Science.gov

Sample records for stack sampling location

  1. Scaled tests and modeling of effluent stack sampling location mixing.

    PubMed

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

    2009-02-01

    A three-dimensional computational fluid dynamics computer model was used to evaluate the mixing at a sampling system 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 Standards Institute standard, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stacks and Ducts of Nuclear Facilities. This standard requires that the sampling location be well-mixed and stipulates specific tests to verify the extent of mixing. The exhaust system for the Radiochemical Processing Laboratory was modeled with a computational fluid dynamics code to better understand the flow and contaminant mixing and to predict mixing test results. The modeled 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 computational fluid dynamics code provides reasonable predictions for velocity, cyclonic flow, gas, and aerosol uniformity, although the code predicts greater improvement in mixing as the injection point is moved farther away from the sampling location than is actually observed by measurements. In expanding from small to full scale, the modeled predictions for full-scale measurements show similar uniformity values as in the scale model. This work indicated that a computational fluid dynamics code can be a cost-effective aid in designing or retrofitting a facility's stack sampling location that will be required to meet standard ANSI/HPS N13.1-1999.

  2. Assessment of the 296-S-21 Stack Sampling Probe Location

    SciTech Connect

    Glissmeyer, John A.

    2006-09-08

    Tests were performed to assess the suitability of the location of the air sampling probe on the 296-S-21 stack according to the criteria of ANSI N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stacks and Ducts of Nuclear Facilities. Pacific Northwest National Laboratory conducted most tests on a 3.67:1 scale model of the stack. CH2MHill also performed some limited confirmatory tests on the actual stack. The tests assessed the capability of the air-monitoring probe to extract a sample representative of the effluent stream. The tests were conducted for the practical combinations of operating fans and addressed: (1) Angular Flow--The purpose is to determine whether the velocity vector is aligned with the sampling nozzle. The average yaw angle relative to the nozzle axis should not be more than 20. The measured values ranged from 5 to 11 degrees on the scale model and 10 to 12 degrees on the actual stack. (2) Uniform Air Velocity--The gas momentum across the stack cross section where the sample is extracted should be well mixed or uniform. The uniformity is expressed as the variability of the measurements about the mean, the coefficient of variance (COV). The lower the COV value, the more uniform the velocity. The acceptance criterion is that the COV of the air velocity must be ?20% across the center two-thirds of the area of the stack. At the location simulating the sampling probe, the measured values ranged form 4 to 11%, which are within the criterion. To confirm the validity of the scale model results, air velocity uniformity measurements were made both on the actual stack and on the scale model at the test ports 1.5 stack diameters upstream of the sampling probe. The results ranged from 6 to 8% COV on the actual stack and 10 to 13% COV on the scale model. The average difference for the eight runs was 4.8% COV, which is within the validation criterion. The fact that the scale model results were slightly higher than the

  3. Review of the Physical Science Facility Stack Air Sampling Probe Locations

    SciTech Connect

    Glissmeyer, John A.

    2007-09-30

    This letter report reviews compliance of the current design of the Physical Science Facility (PSF) stack air sampling locations with the ANSI/HPS N13.1-1999 standard. The review was based on performance criteria used for locating air sampling probes, the design documents provided and available information on systems previously tested for compliance with the criteria. Recommendations are presented for ways to bring the design into compliance with the requirements for the sampling probe placement.

  4. Assessment of the HV-C2 Stack Sampling Probe Location

    SciTech Connect

    Glissmeyer, John A.; Droppo, James G.

    2007-08-24

    Tests were performed to evaluate the location of the air-sampling probe in the proposed design for the Waste Treatment Plant’s HV-C2 air exhaust stack. The evaluation criteria come from ANSI/HPS N13.1-1999, “Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stacks and Ducts of Nuclear Facilities.” Pacific Northwest National Laboratory conducted the tests on a 3.67:1 scale model of the stack. Limited confirmatory tests on the actual stack will need to be conducted during cold startup of the High Level Waste Treatment Facility. The tests documented here assessed the capability of the air-monitoring probe to extract a sample representative of the effluent stream in accordance with criteria in ANSI/HPS N13.1. The test parameters covered the expected range of system flowrates with both one and two operating fans. The current stack design calls for the sampling probe to be located about 10 diameters downstream of the junction of the duct from Fan A with the stack. In accordance with the statement of work and the test plan, the test measurements were made at that location and also at one point upstream and another downstream. An adjustment was made for the distance between a typical sampling probe inlet and the centerline of its mounting flange. Thus, the test measurements were made at three positions designated as Test Port 1, 2, and 3, respectively. The designed HV-C2 exhaust system includes dampers on the fan discharges. Custom-scale model dampers were fabricated to simulate the same number and configuration of damper blades shown in the design documents received from BNI. A subset of the test runs was run without the dampers to determine whether the dampers should be included in future tests on scale models.

  5. Assessment of the 3430 Building Filtered Exhaust Stack Sampling Probe Location

    SciTech Connect

    Glissmeyer, John A.; Flaherty, Julia E.

    2010-07-16

    Pacific Northwest National Laboratory performed a demonstration to determine the acceptable location in which to place an air sampling probe for emissions monitoring for radionuclides in the exhaust air discharge from the new 3430 Building Filtered Exhaust Stack. The method was to adopt the results of a previously performed test series for a system of similar configuration, followed by a partial test on the actual system to verify the applicability of previously performed tests. The qualification criteria included 1) a uniform air velocity, 2) an average flow angle that does not deviate from the axis of the duct by more than 20°, 3) a uniform concentration of tracer gases, and 4) a uniform concentration of tracer particles. Section 1 provides background information for the demonstration, and Section 2 describes the test strategy, including the criteria for the applicability of model results and the test matrix. Section 3 describes the flow -angle test and the velocity uniformity test, Section 4 provides the test results, and Section 5 provides the conclusions. Appendix A includes the test data sheets, and Appendix B gives applicable qualification results from the previously tested model stack. The data from the previously tested and similarly designed stack was demonstrated to be applicable to the current design for the 3430 Building Filtered Exhaust Stack. The 3430 stack was tested in both January and May of 2010 to document the results of several changes that were made to the exhaust system after the January tests. The 3430 stack meets the qualification criteria given in the American National Standards Institute/Health Physics Society N13.1 standard. Changes to the system configuration or operations outside of the bounds of this report (e.g., exhaust velocity increases, relocation of sample probe) will require retesting/reevaluation to determine compliancewith the requirements.

  6. Assessment of the Revised 3410 Building Filtered Exhaust Stack Sampling Probe Location

    SciTech Connect

    Yu, Xiao-Ying; Recknagle, Kurtis P.; Glissmeyer, John A.

    2013-12-01

    In order to support the air emissions permit for the 3410 Building, Pacific Northwest National Laboratory performed a series of tests in the exhaust air discharge from the reconfigured 3410 Building Filtered Exhaust Stack. The objective was to determine whether the location of the air sampling probe for emissions monitoring meets the applicable regulatory criteria governing such effluent monitoring systems. In particular, the capability of the air sampling probe location to meet the acceptance criteria of ANSI/HPS N13.1-2011 , Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities was determined. The qualification criteria for these types of stacks address 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 of tracer particle concentration. Testing was performed to conform to the quality requirements of NQA-1-2000. Fan configurations tested included all fan combinations of any two fans at a time. Most of the tests were conducted at the normal flow rate, while a small subset of tests was performed at a slightly higher flow rate achieved with the laboratory hood sashes fully open. The qualification criteria for an air monitoring probe location are taken from ANSI/HPS N13.1-2011 and are paraphrased as follows with key results summarized: 1. Angular Flow—The average air velocity angle must not deviate from the axis of the stack or duct by more than 20°. Our test results show that the mean angular flow angles at the center two-thirds of the ducts are smaller than 4.5% for all testing conditions. 2. Uniform Air Velocity—The acceptance criterion is that the COV of the air velocity must be ≤ 20% across the center two thirds of the area of the stack. Our results show that the COVs of the air velocity across the center two-thirds of the stack are smaller than 2.9% for all testing conditions. 3

  7. Assessment of the Building 3430 Filtered Exhaust Stack Sampling Probe Location

    SciTech Connect

    Glissmeyer, John A.

    2010-04-13

    Pacific Northwest National Laboratory performed a demonstration to determine the acceptable location in which to place an air sampling probe for emissions monitoring for radionuclides in the exhaust air discharge from the new 3430 Building Filtered Pathway Stack . The method was to adopt the results of a previously performed test series for a system of similar configuration, followed by a partial test on the actual system to verify the applicability of previously performed tests. The qualification criteria included 1) a uniform air velocity, 2) an average flow angle that does not deviate from the axis of the duct by more than 20°, 3) a uniform concentration of tracer gases, and 4) a uniform concentration of tracer particles. Section 1 provides background information for the demonstration, and Section 2 describes the test strategy, including the criteria for the applicability of model results and the test matrix. Section 3 describes the flow angle test and the velocity uniformity test, Section 4 provides the test results, and Section 5 provides the conclusions. Appendix A includes the test data sheets, and Appendix B gives applicable qualification results from the previously tested model stack. The data from the previously tested and similarly designed stack was demonstrated to be applicable to the current design for the 3430 Building Filtered Pathway stack. Therefore, this new system also meets the qualification criteria given in the ANSI/HPS N13.1 standard. Changes to the system configuration or operations outside of the bounds of this report (e.g., exhaust velocity increases, relocation of sample probe) will require retesting/reevaluation to determine compliance to the requirements.

  8. Assessment of the 3420 Building Filtered Exhaust Stack Sampling Probe Location

    SciTech Connect

    Glissmeyer, John A.; Flaherty, Julia E.

    2010-07-16

    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.

  9. Assessment of the 3410 Building Filtered Exhaust Stack Sampling Probe Location

    SciTech Connect

    Glissmeyer, John A.; Flaherty, Julia E.

    2010-07-16

    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.

  10. Assessment of the LV-C2 Stack Sampling Probe Location for Compliance with ANSI/HPS N13.1-1999

    SciTech Connect

    Glissmeyer, John A.; Antonio, Ernest J.; Flaherty, Julia E.

    2015-09-01

    This document reports on a series of tests conducted to assess the proposed air sampling location for the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Low-Activity Waste (LAW) C2V (LV-C2) exhaust stack with respect to the applicable criteria regarding the placement of an air sampling probe. Federal regulations require that a sampling probe be located in the exhaust stack according to the criteria established by the American National Standards Institute/Health Physics Society (ANSI/HPS) N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities. These criteria address the capability of the sampling probe to extract a sample that represents the effluent stream. The tests were conducted on the LV-C2 scale model system. Based on the scale model tests, the location proposed for the air sampling probe in the scale model stack meets the requirements of the ANSI/HPS N13.1-1999 standard for velocity uniformity, flow angle, gas tracer and particle tracer uniformity. Additional velocity uniformity and flow angle tests on the actual stack will be necessary during cold startup to confirm the validity of the scale model results in representing the actual stack.

  11. Assessment of Waste Treatment Plant Lab C3V (LB-S1) Stack Sampling Probe Location for Compliance with ANSI/HPS N13.1-1999

    SciTech Connect

    Glissmeyer, John A.; Geeting, John GH

    2013-02-01

    This report documents a series of tests used to assess the proposed air sampling location in the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Lab C3V (LB-S1) exhaust stack with respect to the applicable criteria regarding the placement of an air sampling probe. Federal regulations require that an air sampling probe be located in the exhaust stack in accordance with the criteria of American National Standards Institute/Health Physics Society (ANSI/HPS) N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities. These criteria address the capability of the sampling probe to extract a sample that represents the effluent stream.

  12. Assessment of the National Research Universal Reactor Proposed New Stack Sampling Probe Location for Compliance with ANSI/HPS N13.1-1999

    SciTech Connect

    Glissmeyer, John A.; Antonio, Ernest J.; Flaherty, Julia E.

    2016-02-29

    This document reports on a series of tests conducted to assess the proposed air sampling location for the National Research Universal reactor (NRU) complex exhaust stack, located in Chalk River, Ontario, Canada, with respect to the applicable criteria regarding the placement of an air sampling probe. Due to the age of the equipment in the existing monitoring system, and the increasing difficulty in acquiring replacement parts to maintain this equipment, a more up-to-date system is planned to replace the current effluent monitoring system, and a new monitoring location has been proposed. The new sampling probe should be located within the exhaust stack according to the criteria established by the American National Standards Institute/Health Physics Society (ANSI/HPS) N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities. These criteria address the capability of the sampling probe to extract a sample that represents the effluent stream. The internal Pacific Northwest National Laboratory (PNNL) project for this task was 65167, Atomic Energy Canada Ltd. Chalk River Effluent Duct Flow Qualification. The testing described in this document was guided by the Test Plan: Testing of the NRU Stack Air Sampling Position (TP-STMON-032).

  13. Assessment of the LV-S2 & LV-S3 Stack Sampling Probe Locations for Compliance with ANSI/HPS N13.1-1999

    SciTech Connect

    Glissmeyer, John A.; Antonio, Ernest J.; Flaherty, Julia E.; Amidan, Brett G.

    2014-09-30

    This document reports on a series of tests conducted to assess the proposed air sampling locations for the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Group 1-2A exhaust stacks with respect to the applicable criteria regarding the placement of an air sampling probe. The LV-C2, LV-S2, and LV-S3 exhaust stacks were tested together as a group (Test Group 1-2A). This report only covers the results of LV-S2 and LV-S3; LV-C2 will be reported on separately. Federal regulations1 require that a sampling probe be located in the exhaust stack according to the criteria established by the American National Standards Institute/Health Physics Society (ANSI/HPS) N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities. 2 These criteria address the capability of the sampling probe to extract a sample that represents the effluent stream.

  14. Stack sampling apparatus

    DOEpatents

    Lind, Randall F; Lloyd, Peter D; Love, Lonnie J; Noakes, Mark W; Pin, Francois G; Richardson, Bradley S; Rowe, John C

    2014-09-16

    An apparatus for obtaining samples from a structure includes a support member, at least one stabilizing member, and at least one moveable member. The stabilizing member has a first portion coupled to the support member and a second portion configured to engage with the structure to restrict relative movement between the support member and the structure. The stabilizing member is radially expandable from a first configuration where the second portion does not engage with a surface of the structure to a second configuration where the second portion engages with the surface of the structure.

  15. Assessment of the Group 5-6 (LB C2, LB S2, LV S1) Stack Sampling Probe Locations for Compliance with ANSI/HPS N13.1 1999

    SciTech Connect

    Glissmeyer, John A.; Flaherty, Julia E.; Piepel, Gregory F.

    2011-03-11

    This document reports on a series of tests to assess the proposed air sampling locations for the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Group 5-6 exhaust stacks with respect to the applicable criteria regarding the placement of an air sampling probe. The LB-C2, LV-S1, and LB S2 exhaust stacks were tested together as a group (Test Group 5-6) because the common factor in their design is that the last significant flow disturbance upstream of the air sampling probe is a reduction in duct diameter. Federal regulations( ) require that a sampling probe be located in the exhaust stack according to the criteria of the American National Standards Institute/Health Physics Society (ANSI/HPS) N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities. These criteria address the capability of the sampling probe to extract a sample that represents the effluent stream. The testing on scale models of the stacks conducted for this project was part of the River Protection Project—Waste Treatment Plant Support Program under Contract No. DE-AC05-76RL01830 according to the statement of work issued by Bechtel National Inc. (BNI, 24590-QL-SRA-W000-00101, N13.1-1999 Stack Monitor Scale Model Testing and Qualification, Revision 1, 9/12/2007) and Work Authorization 09 of Memorandum of Agreement 24590-QL-HC9-WA49-00001. The internal Pacific Northwest National Laboratory (PNNL) project for this task is 53024, Work for Hanford Contractors Stack Monitoring. The testing described in this document was further guided by the Test Plan Scale Model Testing the Waste Treatment Plant LB-C2, LB-S2, and LV-S1 (Test Group 5-6) Stack Air Sampling Positions (TP-RPP-WTP-594). The tests conducted by PNNL during 2009 and 2010 on the Group 5-6 scale model systems are described in this report. The series of tests consists of various measurements taken over a grid of points in the duct cross-section at the designed sampling

  16. Locating tremor using stacked products of correlations

    NASA Astrophysics Data System (ADS)

    Li, Ka Lok; Sadeghisorkhani, Hamzeh; Sgattoni, Giulia; Gudmundsson, Olafur; Roberts, Roland

    2017-04-01

    We introduce a back-projection method to locate tremor sources using products of cross-correlation envelopes of time series between seismic stations. For a given subset of n stations, we calculate the (n - 1)th-order product of cross-correlation envelopes and we stack the back-projected products over combinations of station subsets. We show that compared to existing correlation methods and for realistic signal and noise characteristics, this way of combining information can significantly reduce the effects of correlated (spurious or irrelevant signals) and uncorrelated noise. Each back-projected product constitutes an individual localized estimate of the source locations, as opposed to a hyperbola for the existing correlation techniques, assuming a uniform velocity in two dimensions. We demonstrate the method with synthetic examples and a real-data example from tremor at Katla Volcano, Iceland, in July 2011. Despite very complex near-surface structure, including strong topography and thick ice cover, the method appears to produce robust estimates of tremor location.

  17. Assessment of the Group 3-4 (HV-S1, HV-S2, IHLW-S1) Stack Sampling Probe Locations for Compliance with ANSI/HPS N13.1-1999

    SciTech Connect

    Glissmeyer, John A.; Flaherty, Julia E.; Antonio, Ernest J.

    2013-01-01

    This document reports on a series of tests conducted to assess the proposed air sampling locations for the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Group 3-4 exhaust stacks with respect to the applicable criteria regarding the placement of an air sampling probe. The HV-S1, HV-S2, and IHLW-S1 exhaust stacks were tested together as a group (Test Group 3-4) because they share a geometric attribute: the common factor in their design is that the last significant flow disturbance upstream of the air sampling probe is a jog (i.e., two conjoined bends of equal and opposite curvature resulting in a change in elevation of the duct). Federal regulations require that a sampling probe be located in the exhaust stack according to criteria established by the American National Standards Institute/Health Physics Society (ANSI/HPS) N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities. These criteria address the capability of the sampling probe to extract a sample that represents the effluent stream.

  18. 40 CFR 61.33 - Stack sampling.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium § 61.33 Stack... Administrator. (d) All samples shall be analyzed and beryllium emissions shall be determined within 30 days...

  19. 40 CFR 61.33 - Stack sampling.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium § 61.33 Stack... Administrator. (d) All samples shall be analyzed and beryllium emissions shall be determined within 30 days...

  20. 40 CFR 61.33 - Stack sampling.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium § 61.33 Stack... Administrator. (d) All samples shall be analyzed and beryllium emissions shall be determined within 30 days...

  1. 40 CFR 61.33 - Stack sampling.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium § 61.33 Stack... Administrator. (d) All samples shall be analyzed and beryllium emissions shall be determined within 30 days...

  2. 40 CFR 61.33 - Stack sampling.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium § 61.33 Stack... results reported to the Administrator. (d) All samples shall be analyzed and beryllium emissions shall be...

  3. Contemporary sample stacking in analytical electrophoresis.

    PubMed

    Šlampová, Andrea; Malá, Zdena; Pantůčková, Pavla; Gebauer, Petr; Boček, Petr

    2013-01-01

    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).

  4. Contemporary sample stacking in analytical electrophoresis.

    PubMed

    Malá, Zdena; Šlampová, Andrea; Křivánková, Ludmila; Gebauer, Petr; Boček, Petr

    2015-01-01

    This contribution is a methodological review of the publications about the topic from the last 2 years. Therefore, it is primarily organized according to the methods and procedures used in surveyed papers and the origin and type of sample and specification of analytes form the secondary structure. The introductory part about navigation in the architecture of stacking brings a brief characterization of the various stacking methods, with the description of mutual links to each other and important differences among them. The main body of the article brings a survey of publications organized according to main principles of stacking and then according to the origin and type of the sample. Provided that the paper cited gave explicitly the relevant data, information about the BGE(s) used, procedure, detector employed, and reached LOD and/or concentration effect is given. The papers where the procedure used is a combination of diverse fragments and parts of various stacking techniques are mentioned in a special section on combined techniques. The concluding remarks in the final part of the review evaluate present state of art and the trends of sample stacking in CE.

  5. Microseismic event location by master-event waveform stacking

    NASA Astrophysics Data System (ADS)

    Grigoli, F.; Cesca, S.; Dahm, T.

    2016-12-01

    Waveform stacking location methods are nowadays extensively used to monitor induced seismicity monitoring assoiciated with several underground industrial activities such as Mining, Oil&Gas production and Geothermal energy exploitation. In the last decade a significant effort has been spent to develop or improve methodologies able to perform automated seismological analysis for weak events at a local scale. This effort was accompanied by the improvement of monitoring systems, resulting in an increasing number of large microseismicity catalogs. The analysis of microseismicity is challenging, because of the large number of recorded events often characterized by a low signal-to-noise ratio. A significant limitation of the traditional location approaches is that automated picking is often done on each seismogram individually, making little or no use of the coherency information between stations. In order to improve the performance of the traditional location methods, in the last year, alternative approaches have been proposed. These methods exploits the coherence of the waveforms recorded at different stations and do not require any automated picking procedure. The main advantage of this methods relies on their robustness even when the recorded waveforms are very noisy. On the other hand, like any other location method, the location performance strongly depends on the accuracy of the available velocity model. When dealing with inaccurate velocity models, in fact, location results can be affected by large errors. Here we will introduce a new automated waveform stacking location method which is less dependent on the knowledge of the velocity model and presents several benefits, which improve the location accuracy: 1) it accounts for phase delays due to local site effects, e.g. surface topography or variable sediment thickness 2) theoretical velocity model are only used to estimate travel times within the source volume, and not along the whole source-sensor path. We

  6. Automated microseismic event location using Master-Event Waveform Stacking

    PubMed Central

    Grigoli, Francesco; Cesca, Simone; Krieger, Lars; Kriegerowski, Marius; Gammaldi, Sergio; Horalek, Josef; Priolo, Enrico; Dahm, Torsten

    2016-01-01

    Accurate and automated locations of microseismic events are desirable for many seismological and industrial applications. The analysis of microseismicity is particularly challenging because of weak seismic signals with low signal-to-noise ratio. Traditional location approaches rely on automated picking, based on individual seismograms, and make no use of the coherency information between signals at different stations. This strong limitation has been overcome by full-waveform location methods, which exploit the coherency of waveforms at different stations and improve the location robustness even in presence of noise. However, the performance of these methods strongly depend on the accuracy of the adopted velocity model, which is often quite rough; inaccurate models result in large location errors. We present an improved waveform stacking location method based on source-specific station corrections. Our method inherits the advantages of full-waveform location methods while strongly mitigating the dependency on the accuracy of the velocity model. With this approach the influence of an inaccurate velocity model on the results is restricted to the estimation of travel times solely within the seismogenic volume, but not for the entire source-receiver path. We finally successfully applied our new method to a realistic synthetic dataset as well as real data. PMID:27185465

  7. Automated microseismic event location using Master-Event Waveform Stacking

    NASA Astrophysics Data System (ADS)

    Grigoli, Francesco; Cesca, Simone; Krieger, Lars; Kriegerowski, Marius; Gammaldi, Sergio; Horalek, Josef; Priolo, Enrico; Dahm, Torsten

    2016-05-01

    Accurate and automated locations of microseismic events are desirable for many seismological and industrial applications. The analysis of microseismicity is particularly challenging because of weak seismic signals with low signal-to-noise ratio. Traditional location approaches rely on automated picking, based on individual seismograms, and make no use of the coherency information between signals at different stations. This strong limitation has been overcome by full-waveform location methods, which exploit the coherency of waveforms at different stations and improve the location robustness even in presence of noise. However, the performance of these methods strongly depend on the accuracy of the adopted velocity model, which is often quite rough; inaccurate models result in large location errors. We present an improved waveform stacking location method based on source-specific station corrections. Our method inherits the advantages of full-waveform location methods while strongly mitigating the dependency on the accuracy of the velocity model. With this approach the influence of an inaccurate velocity model on the results is restricted to the estimation of travel times solely within the seismogenic volume, but not for the entire source-receiver path. We finally successfully applied our new method to a realistic synthetic dataset as well as real data.

  8. Cold Vacuum Drying Facility Stack Air Sampling System Qualification Tests

    SciTech Connect

    Glissmeyer, John A.

    2001-01-24

    This report documents tests that were conducted to verify that the air monitoring system for the Cold Vacuum Drying Facility ventilation exhaust stack meets the applicable regulatory criteria regarding the placement of the air sampling probe, sample transport, and stack flow measurement accuracy.

  9. Sampled-time control of a microbial fuel cell stack

    NASA Astrophysics Data System (ADS)

    Boghani, Hitesh C.; Dinsdale, Richard M.; Guwy, Alan J.; Premier, Giuliano C.

    2017-07-01

    Research into microbial fuel cells (MFCs) has reached the point where cubic metre-scale systems and stacks are being built and tested. Apart from performance enhancement through catalysis, materials and design, an important research area for industrial applicability is stack control, which can enhance MFCs stack power output. An MFC stack is controlled using a sampled-time digital control strategy, which has the advantage of intermittent operation with consequent power saving, and when used in a hybrid series stack connectivity, can avoid voltage reversals. A MFC stack comprising four tubular MFCs was operated hydraulically in series. Each MFC was connected to an independent controller and the stack was connected electrically in series, creating a hybrid-series connectivity. The voltage of each MFC in the stack was controlled such that the overall series stack voltage generated was the algebraic sum (1.26 V) of the individual MFC voltages (0.32, 0.32, 0.32 and 0.3). The controllers were able to control the individual voltages to the point where 2.52 mA was drawn from the stack at a load of 499.9 Ω (delivering 3.18 mW). The controllers were able to reject the disturbances and perturbations caused by electrical loading, temperature and substrate concentration.

  10. Principles for Sampling Airborne Radioactivity from Stacks

    SciTech Connect

    Glissmeyer, John A.

    2010-10-18

    This book chapter describes the special processes involved in sampling the airborne effluents from nuclear faciities. The title of the book is Radioactive Air Sampling Methods. The abstract for this chapter was cleared as PNNL-SA-45941.

  11. Synchronized sampling improves fault location

    SciTech Connect

    Kezunovic, M.; Perunicic, B.

    1995-04-01

    Transmission line faults must be located accurately to allow maintenance crews to arrive at the scene and repair the faulted section as soon as possible. Rugged terrain and geographical layout cause some sections of power transmission lines to be difficult to reach. In the past, a variety of fault location algorithms were introduced as either an add-on feature in protective relays or stand-alone implementation in fault locators. In both cases, the measurements of current and voltages were taken at one terminal of a transmission line only. Under such conditions, it may become difficult to determine the fault location accurately, since data from other transmission line ends are required for more precise computations. In the absence of data from the other end, existing algorithms have accuracy problems under several circumstances, such as varying switching and loading conditions, fault infeed from the other end, and random value of fault resistance. Most of the one-end algorithms were based on estimation of voltage and current phasors. The need to estimate phasors introduces additional difficulty in high-speed tripping situations where the algorithms may not be fast enough in determining fault location accurately before the current signals disappear due to the relay operation and breaker opening. This article introduces a unique concept of high-speed fault location that can be implemented either as a simple add-on to the digital fault recorders (DFRs) or as a stand-alone new relaying function. This advanced concept is based on the use of voltage and current samples that are synchronously taken at both ends of a transmission line. This sampling technique can be made readily available in some new DFR designs incorporating receivers for accurate sampling clock synchronization using the satellite Global Positioning System (GPS).

  12. 40 CFR 61.44 - Stack sampling.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium Rocket Motor... within 30 days after samples are taken and before any subsequent rocket motor firing or propellant...

  13. 40 CFR 61.44 - Stack sampling.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium Rocket Motor... within 30 days after samples are taken and before any subsequent rocket motor firing or propellant...

  14. 40 CFR 61.44 - Stack sampling.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium Rocket Motor... within 30 days after samples are taken and before any subsequent rocket motor firing or propellant...

  15. 40 CFR 61.44 - Stack sampling.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium Rocket Motor... within 30 days after samples are taken and before any subsequent rocket motor firing or propellant...

  16. 40 CFR 61.44 - Stack sampling.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium Rocket Motor... within 30 days after samples are taken and before any subsequent rocket motor firing or propellant...

  17. Qualification Tests for the New Air Sampling System at the 296-Z-1 Stack

    SciTech Connect

    Glissmeyer, John A.; Maughan, A D.; Jarvis, Timothy T.

    2002-09-19

    This report documents tests performed by Pacific Northwest National Laboratory to verify that the new air monitoring system for the 296-Z-1 ventilation exhaust stack meets the applicable regulatory criteria regarding the placement of the air sampling probe, sample transport, and stack flow measurement accuracy. These criteria ensure that the contaminants in the stack are well mixed with the airflow at the location of the probe so that the collected sample represents the whole. The sequence of tests addresses the acceptability of the flow angle relative to the probe uniformity of air velocity and gaseous and particle tracers in the cross section of the stack delivery of the sample from the sampler nozzle to the collection filter. The tests conducted on the air monitoring system demonstrated that the location for the air-sampling probe meets all performance criteria for air sampling systems at nuclear facilities. The performance criterion for particle transport was also met. All tests were successful, and all acceptance criteria were met.

  18. Experimental performance evaluation of two stack sampling systems in a plutonium facility

    SciTech Connect

    Glissmeyer, J.A.

    1992-04-01

    The evaluation of two routine stack sampling systems at the Z-Plant plutonium facility operated by Rockwell International for USERDA is part of a larger study, sponsored by Rockwell and conducted by Battelle, Pacific Northwest Laboratories, of gaseous effluent sampling systems. The gaseous effluent sampling systems evaluated are located at the main plant ventilation stack (291-Z-1) and at a vessel vent stack (296-Z-3). A preliminary report, which was a paper study issued in April 1976, identified many deficiencies in the existing sampling systems and made recommendations for corrective action. The objectives of this experimental evaluation of those sampling systems were as follows: Characterize the radioactive aerosols in the stack effluents; Develop a tracer aerosol technique for validating particulate effluent sampling system performance; Evaluate the performance of the existing routine sampling systems and their compliance with the sponsor`s criteria; and Recommend corrective action where required. The tracer aerosol approach to sampler evaluation was chosen because the low concentrations of radioactive particulates in the effluents would otherwise require much longer sampling times and thus more time to complete this evaluation. The following report describes the sampling systems that are the subject of this study and then details the experiments performed. The results are then presented and discussed. Much of the raw and finished data are included in the appendices.

  19. Single point aerosol sampling: Evaluation of mixing and probe performance in a nuclear stack

    SciTech Connect

    Rodgers, J.C.; Fairchild, C.I.; Wood, G.O.

    1995-02-01

    Alternative Reference Methodologies (ARMs) have been developed for sampling of radionuclides from stacks and ducts that differ from the methods required by the U.S. EPA. The EPA methods are prescriptive in selection of sampling locations and in design of sampling probes whereas the alternative methods are performance driven. Tests were conducted in a stack at Los Alamos National Laboratory to demonstrate the efficacy of the ARMs. Coefficients of variation of the velocity tracer gas, and aerosol particle profiles were determined at three sampling locations. Results showed numerical criteria placed upon the coefficients of variation by the ARMs were met at sampling stations located 9 and 14 stack diameters from flow entrance, but not at a location that is 1.5 diameters downstream from the inlet. Experiments were conducted to characterize the transmission of 10 {mu}m aerodynamic equivalent diameter liquid aerosol particles through three types of sampling probes. The transmission ratio (ratio of aerosol concentration at the probe exit plane to the concentration in the free stream) was 107% for a 113 L/min (4-cfm) anisokinetic shrouded probe, but only 20% for an isokinetic probe that follows the EPA requirements. A specially designed isokinetic probe showed a transmission ratio of 63%. The shrouded probe performance would conform to the ARM criteria; however, the isokinetic probes would not.

  20. VOCs Speciation From Steam Boiler Stacks of Industries Located in Naucalpan

    NASA Astrophysics Data System (ADS)

    Mejia, G. M.; Tejeda, D. D.; Bremauntz, M. P.; Valdez, A.; Montufar, P. C.; Martinez, M. A.; Sierra, M. J.; Gonzalez, C. A.

    2007-05-01

    Results of VOCs speciation from industrial steam boiler stacks located in Naucalpan are presented and discussed. This municipality is located north of the Metropolitan Zone of the Valley of Mexico (MZVM). Speciation of VOCs is important to generate information about sources of pollution, to update emission inventories, to study the dynamics of pollutants in the atmosphere, and to estimate possible risks of population exposure. This information is valuable for decision making on air pollution control strategies. Samples from 35 steam boilers form industries burning Diesel, LPG, or CNG were taken using the US-EPA Method 18. Selected samples from the use of different fuels were analyzed using gas chromatography and flame ionization detection (GC-FID) according to US-EPA protocol TO-14. The VOCs analyzed included alkanes of 9 carbons or less, alkenes of 7 carbons or less and aromatics (families of benzene). The results show consistency on the VOCs detected on Diesel samples. The main compounds found were 1- Butene+iButylene, m/p-Xylene, Ethane, Propene, Propane, Acetylene, 2Me-1Butene, and Toluene. The average concentrations of these compounds were in the range of 130 to 385 ppbC. The results of LPG samples did not show a definite pattern of VOCs, although light components predominate and, in some samples, Toluene and Xylene. These last components were not expected for industries reporting the use of LPG, perhaps due to the use of a combination of fuels and mistakes in the reports of fuel used at the time of sampling. The analysis of CNG samples show predominance of light VOCs, in the range of 90 to 300 ppbC. As in the case of LPG, some aromatics showed high concentrations in some samples analyzed perhaps due to the use of different fuels in the boiler. The results of this study are the first results of VOCs speciation obtained form exhaust gases from stacks of Mexican industries. The data reported are valuable to analyze emission inventories of VOCs and to better

  1. 40 CFR 141.703 - Sampling locations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Monitoring Requirements § 141.703 Sampling locations. (a) Systems required to conduct source water monitoring... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Sampling locations. 141.703 Section... a sampling tap is available where the sources are combined prior to treatment, systems must collect...

  2. The influence of piezoceramic stack location on nonlinear behavior of Langevin transducers.

    PubMed

    Mathieson, Andrew; Cardoni, Andrea; Cerisola, Niccolò; Lucas, Margaret

    2013-06-01

    Power ultrasonic applications such as cutting, welding, and sonochemistry often use Langevin transducers to generate power ultrasound. Traditionally, it has been proposed that the piezoceramic stack of a Langevin transducer should be located in the nodal plane of the longitudinal mode of vibration, ensuring that the piezoceramic elements are positioned under a uniform stress during transducer operation, maximizing element efficiency and minimizing piezoceramic aging. However, this general design rule is often partially broken during the design phase if features such as a support flange or multiple piezoceramic stacks are incorporated into the transducer architecture. Meanwhile, it has also been well documented in the literature that power ultrasonic devices driven at high excitation levels exhibit nonlinear behaviors similar to those observed in Duffing-type systems, such as resonant frequency shifts, the jump phenomenon, and hysteretic regions. This study investigates three Langevin transducers with different piezoceramic stack locations by characterizing their linear and nonlinear vibrational responses to understand how the stack location influences nonlinear behavior.

  3. The role of sample height in the stacking diagram of colloidal mixtures under gravity

    NASA Astrophysics Data System (ADS)

    Geigenfeind, Thomas; de las Heras, Daniel

    2017-02-01

    Bulk phase separation is responsible for the occurrence of stacks of different layers in sedimentation of colloidal mixtures. A recently proposed theory (de las Heras and Schmidt 2013 Soft Matter 9 8636) establishes a unique connection between the bulk phase behaviour and sedimentation-diffusion-equilibrium. The theory constructs a stacking diagram of all possible sequences of stacks under gravity in the limit of very high (infinite) sample heights. Here, we study the stacking diagrams of colloidal mixtures at finite sample height, h. We demonstrate that h plays a vital role in sedimentation-diffusion-equilibrium of colloidal mixtures. The region of the stacking diagram occupied by a given sequence of stacks depends on h. Hence, two samples with different heights but identical colloidal concentrations can develop different stacking sequences. In addition, the stacking diagrams for different heights can be qualitatively different since some stacking sequences occur only in a given interval of sample heights. We use the theory to investigate the stacking diagrams of both model bulk systems and mixtures of patchy particles that differ either by the number or by the types of patches.

  4. The role of sample height in the stacking diagram of colloidal mixtures under gravity.

    PubMed

    Geigenfeind, Thomas; de Las Heras, Daniel

    2017-02-15

    Bulk phase separation is responsible for the occurrence of stacks of different layers in sedimentation of colloidal mixtures. A recently proposed theory (de las Heras and Schmidt 2013 Soft Matter 9 8636) establishes a unique connection between the bulk phase behaviour and sedimentation-diffusion-equilibrium. The theory constructs a stacking diagram of all possible sequences of stacks under gravity in the limit of very high (infinite) sample heights. Here, we study the stacking diagrams of colloidal mixtures at finite sample height, h. We demonstrate that h plays a vital role in sedimentation-diffusion-equilibrium of colloidal mixtures. The region of the stacking diagram occupied by a given sequence of stacks depends on h. Hence, two samples with different heights but identical colloidal concentrations can develop different stacking sequences. In addition, the stacking diagrams for different heights can be qualitatively different since some stacking sequences occur only in a given interval of sample heights. We use the theory to investigate the stacking diagrams of both model bulk systems and mixtures of patchy particles that differ either by the number or by the types of patches.

  5. Modeling and Qualification of a Modified Emission Unit for Radioactive Air Emissions Stack Sampling Compliance.

    PubMed

    Barnett, J Matthew; Yu, Xiao-Ying; Recknagle, Kurtis P; Glissmeyer, John A

    2016-11-01

    A planned laboratory space and exhaust system modification to the Pacific Northwest National Laboratory Material Science and Technology Building indicated that a new evaluation of the mixing at the air sampling system location would be required for compliance to ANSI/HPS N13.1-2011. The modified exhaust system would add a third fan, thereby increasing the overall exhaust rate out the stack, thus voiding the previous mixing study. Prior to modifying the radioactive air emissions exhaust system, a three-dimensional computational fluid dynamics computer model was used to evaluate the mixing at the sampling system location. Modeling of the original three-fan system indicated that not all mixing criteria could be met. A second modeling effort was conducted with the addition of an air blender downstream of the confluence of the three fans, which then showed satisfactory mixing results. The final installation included an air blender, and the exhaust system underwent full-scale tests to verify velocity, cyclonic flow, gas, and particulate uniformity. The modeling results and those of the full-scale tests show agreement between each of the evaluated criteria. The use of a computational fluid dynamics code was an effective aid in the design process and allowed the sampling system to remain in its original location while still meeting the requirements for sampling at a well mixed location.

  6. Modeling and Qualification of a Modified Emission Unit for Radioactive Air Emissions Stack Sampling Compliance

    SciTech Connect

    Barnett, J. Matthew; Yu, Xiao-Ying; Recknagle, Kurtis P.; Glissmeyer, John A.

    2016-01-01

    A planned laboratory space and exhaust system modification to the Pacific Northwest National Laboratory Material Science and Technology Building indicated a new evaluation of the mixing at the air sampling system location would be required for compliance to ANSI/HPS N13.1-2011. The modified exhaust system would add a third fan thereby increasing the overall exhaust rate out the stack thus voiding the previous mixing study. Prior to modifying the radioactive air emissions exhaust system, a three-dimensional computational fluid dynamics computer model was used to evaluate the mixing at the sampling system location. Modeling of the new original three-fan system indicated that not all mixing criteria could be met. A second modeling effort was conducted with the addition of an air blender downstream of the confluence of the three fans which then showed satisfactory mixing results. The final installation included an air blender, and the exhaust system underwent full-scale tests to verify velocity, cyclonic flow, gas, and particulate uniformity. The modeling results and those of the full-scale tests show agreement between each of the evaluated criteria. The use of a computational fluid dynamics code was an effective aid in the design process and allowed the sampling system to remain in its original location while still meeting the requirements for sampling at a well-mixed location.

  7. Sample stacking for the analysis of catechins by microemulsion EKC.

    PubMed

    Huang, Hsi-Ya; Huang, I-Yun; Liang, Hsin-hui; Lee, Szetsen

    2007-06-01

    In this study, an on-line concentration method, ASEI (anion-selective exhaustive injection)-sweeping technology which was coupled with microemulsion EKC (MEEKC), was used to analyze and detect six catechins ((-)-epicatechin, (+)-catechin, (-)-epigallocatechin gallate, (-)-epicatechin gallate, (-)-epigallocatechin, and (-)-gallocatechin). In addition to the effects of the buffer pH and electrolyte concentration on stacking, the compositions of microemulsion (types of oil phase, and types and levels of cosurfactant) also dominated the stacking effect of catechins. In MEEKC, the effect of the type of oil in microemulsion on separation mechanism is often unclear. This study had demonstrated that the oil type in microemulsion indeed altered the affinity of oil droplets with analytes. Finally, this proposed ASEI-sweeping MEEKC method was able to detect trace level of catechins in food products that was not previously possible by a normal MEEKC method.

  8. Sampling of power plant stacks for air toxic emissions: Final report for Phases 1 and 2

    SciTech Connect

    1995-04-28

    A test program to collect and analyze size-fractionated stack gas particulate samples for selected inorganic hazardous air pollutants (HAPs) was conducted . 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 characterization, 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. Field testing was conducted in two phases. The Phase I field program was performed over the period of August 24 through September 20, 1992, at the Tennessee Valley Authority Widows Creek Unit 8 Power Station, located near Stevenson (Jackson County), Alabama, on the Tennessee River. Sampling activities for Phase II were conducted from September 11 through October 14, 1993. Widows Creek Unit 8 is a 575-megawatt plant that uses bituminous coal averaging 3.7% sulfur and 13% ash. Downstream of the boiler, a venture wet scrubbing system is used for control of both sulfur dioxide and particulate emissions. There is no electrostatic precipitator (ESP) in this system. This system is atypical and represents only about 5% of the US utility industry. However, this site was chosen for this study because of the lack of information available for this particulate emission control system.

  9. An automated local and regional seismic event location method based on waveform stacking

    NASA Astrophysics Data System (ADS)

    Grigoli, F.; Cesca, S.; Dahm, T.

    2013-12-01

    Seismic event location using automated procedures is a very important task in microseismic monitoring as well as within early warning applications. Increasingly large datasets recorded by dense network has recently favoured the development of different automated location methods. These methods are requested to be noise robust, since microseismic records are often characterized by a low signal-to-noise ratios. Most of the aforementioned standard automated location routines rely on automated phase picking and seismic phases identification (generally only P and S) and are generally based on the minimization of the residuals between the theoretical and observed arrival times of the main seismic phases. While different developed approaches allow to accurately pick P onsets, the automatic picking of the S onsets is still challenging, and posing a significant limit to the location performance. We present here a picking free location method based on the use of different characteristic functions, able to identify P and S phases. Both characteristic functions are based on the Short-Term-Average/Long-Term-Average (STA/LTA) traces. For P phases, we use as characteristic function the STA/LTA trace of the vertical energy function, whereas for the S phases we use the STA/LTA traces of a function obtained using the Principal Component Analysis (PCA) technique. In order to locate a seismic event, the space of possible locations is scanned and both P and S characteristic functions are stacked along travel time surfaces corresponding to the selected hypocenter. Iterating this procedure on a three-dimensional grid we retrieve a multidimensional matrix whose absolute maximum corresponds tot he coordinates of the seismic event. We show the performance of our method with different applications, at different scales: 1) s set of low magnitude events recorded by a local network in southern Italy and 2) a set of seismic events recorded by a regional seismic network in Turkey. This work has

  10. Recovery and Determination of Adsorbed Technetium on Savannah River Site Charcoal Stack Samples

    SciTech Connect

    Lahoda, Kristy G.; Engelmann, Mark D.; Farmer, Orville T.; Ballou, Nathan E.

    2008-03-01

    Experimental results are provided for the sample analyses for technetium (Tc) in charcoal samples placed in-line with a Savannah River Site (SRS) processing stack effluent stream as a part of an environmental surveillance program. The method for Tc removal from charcoal was based on that originally developed with high purity charcoal. Presented is the process that allowed for the quantitative analysis of 99Tc in SRS charcoal stack samples with and without 97Tc as a tracer. The results obtained with the method using the 97Tc tracer quantitatively confirm the results obtained with no tracer added. All samples contain 99Tc at the pg g-1 level.

  11. Testing the sampling efficiency of a nuclear power station stack monitor

    SciTech Connect

    Stroem, L.H.

    1997-08-01

    The test method comprises the injection of known amounts of monodisperse particles in the stack air stream, at a suitable point upstream of the sampling installation. To find a suitable injection polls, the gas flow was mapped by means of a tracer gas, released in various points in the stack base. The resulting concentration distributions at the stack sampler level were observed by means of an array of gas detectors. An injection point that produced symmetrical distribution over the stack area, and low concentrations at the stack walls was selected for the particle tests. Monodisperse particles of 6, 10, and 19 {mu}m aerodynamic diameter, tagged with dysprosium, were dispersed in the selected injection point. Particle concentration at the sampler level was measured. The losses to the stack walls were found to be less than 10 %. The particle concentrations at the four sampler inlets were calculated from the observed gas distribution. The amount calculated to be aspirated into the sampler piping was compared with the quantity collected by the sampling train ordinary filter, to obtain the sampling line transmission efficiency. 1 ref., 2 figs.

  12. Acupuncture injection for field amplified sample stacking and glass microchip-based capillary gel electrophoresis.

    PubMed

    Ha, Ji Won; Hahn, Jong Hoon

    2017-02-01

    Acupuncture sample injection is a simple method to deliver well-defined nanoliter-scale sample plugs in PDMS microfluidic channels. This acupuncture injection method in microchip CE has several advantages, including minimization of sample consumption, the capability of serial injections of different sample solutions into the same microchannel, and the capability of injecting sample plugs into any desired position of a microchannel. Herein, we demonstrate that the simple and cost-effective acupuncture sample injection method can be used for PDMS microchip-based field amplified sample stacking in the most simplified straight channel by applying a single potential. We achieved the increase in electropherogram signals for the case of sample stacking. Furthermore, we present that microchip CGE of ΦX174 DNA-HaeⅢ digest can be performed with the acupuncture injection method on a glass microchip while minimizing sample loss and voltage control hardware.

  13. 40 CFR 141.703 - Sampling locations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... samples prior to the point of filter backwash water addition. (d) Bank filtration. (1) Systems that... applicable, must collect source water samples in the surface water prior to bank filtration. (2) Systems that use bank filtration as pretreatment to a filtration plant must collect source water samples from...

  14. 40 CFR 141.703 - Sampling locations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... samples prior to the point of filter backwash water addition. (d) Bank filtration. (1) Systems that... applicable, must collect source water samples in the surface water prior to bank filtration. (2) Systems that use bank filtration as pretreatment to a filtration plant must collect source water samples from...

  15. 40 CFR 141.703 - Sampling locations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... samples prior to the point of filter backwash water addition. (d) Bank filtration. (1) Systems that... applicable, must collect source water samples in the surface water prior to bank filtration. (2) Systems that use bank filtration as pretreatment to a filtration plant must collect source water samples from...

  16. 40 CFR 141.703 - Sampling locations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... samples prior to the point of filter backwash water addition. (d) Bank filtration. (1) Systems that... applicable, must collect source water samples in the surface water prior to bank filtration. (2) Systems that use bank filtration as pretreatment to a filtration plant must collect source water samples from...

  17. Visual offline sample stacking via moving neutralization boundary electrophoresis for analysis of heavy metal ion.

    PubMed

    Fan, Yinping; Li, Shan; Fan, Liuyin; Cao, Chengxi

    2012-06-15

    In this paper, a moving neutralization boundary (MNB) electrophoresis is developed as a novel model of visual offline sample stacking for the trace analysis of heavy metal ions (HMIs). In the stacking system, the cathodic-direction motion MNB is designed with 1.95-2.8mM HCl+98 mM KCl in phase alfa and 4.0mM NaOH+96 mM KCl in phase beta. If a little of HMI is present in phase alfa, the metal ion electrically migrates towards the MNB and react with hydroxyl ion, producing precipitation and moving precipitation boundary (MPB). The alkaline precipitation is neutralized by hydrogen ion, leading to a moving eluting boundary (MEB), release of HMI from its precipitation, circle of HMI from the MEB to the MPB, and highly efficient visual stacking. As a proof of concept, a set of metal ions (Cu(II), Co(II), Mn(II), Pb(II) and Cr(III)) were chosen as the model HMIs and capillary electrophoresis (CE) was selected as an analytical tool for the experiments demonstrating the feasibility of MNB-based stacking. As shown in this paper, (i) the visual stacking model was manifested by the experiments; (ii) there was a controllable stacking of HMI in the MNB system; (iii) the offline stacking could achieve higher than 123 fold preconcentration; and (iv) the five HMIs were simultaneously stacked via the developed stacking technique for the trace analyses with the limits of detection (LOD): 3.67×10(-3) (Cu(II)), 1.67×10(-3) (Co(II), 4.17×10(-3) (Mn(II)), 4.6×10(-4) (Pb(II)) and 8.40×10(-4)mM (Cr(III)). Even the off-line stacking was demonstrated for the use of CE-based HMI analysis, it has potential applications in atomic absorption spectroscopy (AAS), inductively coupled plasma-mass spectrometry (ICP-MS) and ion chromatography (IC) etc. Copyright © 2012 Elsevier B.V. All rights reserved.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  19. ROE Long Island Hypoxia Sample Locations

    EPA Pesticide Factsheets

    This point map shows concentrations of dissolved oxygen in bottom waters of Long Island Sound during the summer of 2014. Each point represents a site that was sampled by boat. Data were provided by EPA??s Long Island Sound Office and the Connecticut Department of Environmental Protection.

  20. ROE Gulf of Mexico Hypoxia Sample Locations

    EPA Pesticide Factsheets

    This dataset describes dissolved oxygen levels in the Gulf of Mexico. Individual sampling sites are represented by point data. The background polygon shows areas where the dissolved oxygen concentration is less than 2.0 milligrams per liter. The data were collected during the summer of 2014 by the Louisiana Universities Marine Consortium (LUMCON).

  1. Estimation of Location Difference for Fragmentary Samples.

    DTIC Science & Technology

    1980-12-01

    received a great deal of attention in recent statistical literature (Wilks, 1932; Anderson, 1957; Hocking and Smith, 1968; Meita and Gurland, 1969...to use the fragmentary sample in the most efficient way to estimate the shift parameter a. Gupta and Rohatgi (1981) considered the case that X and Y...from the incomplete pairs is a Hodges-Lehmann estimator of 6 based on Wilcoxon signed rank statistic . The estimator e(1,0) which uses all the data

  2. Biomass bale stack and field outlet locations assessment for efficient infield logistics

    USDA-ARS?s Scientific Manuscript database

    Harvested hay or biomass are traditionally baled for better handling and they are transported to the outlet for final utilization. For better management of bale logistics, producers often aggregate bales into stacks so that bale-hauling equipment can haul multiple bales for improved efficiency. Obje...

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

    SciTech Connect

    1995-02-21

    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.

  4. System effects in sample self-stacking CZE: single analyte peak splitting of salt-containing samples.

    PubMed

    Malá, Zdena; Gebauer, Petr; Bocek, Petr

    2009-03-01

    In CZE one often gets more peaks than the number of sample components. In practice the additional peaks are often left unexplained or assigned to unidentified impurities or system peaks although cases exist when one analyte forms two or more regular distinct zones. One source of such effects are samples with high salt content that are generally assumed to bring higher sensitivity due to the sample self-stacking mechanism. The subject of this contribution is the theoretical and experimental investigation of the electromigration behavior of salt-containing samples. It is shown that they can exhibit splitting of the analyte zone into mutually independent parts detectable as well-developed distinct peaks. Theory based on velocity diagrams and computer simulations reveals that these effects originate in the transient phase of separation where electromigration dispersion profiles and sharp boundaries are formed and evolve. During this, the sample may induce parallel existence of several transient sharp boundaries (including system boundaries) that are simultaneously capable of stacking an analyte. Their electromigration is convergent and depending on whether they merge before the analyte destacks from them, permanent or transient double or multiple peaks are formed. Presented examples of anionic and cationic systems show good agreement with theory. The appearance of multiple peaks can be very variable, ranging from double or triple peaks to a major peak with a minor peak quite apart. Knowledge of the peak-splitting mechanism allows both to identify its presence in a given BGE and sample and to find effective remedy.

  5. On-line concentration sample stacking coupled with water-in-oil microemulsion electrokinetic chromatography.

    PubMed

    Huang, Hsi-Ya; Liu, Wan-Ling; Singco, Brenda; Hsieh, Shih-Huan; Shih, Yung-Han

    2011-10-21

    This study describes for the first time, the ability of a normal stacking mode (NSM) on-line concentration step coupled with water-in-oil (W/O) microemulsion electrokinetic chromatography (MEEKC), using six common penicillin antibiotics (oxacillin, penicillin V, penicillin G, nafcillin, ampicillin, and amoxicillin) as test analytes. Optimization of penicillin separation in the conventional W/O MEEKC system demonstrated that change in the type and concentration of the oil phase (1-butanol) and column temperature had a pronounced effect on the separation. With the subsequent development of the NSM coupled with W/O MEEKC, improved separation and detection sensitivities were observed when an organic solvent plug (1-propanol; 1.04 cm) was placed between the W/O microemulsion and the sample solutions. This could be attributed to the solution viscosity difference between the aqueous sample zone and the organic solvent plug causing the penicillin to be stacked in this 1-propanol plug. The optimal NSM W/O MEEKC provided about 12-fold increase in detection sensitivity compared with conventional sample injection (50 mbar, 3 s). Finally, this proposed method was successfully applied in the analyses of several food samples (porcine organs) spiked with penicillin. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. On-line Sample Preconcentration Using Field-amplified Stacking Injection in Microchip Capillary Electrophoresis

    PubMed Central

    Gong, Maojun; Wehmeyer, Kenneth R.; Limbach, Patrick A.; Arias, Francisco; Heineman, William R.

    2008-01-01

    Previous reports describing sample stacking on microchip capillary electrophoresis (μCE) have regarded the microchip channels as a closed system and treated the bulk flow as in traditional capillary electrophoresis. This work demonstrates that the flows arising from the cross region should be investigated as an open system. It is shown that the pressure-driven flows into or from the branch channels due to bulk velocity mismatch in the main channel should not be neglected but can be used for liquid transportation in the channels. Based on these concepts, a sample preconcentration scheme was developed in a commercially available glass, single-cross chip for μCE. Similar to field-amplified stacking injection in traditional CE, a low conductivity sample buffer plug was introduced into the separation channel immediately before the negatively charged analyte molecules were injected. The detection sensitivity was improved by 94-, 108- and 160-fold for fluorescein-5-isothiocyanate, fluorescein disodium and 5-carboxyfluorescein, respectively, relative to a traditional pinched injection. The calibration curves for fluorescein and 5-carboxyfluorescein demonstrated good linearity in the concentration range (1 to 60 nM) investigated with acceptable reproducibility of migration time and peak height and area ratios (4 to 5% RSD). This preconcentration scheme will be of particular significance to the practical use of μCE in the emerging miniaturized analytical instrumentation. PMID:16737230

  7. Field enhancement sample stacking for analysis of organic acids in traditional Chinese medicine by capillary electrophoresis.

    PubMed

    Zhu, Qianqian; Xu, Xueqin; Huang, Yuanyuan; Xu, Liangjun; Chen, Guonan

    2012-07-13

    A technique known as field enhancement sample stacking (FESS) and capillary electrophoresis (CE) separation has been developed to analyze and detect organic acids in the three traditional Chinese medicines (such as Portulaca oleracea L., Crataegus pinnatifida and Aloe vera L.). In FESS, a reverse electrode polarity-stacking mode (REPSM) was applied as on-line preconcentration strategy. Under the optimized condition, the baseline separation of eight organic acids (linolenic acid, lauric acid, p-coumaric acid, ascorbic acid, benzoic acid, caffeic acid, succinic acid and fumaric acid) could be achieved within 20 min. Validation parameters of this method (such as detection limits, linearity and precision) were also evaluated. The detection limits ranged from 0.4 to 60 ng/mL. The results indicated that the proposed method was effective for the separation of mixtures of organic acids. Satisfactory recoveries were also obtained in the analysis of these organic acids in the above traditional Chinese medicine samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Direct visualization of solute locations in laboratory ice samples

    NASA Astrophysics Data System (ADS)

    Hullar, Ted; Anastasio, Cort

    2016-09-01

    Many important chemical reactions occur in polar snow, where solutes may be present in several reservoirs, including at the air-ice interface and in liquid-like regions within the ice matrix. Some recent laboratory studies suggest chemical reaction rates may differ in these two reservoirs. While investigations have examined where solutes are found in natural snow and ice, few studies have examined either solute locations in laboratory samples or the possible factors controlling solute segregation. To address this, we used micro-computed tomography (microCT) to examine solute locations in ice samples prepared from either aqueous cesium chloride (CsCl) or rose bengal solutions that were frozen using several different methods. Samples frozen in a laboratory freezer had the largest liquid-like inclusions and air bubbles, while samples frozen in a custom freeze chamber had somewhat smaller air bubbles and inclusions; in contrast, samples frozen in liquid nitrogen showed much smaller concentrated inclusions and air bubbles, only slightly larger than the resolution limit of our images (˜ 2 µm). Freezing solutions in plastic vs. glass vials had significant impacts on the sample structure, perhaps because the poor heat conductivity of plastic vials changes how heat is removed from the sample as it cools. Similarly, the choice of solute had a significant impact on sample structure, with rose bengal solutions yielding smaller inclusions and air bubbles compared to CsCl solutions frozen using the same method. Additional experiments using higher-resolution imaging of an ice sample show that CsCl moves in a thermal gradient, supporting the idea that the solutes in ice are present in mobile liquid-like regions. Our work shows that the structure of laboratory ice samples, including the location of solutes, is sensitive to the freezing method, sample container, and solute characteristics, requiring careful experimental design and interpretation of results.

  9. Large volume sample stacking in capillary zone electrophoresis for the monitoring of the degradation products of metribuzin in environmental samples.

    PubMed

    Quesada-Molina, Carolina; García-Campaña, Ana M; Del Olmo-Iruela, Laura; Del Olmo, Monsalud

    2007-09-14

    A capillary zone electrophoresis (CZE) method with UV-vis detection has been developed for the simultaneous monitoring of the major degradation products of metribuzin, i.e. deaminometribuzin (DA), deaminodiketometribuzin (DADK) and diketometribuzin (DK). The dissociation acid constants have also been estimated by CE and no significant differences have been observed with the values obtained by applying other techniques. Optimum separation has been achieved in less than 9 min in 40 mM sodium tetraborate buffer, pH 9.5 by applying a voltage of 15kV at 25 degrees C and using p-aminobenzoic acid as internal standard. In order to increase sensitivity, large volume sample stacking (LVSS) with polarity switching has been applied as on-line pre-concentration methodology. Detection limits of 10, 10 and 20 ng/mL for DA, DADK and DK, respectively were obtained. The method has been applied to soil samples, after pressurized liquid extraction (PLE). Samples were extracted at high temperature (103 degrees C and 1500 psi) using methanol as extraction solvent and sodium sulphate as drying agent. This PLE procedure was followed by an off-line pre-concentration and sample clean-up procedure by solid-phase extraction (SPE) using a LiChrolut EN sorbent column. These last two procedures were also suitable for the direct treatment of groundwater samples before CE analysis. The combination of both off-line and on-line pre-concentration procedures provided a significant improvement in sensitivity. LVSS provided pre-concentration factors of 4, 36 and 28 for DK, DA and DADK, respectively and with SPE a pre-concentration of 500-fold for the case of water samples and of 2.5-fold in the case of soil samples was obtained. The method is suitable for the monitoring of these residues in environmental samples with high sensitivity, precision and satisfactory recoveries.

  10. [Analysis of phthalate esters in plastic-packaging bags on-line sample stacking-microemulsion electrokinetic chromatography].

    PubMed

    Xiao, Jia; Huang, Ying; Wang, Minyi; Chen, Guonan

    2012-09-01

    Two convenient, effective, and reproducible methods using microemulsion electrokinetic chromatography (MEEKC)-normal stacking mode (NSM) and reversed electrode polarity stacking mode (REPSM) were developed for the on-line sample stacking of phthalate esters (PAEs). REPSM coupled with MEEKC increased the sensitivity of 937.5 to 7,143 times for four PAEs compared to the conventional MEEKC. The separating conditions in the MEEKC method were studied, and many factors influencing the two sample stacking processes were investigated in detail. The optimum sample matrices for the two stacking methods were as follows: 30 mmol/L sodium cholate (SC) and 30.0 mmol/L borate (pH 8.5). Additionally, sample injections as large as 3.45 kPa x 40 s and 3.45 kPa x 90 s were applied for NSM-MEEKC and REPSM-MEEKC, respectively. The linear relationship and reproducibility were also examined. Under the optimum conditions, the detection limits (S/N = 3) of the PAEs were in the ranges of 0.021 - 0.33 mg/L and 0.7 - 4 microg/L for NSM-MEEKC and REPSM-MEEKC, respectively. The proposed REPSM-MEEKC has been successfully applied to determine PAEs in plastic-packaging bags, and the spiked recoveries were in the range of 89.1% - 105.6% with satisfactory results.

