged. Ozone concentrations have been observed to be reduced to 10-15ppb in the absence of NOx during the depletion events from background levels. The air measured at the site can be impacted by ships in the shipping lanes that converge into the Juan de Fuca Strait headed for Vancouver and Seattle as well as local fishing vessels. Emission ratios of both aged and fresh plumes will be examined.

Schiller, C. L.; Vingarzan, R.; Jones, K.; Leaitch, R.; Macdonald, A.; Mihele, C.; Graham, M.; Reid, K.

2011-12-01

121

Evaluation of methods for measuring particulate matter emissions from gas turbines.  

PubMed

The project SAMPLE evaluated methods for measuring particle properties in the exhaust of aircraft engines with respect to the development of standardized operation procedures for particulate matter measurement in aviation industry. Filter-based off-line mass methods included gravimetry and chemical analysis of carbonaceous species by combustion methods. Online mass methods were based on light absorption measurement or used size distribution measurements obtained from an electrical mobility analyzer approach. Number concentrations were determined using different condensation particle counters (CPC). Total mass from filter-based methods balanced gravimetric mass within 8% error. Carbonaceous matter accounted for 70% of gravimetric mass while the remaining 30% were attributed to hydrated sulfate and noncarbonaceous organic matter fractions. Online methods were closely correlated over the entire range of emission levels studied in the tests. Elemental carbon from combustion methods and black carbon from optical methods deviated by maximum 5% with respect to mass for low to medium emission levels, whereas for high emission levels a systematic deviation between online methods and filter based methods was found which is attributed to sampling effects. CPC based instruments proved highly reproducible for number concentration measurements with a maximum interinstrument standard deviation of 7.5%. PMID:21425830

Petzold, Andreas; Marsh, Richard; Johnson, Mark; Miller, Michael; Sevcenco, Yura; Delhaye, David; Ibrahim, Amir; Williams, Paul; Bauer, Heidi; Crayford, Andrew; Bachalo, William D; Raper, David

2011-03-22

122

Particulate Scrubbing Performance of the High Level Caves Off-Gas System  

SciTech Connect

Performance tests were conducted at the ETF using off-gas from the Small Cylindrical Melter (SCM) -2. The purpose of these tests was to develop data for comparing small and full scale equipment performance. This reports discusses those test results.

Wright, G.T.

2001-08-16

123

Trace gas and particulate emissions from the 2003 southern California wildfires  

Microsoft Academic Search

In October 2003, thirteen major wildfires in southern California burned more than 300,000 hectares of mainly chaparral biome. High-precision in situ trace gas and particle measurements of the wildfire plumes in La Jolla, California, showed a high degree of correlation among carbon dioxide (CO2), methane (CH4), nonmethane hydrocarbons, and methyl halide mixing ratios, as well as with particle number concentrations

J. Mühle; T. J. Lueker; Y. Su; B. R. Miller; K. A. Prather; R. F. Weiss

2007-01-01

124

Application of multicriteria decision making methods to compression ignition engine efficiency and gaseous, particulate, and greenhouse gas emissions.  

PubMed

Compression ignition (CI) engine design is subject to many constraints, which present a multicriteria optimization problem that the engine researcher must solve. In particular, the modern CI engine must not only be efficient but must also deliver low gaseous, particulate, and life cycle greenhouse gas emissions so that its impact on urban air quality, human health, and global warming is minimized. Consequently, this study undertakes a multicriteria analysis, which seeks to identify alternative fuels, injection technologies, and combustion strategies that could potentially satisfy these CI engine design constraints. Three data sets are analyzed with the Preference Ranking Organization Method for Enrichment Evaluations and Geometrical Analysis for Interactive Aid (PROMETHEE-GAIA) algorithm to explore the impact of (1) an ethanol fumigation system, (2) alternative fuels (20% biodiesel and synthetic diesel) and alternative injection technologies (mechanical direct injection and common rail injection), and (3) various biodiesel fuels made from 3 feedstocks (i.e., soy, tallow, and canola) tested at several blend percentages (20-100%) on the resulting emissions and efficiency profile of the various test engines. The results show that moderate ethanol substitutions (~20% by energy) at moderate load, high percentage soy blends (60-100%), and alternative fuels (biodiesel and synthetic diesel) provide an efficiency and emissions profile that yields the most "preferred" solutions to this multicriteria engine design problem. Further research is, however, required to reduce reactive oxygen species (ROS) emissions with alternative fuels and to deliver technologies that do not significantly reduce the median diameter of particle emissions. PMID:23343018

Surawski, Nicholas C; Miljevic, Branka; Bodisco, Timothy A; Brown, Richard J; Ristovski, Zoran D; Ayoko, Godwin A

2013-02-08

125

A gas-kinetic stability analysis of self-gravitating and collisional particulate disks with application to Saturn's rings  

NASA Astrophysics Data System (ADS)

Linear theory is used to determine the stability of the self-gravitating, rapidly (and nonuniformly) rotating, two-dimensional, and collisional particulate disk against small-amplitude gravity perturbations. A gas-kinetic theory approach is used by exploring the combined system of the Boltzmann and the Poisson equations. The effects of physical collisions between particles are taken into account by using in the Boltzmann kinetic equation a Krook model integral of collisions modified to allow collisions to be inelastic. It is shown that as a direct result of the classical Jeans instability and a secular dissipative-type instability of small-amplitude gravity disturbances (e.g. those produced by a spontaneous perturbation and/or a companion system) the disk is subdivided into numerous irregular ringlets, with size and spacing of the order of 4 ???2 ?h, where ?? cr/ ? is the mean epicyclic radius, cr is the radial dispersion of random velocities of particles, ? is the local epicyclic frequency, and h?2 ? is the typical thickness of the system. The present research is aimed above all at explaining the origin of various structures in highly flattened, rapidly rotating systems of mutually gravitating particles. In particular, it is suggested that forthcoming Cassini spacecraft high-resolution images may reveal this kind of hyperfine ˜2 ?h?100 m structure in the main rings A, B, and C of the Saturnian ring system.

Griv, Evgeny; Gedalin, Michael; Eichler, David; Yuan, Chi

2000-06-01

126

A gas-kinetic stability analysis of self-gravitating and collisional particulate disks with application to Saturn’s rings  

Microsoft Academic Search

Linear theory is used to determine the stability of the self-gravitating, rapidly (and nonuniformly) rotating, two-dimensional, and collisional particulate disk against small-amplitude gravity perturbations. A gas-kinetic theory approach is used by exploring the combined system of the Boltzmann and the Poisson equations. The effects of physical collisions between particles are taken into account by using in the Boltzmann kinetic equation

Evgeny Griv; Michael Gedalin; David Eichler; Chi Yuan

2000-01-01

127

Volatile organic compounds and particulates as components of diesel engine exhaust gas  

SciTech Connect

Volatile organic compounds (VOC) and soot particles have been determined in a Diesel`s exhaust gas. A new sampling method allowed the measurement of emissions of organic compounds (C{sub 1} to C{sub 20}) in a gas chromatogram at a detection limit of ca. 0.2 mg/m{sup 3}. Particles were collected with a filter bed of ceramic particles and characterized by temperature programmed desorption (TPD) and oxidation (TPO). Engine runs were always performed at a fixed and constant air to fuel equivalence ratio ({lambda}) and with a constant volumetric efficiency, because these parameters strongly influenced the emissions in terms of both composition and order of magnitude. The effective combustion temperature again strongly governed the nature of the emissions. Model fuels, composed of individual paraffins and aromatics and additions of sulfur compounds and an organic nitrate (for cetane number enhancement) were used. The results contribute to the understanding of the origin of specific emissions from Diesel engines. These newly developed methods are recommended for further application.

Schulz, H.; Bandeira de Melo, G.; Ousmanov, F. [Univ. of Karlsruhe (Germany). Engler-Bunte-Inst.

1999-07-01

128

Modular fuel-cell stack assembly  

SciTech Connect

A fuel cell assembly having a plurality of fuel cells arranged in a stack. An end plate assembly abuts the fuel cell at an end of said stack. The end plate assembly has an inlet area adapted to receive an exhaust gas from the stack, an outlet area and a passage connecting the inlet area and outlet area and adapted to carry the exhaust gas received at the inlet area from the inlet area to the outlet area. A further end plate assembly abuts the fuel cell at a further opposing end of the stack. The further end plate assembly has a further inlet area adapted to receive a further exhaust gas from the stack, a further outlet area and a further passage connecting the further inlet area and further outlet area and adapted to carry the further exhaust gas received at the further inlet area from the further inlet area to the further outlet area.

Patel, Pinakin (Danbury, CT)

2010-07-13

129

Innovative application of Fluoro-tagging to trace airborne particulate and gas phase PBDE exposures  

PubMed Central

Polybrominated diphenyl ethers (PBDEs) are flame retardants applied as coatings to many consumer products, including household items. PBDEs are released and produce airborne vapors and dusts. Inhalation of particle-phase and/or gas-phase PBDEs is therefore a major route of exposure. In an attempt to mimic realistic airborne exposures, actual uptake and deposition of particles and vapors, we prepared and characterized particles for future animal exposure studies. To trace the particles in environmental and biological systems, we employed fluoro-tagging. We synthesized, characterized and employed three PBDE congeners 35, 47 and 99, and five fluoro-substituted-PBDEs (F-PBDEs), 17-F5?, 25-F5?, 28-F3?, 35-F5?, 47-F3, 99-F3? for this study. The PBDE congeners were selected because they are commonly found in house dust. For that reason we coated spherical silica particles of 3 ?m and C18 endcapped silica as representative and inert support materials, with 20%, 30% and 40% PBDEs. We determined the particle size distributions by aerodynamic particle size spectrometry and the morphology by scanning electron microscopy. The suitability of the fluoro-tagged tracers to mimic their corresponding parent PBDEs was investigated by extraction studies from spiked blood serum. Our study is of fundamental importance to the development of xenobiotic tracers for monitoring routes of human exposure to PBDEs and understanding uptake of PBDEs from particles and vapors.

Klosener, Johannes; Peters, Thomas M.; Adamcakova-Dodd, Andrea; Teesch, Lynn; Thorne, Peter S.; Robertson, Larry W.; Luthe, Gregor

2009-01-01

130

Size distribution of alkyl amines in continental particulate matter and their online detection in the gas and particle phase  

NASA Astrophysics Data System (ADS)

An ion chromatographic method is described for the quantification of the simple alkyl amines: methylamine (MA), dimethylamine (DMA), trimethylamine (TMA), ethylamine (EA), diethylamine (DEA) and triethylamine (TEA), in the ambient atmosphere. Limits of detection (3?) are in the tens of pmol range for all of these amines, and good resolution is achieved for all compounds except for TMA and DEA. The technique was applied to the analysis of time-integrated samples collected using a micro-orifice uniform deposition impactor (MOUDI) with ten stages for size resolution of particles with aerodynamic diameters between 56 nm and 18 ?m. In eight samples from urban and rural continental airmasses, the mass loading of amines consistently maximized on the stage corresponding to particles with aerodynamic diameters between 320 and 560 nm. The molar ratio of amines to ammonium (R3NH+/NH4+) in fine aerosol ranged between 0.005 and 0.2, and maximized for the smallest particle sizes. The size-dependence of the R3NH+/NH4+ ratio indicates differences in the relative importance of the processes leading to the incorporation of amines and ammonia into secondary particles. The technique was also used to make simultaneous hourly online measurements of amines in the gas phase and in fine particulate matter using an Ambient Ion Monitor Ion Chromatograph (AIM-IC). During a ten day campaign in downtown Toronto, DMA, TMA+DEA, and TEA were observed to range from below detection limit to 2.7 ppt in the gas phase. In the particle phase, MAH+ and TMAH++DEAH+ were observed to range from below detection limit up to 15 ng m-3. The presence of detectable levels of amines in the particle phase corresponded to periods with higher relative humidity and higher mass loadings of nitrate. While the hourly measurements made using the AIM-IC provide data that can be used the evaluate the application of gas-particle partitioning models to amines, the strong size-dependence of the R3NH+/NH4+ ratio indicates that using bulk measurements and an assumption of internal mixing may not be appropriate.

Vandenboer, T. C.; Petroff, A.; Markovic, M. Z.; Murphy, J. G.

2010-11-01

131

Characterization of stack emissions from municipal refuse-to-energy systems. Final report  

Microsoft Academic Search

Stack emissions from three municipal refuse-to-energy systems were characterized: refuse-derived fuel (RDF), mass burning (MASS), and modular (MOD). A comprehensive set of measurements was performed at each site to determine the physical and chemical properties of the particulate and gaseous stack emissions. The physical characterization included measurement of the mass concentration and size distribution of the stack particulate matter. Inorganic

J. E. Howes; D. F. Kohler; F. L. DeRoos; R. M. Riggin; R. L. Barbour

1986-01-01

132

Composition, toxicity, and mutagenicity of particulate and semivolatile emissions from heavy-duty compressed natural gas-powered vehicles.  

PubMed

Particulate matter (PM) and vapor-phase semivolatile organic compounds (SVOC) were collected from three buses fueled by compressed natural gas. The bus engines included a well-functioning, conventional engine; a "high emitter" engine; and a new technology engine with an oxidation catalyst. Chemical analysis of the emissions showed differences among these samples, with the high emitter sample containing markers of engine oil constituents. PM + SVOC samples were also collected for mutagenicity and toxicity testing. Extraction efficiencies from the collection media were lower than for similarly collected samples from gasoline or diesel vehicles. Responses to the recovered samples were compared on the basis of exhaust volume, to incorporate the emission rates into the potency factors. Mutagenicity was assessed by Salmonella reverse mutation assay. Mutagenicity was greatest for the high emitter sample and lowest for the new technology sample. Metabolic activation reduced mutagenicity in strain TA100, but not TA98. Toxicity, including inflammation, cytotoxicity, and parenchymal changes, was assessed 24 h after intratracheal instillation into rat lungs. Lung responses were generally mild, with little difference between the responses to equivalent volumes of emissions from the normal emitter and the new technology, but greater responses for the high emitter. These emission sample potencies are further compared on the basis of recovered mass with previously reported samples from normal and high-emitter gasoline and diesel vehicles. While mutagenic potencies for the CNG emission samples were similar to the range observed in the gasoline and diesel emission samples, lung toxicity potency factors were generally lower than those for the gasoline and diesel samples. PMID:15976195

Seagrave, JeanClare; Gigliotti, Andrew; McDonald, Jacob D; Seilkop, Steven K; Whitney, Kevin A; Zielinska, Barbara; Mauderly, Joe L

2005-06-23

133

40 CFR 86.1320-90 - Gas meter or flow instrumentation calibration; particulate, methanol, and formaldehyde measurement.  

Code of Federal Regulations, 2013 CFR

...calibration system at the sample flow rate used for particulate, methanol...of this section using at least two flow rates which bracket the typical operating...calibration measurement at the specified flow rates using the criteria of...

2013-07-01

134

40 CFR 86.120-94 - Gas meter or flow instrumentation calibration; particulate, methanol and formaldehyde measurement.  

Code of Federal Regulations, 2013 CFR

...calibration system at the sample flow rate used for particulate, methanol...of this section using at least two flow rates which bracket the typical operating...calibration measurement at the specified flow rates using the criteria of...

2013-07-01

135

The use of a housecleaning product in an indoor environment leading to oxygenated polar compounds and SOA formation: Gas and particulate phase chemical characterization  

NASA Astrophysics Data System (ADS)

This work investigates Secondary Organic Aerosol (SOA) formed by limonene ozonolysis using a housecleaning product in indoor environment. This study combines simulation chamber ozonolysis experiments and field studies in an experimental house allowing different scenarios of housecleaning product use in real conditions. Chemical speciation has been performed using a new method based on simultaneous sampling of both gas and particulate phases on sorbent tubes and filters. This method allowed the identification and quantification of about 35 products in the gas and particulate phases. Among them, products known to be specific from limonene ozonolysis such as limononaldehyde, ketolimonene and ketolimonic acid have been detected. Some other compounds such as 2-methylbutanoic acid had never been detected in previous limonene ozonolysis studies. Some compounds like levulinic acid had already been detected but their formation remained unexplained. Potential reaction pathways are proposed in this study for these compounds. For each experiment, chemical data are coupled together with physical characterization of formed particles: mass and size and number distribution evolution which allowed the observation of new particles formation (about 87,000 particle cm-3). The chemical speciation associated to aerosol size distribution results confirmed that limonene emitted by the housecleaning product was responsible for SOA formation. To our knowledge, this work provides the most comprehensive analytical study of detected compounds in a single experiment for limonene ozonolysis in both gaseous and particulate phases in real indoor environment.

Rossignol, S.; Rio, C.; Ustache, A.; Fable, S.; Nicolle, J.; Même, A.; D'Anna, B.; Nicolas, M.; Leoz, E.; Chiappini, L.

2013-08-01

136

Novel optical scattering collection system for particulate monitoring applications.  

National Technical Information Service (NTIS)

Light collecting systems often require radically different optical surfaces than those commonly found in optical imaging systems. An optical particulate monitor must probe a volume in emission stacks to obtain a good statistical distribution of suspended ...

B. E. Bernacki A. C. Miller R. J. Nuspliger

1996-01-01

137

Effects of particulates, heavy metals and acid gas on the removals of NO and PAHs by V2O5-WO3 catalysts in waste incineration system.  

PubMed

This study investigated the activities of prepared and commercial V(2)O(5)-WO(3) catalysts for simultaneous removals of NO and polycyclic aromatic hydrocarbons (PAHs) and the influences of particulates, heavy metals, SO(2), and HCl on the performances of catalysts. The experiments were carried out in a laboratory-scale waste incineration system equipped with a catalyst reactor. The DREs of PAHs by prepared and commercial V(2)O(5)-WO(3) catalysts were 64% and 72%, respectively. Increasing the particulate concentrations in flue gas suppressed the DRE of PAHs, but increasing the carbon content on surface of catalysts promotes the NO conversions. The DRE of PAHs by the catalysts was significantly decreased by the increased concentrations of heavy metal Cd, but was promoted by high concentration of Pb. The influence level of SO(2) was higher than HCl on the performances of V(2)O(5)-WO(3) catalysts for PAHs removal, but was lower than HCl for NO removal. Prepared and commercial V(2)O(5)-WO(3) catalysts have similar trends on the effects of particulates, heavy metals, SO(2), and HCl. The results of ESCA analysis reveal that the presence of these pollutants on the surface of catalysts did not change the chemical state of V and W. PMID:19500905

Chang, Feng-Yim; Chen, Jyh-Cherng; Wey, Ming-Yen; Tsai, Shih-An

2009-05-04

138

Physics and chemistry of E-beam stack gas processing. Final report, 20 September 1982-14 January 1984  

SciTech Connect

The purpose of this program is to investigate some of the basic physics and chemistry of the electron beam induced NO/sub x/ and SO/sub x/ removal process. The program involves both kinetic modelling and diagnostic development. The development of an adequate kinetic model is necessary in order to scale the laboratory results, which are currently available, to process conditions closer to those that will be encountered at full scale operation. It is also necessary in order to place the laboratory data on a firm theoretical foundation. The development of real time optical diagnostics is a necessary supporting task for these goals in order to obtain kinetic data on some of the myriad of species that are present in this hostile environment (X-rays present; hot, acidic gas) which is difficult to access by conventional methods. This particular NO/sub x//SO/sub x/ removal process involves the irradiation of combustion products t temperatures around 100/sup 0/C with a beam of high energy electrons. The current study expands upon the mechanistic studies. A detailed kinetic model is described which includes all the necessary assumptions that enter in order to take the very large number of possible processes that occur in e-beam irradiated mixtures and reduce them to some tractable number. Quantitative comparisons are then made between the kinetic model and experimental data. Another phase of this program is the development of laser diagnostics to probe various species in the irradiated flue gas. The experimental phase of program is first described including a discussion of our e-beam facility and the methods used to accurately measure energy deposition. A description of the laser diagnostics follows. 37 references, 22 figures, 7 tables.

Slater, R.

1983-10-01

139

Stack Monitor Operating Experience Review  

SciTech Connect

Stack monitors are used to sense radioactive particulates and gases in effluent air being vented from rooms of nuclear facilities. These monitors record the levels and types of effluents to the environment. This paper presents the results of a stack monitor operating experience review of the U.S. Department of Energy (DOE) Occurrence Reporting and Processing System (ORPS) database records from the past 18 years. Regulations regarding these monitors are briefly described. Operating experiences reported by the U.S. DOE and in engineering literature sources were reviewed to determine the strengths and weaknesses of these monitors. Electrical faults, radiation instrumentation faults, and human errors are the three leading causes of failures. A representative “all modes” failure rate is 1E-04/hr. Repair time estimates vary from an average repair time of 17.5 hours (with spare parts on hand) to 160 hours (without spare parts on hand). These data should support the use of stack monitors in any nuclear facility, including the National Ignition Facility and the international ITER project.

L. C. Cadwallader; S. A. Bruyere

2009-05-01

140

Development of a gas chromatography-mass spectrometry method for the determination of pesticides in gaseous and particulate phases in the atmosphere.  

PubMed

A reliable multi-residue method for determining gaseous and particulate phase pesticides in atmospheric samples has been developed. This method, based on full scan gas chromatography-mass spectrometry (GC-MS), allowed the proper determination of sixteen relevant pesticides, in a wide range of concentrations and without the influence of interferences. The pesticides were benfluralin, bitertanol, buprofezin, chlorfenvinphos, chlorpyrifos, chlorpyrifos-methyl, ethalfluralin, fenthion, lindane, malathion, methidathion, propachlor, propanil, pyriproxifen, tebuconazol and trifluralin. Comparisons of two types of sampling filters (quartz and glass fibre) and four types of solid-phase cartridges (XAD-2, XAD-4, Florisil and Orbo-49P) showed that the most suitable supports were glass fibre filter for particulate pesticides and XAD-2 and XAD-4 cartridges for gaseous pesticides (>95% recovery). Evaluations of elution solvents for ultrasonic-assisted extraction demonstrated that isooctane is better than ethylacetate, dichloromethane, methanol or a mixture of acetone:hexane (1:1). Recovery assays and the standard addition method were performed to validate the proposed methodology. Moreover, large simulator chamber experiments allowed the best study of the gas-particle partitioning of pesticides for testing the sampling efficiency for the validation of an analytical multiresidue method for pesticides in air. Satisfactory analytical parameters were obtained, with a repeatability of 5±1%, a reproducibility of 13±3% and detection limits of 0.05-0.18 pg m(-3) for the particulate phase and 26-88 pg m(-3) for the gaseous phase. Finally, the methodology was successfully applied to rural and agricultural samples in the Mediterranean area. PMID:21704758

Borrás, E; Sánchez, P; Muñoz, A; Tortajada-Genaro, L A

2011-05-14

141

Application of modern online instrumentation for chemical analysis of gas and particulate phases of exhaust at the European Commission heavy-duty vehicle emission laboratory.  

PubMed

The European Commission recently established a novel test facility for heavy-duty vehicles to enhance more sustainable transport. The facility enables the study of energy efficiency of various fuels/scenarios as well as the chemical composition of evolved exhaust emissions. Sophisticated instrumentation for real-time analysis of the gas and particulate phases of exhaust has been implemented. Thereby, gas-phase characterization was carried out by a Fourier transform infrared spectrometer (FT-IR; carbonyls, nitrogen-containing species, small hydrocarbons) and a resonance-enhanced multiphoton ionization time-of-flight mass spectrometer (REMPI-TOFMS; monocyclic and polycyclic aromatic hydrocarbons). For analysis of the particulate phase, a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS; organic matter, chloride, nitrate), a condensation particle counter (CPC; particle number), and a multiangle absorption photometer (MAAP; black carbon) were applied. In this paper, the first application of the new facility in combination with the described instruments is presented, whereby a medium-size truck was investigated by applying different driving cycles. The goal was simultaneous chemical characterization of a great variety of gaseous compounds and particulate matter in exhaust on a real-time basis. The time-resolved data allowed new approaches to view the results; for example, emission factors were normalized to time-resolved consumption of fuel and were related to emission factors evolved during high speeds. Compounds could be identified that followed the fuel consumption, others showed very different behavior. In particular, engine cold start, engine ignition (unburned fuel), and high-speed events resulted in unique emission patterns. PMID:21126058

Adam, T W; Chirico, R; Clairotte, M; Elsasser, M; Manfredi, U; Martini, G; Sklorz, M; Streibel, T; Heringa, M F; Decarlo, P F; Baltensperger, U; De Santi, G; Krasenbrink, A; Zimmermann, R; Prevot, A S H; Astorga, C

2010-12-02

142

Effect of modified phosphate rock saturated by various salts on stack gas desulfurization in a fluidized bed reactor  

SciTech Connect

In this work, the suitability of phosphate ore treated with the varied salts such as FeSO{sub 4}, NaCl, CaCl{sub 2}, Na{sub 2}SiO{sub 3}, and Na{sub 2}SO{sub 4} as an alternative material for limestone and dolomite in flue gas desulfurization has been investigated. Also, the effect of the varied salts on calcination and sulfation of the raw, calcine, and semicalcined phosphate samples has been investigated in a differential fluidized bed reactor at 700-800{sup o}C (4 min) in air and 0.3% SO{sub 2}. It was established that the salts have prominent effects on sulfation and calcination. The changes in the pore structure and products obtained at the end of sulfation were investigated using BET surface area method. In conclusion, it was observed that the sulfation and calcination conversion ratios generally increased when the phosphate rock was treated the varied salts.

Kar, Y.; Kar, H. [Selcuk University, Konya (Turkey). Muhendislik Mimarlik Faculty

2006-04-15

143

40 CFR Appendix Vi to Part 266 - Stack Plume Rise  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Stack Plume Rise VI Appendix VI to Part 266...App. VI Appendix VI to Part 266âStack Plume Rise [Estimated Plume Rise (in Meters) Based on Stack Exit Flow Rate and Gas Temperature]...

2012-07-01

144

Condensation cleaning of particulate laden gases  

SciTech Connect

Particulate laden gas, especially those gases carrying particulates having a size in the micron or submicron range, are removed by humidifying the gas with water and thereafter subjecting the gas to indirect contact heat exchange sufficient to provide an energy transfer for water vapor condensation of at least 5 horsepower per 1000 cfm. Heat exchange is accomlished by passing the gas downwardly through an exchange element having smooth and vertical gas passages of a relatively large dimension.

Devries, E.

1981-08-18

145

Nature and magnitude of aromatic stacking of nucleic acid bases.  

PubMed

This review summarises recent advances in quantum chemical calculations of base-stacking forces in nucleic acids. We explain in detail the very complex relationship between the gas-phase base-stacking energies, as revealed by quantum chemical (QM) calculations, and the highly variable roles of these interactions in nucleic acids. This issue is rarely discussed in quantum chemical and physical chemistry literature. We further extensively discuss methods that are available for base-stacking studies, complexity of comparison of stacking calculations with gas phase experiments, balance of forces in stacked complexes of nucleic acid bases, and the relation between QM and force field descriptions. We also review all recent calculations on base-stacking systems, including details analysis of the B-DNA stacking. Specific attention is paid to the highest accuracy QM calculations, to the decomposition of the interactions, and development of dispersion-balanced DFT methods. Future prospects of computational studies of base stacking are discussed. PMID:18464974

Sponer, Jirí; Riley, Kevin E; Hobza, Pavel

2008-04-07

146

DEVELOPMENT OF FINE PARTICULATE EMISSION FACTORS AND SPECIATION PROFILES FOR OIL AND GAS-FIRED COMBUSTION SYSTEMS  

Microsoft Academic Search

In 1997, the United States Environmental Protection Agency (EPA) promulgated new National Ambient Air Quality Standards (NAAQS) for particulate matter, including for the first time particles with aerodynamic diameter smaller than 2.5 micrometers (μm) referred to as PM2.5. PM2.5 in the atmosphere also contributes to reduced atmospheric visibility, which is the subject of existing rules for siting emission sources near

Glenn C. England

2004-01-01

147

Determination of nitrated polynuclear aromatic hydrocarbons in particulate extracts by capillary column gas chromatography with nitrogen selective detection  

Microsoft Academic Search

The highly complex matrix of a diesel particulate extract was analyzed for nitrated polynuclear aromatic hydrocarbons (nitro-PAH) by use of fused-silica capillary column GC\\/thermionic nitrogen-phosphorus (GC\\/NPD) analysis of HPLC fractions. These samples were found to contain at least 100 nitro-PAH. Positive isomer identification for 17 nitro-PAH has been made utilizing the GC retention times of authentic standards and low- and

M. C. Paputa-Peck; R. S. Marano; Dennis. Schuetzle; T. L. Riley; C. V. Hampton; T. J. Prater; L. M. Skewes; T. E. Jensen; P. H. Ruehle; L. C. Bosch

1983-01-01

148

Understanding Java Stack Inspection  

Microsoft Academic Search

Current implementations of Java make security decisions by searching the runtime call stack. These systems have attractive security properties, but they have been criticized as being dependent on specific artifacts of the Java imple- mentation. This paper models the stack inspection algorithm in terms of a well-understood logic for access control and demonstrates how stack inspection is a useful tool

Dan S. Wallach; Edward W. Felten

1998-01-01

149

Particulate Matter Emissions from a Coal-Fired Power Plant  

Microsoft Academic Search

Particulate matter emissions of filterable particulate matter (FPM), condensible PM (CPM), PM10, and PM2.5 at FGD inlet and stack in a coal-fired power plant were measured by EPA method 201A and method 202. The results indicated that emissions of total particulate matter (TPM) are 40.99mg\\/m3 and 120.58mg\\/m3, and the filterable PMs are the highest emissions at both sampling locations which

Ping Lu; Jiang Wu; Wei-Ping Pan

2010-01-01

150

Stacking of Interferometric Data  

NASA Astrophysics Data System (ADS)

Radio and mm observations play an important role in determining the star formation properties of high redshift galaxies. However, most galaxies at high redshift are too faint to be detected individually at these wavelengths. A way to study this population of galaxies is to use stacking. By averaging the emission of a large number of galaxies detected in optical or near infrared surveys, we can achieve statistical detection. We investigate methods for stacking data from interferometric surveys. Interferometry poses unique challenges in stacking due to the nature of imaging of this data. We have compared directly stacking the uv data with stacking of the imaged data, the latter being the typically used approach. Using simulated data, we find that uv-stacking may provide around 50% less noise and that image based stacking systematically loses around 10% of the flux.

Lindroos, Lukas; Knudsen, Kirsten K.

2013-07-01

151

Analysis of semi-volatile organic compounds in indoor suspended particulate matter by thermal desorption coupled with gas chromatography/mass spectrometry.  

PubMed

People are exposed to multiple pollutants, especially indoors. In the perspective of a cumulative risk assessment, a multi-residue analytical method was developed to assess the contamination of indoor suspended particulate matter by 55 semi-volatile organic compounds (SVOCs) including musk fragrances, organochlorines (OCs), organophosphates (OPs), polycyclic aromatic hydrocarbons (PAHs), polybromodiphenylethers (PBDEs), polychlorobiphenyls (PCBs), phthalates and pyrethroids. It is based on thermal desorption (TD) coupled with gas chromatography/mass spectrometry (GC/MS). Once the thermal desorption conditions were optimized, the method was validated in terms of quantification limits and accuracy using a standard reference material (SRM 2585). Instrumental quantification limits were 10 pg (some OCs, some pyrethroids, musk fragrances, OPs, PAHs, PBDEs and PCBs), 100 pg (phthalates and other OCs) and 1000 pg (other pyrethroids) corresponding respectively to method quantification limits of 1, 10, and 100 pg/m³ for a sampled air volume of 20 m³. Calibration quadratic curves for ranges of 10-1000, 100-10,000, and 1000-100,000 pg, depending on the substance, exhibit determination coefficients above 0.999. Recoveries were between 61 and 96% for chlorinated pesticides, PAHs, PBDEs and PCBs present in the SRM 2585. A test of the method on indoor particulate matter samples (PM??) collected on quartz fiber filters in French dwellings demonstrated its ability to quantify SVOCs from a small amount of PM. PMID:22840824

Mercier, Fabien; Glorennec, Philippe; Blanchard, Olivier; Le Bot, Barbara

2012-07-16

152

Stacking with stochastic cooling  

NASA Astrophysics Data System (ADS)

Accumulation of large stacks of antiprotons or ions with the aid of stochastic cooling is more delicate than cooling a constant intensity beam. Basically the difficulty stems from the fact that the optimized gain and the cooling rate are inversely proportional to the number of particles `seen' by the cooling system. Therefore, to maintain fast stacking, the newly injected batch has to be strongly `protected' from the Schottky noise of the stack. Vice versa the stack has to be efficiently `shielded' against the high gain cooling system for the injected beam. In the antiproton accumulators with stacking ratios up to 105 the problem is solved by radial separation of the injection and the stack orbits in a region of large dispersion. An array of several tapered cooling systems with a matched gain profile provides a continuous particle flux towards the high-density stack core. Shielding of the different systems from each other is obtained both through the spatial separation and via the revolution frequencies (filters). In the `old AA', where the antiproton collection and stacking was done in one single ring, the injected beam was further shielded during cooling by means of a movable shutter. The complexity of these systems is very high. For more modest stacking ratios, one might use azimuthal rather than radial separation of stack and injected beam. Schematically half of the circumference would be used to accept and cool new beam and the remainder to house the stack. Fast gating is then required between the high gain cooling of the injected beam and the low gain stack cooling. RF-gymnastics are used to merge the pre-cooled batch with the stack, to re-create free space for the next injection, and to capture the new batch. This scheme is less demanding for the storage ring lattice, but at the expense of some reduction in stacking rate. The talk reviews the `radial' separation schemes and also gives some considerations to the `azimuthal' schemes.

Caspers, Fritz; Möhl, Dieter

2004-10-01

153

Study on Stack Gas Diffusion.  

National Technical Information Service (NTIS)

The useful and effective control of air pollution can be done not only by technical measures such as removal of pollutants in fuel and smoke, and atmospheric diffusion-dilution of pollutants, but also by estimation and countermeasures for anti-airpollutio...

N. Ukeguchi H. Sakata H. Okameto Y. Ide

1967-01-01

154

Size mass distribution of water-soluble ionic species and gas conversion to sulfate and nitrate in particulate matter in southern Taiwan.  

