Measurement of lung volume in mechanically ventilated monkeys with an ultrasonic flow meter and the nitrogen washout method.

PubMed

Schibler, Andreas; Hammer, Jürg; Isler, Ruedi; Buess, Christian; Newth, Christopher J L

2004-01-01

Measurement of functional residual capacity (FRC) during mechanical ventilation is important to standardise respiratory system compliance and adjust the ventilator settings to optimise lung recruitment. In the present study we compared three methods to measure FRC. The bias flow nitrogen washout technique (FRC(N2MC)), the multiple breath nitrogen washout (FRC(MBNW)) and the multiple breath sulphur-hexafluoride washout using the molar mass signal of an ultrasonic flow meter (FRC(MBSF6)) were compared in six adult monkeys after endotracheal intubation and during spontaneous breathing and mechanical ventilation at three different positive end-expiratory pressure (PEEP) levels of 0, 5 and 10 cmH2O. Animal research laboratory. We found good agreement between all three methods and they all accurately measured changes in FRC when PEEP was increased. The coefficients of variance of the three measurement techniques were in the same range (1.3-9.2%). The measurement of the tracer gas concentration with the molar mass signal of the ultrasonic flow meter provides a good and simple alternative to respiratory mass spectrometer for FRC measurements in ventilated subjects.

LSP simulations of fast ions slowing down in cool magnetized plasma

NASA Astrophysics Data System (ADS)

Evans, Eugene S.; Cohen, Samuel A.

2015-11-01

In MFE devices, rapid transport of fusion products, e.g., tritons and alpha particles, from the plasma core into the scrape-off layer (SOL) could perform the dual roles of energy and ash removal. Through these two processes in the SOL, the fast particle slowing-down time will have a major effect on the energy balance of a fusion reactor and its neutron emissions, topics of great importance. In small field-reversed configuration (FRC) devices, the first-orbit trajectories of most fusion products will traverse the SOL, potentially allowing those particles to deposit their energy in the SOL and eventually be exhausted along the open field lines. However, the dynamics of the fast-ion energy loss processes under conditions expected in the FRC SOL, where the Debye length is greater than the electron gyroradius, are not fully understood. What modifications to the classical slowing down rate are necessary? Will instabilities accelerate the energy loss? We use LSP, a 3D PIC code, to examine the effects of SOL plasma parameters (density, temperature and background magnetic field strength) on the slowing down time of fast ions in a cool plasma with parameters similar to those expected in the SOL of small FRC reactors. This work supported by DOE contract DE-AC02-09CH11466.

Stability and confinement improvement of an oblate field-reversed configuration by using neutral beam injection

NASA Astrophysics Data System (ADS)

T., Ii; Inomoto, M.; Gi, K.; Umezawa, T.; Ito, T.; Kadowaki, K.; Kaminou, Y.; Ono, Y.

2013-07-01

A low-energy, high-current neutral beam injection (NBI) was applied to an oblate field-reversed configuration (FRC) for the first time. The NB fast ions reduce growth rates of low-n modes dangerous for the oblate FRC, extending the FRC lifetime by a factor of 1.2. The reduced loss power of 5 MW is much higher than the NBI power of 0.5 MW, indicating that the NBI not only heats the FRC plasma but also improves its stability and transport properties. The NBI also maintains higher pressure and current density profiles of the FRC, improving its flux and energy decay times by a factor of 2.

Gyrokinetic simulation of driftwave instability in field-reversed configuration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fulton, D. P., E-mail: dfulton@trialphaenergy.com; University of California, Irvine, California 92697; Lau, C. K.

2016-05-15

Following the recent remarkable progress in magnetohydrodynamic (MHD) stability control in the C-2U advanced beam driven field-reversed configuration (FRC), turbulent transport has become one of the foremost obstacles on the path towards an FRC-based fusion reactor. Significant effort has been made to expand kinetic simulation capabilities in FRC magnetic geometry. The recently upgraded Gyrokinetic Toroidal Code (GTC) now accommodates realistic magnetic geometry from the C-2U experiment at Tri Alpha Energy, Inc. and is optimized to efficiently handle the FRC's magnetic field line orientation. Initial electrostatic GTC simulations find that ion-scale instabilities are linearly stable in the FRC core for realisticmore » pressure gradient drives. Estimated instability thresholds from linear GTC simulations are qualitatively consistent with critical gradients determined from experimental Doppler backscattering fluctuation data, which also find ion scale modes to be depressed in the FRC core. Beyond GTC, A New Code (ANC) has been developed to accurately resolve the magnetic field separatrix and address the interaction between the core and scrape-off layer regions, which ultimately determines global plasma confinement in the FRC. The current status of ANC and future development targets are discussed.« less

Gyrokinetic simulation of driftwave instability in field-reversed configuration

NASA Astrophysics Data System (ADS)

Fulton, D. P.; Lau, C. K.; Schmitz, L.; Holod, I.; Lin, Z.; Tajima, T.; Binderbauer, M. W.

2016-05-01

Following the recent remarkable progress in magnetohydrodynamic (MHD) stability control in the C-2U advanced beam driven field-reversed configuration (FRC), turbulent transport has become one of the foremost obstacles on the path towards an FRC-based fusion reactor. Significant effort has been made to expand kinetic simulation capabilities in FRC magnetic geometry. The recently upgraded Gyrokinetic Toroidal Code (GTC) now accommodates realistic magnetic geometry from the C-2U experiment at Tri Alpha Energy, Inc. and is optimized to efficiently handle the FRC's magnetic field line orientation. Initial electrostatic GTC simulations find that ion-scale instabilities are linearly stable in the FRC core for realistic pressure gradient drives. Estimated instability thresholds from linear GTC simulations are qualitatively consistent with critical gradients determined from experimental Doppler backscattering fluctuation data, which also find ion scale modes to be depressed in the FRC core. Beyond GTC, A New Code (ANC) has been developed to accurately resolve the magnetic field separatrix and address the interaction between the core and scrape-off layer regions, which ultimately determines global plasma confinement in the FRC. The current status of ANC and future development targets are discussed.

Gyrokinetic particle simulation of a field reversed configuration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fulton, D. P., E-mail: dfulton@uci.edu; Lau, C. K.; Holod, I.

2016-01-15

Gyrokinetic particle simulation of the field-reversed configuration (FRC) has been developed using the gyrokinetic toroidal code (GTC). The magnetohydrodynamic equilibrium is mapped from cylindrical coordinates to Boozer coordinates for the FRC core and scrape-off layer (SOL), respectively. A field-aligned mesh is constructed for solving self-consistent electric fields using a semi-spectral solver in a partial torus FRC geometry. This new simulation capability has been successfully verified and driftwave instability in the FRC has been studied using the gyrokinetic simulation for the first time. Initial GTC simulations find that in the FRC core, the ion-scale driftwave is stabilized by the large ionmore » gyroradius. In the SOL, the driftwave is unstable on both ion and electron scales.« less

Effect of implant design and bioactive glass coating on biomechanical properties of fiber-reinforced composite implants.

PubMed

Ballo, Ahmed M; Akca, Eralp; Ozen, Tuncer; Moritz, Niko; Lassila, Lippo; Vallittu, Pekka; Närhi, Timo

2014-08-01

This study aimed to evaluate the influence of implant design and bioactive glass (BAG) coating on the response of bone to fiber-reinforced composite (FRC) implants. Three different FRC implant types were manufactured for the study: non-threaded implants with a BAG coating; threaded implants with a BAG coating; and threaded implants with a grit-blasted surface. Thirty-six implants (six implants for each group per time point) were installed in the tibiae of six pigs. After an implantation period of 4 and 12 wk, the implants were retrieved and prepared for micro-computed tomography (micro-CT), push-out testing, and scanning electron microscopy analysis. Micro-CT demonstrated that the screw-threads and implant structure remained undamaged during the installation. The threaded FRC/BAG implants had the highest bone volume after 12 wk of implantation. The push-out strengths of the threaded FRC/BAG implants after 4 and 12 wk (463°N and 676°N, respectively) were significantly higher than those of the threaded FRC implants (416°N and 549°N, respectively) and the nonthreaded FRC/BAG implants (219°N and 430°N, respectively). Statistically significant correlation was found between bone volume and push-out strength values. This study showed that osseointegrated FRC implants can withstand the static loading up to failure without fracture, and that the addition of BAG significantly improves the push-out strength of FRC implants. © 2014 Eur J Oral Sci.

Critical role of CD4 T cells in maintaining lymphoid tissue structure for immune cell homeostasis and reconstitution.

PubMed

Zeng, Ming; Paiardini, Mirko; Engram, Jessica C; Beilman, Greg J; Chipman, Jeffrey G; Schacker, Timothy W; Silvestri, Guido; Haase, Ashley T

2012-08-30

Loss of the fibroblastic reticular cell (FRC) network in lymphoid tissues during HIV-1 infection has been shown to impair the survival of naive T cells and limit immune reconstitution after antiretroviral therapy. What causes this FRC loss is unknown. Because FRC loss correlates with loss of both naive CD4 and CD8 T-cell subsets and decreased lymphotoxin-β, a key factor for maintenance of FRC network, we hypothesized that loss of naive T cells is responsible for loss of the FRC network. To test this hypothesis, we assessed the consequences of antibody-mediated depletion of CD4 and CD8 T cells in rhesus macaques and sooty mangabeys. We found that only CD4 T-cell depletion resulted in FRC loss in both species and that this loss was caused by decreased lymphotoxin-β mainly produced by the CD4 T cells. We further found the same dependence of the FRC network on CD4 T cells in HIV-1-infected patients before and after antiretroviral therapy and in other immunodeficiency conditions, such as CD4 depletion in cancer patients induced by chemotherapy and irradiation. CD4 T cells thus play a central role in the maintenance of lymphoid tissue structure necessary for their own homeostasis and reconstitution.

Flexural properties of fiber reinforced root canal posts.

PubMed

Lassila, Lippo V J; Tanner, Johanna; Le Bell, Anna-Maria; Narva, Katja; Vallittu, Pekka K

2004-01-01

Fiber-reinforced composite (FRC) root canal posts have been introduced to be used instead of metal alloys and ceramics. The aim of this study was to investigate the flexural properties of different types of FRC posts and compare those values with a novel FRC material for dental applications. Seventeen different FRC posts of various brands (Snowpost, Carbopost, Parapost, C-post, Glassix, Carbonite) and diameters, (1.0-2.1 mm) and a continuous unidirectional E-glass FRC polymerized by light activation to a cylindrical form (everStick, diameter 1.5 mm) as a control material were tested. The posts (n=5) were stored at room's humidity or thermocycled (12.000 x, 5 degrees C/55 degrees C) and stored in water for 2 weeks before testing. A three-point bending test (span=10 mm) was used to measure the flexural strength and modulus of FRC post specimens. Analysis of ANOVA revealed that thermocycling, brand of material and diameter of specimen had a significant effect (p<0.001) on the fracture load and flexural strength. The highest flexural strength was obtained with the control material (everStick, 1144.9+/-99.9 MPa). There was a linear relationship between fracture load and diameter of posts for both glass fiber and carbon fiber posts. Thermocycling decreased the flexural modulus of the tested specimens by approximately 10%. Strength and fracture load decreased approximately 18% as a result of thermocycling. Considerable variation can be found in the calculated strength values of the studied post brands. Commercial prefabricated FRC posts showed lower flexural properties than an individually polymerised FRC material.