  11. 40 CFR 761.304 - Determining sample location.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Determining sample location. 761.304 Section 761.304 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT POLYCHLORINATED BIPHENYLS (PCBs) MANUFACTURING, PROCESSING, DISTRIBUTION IN COMMERCE, AND...

  12. Sample stacking with in-column silylation for less volatile polar compounds using GC-MS.

    PubMed

    Cho, Seungil

    2012-03-01

    This paper presents sample stacking with in-column silylation (SIS) for quantitative analysis of less volatile polar compounds using gas chromatography-mass spectrometry (GC-MS). This was achieved by the combination of sandwiched in-column silylation and multiple injections (up to 100 times or 100 μL in total). N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) was used as a silylating reagent. For the SIS technique, samples were introduced multiple N times (N = 2~100) into a capillary column in between BSTFA injections. The quantitative characteristic of SIS technique was studied using bisphenol A (BPA) as a model compound. The sandwiched in-column silylation for the less volatile polar compounds effectively replaced polar hydrogen with trimethylsilyl group to reduce sample adsorption and band broadening. Meanwhile, multiple injections at the SIS technique contributed to increase the sensitivity quantitatively. The capability and limitation of this analytical approach were further investigated with various types of compounds such as hydroxyls, carboxylic acids, and amine. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Field-amplified sample stacking-sweeping of vitamins B determination in capillary electrophoresis.

    PubMed

    Dziomba, Szymon; Kowalski, Piotr; Bączek, Tomasz

    2012-12-07

    A capillary electrophoretic method for determination of five water soluble vitamins B along with baclofen as an internal standard has been developed and assessed in context of precision, accuracy, sensitivity, freedom from interference, linearity, detection and quantification limits. On-line preconcentration technique, namely field-amplified sample stacking (FASS)-sweeping, has been employed in respect to obtain more sensitive analysis. Separation conditions received after optimization procedure were as following background electrolyte (BGE), 10 mM NaH(2)PO(4), 80 mM SDS, (pH 7.25); sample matrix (SM), 10 mM NaH(2)PO(4) (pH 4.60); uncoated fused silica capillary (50 μm i.d. × 67 cm length); UV spectrophotometric detection at 200 nm; injection times: 10s and 30s at 3.45 kPa; applied voltage 22 kV; temperature 22°C. Validation parameters, namely precision, accuracy and linearity, were considered as satisfactory. Under the optimized conditions, it has been also successfully applied for vitamins B determination in bacterial growth medium and commercially available Ilex paraguariensis leaves. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Fuel cell stack arrangements

    DOEpatents

    Kothmann, Richard E.; Somers, Edward V.

    1982-01-01

    Arrangements of stacks of fuel cells and ducts, for fuel cells operating with separate fuel, oxidant and coolant streams. An even number of stacks are arranged generally end-to-end in a loop. Ducts located at the juncture of consecutive stacks of the loop feed oxidant or fuel to or from the two consecutive stacks, each individual duct communicating with two stacks. A coolant fluid flows from outside the loop, into and through cooling channels of the stack, and is discharged into an enclosure duct formed within the loop by the stacks and seals at the junctures at the stacks.

  15. Optimizing Soil Moisture Sampling Locations for Validation Networks for SMAP

    NASA Astrophysics Data System (ADS)

    Roshani, E.; Berg, A. A.; Lindsay, J.

    2013-12-01

    Soil Moisture Active Passive satellite (SMAP) is scheduled for launch on Oct 2014. Global efforts are underway for establishment of soil moisture monitoring networks for both the pre- and post-launch validation and calibration of the SMAP products. In 2012 the SMAP Validation Experiment, SMAPVEX12, took place near Carman Manitoba, Canada where nearly 60 fields were sampled continuously over a 6 week period for soil moisture and several other parameters simultaneous to remotely sensed images of the sampling region. The locations of these sampling sites were mainly selected on the basis of accessibility, soil texture, and vegetation cover. Although these criteria are necessary to consider during sampling site selection, they do not guarantee optimal site placement to provide the most efficient representation of the studied area. In this analysis a method for optimization of sampling locations is presented which combines the state-of-art multi-objective optimization engine (non-dominated sorting genetic algorithm, NSGA-II), with the kriging interpolation technique to minimize the number of sampling sites while simultaneously minimizing the differences between the soil moisture map resulted from the kriging interpolation and soil moisture map from radar imaging. The algorithm is implemented in Whitebox Geospatial Analysis Tools, which is a multi-platform open-source GIS. The optimization framework is subject to the following three constraints:. A) sampling sites should be accessible to the crew on the ground, B) the number of sites located in a specific soil texture should be greater than or equal to a minimum value, and finally C) the number of sampling sites with a specific vegetation cover should be greater than or equal to a minimum constraint. The first constraint is implemented into the proposed model to keep the practicality of the approach. The second and third constraints are considered to guarantee that the collected samples from each soil texture categories

  16. Ultrasensitive detection of bacteria by microchip electrophoresis based on multiple-concentration approaches combining chitosan sweeping, field-amplified sample stacking, and reversed-field stacking.

    PubMed

    Wang, Zhi-Fang; Cheng, Shuang; Ge, Shu-Li; Wang, Huan; Wang, Qing-Jiang; He, Pin-Gang; Fang, Yu-Zhi

    2012-02-07

    In this paper we describe an on-chip multiple-concentration method combining chitosan (CS) sweeping, reversed-field stacking, and field-amplified sample stacking for highly efficient detection of bacteria. Escherichia coli was selected as a model bacterium to investigate the efficiency of this multiple-concentration method. CS was the most suitable sweeping agent for microchip electrophoresis, replacing the usually used cetyltrimethylammonium bromide for capillary electrophoresis. The additive taurine had a synergistic effect by enhancing the interaction between CS and the surface of the bacteria, thus improving the analysis sensitivity. All steps of the concentration method and related mechanisms are described and discussed in detail. A concentration enhancement factor of approximately 6000 was obtained using this concentration method under optimal conditions as compared to using no concentration step, and the detection limit of E. coli was 145 CFU/mL. The multiple-concentration methodology was also applied for the quantification of bacteria in surface water, and satisfactory results were achieved. The application of this methodology showed that the concentration enhancement of bacteria clearly conferred advantageous sensitivity, speed, and sample volume compared to established methods.

  17. A multi-dimensional sampling method for locating small scatterers

    NASA Astrophysics Data System (ADS)

    Song, Rencheng; Zhong, Yu; Chen, Xudong

    2012-11-01

    A multiple signal classification (MUSIC)-like multi-dimensional sampling method (MDSM) is introduced to locate small three-dimensional scatterers using electromagnetic waves. The indicator is built with the most stable part of signal subspace of the multi-static response matrix on a set of combinatorial sampling nodes inside the domain of interest. It has two main advantages compared to the conventional MUSIC methods. First, the MDSM is more robust against noise. Second, it can work with a single incidence even for multi-scatterers. Numerical simulations are presented to show the good performance of the proposed method.

  18. Design-based inference in time-location sampling.

    PubMed

    Leon, Lucie; Jauffret-Roustide, Marie; Le Strat, Yann

    2015-07-01

    Time-location sampling (TLS), also called time-space sampling or venue-based sampling is a sampling technique widely used in populations at high risk of infectious diseases. The principle is to reach individuals in places and at times where they gather. For example, men who have sex with men meet in gay venues at certain times of the day, and homeless people or drug users come together to take advantage of services provided to them (accommodation, care, meals). The statistical analysis of data coming from TLS surveys has been comprehensively discussed in the literature. Two issues of particular importance are the inclusion or not of sampling weights and how to deal with the frequency of venue attendance (FVA) of individuals during the course of the survey. The objective of this article is to present TLS in the context of sampling theory, to calculate sampling weights and to propose design-based inference taking into account the FVA. The properties of an estimator ignoring the FVA and of the design-based estimator are assessed and contrasted both through a simulation study and using real data from a recent cross-sectional survey conducted in France among drug users. We show that the estimators of prevalence or a total can be strongly biased if the FVA is ignored, while the design-based estimator taking FVA into account is unbiased even when declarative errors occur in the FVA.

  19. Hair analysis for abused drugs by capillary zone electrophoresis with field-amplified sample stacking.

    PubMed

    Tagliaro, F; Manetto, G; Crivellente, F; Scarcella, D; Marigo, M

    1998-04-05

    The present paper describes the methodological optimisation and validation of a capillary zone electrophoresis method for the determination of morphine, cocaine and 3,4-methylenedioxymethamphetamine (MDMA) in hair, with injection based on field-amplified sample stacking. Diode array UV absorption detection was used to improve analytical selectivity and identification power. Analytical conditions: running buffer 100 mM potassium phosphate adjusted to pH 2.5 with phosphoric acid, applied potential 10 kV, temperature 20 degrees C, injection by electromigration at 10 kV for 10 s, detection by UV absorption at the fixed wavelength of 200 nm or by recording the full spectrum between 190 and 400 nm. Injection conditions: the dried hair extracts were reconstituted with a low-conductivity solvent (0.1 mM formic acid), the injection end of the capillary was dipped in water for 5 s without applying pressure (external rinse step), then a plug of 0.1 mM phosphoric acid was loaded by applying 0.5 psi for 10 s and, finally, the sample was injected electrokinetically at 10 kV for 10 s. Under the described conditions, the limit of detection was 2 ng/ml for MDMA, 8 ng/ml for cocaine and 6 ng/ml for morphine (with a signal-to-noise ratio of 5). The lowest concentration suitable for recording interpretable spectra was about 10-20-times the limit of detection of each analyte. The intraday and day-to-day reproducibility of migration times (n = 6), with internal standardisation, was characterised by R.S.D. values < or = 0.6%; peak area R.S.D.s were better than 10% in intraday and than 15% in day-to-day experiments. Analytical linearity was good with R2 better than 0.9990 for all the analytes.

  20. Large-volume sample stacking-capillary electrophoresis used for the determination of 3-nitrotyrosine in rat urine.

    PubMed

    Maeso, Nuria; Cifuentes, Alejandro; Barbas, Coral

    2004-09-25

    Large-volume sample stacking using the electroosmotic flow (EOF) pump technique has been investigated for the quantification of 3-nitrotyrosine in urine of diabetic rats. The best separation conditions for these highly complex samples were obtained using capillary electrophoresis (CE) in the reversed polarity mode (i.e., injecting at the cathode and detecting at the anode) using cetyltrimethylammonium bromide (CTAB) in the running buffer. The optimum CE separation conditions were achieved using a phosphate buffer prepared with 0.15M phosphoric acid and 0.5 mM CTAB adjusted to pH 6.4 with sodium hydroxide. In such CE conditions, the limit of detection (LOD) was 1.77 microM for 3-nitrotyrosine with normal injection mode, meanwhile with the large-volume sample stacking technique a more than 20-fold improvement was observed (i.e., LOD = 0.08 microM was obtained) without noticeable loss of resolution. This value allowed the detection of 3-nitrotyrosine in urine from diabetic rats. To our knowledge, this work is one of the few applications showing the great possibilities of these stacking procedures to analyse biological samples by CE.

  1. Insights into cyclodextrin interactions during sample stacking using capillary isotachophoresis with on-line microcoil NMR detection.

    PubMed

    Almeida, Valentino K; Larive, Cynthia K

    2005-09-01

    On-line capillary isotachophoresis (cITP)-NMR experiments were used to probe the interactions of the pharmaceutical compounds S-alprenolol, S-atenolol, R-propranolol, R-salbutamol and S-terbutaline with beta-cyclodextrin (beta-CD) during cITP concentration. In cITP, ionic analytes are concentrated and separated on the basis of their electrophoretic mobility. Because neutral molecules have an electrophoretic mobility of zero, they are normally not concentrated or separated in electrophoretic experiments like cITP. Most of the analytes studied were concentrated by cITP sample stacking by a factor of around 300. For analytes that formed a strong inclusion complex, beta-CD co-concentrated during cITP sample stacking. However, once the focusing process was complete, a discrete diffusional boundary formed between the cITP-focused analyte band and the leading and trailing electrolyte, which restricted diffusion into and out of the analyte band.

  2. Comparison of CAP88 PC Ver. 3.0 and MAXDOSE dose assessment models involving co-located stack releases at the Savannah River site.

    PubMed

    Farfán, Eduardo; Jannik, G Timothy; Lee, Patricia; Powell, Aaron

    2013-08-01

    The Savannah River National Laboratory's Environmental Dosimetry Group performs dosimetry assessments for Savannah River Site (SRS) radionuclide air emissions utilizing the Clean Air Act Assessment Package-1988 (CAP88) code (CAP88 PC Ver. 3.0) and the MAXDOSE-SR Ver. 2011 code, which is an SRS-specific version of the Nuclear Regulatory Commission's MAXIGASP code. CAP88 PC and MAXDOSE-SR are used at SRS for demonstrating compliance with Environmental Protection Agency dose standards for radionuclide emissions to the atmosphere and Department of Energy Order 458.1 dose standards, respectively. During a routine comparison of these two assessment models, it was discovered that CAP88 PC Ver. 3.0 was not producing the expected results when using multiple co-located stacks in a single run. Specifically, if the stack heights are considered separately, the results for several radionuclides (but not all) differ from the combined run [i.e., 1 + 2 does not equal (1+2)]. Additionally, when two or more stack heights are considered in a run, the results depend on the order of the selected stack heights. For example, for a two stack-height run of 0 meter and 61 m input produces different results from a 61 m and 0 m input run. This study presents a comparison of CAP88 PC Ver. 3.0 and MAXDOSE-SR Ver. 2011 based on SRS input data and on two-stack release scenarios. The selected radionuclides for this study included gases/vapors (H, C, Kr, and I) and particulates (Sr, Cs, Pu, and Am) commonly encountered at SRS.

  3. Measurement of the Tracer Gradient and Sampling System Bias of the Hot Fuel Examination Facility Stack Air Monitoring System

    SciTech Connect

    Glissmeyer, John A.; Flaherty, Julia E.

    2011-07-20

    This report describes tracer gas uniformity and bias measurements made in the exhaust air discharge of the Hot Fuel Examination Facility at Idaho National Laboratory. The measurements were a follow-up on earlier measurements which indicated a lack of mixing of the two ventilation streams being discharged via a common stack. The lack of mixing is detrimental to the accuracy of air emission measurements. The lack of mixing was confirmed in these new measurements. The air sampling probe was found to be out of alignment and that was corrected. The suspected sampling bias in the air sample stream was disproved.

  4. Suitability of air sampling locations downstream of bends and static mixing elements.

    PubMed

    McFarland, A R; Gupta, R; Anand, N K

    1999-12-01

    The revised standard for sampling effluent air from stacks and ducts of the nuclear industry places limits on the non-uniformity of velocity and contaminant profiles at the sampling location; namely, the coefficients of variation must not exceed 20% over an area that encompasses at least the center 2/3 of the cross sectional area. Tests were conducted to characterize the degree of mixing at downstream locations as affected by several types of flow disturbances, including 90 degree elbows and commercial static mixing devices. Flow straighteners were incorporated into the ducting upstream of the mixer to be tested to simulate the dampening of flow turbulence that might occur because of upstream HEPA filters. The coefficients of variation of velocity and tracer gas concentration measured in a straight tube at a distance of 3 diameters downstream from a 90 degree elbow were 17% and 69%, respectively. The mixing is impacted by the upstream flow turbulence. Without a flow straightener, the tracer gas concentration coefficient of variation was reduced to 33% at the 3-diameter location. The use of static mixing elements can greatly enhance the mixing process. A ring placed just downstream of a 90 degree elbow, which blocks the outer 56% of the cross sectional area, results in a coefficient of variation of 19% for tracer gas concentration at the 3-diameter location. Pressure loss across the elbow with the ring is about nine times that of the basic elbow. One of the commercially available static mixers provides coefficients of variation that are less than 10% for both velocity and tracer gas concentration at 4 diameters downstream from the mixer with a pressure loss that is only about 3.5 times as large as that of a 90 degree elbow.

  5. Nitrogen oxide stack sampling at the U.S. DOE Oak Ridge Y-12 Steam Plant

    SciTech Connect

    L.V. Gibson, jr.; M.P. Humphreys; J.M. Skinner

    2000-03-01

    On November 7, 1997, the EPA proposed a Nitrogen Oxides State Implementation Plan Call (NO{sub x} SIP Call) for 22 states in the Eastern US which included the state of Tennessee. This initial proposal was followed by proposed statewide NO{sub x} budgets in the May 11, 1998, Supplemental Notice of Proposed Rulemaking. In the development of the NO{sub x} SIP Call, EPA performed a number of air quality analyses and determined that NO{sub x} emissions from Tennessee should be reduced. Industrial boilers, turbines, stationary internal combustion engines, and cement manufacturing are the only non-electric generating unit sources for which reductions are assumed in the budget calculation. Emission reductions are required if specific source heat input capacity is greater than 250 million Btu per hour. The US Department of Energy (DOE) Oak Ridge Y-12 Steam Plant consists of four Wickes pulverized coal fired boilers each rated at a maximum heat input capacity of 298 million Btu per hour, and will therefore be impacted by these regulatory actions. Each boiler is equipped with two pulverizing mills. Coal or natural gas or a combination of these two fuels may be fired. This paper provides the results of NO{sub x} emission stack testing conducted June 15--21, 1999, on the Y-12 Steam Plant Boilers 1 and 2. Measurements of oxygen (O{sub 2}), carbon monoxide (CO), carbon dioxide (CO{sub 2}), and stack gas flow were also performed. Information gained from these stack tests will be used to determine NO{sub x} emission control strategies for the steam plant for compliance with future emission requirements resulting from the NO{sub x} SIP Call.

  6. Comparative study on sample stacking by moving reaction boundary formed with weak acid and weak or strong base in capillary electrophoresis: II. Experiments.

    PubMed

    Zhang, Wei; Fan, Liuyin; Shao, Jing; Li, Si; Li, Shan; Cao, Chengxi

    2011-04-15

    To demonstrate the theoretic method on the stacking of zwitterion with moving reaction boundary (MRB) in the accompanying paper, the relevant experiments were performed. The experimental results quantitatively show that (1) MRB velocity, including the comparisons between MRB and zwitterionic velocities, possesses key importance to the design of MRB stacking; (2) a much long front alkaline plug without sample should be injected before the sample injection for a complete stacking of zwitterion if sample buffer is prepared with strong base, conversely no such plug is needed if using a weak base as the sample buffer with proper concentration and pH value; (3) the presence of salt in MRB system holds dramatic effect on the MRB stacking if sample solution is a strong base, but has no effect if a weak alkali is used as sample solution; (4) all of the experiments of this paper, including the previous work, quantitatively manifest the theory and predictions shown in the accompanying paper. In addition, the so-called derivative MRB-induced re-stacking and transient FASI-induced re-stacking were also observed during the experiments, and the relevant mechanisms were briefly demonstrated with the results. The theory and its calculation procedures developed in the accompanying paper can be well used for the predictions to the MRB stacking of zwitterion in CE.

  7. Permutation Tests for Common Locations among Samples with Unequal Variances.

    ERIC Educational Resources Information Center

    Mielke, Paul W., Jr.; Berry, Kenneth J.

    1994-01-01

    Presents permutation procedures that jointly test for differences in location and scale among treatments in a completely randomized experimental design. Also considers extensions to multivariate data and provides efficient alternative permutation tests. (SLD)

  8. Cloud point sample clean-up and capillary zone electrophoresis with field enhanced sample injection and micelle to solvent stacking for the analysis of herbicides in milk.

    PubMed

    Kukusamude, Chunyapuk; Srijaranai, Supalax; Kato, Masaru; Quirino, Joselito P

    2014-07-18

    Sample clean-up by cloud point phase separation and analysis by capillary electrophoresis with stacking was developed for quaternary ammonium herbicides (i.e., paraquat and diquat) in milk. For sample clean-up, a mixture of 845μL of milk sample, 5μL of 100mM phosphoric acid, and 150μL of Triton X-114 was heated (60°C for 2min) and centrifugated (3000rpm for 2min) in 2-mL Eppendorf tube. The upper phase was directly analysed by capillary electrophoresis via electrokinetic injection at 10kV for 150s. The separation electrolyte was 100mM phosphate buffer with 20% acetonitrile at pH 2.5. Before sample injection, a micellar solution (10mM SDS in 80mM phosphate buffer at pH 2.5) and an organic solvent rich solution (30% ACN) was hydrodynamically introduced into the capillary. These solutions provided the necessary conditions for stacking the cationic herbicides via the combination of field enhanced sample injection and micelle to solvent stacking. The LODs (S/N=3) obtained from the entire strategy for paraquat and diquat in milk was 0.004 and 0.018μg/mL, respectively. This is 1.5 to >2 orders of magnitude better than the corresponding LODs obtained from the electrophoretic analysis of herbicide standards prepared in the separation electrolyte. The strategy was also successfully applied to 5 milk samples available in the market. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  9. Solid-phase extraction and sample stacking-capillary electrophoresis for the determination of quaternary ammonium herbicides in drinking water.

    PubMed

    Núñez, O; Moyano, E; Galceran, M T

    2002-02-08

    Conditions for the simultaneous determination of paraquat, diquat and difenzoquat by capillary zone electrophoresis were established by combining two preconcentration procedures. Off-line solid-phase extraction was used for the isolation and preconcentration of quats in drinking water. Quats were then analysed by capillary electrophoresis using sample stacking with matrix removal as on-column preconcentration procedure. Two different porous graphitic carbon cartridges were compared. The breakthrough volumes of the three herbicides were calculated and the loading capacity of the sorbents was compared. Recoveries higher than 80% for difenzoquat and around 40% for paraquat and diquat were obtained when a sample volume of 250 ml was percolated. For the stacking-capillary electrophoresis analysis of quats, 50 mM acetic acid-ammonium acetate (pH 4.0), 0.8 mM cetyltrimethylammonium bromide with 5% (v/v) methanol as carrier electrolyte was used. Detection limits, based on a signal-to-noise ratio of 3:1, were lower than 0.3 microg l(-1) for standards in Milli-Q water, and lower than 2.2 microg l(-1) for drinking water samples. Run-to-run and day-to-day precision of the method were established. The two preconcentration procedures used together was successfully applied to the analysis of the three herbicides in spiked drinking water at concentrations below the maximum admissible US Environmental Protection Agency levels.

  10. Sensitive determination of sertraline by capillary electrophoresis with dispersive liquid-liquid microextraction and field-amplified sample stacking.

    PubMed

    Huang, Shiou-Wen; Hsieh, Ming-Mu; Chang, Sarah Y

    2012-11-15

    A novel method for the determination of sertraline using dispersive liquid-liquid microextraction (DLLME) coupled with capillary electrophoresis (CE) was developed. Acetone and dichloromethane were used as the disperser solvent and extraction solvent, respectively. A mixture of the extraction and disperser solvents was rapidly injected into a 1.0 mL aqueous sample to form a cloudy solution. After the extraction, sertraline was analyzed using CE that was equipped with UV detection. A 74-fold improvement in the sensitivity was observed when DLLME was used to extract sertraline. Since the DLLME extract residue was redissolved with 5 μL of water that contained 20% methanol, the detection sensitivity was further enhanced through the use of field-amplified sample stacking (FASS). A 11-fold improvement in the sensitivity was obtained when FASS was used to on-line concentrate sertraline. Under optimal extraction and stacking conditions, the calibration curve, which ranged from 0.01 to 1 μM was observed to be linear. The limit of detection (LOD) at a signal-to-noise ratio of 3 was 2.5 nM for sertraline. An approximately 814-fold improvement in the sensitivity was observed for sertraline compare with injection of standard solution without the DLLME and FASS procedures. This developed method was successfully applied to the determination of sertraline in human urine samples.

  11. Building Extraction Based on an Optimized Stacked Sparse Autoencoder of Structure and Training Samples Using LIDAR DSM and Optical Images.

    PubMed

    Yan, Yiming; Tan, Zhichao; Su, Nan; Zhao, Chunhui

    2017-08-24

    In this paper, a building extraction method is proposed based on a stacked sparse autoencoder with an optimized structure and training samples. Building extraction plays an important role in urban construction and planning. However, some negative effects will reduce the accuracy of extraction, such as exceeding resolution, bad correction and terrain influence. Data collected by multiple sensors, as light detection and ranging (LIDAR), optical sensor etc., are used to improve the extraction. Using digital surface model (DSM) obtained from LIDAR data and optical images, traditional method can improve the extraction effect to a certain extent, but there are some defects in feature extraction. Since stacked sparse autoencoder (SSAE) neural network can learn the essential characteristics of the data in depth, SSAE was employed to extract buildings from the combined DSM data and optical image. A better setting strategy of SSAE network structure is given, and an idea of setting the number and proportion of training samples for better training of SSAE was presented. The optical data and DSM were combined as input of the optimized SSAE, and after training by an optimized samples, the appropriate network structure can extract buildings with great accuracy and has good robustness.

  12. Sensitive determination of barbiturates in biological matrix by capillary electrophoresis using online large-volume sample stacking.

    PubMed

    Fan, Liu-Yin; He, Ting; Tang, Yun-Yun; Zhang, Wei; Song, Chao-Jin; Zhao, Xia; Zhao, Xiao-Yu; Cao, Cheng-Xi

    2012-05-01

    In China, some forensic cases are caused by barbiturates. Thus, the determination of trace level barbiturates in body fluid is important for the poisoning investigation. In this study, an online large-volume sample stacking (LVSS) with polarity switching in capillary electrophoresis (CE) was applied for the sensitive determination of barbiturates. This technique involves injecting a large volume of sample into a capillary and removing the sample matrix plug out of the capillary by reversing the polarity. Quantitation limit obtained was 0.048, 0.057, 0.039, and 0.015 μg/mL for secobarbital, amobarbital, barbital, and phenobarbital (signal-to-noise ratio = 9). By using LVSS, the stacking was simply achieved at 171.7-, 169.7-, 202.7-, and 169.1-fold for the above four barbiturates. The relative standard deviation values of intraday and interday were <2.11% and 4.69%, respectively. Recoveries were ranged from 83.7 to 105.2%. Finally, the trace analysis method was applied to the analysis of real forensic specimens and has achieved satisfactory results. © 2012 American Academy of Forensic Sciences.

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

    SciTech Connect

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

    2011-01-18

    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.

  14. Comparative study on sample stacking by moving reaction boundary formed with weak acid and weak or strong alkali in capillary electrophoresis: I. Theory.

    PubMed

    Cao, Chengxi; Zhang, Wei; Fan, Liuyin; Shao, Jing; Li, Si

    2011-05-15

    The condensation of low abundance zwitterion substance, such as protein and peptide, has great significance to the study on proteomics. This paper develops the theory on design of online stacking conditions of zwitterion by a moving reaction boundary (MRB) in capillary electrophoresis (CE). This concerns the choice of running and sample buffers, velocity design of MRB, and salt effect on the stacking. The theoretical results unveil that: (1) the velocity of MRB formed with weak acidic buffer and strong alkali should be set between zero and the velocity of zwitterion in the alkali phase, or no stacking occurs; (2) if a strong alkali is used to prepare the sample, a much long front plug of strong base must be injected before the alkaline sample plug for complete stacking, whereas no such front plug is needed if a weak alkali with enough high concentration and pH value is used to prepare the sample buffer; (3) the existence of salt in sample matrix has a weak effect on the stacking of zwitterion if sample is prepared with weak alkaline buffer, while has a dramatic effect on the same stacking if with a strong base buffer. In addition, the concentration of weak alkali used for preparation of sample should be set at the point, at which the velocity of MRB is as much as possible close to that of negative zwitterion. The developed theory and its computation are quantitatively proved by the experiments of zwitterion stacking by the MRB as shown in the previous and the accompanying papers. The proposed theoretic results hold obvious significances on-column stacking of low abundance zwitterions, such as amino acid, or peptides or proteins, in CE.

  15. 40 CFR 761.304 - Determining sample location.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CONTROL ACT POLYCHLORINATED BIPHENYLS (PCBs) MANUFACTURING, PROCESSING, DISTRIBUTION IN COMMERCE, AND USE PROHIBITIONS Sampling Non-Porous Surfaces for Measurement-Based Use, Reuse, and On-Site or Off-Site Disposal... by 10 cm sampling position for each different 1 square meter surface in accordance with § 761.308....

  16. Exploration of CH···π mediated stacking interactions in saccharide: aromatic residue complexes through conformational sampling.

    PubMed

    Kumari, Manju; Sunoj, Raghavan B; Balaji, Petety V

    2012-11-01

    Saccharides interact with aromatic residues mostly through CH···π mediated stacking interactions. The energetics of such interactions depends upon the mutual position-orientations (POs) of the two moieties. The POs found in the crystal structures are only a subset of the various possible ways of interaction. Hence, potential energy surfaces of saccharide-aromatic residue complexes have been explored by mixed Monte Carlo multiple minimum/low mode sampling. The saccharides considered in this study are α/β-D-glucose, β-D-galactose, α-D-mannose, and α/β-L-fucose. p-Hydroxytoluene, toluene, and 3-methylindole were used as analogs of tyrosine, phenylalanine, and tryptophan, respectively. The saccharides interact from either above or below the π-cloud of an aromatic ring but not along the edges. The POs preferred by different saccharides, both in the preferred chair and skew-boat forms, for interacting with different aromatic amino acid residue analogs have been identified. Aromatic residues can interact with the same -CH group in many POs but not so with the -OH groups. Changes in the configurations of pyranose ring carbon atoms cause remarkable changes in stacking preferences. β-D-Galactose and β-L-fructose interact only through their b- and a-faces, respectively. Saccharides use a wide variety of apolar patches for stacking against aromatic residues and these have been analyzed in detail. As many as four -CH groups can simultaneously participate in CH···π interactions, especially with 3-methylindole owing to its larger surface area.

  17. Map of National Aquatic Resource Surveys Sampling Locations

    EPA Pesticide Factsheets

    This map displays all of the lakes, rivers and streams, wetlands, and coastal waters sampled by the National Aquatic Resource Surveys, a collaborative EPA program that assesses the condition of the nation's waters using statistical designs.

  18. Measurement of vapor phase mercury emissions at coal-fired power plants using regular and speciating sorbent traps with in-stack and out-of-stack sampling methods

    SciTech Connect

    Chin-Min Cheng; Chien-Wei Chen; Jiashun Zhu; Chin-Wei Chen; Yao-Wen Kuo; Tung-Han Lin; Shu-Hsien Wen; Yong-Siang Zeng; Juei-Chun Liu; Wei-Ping Pan

    2009-09-15

    A systematic investigation of sorbent-trap sampling, which is a method that uses paired sorbent traps to measure total vapor phase mercury (Hg), was carried out at two coal-fired power plants. The objective of the study was to evaluate the effects (if any) on data quality when the following aspects of the sorbent trap method are varied: (a) sorbent trap configuration; (b) sampling time; and (c) analytical technique. Also, the performance of a speciating sorbent trap (i.e., a trap capable of separating elemental Hg from oxidized Hg), was evaluated by direct comparison against the Ontario Hydro (OH) reference method. Flue gas samples were taken using both 'regular' and modified sorbent trap measurement systems. Both short-term (1.5 h) and long-term (18 h to 10 days) samples were collected. The in-stack and out-of-stack sampling methods produced satisfactory relative accuracy results for both the short-term and long-term testing. For the short-term tests, the in-stack sampling results compared more favorably to the OH method than did the out-of-stack results. The relative deviation between the paired traps was considerably higher for the short-term out-of-stack tests than for the long-term tests. A one-way analysis of variance (ANOVA), showed a statistically significant difference (p < 0.1) between the direct combustion and wet-chemistry analytical methods used in the study; the results from the direct combustion method were consistently higher than the wet-chemistry results. The evaluation of the speciating mercury sorbent trap demonstrated that the trap is capable of providing reasonably accurate total mercury concentrations and speciation data that are somewhat comparable to data obtained with the OH method. 5 refs., 4 figs., 8 tabs.

  19. Sensitive determination of pyrrolizidine alkaloids in Tussilago farfara L. by field-amplified, sample-stacking, sweeping micellar electrokinetic chromatography.

    PubMed

    Cao, Kun; Xu, Yi; Mu, Xiuni; Zhang, Qing; Wang, Renjie; Lv, Junjiang

    2016-11-01

    Pyrrolizidine alkaloids are the toxic components in Tussilago farfara L. Due to the lack of standard substances for quantitative analysis and traces of pyrrolizidine alkaloids in total alkaloids, the full quality control of Tussilago farfara L has been limited. In this study, we aimed to solve the difficulty of determination of pyrrolizidine alkaloids and identify more components in the total alkaloids. An on-line preconcentration method has been applied to improve determining sensitivity of pyrrolizidine alkaloids in Tussilago farfara L. in which included field-amplified sample stacking and sweeping in micellar electrokinetic capillary chromatography. The main parameters that affected separation and stacking efficiency were investigated in details. Under the optimal conditions, the sensitivity enhancement factors obtained by the developed method for the analytes were from 15- to 12-fold, the limits of detection of senkirkine and senecionine were 2∼5 μg/L. Senkirkine and senecionine have been detected in alkaloids (c) of Tussilago farfara L, along ferulic acid methyl ester and methyl caffeate. The developed method was also applied to the analysis of acid extraction (a) of Tussilago farfara L, and senkirkine could be detected directly. The results indicated that the developed method is feasible for the analysis of pyrrolizidine alkaloids in Tussilago farfara L with good recoveries.

  20. Field-amplified sample stacking capillary electrophoresis with electrochemiluminescence applied to the determination of illicit drugs on banknotes.

    PubMed

    Xu, Yuanhong; Gao, Ying; Wei, Hui; Du, Yan; Wang, Erkang

    2006-05-19

    Capillary electrophoresis (CE) with Ru(bpy)3(2+) electrochemiluminescence (ECL) detection system was established to the determination of contamination of banknotes with controlled drugs and a high efficiency on-column field-amplified sample stacking (FASS) technique was also optimized to increase the ECL intensity. The method was illustrated using heroin and cocaine, which are two typical and popular illicit drugs. Highest sample stacking was obtained when 0.01 mM acetic acid was chosen for sample dissolution with electrokinetical injection for 6 s at 17 kV. Under the optimized conditions: ECL detection at 1.2 V, separation voltage 10.0 kV, 20 mM phosphate-acetate (pH 7.2) as running buffer, 5 mM Ru(bpy)3(2+) with 50 mM phosphate-acetate (pH 7.2) in the detection cell, the standard curves were linear in the range of 7.50x10(-8) to 1.00x10(-5) M for heroin and 2.50x10(-7) to 1.00x10(-4) M for cocaine and detection limits of 50 nM for heroin and 60 nM for cocaine were achieved (S/N = 3), respectively. Relative standard derivations of the ECL intensity and the migration time were 3.50 and 0.51% for heroin and 4.44 and 0.12% for cocaine, respectively. The developed method was successfully applied to the determination of heroin and cocaine on illicit drug contaminated banknotes without any damage of the paper currency. A baseline resolution for heroin and cocaine was achieved within 6 min.

  1. Preliminary field evaluation of EPA Method CTM-039 (PM2.5 Stack Sampling Method)

    USDA-ARS?s Scientific Manuscript database

    Agricultural operations are encountering difficulties complying with current air pollution regulations for particulate matter (PM). These regulations are based on the National Ambient Air Quality Standards which set maximum concentration limits for ambient air PM. Source sampling for compliance purp...

  2. Update on field evaluation of EPA Method CTM-039 (PM2.5 Stack Sampling Method)

    USDA-ARS?s Scientific Manuscript database

    Agricultural operations are encountering difficulties complying with current air pollution regulations for particulate matter (PM). These regulations are based on the National Ambient Air Quality Standards, which set maximum concentration limits for ambient air PM. Source sampling for compliance pur...

  3. Capillary electrophoresis with field-amplified sample stacking for rapid and sensitive determination of sulfadiazine and sulfamethoxazole.

    PubMed

    Li, Yuqin; Cui, Yingjie; Jia, Baoxiu; Wang, Hao; Liu, Caihong; Qi, Yongxiu

    2012-09-01

    A new capillary electrophoresis method with field-amplified sample stacking (FASS) was developed for the analysis of sulfadiazine and sulfamethoxazole. After optimization of the separation and concentration conditions, the two compounds can be separated within 7 min and quantified with high sensitivity, with detection limits of 0.48 ng/mL for sulfadiazine and 0.76 ng/mL for sulfamethoxazole. This resulted in a 300-1500-fold improvement in concentration sensitivity relative to conventional capillary electrophoresis methods. The method was useful for qualitative and quantitative analysis of sulfadiazine and sulfamethoxazole in their preparations with recovery of 99.0%-102% for sulfadiazine and 99.5% - 99.7% for sulfamethoxazole.

  4. Determination of alkaloids in Sinomenium acutum by field-amplified sample stacking in capillary electrophoresis with chemiluminescene detection.

    PubMed

    Shi, Guiying; Li, Jiang; Yin, Yingchun; Xu, Xueqin; Chen, Guonan

    2013-01-01

    A simple and rapid capillary electrophoresis (CE) with an acidic potassium permanganate chemiluminescence (CL) detection method was developed to determine three alkaloids (curine, sinomenine and magnoflorine) simultaneously. A laboratory-built CE-CL detection interface was used. The field-amplified sample stacking technique was applied to the online concentration of alkaloids. Experimental conditions for CE separation and CL detection were investigated in detail to acquire optimum conditions. Under optimal conditions, the three alkaloids were baseline separated within 6 min, and the detection limits (S/N = 3) ranged from 0.03 µg/mL to 0.49 µg/mL. This method was successfully applied to determine the above three alkaloids in Sinomenium acutum, and the result of the determination of sinomenine was in good agreement with those given by high-performance liquid chromatography and CE methods. In addition, a possible CL reaction mechanism of sinomenine-KMnO4-H2SO4 was proposed.

  5. Determination of sildenafil citrate and its main metabolite by sample stacking with polarity switching using micellar electrokinetic chromatography.

    PubMed

    Berzas Nevado, J J; Flores, J Rodriguez; Peñalvo, G Castañeda; Rodríguez, Fariñas N

    2002-04-12

    Micellar electrokinetic capillary chromatography (MEKC) coupled with sample stacking and polarity switching was investigated for the determination of Viagra (sildenafil citrate, SC) and its metabolite (UK-103,320, UK) in human serum in the concentration range of clinical interest. Human serum samples spiked with SC and UK were eluted with methanol from a C18 cartridge, the extract was evaporated and regenerated in a solution that contained 1 mM phosphate buffer (pH 12.3) and 20% methanol. The MEKC separation was performed using an injection time of 275 s, a polarity switching time of 93 s, a phosphate buffer, (pH 12.3, 15 mM) containing 25 mM sodium dodecyl sulfate as separation electrolyte and a fused-silica capillary. The analysis takes about 6 min and gives satisfactory inter-day precision with respect to migration times and linear responses over the 80-900 ng/ml concentration range investigated for SC and UK. Intra-day RSDs (n=4 graphs) for the slopes of the calibration graphs were 4.86% for SC and 3.50% for UK. Inter-day RSDs for the slopes were 4.37% for SC and 5.39% for UK. Detection limits (S/N=3) were about 17 ng/ml for both compounds in human serum. A 1-ml volume of blood serum was necessary to do this determination.

  6. Rapid and sensitive determination of strychnine and brucine in human urine by capillary electrophoresis with field-amplified sample stacking.

    PubMed

    Li, Junmei; Jiang, Ye

    2010-02-01

    A simple, rapid, sensitive and low-cost method using capillary electrophoresis (CE) coupled with field-amplified sample stacking (FASS) has been developed and validated for the simultaneous determination of strychnine and brucine residues in human urine. Before sample loading, a water plug (3.5 kPa, 3 s) was injected to contain sample cations and to permit FASS. Electrokinetic injection at a voltage (20 kV, 25 s) was then used to introduce cations. Separation was performed using 20 mM acetate buffer (pH 3.8) with an applied voltage of 20 kV. The calibration curves were linear over a range of 8.00-2.56 infinity 10(2) ng/mL (r = 0.9995) for strychnine and 10.0-3.20 x 10(2) ng/mL (r = 0.9999) for brucine. Extraction recoveries in urine were greater than 79.6 and 82.8% for strychnine and brucine, respectively, with an RSD of less than 4.9%. The detection limits (signal-to-noise ratio 3) for strychnine and brucine were 2.00 and 2.50 ng/mL, respectively. A urine sample from one healthy female volunteer (26 years old, 50 kg) was pretreated and analyzed. Strychnine and brucine levels in urine could be detected 24 h after administration. On these grounds, this method was feasible for application to preliminary screening of trace levels of abused drugs for both doping control and forensic analysis. (c) 2009 John Wiley & Sons, Ltd.

  7. Field-amplified sample stacking capillary zone electrophoresis applied to the analysis of opiate drugs in hair.

    PubMed

    Manetto, G; Tagliaro, F; Crivellente, F; Pascali, V L; Marigo, M

    2000-08-01

    The present paper describes the methodological optimization and validation of capillary zone electrophoresis (CZE) for the determination of major opiates (morphine, codeine, 6-monoacetylmorphine, acetylcodeine, heroin) in hair samples by using a field-amplified sample stacking injection before the separation in a binary running buffer (0.1 M sodium phosphate, pH 2.5, with 40% ethylene glycol). The applied potential was 20 kV, at 25 degrees C. Detection was by UV absorption at the fixed wavelength of 214 nm or by recording the full spectrum between 190-400 nm, thus improving the analytical selectivity and identification power of CZE. Hair samples were liquid/liquid extracted; dried extracts, reconstituted with a low-conductivity solvent (0.1 mM phosphoric acid, with 80% 1-propanol), were injected by electromigration at 10 kV for 99 s, after a 0.5 mm plug of water. Under the described conditions, the limit of detection (with a signal-to-noise ratio of 3) in hair extracts was 100 pg/mL for codeine, 75 pg/mL for morphine and 6-monoacetylmorphine (6-MAM), 150 pg/mL for ethylmorphine, and 0.75 ng/mL for acetylcodeine and heroin. The precision of the method was validated for standards in pure solution by using internal standardization, providing for intraday and day-to-day assays, in terms of migration times, relative standard deviation (RSD) values < or = 0.2%, and in terms of peak areas, RSD values <5.71%.

  8. Reversible phospholipid nanogels for deoxyribonucleic acid fragment size determinations up to 1500 base pairs and integrated sample stacking.

    PubMed

    Durney, Brandon C; Bachert, Beth A; Sloane, Hillary S; Lukomski, Slawomir; Landers, James P; Holland, Lisa A

    2015-06-23

    of low viscosity. DNA sample stacking is facilitated with longer injection times without sacrificing separation efficiency. Copyright © 2015. Published by Elsevier B.V.

  9. Application of particle size distributions to total particulate stack samples to estimate PM2.5 and PM10 emission factors for agricultural sources

    USDA-ARS?s Scientific Manuscript database

    Particle size distributions (PSD) have long been used to more accurately estimate the PM10 fraction of total particulate matter (PM) stack samples taken from agricultural sources. These PSD analyses were typically conducted using a Coulter Counter with 50 micrometer aperture tube. With recent increa...

  10. Long-term sampling of dioxin-like substances from a clinker kiln stack using alternative fuels.

    PubMed

    Rivera-Austrui, J; Martinez, K; Marco-Almagro, L; Abalos, M; Abad, E

    2014-07-01

    The aim of this work is to characterize atmospheric emissions of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) from a cement production plant where the existing clinker production line was completely replaced by a new state-of-the-art installation. The project started in April 2008 with the installation of a long-term sampling system in the stack of the clinker kiln that used petroleum coke as fuel; PCDD/PCDF and dl-PCB emissions were then evaluated for a two year period. To carry out the second part of the study, in 2010 the sampling system was moved to the new installation in which, apart from conventional fuel, recovered derived fuel (RDF) and WWTP sludge were used as alternative fuels. For both the old and new clinker kilns, PCDD/PCDF emission values were well below the limit established by the European Waste Incineration Directive 2000/76/CE (EWID) of 100 pg I-TEQ/Nm(3); values ranged from 0.43 to 2.02 and from 0.07 to 3.31 pg I-TEQ/Nm(3), respectively. dl-PCBs accounted for approximately 25% of the WHO-TEQ toxicity. These results prove that the installation is capable of reducing PCDD/PCDF and dl-PCB emissions when alternative fuels are integrated into the process. In the case of PCDDs/PCDFs, the major contributions to total TEQ were usually from 2,3,7,8-TCDD (owing to its relative abundance) and 2,3,4,7,8-PeCDF (due to its high I-TEF of 0.5); while for dl-PCBs, the major contribution was from PCB-126. The slight shift in the congener profile between the old and new installations was characterized and a regression model was proposed for dl-PCB emissions depending on the RDF flow rate in the clinker.

  11. Simultaneous Separation of Eight Benzodiazepines in Human Urine Using Field-Amplified Sample Stacking Micellar Electrokinetic Chromatography.

    PubMed

    Oledzka, Ilona; Kulińska, Zofia; Prahl, Adam; Baczek, Tomasz

    2015-01-01

    A novel approach for the simultaneous quantification of eight benzodiazepines (BZDs) using dispersive liquid-liquid microextraction (DLLME) and field-amplified sample stacking (FASS) combined with micellar electrokinetic chromatography (MEKC) was investigated and evaluated in the context of precision, accuracy, sensitivity, linearity, detection and limits of quantification (LOQ). The absolute recovery rates of BZDs were above 90.65%. The limits of detection (LOD) were 20 ng/mL for chlordiazepoxide, estazolam, temazepam and midazolam, and 30 ng/mL for clonazepam, lorazepam, lormetazepam and medazepam, while the LOQ was set at 50 ng/mL for chlordiazepoxide, estazolam, temazepam and midazolam, and 100 ng/mL for clonazepam, lorazepam, lormetazepam and medazepam. Linearity was confirmed in the range of 50-2,000 ng/mL for chlordiazepoxide, estazolam, temazepam and midazolam, and 100-2,000 ng/mL for clonazepam, lorazepam, lormetazepam and medazepam, with a correlation coefficient greater than 0.9987 for all analytes. The elaborated procedure meets all the requirements of analytical methods. During the extraction procedure, a mixture of 1 mL of ethanol and 500 µL of dichloromethane, used as the disperser and extraction solvent, respectively, was rapidly injected into 3 mL of a urine sample. A significant improvement in sensitivity was achieved when DLLME was used to extract BZDs from the urine sample and FASS as an on-line preconcentration technique was developed. For the best separation of analytes, the running buffer was composed of 30 mM SDS, 10 mM sodium tetraborate and 15% methanol (pH 8.8), whereas a sample buffer was composed of 10 mM SDS and 2 mM sodium tetraborate. Moreover, a fused-silica capillary [inner diameter (i.d.) of 75 µm and length of 50 cm], photodiode array detection, pneumatic injection for 15 s and a voltage of 23 kV were applied. The applicability of the method has been confirmed for the analysis of BZD in urine samples collected from patients who

  12. Macromolecular differentiation of Golgi stacks in root tips of Arabidopsis and Nicotiana seedlings as visualized in high pressure frozen and freeze-substituted samples

    NASA Technical Reports Server (NTRS)

    Staehelin, L. A.; Giddings, T. H. Jr; Kiss, J. Z.; Sack, F. D.

    1990-01-01

    The plant root tip represents a fascinating model system for studying changes in Golgi stack architecture associated with the developmental progression of meristematic cells to gravity sensing columella cells, and finally to "young" and "old", polysaccharide-slime secreting peripheral cells. To this end we have used high pressure freezing in conjunction with freeze-substitution techniques to follow developmental changes in the macromolecular organization of Golgi stacks in root tips of Arabidopsis and Nicotiana. Due to the much improved structural preservation of all cells under investigation, our electron micrographs reveal both several novel structural features common to all Golgi stacks, as well as characteristic differences in morphology between Golgi stacks of different cell types. Common to all Golgi stacks are clear and discrete differences in staining patterns and width of cis, medial and trans cisternae. Cis cisternae have the widest lumina (approximately 30 nm) and are the least stained. Medial cisternae are narrower (approximately 20 nm) and filled with more darkly staining products. Most trans cisternae possess a completely collapsed lumen in their central domain, giving rise to a 4-6 nm wide dark line in cross-sectional views. Numerous vesicles associated with the cisternal margins carry a non-clathrin type of coat. A trans Golgi network with clathrin coated vesicles is associated with all Golgi stacks except those of old peripheral cells. It is easily distinguished from trans cisternae by its blebbing morphology and staining pattern. The zone of ribosome exclusion includes both the Golgi stack and the trans Golgi network. Intercisternal elements are located exclusively between trans cisternae of columella and peripheral cells, but not meristematic cells. In older peripheral cells only trans cisternae exhibit slime-related staining. Golgi stacks possessing intercisternal elements also contain parallel rows of freeze-fracture particles in their trans

  13. Macromolecular differentiation of Golgi stacks in root tips of Arabidopsis and Nicotiana seedlings as visualized in high pressure frozen and freeze-substituted samples

    NASA Technical Reports Server (NTRS)

    Staehelin, L. A.; Giddings, T. H. Jr; Kiss, J. Z.; Sack, F. D.

    1990-01-01

    The plant root tip represents a fascinating model system for studying changes in Golgi stack architecture associated with the developmental progression of meristematic cells to gravity sensing columella cells, and finally to "young" and "old", polysaccharide-slime secreting peripheral cells. To this end we have used high pressure freezing in conjunction with freeze-substitution techniques to follow developmental changes in the macromolecular organization of Golgi stacks in root tips of Arabidopsis and Nicotiana. Due to the much improved structural preservation of all cells under investigation, our electron micrographs reveal both several novel structural features common to all Golgi stacks, as well as characteristic differences in morphology between Golgi stacks of different cell types. Common to all Golgi stacks are clear and discrete differences in staining patterns and width of cis, medial and trans cisternae. Cis cisternae have the widest lumina (approximately 30 nm) and are the least stained. Medial cisternae are narrower (approximately 20 nm) and filled with more darkly staining products. Most trans cisternae possess a completely collapsed lumen in their central domain, giving rise to a 4-6 nm wide dark line in cross-sectional views. Numerous vesicles associated with the cisternal margins carry a non-clathrin type of coat. A trans Golgi network with clathrin coated vesicles is associated with all Golgi stacks except those of old peripheral cells. It is easily distinguished from trans cisternae by its blebbing morphology and staining pattern. The zone of ribosome exclusion includes both the Golgi stack and the trans Golgi network. Intercisternal elements are located exclusively between trans cisternae of columella and peripheral cells, but not meristematic cells. In older peripheral cells only trans cisternae exhibit slime-related staining. Golgi stacks possessing intercisternal elements also contain parallel rows of freeze-fracture particles in their trans

  14. Symmetry in the pigeon with sample and comparison stimuli in different locations. II.

    PubMed

    Swisher, Melissa; Urcuioli, Peter J

    2015-09-01

    Pigeons were trained on arbitrary (hue-form) and identity (hue-hue and form-form) successive matching with center-key samples and left-key comparisons. Later, they were tested on form-hue (symmetry) probe trials that were structured either in the different-locations fashion as the baseline trials (viz., center-key samples and left-key comparisons) or with a constant location by using center-key samples and center-key comparisons. Three of four pigeons showed symmetry when the probe-trial samples and comparisons appeared in center- and left-key spatial locations, respectively, but none did when both appeared in one (center-key) location. Subsequently, pigeons previously tested with center-key samples and left-key comparisons were tested with those form-hue stimuli shown in the same (center-key) location, and vice versa for the other pigeons. None of the former pigeons showed symmetry on the second test even if they had on the first test. By contrast, two of three pigeons that had not shown symmetry with single-location samples and comparisons did so when those stimuli appeared in different (center- vs. left-key) locations. Taken together, these results show that symmetrical relations between the same, nominal matching stimuli depend on where those stimuli appear in testing vis-à-vis in training and, more generally, confirm that spatial location is part of the functional matching stimuli.

  15. Statistical methods for the analysis of time-location sampling data.

    PubMed

    Karon, John M; Wejnert, Cyprian

    2012-06-01

    Time-location sampling (TLS) is useful for collecting information on a hard-to-reach population (such as men who have sex with men [MSM]) by sampling locations where persons of interest can be found, and then sampling those who attend. These studies have typically been analyzed as a simple random sample (SRS) from the population of interest. If this population is the source population, as we assume here, such an analysis is likely to be biased, because it ignores possible associations between outcomes of interest and frequency of attendance at the locations sampled, and is likely to underestimate the uncertainty in the estimates, as a result of ignoring both the clustering within locations and the variation in the probability of sampling among members of the population who attend sampling locations. We propose that TLS data be analyzed as a two-stage sample survey using a simple weighting procedure based on the inverse of the approximate probability that a person was sampled and using sample survey analysis software to estimate the standard errors of estimates (to account for the effects of clustering within the first stage [locations] and variation in the weights). We use data from the Young Men's Survey Phase II, a study of MSM, to show that, compared with an analysis assuming a SRS, weighting can affect point prevalence estimates and estimates of associations and that weighting and clustering can substantially increase estimates of standard errors. We describe data on location attendance that would yield improved estimates of weights. We comment on the advantages and disadvantages of TLS and respondent-driven sampling.

  16. Sampling location, herd size, and season influence Mycobacterium avium ssp. paratuberculosis environmental culture results.

    PubMed

    Wolf, R; Barkema, H W; De Buck, J; Orsel, K

    2015-01-01

    Mycobacterium avium subspecies paratuberculosis (MAP), the etiologic agent of Johne's disease, a chronic progressive enteritis, is a common pathogen on dairy farms. Environmental sampling is frequently used to detect MAP-infected herds, because it does not require sample collection from individual animals. The objectives were to determine (1) location-specific odds of MAP-positive environmental sampling results and whether season or herd size affect results; (2) whether season and herd size affect the odds of collection of samples from certain locations; and (3) whether sample-set composition affects the odds of a positive set. Herd veterinarians, producer organization staff, and University of Calgary staff collected 5,588 samples on dairy farms in Alberta and Saskatchewan. Samples from sick-cow and calving pens and samples from dry-cow housing had lower odds of testing MAP-positive than lactating cow-pen samples (odds ratio=0.3 and 0.4, respectively). Samples collected from bedding packs and manure piles were less frequently MAP-positive than those collected from alleyways and lagoons, whereas samples collected in spring and summer more often tested MAP-positive than those collected in winter. Sample sets collected in summer more often included samples from all locations than samples collected in winter; therefore, we inferred that collectors had difficulties accessing certain areas in winter. Substitution of sample locations with others had minor effect on the sensitivity of sample sets containing 6 samples. However, set composition had an effect on the sensitivity of sample sets containing only 2 samples. In that regard, whereas sets with 2 manure-storage-area samples detected 81% of farms with at least one positive environmental sample, sets with only dry, sick, or calving-pen samples detected only 59%. Environmental samples should be collected from areas where manure from numerous cows accumulates and can be well mixed (e.g., alleyways and manure lagoons

  17. Insights into head-column field-amplified sample stacking: Part I. Detailed study of electrokinetic injection of a weak base across a short water plug.

    PubMed

    Šesták, Jozef; Thormann, Wolfgang

    2017-06-16

    The fundamentals of electrokinetic injection of the weak base methadone across a short water plug into a phosphate buffer at low pH were studied experimentally and with computer simulation. The current during electrokinetic injection, the formation of the analyte zone, changes occurring within and around the water plug and mass transport of all compounds in the electric field were investigated. The impact of water plug length, plug injection velocity, and composition of sample, plug and background electrolyte are discussed. Experimental data revealed that properties of sample, water plug and stacking boundary are significantly and rapidly altered during electrokinetic injection. Simulation provided insight into these changes, including the nature of the migrating boundaries and the stacking of methadone at the interface to a newly formed phosphoric acid zone. The data confirm the role of the water plug to prevent contamination of the sample by components of the background electrolyte and suggest that mixing caused by electrohydrodynamic instabilities increases the water plug conductivity. The sample conductivity must be controlled by addition of an acid to prevent generation of reversed flow which removes the water plug and to create a buffering environment. Results revealed that a large increase in background electrolyte concentration is not accompanied with a significant increase in stacking. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Map showing locations of samples dated by radiocarbon methods in the San Francisco Bay region

    USGS Publications Warehouse

    Wright, Robert H.

    1971-01-01

    The potential value of a radiocarbon date is diminished, however, if adequate site data are not taken with the sample and do not accompany the date in publication.  At a minimum, published dates should include an accurate location for the dated sample, type of material dated and method of dating, nature of the site, depth below surface (or other accurately defined datum) of date sample, stratigraphy of material overlying date sample, and the significance of the data in the study.

  19. An evaluation of potential sampling locations in a reservoir with emphasis on conserved spatial correlation structure.

    PubMed

    Yenilmez, Firdes; Düzgün, Sebnem; Aksoy, Aysegül

    2015-01-01

    In this study, kernel density estimation (KDE) was coupled with ordinary two-dimensional kriging (OK) to reduce the number of sampling locations in measurement and kriging of dissolved oxygen (DO) concentrations in Porsuk Dam Reservoir (PDR). Conservation of the spatial correlation structure in the DO distribution was a target. KDE was used as a tool to aid in identification of the sampling locations that would be removed from the sampling network in order to decrease the total number of samples. Accordingly, several networks were generated in which sampling locations were reduced from 65 to 10 in increments of 4 or 5 points at a time based on kernel density maps. DO variograms were constructed, and DO values in PDR were kriged. Performance of the networks in DO estimations were evaluated through various error metrics, standard error maps (SEM), and whether the spatial correlation structure was conserved or not. Results indicated that smaller number of sampling points resulted in loss of information in regard to spatial correlation structure in DO. The minimum representative sampling points for PDR was 35. Efficacy of the sampling location selection method was tested against the networks generated by experts. It was shown that the evaluation approach proposed in this study provided a better sampling network design in which the spatial correlation structure of DO was sustained for kriging.

  20. A method to optimize sampling locations for measuring indoor air distributions

    NASA Astrophysics Data System (ADS)

    Huang, Yan; Shen, Xiong; Li, Jianmin; Li, Bingye; Duan, Ran; Lin, Chao-Hsin; Liu, Junjie; Chen, Qingyan

    2015-02-01

    Indoor air distributions, such as the distributions of air temperature, air velocity, and contaminant concentrations, are very important to occupants' health and comfort in enclosed spaces. When point data is collected for interpolation to form field distributions, the sampling locations (the locations of the point sensors) have a significant effect on time invested, labor costs and measuring accuracy on field interpolation. This investigation compared two different sampling methods: the grid method and the gradient-based method, for determining sampling locations. The two methods were applied to obtain point air parameter data in an office room and in a section of an economy-class aircraft cabin. The point data obtained was then interpolated to form field distributions by the ordinary Kriging method. Our error analysis shows that the gradient-based sampling method has 32.6% smaller error of interpolation than the grid sampling method. We acquired the function between the interpolation errors and the sampling size (the number of sampling points). According to the function, the sampling size has an optimal value and the maximum sampling size can be determined by the sensor and system errors. This study recommends the gradient-based sampling method for measuring indoor air distributions.

  1. Map showing locations and statistical parameters of beach and offshore sand samples, Tutuila Island, American Samoa

    USGS Publications Warehouse

    Dingler, J.R.; Carlson, D.V.; Sallenger, A.H.

    1987-01-01

    In April 1985, sand samples were collected from many of the beaches on Tutuila Island, American Samoa, and in July 1985, three bays were surveyed using side-scan sonar and shallow seismic profiling. During that second trip, scuba divers collected sand samples from the surveyed areas. Dingler and others (1986) describes the study; this report presents the grain-size and composition data for the onshore and offshore sand samples. Locations of the onshore samples are plotted on the map of the island, which is reproduced from Normark and others (1985); locations of most of the offshore samples and side-scan sonar interpretations made during the study are plotted on enlargements (A and B, respectively) of Fagaitua and Nua-seetaga Bays. Lam Yuen (1981), U.S. Army Corps of Engineers (1980), and Sea Engineering Services Inc. (1980) provide additional information pertaining to the island's beaches.

  2. Determination of geostatistically representative sampling locations in Porsuk Dam Reservoir (Turkey)

    NASA Astrophysics Data System (ADS)

    Aksoy, A.; Yenilmez, F.; Duzgun, S.