PubMed

A Micro-Orifice Uniform Deposition Impactor (MOUDI) and a Nano-MOUDI were employed to determine the size-segregated mass distributions of ambient particulate matter (PM) and water-soluble ionic species for particulate constituents. In addition, gas precursors, including HCl, HONO, HNO3, SO2, and NH3 gases, were analyzed by an annular denuder system. PM size mass distribution, mass concentration, and ionic species concentration were measured during the day and at night during episode and non-episode periods in winter and summer. Average total suspended particle (TSP) concentrations during episode days in winter were as high as 153?±?33 ?g/m(3), and PM mass concentrations in summer were as low as one-third of that in winter. Generally, PM concentration at night was higher than that in the daytime in southern Taiwan during the sampling periods. In winter during the episode periods, the size-segregated mass distribution of PM mass concentration was mostly in the 0.32-3.2-?m range, and the PM concentration increased significantly in the range of 0.32-3.2 ?m at night. Ammonium, nitrate, and sulfate were the dominant water-soluble ionic species in PM, contributing 34-48% of TSP mass. High concentrations of ammonia (12.9-49 ?g/m(3)) and SO2 (2.6-27 ?g/m(3)) were observed in the gas precursors. The conversion ratio was high in the PM size range of 0.18-3.2 ?m both during the day and at night in winter, and the conversion ratio of episode days was 20% higher than that of non-episode days. The conversion factor was high for both nitrogen and sulfur species at nighttime, especially on episode days. PMID:23263756

Tsai, Jiun-Horng; Chang, Li-Peng; Chiang, Hung-Lung

2012-12-21

155

Ion chromatographic separation and quantitation of alkyl methylamines and ethylamines in atmospheric gas and particulate matter using preconcentration and suppressed conductivity detection.  

PubMed

Two methods based on ion chromatography (IC) were developed for the detection of methyl and ethyl alkyl amines (methylamine (MA), ethylamine (EA), dimethylamine (DMA), diethylamine (DEA), trimethylamine (TMA) and triethylamine (TEA)) and NH(3)/NH(4)(+) in online atmospheric gas-particle and size-resolved particulate samples. The two IC methods were developed to analyze samples collected with an ambient ion monitor (AIM), an online gas-particle collection system, or with a Micro Orifice Uniform Deposit Impactor (MOUDI) for size-resolved particle samples. These methods enable selective and (semi-) quantitative detection of alkyl amines at ambient atmospheric concentrations (pptv and pgm(-3)) in samples where significant interferences can be expected from Na(+) and NH(4)(+), for example marine and rural air masses. Sample pre-concentration using a trace cation column enabled instrumental detection limits on the order of pmol (sub-ng) levels per sample, an improvement of up to 10(2) over current IC methods. Separation was achieved using a methanesulfonic acid gradient elution on Dionex CS12A and CS17 columns. The relative standard deviations in retention times during 3 weeks continuous (hourly) sampling campaigns ranged from 0.1 to 0.5% and 0.2 to 5% for the CS12A and CS17 across a wide dynamic range of atmospheric concentrations. Resolution of inorganic and organic cations is limited to 25min for online samples. Mass-dependent coelution of NH(4)(+)/MA/EA occurred on the CS12A column and DEA/TMA coeluted on both columns. Calibrations of ammonium show a non-linear response across the entire calibration range while all other analytes exhibit high linearity (R(2)=0.984-0.999), except for EA and TEA on the CS12A (R(2)=0.960 and 0.941, respectively). Both methods have high analytical accuracy for the nitrogenous bases ranging from 9.5 to 20% for NH(3) and <5-15% for the amines. Hourly observations of amines at Egbert, ON in October 2010 showed gaseous DMA and TMA+DEA at 1-10pptv in air, while particulate DMA and TMA+DEA were present at 0.5-4ng m(-3). A size-resolved particulate sample collected over 23h was found to contain DMA, TMA+DEA and MEA at 1.78, 8.15 and 0.03ngm(-3) mass loadings, with the amine mass enhanced in particle sizes between 100 and 1000nm. These results highlight a need for very sensitive and selective detection of methyl and ethyl amines in addition to NH(3) in continuous online monitoring strategies. PMID:22784696

VandenBoer, T C; Markovic, M Z; Petroff, A; Czar, M F; Borduas, N; Murphy, J G

2012-06-26

156

40 CFR 86.210-08 - Exhaust gas sampling system; Diesel-cycle vehicles not requiring particulate emissions measurements.  

Code of Federal Regulations, 2011 CFR

...of this chapter, except that heated flame ionization detector (HFID), probe...diesel-cycle vehicles require a heated flame ionization detector (HFID) (375...gas-fueled diesel vehicles either a heated flame ionization detector (HFID)...

2011-07-01

157

Polycyclic aromatic hydrocarbons in gas and particulate phases of indoor environments influenced by tobacco smoke: Levels, phase distributions, and health risks  

NASA Astrophysics Data System (ADS)

As polycyclic aromatic hydrocarbons (PAHs) have a negative impact on human health due to their mutagenic and/or carcinogenic properties, the objective of this work was to study the influence of tobacco smoke on levels and phase distribution of PAHs and to evaluate the associated health risks. The air samples were collected at two homes; 18 PAHs (the 16 PAHs considered by U.S. EPA as priority pollutants, dibenzo[a,l]pyrene and benzo[j]fluoranthene) were determined in gas phase and associated with thoracic (PM 10) and respirable (PM 2.5) particles. At home influenced by tobacco smoke the total concentrations of 18 PAHs in air ranged from 28.3 to 106 ng m -3 (mean of 66.7 ± 25.4 ng m -3), ? PAHs being 95% higher than at the non-smoking one where the values ranged from 17.9 to 62.0 ng m -3 (mean of 34.5 ± 16.5 ng m -3). On average 74% and 78% of ? PAHs were present in gas phase at the smoking and non-smoking homes, respectively, demonstrating that adequate assessment of PAHs in air requires evaluation of PAHs in both gas and particulate phases. When influenced by tobacco smoke the health risks values were 3.5-3.6 times higher due to the exposure of PM 10. The values of lifetime lung cancer risks were 4.1 × 10 -3 and 1.7 × 10 -3 for the smoking and non-smoking homes, considerably exceeding the health-based guideline level at both homes also due to the contribution of outdoor traffic emissions. The results showed that evaluation of benzo[a]pyrene alone would probably underestimate the carcinogenic potential of the studied PAH mixtures; in total ten carcinogenic PAHs represented 36% and 32% of the gaseous ? PAHs and in particulate phase they accounted for 75% and 71% of ? PAHs at the smoking and non-smoking homes, respectively.

Castro, Dionísia; Slezakova, Klara; Delerue-Matos, Cristina; Alvim-Ferraz, Maria da Conceição; Morais, Simone; Pereira, Maria do Carmo

2011-04-01

158

Stack automata and compiling  

Microsoft Academic Search

Compilation consists of two parts, recognition and translation. A mathematical model is presented which embodies salient features of many modern compiling techniques. The model, called the stack automaton, has the desirable feature of being deterministic in nature. This deterministic device is generalized to a nondeterministic device (nondeterministic stack automaton) and particular instances of this more general device are noted. Sets

Seymour Ginsburg; Sheila A. Greibach; Michael A. Harrison

1967-01-01

159

StackGhost: Hardware Facilitated Stack Protection  

Microsoft Academic Search

Conventional security exploits have relied on over- writing the saved return pointer on the stack to hijack the path of execution. Under Sun Micro- system's Sparc processor architecture, we were able to implement a kernel modification to transparently and automatically guard applications' return point- ers.

Mike Frantzen; Mike Shuey

2001-01-01

160

Tunneling through nanographene stacks  

NASA Astrophysics Data System (ADS)

We present a scanning tunneling microscopy (STM) and spectroscopy (STS) study of a nanographene, hexa-peri-hexabenzocoronene (HBC), in different stacked geometries, covalently bound in cyclophanes or physisorbed in double layers consisting either of HBCs only or of a mixture of HBC and an alkylated disk-type electron acceptor, coronenediimide. Tunneling bias-dependent STM and STS at the solid-liquid interface reveal that the lateral offset between the stacked molecules strongly influences the electron transport through the stacks, which is attributed to different highest occupied and lowest unoccupied molecular orbital splittings in the stacks. The results imply that the control over the stacking in nanographene multilayers or columns can be used to control their electron transport properties.

Jäckel, F.; Watson, M. D.; Müllen, K.; Rabe, J. P.

2006-01-01

161

Short protection device for stack of electrolytic cells  

DOEpatents

Electrical short protection is provided in an electrolytic cell stack by the combination of a thin, nonporous ceramic shield and a noble metal foil disposed on opposite sides of the sealing medium in a gas manifold gasket. The thin ceramic shield, such as alumina, is placed between the porous gasket and the cell stack face at the margins of the negative end plate to the most negative cells to impede ion current flow. The noble metal foil, for instance gold, is electrically coupled to the negative potential of the stack to collect positive ions at a harmless location away from the stack face. Consequently, corrosion products from the stack structure deposit on the foil rather than on the stack face to eliminate electrical shorting of cells at the negative end of the stack.

Katz, Murray (Newington, CT); Schroll, Craig R. (West Hartford, CT)

1985-10-22

162

Stack Characterization System Development and Testing  

SciTech Connect

Oak Ridge National Laboratory, as well as the rest of the U.S. Department of Energy community, has numerous off-gas stacks that need to be decommissioned, demolished, and packaged for disposal. Disposal requires a waste disposition determination phase. Process knowledge typically makes a worst-case scenario decision that may place lower-level waste into a more expensive higher-level waste disposal category. Truly useful radiological and chemical sampling can be problematic on old stacks due to their inherent height and access hazards, and many of these stacks have begun to deteriorate structurally. A remote stack characterization system (SCS) that can manage sample and data collection removes people from the hazards and provides an opportunity for access to difficult to reach internal stack areas. The SCS is a remotely operated articulated radiological data recovery system designed to deploy down into off-gas stacks from the top via crane. The battery-powered SCS is designed to stabilize itself against the stack walls and move various data recovery systems into areas of interest on the inner stack walls. Stabilization is provided by a tripod structure; sensors are mounted in a rotatable bipod underneath the tripod. Sensors include a beta/gamma/alpha detector, a removable contaminant multi-sample automated sampler, and a multi-core remote core drill. Multiple cameras provide remote task viewing, support for sampling, and video documentation of the process. A delay in funding has delayed project delivery somewhat. Therefore, this paper describes the technology and shows fabrication and testing progress to the extent that data is available.

Noakes, Mark W [ORNL; Lind, Randall F [ORNL; Lloyd, Peter D [ORNL; Pin, Francois G [ORNL; Rowe, John C [ORNL

2011-01-01

163

Nature and Magnitude of Aromatic Stacking of Nucleic Acid Bases  

SciTech Connect

This review summarises recent advances in quantum chemical calculations of base-stacking forces in nucleic acids. We explain in detail the very complex relationship between the gas-phase basestacking energies, as revealed by quantum chemical (QM) calculations, and the highly variable roles of these interactions in nucleic acids. This issue is rarely discussed in quantum chemical and physical chemistry literature. We further extensively discuss methods that are available for basestacking studies, complexity of comparison of stacking calculations with gas phase experiments, balance of forces in stacked complexes of nucleic acid bases, and the relation between QM and force field descriptions. We also review all recent calculations on base-stacking systems, including details analysis of the B-DNA stacking. Specific attention is paid to the highest accuracy QM calculations, to the decomposition of the interactions, and development of dispersion-balanced DFT methods. Future prospects of computational studies of base stacking are discussed.

Sponer, Jiri; Riley, Kevin E.; Hobza, Pavel

2008-04-07

164

Measurement of fine particulate and gas-phase species during the New Year's fireworks 2005 in Mainz, Germany  

Microsoft Academic Search

The chemical composition and chemically resolved size distributions of fine aerosol particles were measured at high time resolution (5min) with a time-of-flight aerosol mass spectrometer (TOF-AMS) during the New Year's 2005 fireworks in Mainz, central Germany. In addition, particle number concentrations and trace gas concentrations were measured using a condensation particle counter (CPC) and a proton transfer reaction mass spectrometer

Frank Drewnick; Silke S. Hings; Joachim Curtius; Gunter Eerdekens; Jonathan Williams

2006-01-01

165

Porous coolant tube holder for fuel cell stack  

DOEpatents

A coolant tube holder for a stack of fuel cells is a gas porous sheet of fibrous material adapted to be sandwiched between a cell electrode and a nonporous, gas impervious flat plate which separates adjacent cells. The porous holder has channels in one surface with coolant tubes disposed therein for carrying coolant through the stack. The gas impervious plate is preferably bonded to the opposite surface of the holder, and the channel depth is the full thickness of the holder.

Guthrie, Robin J. (East Hartford, CT)

1981-01-01

166

Stacking faults in magnesium  

SciTech Connect

The energetics of various low-energy intrinsic, extrinsic, and twinlike stacking fault configurations in hexagonal-close-packed magnesium are determined from first-principles calculations. To zeroth-order, the ordering of the energies can be understood in terms of the number of fcc-like planes in the sequence of close-packed planes. However, such a simple model fails to quantitatively reproduce the calculated energies of the faults. We propose a model based on a local bond orientation scheme which reproduces the calculated results and is able to accurately predict the energies of arbitrary stacking sequences. This model has only two independent parameters, the energy of the intrinsic I{sub 1} stacking fault and the energy difference between hcp and fcc Mg. Both energy and entropy considerations suggest that isolated I{sub 1} stacking faults should predominate. {copyright} {ital 1997} {ital The American Physical Society}

Chetty, N. [Department of Physics, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)]|[Department of Physics, University of Natal, Private Bag X01, Scottsville 3209 (South Africa); Weinert, M. [Department of Physics, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)

1997-11-01

167

Impact of alternative fuels on emissions characteristics of a gas turbine engine - part 2: volatile and semivolatile particulate matter emissions.  

PubMed

The work characterizes the changes in volatile and semivolatile PM emissions from a gas turbine engine resulting from burning alternative fuels, specifically gas-to-liquid (GTL), coal-to-liquid (CTL), a blend of Jet A-1 and GTL, biodiesel, and diesel, to the standard Jet A-1. The data presented here, compares the mass spectral fingerprints of the different fuels as measured by the Aerodyne high resolution time-of-flight aerosol mass spectrometer. There were three sample points, two at the exhaust exit plane with dilution added at different locations and another probe located 10 m downstream. For emissions measured at the downstream probe when the engine was operating at high power, all fuels produced chemically similar organic PM, dominated by C(x)H(y) fragments, suggesting the presence of long chain alkanes. The second largest contribution came from C(x)H(y)O(z) fragments, possibly from carbonyls or alcohols. For the nondiesel fuels, the highest loadings of organic PM were from the downstream probe at high power. Conversely, the diesel based fuels produced more organic material at low power from one of the exit plane probes. Differences in the composition of the PM for certain fuels were observed as the engine power decreased to idle and the measurements were made closer to the exit plane. PMID:22913312

Williams, Paul I; Allan, James D; Lobo, Prem; Coe, Hugh; Christie, Simon; Wilson, Christopher; Hagen, Donald; Whitefield, Philip; Raper, David; Rye, Lucas

2012-09-13

168

Impact of alternative fuels on emissions characteristics of a gas turbine engine - part 1: gaseous and particulate matter emissions.  

PubMed

Growing concern over emissions from increased airport operations has resulted in a need to assess the impact of aviation related activities on local air quality in and around airports, and to develop strategies to mitigate these effects. One such strategy being investigated is the use of alternative fuels in aircraft engines and auxiliary power units (APUs) as a means to diversify fuel supplies and reduce emissions. This paper summarizes the results of a study to characterize the emissions of an APU, a small gas turbine engine, burning conventional Jet A-1, a fully synthetic jet fuel, and other alternative fuels with varying compositions. Gas phase emissions were measured at the engine exit plane while PM emissions were recorded at the exit plane as well as 10 m downstream of the engine. Five percent reduction in NO(x) emissions and 5-10% reduction in CO emissions were observed for the alternative fuels. Significant reductions in PM emissions at the engine exit plane were achieved with the alternative fuels. However, as the exhaust plume expanded and cooled, organic species were found to condense on the PM. This increase in organic PM elevated the PM mass but had little impact on PM number. PMID:22913288

Lobo, Prem; Rye, Lucas; Williams, Paul I; Christie, Simon; Uryga-Bugajska, Ilona; Wilson, Christopher W; Hagen, Donald E; Whitefield, Philip D; Blakey, Simon; Coe, Hugh; Raper, David; Pourkashanian, Mohamed

2012-09-17

169

Carbon nanotubes coated by carbon nanoparticles of turbostratic stacked graphenes  

Microsoft Academic Search

Carbon nanotubes (CNTs) decorated by a high density of carbon nanoparticles of turbostratic graphene stacks have been fabricated by low energy hydrocarbon ion deposition at 700°C. Transmission and scanning electron microscopy show that the carbon particles of turbostratic graphene stacks extend from the nanotube surface. The diameter of CNTs decreases with the increasing percentage of hydrogen in the gas phase.

Qintao Li; Zhichun Ni; Jinlong Gong; Dezhang Zhu; Zhiyuan Zhu

2008-01-01

170

76. General view looking east showing Rust Co. boiler stacks ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

76. General view looking east showing Rust Co. boiler stacks at left, Babcock & Wilcox type boiler stacks at right, Dovel horizontal gas washer in foreground, and No. 1 Furnace in distance. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

171

Emissions of SO2, NOx and particulates from a pipe manufacturing plant and prediction of impact on air quality.  

PubMed

Integrated pipe manufacturing industry is operation intensive and has significant air pollution potential especially when it is equipped with a captive power production facility. Emissions of SO(2), NO(x), and particulate matter (PM) were estimated from the stationary sources in a state-of-the-art pipe manufacturing plant in India. Major air polluting units like blast furnace, ductile iron spun pipe facility, and captive power production facility were selected for stack gas monitoring. Subsequently, ambient air quality modeling was undertaken to predict ground-level concentrations of the selected air pollutants using Industrial Source Complex (ISC 3) model. Emissions of SO(2), NO(x), and particulate matter from the stationary sources in selected facilities ranged from 0.02 to 16.5, 0.03 to 93.3, and 0.09 to 48.3 kg h(-1), respectively. Concentration of SO(2) and NO(x) in stack gas of 1,180-kVA (1 KW = 1.25 kVA) diesel generator exceeded the upper safe limits prescribed by the State Pollution Control Board, while concentrations of the same from all other units were within the prescribed limits. Particulate emission was highest from the barrel grinding operation, where grinding of the manufactured pipes is undertaken for giving the final shape. Particulate emission was also high from dedusting operation where coal dust is handled. Air quality modeling indicated that maximum possible ground-level concentration of PM, SO(2), and NO(x) were to the tune of 13, 3, and 18 microg/m(3), respectively, which are within the prescribed limits for ambient air given by the Central Pollution Control Board. PMID:19888663

Bhanarkar, A D; Majumdar, Deepanjan; Nema, P; George, K V

2009-11-04

172

Particulate residence times  

Microsoft Academic Search

Examination of suspended particulate concentration data from a year-long, regional air-quality study of a portion of the Great Lakes area revealed that depletion of particulates occurred during extended periods of travel over water surfaces. Based on particulate concentrations and meteorological measurements, residence times of background regional particulate matter were found to be between 5 and 16 h in the region.

D. M. Whelpdale

1974-01-01

173

A ?-stacked phenylacetylene dimer.  

PubMed

The structure of the phenylacetylene-dimer has been elucidated using IR-UV double resonance spectroscopy in combination with high level ab initio calculations at the CCSD(T)/CBS level. The IR spectra in the acetylenic and the aromatic C-H stretching regions indicate that the two phenylacetylene moieties are in identical environments and very similar to the phenylacetylene monomer. Calculated stabilization energies and the free energies at the CCSD(T)/CBS level favor the formation of an anti-parallel ?-stacked structure. The DFT-SAPT energy decomposition analysis points out that the anti-parallel ?-stacked structure maximizes electrostatic as well as the dispersion components of energy. The observed IR spectra are consistent with the anti-parallel ?-stacked structure. PMID:21858279

Maity, Surajit; Patwari, G Naresh; Sedlak, Robert; Hobza, Pavel

2011-08-19

174

Stochastic stacking without filters  

SciTech Connect

The rate of accumulation of antiprotons is a critical factor in the design of p anti p colliders. A design of a system to accumulate higher anti p fluxes is presented here which is an alternative to the schemes used at the CERN AA and in the Fermilab Tevatron I design. Contrary to these stacking schemes, which use a system of notch filters to protect the dense core of antiprotons from the high power of the stack tail stochastic cooling, an eddy current shutter is used to protect the core in the region of the stack tail cooling kicker. Without filters one can have larger cooling bandwidths, better mixing for stochastic cooling, and easier operational criteria for the power amplifiers. In the case considered here a flux of 1.4 x 10/sup 8/ per sec is achieved with a 4 to 8 GHz bandwidth.

Johnson, R.P.; Marriner, J.

1982-12-01

175

Stack filter classifiers  

SciTech Connect

Just as linear models generalize the sample mean and weighted average, weighted order statistic models generalize the sample median and weighted median. This analogy can be continued informally to generalized additive modeels in the case of the mean, and Stack Filters in the case of the median. Both of these model classes have been extensively studied for signal and image processing but it is surprising to find that for pattern classification, their treatment has been significantly one sided. Generalized additive models are now a major tool in pattern classification and many different learning algorithms have been developed to fit model parameters to finite data. However Stack Filters remain largely confined to signal and image processing and learning algorithms for classification are yet to be seen. This paper is a step towards Stack Filter Classifiers and it shows that the approach is interesting from both a theoretical and a practical perspective.

Porter, Reid B [Los Alamos National Laboratory; Hush, Don [Los Alamos National Laboratory

2009-01-01

176

CROSS-STACK OPTICAL CONVOLUTION VELOCIMETER DEVELOPMENT AND EVALUATION OF A BREADBOARD DESIGN  

EPA Science Inventory

A new type of instrument has been designed and evaluated for the measurement of a line average of a stack gas velocity. The light output from a lamp is collimated and projected across the stack. A shadowgraph image of the turbulence in the stack is produced on the far side and th...

177

Typical snead stacks, lower (first) stack level, view facing northwest. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Typical snead stacks, lower (first) stack level, view facing northwest. - Army War College, Fort Lesley J. McNair, entrance on P Street between Third & Fourth Streets Southwest, Washington, District of Columbia, DC

178

GENERAL PERSPECTIVE VIEW OF BOTH FURNACE STACKS LOOKING SOUTHWEST (STACK ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

GENERAL PERSPECTIVE VIEW OF BOTH FURNACE STACKS LOOKING SOUTHWEST (STACK NO. 1 TO LEFT, NO. 2 TO RIGHT) - Greenwood Furnace, East of McAlevy's Fort on State Route 305, McAlevys Fort, Huntingdon County, PA

179

Stacking up the Atmosphere  

NSDL National Science Digital Library

In this hands-on activity, participants learn the characteristics of the five layers of the atmosphere and make illustrations to represent them. They roll the drawings and place them in clear plastic cylinders, and then stack the cylinders to make a model column of the atmosphere.

Youngman, Betsy; Pennycook, Jean; Huffman, Louise; Dahlman, Luann; Nebraska, Andrill- U.

180

Issues in Stacked Generalization  

Microsoft Academic Search

Stacked generalization is a general method of using a high-level model to combine lower-level models to achieve greater predictive accuracy. In this paper we address two crucial issues which have been considered to be a `black art\\

Kai Ming Ting; Ian H. Witten

1999-01-01

181

GENERAL PERSPECTIVE VIEW OF BOTH FURNACE STACKS LOOKING NORTHEAST (STACK ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

GENERAL PERSPECTIVE VIEW OF BOTH FURNACE STACKS LOOKING NORTHEAST (STACK NO. 2 TO LEFT, REMAINS OF NO. 1 AT CENTER RIGHT) - Greenwood Furnace, Stack No. 2, East of McAlevy's Fort on State Route 305, McAlevys Fort, Huntingdon County, PA

182

Reversejet scrubber for control of fine particulates  

SciTech Connect

Reports that the pressure drop of this reversing jet spray system, which removes particulates from hot process and exhaust gas streams, is half of the gas-phase pressure drop of conventional wet scrubbers. The Reverse jet scrubber uses multiple reversing scrub liquor sprays to achieve the gasliquid interfacial area, residence time, and high differential velocities required for efficient heat and mass transfer, and particulate collection. Analysis of pilot-scale particulate removal data, obtained with the air-water-dioctyl phthalate (DOP) mist system at ambient conditions, permits a generalized Reversejet design procedure to be developed. This design procedure, verified with field tests involving cleanup of hot exhaust gases from oil-fired burners, provides a sound basis for the specification of commercial-scale equipment. The scrubber is compact, and nonfouling due to its open structure design. Half of the scrubber power input is applied to the gas phase, and half to the liquid phase. Describes a particulate collection model, based on single-spray droplet collection efficiencies. Relevant parameters in this model are: the maximum stable spray droplet size; the relative velocity between the spray droplets and the gas; the size of particulate to be removed; the jet turnaround length; and the effective, volumetric gas-liquid contact area. The pilot-plant scrubber on oil-fired combustion gases obtained removal efficiencies of up to 78%. Proposes a preliminary design for cleanup of hot fuel gas from a fluidized-bed-type coal gasifier.

Holmes, T.L.; DeGarmo, J.L.; Meyer, C.F.

1983-02-01

183

Thermoacoustics with idealized heat exchangers and no stack.  

PubMed

A model is developed for thermoacoustic devices that have neither stack nor regenerator. These "no-stack" devices have heat exchangers placed close together in an acoustic standing wave of sufficient amplitude to allow individual parcels of gas to enter both exchangers. The assumption of perfect heat transfer in the exchangers facilitates the construction of a simple model similar to the "moving parcel picture" that is used as a first approach to stack-based engines and refrigerators. The model no-stack cycle is shown to have potentially greater inviscid efficiency than a comparable stack model. However, losses from flow through the heat exchangers and on the walls of the enclosure are greater than those in a stack-based device due to the increased acoustic pressure amplitude. Estimates of these losses in refrigerators are used to compare the possible efficiencies of real refrigerators made with or without a stack. The model predicts that no-stack refrigerators can exceed stack-based refrigerators in efficiency, but only for particular enclosure geometries. PMID:12083198

Wakeland, Ray Scott; Keolian, Robert M

2002-06-01

184

Analysis of palladium concentrations in airborne particulate matter with reductive co-precipitation, He collision gas, and ID-ICP-Q-MS.  

PubMed

The concentration of platinum group elements (PGE) in the environment has increased significantly in the last 20 years mainly due to their use as catalysts in automotive catalytic converters. The quantitation of these metals in different environmental compartments is, however, challenging due to their very low concentrations and the presence of interfering matrix constituents when inductively coupled plasma-mass spectrometry (ICP-MS) is used for analysis. Previously, the research focus was on the analysis of platinum (Pt) and rhodium (Rh). However, due to the increasing use of palladium (Pd) in automotive catalytic converters, quantitation of this element in airborne particulate matter (PM) is also needed. Compared to Pt and Rh, measurements of Pd using ICP-MS are plagued by greater molecular interferences arising from elements such as copper (Cu), zinc (Zn) strontium (Sr), yttrium (Y), and zirconium (Zr). The aim of this study was to evaluate the applicability of reductive co-precipitation procedures using both mercury (Hg) and tellurium (Te) for the pre-concentration of Pd from airborne PM. Furthermore, helium (He) was tested as a collision gas for isotope dilution-inductively coupled plasma-quadrupole-mass spectrometry (ID-ICP-Q-MS) to measure Pd in the Hg and Te precipitates. Airborne PM samples (PM10) were collected from Neuglobsow (Brandenburg, north-eastern Germany) and Deuselbach (Rhineland-Palatinate, south-western Germany), considered to represent background levels, and from the city Frankfurt am Main (Hesse, Germany), a high-traffic area. Samples were first digested with aqua regia in a high-pressure asher (HPA) at 320 degrees C and 130 bar prior to the application of reductive co-precipitation procedures. The method was validated with road dust reference material BCR-723 and the CANMET-CCRMP reference material TDB-1 and WPR-1. In airborne PM collected at the background areas Neuglobsow and Deuselbach, Pd was detected with median concentrations values of 0.5 and 0.6 pg/m3, respectively. Much higher median concentration values of 14.8 pg Pd/m3 (detection limit = 0.01 pg Pd/m3) were detected in samples collected in the city of Frankfurt am Main. Results have shown that Hg co-precipitation depletes the concentrations of interfering matrix constituents by at least one order of magnitude more, compared to Te co-precipitation, making it a more effective method for the isolation and pre-enrichment of Pd from airborne PM prior to analysis. The use of a He gas flow of 120 ml/min in the plasma further minimized interferences, particularly those arising from CuAr+, YO+, and ZrO+ during the determination of Pd. The results demonstrate that Hg co-precipitation and the use of He collision gas, in combination with isotope dilution, are highly effective methods for the quantitation of Pd in airborne PM using ICP-MS. PMID:19784830

Alsenz, H; Zereini, F; Wiseman, C L S; Püttmann, W

2009-11-01

185

Retort Water Particulates.  

National Technical Information Service (NTIS)

Particulates were collected from 11 retort waters and their chemical composition and morphology studied using x-ray fluorescence spectrometry, x-ray diffraction and scanning electron microscopy. This work indicates that the particulate fraction of retort ...

J. P. Fox

1979-01-01

186

Cometary Particulate Analyzer.  

National Technical Information Service (NTIS)

A concept for determining the relative abundance of elements contained in cometary particulates was evaluated. The technique utilizes a short, high intensity burst of laser radiation to vaporize and ionize collected particulate material. Ions extracted fr...

D. J. Miller J. F. Friichtenicht N. G. Utterback

1979-01-01

187

Stack inspection: theory and variants  

Microsoft Academic Search

Stack inspection is a security mechanism implemented in runtimes such as the JVM and the CLR to accommodate components with diverse levels of trust. Although stack inspection enables the fine-grained expression of access control policies, it has rather a complex and subtle semantics. We present a formal semantics and an equational theory to explain how stack inspection affects program behaviour

Cédric Fournet; Andrew D. Gordon

2002-01-01

188

30 CFR Particulate - Underground Only  

Code of Federal Regulations, 2010 CFR

...Only Particulate Diesel Particulate Matter Mineral Resources MINE SAFETY AND...Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57...Apr. 3, 2006] Diesel Particulate MatterâUnderground Only Source: 66...

2010-07-01

189

Diesel particulate control  

Microsoft Academic Search

Diesel particulates, because of their chemical composition and extremely small size, have raised health and welfare issues. Health experts have expressed concern that they contribute to or aggravate chronic lung diseases such as asthma, bronchitis and emphysema, and there is the lingering issue about the potential cancer risk from exposure to diesel particulate. Diesel particulates impair visibility, soil buildings, contribute

Bertelsen

1988-01-01

190

Combustor for fine particulate coal  

DOEpatents

A particulate coal combustor with two combustion chambers is provided. The first combustion chamber is toroidal; air and fuel are injected, mixed, circulated and partially combusted. The air to fuel ratio is controlled to avoid production of soot or nitrogen oxides. The mixture is then moved to a second combustion chamber by injection of additional air where combustion is completed and ash removed. Temperature in the second chamber is controlled by cooling and gas mixing. The clean stream of hot gas is then delivered to a prime mover. 4 figs.

Carlson, L.W.

1988-01-26

191

Combustor for fine particulate coal  

DOEpatents

A particulate coal combustor with two combustion chambers is provided. The first combustion chamber is toroidal; air and fuel are injected, mixed, circulated and partially combusted. The air to fuel ratio is controlled to avoid production of soot or nitrogen oxides. The mixture is then moved to a second combustion chamber by injection of additional air where combustion is completed and ash removed. Temperature in the second chamber is controlled by cooling and gas mixing. The clean stream of hot gas is then delivered to a prime mover. 4 figs.

Carlson, L.W.

1988-11-08

192

The influence of humidity, temperature and other variables on the electric charging characteristics of particulate aluminium hydroxide in gas–solid pipeline flows  

Microsoft Academic Search

This paper reports work undertaken to explore the influence of air relative humidity, temperature and particle size on the electric charging characteristics of particulate aluminium hydroxide during transport in a pneumatic pipeline. Limited data with regard to the influence of flow suspension density and velocity is also reported. Values of air relative humidity from 35% to 50% and temperatures of

S. R. Woodhead; D. I. Armour-Chélu

2003-01-01

193

Development of internal reforming carbonate fuel cell stack technology  

SciTech Connect

Activities under this contract focused on the development of a coal-fueled carbonate fuel cell system design and the stack technology consistent with the system design. The overall contract effort was divided into three phases. The first phase, completed in January 1988, provided carbonate fuel cell component scale-up from the 1ft{sup 2} size to the commercial 4ft{sup 2} size. The second phase of the program provided the coal-fueled carbonate fuel cell system (CGCFC) conceptual design and carried out initial research and development needs of the CGCFC system. The final phase of the program emphasized stack height scale-up and improvement of stack life. The results of the second and third phases are included in this report. Program activities under Phase 2 and 3 were designed to address several key development areas to prepare the carbonate fuel cell system, particularly the coal-fueled CFC power plant, for commercialization in late 1990's. The issues addressed include: Coal-Gas Related Considerations; Cell and Stack Technology Improvement; Carbonate Fuel Cell Stack Design Development; Stack Tests for Design Verification; Full-Size Stack Design; Test Facility Development; Carbonate Fuel Cell Stack Cost Assessment; and Coal-Fueled Carbonate Fuel Cell System Design. All the major program objectives in each of the topical areas were successfully achieved. This report is organized along the above-mentioned topical areas. Each topical area has been processed separately for inclusion on the data base.

Farooque, M.