Formation and sustainment of field reversed configuration (FRC) plasmas by spheromak merging and neutral beam injection

DOE PAGES

Yamada, Masaaki

2016-01-01

This study briefly reviews a compact toroid reactor concept that addresses critical issues for forming, stabilizing and sustaining a field reversed configuration (FRC) with the use of plasma merging, plasma shaping, conducting shells, neutral beam injection (NBI). In this concept, an FRC plasma is generated by the merging of counter-helicity spheromaks produced by inductive discharges and sustained by the use of neutral beam injection (NBI). Plasma shaping, conducting shells, and the NBI would provide stabilization to global MHD modes. Although a specific FRC reactor design is outside the scope of the present paper, an example of a promising FRC reactormore » program is summarized based on the previously developed SPIRIT (Self-organized Plasmas by Induction, Reconnection and Injection Techniques) concept in order to connect this concept to the recently achieved the High Performance FRC plasmas obtained by Tri Alpha Energy [Binderbauer et al, Phys. Plasmas 22,056110, (2015)]. This paper includes a brief summary of the previous concept paper by M. Yamada et al, Plasma Fusion Res. 2, 004 (2007) and the recent experimental results from MRX.« less

Simulation of the target creation through FRC merging for a magneto-inertial fusion concept

NASA Astrophysics Data System (ADS)

Li, Chenguang; Yang, Xianjun

2017-04-01

A two-dimensional magnetohydrodynamics model has been used to simulate the target creation process in a magneto-inertial fusion concept named Magnetized Plasma Fusion Reactor (MPFR) [C. Li and X. Yang, Phys. Plasmas 23, 102702 (2016)], where the target plasma created through Field reversed configuration (FRC) merging was compressed by an imploding liner driven by the pulsed-power driver. In the scheme, two initial FRCs (Field reversed configurations) are translated into the region where FRC merging occurs, bringing out the target plasma ready for compression. The simulations cover the three stages of the target creation process: formation, translation, and merging. The factors affecting the achieved target are analyzed numerically. The magnetic field gradient produced by the conical coils is found to determine how fast the FRC is accelerated to peak velocity and the collision merging occurs. Moreover, it is demonstrated that FRC merging can be realized by real coils with gaps showing nearly identical performance, and the optimized target by FRC merging shows larger internal energy and retained flux, which is more suitable for the MPFR concept.

Formation and sustainment of field reversed configuration (FRC) plasmas by spheromak merging and neutral beam injection

NASA Astrophysics Data System (ADS)

Yamada, Masaaki

2016-03-01

This paper briefly reviews a compact toroid reactor concept that addresses critical issues for forming, stabilizing and sustaining a field reversed configuration (FRC) with the use of plasma merging, plasma shaping, conducting shells, neutral beam injection (NBI). In this concept, an FRC plasma is generated by the merging of counter-helicity spheromaks produced by inductive discharges and sustained by the use of neutral beam injection (NBI). Plasma shaping, conducting shells, and the NBI would provide stabilization to global MHD modes. Although a specific FRC reactor design is outside the scope of the present paper, an example of a promising FRC reactor program is summarized based on the previously developed SPIRIT (Self-organized Plasmas by Induction, Reconnection and Injection Techniques) concept in order to connect this concept to the recently achieved the High Performance FRC plasmas obtained by Tri Alpha Energy [Binderbauer et al, Phys. Plasmas 22,056110, (2015)]. This paper includes a brief summary of the previous concept paper by M. Yamada et al, Plasma Fusion Res. 2, 004 (2007) and the recent experimental results from MRX.

Formation and sustainment of field reversed configuration (FRC) plasmas by spheromak merging and neutral beam injection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamada, Masaaki

2016-03-25

This paper briefly reviews a compact toroid reactor concept that addresses critical issues for forming, stabilizing and sustaining a field reversed configuration (FRC) with the use of plasma merging, plasma shaping, conducting shells, neutral beam injection (NBI). In this concept, an FRC plasma is generated by the merging of counter-helicity spheromaks produced by inductive discharges and sustained by the use of neutral beam injection (NBI). Plasma shaping, conducting shells, and the NBI would provide stabilization to global MHD modes. Although a specific FRC reactor design is outside the scope of the present paper, an example of a promising FRC reactormore » program is summarized based on the previously developed SPIRIT (Self-organized Plasmas by Induction, Reconnection and Injection Techniques) concept in order to connect this concept to the recently achieved the High Performance FRC plasmas obtained by Tri Alpha Energy [Binderbauer et al, Phys. Plasmas 22,056110, (2015)]. This paper includes a brief summary of the previous concept paper by M. Yamada et al, Plasma Fusion Res. 2, 004 (2007) and the recent experimental results from MRX.« less

Hydrostatic weighing at residual volume and functional residual capacity.

PubMed

Thomas, T R; Etheridge, G L

1980-07-01

Hydrostatic weighing (HW) was performed at both residual volume (RV) and functional residual capacity (FRC) to determine if underwater weighing at different lung volumes affected the measurement of body density. Subjects were 43 males, 18-25 yr. Subjects were submerged in the prone position, and the lung volume was measured by helium dilution at the time of the underwater weighing. Underwater weight was first assessed at FRC followed by assessment at RV. Changes in lung volume were accurately reflected in the underwater weight. Body density (D) was not different with the use of the FRC (mean D = 1.0778) or RV (mean D = 1.0781) data. Percent fat values for the FRC and RV data were 9.3 +/- 5.4 and 9.2 +/- 5.1%, respectively, and were not statistically different. The results indicate that the difference between percent fat determinations by HW in the prone position at FRC and RV is negligible. Because measurement of underwater weight at FRC is more comfortable for the subject, this may be the method of choice when the lung volume can be measured during the underwater weighing.

In vitro validation of an ultrasonic flowmeter in order to measure the functional residual capacity in newborns.

PubMed

Wauer, Juliane; Leier, Tim U; Henschen, Matthias; Wauer, Roland R; Schmalisch, Gerd

2003-05-01

Ultrasonic transit-time airflow meters (UFM) allow simultaneous measurements of volume flow V'(t) and molar mass MM(t) of the breathing gas in the mainstream. Consequently, by using a suitable tracer gas the functional residual capacity (FRC) of the lungs can be measured by a gas wash-in/wash-out technique. The aim of this study was to investigate the in vitro accuracy of a multiple-breath wash-in/wash-out technique for FRC measurements using 4% sulphur hexafluoride (SF6) in air. V'(t) and MM(t) were measured with a Spiroson SCIENTIFIC flowmeter (ECO Medics, CH) with 1.3 ml dead space. Linearity of airflow and MM were tested using different tidal volumes (V(T)) and breathing gases with different O2 and SF6 concentrations. To determine the accuracy of FRC measurements SF6 wash-in and wash-out curves from four mechanical lung models (FRC of 22, 53, 102 and 153 ml) were evaluated by the Spiroson. For each model five measurements were performed with a physiological V(T)/FRC ratio of 0.3 and constant respiratory rate of 30 min(-1). The error of measured V(T) (range 4-60 ml) was <2.5%. There was a strong correlation between the measured and calculated MM of different breathing gases (r = 0.989), and the measuring accuracy was better than 1%. The measured FRC of the four models were 20.3, 49.7, 104.3 and 153.4 ml with a coefficient of variation of 16.5%, 4.5%, 4.9% and 3%. Accordingly, for FRC <100 ml the in vitro accuracy was better than 8% and for FRC >100 ml better than 2.5%. The determination of FRC by MM measurements using the UFM is a simple and cost-effective alternative to conventionally used gas analysers with an acceptable accuracy for many clinical purposes.

Framework design and pontics of fiber-reinforced composite fixed dental prostheses - An overview.

PubMed

Perea-Lowery, Leila; Vallittu, Pekka K

2018-05-11

Fiber-reinforced composite (FRC) fixed dental prostheses (FDPs) have shown good performance in clinical applications due to their good mechanical properties and minimally invasive approach. However, typical failure patterns of FRC FDPs are often localized at the pontic site. That reflects the structural considerations at the framework and pontic location that need to be examined when creating these kinds of prostheses. Peer-reviewed articles and other scientific literature were reviewed for providing up-to-date information on how pontics of FRC FDPs can be made. A thorough literature search was done using PubMed and Google Scholar. Two individuals did an assessment of the articles in order to include those related to pontics and framework design of FRC FDPs. The search terms used were "fiber-reinforced dental prosthesis" and "Pontics of fiber-reinforced dental prosthesis". These findings indicate that a cross-sectional fiber design, substructure and thicker pontics made of a variety of materials might reduce failures at the pontic site. The thickness of pontics of FRC FDPs interrelated with the vertical positioning of the FRC framework influences the load-bearing capacities of prostheses of these kinds. The understanding of the factors involved in the fabrication of pontics of FRC FDPs may overcome the drawbacks identified in these prostheses, thus extending their longevity. Copyright © 2018 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Critical role of CD4 T cells in maintaining lymphoid tissue structure for immune cell homeostasis and reconstitution

PubMed Central

Zeng, Ming; Paiardini, Mirko; Engram, Jessica C.; Beilman, Greg J.; Chipman, Jeffrey G.; Schacker, Timothy W.; Silvestri, Guido

2012-01-01

Loss of the fibroblastic reticular cell (FRC) network in lymphoid tissues during HIV-1 infection has been shown to impair the survival of naive T cells and limit immune reconstitution after antiretroviral therapy. What causes this FRC loss is unknown. Because FRC loss correlates with loss of both naive CD4 and CD8 T-cell subsets and decreased lymphotoxin-β, a key factor for maintenance of FRC network, we hypothesized that loss of naive T cells is responsible for loss of the FRC network. To test this hypothesis, we assessed the consequences of antibody-mediated depletion of CD4 and CD8 T cells in rhesus macaques and sooty mangabeys. We found that only CD4 T-cell depletion resulted in FRC loss in both species and that this loss was caused by decreased lymphotoxin-β mainly produced by the CD4 T cells. We further found the same dependence of the FRC network on CD4 T cells in HIV-1–infected patients before and after antiretroviral therapy and in other immunodeficiency conditions, such as CD4 depletion in cancer patients induced by chemotherapy and irradiation. CD4 T cells thus play a central role in the maintenance of lymphoid tissue structure necessary for their own homeostasis and reconstitution. PMID:22613799

A high density field reversed configuration (FRC) target for magnetized target fusion: First internal profile measurements of a high density FRC

NASA Astrophysics Data System (ADS)

Intrator, T.; Zhang, S. Y.; Degnan, J. H.; Furno, I.; Grabowski, C.; Hsu, S. C.; Ruden, E. L.; Sanchez, P. G.; Taccetti, J. M.; Tuszewski, M.; Waganaar, W. J.; Wurden, G. A.

2004-05-01

Magnetized target fusion (MTF) is a potentially low cost path to fusion, intermediate in plasma regime between magnetic and inertial fusion energy. It requires compression of a magnetized target plasma and consequent heating to fusion relevant conditions inside a converging flux conserver. To demonstrate the physics basis for MTF, a field reversed configuration (FRC) target plasma has been chosen that will ultimately be compressed within an imploding metal liner. The required FRC will need large density, and this regime is being explored by the FRX-L (FRC-Liner) experiment. All theta pinch formed FRCs have some shock heating during formation, but FRX-L depends further on large ohmic heating from magnetic flux annihilation to heat the high density (2-5×1022m-3), plasma to a temperature of Te+Ti≈500 eV. At the field null, anomalous resistivity is typically invoked to characterize the resistive like flux dissipation process. The first resistivity estimate for a high density collisional FRC is shown here. The flux dissipation process is both a key issue for MTF and an important underlying physics question.

Overview of C-2U FRC Experimental Program and Plans for C-2W

NASA Astrophysics Data System (ADS)

Gota, H.; Binderbauer, M. W.; Tajima, T.; Putvinski, S.; Tuszewski, M.; Dettrick, S.; Korepanov, S.; Smirnov, A.; Thompson, M. C.; Yang, X.; Cappello, M.; Ivanov, A. A.; TAE Team

2016-10-01

Tri Alpha Energy's experimental program has been focused on a demonstration of reliable field-reversed configuration (FRC) formation and sustainment, driven by fast ions via high-power neutral-beam (NB) injection. The world's largest compact-toroid experimental devices, C-2 and C-2U, have successfully produced a well-stabilized, sustainable FRC plasma state with NB injection (input power, PNB 10 + MW; 15 keV hydrogen) and end-on coaxial plasma guns. Remarkable improvements in confinement and stability of FRC plasmas have led to further improved fast-ion build up; thereby, an advanced beam-driven FRC state has been produced and sustained for up to 5 + ms (longer than all characteristic system time scales), only limited by hardware and electric supply constraints such as NB and plasma-gun power supplies. To further improve the FRC performance the C-2U device is being replaced by C-2W featuring higher injected NB power, longer pulse duration as well as enhanced edge-biasing systems and substantially upgraded divertors. Main C-2U experimental results and key features of C-2W will be presented. Tri Alpha Energy, Inc.