    2013-12-01

    Several factors such as wind action, bathymetry and shape of a lake/reservoir, inflows, outflows, point and diffuse pollution sources result in spatial and temporal variations in water quality of lakes and reservoirs. The guides by the United Nations Environment Programme and the World Health Organization to design and implement water quality monitoring programs suggest that even a single monitoring station near the center or at the deepest part of a lake will be sufficient to observe long-term trends if there is good horizontal mixing. In stratified water bodies, several samples can be required. According to the guide of sampling and analysis under the Turkish Water Pollution Control Regulation, a minimum of five sampling locations should be employed to characterize the water quality in a reservoir or a lake. The European Union Water Framework Directive (2000/60/EC) states to select a sufficient number of monitoring sites to assess the magnitude and impact of point and diffuse sources and hydromorphological pressures in designing a monitoring program. Although existing regulations and guidelines include frameworks for the determination of sampling locations in surface waters, most of them do not specify a procedure in establishment of monitoring aims with representative sampling locations in lakes and reservoirs. In this study, geostatistical tools are used to determine the representative sampling locations in the Porsuk Dam Reservoir (PDR). Kernel density estimation and kriging were used in combination to select the representative sampling locations. Dissolved oxygen and specific conductivity were measured at 81 points. Sixteen of them were used for validation. In selection of the representative sampling locations, care was given to keep similar spatial structure in distributions of measured parameters. A procedure was proposed for that purpose. Results indicated that spatial structure was lost under 30 sampling points. This was as a result of varying water

  3. SYMMETRY IN THE PIGEON WITH SAMPLE AND COMPARISON STIMULI IN DIFFERENT LOCATIONS

    PubMed Central

    Swisher, Melissa; Urcuioli, Peter J.

    2017-01-01

    Pigeons typically do not show evidence for symmetry in two-alternative matching-to-sample but do demonstrate this emergent relation in successive (go/no-go) matching-to-sample. Because the sample and comparison stimuli are presented in the same spatial location (viz., on one key) during successive matching training and testing, this may be one reason why pigeons pass tests for symmetry in this paradigm. To evaluate this, one group of pigeons received successive matching training with hue-sample stimuli on the center key and form-comparison stimuli on the left key of a three-key chamber. A control group was trained with all stimuli appearing on the same (left) key. Training also involved concurrent hue- and form-identity successive matching with the same spatial location arrangement as each group’s respective hue–form task. Later, nonreinforced form–hue (symmetry) probes structured in the same way as the baseline trials were given. Of the six birds in each group, five trained with different locations and two trained with constant location responded more to the reverse of baseline positive hue–form combinations than to negative ones in testing. Results confirm the prediction from Urcuioli’s (2008) theory that symmetry should emerge even with varying spatial locations, as long as functional stimuli are held constant. PMID:23703090

  4. Determining Optimal Location and Numbers of Sample Transects for Characterization of UXO Sites

    SciTech Connect

    BILISOLY, ROGER L.; MCKENNA, SEAN A.

    2003-01-01

    Previous work on sample design has been focused on constructing designs for samples taken at point locations. Significantly less work has been done on sample design for data collected along transects. A review of approaches to point and transect sampling design shows that transects can be considered as a sequential set of point samples. Any two sampling designs can be compared through using each one to predict the value of the quantity being measured on a fixed reference grid. The quality of a design is quantified in two ways: computing either the sum or the product of the eigenvalues of the variance matrix of the prediction error. An important aspect of this analysis is that the reduction of the mean prediction error variance (MPEV) can be calculated for any proposed sample design, including one with straight and/or meandering transects, prior to taking those samples. This reduction in variance can be used as a ''stopping rule'' to determine when enough transect sampling has been completed on the site. Two approaches for the optimization of the transect locations are presented. The first minimizes the sum of the eigenvalues of the predictive error, and the second minimizes the product of these eigenvalues. Simulated annealing is used to identify transect locations that meet either of these objectives. This algorithm is applied to a hypothetical site to determine the optimal locations of two iterations of meandering transects given a previously existing straight transect. The MPEV calculation is also used on both a hypothetical site and on data collected at the Isleta Pueblo to evaluate its potential as a stopping rule. Results show that three or four rounds of systematic sampling with straight parallel transects covering 30 percent or less of the site, can reduce the initial MPEV by as much as 90 percent. The amount of reduction in MPEV can be used as a stopping rule, but the relationship between MPEV and the results of excavation versus no

  5. Use of space-filling curves to select sample locations in natural resource monitoring studies

    Treesearch

    Andrew Lister; Charles T. Scott

    2009-01-01

    The establishment of several large area monitoring networks over the past few decades has led to increased research into ways to spatially balance sample locations across the landscape. Many of these methods are well documented and have been used in the past with great success. In this paper, we present a method using geographic information systems (GIS) and fractals...

  6. Combining field-amplified sample stacking with moving reaction boundary electrophoresis on a paper chip for the preconcentration and separation of metal ions.

    PubMed

    Ouyang, Liangfei; Liu, Qian; Liang, Heng

    2017-02-01

    A common drawback of paper-based separation devices is their poor detection limit. In this study, we combined field-amplified sample stacking with moving reaction boundary electrophoresis on a paper chip with six array channels for the parallel separation and concentration of multiple samples. With a new hyphenated technique, the brown I2 from the Fe(3+) /I(-) oxidation-reduction reaction emerged near the boundary between the dilute ethylene diamine tetraacetic acid and potassium iodide and highly concentrated KCl solutions. For the separation and concentration of three components, Cr(3+) , Cu(2+) , and Fe(3+) , the Fe(3+) detection limit was improved at least 266-fold by comparing the hyphenated technique with moving reaction boundary electrophoresis. The detection limit of Fe(3+) was found to be as low as 0.34 ng (20 μM) on the paper chip. We also demonstrated the analysis of a real sample of four metal ions, with detection limits as follows: 0.16 μg Cr(3+) , 1.5 μg Ni(2+) , 0.64 μg Cu(2+) , and 1.5 μg Co(2+) . The synergy of field-amplified sample stacking and moving reaction boundary electrophoresis in the micron paper-based array channels dramatically improved the detection limit and throughput of paper-based electrophoresis.

  7. Sampling Males Who Inject Drugs in Haiphong, Vietnam: Comparison of Time-Location and Respondent-Driven Sampling Methods.

    PubMed

    Tran, Hoang Vu; Le, Linh-Vi N; Johnston, Lisa Grazina; Nadol, Patrick; Van Do, Anh; Tran, Ha Thi Thanh; Nguyen, Tuan Anh

    2015-08-01

    Accurate measurements of HIV prevalence and associated risk factors among hidden and high-risk groups are vital for program planning and implementation. However, only two sampling methods are purported to provide representative estimates for populations without sampling frames: time-location sampling (TLS) and respondent-driven sampling (RDS). Each method is subject to potential biases and questionable reliability. In this paper, we evaluate surveys designed to estimate HIV prevalence and associated risk factors among people who inject drugs (PWID) sampled through TLS versus RDS. In 2012, males aged ≥16 years who reported injecting drugs in the previous month and living in Haiphong, Vietnam, were sampled using TLS or RDS. Data from each survey were analyzed to compare HIV prevalence, related risk factors, socio-demographic characteristics, refusal estimates, and time and expenditures for field implementation. TLS (n = 432) and RDS (n = 415) produced similarly high estimates for HIV prevalence. Significantly lower proportions of PWID sampled through RDS received methadone treatment or met an outreach worker. Refusal estimates were lower for TLS than for RDS. Total expenditures per sample collected and number of person-days of staff effort were higher for TLS than for RDS. Both survey methods were successful in recruiting a diverse sample of PWID in Haiphong. In Vietnam, surveys of PWID are conducted throughout the country; although the refusal estimate was calculated to be much higher for RDS than TLS, RDS in Haiphong appeared to sample PWID with less exposure to services and required fewer financial and staff resources compared with TLS.

  8. Hydroxyl-radical-dependent DNA damage by ambient particulate matter from contrasting sampling locations

    SciTech Connect

    Shi Tingming; Duffin, Rodger; Borm, Paul J.A.; Li Hui; Weishaupt, Christel; Schins, Roel P.F. . E-mail: roel.schins@uni-duesseldorf.de

    2006-05-15

    Exposure to ambient particulate matter (PM) has been reported to be associated with increased respiratory, cardiovascular, and malignant lung disease. Previously we have shown that PM can induce oxidative DNA damage in A549 human lung epithelial cells. The aims of the present study were to investigate the variability of the DNA-damaging properties of PM sampled at different locations and times and to relate the observed effects to the hydroxyl-radical ({center_dot}OH)-generating activities of these samples. Weekly samples of coarse (10-2.5 {mu}m) and fine (<2.5 {mu}m) PM from four sites (Nordrheim Westfalen, Germany) were analyzed for hydrogen-peroxide-dependent {center_dot}OH formation using electron paramagnetic resonance and formation of 8-hydroxydeoxyguanosine (8-OHdG) in calf thymus DNA using an immuno-dot-blot assay. DNA strand breakage by fine PM in A549 human lung epithelial cells was quantified using the alkaline comet assay. Both PM size distribution fractions elicited {center_dot}OH generation and 8-OHdG formations in calf thymus DNA. Significantly higher {center_dot}OH generation was observed for PM sampled at urban/industrial locations and for coarse PM. Samples of fine PM also caused DNA strand breakage in A549 cells and this damage could be prevented using the hydroxyl-radical scavengers 5,5-dimethyl-1-pyrroline-N-oxide and dimethyl sulfoxide. The observed DNA strand breakage appeared to correlate with the hydroxyl-radical-generating capacities of the PM samples but with different profiles for rural versus urban/industrial samples. In conclusion, when considered at equal mass, {center_dot}OH formation of PM shows considerable variability with regard to the sampling location and time and is correlated with its ability to cause DNA damage.

  9. Combination of micelle collapse and field-amplified sample stacking in capillary electrophoresis for determination of trimethoprim and sulfamethoxazole in animal-originated foodstuffs.

    PubMed

    Liu, Lihong; Wan, Qian; Xu, Xiaoying; Duan, Shunshan; Yang, Chunli

    2017-03-15

    An on-line preconcentration method combining micelle to solvent stacking (MSS) with field-amplified sample stacking (FASS) was employed for the analysis of trimethoprim (TMP) and sulfamethoxazole (SMZ) by capillary zone electrophoresis (CZE). The optimized experimental conditions were as followings: (1) sample matrix, 10.0mM SDS-5% (v/v) methanol; (2) trapping solution (TS), 35mM H3PO4-60% acetonitrile (CH3CN); (3) running buffer, 30mM Na2HPO4 (pH=7.3); (4) sample solution volume, 168nL; TS volume, 168nL; and (5) 9kV voltage, 214nm UV detection. Under the optimized conditions, the limits of detection (LODs) for SMZ and TMP were 7.7 and 8.5ng/mL, and they were 301 and 329 times better compared to a typical injection, respectively. The contents of TMP and SMZ in animal foodstuffs such as dairy products, eggs and honey were analyzed, too. Recoveries of 80-104% were acquired with relative standard deviations of 0.5-5.4%. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. A convenient and sensitive method for haloacetic acid analysis in tap water by on-line field-amplified sample-stacking CE-ESI-MS.

    PubMed

    Hung, Sih-Hua; Her, Guor-Rong

    2013-11-01

    In this study, we propose a simple strategy based on flow injection and field-amplified sample-stacking CE-ESI-MS/MS to analyze haloacetic acids (HAAs) in tap water. Tap water was passed through a desalination cartridge before field-amplified sample-stacking CE-ESI-MS/MS analysis to reduce sample salinity. With this treatment, the signals of the HAAs increased 300- to 1400-fold. The LODs for tap water analysis were in the range of 10 to 100 ng/L, except for the LOD of monochloroacetic acid (1 μg/L in selected-ion monitoring mode detection). The proposed method is fast, convenient, and sensitive enough to perform on-line analysis of five HAAs in the tap water of Taipei City. Four HAAs, including trichloroacetic acid, dichloroacetic acid, dibromoacetic acid, and monobromoacetic acid, were detected at concentrations of approximately 1.74, 1.15, 0.16, and 0.15 ppb, respectively.

  11. Postmortem measurement of caffeine in bone marrow: influence of sample location and correlation with blood concentration.

    PubMed

    Cartiser, N; Bévalot, F; Chatenay, C; Le Meur, C; Gaillard, Y; Malicier, D; Guitton, J; Fanton, L

    2011-07-15

    Bone marrow (BM) analysis is of forensic interest in postmortem toxicological investigation in case of limited, unavailable or unusable blood samples. However, it remains difficult to determine whether a drug BM concentration is therapeutic or represents overdose, due to the lack of studies on this alternative matrix. Given the variations in BM composition in the body, sample location was suggested to be a relevant factor in assessing BM concentration. The aim of the present study was to compare postmortem caffeine concentrations in various BM sample locations and secondly to consider the correlation between BM and blood concentrations. Six BM samples (right and left side: proximal and medial femur and 5th rib) and a blood sample were collected from 21 forensic autopsies. Gas chromatography coupled to tandem mass spectrometry was performed. Blood caffeine concentrations ranged from 60 to 7591ng/mL. Femoral and rib BM concentrations ranged from 51 to 6171ng/g and 66 to 7280ng/g, respectively. Blood concentrations were always higher than BM concentrations. As a good correlation was demonstrated between blood and rib BM and between blood and the average of the four femoral BM concentrations, blood caffeine concentrations could be correctly extrapolated from BM concentrations. BM caffeine concentration was found to depend on sample location. Rib BM caffeine concentrations appeared to be systematically greater than averaged femur values and concentrations were much more variable between the 4 femur BM samples than between the 2 ribs. From a practical point of view, for caffeine analysis, rib BM appeared more relevant than femoral BM, which requires multisampling to overcome the concentration variability problem.

  12. Analysis of ten abused drugs in urine by large volume sample stacking-sweeping capillary electrophoresis with an experimental design strategy.

    PubMed

    Ho, Yu-Hsiang; Wang, Chun-Chi; Hsiao, Yu-Tzu; Ko, Wei-Kung; Wu, Shou-Mei

    2013-06-21

    A statistical tool equipped with Plackett-Burman design (PBD) and central composite design (CCD) was used for fast stacking analysis of ten frequently consumed drugs, namely codeine, morphine, methamphetamine, ketamine, alprazolam, clonazepam, diazepam, flunitrazepam, nitrazepam and oxazepam, by capillary electrophoresis (CE). This statistical design is expected to help quick analysis with few procedures, avoiding tedious work required because of the large number of variables or parameters. A large volume sample stacking (LVSS)-sweeping CE is developed for concentrating and analyzing the 10 abused drugs. First, phosphate buffer (50 mM, pH 2.3) containing methanol was filled into a capillary and then the extracted urine sample was loaded (1 psi, 200 s) to enhance sensitivity. The sweeping and separating steps were completed simultaneously by phosphate buffer (50 mM, pH 2.3) containing methanol and sodium dodecyl sulfate, within 15 min. Better resolution was obtained by the experimental design than the "one factor at a time" (OFAT) approach. During method validation, calibration plots were linear (r>0.998), over a range of 25-1500 ng/mL for the six benzodiazepines, methamphetamine and ketamine, and 50-3000 ng/mL for codeine and morphine. The RSD of precision and absolute RE of accuracy in intra-day and inter-day assays were below 14.54% and 16.61%, respectively. The minimum limits for detection (S/N=3) of analytes were in the range of 7.5-30 ng/mL. This stacking method increased sensitivity more than 200-fold and can be applied for detection of the presence of methamphetamine in an abuser's urine (3600 ng/mL), which was confirmed by GC-MS. The method is considered feasible for fast screening of abused drugs in urine.

  13. Remaining Sites Verification Package for the 100-F-46, 119-F Stack Sampling French Drain, Waste Site Reclassification Form 2008-021

    SciTech Connect

    J. M. Capron

    2008-08-08

    The 100-F-46 french drain consisted of a 1.5 to 3 m long, vertically buried, gravel-filled pipe that was approximately 1 m in diameter. Also included in this waste site was a 5 cm cast-iron pipeline that drained condensate from the 119-F Stack Sampling Building into the 100-F-46 french drain. In accordance with this evaluation, the confirmatory sampling results support a reclassification of this site to No Action. The current site conditions achieve the remedial action objectives and the corresponding remedial action goals established in the Remaining Sites ROD. The results of confirmatory sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.

  14. A novel fractionized sampling and stacking strategy for online hyphenation of solid-phase-based extraction to ultra-high performance liquid chromatography for ultrasensitive analysis.

    PubMed

    Pan, Jialiang; Huang, Yichun; Liu, Li; Hu, Yuling; Li, Gongke

    2013-11-05

    We have developed a novel ultrasensitive online analytical system which integrated solid-phase-based extraction (SPBE) techniques with ultra-high performance liquid chromatography (UPLC) based on a fractionized sampling and stacking (FSS) strategy. FSS was proposed as a novel peak compression strategy to prevent band broadening and distortion caused by excessive solvents with high elution strength, which has been a main obstacle to conjunction of sample preparation techniques with UPLC. Such a strategy was based on online dividing a sample solution into fractions by plugs of weak mobile phase, followed by head-column stacking process, aiming to obtain a quite sharp sample zone. FSS enables UPLC to tolerate much larger injection volume of solvents with high elution strength, which facilitates hyphenation of SPBE with UPLC without peak distortion or loss of sensitivity. On the basis above, an online SPBE-UPLC system was realized by FSS, and its applicability was preliminarily verified by the successful development of a sensitive solid phase extraction-FSS-UPLC method for the determination of triazines. Subsequently an integrated online system incorporating molecularly imprinted in-tube solid phase microextraction, derivatization and FSS-UPLC was developed for the analysis of ultra trace 24-epibrassinolide. The developed method was ultrasensitive with detection limit as low as 0.7 ng/L, and the linear range of the method was 3-5000 ng/L. The endogenous 24-epibrassinolide in pollen, flower and seed samples was determined, which showed satisfactory recoveries in the range of 81.2-116% and good precision with relative standard deviation (RSD) values between 4.7 and 9.7%. This online analytical method was sensitive, reliable, rapid and applicable to trace analysis in complex samples.

  15. Evaluation of the role of location and distance in recruitment in respondent-driven sampling.

    PubMed

    McCreesh, Nicky; Johnston, Lisa G; Copas, Andrew; Sonnenberg, Pam; Seeley, Janet; Hayes, Richard J; Frost, Simon D W; White, Richard G

    2011-10-18

    Respondent-driven sampling(RDS) is an increasingly widely used variant of a link tracing design for recruiting hidden populations. The role of the spatial distribution of the target population has not been robustly examined for RDS. We examine patterns of recruitment by location, and how they may have biased an RDS study findings. Total-population data were available on a range of characteristics on a population of 2402 male household-heads from an open cohort of 25 villages in rural Uganda. The locations of households were known a-priori. An RDS survey was carried out in this population, employing current RDS methods of sampling and statistical inference. There was little heterogeneity in the population by location. Data suggested more distant contacts were less likely to be reported, and therefore recruited, but if reported more distant contacts were as likely as closer contacts to be recruited. There was no evidence that closer proximity to a village meeting place was associated with probability of being recruited, however it was associated with a higher probability of recruiting a larger number of recruits. People living closer to an interview site were more likely to be recruited. Household location affected the overall probability of recruitment, and the probability of recruitment by a specific recruiter. Patterns of recruitment do not appear to have greatly biased estimates in this study. The observed patterns could result in bias in more geographically heterogeneous populations. Care is required in RDS studies when choosing the network size question and interview site location(s).

  16. Glucose-β-CD interaction assisted ACN field-amplified sample stacking in CZE for determination of trace amlodipine in beagle dog plasma.

    PubMed

    Li, Ji; Li, You; Zhang, Wenting; Chen, Zhao; Fan, Guorong

    2013-06-01

    A simple, sensitive and low-cost method using CE coupled with glucose-β-CD interaction assisted ACN stacking technique has been developed for quantification of trace amlodipine in dog plasma. The plasma samples were extracted with methyl tert-butyl ether. The separation was performed at 25°C in a 31.2 cm × 75 μm fused-silica capillary with an applied voltage of 15 kV. The BGE was composed of 6.25 mM borate/25 mM phosphate (pH 2.5) and 5 mg/mL glucose-β-CD. The detection wavelength was 200 nm. Because CD could diminish the interaction between drugs and matrix, and derivation groups of CD play an important role in separation performance, the effects of β-CD, and its derivatives on the separation were studied at several concentrations (0, 2.5, 5.0, 10.0 mg/mL). In this study, organic solvent field-amplified sample stacking technique in combination with glucose-β-CD enhanced the sensitivity about 60-70 folds and glucose-β-CD could effectively improve the peak shape. All the validation data, such as accuracy, precision extraction recovery, and stability, were within the required limits. The calibration curve was linear for amlodipine from 1 to 200 ng/mL. The method developed was successfully applied to the pharmacokinetic studies of amlodipine besylate in beagle dogs.

  17. Stacking Up

    ERIC Educational Resources Information Center

    Naylor, Jim

    2005-01-01

    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…

  18. Stacking Up

    ERIC Educational Resources Information Center

    Naylor, Jim

    2005-01-01

    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…

  19. Stack filter classifiers

    SciTech Connect

    Porter, Reid B; Hush, Don

    2009-01-01

    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.

  20. Capillary zone electrophoresis with field enhanced sample stacking as a tool for targeted metabolome analysis of adenine nucleotides and coenzymes in Paracoccus denitrificans.

    PubMed

    Musilová, Jindra; Sedlácek, Vojtech; Kucera, Igor; Glatz, Zdenek

    2009-07-01

    The main aim of this work was to demonstrate the applicability of capillary zone electrophoresis in combination with field enhanced sample stacking in targeted metabolome analyses of adenine nucleotides--AMP, ADP, ATP, coenzymes NAD(+), NADP(+) and their reduced forms in Paracoccus denitrificans. Sodium carbonate/hydrogencarbonate buffer (100 mM, pH 9.6) with the addition of beta-CD at a concentration of 10 mM was found to be an effective BGE for their separation within 20 min. Besides this, special attention was paid to the development of the procedure for the extraction of specific metabolites from the bacterium P. denitrificans. This procedure was not only optimised to achieve the highest metabolite yields but also to obtain a sample that was fully compatible with the online preconcetration strategy used. The developed methodology was finally applied in a study of the bacterium P. denitrificans at various stages of the active respiratory chain.

  1. Use of space-filling curves to select sample locations in natural resource monitoring studies.

    PubMed

    Lister, Andrew J; Scott, Charles T

    2009-02-01

    The establishment of several large area monitoring networks over the past few decades has led to increased research into ways to spatially balance sample locations across the landscape. Many of these methods are well documented and have been used in the past with great success. In this paper, we present a method using geographic information systems (GIS) and fractals to create a sampling frame, superimpose a tessellation and draw a sample. We present a case study that illustrates the technique and compares results to those from other methods using data from Voyageurs National Park in Minnesota. Our method compares favorably with results from a popular plot selection method, Generalized Random Tessellation Stratified Design, and offers several additional advantages, including ease of implementation, intuitive appeal, and the ability to maintain spatial balance by adding new plots in the event of an inaccessible plot encountered in the field.

  2. Water Quality Sampling Locations Along the Shoreline of the Columbia River, Hanford Site, Washington

    SciTech Connect

    Peterson, Robert E.; Patton, Gregory W.

    2009-12-14

    As environmental monitoring evolved on the Hanford Site, several different conventions were used to name or describe location information for various sampling sites along the Hanford Reach of the Columbia River. These methods range from handwritten descriptions in field notebooks to the use of modern electronic surveying equipment, such as Global Positioning System receivers. These diverse methods resulted in inconsistent archiving of analytical results in various electronic databases and published reports because of multiple names being used for the same site and inaccurate position data. This document provides listings of sampling sites that are associated with groundwater and river water sampling. The report identifies names and locations for sites associated with sampling: (a) near-river groundwater using aquifer sampling tubes; (b) riverbank springs and springs areas; (c) pore water collected from riverbed sediment; and (d) Columbia River water. Included in the listings are historical names used for a particular site and the best available geographic coordinates for the site, as of 2009. In an effort to create more consistency in the descriptive names used for water quality sampling sites, a naming convention is proposed in this document. The convention assumes that a unique identifier is assigned to each site that is monitored and that this identifier serves electronic database management requirements. The descriptive name is assigned for the convenience of the subsequent data user. As the historical database is used more intensively, this document may be revised as a consequence of discovering potential errors and also because of a need to gain consensus on the proposed naming convention for some water quality monitoring sites.

  3. A Procedure to Determine the Optimal Sensor Positions for Locating AE Sources in Rock Samples

    NASA Astrophysics Data System (ADS)

    Duca, S.; Occhiena, C.; Sambuelli, L.

    2015-03-01

    Within a research work aimed to better understand frost weathering mechanisms of rocks, laboratory tests have been designed to specifically assess a theoretical model of crack propagation due to ice segregation process in water-saturated and thermally microcracked cubic samples of Arolla gneiss. As the formation and growth of microcracks during freezing tests on rock material is accompanied by a sudden release of stored elastic energy, the propagation of elastic waves can be detected, at the laboratory scale, by acoustic emission (AE) sensors. The AE receiver array geometry is a sensitive factor influencing source location errors, for it can greatly amplify the effect of small measurement errors. Despite the large literature on the AE source location, little attention, to our knowledge, has been paid to the description of the experimental design phase. As a consequence, the criteria for sensor positioning are often not declared and not related to location accuracy. In the present paper, a tool for the identification of the optimal sensor position on a cubic shape rock specimen is presented. The optimal receiver configuration is chosen by studying the condition numbers of each of the kernel matrices, used for inverting the arrival time and finding the source location, and obtained for properly selected combinations between sensors and sources positions.

  4. On-line sample preconcentration by sweeping and poly(ethylene oxide)-mediated stacking for simultaneous analysis of nine pairs of amino acid enantiomers in capillary electrophoresis.

    PubMed

    Lin, En-Ping; Lin, Kai-Cheng; Chang, Chia-Wei; Hsieh, Ming-Mu

    2013-09-30

    This study proposes a sensitive method for the simultaneous separation and concentration of 9 pairs of amino acid enantiomers by combining poly(ethylene oxide) (PEO)-based stacking, β-cyclodextrin (β-CD)-mediated micellar electrokinetic chromatography (MEKC), and 9-fluoroenylmethyl chloroformate (FMOC) derivatization. The 9 pairs of FMOC-derivatized amino acid enantiomers were baseline separated using a discontinuous system, and the buffer vials contained a solution of 150 mM Tris-borate (TB), 12.5% (v/v) isopropanol (IPA), 0.5% (w/v) PEO, 35 mM sodium taurodeoxycholate (STDC), and 35 mM β-CD, and the capillary was filled with a solution of 1.5 M TB, 12.5% (v/v) IPA, 35 mM STDC, and 35 mM β-CD. Based on the difference in viscosity between the sample zone and PEO solution and because of the STDC sweeping, the discontinuous system effectively stacked 670 nL of the 9 pairs of FMOC-derivatized amino acid enantiomers without losing chiral resolution. Consequently, the limits of detection for the 9 pairs of FMOC-derivatized amino acid enantiomers were reduced to 40-60 nM. This method was successfully used to determine d-Tryptophan (Trp), l-Trp, d-Phenylalanine (Phe), l-Phe, d-Glutamic acid (Glu), and l-Glu in various types of beers.

  5. Fast and sensitive method to determine parabens by capillary electrophoresis using automatic reverse electrode polarity stacking mode: application to hair samples.

    PubMed

    Sako, Alysson V F; Dolzan, Maressa D; Micke, Gustavo Amadeu

    2015-09-01

    This paper describes a fast and sensitive method for the determination of methyl, ethyl, propyl, and butylparaben in hair samples by capillary electrophoresis using automatic reverse electrode polarity stacking mode. In the proposed method, solutions are injected using the flush command of the analysis software (940 mbar) and the polarity switching is carried out automatically immediately after the sample injection. The advantages compared with conventional stacking methods are the increased analytical frequency, repeatability, and inter-day precision. All analyses were performed in a fused silica capillary (50 cm, 41.5 cm in effective length, 50 μm i.d.), and the background electrolyte was composed of 20 mmol L(-1) sodium tetraborate in 10 % of methanol, pH 9.3. For the reverse polarity, -25 kV/35 s was applied followed by application of +30 kV for the electrophoretic run. Temperature was set at 20 °C, and all analytes were monitored at 297 nm. The method showed acceptable linearity (r (2) > 0.997) in the studied range of 0.1-5.0 mg L(-1), limits of detection below 0.017 mg L(-1), and inter-day, intra-day, and instrumental precision better than 6.2, 3.6, and 4.6 %, respectively. Considering parabens is widely used as a preservative in many products and the reported possibility of damage to the hair and also to human health caused by these compounds, the proposed method was applied to evaluate the adsorption of parabens in hair samples. The results indicate that there is a greater adsorption of methylparaben compared to the other parabens tested and also dyed hairs had a greater adsorption capacity for parabens than natural hairs.

  6. Selecting Locations for Medium Intensity Sampling of Soil Organic Carbon in Alaska

    NASA Astrophysics Data System (ADS)

    Bliss, N. B.; Maursetter, J.

    2004-12-01

    A warming climate may lead to the release of the greenhouse gases carbon dioxide and methane from Arctic soils, resulting in a positive feedback. Quantifying soil carbon stocks is necessary for calibrating models of carbon flux. The total stocks of soil carbon in high latitudes are poorly quantified because there are few soil samples. As a guide to additional sampling, such as the new 3rd Tier Medium-Intensity Sampling planned in the North American Carbon Program, we have investigated methods of using existing soil databases to map the intensities and calculate the total quantities of soil carbon in Alaska. We have related the laboratory data on soil physical and chemical properties for specific locations (the pedon data) to the soil components of the digital maps in the State Soil Geographic (STATSGO) database. Both data sources are from the U.S. Department of Agriculture's Natural Resources Conservation Service. We evaluated 523 pedons for Alaska, selected those for which soil organic carbon could be calculated, and investigated several methods of matching them to the digital soil maps. The soil taxonomic classification (usually at the suborder, great group, or subgroup level), slope, and location were used in multiple combinations for linking the detailed profile descriptions to the general soil maps. We illustrate the uncertainty of estimations of carbon stocks by using alternative methods of performing the data selection and matching. Each matching method allows a many-to-many relation between the pedon point observations and the components of the soil maps. Once extrapolated to the map, a large measure of carbon stock attributed to a given sample point indicates an area in which additional sampling would efficiently reduce the uncertainty of the soil organic carbon estimates.

  7. Results of Macroinvertebrate Sampling Conducted at 33 SRS Stream Locations, July--August 1993

    SciTech Connect

    Specht, W.L.

    1994-12-01

    In order to assess the health of the macroinvertebrate communities of SRS streams, the macroinvertebrate communities at 30 stream locations on SRS were sampled during the summer of 1993, using Hester-Dendy multiplate samplers. In addition, three off-site locations in the Upper Three Runs drainage were sampled in order to assess the potential for impact from off-site activities. In interpreting the data, it is important to recognize that these data were from a single set of collections. Macroinvertebrate communities often undergo considerable temporal variation, and are also greatly influenced by such factors as water depth, water velocity, and available habitat. These stations were selected with the intent of developing an on-going sampling program at a smaller number of stations, with the selection of the stations to be based largely upon the results of this preliminary sampling program. When stations within a given stream showed similar results, fewer stations would be sampled in the future. Similarly, if a stream appeared to be perturbed, additional stations or chemical analyses might be added so that the source of the perturbation could be identified. In general, unperturbed streams will contain more taxa than perturbed streams, and the distribution of taxa among orders or families will differ. Some groups of macroinvertebrates, such as Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies), which are collectively called EPT taxa, are considered to be relatively sensitive to most kinds of stream perturbation; therefore a reduced number of EPT taxa generally indicates that the stream has been subject to chemical or physical stressors. In coastal plain streams, EPT taxa are generally less dominant than in streams with rocky substrates, while Chironomidae (midges) are more abundant. (Abstract Truncated)

  8. ENVIRONMENTAL SAMPLING USING LOCATION SPECIFIC AIR MONITORING IN BULK HANDLING FACILITIES

    SciTech Connect

    Sexton, L.; Hanks, D.; Degange, J.; Brant, H.; Hall, G.; Cable-Dunlap, P.; Anderson, B.

    2011-06-07

    Since the introduction of safeguards strengthening measures approved by the International Atomic Energy Agency (IAEA) Board of Governors (1992-1997), international nuclear safeguards inspectors have been able to utilize environmental sampling (ES) (e.g. deposited particulates, air, water, vegetation, sediments, soil and biota) in their safeguarding approaches at bulk uranium/plutonium handling facilities. Enhancements of environmental sampling techniques used by the IAEA in drawing conclusions concerning the absence of undeclared nuclear materials or activities will soon be able to take advantage of a recent step change improvement in the gathering and analysis of air samples at these facilities. Location specific air monitoring feasibility tests have been performed with excellent results in determining attribute and isotopic composition of chemical elements present in an actual test-bed sample. Isotopic analysis of collected particles from an Aerosol Contaminant Extractor (ACE) collection, was performed with the standard bulk sampling protocol used throughout the IAEA network of analytical laboratories (NWAL). The results yielded bulk isotopic values expected for the operations. Advanced designs of air monitoring instruments such as the ACE may be used in gas centrifuge enrichment plants (GCEP) to detect the production of highly enriched uranium (HEU) or enrichments not declared by a State. Researchers at Savannah River National Laboratory in collaboration with Oak Ridge National Laboratory are developing the next generation of ES equipment for air grab and constant samples that could become an important addition to the international nuclear safeguards inspector's toolkit. Location specific air monitoring to be used to establish a baseline environmental signature of a particular facility employed for comparison of consistencies in declared operations will be described in this paper. Implementation of air monitoring will be contrasted against the use of smear ES

  9. 49 CFR 178.606 - Stacking test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Stacking test. 178.606 Section 178.606... Packagings and Packages § 178.606 Stacking test. (a) General. All packaging design types other than bags must be subjected to a stacking test. (b) Number of test samples. Three test samples are required for...

  10. Geophysical methods to support correct water sampling locations for salt dilution gauging

    NASA Astrophysics Data System (ADS)

    Comina, C.; Lasagna, M.; De Luca, D. A.; Sambuelli, L.

    2014-08-01

    To improve water management design, particularly in irrigation areas, it is important to evaluate the baseline state of the water resources, including canal discharge. Salt dilution gauging is a traditional and well-documented technique in this respect. The complete mixing of salt used for dilution gauging is required; this condition is difficult to test or verify and, if not fulfilled, is the largest source of uncertainty in the discharge calculation. In this paper, a geophysical technique (FERT, fast electrical resistivity tomography) is proposed for imaging the distribution of the salt plume used for dilution gauging at every point along a sampling cross section. With this imaging, complete mixing can be verified. If the mixing is not complete, the image created by FERT can also provide a possible guidance for selecting water-sampling locations in the sampling cross section. A water multi-sampling system prototype aimed to potentially take into account concentration variability is also proposed and tested. The results reported in the paper show that FERT provides a three-dimensional image of the dissolved salt plume and that this can potentially help in the selection of water sampling points.

  11. Locating the acoustic source in thin glass plate using low sampling rate data.

    PubMed

    Hoseini Sabzevari, S Amir; Moavenian, Majid

    2016-08-01

    Acoustic source localization is an important step for structural health monitoring (SHM). There are many research studies dealing with localization based on high sampling rate data. In this paper, for the first time, acoustic source is localized on an isotropic plate using low sampling rate data. Previous studies have mainly used a cluster of specific sensors to easily record high sampling rate signals containing qualitative time domain features. This paper proposes a novel technique to localize the acoustic source on isotropic plates by simply implementing a combination of two simple electret microphones and Loci of k-Tuple Distances (LkTD) from the two sensors with low sampling rate data. In fact the method proposes substitution of previous methods based on solving the system of equations and increasing the number of sensors by implementing the selection of LkTD. Unlike most previous studies, estimation of time difference of arrival (TDOA) is based on the frequency properties of the signal rather than it's time properties. An experimental set-up is prepared and experiments are conducted to validate the proposed technique by prediction of the acoustic source location. The experimental results show that TDOA estimations based on low sampling rate data can produce more accurate predictions in comparison with previous studies. It is also shown that the selection of LkTD on the plate has noticeable effects on the performance of this technique. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Sampling and composition of airborne particulate matter (PM10) from two locations of Mexico City.

    PubMed

    Chirino, Yolanda I; Sánchez-Pérez, Yesennia; Osornio-Vargas, Álvaro Román; Rosas, Irma; García-Cuellar, Claudia María

    2015-09-01

    The PM10 airborne particulate matter with an aerodynamic diameter ≤10 µm is considered as a risk factor of various adverse health outcomes, including lung cancer. Here we described the sampling and composition of PM10 collected from an industrial zone (IZ), and a commercial zone (CZ) of Mexico City. The PM10 was collected with a high-volume sampler in the above mentioned locations and both types of PM10 sampled were characterized by the content of polycyclic aromatic hydrocarbons (PAHs), metals, and endotoxin. The endotoxin PM10 content from IZ and CZ displayed 138.4 UE/mg and 170.4 UE/mg of PM10, respectively.

  13. Determination of nerve agent degradation products by capillary electrophoresis using field-amplified sample stacking injection with the electroosmotic flow pump and contactless conductivity detection.

    PubMed

    Xu, Li; Hauser, Peter C; Lee, Hian Kee

    2009-07-31

    In the present study, field-amplified sample stacking injection using the electroosmotic flow pump (FAEP) was developed for the capillary electrophoretic separation of the four nerve agent degradation products methylphosphonic acid (MPA), ethyl methylphosphonic acid (EMPA), isopropyl methylphosphonic acid (IMPA) and cyclohexyl methylphosphonic acid (CMPA). Coupled to contactless conductivity detection, direct quantification of these non-UV active compounds could be achieved. Sensitivity enhancement of up to 500 to 750-fold could be obtained. The newly established approach was applied to the determination of the analytes in river water and aqueous extracts of soil. Detection limits of 0.5, 0.7, 1.4 and 2.7 ng/mL were obtained for MPA, EMPA, IMPA and CMPA, respectively, in river water and 0.09, 0.14, 0.44 and 0.22 microg/g, respectively, in soil.

  14. Identification of clusters of foot pain location in a community sample.

    PubMed

    Gill, Tiffany K; Menz, Hylton B; Landorf, Karl B; Arnold, John B; Taylor, Anne W; Hill, Catherine L

    2017-02-23

    To identify foot pain clusters according to pain location in a community based sample of the general population. This study analysed data from the North West Adelaide Health Study. Data were obtained between 2004-2006, using Computer Assisted Telephone Interviewing, clinical assessment and self-completed questionnaire. The location of foot pain was assessed using a diagram during the clinical assessment. Hierarchical cluster analysis was undertaken to identify foot pain location clusters, which were then compared in relation to demographics, comorbidities and podiatry utilisation. There were 558 participants with foot pain (mean age 54.4 years, 57.5% female). Five clusters were identified: one with predominantly arch and ball pain (26.8%); one with hindfoot pain (20.9%); another with heel pain (13.3%), and two with predominantly forefoot, toe and nail pain (28.3% and 10.7%). Each cluster was distinct in age, sex and comorbidity profiles. Of the two clusters with predominantly forefoot, toe and nail pain, one had a higher proportion of males, and those who were classified as obese, had diabetes and who used podiatry services (30%), while the other was comprised of a higher proportion of females who were overweight and had a lower use of podiatry services (17.5%). Five clusters of foot pain according to pain location were identified, all with distinct age, sex and comorbidity profiles. These findings may assist in identifying individuals at risk for developing foot pain and the development of targeted preventative strategies and treatments. This article is protected by copyright. All rights reserved. © 2017, American College of Rheumatology.

  15. Gas dispersion concentration of trace inorganic contaminants from fuel gas and analysis using head-column field-amplified sample stacking capillary electrophoresis.

    PubMed

    Yang, Jianmin; Li, Hai-Fang; Li, Meilan; Lin, Jin-Ming

    2012-08-21

    The presence of inorganic elements in fuel gas generally accelerates the corrosion and depletion of materials used in the fuel gas industry, and even leads to serious accidents. For identification of existing trace inorganic contaminants in fuel gas in a portable way, a highly efficient gas-liquid sampling collection system based on gas dispersion concentration is introduced in this work. Using the constructed dual path gas-liquid collection setup, inorganic cations and anions were simultaneously collected from real liquefied petroleum gas (LPG) and analyzed by capillary electrophoresis (CE) with indirect UV absorbance detection. The head-column field-amplified sample stacking technique was applied to improve the detection limits to 2-25 ng mL(-1). The developed collection and analytical methods have successfully determined existing inorganic contaminants in a real LPG sample in the range of 4.59-138.69 μg m(-3). The recoveries of cations and anions with spiked LPG samples were between 83.98 and 105.63%, and the relative standard deviations (RSDs) were less than 7.19%.

  16. Ultra-sensitive speciation analysis of mercury by CE-ICP-MS together with field-amplified sample stacking injection and dispersive solid-phase extraction.

    PubMed

    Chen, YiQuan; Cheng, Xian; Mo, Fan; Huang, LiMei; Wu, Zujian; Wu, Yongning; Xu, LiangJun; Fu, FengFu

    2016-04-01

    A simple dispersive solid-phase extraction (DSPE) used to extract and preconcentrate ultra-trace MeHg, EtHg and Hg(2+) from water sample, and a sensitive method for the simultaneous analysis of MeHg, EtHg and Hg(2+) by using capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS) with field-amplified sample stacking injection (FASI) were first reported in this study. The DSPE used thiol cotton particles as adsorbent, and is simple and effective. It can be used to extract and preconcentrate ultra-trace mercury compounds in water samples within 30 min with a satisfied recovery and no mercury species alteration during the process. The FASI enhanced the sensitivity of CE-ICP-MS with 25-fold, 29-fold and 27-fold for MeHg, EtHg and Hg(2+) , respectively. Using FASI-CE-ICP-MS together with DSPE, we have successfully determined ultra-trace MeHg, EtHg and Hg(2+) in tap water with a limits of quantification (LOQs) of 0.26-0.45 pg/mL, an RSD (n = 3) < 6% and a recovery of 92-108%. Ultra-high sensitivity, as well as much less sample and reagent consumption and low operating cost, make our method a valuable technique to the speciation analysis of ultra-trace mercury.

  17. An online field-amplification sample stacking method for the determination of diuretics in urine by capillary electrophoresis-amperometric detection.

    PubMed

    Zheng, Xinyu; Lu, Minghua; Zhang, Lan; Chi, Yuwu; Zheng, Lihui; Chen, Guonan

    2008-06-30

    A simple and sensitive online field-amplification sample stacking (FASS) pre-enrichment method following by capillary electrophoresis with amperometric detection has been developed for the determination of diuretics, such as indapamide (IDP), hydrochlorothiazide (HCT) and bumetanide (BMTN) in urine. Under the optimum conditions, it was found that the low concentration buffer solution could be used as the diluents for simultaneous field-amplification injection of three diuretics after electrokinetically injecting a short water plug (15 kV, 3 s). Three analytes could be well separated within 10 min in an uncoated fused-silica capillary with H(3)BO(3)-Na(2)B(4)O(7) (BB) buffer solution (pH 8.98). The detection limits (S/N=3) were 9.0 ng/mL for IDP, 20 ng/mL for HCT and 1.5 ng/mL for BMTN, respectively. The detection limits of three diuretics were much lower by FASS than that by conventional sample injection, of which the detection limits were 340, 890 and 330 ng/mL for IDP, HCT and BMTN, respectively. Especially, for bumetanide the detection limit was 220-time lower by FASS. The linear ranges of three diuretics were all over three orders of magnitude. The proposed method has been successfully applied to analyze the diuretics in human urine samples without off-column sample pre-concentration.

  18. Sample stacking microemulsion electrokinetic capillary chromatography induced by reverse migrating pseudostationary phase for the quantification of phenobarbital and its p-hydroxyphenobarbital metabolite in rat urine.

    PubMed

    Kadi, Adnan; Hefnawy, Mohamed; Julkhuf, Saeed; Abounassif, Mohammed; Mostafa, Gamal; Kassem, Mohamed G; Attia, Sabry; Al-Ghamdi, Ali

    2011-07-07

    For the first time, a capillary electrophoretic (CE) method with sample stacking induced by a reverse migrating pseudostationary phase (SRMP) technique has been developed and validated for sensitive determination of phenobarbital (PB) and its p-hydroxyphenobarbital (PHPB) metabolite in rat urine samples. Separation and determination were optimized on a fused-silica capillary with a total length of 50 cm (effective length 40 cm) and 75 μm ID. The microemulsion background electrolyte consisted of 0.8% (v/v) ethyl acetate, 6.6% (v/v) butan-2-ol, 1.0% (v/v) acetonitrile, 2.0% (w/v) sodium n-dodecyl sulfate (SDS), and 89.6% (v/v) of 7.5 mM ammonium formate at pH 8. When this preconcentration technique was used, the sample stacking and the separation processes took place successively with changing the voltage with an intermediate polarity switching step. For practical application, a solid-phase extraction (SPE), C(18) sorbent with n-hexane/ethyl acetate (1 : 1%, v/v) as the elution solvent was used for sample purification and concentration. The SPE method gave good extraction yields for all the analytes, with absolute recovery values of 96.9% and 99.1% for PB and PHPB, respectively. The regression equations for PB and PHPB showed excellent linearity over a concentration range of 55-1386 ng mL(-1) for PB and PHPB (r = 0.998). The developed microemulsion electrokinetic capillary chromatography (MEEKC) method for separation of the studied compounds with SRMP as the electrophoretic preconcentration technique allowed detection limits in urine samples at 16.8 ng mL(-1) for PB and PHPB which are 15-fold lower than the reported CE method in the literature. The precision results, expressed by the intra-day and inter-day relative standard deviation (RSD) values range from 3.6 to 7.1% (repeatability) and from 3.2 to 7.2% (intermediate precision) for PB and PHPB, respectively, which were in line with Food and Drug Administration (FDA) criteria.

  19. Large volume sample stacking for rapid and sensitive determination of antidiabetic drug metformin in human urine and serum by capillary electrophoresis with contactless conductivity detection.

    PubMed

    Tůma, Petr

    2014-06-06

    Two CE methods with contactless conductivity detection have been developed for determining the oral antidiabetic drug metformin in human urine and blood. The determination of metformin is performed on a separation capillary with an effective length of 14 cm, using a maximum voltage of 30 kV and with a small injection of 50-fold diluted urine into the capillary. Under these conditions, the migration time of metformin is 35s and the LOD is 0.3 μM. Large-volume sample stacking was used to determine low metformin levels in serum. The injection of a sample of serum deproteinized with acetonitrile was 10 times greater compared to the injected amount of urine. This enabled reduction of the LOD to 0.03 μM and the metformin migration time equalled 86 s. The undesirable solvent from sample zone was forced out of the capillary to ensure rapidity and good repeatability of the determination. The RSD values for the migration time are 0.1% for urine and 0.7% for serum; RSD for the peak areas equalled 1.4% for urine and 2.6% for serum. The developed CE technique was tested on performance of routine analyses of metformin in the urine and serum of patients suffering from type II diabetes mellitus. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. The effects of sampling location and turbulence on discharge estimates in short converging turbine intakes

    SciTech Connect

    Romero-Gomez, P.; Harding, S. F.; Richmond, M. C.

    2017-01-01

    Standards provide recommendations for best practices when installing current meters to measure fluid flow in closed conduits. A central guideline requires the velocity distribution to be regular and the flow steady. Because of the nature of the short converging intakes typical of low-head hydroturbines, these assumptions may be invalid if current meters are intended to be used to estimate discharge. Usual concerns are (1) the effects of the number of devices, (2) the sampling location and (3) the high turbulence caused by blockage from submersible traveling screens usually deployed for safe downstream fish passage. These three effects were examined in the present study by using 3D simulated flow fields in both steady-state and transient modes. In the process of describing an application at an existing hydroturbine intake at Ice Harbor Dam, the present work outlined the methods involved, which combined computational fluid dynamics, laboratory measurements in physical models of the hydroturbine, and current meter performance evaluations in experimental settings. The main conclusions in this specific application were that a steady-state flow field sufficed to determine the adequate number of meters and their location, and that both the transverse velocity and turbulence intensity had a small impact on estimate errors. However, while it may not be possible to extrapolate these findings to other field conditions and measuring devices, the study laid out a path to conduct similar assessments in other applications.

  1. Comparison of media and sampling locations for isolation of Listeria monocytogenes in queso fresco cheese.

    PubMed

    Lin, Chia-Min; Zhang, Lei; Doyle, Michael P; Swaminathan, Bala

    2006-09-01

    Listeriosis associated with Hispanic-style soft cheese is an ongoing public health concern. Although rapid detection methods based on molecular and immunological technologies have been applied successfully for detecting Listeria monocytogenes in foods, obtaining isolates of the pathogen is a critical procedure for epidemiologic studies and regulatory analysis. Oxford agar, a medium recommended by the U.S. Food and Drug Administration Bacteriological Analytical Manual (BAM) to isolate L. monocytogenes from cheese, is unable to differentiate L. monocytogenes from other Listeria species. Hence, two selective isolation media, L. monocytogenes blood agar (LMBA) and Rapid 'L. mono agar (RLMA), were compared with Oxford agar for isolating L. monocytogenes from cheese. Queso fresco cheese was inoculated at 10(0) or 10(1) CFU/g with a five-strain mixture of L. monocytogenes or with the five-strain L. monocytogenes mixture and Listeria innocua. Cheese samples were stored at 21, 12, and 4 degrees C and Listeria counts were determined at 3, 7, and 10 days; 7, 10, 14, 21 days; and 2, 4, 8, and 12 weeks postinoculation, respectively. Surface and interior cheese samples as well as liquid exudate produced during storage were assayed individually to determine differences in Listeria contamination at different sampling locations. L. monocytogenes was more easily differentiated from L. innocua on RLMA than LMBA and Oxford agar. Similar L. monocytogenes counts (ca. 10(4) CFU/g) were obtained on the last sampling day on the surface and interior of cheese samples (P > 0.05) for all storage temperatures and both initial inoculation levels, but smaller cell numbers were detected in the exudate produced during storage. In addition, simultaneous inoculation of L. innocua with L. monocytogenes did not affect the final L. monocytogenes counts in the cheese. The amount of exudate released from the cheese and decrease of pH correlated with storage temperature. More exudate was produced and a

  2. Analysis of Six β-Lactam Residues in Milk and Egg by Micellar Electrokinetic Chromatography with Large-Volume Sample Stacking and Polarity Switching.

    PubMed

    Shao, Yu-Xiu; Chen, Guan-Hua; Fang, Rou; Zhang, Li; Yi, Ling-Xiao; Meng, Hong-Lian

    2016-05-04

    A new micellar electrokinetic chromatography method with large-volume sample stacking and polarity switching was developed to analyze amoxicllin, cephalexin, oxacillin, penicillin G, cefazolin, and cefoperazone in milk and egg. The important parameters influencing separation and enrichment factors were optimized. The optimized running buffer consisted of 10 mM phosphate and 22 mM SDS at pH 6.7. The sample size was 1.47 kPa × 690 s, the reverse voltage was 20 kV, and the electric current recovery was 95%. Under these optimum conditions, the enrichment factors of six β-lactams were 193-601. Their LODs were <0.26 ng/g, and LOQs were all 2 ng/g, which was only 1/50-1/2 of the maximum residual limits demanded by U.S. and Japanese regulations. The intraday and interday RSDs of method were lower than 3.70 and 3.91%, respectively. The method can be applied to determine these six antibiotic residues in egg and milk.

  3. Assay for the determination of low dosage form of formoterol dry syrup by capillary electrophoresis with head-column field-amplified sample stacking.

    PubMed

    Song, J Z; Chen, J; Tian, S J; Sun, Z P

    1999-11-01

    The development of a capillary zone electrophoresis method with head-column field-amplified sample stacking injection for the determination of formoterol (FMTR) in a low dosage dry syrup form was described. To obtain the highest sensitivity, the sample solution was prepared by high content of organic solvent with the presence of a small amount of H+ (60-100 microM) and the capillary inlet end was dipped in water before electroinjection. This method was fully validated in terms of repeatability (RSDs for migration time, peak area of FMTR and peak area ratio between FMTR and I.S. at 1 microg/ml of FMTR was 0.76, 1.10 and 0.55% respectively), reproducibility (RSDs from different capillaries, analytes, days and instruments were 1.52%, 1.04%, 1.16% and 1.93% respectively), linearity (y = 0.827x - 0.085, r = 0.9993 (n = 6) over the range of 0.25-2.0 microg/ml), limits of quantitation, ruggedness and robustness. The method was applied to the determination of the drug in commercial dry syrup preparation (recovery was 100.9%, RSD = 1.5%, n = 5) and proved to be fast and reliable for the quantitation analysis of FMTR in the pharmaceutical form.

  4. Gamma-ray Excess from a Stacked Sample of High- and Intermediate-frequency Peaked Blazars Observed with the MAGIC Telescope

    NASA Astrophysics Data System (ADS)

    Aleksić, J.; Antonelli, L. A.; Antoranz, P.; Backes, M.; Baixeras, C.; Barrio, J. A.; Bastieri, D.; Becerra González, J.; Bednarek, W.; Berdyugin, A.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Bonnoli, G.; Bordas, P.; Borla Tridon, D.; Bosch-Ramon, V.; Bose, D.; Braun, I.; Bretz, T.; Britzger, D.; Camara, M.; Carmona, E.; Carosi, A.; Colin, P.; Commichau, S.; Contreras, J. L.; Cortina, J.; Costado, M. T.; Covino, S.; Dazzi, F.; De Angelis, A.; De Cea del Pozo, E.; De los Reyes, R.; De Lotto, B.; De Maria, M.; De Sabata, F.; Delgado Mendez, C.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Elsaesser, D.; Errando, M.; Ferenc, D.; Fonseca, M. V.; Font, L.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Godinovic, N.; Hadasch, D.; Herrero, A.; Hildebrand, D.; Höhne-Mönch, D.; Hose, J.; Hrupec, D.; Hsu, C. C.; Jogler, T.; Klepser, S.; Krähenbühl, T.; Kranich, D.; La Barbera, A.; Laille, A.; Leonardo, E.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Lorenz, E.; Majumdar, P.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Miyamoto, H.; Moldón, J.; Moles, M.; Moralejo, A.; Nieto, D.; Nilsson, K.; Ninkovic, J.; Orito, R.; Oya, I.; Paiano, S.; Paoletti, R.; Paredes, J. M.; Partini, S.; Pasanen, M.; Pascoli, D.; Pauss, F.; Pegna, R. G.; Perez-Torres, M. A.; Persic, M.; Peruzzo, L.; Prada, F.; Prandini, E.; Puchades, N.; Puljak, I.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Rissi, M.; Rügamer, S.; Saggion, A.; Saito, T. Y.; Salvati, M.; Sánchez-Conde, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shayduk, M.; Shore, S. N.; Sierpowska-Bartosik, A.; Sillanpää, A.; Sitarek, J.; Sobczynska, D.; Spanier, F.; Spiro, S.; Stamerra, A.; Steinke, B.; Struebig, J. C.; Suric, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzic, T.; Tescaro, D.; Teshima, M.; Tibolla, O.; Torres, D. F.; Vankov, H.; Wagner, R. M.; Weitzel, Q.; Zabalza, V.; Zandanel, F.; Zanin, R.

    2011-03-01

    Between 2004 and 2009, a sample of 28 X-ray selected high- and intermediate-frequency peaked blazars with an X-ray flux larger than 2 μJy at 1 keV in the redshift range from 0.018 to 0.361 was observed with the MAGIC telescope at energies above 100 GeV. Seven among them were detected and the results of these observations are discussed elsewhere. Here we concentrate on the remaining 21 blazars which were not detected during this observation campaign and present the 3σ (99.7%) confidence upper limits on their flux. The individual flux upper limits lie between 1.6% and 13.6% of the integral flux from the Crab Nebula. Applying a stacking method to the sample of non-detections with a total of 394.1 hr exposure time, we find evidence for an excess with a cumulative significance of 4.9 standard deviations. It is not dominated by individual objects or flares, but increases linearly with the observation time as for a constant source with an integral flux level of ~1.5% of that observed from the Crab Nebula above 150 GeV.

  5. Large volume sample stacking with EOF and sweeping in CE for determination of common preservatives in cosmetic products by chemometric experimental design.

    PubMed

    Cheng, Yi-Cian; Wang, Chun-Chi; Chen, Yen-Ling; Wu, Shou-Mei

    2012-05-01

    This study proposes a capillary electrophoresis method incorporating large volume sample stacking, EOF and sweeping for detection of common preservatives used in cosmetic products. The method was developed using chemometric experimental design (fractional factorial design and central composite design) to determine multiple separation variables by efficient steps. The samples were loaded by hydrodynamic injection (10 psi, 90 s), and separated by phosphate buffer (50 mM, pH 3) containing 30% methanol and 80 mM SDS at -20 kV. During method validation, calibration curves were found to be linear over a range of 5-100 μg/mL for butyl paraben and isobutyl paraben; 0.05-10 μg/mL for ethyl paraben; 0.2-50 μg/mL for dehydroacetic acid; 0.5-70 μg/mL for methyl paraben; 5-350 μg/mL for sorbic acid; 0.02-450 μg/mL for p-hydroxybenzoic acid and 0.05-10 μg/mL for salicylic acid and benzoic acid. The analytes were analysed simultaneously and their detection limits (S/N = 3) were down to 0.005-2 μg/mL. The analysis method was successfully used for detection of preservatives used in commercial cosmetics.

  6. On-line capillary electrophoresis enrichment by combining chitosan trapping with surfactant assisted sample stacking for the ultratrace determination of organic acids in Plateau alfalfa roots.

    PubMed

    Li, Xi; Ju, Yuyun; Xu, Yinyin; Wang, Weifeng; Dong, Yalei; Ma, Yanhua; Chen, Xingguo

    2013-07-30

    In this paper, four organic acids constituents of Plateau alfalfa roots have been identified and detected by a novel capillary electrophoresis (CE) strategy which combined chitosan (CS) trapping and cetyltrimethyl ammonium bromide (CTAB) assisted sample stacking. Under the optimized condition, organic acids, i.e., aconitic acid, gallic acid, citric acid and l-malic acid were concentrated and separated within 3 min. Validation parameters of this method (such as detection limits, linearity and precision) were also investigated and the limit of detection (LOD) was 2.41-53.9 ng mL(-1). Linearity was obtained over the magnitude range of 5-4000 ng mL(-1) approximately for different organic acids and 3×10(2)-1.5×10(4) folds enrichment was achieved. The method has been applied to the determination of organic acids in roots of normal grown Plateau alfalfa and stressing affected Plateau alfalfa. Satisfactory results and recoveries were obtained in the analysis without costly and complicated sample pretreatment.

  7. Application of fractionized sampling and stacking for construction of an interface for online heart-cutting two-dimensional liquid chromatography.

    PubMed

    Ji, Baocheng; Xia, Bing; Liu, Jie; Gao, Yuanji; Ding, Lisheng; Zhou, Yan

    2016-09-30

    In this study, an efficient interface, based on a fractionized sampling and stacking (FSS) strategy, was developed for online heart-cutting two-dimensional liquid chromatography (2D LC). This interface consisted of a two-position 4-port valve, a two-position 6-port valve and a two-position 10-port valve equipped with two 450-μL stainless steel loops. Hydrophilic interaction chromatography (HILIC) and reversed phase liquid chromatography (RP LC) were used in the first and second dimensions, respectively. The peak compression efficiency of this interface was investigated by analysis of ten standards. Good peak shapes of the ten standards were observed when the dilution ratio was over five and the co-eluate plug volume was less than 10μL. The 2D LC system was further applied to analysis of a crude extract of Panax ginseng leaves. Seventeen major constituents in the extract were monitored, which could not be well separated by one-dimensional (1D) HILIC or RP LC method in a long separation gradient. The FSS interface successfully achieved the efficient combination of HILIC and RP LC, and the 17 constituents in ginseng extract got well separated under the optimized conditions. The FSS interface has shown great potential for 2D LC analysis of complex natural product samples.

  8. Use of Loran-C navigation system to accurately determine sampling site location in an above ground cooling reservoir

    SciTech Connect

    Lockwood, R.E.; Blankinship, D.R.

    1994-12-31

    Environmental monitoring programs often require accurate determination of sampling site locations in aquatic environments. This is especially true when a {open_quotes}picture{close_quotes} of high resolution is needed for observing a changing variable in a given area and location is assumed to be important to the distribution of that variable. Sample site location can be difficult if few visible land marks are available for reference on a large body of water. The use of navigational systems such as Global Positioning System (GPS) and its predecessor, Loran-C, provide an excellent method for sample site location. McFarland (1992) discusses the practicality of GPS for location determination. This article discusses the use of Loran-C in a sampling scheme implemented at the South Texas Project Electrical Generating Station (STPEGS), Wadsworth, Texas.

  9. Coupling of acetonitrile deproteinization and salting-out extraction with acetonitrile stacking for biological sample clean-up and the enrichment of hydrophobic compounds (porphyrins) in capillary electrophoresis.