1990-10-01

194

Stacking with dual bootstrap resampling  

NASA Astrophysics Data System (ADS)

A new kind of stacking scheme, based on the hypothesis testing of signal significance and coherence, is proposed. The significance of stacked data is evaluated by running two kinds of bootstrap resampling, one for standard bootstrap and the other for preparing noise stacks by scrambling relative time-shifts between traces. This dual bootstrap procedure allows us to formulate a two-sample problem for signal significance, which is shown to be more reliable than standard bootstrap estimates. The statistics of noise obtained in dual bootstrap resampling is also used when assessing the coherence of data with the empirical distribution function, in which the effect of noise is deconvolved by rescaling. Unlike conventional non-linear stacks such as Nth-root stack and phase-weighted stack, the new stack can recover signals even when the signal-to-noise ratio (S/N) is low, and compared to simple linear stack, the number of traces required for unambiguous signal detection is reduced by up to two orders of magnitude. The new scheme, called dual bootstrap stack, could facilitate a range of geophysical data processing when trying to detect subtle signals by stacking low S/N data.

Korenaga, Jun

2013-10-01

195

Stacked waveguide image slicer.  

NASA Astrophysics Data System (ADS)

A novel image slicer has been developed which is composed of stacked thin-glass plates. Each glass plate works as optical waveguides and the glass plates are prepared so that the beam-exit portions line up linearly in a step-like form. The glass plates are optically polished and are glued with STYCAST that works as a clad for the waveguide. By choosing the pair of refractive indices of the core and clad appropriately, this slicer can be used in an optical system with a F/ratio as fast as 3.

Suto, H.; Takami, H.

196

Comparison of Particulate Collection in Probes and on Filters  

SciTech Connect

Major radionuclide emissions from the Department of Energy's Y-12 National Security Complex are nuclides of uranium which are emitted as a particulate. The radionuclide NESHAP regulation requires stack sampling to be conducted in accordance with ANST Standard N13.1, 1969. Appendix B of this standard requires in every case where sampling delivery lines are used that an evaluation should be made of deposition in these lines. A number of Y-12 Complex stacks are fitted with continuous samplers which draw particulate laden air through a probe and across a sample filter. One approach to evaluate line loss as required by the ANSI standard is to establish a representative factor that is used for all subsequent sampling efforts. Another approach is to conduct a routine probe wash procedure on an ongoing basis to account for line losses. In 1991, Y-12 National Security Complex personnel began routine probe washes as part of their sample collection procedure. Since then, 50-80 stacks have been sampled on a near continuous basis and probe washes have been conducted quarterly. Particulate collection in probes versus particulate collection on filters is recorded as a probe factor and probe factor trends for a 10-year period are available.

Eaton, J.M.; Humphreys, M.P.

2001-06-14

197

Particulate Matter and Carbon Monoxide in Highland Guatemala: Indoor and Outdoor Levels from Traditional and Improved Wood Stoves and Gas Stoves  

Microsoft Academic Search

Area 22-h average carbon monoxide (CO), total sus- pended particulates (TSP), particles less than 10 mm in diameter (PM10), and particles less than 2.5 mm in diameter (PM2.5) meas- urements were made in three test homes of highland rural Guate- mala in kitchens, bedrooms, and outdoors on a longitudinal basis, i.e. before and after introduction of potential exposure-re- ducing interventions.

L. P. NAEHER; B. P. LEADERER; K. R. Smith

2000-01-01

198

Progress report and technology status development of an EG and G Berthold LB-150 alpha/beta particulate monitor for use on the East Tennessee Technology Park Toxic Substances Control Act Incinerator  

SciTech Connect

The purpose of this project was to modify and evaluate a commercially available EG and G Berthold LB-150 alpha-beta radionuclide particulate monitor for the high-temperature and moisture-saturation conditions of the East Tennessee Technology Park (formerly K-25 Site) Toxic Substances Control Act (TSCA) Incinerator stack. The monitor was originally outfitted for operation at gas temperatures of 150 F on the defunct Los Alamos National Laboratory (LANL) controlled air incinerator, and the objective was to widen its operating envelope. A laboratory apparatus was constructed that simulated the effects of water-saturated air at the TSCA Incinerator stack-gas temperatures, 183 F. An instrumented set of heat exchangers was constructed to then condition the gas so that the radionuclide monitor could be operated without condensation. Data were collected under the conditions of the elevated temperatures and humidities and are reported herein, and design considerations of the apparatus are provided. The heat exchangers and humidification equipment performed as designed, the Mylar film held, and the instrument suffered no ill effects. However, for reasons as yet undetermined, the sensitivity of the radionuclide detection diminishes as the gas temperature is elevated, whether the gas is humidified or not. The manufacturer has had no experience with (a) the operation of the monitor under these conditions and (b) any commercial market that might exist for an instrument that operates under these conditions. The monitor was not installed into the radiologically contaminated environment of the TSCA Incinerator stack pending resolution of this technical issue.

Shor, J.T.; Singh, S.P.N. [Oak Ridge National Lab., TN (United States). Chemical Technology Div.; Gibson, L.V. Jr. [East Tennessee Technology Park, Oak Ridge, TN (United States). ASO Customer Services Div.

1998-06-01

199

Stacked insulator induction accelerator gaps  

SciTech Connect

Stacked insulators, with alternating layers of insulating material and conducting film, have been shown to support high surface electrical field stresses. We have investigated the application of the stacked insulator technology to the design of induction accelerator modules for the Relativistic-Klystron Two-Beam Accelerator program. The rf properties of the accelerating gaps using stacked insulators, particularly the impedance at frequencies above the beam pipe cutoff frequency, are investigated. Low impedance is critical for Relativistic-Klystron Two-Beam Accelerator applications where a high current, bunched beam is trsnsported through many accelerating gaps. An induction accelerator module designs using a stacked insulator is presented.

Houck, T.I.; Westenskow, G.A.; Kim, J.S.; Eylon, S.; Henestroza, E.; Yu, S.S.; Vanecek, D.

1997-05-01

200

A laboratory comparison of two methods of characterizing exhaust stack emissions. Final report  

Microsoft Academic Search

Concern for the environment and public health, and compliance with DOE and EPA regulations require that representative sampling be conducted on exhaust stacks that emit radioactive materials. In order to design and install particulate samplers, EPA Regulation 40CFR61, Subpart H (NESHAP) specifies that particle concentration profiles be determined, in addition to velocity profiles, at the sampling cross section of all

C. Fairchild; J. LaBauve; R. Kissane; C. Ortiz

1995-01-01

201

Study of stack emissions by combination of Lidar and correlation spectrometer  

Microsoft Academic Search

Summary  For remote sensing of localized masses of atmospheric pollutants such as stack plumes interesting information can be gained by a joint application of different techniques. This paper deals with the combination of Lidar and absorption correlation spectrometry, with their respective abilities to detect particulate matter and specific molecular components. By simultaneous monitoring of a plume and proper exploitation of the

P. Camagni; E. De Blust; C. Koechler; R. Michelon; A. Pedrini; M. De Groot; S. Sandroni

1981-01-01

202

New Stack Effluent Monitoring System at the Risoe Hot Cell Plant.  

National Technical Information Service (NTIS)

This report describes a new stack effluent monitoring system that has been installed at the Hot Cell facility. It is an integrating iodine/particulate system consisting of a gamma -shielded flow house in which a continous air sample from the ventilation c...

L. Boetter-Jensen P. Hedemann Jensen B. Lauridsen

1984-01-01

203

Stacking energies in DNA.  

PubMed

Variations in base mono- and dipoles result in variations in stacking energies for the 10 unique neighbor pairs in DNA. Stacking energies for pair M on N, expressed as TMN, were derived by matrix decomposition of a large set of linear algebraic expressions relating the measured Tm for subtransitions emanating from large polymeric DNAs, and the fractional neighbor frequencies, fMN, for the domains responsible for the transitions, Tm = sigma fMNTMN. Tm were determined for subtransitions that dissociate in approximately all-or-none fashion in high resolution melting profiles of partially deleted and recombinant forms of pBR322 DNA. Three different analytical maneuvers were undertaken to resolve subtransitions: site-specific cleavage of domains; deletion of domains; and addition of domains. Three dozen domains of widely divergent, quasi-random neighbor frequencies were identified and assigned, resulting in a unique set of values for TMN with standard deviation, sigma = +/- 0.23 degree C. The average difference between calculated and experimental Tm for domains is only +/- 0.17 degree C, indicating that the thermodynamic properties of these domains are not in any way unusual. Assuming delta S to be constant for all pairs, the corresponding delta HMN are found to have a precision of +/- 10 calories.mol-1 and an accuracy of +/- 606 calories.mol-1. TMN used to calculate melting curves by statistical mechanical analysis of sequences of the different plasmid specimens in this study were in quantitative agreement with observed curves for most sequences. These TMN differ significantly from those determined previously and also correlate poorly with values determined by quantum chemical analysis. Stabilities of neighbor pairs, expressed as the difference in free energy between that for a given pair (MN) and that for the average of like pairs (M, N), depend on the relationship of stacked purines and pyrimidines as follows. delta delta Gpu-py(-466 cal) greater than delta delta Gpu-pu(+52 cal) greater than delta delta Gpy-pu(+335 cal) Differences between experimental Tm and Tm calculated with TMN for the isolated neighbor pairs in the B-conformation are useful in the identification of altered structures and unusual modes of dissociation of helixes. A significantly higher Tm is observed for the highly biased repeated sequence synthetic helixes dA.dT, d(AGC).d(GCT), and d(GAT).d(ATC), reflecting auxiliary sources of stability such as bifurcated hydrogen bonds and/or altered structures for these helixes. PMID:1869547

Delcourt, S G; Blake, R D

1991-08-15

204

FAN HOUSE AND STACK NEARLY COMPLETE. CAMERA FACES SOUTHWEST. STACK ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FAN HOUSE AND STACK NEARLY COMPLETE. CAMERA FACES SOUTHWEST. STACK SHOWS MARKS OF CONCRETE LIFT FORMS. INL NEGATIVE NO. 3381. Unknown Photographer, 9/28/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

205

SOFC cells and stacks for complex fuels  

SciTech Connect

Reformed hydrocarbon and coal (syngas) fuels present an opportunity to integrate solid oxide fuel cells into the existing fuel infrastructure. However, these fuels often contain impurities or additives that may lead to cell degradation through sulfur poisoning or coking. Achieving high performance and sulfur tolerance in SOFCs operating on these fuels would simplify system balance of plant and sequestration of anode tail gas. NexTech Materials, Ltd., has developed a suite of materials and components (cells, seals, interconnects) designed for operation in sulfur-containing syngas fuels. These materials and component technologies have been integrated into an SOFC stack for testing on simulated propane, logistic fuel reformates and coal syngas. Details of the technical approach, cell and stack performance is reported.

Edward M. Sabolsky; Matthew Seabaugh; Katarzyna Sabolsky; Sergio A. Ibanez; Zhimin Zhong

2007-07-01

206

Removal of SOx, NOx, and particulate from combusted carbonaceous fuels  

Microsoft Academic Search

The invention is a method for removing sulfur oxides, nitrogen oxides and particulate from the products of combusted carbonaceous fuels. Sulfur oxides, nitrogen oxides and particulate are currently discharged to the atmosphere as flue gas in quantities highly detrimental to the environment. Potassium compounds, as are found in agricultural grade potash, are dispersed throughout the combustion products at the exit

Dayen

1985-01-01

207

Spherical Torus Center Stack Design  

SciTech Connect

The low aspect ratio spherical torus (ST) configuration requires that the center stack design be optimized within a limited available space, using materials within their established allowables. This paper presents center stack design methods developed by the National Spherical Torus Experiment (NSTX) Project Team during the initial design of NSTX, and more recently for studies of a possible next-step ST (NSST) device.

C. Neumeyer; P. Heitzenroeder; C. Kessel; M. Ono; M. Peng; J. Schmidt; R. Woolley; I. Zatz

2002-01-18

208

Spherical torus center stack design  

SciTech Connect

The low aspect ratio spherical torus (ST) configuration requires that the center stack design be optimized within a limited available space, using materials within their established allowables. This paper presents certer stack design methods developed by the National Spherical Torus Experiment (NSTX) Project Team during the initial design of NSTX, and more recently for studies of a possible next step ST (NSST) device.

Neumeyer, C. L. [Princeton Plasma Physics Laboratory (PPPL); Peng, Yueng Kay Martin [ORNL

2002-01-01

209

One-way stack automata  

Microsoft Academic Search

A number of operations which either preserve sets accepted by one-way stack automata or preserve sets accepted by deterministic one-way stack automata are presented. For example, sequential transduction preserves the former; set complementation, the latter. Several solvability questions are also considered.

Seymour Ginsburg; Sheila A. Greibach; Michael A. Harrison

1967-01-01

210

Die Stacking (3D) Microarchitecture  

Microsoft Academic Search

D die stacking is an exciting new technology that in- creases transistor density by vertically integrating two or more die with a dense, high-speed interface. The result of 3D die stacking is a significant reduction of interconnect both within a die and across dies in a system. For instance, blocks within a microprocessor can be placed vertically on multiple die

Bryan Black; Murali Annavaram; Ned Brekelbaum; John Devale; Lei Jiang; Gabriel H. Loh; Don McCauley; Pat Morrow; Donald W. Nelson; Daniel Pantuso; Paul Reed; Jeff Rupley; Sadasivan Shankar; John Paul Shen; Clair Webb

2006-01-01

211

Particulate Measurements and Emissions Characterization of Alternative Fuel Vehicle Exhaust  

SciTech Connect

The objective of this project was to measure and characterize particulate emissions from light-duty alternative fuel vehicles (AFVs) and equivalent gasoline-fueled vehicles. The project included emission testing of a fleet of 129 gasoline-fueled vehicles and 19 diesel vehicles. Particulate measurements were obtained over Federal Test Procedure and US06 cycles. Chemical characterization of the exhaust particulate was also performed. Overall, the particulate emissions from modern technology compressed natural gas and methanol vehicles were low, but were still comparable to those of similar technology gasoline vehicles.

Durbin, T. D.; Truex, T. J.; Norbeck, J. M. (Center for Environmental Research and Technology College of Engineering, University of California - Riverside, California)

1998-11-19

212

Pitch based foam with particulate  

DOEpatents

A thermally conductive, pitch based foam composite having a particulate content. The particulate alters the mechanical characteristics of the foam without severely degrading the foam thermal conductivity. The composite is formed by mixing the particulate with pitch prior to foaming.

Klett, James W. (Knoxville, TN)

2001-01-01

213

Particulate Air Pollution: The Particulars  

ERIC Educational Resources Information Center

|Describes some of the causes and consequences of particulate air pollution. Outlines the experimental procedures for measuring the amount of particulate materials that settles from the air and for observing the nature of particulate air pollution. (JR)|

Murphy, James E.

1973-01-01

214

Airborne particulate discriminator  

DOEpatents

A method and apparatus for rapid and accurate detection and discrimination of biological, radiological, and chemical particles in air. A suspect aerosol of the target particulates is treated with a taggant aerosol of ultrafine particulates. Coagulation of the taggant and target particles causes a change in fluorescent properties of the cloud, providing an indication of the presence of the target.

Creek, Kathryn Louise (San Diego, CA); Castro, Alonso (Santa Fe, NM); Gray, Perry Clayton (Los Alamos, NM)

2009-08-11

215

ADVANCED HYBRID PARTICULATE COLLECTOR  

Microsoft Academic Search

A new concept in particulate control, called an advanced hybrid particulate collector (AHPC), is being developed under funding from the U.S. Department of Energy. The AHPC combines the best features of electrostatic precipitators (ESPs) and baghouses in an entirely novel manner. The AHPC concept combines fabric filtration and electrostatic precipitation in the same housing, providing major synergism between the two

Ye Zhuang; Stanley J. Miller; Michelle R. Olderbak; Rich Gebert

2001-01-01

216

Ceramic Composite for Diesel Particulate Filter (DPF)  

Microsoft Academic Search

Diesel engine is the most efficient power plant among all known types of internal combustion engines. The Diesel Engine is major candidate to become the power plant of the future. Environmental benefits of Diesel such as low green house gas emissions are balanced by growing concern with emission of Nitrogen oxide (NOx) and Diesel Particulates (PM). The concern over Diesel

N. V. Deshpande; S. C. Kongre; P. N. Deshpande

217

Process for regenerating fluidizable particulate cracking catalysts  

Microsoft Academic Search

A process and apparatus for regenerating fluidizable particulate cracking catalysts wherein a mixture of spent catalyst particles contaminated with carbonaceous deposits from a catalytic cracker and sufficient hot regenerated catalyst particles to bring the temperature of the mixture to the minimum temperature at which rapid oxidation of the carbonaceous deposits will be induced, are entrained in a high velocity gas

Mayes

1981-01-01

218

Pulse combustion drying apparatus for particulate materials  

Microsoft Academic Search

This patent describes a pulse jet combustion apparatus for the drying of particulate material of the type having: a combustion chamber having an air entry end, an exhaust end and a common longitudinal axis therebetween, an air inlet conduit coaxially connected to the air entry and thereof, a primary exhaust gas conduit coaxially connected to the exhaust end thereof and,

R. R. Gray; V. M. Marguth

1987-01-01

219

Impact assessment of respirable suspended particulate matter from diesel generator sets used for pumping station.  

PubMed

Prediction of respirable suspended particulate matter impacts of diesel generator sets used for pumping station has been made using meteorological data, information on stack characteristics and emission rate, baseline ambient particulate matter and Industrial Source Complex Short Term (ISCST-3) model. It is observed that particulate matter emission from pumping station-S workplace diesel generator sets ranged from 2.4 to 436.5 mg Nm?³ and while at pumping station-C, it ranged from 23.2 to 186.5 mg Nm?³. The predicted and ambient respirable suspended particulate matter concentrations are below the national air quality standard for respirable suspended particulate matter in a mixed industrial area. Metals contents in respirable suspended particulate matter indicate the origin of crustal and mobile sources. Therefore, the impact of diesel generator sets used for pumping of crude oil on local air quality would be acceptable. PMID:20700577

Talwar, B; Pipalatkar, P; Gajghate, D G; Nema, P

2010-08-11

220

Theoretical solutions for particulate scintillation monitors  

NASA Astrophysics Data System (ADS)

Theoretical analysis for recently developed particulate scintillation monitoring technique is presented. The technique makes use of a light beam passing through a stack to the opposite detector. The detector measures not only the average light intensity, but also the temporal variation in the light intensity, which is different from conventional opacity systems. The significant advantage of scintillation monitors is their insensitivity to lens contamination. However, until now theories relevant to the technique have not been found in the literature. In this article, it is first assumed that the number of particles in a light beam passing through stack airflow is a Poisson random variable. Then, by use of Mie's theory and stochastic process theory, a mathematical model for output light intensity, the mathematical expectation and the variance of output light intensity are derived. Finally, an equation for calculating particulate mass concentration is obtained. Theoretical analysis shows that scintillation monitors are insensitive to lens contamination but dependent on particle size distribution. Experiments verified the theoretical results.

Chen, Anshi; Hao, Jiming; Zhou, Zhongping; Zu, Jing

1999-08-01

221

Formation of soot particulates in the combustion chamber of a precombustion chamber type diesel engine  

Microsoft Academic Search

To clarify the formation processes of soot particulates in the combustion chamber, we sampled the gas during combustion in a precombustion chamber and a main chamber using an electromagnetic sampling valve, and made a gas analysis by gas chromatography, examined the soot concentration, and size distribution and dispersion of soot particulates with a transmission electron microscope. The following results were

Y. Fujiwara; S. Fukazawa; S. Tosaka; T. Murayama

1984-01-01

222

40 CFR 86.1343-88 - Calculations; particulate exhaust emissions.  

Code of Federal Regulations, 2010 CFR

...sampled by background particulate sampler, cubic feet. (ii) Pib = Pressure elevation above ambient measured at the inlet...most gas meters or flow instruments with unrestricted discharge, Pib is negligible and can be assumed = 0.) (iii) Tib...

2009-07-01

223

40 CFR 86.1343-88 - Calculations; particulate exhaust emissions.  

Code of Federal Regulations, 2010 CFR

...sampled by background particulate sampler, cubic feet. (ii) Pib = Pressure elevation above ambient measured at the inlet...most gas meters or flow instruments with unrestricted discharge, Pib is negligible and can be assumed = 0.) (iii) Tib...

2010-07-01

224

High Efficiency Particulate Removal with Sintered Metal Filters.  

National Technical Information Service (NTIS)

Because of their particle removal efficiencies and durability, sintered metal filters have been chosen for high efficiency particulate air (HEPA) filter protection in the off-gas treatment system for the proposed Idaho National Engineering Laboratory Tran...

B. E. Kirstein W. J. Paplawsky D. T. Pence T. G. Hedahl

1981-01-01

225

Size distribution and chemical composition of metalliferous stack emissions in the San Roque petroleum refinery complex, southern Spain  

Microsoft Academic Search

We demonstrate that there is great variation in the size range and chemical composition of metalliferous particulate matter (PM) present within petrochemical complex chimney stacks. Cascade impactor PM samples from seven size ranges (17, 14, 5, 2.5, 1.3, 0.67, and 0.33?m) were collected from inside stacks within the San Roque complex which includes the largest oil refinery in Spain. SEM

A. M. Sánchez de la Campa; T. Moreno; J. de la Rosa; A. Alastuey; X. Querol

2011-01-01

226

Results of Self-Absorption Study on the Versapor 3000 Filters for Radioactive Particulate Air Sampling  

SciTech Connect

Since the mid-1980s, Pacific Northwest National Laboratory (PNNL) has used a value of 0.85 as the correction factor for self absorption of activity for particulate radioactive air samples collected from building exhaust for environmental monitoring. This value accounts for activity that cannot be detected by direct counting of alpha and beta particles. Emissions can be degraded or blocked by filter fibers for particles buried in the filter material or by inactive dust particles collected with the radioactive particles. These filters are used for monitoring air emissions from PNNL stacks for radioactive particles. This paper describes an effort to re-evaluate self-absorption effects in particulate radioactive air sample filters (Versapor® 3000, 47 mm diameter) used at PNNL. There were two methods used to characterize the samples. Sixty samples were selected from the archive for acid digestion to compare the radioactivity measured by direct gas-flow proportional counting of filters to the results obtained after acid digestion of the filter and counting again by gas-flow proportional detection. Thirty different sample filters were selected for visible light microscopy to evaluate filter loading and particulate characteristics. Mass-loading effects were also considered. Filter ratios were calculated by dividing the initial counts by the post-digestion counts with the expectation that post-digestion counts would be higher because digestion would expose radioactivity embedded in the filter in addition to that on top of the filter. Contrary to expectations, the post digestion readings were almost always lower than initial readings and averaged approximately half the initial readings for both alpha and beta activity. Before and after digestion readings appeared to be related to each other, but with a low coefficient of determination (R^2) value. The ratios had a wide range of values indicating that this method did not provide sufficient precision to quantify self-absorption effects. The microscopy analysis compares different filter loadings and shows that smaller particle sizes (under 10 micron) can readily be seen on the more lightly loaded filters. At higher loadings, however, the particle size is harder to differentiate. This study provides data on actual stack emission samples showing a range of mass loading conditions and visual evidence of particle size and distribution and also presents the difficulties in quantifying self-absorption effects using actual samples.

Barnett, J. M.; Cullinan, Valerie I.; Barnett, Debra S.; Trang-Le, Truc LT; Bliss, Mary; Greenwood, Lawrence R.; Ballinger, Marcel Y.

2009-02-17

227

Determination of Nickel Species in Stack Emissions from Eight Residual Oil-Fired Utility Steam-Generating Units  

Microsoft Academic Search

XAFS spectroscopy has been used to determine the Ni species in particulate matter collected on quartz thimble filters in the stacks of eight residual (No. 6 fuel) oil-burning electric utility steam-generating units. Proper speciation of nickel in emitted particulate matter is necessary to correctly anticipate potential health risks. Analysis of the spectroscopic data using least-squares linear combination methods and a

F Huggins; K Galbreath; K Eylands; L Van Loon; J Olson; E Zillioux; S Ward; P Lynch; P Chu

2011-01-01

228

40 CFR 86.110-94 - Exhaust gas sampling system; diesel-cycle vehicles, and Otto-cycle vehicles requiring particulate...  

Code of Federal Regulations, 2010 CFR

...petroleum gas-fueled Otto-cycle and petroleum-fueled, natural...petroleum gas-fueled diesel-cycle vehicles, the transfer...shall be sufficient to prevent water condensation. However, the...methanol due to condensation of water in the duct connecting...

2009-07-01

229

40 CFR 86.110-94 - Exhaust gas sampling system; diesel-cycle vehicles, and Otto-cycle vehicles requiring particulate...  

Code of Federal Regulations, 2010 CFR

...petroleum gas-fueled Otto-cycle and petroleum-fueled, natural...petroleum gas-fueled diesel-cycle vehicles, the transfer...shall be sufficient to prevent water condensation. However, the...methanol due to condensation of water in the duct connecting...

2010-07-01

230

Syntheses and characterization of copper(II) carboxylate dimers formed from enantiopure ligands containing a strong ?···? stacking synthon: enantioselective single-crystal to single-crystal gas/solid-mediated transformations.  

PubMed

Tri- and tetrafunctional enantiopure ligands have been prepared from 1,8-naphthalic anhydride and the amino acids L-alanine, D-phenylglycine, and L-asparagine to produce (S)-2-(1,8-naphthalimido)propanoic acid (HL(ala)), (R)-2-(1,8-naphthalimido)-2-phenylacetic acid (HL(phg)), and (S)-4-amino-2-(1,8 naphthalimido)-4-oxobutanoic acid (HL(asn)), respectively. Reactions of L(ala)(-) with copper(II) acetate under a variety of solvent conditions has led to the formation and characterization by X-ray crystallography of three similar copper(II) paddlewheel complexes with different axial ligands, [Cu(2)(L(ala))(4)(THF)(2)] (1), [Cu(2)(L(ala))(4)(HL(ala))] (2), and [Cu(2)(L(ala))(4)(py)(THF)] (3). A similar reaction using THF and L(phg)(-) leads to the formation of [Cu(2)(L(phg))(4)(THF)(2)] (4). With the exception of a disordered component in the structure of 4, the naphthalimide groups in all of these compounds are arranged on the same side of the square, central paddlewheel unit, forming what is known as the chiral crown configuration. A variety of ?···? stacking interactions of the 1,8-naphthalimide groups organize all of these complexes into supramolecular structures. The addition of the amide group functionality in the L(asn)(-) ligand leads to the formation of tetrameric [Cu(4)(L(asn))(8)(py)(MeOH)] (5), where reciprocal axial coordination of one of the amide carbonyl oxygen atoms between two dimers leads to the tetramer. Extensive supramolecular interactions in 5, mainly the ?···? stacking interactions of the 1,8-naphthalimide supramolecular synthon, support an open three-dimensional structure containing large pores filled with solvent. When crystals of [Cu(4)(L(asn))(8)(py)(MeOH)] are exposed to (S)-ethyl lactate vapor, the coordinated methanol molecule is replaced by (S)-ethyl lactate, bonding to the copper ion through the carbonyl oxygen, yielding [Cu(4)(L(asn))(8)(py)((S)-ethyl lactate)] (6) without a loss of crystallinity. With the exception of the replacement of the one axial ligand, the molecular structures of 5 and 6 are very similar. In a similar experiment of 5 with vapors of (R)-ethyl lactate, again a change occurs without a loss of crystallinity, but in this case the (R)-ethyl lactate displaces only slightly more than half of the axial methanol molecules forming [Cu(4)(L(asn))(8)(py){((R)-ethyl lactate)(0.58)(MeOH)(0.42)}] (7). Importantly, in 7, the (R)-ethyl lactate coordinates through the hydroxyl group. When crystals of [Cu(4)(L(asn))(8)(py)(MeOH)] are exposed to vapors of racemic ethyl lactate, the coordinated methanol molecule is displaced without a loss of crystallinity exclusively by (S)-ethyl lactate, yielding a new form of the tetramer [Cu(4)(L(asn))(8)(py)((S)-ethyl lactate)], in which the ethyl lactate in the pocket bonds to the copper(II) ion through the carbonyl oxygen as with 6. Exposure of [Cu(4)(L(asn))(8)(py){((R)-ethyl lactate)(0.58)(MeOH)(0.42)}] to racemic ethyl lactate yields a third form of [Cu(4)(L(asn))(8)(py)((S)-ethyl lactate)], where the three forms of [Cu(4)(L(asn))(8)(py)((S)-ethyl lactate)] have differences in the number of ordered (S)-ethyl lactate molecules located in the interstitial sites. These results demonstrate enantioselective bonding to a metal center in the chiral pocket of both 5 and 7 during single-crystal to single-crystal gas/solid-mediated exchange reactions. PMID:21919476

Reger, Daniel L; Horger, Jacob J; Debreczeni, Agota; Smith, Mark D

2011-09-15

231

Edge states in stacked nanographene  

NASA Astrophysics Data System (ADS)

Nanocarbon materials are investigated intensively. In this paper, the edge-state in nanographene materials with zigzag edges is studied theoretically. In particular, while the inter-layer interactions are considered, we prove that edge states exist at the energy of the Dirac point in the doubly stacked nanographene, and in the case of the infinitely-wide lower layer case. This property applies both for the A-B and A-C stackings.

Harigaya, Kikuo

2012-12-01

232

Particulates and iron cyanide complex removal  

SciTech Connect

A process is described for scrubbing a synthesis gas stream containing residual amounts of iron containing particulate solids and minor amounts of HCN comprising (a) contacting the synthesis gas stream with water in a contact zone and removing the particulate solids from the synthesis gas stream, producing an aqueous mixture containing solids and iron cyanide complex or complexes; (b) contacting mixture from step (a) with a member selected from ammonium polysulfide, sodium polysulfide, and mixtures thereof. The mixture is contacted at a temperature of from 110/sup 0/C. to 180/sup 0/C., in a contacting zone and converting iron cyanide complex or complexes in the mixture and producing a mixture having a substantially reduced iron cyanide complex or complexes content.

Baker, D.C.

1986-11-25

233

Nature and Magnitude of Aromatic Stacking of Nucleic Acid Bases  

Microsoft Academic Search

This review summarises recent advances in quantum chemical calculations of base-stacking forces in nucleic acids. We explain in detail the very complex relationship between the gas-phase basestacking energies, as revealed by quantum chemical (QM) calculations, and the highly variable roles of these interactions in nucleic acids. This issue is rarely discussed in quantum chemical and physical chemistry literature. We further

Jiri Sponer; Kevin E. Riley; Pavel Hobza

2008-01-01

234

SiC particulate reinforced Al–12Si alloy composite coatings produced by the pulsed gas dynamic spray process: Microstructure and properties  

Microsoft Academic Search

The work presented in this paper examine the possibility of using the pulsed gas dynamic spraying (PGDS) process as a new production technique of Al–12Si alloy coatings and (Al–12Si+SiCp) composite coatings using feedstock powder containing 20, 40, and 60 (vol.%) reinforcement particles. In this study the effect of the processing conditions, in particular the gas preheating temperature and pressure and

M. Yandouzi; P. Richer; B. Jodoin

2009-01-01

235

Designing wet duct/stack systems for coal-fired plants  

SciTech Connect

A multitude of variables must be accounted for during the design and development of a wet-stack flue gas desulfurization system. The five-phase process detailed in this article has proven effective on more than 60 wet-stack system design studies. The process is the result of studies by EPRI detailed in two reports entitled: entrainment in wet stacks', and 'wet stacks design guide. A basic understanding of these concepts will help inform early design decisions and produce a system amenable to wet operation. 2 refs., 5 figs.

Anderson, D.K.; Maroti, L.A. [Alden Research Laboratory Inc. (United States)

2006-03-15

236

Determination and Evaluation of Stack Emissions From Municipal Incinerators  

Microsoft Academic Search

A comprehensive incinerator air pollution control testing program was recently completed in New York City, and the results contain valuable particulate and gas sampling data. The information, which was obtained from a large number of test runs, is especially valuable since there is a shortage of reliable, valid test data of this nature. Since the test data now presented involved

Peter Franconeri; Lawrence Kaplan

1976-01-01

237

40 CFR 75.72 - Determination of NOX mass emissions for common stack and multiple stack configurations.  

Code of Federal Regulations, 2013 CFR

...Determination of NOX mass emissions for common stack and multiple stack configurations...Determination of NOX mass emissions for common stack and multiple stack configurations...monitoring systems on the main stack and the emissions measured by the...

2013-07-01

238

40 CFR 75.72 - Determination of NOX mass emissions for common stack and multiple stack configurations.  

Code of Federal Regulations, 2010 CFR

...Determination of NOX mass emissions for common stack and multiple stack configurations...Determination of NOX mass emissions for common stack and multiple stack configurations...monitoring systems on the main stack and the emissions measured by the...

2009-07-01

239

Split stack blowout prevention system  

SciTech Connect

A blowout prevention system for an offshore structure positioned on the underwater bottom in a body of water which contains moving ice masses that could force the structure off location wherein a surface blowout preventer stack for conventional well control is connected to the upper end of a riser with the lower end of the riser being disconnectably connected to a subsurface blowout preventer stack which provides the necessary well control should the structure be forced off location. The subsurface stack is positioned on a wellhead located in a chamber in the subsea bottom and is disconnectably connected to the riser so that the riser may be quickly removed from the subsea bottom should the structure be forced off location.

Crager, B.L.; Ray, D.R.; Steddum, R.E.

1980-03-18

240

Operational problems associated with the use of particulate emission control for MACT compliance applications  

Microsoft Academic Search

Tests of high-efficiency particulate air filters were requested following catastrophic failure of a filter by hydrogen fluoride gas from improper operation in a production line. Operational lives in hydrogen fluoride environments of high-efficiency particulate air filters were determined in statistically designed experiments for three variable. The variables studied were hydrogen fluoride gas concentration, water vapor concentration, and wind speed through

1992-01-01

241

Magnetic and recording characterization of Ba-ferrite particulate rigid disk media  

Microsoft Academic Search

Orinted Ba-ferrite (BF) particulate media exhibit very good high density recording characteristics, as a result of very narrow switching fields and very square remanence loops. Until recently, however, the very smooth BF platelets employed in these coatings had a strong tendency to stack, thus increasing media noise. Some of the latest BF pigments incorporate surface treatments which greatly facilitate their

D. E. Speliotis; J. P. Judge; W. Lynch; J. Burbage; R. Keirsted

1993-01-01

242

An ultraviolet video technique for visualization of stack plumes and for measuring sulfur dioxide concentration and effluent velocity  

Microsoft Academic Search

Absorption spectroscopy utilizing a video sensing technique was investigated as a means of visualizing SO2 in power plant stack plumes and for measuring SO2 concentration and effluent velocity in these plumes. The absorption of SO2 is measured in the ultraviolet region by using the sky as a background source. An additional spectral channel is used to correct for particulate scattering

Exton

1977-01-01

243

ADVANCED HYBRID PARTICULATE COLLECTOR  

SciTech Connect

A new concept in particulate control, called an advanced hybrid particulate collector (AHPC), is being developed under funding from the US Department of Energy. The AHPC combines the best features of electrostatic precipitators (ESPs) and baghouses in a manner that has not been done before. The AHPC concept consists of a combination of fabric filtration and electrostatic precipitation in the same housing, providing major synergism between the two collection methods, both in the particulate collection step and in transfer of the dust to the hopper. The AHPC provides ultrahigh collection efficiency, overcoming the problem of excessive fine-particle emission with conventional ESPs, and it solves the problem of reentrainment and collection of dust in conventional baghouses.