The FAST (FRC Acceleration Space Thruster) Experiment

NASA Technical Reports Server (NTRS)

Martin, Adam; Eskridge, R.; Lee, M.; Richeson, J.; Smith, J.; Thio, Y. C. F.; Slough, J.; Rodgers, Stephen L. (Technical Monitor)

2001-01-01

The Field Reverse Configuration (FRC) is a magnetized plasmoid that has been developed for use in magnetic confinement fusion. Several of its properties suggest that it may also be useful as a thruster for in-space propulsion. The FRC is a compact toroid that has only poloidal field, and is characterized by a high plasma beta = (P)/(B (sup 2) /2Mu0), the ratio of plasma pressure to magnetic field pressure, so that it makes efficient use of magnetic field to confine a plasma. In an FRC thruster, plasmoids would be repetitively formed and accelerated to high velocity; velocities of = 250 km/s (Isp = 25,000s) have already been achieved in fusion experiments. The FRC is inductively formed and accelerated, and so is not subject to the problem of electrode erosion. As the plasmoid may be accelerated over an extended length, it can in principle be made very efficient. And the achievable jet powers should be scalable to the MW range. A 10 kW thruster experiment - FAST (FRC Acceleration Space Thruster) has just started at the Marshall Space Flight Center. The design of FAST and the status of construction and operation will be presented.

Adhesion of maxillofacial silicone elastomer to a fiber-reinforced composite resin framework.

PubMed

Kantola, Rosita; Lassila, Lippo; Vallittu, Pekka

2011-01-01

Recently, fiber-reinforced composite resin (FRC) has been introduced as a framework material for maxillofacial silicone prostheses. The purpose of this research was to study the tensile bond strength between a room temperature-polymerized maxillofacial silicone elastomer and a unidirectional FRC. Three different bonding agents were compared. Specimens were loaded in tension mode according to ISO 22401 in a universal testing device with a crosshead speed of 10 mm/min until bonding failure occurred. The influence of the surface characteristics (ground vs intact) was also studied. The highest tensile bond strength was seen with Gold Platinum Primer A-330-G, followed by Sofreliner primer. One-way analysis of variance revealed that the surface treatment of the FRC and the adhesive used had a significant effect on tensile bond strength between silicone and FRC (P < .05). Grinding enhanced adhesion, especially with Gold Platinum Primer A-330-G and Sofreliner primer. The fracture type also changed to more cohesive in nature. The FRC substructure can successfully be bonded to maxillofacial silicone elastomer by using primer containing methyl ethyl ketone and dichloromethane solvent. Bonding can be improved by roughening the FRC substrate via grinding.

Relationship Between Frequent Recreational Cannabis (Marijuana and Hashish) Use and Periodontitis in Adults in the United States: National Health and Nutrition Examination Survey 2011 to 2012.

PubMed

Shariff, Jaffer A; Ahluwalia, Kavita P; Papapanou, Panos N

2017-03-01

Recreational use of cannabis, following its legalization in some countries, poses emergent oral and periodontal health concerns. The objective of this study is to examine the relationship between frequent recreational cannabis (FRC) (marijuana and hashish) use and periodontitis prevalence among adults in the United States. Data from the National Health and Nutrition Examination Survey (NHANES) 2011 to 2012 were analyzed. Primary outcome (periodontitis) was defined using the Centers for Disease Control and Prevention/American Academy of Periodontology classification as well as continuous measurements of probing depth (PD) and clinical attachment loss (AL). Exposure of interest was self-reported cannabis use, defined as "FRC use" versus "non-FRC use." Bivariate and multivariable regression models were performed using the entire analytical sample (model 1) as well as those who had never used tobacco (never-users) (model 2). Of 1,938 participants with available cannabis use data and essential covariates, 26.8% were FRC users. Mean number of sites per participant with PD ≥4, ≥6, and ≥8 mm and AL ≥3, ≥5, and ≥8 mm was significantly higher among FRC users than among non-FRC users (mean difference in number of PD sites: 6.9, 5.6, and 5.6; P <0.05; mean difference in number of AL sites: 12.7, 7.6, and 5.6; P <0.05). Average AL was higher among FRC users than among non-FRC users (1.8 versus 1.6 mm; P = 0.004). Bivariate analysis revealed positive (harmful) association between FRC use and severe periodontitis in the entire sample (odds ratio [OR]: 1.7, 95% confidence interval [CI]: 1.3 to 2.4; P = 0.002) as well as in never-smokers (OR: 2.0, 95% CI: 1.2 to 3.5; P = 0.01). This association was retained in multivariable models adjusted for demographics (age, sex, race/ethnicity, and income level), alcohol and tobacco use, diabetes mellitus, and past periodontal treatment (model 1: adjusted OR [aOR]: 1.4, 95% CI: 1.1 to 1.9; P = 0.07; model 2: aOR: 1.9, 95% CI: 1.1 to 3.2; P = 0.03). FRC use is associated with deeper PDs, more clinical AL, and higher odds of having severe periodontitis.

Microbial Interactions with Natural Organic Matter Extracted from the Oak Ridge FRC

NASA Astrophysics Data System (ADS)

Wu, X.; Jagadamma, S.; Lancaster, A.; Adams, M. W. W.; Hazen, T.; Justice, N.; Chakraborty, R.

2015-12-01

Natural organic matter (NOM) is central to microbial food webs; however, little is known about the interplay between the physical and chemical characteristics of NOM and its turnover by microbial communities based upon biotic and abiotic parameters (e.g., biogenic precursors, redox state, bioavailability). Microbial activity changes the structures and properties that influence further bioavailability of NOM. To date, our understanding of these interactions is insufficient, and indigenous microbial activities that regulate NOM turnover are poorly resolved. It is critical to identify NOM characteristics to the structure and composition of microbial communities and to the metabolic potential of that community. Towards that end, sediment samples collected from the background area well FW305 (Oak Ridge Field Research Center, Oak Ridge, TN) were tested for NOM extraction methods that used three mild solvents, e.g., phosphate buffered saline (PBS), pyrophosphate, and MilliQ-water. MilliQ-water was finally chosen for extracting sediment samples via shaking and sonication. Groundwater from well FW301 was used as an inoculum to which the extracted NOM was added as carbon sources to feed native microbes. To identify the specific functional groups of extracted NOM that are bioavailable to indigenous microbes, several techniques, including FTIR, LC-MS, EEM, were applied to characterize the extracted NOM as well as the transformed NOM metabolites. 16S rDNA amplicon sequencing was also performed to identify the specific microbial diversity that was enriched and microbial isolates that preferentially grew with these NOM was also cultivated in the lab for future detailed studies.

Acoustic emission analysis of fiber-reinforced composite in flexural testing.

PubMed

Alander, Pasi; Lassila, Lippo V J; Tezvergil, Arzu; Vallittu, Pekka K

2004-05-01

The aim of this study was to examine the emission of acoustic signals from six commercially available fiber-reinforced composites (FRC) used in the frameworks of fixed partial dentures in material bending. FRC test specimens were made of six commercially available fiber products of polyethylene or glass and five light-curing resins. FRC test specimens were polymerized with a hand light-curing unit or with a light-curing oven. The flexural test for determination of ultimate flexural strength of test specimens (n = 6) was based on the ISO 10477 standard after the specimens were stored in air or in water for two weeks. The acoustic emission (AE) signals were monitored during three-point loading test of the test specimens using a test with increasing loading levels until the specimens fractured. Generally, stress level required for the AE activity initiation ranged from 107 MPa (Ribbond) to 579 MPa (everStick). The ultimate flexural strength of FRC specimens were higher, ranging from 132 to 764 MPa, being highest with everStick and Vectris FRC, and lowest with Ribbond FRC. ANOVA showed a statistically significant difference between the initiation of AE activity and the ultimate flexural strength according to the brand (p < 0.001) storing conditions (p < 0.001) and polymerization procedure (p < 0.001). AE activity and ultimate flexural strength correlated significantly (p < 0.010, r = 0.887). The result of this study suggested that AE activity in FRC specimens started at a 19-32% lower stress level than occurred at final fracture.

Effects of internal structure on equilibrium of field-reversed configuration plasma sustained by rotating magnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yambe, Kiyoyuki; Inomoto, Michiaki; Okada, Shigefumi

The effects of an internal structure on the equilibrium of a field-reversed configuration (FRC) plasma sustained by rotating magnetic field is investigated by using detailed electrostatic probe measurements in the FRC Injection Experiment apparatus [S. Okada, et al., Nucl. Fusion. 45, 1094 (2005)]. An internal structure installed axially on the geometrical axis, which simulates Ohmic transformer or external toroidal field coils on the FRC device, brings about substantial changes in plasma density profile. The internal structure generates steep density-gradients not only on the inner side but on the outer side of the torus. The radial electric field is observed tomore » sustain the ion thermal pressure-gradient in the FRC without the internal structure; however, the radial electric field is not sufficient to sustain the increased ion thermal pressure-gradient in the FRC with the internal structure. Spontaneously driven azimuthal ion flow will be accountable for the imbalance of the radial pressure which is modified by the internal structure.« less

CREATION OF MUSIC WITH FIBER REINFORCED CONCRETE

NASA Astrophysics Data System (ADS)

Kato, Hayato; Takeuchi, Masaki; Ogura, Naoyuki; Kitahara, Yukiko; Okamoto, Takahisa

This research focuses on the Fiber Reinforcement Concrete(FRC) and its performance on musical tones. Thepossibility of future musical instruments made of this concrete is discussed. Recently, the technical properties of FRC had been improved and the different production styles, such as unit weight of binding material and volume of fiber in the structure, hardly affects the results of the acoustics. However, the board thickness in the FRC instruments is directly related with the variety of musical tone. The FRC musical effects were compared with those produced with wood on wind instruments. The sounds were compared with those produced with woodwind instruments. The sound pressure level was affected by the material and it becomes remarkably notorious in the high frequency levels. These differences had great influence on the spectrum analysis of the tone in the wind instruments and the sensory test. The results from the sensory test show dominant performances of brightness, beauty and power in the FRC instruments compared with those made of wood.

Bone attachment to glass-fibre-reinforced composite implant with porous surface.

PubMed

Mattila, R H; Laurila, P; Rekola, J; Gunn, J; Lassila, L V J; Mäntylä, T; Aho, A J; Vallittu, P K

2009-06-01

A method has recently been developed for producing fibre-reinforced composites (FRC) with porous surfaces, intended for use as load-bearing orthopaedic implants. This study focuses on evaluation of the bone-bonding behaviour of FRC implants. Three types of cylindrical implants, i.e. FRC implants with a porous surface, solid polymethyl methacrylate (PMMA) implants and titanium (Ti) implants, were inserted in a transverse direction into the intercondular trabeculous bone area of distal femurs and proximal tibias of New Zealand White rabbits. Animals were sacrificed at 3, 6 and 12 weeks post operation, and push-out tests (n=5-6 per implant type per time point) were then carried out. At 12 weeks the shear force at the porous FRC-bone interface was significantly higher (283.3+/-55.3N) than the shear force at interfaces of solid PMMA/bone (14.4+/-11.0 N; p<0.001) and Ti/bone (130.6+/-22.2N; p=0.001). Histological observation revealed new bone growth into the porous surface structure of FRC implants. Solid PMMA and Ti implants were encapsulated mostly with fibrous connective tissue. Finite element analysis (FEA) revealed that porous FRC implants had mechanical properties which could be tailored to smooth the shear stress distribution at the bone-implant interface and reduce the stress-shielding effect.

Inhibition mechanism of compound ethanol extracts from wuweizi (fructus schisandrae chinensis) on renal interstitial fibrosis in diabetic nephropathy model mice.

PubMed

Zhang, Yanqiu; Zhang, Daning; Zhang, Mianzhi

2012-12-01

To evaluate inhibition effect and mechanism of compound ethanol extracts from Wuweizi (Fructus Schisandrae Chinensis), Chuanxiong (Rhizoma Chuanxiong) and Muli (Cocha Ostreae) (FRC) on glomerular and tubular interstitial fibrosis in streptozocin (STZ)-induced diabetic nephropathy (ND) model mice. Twenty-seven male C57BL/6 mice were divided randomly into 3 groups: nondibetic (ND), STZ-induced diabetic (D), and STZ-induced diabetic that were treated with 5 g x kg(-1) x day(-1) of FRC by oral gavage (D(FRC)), with 9 in each group. The protein expressions of E-cadherin, alpha-smooth muscle actin (alpha-SMA), Plasminogen Activator Inhibitor-1 (PAL-1) in renal tissues were investigated by Western blotting. The expressions of fibronectin (FN) and alpha-SMA were detected by immunohistochemical method. The morphological changes of renal tissues were observed under a microscope. Renal tissues in the D(FRC) group showed a lessened degree of fibrosis. Meanwhile, the expressions of FN, alpha-SMA and PAI-1 were significantly lower in the D(FRC) group than those in the D group (all P < 0.05). FRC can ameliorate the DN in the C57BL/6 mice, and its mechanism may relate to inhibition on the epithelial to mesenchymal transdifferentiation, endothelial-myofibroblast transition and PAL-1 expression.