    PubMed

    Li, Qi; Huie, Carmen W

    2006-11-01

    A new sample pretreatment approach in CE was developed for concurrent biological sample clean-up and the concentration of hydrophobic compounds based on the combination of ACN deproteinization with salting-out extraction. Further enhancement in concentration detection sensitivity was achieved by coupling (offline) salting-out extraction with an online CE sample enrichment technique known as "ACN stacking". By optimizing the pH of salting-out extraction, a number of model compounds (hydrophobic porphyrins with clinical significances), i.e. zinc-protoporphyrin, protoporphyrin, and coproporphyrin (CP) III and I, can be efficiently extracted from the aqueous sample into a smaller volume organic solvent (ACN) phase and an enrichment factor of ca. 100 can be obtained. The pressure injection of the enriched ACN phase (containing ca.1% NaCl) into the CE capillary at 10% capillary volume resulted in additional concentration of the various hydrophobic porphyrins, allowing for a combined enrichment factor of ca.1000 to be obtained. Calibration curves obtained for the determination of a pair of positional isomers with significant diagnostic value, urinary CPIII and CPI, were found to be linear between 10-300 ng/mL (with R2 = 0.999), and LODs (absorbance detection at 400 nm) were ca. 0.8 ng/mL (1.1 nmol/L of CPIII or CPI). Based on a single salting-out extraction, intraday precisions (nine consecutive injections) for both CPIII and CPI (at spiked concentrations of 10-300 ng/mL into urine) in terms of migration time and peak area were found to be within the range of 0.2-0.5 and 0.8-2.9%, respectively.

  10. Field-amplified sample stacking for the detection of chemical warfare agent degradation products in low-conductivity matrices by capillary electrophoresis-mass spectrometry.

    PubMed

    Lagarrigue, Mélanie; Bossée, Anne; Bégos, Arlette; Delaunay, Nathalie; Varenne, Anne; Gareil, Pierre; Bellier, Bruno

    2008-01-18

    Preconcentration of chemical warfare agent degradation products (alkylphosphonic acids and alkyl alkylphosphonic acids) in low-conductivity matrices (purified water, tap water and local river water) by field-amplified sample stacking (FASS) was developed for capillary electrophoresis (CE) coupled to ion trap mass spectrometry. FASS was performed by adding a mixture of HCOONH(4) and NH(4)OH in appropriate concentrations to the sample. This allowed to control the conductivity and the pH of the sample in order to obtain FASS performances that are independent of analyte concentration. The influence of different parameters on FASS (sample to background electrolyte (BGE) conductivity ratio, injection volume and concentration of BGE) was studied to determine the optimal conditions and was rationalized by using the theoretical model developed by Burgi and Chien. A good correlation was obtained between the bulk electroosmotic velocity predicted by this model and the experimental value deduced from the migration time of the electroosmotic flow marker detected by mass spectrometry (MS). This newly developed method was successfully applied to the analysis of tap water and local river water fortified with the analytes and provided a 10-fold sensitivity enhancement in comparison to the signal obtained without preconcentration procedure. The quite satisfactory repeatability and linearity for peak areas obtained in the 0.5-5 microg mL(-1) concentration range allow quantitative analysis to be implemented. Limits of detection of 0.25-0.5 microg mL(-1) for the alkyl alkylphosphonic acids and of 0.35-5 microg mL(-1) for the alkylphosphonic acids were reached in tap water and river water.

  11. CFD modelling of sampling locations for early detection of spontaneous combustion in long-wall gob areas.

    PubMed

    Yuan, Liming; Smith, Alex C

    In this study, computational fluid dynamics (CFD) modeling was conducted to optimize gas sampling locations for the early detection of spontaneous heating in longwall gob areas. Initial simulations were carried out to predict carbon monoxide (CO) concentrations at various regulators in the gob using a bleeder ventilation system. Measured CO concentration values at these regulators were then used to calibrate the CFD model. The calibrated CFD model was used to simulate CO concentrations at eight sampling locations in the gob using a bleederless ventilation system to determine the optimal sampling locations for early detection of spontaneous combustion.

  12. CFD modelling of sampling locations for early detection of spontaneous combustion in long-wall gob areas

    PubMed Central

    Smith, Alex C.

    2015-01-01

    In this study, computational fluid dynamics (CFD) modeling was conducted to optimize gas sampling locations for the early detection of spontaneous heating in longwall gob areas. Initial simulations were carried out to predict carbon monoxide (CO) concentrations at various regulators in the gob using a bleeder ventilation system. Measured CO concentration values at these regulators were then used to calibrate the CFD model. The calibrated CFD model was used to simulate CO concentrations at eight sampling locations in the gob using a bleederless ventilation system to determine the optimal sampling locations for early detection of spontaneous combustion. PMID:26213572

  13. Development of a New Microextraction Fiber Combined to On-Line Sample Stacking Capillary Electrophoresis UV Detection for Acidic Drugs Determination in Real Water Samples

    PubMed Central

    Araujo, Lilia; Prieto, Avismelsi; Navalón, Alberto; Vílchez, José Luis; Valera, Paola; Zambrano, Ana; Dugas, Vincent

    2017-01-01

    A new analytical method coupling a (off-line) solid-phase microextraction with an on-line capillary electrophoresis (CE) sample enrichment technique was developed for the analysis of ketoprofen, naproxen and clofibric acid from water samples, which are known as contaminants of emerging concern in aquatic environments. New solid-phase microextraction fibers based on physical coupling of chromatographic supports onto epoxy glue coated needle were studied for the off-line preconcentration of these micropollutants. Identification and quantification of such acidic drugs were done by capillary zone electrophoresis (CZE) using ultraviolet diode array detection (DAD). Further enhancement of concentration sensitivity detection was achieved by on-line CE “acetonitrile stacking” preconcentration technique. Among the eight chromatographic supports investigated, Porapak Q sorbent showed higher extraction and preconcentration capacities. The screening of parameters that influence the microextraction process was carried out using a two-level fractional factorial. Optimization of the most relevant parameters was then done through a surface response three-factor Box-Behnken design. The limits of detection and limits of quantification for the three drugs ranged between 0.96 and 1.27 µg∙L−1 and 2.91 and 3.86 µg∙L−1, respectively. Recovery yields of approximately 95 to 104% were measured. The developed method is simple, precise, accurate, and allows quantification of residues of these micropollutants in Genil River water samples using inexpensive fibers. PMID:28686186

  14. Online sample concentration and analysis of drugs of abuse in human urine by micelle to solvent stacking in capillary zone electrophoresis.

    PubMed

    Aturki, Zeineb; Fanali, Salvatore; Rocco, Anna

    2016-10-01

    A sensitive and rapid CZE-UV method was developed to determine drugs and their metabolites' presence in human urine. Ten drugs of abuse were analyzed including four amphetamines, cocaine, cocaethylene, heroin, morphine, 6-monoacetylmorphine, and 4-methylmethcathinone. An MSS (micelle to solvent stacking) approach was evaluated to enhance method sensitivity. This method considers composition of the micellar sample solution matrix and the injection time. Several analytical conditions influencing the resolution of the drugs mixture as pH and buffer concentration, organic solvent content, were also investigated. The base-line separation of all studied analytes in the same run was achieved within 18 min in an uncoated fused silica capillary (50 μm id × 60 cm) using a background solution containing 50 mM phosphate buffer pH 2.5 and 30% ACN v/v. Other experimental parameters such as applied voltage and capillary temperature were set up at 20 kV and 20°C, respectively. LOD values ranging between 15 and 75 ng/mL for all studied compounds were obtained. From a comparison with conventional CZE, the proposed method provides an increase of sensitivity (39- to 55-fold enhancement factor). Under optimal MSS-CZE conditions, good linearity was achieved (R(2) ≤ 0.9998). The method was finally applied to the analysis of urine samples spiked with a standard mixture after a sample pretreatment, reaching satisfactory recovery values. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. 40 CFR 761.283 - Determination of the number of samples to collect and sample collection locations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... established in paragraph (b)(1)(i) of this section by moving the origin one meter in the direction of magnetic north and one meter in the direction east of magnetic north. (2) Mark out a series of sampling points 1.5 meters apart oriented to the grid axes. The sampling points shall proceed in every direction...

  16. 40 CFR 761.283 - Determination of the number of samples to collect and sample collection locations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... established in paragraph (b)(1)(i) of this section by moving the origin one meter in the direction of magnetic north and one meter in the direction east of magnetic north. (2) Mark out a series of sampling points 1.5 meters apart oriented to the grid axes. The sampling points shall proceed in every direction...

  17. 40 CFR 761.283 - Determination of the number of samples to collect and sample collection locations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... established in paragraph (b)(1)(i) of this section by moving the origin one meter in the direction of magnetic north and one meter in the direction east of magnetic north. (2) Mark out a series of sampling points 1.5 meters apart oriented to the grid axes. The sampling points shall proceed in every direction...

  18. 40 CFR 761.283 - Determination of the number of samples to collect and sample collection locations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... established in paragraph (b)(1)(i) of this section by moving the origin one meter in the direction of magnetic north and one meter in the direction east of magnetic north. (2) Mark out a series of sampling points 1.5 meters apart oriented to the grid axes. The sampling points shall proceed in every direction...

  19. 40 CFR 761.283 - Determination of the number of samples to collect and sample collection locations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... established in paragraph (b)(1)(i) of this section by moving the origin one meter in the direction of magnetic north and one meter in the direction east of magnetic north. (2) Mark out a series of sampling points 1.5 meters apart oriented to the grid axes. The sampling points shall proceed in every direction...

  20. A Critical Assessment of Bias in Survey Studies Using Location-Based Sampling to Recruit Patrons in Bars

    PubMed Central

    Morrison, Christopher; Lee, Juliet P.; Gruenewald, Paul J.; Marzell, Miesha

    2015-01-01

    Location-based sampling is a method to obtain samples of people within ecological contexts relevant to specific public health outcomes. Random selection increases generalizability, however in some circumstances (such as surveying bar patrons) recruitment conditions increase risks of sample bias. We attempted to recruit representative samples of bars and patrons in six California cities, but low response rates precluded meaningful analysis. A systematic review of 24 similar studies revealed that none addressed the key shortcomings of our study. We recommend steps to improve studies that use location-based sampling: (i) purposively sample places of interest, (ii) utilize recruitment strategies appropriate to the environment, and (iii) provide full information on response rates at all levels of sampling. PMID:26574657

  1. A Critical Assessment of Bias in Survey Studies Using Location-Based Sampling to Recruit Patrons in Bars.

    PubMed

    Morrison, Christopher; Lee, Juliet P; Gruenewald, Paul J; Marzell, Miesha

    2015-01-01

    Location-based sampling is a method to obtain samples of people within ecological contexts relevant to specific public health outcomes. Random selection increases generalizability; however, in some circumstances (such as surveying bar patrons), recruitment conditions increase risks of sample bias. We attempted to recruit representative samples of bars and patrons in six California cities, but low response rates precluded meaningful analysis. A systematic review of 24 similar studies revealed that none addressed the key shortcomings of our study. We recommend steps to improve studies that use location-based sampling: (i) purposively sample places of interest, (ii) use recruitment strategies appropriate to the environment, and (iii) provide full information on response rates at all levels of sampling.

  2. Electrochemical cell stack assembly

    DOEpatents

    Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

    2010-06-22

    Multiple stacks of tubular electrochemical cells having a dense electrolyte disposed between an anode and a cathode preferably deposited as thin films arranged in parallel on stamped conductive interconnect sheets or ferrules. The stack allows one or more electrochemical cell to malfunction without disabling the entire stack. Stack efficiency is enhanced through simplified gas manifolding, gas recycling, reduced operating temperature and improved heat distribution.

  3. Location, Location, Location!

    ERIC Educational Resources Information Center

    Ramsdell, Kristin

    2004-01-01

    Of prime importance in real estate, location is also a key element in the appeal of romances. Popular geographic settings and historical periods sell, unpopular ones do not--not always with a logical explanation, as the author discovered when she conducted a survey on this topic last year. (Why, for example, are the French Revolution and the…

  4. Location, Location, Location!

    ERIC Educational Resources Information Center

    Ramsdell, Kristin

    2004-01-01

    Of prime importance in real estate, location is also a key element in the appeal of romances. Popular geographic settings and historical periods sell, unpopular ones do not--not always with a logical explanation, as the author discovered when she conducted a survey on this topic last year. (Why, for example, are the French Revolution and the…

  5. Nanometer-sized alumina packed microcolumn solid-phase extraction combined with field-amplified sample stacking-capillary electrophoresis for the speciation analysis of inorganic selenium in environmental water samples.

    PubMed

    Duan, Jiankuan; Hu, Bin; He, Man

    2012-10-01

    In this paper, a new method of nanometer-sized alumina packed microcolumn SPE combined with field-amplified sample stacking (FASS)-CE-UV detection was developed for the speciation analysis of inorganic selenium in environmental water samples. Self-synthesized nanometer-sized alumina was packed in a microcolumn as the SPE adsorbent to retain Se(IV) and Se(VI) simultaneously at pH 6 and the retained inorganic selenium was eluted by concentrated ammonia. The eluent was used for FASS-CE-UV analysis after NH₃ evaporation. The factors affecting the preconcentration of both Se(IV) and Se(VI) by SPE and FASS were studied and the optimal CE separation conditions for Se(IV) and Se(VI) were obtained. Under the optimal conditions, the LODs of 57 ng L⁻¹ (Se(IV)) and 71 ng L⁻¹ (Se(VI)) were obtained, respectively. The developed method was validated by the analysis of a certified reference material of GBW(E)080395 environmental water and the determined value was in a good agreement with the certified value. It was also successfully applied to the speciation analysis of inorganic selenium in environmental water samples, including Yangtze River water, spring water, and tap water. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Mother-child concordance for pain location in a pediatric chronic pain sample

    PubMed Central

    Schwartz, Lindsay F.; Seidman, Laura C.; Zeltzer, Lonnie K.; Tsao, Jennie C. I.

    2013-01-01

    Body maps have long been used to assess pain location in adult and pediatric chronic pain patients. Assessing agreement between parent and child reports of pain location using such maps may help establish a unified picture of children’s pain experience. However, few studies have examined the extent of agreement between mothers and children on the location of the child’s pain. Using kappa coefficients and other determinants of the magnitude of kappa we assessed mother-child concordance in pain location using body maps with 21 standardized areas in 41 children with chronic pain (65.9% female, mean age = 14.60) and their mothers. The highest level of agreement was found for the abdominal region; agreement for the head region was moderate and not superior to the other body areas. Approximately half of the body map areas yielded poor to fair mother-child agreement, while the other half yielded moderate or better agreement. There was more agreement between mothers and sons than between mothers and daughters on the total number of body areas considered painful, but there were no effects of pubertal status, race, and ethnicity on agreement. Our results are consistent with previous studies indicating that parent assessments of children’s pain do not necessarily mimic their child’s report. Future research should test additional psychosocial factors that may contribute to parent-child discordance regarding the location of the child’s pain. PMID:26413192

  7. A comparison of temporal and location-based sampling strategies for global positioning system-triggered electronic diaries.

    PubMed

    Törnros, Tobias; Dorn, Helen; Reichert, Markus; Ebner-Priemer, Ulrich; Salize, Hans-Joachim; Tost, Heike; Meyer-Lindenberg, Andreas; Zipf, Alexander

    2016-11-21

    Self-reporting is a well-established approach within the medical and psychological sciences. In order to avoid recall bias, i.e. past events being remembered inaccurately, the reports can be filled out on a smartphone in real-time and in the natural environment. This is often referred to as ambulatory assessment and the reports are usually triggered at regular time intervals. With this sampling scheme, however, rare events (e.g. a visit to a park or recreation area) are likely to be missed. When addressing the correlation between mood and the environment, it may therefore be beneficial to include participant locations within the ambulatory assessment sampling scheme. Based on the geographical coordinates, the database query system then decides if a self-report should be triggered or not. We simulated four different ambulatory assessment sampling schemes based on movement data (coordinates by minute) from 143 voluntary participants tracked for seven consecutive days. Two location-based sampling schemes incorporating the environmental characteristics (land use and population density) at each participant's location were introduced and compared to a time-based sampling scheme triggering a report on the hour as well as to a sampling scheme incorporating physical activity. We show that location-based sampling schemes trigger a report less often, but we obtain more unique trigger positions and a greater spatial spread in comparison to sampling strategies based on time and distance. Additionally, the location-based methods trigger significantly more often at rarely visited types of land use and less often outside the study region where no underlying environmental data are available.

  8. Locations of Sampling Stations for Water Quality Monitoring in Water Distribution Networks.

    PubMed

    Rathi, Shweta; Gupta, Rajesh

    2014-04-01

    Water quality is required to be monitored in the water distribution networks (WDNs) at salient locations to assure the safe quality of water supplied to the consumers. Such monitoring stations (MSs) provide warning against any accidental contaminations. Various objectives like demand coverage, time for detection, volume of water contaminated before detection, extent of contamination, expected population affected prior to detection, detection likelihood and others, have been independently or jointly considered in determining optimal number and location of MSs in WDNs. "Demand coverage" defined as the percentage of network demand monitored by a particular monitoring station is a simple measure to locate MSs. Several methods based on formulation of coverage matrix using pre-specified coverage criteria and optimization have been suggested. Coverage criteria is defined as some minimum percentage of total flow received at the monitoring stations that passed through any upstream node included then as covered node of the monitoring station. Number of monitoring stations increases with the increase in the value of coverage criteria. Thus, the design of monitoring station becomes subjective. A simple methodology is proposed herein which priority wise iteratively selects MSs to achieve targeted demand coverage. The proposed methodology provided the same number and location of MSs for illustrative network as an optimization method did. Further, the proposed method is simple and avoids subjectivity that could arise from the consideration of coverage criteria. The application of methodology is also shown on a WDN of Dharampeth zone (Nagpur city WDN in Maharashtra, India) having 285 nodes and 367 pipes.

  9. Sampling of Riverine or Marine Bacterial Communities in Remote Locations: From Field to Publication.

    PubMed

    Lehmann, Katja

    2016-01-01

    This protocol describes how to sample and preserve microbial water column samples from rivers that can be used for 16S or 18S metabarcoding studies or shotgun sequencing. It further describes how to extract the DNA for sequencing and how to prepare raw Illumina MiSeq amplicon data and analyze it in the R environment.

  10. Impact of sampling area and location on measurement of indicator organisms during beef carcass interventions

    USDA-ARS?s Scientific Manuscript database

    The effect of sponge sample collection site on the recovery of multiple indicator organisms from beef carcass surfaces was evaluated. Two 4,000 cm2 samples were collected from pre-evisceration carcasses (n=248), one from the inside and outside round area (top site) and one from the navel-plate-bris...

  11. Design of sampling locations for river water quality monitoring considering seasonal variation of point and diffuse pollution loads.

    PubMed

    Varekar, Vikas; Karmakar, Subhankar; Jha, Ramakar; Ghosh, N C

    2015-06-01

    The design of a water quality monitoring network (WQMN) is a complicated decision-making process because each sampling involves high installation, operational, and maintenance costs. Therefore, data with the highest information content should be collected. The effect of seasonal variation in point and diffuse pollution loadings on river water quality may have a significant impact on the optimal selection of sampling locations, but this possible effect has never been addressed in the evaluation and design of monitoring networks. The present study proposes a systematic approach for siting an optimal number and location of river water quality sampling stations based on seasonal or monsoonal variations in both point and diffuse pollution loadings. The proposed approach conceptualizes water quality monitoring as a two-stage process; the first stage of which is to consider all potential water quality sampling sites, selected based on the existing guidelines or frameworks, and the locations of both point and diffuse pollution sources. The monitoring at all sampling sites thus identified should be continued for an adequate period of time to account for the effect of the monsoon season. In the second stage, the monitoring network is then designed separately for monsoon and non-monsoon periods by optimizing the number and locations of sampling sites, using a modified Sanders approach. The impacts of human interventions on the design of the sampling net are quantified geospatially by estimating diffuse pollution loads and verified with land use map. To demonstrate the proposed methodology, the Kali River basin in the western Uttar Pradesh state of India was selected as a study area. The final design suggests consequential pre- and post-monsoonal changes in the location and priority of water quality monitoring stations based on the seasonal variation of point and diffuse pollution loadings.

  12. The effect of the sample size and location on contrast ultrasound measurement of perfusion parameters.

    PubMed

    Leinonen, Merja R; Raekallio, Marja R; Vainio, Outi M; Ruohoniemi, Mirja O; O'Brien, Robert T

    2011-01-01

    Contrast-enhanced ultrasound can be used to quantify tissue perfusion based on region of interest (ROI) analysis. The effect of the location and size of the ROI on the obtained perfusion parameters has been described in phantom, ex vivo and in vivo studies. We assessed the effects of location and size of the ROI on perfusion parameters in the renal cortex of 10 healthy, anesthetized cats using Definity contrast-enhanced ultrasound to estimate the importance of the ROI on quantification of tissue perfusion with contrast-enhanced ultrasound. Three separate sets of ROIs were placed in the renal cortex, varying in location, size or depth. There was a significant inverse association between increased depth or increased size of the ROI and peak intensity (P < 0.05). There was no statistically significant difference in the peak intensity between the ROIs placed in a row in the near field cortex. There was no significant difference in the ROIs with regard to arrival time, time to peak intensity and wash-in rate. When comparing two different ROIs in a patient with focal lesions, such as suspected neoplasia or infarction, the ROIs should always be placed at same depth and be as similar in size as possible.

  13. Seasonal rationalization of river water quality sampling locations: a comparative study of the modified Sanders and multivariate statistical approaches.

    PubMed

    Varekar, Vikas; Karmakar, Subhankar; Jha, Ramakar

    2016-02-01

    The design of surface water quality sampling location is a crucial decision-making process for rationalization of monitoring network. The quantity, quality, and types of available dataset (watershed characteristics and water quality data) may affect the selection of appropriate design methodology. The modified Sanders approach and multivariate statistical techniques [particularly factor analysis (FA)/principal component analysis (PCA)] are well-accepted and widely used techniques for design of sampling locations. However, their performance may vary significantly with quantity, quality, and types of available dataset. In this paper, an attempt has been made to evaluate performance of these techniques by accounting the effect of seasonal variation, under a situation of limited water quality data but extensive watershed characteristics information, as continuous and consistent river water quality data is usually difficult to obtain, whereas watershed information may be made available through application of geospatial techniques. A case study of Kali River, Western Uttar Pradesh, India, is selected for the analysis. The monitoring was carried out at 16 sampling locations. The discrete and diffuse pollution loads at different sampling sites were estimated and accounted using modified Sanders approach, whereas the monitored physical and chemical water quality parameters were utilized as inputs for FA/PCA. The designed optimum number of sampling locations for monsoon and non-monsoon seasons by modified Sanders approach are eight and seven while that for FA/PCA are eleven and nine, respectively. Less variation in the number and locations of designed sampling sites were obtained by both techniques, which shows stability of results. A geospatial analysis has also been carried out to check the significance of designed sampling location with respect to river basin characteristics and land use of the study area. Both methods are equally efficient; however, modified Sanders

  14. Stack Flow Rate Changes and the ANSI/N13.1-1999 Qualification Criteria: Application to the Hanford Canister Storage Building Stack

    SciTech Connect

    Flaherty, Julia E.; Glissmeyer, John A.

    2016-02-29

    The Canister Storage Building (CSB), located in the 200-East Area of the Hanford Site, is a 42,000 square foot facility used to store spent nuclear fuel from past activities at the Hanford Site. Because the facility has the potential to emit radionuclides into the environment, its ventilation exhaust stack has been equipped with an air monitoring system. Subpart H of the National Emissions Standards for Hazardous Air Pollutants requires that a sampling probe be located in the exhaust stack in accordance with criteria established by the American National Standards Institute/Health Physics Society Standard N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities.

  15. Analytical results and sample locations of reanalyzed NURE stream-sediment and soil samples for the Humboldt River basin mineral-environmental assessment, northern Nevada

    USGS Publications Warehouse

    Folger, H. W.

    2000-01-01

    The U.S. Geological Survey (USGS), in cooperation with the Bureau of Land Management (BLM), began a study in 1996 to describe to the geochemistry of the Humboldt River Basin. The principal sample media evaluated are stream-sediment and soil samples retrieved from the National Uranium Resource Evaluation (NURE) archives located in Denver, Colorado. Samples were retrieved from the Wells, McDermitt, Vya, Lovelock, Winnemucca, Elko, Ely, Millett, Reno, and Tonopah 1? x 2? quadrangles in northern Nevada. The data are appropriate for large-scale reconnaissance resource evaluations and landscape geochemical-geoenvironmental evaluations. The analytical results are presented in this report.

  16. Salinity of ground water at sampling wells located in southeastern Nassau County, Long Island, New York

    USGS Publications Warehouse

    Lusczynski, Norbert J.

    1950-01-01

    In 1939, a special program for the systematic collection of chloride data in southeastern Nassau County was inaugurated in which three agencies participated. The Nassau County Department of Public Works constructed the sampling wells, the Ground Water Branch of the U.S. Geological Survey began to collect at period intervals water samples which were analysed at the Mount Prospect Laboratory of the New York Department of Water Supply, Gas and Electricity, The Nassau County Department of Public Works and the U.S. Geological Survey have continued financial cooperation for the maintenance of this program up to the present time.

  17. Using object-based image analysis to guide the selection of field sample locations

    USDA-ARS?s Scientific Manuscript database

    One of the most challenging tasks for resource management and research is designing field sampling schemes to achieve unbiased estimates of ecosystem parameters as efficiently as possible. This study focused on the potential of fine-scale image objects from object-based image analysis (OBIA) to be u...

  18. Space environmental effects on polymer matrix composites as a function of sample location on LDEF

    NASA Technical Reports Server (NTRS)

    Tennyson, R. C.; Cool, G. R.; Zimcik, D. G.

    1995-01-01

    This paper presents results on the effect of circumferential location on the variation in solar absorptance (alpha(sub S)) and infrared emittance (epsilon) for five different polymer matrix composites (PMC), and variations in erosion depth due to atomic oxygen (AO) for fourteen different PMC materials. In addition, a chemical content design parameter (gamma) has been found that correlates well with the erosion yield obtained from space flight data and hyperthermal AO tests for hydrocarbon polymeric materials. This parameter defines the ratio of the total number of atoms in a repeat monomer unit to the difference between the total carbon content and the total number of intermolecular oxygen atoms in the same repeat unit.

  19. Apollo 14 coarse fines (4-10 mm) sample location and classification

    NASA Technical Reports Server (NTRS)

    Kramer, F. E.; Twedell, D. B.

    1977-01-01

    The 4 to 10 mm sieve fraction from the soil samples collected during the Apollo 14 Mission was identified and described. Examination and description of the fines were carried out in nitrogen-filled, stainless steel cabinets during a general examination of the Apollo 14 sample collection. Each particle was held between forceps, dusted in a jet of N2, and placed on a teflon-covered stage. They were examined with a binocular microscope, separated by lithology, and the lithologic types described. Weights of individual particles in the fraction ranged from about 0.10 to 0.50 gm, large enough in size for studies of age, chemistry, and petrology to be accomplished.

  20. Passive sampling effects and landscape location alter associations between species traits and response to fragmentation.

    PubMed

    Thornton, Daniel; Branch, Lyn; Sunquist, Mel

    2011-04-01

    As tropical reserves become smaller and more isolated, the ability of species to utilize fragmented landscapes will be a key determinant of species survival. Although several ecological and life history traits commonly are associated with vulnerability to fragmentation, the combination of traits that are most highly influential and the effectiveness of those traits in predicting vulnerability across distinct landscapes, remains poorly understood. We studied use of forest fragments by 25 mid- and large-sized neotropical mammals in Guatemala to determine how seven species traits influence vulnerability to fragmentation. We measured vulnerability in two ways: one measure that did not remove passive sampling effects (proportion of fragments occupied), and one that did (difference in occupancy rates within continuous and fragmented sites). We also examined the influence of species traits on patch occupancy rates of the same set of mammals on two landscapes in Mexico. When not accounting for passive sampling effects, body size, home range size, and vulnerability to hunting influenced how species responded to fragmentation. However, after controlling for passive sampling effects, only vulnerability to hunting strongly influenced sensitivity to fragmentation. Species that were heavily hunted were much less common in forest patches than in continuous forest sites of the same sampling size. The cross-landscape comparison revealed both similarities and differences in the species traits that influenced patch occupancy patterns on each landscape. Given the ubiquity of hunting in tropical environments, our findings indicate that management efforts in fragmented landscapes that do not account for hunting pressure may be ineffective in conserving heavily hunted tropical species. Our study also indicates that species traits may be useful in predicting relative patch occupancy rates and/or vulnerability to fragmentation across distinct landscapes, but that caution must be used as

  1. Determining the relative importance of soil sample locations to predict risk of child lead exposure.

    PubMed

    Zahran, Sammy; Mielke, Howard W; McElmurry, Shawn P; Filippelli, Gabriel M; Laidlaw, Mark A S; Taylor, Mark P

    2013-10-01

    Soil lead in urban neighborhoods is a known predictor of child blood lead levels. In this paper, we address the question where one ought to concentrate soil sample collection efforts to efficiently predict children at-risk for soil Pb exposure. Two extensive data sets are combined, including 5467 surface soil samples collected from 286 census tracts, and geo-referenced blood Pb data for 55,551 children in metropolitan New Orleans, USA. Random intercept least squares, random intercept logistic, and quantile regression results indicate that soils collected within 1m adjacent to residential streets most reliably predict child blood Pb outcomes in child blood Pb levels. Regression decomposition results show that residential street soils account for 39.7% of between-neighborhood explained variation, followed by busy street soils (21.97%), open space soils (20.25%), and home foundation soils (18.71%). Just as the age of housing stock is used as a statistical shortcut for child risk of exposure to lead-based paint, our results indicate that one can shortcut the characterization of child risk of exposure to neighborhood soil Pb by concentrating sampling efforts within 1m and adjacent to residential and busy streets, while significantly reducing the total costs of collection and analysis. This efficiency gain can help advance proactive upstream, preventive methods of environmental Pb discovery.

  2. CSD Fans and Disjointed CSD Bundles: Recovery of The Spatial Sample Locations from CSD Ensembles

    NASA Astrophysics Data System (ADS)

    Marsh, B. D.; Zieg, M. J.

    2001-05-01

    Volcanic rock captures magmatic time through eruption and quenching, but its spatial connection to the parent magma has been scrambled. It is an aliquot of magma from an unknown position within the magmatic body, and its relation to other coeval and comagmatic samples is also unknown. P-T determinations, although invaluable are not precise enough to arrange successive samples with any real certainty within the magmatic regime. This is a severe limitation in using lavas to infer magma chamber processes. We have developed a technique that allows the relative spatial order of comagmatic samples in the magmatic environment to be recovered. The method rests on a recent advance in CSD analysis. We have been able to show that CSD slope (S) and intercept (I) are linked through a universal relation (Zieg and Marsh, 2001, sub. J. Pet.). The CSDs of all igneous rocks fall on this I-S curve. Moreover, it can also be shown that CSD slope is inversely related to mean crystal size (S=1/Lm) and also that mean crystal size is the product of mean growth rate (G) and solidification time (Dt). That is, Lm = GDt. (The exact form of this growth law is completely arbitrary.). Because the rate of solidification front (SF) advance decreases as it propagates inward, local solidification time increases and so does mean crystal size, but nucleation rate must, in accordance with the universal I-S relation, decrease. The CSD slope thus must decrease systematically inward in the body, and a series of spatially contiguous CSDs thus form a fan. (This solves the mystery of CSD pivot points and of the often noticed correlation between CSD slope and intercept (Marsh et al., 1995 EOS).) A series of fanning CSDs for the Sudbury norite melt sheet match exactly the CSD fan calculated from the I - S relation. CSD slope decreases inward from the margins of the body as Lm increases due to increasing solidification time. Given a set of blind samples from a pluton, the order of the CSDs in a fan determines

  3. Location and Age Database for Selected Foraminifer Samples Collected by Exxon Petroleum Geologists in California

    USGS Publications Warehouse

    Brabb, Earl E.; Parker, John M.

    2003-01-01

    Most of the geologic maps published for central California before 1960 were made without the benefit of age determinations from microfossils. The ages of Cretaceous and Tertiary rocks in the mostly poorly exposed and structurally complex sedimentary rocks represented in the Coast Ranges are critical in determining stratigraphic succession or lack of it, and in determining whether the juxtaposition of similar appearing but different age formations means a fault is present. Since the 1930’s, at least, oil company geologists have used microfossils to assist them in geologic mapping and in determining the environments of deposition of the sediment containing the microfossils. This information has been so confidential that some companies even coded the names of foraminifers to prevent disclosure. In the past 20 years, however, the attitude of petroleum companies about this information has changed, and many of the formerly confidential materials and reports are now available. We report here on 1,964 Exxon foraminifer samples mostly from surface localities in the San Francisco Bay region, and elsewhere in California. Most but not all the samples were plotted on U. S. Geological Survey (USGS) 7.5’ topographic maps or on obsolete USGS 15’ maps. The information from the slides can be used to update geologic maps prepared without the benefit of microfossil data, to analyze the depth and temperature of ocean water covering parts of California during the Mesozoic and Cenozoic Eras, and for solving nomenclature and other scientific problems. A similar report on more than 30,000 slides for surface samples collected by Chevron geologists has been released (Brabb and Parker, 2003), and another report provides information on slides for more than 2000 oil test wells in Northern California (Brabb, Powell, and Brocher, 2001).

  4. Occurrence of carbazoles in dust and air samples from different locations in Germany.

    PubMed

    Fromme, Hermann; Mi, Wenying; Lahrz, Thomas; Kraft, Martin; Aschenbrenner, Bettina; Bruessow, Bianca; Ebinghaus, Ralf; Xie, Zhiyong; Fembacher, Ludwig

    2017-08-12

    9H-carbazole is generated from incomplete combustion of diverse fossil fuels and biomass, in tobacco smoke and from industrial processes, while halogenated carbazoles have natural and anthropogenic sources. We analyzed 9H-carbazole and 14 halogenated carbazoles in dust samples from 14 schools, 13 daycare centers, and 13 residences, as well as 5 indoor air samples from residences in Munich, Germany. Overall, we present first data of various carbazoles in different indoor environments without visible combustion sources. The median (95th percentile) values of the halogenated analytes mainly detected in the entire study group were 10.3ng/g (308ng/g) for 9H-carbazole, 13.3ng/g (735ng/g) for 3,6-dichloro-9H-carbazole, 6.2ng/g (159ng/g) for 1,3,6-tribromo-9H-carbazole, and 1.2ng/g (21.1ng/g) for 2,7-dibromo-9H-carbazole. For most of the target analytes, the highest concentrations were observed in dust samples from schools, and the lowest were found in residences. In the air samples, all analytes were found only at low levels, with median values of 7.7pg/m(3) for 9H-carbazole and 6.1pg/m(3) for 2,3,6,7-tetrachloro-9H-carbazole. For 9H-carbazole, "typical" and "high" non-dietary intake of children through dust ingestion using median and 95th percentile values were calculated to be 0.03ng/kg b.w. and 1.1ng/kg b.w. daily, respectively. Due to limited toxicological information and exposure data for other relevant pathways (e.g., dietary intake), the risk assessment is inconclusive. Nevertheless, there are indications that 9H-carbazole has carcinogenic properties and that halogenated carbazoles have dioxin-like toxicities. Therefore, further research is essential. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Location and sampling of aqueous and hydrothermal deposits in martian impact craters.

    PubMed

    Newsom, H E; Hagerty, J J; Thorsos, I E

    2001-01-01

    Do large craters on Mars represent sites that contain aqueous and hydrothermal deposits that provide clues to astrobiological processes? Are these materials available for sampling in large craters? Several lines of evidence strongly support the exploration of large impact craters to study deposits important for astrobiology. The great depth of impact craters, up to several kilometers relative to the surrounding terrain, can allow the breaching of local aquifers, providing a source of water for lakes and hydrothermal systems. Craters can also be filled with water from outflow channels and valley networks to form large lakes with accompanying sedimentation. Impact melt and uplifted basement heat sources in craters > 50 km in diameter should be sufficient to drive substantial hydrothermal activity and keep crater lakes from freezing for thousands of years, even under cold climatic conditions. Fluid flow in hydrothermal systems is focused at the edges of large planar impact melt sheets, suggesting that the edge of the melt sheets will have experienced substantial hydrothermal alteration and mineral deposition. Hydrothermal deposits, fine-grained lacustrine sediments, and playa evaporite deposits may preserve evidence for biogeochemical processes that occurred in the aquifers and craters. Therefore, large craters may represent giant Petri dishes for culturing preexisting life on Mars and promoting biogeochemical processes. Landing sites must be identified in craters where access to the buried lacustrine sediments and impact melt deposits is provided by processes such as erosion from outflow channels, faulting, aeolian erosion, or excavation by later superimposed cratering events. Very recent gully formation and small impacts within craters may allow surface sampling of organic materials exposed only recently to the harsh oxidizing surface environment.

  6. Different Location Sampling Frequencies by Satellite Tags Yield Different Estimates of Migration Performance: Pooling Data Requires a Common Protocol

    PubMed Central

    Tanferna, Alessandro; López-Jiménez, Lidia; Blas, Julio; Hiraldo, Fernando; Sergio, Fabrizio

    2012-01-01

    Background Migration research is in rapid expansion and increasingly based on sophisticated satellite-tracking devices subject to constant technological refinement, but is still ripe with descriptive studies and in need of meta-analyses looking for emergent generalisations. In particular, coexistence of studies and devices with different frequency of location sampling and spatial accuracy generates doubts of data compatibility, potentially preventing meta-analyses. We used satellite-tracking data on a migratory raptor to: (1) test whether data based on different location sampling frequencies and on different position subsampling approaches are compatible, and (2) seek potential solutions that enhance compatibility and enable eventual meta-analyses. Methodology/Principal Findings We used linear mixed models to analyse the differences in the speed and route length of the migration tracks of 36 Black kites (Milvus migrans) satellite-tagged with two different types of devices (Argos vs GPS tags), entailing different regimes of position sampling frequency. We show that different location sampling frequencies and data subsampling approaches generate large (up to 33%) differences in the estimates of route length and migration speed of this migratory bird. Conclusions/Significance Our results show that the abundance of locations available for analysis affects the tortuosity and realism of the estimated migration path. To avoid flaws in future meta-analyses or unnecessary loss of data, we urge researchers to reach an agreement on a common protocol of data presentation, and to recognize that all transmitter-based studies are likely to underestimate the actual distance traveled by the marked animal. As ecological research becomes increasingly technological, new technologies should be matched with improvements in analytical capacity that guarantee data compatibility. PMID:23166742

  7. Different location sampling frequencies by satellite tags yield different estimates of migration performance: pooling data requires a common protocol.

    PubMed

    Tanferna, Alessandro; López-Jiménez, Lidia; Blas, Julio; Hiraldo, Fernando; Sergio, Fabrizio

    2012-01-01

    Migration research is in rapid expansion and increasingly based on sophisticated satellite-tracking devices subject to constant technological refinement, but is still ripe with descriptive studies and in need of meta-analyses looking for emergent generalisations. In particular, coexistence of studies and devices with different frequency of location sampling and spatial accuracy generates doubts of data compatibility, potentially preventing meta-analyses. We used satellite-tracking data on a migratory raptor to: (1) test whether data based on different location sampling frequencies and on different position subsampling approaches are compatible, and (2) seek potential solutions that enhance compatibility and enable eventual meta-analyses. We used linear mixed models to analyse the differences in the speed and route length of the migration tracks of 36 Black kites (Milvus migrans) satellite-tagged with two different types of devices (Argos vs GPS tags), entailing different regimes of position sampling frequency. We show that different location sampling frequencies and data subsampling approaches generate large (up to 33%) differences in the estimates of route length and migration speed of this migratory bird. Our results show that the abundance of locations available for analysis affects the tortuosity and realism of the estimated migration path. To avoid flaws in future meta-analyses or unnecessary loss of data, we urge researchers to reach an agreement on a common protocol of data presentation, and to recognize that all transmitter-based studies are likely to underestimate the actual distance traveled by the marked animal. As ecological research becomes increasingly technological, new technologies should be matched with improvements in analytical capacity that guarantee data compatibility.

  8. Locating and quantifying PCB sources in Chicago: receptor modeling and field sampling.

    PubMed

    Hsu, Ying-Kuang; Holsen, Thomas M; Hopke, Philip K

    2003-02-15

    Potential source contribution function (PSCF) modeling using polychlorinated biphenyl (PCB) concentrations measured in the Chicago area resolved three PCB source sectors. They were (i) the direction northwest of Chicago, (ii) the direction southwest of Chicago, and (iii) the south side of Chicago in the neighborhood of Lake Calumet. The area south of Chicago was further examined by taking upwind/ downwind samples near a landfill and sludge drying beds. Results identified the sludge drying beds and a large landfill as PCB sources to the atmosphere. Another PCB source identified in Chicago was a transformer storage yard. This site had the highest upwind/downwind concentration increments in this study (downwind PCB concentrations were more than 5 times those in the upwind air). These PCB sources were characterized in terms of inventories, emission rates, contributions, and PCB congener profiles (fingerprints). Preliminarily results indicate that the sludge may emit up to 90 kg/yr of PCBs to the air. This amount is probably not a significant contribution of PCBs to the Chicago atmosphere on the basis of dispersion modeling results and a simple box model.

  9. Long-term environmental trends: selection of sampling locations in a reactor-aquatic cooling system.

    PubMed

    Revsin, B K; Watson, J E

    1993-02-01

    The study objective was to determine whether environmental radionuclide accumulations were occurring in an aquatic system with a 13-y history of supplying a power plant with reactor-cooling water as well as receiving plant discharge. The aquatic system consisted of the following: 1) a reactor-cooling lake; 2) a secondary lake approximately 8 km downstream; and 3) a small stream that interfaced with the two lakes. Gamma-emitting radionuclides were identified and quantified in samples of benthic sediments obtained from representative areas of the aquatic system. This study demonstrated that in a reactor-aquatic cooling system, the component of the aquatic system most likely to experience radionuclide accumulation will not necessarily be the reactor-cooling lake, but will be that component of the aquatic system whose benthic sediments contain the highest concentrations of organic matter. Further, it was shown that the quantity of oxidizable organic matter present in a sediment is a good predictor or marker for potential sites of radionuclide accumulation (i.e., 60Co and 137Cs).

  10. Efficient DNP NMR of Membrane Proteins: Sample Preparation Protocols, Sensitivity, and Radical Location

    PubMed Central

    Liao, Shu Y.; Lee, Myungwoon; Wang, Tuo; Sergeyev, Ivan V.; Hong, Mei

    2016-01-01

    Although dynamic nuclear polarization (DNP) has dramatically enhanced solid-state NMR spectral sensitivities of many synthetic materials and some biological macromolecules, recent studies of membrane-protein DNP using exogenously doped paramagnetic radicals as polarizing agents have reported varied and sometimes surprisingly limited enhancement factors. This motivated us to carry out a systematic evaluation of sample preparation protocols for optimizing the sensitivity of DNP NMR spectra of membrane-bound peptides and proteins at cryogenic temperatures of ~110 K. We show that mixing the radical with the membrane by direct titration instead of centrifugation gives a significant boost to DNP enhancement. We quantify the relative sensitivity enhancement between AMUPol and TOTAPOL, two commonly used radicals, and between deuterated and protonated lipid membranes. AMUPol shows ~4 fold higher sensitivity enhancement than TOTAPOL, while deuterated lipid membrane does not give net higher sensitivity for the membrane peptides than protonated membrane. Overall, a ~100 fold enhancement between the microwave-on and microwave-off spectra can be achieved on lipid-rich membranes containing conformationally disordered peptides, and absolute sensitivity gains of 105–160 can be obtained between low-temperature DNP spectra and high-temperature non-DNP spectra. We also measured the paramagnetic relaxation enhancement of lipid signals by TOTAPOL and AMUPol, to determine the depths of these two radicals in the lipid bilayer. Our data indicate a bimodal distribution of both radicals, a surface-bound fraction and a membrane-bound fraction where the nitroxides lie at ~10 Å from the membrane surface. TOTAPOL appears to have a higher membrane-embedded fraction than AMUPol. These results should be useful for membrane-protein solid-state NMR studies under DNP conditions and provide insights into how biradicals interact with phospholipid membranes. PMID:26873390

  11. Efficient DNP NMR of membrane proteins: sample preparation protocols, sensitivity, and radical location.

    PubMed

    Liao, Shu Y; Lee, Myungwoon; Wang, Tuo; Sergeyev, Ivan V; Hong, Mei

    2016-03-01

    Although dynamic nuclear polarization (DNP) has dramatically enhanced solid-state NMR spectral sensitivities of many synthetic materials and some biological macromolecules, recent studies of membrane-protein DNP using exogenously doped paramagnetic radicals as polarizing agents have reported varied and sometimes surprisingly limited enhancement factors. This motivated us to carry out a systematic evaluation of sample preparation protocols for optimizing the sensitivity of DNP NMR spectra of membrane-bound peptides and proteins at cryogenic temperatures of ~110 K. We show that mixing the radical with the membrane by direct titration instead of centrifugation gives a significant boost to DNP enhancement. We quantify the relative sensitivity enhancement between AMUPol and TOTAPOL, two commonly used radicals, and between deuterated and protonated lipid membranes. AMUPol shows ~fourfold higher sensitivity enhancement than TOTAPOL, while deuterated lipid membrane does not give net higher sensitivity for the membrane peptides than protonated membrane. Overall, a ~100 fold enhancement between the microwave-on and microwave-off spectra can be achieved on lipid-rich membranes containing conformationally disordered peptides, and absolute sensitivity gains of 105-160 can be obtained between low-temperature DNP spectra and high-temperature non-DNP spectra. We also measured the paramagnetic relaxation enhancement of lipid signals by TOTAPOL and AMUPol, to determine the depths of these two radicals in the lipid bilayer. Our data indicate a bimodal distribution of both radicals, a surface-bound fraction and a membrane-bound fraction where the nitroxides lie at ~10 Å from the membrane surface. TOTAPOL appears to have a higher membrane-embedded fraction than AMUPol. These results should be useful for membrane-protein solid-state NMR studies under DNP conditions and provide insights into how biradicals interact with phospholipid membranes.

  12. Stacking with stochastic cooling

    NASA Astrophysics Data System (ADS)

    Caspers, Fritz; Möhl, Dieter

    2004-10-01

    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.

  13. Zirconia coated stir bar sorptive extraction combined with large volume sample stacking capillary electrophoresis-indirect ultraviolet detection for the determination of chemical warfare agent degradation products in water samples.

    PubMed

    Li, Pingjing; Hu, Bin; Li, Xiaoyong

    2012-07-20

    In this study, a sensitive, selective and reliable analytical method by combining zirconia (ZrO₂) coated stir bar sorptive extraction (SBSE) with large volume sample stacking capillary electrophoresis-indirect ultraviolet (LVSS-CE/indirect UV) was developed for the direct analysis of chemical warfare agent degradation products of alkyl alkylphosphonic acids (AAPAs) (including ethyl methylphosphonic acid (EMPA) and pinacolyl methylphosphonate (PMPA)) and methylphosphonic acid (MPA) in environmental waters. ZrO₂ coated stir bar was prepared by adhering nanometer-sized ZrO₂ particles onto the surface of stir bar with commercial PDMS sol as adhesion agent. Due to the high affinity of ZrO₂ to the electronegative phosphonate group, ZrO₂ coated stir bars could selectively extract the strongly polar AAPAs and MPA. After systematically optimizing the extraction conditions of ZrO₂-SBSE, the analytical performance of ZrO₂-SBSE-CE/indirect UV and ZrO₂-SBSE-LVSS-CE/indirect UV was assessed. The limits of detection (LODs, at a signal-to-noise ratio of 3) obtained by ZrO₂-SBSE-CE/indirect UV were 13.4-15.9 μg/L for PMPA, EMPA and MPA. The relative standard deviations (RSDs, n=7, c=200 μg/L) of the corrected peak area for the target analytes were in the range of 6.4-8.8%. Enhancement factors (EFs) in terms of LODs were found to be from 112- to 145-fold. By combining ZrO₂ coating SBSE with LVSS as a dual preconcentration strategy, the EFs were magnified up to 1583-fold, and the LODs of ZrO₂-SBSE-LVSS-CE/indirect UV were 1.4, 1.2 and 3.1 μg/L for PMPA, EMPA, and MPA, respectively. The RSDs (n=7, c=20 μg/L) were found to be in the range of 9.0-11.8%. The developed ZrO₂-SBSE-LVSS-CE/indirect UV method has been successfully applied to the analysis of PMPA, EMPA, and MPA in different environmental water samples, and the recoveries for the spiked water samples were found to be in the range of 93.8-105.3%.

  14. Predicting tumour location in radical prostatectomy specimens: same-patient comparisons of 21-sample versus sextant biopsy.

    PubMed

    De Laet, Kevin; de la Taille, Alexandre; Ploussard, Guillaume; Hoznek, Andras; Vordos, Dimitrios; Yiou, René; Allory, Yves; Azoulay, Sandy; Abbou, Claude; Salomon, Laurent

    2009-09-01

    To determine the value of a 21-sample biopsy protocol in predicting tumour localization in radical prostatectomy (RP) specimens, compared with sextant biopsies. In all, 300 consecutive patients underwent 21-sample prostate biopsies, followed by RP. The protocol consisted of sextant, three midline, six far lateral and six transitional zone biopsies. Tumour locations on biopsies and RP specimens were compared. The sensitivity, specificity, positive (PPV) and negative predictive value (NPV) and accuracy were calculated. There was no difference between sextant and 21-sample biopsies for sensitivity (38% vs 36%; P=0.50) and specificity (84% vs 87%; P=0.46), but the NPV was higher for 21-sample biopsies (57% vs 68% ; P<0.001). The PPV was higher in the sextant biopsies (74% vs 59%; P=0.007). Sextant, transitional zone and far lateral biopsies were re-grouped in six regions. Compared with 21-sample biopsies, sensitivity (54%) and PPV (79%) were higher (P<0.001), while specificity (74%) and NPV (46%) were lower (P=0.05 and P=0.001, respectively). A negative biopsy does not confirm the absence of cancer in the corresponding site in the RP specimen in a sextant or 21-sample biopsy protocol and cannot be used as a prognostic element before RP. A positive biopsy does not always correspond with a tumour in the same zone of the RP specimen. When 21-sample biopsies are re-grouped in to six regions, the value of a positive biopsy increases. A positive biopsy corresponds thus to a tumour in the same region, rather than in precisely the same location. The results of this study could help in the biopsy protocol used for making surgical decisions, e.g. preserving the bladder neck or neurovascular bundles.

  15. Photochemical production of organic matter triplet states in water samples from mountain lakes, located below or above the tree line.

    PubMed

    De Laurentiis, Elisa; Minella, Marco; Maurino, Valter; Minero, Claudio; Brigante, Marcello; Mailhot, Gilles; Vione, Davide

    2012-08-01

    The production of triplet states (T(*)) of chromophoric dissolved organic matter (CDOM), reacting with the probe molecule 2,4,6-trimethylphenol (TMP) was measured upon irradiation of water samples, taken from lakes located in a mountain area (NW Italy) between 1450 and 2750 m above sea level. The lakes are located below or above the tree line and surrounded by different vegetation types (trees, alpine meadows or exposed rocks). The most photoactive samples belonged to lakes below the tree line and their fluorescence spectra and CDOM optical features suggested the presence of a relatively elevated amount of humic (allochthonous) material. The lowest (negligible) photoactivity was found for a lake surrounded by exposed rocks. Its CDOM showed an important autochthonous contribution (due to in-lake productivity) and considerably higher spectral slope compared to the other samples, suggesting low CDOM molecular weight and/or aromaticity. Among the samples, CDOM photoactivity (measured as the rate of TMP-reactive T(*) photoproduction) decreased with changing vegetation type in the order: trees, meadows, rocks. It could be connected with decreasing contribution from catchment runoff and increasing contribution from autochthonous processes and possibly precipitation.

  16. Estrogenic and esterase-inhibiting potency in rainwater in relation to pesticide concentrations, sampling season and location.

    PubMed

    Hamers, Timo; van den Brink, Paul J; Mos, Lizzy; van der Linden, Sander C; Legler, Juliette; Koeman, Jan H; Murk, Albertinka J

    2003-01-01

    In a year-round monitoring program (1998), pesticide composition and toxic potency of the mix of pollutants present in rainwater were measured. The goal of the study was to relate atmospheric deposition of toxic potency and pesticide composition to each other and to sampling period and local agricultural activity. Rainwater was collected in 26 consecutive periods of 14 days in a background location (BACK) and in two locations representative for different agricultural practices, i.e. intensive greenhouse horticulture (HORT) and flower bulb culture (BULB). Samples were chemically analyzed for carbamate (CARB), organophosphate (OP) and organochlorine (OC) pesticides and metabolites. Esterase inhibiting potency of rainwater extracts was measured in a specially developed bio-assay with honeybee esterases and was expressed as an equivalent concentration of the model inhibitor dichlorvos. Estrogenic potency of the extracts was measured in the ER-CALUX reporter gene assay and was expressed as an equivalent concentration of estradiol. Multivariate principal component analysis (PCA) techniques proved to be valuable tools to analyze the numerous pesticide concentrations in relation to toxic potency, sampling location, and sampling season. Pesticide composition in rainwater depended much more on sampling season than on sampling location, but differences between and were mainly attributed to local differences in agricultural practice. On average, the esterase inhibiting potency exceeded the maximum permissible concentration set for dichlorvos in The Netherlands, and was significantly higher in than in and . Esterase inhibition correlated significantly with OP and CARB concentrations, as expected given the working mechanism of these insecticides. The estrogenic potency incidentally exceeded NOEC levels reported for aquatic organisms and was highest in . Although estrogenic potency of rainwater correlated with OC concentrations, the ER-CALUX responses could not be attributed to

  17. The Association Between Geographic Location and Anxiety and Depression in Transgender Individuals: An Exploratory Study of an Online Sample

    PubMed Central

    Sinnard, Morgan T.; Raines, Christopher R.; Budge, Stephanie L.

    2016-01-01

    Abstract Purpose: Research has demonstrated associations between discrimination and mental health in lesbian, gay, bisexual, and transgender populations. However, little is known about the influence of geographic location on psychological distress in these populations, particularly among transgender people. Methods: This secondary analysis conducted on a national sample of transgender individuals (N=414) offers a preliminary understanding of the effects of geographic location on psychological distress (i.e., anxiety and depression). A univariate analysis of variance was calculated to determine this relationship. Results: The West South Central division (i.e., Arkansas, Louisiana, Oklahoma, and Texas) revealed highest psychological distress. Conclusion: Results suggest an urgent need for transgender-competent healthcare in this division. PMID:28861531

  18. A comparison between respondent-driven sampling and time-location sampling among men who have sex with men in Shenzhen, China.

    PubMed

    Zhao, Jin; Cai, Rui; Chen, Lin; Cai, Wende; Yang, Zhengrong; Richardus, Jan Hendrik; de Vlas, Sake J

    2015-10-01

    Men who have sex with men (MSM) are a key population for HIV control and prevention in China. It is difficult to acquire representative samples of this hidden population. Respondent-driven sampling (RDS), based on peer referral, and time-location sampling (TLS) based on random selection of venue-day-time periods, are among the most commonly used sampling methods. However, differences in HIV-related characteristics of MSM recruited by these two methods have not been fully evaluated. We compared sociodemographics, risk behaviors, utilization of HIV-related intervention services, and HIV/syphilis infection rates between samples of 621 RDS MSM and 533 TLS MSM in Shenzhen, China in 2010. We found that the HIV prevalence was comparable in RDS and TLS MSM. TLS recruited larger proportions of more marginalized MSM than RDS: MSM recruited by TLS were older, less educated and more likely to be migrants (without Shenzhen hukou registration), to be non-gay identified and to engage in risky sexual behaviors. On the other hand, MSM recruited by TLS were more likely to have been covered by HIV-related intervention services. To conclude, in Shenzhen, TLS is more effective to reach the marginalized population of MSM. But because TLS can only reach MSM who physically attend venues and HIV-related intervention services are already commonly available at gay venues in Shenzhen, RDS is more informative for allocating prevention efforts than TLS. Furthermore, researchers and public health authorities should take into account the different sample compositions of RDS and TLS and apply sampling methods consistently when evaluating trends over time.

  19. Classification of Greek Mentha pulegium L. (Pennyroyal) samples, according to geographical location by Fourier transform infrared spectroscopy.

    PubMed

    Kanakis, Charalabos D; Petrakis, Eleftherios A; Kimbaris, Athanasios C; Pappas, Christos; Tarantilis, Petros A; Polissiou, Moschos G

    2012-01-01

    Mentha pulegium L. (pennyroyal) is one of the four most commercially important Mentha species, even it is not a cultivated plant. It can be abundantly located in the Iberian Peninsula and North African countries. In Greece it grows in the wild and it is scattered all over the country. Pennyroyal is best known for its essential oil, with Spain and Morocco being the largest producers in the world. Mid-infrared spectroscopy has been applied to determine the origin of various samples. In this work Fourier transform infrared spectroscopy (FT-IR) combined with canonical discriminant analysis has been applied to distinguish 70 Greek pennyroyal samples according to their collection areas. Pennyroyal nonpolar organic extracts were prepared using ultrasound-assisted solvent extraction. The spectra of the extracts were recorded in the range of 4000-400 cm(-1) and the best discrimination was achieved in the spectral region 1720-1650 cm(-1) . Spectral features for the discrimination of pennyroyal samples among the different collection areas occur primarily in the carbonyl region and are correlated with the main volatile constituents of the extracts (menthone, isomenthone, pulegone, piperitone). All areas were easily differentiated by canonical discriminant analysis. The percentages of correct classification and validation were 94.3 and 90.0%, respectively. The combination of FT-IR spectroscopy and multivariate analysis provides a rapid and ambient method to discriminate pennyroyal samples in terms of geographical origin. Copyright © 2011 John Wiley & Sons, Ltd.

  20. Stack gas treatment

    DOEpatents

    Reeves, Adam A.

    1977-04-12

    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.

  1. Red Mud Stacking

    NASA Astrophysics Data System (ADS)

    Bélanger, Marie-J.

    The red mud slurry "stacking" method used in many Alcan Plants has been developed in the 1980's. The aim of this technique is to use minimum space for the disposal of the residue and to rapidly obtain consolidated material. The consistency of the mud slurry plays a key role in the steepness (angle) of the stacking slope.

  2. Drinking locations and alcohol-related harm: Cross-sectional and longitudinal associations in a sample of young Swiss men.

    PubMed

    Studer, Joseph; Baggio, Stéphanie; Deline, Stéphane; N'Goran, Alexandra A; Henchoz, Yves; Mohler-Kuo, Meichun; Daeppen, Jean-Bernard; Gmel, Gerhard

    2015-07-01

    Alcohol consumption--in particular drinking volume (DV) and risky single occasion drinking (RSOD)--has been related to a wide range of negative consequences and health problems. Previous studies also suggested that drinking in certain locations may be more strongly associated with the occurrence of alcohol-related harm than drinking in others. However, they were conducted in countries culturally and legally different from European countries and were limited to cross-sectional designs. This study investigates the cross-sectional and longitudinal associations of alcohol-related harm with DVs in different locations in a sample of young Swiss men. A representative sample of 4536 young Swiss male drinkers completed baseline and 15-month follow-up questionnaires. These assessed DVs in 11 locations, alcohol-related harm (i.e. number of alcohol-related consequences and alcohol use disorder criteria) and frequency of RSOD. Cross-sectional and longitudinal associations of alcohol-related harm with DVs in each location were tested using regression models, with and without adjustment for frequency of RSOD. Both cross-sectional and longitudinal analyses showed significant positive associations between alcohol-related harm and DVs at friends' homes, in discos/nightclubs and in outdoor public places, when controlling for frequency of RSOD. In contrast, the contribution of DVs at one's own home and in restaurants was consistently not significant when adjusted for frequency of RSOD. When controlling for RSOD, associations between alcohol-related harm and DVs in bars/pubs, when playing sports, during other leisure activities, at cinemas/theatres, during sporting events, and during special events were not consistent between cross-sectional and longitudinal analyses. Results suggest that prevention interventions should not only target reducing the overall volume of alcohol consumed and the frequency of RSOD in general, but they should additionally focus on limiting alcohol consumption

  3. Reaching men who have sex with men: a comparison of respondent-driven sampling and time-location sampling in Guatemala City.

    PubMed

    Paz-Bailey, Gabriela; Miller, William; Shiraishi, Ray W; Jacobson, Jerry O; Abimbola, Taiwo O; Chen, Sanny Y

    2013-11-01

    We present a comparison of respondent-driven sampling (RDS) and time-location sampling (TLS) for behavioral surveillance studies among men who have sex with men (MSM). In 2010, we conducted two simultaneous studies using TLS (N = 609) and RDS (N = 507) in Guatemala city. Differences in characteristics of the population reached based on weighted estimates as well as the time and cost of recruitment are presented. RDS MSM were marginally more likely to self-report as heterosexual, less likely to disclose sexual orientation to family members and more likely to report sex with women than TLS MSM. Although RDS MSM were less likely than TLS MSM to report ≥2 non-commercial male partners, they were more likely to report selling sex in the past 12 months. The cost per participant was $89 and $121 for RDS and TLS, respectively. Our results suggest that RDS reached a more hidden sub-population of non-gay-identifying MSM than TLS and had a lower implementation cost.