Stanley J. Miller; Grant L. Schelkoph

1998-11-13

244

Void/particulate detector  

DOEpatents

Voids and particulates are detected in a flowing stream of fluid contained in a pipe by a detector which includes three transducers spaced about the pipe. A first transducer at a first location on the pipe transmits an ultrasonic signal into the stream. A second transducer detects the through-transmission of the signal at a second location and a third transducer at a third location upstream from the first location detects the back-scattering of the signal from any voids or particulates. To differentiate between voids and particulates a fourth transducer is positioned at a fourth location which is also upstream from the first location. The back-scattered signals are normalized with the through-transmission signal to minimize temperature fluctuations.

Claytor, Thomas N. (Woodridge, IL); Karplus, Henry B. (Hinsdale, IL)

1985-01-01

245

ADVANCED HYBRID PARTICULATE COLLECTOR  

SciTech Connect

A new concept in particulate control, called an advanced hybrid particulate collector (AHPC), is being developed under funding from the US Department of Energy. The AHPC combines the best features of electrostatic precipitators (ESPs) and baghouses in a manner that has not been done before. The AHPC concept consists of a combination of fabric filtration and electrostatic precipitation in the same housing, providing major synergism between the two collection methods, both in the particulate collection step and in the transfer of dust to the hopper. The AHPC provides ultrahigh collection efficiency, overcoming the problem of excessive fine-particle emission with conventional ESPs, and it solves the problem of reentrainment and collection of dust in conventional baghouses. The AHPC is currently being tested at the 2.7-MW scale at the Big Stone power station.

Stanley Miller; Rich Gebert; William Swanson

1999-11-01

246

Anharmonic stacking in supercoiled DNA  

NASA Astrophysics Data System (ADS)

Multistep denaturation in a short circular DNA molecule is analyzed by a mesoscopic Hamiltonian model which accounts for the helicoidal geometry. Computation of melting profiles by the path integral method suggests that stacking anharmonicity stabilizes the double helix against thermal disruption of the hydrogen bonds. Twisting is essential in the model to capture the importance of nonlinear effects on the thermodynamical properties. In a ladder model with zero twist, anharmonic stacking scarcely affects the thermodynamics. Moderately untwisted helices, with respect to the equilibrium conformation, show an energetic advantage against the overtwisted ones. Accordingly moderately untwisted helices better sustain local fluctuational openings and make more unlikely the thermally driven complete strand separation.

Zoli, Marco

2012-05-01

247

Anharmonic stacking in supercoiled DNA.  

PubMed

Multistep denaturation in a short circular DNA molecule is analyzed by a mesoscopic Hamiltonian model which accounts for the helicoidal geometry. Computation of melting profiles by the path integral method suggests that stacking anharmonicity stabilizes the double helix against thermal disruption of the hydrogen bonds. Twisting is essential in the model to capture the importance of nonlinear effects on the thermodynamical properties. In a ladder model with zero twist, anharmonic stacking scarcely affects the thermodynamics. Moderately untwisted helices, with respect to the equilibrium conformation, show an energetic advantage against the overtwisted ones. Accordingly moderately untwisted helices better sustain local fluctuational openings and make more unlikely the thermally driven complete strand separation. PMID:22495298

Zoli, Marco

2012-04-11

248

Inhalation of phosphine gas following a fire associated with fumigation of processed pistachio nuts.  

PubMed

On December 10, 2009, a fumigation stack containing aluminum phosphide became soaked with rain water and caught fire at a pistachio processing plant in Kern County, California. Untrained plant personnel responding to the fire had exposure to pyrolysis by-products, particulates, and extinguisher ingredients. Ten workers taken for medical evaluation had respiratory and nonspecific systemic symptoms consistent with exposure to phosphine gas. Six of the 10 workers had respiratory distress, indicated by chest pain, shortness of breath, elevated respiratory rate, or decreased oxygen saturation. Recommendations are made for the management of similar illnesses and prevention of similar exposures. PMID:23540306

O'Malley, Michael; Fong, Harvard; Sánchez, Martha E; Roisman, Rachel; Nonato, Yvette; Mehler, Louise

2013-01-01

249

JV Task 95-Particulate Control Consulting for Minnesota Ore Operations  

SciTech Connect

The purpose of the project was to assist U.S. Steel in the evaluation, selection, planning, design, and testing of potential approaches to help meet U.S. Steel's goal for low-particulate matter emissions and regulatory compliance. The energy-intensive process for producing iron pellets includes treating the pellets in high-temperature kilns in which the iron is converted from magnetite to hematite. The kilns can be fired with either natural gas or a combination of gas and coal or biomass fuel and are equipped with wet venturi scrubbers for particulate control. Particulate measurements at the inlet and outlet of the scrubbers and analysis of size-fractionated particulate samples led to an understanding of the effect of process variables on the measured emissions and an approach to meet regulatory compliance.

Stanley Miller

2008-10-31

250

POLYMERIC INTERFACES FOR STACK MONITORING  

EPA Science Inventory

Research has been performed on the use of polymeric interfaces for in situ continuous stack monitoring of gaseous pollutants. Permeabilities of candidate interface materials to SO2 were measured at temperatures from ambient to 200C, and the results were used to design interfaces ...

251

V-Stack piezoelectric actuator  

NASA Astrophysics Data System (ADS)

Aeroelastic control of wings by means of a distributed, trailing-edge control surface is of interest with regards to maneuvers, gust alleviation, and flutter suppression. The use of high energy density, piezoelectric materials as motors provides an appealing solution to this problem. A comparative analysis of the state of the art actuators is currently being conducted. A new piezoelectric actuator design is presented. This actuator meets the requirements for trailing edge flap actuation in both stroke and force. It is compact, simple, sturdy, and leverages stroke geometrically with minimum force penalties while displaying linearity over a wide range of stroke. The V-Stack Piezoelectric Actuator, consists of a base, a lever, two piezoelectric stacks, and a pre-tensioning element. The work is performed alternately by the two stacks, placed on both sides of the lever. Pre-tensioning can be readily applied using a torque wrench, obviating the need for elastic elements and this is for the benefit of the stiffness of the actuator. The characteristics of the actuator are easily modified by changing the base or the stacks. A prototype was constructed and tested experimentally to validate the theoretical model.

Ardelean, Emil V.; Clark, Robert L.

2001-07-01

252

STACK SAMPLING FOR ORGANIC EMISSIONS  

EPA Science Inventory

The paper reviews some of the more important principles involved in stack sampling for organics, briefly describes and discusses recently developed equipment, and points out a few of the more serious pitfalls. Extensive references are provided, many of which are often overlooked ...

253

Singularity: rethinking the software stack  

Microsoft Academic Search

Every operating system embodies a collection of design decisions. Many of the decisions behind today's most popular operating systems have remained unchanged, even as hardware and software have evolved. Operating systems form the foundation of almost every software stack, so inadequacies in present systems have a pervasive impact. This paper describes the efforts of the Singularity project to re-examine these

Galen C. Hunt; James R. Larus

2007-01-01

254

Progress Update: Stack Project Complete  

ScienceCinema

Progress update from the Savannah River Site. The 75 foot 293 F Stack, built for plutonium production, was cut down to size in order to prevent injury or release of toxic material if the structure were to collapse due to harsh weather.

255

Optimisation of a selective method for the determination of organophosphorous triesters in outdoor particulate samples by pressurised liquid extraction and large-volume injection gas chromatography-positive chemical ionisation-tandem mass spectrometry.  

PubMed

A selective analytical method for the determination of nine organophosphate triesters and triphenylphosphine oxide (TPPO) in outdoor particulate matter is presented. It involves a fully automated pressurised liquid extraction (PLE) step, integrating an alumina clean-up process, and subsequent determination by large-volume injection gas chromatography-positive chemical ionisation-tandem mass spectrometry (LVI-GC-PCI-MS/MS). The extraction variables (solvent, amount of adsorbent, temperature, time and number of cycles) were optimised using a multicriteria strategy which implements a desirability function that maximises both extraction and clean-up efficiencies while searching for the best-compromise PLE conditions. The final method affords quantification limits of between 0.01 and 0.3 microg g(-1) and recoveries of >80%, with the exceptions of the most polar analytes, TCEP and TPPO (~65%) for both urban dust and PM10 samples. Moreover, the method permitted the levels of these compounds in dust deposited outdoors (between LOD and 0.5 microg g(-1) for TEHP) and PM10 samples (between LOD and 2.4 microg m(-3) for TiBP) to be measured and reported for the first time. PMID:17534607

Quintana, José Benito; Rodil, Rosario; López-Mahía, Purificación; Muniategui-Lorenzo, Soledad; Prada-Rodríguez, Darío

2007-05-30

256

Analysis of particulate emissions of stoker coal fired boilers  

SciTech Connect

The scope of this paper includes the study of over 100 particulate emission rate compliance test reports collected by the American Boiler Manufacturers Association under a program entitled ''A Testing Program to Update Equipment Specifications and Design Criteria for Stoker-Fired Boilers'', and analysis of the results of selected tests. All of the 98 tests reported in this study were conducted in accordance with EPA Method 5, ''Determination of Particulate Emissions from Stationary Sources'', and were observed by state and/or federal enforcement officials. A total of 45 small institutional and industrial multiple pass boilers in the size range of 10,000 to 77,000 lb/hr maximum steam output are represented in the test data. Stoker types include multiple and single retort underfeed, and traveling grate (chain and bar-key) and vibrating grate overfeed. Coals fired include Pennsylvania anthracite and bituminous, and Indiana bituminous. Sample locations for the particulate emission rate tests include boiler outlet, breeching, short stub stack downstream of mechanical collector, and tall masonry stack. The tests were conducted with boilers operating at normal conditions, and fired with coal from the normal source.

Owens, H.K.; Axtman, W.H.; Davis, J.W.

1983-06-01

257

Theoretical Evidence for the Stronger Ability of Thymine to Disperse SWCNT than Cytosine and Adenine: self-stacking of DNA bases vs their cross-stacking with SWCNT.  

PubMed

Self-stacking of four DNA bases, adenine (A), cytosine (C), guanine (G) and thymine (T), and their cross-stacking with (5,5) as well as (10,0) single walled carbon nanotubes (SWCNTs) were extensively investigated with a novel hybrid DFT method, MPWB1K/cc-pVDZ. The binding energies were further corrected with MP2/6-311++G(d,p) method in both gas phase and aqueous solution, where the solvent effects were included with conductor-like polarized continuum model (CPCM) model and UAHF radii. The strongest self-stacking of G and A takes displaced anti-parallel configuration, but un-displaced or "eclipsed" anti-parallel configuration is the most stable for C and T. In gas phase the self-stacking of nucleobases decreases in the sequence G>A>C>T, while because of quite different solvent effects their self-stacking in aqueous solution exhibits a distinct sequence A>G>T>C. For a given base, cross-stacking is stronger than self-stacking in both gas phase and aqueous solution. Binding energy for cross-stacking in gas phase varies as G>A>T>C for both (10,0) and (5,5) SWCNTs, and the binding of four nucleobases to (10,0) is slightly stronger than to (5,5) SWCNT by a range of 0.1-0.5 kcal/mol. The cross-stacking in aqueous solution varies differently from that gas phase: A>G>T>C for (10,0) SWCNT and G>A>T>C for (5,5) SWCNT. It is suggested that the ability of nucleobases to disperse SWCNT depends on relative strength [Formula: see text] of self-stacking and cross-stacking with SWCNT in aqueous solution. Of the four investigated nucleobases thymine (T) exhibits the highest [Formula: see text] which can well explain the experimental finding that T more efficiently functionalizes SWCNT than C and A. PMID:18946514

Wang, Yixuan

2008-01-01

258

Anomaly Detection Using Call Stack Information  

Microsoft Academic Search

The call stack of a program execution can be a very good information source for intrusion detection. There is no pri or work on dynamically extracting information from call stack and effectively using it to detect exploits. In this paper, w e propose a new method to do anomaly detection using call stack information. The basic idea is to extract

Henry Hanping Feng; Oleg M. Kolesnikov; Prahlad Fogla; Wenke Lee; Weibo Gong

2003-01-01

259

Stacking faults in Si nanocrystals  

SciTech Connect

Si nanocrystals (Si nc) were formed by the implantation of Si{sup +} into a SiO{sub 2} film on (100) Si, followed by high-temperature annealing. High-resolution transmission electron microscopy has been used to examine the microstructure of the Si nc produced by a high-dose (3x10{sup 17} cm{sup -2}) implantation. It is shown that there are only stacking-fault (SF) defects in some nanocrystals; while in others the stacking faults (SFs) coexist with twins. Two kinds of SFs, one being an intrinsic SF, the other being an extrinsic SF, have been observed inside the Si nc. More intrinsic SFs have been found in the Si nc, and the possible reasons are discussed. These microstructural defects are expected to play an important role in the light emission from the Si nc.

Wang, Y.Q.; Smirani, R.; Ross, G.G. [INRS-EMT, 1650, Boulevard Lionel-Boulet, Varennes, Quebec, J3X 1S2 (Canada)

2005-05-30

260

Solvent influence on base stacking.  

PubMed Central

In this paper we present a detailed analysis of the base-stacking phenomenon in different solvents, using nanosecond molecular dynamics simulations. The investigation focuses on deoxyribo- and ribodinucleoside monophosphates in aqueous and organic solutions. Organic solvents with a low dielectric constant, such as chloroform, and solvents with intermediate dielectric constants, such as dimethyl sulfoxide and methanol, were analyzed. This was also done for water, which is highly polar and has a high dielectric constant. Structural parameters such as the sugar puckering and the base-versus-base orientations, as well as the energetics of the solute-solvent interactions, were examined in the different solvents. The obtained data demonstrate that base stacking is favored in the high dielectric aqueous solution, followed by methanol and dimethyl sulfoxide with intermediate dielectric constants, and chloroform, with a low dielectric constant.

Norberg, J; Nilsson, L

1998-01-01

261

Determination of N-nitrosamines and nicotine in air particulate matter samples by pressurised liquid extraction and gas chromatography-ion trap tandem mass spectrometry.  

PubMed

N-nitrosamines are potentially hazardous pollutants, classified as probable carcinogenic and mutagenic by the U.S. Environmental Protection Agency (EPA). In this paper, the presence of these pollutants was studied in air samples taken at different locations of Tarragona (urban and harbour). As a result, a reliable method has been developed for determining N-nitrosamines and nicotine based on pressurised liquid extraction (PLE) and gas chromatography-(chemical ionisation) ion trap tandem mass spectrometry (GC-(CI)MS/MS). The chromatographic analysis enables the determination of these compounds in less than 13min with total separation and good resolution between the compounds. Recovery values were higher than 80% for most of the compounds and the repeatability of the method was under 18% (5ngm(-3), %RSD, n=4). MDLs were between 0.1ngm(-3) (NMor and NPip) and 2ngm(-3) (NMEA). NMor, NPyr, NPip and nicotine were the most frequent compounds in urban and harbour samples at concentration levels between 0.3ngm(-3) (NPyr) and 12.5ngm(-3) (nicotine) and between 0.13ngm(-3) (NPyr) and 3.8ngm(-3) (nicotine), respectively. PMID:24054680

Aragón, M; Marcé, R M; Borrull, F

2013-07-12

262

PRECISION COSMOGRAPHY WITH STACKED VOIDS  

SciTech Connect

We present a purely geometrical method for probing the expansion history of the universe from the observation of the shape of stacked voids in spectroscopic redshift surveys. Our method is an Alcock-Paczynski (AP) test based on the average sphericity of voids posited on the local isotropy of the universe. It works by comparing the temporal extent of cosmic voids along the line of sight with their angular, spatial extent. We describe the algorithm that we use to detect and stack voids in redshift shells on the light cone and test it on mock light cones produced from N-body simulations. We establish a robust statistical model for estimating the average stretching of voids in redshift space and quantify the contamination by peculiar velocities. Finally, assuming that the void statistics that we derive from N-body simulations is preserved when considering galaxy surveys, we assess the capability of this approach to constrain dark energy parameters. We report this assessment in terms of the figure of merit (FoM) of the dark energy task force and in particular of the proposed Euclid mission which is particularly suited for this technique since it is a spectroscopic survey. The FoM due to stacked voids from the Euclid wide survey may double that of all other dark energy probes derived from Euclid data alone (combined with Planck priors). In particular, voids seem to outperform baryon acoustic oscillations by an order of magnitude. This result is consistent with simple estimates based on mode counting. The AP test based on stacked voids may be a significant addition to the portfolio of major dark energy probes and its potentialities must be studied in detail.

Lavaux, Guilhem [Department of Physics, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Wandelt, Benjamin D. [UPMC Univ Paris 06, UMR 7095, Institut d'Astrophysique de Paris, 98 bis, boulevard Arago, 75014 Paris (France)

2012-08-01

263

Feature-Weighted Linear Stacking  

Microsoft Academic Search

Ensemble methods, such as stacking, are designed to boost predictive accuracy\\u000aby blending the predictions of multiple machine learning models. Recent work\\u000ahas shown that the use of meta-features, additional inputs describing each\\u000aexample in a dataset, can boost the performance of ensemble methods, but the\\u000agreatest reported gains have come from nonlinear procedures requiring\\u000asignificant tuning and training time.

Joseph Sill; Gábor Takács; Lester Mackey; David Lin

2009-01-01

264

Void/particulate detector  

DOEpatents

Apparatus for detecting voids and particulates in a flowing stream of fluid contained in a pipe may comprise: (a) a transducer for transmitting an ultrasonic signal into the stream, coupled to the pipe at a first location; (b) a second transducer for detecting the through-transmission of said signal, coupled to the pipe at a second location; (c) a third transducer for detecting the back-scattering of said signal, coupled to the pipe at a third location, said third location being upstream from said first location; (d) circuit means for normalizing the back-scattered signal from said third transducer to the through-transmitted signal from said second transducer; which normalized signal provides a measure of the voids and particulates flowing past said first location.

Claytor, T.N.; Karplus, H.B.

1983-09-26

265

ADVANCED HYBRID PARTICULATE COLLECTOR  

SciTech Connect

A new concept in particulate control, called an advanced hybrid particulate collector (AHPC), is being developed under funding from the US Department of Energy. The AHPC combines the best features of electrostatic precipitators (ESPs) and baghouses in an entirely novel manner. The AHPC concept combines fabric filtration and electrostatic precipitation in the same housing, providing major synergism between the two methods, both in the particulate collection step and in transfer of dust to the hopper. The AHPC provides ultrahigh collection efficiency, overcoming the problem of excessive fine-particle emissions with conventional ESPs, and solves the problem of reentrainment and recollection of dust in conventional baghouses. Phase I of the development effort consisted of design, construction, and testing of a 5.7-m{sup 3}/min (200-acfm) working AHPC model. Results from both 8-hour parametric tests and 100-hour proof-of-concept tests with two different coals demonstrated excellent operability and greater than 99.99% fine-particle collection efficiency.

Stanley J. Miller; Grant L. Schelkoph; Grant E. Dunham

2000-12-01

266

Unabated emission source term estimate for the 340-NX stack  

SciTech Connect

This document contains the sampling procedure, analytical results, and source term estimate from sampling work conducted on the main stack for the 340 Facility`s vault ventilation system. Several air filter and carbon cartridges were collected upstream of the KI off-gas control modules in order to determine the challenge source terms associated with various operating modes (e.g., under routine waste storage, during waste mixing, during waste transfer, etc.)

Stordeur, R.T.; Glissmeyer, J.A., Fluor Daniel Hanford

1997-03-19

267

Nonlinear acoustic impedance of thermoacoustic stack  

NASA Astrophysics Data System (ADS)

In order to optimize the performances of the thermoacoustic refrigerator working with the high sound pressure level, the nonlinear acoustic characteristics of the thermoacoustic stack in the resonant pipe are studied. The acoustic fluid impedance of the stack made of copper mesh and set up in a resonant pipe is measured in the acoustic fields with different intensities. It is found that when the sound pressure level in the pipe increases to a critical value, the resistance of the stack increases nonlinearly with the sound pressure, while the reactance of the stack keeps constant. Based on the experimental results, a theory model is set up to describe the acoustic characteristics of the stack, according to the rigid frame theory and Forchheimmer equation. Furthermore, the influences of the sound pressure level, operating frequency, volume porosity, and length of the stack on the nonlinear impedance of the stack are evaluated.

Ge, Huan; Fan, Li; Xiao, Shu-yu; Tao, Sha; Qiu, Mei-chen; Zhang, Shu-yi; Zhang, Hui

2012-09-01

268

Stacks  

ERIC Educational Resources Information Center

|Linton Waters and Jayne Kranat ran a session on the Nuffield "Applying Mathematical Processes" (AMP) activities at BCME7 in Manchester in April this year. These 1-2 hour activities are revamps of some of the Graded Assessment in Mathematics (GAIM) resources, developed in the 1980s, and are freely available via the Nuffield website and the…

Kimber, Lizzie

2010-01-01

269

Stacks  

ERIC Educational Resources Information Center

Linton Waters and Jayne Kranat ran a session on the Nuffield "Applying Mathematical Processes" (AMP) activities at BCME7 in Manchester in April this year. These 1-2 hour activities are revamps of some of the Graded Assessment in Mathematics (GAIM) resources, developed in the 1980s, and are freely available via the Nuffield website and the original…

Kimber, Lizzie

2010-01-01

270

Contribution of particulate nitrate to airborne measurements of total reactive nitrogen  

Microsoft Academic Search

Simultaneous measurements of speciated, total reactive nitrogen (NOy) and particulate NO3- (particle diameter <1.3 mum) were made on board the NASA P-3B aircraft over the western Pacific in February-April 2001 during the Transport and Chemical Evolution over the Pacific (TRACE-P) experiment. Gas-phase and particulate NOy was measured using a gold tube catalytic converter. For the interpretation of particulate NOy, conversion

Y. Miyazaki; Y. Kondo; N. Takegawa; R. J. Weber; M. Koike; K. Kita; M. Fukuda; Y. Ma; A. D. Clarke; V. N. Kapustin; F. Flocke; A. J. Weinheimer; M. Zondlo; F. L. Eisele; D. R. Blake; B. Liley

2005-01-01

271

Contribution of particulate nitrate to airborne measurements of total reactive nitrogen  

Microsoft Academic Search

Simultaneous measurements of speciated, total reactive nitrogen (NOy) and particulate NO3? (particle diameter <1.3 ?m) were made on board the NASA P-3B aircraft over the western Pacific in February–April 2001 during the Transport and Chemical Evolution over the Pacific (TRACE-P) experiment. Gas-phase and particulate NOy was measured using a gold tube catalytic converter. For the interpretation of particulate NOy, conversion

Y. Miyazaki; Y. Kondo; N. Takegawa; R. J. Weber; M. Koike; K. Kita; M. Fukuda; Y. Ma; A. D. Clarke; V. N. Kapustin; F. Flocke; A. J. Weinheimer; M. Zondlo; F. L. Eisele; D. R. Blake; B. Liley

2005-01-01

272

Particulate Matter: a closer look  

Microsoft Academic Search

The summary in booklet form 'Fijn stof nader bekeken' (Particulate\\u000aMatter: a closer look) , published in Dutch by the Netherlands\\u000aEnvironmental Assessment Agency (MNP) and the Environment and Safety\\u000aDivision of the National Institute for Public Health and the Environment\\u000a(RIVM), has been designed to present the facts on particulate matter in a\\u000acoherent framework. Current knowledge on particulate

Buijsman E; Beck JP; Bree L van; Cassee FR; Koelemeijer RBA; Matthijsen J; Thomas R; Wieringa K

2007-01-01

273

Conversion of SO2 to sulfur particulate in the Los Angeles atmosphere.  

PubMed Central

Gas phase and particular phase sulfur have been measured at various locations in the Los Angeles basin to determine atmospheric conversion rates and mechanisms. A new technique was developed for the measurement of particulate sulfur. From measurements of the particulate to gas phase sulfur ratio near the major stationary sources and far downstream and from estimates of travel time determined by air trajectory analysis, it is possible to estimate gas-to-particle conversion rates for sulfur. Such calculations show that automobiles presently contribute a major part of the total sulfur as measured at a receptor site such as Pasadena, while contributing only a small amount to the particulate sulfur loading. The introduction of oxidation catalyst-equipped vehicles may add significantly to the particulate sulfur at downwind receptor sites; predictions of particulate sulfur concentrations near freeways show substantial increases due to such vehicles.

Roberts, P T; Friedlander, S K

1975-01-01

274

Dust particulate-phonon interaction  

SciTech Connect

Collective behavior of dust particulates placed in a plasma sheath in the presence of ion acoustic wave is studied. The interaction between dust particulates and ion acoustic wave is treated as a scattering process between dust particulates and phonons (quasi-particles of ion acoustic wave). It is shown that when the streaming of ions becomes supersonic, the system is stable and the ordered structure of plasma crystal is expected to form in the potential of shock-like wake. When the streaming velocity becomes subsonic, the system becomes unstable and the dust particulates are expected to experience phase transition and to show disordered structure.

Ishihara, Osamu [Department of Electrical Engineering and Department of Physics, Texas Tech University, Lubbock, Texas 79409-3102 (United States)

1998-10-21

275

MERCURY CONTROL WITH ADVANCED HYBRID PARTICULATE COLLECTOR  

SciTech Connect

This project was awarded under U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL) Program Solicitation DE-PS26-00NT40769 and specifically addressed Technical Topical Area 4-Testing Novel and Less Mature Control Technologies on Actual Flue Gas at the Pilot Scale. The project team included the Energy & Environmental Research Center (EERC) as the main contractor; W.L. Gore & Associates, Inc., as a technical and financial partner; and the Big Stone Power Plant operated by Otter Tail Power Company, host for the field-testing portion of the research. Since 1995, DOE has supported development of a new concept in particulate control called the advanced hybrid particulate collector (AHPC). The AHPC has been licensed to W.L. Gore & Associates, Inc., and has been marketed as the Advanced Hybrid{trademark} filter by Gore. The Advanced Hybrid{trademark} filter combines the best features of electrostatic precipitators (ESPs) and baghouses in a unique configuration, providing major synergism between the two collection methods, both in the particulate collection step and in the transfer of dust to the hopper. The Advanced Hybrid{trademark} filter provides ultrahigh collection efficiency, overcoming the problem of excessive fine-particle emissions with conventional ESPs, and it solves the problem of reentrainment and re-collection of dust in conventional baghouses. The Advanced Hybrid{trademark} filter also appears to have unique advantages for mercury control over baghouses or ESPs as an excellent gas--solid contactor. The objective of the project was to demonstrate 90% total mercury control in the Advanced Hybrid{trademark} filter at a lower cost than current mercury control estimates. The approach included bench-scale batch tests, larger-scale pilot testing with real flue gas on a coal-fired combustion system, and field demonstration at the 2.5-MW (9000-acfm) scale at a utility power plant to prove scale-up and demonstrate longer-term mercury control. An additional task was included in this project to evaluate mercury oxidation upstream of a dry scrubber by using mercury oxidants. This project demonstrated at the pilot-scale level a technology that provides a cost-effective technique to control mercury and, at the same time, greatly enhances fine particulate collection efficiency. The technology can be used to retrofit systems currently employing inefficient ESP technology as well as for new construction, thereby providing a solution for improved fine particulate control combined with effective mercury control for a large segment of the U.S. utility industry as well as other industries.

Ye Zhuang; Stanley J. Miller

2005-05-01

276

Seeing Galaxies Through the Forest: Spectral Stacking of Damped Lyman Alpha Systems  

NASA Astrophysics Data System (ADS)

Damped Lyman alpha Systems (DLAs) are the highest column density (N(HI) >= 2x10^20 cm^-2) neutral gas absorbers detected in the sightlines to distant quasars. DLAs dominate the neutral gas mass content of the Universe from z=[0,5], suggesting that they are the reservoirs of neutral gas for star formation across cosmic time. However, the nature of DLAs is not fully understood because they are detected in absorption against the light of background quasars. The resulting spectra contain absorption from the Lyman alpha forest, a series of smaller neutral hydrogen lines, essentially filaments of neutral gas in the IGM. At high redshifts (z >= 2), the forest becomes quite thick, making it difficult to distinguish intervening forest lines from metal lines of the DLA. By employing the technique of spectral stacking, we essentially subtract the incoherent Lyman alpha forest lines, enabling us to measure metal lines that typically fall in the forest region, such as O VI, N V, and molecular hydrogen. In addition, the increased signal-to-noise ratio in the DLA stack allows us to search for the presence of weak metal lines and/or Lyman alpha emission not typically seen in a single DLA spectrum. We will present the results obtained from our stack of 97 high-resolution (FWHM ~ 8 km/s) VLT/UVES spectra. Initial analysis of the stack shows a possible detection of Lyman alpha emission in the DLA trough. We will combine this VLT/UVES stack with a previously created stack of ~110 Keck/HIRES spectra to create the highest signal-to-noise ratio, high-resolution DLA spectral stack. Analysis of this final stack will shed new light on our understanding of the role of DLAs in galaxy formation and evolution. This work was conducted by a Research Experience for Undergraduates (REU) position at the University of Hawai'i's Institute for Astronomy and funded by the NSF.

Yen, Steffi; Jorgenson, R.; Murphy, M.

2013-01-01

277

Diesel particulate composition changes along an air cooled exhaust pipe and dilution tunnel  

Microsoft Academic Search

Exhaust particulate and gas composition samples were obtained at various distances along an externally air cooled exhaust from a Perkins 4-236 single cylinder engine. The change in the particulate composition was determined as a function of the exhaust distance and local temperature. Exhaust temperatures were in the range 200 - 260C at entry to the tunnel at all engine conditions.

M. K. Abbass; G. E. Andrews; P. T. Williams; K. D. Bartle

1989-01-01

278

Analysis of reformed EGR on the performance of a diesel particulate filter  

Microsoft Academic Search

The use of a diesel particulate filter (DPF) in combination with an upstream diesel oxidation catalyst (DOC) has been successfully implemented and shown to reduce carbon monoxide (CO), hydrocarbon (HC) and Particulate Matter (PM) diesel exhaust gas emissions. However issues including cost, size and uncontrolled active regeneration under a low temperature window still require attention. This study therefore primarily focuses

S. S. Gill; G. S. Chatha; A. Tsolakis

2011-01-01

279

CAPSULE REPORT: PARTICULATE CONTROL BY FABRIC FILTRATION ON COAL-FIRED INDUSTRIAL BOILERS  

EPA Science Inventory

Interest in fabric filtration for boiler particulate control has increased due to the conversion of oil- and gas- to coal-fired boilers and the promulgation of more stringent particulate emission regulations. his report describes the theory, applications, performance, and economi...

280

Development of internal manifold heat exchanger (IMHEX reg sign ) molten carbonate fuel cell stacks  

Microsoft Academic Search

The Institute of Gas Technology (IGT) has been in the forefront of molten carbonate fuel cell (MCFC) development for over 25 years. Numerous cell designs have been tested and extensive tests have been performed on a variety of gas manifolding alternatives for cells and stacks. Based upon the results of these performance tests, IGT's development efforts started focusing on an

L. G. Marianowski; E. T. Ong; R. J. Petri; R. J. Remick

1991-01-01

281

Flame Temperature in Oil-Fired Fuel-Burning Equipment and its Relationship to Carbonaceous Particulate Emissions  

Microsoft Academic Search

Field tests were conducted on 82 fuel-burning installations ranging from 50 to 500 hp, fired with residual fuel oils. A flame pyrometer was used to measure peak flame temperatures. Coarse particulates were measured by impingement on adhesive paper strips inserted at right angles to the gas flow and fine particulates by filtration of the gas sample through filter paper. Both

H. A Belyea; W. J Holland

1967-01-01

282

Stacking Fault Energies of Tetrahedrally Coordinated Crystals  

Microsoft Academic Search

The energies of the intrinsic stacking fault in 20 tetrahedrally coordinated crystals, determined by electron microscopy from the widths of extended dislocations, range from a few mJ\\/m2 to 300 mJ\\/m2. The reduced stacking fault energy (RSFE: stacking fault energy per bond perpendicular to the fault plane) has been found to have correlations with the effective charge, the charge redistribution index

S. Takeuchi; K. Suzuki

1999-01-01

283

Improvement of phosphoric acid fuel cell stacks  

Microsoft Academic Search

Phosphoric acid fuel cell components and stack assembly methods were evaluated. Electrodes with Pt loading between 0.3 and 0.9 g\\/sq. ft. were employed. Matrix materials were phenolic (Kynol) fibers and SiC. Graphite bipolar plates with 33% phenolic resin binder were used. Stacks were tested on hydrogen and simulated reformed methanol for up to 6,800 hours. An 80-cell (2.1 kW) stack

S. G. Abens; F. J. Ascenzo; B. S. Baker; G. Garretson; M. Lambrech

1979-01-01

284

High Performance ‘‘V-stack’’ Piezoelectric Actuator  

Microsoft Academic Search

A comparative analysis of the state-of-the-art actuators is conducted. A new piezoelectric actuator design is presented. It is compact, simple, sturdy, and leverages stroke geometrically with minimum force penalties. The ‘‘V-stack Piezoelectric Actuator’’ consists of a base, a lever, two piezoelectric stacks, and a pretensioning element. Work is performed alternately by the two stacks placed on each side of the

Emil V. Ardelean; Daniel G. Cole; Robert L. Clark

2004-01-01

285

Toxicity of Brass Particulate to Daphnia magna.  