Development of Field-Reversed Configuration Plasma Gun Formation Techniques for Magnetized Target Fusion

NASA Astrophysics Data System (ADS)

Lynn, Alan; Gilmore, Mark; Wynkoop, Tyler; Intrator, Thomas; Weber, Thomas

2012-10-01

Magnetized Target Fusion (MTF) is an innovative approach for a relatively fast and cheap path to the production of fusion energy that utilizes magnetic confinement to assist in the compression of a hot plasma to thermonuclear conditions by an external driver. Los Alamos National Laboratory (LANL) is currently pursing demonstration of the MTF concept via compression of an FRC (field-reversed configuration) plasma by a metal liner z-pinch in conjunction with the Air Force Research Laboratory in Albuquerque, NM. A key physics issue for the FRC as an MTF target lies in the initial pre-ionization (PI) stage. The PI formation process determines the amount of magnetic flux that can be trapped to form the FRC. This trapped flux plays an important role in the FRC's final equilibrium, transport, and stability properties. It also provides the route to greatest potential gains in FRC lifetime, which is essential to provide enough time to translate and compress the FRC effectively. In conjunction with LANL we plan to test and characterize a new system to improve the initial PI plasma formation. This system will use an array of plasma guns to form the initial plasma. Initial characterization of the plasma gun behavior will be presented.

The flexural properties of endodontic post materials.

PubMed

Stewardson, Dominic A; Shortall, Adrian C; Marquis, Peter M; Lumley, Philip J

2010-08-01

To measure the flexural strengths and moduli of endodontic post materials and to assess the effect on the calculated flexural properties of varying the diameter/length (D/L) ratio of three-point bend test samples. Three-point bend testing of samples of 2mm diameter metal and fiber-reinforced composite (FRC) rods was carried out and the mechanical properties calculated at support widths of 16 mm, 32 mm and 64 mm. Weibull analysis was performed on the strength data. The flexural strengths of all the FRC post materials exceeded the yield strengths of the gold and stainless steel samples; the flexural strengths of two FRC materials were comparable with the yield strength of titanium. Stainless steel recorded the highest flexural modulus while the titanium and the two carbon fiber materials exhibited similar values just exceeding that of gold. The remaining glass fiber materials were of lower modulus within the range of 41-57 GPa. Weibull modulus values for the FRC materials ranged from 16.77 to 30.09. Decreasing the L/D ratio produced a marked decrease in flexural modulus for all materials. The flexural strengths of FRC endodontic post materials as new generally exceed the yield strengths of metals from which endodontic posts are made. The high Weibull modulus values suggest good clinical reliability of FRC posts. The flexural modulus values of the tested posts were from 2-6 times (FRC) to 4-10 times (metal) that of dentin. Valid measurement of flexural properties of endodontic post materials requires that test samples have appropriate L/D ratios. Copyright 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Immediate Repair Bond Strength of Fiber-reinforced Composite after Saliva or Water Contamination.

PubMed

Bijelic-Donova, Jasmina; Flett, Andrew; Lassila, Lippo V J; Vallittu, Pekka K

2018-05-31

This in vitro study aimed to evaluate the shear bond strength (SBS) of particulate filler composite (PFC) to saliva- or water-contaminated fiber-reinforced composite (FRC). One type of FRC substrate with semi-interpenetrating polymer matrix (semi-IPN) (everStick C&B) was used in this investigation. A microhybrid PFC (Filtek Z250) substrate served as control. Freshly cured PFC and FRC substrates were first subjected to different contamination and surface cleaning treatments, then the microhybrid PFC restorative material (Filtek Z250) was built up on the substrates in 2-mm increments and light cured. Uncontaminated and saliva- or water-contaminated substrate surfaces were either left untreated or were cleaned via phosphoric acid etching or water spray accompanied with or without adhesive composite application prior applying the adherent PFC material. SBS was evaluated after thermocycling the specimens (6000 cycles, 5°C and 55°C). Three-way ANOVA showed that both the surface contamination and the surface treatment signficantly affected the bond strength (p < 0.05). Saliva contamination reduced the SBS more than did the water contamination. SBS loss after saliva contamination was 73.7% and 31.3% for PFC and FRC, respectively. After water contamination, SBS loss was 17.2% and 13.3% for PFC and FRC, respectively. The type of surface treatment was significant for PFC (p < 0.05), but not for FRC (p = 0.572). Upon contamination of freshly cured PFC or semi-IPN FRC, surfaces should be re-prepared via phosphoric acid etching, water cleaning, drying, and application of adhesive composite in order to recover optimal bond strength.

Effects of cardiac oscillations and lung volume on acinar gas mixing during apnea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mackenzie, C.F.; Skacel, M.; Barnas, G.M.

1990-05-01

We evaluated the importance of cardiogenic gas mixing in the acini of 13 dogs during 2 min of apnea. 133Xe (1-2 mCi in 4 ml of saline) was injected into an alveolar region through an occluded pulmonary artery branch, and washout was measured by gamma scintillation scanning during continued occlusion or with blood flow reinstated. The monoexponential rate constant for Xe washout (XeW) was -0.4 +/- 0.08 (SE) min-1 at functional residual capacity (FRC) with no blood flow in the injected region. It decreased by more than half at lung volumes 500 ml above and 392 ml below FRC. Withmore » intact pulmonary blood flow, XeW was -1.0 +/- 0.08 (SE) min-1 at FRC, and it increased with decreasing lung volume. However, if calculated Xe uptake by the blood was subtracted from the XeW measured with blood flow intact, resulting values at FRC and at FRC + 500 ml were not different from XeW with no blood flow. Reasonable calculation of Xe blood uptake at 392 ml below FRC was not possible because airway closure, increased shunt, and other factors affect XeW. After death, no significant XeW could be measured, which suggests that XeW caused by molecular diffusion was small. We conclude that (1) the effect of heart motion on the lung parenchyma increases acinar gas mixing during apnea, (2) this effect diminishes above or below FRC, and (3) there is probably no direct effect of pulmonary vascular pulsatility on acinar gas mixing.« less

Clinical evaluation of fiber-reinforced composite crowns in pulp-treated primary molars: 12-month results

PubMed Central

Mohammadzadeh, Zahra; Parisay, Iman; Mehrabkhani, Maryam; Madani, Azam Sadat; Mazhari, Fatemeh

2016-01-01

Objective: The aim of this study was to evaluate the clinical performance of tooth-colored fiber-reinforced composite (FRC) crowns in pulp-treated second primary mandibular teeth. Materials and Methods: This split-mouth randomized, clinical trial performed on 67 children between 3 and 6 years with two primary mandibular second molars requiring pulp treatment. After pulp therapy, the teeth were randomly assigned to stainless steel crown (SSC) or FRC crown groups. Modified United States Public Health Service criteria were used to evaluate marginal integrity, marginal discoloration, and secondary caries in FRC crowns at intervals of 3, 6, and 12 months. Retention rate and gingival health were also compared between the two groups. The data were analyzed using Friedman, Cochran, and McNemar's tests at a significance level of 0.05. Results: Intact marginal integrity in FRC crowns at 3, 6, and 12 months were 93.2%, 94.8%, and 94.2%, respectively. Marginal discoloration and secondary caries were not found at any of the FRC crowns. The retention rates of the FRC crowns were 100%, 98.3%, and 89.7% at 3, 6 and 12 months, respectively, whereas all the SSCs were found to be present and intact after 12 months (P = 0.016). There was no statistically significant difference between the two groups in gingival health. Conclusion: According to the results of this study, it seems that when esthetics is a concern, in cooperative patients with good oral hygiene, FRC crowns can be considered as a valuable procedure. PMID:28042269

Super-Alfvénic translation of a field-reversed configuration into a large-bore dielectric chamber

NASA Astrophysics Data System (ADS)

Sekiguchi, J.; Asai, T.; Takahashi, T.

2018-01-01

An experimental device to demonstrate additional heating and control methods for a field-reversed configuration (FRC) has been developed. The newly developed device, named FRC Amplification via Translation (FAT), has a field-reversed theta-pinch plasma source and a low-elongation dielectric (transparent quartz) confinement chamber with quasi-static confinement field. In the initial experiments on the FAT device, FRC translation and trapping were successfully demonstrated. Although the typical elongation of the trapped FRC in the confinement region was roughly three, no disruptive global instability, such as tilt, was observed. The FAT device increases the latitude to perform translation-related experiments, such as those concerning inductive current drive, equivalent neutral beam injection effects, and wave applications.

Space fusion energy conversion using a field reversed configuration reactor: A new technical approach for space propulsion and power

NASA Technical Reports Server (NTRS)

Schulze, Norman R.; Miley, George H.; Santarius, John F.

1991-01-01

The fusion energy conversion design approach, the Field Reversed Configuration (FRC) - when burning deuterium and helium-3, offers a new method and concept for space transportation with high energy demanding programs, like the Manned Mars Mission and planetary science outpost missions require. FRC's will increase safety, reduce costs, and enable new missions by providing a high specific power propulsion system from a high performance fusion engine system that can be optimally designed. By using spacecraft powered by FRC's the space program can fulfill High Energy Space Missions (HESM) in a manner not otherwise possible. FRC's can potentially enable the attainment of high payload mass fractions while doing so within shorter flight times.

Effect of components and surface treatments of fiber-reinforced composite posts on bond strength to composite resin.

PubMed

Asakawa, Yuya; Takahashi, Hidekazu; Kobayashi, Masahiro; Iwasaki, Naohiko

2013-10-01

The aim of this study was to clarify the effect of the components and surface treatments of fiber-reinforced composite (FRC) posts on the durable bonding to core build-up resin evaluated using the pull-out and microtensile tests. Four types of experimental FRC posts, combinations of two types of matrix resins (polymethyl methacrylate and urethane dimethacrylate) and two types of fiberglass (E-glass and zirconia-containing glass) were examined. The FRC posts were subjected to one of three surface treatments (cleaned with ethanol, dichloromethane, or sandblasting). The bond strength between the FRC posts and core build-up resin were measured using the pull-out and microtensile tests before and after thermal cycling. The bond strengths obtained by each test before and after thermal cycling were statistically analyzed by three-way ANOVA and Tukey's multiple comparisons test (p<0.05). The bond strengths except for UDMA by the pull-out test decreased after thermal cycling. Regardless the test method and thermal cycling, matrix resins, the surface treatment and their interaction were statistically significant, but fiberglass did not. Dichloromethane treatment was effective for the PMMA-based FRC posts by the pull-out test, but not by the microtensile test. Sandblasting was effective for both PMMA- and UDMA-based FRC posts, regardless of the test method. The bond strengths were influenced by the matrix resin of the FRC post and the surface treatment. The bond strengths of the pull-out test showed a similar tendency of those of the microtensile test, but the value obtained by these test were different. Copyright © 2013 Elsevier Ltd. All rights reserved.

Antioxidant and anti-inflammatory activity of a flavonoid-rich concentrate recovered from Opuntia ficus-indica juice.