  4. Spatial variability and source apportionment of PM2.5 across multiple sampling locations in southwest China

    NASA Astrophysics Data System (ADS)

    Shi, F.; Xie, S.

    2015-12-01

    The Chengdu Plain, which is located in the west of the Sichuan Basin, is the largest plain and the fastest-growing area in southwest China. The Chengdu Plain is considered one of the hotspot areas in China. The pollution pattern in this area is unique due to the hilly topography, humid and stagnant weather. To investigate the composition and major sources of the ambient PM2.5, a one-year observation was performed at five sites in the Chengdu Plain during August, 2013 to August, 2014. The five sites contained three urban background sites and two rural background sites. Samples were analyzed for major water-soluble ions, organic carbon (OC), element carbon (EC), and trace elements. The Positive Matrix Factorization (PMF) receptor model based on the combined data from five locations was applied to identify and quantify the likely sources. The annual mean mass concentration of PM2.5 in Chengdu Plain was 81 μg·m-3 with the maximum in winter and the minimum in summer. Eight main factors were identified for the PM2.5 fraction: vehicle emission, secondary nitrate, biomass burning and waste incineration emission, secondary sulfate, Mo-related manufacturing, fugitive dust, coal combustion and industry pollution. The five-site annual mean contributions of each source were 13%, 19%, 9%, 25%, 2%, 13%, 9% and 10%,respectively, to PM2.5, while exhibiting large spatial variability. The contribution of secondary sulfate to the PM2.5 mass was largest at all sites, indicating severe secondary pollution in the region. Biomass burning and waste incineration emission made larger proportion at rural sites than that of urban sites, while the vehicle emission was larger at urban sites. The Enrichment factors for Cd, Zn, Pb, As, Cu and Mo in PM2.5 were larger than 100 indicated that those elements were largely from anthropogenic origins. Cd, As and Cu can mainly originate from nonferrous metal industry, while Mo may mainly generated from ferromolybdenum and Mo powder manufacture. The

  5. Airborne Effluent Monitoring System Certification for New Canister Storage Building Ventilation Exhaust Stack

    SciTech Connect

    Glissmeyer, J.A.; Maughan, A.D.

    1999-04-01

    Pacific Northwest National Laboratory conducted three of the six tests needed to verify that the effluent monitoring system for the new Canister Storage Building ventilation exhaust stack meets applicable regulatory performance criteria for air sampling systems at nuclear facilities. These performance criteria address both the suitability of the location for the air-sampling probe and the transport of the sample to the collection devices. The criteria covering the location for the air-sampling probe ensure that the contaminants in the stack are well mixed with the airflow at the probe location such that the extracted sample represents the whole. The sample-transport criteria ensure that the sampled contaminants are quantitatively delivered to the collection device. The specific performance criteria are described in detail in this report. The tests reported here cover the contaminant tracer uniformity and particle delivery performance criteria. These criteria were successfully met. The other three tests were conducted by the start-up staff of Duke Engineering and Services Hanford Inc. (DESH) and reported elsewhere. The Canister Storage Building is located in the 200 East Area of the U.S. Department of Energy's Hanford Site near Richland, Washington. The new air-exhaust system was built under the W379 Project. The air sampling system features a probe with a single shrouded sampling nozzle, a sample delivery line, and a filter holder to collect the sample.

  6. Short protection device for stack of electrolytic cells

    DOEpatents

    Katz, Murray; Schroll, Craig R.

    1985-10-22

    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.

  7. Stack Characterization System Development and Testing

    SciTech Connect

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

    2011-01-01

    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.

  8. Stacks of Light

    NASA Image and Video Library

    2007-10-25

    These two images show tacked Chandra images for two different classes of distant, massive galaxy detected with NASA Spitzer. Image stacking is a procedure used to detect emission from objects that is too faint to be detected in single images.

  9. PAM stack test utility

    SciTech Connect

    Grondona, Mark A.

    2007-08-22

    The pamtest utility calls the normal PAM hooks using a service and username supplied on the command line. This allows an administratory to test any one of many configured PAM stacks as any existing user on the machine.

  10. Stacked Buoyant Payload Launcher

    DTIC Science & Technology

    2013-05-14

    reserved for undersea launched missiles. Underwater deployment of smaller payloads has been limited to ejection from torpedo tubes, the trash disposal...COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE Stacked Buoyant Payload Launcher 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...1 of 11 STACKED BUOYANT PAYLOAD LAUNCHER STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and

  11. A High Volume Stack Sampler

    NASA Technical Reports Server (NTRS)

    Boubel, Richard W.

    1971-01-01

    The stack sampler described in this paper has been developed to overcome the difficulties of particulate sampling with presently available equipment. Its use on emissions from hog fuel fired boilers, back-fired incinerators, wigwam burners, asphalt plants, and seed cleaning cyclones is reported. The results indicate that the sampler is rapid and reliable in its use. It is relatively simple and inexpensive to operate. For most sources it should be considered over the more complicated and expensive sampling trains being used and specified.

  12. A High Volume Stack Sampler

    NASA Technical Reports Server (NTRS)

    Boubel, Richard W.

    1971-01-01

    The stack sampler described in this paper has been developed to overcome the difficulties of particulate sampling with presently available equipment. Its use on emissions from hog fuel fired boilers, back-fired incinerators, wigwam burners, asphalt plants, and seed cleaning cyclones is reported. The results indicate that the sampler is rapid and reliable in its use. It is relatively simple and inexpensive to operate. For most sources it should be considered over the more complicated and expensive sampling trains being used and specified.

  13. Capillary electrophoresis with online stacking in combination with AgNPs@MCM-41 reinforced hollow fiber solid-liquid phase microextraction for quantitative analysis of Capecitabine and its main metabolite 5-Fluorouracil in plasma samples isolated from cancer patients.

    PubMed

    Forough, Mehrdad; Farhadi, Khalil; Molaei, Rahim; Khalili, Hedayat; Shakeri, Ramin; Zamani, Asghar; Matin, Amir Abbas

    2017-01-01

    The purpose of this study is the development and validation of a simple, novel, selective and fast off-line microextraction technique combining capillary electrophoresis with in-column field-amplified sample injection (FASI) for the simultaneous determination of capecitabine (CAP) and its active metabolite, 5-Fluorouracil (5-FU), in human plasma. At the moment, there is a lack of using cost-effective CE tool combined with novel miniaturized sample clean-up techniques for analysis of these important anti-cancer agents in plasma samples. This paper intends to fill this gap and describe a simple off-line sample pretreatment by means of AgNPs@MCM-41 reinforced hollow fiber Solid/Liquid phase microextraction (AgNPs@MCM41-HF-SLPME) with subsequent quantitation by FASI-CE. The separation of analytes was performed using a BGE containing 60mM phosphate-Tris buffer (pH 7) with 10% methanol as an organic modifier. Before sample loading, a short water plug (50mbar, 3s) was injected to permit FASI for stacking. Various parameters affecting the off-line microextraction efficiency as well as FASI were optimized. Migration time was found to be 6.6 (±0.1)min for 5-FU and 7.4 (±0.2)min for CAP. The linearity, precision, accuracy, recovery, selectivity, specificity, stability as well as the robustness of the method was evaluated from spiked plasma samples during the course of validation. The results revealed that the presented technique demonstrates acceptable accuracy and precision, miniaturized sample preparation and a reduced need for complicated equipment along with an acceptable analysis time. The validated method was successfully applied to determine CAP and 5-FU in patient's plasma samples.

  14. Evaluation of Airborne Particulate Matter and Metals Data in Personal, Indoor and Outdoor Environments using ED-XRF and ICP-MS and Co-located Duplicate Samples

    EPA Science Inventory

    Factors and sources affecting measurement uncertainty in airborne particulate matter (PM) gravimetric measurements and elemental analyses were investigated as part of the Windsor Ontario Exposure Assessment Study (WOEAS). The assessment was made using co-located duplicate sample...

  15. Evaluation of Airborne Particulate Matter and Metals Data in Personal, Indoor and Outdoor Environments using ED-XRF and ICP-MS and Co-located Duplicate Samples

    EPA Science Inventory

    Factors and sources affecting measurement uncertainty in airborne particulate matter (PM) gravimetric measurements and elemental analyses were investigated as part of the Windsor Ontario Exposure Assessment Study (WOEAS). The assessment was made using co-located duplicate sample...

  16. Technical description of Stack 296-B-5

    SciTech Connect

    Ridge, T.M.

    1994-11-15

    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).

  17. Stacked antiaromatic porphyrins

    PubMed Central

    Nozawa, Ryo; Tanaka, Hiroko; Cha, Won-Young; Hong, Yongseok; Hisaki, Ichiro; Shimizu, Soji; Shin, Ji-Young; Kowalczyk, Tim; Irle, Stephan; Kim, Dongho; Shinokubo, Hiroshi

    2016-01-01

    Aromaticity is a key concept in organic chemistry. Even though this concept has already been theoretically extrapolated to three dimensions, it usually still remains restricted to planar molecules in organic chemistry textbooks. Stacking of antiaromatic π-systems has been proposed to induce three-dimensional aromaticity as a result of strong frontier orbital interactions. However, experimental evidence to support this prediction still remains elusive so far. Here we report that close stacking of antiaromatic porphyrins diminishes their inherent antiaromaticity in the solid state as well as in solution. The antiaromatic stacking furthermore allows a delocalization of the π-electrons, which enhances the two-photon absorption cross-section values of the antiaromatic porphyrins. This feature enables the dynamic switching of the non-linear optical properties by controlling the arrangement of antiaromatic π-systems on the basis of intermolecular orbital interactions. PMID:27901014

  18. Stacked antiaromatic porphyrins

    NASA Astrophysics Data System (ADS)

    Nozawa, Ryo; Tanaka, Hiroko; Cha, Won-Young; Hong, Yongseok; Hisaki, Ichiro; Shimizu, Soji; Shin, Ji-Young; Kowalczyk, Tim; Irle, Stephan; Kim, Dongho; Shinokubo, Hiroshi

    2016-11-01

    Aromaticity is a key concept in organic chemistry. Even though this concept has already been theoretically extrapolated to three dimensions, it usually still remains restricted to planar molecules in organic chemistry textbooks. Stacking of antiaromatic π-systems has been proposed to induce three-dimensional aromaticity as a result of strong frontier orbital interactions. However, experimental evidence to support this prediction still remains elusive so far. Here we report that close stacking of antiaromatic porphyrins diminishes their inherent antiaromaticity in the solid state as well as in solution. The antiaromatic stacking furthermore allows a delocalization of the π-electrons, which enhances the two-photon absorption cross-section values of the antiaromatic porphyrins. This feature enables the dynamic switching of the non-linear optical properties by controlling the arrangement of antiaromatic π-systems on the basis of intermolecular orbital interactions.

  19. 49 CFR 178.606 - Stacking test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR PACKAGINGS Testing of Non-bulk.... (c) Test method—(1) Design qualification testing. The test sample must be subjected to a force... might be stacked on it during transport; where the contents of the test sample are non-hazardous liquids...

  20. Laser pulse stacking method

    DOEpatents

    Moses, Edward I.

    1992-01-01

    A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter.

  1. Laser pulse stacking method

    DOEpatents

    Moses, E.I.

    1992-12-01

    A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter. 2 figs.

  2. Determination of urinary nucleosides via borate complexation capillary electrophoresis combined with dynamic pH junction-sweeping-large volume sample stacking as three sequential steps for their on-line enrichment.

    PubMed

    Rageh, Azza H; Kaltz, Achim; Pyell, Ute

    2014-09-01

    The combination of dynamic pH junction, sweeping (using borate complexation), and large volume sample stacking (LVSS) is investigated as three consecutive steps for on-line focusing in the sensitive quantitation of urinary nucleosides by CE-UVD. A low conductivity aqueous sample matrix free from borate and a high conductivity BGE (containing borate, pH 9.25) are needed to fulfill the required conditions for dynamic pH junction, LVSS, and sweeping. Parameters affecting the separation and the enrichment efficiency are studied such as buffer concentration, separation voltage, capillary temperature, sample composition, and sample injection volume. Prerequisite for the developed strategy is the extraction of the nucleosides from urine using a phenylboronate affinity gel, which is described to be a unique means for the selective enrichment of cis-diol metabolites under alkaline conditions. The impact of ionic constituents remaining in the eluate after extraction on focusing efficiency and resolution is investigated. The developed method is applied to the analysis of blank and spiked urine samples. Fundamental aspects underlying the proposed enrichment procedure are discussed. A detection limit as low as 10 ng mL(-1) is achieved. To the best of our knowledge, this LOD represents the lowest LOD reported so far for the analysis of nucleosides using CE with UV detection and provides a comparable sensitivity to CE/MS. Because of the high sensitivity, the proposed method shows a great potential for the analysis of nucleosides in human urine and other types of biological fluids.

  3. Completeness and Reliability of Location Data Collected on the Web: Assessing the Quality of Self-Reported Locations in an Internet Sample of Men Who Have Sex With Men

    PubMed Central

    Kramer, Michael R; Cooper, Hannah LF; Rosenberg, Eli S; Sullivan, Patrick S

    2016-01-01

    were less likely to indicate the location of that sex (prevalence ratio, 0.8; 95% CI, 0.7-1.0). Overall, 83% of participants placed their home’s location within the boundaries of their reported residential ZIP code. Of locations having a specific text description, the median distance between the participant-selected location and the location determined using the specific text description was 0.29 miles (25th and 75th percentiles, 0.06-0.88). Conclusions Using this Web-based map tool, this Web-based sample of MSM was generally willing and able to provide accurate data regarding both home and nonresidential locations. This tool provides a mechanism to collect data that can be used in more nuanced studies of place and sexual risk and preventive behaviors of MSM. PMID:27283957

  4. Sampling and analysis plan for sludge located in fuel storage canisters of the 105-K West basin

    SciTech Connect

    Baker, R.B.

    1997-04-30

    This Sampling and Analysis Plan (SAP) provides direction for the first sampling of sludge from the K West Basin spent fuel canisters. The specially developed sampling equipment removes representative samples of sludge while maintaining the radioactive sample underwater in the basin pool (equipment is described in WHC-SD-SNF-SDD-004). Included are the basic background logic for sample selection, the overall laboratory analyses required and the laboratory reporting required. These are based on requirements put forth in the data quality objectives (WHC-SD-SNF-DQO-012) established for this sampling and characterization activity.

  5. Sampling and analysis plan for sludge located in fuel storage canisters of the 105-K east basin

    SciTech Connect

    Baker, R.B., Westinghouse Hanford

    1996-05-20

    This Sampling and Analysis Plan (SAP) provides direction for the first sampling of sludge from the K East Basin spent fuel canisters. The specially developed sampling equipment used removes representative samples of sludge while maintaining the radioactive sample underwater in the basin pool (equipment is described in WHC-SD-SNF-SDD-004). Included are the basic background logic for sample selection, the overall laboratory analyses required and the laboratory reporting required. These are based on requirements put forth in the data quality objectives (WHC-SD-SNF-DQO-008) established for this sampling and characterization activity.

  6. Measuring Structural Parameters Through Stacking Galaxy Images

    NASA Astrophysics Data System (ADS)

    Li, Yubin; Zheng, Xian Zhong; Gu, Qiu-Sheng; Wang, Yi-Peng; Wen, Zhang Zheng; Guo, Kexin; An, Fang Xia

    2016-12-01

    It remains challenging to detect the low surface brightness structures of faint high-z galaxies, which are key to understanding the structural evolution of galaxies. The technique of image stacking allows us to measure the averaged light profile beneath the detection limit and probe the extended structure of a group of galaxies. We carry out simulations to examine the recovery of the averaged surface brightness profile through stacking model Hubble Space Telescope/Advanced Camera for Surveys images of a set of galaxies as functions of the Sérsic index (n), effective radius (R e) and axis ratio (AR). The Sérsic profile best fitting the radial profile of the stacked image is taken as the recovered profile, in comparison with the intrinsic mean profile of the model galaxies. Our results show that, in general, the structural parameters of the mean profile can be properly determined through stacking, though systematic biases need to be corrected when spreads of R e and AR are counted. We find that the Sérsic index is slightly overestimated and R e is underestimated at {AR}\\lt 0.5 because the stacked image appears to be more compact due to the presence of inclined galaxies; the spread of R e biases the stacked profile to have a higher Sérsic index. We stress that the measurements of structural parameters through stacking should take these biases into account. We estimate the biases in the recovered structural parameters from stacks of galaxies when the samples have distributions of {R}{{e}}, AR and n seen in local galaxies.

  7. Gene stacking by recombinases

    USDA-ARS?s Scientific Manuscript database

    Efficient methods of stacking genes into plant genomes are needed to expedite transfer of multigenic traits into diverse crops grown in a variety of environments. Over two decades of research has identified several site-specific recombinases that carry out efficient cis and trans recombination betw...

  8. Stacked Sequential Learning

    DTIC Science & Technology

    2005-07-01

    a constant factor of K + 2. (To see this, note sequential stacking requires training K+2 classifiers: the classifiers f1, . . . , fK used in cross...on the non- sequential learners (ME and VP) but improves per- formance of the sequential learners (CRFs and VPH - MMs) less consistently. This pattern

  9. 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

  10. 23. Brick coke quencher, brick stack, metal stack to right, ...

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

    23. Brick coke quencher, brick stack, metal stack to right, coke gas pipe to left; in background, BOF building, limestone piles, Levy's Slag Dump. Looking north/northwest - Rouge Steel Company, 3001 Miller Road, Dearborn, MI

  11. Electrochemical Detection in Stacked Paper Networks.

    PubMed

    Liu, Xiyuan; Lillehoj, Peter B

    2015-08-01

    Paper-based electrochemical biosensors are a promising technology that enables rapid, quantitative measurements on an inexpensive platform. However, the control of liquids in paper networks is generally limited to a single sample delivery step. Here, we propose a simple method to automate the loading and delivery of liquid samples to sensing electrodes on paper networks by stacking multiple layers of paper. Using these stacked paper devices (SPDs), we demonstrate a unique strategy to fully immerse planar electrodes by aqueous liquids via capillary flow. Amperometric measurements of xanthine oxidase revealed that electrochemical sensors on four-layer SPDs generated detection signals up to 75% higher compared with those on single-layer paper devices. Furthermore, measurements could be performed with minimal user involvement and completed within 30 min. Due to its simplicity, enhanced automation, and capability for quantitative measurements, stacked paper electrochemical biosensors can be useful tools for point-of-care testing in resource-limited settings.

  12. 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

  13. 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

  14. Modeling the Air Flow in the 3410 Building Filtered Exhaust Stack System

    SciTech Connect

    Recknagle, Kurtis P.; Barnett, J. Matthew; Suffield, Sarah R.

    2013-01-23

    Additional ventilation capacity has been designed for the 3410 Building filtered exhaust stack system. The updated system will increase the number of fans from two to three and will include ductwork to incorporate the new fan into the existing stack. Stack operations will involve running various two-fan combinations at any given time. The air monitoring system of the existing two-fan stack was previously found to be in compliance with the ANSI/HPS N13.1-1999 standard, however it is not known if the modified (three-fan) system will comply. Subsequently, a full-scale three-dimensional (3-D) computational fluid dynamics (CFD) model of the modified stack system has been created to examine the sampling location for compliance with the standard. The CFD modeling results show good agreement with testing data collected from the existing 3410 Building stack and suggest that velocity uniformity and flow angles will remain well within acceptance criteria when the third fan and associated ductwork is installed. This includes two-fan flow rates up to 31,840 cfm for any of the two-fan combinations. For simulation cases in which tracer gas and particles are introduced in the main duct, the model predicts that both particle and tracer gas coefficients of variance (COVs) may be larger than the acceptable 20 percent criterion of the ANSI/HPS N13.1-1999 standard for each of the two-fan, 31,840 cfm combinations. Simulations in which the tracers are introduced near the fans result in improved, though marginally acceptable, COV values for the tracers. Due to the remaining uncertainty that the stack will qualify with the addition of the third fan and high flow rates, a stationary air blender from Blender Products, Inc. is considered for inclusion in the stack system. A model of the air blender has been developed and incorporated into the CFD model. Simulation results from the CFD model that includes the air blender show striking improvements in tracer gas mixing and tracer particle

  15. 40 CFR 61.53 - Stack sampling.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... (c) Mercury chlor-alkali plants—cell room ventilation system. (1) Stationary sources using mercury... the Administrator, for a minimum of 2 years. (b) Mercury chlor-alkali plant—hydrogen and end-box... operator employing mercury chlor-alkali cell(s) shall test emissions from hydrogen streams according...

  16. 40 CFR 61.53 - Stack sampling.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... (c) Mercury chlor-alkali plants—cell room ventilation system. (1) Stationary sources using mercury... the Administrator, for a minimum of 2 years. (b) Mercury chlor-alkali plant—hydrogen and end-box... operator employing mercury chlor-alkali cell(s) shall test emissions from hydrogen streams according...

  17. 40 CFR 61.53 - Stack sampling.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... (c) Mercury chlor-alkali plants—cell room ventilation system. (1) Stationary sources using mercury... the Administrator, for a minimum of 2 years. (b) Mercury chlor-alkali plant—hydrogen and end-box... operator employing mercury chlor-alkali cell(s) shall test emissions from hydrogen streams according...

  18. 40 CFR 61.53 - Stack sampling.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... (c) Mercury chlor-alkali plants—cell room ventilation system. (1) Stationary sources using mercury... the Administrator, for a minimum of 2 years. (b) Mercury chlor-alkali plant—hydrogen and end-box... operator employing mercury chlor-alkali cell(s) shall test emissions from hydrogen streams according...

  19. 40 CFR 61.53 - Stack sampling.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the effective date in the case of an existing source or a new source which has an initial start-up date preceding the effective date; or (ii) Within 90 days of startup in the case of a new source which did not have an initial startup date preceding the effective date. (2) The Administrator shall...

  20. Coupling geostatistical approaches with PCA and fuzzy optimal model (FOM) for the integrated assessment of sampling locations of water quality monitoring networks (WQMNs).

    PubMed

    Ou, Chunping; St-Hilaire, André; Ouarda, Taha B M J; Conly, F Malcolm; Armstrong, Nicole; Khalil, Bahaa; Proulx-McInnis, Sandra

    2012-12-01

    The assessment of the adequacy of sampling locations is an important aspect in the validation of an effective and efficient water quality monitoring network. Two geostatistical approaches (e.g., kriging and Moran's I) are presented to assess multiple sampling locations. A flexible and comprehensive framework was developed for the selection of multiple sampling locations of multiple variables which was accomplished by coupling geostatistical approaches with principal component analysis (PCA) and fuzzy optimal model (FOM). The FOM was used in the integrated assessment of both multiple principal components and multiple geostatistical approaches. These integrated methods were successfully applied to the assessment of two independent water quality monitoring networks (WQMNs) of Lake Winnipeg, Canada, which respectively included 14 and 30 stations from 2006 to 2010.

  1. Sampling and analysis plan for sludge located on the floor and in the pits of the 105-K basins

    SciTech Connect

    BAKER, R.B.

    1998-11-20

    This Sampling and Analysis Plan (SAP) provides direction for the sampling of the sludge found on the floor and in the remote pits of the 105-K Basins to provide: (1) basic data for the sludges that have not been characterized to-date and (2) representative Sludge material for process tests to be made by the SNF Project/K Basins sludge treatment process subproject. The sampling equipment developed will remove representative samples of the radioactive sludge from underwater at the K Basins, depositing them in shielded containers for transport to the Hanford Site laboratories. Included in the present document is the basic background logic for selection of the samples to meet the requirements established in the Data Quality Objectives (DQO), HNF-2033, for this sampling activity. The present document also includes the laboratory analyses, methods, procedures, and reporting that will be required to meet the DQO.

  2. Reinforcer Control by Comparison-Stimulus Color and Location in a Delayed Matching-to-Sample Task

    ERIC Educational Resources Information Center

    Alsop, Brent; Jones, B. Max

    2008-01-01

    Six pigeons were trained in a delayed matching-to-sample task involving bright- and dim-yellow samples on a central key, a five-peck response requirement to either sample, a constant 1.5-s delay, and the presentation of comparison stimuli composed of red on the left key and green on the right key or vice versa. Green-key responses were…

  3. Reinforcer Control by Comparison-Stimulus Color and Location in a Delayed Matching-to-Sample Task

    ERIC Educational Resources Information Center

    Alsop, Brent; Jones, B. Max

    2008-01-01

    Six pigeons were trained in a delayed matching-to-sample task involving bright- and dim-yellow samples on a central key, a five-peck response requirement to either sample, a constant 1.5-s delay, and the presentation of comparison stimuli composed of red on the left key and green on the right key or vice versa. Green-key responses were…

  4. β-Cyclodextrin enhanced on-line organic solvent field-amplified sample stacking in capillary zone electrophoresis for analysis of ambroxol in human plasma, following liquid-liquid extraction in the 96-well format.

    PubMed

    Li, Ji; Bi, Youwei; Wang, Li; Sun, Fanlu; Chen, Zhao; Xu, Guili; Fan, Guorong

    2012-07-01

    A field-amplified sample stacking (FASS) and capillary zone electrophoresis (CZE) method is described for the quantification of ambroxol hydrochloride in human plasma, following liquid-liquid extraction in the 96-well format. The separation was carried out at 25 °C in a 31.2 cm × 75 μm fused-silica capillary with an applied voltage of 15 kV. The background electrolyte (BGE) was composed of 6.25 mM borate-25 mM phosphate (pH 3.0) and 1mM β-cyclodextrin. The detection wavelength was 210 nm. Clean-up and preconcentration of plasma biosamples were developed by 96-well format liquid-liquid extraction (LLE). In this study, FASS in combination with β-cyclodextrin enhanced the sensitivity about 60-70 fold in total. The method was suitably validated with respect to stability, specificity, linearity, lower limit of quantitation, accuracy, precision, extraction recovery and robustness. The calibration graph was linear for ambroxol hydrochloride from 2 to 500 ng/ml. The lower limit of quantification was 2 ng/ml. The intra- and inter-day precisions of lowest limit of quantification (LLOQ) were 9.61 and 11.80%, respectively. The method developed was successfully applied to the evaluation of clinical pharmacokinetic study of ambroxol hydrochloride tablet after oral administration to 12 healthy volunteers. Copyright © 2012. Published by Elsevier B.V.

  5. Energy Expenditure of Sport Stacking

    ERIC Educational Resources Information Center

    Murray, Steven R.; Udermann, Brian E.; Reineke, David M.; Battista, Rebecca A.

    2009-01-01

    Sport stacking is an activity taught in many physical education programs. The activity, although very popular, has been studied minimally, and the energy expenditure for sport stacking is unknown. Therefore, the purposes of this study were to determine the energy expenditure of sport stacking in elementary school children and to compare that value…

  6. Energy Expenditure of Sport Stacking

    ERIC Educational Resources Information Center

    Murray, Steven R.; Udermann, Brian E.; Reineke, David M.; Battista, Rebecca A.

    2009-01-01

    Sport stacking is an activity taught in many physical education programs. The activity, although very popular, has been studied minimally, and the energy expenditure for sport stacking is unknown. Therefore, the purposes of this study were to determine the energy expenditure of sport stacking in elementary school children and to compare that value…

  7. A Review of Advancements in Particulate Matter Sampling and Analysis and its Application to Identifying Source Impacts at Receptor Locations

    EPA Science Inventory

    Time-integrated (typically 24-hr) filter-based methods (historical methods) form the underpinning of our understanding of the fate, impact of source emissions at receptor locations (source impacts), and potential health and welfare effects of particulate matter (PM) in air. Over...

  8. A Review of Advancements in Particulate Matter Sampling and Analysis and its Application to Identifying Source Impacts at Receptor Locations

    EPA Science Inventory

    Time-integrated (typically 24-hr) filter-based methods (historical methods) form the underpinning of our understanding of the fate, impact of source emissions at receptor locations (source impacts), and potential health and welfare effects of particulate matter (PM) in air. Over...

  9. Fuel Cell Stacks

    DTIC Science & Technology

    1975-04-01

    AD-A009 587 FUEL CELL STACKS Bernard S. Baker Energy Research Corporation Prepared for: Army Mobility Equipment Research and Development Center April... Mobility Equipment Research and Development Center Unclassified For- Belvoir, Virginia 22060 [15. DE.CLASSIFICATION/L.TWNOGRADING SCREOUJLE 16...the majority of effort has been directed at translating technoilogy for small comn- ponent manufacture on a laboratory scale into large size components

  10. Iridium Interfacial Stack (IRIS)

    NASA Technical Reports Server (NTRS)

    Spry, David James (Inventor)

    2015-01-01

    An iridium interfacial stack ("IrIS") and a method for producing the same are provided. The IrIS may include ordered layers of TaSi.sub.2, platinum, iridium, and platinum, and may be placed on top of a titanium layer and a silicon carbide layer. The IrIS may prevent, reduce, or mitigate against diffusion of elements such as oxygen, platinum, and gold through at least some of its layers.

  11. High Resolution Mass Spectrometry of Seasonal Aerosol Samples From an Urban Location in the Italian Po Valley

    NASA Astrophysics Data System (ADS)

    Mahon, Brendan; Giorio, Chiara; Gallimore, Peter J.; Zielinski, Arthur T.; Tapparo, Andrea; Kalberer, Markus

    2016-04-01

    The Po Valley in Northern Italy represents one of the most polluted environments in Europe, with PM2.5 and ozone concentrations regularly exceeding 100μg/m3 and 50ppb respectively. Particularly during winter, prolonged inversion conditions together with biomass burning and anthropogenic emissions regularly lead to severe air pollution events. Over the course of several months in 2013-14, we carried out a sampling program at a city-centre site in Padova, Italy, collecting 24-hour high-volume aerosol filter samples, 18 in winter (mid December - mid March) and 20 in summer (late May - late July). Utilising high-resolution Orbitrap mass spectrometry techniques, we have characterised these sample sets to examine the long-term variation in aerosol composition over the sampling campaign and to determine the effect of anthropogenic gaseous pollutants such as NOx and SO2 on the composition of organic particle components. The results showed that between ca. 450-700 ions were measured in each sample in both the summer and winter sample sets, however the majority (90%) of ions in the winter samples were below 300m/z and below 380m/z in the summer samples. A much higher percentage of CHO-only ions were found in winter (ca. 27%) compared to the summer samples (ca. 6%), indicating a higher degree of photochemical reactions taking place involving pollutants such as NOx and SO2 in summer. Our results represent the first long term data set of high-resolution measurements of aerosol composition and demonstrate that this technique is an important tool in evaluating the composition of aerosol particles in complex polluted urban areas.

  12. Performance of Composites from 3D Orthogonal Woven Preforms in terms of Architecture and Sample Location during Resin Infusion

    NASA Astrophysics Data System (ADS)

    Ince, Mehmet Erdem

    error. In VIP, presence of flexible vacuum bag on one side of the molding and pressure gradient from resin inlet to flow front change the compaction pressure on unsaturated preform that results in thickness and FVF variation in cured composite. Previous work on composite using VIP dealt with resin flow modeling to predict thickness, FVF, and resin pressure profiles. However, the effect of these profiles on mechanical properties was not investigated. In this study, specimens from composite panels were tracked in terms of their positions relative to resin inlet. Analytical (thickness, FVF, and void content) and mechanical (tensile, three-point flexure, and impact) properties of the specimens were measured to investigate the effect of specimen location on composite dimension and performance. Additionally, vacuum (75 and 100 kPa levels) was considered as variable to investigate its effect on composite formation and performance. Effect of fabric architecture on resin infusion performance was demonstrated by faster mold filling times of preforms with plain and basket weaves due to their straight, uniform, and wide resin flow channels compared to tortuous channels in preforms with twill weaves. Analytical properties of 3D orthogonal woven glass fiber composites showed parallel result with previous VIP researches such as thickness decreased, FVF increased and void content fluctuated from resin inlet to outlet. Slight increase from resin inlet to outlet was observed for the tensile properties in x- and y-directions. Due to their higher FVF compared to the composites with other two weaves, composites with twill weaves resulted in better mechanical properties. Increase in x-yarn density caused increase in tensile stress in x-direction, whereas it resulted in reduction in tensile properties in y-direction. Increase in vacuum pressure slightly improved tensile stress in both directions. Peak tensile stress in y-direction of three layers, 5.48 x-yarns/layer/cm balanced (defined as

  13. Using Tax Parcels to Select a Location-Based Sample: An Illustration that Examines Residents' Awareness of Sex Offenders in Neighborhoods

    ERIC Educational Resources Information Center

    Craun, Sarah W.; Freisthler, Bridget

    2008-01-01

    Social science research is increasingly considering place when examining social programs and policies with a spatial component. A specific research challenge involving spatial policies is how to select a sample of individuals based on their geographic locations. This article illustrates the use of geographic information systems, tax parcels, and…

  14. Assessment of water quality index of bore well water samples from some selected locations of South Gujarat, India.

    PubMed

    Tripathi, S; Patel, H M; Srivastava, P K; Bafna, A M

    2013-10-01

    The present study calculates the water quality index (WQI) of some selected sites from South Gujarat (India) and assesses the impact of industries, agriculture and human activities. Chemical parameters were monitored for the calculation of WQI of some selected bore well samples. The results revealed that the WQI of the some bore well samples exceeded acceptable levels due to the dumping of wastes from municipal, industrial and domestic sources and agricultural runoff as well. Inverse Distance Weighting (IDW) was implemented for interpolation of each water quality parameter (pH, EC, alkalinity, total hardness, chloride, nitrate and sulphate) for the entire sampled area. The bore water is unsuitable for drinking and if the present state of affairs continues for long, it may soon become an ecologically dead bore.

  15. An efficient reliability algorithm for locating design point using the combination of importance sampling concepts and response surface method

    NASA Astrophysics Data System (ADS)

    Shayanfar, Mohsen Ali; Barkhordari, Mohammad Ali; Roudak, Mohammad Amin

    2017-06-01

    Monte Carlo simulation (MCS) is a useful tool for computation of probability of failure in reliability analysis. However, the large number of required random samples makes it time-consuming. Response surface method (RSM) is another common method in reliability analysis. Although RSM is widely used for its simplicity, it cannot be trusted in highly nonlinear problems due to its linear nature. In this paper, a new efficient algorithm, employing the combination of importance sampling, as a class of MCS, and RSM is proposed. In the proposed algorithm, analysis starts with importance sampling concepts and using a represented two-step updating rule of design point. This part finishes after a small number of samples are generated. Then RSM starts to work using Bucher experimental design, with the last design point and a represented effective length as the center point and radius of Bucher's approach, respectively. Through illustrative numerical examples, simplicity and efficiency of the proposed algorithm and the effectiveness of the represented rules are shown.

  16. Distribution of Foraminifera in the Core Samples of Kollidam and Marakanam Mangrove Locations, Tamil Nadu, Southeast Coast of India

    NASA Astrophysics Data System (ADS)

    Nowshath, M.

    2013-05-01

    In order to study the distribution of Foraminifera in the subsurface sediments of mangrove environment, two core samples have been collected i) near boating house, Pitchavaram, from Kollidam estuary (C2) and ii) backwaters of Marakanam (C2)with the help of PVC corer. The length of the core varies from a total of 25 samples from both cores were obtained and they were subjected to standard micropaleontological and sedimentological analyses for the evaluation of different sediment characteristics. The core sample No.C1 (Pitchavaram) yielded only foraminifera whereas the other one core no.C2 (Marakanam) has yielded discussed only the down core distribution of foraminifera. The widely utilized classification proposed by Loeblich and Tappan (1987) has been followed in the present study for Foraminiferal taxonomy and accordingly 23 foraminiferal species belonging to 18 genera, 10 families, 8 superfamilies and 4 suborders have been reported and illustrated. The foraminiferal species recorded are characteristic of shallow innershelf to marginal marine and tropical in nature. Sedimentological parameters such as CaCO3, Organic matter and sand-silt-clay ratio was estimated and their down core distribution is discussed. An attempt has been made to evaluate the favourable substrate for the Foraminifera population abundance in the present area of study. From the overall distribution of foraminifera in different samples of Kollidam estuary (Pitchavaram area), and Marakanam estuary it is observed that siltysand and sandysilt are more accommodative substrate for the population of foraminifera, respectively. The distribution of foraminifera in the core samples indicate that the sediments were deposited under normal oxygenated environment conditions.;

  17. Electrolyte matrix in a molten carbonate fuel cell stack

    DOEpatents

    Reiser, Carl A.; Maricle, Donald L.

    1987-04-21

    A fuel cell stack is disclosed with modified electrolyte matrices for limiting the electrolytic pumping and electrolyte migration along the stack external surfaces. Each of the matrices includes marginal portions at the stack face of substantially greater pore size than that of the central body of the matrix. Consequently, these marginal portions have insufficient electrolyte fill to support pumping or wicking of electrolyte from the center of the stack of the face surfaces in contact with the vertical seals. Various configurations of the marginal portions include a complete perimeter, opposite edge portions corresponding to the air plenums and tab size portions corresponding to the manifold seal locations. These margins will substantially limit the migration of electrolyte to and along the porous manifold seals during operation of the electrochemical cell stack.

  18. Electrolyte matrix in a molten carbonate fuel cell stack

    DOEpatents

    Reiser, C.A.; Maricle, D.L.

    1987-04-21

    A fuel cell stack is disclosed with modified electrolyte matrices for limiting the electrolytic pumping and electrolyte migration along the stack external surfaces. Each of the matrices includes marginal portions at the stack face of substantially greater pore size than that of the central body of the matrix. Consequently, these marginal portions have insufficient electrolyte fill to support pumping or wicking of electrolyte from the center of the stack of the face surfaces in contact with the vertical seals. Various configurations of the marginal portions include a complete perimeter, opposite edge portions corresponding to the air plenums and tab size portions corresponding to the manifold seal locations. These margins will substantially limit the migration of electrolyte to and along the porous manifold seals during operation of the electrochemical cell stack. 6 figs.

  19. [Strategies for biobank networks. Classification of different approaches for locating samples and an outlook on the future within the BBMRI-ERIC].

    PubMed

    Lablans, Martin; Kadioglu, Dennis; Mate, Sebastian; Leb, Ines; Prokosch, Hans-Ulrich; Ückert, Frank

    2016-03-01

    Medical research projects often require more biological material than can be supplied by a single biobank. For this reason, a multitude of strategies support locating potential research partners with matching material without requiring centralization of sample storage. Classification of different strategies for biobank networks, in particular for locating suitable samples. Description of an IT infrastructure combining these strategies. Existing strategies can be classified according to three criteria: (a) granularity of sample data: coarse bank-level data (catalogue) vs. fine-granular sample-level data, (b) location of sample data: central (central search service) vs. decentral storage (federated search services), and (c) level of automation: automatic (query-based, federated search service) vs. semi-automatic (inquiry-based, decentral search). All mentioned search services require data integration. Metadata help to overcome semantic heterogeneity. The "Common Service IT" in BBMRI-ERIC (Biobanking and BioMolecular Resources Research Infrastructure) unites a catalogue, the decentral search and metadata in an integrated platform. As a result, researchers receive versatile tools to search suitable biomaterial, while biobanks retain a high degree of data sovereignty. Despite their differences, the presented strategies for biobank networks do not rule each other out but can complement and even benefit from each other.

  20. Assessment of the Proposed INTEC CPP 666 Stack Monitoring Site for Compliance with ANSI/HPS N13.1 1999

    SciTech Connect

    Glissmeyer, John A.; Flaherty, Julia E.

    2010-02-16

    This document reports on a series of tests to determine whether the proposed new location for air sampling probes in the CPP-666 heating, ventilation and air conditioning (HVAC) exhaust duct would meet the applicable regulatory criteria regarding the placement of an air sampling probe. Federal regulations( ) require that a sampling probe be located in the exhaust stack according to the criteria of the American National Standards Institute/Health Physical Society (ANSI/HPS) N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities. These criteria address the capability of the sampling probe to extract a sample that is representative of the effluent stream.

  1. Stacked Extreme Learning Machines.

    PubMed

    Zhou, Hongming; Huang, Guang-Bin; Lin, Zhiping; Wang, Han; Soh, Yeng Chai

    2015-09-01

    Extreme learning machine (ELM) has recently attracted many researchers' interest due to its very fast learning speed, good generalization ability, and ease of implementation. It provides a unified solution that can be used directly to solve regression, binary, and multiclass classification problems. In this paper, we propose a stacked ELMs (S-ELMs) that is specially designed for solving large and complex data problems. The S-ELMs divides a single large ELM network into multiple stacked small ELMs which are serially connected. The S-ELMs can approximate a very large ELM network with small memory requirement. To further improve the testing accuracy on big data problems, the ELM autoencoder can be implemented during each iteration of the S-ELMs algorithm. The simulation results show that the S-ELMs even with random hidden nodes can achieve similar testing accuracy to support vector machine (SVM) while having low memory requirements. With the help of ELM autoencoder, the S-ELMs can achieve much better testing accuracy than SVM and slightly better accuracy than deep belief network (DBN) with much faster training speed.

  2. Asymmetric Flexible Supercapacitor Stack

    NASA Astrophysics Data System (ADS)

    Leela Mohana Reddy, A.; Estaline Amitha, F.; Jafri, Imran; Ramaprabhu, S.

    2008-04-01

    Electrical double layer supercapacitor is very significant in the field of electrical energy storage which can be the solution for the current revolution in the electronic devices like mobile phones, camera flashes which needs flexible and miniaturized energy storage device with all non-aqueous components. The multiwalled carbon nanotubes (MWNTs) have been synthesized by catalytic chemical vapor deposition technique over hydrogen decrepitated Mischmetal (Mm) based AB3 alloy hydride. The polymer dispersed MWNTs have been obtained by insitu polymerization and the metal oxide/MWNTs were synthesized by sol-gel method. Morphological characterizations of polymer dispersed MWNTs have been carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM and HRTEM). An assymetric double supercapacitor stack has been fabricated using polymer/MWNTs and metal oxide/MWNTs coated over flexible carbon fabric as electrodes and nafion® membrane as a solid electrolyte. Electrochemical performance of the supercapacitor stack has been investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.

  3. Effect of diet, location and sampling year on bioaccumulation of mercury, selenium and cadmium in pelagic feeding seabirds in Svalbard.

    PubMed

    Øverjordet, Ida Beathe; Gabrielsen, Geir Wing; Berg, Torunn; Ruus, Anders; Evenset, Anita; Borgå, Katrine; Christensen, Guttorm; Lierhagen, Syverin; Jenssen, Bjørn Munro

    2015-03-01

    Hepatic concentrations of mercury (Hg), selenium (Se) and cadmium (Cd) were determined in black-legged kittiwakes (Rissa tridactyla) and little auks (Alle alle) from two fjords in Svalbard (Kongsfjorden; 78°57'N, 12°12'E and Liefdefjorden; 79°37'N, 13°20'E). The inflow of Arctic and Atlantic water differs between the two fjords, potentially affecting element accumulation. Trophic positions (TP) were derived from stable nitrogen isotope ratios (δ(15)N), and stable carbon isotope ratios (δ(13)C) were assessed to evaluate the terrestrial influence on element accumulation. Mercury, Cd, TP and δ(13)C varied significantly between locations and years in both species. Trophic position and feeding habits explained Hg and Cd accumulation in kittiwakes, but not in little auks. Biomagnification of Hg and Cd were found in the food webs of both the Atlantic and the Arctic fjord, and no inter-fjord differences were detected. The δ(13)C were higher in the seabirds from Kongsfjorden than in Liefdefjorden, but this did not explain variations in element accumulation. Selenium concentrations were not influenced by Hg accumulation in kittiwakes, indicating baseline levels of Se in this species. In contrast, correlations between Hg and Se and lower Se:Hg ratios in little auks from Kongsfjorden than in Liefdefjorden indicate a more pronounced influence of Se-Hg complex formation in little auks feeding in Atlantic waters.

  4. EPRI wet stacks design guide

    SciTech Connect

    Weilert, C.V.; Pattison, D.C.; Richart, S.D.

    1995-06-01

    Because of the high cost of reheat, wet stacks are being considered for new or retrofit applications of wet FGD systems in the United States. All retrofit systems designed for compliance with Phase I of the Acid Rain Control program under the Clean Air Act have utilized wet stacks. For Phase II, utilities with existing wet FGD systems would benefit from overscrubbing. For those units which currently use bypass reheat, this could be accomplished by closing the bypass to treat the entire boiler flue gas stream. This would require conversion to wet stack operation. Due to the level of interest in these wet stack scenarios for future FGD applications, EPRI, in a tailored collaboration with NYSEG, retained Bums & McDonnell and DynaFlow Systems to prepare a design guide for wet stacks. This paper provides a brief summary of the wet stacks design guide.

  5. Cooler and particulate separator for an off-gas stack

    DOEpatents

    Wright, G.T.

    1991-04-08

    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.

  6. Cooler and particulate separator for an off-gas stack

    DOEpatents

    Wright, George T.

    1992-01-01

    An off-gas stack for a melter 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 pervents 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.

  7. Improved Direct Methanol Fuel Cell Stack

    SciTech Connect

    Wilson, Mahlon S.; Ramsey, John C.

    2005-03-08

    A stack of direct methanol fuel cells exhibiting a circular footprint. A cathode and anode manifold, tie-bolt penetrations and tie-bolts are located within the circular footprint. Each fuel cell uses two graphite-based plates. One plate includes a cathode active area that is defined by serpentine channels connecting the inlet and outlet cathode manifold. The other plate includes an anode active area defined by serpentine channels connecting the inlet and outlet of the anode manifold, where the serpentine channels of the anode are orthogonal to the serpentine channels of the cathode. Located between the two plates is the fuel cell active region.

  8. Thermoacoustic pin stacks. Summary report

    SciTech Connect

    Keolian, R.M.

    1994-07-06

    The construction and testing of a new stack geometry for thermoacoustic engines, called a pin stack, has been started. The stack is at the heart of a class of heat engines that use sound to deliver refrigeration, or use a temperature difference to generate sound. Calculations show that the pin stack should make useful improvements in engine efficiency. About 2000 wires will be hand sewn in a hexagonal lattice between the hot and cold heat exchangers in a sound source using low pressure neon gas between 300 K and 77 K. Thermoacoustics, Refrigeration, Acoustic source, Heat pump.

  9. IAS Stacking Library in IDL

    NASA Astrophysics Data System (ADS)

    Bavouzet, Nicolas; Beelen, Alexandre; Bethermin, Matthieu; Dole, Herve; Ponthieu, Nicolas

    2013-02-01

    This IDL library is designed to be used on astronomical images. Its main aim is to stack data to allow a statistical detection of faint signal, using a prior. For instance, you can stack 160um data using the positions of galaxies detected at 24um or 3.6um, or use WMAP sources to stack Planck data. It can estimate error bars using bootstrap, and it can perform photometry (aperture photometry, or PSF fitting, or other that you can plug). The IAS Stacking Library works with gnomonic projections (RA---TAN), and also with HEALPIX projection.

  10. Stacked insulator induction accelerator gaps

    SciTech Connect

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

    1997-05-01

    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.

  11. Seismic Measurement of the Locations of the Base of Convection Zone and Helium Ionization Zone for Stars in the Kepler Seismic LEGACY Sample

    NASA Astrophysics Data System (ADS)

    Verma, Kuldeep; Raodeo, Keyuri; Antia, H. M.; Mazumdar, Anwesh; Basu, Sarbani; Lund, Mikkel N.; Silva Aguirre, Víctor

    2017-03-01

    Acoustic glitches are regions inside a star where the sound speed or its derivatives change abruptly. These leave a small characteristic oscillatory signature in the stellar oscillation frequencies. With the precision achieved by Kepler seismic data, it is now possible to extract these small amplitude oscillatory signatures, and infer the locations of the glitches. We perform glitch analysis for all the 66 stars in the Kepler seismic LEGACY sample to derive the locations of the base of the envelope convection zone (CZ) and the helium ionization zone. The signature from helium ionization zone is found to be robust for all stars in the sample, whereas the CZ signature is found to be weak and problematic, particularly for relatively massive stars with large errorbars on the oscillation frequencies. We demonstrate that the helium glitch signature can be used to constrain the properties of the helium ionization layers and the helium abundance.

  12. Polyester production by halophilic and halotolerant bacterial strains obtained from mangrove soil samples located in Northern Vietnam.

    PubMed

    Van-Thuoc, Doan; Huu-Phong, Tran; Thi-Binh, Nguyen; Thi-Tho, Nguyen; Minh-Lam, Duong; Quillaguamán, Jorge

    2012-12-01

    This research article reports halophilic and halotolerant bacteria isolated from mangrove forests located in Northern Vietnam. Several of these bacteria were able to synthesize polyhydroxyalkanoates (PHAs). PHAs are polyesters stored by microorganisms under the presence of considerable amounts of a carbon source and deficiency of other essential nutrient such as nitrogen or phosphorous. Mangrove forests in Northern Vietnam are saline coastal habitats that have not been microbiologically studied. Mangrove ecosystems are, in general, rich in organic matter, but deficient in nutrients such as nitrogen and phosphorus. We have found about 100 microorganisms that have adapted to mangrove forests by accumulating PHAs. The production of polyesters might therefore be an integral part of the carbon cycle in mangrove forests. Three of the strains (ND153, ND97, and QN194) isolated from the Vietnamese forests were identified as Bacillus species, while other five strains (QN187, ND199, ND218, ND240, and QN271) were phylogenetically close related to the α-proteobacterium Yangia pacifica. These strains were found to accumulate PHAs in noticeable amounts. Polymer inclusions and chemical structure were studied by transmission electron microscopy and proton nuclear magnetic resonance (NMR) spectroscopy analyses, respectively. Strains ND153, ND97, QN194, QN187, ND240, and QN271 synthesized poly(3-hydroxybutyrate) (PHB) from glucose, whereas strains ND199 and ND218 synthesized poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) from this carbohydrate. With the exception of strain QN194, the strains accumulated PHBV when a combination of glucose and propionate was included in the culture medium. The polymer yields and cell growth reached by one Bacillus isolate, strain ND153, and one Gram-negative bacterium, strain QN271, were high and worth to be researched further. For experiments performed in shake flasks, strain ND153 reached a maximum PHBV yield of 71 wt% and a cell dry weight

  13. Polyester production by halophilic and halotolerant bacterial strains obtained from mangrove soil samples located in Northern Vietnam

    PubMed Central

    Van-Thuoc, Doan; Huu-Phong, Tran; Thi-Binh, Nguyen; Thi-Tho, Nguyen; Minh-Lam, Duong; Quillaguamán, Jorge

    2012-01-01

    This research article reports halophilic and halotolerant bacteria isolated from mangrove forests located in Northern Vietnam. Several of these bacteria were able to synthesize polyhydroxyalkanoates (PHAs). PHAs are polyesters stored by microorganisms under the presence of considerable amounts of a carbon source and deficiency of other essential nutrient such as nitrogen or phosphorous. Mangrove forests in Northern Vietnam are saline coastal habitats that have not been microbiologically studied. Mangrove ecosystems are, in general, rich in organic matter, but deficient in nutrients such as nitrogen and phosphorus. We have found about 100 microorganisms that have adapted to mangrove forests by accumulating PHAs. The production of polyesters might therefore be an integral part of the carbon cycle in mangrove forests. Three of the strains (ND153, ND97, and QN194) isolated from the Vietnamese forests were identified as Bacillus species, while other five strains (QN187, ND199, ND218, ND240, and QN271) were phylogenetically close related to the α-proteobacterium Yangia pacifica. These strains were found to accumulate PHAs in noticeable amounts. Polymer inclusions and chemical structure were studied by transmission electron microscopy and proton nuclear magnetic resonance (NMR) spectroscopy analyses, respectively. Strains ND153, ND97, QN194, QN187, ND240, and QN271 synthesized poly(3-hydroxybutyrate) (PHB) from glucose, whereas strains ND199 and ND218 synthesized poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) from this carbohydrate. With the exception of strain QN194, the strains accumulated PHBV when a combination of glucose and propionate was included in the culture medium. The polymer yields and cell growth reached by one Bacillus isolate, strain ND153, and one Gram-negative bacterium, strain QN271, were high and worth to be researched further. For experiments performed in shake flasks, strain ND153 reached a maximum PHBV yield of 71 wt% and a cell dry weight

  14. Stack Trace Analysis Tool

    SciTech Connect

    2013-02-19

    STAT is a light weight debugging tool that gathers and merges stack traces from all of the processes in a parallell application. STAT uses the MRNet tree based overlay network to broadcast commands from the tool front-end to the STAT daemons and for the front-end to gather the traces from the STAT daemons. As the traces propagate through the MRNet network tree, they are merged across all tasks to from a single call prefix tree. The call prefix tree can be examined to identify tasks with similar function call patterns and to delineate a small set of equivalence slasses. A representative task from each of these classes can then be fed into a full feature debugger like TotalView for root cause analysis.

  15. Effects of land use and sample location on nitrate-stream flow hysteresis descriptors during storm events

    USGS Publications Warehouse

    Feinson, Lawrence S.; Gibs, Jacob; Imbrigiotta, Thomas E.; Garrett, Jessica D.

    2016-01-01

    The U.S. Geological Survey's New Jersey and Iowa Water Science Centers deployed ultraviolet-visible spectrophotometric sensors at water-quality monitoring sites on the Passaic and Pompton Rivers at Two Bridges, New Jersey, on Toms River at Toms River, New Jersey, and on the North Raccoon River near Jefferson, Iowa to continuously measure in-stream nitrate plus nitrite as nitrogen (NO3 + NO2) concentrations in conjunction with continuous stream flow measurements. Statistical analysis of NO3 + NO2 vs. stream discharge during storm events found statistically significant links between land use types and sampling site with the normalized area and rotational direction of NO3 + NO2-stream discharge (N-Q) hysteresis patterns. Statistically significant relations were also found between the normalized area of a hysteresis pattern and several flow parameters as well as the normalized area adjusted for rotational direction and minimum NO3 + NO2 concentrations. The mean normalized hysteresis area for forested land use was smaller than that of urban and agricultural land uses. The hysteresis rotational direction of the agricultural land use was opposite of that of the urban and undeveloped land uses. An r2 of 0.81 for the relation between the minimum normalized NO3 + NO2 concentration during a storm vs. the normalized NO3 + NO2 concentration at peak flow suggested that dilution was the dominant process controlling NO3 + NO2 concentrations over the course of most storm events.

  16. Zigzag stacks and m-regular linear stacks.

    PubMed

    Chen, William Y C; Guo, Qiang-Hui; Sun, Lisa H; Wang, Jian

    2014-12-01

    The contact map of a protein fold is a graph that represents the patterns of contacts in the fold. It is known that the contact map can be decomposed into stacks and queues. RNA secondary structures are special stacks in which the degree of each vertex is at most one and each arc has length of at least two. Waterman and Smith derived a formula for the number of RNA secondary structures of length n with exactly k arcs. Höner zu Siederdissen et al. developed a folding algorithm for extended RNA secondary structures in which each vertex has maximum degree two. An equation for the generating function of extended RNA secondary structures was obtained by Müller and Nebel by using a context-free grammar approach, which leads to an asymptotic formula. In this article, we consider m-regular linear stacks, where each arc has length at least m and the degree of each vertex is bounded by two. Extended RNA secondary structures are exactly 2-regular linear stacks. For any m ≥ 2, we obtain an equation for the generating function of the m-regular linear stacks. For given m, we deduce a recurrence relation and an asymptotic formula for the number of m-regular linear stacks on n vertices. To establish the equation, we use the reduction operation of Chen, Deng, and Du to transform an m-regular linear stack to an m-reduced zigzag (or alternating) stack. Then we find an equation for m-reduced zigzag stacks leading to an equation for m-regular linear stacks.

  17. Stack Characterization in CryoSat Level1b SAR/SARin Baseline C

    NASA Astrophysics Data System (ADS)

    Scagliola, Michele; Fornari, Marco; Di Giacinto, Andrea; Bouffard, Jerome; Féménias, Pierre; Parrinello, Tommaso

    2015-04-01

    CryoSat was launched on the 8th April 2010 and is the first European ice mission dedicated to the monitoring of precise changes in the thickness of polar ice sheets and floating sea ice. CryoSat is the first altimetry mission operating in SAR mode and it carries an innovative radar altimeter called the Synthetic Aperture Interferometric Altimeter (SIRAL), that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for azimuth processing. The current CryoSat IPF (Instrument Processing Facility), Baseline B, was released in operation in February 2012. After more than 2 years of development, the release in operations of the Baseline C is expected in the first half of 2015. It is worth recalling here that the CryoSat SAR/SARin IPF1 generates 20Hz waveforms in correspondence of an approximately equally spaced set of ground locations on the Earth surface, i.e. surface samples, and that a surface sample gathers a collection of single-look echoes coming from the processed bursts during the time of visibility. Thus, for a given surface sample, the stack can be defined as the collection of all the single-look echoes pointing to the current surface sample, after applying all the necessary range corrections. The L1B product contains the power average of all the single-look echoes in the stack: the multi-looked L1B waveform. This reduces the data volume, while removing some information contained in the single looks, useful for characterizing the surface and modelling the L1B waveform. To recover such information, a set of parameters has been added to the L1B product: the stack characterization or beam behaviour parameters. The stack characterization, already included in previous Baselines, has been reviewed and expanded in Baseline C. This poster describes all the stack characterization parameters, detailing what they represent and how they have been computed. In details, such parameters can be summarized in: - Stack

  18. Stacking disorder in ice I.

    PubMed

    Malkin, Tamsin L; Murray, Benjamin J; Salzmann, Christoph G; Molinero, Valeria; Pickering, Steven J; Whale, Thomas F

    2015-01-07

    Traditionally, ice I was considered to exist in two well-defined crystalline forms at ambient pressure: stable hexagonal ice (ice Ih) and metastable cubic ice (ice Ic). However, it is becoming increasingly evident that what has been called cubic ice in the past does not have a structure consistent with the cubic crystal system. Instead, it is a stacking-disordered material containing cubic sequences interlaced with hexagonal sequences, which is termed stacking-disordered ice (ice Isd). In this article, we summarise previous work on ice with stacking disorder including ice that was called cubic ice in the past. We also present new experimental data which shows that ice which crystallises after heterogeneous nucleation in water droplets containing solid inclusions also contains stacking disorder even at freezing temperatures of around -15 °C. This supports the results from molecular simulations, that the structure of ice that crystallises initially from supercooled water is always stacking-disordered and that this metastable ice can transform to the stable hexagonal phase subject to the kinetics of recrystallization. We also show that stacking disorder in ice which forms from water droplets is quantitatively distinct from ice made via other routes. The emerging picture of ice I is that of a very complex material which frequently contains stacking disorder and this stacking disorder can vary in complexity depending on the route of formation and thermal history.

  19. Nondestructive cell evaluation techniques in SOFC stack manufacturing

    NASA Astrophysics Data System (ADS)

    Wunderlich, C.

    2016-04-01

    Independent from the specifics of the application, a cost efficient manufacturing of solid oxide fuel cells (SOFC), its electrolyte membranes and other stack components, leading to reliable long-life stacks is the key for the commercial viability of this fuel cell technology. Tensile and shear stresses are most critical for ceramic components and especially for thin electrolyte membranes as used in SOFC cells. Although stack developers try to reduce tensile stresses acting on the electrolyte by either matching CTE of interconnects and electrolytes or by putting SOFC cells under some pressure - at least during transient operation of SOFC stacks ceramic cells will experience some tensile stresses. Electrolytes are required to have a high Weibull characteristic fracture strength. Practical experiences in stack manufacturing have shown that statistical fracture strength data generated by tests of electrolyte samples give limited information on electrolyte or cell quality. In addition, the cutting process of SOFC electrolytes has a major influence on crack initiation. Typically, any single crack in one the 30 to 80 cells in series connection will lead to a premature stack failure drastically reducing stack service life. Thus, for statistical reasons only 100% defect free SOFC cells must be assembled in stacks. This underlines the need for an automated inspection. So far, only manual processes of visual or mechanical electrolyte inspection are established. Fraunhofer IKTS has qualified the method of optical coherence tomography for an automated high throughput inspection. Alternatives like laser speckle photometry and acoustical methods are still under investigation.

  20. Method for monitoring stack gases for uranium activity

    DOEpatents

    Beverly, C.R.; Ernstberger, E.G.

    1985-07-03

    A method for monitoring the stack gases of a purge cascade of gaseous diffusion plant for uranium activity. A sample stream is taken from the stack gases and contacted with a volume of moisture-laden air for converting trace levels of uranium hexafluoride, if any, in the stack gases into particulate uranyl fluoride. A continuous strip of filter paper from a supply roll is passed through this sampling stream to intercept and gather any uranyl fluoride in the sampling stream. This filter paper is then passed by an alpha scintillation counting device where any radioactivity on the filter paper is sensed so as to provide a continuous monitoring of the gas stream for activity indicative of the uranium content in the stack gases. 1 fig.