National Technical Information Service (NTIS)

The aquatic toxicity of a brass particulate was examined. Acute, 48-hour bioassays were performed using the water flea, Daphnia magna. Tests were conducted with uniform suspensions of uncoated brass particulate, brass particulate coated with a Teflon solu...

D. W. Johnson M. V. Haley G. S. Hart W. T. Muse W. G. Landis

1985-01-01

286

Electrical coupling in proton exchange membrane fuel cell stacks  

NASA Astrophysics Data System (ADS)

A mathematical model describing the effects of electrical coupling of proton exchange membrane unit fuel cells through shared bipolar plates is developed. Here, the unit cells are described by simple, steady-state, 1D models appropriate for straight reactant gas channel designs. A linear asymptotic version of the model is used to give analytic insight into the effect of the coupling, including estimates of the extent of the coupling in terms of the number of adjacent cells affected. An efficient numerical method is developed to solve the non-linear coupled system. Numerical results showing the effects on stack voltage due to a single cell with anomalous oxidant flow rate are given. The effects on stack performance due to end plate effects are also given. It is shown that electrical coupling has a significant effect on fuel cell performance.

Berg, Peter; Caglar, Atife; Promislow, Keith; St-Pierre, Jean; Wetton, Brian

2006-04-01

287

Regeneration process of ceramic foam diesel-particulate traps  

Microsoft Academic Search

Periodic regeneration of the diesel particulate trap is essential to maintain the collection efficiency and exhaust gas back pressure at acceptable levels. The objectives of this study are to describe the phenomenology of ceramic foam filter regeneration process and to present its mathematical model. Further simulation study is carried out to estimate the effects of various factors including fuel additive

K. Takama; T. Inove; K. Kobashi; T. Kogiso; K. Oishi

1984-01-01

288

High efficiency particulate removal with sintered metal filters  

Microsoft Academic Search

Because of their particle removal efficiencies and durability, sintered metal filters have been chosen for high efficiency particulate air (HEPA) filter protection in the off gas treatment system for a proposed transuranic waste treatment facility. Process evaluation of sintered metal filters indicated a lack of sufficient process design data to ensure trouble free operation. Subsequence pilot scale testing was performed

B. E. Kirstein; W. J. Paplawsky; D. T. Pence; T. G. Hedahl

1981-01-01

289

Scaled Tests and Modeling of Effluent Stack Sampling Location Mixing  

SciTech Connect

The Pacific Northwest National Laboratory researchers used a computational fluid dynamics (CFD) computer code to evaluate the mixing at a sampling system location of a research and development facility. The facility requires continuous sampling for radioactive air emissions. Researchers sought to determine whether the location would meet the criteria for uniform air velocity and contaminant concentration as prescribed in the American National Standard Institute (ANSI) standard, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stacks and Ducts of Nuclear Facilities. Standard ANSI/HPS N13.1-1999 requires that the sampling location be well-mixed and stipulates specific tests (e.g., velocity, gas, and aerosol uniformity and cyclonic flow angle) to verify the extent of mixing.. The exhaust system for the Radiochemical Processing Laboratory was modeled with a CFD code to better understand the flow and contaminant mixing and to predict mixing test results. The CFD results were compared to actual measurements made at a scale-model stack and to the limited data set for the full-scale facility stack. Results indicated that the CFD code provides reasonably conservative predictions for velocity, gas, and aerosol uniformity. Cyclonic flow predicted by the code is less than that measured by the required methods. In expanding from small to full scale, the CFD predictions for full-scale measurements show similar trends as in the scale model and no unusual effects. This work indicates that a CFD code can be a cost-effective aid in design or retrofit of a facility’s stack sampling location that will be required to meet Standard ANSI/HPS N13.1-1999.

Recknagle, Kurtis P.; Yokuda, Satoru T.; Ballinger, Marcel Y.; Barnett, J. M.

2009-02-01

290

Operational problems associated with the use of particulate emission control for MACT compliance applications.  

National Technical Information Service (NTIS)

Tests of high-efficiency particulate air filters were requested following catastrophic failure of a filter by hydrogen fluoride gas from improper operation in a production line. Operational lives in hydrogen fluoride environments of high-efficiency partic...

J. A. Compton

1992-01-01

291

40 CFR 49.128 - Rule for limiting particulate matter emissions from wood products industry sources.  

Code of Federal Regulations, 2013 CFR

...following wood products industry sources: (1... (c) What are the PM10 emission limits for wood products industry sources? These...not in lieu of, the particulate matter...emissions from direct natural gas fired or...

2013-07-01

292

Demagnetizing effects in stacked rectangular prisms  

NASA Astrophysics Data System (ADS)

A numerical, magnetostatic model of the internal magnetic field of a rectangular prism is extended to the case of a stack of rectangular prisms. The model enables the calculation of the spatially resolved, three-dimensional internal field in such a stack given any magnetic state function, stack configuration, temperature distribution and applied magnetic field. In this paper the model is applied to the case of a stack of parallel, ferromagnetic rectangular prisms and the resulting internal field is found as a function of the orientation of the applied field, the number of prisms in the stack, the spacing between the prisms and the packing density of the stack. The results show that the resulting internal field is far from being equal to the applied field and that the various stack configurations investigated affect the resulting internal field significantly and non-linearly. The results have a direct impact on the design of, e.g., active magnetic regenerators made of stacked rectangular prisms in terms of optimizing the internal field.

Christensen, D. V.; Nielsen, K. K.; Bahl, C. R. H.; Smith, A.

2011-06-01

293

Project W-420 stack monitoring system upgrades  

SciTech Connect

This project will execute the design, procurement, construction, startup, and turnover activities for upgrades to the stack monitoring system on selected Tank Waste Remediation System (TWRS) ventilation systems. In this plan, the technical, schedule, and cost baselines are identified, and the roles and responsibilities of project participants are defined for managing the Stack Monitoring System Upgrades, Project W-420.

CARPENTER, K.E.

1999-02-25

294

Sorting Using Networks of Queues and Stacks  

Microsoft Academic Search

AI~STRAC'r. The problem of sorting a sequence of numbers using a network of queues and stacks is presented. A characterization of sequences sortable using parallel queues is given, and partial characterizations of sequences sortable using parallel stacks and networks of queues are given.

Robert Endre Tarjan

1972-01-01

295

Effective Stack Design in Air Pollution Control.  

ERIC Educational Resources Information Center

|Stack design problems fall into two general caterories--(1) those of building re-entry, and (2) those of general area pollution. Extensive research has developed adequate information, available in the literature, to permit effective stack design. A major roadblock to effective design has been the strong belief by architects and engineers that…

Clarke, John H.

1968-01-01

296

Development of internal manifold heat exchanger (IMHEX reg sign ) molten carbonate fuel cell stacks  

SciTech Connect

The Institute of Gas Technology (IGT) has been in the forefront of molten carbonate fuel cell (MCFC) development for over 25 years. Numerous cell designs have been tested and extensive tests have been performed on a variety of gas manifolding alternatives for cells and stacks. Based upon the results of these performance tests, IGT's development efforts started focusing on an internal gas manifolding concept. This work, initiated in 1988, is known today as the IMHEX{reg sign} concept. MCP has developed a comprehensive commercialization program loading to the sale of commercial units in 1996. MCP's role is in the manufacture of stack components, stack assembly, MCFC subsystem testing, and the design, marketing and construction of MCFC power plants. Numerous subscale (1 ft{sup 2}) stacks have been operated containing between 3 and 70 cells. These tests verified and demonstrated the viability of internal manifolding from technical (no carbonate pumping), engineering (relaxed part dimensional tolerance requirements), and operational (good gas sealing) aspects. Simplified fabrication, ease of assembly, the elimination of external manifolds and all associated clamping requirements has significantly lowered anticipated stack costs. Ongoing 1 ft{sup 2} stack testing is generating performance and endurance characteristics as a function of system specified operating conditions. Commercial-sized, full-area stacks (10 ft{sup 2}) are in the process of being assembled and will be tested in November. This paper will review the recent developments the MCFC scale-up and manufacture work of MCP, and the research and development efforts of IGT which support those efforts. 17 figs.

Marianowski, L.G.; Ong, E.T.; Petri, R.J.; Remick, R.J.

1991-01-01

297

Toward the Complete Characterization of Atmospheric Organic Particulate Matter: Derivatization and Two-Dimensional Comprehensive Gas Chromatography/Time of Flight Mass Spectrometry as a Method for the Determination of Carboxylic Acids  

NASA Astrophysics Data System (ADS)

Understanding the composition of atmospheric organic particulate matter (OPM) is essential for predicting its effects on climate, air quality, and health. However, the polar oxygenated fraction (PO-OPM), which includes a significant mass contribution from carboxylic acids, is difficult to speciate and quantitatively determine by current analytical methods such as gas chromatography-mass spectrometry (GC-MS). The method of chemical derivatization and two-dimensional GC with time of flight MS (GCxGC/TOF-MS) was examined in this study for its efficacy in: 1) quantifying a high percentage of the total organic carbon (TOC) mass of a sample containing PO-OPM; 2) quantitatively determining PO-OPM components including carboxylic acids at atmospherically relevant concentrations; and 3) tentatively identifying PO-OPM components. Two derivatization reagent systems were used in this study: BF3/butanol for the butylation of carboxylic acids, aldehydes, and acidic ketones, and BSTFA for the trimethylsilylation (TMS) of carboxylic acids and alcohols. Three alpha-pinene ozonolysis OPM filter samples and a set of background filter samples were collected by collaborators in a University of California, Riverside environmental chamber. Derivatization/GCxGC TOF-MS was used to tentatively identify some previously unidentified ?-pinene ozonolysis products, and also to show the characteristics of all oxidation products determined. Derivatization efficiencies as measured were 40-70% for most butyl derivatives, and 50-58% for most trimethylsilyl derivatives. A thermal optical method was used to measure the TOC on each filter, and a value of the quantifiable TOC mass using a gas chromatograph was calculated for each sample using GCxGC separation and the mass-sensitive response of a flame ionization detector (FID). The TOC quantified using TMS and GCxGC-FID (TMS/TOCGCxGC FID) accounted for 15-23% of the TOC measured by the thermal-optical method. Using TMS and GCxGC/TOF-MS, 8.85% of the thermal optical TOC was measured and 48.2% of the TMS/TOCGCxGC-FID was semi-quantified using a surrogate standard. The carboxylic acids tentatively identified using TMS and GCxGC/TOF-MS accounted for 8.28% of the TOC measured by thermal optical means. GCxGC TOF-MS chromatograms of derivatized analytes showed reduced peak tailing due in part to the lesser interactions of the derivatized analytes with the stationary phase of the chromatography column as compared to the chromatograms of underivatized samples. The improved peak shape made possible the greater separation, quantification, and identification of high polarity analytes. Limits of detection using derivatization and GCxGC/TOF-MS were <1 ng per ?L injected for a series of C2-C6 di-acids, cis-pinonic acid, and dodecanoic acid using both butylation and TMS. Derivatization with GCxGC/TOF-MS was therefore effective for determining polar oxygenated compounds at low concentrations, for determining specific oxidation products not previously identified in OPM, and also for characterizing the probable functional groups and structures of ?-pinene ozonolysis products.

Boris, Alexandra Jeanne

298

CHEMICAL COMPOSITIONS OF FINE PARTICULATES EMITTED FROM OIL-FIRED BOILERS  

Microsoft Academic Search

The purpose of this study was to establish the source profiles of fine particulates (PM2.5) emitted from oil-fired boilers (OFBs) in central Taiwan. All the PM2.5 samples emitted from five eligible OFBs were sampled isokinetically using an in-stack sizing device. Subsequently, the samples were analyzed for water-soluble ionic species, carbon contents and trace metal elements. Results indicated that sulfate, elemental

Man-Ting Cheng; Chia-Pin Chio; Chun-Yen Huang; Jau-Min Chen; Chu-Fang Wang; Chung-Yih Kuo

2008-01-01

299

Magnetic characterization of airborne particulates  

NASA Astrophysics Data System (ADS)

Burning fossil fuels from vehicles, domestics, industries and power plants in the large urban or industrial areas emit significant quantity of anthropogenic particulates which become a potential threat to human health. Here, we present temporal variability of particulate pollution associated with compositional differences, using magnetic measurements and electron microscopic observations. Six different grain-sizes of airborne particulates have been collected by filtering from 10 precipitation events in Seoul, Korea from February 2009 to June 2009. Magnetic concentration proxies show relatively better (R2 >0.6) and poorer correlations (R2 <0.3) with the masses of samples filtered by >0.45 ?m and <0.45 ?m sizes, respectively, suggesting the usefulness of magnetic characterization for the >0.45 ?m particulates. Temporally, magnetic concentrations are higher in the cold season than the warm season. In particular, a significant increase of magnetic concentration is observed in 3 ?m and 1 ?m filters after the Chinese wind-blown dust events, indicating additional influx of fine-grained anthropogenic particulates into Seoul. Microscopic observations identify that increase of magnetic concentration is highly linked with the frequent occurrence of combustion derived particulates (i.e., carbon and/or sulfur mixed particles) than natural alumino-silicates. Overall, the present study demonstrates that magnetic measurements efficiently reflect the concentration of particulates produced from fossil-fuel combustion among the airborne particles from various sources.

Kim, W.; Doh, S.; Yu, Y.

2010-12-01

300

Stacking faults in fatigued titanium single crystals  

SciTech Connect

It is generally accepted that the mechanical behavior and interior dislocation substructure of metals and alloys are functions of the stacking fault energies (SFEs). The higher the SFE, the more difficult it is to split a dislocation into two partial dislocations separated by a stacking fault. Whereas materials with high SFE allow easy cross-slip of screw dislocations. Titanium is known to have a high SFE. Even though stacking faults in titanium have been observed experimentally, there is still doubt on them due to the high values of SFE. The purpose of the present study is to obtain further information on stacking faults in fatigued titanium single crystals and to discuss the relation between stacking fault and twinning.

Tan Xiaoli; Gu Haicheng [Xi`an Jiaotong Univ. (China). Research Inst. for Strength of Metals

1995-12-15

301

Fire extinguishing attachment for chimney stacks  

SciTech Connect

A fire extinguishing attachment including a bracket for mounting on a stove stack and having a tubular guide therethrough. The tubular guide is an elbow tube having an inner end within the stack directed towards the chimney flue and an outer end outside the stack adapted to receive the nozzle of a powder type fire extinguisher. When a chimney fire occurs, the extinguisher is placed over the outer end of the guide end and activated. The powdered material is directed, by the guide, into the stack and up the chimney to the location of the fire thereby extinguishing the fire. The guide and bracket is preferably downstream of the damper in the same section of stack to be close to the chimney, and for unobstructed flow.

Sawtelle, K.

1984-11-13

302

Particulate distribution function evolution for ejecta transport  

SciTech Connect

The time evolution of the ejecta distribution function in a gas is discussed in the context of the recent experiments of W. Buttler and M. Zellner for well characterized Sn surfaces. Evolution equations are derived for the particulate distribution function when the dominant gas-particle interaction in is particulate drag. In the approximation of separability of the distribution function in velocity and size, the solution for the time dependent distribution function is a Fredholm integral equation of the first kind whose kernel is expressible in terms of the vacuum time dependent velocity distribution function measured with piezo probes or Asay foils. The solution of this equation in principle gives the size distribution function. We discuss the solution of this equation and the results of the Buttler - Zellner experiments. These suggest that correlations in velocity and size are necessary for a complete description of the transport dala. The solutions presented also represent an analytic test problem for the calculated distribution function in ejecta transport implementations.

Hammerberg, James Edward [Los Alamos National Laboratory; Plohr, Bradley J [Los Alamos National Laboratory

2010-01-01

303

ADVANCED HYBRID PARTICULATE COLLECTOR  

SciTech Connect

A new concept in particulate control, called an advanced hybrid particulate collector (AHPC), is being developed under funding from the U.S. Department of Energy. The AHPC combines the best features of electrostatic precipitators (ESPs) and baghouses in an entirely novel manner. The AHPC concept combines fabric filtration and electrostatic precipitation in the same housing, providing major synergism between the two methods, both in the particulate collection step and in transfer of dust to the hopper. The AHPC provides ultrahigh collection efficiency, overcoming the problem of excessive fine-particle emissions with conventional ESPs, and solves the problem of reentrainment and re-collection of dust in conventional baghouses. Phase I of the development effort consisted of design, construction, and testing of a 5.7-m{sup 3}/min (200-acfm) working AHPC model. Results from both 8-hr parametric tests and 100-hr proof-of-concept tests with two different coals demonstrated excellent operability and greater than 99.99% fine-particle collection efficiency. Since all of the developmental goals of Phase I were met, the approach was scaled up in Phase II to a size of 255 m{sup 3}/min (9000 acfm) (equivalent in size to 2.5 MW) and was installed on a slipstream at the Big Stone Power Plant. For Phase II, the AHPC at Big Stone Power Plant was operated continuously from late July 1999 until mid-December 1999. The Phase II results were highly successful in that ultrahigh particle collection efficiency was achieved, pressure drop was well controlled, and system operability was excellent. For Phase III, the AHPC was modified into a more compact configuration, and components were installed that were closer to what would be used in a full-scale commercial design. The modified AHPC was operated from April to July 2000. While operational results were acceptable during this time, inspection of bags in the summer of 2000 revealed some membrane damage to the fabric that appeared to be caused by electrical effects. Subsequently, extensive theoretical, bench-scale, and pilot-scale investigations were completed to find an approach to prevent bag damage without compromising AHPC performance. Results showed that the best bag protection and AHPC performance were achieved by using a perforated plate installed between the discharge electrodes and bags. This perforated-plate design was then installed in the 2.5-MW AHPC at Big Stone Power Plant in Big Stone City, South Dakota, and the AHPC was operated from March to June 2001. Results showed that the perforated-plate design solved the bag damage problem and offered even better AHPC performance than the previous design. All of the AHPC performance goals were met, including ultrahigh collection efficiency, high air-to-cloth ratio, reasonable pressure drop, and long bag-cleaning interval.

Ye Zhuang; Stanley J. Miller; Michelle R. Olderbak; Rich Gebert

2001-12-01

304

INTERIOR VIEW LOOKING EAST THROUGH BASE OF STACK NO. 2, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

INTERIOR VIEW LOOKING EAST THROUGH BASE OF STACK NO. 2, STACK NO. 1 VISIBLE THROUGH EAST PORTAL - Greenwood Furnace, Stack No. 2, East of McAlevy's Fort on State Route 305, McAlevys Fort, Huntingdon County, PA

305

Measurement of vehicle particulate emissions.  

PubMed Central

A constant volume sampler (CVS) compatible auto exhaust particulate sampling system has been built which samples exhaust isokinetically at constant temperature. This system yields internally consistent results and is capable of frequent and convenient operation.

Beltzer, M

1975-01-01

306

Experimental study of stack plume rise and dispersion at the power station  

SciTech Connect

This paper describes the primary results of stack plume rise and dispersion experiment at Xu Zhou power station during November-December, 1978. (1) Under neutral and near-neutral stratification conditions, the 2/3 power law is the optimizing formula up to date, because of its calculated values in coincidence with observed. (2) Vertical of the buoyant plume from the tall stack is obviously stronger than that of non buoyant plume from the low stack. It is shown that the concept sof Pasquill(1976) model are acceptable, but formula should be modified. (3) From reliable monitoring data of SO/sub 2/ ground concentration, it is found that the effects of topography and stack height should be comprehensively taken into account in estimating dispersion by gaussian model. (4) It is suggested that in analyzing the stereophoto grammetric data of fluctuating plume, the square deviation of plume distribution should be considered as the sum of two parts--the distribution square deviation of the plume particulates relative to the instantaneous center line of the plume, and the distriubtion square deviaton of the instantaneous center line relative to the average center line of the plume. (5) Lidar is shown to be as effective as steroegraphic method in studying behavior of chimney plumes.

Not Available

1986-10-10

307

Preliminary evaluation of the gaseous effluent sampling and monitoring systems at the 291-Z-1 and 296-Z-3 stacks  

SciTech Connect

The 291-Z-1 and 296-Z-3 stack effluent particulate sampling and monitoring systems are being evaluated for compliance with Atlantic Richfield Hanford Company's Interim Criteria for such systems. This evaluation is part of a study by Battelle-Northwest of gaseous effluent sampling systems in ARHCO facilities. This letter report presents a preliminary evaluation of the mentioned facilities and the indicated improvements needed to meet the Interim Criteria so that conceptual design work for improved systems can be initiated. There is currently underway a detailed study at the two stacks including a series of sampling experiments, the findings of which will not be included in this report. The gaseous effluent sampling system at the 291-Z-1 and 296-Z-3 stacks are very dissimilar and will be treated in separate sections of this report. The discussions for each sampling system will include a brief description and a preliminary evaluation of the systems.

Schwendiman, L.C.; Glissmeyer, J.A.

1992-04-01

308

Barrier RF stacking at Fermilab  

SciTech Connect

A key issue to upgrade the luminosity of the Tevatron Run2 program and to meet the neutrino requirement of the NuMI experiment at Fermilab is to increase the proton intensity on the target. This paper introduces a new scheme to double the number of protons from the Main Injector (MI) to the pbar production target (Run2) and to the pion production target (NuMI). It is based on the fact that the MI momentum acceptance is about a factor of four larger than the momentum spread of the Booster beam. Two RF barriers--one fixed, another moving--are employed to confine the proton beam. The Booster beams are injected off-momentum into the MI and are continuously reflected and compressed by the two barriers. Calculations and simulations show that this scheme could work provided that the Booster beam momentum spread can be kept under control. Compared with slip stacking, a main advantage of this new method is small beam loading effect thanks to the low peak beam current. The RF barriers can be generated by an inductive device, which uses nanocrystal magnet alloy (Finemet) cores and fast high voltage MOSFET switches. This device has been designed and fabricated by a Fermilab-KEK-Caltech team. The first bench test was successful. Beam experiments are being planned.

Weiren Chou et al.

2003-06-04

309

Particulates in aluminum sputtering discharges  

Microsoft Academic Search

Plasma-generated particulates are receiving increasing attention as a possible source of device yield reduction in plasma-assisted etching and deposition processes. We have investigated aluminum sputtering in argon discharges between parallel-plate aluminum electrodes under both direct current and radio frequency excitation. Pulsed laser-induced fluorescence experiments indicate that particulates containing aluminum form in these discharges under conditions in which aluminum sputtering takes

G. M. Jellum; D. B. Graves

1990-01-01

310

Turkish Pupils' Conceptions of the Particulate Nature of Matter  

NASA Astrophysics Data System (ADS)

The purpose of this research study is to explore year 6, 8 & 11 (13, 15 and 17 years old respectively) Turkish pupils' views about the particulate nature of matter within the context of phase changes. About 300 pupils participated in the study. Questionnaires distributed to year 6, 8 and 11 pupils included 6-item open-ended questions about (a) arrangement and movement of particles in a solid, liquid and gas and (b) application of particulate ideas to explain phase changes. In addition to questionnaires, semi-structured interviews were carried out with pupils. Results indicated that many pupils, even older ones, had difficulties in applying the particulate theory to explain phase changes despite science teaching. The study has several implications for both teachers and curriculum designers.

Boz, Yezdan

2006-04-01

311

Slip stacking experiments at Fermilab main injector  

SciTech Connect

In order to achieve an increase in proton intensity, Fermilab Main Injector will use a stacking process called ''slip stacking''. The intensity will be doubled by injecting one train of bunches at a slightly lower energy, another at a slightly higher energy, then bringing them together for the final capture. Beam studies have started for this process and we have already verified that, at least for a low beam intensity, the stacking procedure works as expected. For high intensity operation, development work of the feedback and feedforward systems is under way.

Kiyomi Koba et al.

2003-06-02

312

Dynamic stability of stacked disk type flywheels  

SciTech Connect

A dynamic analysis of a flywheel assembly formed from adhesively bonded stacked fiber-composite disks was performed to determine the stiffness and rigidity of the assembly required to prevent uncontrolled growth in the deformations due to centrifugal force. The analysis shows that stacked disk type flywheels will become unstable when the speed exceeds a critical value. This critical value of speed depends upon the stiffness of the bonded attachments between the disks. Elastomeric bonds do not appear to provide adequate stiffness to insure dynamic stability for high speed stacked disk type flywheels. (LCL)

Younger, F.C.

1981-04-01

313

Improvement of phosphoric acid fuel cell stacks  

NASA Astrophysics Data System (ADS)

Phosphoric acid fuel cell components and stack assembly methods were evaluated. Electrodes with Pt loading between 0.3 and 0.9 g/sq. ft were employed. Matrix materials were phenolic (Kynol) fibers and SiC. A new ERC proprietary matrix was used also. Graphite bipolar plates with 33% phenolic resin binder were used. Stacks were tested on hydrogen and simulated reformed methanol for up to 18,000 hours. Two 80 cell (2.1 kW) stacks and a methanol reformer were built and delivered to MERADCOM.

Abens, S. G.; Ascenzo, F. J.; Baker, B. S.; Garretson, G.; Lambrech, M.

1980-07-01

314

Systolic architecture for fast stack sequential decoders  

NASA Astrophysics Data System (ADS)

The troublesome operation of reordering the stack in stack sequential decoders is alleviated by storing the nodes in a systolic priority queue that delivers the true top node in a short and constant amount of time. A new systolic priority queue is described that allows each decoding step, including retrieval, reordering and storage of the nodes, to take place in a single clock period. A complete decoder architecture designed around this queue is compared to a conventional stack-bucket architecture from both speed and cost points of view. The proposed decoder architecture appears to be faster, affordable, and compatible with convolutional codes having long memory and high coding rate.

Lavoie, Pierre; Haccoun, David; Savaria, Yvon

1994-02-01

315

Stacked vapor fed amtec modules  

DOEpatents

The present invention pertains to a stacked AMTEC module. The invention includes a tubular member which has an interior. The member is comprised of a ion conductor that substantially conducts ions relative to electrons, preferably a beta"-alumina solid electrolyte, positioned about the interior. A porous electrode for conducting electrons and allowing sodium ions to pass therethrough, and wherein electrons and sodium ions recombine to form sodium is positioned about the beta"-alumina solid electrolyte. The electrode is operated at a temperature and a pressure that allows the recombined sodium to vaporize. Additionally, an outer current collector grid for distributing electrons throughout the porous electrode is positioned about and contacts the porous electrode. Also included in the invention is transporting means for transporting liquid sodium to the beta"-alumina solid electrolyte of the tubular member. A transition piece is positioned about the interior of the member and contacts the transporting means. The transition piece divides the member into a first cell and a second cell such that each first and second cell has a beta"-alumina solid electrolyte, a first and second porous electrode and a grid. The transition piece conducts electrons from the interior of the tubular member. There is supply means for supplying sodium to the transporting means. Preferably the supply means is a shell which surrounds the tubular member and is operated at a temperature such that the vaporized sodium condenses thereon. Returning means for returning the condensed sodium from the shell to the transporting means provides a continuous supply of liquid sodium to the transporting means. Also, there are first conducting means for conducting electric current from the transition piece which extends through the shell, and second conducting means for conducting electric current to the grid of the first cell which extends through the shell.

Sievers, Robert K. (North Huntingdon, PA)

1989-01-01

316

Contemporary sample stacking in analytical electrophoresis.  

PubMed

Sample stacking is a term denoting a multifarious class of methods and their names that are used daily in CE for online concentration of diluted samples to enhance separation efficiency and sensitivity of analyses. The essence of these methods is that analytes present at low concentrations in a large injected sample zone are concentrated into a short and sharp zone (stack) in the separation capillary. Then the stacked analytes are separated and detected. Regardless of the diversity of the stacking electromigration methods, one can distinguish four main principles that form the bases of nearly all of them: (i) Kohlrausch adjustment of concentrations, (ii) pH step, (iii) micellar methods, and (iv) transient ITP. This contribution is a continuation of our previous reviews on the topic and brings an overview of papers published during 2010-2012 and relevant to the mentioned principles (except the last one which is covered by another review in this issue). PMID:23161176

Šlampová, Andrea; Malá, Zdena; Pant??ková, Pavla; Gebauer, Petr; Bo?ek, Petr

2012-12-03

317

40 CFR 61.33 - Stack sampling.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium § 61.33 Stack sampling. (a) Unless a waiver of emission testing is obtained under § 61.13,...

2013-07-01

318

Single-photon traversal of dielectric stacks  

Microsoft Academic Search

We examine single-photon bandgap traversal times. We see significant change in traversal times due to subtle differences in stack structures. We also analyze how propagation through inhomogeneous media affects Hong-Ou-Mandel visibility.

Natalia B. Rutter; Sergey V. Polyakov; Paul Lett; Alan Migdall

2009-01-01

319

40 CFR 61.53 - Stack sampling.  

Code of Federal Regulations, 2013 CFR

...POLLUTANTS National Emission Standard for Mercury § 61.53 Stack sampling. (a) Mercury ore processing facility. (1) Unless...61.13, each owner or operator processing mercury ore shall test emissions from the source...

2013-07-01

320

EEPROM memory stack with scaled down thickness  

Microsoft Academic Search

We studied OAO (oxide-?-Si-oxide) memory stacks of 450–600 Å total thickness that were part of multi-bit EEPROM elements. Information was stored in two isolated Poly\\/ralpha-Si floating gates located above the channel edges. The floating gate was 250–400 Å LPCVD amorphous Si or Poly, surrounded by 70 Å bottom oxide and 125 Å top oxide. Reliability of the new memory stack

Ruth Shima Edelstein; Chris Cork; Efraim Aloni; Nachi Vofsy; Yakov Roizin

2004-01-01

321

Cosmic ray test of INO RPC stack  

NASA Astrophysics Data System (ADS)

The India-based Neutrino Observatory (INO) collaboration is planning to build a 50 kt magnetised iron calorimeter (ICAL) detector using glass Resistive Plate Chambers (RPCs) as active detector elements. A stack of 12 such glass RPCs of 1 m ×1 m in area is tracking cosmic ray muons for over three years. In this paper, we will review the constructional aspects of the stack and discuss the performance of the RPCs using this cosmic ray data.

Bhuyan, M.; Datar, V. M.; Kalmani, S. D.; Lahamge, S. M.; Mondal, N. K.; Nagaraj, P.; Pal, S.; Reddy, L. V.; Redij, A.; Samuel, D.; Saraf, M. N.; Satyanarayana, B.; Shinde, R. R.; Verma, P.

2012-01-01

322

PAH emission from various industrial stacks  

Microsoft Academic Search

The emission of polycyclic aromatic hydrocarbons (PAHs) from various industrial stacks (blast furnace, basic oxygen furnace, coke oven, electric arc furnace, heavy oil plant, power plant and cement plant) in southern Taiwan were investigated. PAH concentrations (?g\\/N m3) and PAH emission factors (?g\\/kg feedstock) were determined. In addition to these eight stationary industrial stacks, an industrial waste incinerator, a diesel

Hsi-Hsien Yang; Wen-Jhy Lee; Shui-Jen Chen; Soon-Onn Lai

1998-01-01

323

Improvement of phosphoric acid fuel cell stacks  

Microsoft Academic Search

Phosphoric acid fuel cell components and stack assembly methods were evaluated. Electrodes with Pt loading between 0.3 and 0.9 g\\/sq. ft were employed. Matrix materials were phenolic (Kynol) fibers and SiC. A new ERC proprietary matrix was used also. Graphite bipolar plates with 33% phenolic resin binder were used. Stacks were tested on hydrogen and simulated reformed methanol for up

S. G. Abens; F. J. Ascenzo; B. S. Baker; G. Garretson; M. Lambrech

1980-01-01

324

Stack-based Typed Assembly Language  

Microsoft Academic Search

In previous work, we presented a Typed Assembly Language (TAL). TAL is sufficiently expressive to serve as a target language for compilers of high-level languages such as ML. This\\u000a work assumed such a compiler would perform a continuation-passing style transform and eliminate the control stack by heap-allocating activation records. However, most compilers are based on stack\\u000a allocation. This paper presents

Greg Morrisett; Karl Crary; Neal Glew; David Walker

325

Stack-Based Typed Assembly Language  

Microsoft Academic Search

. In previous work, we presented a Typed Assembly Language(TAL). TAL is su#ciently expressive to serve as a target language forcompilers of high-level languages such as ML. This work assumed such acompiler would perform a continuation-passing style transform and eliminatethe control stack by heap-allocating activation records. However,most compilers are based on stack allocation. This paper presents STAL,an extension of TAL

J. Gregory Morrisett; Karl Crary; Neal Glew; David Walker

1998-01-01

326

Stacking interactions in PUF?RNA complexes  

SciTech Connect

Stacking interactions between amino acids and bases are common in RNA-protein interactions. Many proteins that regulate mRNAs interact with single-stranded RNA elements in the 3' UTR (3'-untranslated region) of their targets. PUF proteins are exemplary. Here we focus on complexes formed between a Caenorhabditis elegans PUF protein, FBF, and its cognate RNAs. Stacking interactions are particularly prominent and involve every RNA base in the recognition element. To assess the contribution of stacking interactions to formation of the RNA-protein complex, we combine in vivo selection experiments with site-directed mutagenesis, biochemistry, and structural analysis. Our results reveal that the identities of stacking amino acids in FBF affect both the affinity and specificity of the RNA-protein interaction. Substitutions in amino acid side chains can restrict or broaden RNA specificity. We conclude that the identities of stacking residues are important in achieving the natural specificities of PUF proteins. Similarly, in PUF proteins engineered to bind new RNA sequences, the identity of stacking residues may contribute to 'target' versus 'off-target' interactions, and thus be an important consideration in the design of proteins with new specificities.