PubMed

Matias, A; Nunes, S L; Poejo, J; Mecha, E; Serra, A T; Madeira, Paulo J Amorim; Bronze, M R; Duarte, C M M

2014-12-01

In this work, Opuntia ficus indica juice was explored as a potential source of natural antioxidant and anti-inflammatory ingredients towards intestinal inflammation. An adsorption separation process was used to produce a natural flavonoid-rich concentrate (FRC) from Opuntia ficus-indica juice. The FRC effect (co- or pre-incubation) on induced-oxidative stress and induced-inflammation was evaluated in human Caco-2 cells. The main constituents identified and present in the extract are flavonoids (namely isorhamnetins and their derivatives such as isorhamnetin 3-O-rhamnose-rutinoside and isorhamnetin 3-O-rutinoside) and phenolic acids (such as ferulic, piscidic and eucomic acids). Our results showed that co-incubation of FRC with the stress-inducer attenuates radicals production in a much more significant manner than pre-incubation. These results suggest that FRC compounds which cannot pass the cell membrane freely (isorhamnetin derivatives) have an ability to inhibit the formation of H2O2-induced radicals in the surrounding environment of intestinal epithelial cells. The capacity of FRC (co-incubation) for suppressing (at the extracellular level) free radicals chain initiation or propagation reaction was probably related with a more pronounced reduction in protein oxidation. A similar response was observed in the inflammatory state, where a marked decrease in IL-8 secretion and blocked degradation of IκBα was achieved for FRC co-incubation. Simultaneously, treatment with FRC significantly reduces NO and TNF-α expression and modulates apparent permeability in Caco-2 cells. In these cases, no significant differences were found between pre- and co-incubation treatments suggesting that bioavailable phenolics, such as ferulic, eucomic and piscidic acids and isorhamnetin, act at the intracellular environment.

Success, clinical performance and patient satisfaction of direct fibre-reinforced composite fixed partial dentures - a two-year clinical study.

PubMed

Malmstrom, H; Dellanzo-Savu, A; Xiao, J; Feng, C; Jabeen, A; Romero, M; Huang, J; Ren, Y; Yunker, M A

2015-12-01

To evaluate the success, clinical performance and patient satisfaction of directly placed fibre-reinforced composite (FRC) fixed partial dentures (FPDs) in 2 years. One hundred sixty-seven FRC FPDs (120 subjects) were directly fabricated to restore a single missing tooth by six Advanced Education in General Dentistry (AEGD) residents. The FRC FPDs recipients were randomised into two groups according to the fibre materials (pre-impregnated glass or polyethylene). Clinical performance was evaluated at baseline (2 weeks), 6, 12 and 24 months by two calibrated evaluators for prosthesis adaptation, colour match, marginal discoloration, surface roughness, caries and post-operative sensitivity using modified United State Public Health Service (USPHS) criteria. Prosthesis appearance, colour, chewing ability and overall satisfaction were evaluated by patients using a visual analogue scale (VAS). Kaplan-Meier estimation was used to estimate the prosthesis success. Ninety-four patients with 137 FRC FPDs returned (21·67% attrition rate for study subjects, 17·94% for FRC FPDs). Seventeen FRC FPDs failed, due to one-end (n = 4) or two-ends (n = 4) debonding or pontic fracture (n = 9). The cumulative 2-year success rate was 84·32% and survival rate was 92·7%; there were no statistically significant differences between the groups according to different missing tooth location, retention type or fibre materials (P > 0·05). Patient satisfaction regarding prosthesis appearance, col-our, chewing ability and overall satisfaction was rated high on the VAS (mean >80 mm) for all criteria at all time points. The FRC FPDs (restoring single tooth) fabricated by AEGD residents achieved acceptable success and survival rates in a 2-year follow-up. © 2015 John Wiley & Sons Ltd.

Preparation and characterisation of poly p-phenylene-2,6-benzobisoxazole fibre-reinforced resin matrix composite for endodontic post material: a preliminary study.

PubMed

Hu, Chen; Wang, Feng; Yang, Huiyong; Ai, Jun; Wang, Linlin; Jing, Dongdong; Shao, Longquan; Zhou, Xingui

2014-12-01

Currently used fibre-reinforced composite (FRC) intracanal posts possess low flexural strength which usually causes post fracture when restoring teeth with extensive loss. To improve the flexural strength of FRC, we aimed to apply a high-performance fibre, poly p-phenylene-2, 6-benzobisoxazole (PBO), to FRCs to develop a new intracanal post material. To improve the interfacial adhesion strength, the PBO fibre was treated with coupling agent (Z-6040), argon plasma, or a combination of above two methods. The effects of the surface modifications on PBO fibre were characterised by determining the single fibre tensile strength and interfacial shear strength (IFSS). The mechanical properties of PBO FRCs were characterised by flexural strength and flexural modulus. The cytotoxicity of PBO FRC was evaluated by the MTT assay. Fibres treated with a combination of Z-6040 and argon plasma possessed a significantly higher IFSS than untreated fibres. Fibre treated with the combination of Z-6040-argon-plasma FRC had the best flexural strength (531.51 ± 26.43MPa) among all treated fibre FRCs and had sufficient flexural strength and appropriate flexural moduli to be used as intracanal post material. Furthermore, an in vitro cytotoxicity assay confirmed that PBO FRCs possessed an acceptable level of cytotoxicity. In summary, our study verified the feasibility of using PBO FRC composites as new intracanal post material. Although the mechanical property of PBO FRC still has room for improvement, our study provides a new avenue for intracanal post material development in the future. To our knowledge, this is the first study to verify the feasibility of using PBO FRC composites as new intracanal post material. Our study provided a new option for intracanal post material development. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison of heliox and oxygen as washing gases for the nitrogen washout technique in preterm infants.

PubMed

Poets, C F; Rau, G A; Gappa, M; Seidenberg, J

1996-06-01

The nitrogen washout technique usually involves exposure of the patient to 100% oxygen for several minutes. This may be dangerous in preterm infants who are at risk of retinopathy of prematurity (ROP). We wanted to know whether heliox (79% He, 21% O2) can be used instead of oxygen when determining functional residual capacity (FRC). FRC measurements were made in 14 preterm infants [median (range) gestational age at birth 34 wk (27-37 wk), and at time of study 36 wk (33-40 wk)] who were breathing room air. FRC was measured using a computerized infant pulmonary function system, beginning in random order with either 100% O2 followed by heliox or vice versa. There was no systematic difference between the two methods with regard to lung volume measurements: mean (SD) FRC values, corrected for body weight, were 22.9 (7.1) mL/kg for O2 and 23.4 (7.0) mL/kg for heliox. We did not observe a systematic influence of the type of washing gas used (heliox or oxygen) on FRC in these infants. Our results suggest that the use of heliox instead of pure oxygen may be a suitable and safer alternative for FRC measurements with the nitrogen washout technique in preterm infants who are breathing low concentrations of inspired oxygen and are still at risk of ROP.

Creep and dynamic viscoelastic behavior of endodontic fiber-reinforced composite posts.

PubMed

Papadogiannis, D; Lakes, R S; Palaghias, G; Papadogiannis, Y

2009-10-01

Fiber-reinforced composite (FRC) posts have gained much interest recently and understanding of their viscoelastic properties is important as they can be used in stress-bearing posterior restorations. The aim of this study was to evaluate the creep behavior and the viscoelastic properties of four commercial FRC posts under different temperatures and different storage conditions. The FRC posts tested were Glassix, C-Post, Carbonite and Snowlight. For the creep measurements a constant load below the proportional limit of the posts was applied and the angular deformation of the specimens was recorded. The viscoelastic parameters were determined by using dynamic torsional loading under four different conditions. All materials were susceptible to creep and exhibited linear viscoelastic behavior. Residual strain was observed in all FRC posts. The viscoelastic properties were affected by the increase of temperature and water storage (p<0.001) resulting in their decline. Carbon fiber posts exhibited better performance than glass fiber posts. FRC posts exhibit permanent strains under regular masticatory stresses that can be generated in the oral cavity. Their properties are susceptible to changes in temperature, while direct contact with water also affects them deleteriously.

Results from an 8 Joule RMF-FRC Plasma Translation Experiment for Space Propulsion

NASA Astrophysics Data System (ADS)

Hill, Carrie; Uchizono, Nolan; Holmes, Michael

2017-10-01

Field-Reversed Configuration (FRC) thrusters are attractive for advanced in-space propulsion technology as their projected performance, low specific mass, and propellant flexibility offer significant benefits over state-of-the art thrusters. A benchtop experiment to evaluate FRC thruster behavior using a Rotating Magnetic Field (RMF) formation method was constructed at the Air Force Research Laboratory. This experiment generated an RMF-FRC in a conical geometry and accelerated the plasma into a field-free drift region, using 8 J of input energy. Downstream plasma probes in a time-of-flight array measured the exhaust contents of the plasma plume. Results from this diagnostic demonstrated that the ejected mass and ion exit velocities fell short of the desired specific impulse and momentum. Two high-speed cameras were installed to diagnose the gross plasma behavior from two perspectives. Results from these images are presented here. These images show that the plasma generated in the formation region for several different operating conditions was highly non-uniform and did not form a stable closed-field topology that is expected from RMF-FRC plasmas.

Field-Reversed Configuration Power Plant Critical-Issue Scoping Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santarius, J. F.; Mogahed, E. A.; Emmert, G. A.

A team from the Universities of Wisconsin, Washington, and Illinois performed an engineering scoping study of critical issues for field-reversed configuration (FRC) power plants. The key tasks for this research were (1) systems analysis for deuterium-tritium (D-T) FRC fusion power plants, and (2) conceptual design of the blanket and shield module for an FRC fusion core. For the engineering conceptual design of the fusion core, the project team focused on intermediate-term technology. For example, one decision was to use steele structure. The FRC systems analysis led to a fusion power plant with attractive features including modest size, cylindrical symmetry, goodmore » thermal efficiency (52%), relatively easy maintenance, and a high ratio of electric power to fusion core mass, indicating that it would have favorable economics.« less

Resistance training intensity and volume affect changes in rate of force development in resistance-trained men.

PubMed

Mangine, Gerald T; Hoffman, Jay R; Wang, Ran; Gonzalez, Adam M; Townsend, Jeremy R; Wells, Adam J; Jajtner, Adam R; Beyer, Kyle S; Boone, Carleigh H; Miramonti, Amelia A; LaMonica, Michael B; Fukuda, David H; Ratamess, Nicholas A; Stout, Jeffrey R

2016-12-01

To compare the effects of two different resistance training programs, high intensity (INT) and high volume (VOL), on changes in isometric force (FRC), rate of force development (RFD), and barbell velocity during dynamic strength testing. Twenty-nine resistance-trained men were randomly assigned to either the INT (n = 15, 3-5 RM, 3-min rest interval) or VOL (n = 14, 10-12 RM, 1-min rest interval) training group for 8 weeks. All participants completed a 2-week preparatory phase prior to randomization. Measures of barbell velocity, FRC, and RFD were performed before (PRE) and following (POST) the 8-week training program. Barbell velocity was determined during one-repetition maximum (1RM) testing of the squat (SQ) and bench press (BP) exercises. The isometric mid-thigh pull was used to assess FRC and RFD at specific time bands ranging from 0 to 30, 50, 90, 100, 150, 200, and 250 ms. Analysis of covariance revealed significant (p < 0.05) group differences in peak FRC, FRC at 30-200 ms, and RFD at 50-90 ms. Significant (p < 0.05) changes in INT but not VOL in peak FRC (INT: 9.2 ± 13.8 %; VOL: -4.3 ± 10.2 %), FRC at 30-200 ms (INT: 12.5-15.8 %; VOL: -1.0 to -4.3 %), and RFD at 50 ms (INT: 78.0 ± 163 %; VOL: -4.1 ± 49.6 %) were observed. A trend (p = 0.052) was observed for RFD at 90 ms (INT: 58.5 ± 115 %; VOL: -3.5 ± 40.1 %). No group differences were observed for the observed changes in barbell velocity. Results indicate that INT is more advantageous than VOL for improving FRC and RFD, while changes in barbell velocity during dynamic strength testing are similarly improved by both protocols in resistance-trained men.

Polymer matrix of fiber-reinforced composites: Changes in the semi-interpenetrating polymer network during the shelf life.