  1. Method for monitoring stack gases for uranium activity

    DOEpatents

    Beverly, Claude R.; Ernstberger, Harold G.

    1988-01-01

    A method for monitoring the stack gases of a purge cascade of a gaseous diffusion plant for uranium activity. A sample stream is taken from the stack gases and contacted with a volume of moisture-laden air for converting trace levels of uranium hexafluoride, if any, in the stack gases into particulate uranyl fluoride. A continuous strip of filter paper from a supply roll is passed through this sampling stream to intercept and gather any uranyl fluoride in the sampling stream. This filter paper is then passed by an alpha scintillation counting device where any radioactivity on the filter paper is sensed so as to provide a continuous monitoring of the gas stream for activity indicative of the uranium content in the stack gases.

  2. 49 CFR 178.815 - Stacking test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Stacking test. 178.815 Section 178.815... Stacking test. (a) General. The stacking test must be conducted for the qualification of all IBC design types intended to be stacked. (b) Special preparation for the stacking test. (1) All IBCs...

  3. CAM and stack air sampler design guide

    SciTech Connect

    Phillips, T.D.

    1994-05-13

    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.

  4. Measurement of heat conduction through stacked screens.

    PubMed

    Lewis, M A; Kuriyama, T; Kuriyama, F; Radebaugh, R

    1998-01-01

    This paper describes the experimental apparatus for the measurement of heat conduction through stacked screens as well as some experimental results taken with the apparatus. Screens are stacked in a fiberglass-epoxy cylinder, which is 24.4 mm in diameter and 55 mm in length. The cold end of the stacked screens is cooled by a Gifford-McMahon (GM) cryocooler at cryogenic temperature, and the hot end is maintained at room temperature. Heat conduction through the screens is determined from the temperature gradient in a calibrated heat flow sensor mounted between the cold end of the stacked screens and the GM cryocooler. The samples used for these experiments consisted of 400-mesh stainless steel screens, 400-mesh phosphor bronze screens, and two different porosities of 325-mesh stainless steel screens. The wire diameter of the 400-mesh stainless steel and phosphor bronze screens was 25.4 micrometers and the 325-mesh stainless steel screen wire diameters were 22.9 micrometers and 27.9 micrometers. Standard porosity values were used for the experimental data with additional porosity values used on selected experiments. The experimental results showed that the helium gas between each screen enhanced the heat conduction through the stacked screens by several orders of magnitude compared to that in vacuum. The conduction degradation factor is the ratio of actual heat conduction to the heat conduction where the regenerator material is assumed to be a solid rod of the same cross sectional area as the metal fraction of the screen. This factor was about 0.1 for the stainless steel and 0.022 for the phosphor bronze, and almost constant for the temperature range of 40 to 80 K at the cold end.

  5. Measurement of heat conduction through stacked screens

    NASA Technical Reports Server (NTRS)

    Lewis, M. A.; Kuriyama, T.; Kuriyama, F.; Radebaugh, R.

    1998-01-01

    This paper describes the experimental apparatus for the measurement of heat conduction through stacked screens as well as some experimental results taken with the apparatus. Screens are stacked in a fiberglass-epoxy cylinder, which is 24.4 mm in diameter and 55 mm in length. The cold end of the stacked screens is cooled by a Gifford-McMahon (GM) cryocooler at cryogenic temperature, and the hot end is maintained at room temperature. Heat conduction through the screens is determined from the temperature gradient in a calibrated heat flow sensor mounted between the cold end of the stacked screens and the GM cryocooler. The samples used for these experiments consisted of 400-mesh stainless steel screens, 400-mesh phosphor bronze screens, and two different porosities of 325-mesh stainless steel screens. The wire diameter of the 400-mesh stainless steel and phosphor bronze screens was 25.4 micrometers and the 325-mesh stainless steel screen wire diameters were 22.9 micrometers and 27.9 micrometers. Standard porosity values were used for the experimental data with additional porosity values used on selected experiments. The experimental results showed that the helium gas between each screen enhanced the heat conduction through the stacked screens by several orders of magnitude compared to that in vacuum. The conduction degradation factor is the ratio of actual heat conduction to the heat conduction where the regenerator material is assumed to be a solid rod of the same cross sectional area as the metal fraction of the screen. This factor was about 0.1 for the stainless steel and 0.022 for the phosphor bronze, and almost constant for the temperature range of 40 to 80 K at the cold end.

  6. Measurement of heat conduction through stacked screens

    NASA Technical Reports Server (NTRS)

    Lewis, M. A.; Kuriyama, T.; Kuriyama, F.; Radebaugh, R.

    1998-01-01

    This paper describes the experimental apparatus for the measurement of heat conduction through stacked screens as well as some experimental results taken with the apparatus. Screens are stacked in a fiberglass-epoxy cylinder, which is 24.4 mm in diameter and 55 mm in length. The cold end of the stacked screens is cooled by a Gifford-McMahon (GM) cryocooler at cryogenic temperature, and the hot end is maintained at room temperature. Heat conduction through the screens is determined from the temperature gradient in a calibrated heat flow sensor mounted between the cold end of the stacked screens and the GM cryocooler. The samples used for these experiments consisted of 400-mesh stainless steel screens, 400-mesh phosphor bronze screens, and two different porosities of 325-mesh stainless steel screens. The wire diameter of the 400-mesh stainless steel and phosphor bronze screens was 25.4 micrometers and the 325-mesh stainless steel screen wire diameters were 22.9 micrometers and 27.9 micrometers. Standard porosity values were used for the experimental data with additional porosity values used on selected experiments. The experimental results showed that the helium gas between each screen enhanced the heat conduction through the stacked screens by several orders of magnitude compared to that in vacuum. The conduction degradation factor is the ratio of actual heat conduction to the heat conduction where the regenerator material is assumed to be a solid rod of the same cross sectional area as the metal fraction of the screen. This factor was about 0.1 for the stainless steel and 0.022 for the phosphor bronze, and almost constant for the temperature range of 40 to 80 K at the cold end.

  7. Evaluation of airborne particulate matter and metals data in personal, indoor and outdoor environments using ED-XRF and ICP-MS and co-located duplicate samples

    NASA Astrophysics Data System (ADS)

    Niu, Jianjun; Rasmussen, Pat E.; Wheeler, Amanda; Williams, Ron; Chénier, Marc

    2010-01-01

    Factors and sources affecting measurement uncertainty associated with monitoring metals in airborne particulate matter (PM) were investigated as part of the Windsor, Ontario Exposure Assessment Study (WOEAS). The assessment was made using co-located duplicate samples and a comparison of two analytical approaches: ED-XRF and ICP-MS. Sampling variability was estimated using relative percent difference (RPD) of co-located duplicate samples. The comparison of ICP-MS and ED-XRF results yields very good correlations ( R2 ≥ 0.7) for elements present at concentrations that pass both ICP-MS and ED-XRF detection limits (e.g. Fe, Mn, Zn, Pb and Cu). PM concentration ranges (median, sample number) of 24-h indoor PM 10 and personal PM 10 filters, and outdoor PM 2.5 filters were determined to be 2.2-40.7 (11.0, n = 48) μg m -3, 8.0-48.3 (11.9, n = 48) μg m -3, and 17.1-42.3 (21.6, n = 18) μg m -3, respectively. The gravimetric analytical results reveal that the variations in PM mass measurements for same-day sampling are insignificant compared to temporal or spatial variations: 92%, 100% and 96% of indoor, outdoor and personal duplicate samples, respectively, pass the quality criteria (RPD ≤ 20%). Uncertainties associated with ED-XRF elemental measurements of S, Ca, Mn, Fe and Zn for 24-h filter samples are low: 78%-100% of the duplicate samples passed the quality criteria. In the case of 24-h filter samples using ICP-MS, more elements passed the quality criteria due to the lower detection limits. These were: Li, Na, K, Ca, Si, Al, V, Fe, Mn, Co, Cu, Mo, Ag, Zn, Pb, As, Mg, Sb, Sn, Sr, Th, Ti, Tl, and U. Low air concentrations of metals (near or below instrumental detection limits) and/or inadvertent introduction of metal contamination are the main causes for excluding elements based on the pass/fail criteria. Uncertainty associated with elemental measurements must be assessed on an element-by-element basis.

  8. Ribosomes in a Stacked Array

    PubMed Central

    Yamashita, Yui; Kadokura, Yoshitomo; Sotta, Naoyuki; Fujiwara, Toru; Takigawa, Ichigaku; Satake, Akiko; Onouchi, Hitoshi; Naito, Satoshi

    2014-01-01

    Expression of CGS1, which codes for an enzyme of methionine biosynthesis, is feedback-regulated by mRNA degradation in response to S-adenosyl-l-methionine (AdoMet). In vitro studies revealed that AdoMet induces translation arrest at Ser-94, upon which several ribosomes stack behind the arrested one, and mRNA degradation occurs at multiple sites that presumably correspond to individual ribosomes in a stacked array. Despite the significant contribution of stacked ribosomes to inducing mRNA degradation, little is known about the ribosomes in the stacked array. Here, we assigned the peptidyl-tRNA species of the stacked second and third ribosomes to their respective codons and showed that they are arranged at nine-codon intervals behind the Ser-94 codon, indicating tight stacking. Puromycin reacts with peptidyl-tRNA in the P-site, releasing the nascent peptide as peptidyl-puromycin. This reaction is used to monitor the activity of the peptidyltransferase center (PTC) in arrested ribosomes. Puromycin reaction of peptidyl-tRNA on the AdoMet-arrested ribosome, which is stalled at the pre-translocation step, was slow. This limited reactivity can be attributed to the peptidyl-tRNA occupying the A-site at this step rather than to suppression of PTC activity. In contrast, puromycin reactions of peptidyl-tRNA with the stacked second and third ribosomes were slow but were not as slow as pre-translocation step ribosomes. We propose that the anticodon end of peptidyl-tRNA resides in the A-site of the stacked ribosomes and that the stacked ribosomes are stalled at an early step of translocation, possibly at the P/E hybrid state. PMID:24652291

  9. Corsi's block-tapping task: standardization and location in factor space with the WAIS-R for two normal samples of older adults.

    PubMed

    Saggino, Aristide; Balsamo, Michela; Grieco, Anna; Cerbone, Maria Rosaria; Raviele, Nicla Nicolina

    2004-06-01

    Corsi's block-tapping task and WAIS-R were administered to two Italian samples of 200 normal older adults (aged 65-74 years and 75-100 years). Corsi's reliabilities and standardization data are shown. Additionally, Corsi's location in the factor space of cognitive abilities represented by the 11 WAIS-R subtests is presented. Corsi's test seems to be a reliable one for older Italians. It seems also to be a measure of general intelligence in those 65-74 years of age and a measure of the Freedom from Distractibility factor in subjects 75 years and older.

  10. Stacking Faults in Cotton Fibers

    NASA Astrophysics Data System (ADS)

    Divakara, S.; Niranjana, A. R.; Siddaraju, G. N.; Somashekar, R.

    2011-07-01

    The stacking faults in different variety of cotton fibers have been quantified using wide-angle X-ray scattering (WAXS) data. Exponential functions for the column length distribution have been used for the determination of microstructural parameters. The crystal imperfection parameters like crystal size , lattice strain (g in %), stacking faults (αd) and twin faults (β) have been determined by profile analysis using Fourier method of Warren. We examined different variety of raw cotton fibers using WAXS techniques. In all these cases we note that, the stacking faults are quite significant in determining the property of cotton fibers.

  11. PieceStack: Toward Better Understanding of Stacked Graphs.

    PubMed

    Wu, Tongshuang; Wu, Yingcai; Shi, Conglei; Qu, Huamin; Cui, Weiwei

    2016-02-24

    Stacked graphs have been widely adopted in various fields, because they are capable of hierarchically visualizing a set of temporal sequences as well as their aggregation. However, because of visual illusion issues, connections between overly-detailed individual layers and overly-generalized aggregation are intercepted. Consequently, information in this area has yet to be fully excavated. Thus, we present PieceStack in this paper, to reveal the relevance of stacked graphs in understanding intrinsic details of their displayed shapes. This new visual analytic design interprets the ways through which aggregations are generated with individual layers by interactively splitting and re-constructing the stacked graphs. A clustering algorithm is designed to partition stacked graphs into sub-aggregated pieces based on trend similarities of layers. We then visualize the pieces with augmented encoding to help analysts decompose and explore the graphs with respect to their interests. Case studies and a user study are conducted to demonstrate the usefulness of our technique in understanding the formation of stacked graphs.

  12. Project W420 Air Sampler Probe Placement Qualification Tests for Four 6-Inch Diameter Stacks: 296-A-25, 296-B-28, 296-S-22, and 296-T-18

    SciTech Connect

    Maughan, A.D.; Glissmeyer, J.A.

    1998-09-30

    The W420 project covers the upgrading of effluent monitoring systems at six ventilation exhaust stacks in tank-farm facilities at the U.S. Department of Energy's Hanford Site. The discharge stacks of five of the six systems will be completely replaced. Four of these (296-A-25, 296-B-28, 296-S-22, and 296-T-18) will be of the same size, 6-inches in diameter and about 12-ft high. This report documents tests that were conducted to verify that these four stacks meet the applicable regulatory criteria regarding the placement of the air sampling probe. These criteria ensure that the contaminants in the stack are well mixed with the airflow at the location of the probe such that the extracted sample represents the whole. There are also criteria addressing the transport of the sample to the collection device. These are not covered in this report, but will need to be addressed later. These tests were conducted by Pacific Northwest National Laboratory on a full-scale model of the 6-inch stick. The sequence of tests addresses the acceptability of the flow angle relative to the probe and the uniformity of air velocity and gaseous and particle tracers in the cross section of the stack. All tests were successful, and all acceptance criteria were met.

  13. Detection of environmental DNA of Bigheaded Carps in samples collected from selected locations in the St. Croix River and in the Mississippi River

    USGS Publications Warehouse

    Amberg, Jon J.; McCalla, S. Grace; Miller, Loren; Sorensen, Peter; Gaikowski, Mark P.

    2013-01-01

    The use of molecular methods, such as the detection of environmental deoxyribonucleic acid (eDNA), have become an increasingly popular tool in surveillance programs that monitor for the presence of invasive species in aquatic systems. One early application of these methods in aquatic systems was surveillance for DNA of Asian carps (specifically bighead carp Hypophthalmichthys nobilis and silver carp H. molitrix) in water samples taken from the Chicago Area Waterway System. The ability to identify DNA of a species in an environmental sample presents a potentially powerful tool because these sensitive analyses can presumably detect the presence of DNA in water even when the species is not abundant or are difficult to catch or monitor with traditional gear. Prior to research presented in this report, an initial eDNA surveillance effort was completed in selected locations in the Upper Mississippi and St. Croix Rivers in 2011 after the capture of a bighead carp in the St. Croix River near Prescott, WI. Data presented in this report were developed to duplicate the 2011 monitoring results from the Upper Mississippi and St. Croix Rivers and to provide critical insight into the technique to inform future work in these locations. We specifically sought to understand the potential confounding effects of other pathways of eDNA movement (e.g., fish-eating birds, watercraft) on the variation in background DNA by collecting water samples from (1) sites within the St. Croix River and the upper Mississippi River where the DNA of silver carp was previously detected, (2) sites considered to be free of Asian carp, and (3) a site known to have a large population of Asian carp. We also sought to establish a baseline Asian carp eDNA signature to which future eDNA sampling efforts could be compared. All samples taken as part of this effort were processed using conventional polymerase chain reaction (PCR) according to procedures outlined in the U.S. Army Corps of Engineers Quality

  14. Learning algorithms for stack filter classifiers

    SciTech Connect

    Porter, Reid B; Hush, Don; Zimmer, Beate G

    2009-01-01

    Stack Filters define a large class of increasing filter that is used widely in image and signal processing. The motivations for using an increasing filter instead of an unconstrained filter have been described as: (1) fast and efficient implementation, (2) the relationship to mathematical morphology and (3) more precise estimation with finite sample data. This last motivation is related to methods developed in machine learning and the relationship was explored in an earlier paper. In this paper we investigate this relationship by applying Stack Filters directly to classification problems. This provides a new perspective on how monotonicity constraints can help control estimation and approximation errors, and also suggests several new learning algorithms for Boolean function classifiers when they are applied to real-valued inputs.

  15. Converting factors for stacked wood

    Treesearch

    C. A. Bickford

    1957-01-01

    Though the "cord" is used as a standard unit of measure for stacked wood, there is much confusion as to what a cord is and how it can be properly converted to other units of measure. The amount of solid wood in a pile varies greatly depending on the size, straightness, and evenness of the material in the pile, and also on the closeness of stacking.

  16. GINSU: Guaranteed Internet Stack Utilization

    DTIC Science & Technology

    2005-11-01

    Exokernel (logical stack encapsulation and dynamic packet classification), and NAI Labs’ AMP Channel Stack (traffic isolation) and combines and extends...using an efficient tri-based approach pioneered in the Exokernel and ported to the Linux platform as part of this research. Tries are populated on...filtering subsystem of the MIT Exokernel . Accordingly it has its strengths – simplicity and efficiency – and its weaknesses – lack of support for

  17. Hair sampling location in harbor seals (Phoca vitulina) affects selenium and mercury concentrations: implications for study design of trace element determination in pinnipeds.

    PubMed

    McHuron, Elizabeth A; Harvey, James T; Castellini, J Margaret; O'Hara, Todd M

    2012-11-01

    Hair is used to determine trace elements exposure and status of pinnipeds because it is an excretory route for many elements and can be collected non-lethally. Despite increased use, there have been few studies on how sampling designs and procedures (e.g., hair type, collection site) affect results. The objective of this study was to determine whether concentrations of an essential (selenium; Se) and non-essential element (mercury; Hg) differed between hair samples collected from two body locations on harbor seals (Phoca vitulina). Concentrations of Se and total Hg (THg) differed between mid-dorsal midline and neck samples, and although the absolute differences were relatively small (Δ(absolute) Se = 0.69 μg g(-1), Δ(absolute) THg = 2.86 μg g(-1)), the relative differences were large (Δ(relative) Se = 49%, Δ(relative) THg = 17%). These differences highlight the need to standardize the collection site for trace element determination in pinnipeds.

  18. Investigating the use of 232Th/230Th as a dust proxy using co-located seawater and sediment samples from the low-latitude North Atlantic

    NASA Astrophysics Data System (ADS)

    Rowland, George H.; Ng, Hong Chin; Robinson, Laura F.; McManus, Jerry F.; Mohamed, Kais J.; McGee, David

    2017-10-01

    The thorium isotope ratio 232Th/230Th can be measured in seawater and sediment samples, and has been used as a proxy to reconstruct lithogenic fluxes to the oceans for the modern day and the Pleistocene. There has not yet been a systematic study testing the proxy using the 232Th/230Th ratio in seawater and the ratio recorded in the underlying sediment. In this study we use co-located core-top sediments and seawater samples from five seamount sites spanning the tropical North Atlantic to investigate the link between seawater and sediment 232Th/230Th ratios across a range of water depths. Our results indicate that a broad correlation exists between seawater and sedimentary 232Th/230Th ratios. Both seawater and sedimentary 232Th/230Th ratios record a signal consistent with decreasing lithogenic input east to west, from Africa to South America. However, calculated 232Th fluxes for the core-top sediment samples indicate a strong dependence on depth, with up to a factor of ∼4 difference from shallow (<600 m) to deep sites (>2900 m). This depth dependence is likely caused by either a deficit of 230Th burial at depth compared to the production in the overlying water column, through addition of 232Th, or by a combination of the two. By comparing seawater and sedimentary 232Th/230Th ratios we derive an apparent fractional solubility of 232Th of 29 ± 3%, in reasonable agreement with the upper end of existing estimates.

  19. Attachment method for stacked integrated circuit (IC) chips

    DOEpatents

    Bernhardt, A.F.; Malba, V.

    1999-08-03

    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 to other chips or a circuit board can be accomplished via the side-located pads. The pads on the side of a chip are connected to metal lines on a flexible plastic tape (flex) by anisotropically conductive adhesive (ACA). Metal lines on the flex are likewise connected to other pads on chips and/or to pads on a circuit board. In the case of a stack of DRAM chips, pads to corresponding address lines on the various chips may be connected to the same metal line on the flex to form an address bus. This method has the advantage of reducing the number of connections required to be made to the circuit board due to bussing; the flex can accommodate dimensional variation in the alignment of chips in the stack; bonding of the ACA is accomplished at low temperature and is otherwise simpler and less expensive than solder bonding; chips can be bonded to the ACA all at once if the sides of the chips are substantially coplanar, as in the case for stacks of identical chips, such as DRAM. 12 figs.

  20. Attachment method for stacked integrated circuit (IC) chips

    DOEpatents

    Bernhardt, Anthony F.; Malba, Vincent

    1999-01-01

    An attachment method for stacked integrated circuit (IC) chips. 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 to other chips or a circuit board can be accomplished via the side-located pads. The pads on the side of a chip are connected to metal lines on a flexible plastic tape (flex) by anisotropically conductive adhesive (ACA). Metal lines on the flex are likewise connected to other pads on chips and/or to pads on a circuit board. In the case of a stack of DRAM chips, pads to corresponding address lines on the various chips may be connected to the same metal line on the flex to form an address bus. This method has the advantage of reducing the number of connections required to be made to the circuit board due to bussing; the flex can accommodate dimensional variation in the alignment of chips in the stack; bonding of the ACA is accomplished at low temperature and is otherwise simpler and less expensive than solder bonding; chips can be bonded to the ACA all at once if the sides of the chips are substantially coplanar, as in the case for stacks of identical chips, such as DRAM.

  1. 30 CFR 77.302 - Bypass stacks.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ....302 Bypass stacks. Thermal dryer systems shall include a bypass stack, relief stack or individual discharge stack provided with automatic venting which will permit gases from the dryer heating unit to bypass the heating chamber and vent to the outside atmosphere during any shutdown operation. ...

  2. 30 CFR 77.302 - Bypass stacks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....302 Bypass stacks. Thermal dryer systems shall include a bypass stack, relief stack or individual discharge stack provided with automatic venting which will permit gases from the dryer heating unit to bypass the heating chamber and vent to the outside atmosphere during any shutdown operation. ...

  3. 49 CFR 178.1055 - Stacking test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Stacking test. 178.1055 Section 178.1055... Containers § 178.1055 Stacking test. (a) General. The stacking test must be conducted for the qualification of all Flexible Bulk Containers design types. (b) Special preparation for the stacking test....

  4. 40 CFR 761.347 - First level sampling-waste from existing piles.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... destined for off-site disposal stacked up uniformly to a peak that is a point centered above the center of...) Setting up the sample site selection system from a pile. Locate a sample in a pile by the use of three... distance around the bottom of the pile. Determine r from b in one of two ways: (1) Multiply c by a...

  5. Real-time focal stack compositing for handheld mobile cameras

    NASA Astrophysics Data System (ADS)

    Solh, Mashhour

    2013-03-01

    Extending the depth of field using a single lens camera on a mobile device can be achieved by capturing a set of images each focused at a different depth or focal stack then combine these samples of the focal stack to form a single all-in-focus image or an image refocused at a desired depth of field. Focal stack compositing in real time for a handheld mobile camera has many challenges including capturing, processing power, handshaking, rolling shutter artifacts, occlusion, and lens zoom effect. In this paper, we describe a system for a real time focal stack compositing system for handheld mobile device with an alignment and compositing algorithms. We will also show all-in-focus images captured and processed by a cell phone camera running on Android OS.

  6. Association of Urinary Activity of MMP-2 with Microalbuminuria in an Isolated Sample of Subjects Living in High Altitude Rural Locations in México.

    PubMed

    Hernández-Hernández, Magda Elena; Morales-Romero, Jaime; Sampieri, Clara Luz; Luna Lozano, Diego Jesús; Valencia Lezama, Isidra Del Carmen; Muñoz Contreras, Mónica Janett; Rodríguez Hernández, Arturo

    2017-09-01

    Hernández-Hernández, Magda Elena, Jaime Morales-Romero, Clara Luz Sampieri, Diego Jesús Luna Lozano, Isidra del Carmen Valencia Lezama, Mónica Janett Muñoz Contreras, and Arturo Rodríguez Hernández. Association of urinary activity of MMP-2 with microalbuminuria in an isolated sample of subjects living in high altitude rural locations in México. High Alt Med Biol. 18:209-218, 2017.-Matrix metalloproteinases (MMP) are implicated in remodeling of the renal extracellular matrix. In a cross-sectional study we evaluated renal impairment in general population of high-altitude rural locations in México. Multivariable analysis was performed to identify the association between MMP-2 and MMP-9 and microalbuminuria. Twenty-eight (20.9%) subjects with renal impairment (WRI) and 106 (79.1%) without renal impairment were included. No differences were found relating to sex, location, marital status, current habits, weight, height, body mass index, waist size in males, creatinine in males, and uric acid. In contrast, differences were found among age, level of education, waist size in general and in females, creatinine in general and in females, urinary albumin, urea, glucose, total cholesterol, and triglycerides. Proportions of hypertension, type 2 diabetes mellitus, central abdominal obesity, hypertriglyceridemia, and hypercholesterolemia were greater in the group WRI. Presence of urinary MMP-2 or of both urinary gelatinases and arbitrary unit (AU) values ≥P90 were associated with microalbuminuria. We conclude that AU values ≥P90 of urinary MMP-2 (OR = 20.1, p = 0.002) is associated with microalbuminuria.

  7. Fuel cell stack compressive loading system

    DOEpatents

    Fahle, Ronald W.; Reiser, Carl A.

    1982-01-01

    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.

  8. Analysis of the effects of ionospheric sampling of reflection points near-path, for high-frequency single-site-location direction finding systems. Master's thesis

    SciTech Connect

    Filho, C.A.

    1990-12-01

    This thesis suggests a method to estimate the current value of an ionospheric parameter. The proposed method is based on the known variability of the observed current values near path and utilizes data derived from ionospheric sampling measurements. Analysis of errors is provided in Single-Site-Location High-Frequency Direction Finding (SSL-HFDF), arising from ionospheric irregularities such as Es (sporadic E), ionospheric tilts, and traveling ionospheric disturbances (TIDs). The characteristics of Es, tilts and TIDs for mid-latitudes are summarized in tables. The spatial and temporal coherence of ionospheric variabilities and irregularities is analyzed over the electron density. Practical results, measurements, and studies are presented on SSL-HFDF. A survey of characteristics of the ionosphere in the equatorial region is also provided. Finally, some recommendations are given to maximize the applicability of the proposed method.

  9. Chemical Diversity and Antimicrobial Activity of Volatile Compounds from Zanthoxylum zanthoxyloides Lam. according to Compound Classes, Plant Organs and Senegalese Sample Locations.

    PubMed

    Tine, Yoro; Diop, Abdoulaye; Diatta, William; Desjobert, Jean-Marie; Boye, Cheikh Saad Bouh; Costa, Jean; Wélé, Alassane; Paolini, Julien

    2017-01-01

    The chemical diversity of Zanthoxylum zanthoxyloides growing wild in Senegal was studied according to volatile compound classes, plant organs and sample locations. The composition of fruit essential oil was investigated using an original targeted approach based on the combination of gas chromatography (GC) and liquid chromatography (LC) both coupled with mass spectrometry (MS). The volatile composition of Z. zanthoxyloides fruits exhibited relative high amounts of hydrocarbon monoterpenes (24.3 - 55.8%) and non-terpenic oxygenated compounds (34.5 - 63.1%). The main components were (E)-β-ocimene (12.1 - 39%), octyl acetate (11.6 - 21.8%) and decanol (9.7 - 15.4%). The GC and GC/MS profiling of fruit essential oils showed a chemical variability according to geographical locations of plant material. The LC/MS/MS analysis of fruit oils allowed the detection of seven coumarins in trace content. The chemical composition of fruit essential oils was compared with volatile fractions of leaves and barks (root and trunk) from the same plant station. Hexadecanoic acid, germacrene D and decanal were identified as the major constituents of leaves whereas the barks (root and trunk) were dominated by pellitorine (85.8% and 57%, respectively), an atypic linear compound with amide group. The fruit essential oil exhibited interesting antimicrobial activities against Staphylococcus aureus and Candida albicans, particularly the alcohol fraction of the oil.

  10. Stacking-Dependent Electronic Structure of Trilayer Graphene Resolved by Nanospot Angle-Resolved Photoemission Spectroscopy.

    PubMed

    Bao, Changhua; Yao, Wei; Wang, Eryin; Chen, Chaoyu; Avila, José; Asensio, Maria C; Zhou, Shuyun

    2017-03-08

    The crystallographic stacking order in multilayer graphene plays an important role in determining its electronic structure. In trilayer graphene, rhombohedral stacking (ABC) is particularly intriguing, exhibiting a flat band with an electric-field tunable band gap. Such electronic structure is distinct from simple hexagonal stacking (AAA) or typical Bernal stacking (ABA) and is promising for nanoscale electronics and optoelectronics applications. So far clean experimental electronic spectra on the first two stackings are missing because the samples are usually too small in size (μm or nm scale) to be resolved by conventional angle-resolved photoemission spectroscopy (ARPES). Here, by using ARPES with a nanospot beam size (NanoARPES), we provide direct experimental evidence for the coexistence of three different stackings of trilayer graphene and reveal their distinctive electronic structures directly. By fitting the experimental data, we provide important experimental band parameters for describing the electronic structure of trilayer graphene with different stackings.

  11. Stacking interactions and DNA intercalation

    SciTech Connect

    Li, Dr. Shen; Cooper, Valentino R; Thonhauser, Prof. Timo; Lundqvist, Prof. Bengt I.; Langreth, David C.

    2009-01-01

    The relationship between stacking interactions and the intercalation of proflavine and ellipticine within DNA is investigated using a nonempirical van der Waals density functional for the correlation energy. Our results, employing a binary stack model, highlight fundamental, qualitative differences between base-pair base-pair interactions and that of the stacked intercalator base pair system. Most notable result is the paucity of torque which so distinctively defines the Twist of DNA. Surprisingly, this model, when combined with a constraint on the twist of the surrounding base-pair steps to match the observed unwinding of the sugar-phosphate backbone, was sufficient for explaining the experimentally observed proflavine intercalator configuration. Our extensive mapping of the potential energy surface of base-pair intercalator interactions can provide valuable information for future nonempirical studies of DNA intercalation dynamics.

  12. Improved method for quantifying levoglucosan and related monosaccharide anhydrides in atmospheric aerosols and application to samples from urban and tropical locations.

    PubMed

    Zdráhal, Zbynek; Oliveira, José; Vermeylen, Reinhilde; Claeys, Magda; Maenhaut, Willy

    2002-02-15

    An improved analytical method was developed and validated for the determination of the monosaccharide anhydrides levoglucosan, mannosan, and galactosan in atmospheric aerosol samples. The method uses an external recovery standard, extraction in dichloromethane, trimethylsilylation, addition of an internal standard (1-phenyl dodecane), and analysis by gas chromatography with flame ionization detection (GC-FID) and gas chromatography/mass spectrometry (GC/MS). As external recovery standard, we selected 1,2,3-trihydroxyhexane, which has a similar polarity as the monosaccharide anhydrides; furthermore, it was ensured that the trimethylsilylation step leads to complete derivatization into trimethylsilyl ethers. The reproducibility of the combined trimethylsilylation and analysis of levoglucosan was about 2% for standard solutions, whereas the precision of the entire method for the sum of all three monosaccharide anhydrides (MAs) in real aerosol filter samples was about 5%. The method was applied to aerosol samples from urban and tropical locations. The atmospheric concentration of the MAs in fine (<2.5 microm) aerosols at a primary forest site in Rondĵnia, Brazil, was on average 2.15 microg m(-3) during the dry season when intensive biomass burning occurs, which was almost 400 times higher than during the wet (nonburning) season. Urban total aerosols collected in Gent, Belgium, showed an average atmospheric concentration of MAs of 0.56 microg m(-3) for the winter season, which was a factor of 20 higher than for the summer season. The carbon in the MAs accounted on average for about 5.1% and 1.8% of the organic carbon in the Brazilian dry season and Gent winter aerosols, respectively. Levoglucosan was the major MA, with a relative abundance in the range of 76-93%.

  13. Pressurized electrolysis stack with thermal expansion capability

    DOEpatents

    Bourgeois, Richard Scott

    2015-07-14

    The present techniques provide systems and methods for mounting an electrolyzer stack in an outer shell so as to allow for differential thermal expansion of the electrolyzer stack and shell. Generally, an electrolyzer stack may be formed from a material with a high coefficient of thermal expansion, while the shell may be formed from a material having a lower coefficient of thermal expansion. The differences between the coefficients of thermal expansion may lead to damage to the electrolyzer stack as the shell may restrain the thermal expansion of the electrolyzer stack. To allow for the differences in thermal expansion, the electrolyzer stack may be mounted within the shell leaving a space between the electrolyzer stack and shell. The space between the electrolyzer stack and the shell may be filled with a non-conductive fluid to further equalize pressure inside and outside of the electrolyzer stack.

  14. The Direct FuelCell™ stack engineering

    NASA Astrophysics Data System (ADS)

    Doyon, J.; Farooque, M.; Maru, H.

    FuelCell Energy (FCE) has developed power plants in the size range of 300 kW to 3 MW for distributed power generation. Field-testing of the sub-megawatt plants is underway. The FCE power plants are based on its Direct FuelCell™ (DFC) technology. This is so named because of its ability to generate electricity directly from a hydrocarbon fuel, such as natural gas, by reforming it inside the fuel cell stack itself. All FCE products use identical 8000 cm 2 cell design, approximately 350-400 cells per stack, external gas manifolds, and similar stack compression systems. The difference lies in the packaging of the stacks inside the stack module. The sub-megawatt system stack module contains a single horizontal stack whereas the MW-class stack module houses four identical vertical stacks. The commonality of the design, internal reforming features, and atmospheric operation simplify the system design, reduce cost, improve efficiency, increase reliability and maintainability. The product building-block stack design has been advanced through three full-size stack operations at company's headquarters in Danbury, CT. The initial proof-of-concept of the full-size stack design was verified in 1999, followed by a 1.5 year of endurance verification in 2000-2001, and currently a value-engineered stack version is in operation. This paper discusses the design features, important engineering solutions implemented, and test results of FCE's full-size DFC stacks.

  15. Assessment of the Idaho National Laboratory Hot Fuel Examination Facility Stack Monitoring Site for Compliance with ANSI/HPS N13.1 1999

    SciTech Connect

    Glissmeyer, John A.; Flaherty, Julia E.

    2010-08-27

    This document reports on a series of tests to determine whether the location of the air sampling probe in the Hot Fuels Examination Facility (HFEF) heating, ventilation and air conditioning (HVAC) exhaust duct meets the applicable regulatory criteria regarding the placement of an air sampling probe. Federal regulations require that a sampling probe be located in the exhaust stack according to the criteria of the ANSI/HPS N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stacks and Ducts of Nuclear Facilities. These criteria address the capability of the sampling probe to extract a sample that is representative of the effluent stream. The tests conducted by PNNL during July 2010 on the HFEF system are described in this report. The sampling probe location is approximately 20 feet from the base of the stack. The stack base is in the second floor of the HFEF, and has a building ventilation stream (limited potential radioactive effluent) as well as a process stream (potential radioactive effluent, but HEPA-filtered) that feeds into it. The tests conducted on the duct indicate that the process stream is insufficiently mixed with the building ventilation stream. As a result, the air sampling probe location does not meet the criteria of the N13.1-1999 standard. The series of tests consists of various measurements taken over a grid of points in the duct cross section at the proposed sampling-probe location. The results of the test series on the HFEF exhaust duct as it relates to the criteria from ANSI/HPS N13.1-1999 are desribed in this report. Based on these tests, the location of the air sampling probe does not meet the requirements of the ANSI/HPS N13.1-1999 standard, and modifications must be made to either the HVAC system or the air sampling probe for compliance. The recommended approaches are discussed and vary from sampling probe modifications to modifying the junction of the two air exhaust streams.

  16. Summit crater lake observations, and the location, chemistry, and pH of water samples near Mount Chiginagak volcano, Alaska: 2004-2012

    USGS Publications Warehouse

    Schaefer, Janet R.; Scott, William E.; Evans, William C.; Wang, Bronwen; McGimsey, Robert G.

    2013-01-01

    maximum depth of 45 m (resulting pH ~2.9), and preventing the annual salmon run in the King Salmon River. A simultaneous release of gas and acidic aerosols from the crater caused widespread vegetation damage along the flow path. Since 2005, we have been monitoring the crater lake water that continues to flow into Mother Goose Lake by collecting surface water samples for major cation and anion analysis, measuring surface-water pH of affected drainages, and photo-documenting the condition of the summit crater lake. This report describes water sampling locations, provides a table of chemistry and pH measurements, and documents the condition of the summit crater between 2004 and 2011. In September 2013, the report was updated with results of water-chemistry samples collected in 2011 and 2012, which were added as an addendum.

  17. Resolving Lithospheric Interfaces Using SS Waveform Stacks

    NASA Astrophysics Data System (ADS)

    Rychert, C. A.; Shearer, P. M.

    2009-12-01

    We image lithospheric interfaces globally using variations in the character of SS waveform stacks. The variations are caused by reflected phases, i.e., underside reflections (SS precursors) and topside multiples (SS reverberations), created at discontinuities near the midpoint of the SS raypath. Stacks from continental versus oceanic bouncepoint regions produce distinctly different SS waveforms, consistent with the large continent/ocean difference in crustal thickness. This difference can also be seen in data binned in bouncepoint caps with 10° radii. We develop a method to invert for the depth of lithospheric discontinuities using a modeling technique in which a reference waveform is convolved with a crustal operator. We demonstrate the utility of this method by inverting for Moho depth beneath Asia, where continental bouncepoint coverage is highest. The results from our method are correlated (correlation coefficient 0.8) with the CRUST 2.0 values averaged over sample bins of 10° radius. Beneath oceans, crustal depths are too shallow to be resolved by this method. However, SS stacks from regions in the Pacific where bouncepoint coverage is highest suggest the presence of a deeper velocity decrease with depth, which may be related to the lithosphere-asthenosphere boundary. Inversions for the depth of the interface indicate that it is centered at 15 - 170 km depth beneath the best-resolved bins. The character of the discontinuity varies systematically, increasing in depth from the East Pacific Rise towards older oceanic lithosphere. This imaging method has broad lateral resolution in comparison to receiver functions, but has the potential to sample lithospheric interfaces in regions where station coverage may be sparse.

  18. Performance of hot stacked-sinter forged Bi2223 ceramics

    NASA Astrophysics Data System (ADS)

    Noudem, J. G.; Guilmeau, E.; Chateigner, D.; Ouladdiaf, B.; Bourgault, D.

    2004-08-01

    Dense Bi2223 superconductors have been successfully formed by hot stacking-forging process (HSF). Neutron diffraction measurements were used to investigate the bulk textures of HSF-Bi2223 samples. Angular dependence of transport critical current density, Jc values were measured at various temperatures and different applied magnetic fields. Several textured pieces were hot-stacked. This procedure leads to an increase of both the sample thickness and the nominal engineering critical current ( Ic), favourable hints for use of textured-Bi2223 in power generation supplies.

  19. V-stack piezoelectric actuator

    NASA Astrophysics Data System (ADS)

    Ardelean, Emil V.; Clark, Robert L.

    2001-07-01

    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.

  20. Late Pleistocene Sea Level Stack

    NASA Astrophysics Data System (ADS)

    Spratt, R. M.; Lisiecki, L. E.

    2014-12-01

    Sea level reconstructions have been created using wide variety of proxies and models. The accuracy of individual sea level reconstructions is limited by measurement, noise, local variations in salinity and temperature, and the assumptions particular to each reconstruction. To address these limitations, we have created a sea level stack (average) which increases the signal-to-noise ratio of sea level estimates by combining 5-7 sea level reconstructions over the last 800 kyr. Principal Component analysis (PCA) of seven sea level records from 0-430 kyr ago shows that 82% of the variance in these records is explained by their first principal component (i.e., the stack). Additionally, a stack of just the 5 longer records that extends to 800 kyr closely matches the timing and amplitude of our seven-record mean. We find that the mean sea level estimate for Marine Isotope Stage (MIS) 5e is 0-4 m above modern, and that the standard deviation of individual estimates is 11 m. Mean sea level estimates for MIS 11 are 12-16 m above modern with a standard deviation of 30 m. Due to the large variability between individual reconstructions, our sea level stack may provide more robust sea level estimates than any single technique.

  1. Progress Update: Stack Project Complete

    SciTech Connect

    Cody, Tom

    2010-01-01

    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.

  2. Multibeam collimator uses prism stack

    NASA Technical Reports Server (NTRS)

    Minott, P. O.

    1981-01-01

    Optical instrument creates many divergent light beams for surveying and machine element alignment applications. Angles and refractive indices of stack of prisms are selected to divert incoming laser beam by small increments, different for each prism. Angles of emerging beams thus differ by small, precisely-controlled amounts. Instrument is nearly immune to vibration, changes in gravitational force, temperature variations, and mechanical distortion.

  3. Multilayer Piezoelectric Stack Actuator Characterization

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Jones, Christopher M.; Aldrich, Jack B.; Blodget, Chad; Bao, Xioaqi; Badescu, Mircea; Bar-Cohen, Yoseph

    2008-01-01

    Future NASA missions are increasingly seeking to use actuators for precision positioning to accuracies of the order of fractions of a nanometer. For this purpose, multilayer piezoelectric stacks are being considered as actuators for driving these precision mechanisms. In this study, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and extreme temperatures and voltages. AC signal testing included impedance, capacitance and dielectric loss factor of each actuator as a function of the small-signal driving sinusoidal frequency, and the ambient temperature. DC signal testing includes leakage current and displacement as a function of the applied DC voltage. The applied DC voltage was increased to over eight times the manufacturers' specifications to investigate the correlation between leakage current and breakdown voltage. Resonance characterization as a function of temperature was done over a temperature range of -180C to +200C which generally exceeded the manufacturers' specifications. In order to study the lifetime performance of these stacks, five actuators from one manufacturer were driven by a 60volt, 2 kHz sine-wave for ten billion cycles. The tests were performed using a Lab-View controlled automated data acquisition system that monitored the waveform of the stack electrical current and voltage. The measurements included the displacement, impedance, capacitance and leakage current and the analysis of the experimental results will be presented.

  4. Progress Update: Stack Project Complete

    ScienceCinema

    Cody, Tom

    2016-07-12

    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.

  5. Multilayer piezoelectric stack actuator characterization

    NASA Astrophysics Data System (ADS)

    Sherrit, Stewart; Jones, Christopher M.; Aldrich, Jack B.; Blodget, Chad; Bao, Xioaqi; Badescu, Mircea; Bar-Cohen, Yoseph

    2008-03-01

    Future NASA missions are increasingly seeking to use actuators for precision positioning to accuracies of the order of fractions of a nanometer. For this purpose, multilayer piezoelectric stacks are being considered as actuators for driving these precision mechanisms. In this study, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and extreme temperatures and voltages. AC signal testing included impedance, capacitance and dielectric loss factor of each actuator as a function of the small-signal driving sinusoidal frequency, and the ambient temperature. DC signal testing includes leakage current and displacement as a function of the applied DC voltage. The applied DC voltage was increased to over eight times the manufacturers' specifications to investigate the correlation between leakage current and breakdown voltage. Resonance characterization as a function of temperature was done over a temperature range of -180°C to +200°C which generally exceeded the manufacturers' specifications. In order to study the lifetime performance of these stacks, five actuators from one manufacturer were driven by a 60volt, 2 kHz sine-wave for ten billion cycles. The tests were performed using a Lab-View controlled automated data acquisition system that monitored the waveform of the stack electrical current and voltage. The measurements included the displacement, impedance, capacitance and leakage current and the analysis of the experimental results will be presented.

  6. New Frontiers in Arctic Exploration: Autonomous Location and Sampling of Hydrothermal Vents Under the Ice at Earth's Slowest Spreading Ridge (IPY Project 173)

    NASA Astrophysics Data System (ADS)

    Edmonds, H. N.; Reves-Sohn, R.; Singh, H.; Shank, T. M.; Humphris, S.; Seewald, J.; Akin, D.; Bach, W.; Nogi, Y.; Pedersen, R.

    2006-12-01

    As part of IPY project #173, we are planning an international expedition for 2007 to locate and study hydrothermal vents on the ultraslow-spreading Gakkel Ridge, at depths greater than 4000 m beneath the permanent ice cap. This effort necessitates the development of novel exploration technologies, because the Gakkel Ridge rift valley is inaccessible to traditional deep submergence tools. With funding from NASA, NSF, and the private sector we have developed two new autonomous underwater vehicles that will find and map hydrothermal plumes in the water column, trace the buoyant plume stem to the seafloor source, and then map, photograph, and collect samples from the vent sites. The Gakkel Ridge is a key target for hydrothermal exploration not only because of its spreading rate but also because its geographic and hydrographic isolation from other portions of the mid-ocean ridge system have important implications for novel endemic vent fauna. Our major scientific themes are the geological diversity and biogeography of hydrothermal vents on the Arctic mid-ocean ridge system. Our major technology theme is autonomous exploration and sample return with an explicit mandate to develop techniques and methods for eventual use in astrobiology missions to search for life under the ice covered oceans of Europa, a moon of Jupiter. In addition to the US-led Gakkel Ridge expedition, a Norway-led expedition will target sites in seasonally ice-free water over the Mohns Ridge. The results of these two expeditions will be combined to reveal systematic patterns regarding biogeography (through both community-level and genetic-level investigations) of vent-endemic fauna, to study the differences between basalt vs. peridotite hosted vent fields, and to improve our understanding of hydrothermal circulation at ultra- slow spreading plate boundaries where amagmatic extension and long-lived faulting predominate. The expeditions will provide educational and outreach activities through the award

  7. Influence of long-term mineral fertilization on metal contents and properties of soil samples taken from different locations in Hesse, Germany

    NASA Astrophysics Data System (ADS)

    Czarnecki, S.; Düring, R.-A.

    2014-06-01

    Essential and non-essential metals occur in soils as a result of weathering, industrial processes, fertilization and atmospheric deposition. Badly adapted cultivation of agricultural soils (declining pH-value, application of unsuitable fertilizers) can enhance the mobility of metals and by the way increase their concentrations in agricultural products. The main objective of this study was to test the effects of different mineral fertilizer variations on soil properties (pH, Corg and CEC) and pseudo total and mobile metal contents of soils after 14 years of fertilizer application and to determine residual effects of the fertilization 8 years after cessation of fertilizer treatment. Soil samples were taken from a field experiment which was carried out at four different locations 210, 260, 360, and 620 m a.s.l., in Hesse, Germany. During the study, a significant decrease in soil pH and an evident increase in soil carbon content and cation exchange capacity with fertilization were determined. The CEC of the soils was closely related to their organic C contents. Moreover, pseudo and mobile metal (Cd, Cu, Mn, Pb, Zn) contents in the soils increased due to application of 14 years mineral fertilizer treatments (N, P, NP, and NPK) when compared to control plots. Fertilization is one of the major paths for metal input to agricultural soils, therefore monitoring of the long term impact of fertilization is necessary. 8 years after termination of the fertilization in the soil samples taken from soil profiles of the fertilized plots (NPK) for monitoring the residual effects of the fertilizer application, a decrease of 82.6%, 54.2%, 48.5%, 74.4%, and 56.9%, respectively, in pseudo total Cd, Cu, Mn, Pb, and Zn contents was determined.

  8. Influence of long-term mineral fertilization on metal contents and properties of soil samples taken from different locations in Hesse, Germany

    NASA Astrophysics Data System (ADS)

    Czarnecki, S.; Düring, R.-A.

    2015-01-01

    Essential and non-essential metals occur in soils as a result of weathering, industrial processes, fertilization, and atmospheric deposition. Badly adapted cultivation of agricultural soils (declining pH value, application of unsuitable fertilizers) can enhance the mobility of metals and thereby increase their concentrations in agricultural products. As the enrichment of metals in soils occurs over long time periods, monitoring of the long-term impact of fertilization is necessary to assess metal accumulation in agricultural soils. The main objective of this study was to test the effects of different mineral fertilizer variations on soil properties (pH, Corg, and cation exchange capacity (CEC)) and pseudo-total and mobile metal contents of soils after 14 years of fertilizer application and to determine residual effects of the fertilization 8 years after cessation of fertilizer treatment. Soil samples were taken from a field experiment which was carried out at four different locations (210, 260, 360, and 620 m above sea level) in Hesse, Germany. During the study, a significant decrease in soil pH and an evident increase in soil carbon content and cation exchange capacity with fertilization were determined. The CEC of the soils was closely related to their organic C contents. Moreover, pseudo- and mobile metal (Cd, Cu, Mn, Pb, Zn) contents in the soils increased due to application of 14 years of mineral fertilizer treatments (N, P, NP, and NPK) when compared to control plots. Eight years after termination of the fertilization in the soil samples taken from soil profiles of the fertilized plots (NPK) for monitoring the residual effects of the fertilizer application, a decrease of 82.6, 54.2, 48.5, 74.4, and 56.9% in pseudo-total Cd, Cu, Mn, Pb, and Zn contents, respectively, was determined.

  9. Edge-edge interactions in stacked graphene nanoplatelets

    SciTech Connect

    Cruz Silva, Eduardo; Terrones Maldonado, Humberto; Terrones Maldonado, Mauricio; Jia, Xiaoting; Sumpter, Bobby G; Dresselhaus, M; Meunier, V.

    2013-01-01

    High-resolution transmission electron microscopy (HRTEM) studies show the dynamics of small graphene platelets on larger graphene layers. The platelets move nearly freely to eventually lock in at well-defined positions close to the edges of the larger underlying graphene sheet. While such movement is driven by a shallow potential energy surface described by an interplane interaction, the lock-in position occurs by via edge-edge interactions of the platelet and the graphene surface located underneath. Here we quantitatively study this behavior using van der Waals density functional calculations. Local interactions at the open edges are found to dictate stacking configurations that are different from Bernal (AB) stacking. These stacking configurations are known to be otherwise absent in edge-free two-dimensional (2D) graphene. The results explain the experimentally observed platelet dynamics and provide a detailed account of the new electronic properties of these combined systems.

  10. High performance zinc air fuel cell stack

    NASA Astrophysics Data System (ADS)

    Pei, Pucheng; Ma, Ze; Wang, Keliang; Wang, Xizhong; Song, Mancun; Xu, Huachi

    2014-03-01

    A zinc air fuel cell (ZAFC) stack with inexpensive manganese dioxide (MnO2) as the catalyst is designed, in which the circulation flowing potassium hydroxide (KOH) electrolyte carries the reaction product away and acts as a coolant. Experiments are carried out to investigate the characteristics of polarization, constant current discharge and dynamic response, as well as the factors affecting the performance and uniformity of individual cells in the stack. The results reveal that the peak power density can be as high as 435 mW cm-2 according to the area of the air cathode sheet, and the influence factors on cell performance and uniformity are cell locations, filled state of zinc pellets, contact resistance, flow rates of electrolyte and air. It is also shown that the time needed for voltages to reach steady state and that for current step-up or current step-down are both in milliseconds, indicating the ZAFC can be excellently applied to vehicles with rapid dynamic response demands.

  11. Hamiltonian approach to slip-stacking dynamics

    DOE PAGES

    Lee, S. Y.; Ng, K. Y.

    2017-06-29

    Hamiltonian dynamics has been applied to study the slip-stacking dynamics. The canonical-perturbation method is employed to obtain the second-harmonic correction term in the slip-stacking Hamiltonian. The Hamiltonian approach provides a clear optimal method for choosing the slip-stacking parameter and improving stacking efficiency. The dynamics are applied specifically to the Fermilab Booster-Recycler complex. As a result, the dynamics can also be applied to other accelerator complexes.

  12. Remote System for Characterizing, Monitoring and Inspecting the Inside of Contaminated Nuclear Stacks

    SciTech Connect

    Vargas, Mario; Mendez, William; Lagos, Dr. Leonel; Lind, Randall F; Lloyd, Peter D; Rowe, John C; Noakes, Mark W; Pin, Francois G

    2011-01-01

    The Stack Characterization System (SCS) is a collaborative project with the Robotics and Energetic Systems Group (RESG) at Oak Ridge National Laboratory (ORNL) and the Applied Research Center (ARC) at Florida International University (FIU). The SCS is a robotic system that will be deployed into off-gas stacks located around the central campus at ORNL. The system will consists of surveying equipment capable of taking surface contamination samples, radiation readings, core samples and transmit live video to its operators. Trade studies were conducted on varying concrete materials to determine the best way of retrieving loose contamination from the surface. The studies were performed at the ARC facility by DOE Fellows, where traditional cloth wipes were compared to adhesive material. The adhesive material was tested on the RESG s smear sampler to record how much loose surface material could be retrieved. The DOE Fellows completed a summer internship during which conceptual designs were created for a deployable radiation detector and core drill capable of retrieving multiple core samples.

  13. Helping Students Design HyperCard Stacks.

    ERIC Educational Resources Information Center

    Dunham, Ken

    1995-01-01

    Discusses how to teach students to design HyperCard stacks. Highlights include introducing HyperCard, developing storyboards, introducing design concepts and scripts, presenting stacks, evaluating storyboards, and continuing projects. A sidebar presents a HyperCard stack evaluation form. (AEF)

  14. 49 CFR 178.980 - Stacking test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Stacking test. 178.980 Section 178.980... Packagings § 178.980 Stacking test. (a) General. The stacking test must be conducted for the qualification of... test. (1) All Large Packagings except flexible Large Packaging design types must be loaded to...

  15. Precision Cosmography with Stacked Voids

    NASA Astrophysics Data System (ADS)

    Lavaux, Guilhem; Wandelt, Benjamin D.

    2012-08-01

    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-Paczyński (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.

  16. PRECISION COSMOGRAPHY WITH STACKED VOIDS

    SciTech Connect

    Lavaux, Guilhem; Wandelt, Benjamin D.

    2012-08-01

    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.

  17. Boiler Stack Gas Heat Recovery

    DTIC Science & Technology

    1987-09-01

    Based upon "economic analysis of available options, three cost- effective methods of recovering waste heat were identified: the conventional economizer...upon economic analysis of available options, three cost- effective methods of Continued DO I IA.N1 1473 EDITION OF I NOV AS IS OBSOLETE S Y C O OF...energy loss in a boiler is attributable to the hot flue gas leaving the stack. Thus, the most effective method to save fuel is to recover as much

  18. Stack Monitor Operating Experience Review

    SciTech Connect

    L. C. Cadwallader; S. A. Bruyere

    2009-05-01

    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.

  19. Piezoelectric stack transducer evaluation and comparison for optimized energy harvesting

    NASA Astrophysics Data System (ADS)

    Gamboa, Bryan

    Lead Zirconate Titanate (PZT) is the most prevalent piezoelectric material used around the world. These materials are used in a wide array of devices across a vast group of applications. The primary focus of this research is on the application and optimization of direct piezoelectric effect in energy harvesting from low frequency mechanical vibration. The specific research aim is at understanding the stacked PZT transducers in their mechanisms and performance on effective electromechanical energy conversion. Piezoelectric power output has been determined based on understanding of the fundamental concepts in composites (1:3 bi-phasic) and stack transducers. Several property structure relations are evaluated by various experimental methods including the utilization of electrodynamic test systems (Acumen III and the Universal Testing Machine 25, both by MTS Systems Corp.). The converted power is monitored and recorded using pc interfaced digital multimeter (Metrahit by Messtechnik GmbH). Power evaluation is compared among several samples in order to understand the most efficient configuration utilizing PZT ceramics. Impedance measurements, piezoelectric coefficients and permittivity calculations are evaluated to more accurately compare the samples. Power density as function of applied mechanical force and pressure, are calculated and compared with experimental results which yield good agreement. Three types of stack PZT transducers were compared and systemically tested for their electromechanical power conversion performance. While 1:3 composite stack PZT transducer was found to be the best performer in term of power density per active volume, the custom fabricated stack PZT transducers (UTSA stack sample) were found to have the highest power density per total transducer volume, 0.615 muW/mm3, measured at 965 kN/m2 (140 PSI), among the three types studied.

  20. Stacks

    ERIC Educational Resources Information Center

    Kimber, Lizzie

    2010-01-01

    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…

  1. Velocity model optimization for surface microseismic monitoring via amplitude stacking

    NASA Astrophysics Data System (ADS)

    Jiang, Haiyu; Wang, Zhongren; Zeng, Xiaoxian; Lü, Hao; Zhou, Xiaohua; Chen, Zubin

    2016-12-01

    A usable velocity model in microseismic projects plays a crucial role in achieving statistically reliable microseismic event locations. Existing methods for velocity model optimization rely mainly on picking arrival times at individual receivers. However, for microseismic monitoring with surface stations, seismograms of perforation shots have such low signal-to-noise ratios (S/N) that they do not yield sufficiently reliable picks. In this study, we develop a framework for constructing a 1-D flat-layered a priori velocity model using a non-linear optimization technique based on amplitude stacking. The energy focusing of the perforation shot is improved thanks to very fast simulated annealing (VFSA), and the accuracies of shot relocations are used to evaluate whether the resultant velocity model can be used for microseismic event location. Our method also includes a conventional migration-based location technique that utilizes successive grid subdivisions to improve computational efficiency and source location accuracy. Because unreasonable a priori velocity model information and interference due to additive noise are the major contributors to inaccuracies in perforation shot locations, we use velocity model optimization as a compensation scheme. Using synthetic tests, we show that accurate locations of perforation shots can be recovered to within 2 m, even with pre-stack S/N ratios as low as 0.1 at individual receivers. By applying the technique to a coal-bed gas reservoir in Western China, we demonstrate that perforation shot location can be recovered to within the tolerance of the well tip location.

  2. Location Privacy

    NASA Astrophysics Data System (ADS)

    Meng, Xiaofeng; Chen, Jidong

    With rapid development of sensor and wireless mobile devices, it is easy to access mobile users' location information anytime and anywhere. On one hand, LBS is becoming more and more valuable and important. On the other hand, location privacy issues raised by such applications have also gained more attention. However, due to the specificity of location information, traditional privacy-preserving techniques in data publishing cannot be used. In this chapter, we will introduce location privacy, and analyze the challenges of location privacy-preserving, and give a survey of existing work including the system architecture, location anonymity and query processing.

  3. Engineering discrete stacks of aromatic molecules.

    PubMed

    Klosterman, Jeremy K; Yamauchi, Yoshihiro; Fujita, Makoto

    2009-06-01

    Intrigued by transannular interactions occurring in stacked aromatic molecules, chemists have long endeavored to engineer discrete stacks of specific lengths and orientation. The maturation of self-assembly methodologies has shifted the focus away from utilizing covalent scaffolds to harnessing non-covalent interactions such as ionic interactions, hydrogen bonds, metal-ligand interactions, and aromatic interactions. Aromatic molecules often assemble into ill-defined, infinite aggregates and thus multiple self-assembly techniques must be combined to achieve the desired stack size and conformations. This critical review briefly highlights covalent scaffolds of stack aromatics before focusing on modern self-assembly based strategies for engineering discrete stacks of aromatic molecules (149 references).

  4. Location | FNLCR

    Cancer.gov

    The Frederick National Laboratory for Cancer Research campus is located 50 miles northwest of Washington, D.C., and 50 miles west of Baltimore, Maryland, in Frederick, Maryland. Satellite locations include leased and government facilities extending s

  5. Map of Western Copper River Basin, Alaska, Showing Lake Sediments and Shorelines, Glacial Moraines, and Location of Stratigraphic Sections and Radiocarbon-Dated Samples

    USGS Publications Warehouse

    Williams, John R.; Galloway, John P.