Yiling Koh, Yvonne; Wang, Yeming; Qiu, Chen; Opperman, Laura; Gross, Leah; Tanaka Hall, Traci M.; Wickens, Marvin (NIH); (UW)

2012-07-02

327

Influence of the ?-? interaction on the hydrogen bonding capacity of stacked DNA/RNA bases  

PubMed Central

The interplay between aromatic stacking and hydrogen bonding in nucleobases has been investigated via high-level quantum chemical calculations. The experimentally observed stacking arrangement between consecutive bases in DNA and RNA/DNA double helices is shown to enhance their hydrogen bonding ability as opposed to gas phase optimized complexes. This phenomenon results from more repulsive electrostatic interactions as is demonstrated in a model system of cytosine stacked offset-parallel with substituted benzenes. Therefore, the H-bonding capacity of the N3 and O2 atoms of cytosine increases linearly with the electrostatic repulsion between the stacked rings. The local hardness, a density functional theory-based reactivity descriptor, appears to be a key index associated with the molecular electrostatic potential (MEP) minima around H-bond accepting atoms, and is inversely proportional to the electrostatic interaction between stacked molecules. Finally, the MEP minima on surfaces around the bases in experimental structures of DNA and RNA–DNA double helices show that their hydrogen bonding capacity increases when taking more neighboring (intra-strand) stacking partners into account.

Mignon, Pierre; Loverix, Stefan; Steyaert, Jan; Geerlings, Paul

2005-01-01

328

Solid oxide fuel cell generator with removable modular fuel cell stack configurations  

DOEpatents

A high temperature solid oxide fuel cell generator produces electrical power from oxidation of hydrocarbon fuel gases such as natural gas, or conditioned fuel gases, such as carbon monoxide or hydrogen, with oxidant gases, such as air or oxygen. This electrochemical reaction occurs in a plurality of electrically connected solid oxide fuel cells bundled and arrayed in a unitary modular fuel cell stack disposed in a compartment in the generator container. The use of a unitary modular fuel cell stack in a generator is similar in concept to that of a removable battery. The fuel cell stack is provided in a pre-assembled self-supporting configuration where the fuel cells are mounted to a common structural base having surrounding side walls defining a chamber. Associated generator equipment may also be mounted to the fuel cell stack configuration to be integral therewith, such as a fuel and oxidant supply and distribution systems, fuel reformation systems, fuel cell support systems, combustion, exhaust and spent fuel recirculation systems, and the like. The pre-assembled self-supporting fuel cell stack arrangement allows for easier assembly, installation, maintenance, better structural support and longer life of the fuel cells contained in the fuel cell stack. 8 figs.

Gillett, J.E.; Dederer, J.T.; Zafred, P.R.; Collie, J.C.

1998-04-21

329

PCB levels and congener patterns from Korean municipal waste incinerator stack emissions  

Microsoft Academic Search

Congener specific polychlorinated biphenyl (PCB) data from the stack gas of nine Korean municipal waste incinerators was used to determine characteristic congener patterns of emitted PCBs. Principal component analysis revealed three classes of incinerators according to their pattern of PCB congener emissions: those resembling the background sampling material; those producing large quantities of a few tetra-chlorinated congeners; those producing large

M. G Ikonomou; P Sather; Jeong-Eun Oh; Won-Yong Choi; Yoon-Seok Chang

2002-01-01

330

Stack emissions from refuse?derived fuel admix to boiler coal  

Microsoft Academic Search

Emissions tests were run on a boiler fueled with coal and admixtures of fuel pellets prepared from solid wastes. The tests showed that use of the admixtures significantly lowered the sulfur dioxide and hydrocarbons in the stack gas while raising the lead emissions manyfold.

Jerry W. Jackson; Joe O. Ledbetter

1977-01-01

331

Method for inhibiting corrosion in particulate zinc  

SciTech Connect

A method is described for the inhibition of corrosion in particulate zinc, which comprises the step of subjecting said zinc in the form of an alkaline slurry to treatment by a corrosion inhibiting effective amount of a corrosion inhibitor which is at least one oxide selected from the group consisting of oxides of antimony, bismuth, cadmium, gallium, indium, lead, mercury, thallium and tin, wherein zinc has been obtained by an electrolytic process for regeneration of zinc in an at least partially spent slurry for use in metal-air batteries which slurry comprises an admixture of at least components (a) and (b), of the following components (a), (b), (c), (d), (e), (f) and (g): (a) zinc which has been at least partly oxidized to an oxidation product selected from zinc oxide and zincates; (b) an aqueous solution of at least one Group 1a metal comprising anions selected from the group consisting of hydroxide and zincate; (c) an inorganic inhibitor ingredient effective to inhibit an interaction of zinc and at least one Group 1a metal hydroxide in the aqueous solution, which would otherwise result in an evolution of hydrogen gas; (d) a gelling agent; (e) a filler selected from the group consisting of particulate and fibrous fillers; (f) a labelling agent; (g) a dissolved electrolyte extender.

Goldstein, J.; Meitav, A,; Lezion, R.; Kravitz, M.

1993-08-03

332

Stacking fault energy of iron-base shape memory alloys  

Microsoft Academic Search

The stacking fault energy of six iron-base shape memory alloys can be calculated by the extended dislocation node method. The results show that Ni and Mn increase the stacking fault energy of the alloys, while Cr and Si decrease the stacking fault energy. An expression relating the alloy elements Ni, Cr, Mn, and Si to the stacking fault energy of

J. C. Li; W. Zheng; Q. Jiang

1999-01-01

333

High Voltage Marx Generator Implementation using IGBT Stacks  

Microsoft Academic Search

High voltage Marx generator implementation using IGBT (Insulated Gate Bipolar Transistor) stacks is proposed in this paper. To protect the Marx generator at the moment of breakdown, AOCP (Active Over-Current Protection) part is included. The Marx generator is composed of 12 stages and each stage is made of IGBT stacks, two diode stacks, and capacitors. IGBT stack is used as

Jong-Hyun Kim; Byung-Duk Min; Sergey Shenderey; Geun-Hie Rim

2007-01-01

334

Primary particulate matter from ocean-going engines in the Southern California Air Basin.  

PubMed

The impact of primary fine particulate matter (PM2.5) from ship emissions within the Southern California Air Basin is quantified by comparing in-stack vanadium (V) and nickel (Ni) measurements from in-use ocean-going vessels (OGVs) with ambient measurements made at 10 monitoring stations throughout Southern California. V and Ni are demonstrated as robust markers for the combustion of heavy fuel oil in OGVs, and ambient measurements of fine particulate V and Ni within Southern California are shown to decrease inversely with increased distance from the ports of Los Angeles and Long Beach (ports). High levels of V and Ni were observed from in-stack emission measurements conducted on the propulsion engines of two different in-use OGVs. The in-stack V and Ni emission rates (g/h) normalized by the V and Ni contents in the fuel tested correlates with the stack total PM emission rates (g/h). The normalized emission rates are used to estimate the primary PM2.5 contributions from OGVs at 10 monitoring locations within Southern California. Primary PM2.5 contributions from OGVs were found to range from 8.8% of the total PM2.5 at the monitoring location closest to the port (West Long Beach) to 1.4% of the total PM2.5 at the monitoring location 80 km inland (Rubidoux). The calculated OGV contributions to ambient PM2.5 measurements at the 10 monitoring sites agree well with estimates developed using an emission inventory based regional model. Results of this analysis will be useful in determining the impacts of primary particulate emissions from OGVs upon worldwide communities downwind of port operations. PMID:19708372

Agrawal, Harshit; Eden, Rudy; Zhang, Xinqiu; Fine, Philip M; Katzenstein, Aaron; Miller, J Wayne; Ospital, Jean; Teffera, Solomon; Cocker, David R

2009-07-15

335

Radiative Heat Transfer in Combustion Applications: Parallel Efficiencies of Two Gas Models, Turbulent Radiation Interactions in Particulate Laden Flows, and Coarse Mesh Finite Difference Acceleration for Improved Temporal Accuracy  

NASA Astrophysics Data System (ADS)

We investigate several aspects of the numerical solution of the radiative transfer equation in the context of coal combustion: the parallel efficiency of two commonly-used opacity models, the sensitivity of turbulent radiation interaction (TRI) effects to the presence of coal particulate, and an improvement of the order of temporal convergence using the coarse mesh finite difference (CMFD) method. There are four opacity models commonly employed to evaluate the radiative transfer equation in combustion applications; line-by-line (LBL), multigroup, band, and global. Most of these models have been rigorously evaluated for serial computations of a spectrum of problem types [1]. Studies of these models for parallel computations [2] are limited. We assessed the performance of the Spectral-Line-Based weighted sum of gray gasses (SLW) model, a global method related to K-distribution methods [1], and the LBL model. The LBL model directly interpolates opacity information from large data tables. The LBL model outperforms the SLW model in almost all cases, as suggested by Wang et al. [3]. The SLW model, however, shows superior parallel scaling performance and a decreased sensitivity to load imbalancing, suggesting that for some problems, global methods such as the SLW model, could outperform the LBL model. Turbulent radiation interaction (TRI) effects are associated with the differences in the time scales of the fluid dynamic equations and the radiative transfer equations. Solving on the fluid dynamic time step size produces large changes in the radiation field over the time step. We have modified the statistically homogeneous, non-premixed flame problem of Deshmukh et al. [4] to include coal-type particulate. The addition of low mass loadings of particulate minimally impacts the TRI effects. Observed differences in the TRI effects from variations in the packing fractions and Stokes numbers are difficult to analyze because of the significant effect of variations in problem initialization. The TRI effects are very sensitive to the initialization of the turbulence in the system. The TRI parameters are somewhat sensitive to the treatment of particulate temperature and the particulate optical thickness, and this effect are amplified by increased particulate loading. Monte Carlo radiative heat transfer simulations of time-dependent combustion processes generally involve an explicit evaluation of emission source because of the expense of the transport solver. Recently, Park et al. [5] have applied quasi-diffusion with Monte Carlo in high energy density radiative transfer applications. We employ a Crank-Nicholson temporal integration scheme in conjunction with the coarse mesh finite difference (CMFD) method, in an effort to improve the temporal accuracy of the Monte Carlo solver. Our results show that this CMFD-CN method is an improvement over Monte Carlo with CMFD time-differenced via Backward Euler, and Implicit Monte Carlo [6] (IMC). The increase in accuracy involves very little increase in computational cost, and the figure of merit for the CMFD-CN scheme is greater than IMC.

Cleveland, Mathew A.

336

High strength particulate ceramics  

DOEpatents

This invention relates to new and useful hard, dense, composite materials made from metallic nitrides such as titanium nitride when combined with aluminum oxide and aluminum nitride and a process comprising the steps of: (1) mixing constituent materials using kerosene as a mixing medium; (2) screening, settling, filtering, and washing the mixture in acetone; (3) filling and sealing said materials in a latex mold; (4) isostatically pressing the material into a compacted powder; and (5) sintering the compacted powder in a gas atmosphere at 1,850.degree. C. for two hours.

Liles, Kenneth J. (Tuscaloosa, AL); Hoyer, Jesse L. (Tuscaloosa, AL); Mlynarski, Kenneth W. (Gambrills, MD)

1991-01-01

337

A novel optical scattering collection system for particulate monitoring applications  

SciTech Connect

Light collecting systems often require radically different optical surfaces than those commonly found in optical imaging systems. An optical particulate monitor must probe a volume in emission stacks to obtain a good statistical distribution of suspended particles. However, ideal imaging systems map object planes into conjugate image planes and can probe only small volumes. The authors describe the design, fabrication and performance of a novel optical scattering collection system that exploits precision-engineered reflective conical surfaces (axicons) in a telescopic arrangement that maps a line in object space onto the detector plane in image space. Such non-spherical surfaces are nearly impossible to fabricate using traditional methods, but can readily be made using the deterministic method of single-point diamond turning. In addition to complex optical surfaces, single-point diamond turning also makes possible the precision engineering of reference surfaces useful for built-in alignment of multiple surfaces and rapid assembly of the finished system.

Bernacki, B.E.; Miller, A.C. Jr. [Oak Ridge National Lab., TN (United States); Nuspliger, R.J. [Environmental Systems Corp., Knoxville, TN (United States)

1996-05-01

338

Inflatable containment diaphragm for sealing and removing stacks  

DOEpatents

A diaphragm with an inflatable torus-shaped perimeter is used to seal at least one end of a stack so that debris that might be hazardous will not be released during removal of the stack. A diaphragm is inserted and inflated in the lower portion of a stack just above where the stack is to be cut such that the perimeter of the diaphragm expands and forms a seal against the interior surface of the stack.

Meskanick, G.R.; Rosso, D.T.

1991-12-31

339

Prediction of a {1122} hcp stacking fault using a modified generalized stacking-fault calculation  

Microsoft Academic Search

We present a new approach for calculating generalized stacking-fault energies, which allows for in-plane relaxation of atoms. When applied to the {112} slip plane in hcp materials, our approach predicts that a stable stacking fault occurs, associated with a slip of 1\\/6 (11) ? ½ (c + a). This is consistent with the edge dislocation with b = (c +

J. R. Morris; J. Scharff; K. M. Ho; D. E. Turner; Y. Y. Ye; M. H. Yoo

1997-01-01

340

Technical description of Stack 296-B-5  

SciTech Connect

Of particular concern to facilities on the Hanford site is Title 40, Code of Federal Regulations, Chapter 40, Part 61, Subpart H, ``National emission Standards for Emissions of Radionuclides Other Than Radon From Department of Energy Facilities.`` Assessments of facility stacks and potential radionuclide emissions determined whether these stacks would be subject to the sampling and monitoring requirements of 40 CFR 61, Subpart H. Stack 296-B-5 exhausts 221-BB building which houses tanks containing B Plant steam condensate and B Plant process condensate from the operation of the low-level waste concentrator. The assessment of potential radionuclide emissions from the 296-B-5 stack resulted in an effective dose equivalent to the maximally exposed individual of less than 0.1 millirem per year. Therefore, the stack is not subject to the sampling and monitoring requirements of 40 CFR 61, Subpart H. However, the sampling and monitoring system must be in compliance with the Environmental Compliance Manual, WHC-CM-7-5. Currently, 296-B-5 is sampled continuously with a record sampler and continuous air monitor (CAM).

Ridge, T.M.

1994-11-15

341

Structure of Steady Particulate Seeded Plasma Flows Heated by a High Power Laser  

SciTech Connect

There is interest in efficient conversion of high power laser radiation into kinetic energy of a gas flow for some applications. Inverse Bremsstrahlung (IB) offers the advantage of spectral continuum absorption along with the rapid conversion of the absorbed energy into translational modes. However, IB is effective only when sufficient ionization is present. Hence, some mechanism must be operative at low temperatures to create and multiply an initial electron concentration. Seeding a gas flow with particulates is one such approach. Particulates absorb laser radiation and then thermally conduct heat to the surrounding gas. The effect of particulate seeding on the steady structure of ionized gas flows driven by a high power laser is investigated.

Mota, S.; Resendes, D.P.; Mendonca, J.T. [GoLP, Centro de Fisica de Plasmas, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisbon (Portugal)

2005-10-31

342

Environmental Pollution: Air Pollution - Particulate Matters.  

National Technical Information Service (NTIS)

This bibliography contains citations of reports dealing with air pollution - particulate matters; analysis of atmospheric aerosols and particulate matters, specifically particle size, measurement, distribution and identification of pollutants; atmos;heric...

1977-01-01

343

PAVED ROAD PARTICULATE EMISSIONS: SOURCE CATEGORY REPORT  

EPA Science Inventory

The report gives results of extensive field tests to develop emission factors for particulate emissions generated by traffic entrainment of paved road surface particulate matter. Using roadway surface silt loading as the basis, predictive emission factor equations for each partic...

344

PARTICULATE EMISSION MEASUREMENTS FROM CONTROLLED CONSTRUCTION ACTIVITIES  

EPA Science Inventory

The report summarized the results of field testing of the effectiveness of control measures for sources of fugitive particulate emissions found at construction sites. The effectiveness of watering temporary, unpaved travel surfaces on emissions of particulate matter with aerodyna...

345

Mobile Particulate Emission Studies of New York City Vehicles  

Microsoft Academic Search

Emissions from both diesel and gasoline powered motor vehicles are a significant source of urban particulate (PM2.5) and trace gas pollution. Emission characteriza- tions of motor vehicles are typically performed using a dynamometer. Few studies have been performed which characterize emissions from in-use vehicles using a mo- bile sampling platform. This work, which was part of the PM2.5 Technology Assess-

M. Canagaratna; J. Jayne; Q. Shi; C. E. Kolb; D. Worsnop

2002-01-01

346

Assessment of the 3420 Building Filtered Exhaust Stack Sampling Probe Location  

SciTech Connect

Pacific Northwest National Laboratory performed several tests in the exhaust air discharge from the new 3420 Building Filtered Exhaust Stack to determine whether the air sampling probe for emissions monitoring for radionuclides is acceptable. The method followed involved adopting the results of a previously performed test series from a system with a similar configuration, followed by several tests on the actual system to verify the applicability of the previously performed tests. The qualification criteria for these types of stacks include metrics concerning 1) uniformity of air velocity, 2) sufficiently small flow angle with respect to the axis of the duct, 3) uniformity of tracer gas concentration, and 4) uniformity tracer particle concentration.

Glissmeyer, John A.; Flaherty, Julia E.

2010-07-16

347

Assessment of the 3410 Building Filtered Exhaust Stack Sampling Probe Location  

SciTech Connect

Pacific Northwest National Laboratory performed several tests in the exhaust air discharge from the new 3410 Building Filtered Exhaust Stack to determine whether the air sampling probe for emissions monitoring for radionuclides is acceptable. The method followed involved adopting the results of a previously performed test series from a system with a similar configuration, followed by several tests on the actual system to verify the applicability of the previously performed tests. The qualification criteria for these types of stacks include metrics concerning 1) uniformity of air velocity, 2) sufficiently small flow angle with respect to the axis of the duct, 3) uniformity of tracer gas concentration, and 4) uniformity tracer particle concentration.

Glissmeyer, John A.; Flaherty, Julia E.

2010-07-16

348

Alternatives for high-temperature\\/high-pressure particulate control. Final report, October 1977October 1978  

Microsoft Academic Search

The report gives the status of the most promising high-temperature\\/high-pressure (HTP) particulate control devices being developed. Data are presented and anticipated performance and development problems are discussed. HTP particulate control offers efficiency and potential economic advantages over cold gas cleanup in pressurized fluidized-bed combustion (PFBC) and low-Btu coal gasification (LBCG) combined-cycle power generation systems. However, considerably more development will be

R. Parker; S. Calvert

1979-01-01

349

Characteristics of particulates emitted from a biomass fluidized-bed gasifier  

SciTech Connect

This paper presents the particulate emission data for feeding cotton-gin trash and cattle feedlot manure into a 0.3048 m fluidized-bed gasifier. This data can then be used to design the necessary cleaning apparatus depending on the type of end use for the low-energy gas. The particulate emissions vary from 172 g/m/sup 3/ for cotton-gin trash fly ash to 456 g/m/sup 3/ for cattle feedlot manure.

Datin, D.L.; Lepori, W.A.; Parnell, C.B.

1983-12-01

350

Process for particulate removal from coal liquids  

DOEpatents

Suspended solid particulates are removed from liquefied coal products by first subjecting such products to hydroclone action for removal in the underflow of the larger size particulates, and then subjecting the overflow from said hydroclone action, comprising the residual finer particulates, to an electrostatic field in an electrofilter wherein such finer particulates are deposited in the bed of beads of dielectric material on said filter. The beads are periodically cleaned by backwashing to remove the accumulated solids.

Rappe, Gerald C. (Macungie, PA)

1983-01-01

351

Conversion of SOâ to sulfur particulate in the Los Angeles atmosphere  

Microsoft Academic Search

Gas phase and particulate phase S were measured at various locations in the Los Angeles basin to determine atmospheric conversion rates and mechanisms. The aerosol S analyses were performed using a new aerosol vaporization technique, a modification of gas evolution analysis, which measures the total S mass in the aerosol of all S compounds which either vaporize or decompose at

P. T. Roberts; S. K. Friedlander

1975-01-01

352

Disproportionate impact of particulate emissions on global cloud condensation nuclei concentrations  

Microsoft Academic Search

Estimates of indirect aerosol radiative forcing have focused on increased sulfate aerosol mass concentrations caused by anthropogenic emissions of gas-phase sulfur dioxide, implicitly neglecting the impact of direct particulate emissions. Emissions of primary particles and gas-phase precursors have different effects on cloud condensation nuclei (CCN) concentrations as they impact CCN concentrations via different microphysical pathways. We present a theoretical analysis

P. J. Adams; J. H. Seinfeld

2003-01-01

353

40 CFR 63.7322 - What test methods and other procedures must I use to demonstrate initial compliance with the...  

Code of Federal Regulations, 2013 CFR

...CONTINUED) National Emission Standards for Hazardous...Quenching, and Battery Stacks Initial Compliance...initial compliance with the emission limits for particulate...Process weighted mass emissions of particulate matter...Volumetric flow rate of stack gas, dscf/hr;...

2013-07-01

354

Removal of SOx, NOx, and particulate from combusted carbonaceous fuels  

SciTech Connect

The invention is a method for removing sulfur oxides, nitrogen oxides and particulate from the products of combusted carbonaceous fuels. Sulfur oxides, nitrogen oxides and particulate are currently discharged to the atmosphere as flue gas in quantities highly detrimental to the environment. Potassium compounds, as are found in agricultural grade potash, are dispersed throughout the combustion products at the exit of the combustion zone of boilers. The potassium compounds decompose as a result of combustion temperatures in excess of their melting points. The potassium, as an ionic vapor, reacts with the sulfur and nitrogen oxide gases present, to form potassium sulfates, potassium nitrites and potassium nitrates. When the combined products stream, traversing the boiler equipment train, cool sufficiently, the potassium, present in excess, condenses as potassium oxide on the surfaces of the particles present. The larger particles are removed from the non-condensed vapor and gas by the centrifugal and gravitational forces exerted within cyclones. The smaller particles are removed from the non-chargable vapor and gases by the electrostatic charge and attraction created within the precipitator. The dry particles discharged from the cyclones and precipitator are ready for ultimate end use as potash fertilizer without further treatment. The flue gas atmospheric emissions contain only trace quantities of sulfur oxides, nitrogen oxides and particulate.

Dayen, W.R.

1985-09-10

355

Nonlinear effects in particulate processes  

Microsoft Academic Search

The nonlinear effects in various particulate processes are analyzed within the context of population balance modeling. Our main objective is to indicate the origin of the nonlinear effects and to categorize them in a systematic manner. To illustrate the importance of the nonlinear effects, a continuous milling process is considered, which has been analyzed in the literature with linear population

E. Bilgili; B. Scarlett

2005-01-01

356

Turbine Engine Particulate Emission Characterization.  

National Technical Information Service (NTIS)

Particulate emissions from the TF-30, JT8D, and JT9D aircraft turbine engines were characterized for mass emission rate, particle size distribution, particle shape, and elemental composition as a function of engine type, fuel type, and power setting. Samp...

D. L. Fenton E. H. Luebcke J. D. Stockham P. B. Campbell R. H. Johnson

1979-01-01

357

Monitoring of particulate matter outdoors  

Microsoft Academic Search

Recent studies of the size and composition of atmospheric particulate matter (PM) have demonstrated the usefulness of separating atmospheric PM into its fine and coarse components. The need to measure the mass and composition of fine and coarse PM separately has been emphasized by research in exposure, epidemiology, and toxicology of atmospheric PM. This paper provides a background on the

W. E. Wilson; Judith C. Chow; Candis Claiborn; Wei Fusheng; Johann Engelbrecht; John G. Watson

2002-01-01

358

Source Testing for Particulate Matter.  

ERIC Educational Resources Information Center

|Developed for presentation at the 12th Conference on Methods in Air Pollution and Industrial Hygiene Studies, University of Southern California, April, 1971, this outline covers procedures for the testing of particulate matter. These are: (1) basic requirements, (2) information required, (3) collection of samples, (4) processing of samples, (5)…

DeVorkin, Howard

359

MONITORING OF PARTICULATE MATTER OUTDOORS  

EPA Science Inventory

Recent studies of the size and composition of atmospheric particulate matter (PM) have demonstrated the usefulness of separating atmospheric PM into its fine and coarse components. The need to measure the mass and composition of fine and coarse PM separately has been emphasized b...

360

Advanced Fine Particulate Characterization Methods  

Microsoft Academic Search

The characterization and control of emissions from combustion sources are of significant importance in improving local and regional air quality. Such emissions include fine particulate matter, organic carbon compounds, and NO and SO gases, along with mercury and other toxic metals. This project involved four activities including Further Development of Analytical Techniques for PM and PM{sub 2.5} Characterization and Source

Steven Benson; Lingbu Kong; Alexander Azenkeng; Jason Laumb; Robert Jensen; Edwin Olson; Jill MacKenzie; A. M. Rokanuzzaman

2007-01-01

361

UV PRE-IONIZED RAIL-GAP SWITCH FOR STACKED BLUMLEIN PULSE GENERATORS*  

SciTech Connect

Stacked Blumlein Pulse Generators comprised of parallel-plate transmission lines are potentially a useful pulse-power architecture for high-gradient, compact, electron-beam accelerators and other applications. Such pulse generators require a low-inductance, fast (<5ns) switch per stage to erect the stack and produce the desired output pulse. We are developing a rail-gap switch tightly integrated with the stack for this application. We employ ultraviolet light (UV) to pre-ionize the switch, which facilitates prompt, low-jitter, and potentially multichannel operation. A novel aspect of our switch is that the source of the UV is a conventional Xenon flashlamp. This allows variation of the switch pressure and gas without affecting the flashlamp operation. We can operate our switch in either triggered or self-breaking mode. Here we present initial results of a two-stage, stacked Blumlein operating in self-break mode. We compare the switch performance to gas-switch scaling laws with respect to resistive-phase risetime and trigger delay as a function of gas density, gap-length, and gap-voltage.

Rhodes, M A

2005-05-09

362

Cross-flow filter-sorbent catalyst for particulate, SO sub 2 and NO sub x control  

SciTech Connect

This report describes a new concept for integrated pollutant control: a cross-flow filter comprised of layered, gas permeable membranes that act a particulate filter, an SO{sub 2} sorbent, and a NO{sub x} reduction catalyst.

Not Available

1990-05-01

363

Cross-flow, filter-sorbent catalyst for particulate, SO sub 2 and NO sub x control  

SciTech Connect

This report describes a new concept for integrated pollutant control: a cross-flow filter comprised of layered, gas permeable membranes that act a particulate filter, an SO{sub 2} sorbent, and a NO{sub x} reduction catalyst.

Benedek, K. (Little (Arthur D.), Inc., Cambridge, MA (United States)); Flytzani-Stephanopoulos, M. (Massachusetts Inst. of Tech., Cambridge, MA (United States))

1991-08-01

364

Particulate Matter — What is the Standard?  

Microsoft Academic Search

A concentrated effort to examine and lower the amount of emissions of particulate matter into the atmosphere is occur- ring. It is important to consider how to best address this area. An examination of ongoing work and its relationship to particulate requirements is the focus of this paper. The studies are dependent on the definition of particulate matter. A focus

A. M. Hartstein; F. D. Sutterfield; D. Gurney

1998-01-01

365

Particulate emissions from concentrated animal feeding operations  

Technology Transfer Automated Retrieval System (TEKTRAN)

Concentrated animal feeding operations (CAFOs), including open beef cattle feedlots, swine facilities, and poultry facilities, can emit large amounts of particulate matter, including TSP (total suspended particulates), PM10 (particulate matter with equivalent aerodynamic diameter of 10 mm or less) a...

366

Coherent emission of light using stacked gratings  

NASA Astrophysics Data System (ADS)

The possibility of temporally and spatially coherent thermal emission has been demonstrated utilizing stacked gratings. We demonstrate that the metallic grating with narrow air slit behaves like a homogeneous slab with large permittivity and small permeability and find that the interaction between the metallic grating and the Bragg grating gives rise to impendence matching at wavelengths located in the photonic band gap of the Bragg grating, which enables the stacked gratings to perform high emission with ultranarrow spectrum and antenna-like spatial response. This paves the way towards the design of a novel infrared source platform for applications such as thermal analysis, imaging, security, biosensing, and medical diagnoses.

Gong, Yongkang; Liu, Xianliang; Li, Kang; Huang, Jungang; Martinez, J. J.; Rees-Whippey, Daniel; Carver, Sara; Wang, Leiran; Zhang, Wenfu; Duan, Tao; Copner, Nigel

2013-05-01

367

Three wafer stacking for 3D integration.  

SciTech Connect

Vertical wafer stacking will enable a wide variety of new system architectures by enabling the integration of dissimilar technologies in one small form factor package. With this LDRD, we explored the combination of processes and integration techniques required to achieve stacking of three or more layers. The specific topics that we investigated include design and layout of a reticle set for use as a process development vehicle, through silicon via formation, bonding media, wafer thinning, dielectric deposition for via isolation on the wafer backside, and pad formation.

Greth, K. Douglas; Ford, Christine L.; Lantz, Jeffrey W.; Shinde, Subhash L.; Timon, Robert P.; Bauer, Todd M.; Hetherington, Dale Laird; Sanchez, Carlos Anthony

2011-11-01

368

Method and apparatus for transport, introduction, atomization and excitation of emission spectrum for quantitative analysis of high temperature gas sample streams containing vapor and particulates without degradation of sample stream temperature  

DOEpatents

A sample transport, sample introduction, and flame excitation system for spectrometric analysis of high temperature gas streams which eliminates degradation of the sample stream by condensation losses.

Eckels, David E. (Ankeny, IA); Hass, William J. (Ames, IA)

1989-05-30

369

The Morgantown Energy Technology Center`s particulate cleanup program  

SciTech Connect

The development of integrated gasification combined cycle (IGCC) and pressurized fluidized-bed combustion (PFBC) power systems has made it possible to use coal while still protecting the environment. Such power systems significantly reduce the pollutants associated with coal-fired plants built before the 1970s. This superior environmental performance and related high system efficiency is possible, in part, because particulate gas-stream cleanup is conducted at high-temperature and high-pressure process conditions. A main objective of the Particulate Cleanup Program at the Morgantown Energy Technology Center (METC) is to ensure the success of the CCT demonstration projects. METC`s Particulate Cleanup Program supports research, development, and demonstration in three areas: (1) filter-system development, (2) barrier-filter component development, and (3) ash and char characterization. The support is through contracted research, cooperative agreements, Cooperative Research And Development Agreements (CRADAs), and METC`s own in-house research. This paper describes METC`s Particulate Cleanup Program.

Dennis, R.A.

1995-12-01

370

Pressurized Testing of Solid Oxide Electrolysis Stacks with Advanced Electrode-Supported Cells  

SciTech Connect

A new facility has been developed at the Idaho National Laboratory for pressurized testing of solid oxide electrolysis stacks. Pressurized operation is envisioned for large-scale hydrogen production plants, yielding higher overall efficiencies when the hydrogen product is to be delivered at elevated pressure for tank storage or pipelines. Pressurized operation also supports higher mass flow rates of the process gases with smaller components. The test stand can accommodate cell dimensions up to 8.5 cm x 8.5 cm and stacks of up to 25 cells. The pressure boundary for these tests is a water-cooled spool-piece pressure vessel designed for operation up to 5 MPa. The stack is internally manifolded and operates in cross-flow with an inverted-U flow pattern. Feed-throughs for gas inlets/outlets, power, and instrumentation are all located in the bottom flange. The entire spool piece, with the exception of the bottom flange, can be lifted to allow access to the internal furnace and test fixture. Lifting is accomplished with a motorized threaded drive mechanism attached to a rigid structural frame. Stack mechanical compression is accomplished using springs that are located inside of the pressure boundary, but outside of the hot zone. Initial stack heatup and performance characterization occurs at ambient pressure followed by lowering and sealing of the pressure vessel and subsequent pressurization. Pressure equalization between the anode and cathode sides of the cells and the stack surroundings is ensured by combining all of the process gases downstream of the stack. Steady pressure is maintained by means of a backpressure regulator and a digital pressure controller. A full description of the pressurized test apparatus is provided in this paper.

J. E. O'Brien; X. Zhang; G. K. Housley; K. DeWall; L. Moore-McAteer; G. Tao

2012-06-01

371

Properties of Ag layered in Te/Cd stack prepared by stacked elemental layer method  

NASA Astrophysics Data System (ADS)

Ag layered Te/Cd stack thin films (<1 µm thick) were prepared by the Stacked Elemental Layer (SEL) method. The XRD results revealed that the synthesized films had a polycrystalline nature. The synthesized films were preferentially oriented with (111) directions with a cubic phase. Structural studies were evidenced the formation of Ag related alloys at high annealing temperatures as a result of thermal diffusion in elemental stack. Optical and photo-resistivity studies revealed the influence of Ag on the CdTe lattice at high annealing temperatures. Surface morphology and the influence of Ag atoms on surface roughness are also presented.

Subramani, Shanmugan; Devarajan, Mutharasu; Ibrahim, Kamarulazizi

2012-06-01

372

Asymmetrical reverse vortex flow due to induced-charge electro-osmosis around carbon stacking structures  

NASA Astrophysics Data System (ADS)

Broken symmetry of vortices due to induced-charge electro-osmosis (ICEO) around stacking structures is important for the generation of a large net flow in a microchannel. Following theoretical predictions in our previous study, we herein report experimental observations of asymmetrical reverse vortex flows around stacking structures of carbon posts with a large height (~110 ?m) in water, prepared by the pyrolysis of a photoresist film in a reducing gas. Further, by the use of a coupled calculation method that considers boundary effects precisely, the experimental results, except for the problem of anomalous flow reversal, are successfully explained. That is, unlike previous predictions, the precise calculations here show that stacking structures accelerate a reverse flow rather than suppressing it for a microfluidic channel because of the deformation of electric fields near the stacking portions; these structures can also generate a large net flow theoretically in the direction opposite that of a previous prediction for a standard vortex flow. Furthermore, by solving the one-dimensional Poisson-Nernst-Plank (PNP) equations in the presence of ac electric fields, we find that the anomalous flow reversal occurs by the phase retardation between the induced diffuse charge and the tangential electric field. In addition, we successfully explain the nonlinearity of the flow velocity on the applied voltage by the PNP analysis. In the future, we expect to improve the pumping performance significantly by using stacking structures of conductive posts along with a low-cost process.