PubMed

Khan, Aftab A; Al-Kheraif, Abdulaziz A; Al-Shehri, Abdullah M; Säilynoja, Eija; Vallittu, Pekka K

2018-02-01

This laboratory study was aimed to characterize semi-interpenetrating polymer network (semi-IPN) of fiber-reinforced composite (FRC) prepregs that had been stored for up to two years before curing. Resin impregnated prepregs of everStick C&B (StickTech-GC, Turku, Finland) glass FRC were stored at 4°C for various lengths of time, i.e., two-weeks, 6-months and 2-years. Five samples from each time group were prepared with a light initiated free radical polymerization method, which were embedded to its long axis in self-curing acrylic. The nanoindentation readings on the top surface toward the core of the sample were made for five test groups, which were named as "stage 1-5". To evaluate the nanohardness and modulus of elasticity of the polymer matrix, a total of 4 slices (100µm each) were cut from stage 1 to stage 5. Differences in nanohardness values were evaluated with analysis of variance (ANOVA), and regression model was used to develop contributing effect of the material's different stages to the total variability in the nanomechanical properties. Additional chemical and thermal characterization of the polymer matrix structure of FRC was carried out. It was hypothesized that time of storage may have an influence on the semi-IPN polymer structure of the cured FRC. The two-way ANOVA test revealed that the storage time had no significant effect on the nanohardness of FRC (p = 0.374). However, a highly significant difference in nanohardness values was observed between the different stages of FRC (P<0.001). The regression coefficient suggests nanohardness increased on average by 0.039GPa for every storage group. The increased nanohardness values in the core region of 6-months and 2-years stored prepregs might be due to phase-segregation of components of semi-IPN structure of FRC prepregs before their use. This may have an influence to the surface bonding properties of the cured FRC. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of the Impact of Alveolar Nitrogen Excretion on Indices Derived from Multiple Breath Nitrogen Washout

PubMed Central

Nielsen, Niklas; Nielsen, Jorgen G.; Horsley, Alex R.

2013-01-01

Background A large body of evidence has now accumulated describing the advantages of multiple breath washout tests over conventional spirometry in cystic fibrosis (CF). Although the majority of studies have used exogenous sulphur hexafluoride (SF6) as the tracer gas this has also led to an increased interest in nitrogen washout tests, despite the differences between these methods. The impact of body nitrogen excreted across the alveoli has previously been ignored. Methods A two-compartment lung model was developed that included ventilation heterogeneity and dead space (DS) effects, but also incorporated experimental data on nitrogen excretion. The model was used to assess the impact of nitrogen excretion on washout progress and accuracy of functional residual capacity (FRC) and lung clearance index (LCI) measurements. Results Excreted nitrogen had a small effect on accuracy of FRC (1.8%) in the healthy adult model. The error in LCI calculated with true FRC was greater (6.3%), and excreted nitrogen contributed 21% of the total nitrogen concentration at the end of the washout. Increasing DS and ventilation heterogeneity both caused further increase in measurement error. LCI was increased by 6–13% in a CF child model, and excreted nitrogen increased the end of washout nitrogen concentration by 24–49%. Conclusions Excreted nitrogen appears to have complex but clinically significant effects on washout progress, particularly in the presence of abnormal gas mixing. This may explain much of the previously described differences in washout outcomes between SF6 and nitrogen. PMID:24039916

Interactions between Natural Organic Matter and Native Microbes in the Oak Ridge FRC Groundwater

NASA Astrophysics Data System (ADS)

Wu, X.; Hazen, T.; Fox, P. M.; Nico, P. S.; Li, Q.; Yang, W.; Liu, Y.; Hess, N. J.; Zhang, P.; Qin, Y.; Zhou, J.; Chakraborty, R.

2016-12-01

Natural organic matter (NOM) is central to microbial food webs; however, little is known about the interplay between the physical and chemical characteristics of the carbon in NOM and its turnover by microbial communities. Microbial activity changes NOM's structure and properties, which may further influence the bioavailability of NOM. The change of NOM may reversely affect the microbial community structure as well. To date, our understanding of these interactions is insufficient, and it is critical to identify the role of NOM to carbon turnover, structure of microbial community and to the metabolic potential of that community. In this study, we aimed to study the interactions between NOM and native microbial communities present in groundwater at a background site (FW305 well) at Oak Ridge Field Research Center, TN. The total organic carbon and inorganic carbon in FW305 deep sediment samples were 0.071% and 0.011%, respectively. Water-soluble NOM was extracted from these sediment samples, the extraction efficiencies were 3.2% for organic carbon and 1.6% for inorganic carbon. The extracted NOM was then provided as the sole carbon source to native microbes present in groundwater. Subsamples were harvested several times from these incubations during a 50-day study. 16S rRNA gene amplicon sequencing and Geochip were used to identify the changes of microbial communities and expression of functional genes during transformation of the NOM. Several advanced chemical techniques including FTICR-MS and NEXAFS were used to characterize the C pool (i.e., NOM metabolites and microbial byproducts). Preliminary data clearly showed that microbial community responded to NOM, and shifted as functional groups in NOM transformed. Further detailed metabolite and gene-based analysis to elucidate these changes is currently being conducted.

Retrospective study of combined splinting restorations in the aesthetic zone of periodontal patients

PubMed Central

Liu, X.; Zhang, Y.; Zhou, Z.; Ma, S.

2016-01-01

Aims This retrospective study evaluated the clinical performance of combining a fiber-reinforced, composite-resin (FRC) bonded splint; bridge; fiber post; and/or resin veneer for the restoration of periodontally-involved anterior teeth. Methods Sixty-three patients with periodontally-involved anterior teeth each received one of the following splinting restorations: FRC-bonded splint-bridges (SB), a combination of an FRC-bonded splint and resin veneer (SV), or FRC-bonded splints (S). Six patients with healthy periodontal teeth received orthodontic retainers with FRC-bonded splints (OS) as a control. Modified USPHS criteria were used to evaluate the effects of rehabilitation, and the periodontal pocket depth (PPD) and clinical attachment level (CAL) of the natural teeth were measured. Results All restorations resulted in good aesthetic outcomes. SV, S in combination with fiber posts and OS all resulted in 100% acceptable ratings for each category that was directly evaluated at each follow-up. The mean PPD was 3.5 ± 1.0 mm at baseline, decreased to 3.3 ± 1.0 mm after one year (p <0.05), and subsequently increased to 3.5±1.0 mm again after four years (p >0.05). These changes were similar to those in the mean CAL. Conclusion A combination of a FRC-bonded splint, bridge, fiber post and/or resin veneer for minimally invasive prosthodontic treatment in the aesthetic zone is a good choice for periodontal patients. PMID:26964599

Feeders of Free-Roaming Cats: Personal Characteristics, Feeding Practices, and Data on Cat Health and Welfare in an Urban Setting of Israel.

PubMed

Gunther, Idit; Raz, Tal; Even Zor, Yehonatan; Bachowski, Yuval; Klement, Eyal

2016-01-01

Cat feeders serve as an important source of available food for free-roaming cats (FRCs) and can play a central role in providing data on FRC distribution, welfare, and health. Data on cat feeder personalities as well as a better understanding of their feeding practices offer relevance for decision making concerning FRC population control strategies. The current study surveyed 222 FRC feeders who responded to a municipal trap-neuter-return (TNR) campaign in an Israeli central urban setting. The aim of the study was to describe their personal characteristics, feeding practices, and the FRC populations they feed. Feeders were divided into four groups according to the number of cats they claimed to feed per day (group 1: fed up to 5 cats, group 2: fed 6-10 cats, group 3: fed 11-20 cats, and group 4: fed ≥21 cats). Most feeders were women (81%), with a median age of 58 years (range 18-81). The feeders reported an overall feeding of 3337 cats in 342 different feeding locations. Feeders of group 4 comprised 15.31% (n = 34) of all feeders but fed 56% (n = 1869) of the FRC in 37.42% (n = 128) of the feeding locations. "Heavy" feeders (groups 3 and 4) reported that they traveled significantly longer distances in order to feed the cats. Commercial dry food consisted of 90% of the food they provided, with 66% of them feeding once a day, with less food per cat per day than the other feeder groups. Interestingly, "heavy" feeders were usually singles, had on average fewer siblings, a clear preference for owning cats as pets, and lived in lower income neighborhoods. According to the feeders' reports on the FRC populations they fed, 69.7% (2325/3337) cats were neutered and 11.8% (395/3337) were kittens. In addition, they reported that 1.6% (54/3337) of the cats were limping, 2% (67/3337) suffered from a systemic disease, 4% (135/3337) had skin lesions, and 3.9% (130/3337) were suffering from a chronic disability. Abundance of kittens and morbidity rate were significantly and negatively associated with neutering rate. These findings are in accordance with the suggestion that neutering may potentially improve cat welfare by reducing morbidity. Collaboration by the authorities with these heavy feeders, who represent a small number of FRC feeders and feed substantial FRC numbers, may be significant for the control and monitoring of FRC populations and their resources.

Modeling of the merging of two colliding field reversed configuration plasmoids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Guanqiong; Wang, Xiaoguang; Li, Lulu

2016-06-15

The field reversed configuration (FRC) is one of the candidate plasma targets for the magneto-inertial fusion, and a high temperature FRC can be formed by using the collision-merging technology. Although the merging process and mechanism of FRC are quite complicated, it is thinkable to build a simple model to investigate the macroscopic equilibrium parameters including the density, the temperature and the separatrix volume, which may play an important role in the collision-merging process of FRC. It is quite interesting that the estimates of the related results based on our simple model are in agreement with the simulation results of amore » two-dimensional magneto-hydrodynamic code (MFP-2D), which has being developed by our group since the last couple of years, while these results can qualitatively fit the results of C-2 experiments by Tri-alpha energy company. On the other hand, the simple model can be used to investigate how to increase the density of the merged FRC. It is found that the amplification of the density depends on the poloidal flux-increase factor and the temperature increases with the translation speed of two plasmoids.« less

Structural Applications of Fibre Reinforced Concrete in the Czech Republic

NASA Astrophysics Data System (ADS)

Kohoutková, A.; Broukalová, I.

2017-09-01

The paper presents improvement of function and performance of the precast structural members by using fibre reinforced concrete (FRC) instead of ordinary reinforced concrete and attempts to transfer innovative technologies from laboratory in academic sphere into real industrial production which is cost-effective and brings about savings of labour and material. Three examples of successful technology transfer are shown - application of FRC in an element without common rebar reinforcement, in the element with steel rebar reinforcement and SFRC pre-tensioned structural element. Benefits of FRC utilization are discussed.

Biomechanical Assessment of Restored Mandibular Molar by Endocrown in Comparison to a Glass Fiber Post-Retained Conventional Crown: 3D Finite Element Analysis.

PubMed

Helal, Mohammed Abu; Wang, Zhigang

2017-10-25

To compare equivalent and contact stresses in a mandibular molar restored by all-ceramic crowns through two methods: ceramic endocrowns and ceramic crowns supported by fiber-reinforced composite (FRC) posts and core, by using 3D finite element analysis during normal masticatory load. Three 3D models of a mandibular first molar were made and labeled as such: intact molar with no restoration (A); ceramic endocrown-restored molar (B); ceramic crown supported by FRC posts and core restored molar (C). By using 3D FE analysis with contact components, normal masticatory load was simulated. The mvM stresses in all models were calculated. Maximal mvM stresses in the ceramic of restorations, dentin, and luting cement were contrasted among models and to values of materials' strength. Contact shear and tensile stresses in the restoration/tooth interface around restorations were also calculated. The highest mvM stress levels in the enamel and dentin for the tooth restored by ceramic endocrown were lower in the crown ceramic than in tooth restored with FRC posts and all-ceramic crowns; however, in the resin adhesive cement interface it was lower for ceramic crown supported by FRC posts than the in ceramic endocrown restoration. The maximum contact shear and tensile stress values along the restoration/tooth interface of ceramic endocrowns were lower than those with ceramic crowns supported by FRC posts. Ceramic endocrown restorations presented a lower mvM stress level in dentin than the conventional ceramic crowns supported by FRC posts and core. Ceramic endocrown restorations in molars are less susceptible to damage than those with conventional ceramic crowns retained by FRC posts. Ceramic endocrowns properly cemented in molars must not be fractured or loosen during normal masticatory load. Therefore, ceramic endocrowns are advised as practicable, minimally invasive, and esthetic restorations for root canal treated mandibular molars. © 2017 by the American College of Prosthodontists.

36 CFR 1233.20 - How are disposal clearances managed for records in NARA Federal Records Centers?

Code of Federal Regulations, 2010 CFR

2010-07-01

... NARA Federal Records Centers Program Web site (http://www.archives.gov/frc/toolkit.html#disposition...) or individual NARA Federal Records Centers (http://www.archives.gov/frc/locations.html), individual...

On the residual properties of damaged FRC

NASA Astrophysics Data System (ADS)

Zerbino, R.; Torrijos, M. C.; Giaccio, G.