    1986-01-01

    The purpose of this report is to make available basic data on radiocarbon dating of 61 organic samples from 40 locations in the western Copper River Basin and adjacent uplands and in the uppermost Matanuska River Valley. The former distribution of late Quaternary glacial lakes and of glaciers as mapped from field work and photo interpretation is provided as background for interpretation of the radiocarbon dates and are the basic data needed for construction of the late Quaternary chronology. The glacial boundaries, formed and expressed by moraines, ice-contact margins, marginal channels, deltas, and other features, are obscured by a drape of glaciolacustrine deposits in a series of glacial lakes. The highest lake, represented by bottom sediments as high as 914 m to 975 m above sea level, extends from Fog Lakes lowland on Susitna River upstream into the northwestern part of the Copper River Basin (the part now draining to Susitna River) where it apparently was held in by an ice border. It was apparently dammed by ice from the Mt. McKinley area, by Talkeetna G1acier, and may have had a temporary drainage threshold at the headwaters of Chunilna Creek. No shorelines have been noted within the map area, although Nichols and Yehle (1961) reported shorelines within the 914-975 m range in the Denali area to the north of that mapped. Recent work by geologic consultants for the Susitna Hydroelectric Project has confirmed the early inferences (Karlstrom, 1964) about the existence of a lake in the Susitna canyon, based originally on drilling by the Bureau of Reclamation about 35 years ago. According to dating of deposits at Tyone Bluff (map locations 0, P), Thorson and others (1981) concluded that a late Wisconsin advance of the glaciers between 11,535 and 21,730 years ago was followed by a brief interval of lacustrine sedimentation, and was preceded by a long period of lake deposition broken by a lowering of the lake between 32,000 and about 25,000 years ago. An alternate

  6. Edge magnetization in Bernal-stacked trilayer zigzag graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Pérez, Juan Antonio Casao

    2016-06-01

    We have used a tight-binding Hamiltonian of an ABA-stacked trilayer zigzag graphene nanoribbon with β-alignment edges to study the edge magnetizations. Our model includes the effect of the intralayer next-nearest-neighbor hopping, the interlayer hopping responsible for the trigonal warping and the interaction between electrons, which is considered by a single band Hubbard model in the mean field approximation. Firstly, in the neutral system we analyzed the two magnetic states in which both edge magnetizations reach their maximum value; the first one is characterized by an intralayer ferromagnetic coupling between the magnetizations at opposite edges, whereas in the second state that coupling is antiferromagnetic. The band structure, the location of the edge-state bands and the local density of states resolved in spin are calculated in order to understand the origins of the edge magnetizations. We have also introduced an electron doping so that the number of electrons in the ribbon unit cell is higher than in neutral case. As a consequence, we have obtained magnetization steps and charge accumulation at the edges of the sample, which are caused by the edge-state flat bands.

  7. Glass transition dynamics of stacked thin polymer films

    NASA Astrophysics Data System (ADS)

    Fukao, Koji; Terasawa, Takehide; Oda, Yuto; Nakamura, Kenji; Tahara, Daisuke

    2011-10-01

    The glass transition dynamics of stacked thin films of polystyrene and poly(2-chlorostyrene) were investigated using differential scanning calorimetry and dielectric relaxation spectroscopy. The glass transition temperature Tg of as-stacked thin polystyrene films has a strong depression from that of the bulk samples. However, after annealing at high temperatures above Tg, the stacked thin films exhibit glass transition at a temperature almost equal to the Tg of the bulk system. The α-process dynamics of stacked thin films of poly(2-chlorostyrene) show a time evolution from single-thin-film-like dynamics to bulk-like dynamics during the isothermal annealing process. The relaxation rate of the α process becomes smaller with increase in the annealing time. The time scale for the evolution of the α dynamics during the annealing process is very long compared with that for the reptation dynamics. At the same time, the temperature dependence of the relaxation time for the α process changes from Arrhenius-like to Vogel-Fulcher-Tammann dependence with increase of the annealing time. The fragility index increases and the distribution of the α-relaxation times becomes smaller with increase in the annealing time for isothermal annealing. The observed change in the α process is discussed with respect to the interfacial interaction between the thin layers of stacked thin polymer films.

  8. The view from the boundary: a new void stacking method

    NASA Astrophysics Data System (ADS)

    Cautun, Marius; Cai, Yan-Chuan; Frenk, Carlos S.

    2016-04-01

    We introduce a new method for stacking voids and deriving their profile that greatly increases the potential of voids as a tool for precision cosmology. Given that voids are distinctly non-spherical and have most of their mass at their edge, voids are better described relative to their boundary rather than relative to their centre, as in the conventional spherical stacking approach. The boundary profile is obtained by computing the distance of each volume element from the void boundary. Voids can then be stacked and their profiles computed as a function of this boundary distance. This approach enhances the weak lensing signal of voids, both shear and convergence, by a factor of 2 when compared to the spherical stacking method. It also results in steeper void density profiles that are characterized by a very slow rise inside the void and a pronounced density ridge at the void boundary. The resulting boundary density profile is self-similar when rescaled by the thickness of the density ridge, implying that the average rescaled profile is independent of void size. The boundary velocity profile is characterized by outflows in the inner regions whose amplitude scales with void size, and by a strong inflow into the filaments and walls delimiting the void. This new picture enables a straightforward discrimination between collapsing and expanding voids both for individual objects as well as for stacked samples.

  9. Lightweight Stacks of Direct Methanol Fuel Cells

    NASA Technical Reports Server (NTRS)

    Narayanan, Sekharipuram; Valdez, Thomas

    2004-01-01

    An improved design concept for direct methanol fuel cells makes it possible to construct fuel-cell stacks that can weigh as little as one-third as much as do conventional bipolar fuel-cell stacks of equal power. The structural-support components of the improved cells and stacks can be made of relatively inexpensive plastics. Moreover, in comparison with conventional bipolar fuel-cell stacks, the improved fuel-cell stacks can be assembled, disassembled, and diagnosed for malfunctions more easily. These improvements are expected to bring portable direct methanol fuel cells and stacks closer to commercialization. In a conventional bipolar fuel-cell stack, the cells are interspersed with bipolar plates (also called biplates), which are structural components that serve to interconnect the cells and distribute the reactants (methanol and air). The cells and biplates are sandwiched between metal end plates. Usually, the stack is held together under pressure by tie rods that clamp the end plates. The bipolar stack configuration offers the advantage of very low internal electrical resistance. However, when the power output of a stack is only a few watts, the very low internal resistance of a bipolar stack is not absolutely necessary for keeping the internal power loss acceptably low.

  10. Hen eggwhite-mediated stack crystallization of calcium carbonate

    NASA Astrophysics Data System (ADS)

    Hu, Yanli; Ma, Yongjun; Zhou, Yong; Nie, Fude; Duan, Xiaohui; Pei, Chonghua

    2010-03-01

    In this paper, the stack-like crystallization of calcium carbonate in the presence of hen eggwhite under direct drying and vacuum freeze drying was investigated, and marked morphological changes in the calcium carbonate particles were observed depending on the reaction condition used. Scanning electron microscopy (SEM), Powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Transmission electron microscopy (TEM), and Nano Mechanical Tester were employed to characterize the samples. Results indicate that gelling eggwhite-mediated the formation of the "stack-like" layered calcium carbonate aggregates composed of considerable nanosheets under direct drying while only rhombohedra calcite crystal (1 0 4) was formed without any additives. An analogous structure to the brick-and-mortar arrangement was attainted by vacuum freeze drying. The average elastic modulus and the hardness of "stack-like" calcium carbonate hybrid material were assessed 0.9952 and 0.0415 GPa with Nano-indenter test, respectively.

  11. Analyzing Stack Flows to Compare Java Programs

    NASA Astrophysics Data System (ADS)

    Lim, Hyun-Il; Han, Taisook

    This paper presents a method for comparing and detecting clones of Java programs by analyzing program stack flows. A stack flow denotes an operational behavior of a program by describing individual instructions and stack movements for performing specific operations. We analyze stack flows by simulating the operand stack movements during execution of a Java program. Two programs for detection of clones of Java programs are compared by matching similar pairs of stack flows in the programs. Experiments were performed on the proposed method and compared with the earlier approaches of comparing Java programs, the Tamada, k-gram, and stack pattern based methods. Their performance was evaluated with real-world Java programs in several categories collected from the Internet. The experimental results show that the proposed method is more effective than earlier methods of comparing and detecting clones of Java programs.

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

    PubMed

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

    1975-01-01

    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.

  13. Structure Of Ice Crystallized From Supercooled Water: Stacking Disordered Ice

    NASA Astrophysics Data System (ADS)

    Malkin, T. L.; Murray, B. J.; Brukhno, A.; Anwar, J.; Salzmann, C.

    2012-12-01

    At atmospheric pressures ice is thought to exist in two well defined crystalline forms: stable hexagonal ice and metastable cubic ice. A metastable form of ice is thought to form in the atmosphere [1] Using X-ray diffraction data and Monte Carlo simulations; we show that ice that crystallizes both homogeneously and heterogeneously from supercooled water adopts neither of these two phases. The resulting ice is disordered in one dimension and consequently does not possess either cubic or hexagonal symmetry. It is instead composed of randomly stacked layers of cubic and hexagonal sequences. We refer to this ice as stacking-disordered ice I (ice Isd ) [2]. While similar stacking disorder has been reported before, such observations have been restricted to either samples re-crystallised from high-pressure ice phases [3] or ice formation in mesopores [4]. Review of the literature reveals that almost all ice previously identified as cubic ice in diffraction studies, which have used an array of methodologies to generate the ice, were most likely stacking-disordered ice I with varying degrees of stacking disorder. Our results suggest that the initial phase of ice formed when water freezes is the metastable stacking-disordered ice I which forms independent of the method of nucleation. Stacking-disordered ice may be the kinetic product, i.e. the material which forms fastest. Accordingly, we suggest that stacking-disordered ice is always the phase to crystallise when water freezes. In many situations it will relax to the stable hexagonal phase with time. Stacking-disordered ice may persist in the colder parts of the atmosphere and form irregular or rough crystals similar to many smaller quasi spherical ice crystals observed in the earth's atmosphere. [1] B. J. Murray et al., Nature, 2005, 434, 202-205 [2] T. L. Malkin et al., PNAS, 2012, 109 (4): 1041 - 1045 [3] T. C. Hansen et al., J. Phys. Condens. Matter, 2008, 20, 285105. [4] K. Morishige et al., J. Phys. Chem. C, 2009, 113

  14. Stacking the odds for Golgi cisternal maturation

    PubMed Central

    Mani, Somya; Thattai, Mukund

    2016-01-01

    What is the minimal set of cell-biological ingredients needed to generate a Golgi apparatus? The compositions of eukaryotic organelles arise through a process of molecular exchange via vesicle traffic. Here we statistically sample tens of thousands of homeostatic vesicle traffic networks generated by realistic molecular rules governing vesicle budding and fusion. Remarkably, the plurality of these networks contain chains of compartments that undergo creation, compositional maturation, and dissipation, coupled by molecular recycling along retrograde vesicles. This motif precisely matches the cisternal maturation model of the Golgi, which was developed to explain many observed aspects of the eukaryotic secretory pathway. In our analysis cisternal maturation is a robust consequence of vesicle traffic homeostasis, independent of the underlying details of molecular interactions or spatial stacking. This architecture may have been exapted rather than selected for its role in the secretion of large cargo. DOI: http://dx.doi.org/10.7554/eLife.16231.001 PMID:27542195

  15. Status of MCFC stack development at Hitachi

    SciTech Connect

    Takashima, S.; Kahara, T.; Takeuchi, M.

    1996-12-31

    Hitachi, Ltd. has been developing Molten Carbonate Fuel Cells in the New Sunshine project in Japan, and Hitachi is taking part in the development of 1,000kW MCFC pilot plant at Kawagoe. Hitachi is engaged in system planning of the 1,000kW pilot plant, design and manufacturing of the reformer subsystem and the fuel cell subsystem, and design and manufacturing of the 250kW stacks for the 1,000kW plant. The 250kW stacks are developed on the basis of the results of the 100kW stack in 1993 and the following 25kW stack in 1994. In parallel to the stack development, Hitachi is also conducting researches for long endurance cells and stacks. In addition to the researches for anode, cathode, electrolyte, and electrolyte matrix, improvement of temperature distribution in stacks is investigated to extend the stack life. This paper describes the planning status of the 250kW stacks for the 1,000kW MCFC plant and the developing status of stack cooling method for longer life.

  16. Stacked subsea templates accelerate deepwater development

    SciTech Connect

    Ramsey, J.F.; Blincow, R.M.; Pickard, R.D. )

    1991-10-21

    This paper reports on a deepwater project that can be brought on-line more quickly because of stackable drilling and production templates. Historically, one of the primary barriers to the economic development of deepwater reserves has been the long lead time from discovery to first production. Typically, production facilities must be built and often installed before development wells are drilled. The use of three-slot drilling templates allows development drilling to proceed while the production templates, Christmas trees, flow lines, and production platform are constructed. Thus, the time from initial investment to first revenue reduced. Enserch Exploration Inc., along with partners Petrofina Delaware Inc. and AGIP Petroleum, is using a piggy-back or transportable stacked template system to develop deepwater gas reserves in Mississippi Canyon Block 441, approximately 50 miles south of Grand Isle, La. The discovery is located in 1,410-1,520 ft of water. The Louisiana Offshore Oil Port (LOOP) safety fairway running north to south covers the eastern three fourths of Mississippi Canyon Block 441 and rules out surface production facilities over the well locations.

  17. FAST TRACK PAPER: Resolving crustal thickness using SS waveform stacks

    NASA Astrophysics Data System (ADS)

    Rychert, Catherine A.; Shearer, Peter M.

    2010-03-01

    We image lithospheric interfaces using variations in the character of SS waveform stacks, a method we term SS Lithospheric Interface Profiling (SSLIP). The variations are caused by reflected phases, that is, underside reflections (SS precursors) and topside multiples (SS reverberations), created at velocity discontinuities near the midpoint of the SS ray path. Stacks from continental versus oceanic bounce point regions produce distinctly different SS waveforms, consistent with the large continent/ocean difference in crustal thickness. To investigate the potential of SS waveform stacks to constrain Moho depths under continents, we develop a method to fit continental bounce point stacks with a reference SS waveform convolved with a crustal operator. The SSLIP inferred Moho depths agree with the CRUST 2.0 model in Asia for those regions where the SS bounce point density is the highest. The SSLIP depths are correlated (correlation coefficient 0.82) with the CRUST 2.0 values averaged over sample bins of 10° radius. The SSLIP method has broad lateral resolution in comparison to most other methods for resolving crustal thickness, but has the potential to sample regions where station coverage may be sparse.

  18. T phase observations in global seismogram stacks

    NASA Astrophysics Data System (ADS)

    Buehler, J. S.; Shearer, P. M.

    2015-08-01

    The T phase, conversion of acoustic to seismic energy, is typically observed as a high-frequency wave train at hydrophones or coastal seismic stations. Here we show that the T phase can be observed in broadband waveform stacks of ˜5200 earthquakes recorded by the Global Seismic Network. To enhance the phase arrivals in stacks, we apply short-time window average over long-time window average filtering to individual traces before stacking. Although the T phase arrival is visible in stacks from seismograms filtered at 0.5-5 Hz, it appears much stronger at higher frequencies (2-8 Hz) and is further enhanced by only stacking seismograms from oceanic paths. Stacking only subsets of the data depending on continental path lengths on the receiver side shows that the T phase can be observed at stations up to 4∘ inland from the coast, and changes in the T phase arrival time correspond to reasonable crustal velocities.

  19. Prediction of temperature profile in MCFC stack

    SciTech Connect

    Lee, Kab Soo; Kim, Hwayong; Hong, Seong-An; Lim, Hee Chun

    1996-12-31

    A simple three dimensional model was developed to simulate the temperature distribution and the performance of various flow types of the MCFC stack. The objective of this study was to understand the complicated phenomena occurring in the MCFC stack and to supply the basic data for optimizing the operating condition of the MCFC stack. Assuming that the stack consists of a number of differential elements which have uniform temperature and gas composition, the model was solved by finite difference method. The performance of this model was demonstrated by comparing the calculated value with experimental data of the 1.5kW class co-flow type MCFC stack operated in KIST. This model can be utilized as a simple diagnostic tool in case of the operational abnormality such as the hot spot which often occurs inside the stack.

  20. Ultra-dark graphene stack metamaterials

    NASA Astrophysics Data System (ADS)

    Chugh, Sunny; Man, Mengren; Chen, Zhihong; Webb, Kevin J.

    2015-02-01

    We present a fabrication method to achieve a graphene stack metamaterial, a periodic array of unit cells composed of graphene and a thin insulating spacer, that allows accumulation of the strong absorption from individual graphene sheets and low reflectivity from the stack. The complex sheet conductivity of graphene from experimental data models the measured power transmitted as a function of wavelength and number of periods in the stack. Simulated results based on the extracted graphene complex sheet conductivity for thicker stacks suggest that the graphene stack reflectivity and the per-unit-length absorption can be controlled to exceed the performance of competing light absorbers. Furthermore, the electrical properties of graphene coupled with the stack absorption characteristics provide for applications in optoelectronic devices.

  1. Complex and noncentrosymmetric stacking of layered metal dichalcogenide materials created by screw dislocations

    DOE PAGES

    Shearer, Melinda J.; Samad, Leith; Zhang, Yi; ...

    2017-02-08

    The interesting and tunable properties of layered metal dichalcogenides heavily depend on their phase and layer stacking. Here, we show and explain how the layer stacking and physical properties of WSe2 are influenced by screw dislocations. A one-to-one correlation of atomic force microscopy and high- and low-frequency Raman spectroscopy of many dislocated WSe2 nanoplates reveals variations in the number and shapes of dislocation spirals and different layer stackings that are determined by the number, rotation, and location of the dislocations. Plates with triangular dislocation spirals form noncentrosymmetric stacking that gives rise to strong second-harmonic generation and enhanced photoluminescence, plates withmore » hexagonal dislocation spirals form the bulk 2H layer stacking commonly observed, and plates containing mixed dislocation shapes have intermediate noncentrosymmetric stackings with mixed properties. Multiple dislocation cores and other complexities can lead to more complex stackings and properties. Finally, these previously unobserved properties and layer stackings in WSe2 will be interesting for spintronics and valleytronics.« less

  2. Complex and Noncentrosymmetric Stacking of Layered Metal Dichalcogenide Materials Created by Screw Dislocations.

    PubMed

    Shearer, Melinda J; Samad, Leith; Zhang, Yi; Zhao, Yuzhou; Puretzky, Alexander; Eliceiri, Kevin W; Wright, John C; Hamers, Robert J; Jin, Song

    2017-03-08

    The interesting and tunable properties of layered metal dichalcogenides heavily depend on their phase and layer stacking. Here, we show and explain how the layer stacking and physical properties of WSe2 are influenced by screw dislocations. A one-to-one correlation of atomic force microscopy and high- and low-frequency Raman spectroscopy of many dislocated WSe2 nanoplates reveals variations in the number and shapes of dislocation spirals and different layer stackings that are determined by the number, rotation, and location of the dislocations. Plates with triangular dislocation spirals form noncentrosymmetric stacking that gives rise to strong second-harmonic generation and enhanced photoluminescence, plates with hexagonal dislocation spirals form the bulk 2H layer stacking commonly observed, and plates containing mixed dislocation shapes have intermediate noncentrosymmetric stackings with mixed properties. Multiple dislocation cores and other complexities can lead to more complex stackings and properties. These previously unobserved properties and layer stackings in WSe2 will be interesting for spintronics and valleytronics.

  3. Manifold seal for fuel cell stack assembly

    DOEpatents

    Schmitten, Phillip F.; Wright, Maynard K.

    1989-01-01

    An assembly for sealing a manifold to a stack of fuel cells includes a first resilient member for providing a first sealing barrier between the manifold and the stack. A second resilient member provides a second sealing barrier between the manifold and the stack. The first and second resilient members are retained in such a manner as to define an area therebetween adapted for retaining a sealing composition.

  4. Improvement of Phosphoric Acid Fuel Cell Stacks.

    DTIC Science & Technology

    1980-07-01

    cell stacks. Stack assembly techniques using both prefilled and dry matrices with wick filling were employed with equally good results. Phenolic fiber...matrix to provide edge sealing, with no cement being used (except to position the electrodes on the bipolar plate). The stack is assembled with prefilled ...used in the wet assembly technique. Prior to use, the acid is heated to 170 0F. Next, 16 to 20 ml of acid is applied by syringe uniformly over the 5 in

  5. Hydrogen Embrittlement And Stacking-Fault Energies

    NASA Technical Reports Server (NTRS)

    Parr, R. A.; Johnson, M. H.; Davis, J. H.; Oh, T. K.

    1988-01-01

    Embrittlement in Ni/Cu alloys appears related to stacking-fault porbabilities. Report describes attempt to show a correlation between stacking-fault energy of different Ni/Cu alloys and susceptibility to hydrogen embrittlement. Correlation could lead to more fundamental understanding and method of predicting susceptibility of given Ni/Cu alloy form stacking-fault energies calculated from X-ray diffraction measurements.

  6. Donor–acceptor stacking arrangements in bulk and thin-film high-mobility conjugated polymers characterized using molecular modelling and MAS and surface-enhanced solid-state NMR spectroscopy† †Electronic supplementary information (ESI) available: Additional computational and experimental details, including the DNP sample preparation. See DOI: 10.1039/c7sc00053g Click here for additional data file.

    PubMed Central

    Chaudhari, Sachin R.; Broch, Katharina; Lesage, Anne; Lemaur, Vincent; Dudenko, Dmytro; Olivier, Yoann; Sirringhaus, Henning; Emsley, Lyndon; Grey, Clare P.

    2017-01-01

    Conjugated polymers show promising properties as cheap, sustainable and solution-processable semiconductors. A key challenge in the development of these materials is to determine the polymer chain structure, conformation and packing in both the bulk polymer and in thin films typically used in devices. However, many characterisation techniques are unable to provide atomic-level structural information owing to the presence of disorder. Here, we use molecular modelling, magic-angle spinning (MAS) and dynamic nuclear polarisation surface-enhanced NMR spectroscopy (DNP SENS) to characterise the polymer backbone group conformations and packing arrangement in the high-mobility donor–acceptor copolymer diketopyrrolo-pyrrole-dithienylthieno[3,2-b]thiophene (DPP-DTT). Using conventional 1H and 13C solid-state MAS NMR coupled with density functional theory calculations and molecular dynamics simulations, we find that the bulk polymer adopts a highly planar backbone conformation with a laterally-shifted donor-on-acceptor stacking arrangement. DNP SENS enables acquisition of 13C NMR data for polymer films, where sensitivity is limiting owing to small sample volumes. The DNP signal enhancement enables a two-dimensional 1H–13C HETCOR spectrum to be recorded for a drop-cast polymer film, and a 13C CPMAS NMR spectrum to be recorded for a spin-coated thin-film with a thickness of only 400 nm. The results show that the same planar backbone structure and intermolecular stacking arrangement is preserved in the films following solution processing and annealing, thereby rationalizing the favourable device properties of DPP-DTT, and providing a protocol for the study of other thin film materials. PMID:28507688

  7. Film stacking architecture for immersion lithography process

    NASA Astrophysics Data System (ADS)

    Goto, Tomohiro; Sanada, Masakazu; Miyagi, Tadashi; Shigemori, Kazuhito; Kanaoka, Masashi; Yasuda, Shuichi; Tamada, Osamu; Asai, Masaya

    2008-03-01

    In immersion lithography process, film stacking architecture will be necessary due to film peeling. However, the architecture will restrict lithographic area within a wafer due to top side EBR accuracy In this paper, we report an effective film stacking architecture that also allows maximum lithographic area. This study used a new bevel rinse system on RF3 for all materials to make suitable film stacking on the top side bevel. This evaluation showed that the new bevel rinse system allows the maximum lithographic area and a clean wafer edge. Patterning defects were improved with suitable film stacking.

  8. ooi: OpenStack OCCI interface

    NASA Astrophysics Data System (ADS)

    López García, Álvaro; Fernández del Castillo, Enol; Orviz Fernández, Pablo

    In this document we present an implementation of the Open Grid Forum's Open Cloud Computing Interface (OCCI) for OpenStack, namely ooi (Openstack occi interface, 2015) [1]. OCCI is an open standard for management tasks over cloud resources, focused on interoperability, portability and integration. ooi aims to implement this open interface for the OpenStack cloud middleware, promoting interoperability with other OCCI-enabled cloud management frameworks and infrastructures. ooi focuses on being non-invasive with a vanilla OpenStack installation, not tied to a particular OpenStack release version.

  9. Flexible interconnects for fuel cell stacks

    DOEpatents

    Lenz, David J.; Chung, Brandon W.; Pham, Ai Quoc

    2004-11-09

    An interconnect that facilitates electrical connection and mechanical support with minimal mechanical stress for fuel cell stacks. The interconnects are flexible and provide mechanically robust fuel cell stacks with higher stack performance at lower cost. The flexible interconnects replace the prior rigid rib interconnects with flexible "fingers" or contact pads which will accommodate the imperfect flatness of the ceramic fuel cells. Also, the mechanical stress of stacked fuel cells will be smaller due to the flexibility of the fingers. The interconnects can be one-sided or double-sided.

  10. Self – Reported Depression, Anxiety and Evaluation of Own Pain in Clinical Sample of Patients with Different Location of Chronic Pain

    PubMed Central

    RUS MAKOVEC, Maja; VINTAR, Neli; MAKOVEC, Samo

    2015-01-01

    Background Depression, anxiety and chronic pain are frequent co-occurrent disorders. Patients with these mental disorders experience more intense pain that lasts for a longer time. Method Questionnaire with 228 variables was applied to 109 randomly chosen patients that were treated at an outpatient clinic for treatment of chronic pain of the University Clinical Centre Ljubljana from March to June 2013. 87 patients responded to the questionnaire (79.8%). Location of pain considering diagnosis was the criterion in the discriminant analysis (soft tissue disorders; headache; symptoms not elsewhere classified; back pain) and following summative scores as predictors: level of depression and anxiety (The Zung Self-Rating Depression/Anxiety Scale), evaluation of pain and perceptions of being threatened in social relations. Results Average age of participants was M = 52.7 years (SD 13.9), with 70.9% female, 29.1% male participants. 63% of respondents achieved clinically important level of depression and 54% clinically important level of anxiety. On univariate level, the highest level of depression and anxiety was found for back pain and the lowest for headache. No significant difference was found in evaluation of pain and perceptions of being threatened in social relations regarding location of pain. Self-evaluation of depression has, in the framework of discriminant analysis, the largest weight for prediction of differentiation between different locations of pain. Conclusion Different locations of pain have different connections with mood levels. The results of research on a preliminary level indicate the need to consider mental experience in the treatment of chronic pain. PMID:27646616

  11. Cycle stacking and long-term sea-level history in the Lower Cretaceous (Gavrovo Platform, NW Greece)

    SciTech Connect

    Groetsch, J.

    1996-07-01

    The stacking pattern of peritidal shallowing-upward cycles of a continuously exposed Barremian to upper Albian section from an isolated carbonate platform in the Gavrovo-Tripolitza Zone (NW Greece) has been analyzed. The 541 m thick succession is located in an intraplatform setting with an overall mud-dominated facies development. It comprises 252 peritidal cycles, which show a systematic increase in cycle thickness from the Barremian to Albian. Comparison of the cycle stacking pattern of the section, which spans 35 m.y., and several published curves of long-term eustatic sea-level history show striking similarities. Comparison of cycle stacking pattern in Greece with a time-equivalent section measured near Potrero Garcia in Mexico suggests preservation of similar trends in Fischer plots in the two areas even though a difference in mean cycle thickness indicates different rates of subsidence in Greece and Mexico. This implies that the shallow-water carbonates of the Gavrovo platform are recording second-order eustatic sea-level variations. Closely spaced samples throughout the section allow evaluation of the degree of early diagenetic alteration of depositional facies within the shallowing-upward cycles. The degree of vadose diagenetic overprinting of intertidal and subtidal facies and multiple overprinting of individual cycles support a predominantly allocyclic control of deposition by low-amplitude, high-frequency sea-level fluctuations during Early Cretaceous greenhouse climate.

  12. Performance evaluation of PEFC stack

    SciTech Connect

    Fujita, Jun-ichi; Ohtsuki, Jitsuji; Shindo, Yoshihiko

    1996-12-31

    Polymer electrolyte fuel cells (PEFCs) have many advantages such as high current density, short start-up time and endurance for start-stop cycles. Making use of these advantages, Fuji Electric has been working with the Kansai Electric Power Co., Inc. to explore practical applications of PEFCs for an electric utility use. Since large-sized electrodes are required in the electric utility applications, we have fabricated 600cm{sup 2} membrane-electrode assemblies by using hot-press method. We have also designed a cell structure to realize a uniform reaction over the electrodes. The structure includes a properly-shaped gas flow channel, a temperature-gradient cooling system. Using the 600cm{sup 2} (25x24cm) electrodes, a 30-cell stack (5kW) were constructed and tested.

  13. Debuncher Cooling Limitations to Stacking

    SciTech Connect

    Halling, Mike

    1991-08-13

    During the January studies period we performed studies to determine the effect that debuncher cooling has on the stacking rate. Two different sets of measurements were made separated by about a week. Most measurements reported here are in PBAR log 16, page 243-247. These measurements were made by changing the accelerator timeline to give about 6 seconds between 29's, and then gating the cooling systems to simulate reduced cycle times. For the measurement of the momentum cooling effectiveness the gating switches could not be made to work, so the timeline was changed for each measurement. The cooling power of all three systems was about 800 watts for the tests reported here. We now regularly run at 1200 watts per system.

  14. Transmembrane location of retinal in bacteriorhodopsin by neutron diffraction

    SciTech Connect

    Hauss, T.; Grzesiek, S.; Otto, H.; Westerhausen, J.; Heyn, M.P. )

    1990-05-22

    The transmembrane location of the chromophore of bacteriorhodopsin was obtained by neutron diffraction on oriented stacks of purple membranes. Two selectively deuterated retinals were synthesized and incorporated in bacteriorhodopsin by using the retinal- mutant JW5: retinal-d11 (D11) contained 11 deuterons in the cyclohexene ring, and retinal-d5 (D5) had 5 deuterons as close as possible to the Schiff base end of the chromophore. The membrane stacks had a lamellar spacing of 53.1 A at 86% relative humidity. Five orders were observed in the lamellar diffraction pattern of the D11, D5, and nondeuterated reference samples. The reflections were phased by D2O-H2O exchange. The absolute values of the structure factors were nonlinear functions of the D2O content, suggesting that the coherently scattering domains consisted of asymmetric membrane stacks. The centers of deuteration were determined from the observed intensity differences between labeled and unlabeled samples by using model calculations and Fourier difference methods. With the origin of the coordinate system defined midway between consecutive intermembrane water layers, the coordinates of the center of deuteration of the D11 and D5 label are 10.5 +/- 1.2 and 3.8 +/- 1.5 A, respectively. Alternatively, the label distance may be measured from the nearest membrane surface as defined by the maximum in the neutron scattering length density at the water/membrane interface. With respect to this point, the D11 and D5 labels are located at a depth of 9.9 +/- 1.2 and 16.6 +/- 1.5 A, respectively. The chromophore is tilted with the Schiff base near the middle of the membrane and the ring closer to the membrane surface. The vector connecting the two label positions in the chromophore makes an angle of 40 +/- 12 degrees with the plane of the membrane.

  15. We are in need of sampling the sedimentary cover and bedrock in the Amerasia Basin. (Suggested site locations in the Makarov Basin, the Mendeleev and Lomonosov ridges and adjacent areas.)

    NASA Astrophysics Data System (ADS)

    Lebedeva-Ivanova, N. N.

    2010-12-01

    The Amerasia Basin has a complex origin; alone, the geophysical data can support very different hypotheses. For understanding the tectonic evolution of the Basin and origin of the ridges and troughs it is important to collect geological samples. Based on analyzed seismic data (NP-28 and 26, HOTRAX, Arctic-2000 and TransArctic) over the Makarov Basin, the Mendeleev and Lomonosov ridges and adjacent areas, numbers of key drill sites are proposed. All proposed sites in combinations with other geophysical research of the area are fit well with most of the Site Survey Data Requirements (IODP) for a drilling site. Bedrock samples from key locations are especially needed, with full video or photo documentation of the sampling for avoiding later debates about whether bedrock or ice-drift was collected. Due to close locations to a sea bottom, bedrock can be sampled by gravity piston-cores or shallow drilling. Full stratigraphic sections though the Cenozoic and older sedimentary successions are needed at other proposed key locations for understanding the tectonic evolution of the Amerasia Basin. The depositional environment of the key reflections related to Cenozoic shallow water environments, as recorded in the ACEX drillholes, needs to be investigated in other locations. We will then be able to define better the nature of particular morphological features and construct more reliable tectonic models of the Amerasia Basin, in general.

  16. Fernald radon stack monitor user`s guide

    SciTech Connect

    Whitley, C.R.

    1997-01-01

    The stack monitor uses long-range alpha detection (LRAD) technology for the measurement of radon levels in the stack emissions. The basic principle behind LRAD is the collection of ions created in air through the energy loss mechanisms of decay alphas. This is accomplished by establishing an electric field in the region where alpha decays will occur, and directing the ions via the field onto a biased plate. Accumulation of charge on the plate results in a current in the biasing circuit which can be read with a sensitive electrometer. In electrostatic LRAD designs, the linearity of the measured current with gross alpha activity is well-established. In order to determine radon-222 levels in the presence of other radon isotopes, it is necessary to perform some type of isotopic analysis on the stack samples. In the present case, other radon isotopes of possible concern are radon-219, which occurs in the decay chain of uranium-235, and radon-220, found in the decay chain of thorium-232. Radon-219, with a half-life of four seconds, presents no difficulty for the situation in which emanations from the vitrification process undergo as little as one minute of delay before release into the stack. For example, an initial concentration of 200,000 pCi/l of radon-219 decays to 5 pCi/l in one minute. Radon-220, however, has a half-life of about 55 seconds. If initially present in a substantial ratio to radon-222, a radon gross-alpha measurement on stack emissions would have a significant error if used as a measure for radon-222, even with many minutes of processing delay before the sample was taken.

  17. A bundled-stack discotic columnar liquid crystalline phase with inter-stack electronic coupling

    DOE PAGES

    Wang, Bin; Sun, Runkun; Günbaş, Duygu D.; ...

    2015-06-15

    The first compound proving to be capable of forming a bundled-stack discotic columnar liquid crystalline (BSDCLC) phase was designed and synthesized. Finally, the unique perylene anhydride inter-stack interaction was found to be the key to the formation of the BSDCLC structure and inter-stack electronic coupling (ISEC).

  18. A bundled-stack discotic columnar liquid crystalline phase with inter-stack electronic coupling

    SciTech Connect

    Wang, Bin; Sun, Runkun; Günbaş, Duygu D.; Zhang, Hao; Grozema, Ferdinand C.; Xiao, Kai; Jin, Shi

    2015-06-15

    The first compound proving to be capable of forming a bundled-stack discotic columnar liquid crystalline (BSDCLC) phase was designed and synthesized. Finally, the unique perylene anhydride inter-stack interaction was found to be the key to the formation of the BSDCLC structure and inter-stack electronic coupling (ISEC).

  19. High specific power, direct methanol fuel cell stack

    SciTech Connect

    Ramsey, John C.; Wilson, Mahlon S.

    2007-05-08

    The present invention is a fuel cell stack including at least one direct methanol fuel cell. A cathode manifold is used to convey ambient air to each fuel cell, and an anode manifold is used to convey liquid methanol fuel to each fuel cell. Tie-bolt penetrations and tie-bolts are spaced evenly around the perimeter to hold the fuel cell stack together. Each fuel cell uses two graphite-based plates. One plate includes a cathode active area that is defined by serpentine channels connecting the inlet manifold with an integral flow restrictor to the outlet manifold. The other plate includes an anode active area defined by serpentine channels connecting the inlet and outlet of the anode manifold. Located between the two plates is the fuel cell active region.

  20. Project W-420 stack monitoring system upgrades

    SciTech Connect

    CARPENTER, K.E.

    1999-02-25

    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.

  1. Effective Stack Design in Air Pollution Control.

    ERIC Educational Resources Information Center

    Clarke, John H.

    1968-01-01

    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 high…

  2. Excitation transfer in stacked quantum dot chains

    NASA Astrophysics Data System (ADS)

    Kanjanachuchai, Songphol; Xu, Ming; Jaffré, Alexandre; Jittrong, Apichart; Chokamnuai, Thitipong; Panyakeow, Somsak; Boutchich, Mohamed

    2015-05-01

    Stacked InAs quantum dot chains (QDCs) on InGaAs/GaAs cross-hatch pattern (CHP) templates yield a rich emission spectrum with an unusual carrier transfer characteristic compared to conventional quantum dot (QD) stacks. The photoluminescent spectra of the controlled, single QDC layer comprise multiple peaks from the orthogonal QDCs, the free-standing QDs, the CHP, the wetting layers and the GaAs substrate. When the QDC layers are stacked, employing a 10 nm GaAs spacer between adjacent QDC layers, the PL spectra are dominated by the top-most stack, indicating that the QDC layers are nominally uncoupled. Under high excitation power densities when the high-energy peaks of the top stack are saturated, however, low-energy PL peaks from the bottom stacks emerge as a result of carrier transfers across the GaAs spacers. These unique PL signatures contrast with the state-filling effects in conventional, coupled QD stacks and serve as a means to quickly assess the presence of electronic coupling in stacks of dissimilar-sized nanostructures.

  3. Effective Stack Design in Air Pollution Control.

    ERIC Educational Resources Information Center

    Clarke, John H.

    1968-01-01

    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 high…

  4. Interconnections For Stacked Parallel Computer Modules

    NASA Technical Reports Server (NTRS)

    Johannesson, Richard T.

    1996-01-01

    Concept for interconnecting modules in parallel computers leads to cheaper, smaller, lighter, lower-power computing systems for aerospace, industrial, business, and consumer applications. Computer modules stacked and interconnected in various configurations. Connections among stacks controlled by switching within gateways and/or by addresses on buses.

  5. Locating hybrid individuals in the red wolf (Canis rufus) experimental population area using a spatially targeted sampling strategy and faecal DNA genotyping.

    PubMed

    Adams, Jennifer R; Lucash, Chris; Schutte, Leslie; Waits, Lisette P

    2007-05-01

    Hybridization with coyotes (Canis latrans) continues to threaten the recovery of endangered red wolves (Canis rufus) in North Carolina and requires the development of new strategies to detect and remove coyotes and hybrids. Here, we combine a spatially targeted faecal collection strategy with a previously published reference genotype data filtering method and a genetic test for coyote ancestry to screen portions of the red wolf experimental population area for the presence of nonred wolf canids. We also test the accuracy of our maximum-likelihood assignment test for identifying hybrid individuals using eight microsatellite loci instead of the original 18 loci and compare its performance to the Bayesian approach implemented in newhybrids. We obtained faecal DNA genotypes for 89 samples, 73 of which were matched to 23 known individuals. The performance of two sampling strategies - comprehensive sweep and opportunistic spot-check was evaluated. The opportunistic spot-check sampling strategy required less effort than the comprehensive sweep sampling strategy but identified fewer individuals. Six hybrids or coyotes were detected and five of these individuals were subsequently captured and removed from the population. The accuracy and power of the genetic test for coyote ancestry is decreased when using eight loci; however, nonred wolf canids are identified with high frequency. This combination of molecular and traditional field-based approaches has great potential for addressing the challenge of hybridization in other species and ecosystems.

  6. Classification of cultivation locations of panax quinquefolius L samples using high performance liquid chromatography-electrospray ionization mass spectrometry and chemometric analysis

    USDA-ARS?s Scientific Manuscript database

    Panax quinquefolius L (P. quinquefolius L) samples grown in the United States and China were analyzed with high performance liquid chromatography-mass spectrometry (HPLC—MS). Prior to classification, the two-way datasets were subjected to pretreatment including baseline correction and retention ti...

  7. Classification of cultivation locations of Panax quinquefolius L samples using high performance liquid chromatography-electrospray ionization mass spectrometry and chemometric analysis

    USDA-ARS?s Scientific Manuscript database

    Panax quinquefolius L (P. quinquefolius L) samples grown in the United States and China were analyzed with high performance liquid chromatography-mass spectrometry (HPLC—MS). Prior to classification, the two-way datasets were subjected to pretreatment including baseline correction and retention tim...

  8. Heating Isotopically Labeled Bernal Stacked Graphene: A Raman Spectroscopy Study.

    PubMed

    Ek-Weis, Johan; Costa, Sara; Frank, Otakar; Kalbac, Martin

    2014-02-06

    One of the greatest issues of nanoelectronics today is how to control the heating of the components. Graphene is a promising material in this area, and it is essential to study its thermal properties. Here, the effect of heating a bilayer structure was investigated using in situ Raman spectroscopy. In order to observe the effects on each individual layer, an isotopically labeled bilayer graphene was synthesized where the two layers were composed of different carbon isotopes. Therefore, the frequency of the phonons in the Raman spectra was shifted in relation to each other. This technique was used to investigate the influence of different stacking order. It was found that in bilayer graphene grown by chemical vapor deposition (CVD), the two layers behave very similarly for both Bernal stacking and randomly oriented structures, while for transferred samples, the layers act more independently. This highlights a significant dependence on the sample preparation procedure.

  9. Compact piezoelectric stacked actuators for high power applications.

    PubMed

    Yao, K; Uchino, K; Xu, Y; Dong, S; Lim, L C

    2000-01-01

    Small, hollow, multilayer actuators with a diameter of 3 mm were fabricated by the stacking method from piezoelectric hard lead zirconate titanate (PZT) ceramics. Langevin vibrators were also constructed with the hollow multilayer actuators. The performance capabilities of the actuator and Langevin vibrator samples were examined under high-power conditions. The high-power vibration level at a given sinusoidal drive voltage was significantly enhanced by using a multilayer structure under either a nonresonance or resonance condition. A maximum vibration velocity of 0.17 m/sec was obtained for the 9-layer actuator sample under nonresonance conditions. The vibration velocity was further improved with the Langevin vibrator driven at the resonance frequency. The temperature rise due to heat generation under high-power conditions was the immediate limitation on the maximum accessible vibration velocity for the stacked actuators.

  10. Discrete stacking of aromatic oligoamide macrocycles.

    PubMed

    Wu, Xiangxiang; Liu, Rui; Sathyamoorthy, Bharathwaj; Yamato, Kazuhiro; Liang, Guoxing; Shen, Lin; Ma, Sufang; Sukumaran, Dinesh K; Szyperski, Thomas; Fang, Weihai; He, Lan; Chen, Xuebo; Gong, Bing

    2015-05-13

    Unlike the precise structural control typical of closed assemblies, curbing the stacking of disc- and ring-shaped molecules is quite challenging. Here we report the discrete stacking of rigid aromatic oligoamide macrocycles 1. With increasing concentration, the aggregation of 1 quickly plateaus, forming a discrete oligomer, as suggested by 1D (1)H, 2D nuclear Overhauser effect, and diffusion-ordered NMR spectroscopy. Quantum-chemical calculations indicate that the tetramer of 1 is the most stable among oligomeric stacks. X-ray crystallography revealed a tetrameric stack containing identical molecules adopting two different conformations. With a defined length and an inner pore capable of accommodating distinctly different guests, the tetramers of 1 densely pack into 2D layers. Besides being a rare system of conformation-regulated supramolecular oligomerization, the discrete stacks of 1, along with their higher-order assemblies, may offer new nanotechnological applications.

  11. Status of MCFC stack technology at IHI

    SciTech Connect

    Hosaka, M.; Morita, T.; Matsuyama, T.; Otsubo, M.

    1996-12-31

    The molten carbonate fuel cell (MCFC) is a promising option for highly efficient power generation possible to enlarge. IHI has been studying parallel flow MCFC stacks with internal manifolds that have a large electrode area of 1m{sup 2}. IHI will make two 250 kW stacks for MW plant, and has begun to make cell components for the plant. To improve the stability of stack, soft corrugated plate used in the separator has been developed, and a way of gathering current from stacks has been studied. The DC output potential of the plant being very high, the design of electric insulation will be very important. A 20 kW short stack test was conducted in 1995 FY to certificate some of the improvements and components of the MW plant. These activities are presented below.

  12. Stacking textures and singularities in bilayer graphene

    NASA Astrophysics Data System (ADS)

    Mele, Eugene

    2014-03-01

    Multilayer graphenes feature special functionalities that microscopically arise from the atomic registry when graphene sheets are stacked. These depend on relative lateral translations, rotations and layer symmetry breaking that can occur spontaneously or be induced. This talk will focus on bilayer graphenes (BLG) in which the stacking arrangement varies in space. We examine domain walls where the local stacking order switches from local AB to BA registry, and study the electronic modes at the boundary by analyzing their valley-projected four band continuum models augmented by numerical calculations on a lattice. We then consider the more general family of two dimensional strain-minimizing BLG stacking textures, finding that they are twisted textures of the interlayer displacement field. We study the interactions and composition rules for these elementary textures which permit a unified treatment of stacking point defects, domain walls and twisted graphenes. Collaborators: Z. Addison, X. Gong, A.H. MacDonald and Fan Zhang

  13. Rapid and Nondestructive Identification of Polytypism and Stacking Sequences in Few-Layer Molybdenum Diselenide by Raman Spectroscopy

    DOE PAGES

    Lu, Xin; Utama, M. Iqbal Bakti; Lin, Junhao; ...

    2015-07-02

    Various combinations of interlayer shear modes emerge in few-layer molybdenum diselenide grown by chemical vapor deposition depending on the stacking configuration of the sample. Raman measurements may also reveal polytypism and stacking faults, as supported by first principles calculations and high-resolution transmission electron microscopy. Thus, Raman spectroscopy is an important tool in probing stacking-dependent properties in few-layer 2D materials.

  14. Dynamic behaviour of SOFC short stacks

    NASA Astrophysics Data System (ADS)

    Molinelli, Michele; Larrain, Diego; Autissier, Nordahl; Ihringer, Raphaël; Sfeir, Joseph; Badel, Nicolas; Bucheli, Olivier; Van herle, Jan

    Electrical output behaviour obtained on solid oxide fuel cell stacks, based on planar anode supported cells (50 or 100 cm 2 active area) and metallic interconnects, is reported. Stacks (1-12 cells) have been operated with cathode air and anode hydrogen flows between 750 and 800 °C operating temperature. At first polarisation, an activation phase (increase in power density) is typically observed, ascribed to the cathode but not clarified. Activation may extend over days or weeks. The materials are fairly resistant to thermal cycling. A 1-cell stack cycled five times in 4 days at heating/cooling rates of 100-300 K h -1, showed no accelerated degradation. In a 5-cell stack, open circuit voltage (OCV) of all cells remained constant after three full cycles (800-25 °C). Power output is little affected by air flow but markedly influenced by small fuel flow variation. Fuel utilisation reached 88% in one 5-cell stack test. Performance homogeneity between cells lay at ±4-8% for three different 5- or 6-cell stacks, but was poor for a 12-cell stack with respect to the border cells. Degradation of a 1-cell stack operated for 5500 h showed clear dependence on operating conditions (cell voltage, fuel conversion), believed to be related to anode reoxidation (Ni). A 6-cell stack (50 cm 2 cells) delivering 100 W el at 790 °C (1 kW el L -1 or 0.34 W cm -2) went through a fuel supply interruption and a thermal cycle, with one out of the six cells slightly underperforming after these events. This cell was eventually responsible (hot spot) for stack failure.

  15. Assessment of dioxin-like activity in PM10 air samples from an industrial location in Algeria, using the DRE-CALUX bioassay.

    PubMed

    Khedidji, Sidali; Croes, Kim; Yassaa, Noureddine; Ladji, Riad; Denison, Michael S; Baeyens, Willy; Elskens, Marc

    2017-05-01

    When compared to the European guidelines, PM10 (particulate matter up to 10-μm size) concentrations in Algeria are often exceeding the maximum limits, and in general, no information exists on the compounds bound on its surface. The objective of this study was to measure the dioxin-like activity of polychlorinated dibenzodioxines and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs) in the PM10 fraction at the Sour El Ghozlane cement plant in Algeria. PM10 samples (n = 23) were taken between 24 March and 15 April 2013, using a medium volume sampler and 47-mm PTFE filters. The 24-h samples were dried to determine the PM10 content and afterward extracted, cleaned up, and analyzed with the dioxin-responsive element-chemical-activated luciferase gene expression (DRE-CALUX) bioassay. Our results showed that the measured bioanalytical equivalents (BEQs) were similar to those in other international industrial sites worldwide. The PCDD/Fs and dioxin-like PCBs (dl-PCBs) were positively correlated (rho = 0.6, p = 0.002), indicating that they have similar sources. Furthermore, samples from March showed higher PCDD/F and dl-PCB BEQs and humidity but lower temperatures compared to samples from April, while there was no difference in the PM10 concentrations between the two months. These results reveal that PM10 alone is not a good proxy and that meteorological conditions are an important factor in assessing dioxin-like pollution in the atmosphere. It seems that, at present, there is no health hazard through direct airborne human exposure to dioxin-like pollutants in PM10 from this site. However, it is important to monitor these POPs for a longer period of time and also to gain more insight in their distribution between the particulate and gas phase in relation to meteorological conditions.

  16. Probing Temperature Inside Planar SOFC Short Stack, Modules, and Stack Series

    NASA Astrophysics Data System (ADS)

    Yu, Rong; Guan, Wanbing; Zhou, Xiao-Dong

    2017-02-01

    Probing temperature inside a solid oxide fuel cell (SOFC) stack lies at the heart of the development of high-performance and stable SOFC systems. In this article, we report our recent work on the direct measurements of the temperature in three types of SOFC systems: a 5-cell short stack, a 30-cell stack module, and a stack series consisting of two 30-cell stack modules. The dependence of temperature on the gas flow rate and current density was studied under a current sweep or steady-state operation. During the current sweep, the temperature inside the 5-cell stack decreased with increasing current, while it increased significantly at the bottom and top of the 30-cell stack. During a steady-state operation, the temperature of the 5-cell stack was stable while it was increased in the 30-cell stack. In the stack series, the maximum temperature gradient reached 190°C when the gas was not preheated. If the gas was preheated and the temperature gradient was reduced to 23°C in the stack series with the presence of a preheating gas and segmented temperature control, this resulted in a low degradation rate.

  17. Electronic structure of stacking faults in rhombohedral graphite

    NASA Astrophysics Data System (ADS)

    Taut, M.; Koepernik, K.; Richter, M.

    2014-08-01

    The electronic structure of stacking faults and surfaces without and with an additional displaced layer is calculated for the case of rhombohedral (ABC) graphite. The full-potential local-orbital code and the generalized gradient approximation to density functional theory are used. All considered surfaces and interfaces induce surface/interface bands. All discovered surface and interface bands are restricted to the vicinity of the symmetry line K-M in the two-dimensional Brillouin zone. There are groups of localized band pairs around ±0, ±0.2, and ±0.6 eV for one of the two considered types of stacking faults; ±0 and ±0.5 eV for the other type and for a displaced surface layer. At the K point in the Brillouin zone, there is a one-to-one correspondence between these localized bands and the eigenvalues of those linear atomic clusters, which are produced by the perturbation of periodicity due to the displaced surface layer or due to the stacking faults. Some of the localized bands produce strong van Hove singularities in the local density of states near the surface or interface at energies up to several 0.1 eV. It is suggested to check these findings experimentally by appropriate spectroscopic methods. Undisturbed bulk (ABC) graphite is virtually a zero-gap semiconductor with a minute density of states at the Fermi energy. Both the surface and any of the considered stacking faults produce sharp peaks in the local density of states near the perturbation at energies of about 10 meV around the Fermi energy. This should provide a considerable contribution to the conductivity and its temperature dependence for samples with stacking faults or large surface-to-volume fraction.

  18. Location and age of foraminifer samples examined by Chevron Petroleum Company paleontologists from more than 2,500 oil test wells in California

    USGS Publications Warehouse

    Brabb, Earl E.

    2011-01-01

    Chevron Petroleum Company in 2001 donated an estimated 50,000 foraminifer slides, 5,000 well logs, geologic and surface locality maps, and paleontologic reports to the California Academy of Sciences and Stanford University for safekeeping, because they stopped or cut back exploration for petroleum deposits in California. The material was loaned to Earl Brabb temporarily so that information useful to the U.S. Geological Survey could be extracted. Among the estimated 5,000 well logs, more than 2,500 were printed on fragile Ozalid paper that had deteriorated by turning brown and hardening so that they could be easily damaged. These 2,516 well logs were scanned to provide a digital copy of the information. The 2,516 wells extend over an area from Eureka in Humboldt County south to the Imperial Valley and from the Pacific Ocean east to the eastern side of the Great Valley and the Los Angeles Basin. The wells are located in 410 7.5-minute quadrangle maps in 42 counties. The digital information herein preserves the data, makes the logs easily distributed to others interested in subsurface geology, and makes previously proprietary information widely available to the public for the first time.

  19. Control of layer stacking in CVD graphene under quasi-static condition.

    PubMed

    Subhedar, Kiran M; Sharma, Indu; Dhakate, Sanjay R

    2015-09-14

    The type of layer stacking in bilayer graphene has a significant influence on its electronic properties because of the contrast nature of layer coupling. Herein, different geometries of the reaction site for the growth of bilayer graphene by the chemical vapor deposition (CVD) technique and their effects on the nature of layer stacking are investigated. Micro-Raman mapping and curve fitting analysis confirmed the type of layer stacking for the CVD grown bilayer graphene. The samples grown with sandwiched structure such as quartz/Cu foil/quartz along with a spacer, between the two quartz plates to create a sealed space, resulted in Bernal or AB stacked bilayer graphene while the sample sandwiched without a spacer produced the twisted bilayer graphene. The contrast difference in the layer stacking is a consequence of the difference in the growth mechanism associated with different geometries of the reaction site. The diffusion dominated process under quasi-static control is responsible for the growth of twisted bilayer graphene in sandwiched geometry while surface controlled growth with ample and continual supply of carbon in sandwiched geometry along with a spacer, leads to AB stacked bilayer graphene. Through this new approach, an efficient technique is presented to control the nature of layer stacking.

  20. 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

  1. Temperature dependent photoluminescence and micromapping of multiple stacks InAs quantum dots

    SciTech Connect

    Xu, Ming Jaffré, Alexandre Alvarez, José Kleider, Jean-Paul Boutchich, Mohamed; Jittrong, Apichat; Chokamnuai, Thitipong; Panyakeow, Somsak; Kanjanachuchai, Songphol

    2015-02-27

    We utilized temperature dependent photoluminescence (PL) techniques to investigate 1, 3 and 5 stack InGaAs quantum dots (QDs) grown on cross-hatch patterns. PL mapping can well reproduce the QDs distribution as AFM and position dependency of QD growth. It is possible to observe crystallographic dependent PL. The temperature dependent spectra exhibit the QDs energy distribution which reflects the size and shape. The inter-dot carrier coupling effect is observed and translated as a red shift of 120mV on the [1–10] direction peak is observed at 30K on 1 stack with regards to 3 stacks samples, which is assigned to lateral coupling.

  2. Pi-stacked interactions in explosive crystals: buffers against external mechanical stimuli.

    PubMed

    Zhang, Chaoyang; Wang, Xiaochuan; Huang, Hui

    2008-07-02

    The pi-stacked interactions in some explosive crystal packing are discussed. Taking a typical pi-stacked explosive 2,4,6-trinitrobenzene-1,3,5-triamine (TATB) as a sample and using molecular simulations, we investigated the nature of the pi-stacked interactions versus the external mechanical stimuli causing possible slide and compression of explosives. As a result, between the neighbor layers in the TATB unit cell, the electrostatic attraction decreases with a little decrease of vdW attraction when its top layer slides, whereas the vdW attraction increases with a decrease of electrostatic attraction when TATB crystal is compressed along its c axis. Meanwhile, we studied the correlation between the pi-stacked structures and the impact sensitivities of explosives by means of three representatives including TATB with typical planar pi-stacked structures, 2,2-dinitroethylene-1,1-diamine (Fox-7) with wavelike pi-stacked structures, and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) without pi-stacked structure. The results showed that pi-stacked structures, particularly planar layers, can effectively buffer against external mechanical stimuli. That is, pi-stacked structures can partly convert the mechanical energy acting on them into their intermolecular interaction energy, to avoid the increase of the molecular vibration resulting in the explosive decomposition, the formation of hot spots, and the final detonation. This is another reason for the low mechanical sensitivity of pi-stacked explosives besides their stable conjugated molecular structures.

  3. Stacking Interactions between 9-Methyladenine and Heterocycles Commonly Found in Pharmaceuticals.

    PubMed

    An, Yi; Doney, Analise C; Andrade, Rodrigo B; Wheeler, Steven E

    2016-05-23

    Complexes of 9-methyladenine with 46 heterocycles commonly found in drugs were located using dispersion-corrected density functional theory, providing a representative set of 408 unique stacked dimers. The predicted binding enthalpies for each heterocycle span a broad range, highlighting the strong dependence of heterocycle stacking interactions on the relative orientation of the interacting rings. Overall, the presence of NH and carbonyl groups lead to the strongest stacking interactions with 9-methyadenine, and the strength of π-stacking interactions is sensitive to the distribution of heteroatoms within the ring as well as the specific tautomer considered. Although molecular dipole moments provide a sound predictor of the strengths and orientations of the 28 monocyclic heterocycles considered, dipole moments for the larger fused heterocycles show very little correlation with the predicted binding enthalpies.

  4. Limestone/adipic acid FGD and stack opacity reduction pilot plant tests at Big Rivers

    SciTech Connect

    Laslo, D.; Bakke, E.; Chisholm, E.

    1984-01-01

    Big Rivers Electric Corporation (BREC) contracted Peabody Process Systems, Inc. (PPSI) to install a flue gas cleaning (FGC) pilot plant at the BREC R.D. Green Station Unit No. 2 located at Sebree, KY. A six month test program was completed demonstrating technology for: alternatives to using lime as an alkali; methods for improving cake dewatering; identification of the causes of high stack opacity; and methods for the reduction of high stack opacity. This paper presents highlights extracted from the reports submitted by PPSI to BREC on this test program. BREC was primarily interested in reduction of operating costs, if possible, by using an alkali less expensive than lime, and by improving the poor dewatering characteristic inherent in a dolomitic lime system. BREC was also within compliance for particulate emissions and opacity in the duct after the dry electrostatic precipitator, but not in compliance with the stack opacity regulation, and therefore wanted to investigate methods for stack opacity reduction.

  5. Dynamical stability of slip-stacking particles

    SciTech Connect

    Eldred, Jeffrey; Zwaska, Robert

    2014-09-01

    We study the stability of particles in slip-stacking configuration, used to nearly double proton beam intensity at Fermilab. We introduce universal area factors to calculate the available phase space area for any set of beam parameters without individual simulation. We find perturbative solutions for stable particle trajectories. We establish Booster beam quality requirements to achieve 97% slip-stacking efficiency. We show that slip-stacking dynamics directly correspond to the driven pendulum and to the system of two standing-wave traps moving with respect to each other.

  6. Passive stacks in a multifamily housing project

    SciTech Connect

    Saum, D.

    1995-12-31

    The Summerfield multi-family, 1242 unit housing project that has been under construction since 1993 in Prince Georges County Maryland near Washington, DC suggests that passive stacks provides significant radon mitigation in multi-family construction. Random radon tests in these buildings indicate an average indoor ground floor concentration of 0.3 pCi/L with the stacks open, and 1.3 pCi/L with the stacks sealed. These buildings were built with post-tension slabs which should be more airtight than conventional floating slabs, and measurements show that the pressure field extension in these slabs in very good.

  7. Repetitively pulsed high power stacked Blumlein generators

    NASA Astrophysics Data System (ADS)

    Davanloo, F.; Borovina, D. L.; Collins, C. B.; Agee, F. J.; Kingsley, L. E.

    1995-05-01

    The stacked Blumlein pulse generators developed at the University of Texas at Dallas consist of several triaxial Blumleins stacked in series at one end. The lines are charged in parallel and synchronously commuted with a single switching element at the other end. In this way, relatively low charging voltages are multiplied to give the desired discharge voltage across an arbitrary load. Described here is the progress in development and characterization of these novel pulse-power generators capable of discharging at high repetition rates. The introduction of a tapered transmission line concept to the stacked Blumlein design provided fine tuning of output waveforms.

  8. Molten carbonate fuel cell stack design options

    NASA Astrophysics Data System (ADS)

    Benjamin, T. G.; Petri, R. J.

    Significant strides in molten carbonate fuel cell (MCFC) life and performance were made duing the last 20 years. Results include single cell performance improvement from 10 watts/sq ft to 120 watts/sq ft, testing of several subscale stacks, and significant reductions in cost. In the 1980s, attention has turned toward stack related issues including component dimensional and structural stability, cathode dissolution, sulfur poisoning, hardware design, electrolyte management, carbon dioxide conservation, internal reforming, and systems considerations. The MCFC stack hardware design options are discussed and a brief introduction to MCFC technology is presented.

  9. Image Stacking Method Application for Low Earth Orbit Faint Objects

    NASA Astrophysics Data System (ADS)

    Tagawa, M.; Matsumoto, H.; Yanagisawa, T.; Kurosaki, H.; Oda, H.; Kitazawa, Y.; Hanada, T.

    2013-09-01

    telescopes conduct chasing observation for the estimated apparent trajectory and stack the images based on the relative apparent motion search for true object. Therefore accuracy evaluation for initial orbit estimation result means to verify that apparent motions of true object are able to being searched. The current image stacking method applied for geostationary orbit based on assumptions that apparent motion can be treated as straight lines. Thus the linearity and uniformity assessment of the apparent motion in ground-based tracking observation using initial orbit estimation result is required. This paper introduces the apparent motion prediction result with reasonably assumed orbit estimation errors. The ground observatories are assumed to be located around the polar regions. Then this paper discusses image stacking feasibility for the apparent motion based on space-based orbit estimation result.

  10. Stacked vapor fed amtec modules

    DOEpatents

    Sievers, Robert K.

    1989-01-01

    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.