Sugioka, Hideyuki

2011-05-01

373

SRS reactor stack plume marking tests  

SciTech Connect

Tests performed in 105-K in 1987 and 1988 demonstrated that the stack plume can successfully be made visible (i.e., marked) by introducing smoke into the stack breech. The ultimate objective of these tests is to provide a means during an emergency evacuation so that an evacuee can readily identify the stack plume and evacuate in the opposite direction, thus minimizing the potential of severe radiation exposure. The EPA has also requested DOE to arrange for more tests to settle a technical question involving the correct calculation of stack downwash. New test canisters were received in 1988 designed to produce more smoke per unit time; however, these canisters have not been evaluated, because normal ventilation conditions have not been reestablished in K Area. Meanwhile, both the authorization and procedure to conduct the tests have expired. The tests can be performed during normal reactor operation. It is recommended that appropriate authorization and procedure approval be obtained to resume testing after K Area restart.

Petry, S.F.

1992-03-01

374

The stacking-fault energy of graphite  

Microsoft Academic Search

Stacking-fault energies can be obtained from electron transmission micrographs by two methods. The first, due to Whelan (1958), involves measurement of the radius of curvature of a partial dislocation at an extended node. The interaction of the various partial dislocations at the measuring point is neglected and the value to be taken for the line tension of the partial dislocation

C. Baker; Y. T. Chou; A. Kelly

1961-01-01

375

49 CFR 178.980 - Stacking test.  

Code of Federal Regulations, 2012 CFR

...qualification of all Large Packagings design types intended to be stacked...except flexible Large Packaging design types must be loaded to their...test must be conducted at room temperature on an empty, unsealed...compression testing. (e) Criterion for passing the test....

2012-10-01

376

49 CFR 178.980 - Stacking test.  

Code of Federal Regulations, 2011 CFR

...qualification of all Large Packagings design types intended to be stacked...except flexible Large Packaging design types must be loaded to their...test must be conducted at room temperature on an empty, unsealed...compression testing. (e) Criterion for passing the test....

2011-10-01

377

The Location Stack: Multisensor Fusion in Action  

Microsoft Academic Search

The Location Stack is a set of design abstractions and sensor fusion techniques for location systems. It employs novel probabilistic techniques such as particle filters to fuse readings from multiple sensor technologies while providing a uniform programming interface to applications. Our implementation is publicly available and supports many location sensor technologies. Specifically, our live demonstration tracks multiple people using statistical

Jeffrey Hightower; Gaetano Borriello

378

Stacking in sediments of colloidal hard spheres.  

PubMed

We use computer simulations to investigate the crystallization dynamics of sedimenting hard spheres in large systems (hundreds of thousands of particles). We show that slow sedimentation results primarily in face-centered cubic (fcc) stacked crystals, instead of random hexagonal close packed or hexagonal close packed (hcp) crystals. We also find slanted stacking faults, in the fcc regions. However, we attribute the formation of fcc to the free energy difference between fcc and hcp and not to the presence of these slanted stacking faults. Although the free energy difference between hcp and fcc per particle is small (only 10(-3) times the thermal energy), it can become considerable, when multiplied by the number of particles in each domain. The ratio of fcc to hcp obtained from dynamic simulations is in excellent agreement with well-equilibrated Monte Carlo simulations, in which no slanted stacking faults were found. Our results explain a range of experiments on colloids, in which the amount of fcc increases upon lowering the sedimentation rate or decreasing the initial volume fraction. PMID:21787016

Marechal, Matthieu; Hermes, Michiel; Dijkstra, Marjolein

2011-07-21

379

Average Transmission Probability of a Random Stack  

ERIC Educational Resources Information Center

|The transmission through a stack of identical slabs that are separated by gaps with random widths is usually treated by calculating the average of the logarithm of the transmission probability. We show how to calculate the average of the transmission probability itself with the aid of a recurrence relation and derive analytical upper and lower…

Lu, Yin; Miniatura, Christian; Englert, Berthold-Georg

2010-01-01

380

Arrays of stacked metal coordination compounds  

DOEpatents

A process is disclosed for preparing novel arrays of metal coordination compounds characterized by arrangement of the metal ions, separated by a linking agent, in stacked order one above the other. The process permits great flexibility in the design of the array. For example, layers of different composition can be added to the array at will. 3 figs.

Bulkowski, J.E.

1986-10-21

381

Arrays of stacked metal coordination compounds  

DOEpatents

A process is disclosed for preparing novel arrays of metal coordination compounds characterized by arrangement of the metal ions, separated by a linking agent, in stacked order one above the other. The process permits great flexibility in the design of the array. For example, layers of different composition can be added to the array at will.

Bulkowski, John E. (Newark, DE)

1986-01-01

382

Nonlinearly Stacked Low Noise Turbofan Stator.  

National Technical Information Service (NTIS)

The present invention provides a nonlinearly stacked low noise turbofan stator vane. The stator is in an axial fan or compressor turbomachinery stage that is comprised of a collection of vanes whose highly three-dimensional shape is selected to reduce rot...

D. S. Weir J. A. Gunara K. B. Kontos N. A. Nolcheff W. B. Schuster

2005-01-01

383

Locating Interoperability in the Network Stack  

Microsoft Academic Search

The conventional view within the Internet community is that IP is the appropriate basis for interoperability in the network stack. However, recent developments in IP networking and link layer technologies that cannot be supported by the IP standard have increased the pressure towards creating non-interoperable network domains. In this paper we explore one avenue of attack on these problems, using

Micah Beck; Terry Moore

2004-01-01

384

Harry Stack Sullivan's “Expert in interpersonal relations”  

Microsoft Academic Search

Harry Stack Sullivan died some twenty years ago, in 1949, but his influence upon the behavioral sciences continues to be felt. Both his way of practicing psychiatry and his theories of personality, for example, serve as continuing reminders that we cannot look at a patient as someone who carries a disease around inside him, but as one whose problems and

John Patton

1970-01-01

385

Long Duration Balloon Data Acquisition Stack Upgrade  

Microsoft Academic Search

The Long Duration Balloon Data Acquisition Stack (LDB DAQ) has not been updated since earlier in this decade. It is desired to replace obsolete or unavailable components and redesign for modern applications. This includes the combination of two conventional LDB DAQ decks, the Timed Command Deck (TCMD) and the Housekeeping Deck (HSK) into one Telemetry Deck. The CSBF CAP II

Jacob Gilbert

2008-01-01

386

Aromatic stacking interactions in flavin model systems.  

PubMed

Flavins feature multiple attributes that explain their widespread occurrence in nature, including photostability, reversible electrochemistry, and especially the tunability of their optical, electronic, and redox properties by supramolecular interactions and modification of their chemical structure. Flavins are important redox cofactors for enzymatic catalysis and are central to a wide variety of processes, including biosynthesis, electron transport, photosynthesis, and DNA repair. The wide range of processes catalyzed by flavins makes them promising leads for synthetic catalysts. Their properties are also relevant to organic electronic and optoelectronic devices, where they have the potential to serve as photoactive electron carriers, a very uncommon property in current photovoltaic systems. In flavoenzymes, the flavin cofactor binds to the active site of the apoenzyme through noncovalent interactions. These interactions regulate cofactor recognition and tune the redox behavior of the flavin cofactor. In this Account, we describe the creation of host-guest systems based on small molecule, polymer, and nanoparticle scaffolds that explore the role of aromatic stacking on the redox properties of the flavin and provide insight into flavoenzyme function. We also describe the creation of synthetic flavin-based interlocked structures featuring aromatic stacking interactions, along with the use of aromatic stacking to direct self-assembly of flavin-based materials. The interplay between redox events and aromatic stacking interactions seen in these synthetic models is important for fundamental understanding of biological systems including the flavoenzymes. The precise control of aromatic interactions and binding of flavins not only underpins their biological activity but gives them the potential to be developed into novel organic optoelectronic materials based on tuned synthetic flavin-receptor assemblies. In a broader context, the redox properties of the flavin provide a very concise tool for looking at the role of electronics in aromatic stacking, an issue of general importance in biological and supramolecular chemistry. PMID:23163808

Nandwana, Vikas; Samuel, Ifor; Cooke, Graeme; Rotello, Vincent M

2012-11-19

387

TEST RESULTS OF HIGH TEMPERATURE STEAM/CO2 CO-ELECTROLYSIS IN A 10-CELL STACK  

SciTech Connect

High temperature coelectrolysis experiments with CO2 / H2O mixtures were performed in a 10-cell planar solid oxide stack. Results indicated that stack apparent ASR values were shown not to vary significantly between pure steam electrolysis and steam / CO2 coelectrolysis values. Product gas compositions measured via an online micro gas chromatograph (GC) showed excellent agreement to predictions obtained from a chemical equilibrium coelectrolysis model developed for this study. Experimentally determined open cell potentials and thermal neutral voltages for coelectrolysis compared favorably to predictions obtained from a chemical equilibrium coelectrolysis and energy balance model, also developed for this study.

James E. O'Brien; Joseph J. Hartvigsen

2007-06-01

388

Effect of nitrogen on generalized stacking fault energy and stacking fault widths in high nitrogen steels  

Microsoft Academic Search

We use a generalized Peierls–Nabarro model fitted to generalized stacking fault energies (GSFE) calculated from ab initio density functional theory to study the effect of interstitial nitrogen content on stacking faults (SF) in {111} plane of face-centered cubic (fcc) Fe–N alloys. These simplified systems are reliable representatives of fcc Fe–Mn–N steels, for example, as Mn acts to stabilize fcc relative

S. Kibey; J. B. Liu; M. J. Curtis; D. D. Johnson; H. Sehitoglu

2006-01-01

389

FEASIBILITY OF A STACK INTEGRATED SOFC OPTICAL CHEMICAL SENSOR  

SciTech Connect

The work performed during the UCR Innovative Concepts phase I program was designed to demonstrate the chemical sensing capabilities of nano-cermet SPR bands at solid oxide fuel cell operating conditions. Key to this proposal is that the materials choice used a YSZ ceramic matrix which upon successful demonstration of this concept, will allow integration directly onto the SOFC stack. Under the Innovative Concepts Program the University at Albany Institute for Materials (UAIM)/UAlbany School of NanoSciences and NanoEngineering synthesized, analyzed and tested Pa, and Au doped YSZ nano-cermets as a function of operating temperature and target gas exposure (hydrogen, carbon monoxide and 1-dodecanethiol). During the aforementioned testing procedure the optical characteristics of the nano-cermets were monitored to determine the sensor selectivity and sensitivity.

Michael A. Carpenter

2004-03-30

390

3D CFD Model of a Multi-Cell High Temperature Electrolysis Stack  

SciTech Connect

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis stack performance and steam electrolysis in the Idaho National Laboratory Integrated Lab Scale (ILS) experiment. The model is made of 60 planar cells stacked on top of each other operated as Solid Oxide Electrolysis Cells (SOEC). Details of the model geometry are specific to a stack that was fabricated by Ceramatec, Inc1. and tested at the Idaho National Laboratory. Inlet and outlet plenum flow and distribution are considered. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT2. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC userdefined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, activation overpotential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Variations in flow distribution, and species concentration are discussed. End effects of flow and per-cell voltage are also considered.

G.L. Hawkes; J. E. O'Brien; C. M. Stoots

2007-11-01

391

3-D CFD MODEL OF A MULTI-CELL HIGH TEMPERATURE ELECTROLYSIS STACK  

SciTech Connect

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis stack performance and steam electrolysis in the Idaho National Laboratory (INL) Integrated Lab Scale (ILS) experiment. The model is made of 60 planar cells stacked on top of each other operated as Solid Oxide Electrolysis Cells (SOEC). Details of the model geometry are specific to a stack that was fabricated by Ceramatec, Inc. and tested at INL. Inlet and outlet plenum flow and distribution are considered. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, activation over-potential, anode-side gas composition, cathode-side gas composition, current density, and hydrogen production over a range of stack operating conditions. Variations in flow distribution and species concentration are discussed. End effects of flow and per-cell voltage are also considered.

Grant Hawkes; James O'Brien; Carl Stoots; Brian Hawkes

2009-05-01

392

For Study of Infrared Techniques for Monitoring Stack Gases.  

National Technical Information Service (NTIS)

Infrared spectral study of industrial stack plumes was performed to investigate the feasibility of pollution efflux monitoring by remote observation. The conclusions of this study are: (1) Measurement of industrial stack pollution rates is feasible with s...

J. M. Lepper

1965-01-01

393

DEVSML 2.0: The Language and the Stack.  

National Technical Information Service (NTIS)

This paper presents a revised version of DEVSML stack. The earlier version introduced the concept of transparent simulators in a netcentric domain. This version of DEVSML 2.0 stack introduces the transparent modeling concept and how a platform independent...

S. Mittal S. A. Douglas

2012-01-01

394

VIEW OF STACK WITH AUTOMOBILE AND TRACTOR REPAIR SHOP TO ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF STACK WITH AUTOMOBILE AND TRACTOR REPAIR SHOP TO THE FAR RIGHT. WAREHOUSE WITH ITS RIDGELINE ROTARY VENTS TO RIGHT OF STACK. VIEW FROM THE WEST - Kekaha Sugar Company, Sugar Mill Building, 8315 Kekaha Road, Kekaha, Kauai County, HI

395

Project W-420 Stack Monitoring system upgrades conceptual design report  

SciTech Connect

This document describes the scope, justification, conceptual design, and performance of Project W-420 stack monitoring system upgrades on six NESHAP-designated, Hanford Tank Farms ventilation exhaust stacks.

TUCK, J.A.

1998-11-06

396

43. VIEW NORTHWEST OF WOODEN STACK ON CONNECTOR BETWEEN BUILDINGS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

43. VIEW NORTHWEST OF WOODEN STACK ON CONNECTOR BETWEEN BUILDINGS 49 AND 41; STACK VENTED CORROSIVE FUMES FROM DIPPING OPERATIONS IN BUILDING 49A - Scovill Brass Works, 59 Mill Street, Waterbury, New Haven County, CT

397

Development of a particulate control Cyclocentrifuge. Phase II: laboratory tests. Monthly technical progress report No. 19, January 1978February 1978. Attachment A. Control of alkali metals in low Btu turbine fuel gas using a Cyclocentrifuge  

Microsoft Academic Search

Attachment ''A'' of this report has specific recommendations. The Cyclocentrifuge feasibility report showed that the baseline combined-cycle electric power system can be altered to fire 1000°F low BTU fuel gas, rather than low BTU gas at te baseline temperature of 1550°F, and that this temperature reduction can be accomplished without a significant change in the cost per kilowatt hour. The

J. T. McCabe; W. Garber; P. Albrecht

1978-01-01

398

Experimental study on the influence of the porosity of parallel plate stack on the temperature decrease of a thermoacoustic refrigerator  

NASA Astrophysics Data System (ADS)

Thermoacoustic refrigerators are cooling devices which are environmentally friendly because they don't use hazardous gases like chlorofuorocarbons (CFCs) or hydrofuorocarbons (HFCs) but rather air or inert gases as working medium. They apply sound wave with high intensity to pump heat from the cold to hot the regions through a stack in a resonator tube. One of the important parameters of thermoacoustic refrigerators is the porosity (blockage ratio) of stack which is a fraction of cross sectional area of the resonator unblocked for the gas movement by the stack. This paper describes an experimental study on how the porosity of parallel plate stack affects the temperature decrease of a thermoacoustic refrigerator. The porosity of parallel plate stack is specified by the thickness of plates and the spacing between plates. We measured the maximum temperature decreases of thermacoustic refrigerator using stacks with various porosities in the range of 0.5 - 0.85, with plate spacing from 0.5 mm to 1.5 mm and plate thicknesses 0.3 mm, 0.4 mm, and 0.5 mm. The measurements were done with two resonators with length of 0.8 m and 1.0 m, with air at atmospheric pressure and room temperature, correspond to thermal penetration depths (??) of 0.26 mm and 0.29 mm, respectively. It was found that there is an optimum porosity which gives the largest temperature decreases, and there is a tendency that the optimum porosity shifts to a larger value and the temperature decrease become larger when we used a stack with thinner plates. On the other hand, the study on the dependence of the temperature decrease on the plate thickness and the plate spacing reveals more useful information than that on the stack porosity itself. We found that stack with thinner plates tends to give larger temperature decrease, and the plate spacing of around 4?? leads to the largest temperature decrease.

Setiawan, Ikhsan; Bambang Setio Utomo, Agung; Mitrayana; Katsuta, Masafumi; Nohtomi, Makoto

2013-04-01

399

Precision of manual measurement techniques for metal stack gas emissions  

Microsoft Academic Search

Test results are affected by temporal and spatial variability, process fluctuations, sampling team and laboratory vagaries and techniques, as well as the inherent characteristics of the test method. These errors all affect measurements generated during multi-run compliance test results. Overall measurement variability is made up of process variability which describes the expected emissions range after removing the effect of measurement

H. Gregor Rigo; A. John Chandler

2000-01-01

400

A thermodynamic model for the stacking-fault energy  

Microsoft Academic Search

A general thermodynamic model for calculating the energy of stacking faults is presented and applied to f.c.c. Fe–Cr–Ni alloys. A distinction is made between ideal stacking faults and real stacking faults which are associated with an ideal stacking-fault energy (SFE) and an effective SFE, respectively. The ideal SFE is characterized by a chemical energy volume term and an interphase surface

P. J. Ferreira; P. Muellner

1998-01-01

401

Space plasma physics: isotopic stack: measurement of heavy cosmic rays.  

PubMed

A stack of plastic nuclear track detectors was exposed to heavy cosmic rays on the pallet of Spacelab 1. Some layers of the stack were rotated with respect to the main stack to determine the arrival time of the particles. After return of the stack the latent particle tracks are revealed by chemical etching. Under the optical microscope the charge, mass, energy, and impact direction of the particles can be deduced from the track geometry. PMID:17837938

Beaujean, R; Schmidt, M; Enge, W; Siegmon, G; Krause, J; Fischer, E

1984-07-13

402

Preliminary evaluation of the gaseous effluent sampling and monitoring systems at the 291-Z-1 and 296-Z-3 stacks. Plutonium finishing facility  

SciTech Connect

The 291-Z-1 and 296-Z-3 stack effluent particulate sampling and monitoring systems are being evaluated for compliance with Atlantic Richfield Hanford Company`s Interim Criteria for such systems. This evaluation is part of a study by Battelle-Northwest of gaseous effluent sampling systems in ARHCO facilities. This letter report presents a preliminary evaluation of the mentioned facilities and the indicated improvements needed to meet the Interim Criteria so that conceptual design work for improved systems can be initiated. There is currently underway a detailed study at the two stacks including a series of sampling experiments, the findings of which will not be included in this report. The gaseous effluent sampling system at the 291-Z-1 and 296-Z-3 stacks are very dissimilar and will be treated in separate sections of this report. The discussions for each sampling system will include a brief description and a preliminary evaluation of the systems.

Schwendiman, L.C.; Glissmeyer, J.A.

1992-04-01

403

Container stacking control and simulations: Difference between cranes and railcars  

Microsoft Academic Search

Stacking schedule has become more and more important for container terminal operation, especially for automatic marine container terminals. It is studied by minimize the total work done by transportation, and lower the average stack height. The stacking slot is optimized in two kinds of operation mechanisms, cranes and railcars. The simulation result obtained by iterative method shows the difference between

Xiao-qian Zhang; Lu Wang; Dao-yuan Zhou

2010-01-01

404

Scale dependant compensational stacking of channelized sedimentary deposits  

Microsoft Academic Search

Compensational stacking, the tendency for sediment transport system to preferentially fill topographic lows, thus smoothing out topographic relief is a concept used in the interpretation of the stratigraphic record. Recently, a metric was developed to quantify the strength of compensation in sedimentary basins by comparing observed stacking patterns to what would be expected from simple, uncorrelated stacking. This method uses

Y. Wang; K. M. Straub; E. A. Hajek

2010-01-01

405

A reconsideration of the measurements with the O ring stack  

SciTech Connect

The measurements made this year of Rn entry to the O ring stack were interpreted to be diffusion through the urethane O rings; however the alternative hypothesis is that Rn was mainly entering the stack by leakage through a small hole. This note presents a calculation of diffusion from first principles and rederives the diffusion constant for the O ring stack measurements.

Cleveland, B. T.; Rowley, J.K.

1996-09-01

406

40 CFR 52.1532 - Stack height review.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height review. 52.1532 Section 52.1532... New Hampshire § 52.1532 Stack height review. The State of New Hampshire...limitations have been affected by stack height credits greater than good...

2013-07-01

407

40 CFR 52.2633 - Stack height regulations.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height regulations. 52.2633 Section 52...CONTINUED) Wyoming § 52.2633 Stack height regulations. In a letter dated...the State committed to conduct stack height evaluations in accordance with...

2013-07-01

408

40 CFR 51.164 - Stack height procedures.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height procedures. 51.164 Section 51...and Modifications § 51.164 Stack height procedures. Such procedures must...affected by so much of any source's stack height that exceeds good engineering...

2013-07-01

409

40 CFR 52.2347 - Stack height regulations.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height regulations. 52.2347 Section...CONTINUED) Utah § 52.2347 Stack height regulations. The State of Utah has committed to revise its stack height regulations should EPA complete...

2013-07-01

410

40 CFR 52.1388 - Stack height regulations.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height regulations. 52.1388 Section...CONTINUED) Montana § 52.1388 Stack height regulations. The State of Montana has committed to revise its stack height regulations should EPA complete...

2013-07-01

411

40 CFR 52.1034 - Stack height review.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height review. 52.1034 Section 52.1034...CONTINUED) Maine § 52.1034 Stack height review. The State of Maine has declared...limitations have been affected by stack height credits greater than good...

2013-07-01

412

40 CFR 51.118 - Stack height provisions.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height provisions. 51.118 Section 51... Control Strategy § 51.118 Stack height provisions. (a) The plan must...affected by so much of any source's stack height that exceeds good engineering...

2013-07-01

413

40 CFR 52.383 - Stack height review.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height review. 52.383 Section 52.383...PLANS Connecticut § 52.383 Stack height review. The State of Connecticut...limitations have been affected by stack height credits greater than good...

2013-07-01

414

40 CFR 52.2085 - Stack height review.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height review. 52.2085 Section 52.2085... Rhode Island § 52.2085 Stack height review. The State of Rhode Island...limitations have been affected by stack height credits greater than good...

2013-07-01

415

40 CFR 52.1169 - Stack height review.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height review. 52.1169 Section 52.1169... Massachusetts § 52.1169 Stack height review. The Commonwealth of Massachusetts...limitations have been affected by stack height credits greater than good...

2013-07-01

416

40 CFR 52.2534 - Stack height review.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height review. 52.2534 Section 52.2534... West Virginia § 52.2534 Stack height review. The State of West Virginia...power plant, have been affected by stack height credits greater than good...

2013-07-01

417

40 CFR 52.2384 - Stack height review.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height review. 52.2384 Section 52.2384...CONTINUED) Vermont § 52.2384 Stack height review. The State of Vermont has...limitations have been affected by stack height credits greater than good...

2013-07-01

418

40 CFR 52.345 - Stack height regulations.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height regulations. 52.345 Section...PLANS Colorado § 52.345 Stack height regulations. The State of Colorado has committed to revise its stack height regulations should EPA complete...

2013-07-01

419

40 CFR 52.2180 - Stack height regulations.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height regulations. 52.2180 Section...South Dakota § 52.2180 Stack height regulations. The State of South Dakota has committed to revise its stack height regulations should EPA complete...

2013-07-01

420

40 CFR 52.1832 - Stack height regulations.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Stack height regulations. 52.1832 Section...North Dakota § 52.1832 Stack height regulations. The State of North Dakota has committed to revise its stack height regulations should EPA complete...

2013-07-01

421

A simple machine simulator for teaching stack frames  

Microsoft Academic Search

Stack frames are a fundamental concept in computer science often taught in an operating systems or an assembly language programming course. Computer security courses also rely on an understanding of stack frame concepts when teaching buffer overflow attacks. To assist students in learning the fundamentals of stack frames and related concepts, we have developed an interactive Simple Machine Simulator tool

Dino Schweitzer; Jeff Boleng

2010-01-01

422

Implementing Stack Simulation for Highly-Associative Memories  

Microsoft Academic Search

Prior to this work, all implementations of stack simulation [MGS70] required more than linear time to process an address trace. In particular these implementations are often slow for highly-associative memories and traces with poor locality, as can be found in simulations of tile systems. We describe a new implementation of stack simulation where the refrrenced block and its stack distance

Yul H. Kim; Mark D. Hill; David A. Wood

1991-01-01

423

A Stack-Based Resource Allocation Policy for Realtime Processes  

Microsoft Academic Search

The Stack Resource Policy (SRP) is a resource allocation policy which permits processes with different priorities to share a single runtime stack. It is a refinement of the Priority Ceiling Protocol (PCP) of Sha, Rajkumar and Lehoczky, which strictly bounds priority inversion and permits simple schedulability tests. With or without stack sharing, the SRP offers im- provements over the PCP,

Theodore P. Baker

1990-01-01

424

Attachment method for stacked integrated circuit (IC) chips  

Microsoft Academic Search

An attachment method for stacked integrated circuit (IC) chips is disclosed. The method involves connecting stacked chips, such as DRAM memory chips, to each other and\\/or to a circuit board. Pads on the individual chips are rerouted to form pads on the side of the chip, after which the chips are stacked on top of each other whereby desired interconnections

A. F. Bernhardt; V. Malba

1999-01-01

425

GENERAL VIEW OF REMAINS OF STACK NO. 1 LOOKING NORTHEAST ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

GENERAL VIEW OF REMAINS OF STACK NO. 1 LOOKING NORTHEAST SHOWING WEST PORTAL, WITH PROFILE OF STACK NO. 2 AT LEFT - Greenwood Furnace, Stack No. 1, East of McAlevy's Fort on State Route 305, McAlevys Fort, Huntingdon County, PA

426

Bolling AFB Stack Emission Evaluation Bolling AFB DC.  

National Technical Information Service (NTIS)

This report presents the results of particulate emission testing done on a single oil fired steam boiler at Bolling AFB, Washington DC. Testing was done at three different heat input loadings as requested by the Washington District Commission. Particulate...

M. L. Sweigart

1975-01-01

427

40 CFR 75.72 - Determination of NOX mass emissions for common stack and multiple stack configurations.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Determination of NOX mass emissions for common stack and multiple... CONTINUOUS EMISSION MONITORING NOX Mass Emissions Provisions § 75.72 Determination of NOX mass emissions for common stack and...

2010-07-01

428

Annular feed air breathing fuel cell stack  

DOEpatents

A stack of polymer electrolyte fuel cells is formed from a plurality of unit cells where each unit cell includes fuel cell components defining a periphery and distributed along a common axis, where the fuel cell components include a polymer electrolyte membrane, an anode and a cathode contacting opposite sides of the membrane, and fuel and oxygen flow fields contacting the anode and the cathode, respectively, wherein the components define an annular region therethrough along the axis. A fuel distribution manifold within the annular region is connected to deliver fuel to the fuel flow field in each of the unit cells. In a particular embodiment, a single bolt through the annular region clamps the unit cells together. In another embodiment, separator plates between individual unit cells have an extended radial dimension to function as cooling fins for maintaining the operating temperature of the fuel cell stack.

Wilson, Mahlon S. (Los Alamos, NM)

1996-01-01

429

Long Duration Balloon Data Acquisition Stack Upgrade  

NASA Astrophysics Data System (ADS)

The Long Duration Balloon Data Acquisition Stack (LDB DAQ) has not been updated since earlier in this decade. It is desired to replace obsolete or unavailable components and redesign for modern applications. This includes the combination of two conventional LDB DAQ decks, the Timed Command Deck (TCMD) and the Housekeeping Deck (HSK) into one Telemetry Deck. The CSBF CAP II telemetry module has the desired functionality however it is not in the proper physical package to be of use with the rest of the DAS Stack decks. This paper will describe the repackaging operation in terms of hardware, both components and layout. The firmware running on the Altera FPGA should need no update since the hardware will have the exact same physical functionality as the CAP II telemetry module.

Gilbert, Jacob

430

IRM Enforcement of Java Stack Inspection  

Microsoft Academic Search

Two implementations are given for Java's stack-inspection access- control policy. Each implementation is obtained by generating an in- lined reference monitor (IRM) for a dieren t formulation of the policy. Performance of the implementations is evaluated, and one is found to be competitive with Java's less-exible, JVM-resident implementation. The exercise illustrates the power of the IRM approach for enforcing security

Úlfar Erlingsson; Fred B. Schneider

2000-01-01

431

Multiple stack quantum dot infrared photodetectors  

NASA Astrophysics Data System (ADS)

Quantum dot infrared photodetectors (QDIP) have established themselves as promising devices for detecting infrared (IR) radiation for wavelengths <20?m due to their sensitivity to normal incidence radiation and long excited carrier lifetimes. A limiting factor of QDIPs at present is their relatively small absorption volume, leading to a lower quantum efficiency and detectivity than in quantum well infrared photodetectors and mercury cadmium telluride based detectors. One means of increasing the absorption volume is to incorporate a greater number of quantum dot (QD) stacks, thereby increasing the probability of photon capture. Growth of InAs/InGaAs dot-in-a-well (DWELL) QDIPs with greater than 10 stacks is challenging due to the increased strain between layers, leading to high dark current. It is known that strain can be reduced in QDIPs by reducing the width of the InGaAs well and incorporating a second well consisting of GaAs and barriers consisting of AlGaAs. A number of InAs/InGaAs/GaAs DWELL QDIPs with 30-80 stacks have been grown, fabricated and characterised. Dark current in these layers appears to be constant at given electric field, suggesting strain does not increase significantly if the number of QD stacks is increased. IR spectral measurements show well defined peaks at 5.5?m, 6.5?m and 8.4?m. In this work a comparison between dark current, noise, gain, responsivity and detectivity in these layers is presented and compared to existing data from conventional DWELL QDIPs.

Vines, P.; Tan, C. H.; David, J. P. R.; Attaluri, R. S.; Vandervelde, T. E.; Krishna, S.

2008-10-01

432

Fast beam stacking using rf barriers  

SciTech Connect

Two barrier RF systems were fabricated, tested and installed in the Fermilab Main Injector. Each can provide 8 kV rectangular pulses (the RF barriers) at 90 kHz. When a stationary barrier is combined with a moving barrier, injected beams from the Booster can be continuously deflected, folded and stacked in the Main Injector, which leads to doubling of the beam intensity. This paper gives a report on the beam experiment using this novel technology.

Chou, W.; Capista, D.; Griffin, J.; Ng, K.-Y.; Wildman, D.; /Fermilab

2007-06-01

433

IAS Stacking Library in IDL (Bethermin+, 2010)  

NASA Astrophysics Data System (ADS)

Number counts reach 35uJy, 3.5mJy and 40mJy at 24um, 70um, and 160um, respectively. We reach deeper flux densities of 0.38mJy at 70, and 3.1 at 160um with a stacking analysis. Products (point spread function, counts, CIB, contributions, software) are publicly available for download at http://www.ias.u-psud.fr/irgalaxies/ (2 data files).

Bethermin, M.; Dole, H.; Beelen, A.; Aussel, H.

2010-04-01

434

The stacking-fault energy of nickel  

Microsoft Academic Search

The weak-beam method of electron microscopy has been used to study dis sociated edge dislocations and faulted dipoles in nickel. Micrographs have been compared with many-beam computed image profiles to deduce values for the dimensions of the defects, and these results are then used in conjunction with anisotropic elasticity theory to obtain the stacking-fault energy, ?, or an upper limit,

C. B. Carter; S. M. Holmes

1977-01-01

435

Subsea BOP stack built for Caspian drilling  

SciTech Connect

This paper reports that Shaffer Inc. completed construction of a multi-million dollar subsea drilling system for Caspmorneftegas, an operating company in the Republic of Azerbaijan. The subsea stack will be installed on the semisubmersible drilling rig Shelf 7 currently under construction in Astrakan in the Soviet Union. Shelf 7 will drill wells in the Caspian Sea, one of the most prolific production areas in the Soviet Union.

Not Available

1991-12-16

436

CAM and stack air sampler design guide  

SciTech Connect

About 128 air samplers and CAMs presently in service to detect and document potential radioactive release from `H` and `F` area tank farm ventilation stacks are scheduled for replacement and/or upgrade by Projects S-5764, S-2081, S-3603, and S-4516. The seven CAMs scheduled to be upgraded by Project S-4516 during 1995 are expected to provide valuable experience for the three remaining projects. The attached document provides design guidance for the standardized High Level Waste air sampling system.

Phillips, T.D.

1994-05-13

437

Thyristor stack for pulsed inductive plasma generation.  

PubMed

A thyristor stack for pulsed inductive plasma generation has been developed and tested. The stack design includes a free wheeling diode assembly for current reversal. Triggering of the device is achieved by a high side biased, self supplied gate driver unit using gating energy derived from a local snubber network. The structure guarantees a hard firing gate pulse for the required high dI/dt application. A single fiber optic command is needed to achieve a simultaneous turn on of the thyristors. The stack assembly is used for switching a series resonant circuit with a ringing frequency of 30 kHz. In the prototype pulsed power system described here an inductive discharge has been generated with a pulse duration of 120 micros and a pulse energy of 50 J. A maximum power transfer efficiency of 84% and a peak power of 480 kW inside the discharge were achieved. System tests were performed with a purely inductive load and an inductively generated plasma acting as a load through transformer action at a voltage level of 4.1 kV, a peak current of 5 kA, and a current switching rate of 1 kA/micros. PMID:19334940

Teske, C; Jacoby, J; Schweizer, W; Wiechula, J

2009-03-01

438

Thyristor stack for pulsed inductive plasma generation  

NASA Astrophysics Data System (ADS)

A thyristor stack for pulsed inductive plasma generation has been developed and tested. The stack design includes a free wheeling diode assembly for current reversal. Triggering of the device is achieved by a high side biased, self supplied gate driver unit using gating energy derived from a local snubber network. The structure guarantees a hard firing gate pulse for the required high dI/dt application. A single fiber optic command is needed to achieve a simultaneous turn on of the thyristors. The stack assembly is used for switching a series resonant circuit with a ringing frequency of 30 kHz. In the prototype pulsed power system described here an inductive discharge has been generated with a pulse duration of 120 ?s and a pulse energy of 50 J. A maximum power transfer efficiency of 84% and a peak power of 480 kW inside the discharge were achieved. System tests were performed with a purely inductive load and an inductively generated plasma acting as a load through transformer action at a voltage level of 4.1 kV, a peak current of 5 kA, and a current switching rate of 1 kA/?s.

Teske, C.; Jacoby, J.; Schweizer, W.; Wiechula, J.