2017-09-01

A discussion on the residual behaviour of Fibre Reinforced Concrete (FRC) is performed based on two selected cases of concrete degradation: the exposure at High Temperatures and the development of Alkali Silica Reactions. In addition, and taking in mind that the failure mechanism in FRC is strongly related with the fibre pull-out strength, the bond strength in damaged matrices was shown concluding that the residual bond strength is less affected than the matrix strength. As the damage increases, the compressive strength and the modulus of elasticity decrease, being the modulus of elasticity the most affected. There were no significant changes produced by the incorporation of fibres on the residual behaviour when compared with previous experience on plain damage concrete. Regarding the tensile behaviour although the first peak decreases as the damage increases, even for a severely damage FRC the residual stresses remain almost unaffected.

End-on soft x ray imaging of Field-Reversed Configurations (FRCs) on the Field-Reversal-C (FRX-C)/Large Scale Modification (LSM) experiment

NASA Astrophysics Data System (ADS)

Taggart, D. P.; Gribble, R. J.; Bailey, A. D., III; Sugimoto, S.

Recently, a prototype soft x ray pinhole camera was fielded on FRX-C/LSM at Los Alamos and TRX at Spectra Technology. The soft x ray FRC images obtained using this camera stand out in high contrast to their surroundings. It was particularly useful for studying the FRC during and shortly after formation when, at certain operating conditions, flute-like structures at the edge and internal structures of the FRC were observed which other diagnostics could not resolve. Building on this early experience, a new soft x ray pinhole camera was installed on FRX-C/LSM, which permits more rapid data acquisition and briefer exposures. It will be used to continue studying FRC formation and to look for internal structure later in time which could be a signature of instability. The initial operation of this camera is summarized.

Ex vivo fracture resistance of endodontically treated maxillary central incisors restored with fiber-reinforced composite posts and experimental dentin posts

PubMed Central

Kathuria, Ambica; Kavitha, M; Khetarpal, Suchit

2011-01-01

Aim: To compare the fracture resistance of teeth restored with fiber-reinforced composite (FRC) posts and experimental dentin posts milled from human root dentin. Materials and Methods: Thirty maxillary central incisors were divided into three groups of ten each. Twenty teeth were restored with FRC posts and solid dentin posts and numbered as Groups 2 and 3 respectively while Group 1 acted as the control, without any post. The teeth were loaded at 135° angle to their long axes after core build-up and the failure loads were recorded. Results: One-way Analysis of Variance (ANOVA) and Bonferroni multiple comparisons revealed a significant difference among test groups with the control group showing the highest fracture resistance, followed by the dentin post group and lastly the FRC post group. Conclusions: Teeth restored with dentin posts exhibited better fracture resistance than those restored with FRC posts. PMID:22144812

Adiabatic model and design of a translating field reversed configuration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Intrator, T. P.; Siemon, R. E.; Sieck, P. E.

We apply an adiabatic evolution model to predict the behavior of a field reversed configuration (FRC) during decompression and translation, as well as during boundary compression. Semi-empirical scaling laws, which were developed and benchmarked primarily for collisionless FRCs, are expected to remain valid even for the collisional regime of FRX-L experiment. We use this approach to outline the design implications for FRX-L, the high density translated FRC experiment at Los Alamos National Laboratory. A conical theta coil is used to accelerate the FRC to the largest practical velocity so it can enter a mirror bounded compression region, where it mustmore » be a suitable target for a magnetized target fusion (MTF) implosion. FRX-L provides the physics basis for the integrated MTF plasma compression experiment at the Shiva-Star pulsed power facility at Kirtland Air Force Research Laboratory, where the FRC will be compressed inside a flux conserving cylindrical shell.« less

Evaluation of aquatic sediment microcosms and their use in assessing possible effects of introduced microorganisms on ecosystem parameters.

PubMed Central

Wagner-Döbler, I; Pipke, R; Timmis, K N; Dwyer, D F

1992-01-01

In this paper we describe a sediment microcosm system consisting of 20 undisturbed, layered sediment cores with overlying site water which are incubated under identical conditions of temperature, light, stirring rate of overlying water, and water exchange rate. Ecosystem parameters (nutrient level, photosynthetic potential, community structure of heterotrophic bacteria, thymidine incorporation rate, and oxygen microgradients) of the laboratory microcosms and the source ecosystem were compared and shown to be indistinguishable for the first 2 weeks. In weeks 3 and 4, small differences were detectable in the nutrient level, community structure of heterotrophic bacteria, and thymidine incorporation rate. However, the photosynthetic potential, depth profiles of heterotrophic bacterial community structure, and oxygen microgradients were maintained throughout the incubation period and did not differ between laboratory microcosms and the source ecosystem. The microcosm system described here would thus appear to be a valid model of aquatic sediments for up to 4 weeks; the actual period would depend on the sediment source and incubation temperature. The validated systems were used with Rhine river sediment to assess possible effects on ecosystem parameters of Pseudomonas sp. strain B13 FR1(pFRC20P), a genetically engineered microorganism (GEM) that had been constructed to degrade mixtures of halo- and alkylbenzoates and -phenols. The GEM survived in the surface sediment at densities of 5 x 10(4) to 5 x 10(5)/g (dry weight) for 4 weeks and degraded added chloro- and methylaromatics. The GEM did not measurably influence ecosystem parameters such as photosynthesis, densities of selected heterotrophic bacteria, thymidine incorporation rate, and oxygen microgradients. Thus, the microcosm system described here would seem to be useful for the study of the ecology of biodegradation and the fate and effect of microorganisms introduced into the environment. PMID:1599244

Characterization of porous glass fiber-reinforced composite (FRC) implant structures: porosity and mechanical properties.

PubMed

Ylä-Soininmäki, Anne; Moritz, Niko; Lassila, Lippo V J; Peltola, Matti; Aro, Hannu T; Vallittu, Pekka K

2013-12-01

The aim of this study was to characterize the microstructure and mechanical properties of porous fiber-reinforced composites (FRC). Implants made of the FRC structures are intended for cranial applications. The FRC specimens were prepared by impregnating E-glass fiber sheet with non-resorbable bifunctional bis-phenyl glycidyl dimethacrylate and triethylene glycol dimethacrylate resin matrix. Four groups of porous FRC specimens were prepared with a different amount of resin matrix. Control group contained specimens of fibers, which were bound together with sizing only. Microstructure of the specimens was analyzed using a micro computed tomography (micro-CT) based method. Mechanical properties of the specimens were measured with a tensile test. The amount of resin matrix in the specimens had an effect on the microstructure. Total porosity was 59.5 % (median) in the group with the lowest resin content and 11.2 % (median) in the group with the highest resin content. In control group, total porosity was 94.2 % (median). Correlations with resin content were obtained for all micro-CT based parameters except TbPf. The tensile strength of the composites was 21.3 MPa (median) in the group with the highest resin content and 43.4 MPa (median) in the group with the highest resin content. The tensile strength in control group was 18.9 MPa (median). There were strong correlations between the tensile strength of the specimens and most of the micro-CT based parameters. This experiment suggests that porous FRC structures may have the potential for use in implants for cranial bone reconstructions, provided further relevant in vitro and in vivo tests are performed.

A structured analysis of in vitro failure loads and failure modes of fiber, metal, and ceramic post-and-core systems.

PubMed

Fokkinga, Wietske A; Kreulen, Cees M; Vallittu, Pekka K; Creugers, Nico H J

2004-01-01

This study sought to aggregate literature data on in vitro failure loads and failure modes of prefabricated fiber-reinforced composite (FRC) post systems and to compare them to those of prefabricated metal, custom-cast, and ceramic post systems. The literature was searched using MEDLINE from 1984 to 2003 for dental articles in English. Keywords used were (post or core or buildup or dowel) and (teeth or tooth). Additional inclusion/exclusion steps were conducted, each step by two independent readers: (1) Abstracts describing post-and-core techniques to reconstruct endodontically treated teeth and their mechanical and physical characteristics were included (descriptive studies or reviews were excluded); (2) articles that included FRC post systems were selected; (3) in vitro studies, single-rooted human teeth, prefabricated FRC posts, and composite as the core material were the selection criteria; and (4) failure loads and modes were extracted from the selected papers, and failure modes were dichotomized (distinction was made between "favorable failures," defined as reparable failures, and "unfavorable failures,"defined as irreparable [root] fractures). The literature search revealed 1,984 abstracts. Included were 244, 42, and 12 articles in the first, second, and third selection steps, respectively. Custom-cast post systems showed higher failure loads than prefabricated FRC post systems, whereas ceramic showed lower failure loads. Significantly more favorable failures occurred with prefabricated FRC post systems than with prefabricated and custom-cast metal post systems. The variable "post system" had a significant effect on mean failure loads. FRC post systems more frequently showed favorable failure modes than did metal post systems.

Bonding of fibre-reinforced composite post to root canal dentin.

PubMed

Bell, Anna-Maria Le; Lassila, Lippo V J; Kangasniemi, Ilkka; Vallittu, Pekka K

2005-08-01

The aim of this study was to determine bonding properties of two types of fibre-reinforced composite (FRC) posts cemented into root canals of molars. Serrated titanium posts served as reference. Prefabricated carbon/graphite FRC posts with cross-linked polymer matrix and individually formed glass FRC posts with interpenetrating polymer network (IPN) polymer matrix were compared. The crowns of extracted third molars were removed and post space (diameter: 1.5mm) was drilled, etched and bonded. The posts were treated with dimethacrylate adhesive resin, light-polymerized and cemented with a dual-polymerizing composite resin luting cement. After thermocycling (6000x) the samples were cut into discs of thicknesses: 1, 2 and 4mm (n=12/group). Push-out force was measured by pushing the post from one end. Assessment of failure mode was made under a stereomicroscope (1, adhesive failure between post and cement; 2, cohesive failure of post-system; 3, adhesive failure between cement and dentin). The push-out force increased with increased height of dentin disc in all groups (ANOVA, p<0.001). In the 4mm thick dentin discs the individually formed glass FRC posts showed highest push-out force and the difference to that of the titanium posts was significant (ANOVA, p<0.001). The other differences were not statistically significant. None of the individually formed glass FRC posts showed adhesive failures between the post and the cement. Contrary to the other posts, there were no adhesive (post-cement) failures with the individually formed glass FRC posts, suggesting better interfacial adhesion of cement to these posts.

High-performance fiber-reinforced concrete in a bridge deck.

DOT National Transportation Integrated Search

2005-01-01

The purpose of this research was to compare the performance of high-performance fiber-reinforced concrete (FRC) with that of conventional concrete in a bridge deck. FRC is expected to increase toughness, provide enhanced residual strength, and minimi...

Multi-Scale CNT-Based Reinforcing Polymer Matrix Composites for Lightweight Structures

NASA Technical Reports Server (NTRS)

Eberly, Daniel; Ou, Runqing; Karcz, Adam; Skandan, Ganesh; Mather, Patrick; Rodriguez, Erika

2013-01-01

Reinforcing critical areas in carbon polymer matrix composites (PMCs), also known as fiber reinforced composites (FRCs), is advantageous for structural durability. Since carbon nanotubes (CNTs) have extremely high tensile strength, they can be used as a functional additive to enhance the mechanical properties of FRCs. However, CNTs are not readily dispersible in the polymer matrix, which leads to lower than theoretically predicted improvement in mechanical, thermal, and electrical properties of CNT composites. The inability to align CNTs in a polymer matrix is also a known issue. The feasibility of incorporating aligned CNTs into an FRC was demonstrated using a novel, yet commercially viable nanofiber approach, termed NRMs (nanofiber-reinforcing mats). The NRM concept of reinforcement allows for a convenient and safe means of incorporating CNTs into FRC structural components specifically where they are needed during the fabrication process. NRMs, fabricated through a novel and scalable process, were incorporated into FRC test panels using layup and vacuum bagging techniques, where alternating layers of the NRM and carbon prepreg were used to form the reinforced FRC structure. Control FRC test panel coupons were also fabricated in the same manner, but comprised of only carbon prepreg. The FRC coupons were machined to size and tested for flexural, tensile, and compression properties. This effort demonstrated that FRC structures can be fabricated using the NRM concept, with an increased average load at break during flexural testing versus that of the control. The NASA applications for the developed technologies are for lightweight structures for in-space and launch vehicles. In addition, the developed technologies would find use in NASA aerospace applications such as rockets, aircraft, aircraft/spacecraft propulsion systems, and supporting facilities. The reinforcing aspect of the technology will allow for more efficient joining of fiber composite parts, thus offering additional weight savings. More robust structures capable of withstanding micrometeoroid and space debris impacts will be possible with the enhanced mechanical properties imparted by the aligned CNTs incorporated into the fiber composite structure, as well as the potential for improved electrical and thermal properties. The materials fabrication approach developed in the present effort is a platform for customer applications where additional reinforcement is required or would be beneficial, especially in FRC structures and component parts. Depending upon the specific customer application, the NRM could be tailored to the specific matrix resin and desired property enhancement.