  11. Effects of stacking disorder on thermal conductivity of cubic ice

    NASA Astrophysics Data System (ADS)

    Johari, G. P.; Andersson, Ove

    2015-08-01

    Cubic ice is said to have stacking disorder when the H2O sequences in its structure (space group F d 3 ¯ m ) are interlaced with hexagonal ice (space group P63/mmc) sequences, known as stacking faults. Diffraction methods have shown that the extent of this disorder varies in samples made by different methods, thermal history, and the temperature T, but other physical properties of cubic and hexagonal ices barely differ. We had found that at 160 K, the thermal conductivity, κ, of cubic ice is ˜20% less than that of hexagonal ice, and this difference varies for cubic ice samples prepared by different methods and/or subjected to different thermal history. After reviewing the methods of forming cubic ice, we report an investigation of the effects of stacking disorder and other features by using new data, and by analyzing our previous data on the dependence of κ on T and on the pressure. We conclude that the lower κ of cubic ice and its weaker T-dependence is due mainly to stacking disorder and small crystal sizes. On in situ heating at 20-50 MPa pressure, κ increases and cubic ice irreversibly transforms more sharply to ice Ih, and at a higher T of ˜220 K, than it does in ex situ studies. Cooling and heating between 115 and 130 K at 0.1 K min-1 rate yield the same κ value, indicating that the state of cubic ice in these conditions does not change with time and T. The increase in κ of cubic ice observed on heat-annealing before its conversion to hexagonal ice is attributed to the loss of stacking faults and other types of disorders, and to grain growth. After discussing the consequences of our findings on other properties, we suggest that detailed studies of variation of a given property of cubic ice with the fraction of stacking faults in its structure may reveal more about the effect of this disorder. A similar disorder may occur in the mono-layers of H2O adsorbed on a substrate, in bulk materials comprised of two dimensional layers, in diamond and in

  12. Effects of stacking disorder on thermal conductivity of cubic ice.

    PubMed

    Johari, G P; Andersson, Ove

    2015-08-07

    Cubic ice is said to have stacking disorder when the H2O sequences in its structure (space group Fd3̄m) are interlaced with hexagonal ice (space group P6(3)/mmc) sequences, known as stacking faults. Diffraction methods have shown that the extent of this disorder varies in samples made by different methods, thermal history, and the temperature T, but other physical properties of cubic and hexagonal ices barely differ. We had found that at 160 K, the thermal conductivity, κ, of cubic ice is ∼20% less than that of hexagonal ice, and this difference varies for cubic ice samples prepared by different methods and/or subjected to different thermal history. After reviewing the methods of forming cubic ice, we report an investigation of the effects of stacking disorder and other features by using new data, and by analyzing our previous data on the dependence of κ on T and on the pressure. We conclude that the lower κ of cubic ice and its weaker T-dependence is due mainly to stacking disorder and small crystal sizes. On in situ heating at 20-50 MPa pressure, κ increases and cubic ice irreversibly transforms more sharply to ice Ih, and at a higher T of ∼220 K, than it does in ex situ studies. Cooling and heating between 115 and 130 K at 0.1 K min(-1) rate yield the same κ value, indicating that the state of cubic ice in these conditions does not change with time and T. The increase in κ of cubic ice observed on heat-annealing before its conversion to hexagonal ice is attributed to the loss of stacking faults and other types of disorders, and to grain growth. After discussing the consequences of our findings on other properties, we suggest that detailed studies of variation of a given property of cubic ice with the fraction of stacking faults in its structure may reveal more about the effect of this disorder. A similar disorder may occur in the mono-layers of H2O adsorbed on a substrate, in bulk materials comprised of two dimensional layers, in diamond and in

  13. The effects of location, experiences with the civil disturbances and religion on death anxiety and manifest anxiety in a sample of Northern Ireland university students.

    PubMed

    Mercer, G W; Bunting, B; Snook, S

    1979-06-01

    A total of 315 Northern Ireland university students were compared to 302 Republic of Ireland university students in terms of death anxiety, manifest anxiety, and perception of dangerousness of aspects of their environment and attitudes toward the civil disturbances in Northern Ireland. Also using these variables in the Northern Ireland sample, Protestants were compared to Catholics, those having had experiences with the disturbances were compared to those not having had such experiences, and those living in nominally dangerous areas of Belfast were compared to those living in nominally safer areas of Belfast. Students living in Northern Ireland had higher death anxiety and stronger fears than students living in the Republic. Those having had experiences with the civil violence had higher manifest anxiety and stronger fears than those not having has such experiences. Persons living in safe environments thought the disturbances to be more serious than those living in more dangerous environments, a result which is discussed in terms of the media and cognitive dissonance. Finally, an argument is made that the influence of religious denomination is an overemphasized variable in the understanding of the civil disturbances.

  14. Wearable solar cells by stacking textile electrodes.

    PubMed

    Pan, Shaowu; Yang, Zhibin; Chen, Peining; Deng, Jue; Li, Houpu; Peng, Huisheng

    2014-06-10

    A new and general method to produce flexible, wearable dye-sensitized solar cell (DSC) textiles by the stacking of two textile electrodes has been developed. A metal-textile electrode that was made from micrometer-sized metal wires was used as a working electrode, while the textile counter electrode was woven from highly aligned carbon nanotube fibers with high mechanical strengths and electrical conductivities. The resulting DSC textile exhibited a high energy conversion efficiency that was well maintained under bending. Compared with the woven DSC textiles that are based on wire-shaped devices, this stacked DSC textile unexpectedly exhibited a unique deformation from a rectangle to a parallelogram, which is highly desired in portable electronics. This lightweight and wearable stacked DSC textile is superior to conventional planar DSCs because the energy conversion efficiency of the stacked DSC textile was independent of the angle of incident light.

  15. Near-Earth Asteroid Stack - Mission Animation

    NASA Image and Video Library

    A possible stack configuration - a deep space habitat, the Orion Multi-Purpose Crew Vehicle and Space Exploration Vehicle - approaches a near-Earth asteroid. During a mission that could take months...

  16. Characterization of Piezoelectric Stacks for Space Applications

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Jones, Christopher; Aldrich, Jack; Blodget, Chad; Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph

    2008-01-01

    Future NASA missions are increasingly seeking to actuate mechanisms to precision levels in the nanometer range and below. Co-fired multilayer piezoelectric stacks offer the required actuation precision that is needed for such mechanisms. To obtain performance statistics and determine reliability for extended use, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and high temperatures and voltages. In order to study the lifetime performance of these stacks, five actuators were driven sinusoidally for up to ten billion cycles. An automated data acquisition system was developed and implemented to monitor each stack's electrical current and voltage waveforms over the life of the test. As part of the monitoring tests, the displacement, impedance, capacitance and leakage current were measured to assess the operation degradation. This paper presents some of the results of this effort.

  17. Stacked RADFETs for increased radiation sensitivity

    SciTech Connect

    O`Connell, B.; Kelleher, A.; Lane, W.; Adams, L.

    1996-06-01

    Hitherto, pMOS Radiation Sensitive Field Effect Transistors (RADFETs) have not been able to detect doses in the milli-rad range, which are required for low dose clinical/personnel applications. This paper reports on further investigation of a design approach, where RADFETs are connected in a stacked sequence so that increased radiation sensitivity is obtained. The radiation sensitivity obtained for 40 stacked RADFETs is approximately 220 times the single RADFET sensitivity. This enables radiation sensitivities in the milli-rad range to be measured. Theoretical equations governing the threshold voltage of a MOS device as a function of bulk-source voltage are used to theoretically evaluate the output voltage of the stacked structure. Measurement and theory are found to agree closely in this analysis. Percent drift and % fading of the single RADFET, as a function of total radiation induced shift in V{sub T}, is similar to that of the stacked structure.

  18. Stacking fault energy in some single crystals

    NASA Astrophysics Data System (ADS)

    Vora, Aditya M.

    2012-06-01

    The stacking fault energy of single crystals has been reported using the peak shift method. Presently studied all single crystals are grown by using a direct vapor transport (DVT) technique in the laboratory. The structural characterizations of these crystals are made by XRD. Considerable variations are shown in deformation (α) and growth (β) probabilities in single crystals due to off-stoichiometry, which possesses the stacking fault in the single crystal.

  19. Stacking interactions in PUF-RNA complexes

    SciTech Connect

    Yiling Koh, Yvonne; Wang, Yeming; Qiu, Chen; Opperman, Laura; Gross, Leah; Tanaka Hall, Traci M; Wickens, Marvin

    2012-07-02

    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.

  20. PieceStack: Toward Better Understanding of.

    PubMed

    Wu, Tongshuang; Wu, Yingcai; Shi, Conglei; Qu, Huamin; Cui, Weiwei

    2016-02-24

    Stacked graphs have been widely adopted in various fields, because they are capable of hierarchically visualizing a set of temporal sequences as well as their aggregation. However, because of visual illusion issues, connections between overly-detailed individual layers and overly-generalized aggregation are intercepted. Consequently, information in this area has yet to be fully excavated. Thus, we present PieceStack in this paper, to reveal the relevance of stacked graphs in understanding intrinsic details of their displayed shapes. This new visual analytic design interprets the ways through which aggregations are generated with individual layers by interactively splitting and re-constructing the stacked graphs. A clustering algorithm is designed to partition stacked graphs into sub-aggregated pieces based on trend similarities of layers. We then visualize the pieces with augmented encoding to help analysts decompose and explore the graphs with respect to their interests. Case studies and a user study are conducted to demonstrate the usefulness of our technique in understanding the formation of stacked graphs.

  1. Stacking-dependent interlayer coupling in trilayer MoS2 with broken inversion symmetry

    DOE PAGES

    Yan, Jiaxu; Wang, Xingli; Tay, Beng Kang; ...

    2015-11-13

    The stacking configuration in few-layer two-dimensional (2D) materials results in different structural symmetries and layer-to-layer interactions, and hence it provides a very useful parameter for tuning their electronic properties. For example, ABA-stacking trilayer graphene remains semimetallic similar to that of monolayer, while ABC-stacking is predicted to be a tunable band gap semiconductor under an external electric field. Such stacking dependence resulting from many-body interactions has recently been the focus of intense research activities. Here we demonstrate that few-layer MoS2 samples grown by chemical vapor deposition with different stacking configurations (AA, AB for bilayer; AAB, ABB, ABA, AAA for trilayer) exhibitmore » distinct coupling phenomena in both photoluminescence and Raman spectra. By means of ultralow-frequency (ULF) Raman spectroscopy, we demonstrate that the evolution of interlayer interaction with various stacking configurations correlates strongly with layer-breathing mode (LBM) vibrations. Our ab initio calculations reveal that the layer-dependent properties arise from both the spin–orbit coupling (SOC) and interlayer coupling in different structural symmetries. Lastly, such detailed understanding provides useful guidance for future spintronics fabrication using various stacked few-layer MoS2 blocks.« less

  2. Free energy analysis and mechanism of base pair stacking in nicked DNA

    PubMed Central

    Häse, Florian; Zacharias, Martin

    2016-01-01

    The equilibrium of stacked and unstacked base pairs is of central importance for all nucleic acid structure formation processes. The stacking equilibrium is influenced by intramolecular interactions between nucleosides but also by interactions with the solvent. Realistic simulations on nucleic acid structure formation and flexibility require an accurate description of the stacking geometry and stability and its sequence dependence. Free energy simulations have been conducted on a series of double stranded DNA molecules with a central strand break (nick) in one strand. The change in free energy upon unstacking was calculated for all ten possible base pair steps using umbrella sampling along a center-of-mass separation coordinate and including a comparison of different water models. Comparison to experimental studies indicates qualitative agreement of the stability order but a general overestimation of base pair stacking interactions in the simulations. A significant dependence of calculated nucleobase stacking free energies on the employed water model was observed with the tendency of stacking free energies being more accurately reproduced by more complex water models. The simulation studies also suggest a mechanism of stacking/unstacking that involves significant motions perpendicular to the reaction coordinate and indicate that the equilibrium nicked base pair step may slightly differ from regular B-DNA geometry in a sequence-dependent manner. PMID:27407106

  3. Free energy analysis and mechanism of base pair stacking in nicked DNA.

    PubMed

    Häse, Florian; Zacharias, Martin

    2016-09-06

    The equilibrium of stacked and unstacked base pairs is of central importance for all nucleic acid structure formation processes. The stacking equilibrium is influenced by intramolecular interactions between nucleosides but also by interactions with the solvent. Realistic simulations on nucleic acid structure formation and flexibility require an accurate description of the stacking geometry and stability and its sequence dependence. Free energy simulations have been conducted on a series of double stranded DNA molecules with a central strand break (nick) in one strand. The change in free energy upon unstacking was calculated for all ten possible base pair steps using umbrella sampling along a center-of-mass separation coordinate and including a comparison of different water models. Comparison to experimental studies indicates qualitative agreement of the stability order but a general overestimation of base pair stacking interactions in the simulations. A significant dependence of calculated nucleobase stacking free energies on the employed water model was observed with the tendency of stacking free energies being more accurately reproduced by more complex water models. The simulation studies also suggest a mechanism of stacking/unstacking that involves significant motions perpendicular to the reaction coordinate and indicate that the equilibrium nicked base pair step may slightly differ from regular B-DNA geometry in a sequence-dependent manner. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  4. Automated and Accurate Detection of Soma Location and Surface Morphology in Large-Scale 3D Neuron Images

    PubMed Central

    Yan, Cheng; Li, Anan; Zhang, Bin; Ding, Wenxiang; Luo, Qingming; Gong, Hui

    2013-01-01

    Automated and accurate localization and morphometry of somas in 3D neuron images is essential for quantitative studies of neural networks in the brain. However, previous methods are limited in obtaining the location and surface morphology of somas with variable size and uneven staining in large-scale 3D neuron images. In this work, we proposed a method for automated soma locating in large-scale 3D neuron images that contain relatively sparse soma distributions. This method involves three steps: (i) deblocking the image with overlap between adjacent sub-stacks; (ii) locating the somas in each small sub-stack using multi-scale morphological close and adaptive thresholds; and (iii) fusion of the repeatedly located somas in all sub-stacks. We also describe a new method for the accurate detection of the surface morphology of somas containing hollowness; this was achieved by improving the classical Rayburst Sampling with a new gradient-based criteria. Three 3D neuron image stacks of different sizes were used to quantitatively validate our methods. For the soma localization algorithm, the average recall and precision were greater than 93% and 96%, respectively. For the soma surface detection algorithm, the overlap of the volumes created by automatic detection of soma surfaces and manually segmenting soma volumes was more than 84% for 89% of all correctly detected somas. Our method for locating somas can reveal the soma distributions in large-scale neural networks more efficiently. The method for soma surface detection will serve as a valuable tool for systematic studies of neuron types based on neuron structure. PMID:23638117

  5. Broadcast of microbial aerosols by stacks of sewage treatment plants and effects of ozonation on bacteria in the gaseous effluent.

    PubMed

    Pereira, M R; Benjaminson, M A

    1975-01-01

    In the aeration basins of sewage treatment plants, compressed air is supplied to diffusers near the bottom of tanks to aid in the conversion by aerobic bacteria of dissolved and suspended solids of sewage into particles that will settle. Air bubbles breaking at the air-water interface will aerosolize bacteria that concentrate in the uppermost microlayer. The microbiological output of a plant in New York City with such a system was monitored. Samples of the gaseous effluent were collected inside the aeration building, inside the building's stack, 300 meters upwind (background sampler), and 300 meters downwind (test sampler), using Andersen samplers. Among the genera identified in the atmosphere in and around the plant were Mycobacterium, Klebsiella, and Streptococcus, all potentially pathogenic. The disinfection power of ozone, which is generally used for odor control, was also tested. Samples were taken from the ozone mixing chamber in the stack of the thickentng tank building. No significant difference in general bacterial counts could be detected at different levels of ozone production. It appears that in the air, ozone is an ineffective bactericidal agent. Results in this preliminary study demonstrate the need to evaluate the hazard of microbial aerosols generated by sewage treatment plants similar to the one studied. The possibility of such hazards is of special interest where facilities are located upwind of populations especially susceptible to infections, because of age of debility. Correlations with epidemiologic data are indicated.

  6. Broadcast of microbial aerosols by stacks of sewage treatment plants and effects of ozonation on bacteria in the gaseous effluent.

    PubMed Central

    Pereira, M R; Benjaminson, M A

    1975-01-01

    In the aeration basins of sewage treatment plants, compressed air is supplied to diffusers near the bottom of tanks to aid in the conversion by aerobic bacteria of dissolved and suspended solids of sewage into particles that will settle. Air bubbles breaking at the air-water interface will aerosolize bacteria that concentrate in the uppermost microlayer. The microbiological output of a plant in New York City with such a system was monitored. Samples of the gaseous effluent were collected inside the aeration building, inside the building's stack, 300 meters upwind (background sampler), and 300 meters downwind (test sampler), using Andersen samplers. Among the genera identified in the atmosphere in and around the plant were Mycobacterium, Klebsiella, and Streptococcus, all potentially pathogenic. The disinfection power of ozone, which is generally used for odor control, was also tested. Samples were taken from the ozone mixing chamber in the stack of the thickentng tank building. No significant difference in general bacterial counts could be detected at different levels of ozone production. It appears that in the air, ozone is an ineffective bactericidal agent. Results in this preliminary study demonstrate the need to evaluate the hazard of microbial aerosols generated by sewage treatment plants similar to the one studied. The possibility of such hazards is of special interest where facilities are located upwind of populations especially susceptible to infections, because of age of debility. Correlations with epidemiologic data are indicated. PMID:814569

  7. Tank vapor sampling and analysis data package for tank 241-C-106 waste retrieval sluicing system process test phase III

    SciTech Connect

    LOCKREM, L.L.

    1999-08-13

    This data package presents sampling data and analytical results from the March 28, 1999, vapor sampling of Hanford Site single-shell tank 241-C-106 during active sluicing. Samples were obtained from the 296-C-006 ventilation system stack and ambient air at several locations. Characterization Project Operations (CPO) was responsible for the collection of all SUMMATM canister samples. The Special Analytical Support (SAS) vapor team was responsible for the collection of all triple sorbent trap (TST), sorbent tube train (STT), polyurethane foam (PUF), and particulate filter samples collected at the 296-C-006 stack. The SAS vapor team used the non-electrical vapor sampling (NEVS) system to collect samples of the air, gases, and vapors from the 296-C-006 stack. The SAS vapor team collected and analyzed these samples for Lockheed Martin Hanford Corporation (LMHC) and Tank Waste Remediation System (TWRS) in accordance with the sampling and analytical requirements specified in the Waste Retrieval Sluicing System Vapor Sampling and Analysis Plan (SAP) for Evaluation of Organic Emissions, Process Test Phase III, HNF-4212, Rev. 0-A, (LMHC, 1999). All samples were stored in a secured Radioactive Materials Area (RMA) until the samples were radiologically released and received by SAS for analysis. The Waste Sampling and Characterization Facility (WSCF) performed the radiological analyses. The samples were received on April 5, 1999.

  8. Manifold gasket accommodating differential movement of fuel cell stack

    DOEpatents

    Kelley, Dana A.; Farooque, Mohammad

    2007-11-13

    A gasket for use in a fuel cell system having at least one externally manifolded fuel cell stack, for sealing the manifold edge and the stack face. In accordance with the present invention, the gasket accommodates differential movement between the stack and manifold by promoting slippage at interfaces between the gasket and the dielectric and between the gasket and the stack face.

  9. Sedimentation stacking diagram of binary colloidal mixtures and bulk phases in the plane of chemical potentials.

    PubMed

    de las Heras, Daniel; Schmidt, Matthias

    2015-05-20

    We give a full account of a recently proposed theory that explicitly relates the bulk phase diagram of a binary colloidal mixture to its phase stacking phenomenology under gravity (de las Heras and Schmidt 2013 Soft Matter 9 8636). As we demonstrate, the full set of possible phase stacking sequences in sedimentation-diffusion equilibrium originates from straight lines (sedimentation paths) in the chemical potential representation of the bulk phase diagram. From the analysis of various standard topologies of bulk phase diagrams, we conclude that the corresponding sedimentation stacking diagrams can be very rich, even more so when finite sample height is taken into account. We apply the theory to obtain the stacking diagram of a mixture of nonadsorbing polymers and colloids. We also present a catalog of generic phase diagrams in the plane of chemical potentials in order to facilitate the practical application of our concept, which also generalizes to multi-component mixtures.

  10. Fungal melanins differ in planar stacking distances.

    PubMed

    Casadevall, Arturo; Nakouzi, Antonio; Crippa, Pier R; Eisner, Melvin

    2012-01-01

    Melanins are notoriously difficult to study because they are amorphous, insoluble and often associated with other biological materials. Consequently, there is a dearth of structural techniques to study this enigmatic pigment. Current models of melanin structure envision the stacking of planar structures. X ray diffraction has historically been used to deduce stacking parameters. In this study we used X ray diffraction to analyze melanins derived from Cryptococcus neoformans, Aspergillus niger, Wangiella dermatitides and Coprinus comatus. Analysis of melanin in melanized C. neoformans encapsulated cells was precluded by the fortuitous finding that the capsular polysaccharide had a diffraction spectrum that was similar to that of isolated melanin. The capsular polysaccharide spectrum was dominated by a broad non-Bragg feature consistent with origin from a repeating structural motif that may arise from inter-molecular interactions and/or possibly gel organization. Hence, we isolated melanin from each fungal species and compared diffraction parameters. The results show that the inferred stacking distances of fungal melanins differ from that reported for synthetic melanin and neuromelanin, occupying intermediate position between these other melanins. These results suggest that all melanins have a fundamental diffracting unit composed of planar graphitic assemblies that can differ in stacking distance. The stacking peak appears to be a distinguishing universal feature of melanins that may be of use in characterizing these enigmatic pigments.

  11. Enhanced dynamical stability with harmonic slip stacking

    DOE PAGES

    Eldred, Jeffrey; Zwaska, Robert

    2016-10-26

    We develop a configuration of radio-frequency (rf) cavities to dramatically improve the performance of slip-stacking. Slip-stacking is an accumulation technique used at Fermilab to nearly double proton intensity by maintaining two beams of different momenta in the same storage ring. The two particle beams are longitudinally focused in the Recycler by two 53 MHz 100 kV rf cavities with a small frequency difference between them. We propose an additional 106 MHz 20 kV rf cavity with a frequency at the double the average of the upper and lower main rf frequencies. We show the harmonic rf cavity cancels out themore » resonances generated between the two main rf cavities and we derive the relationship between the harmonic rf voltage and the main rf voltage. We find the area factors that can be used to calculate the available phase space area for any set of beam parameters without individual simulation. We establish Booster beam quality requirements to achieve 99\\% slip-stacking efficiency. We measure the longitudinal distribution of the Booster beam and use it to generate a realistic beam model for slip-stacking simulation. In conclusion, we demonstrate that the harmonic rf cavity can not only reduce particle loss during slip-stacking, but also reduce the final longitudinal emittance.« less

  12. Fungal Melanins Differ in Planar Stacking Distances

    PubMed Central

    Casadevall, Arturo; Nakouzi, Antonio; Crippa, Pier R.; Eisner, Melvin

    2012-01-01

    Melanins are notoriously difficult to study because they are amorphous, insoluble and often associated with other biological materials. Consequently, there is a dearth of structural techniques to study this enigmatic pigment. Current models of melanin structure envision the stacking of planar structures. X ray diffraction has historically been used to deduce stacking parameters. In this study we used X ray diffraction to analyze melanins derived from Cryptococcus neoformans, Aspergillus niger, Wangiella dermatitides and Coprinus comatus. Analysis of melanin in melanized C. neoformans encapsulated cells was precluded by the fortuitous finding that the capsular polysaccharide had a diffraction spectrum that was similar to that of isolated melanin. The capsular polysaccharide spectrum was dominated by a broad non-Bragg feature consistent with origin from a repeating structural motif that may arise from inter-molecular interactions and/or possibly gel organization. Hence, we isolated melanin from each fungal species and compared diffraction parameters. The results show that the inferred stacking distances of fungal melanins differ from that reported for synthetic melanin and neuromelanin, occupying intermediate position between these other melanins. These results suggest that all melanins have a fundamental diffracting unit composed of planar graphitic assemblies that can differ in stacking distance. The stacking peak appears to be a distinguishing universal feature of melanins that may be of use in characterizing these enigmatic pigments. PMID:22359541

  13. Enhanced dynamical stability with harmonic slip stacking

    NASA Astrophysics Data System (ADS)

    Eldred, Jeffrey; Zwaska, Robert

    2016-10-01

    We develop a configuration of radio-frequency (rf) cavities to dramatically improve the performance of slip stacking. Slip stacking is an accumulation technique used at Fermilab to nearly double proton intensity by maintaining two beams of different momenta in the same storage ring. The two particle beams are longitudinally focused in the Recycler by two 53 MHz 100 kV rf cavities with a small frequency difference between them. We propose an additional 106 MHz 20 kV rf cavity with a frequency at the double the average of the upper and lower main rf frequencies. We show the harmonic rf cavity cancels out the resonances generated between the two main rf cavities and we derive the relationship between the harmonic rf voltage and the main rf voltage. We find the area factors that can be used to calculate the available phase space area for any set of beam parameters without individual simulation. We establish Booster beam quality requirements to achieve 99% slip stacking efficiency. We measure the longitudinal distribution of the Booster beam and use it to generate a realistic beam model for slip stacking simulation. We demonstrate that the harmonic rf cavity can not only reduce particle loss during slip stacking, but also reduce the final longitudinal emittance.

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

    SciTech Connect

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

    2012-06-01

    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.

  15. Inflatable containment diaphragm for sealing and removing stacks

    DOEpatents

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

    1993-04-13

    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.

  16. An integrated modeling approach for temperature driven water transport in a polymer electrolyte fuel cell stack after shutdown

    NASA Astrophysics Data System (ADS)

    Khandelwal, Manish; Mench, M. M.

    The concept of using controlled temperature gradients to non-parasitically remove excess water from porous media during PEFC stack shutdown has been numerically investigated. An integrated modeling approach focusing both at stack and single cell level is presented. The stack thermal model is developed to obtain detailed temperature distribution across the PEFC stack. The two-phase unit fuel cell model is developed to investigate the detailed water and thermal transport in the PEFC components after shutdown, which for the first time includes thermo-osmotic flow in the membrane. The model accounts for capillary and phase-change induced flow in the porous media, and thermo-osmotic and diffusive flow in the polymer membrane. The single cell model is used to estimate the local water distribution with land or channel boundary condition, and the experimentally validated stack thermal model provided the transient temperature boundary conditions. Two different stack designs are compared to quantify the residual water in the stack. Model results indicate that a favorable temperature gradient can be formed in the stack to enhance the water drainage rate, esp. at anode end cell locations, where freeze/thaw damage has been observed to occur.

  17. TESTING FOR CPT VIOLATION IN Bstack">0stack">s SEMILEPTONIC DECAYS

    NASA Astrophysics Data System (ADS)

    Kooten, R. Van

    2014-01-01

    A DØ analysis measuring the charge asymmetry Astack">bstack">sl of like-sign dimuon events due to semileptonic b-hadron decays at the Fermilab Tevatron Collider has shown indications of possible anomalous CP violation in the mixing of neutral B mesons. This result has been used to extract the first senstivity to CPT violation in the Bstack">0stack">s system. An analysis to explore further this anomaly by specifically measuring the semileptonic charge asymmetry, astack">sstack">sl, in Bstack">0stack">s decays is described, as well as how a variant of this analysis can be used to explore a larger set of CPT-violating parameters in the Bstack">0stack">s system for the first time.

  18. Fuel cell stack monitoring and system control

    DOEpatents

    Keskula, Donald H.; Doan, Tien M.; Clingerman, Bruce J.

    2005-01-25

    A control method for monitoring a fuel cell stack in a fuel cell system in which the actual voltage and actual current from the fuel cell stack are monitored. A preestablished relationship between voltage and current over the operating range of the fuel cell is established. A variance value between the actual measured voltage and the expected voltage magnitude for a given actual measured current is calculated and compared with a predetermined allowable variance. An output is generated if the calculated variance value exceeds the predetermined variance. The predetermined voltage-current for the fuel cell is symbolized as a polarization curve at given operating conditions of the fuel cell. Other polarization curves may be generated and used for fuel cell stack monitoring based on different operating pressures, temperatures, hydrogen quantities.

  19. Progress of MCFC stack technology at Toshiba

    SciTech Connect

    Hori, M.; Hayashi, T.; Shimizu, Y.

    1996-12-31

    Toshiba is working on the development of MCFC stack technology; improvement of cell characteristics, and establishment of separator technology. For the cell technology, Toshiba has concentrated on both the restraints of NiO cathode dissolution and electrolyte loss from cells, which are the critical issues to extend cell life in MCFC, and great progress has been made. On the other hand, recognizing that the separator is one of key elements in accomplishing reliable and cost-competitive MCFC stacks, Toshiba has been accelerating the technology establishment and verification of an advanced type separator. A sub-scale stack with such a separator was provided for an electric generating test, and has been operated for more than 10,000 hours. This paper presents several topics obtained through the technical activities in the MCFC field at Toshiba.

  20. A stack of cards rebuilt with calculus

    NASA Astrophysics Data System (ADS)

    Kazachkov, Alexander; Kireš, Marián

    2017-07-01

    Previous work covers building a tower from a stack of homogeneous rectangular plates, each with a maximum shift in displacement. We suggest using plates shaped as curvilinear triangles bounded by segments of power-law functions. The masses of the plates and the position of their center of mass are calculated and measured experimentally after cutting them out from cardboard and aluminum sheets. A computer simulation of the displacement towers is combined with their live building. Individual maximum shifts of the plates in the stack prove to be much bigger the higher the power coefficient of the boundary curves. The resulting total overhang of such a displacement tower may exceed that of a stack of traditionally used homogeneous rectangular cards.

  1. Radiation Tolerant Intelligent Memory Stack (RTIMS)

    NASA Technical Reports Server (NTRS)

    Ng, Tak-kwong; Herath, Jeffrey A.

    2006-01-01

    The Radiation Tolerant Intelligent Memory Stack (RTIMS), suitable for both geostationary and low earth orbit missions, has been developed. The memory module is fully functional and undergoing environmental and radiation characterization. A self-contained flight-like module is expected to be completed in 2006. RTIMS provides reconfigurable circuitry and 2 gigabits of error corrected or 1 gigabit of triple redundant digital memory in a small package. RTIMS utilizes circuit stacking of heterogeneous components and radiation shielding technologies. A reprogrammable field programmable gate array (FPGA), six synchronous dynamic random access memories, linear regulator, and the radiation mitigation circuitries are stacked into a module of 42.7mm x 42.7mm x 13.00mm. Triple module redundancy, current limiting, configuration scrubbing, and single event function interrupt detection are employed to mitigate radiation effects. The mitigation techniques significantly simplify system design. RTIMS is well suited for deployment in real-time data processing, reconfigurable computing, and memory intensive applications.

  2. High frequency model of stacked film capacitors

    NASA Astrophysics Data System (ADS)

    Talbert, T.; Joubert, C.; Daude, N.; Glaize, C.

    2001-11-01

    Polypropylene metallized capacitors are of general use in power electronics because of their reliability, their self-healing capabilities, and their low price. Though the behavior of metallized coiled capacitors has been discussed, no work has been carried out on stacked and flattened metallized capacitors. The purpose of this article is to suggest an analytical model of resonance frequency, stray inductance and impedance of stacked capacitors. We first solve the equation of propagation of the magnetic potential vector (A) in the dielectric of an homogeneous material. Then, we suggest an original method of resolution, like the one used for resonant cavities, in order to present an analytical solution of the problem. Finally, we give some experimental results proving that the physical knowledge of the parameters of the capacitor (dimension of the component, and material constants), enables us to calculate an analytical model of resonance frequency, stray inductance and impedance of stacked capacitors.

  3. The Stack: A New Bacterial Structure Analyzed in the Antarctic Bacterium Pseudomonas deceptionensis M1T by Transmission Electron Microscopy and Tomography

    PubMed Central

    Delgado, Lidia; Carrión, Ornella; Martínez, Gema; López-Iglesias, Carmen; Mercadé, Elena

    2013-01-01

    In recent years, improvements in transmission electron microscopy (TEM) techniques and the use of tomography have provided a more accurate view of the complexity of the ultrastructure of prokaryotic cells. Cryoimmobilization of specimens by rapid cooling followed by freeze substitution (FS) and sectioning, freeze fracture (FF) and observation of replica, or cryoelectron microscopy of vitreous sections (CEMOVIS) now allow visualization of biological samples close to their native state, enabling us to refine our knowledge of already known bacterial structures and to discover new ones. Application of these techniques to the new Antarctic cold-adapted bacterium Pseudomonasdeceptionensis M1T has demonstrated the existence of a previously undescribed cytoplasmic structure that does not correspond to known bacterial inclusion bodies or membranous formations. This structure, which we term a “stack”, was mainly visualized in slow growing cultures of P. deceptionensis M1T and can be described as a set of stacked membranous discs usually arranged perpendicularly to the cell membrane, but not continuous with it, and found in variable number in different locations within the cell. Regardless of their position, stacks were mostly observed very close to DNA fibers. Stacks are not exclusive to P. deceptionensis M1T and were also visualized in slow-growing cultures of other bacteria. This new structure deserves further study using cryoelectron tomography to refine its configuration and to establish whether its function could be related to chromosome dynamics. PMID:24039905

  4. Fuel cell stack monitoring and system control

    DOEpatents

    Keskula, Donald H.; Doan, Tien M.; Clingerman, Bruce J.

    2004-02-17

    A control method for monitoring a fuel cell stack in a fuel cell system in which the actual voltage and actual current from the fuel cell stack are monitored. A preestablished relationship between voltage and current over the operating range of the fuel cell is established. A variance value between the actual measured voltage and the expected voltage magnitude for a given actual measured current is calculated and compared with a predetermined allowable variance. An output is generated if the calculated variance value exceeds the predetermined variance. The predetermined voltage-current for the fuel cell is symbolized as a polarization curve at given operating conditions of the fuel cell.

  5. Three wafer stacking for 3D integration.

    SciTech Connect

    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

    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.

  6. Nonlinearly stacked low noise turbofan stator

    NASA Technical Reports Server (NTRS)

    Schuster, William B. (Inventor); Kontos, Karen B. (Inventor); Weir, Donald S. (Inventor); Nolcheff, Nick A. (Inventor); Gunaraj, John A. (Inventor)

    2009-01-01

    A nonlinearly stacked low noise turbofan stator vane having a characteristic curve that is characterized by a nonlinear sweep and a nonlinear lean is provided. 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 rotor-stator and rotor-strut interaction noise while maintaining the aerodynamic and mechanical performance of the vane. The nonlinearly stacked low noise turbofan stator vane reduces noise associated with the fan stage of turbomachinery to improve environmental compatibility.

  7. Super-resolution and nonlinear absorption with metallodielectric stacks

    NASA Astrophysics Data System (ADS)

    Katte, Nkorni

    We investigate sub-wavelength imaging, i.e. super-resolution, in metal-dielectric film systems, which are simply referred to as metallodielectrics. Our simulations incorporate experimentally derived material dielectric dispersion properties across the visible region. For demonstration purposes we designed metallodielectric stacks for super-resolution containing GaP and TiO2, dielectric films, and either Ag or Au as the metallic materials. Using the known optical properties of the constituent materials found designs that could be good candidates for super-resolution. We did not have the resources to fabricate these samples; however, based on our computer simulations we are confident that the designed samples would produce super-resolution approaching one-twentieth of a wavelength in air. We examined for the first time the broad bandwidth of the super-resolution phenomenon in metallodielectrics. We validate the results using the finite element method (FEM) and the transfer matrix method (TMM). We also show that the measurement of super-resolution is highly dependent on the distance of the probe from the exit surface; high resolution at the exit plane can quickly decay with a few tens of nanometers when high resolution is sought. Secondly we numerically studied the nonlinear optical transmission of an optical beam through heterogeneous metallodielectric stacks under the action of nonlinear absorption. One film layer is a metal and the other layer is a dielectric; the heterogeneous material is called a metallodielectric stack (MDS). In these studies we also used applied FEM with two-dimensional transverse effects and TMM simulation techniques. Our samples consisted of Ag/ZnS, Ag/SiO 2 and Cu/ZnS. We numerically simulate using two transverse dimensions in our FEM codes, Z-scan experiments for two different MDS designs and draw general observations from these cases. We experimentally examined the nonlinear absorption effect in samples of Ag/SiO2 when irradiated by a

  8. Testing gravity with the stacked phase space around galaxy clusters.

    PubMed

    Lam, Tsz Yan; Nishimichi, Takahiro; Schmidt, Fabian; Takada, Masahiro

    2012-08-03

    In general relativity, the average velocity field of dark matter around galaxy clusters is uniquely determined by the mass profile. The latter can be measured through weak lensing. We propose a new method of measuring the velocity field (phase space density) by stacking redshifts of surrounding galaxies from a spectroscopic sample. In combination with lensing, this yields a direct test of gravity on scales of 1-30 Mpc. Using N-body simulations, we show that this method can improve upon current constraints on f(R) and Dvali-Gabadadze-Porrati model parameters by several orders of magnitude when applied to upcoming imaging and redshift surveys.

  9. Magnetic Properties of the Stack of HTSC Tapes in a Wide Temperature Range

    NASA Astrophysics Data System (ADS)

    Rudnev, Igor; Abin, Dmitriy; Osipov, Maxim; Pokrovskiy, Sergey; Ermolaev, Yuriy; Mineev, Nikolay

    The trapped field strength of HTSC stacks were measured in the temperature range T=4-80 K and dc magnetic fields up to 8 Т. A single 12 mm by 12 mm square samples were cut from commercial (RE)BCO tape 12 mm wide and then stacked together. The number of layers in the stacks was varied from n=5 to n=250. Trapped field strength was measured by means of Hall probe which was placed directly on the stacks surface. The dependences of remnant field strength Brem on number of layers in the stacks at different temperature Brem (n) as well as on temperature dependences Brem (T) at various n were obtained. It was found that Brem (n) dependences have a nonlinear character with a tendency to saturation for n > 60. The maximum remnant (trapped) field was found to be more than 2.5 Т at T=4 К. The relaxation of trapped field was studied also and it was determined that the rate of relaxation processes tends to decrease with the increase in a number of tapes in the stack. The correlation between dependency Brem (n) and dependency of magnetic levitation force measured at T=77 K at zero field cooling were found.

  10. Stacking Structures of Few-Layer Graphene Revealed by Phase-Sensitive Infrared Nanoscopy.

    PubMed

    Kim, Deok-Soo; Kwon, Hyuksang; Nikitin, Alexey Yu; Ahn, Seongjin; Martín-Moreno, Luis; García-Vidal, Francisco J; Ryu, Sunmin; Min, Hongki; Kim, Zee Hwan

    2015-07-28

    The stacking orders in few-layer graphene (FLG) strongly influences the electronic properties of the material. To explore the stacking-specific properties of FLG in detail, one needs powerful microscopy techniques that visualize stacking domains with sufficient spatial resolution. We demonstrate that infrared (IR) scattering scanning near-field optical microscopy (sSNOM) directly maps out the stacking domains of FLG with a nanometric resolution, based on the stacking-specific IR conductivities of FLG. The intensity and phase contrasts of sSNOM are compared with the sSNOM contrast model, which is based on the dipolar tip-sample coupling and the theoretical conductivity spectra of FLG, allowing a clear assignment of each FLG domain as Bernal, rhombohedral, or intermediate stacks for tri-, tetra-, and pentalayer graphene. The method offers 10-100 times better spatial resolution than the far-field Raman and infrared spectroscopic methods, yet it allows far more experimental flexibility than the scanning tunneling microscopy and electron microscopy.

  11. Type A verification report for the high flux beam reactor stack and grounds, Brookhaven National Laboratory, Upton, New York

    SciTech Connect

    Harpenau, Evan M.

    2012-01-13

    The U.S. Department of Energy (DOE) Order 458.1 requires independent verification (IV) of DOE cleanup projects (DOE 2011). The Oak Ridge Institute for Science and Education (ORISE) has been designated as the responsible organization for IV of the High Flux Beam Reactor (HFBR) Stack and Grounds area at Brookhaven National Laboratory (BNL) in Upton, New York. The IV evaluation may consist of an in-process inspection with document and data reviews (Type A Verification) or a confirmatory survey of the site (Type B Verification). DOE and ORISE determined that a Type A verification of the documents and data for the HFBR Stack and Grounds: Survey Units (SU) 6, 7, and 8 was appropriate based on the initial survey unit classification, the walkover surveys, and the final analytical results provided by the Brookhaven Science Associates (BSA). The HFBR Stack and Grounds surveys began in June 2011 and were completed in September 2011. Survey activities by BSA included gamma walkover scans and sampling of the as-left soils in accordance with the BSA Work Procedure (BNL 2010a). The Field Sampling Plan - Stack and Remaining HFBR Outside Areas (FSP) stated that gamma walk-over surveys would be conducted with a bare sodium iodide (NaI) detector, and a collimated detector would be used to check areas with elevated count rates to locate the source of the high readings (BNL 2010b). BSA used the Mult- Agency Radiation Survey and Site Investigation Manual (MARSSIM) principles for determining the classifications of each survey unit. Therefore, SUs 6 and 7 were identified as Class 1 and SU 8 was deemed Class 2 (BNL 2010b). Gamma walkover surveys of SUs 6, 7, and 8 were completed using a 2X2 NaI detector coupled to a data-logger with a global positioning system (GPS). The 100% scan surveys conducted prior to the final status survey (FSS) sampling identified two general soil areas and two isolated soil locations with elevated radioactivity. The general areas of elevated activity identified

  12. Generalized approach to design multi-layer stacks for enhanced optical detectability of ultrathin layers

    NASA Astrophysics Data System (ADS)

    Hutzler, A.; Matthus, C. D.; Rommel, M.; Frey, L.

    2017-01-01

    The optical detectability of ultrathin conductive films (down to one atomic layer) can be enhanced by choosing distinct layer-stacks. A simple analytical approach using the transfer matrix method is applied for calculating the reflectance of arbitrary multi-layer stack systems with and without the ultrathin layer of interest on top in a wide wavelength range, including both the visible spectrum and the ultraviolet spectrum. Then, the detectability defined by the Michelson contrast was calculated. Performing these calculations for thickness variations of the individual layers in the stack allows determining optimum layer thicknesses, e.g., maximum overall contrast or maximum contrast for a given wavelength. To demonstrate the validity of the methodology, two thin film stacks were investigated, which use p-type silicon as a substrate material and partially covered by a single-layer graphene as a top layer. For each stack, two samples with different layer thicknesses were fabricated and their experimentally determined reflectance was compared to the calculated values. The first system consists of a single SiO2 layer with a thickness of 147 nm and 304 nm, respectively, and the second is a double layer stack consisting of a Si3N4 layer with a thickness of 54 nm and 195 nm, respectively, on top of an 11 nm SiO2 film. The Michelson contrast of single-layer graphene flakes on the latter layer stacks becomes very high (absolute value of more than 0.3) in the visible wavelength range. Additionally, in the UV-B range a large difference in the reflection of selected SiO2 layer thicknesses on silicon substrates with and without single-layer graphene on top is found with a decrease in the measured reflectance of up to 33%. The measured and calculated values showed a high conformity suggesting this approach usable for the calculation of reflectance and transmittance properties of arbitrary layer stack systems including thin conductive layers.

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

    NASA Astrophysics Data System (ADS)

    Subramani, Shanmugan; Devarajan, Mutharasu; Ibrahim, Kamarulazizi

    2012-06-01

    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.

  14. Investigations of stacking fault density in perpendicular recording media

    SciTech Connect

    Piramanayagam, S. N. Varghese, Binni; Yang, Yi; Kiat Lee, Wee; Khume Tan, Hang

    2014-06-28

    In magnetic recording media, the grains or clusters reverse their magnetization over a range of reversal field, resulting in a switching field distribution. In order to achieve high areal densities, it is desirable to understand and minimize such a distribution. Clusters of grains which contain stacking faults (SF) or fcc phase have lower anisotropy, an order lower than those without them. It is believed that such low anisotropy regions reverse their magnetization at a much lower reversal field than the rest of the material with a larger anisotropy. Such clusters/grains cause recording performance deterioration, such as adjacent track erasure and dc noise. Therefore, the observation of clusters that reverse at very low reversal fields (nucleation sites, NS) could give information on the noise and the adjacent track erasure. Potentially, the observed clusters could also provide information on the SF. In this paper, we study the reversal of nucleation sites in granular perpendicular media based on a magnetic force microscope (MFM) methodology and validate the observations with high resolution cross-section transmission electron microscopy (HRTEM) measurements. Samples, wherein a high anisotropy CoPt layer was introduced to control the NS or SF in a systematic way, were evaluated by MFM, TEM, and magnetometry. The magnetic properties indicated that the thickness of the CoPt layer results in an increase of nucleation sites. TEM measurements indicated a correlation between the thickness of CoPt layer and the stacking fault density. A clear correlation was also observed between the MFM results, TEM observations, and the coercivity and nucleation field of the samples, validating the effectiveness of the proposed method in evaluating the nucleation sites which potentially arise from stacking faults.

  15. Revisiting Stacking Fault Energy of Steels

    NASA Astrophysics Data System (ADS)

    Das, Arpan

    2016-02-01

    The stacking fault energy plays an important role in the transition of deformation microstructure. This energy is strongly dependent on the concentration of alloying elements and the temperature under which the alloy is exposed. Extensive literature review has been carried out and investigated that there are inconsistencies in findings on the influence of alloying elements on stacking fault energy. This may be attributed to the differences in chemical compositions, inaccuracy in measurements, and the methodology applied for evaluating the stacking fault energy. In the present research, a Bayesian neural network model is created to correlate the complex relationship between the extent of stacking fault energy with its influencing parameters in different austenitic grade steels. The model has been applied to confirm that the predictions are reasonable in the context of metallurgical principles and other data published in the open literature. In addition, it has been possible to estimate the isolated influence of particular variables such as nickel concentration, which exactly cannot in practice be varied independently. This demonstrates the ability of the method to investigate a new phenomenon in cases where the information cannot be accessed experimentally.

  16. Average Transmission Probability of a Random Stack

    ERIC Educational Resources Information Center

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

    2010-01-01

    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…

  17. Explosive demolition of K East Reactor Stack

    ScienceCinema

    None

    2016-07-12

    Using $420,000 in Recovery Act funds, the Department of Energy and contractor CH2M HILL Plateau Remediation Company topped off four months of preparations when they safely demolished the exhaust stack at the K East Reactor and equipment inside the reactor building on July 23, 2010.

  18. Arrays of stacked metal coordination compounds

    DOEpatents

    Bulkowski, J.E.

    1986-10-21

    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.

  19. A Stack of Cards Rebuilt with Calculus

    ERIC Educational Resources Information Center

    Kazachkov, Alexander; Kireš, Marián

    2017-01-01

    Previous work covers building a tower from a stack of homogeneous rectangular plates, each with a maximum shift in displacement. We suggest using plates shaped as curvilinear triangles bounded by segments of power-law functions. The masses of the plates and the position of their center of mass are calculated and measured experimentally after…

  20. 49 CFR 178.606 - Stacking test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... with specific gravities different from that of the liquid to be transported, the force must be calculated based on the specific gravity that will be marked on the packaging. The minimum height of the... number of containers that, when stacked, reach a height of 3 meters. s = specific gravity of lading. w...

  1. Explosive demolition of K East Reactor Stack

    SciTech Connect

    2010-07-26

    Using $420,000 in Recovery Act funds, the Department of Energy and contractor CH2M HILL Plateau Remediation Company topped off four months of preparations when they safely demolished the exhaust stack at the K East Reactor and equipment inside the reactor building on July 23, 2010.

  2. Removing Sulphur Dioxide From Stack Gases

    ERIC Educational Resources Information Center

    Slack, A. V.

    1973-01-01

    Process types, process concepts, claims and counterclaims, cost factors, and the level of developed technology for sulfur dioxide control in stack gases are focused upon and evaluated. Wet and dry processes as well as recovery and throwaway processes are compared. (BL)

  3. Stack Gas Scrubber Makes the Grade

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1975

    1975-01-01

    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)

  4. Scaling the CERN OpenStack cloud

    NASA Astrophysics Data System (ADS)

    Bell, T.; Bompastor, B.; Bukowiec, S.; Castro Leon, J.; Denis, M. K.; van Eldik, J.; Fermin Lobo, M.; Fernandez Alvarez, L.; Fernandez Rodriguez, D.; Marino, A.; Moreira, B.; Noel, B.; Oulevey, T.; Takase, W.; Wiebalck, A.; Zilli, S.

    2015-12-01

    CERN has been running a production OpenStack cloud since July 2013 to support physics computing and infrastructure services for the site. In the past year, CERN Cloud Infrastructure has seen a constant increase in nodes, virtual machines, users and projects. This paper will present what has been done in order to make the CERN cloud infrastructure scale out.

  5. Average Transmission Probability of a Random Stack

    ERIC Educational Resources Information Center

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

    2010-01-01

    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…

  6. 49 CFR 178.606 - Stacking test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... with specific gravities different from that of the liquid to be transported, the force must be calculated based on the specific gravity that will be marked on the packaging. The minimum height of the... number of containers that, when stacked, reach a height of 3 meters. s = specific gravity of lading....

  7. Arrays of stacked metal coordination compounds

    DOEpatents

    Bulkowski, John E.

    1986-01-01

    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.

  8. Removing Sulphur Dioxide From Stack Gases

    ERIC Educational Resources Information Center

    Slack, A. V.

    1973-01-01

    Process types, process concepts, claims and counterclaims, cost factors, and the level of developed technology for sulfur dioxide control in stack gases are focused upon and evaluated. Wet and dry processes as well as recovery and throwaway processes are compared. (BL)

  9. Stack Gas Scrubber Makes the Grade

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1975

    1975-01-01

    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)

  10. Detection of primary and secondary cosmic ray particles aboard the ISS using SSNTD stacks.

    PubMed

    Pálfalvi, J K; Akatov, Yu; Szabó, J; Sajó-Bohus, L; Eördögh, I

    2006-01-01

    To study the radiation environment inside the International Space Station, solid state nuclear track detector stacks were used. Within the BRADOS experiments, Phase 1, seven stacks were exposed at different locations of the Russian segment 'Zvezda' for 248 days in 2001. It was supposed that the radiation field inside the ISS was composed from primary cosmic ray particles penetrating the wall of the ISS and secondaries, mainly neutrons induced by primaries in the wall and other structural materials surrounding the detectors. Based on the calibration made by utilising the high energy neutron reference field CERF at CERN (Geneva, Switzerland), the tracks induced by neutrons were separated from those induced by primary particles. Thus, the stacks, on one hand, provided the secondary neutron ambient dose equivalent. On the other hand, from the analysis of the rest of the tracks, the linear energy transfer spectra were computed and the flux and the dose of the primary particles were determined as shown in this paper.

  11. Determination of Fire Enviroment in Stacked Cargo Containers with Radioactive Materials Packages

    SciTech Connect

    Arviso, M.; Bobbe, J.G.; Dukart, R.D.; Koski, J.A.

    1999-05-01

    Results from a Fire Test with a three-by-three stack of standard 6 m long International Standards Organization shipping containers containing combustible fuels and empty radioactive materials packages are reported and discussed. The stack is intended to simulate fire conditions that could occur during on-deck stowage on container cargo ships. The fire is initated by locating the container stack adjacent to a 9.8 x 6 m pool fire. Temperatures of both cargoes (empty and simulated radioactive materials packages) and containers are recorded and reported. Observations on the duration, intensity and spread of the fire are discussed. Based on the results, models for simulation of fire exposure of radioactive materials packages in such fires are suggested.

  12. Evaluation of a stack: A concrete chimney with brick liner

    SciTech Connect

    Joshi, J.R.; Amin, J.A.; Porthouse, R.A.

    1995-12-31

    A 200 ft. tall stack, consisting of a concrete chimney with an independent acid proof brick liner built in the 1950`s, serving the Separations facility at the Savannah River Site (SRS), was evaluated for the performance category 3 (PC3) level of Natural Phenomena Hazards (NPH) effects. The inelastic energy absorption capacity of the concrete chimney was considered in the evaluation of the earthquake resistance, in particular, to compute the F{sub {mu}} factor. The calculated value of F{sub {mu}} exceeded 3.0, while the seismic demand for the PC3 level, using an F{sub {mu}} value of 1.5, was found to be less than the capacity of the concrete chimney. The capacity formulation of ACI 307 was modified to incorporate the effect of an after design opening on the tension side. There are considerable uncertainties in determining the earthquake resistance of the independent brick liner. The critical liner section, located at the bottom of the breeching opening, does not meet the current recommendations. A discussion is provided for the possible acceptable values for the ``Moment Reduction Factor``, R{sub w} or F{sub {mu}} for the liner. Comments are provided on the comparison of stack demands using response spectra (RS) versus time history (TH) analysis, with and without soil structure interaction (SSI) effects.

  13. A thermal stack structure for measurement of fluid flow

    NASA Astrophysics Data System (ADS)

    Zhao, Hao; Mitchell, S. J. N.; Campbell, D. H.; Gamble, Harold S.

    2003-03-01

    A stacked thermal structure for fluid flow sensing has been designed, fabricated, and tested. A double-layer polysilicon process was employed in the fabrication. Flow measurement is based on the transfer of heat from a temperature sensor element to the moving fluid. The undoped or lightly doped polysilicon temperature sensor is located on top of a heavily doped polysilicon heater element. A dielectric layer between the heater and the sensor elements provides both thermal coupling and electrical isolation. In comparison to a hot-wire flow sensor, the heating and sensing functions are separated, allowing the electrical characteristics of each to be optimized. Undoped polysilicon has a large temperature coefficient of resistance (TCR) up to 7 %/K and is thus a preferred material for the sensor. However, heavily doped polysilicon is preferred for the heater due to its lower resistance. The stacked flow sensor structure offers a high thermal sensitivity making it especially suitable for medical applications where the working temperatures are restricted. Flow rates of various fluids can be measured over a wide range. The fabricated flow sensors were used to measure the flow rate of water in the range μl - ml/min and gas (Helium) in the range 10 - 100ml/min.

  14. [Analysis on Mechanism of Rainout Carried by Wet Stack of Thermal Power Plant].

    PubMed

    Ouyang, Li-hua; Zhuang, Ye; Liu, Ke-wei; Chen, Zhen-yu; Gu, Peng

    2015-06-01

    Rainout from wet-stack took placed in many thermal power plants with WFGD system. Research on causes of the rainout is important to solve the problem. The objective of this research is to analyze the mechanism of rainout. Field study was performed to collect experimental data in one thermal power plant, including the amount of desulfurization slurry carried by wet flue gas, liquor condensate from wet duct, and droplets from the wet stack. Source apportionment analysis was carried out based on physical and chemical data of liquid sample and solid sample. The result showed that mist eliminator operated well, which met the performance guarantee value. But the total amount of desulfurization slurry in flue gas and the sulfate concentration in liquid condensate discharge from the wet duct/stack increased. The liquid condensate accumulated in the wet duct/stack led to liquid re-entrainment. In conclusion, the rainout in this power plant was caused by the short of wet ductwork or liquid discharge system, the droplets caused by re-entrainment carried by the saturated gas released from the stack. The main undissolved components of the rainout were composite carbonate and aluminosilicate. Although ash concentration in this WFGD met the regulation criteria, source apportionment analysis showed that fly ash contributed to rainout was accounted for 60%. This percentage value was same as the data of solid particles in the condensate. It is important to optimize the wet ductwork, wet stack liner, liquid collectors and drainage. Avoiding the accumulation from saturated vapor thermal condensation is an effective way to solve the wet stack rainout.

  15. Radiatio Detector Characterization at APO While Stacking pbars in 1999

    SciTech Connect

    Leveling, A.F.; /Fermilab

    2000-02-09

    The Main Injector provided beam for pbar stacking for the first time in 1999 over the period 12/20 to 12/21. The purpose of this memo is to record some observations on the response of various radiation detectors as a function of beam on the pbar targel. The detectors include a Scarecrow in the APO Vault, a Chipmunk just upstream of the APO vault, and a Chipmunk in the water cage adjacent to the Pulsed Magnet pump skid in the water systems cage. In addition, there are air monitors, one sampling in the PreVault enclosure and one sampling at the exhaust stack at the upstream end of lhe PreTarget enclosure. All data was collected by the ACNET system Lumberjack data logger. Beam intensity data was summed over consecutive 10 minute periods and normalized to an hourly intensity. The Chipmunk, Scarecrow, and Air Monitor data are based 10 minute averages taken over periods which coincide with normalized beam intensity.

  16. Effect of stacking method on Salmonella elimination from recycled poultry bedding.

    PubMed

    Bush, Dawn J; Poore, Matthew H; Rogers, Glenn M; Altier, Craig

    2007-02-01

    Recycled poultry bedding (RPB) is a protein and mineral supplement for cattle. Concerns regarding this product have arisen because of the perceived risk of transmitting potentially pathogenic organisms to cattle. This study's primary objective was to assess survival of Salmonella in RPB stacked to a recommended height (2.13 m-DS-RPB), or a height of 0.76 m (SS-RPB). Dialysis bags containing RPB and Salmonella typhimurium were placed throughout stacks. Temperature was monitored daily using thermocouples attached to sample bags. After 21 days, sample bags were recovered. Ammonia analysis was performed from multiple sites in the stacks. Bag contents were cultured to determine viability of the salmonella inoculates. This trial demonstrated a wide variation of temperature within the stacks. Temperature near the edge of stacks changed with ambient temperature. Ammonia concentration in the RPB was highest at the top of the DS-RPB. Salmonella was eliminated in 98.7% of sites, with at least a 5-log reduction in the Salmonella organisms in sites where it was still viable.

  17. Signal Enhancement with Stacked Magnets for High-Resolution Radio Frequency Glow Discharge Mass Spectrometry.

    PubMed

    Wei, Juan; Dong, Jiangli; Zhuo, Shangjun; Qian, Rong; Fang, Yuanxing; Chen, Qiao; Patel, Ekbal

    2017-01-17

    A method for signal enhancement utilizing stacked magnets was introduced into high-resolution radio frequency glow discharge-mass spectrometry (rf-GD-MS) for significantly improved analysis of inorganic materials. Compared to the block magnet, the stacked magnets method was able to achieve 50-59% signal enhancement for typical elements in Y2O3, BSO, and BTN samples. The results indicated that signal was enhanced as the increase of discharge pressure from 1.3 to 8.0 mPa, the increase of rf-power from 10 to 50 W with a frequency of 13.56 MHz, the decrease of sample thickness, and the increase of number of stacked magnets. The possible mechanism for the signal enhancement was further probed using the software "Mechanical APDL (ANSYS) 14.0". It was found that the distinct oscillated magnetic field distribution from the stacked magnets was responsible for signal enhancement, which could extend the movement trajectories of electrons and increase the collisions between the electrons and neutral particles to increase the ionization efficiency. Two NIST samples were used for the validation of the method, and the results suggested that relative errors were within 13% and detection limit for six transverse stacked magnets could reach as low as 0.0082 μg g(-1). Additionally, the stability of the method was also studied. RSD within 15% of the elements in three nonconducting samples could be obtained during the sputtering process. Together, the results showed that the signal enhancement method with stacked magnets could offer great promises in providing a sensitive, stable, and facile solution for analyzing the nonconducting materials.

  18. 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

  19. 40 CFR 52.2384 - Stack height review.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... affected by stack height credits greater than good engineering practice or any other prohibited dispersion... ‘good engineering practice’ stack height or from using ‘other dispersion techniques.’ ” Thus, Vermont...

  20. Single-point representative sampling with shrouded probes

    SciTech Connect

    McFarland, A.R.; Rodgers, J.C.

    1993-08-01

    The Environmental Protection Agency (EPA) prescribed methodologies for sampling radionuclides in air effluents from stacks and ducts at US Department of Energy (DOE) facilities. Requirements include use of EPA Method 1 for the location of sampling sites and use of American National Standards Institute (ANSI) N13.1 for guidance in design of sampling probes and the number of probes at a given site. Application of ANSI N13.1 results in sampling being performed with multiprobe rakes that have as many as 20 probes. There can be substantial losses of aerosol particles in such sampling that will degrade the quality of emission estimates from a nuclear facility. Three alternate methods, technically justified herein, are proposed for effluent sampling. First, a shrouded aerosol sampling probe should replace the sharp-edged elbowed-nozzle recommended by ANSI. This would reduce the losses of aerosol particles in probes and result in the acquisition of more representative aerosol samples. Second, the rakes of multiple probes that are intended to acquire representative samples through spatial coverage should be replaced by a single probe located where contaminant mass and fluid momentum are both well mixed. A representative sample can be obtained from a well-mixed flow. Some effluent flows will need to be engineered to achieve acceptable mixing. Third, sample extraction should be performed at a constant flow rate through a suitable designed shrouded probe rather than at a variable flow rate through isokinetic probes. A shrouded probe is shown to have constant sampling characteristics over a broad range of stack velocities when operated at a fixed flow rate.