2009-03-01

439

Chemical mechanical planarization of multilayer dielectric stacks  

NASA Astrophysics Data System (ADS)

Sub-0.5 micrometers multilevel metal schemes impose stringent requirements on both gap-fill and planarity of interlevel dielectrics. A variety of novel materials and processes are being investigated to meet these process requirements. In this paper, four dielectrics with good gap- filling capabilities are evaluated for planarity characteristics: SiO2 deposited using a high density plasma (HDP) with simultaneous deposition and sputtering, an organic spin-on-glass material SOG-A, an inorganic spin-on-glass material SOG-B, and SiO2 deposited using ozone and TEOS at sub-atmospheric pressure (SACVD). These materials are used for gap-fill followed by a capping layer of PETEOS. For global planarization, only the top layer of PETEOS is planarized using chemical mechanical polishing (CMP) without exposing the underlying gap-fill material. Planarization characteristics of the dielectric stacks are found to be significantly different, both before and after CMP. The CMP throughput is found to be very sensitive to the choice of the dielectric stack. For a given planarity goal, the CMP throughputs of three of the dielectric stacks are found to be significantly higher than that of a conventional single layer interlevel dielectric (ILD) consisting of only PETEOS.

Jain, Manoj K.; Dixit, Girish A.; Chisholm, Michael F.; Seha, Thomas R.; Taylor, Kelly J.; Shinn, Gregory B.; Havemann, Robert H.

1994-09-01

440

DEVELOPMENT OF COMPUTER MODULES OF PARTICULATE PROCESSES FOR REGIONAL PARTICULATE MODEL  

EPA Science Inventory

The development of an aerosol model for inclusion in the EPA Regional Particulate Model is described. Existing computer modules of particulate processes developed under EPA contract by Professors Brock, Seinfeld, and Whitby are compared to determine efficient and accurate methods...

441

Particulate Air Pollution and Morbidity in the California Central Valley: A High Particulate Pollution Region.  

National Technical Information Service (NTIS)

The purpose of this study was to evaluate the relationship between particulate air pollution and morbidity among the Kaiser Permanente (KP) membership who reside in the Central Valley (CV) of California. Daily augmented particulate matter (PM) monitoring ...

S. K. Van Den Eeden C. P. Quesenberry J. Shan F. Lurmann

2002-01-01

442

4 kW Test of Solid Oxide Electrolysis Stacks with Advanced Electrode-Supported Cells  

SciTech Connect

A new test stand has been developed at the Idaho National Laboratory for multi-kW testing of solid oxide electrolysis stacks. This test stand will initially be operated at the 4 KW scale. The 4 kW tests will include two 60-cell stacks operating in parallel in a single hot zone. The stacks are internally manifolded with an inverted-U flow pattern and an active area of 100 cm2 per cell. Process gases to and from the two stacks are distributed from common inlet/outlet tubing using a custom base manifold unit that also serves as the bottom current collector plate. The solid oxide cells incorporate a negative-electrode-supported multi-layer design with nickel-zirconia cermet negative electrodes, thin-film yttria-stabilized zirconia electrolytes, and multi-layer lanthanum ferrite-based positive electrodes. Treated metallic interconnects with integral flow channels separate the cells and electrode gases. Sealing is accomplished with compliant mica-glass seals. A spring-loaded test fixture is used for mechanical stack compression. Due to the power level and the large number of cells in the hot zone, process gas flow rates are high and heat recuperation is required to preheat the cold inlet gases upstream of the furnace. Heat recuperation is achieved by means of two inconel tube-in-tube counter-flow heat exchangers. A current density of 0.3 A/cm2 will be used for these tests, resulting in a hydrogen production rate of 25 NL/min. Inlet steam flow rates will be set to achieve a steam utilization value of 50%. The 4 kW test will be performed for a minimum duration of 1000 hours in order to document the long-term durability of the stacks. Details of the test apparatus and initial results will be provided.

J. E. O'Brien; X. Zhang; G. K. Housley; L. Moore-McAteer; G. Tao

2012-06-01

443

Tunable band gap in biased rhombohedral-stacked trilayer graphene  

NASA Astrophysics Data System (ADS)

We have employed dispersion-corrected density-functional calculations to investigate the electronic characteristics of Bernal-stacked trilayer (ABA) and rhombohedral-stacked (ABC) trilayer graphene. In contrast to semimetallic behavior for Bernal-stacked trilayer, rhombohedral-stacked trilayer leads to a band gap opening with the applications of a perpendicular electric bias. The induced gap is shown to be attributed to the avoiding of level crossing among even and odd parity states that depends on the stacking pattern. The tunable band gap suggests a sensitive and effective way to tailor properties of trilayer graphene for future applications in nanoscale devices.

Mihiri Shashikala, H. B.; Wang, Xiao-Qian

2012-03-01

444

Imaging Stacking Order in Few-Layer Graphene  

SciTech Connect

Few-layer graphene (FLG) has been predicted to exist in various crystallographic stacking sequences, which can strongly influence the material's electronic properties. We demonstrate an accurate and efficient method to characterize stacking order in FLG using the distinctive features of the Raman 2D-mode. Raman imaging allows us to visualize directly the spatial distribution of Bernal (ABA) and rhombohedral (ABC) stacking in tri- and tetralayer graphene. We find that 15% of exfoliated graphene tri- and tetralayers is composed of micrometer-sized domains of rhombohedral stacking, rather than of usual Bernal stacking. These domains are stable and remain unchanged for temperatures exceeding 800 C.

C Lui; Z Li; Z Chen; P Klimov; L Brus; T Heinz

2011-12-31

445

Methods of separating particulate residue streams  

SciTech Connect

A particulate residue separator and a method for separating a particulate residue stream may include an air plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams that are formed by the harvesting device and that travel, at least in part, along the air plenum and in a direction of the second, exhaust end; and a baffle assembly that is located in partially occluding relation relative to the air plenum and that substantially separates the first and second particulate residue air streams.

Hoskinson, Reed L. (Rigby, ID); Kenney, Kevin L. (Idaho Falls, ID); Wright, Christopher T. (Idaho Falls, ID); Hess, J. Richard (Idaho Falls, ID)

2011-04-05

446

Electrically heated particulate filter using catalyst striping  

DOEpatents

An exhaust system that processes exhaust generated by an engine is provided. The system generally includes a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine. A grid of electrically resistive material is applied to an exterior upstream surface of the PF and selectively heats exhaust passing through the grid to initiate combustion of particulates within the PF. A catalyst coating is applied to the PF that increases a temperature of the combustion of the particulates within the PF.

Gonze, Eugene V; Paratore, Jr., Michael J; Ament, Frank

2013-07-16

447

Mercury Control With The Advanced Hybrid Particulate Collector  

SciTech Connect

This project was awarded under U.S. Department of Energy (DOE) National Energy Technology Laboratory Program Solicitation DE-FC26-01NT41184 and specifically addresses Technical Topical Area 4 - Testing Novel and Less Mature Control Technologies on Actual Flue Gas at the Pilot Scale. The project team included the Energy & Environmental Research Center as the main contractor; W.L. Gore & Associates, Inc., as a technical and financial partner; and the Big Stone Plant operated by Otter Tail Power Company, host for the field-testing portion of the research. Since 1995, DOE has supported development of a new concept in particulate control called the advanced hybrid particulate collector (AHPC). The AHPC has been licensed to W.L. Gore and Associates, Inc., and is marketed as the Advanced Hybrid{trademark} filter by Gore. The AHPC combines the best features of electrostatic precipitators (ESPs) and baghouses in a unique configuration, providing major synergism between the two collection methods, both in the particulate collection step and in the transfer of dust to the hopper. The AHPC provides ultrahigh collection efficiency, overcoming the problem of excessive fine-particle emissions with conventional ESPs, and it solves the problem of reentrainment and re-collection of dust in conventional baghouses. The AHPC also appears to have unique advantages for mercury control over baghouses or ESPs as an excellent gas--solid contactor. The objective of the original five-task project was to demonstrate 90% total mercury control in the AHPC at a lower cost than current mercury control estimates. The approach included benchscale batch tests, larger-scale pilot testing with real flue gas on a coal-fired combustion system, and field demonstration at the 2.5-MW scale at a utility power plant to prove scale-up and demonstrate longer-term mercury control. The scope of work was modified to include an additional sixth task, initiated in April 2003. The objective of this task was to evaluate the mercury capture effectiveness of the AHPC when used with elemental mercury oxidation additives. This project, which is now in the final report phase, demonstrated at the pilot-scale level a technology that provides a cost-effective technique to control mercury and, at the same time, greatly enhances fine particulate collection efficiency. The technology can be used to retrofit systems currently employing inefficient ESP technology as well as for new construction, thereby providing a solution for improved fine particulate control combined with effective mercury control for a large segment of the U.S. utility industry as well as other industries.

Stanley J. Miller; Ye Zhuang; Jay C. Almlie

2004-12-31

448

40 CFR 60.1845 - What records must I keep for stack tests?  

Code of Federal Regulations, 2013 CFR

...records must I keep for stack tests? 60.1845...STATIONARY SOURCES Emission Guidelines and Compliance...records must I keep for stack tests? For stack...control device during all stack tests for dioxins/furans emissions. (d) The...

2013-07-01

449

Measuring Particulate Emissions from Autos  

NSDL National Science Digital Library

This learning activity from the Advanced Technology Environmental and Energy Center (ATEEC) is intended to help environmental science or biology students connect a real-world problem to the application of math, science, technical and critical thinking knowledge and skill concepts; the lesson specifically focuses on particulate emissions from automobiles and their impact on air pollution. The activity should take about one class period to complete (plus time for students to complete analysis outside of class), and requires a few easily obtainable materials. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.

Willey, Babe

2011-03-10

450

Final Report - MEA and Stack Durability for PEM Fuel Cells  

SciTech Connect

Proton exchange membrane fuel cells are expected to change the landscape of power generation over the next ten years. For this to be realized one of the most significant challenges to be met for stationary systems is lifetime, where 40,000 hours of operation with less than 10% decay is desired. This project conducted fundamental studies on the durability of membrane electrode assemblies (MEAs) and fuel cell stack systems with the expectation that knowledge gained from this project will be applied toward the design and manufacture of MEAs and stack systems to meet DOE’s 2010 stationary fuel cell stack systems targets. The focus of this project was PEM fuel cell durability – understanding the issues that limit MEA and fuel cell system lifetime, developing mitigation strategies to address the lifetime issues and demonstration of the effectiveness of the mitigation strategies by system testing. To that end, several discoveries were made that contributed to the fundamental understanding of MEA degradation mechanisms. (1) The classically held belief that membrane degradation is solely due to end-group “unzipping” is incorrect; there are other functional groups present in the ionomer that are susceptible to chemical attack. (2) The rate of membrane degradation can be greatly slowed or possibly eliminated through the use of additives that scavenge peroxide or peroxyl radicals. (3) Characterization of GDL using dry gases is incorrect due to the fact that fuel cells operate utilizing humidified gases. The proper characterization method involves using wet gas streams and measuring capillary pressure as demonstrated in this project. (4) Not all Platinum on carbon catalysts are created equally – the major factor impacting catalyst durability is the type of carbon used as the support. (5) System operating conditions have a significant impact of lifetime – the lifetime was increased by an order of magnitude by changing the load profile while all other variables remain the same. (6) Through the use of statistical lifetime analysis methods, it is possible to develop new MEAs with predicted durability approaching the DOE 2010 targets. (7) A segmented cell was developed that extend the resolution from ~ 40 to 121 segments for a 50cm2 active area single cell which allowed for more precise investigation of the local phenomena in a operating fuel cell. (8) The single cell concept was extended to a fuel size stack to allow the first of its kind monitoring and mapping of an operational fuel cell stack. An internal check used during this project involved evaluating the manufacturability of any new MEA component. If a more durable MEA component was developed in the lab, but could not be scaled-up to ‘high speed, high volume manufacturing’, then that component was not selected for the final MEA-fuel cell system demonstration. It is the intent of the team to commercialize new products developed under this project, but commercialization can not occur if the manufacture of said new components is difficult or if the price is significantly greater than existing products as to make the new components not cost competitive. Thus, the end result of this project is the creation of MEA and fuel cell system technology that is capable of meeting the DOEs 2010 target of 40,000 hours for stationary fuel cell systems (although this lifetime has not been demonstrated in laboratory or field testing yet) at a cost that is economically viable for the developing fuel cell industry. We have demonstrated over 2,000 hours of run time for the MEA and system developed under this project.

Yandrasits, Michael A.

2008-02-15

451

Year-round records of gas and particulate carboxylic acids (formate and acetate) in the boundary layer at Dumont d'Urville (coastal Antarctica): Production of carboxylic acids from biogenic NMHC emissions from the Antarctic ocean  

NASA Astrophysics Data System (ADS)

Multiple year-round concentrations of acetic and formic acids were measured both in gas and aerosol phases at Dumont d'Urville (DDU, a coastal Antarctic site: 66^o40'S, 140^o01'E) by using mist chamber and aerosol filter sampling. Aerosol levels of the 2 carboxylates range from less than one ng m-3 in winter to 5--10 ng m-3 in summer. Comparison with gas phase concentrations shows that almost 99% of the 2 carboxylic acids are present in the gas phase. Concentrations of formic acid in the gas phase are minima in June--July (70 ng m-3) and increase regularly towards summer months when levels reach ˜400 ng m-3. Concentrations of acetic acid in the gas phase exhibit a more well-marked seasonal cycle with values remaining close to 50 ng m-3 from April to October and strongly increase during summer months (mean value of 800 ng m-3). Such a strong seasonal cycle of carboxylic acids in the high southern latitude marine boundary layer displays with observations made at numerous continental sites where a more weak seasonality is generally observed. It is suggested that carboxylic acids present at DDU mainly originate from biogenic emissions from the Antarctic ocean which are expected to closely follow annual cycle of the sea ice extent and solar radiation, affecting in particular photochemical production of alkenes from dissolved organic carbon released from phytoplancton. Summer levels of carboxylic acids are discussed in terms of air-sea fluxes of NMHCs and photochemical production of carboxylic acids from ozone-alkene reactions and HO_2 reaction with peroxyacetal radical in these poor NOx environments.

Legrand, M.; Preunkert, S.; Jourdain, B.

2003-04-01

452

40 CFR 60.1815 - How do I monitor the temperature of flue gases at the inlet of my particulate matter control device?  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false How do I monitor the temperature of flue gases at the inlet of my particulate... § 60.1815 How do I monitor the temperature of flue gases at the inlet of my particulate...a device to continuously measure the temperature of the flue gas stream at the inlet...

2013-07-01

453

40 CFR 60.1325 - How do I monitor the temperature of flue gases at the inlet of my particulate matter control device?  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false How do I monitor the temperature of flue gases at the inlet of my particulate... § 60.1325 How do I monitor the temperature of flue gases at the inlet of my particulate...a device to continuously measure the temperature of the flue gas stream at the inlet...

2013-07-01

454

40 CFR 62.15270 - How do I monitor the temperature of flue gases at the inlet of my particulate matter control device?  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false How do I monitor the temperature of flue gases at the inlet of my particulate... § 62.15270 How do I monitor the temperature of flue gases at the inlet of my particulate...a device to continuously measure the temperature of the flue gas stream at the inlet...

2013-07-01

455

Method and apparatus for the separation of a gas-solids mixture in a circulating fluidized bed reactor  

DOEpatents

The system of the present invention includes a centripetal cyclone for separating particulate material from a particulate laden gas solids stream. The cyclone includes a housing defining a conduit extending between an upstream inlet and a downstream outlet. In operation, when a particulate laden gas-solids stream passes through the upstream housing inlet, the particulate laden gas-solids stream is directed through the conduit and at least a portion of the solids in the particulate laden gas-solids stream are subjected to a centripetal force within the conduit.

Vimalchand, Pannalal (Birmingham, AL); Liu, Guohai (Birmingham, AL); Peng, WanWang (Birmingham, AL)

2010-08-10

456

Control of NOx and particulate emissions from spreader-stokers fired with hogged wood  

SciTech Connect

The formation and emission of nitrogen oxides and particulate carry-over were studied from spreader-stoker combustion of nogged Douglas-fir, with a focus on optimizing the combustion conditions in each of the two distinct combustion zones, the bed phase and the suspension phase. Local oxygen availability was the controlling parameter for nitric oxide formation. Minimum nitric oxide emissions were found when local air: fuel stoichiometric ratios were held at 0.70-0.85, with emissions reduced as much as 39%. Long first-stage residence times allowed intermediate nitrogenous species to decay to molecular nitrogen, if there was sufficient oxygen for first-stage formation of nitric oxide. Entrainment of large particulates was a function of furnace gas velocities in the bed zone. Operation of the furnace at low stoichiometric ratios (fuel rich) in the bed zone reduced these gas velocities and thus reduced particulate emissions. (Refs. 12).

Munro, J.M.; Bradshaw, F.W.; Pershing, D.W.

1987-06-01

457

Southern Fine Particulate Monitoring Project  

SciTech Connect

This final project report presents experimental details, results and analysis of continuous onsite ambient fine particulate data at the North Birmingham sampling site during the October, 2001-September, 2002 study period.The host site for these measurement activities is the North Birmingham PM monitoring station by the Jefferson County Health Department in Birmingham, AL.The continuous data include PM{sub 2.5} mass concentrations measured by TEOM, particle sulfate using the R&P 8400S monitor, particle size distributions measured by SMPS and APS monitors, and PM{sub 2.5} light scattering extinction coefficient as measured by nephelometer. During the course of the project, measurement intercomparison data were developed for these instruments and several complementary measurements at the site. The report details the instrument set and operating procedures and describes the resulting data. Report subsections present an overview summary of the data, followed by detailed description of the systematic time behavior of PM{sub 2.5} and other specific particulate size fractions. Specific subsections are included for particle size distribution, light scattering, and particle sulfate data. The final subsection addresses application of the measurements to the practical questions of fine PM generation and transport, source attribution, and PM{sub 2.5} management strategies.

Ashley Williamson

2003-05-31

458

Particulate-Phase Carbonyls: Laboratory and Pacific 2001 Field Measurements  

NASA Astrophysics Data System (ADS)

Atmospheric aldehydes and ketones are important constituents of the gas phase. They are emitted from athropogenic and biogenic sources directly, but are also formed as secondary oxidation products of a variety of saturated and unsaturated hydrocarbons. Although their gas phase occurrence and chemistry is well known, the presence of these compounds in the particulate phase is not completely understood. A method has been developed to measure particulate phase carbonyls. Analysis was performed by a simultaneous extraction and derivatization of carbonyls by 2,4-dinitrophenylhydrazine. The subsequent derivatives are pre-concentrated and injected onto an HPLC and detected by UV absorption. Laboratory studies of the extraction kinetics, suggest that partitioning of even highly volatile carbonyls may be possible. Also, experiments performed to determine the extent of positive artifacts on Teflon coated filters, indicate that measurements of these volatile carbonyls are likely not a result of gas-phase adsorption to the filter. These studies also indicate that sampling on quartz fiber filters may introduce significantly more uncertainty with respect to positive artifacts. The analytical method was used to analyze filters sampled during the Pacific 2001 field campaign. Particulate samples were collected on Teflon coated glass-fiber filters. Samples were collected at an urban site (Slocan Park,Vancouver), a rural site (Langley) and an elevated rural mountain site (Eagle Ridge, Sumas). Preliminary results show several carbonyls present in aerosols, at pg/m3 to ng/m3 levels. Detected carbonyls of possible anthropogenic origin include formaldehyde, acetaldehyde, acetone, propanal, glyoxal and methylglyoxal. Detected carbonyls of biogenic origin include pinonaldehyde and nopinone, known oxidation products of the biogenically emitted a-pinene and b-pinene. Possible mechanisms for carbonyl partitioning and implications for their contribution to aerosols in the Lower Fraser Valley will be presented.

Liggio, J.; McLaren, R.

2002-12-01

459

40 CFR 52.1476 - Control strategy: Particulate matter.  

Code of Federal Regulations, 2013 CFR

...false Control strategy: Particulate matter. 52.1476 Section 52.1476 Protection...1476 Control strategy: Particulate matter. (a) The requirements of subpart...the national standards for particulate matter in the Northwest Nevada and Nevada...

2013-07-01

460

40 CFR 52.275 - Particulate matter control.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Particulate matter control. 52.275 Section 52.275... California § 52.275 Particulate matter control. (a) The following rules...because they control emissions of particulate matter, and because there is no...

2013-07-01

461

40 CFR 52.2059 - Control strategy: Particulate matter.  

Code of Federal Regulations, 2013 CFR

...false Control strategy: Particulate matter. 52.2059 Section 52.2059 Protection...2059 Control strategy: Particulate matter. (a) Pennsylvania has committed...Controlling Nontraditional Particulate Matter Emissions Task Completion date...

2013-07-01

462

40 CFR 52.1476 - Control strategy: Particulate matter.  

Code of Federal Regulations, 2010 CFR

...Control Strategy Analysis for Particulates, from the Nevada Control...the emission limitation on particulate matter. (1) Clark County District Board of Health, Table 27.1, (Particulate Matter from Process...

2009-07-01

463

40 CFR 52.1476 - Control strategy: Particulate matter.  

Code of Federal Regulations, 2010 CFR

...Control Strategy Analysis for Particulates, from the Nevada Control...the emission limitation on particulate matter. (1) Clark County District Board of Health, Table 27.1, (Particulate Matter from Process...

2010-07-01

464

40 CFR 52.2584 - Control strategy; Particulate matter.  

Code of Federal Regulations, 2013 CFR

...Control strategy; Particulate matter. (a) Part DâDisapproval...standards for particulate matter, because it does not contain...and March 30, 1990, the State of Wisconsin submitted committal SIPs for particulate matter with an aerodynamic...

2013-07-01

465

MP2 and CCSD(T) study on hydrogen bonding, aromatic stacking and nonaromatic stacking  

Microsoft Academic Search

Three groups of molecular clusters were studied using the coupled cluster method with non-iterative triple excitations (CCSD(T)) and the second-order Møller-Plesset perturbational method (MP2): H-bonded DNA base pairs ((cytosine)2, (isocytosine)2 and (uracil)2), aromatic stacked complexes ((pyrrol)2, (pyrimidine)2, (triazine)2, (aminotriazine)2, (4-aminopyrimidine)2 and (1-aminopyrimidine)2) and cyclic H-bonded and stacked (formamide)2 and (formamidine)2 dimers. The higher-order correlation energy contributions are repulsive in all

J. Šponer; P. Hobza

1997-01-01

466

Investigation of the relationship between particulate-bound mercury and properties of fly ash in a full-scale 100 MWe pulverized coal combustion boiler  

SciTech Connect

The properties of fly ash in coal-fired boilers influence the emission of mercury from power plants into the environment. In this study, seven different bituminous coals were burned in a full-scale 100 MWe pulverized coal combustion boiler and the derived fly ash samples were collected from a mechanical hopper (MH) and an electrostatic precipitator hopper (ESP). The mercury content, specific surface area (SSA), unburned carbon, and elemental composition of the fly ash samples were analyzed to evaluate the correlation between the concentration of particulate-bound mercury and the properties of coal and fly ash. For a given coal, it was found that the mercury content in the fly ash collected from the ESP was greater than in the fly ash samples collected from the MHP. This phenomenon may be due to a lower temperature of flue gas at the ESP (about 135{sup o}C) compared to the temperature at the air preheater (about 350{sup o}C). Also, a significantly lower SSA observed in MH ash might also contribute to the observation. A comparison of the fly ash samples generated from seven different coals using statistical methods indicates that the mercury adsorbed on ESP fly ashes has a highly positive correlation with the unburned carbon content, manganese content, and SSA of the fly ash. Sulfur content in coal showed a significant negative correlation with the Hg adsorption. Manganese in fly ash is believed to participate in oxidizing volatile elemental mercury (Hg{sup 0}) to ionic mercury (Hg{sup 2+}). The oxidized mercury in flue gas can form a complex with the fly ash and then get removed before the flue gas leaves the stack of the boiler.

Sen Li; Chin-Min Cheng; Bobby Chen; Yan Cao; Jacob Vervynckt; Amanda Adebambo; Wei-Ping Pan [Western Kentucky University, Bowling Green, KY (United States). Institute for Combustion Science and Environmental Technology

2007-12-15

467

Adsorption of nucleobase pairs on hexagonal boron nitride sheet: hydrogen bonding versus stacking.  

PubMed

The adsorption of hydrogen-bonded and stacked nucleobase pairs on the hexagonal boron nitride (h-BN) surface was studied by density functional theory and molecular dynamics methods. Eight types of nucleobase pairs (i.e., GG, AA, TT, CC, UU, AT, GC, and AU) were chosen as the adsorbates. The adsorption configurations, interaction energies, and electronic properties of the nucleobase pair on the h-BN surface were obtained and compared. The density of states analysis result shows that both the hydrogen-bonded and stacked nucleobase pairs were physisorbed on h-BN with minimal charge transfer. The hydrogen-bonded base pairs lying on the h-BN surface are significantly more stable than the stacked forms in both the gas and water phase. The molecular dynamics simulation result indicates that h-BN possessed high sensitivity for the nucleobases and the h-BN surface adsorption could revert the base pair interaction from stacking back to hydrogen bonding in aqueous environment. The h-BN surface could immobilize the nucleobases on its surface, which suggests the use of h-BN has good potential in DNA/RNA detection biosensors and self-assembly nanodevices. PMID:23689542

Ding, Ning; Chen, Xiangfeng; Wu, Chi-Man Lawrence; Li, Hui

2013-05-21

468

METAL TRANSPORT AND PARTICULATE MATTER (PM)  

EPA Science Inventory

This research will assist in identifying mechanisms of toxocity for particulate matter (PM) constituents. The hypothesis to be tested is that disequilibrium in metal transport in the lung follows exposure to particulate matter. This results in an oxidative stress, cell signaling...

469

Triboelectric technology for particulate emission measurement  

SciTech Connect

The author discusses how triboelectric technology (monitoring of particulate emission by sensing impacting particle charge transfer) has enabled a new generation of particulate emission detectors to be developed. They are providing to be much more suitable than traditional opacity methods. The reason for this is that they require little or no maintenance.

Averdieck, W.J. (Auburn International, Inc., Danvers, MA (USA))

1987-01-01

470

Planck blackbody emissive power in particulate media  

Microsoft Academic Search

Modifications of the Planck blackbody intensity and emissive power are proposed due to the modifications of the photon energy transport velocity and the density of states in particulate media. These modifications result from the multiple scattering of photons. These modifications affect the heat flux and temperature predictions in particulate media. Results show that current methods of predicting heat flux and

Ravi Prasher

2005-01-01

471

Machining of particulate metal matrix composites  

Microsoft Academic Search

Particulate metal matrix composites (PMMCs) are being widely used in the aerospace and automotive industry due to their favourable properties, mainly high specific strength and wear resistance. However, machining of particulate metal matrix composites presents a great challenge to the industry as the reinforcing particles easily abrade most of the common cutting tool materials. Polycrystalline diamond (PCD) tools appear to

Mariam S El-Gallab

1999-01-01

472

Latex allergen in respirable particulate air pollution  

Microsoft Academic Search

Objective: Urban air samples contain numerous irregular respirable black particles, which may be airborne tire fragments. A major component of tires is natural latex. Proteins of natural latex can act as adjuvants and as antigens capable of eliciting immediate hypersensitivity, making their presence in particulate air pollution an important clinical issue. Methods: Particulate air pollutants were collected by volumetric sampling

P. Brock Williams; Martin P. Buhr; Richard W. Weber; Micheal A. Volz; Jerald W. Koepke; John C. Selner

1995-01-01

473

Airborne Particulates in New York City  

Microsoft Academic Search

This study was undertaken to identify seasonal and source effects on the par-ticulate contaminants of the New York City atmosphere and ultimately to relate the concentrations of these contaminants to the tissue concentrations in residents of New York City. Continual weekly samples of particulates have been collected at three stations in the New York area on 8 by 10 in.

Theo. J. Kneip; Merril Eisenbud; Clifford D. Strehlow; Peter C. Freudenthal

1970-01-01

474

Cometary particulate analyzer design definition study  

Microsoft Academic Search

A concept for remotely determining the relative abundance of elements contained in cometary particulates collected by a spacecraft was conducted with very encouraging results. The technique utilizes a short high intensity burst of laser radiation to vaporize and ionize collected particulate material. Ions extracted from this laser-produced plasma are analyzed in a time of flight mass spectrometer to yield an

N. G. Utterback

1981-01-01

475

Understanding the Particulate Nature of Matter.  

ERIC Educational Resources Information Center

|Cites studies related to students' misconceptions about the particulate nature of matter. Stresses that a good understanding of these concepts is fundamental to the study of chemistry itself. Reports on a study of preservice elementary teachers views of the particulate nature of matter before instruction on the topic. (TW)|

Gabel, Dorothy L.; And Others

1987-01-01

476

MONITORING AIRBORNE PARTICULATE MASS BY BETA ABSORPTION  

EPA Science Inventory

A prototype airborne particulate mass monitor, using the principle of beta radiation absorption, has been fabricated and evaluated on airborne particulate matter. A detection sensitivity of 80 microgram/sq cm was attained. A series of samples were collected, and a comparison was ...

477

ENGINEERED PARTICULATES FOR CO-FIRING OF DIVERSE FEEDSTOCKS  

SciTech Connect

The goal of this project is to develop a novel methodology for the formation of engineered particulates of energy-relevant material. Specifically, we aim to control interparticle cohesion in such a way as to generate macro-particles or agglomerates of several differing types of primary particles in specific proportions such that they would be of utility for co-firing applications. In Phase I of this project, we used a combination of experimentation and simulation to validate theoretically derived mixing/segregation rules for cohesive granular materials in static systems, flowing systems, and gas-solid systems.

Joseph J. McCarthy; Kunal Jain; Hongming Li; Deliang Shi

2004-03-01

478

Cooling of stacks of plates shielded by porous screens  

NASA Astrophysics Data System (ADS)

This paper addresses the question of how to cool a stack of parallel, heat-generating boards when the flow is impeded by electromagnetic screens placed upstream and downstream of the stack. Four separate designs are considered: (1) forced convection cooling of a stack with board-to-board spacing selected to minimize the stack-coolant thermal resistance; (2) forced convection cooling of stack with fixed board-to-board spacing; (3) natural convection cooling of a vertical stack with spacing selected to minimize the overall thermal resistance; and (4) natural convection cooling of a vertical stack with fixed spacing. The optimal spacings in designs (1) and (3) are determined by intersecting the known asymptotic solutions for stacks with small spacings and stacks with large spacings. The results of parts (1) and (2) are extended to applications where the stack is cooled by immersion in a free stream. We show that the effect of the screen is controlled by a single dimensionless group, which is identified for each class of designs, namely, forced versus natural convection, and high- versus low-screen Reynolds number. Engineering results are reported for the design of screens made of wire meshes, or perforated plate with square (sharp) edges.

Bejan, A.; Kim, S. J.; Morega, Al. M.; Lee, S. W.

1995-02-01

479

Mobile Particulate Emission Studies of New York City Vehicles  

NASA Astrophysics Data System (ADS)

Emissions from both diesel and gasoline powered motor vehicles are a significant source of urban particulate (PM2.5) and trace gas pollution. Emission characteriza- tions of motor vehicles are typically performed using a dynamometer. Few studies have been performed which characterize emissions from in-use vehicles using a mo- bile sampling platform. This work, which was part of the PM2.5 Technology Assess- ment and Characterization Study in New York (PMTACS-NY), describes the applica- tion of new instrumentation for rapid (1-5 second) and real-time characterization of particulate emissions from in-use vehicles . An Aerosol Mass Spectrometer (AMS) was deployed on the Aerodyne Research (ARI) mobile laboratory designed to "chase" target vehicles in and around the New York City area and measure their emissions under actual driving conditions. The AMS provides quantitative particle size and composition information for volatile and semi- volatile matter (0.05-2.5 um). The AMS was operated in a fast acquisition mode de- signed to monitor particle emissions from the mobile sources. In this mode mass spec- tra (0-300 amu) and chemically speciated particle size distributions were recorded at 4 sec intervals. In addition to the AMS, the Mobile Laboratory was equipped with the ARI tunable diode laser (TILDAS) system which was configured to measure NO, NO2, CO, CH4, SO2 and formaldehyde, a global positioning system, a condensation particle counter, and a Licor CO2 instrument. The simultaneous measurement of particulate mass loading and plume CO2 enabled the calculation of emission indices for the targeted vehicles. Particulate matter emis- sion indices for a representative fraction of the NYC Metropolitan Transit Authority (MTA) bus fleet were determined in an effort to characterize new emission control technologies currently implemented by the NYC MTA. In addition to total particle emission indices, chemically speciated sulfate and organic mass loadings and size distributions were determined. Representative mass spectral signatures and size dis- tributions observed from the exhaust plume particles and correlations between the simultaneous gas and particulate measurements will be discussed. Differences in ob- served particle emission factors and compositions between buses using different fuels and technologies will also be presented.

Canagaratna, M.; Jayne, J.; Shi, Q.; Kolb, C. E.; Worsnop, D.

480

ADVANCED FLUE GAS CONDITIONING AS A RETROFIT UPGRADE TO ENHANCE PM COLLECTION FROM COAL-FIRED ELECTRIC UTILITY BOILERS  

SciTech Connect

The U.S. Department of Energy and ADA Environmental Solutions are engaged in a project to develop commercial flue gas conditioning additives. The objective is to develop conditioning agents that can help improve particulate control performance of smaller or under-sized electrostatic precipitators on utility coal-fired boilers. The new chemicals will be used to control both the electrical resistivity and the adhesion or cohesivity of the fly ash. There is a need to provide cost-effective and safer alternatives to traditional flue gas conditioning with SO{sub 3} and ammonia. During this reporting quarter, two cohesivity-specific additive formulations, ADA-44C and ADA-51, were evaluated in a full-scale trial at the American Electric Power Conesville plant. Ammonia conditioning was also evaluated for comparison. ADA-51 and ammonia conditioning significantly reduced rapping and non-rapped particulate re-entrainment based on stack opacity monitor data. Based on the successful tests to date, ADA-51 will be evaluated in a long-term test.

Kenneth E. Baldrey

2003-02-01