Spirometry, Static Lung Volumes, and Diffusing Capacity.

PubMed

Vaz Fragoso, Carlos A; Cain, Hilary C; Casaburi, Richard; Lee, Patty J; Iannone, Lynne; Leo-Summers, Linda S; Van Ness, Peter H

2017-09-01

Spirometric Z-scores from the Global Lung Initiative (GLI) rigorously account for age-related changes in lung function and are thus age-appropriate when establishing spirometric impairments, including a restrictive pattern and air-flow obstruction. However, GLI-defined spirometric impairments have not yet been evaluated regarding associations with static lung volumes (total lung capacity [TLC], functional residual capacity [FRC], and residual volume [RV]) and gas exchange (diffusing capacity). We performed a retrospective review of pulmonary function tests in subjects ≥40 y old (mean age 64.6 y), including pre-bronchodilator measures for: spirometry ( n = 2,586), static lung volumes by helium dilution with inspiratory capacity maneuver ( n = 2,586), and hemoglobin-adjusted single-breath diffusing capacity ( n = 2,508). Using multivariable linear regression, adjusted least-squares means (adj LS Means) were calculated for TLC, FRC, RV, and hemoglobin-adjusted single-breath diffusing capacity. The adj LS Means were expressed with and without height-cubed standardization and stratified by GLI-defined spirometry, including normal ( n = 1,251), restrictive pattern ( n = 663), and air-flow obstruction (mild, [ n = 128]; moderate, [ n = 150]; and severe, [ n = 394]). Relative to normal spirometry, restrictive-pattern had lower adj LS Means for TLC, FRC, RV, and hemoglobin-adjusted single-breath diffusing capacity ( P ≤ .001). Conversely, relative to normal spirometry, mild, moderate, and severe air-flow obstruction had higher adj LS Means for FRC and RV ( P < .001). However, only mild and moderate air-flow obstruction had higher adj LS Means for TLC ( P < .001), while only moderate and severe air-flow obstruction had higher adj LS Means for RV/TLC ( P < .001) and lower adj LS Means for hemoglobin-adjusted single-breath diffusing capacity ( P < .001). Notably, TLC (calculated as FRC + inspiratory capacity) was not increased in severe air-flow obstruction ( P ≥ .11) because inspiratory capacity decreased with increasing air-flow obstruction ( P < .001), thus opposing the increased FRC ( P < .001). Finally, P values were similar whether adj LS Means were height-cubed standardized. A GLI-defined spirometric restrictive pattern is strongly associated with a restrictive ventilatory defect (decreased TLC, FRC, and RV), while GLI-defined spirometric air-flow obstruction is strongly associated with hyperinflation (increased FRC) and air trapping (increased RV and RV/TLC). Both spirometric impairments were strongly associated with impaired gas exchange (decreased hemoglobin-adjusted single-breath diffusing capacity). Copyright © 2017 by Daedalus Enterprises.

Comparison of load-bearing capacity of direct resin-bonded fiber-reinforced composite FPDs with four framework designs.

PubMed

Xie, Qiufei; Lassila, Lippo V J; Vallittu, Pekka K

2007-07-01

This in vitro study was aimed to compare the fracture resistance of directly fabricated inlay-retained fiber-reinforced composite (FRC) fixed partial dentures (FPDs) with four types of framework designs. Forty-eight directly fabricated inlay retained FPDs were made of FRC and particulate resin composite (everStick/Tetric flow and Ceram). Extracted human mandibular first premolars and first molars were as abutments. The following framework designs were tested: in the Group A (control group), the framework was made of two prepregs of unidirectional glass FRC; the Group B, two prepregs in pontic portion were covered with one layer of multidirectional fiber veil FRC; the Group C, the FRC prepregs were covered in pontic portion with four short unidirectional FRC pieces along the main prepregs; in Group D, one short unidirectional FRC prepregs were placed on the main prepregs in 90 degrees angle to the main framework. After thermal cycling, FPDs of each group (n=12) were randomly divided into two subgroups (n=6). Fracture test was performed at the universal testing machine (1mm/min) where FPDs were loaded from the occlusal direction to the occlusal fossa or to the buccal cusp. Failure patterns were observed with stereomicroscope. Median and 25%/75% percentile values were calculated and nonparametric analysis was performed. Compared with three other framework designs, the FPDs in Group D showed the highest resistance when loading to the occlusal fossa, with maximum load of 2,353.8N (25%/75%: 2,155.5/2,500.0) (p=0.000, 0.000, and 0.005 for compared with Group A, B, and C). The same group showed also higher resistance when loaded to the buccal cusp (1,416.3N (1,409.2/1,480.8)) if compared to the FPDs of the Group A and Group C (p=0.044, 0.010). In general the FPDs showed higher resistant to loading at the occlusal fossa (p<0.05). This in vitro study showed that inlay-retained FRC FPD constructed with direct technique provided high fracture resistance. The framework design that provided support for the veneering composite of the pontic contributed to the highest load-bearing capacity even when loaded to the buccal cusp.

Magnetized Target Fusion Collaboration. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slough, John

Nuclear fusion has the potential to satisfy the prodigious power that the world will demand in the future, but it has yet to be harnessed as a practical energy source. The entry of fusion as a viable, competitive source of power has been stymied by the challenge of finding an economical way to provide for the confinement and heating of the plasma fuel. It is the contention here that a simpler path to fusion can be achieved by creating fusion conditions in a different regime at small scale (~ a few cm). One such program now under study, referred tomore » as Magnetized Target Fusion (MTF), is directed at obtaining fusion in this high energy density regime by rapidly compressing a compact toroidal plasmoid commonly referred to as a Field Reversed Configuration (FRC). To make fusion practical at this smaller scale, an efficient method for compressing the FRC to fusion gain conditions is required. In one variant of MTF a conducting metal shell is imploded electrically. This radially compresses and heats the FRC plasmoid to fusion conditions. The closed magnetic field in the target plasmoid suppresses the thermal transport to the confining shell, thus lowering the imploding power needed to compress the target. The undertaking described in this report was to provide a suitable target FRC, as well as a simple and robust method for inserting and stopping the FRC within the imploding liner. The FRC must also survive during the time it takes for the metal liner to compress the FRC target. The initial work at the UW was focused on developing adequate preionization and flux trapping that were found to be essential in past experiments for obtaining the density, flux and most critically, FRC lifetime required for MTF. The timescale for testing and development of such a source can be rapidly accelerated by taking advantage of a new facility funded by the Department of Energy. At this facility, two inductive plasma accelerators (IPA) were constructed and tested. Recent experiments with these IPAs have demonstrated the ability to rapidly form, accelerate and merge two hypervelocity FRCs into a compression chamber. The resultant FRC that was formed was hot (T{sub ion} ~ 400 eV), stationary, and stable with a configuration lifetime several times that necessary for the MTF liner experiments. The accelerator length was less than 1 meter, and the time from the initiation of formation to the establishment of the final equilibrium was less than 10 microseconds. With some modification, each accelerator can be made capable of producing FRCs suitable for the production of the target plasma for the MTF liner experiment. Based on the initial FRC merging/compression results, the design and methodology for an experimental realization of the target plasma for the MTF liner experiment can now be defined. The construction and testing of the key components for the formation of the target plasma at the Air Force Research Laboratory (AFRL) will be performed on the IPA experiment, now at MSNW. A high density FRC plasmoid will be formed and accelerated out of each IPA into a merging/compression chamber similar to the imploding liner at AFRL. The properties of the resultant FRC plasma (size, temperature, density, flux, lifetime) will be obtained. The process will be optimized, and a final design for implementation at AFRL will be carried out. When implemented at AFRL it is anticipated that the colliding/merging FRCs will then be compressed by the liner. In this manner it is hoped that ultimately a plasma with ion temperatures reaching the 10 keV range and fusion gain near unity can be obtained.« less

Confinement of translated field-reversed configurations

NASA Astrophysics Data System (ADS)

Tuszewski, M.; Armstrong, W. T.; Chrien, R. E.; Klingner, P. L.; McKenna, K. F.; Rej, D. J.; Sherwood, E. G.; Siemon, R. E.

1986-03-01

The confinement properties of translating field-reversed configurations (FRC) in the FRX-C/T device [Phys. Fluids 29, (1986)] are analyzed and compared to previous data without translation and to available theory. Translation dynamics do not appear to appreciably modify the FRC confinement. Some empirical scaling laws with respect to various plasma parameters are extracted from the data. These are qualitatively similar to those obtained in the TRX-1 device [Phys. Fluids 28, 888 (1985)] without translation and with a different formation method. Translation with a static gas fill offers new opportunities such as improved particle confinement or refueling of the FRC particle inventory.

Thermal insulation of a cryogenic tank for a space telescope using a pretensioned suspension of Fiber Reinforced Composite (FRC)

NASA Astrophysics Data System (ADS)

Bongers, Bernd; Haider, Otmar; Tauber, Wolfgang

1990-09-01

For the thermal insulation of cryogenic tanks in satellite applications Fiber Reinforced Composite (FRC) materials are preferable because of their low thermal conductivity and high tensile strength compared to metallic materials. At the Infrared Space Observatory (ISO) satellite the main Liquid Helium (LHe) tank is suspended by one spatial framework and eight pretensioned chain strands at each side. Frameworks and chain strands are acting as a thermal barrier and therefore made of FRC. To meet the various and, in parts contractive requirements, sophisticated design approaches are chosen for the structural parts.

Pump-probe differencing technique for cavity-enhanced, noise-canceling saturation laser spectroscopy.

PubMed

de Vine, Glenn; McClelland, David E; Gray, Malcolm B; Close, John D

2005-05-15

We present an experimental technique that permits mechanical-noise-free, cavity-enhanced frequency measurements of an atomic transition and its hyperfine structure. We employ the 532-nm frequency-doubled output from a Nd:YAG laser and an iodine vapor cell. The cell is placed in a folded ring cavity (FRC) with counterpropagating pump and probe beams. The FRC is locked with the Pound-Drever-Hall technique. Mechanical noise is rejected by differencing the pump and probe signals. In addition, this differenced error signal provides a sensitive measure of differential nonlinearity within the FRC.

An overview of development and status of fiber-reinforced composites as dental and medical biomaterials

PubMed Central

Vallittu, Pekka K.

2018-01-01

Abstract Fibr-reinforced composites (FRC) have been used successfully for decades in many fields of science and engineering applications. Benefits of FRCs relate to physical properties of FRCs and versatile production methods, which can be utilized. Conventional hand lamination of prefabricated FRC prepregs is utilized still most commonly in fabrication of dental FRC devices but CAD-CAM systems are to be come for use in certain production steps of dental constructions and medical FRC implants. Although metals, ceramics and particulate filler resin composites have successfully been used as dental and medical biomaterials for decades, devices made out of these materials do not meet all clinical requirements. Only little attention has been paid to FRCs as dental materials and majority of the research in dental field has been focusing on particulate filler resin composites and in medical biomaterial research to biodegradable polymers. This is paradoxical because FRCs can potentially resolve many of the problems related to traditional isotropic dental and medical materials. This overview reviews the rationale and status of using biostable glass FRC in applications from restorative and prosthetic dentistry to cranial surgery. The overview highlights also the critical material based factors and clinical requirement for the succesfull use of FRCs in dental reconstructions. PMID:29707613

Fragmented red blood cells automated measurement is a useful parameter to exclude schistocytes on the blood film.

PubMed

Lesesve, J-F; Asnafi, V; Braun, F; Zini, G

2012-12-01

  The diagnosis of thrombotic microangiopathies (TMA) or disorders that may mimic their features remains difficult. Mechanical hemolytic anemia with the detection of shistocytes on the blood smear is a cornerstone finding to assess the diagnosis, but microscopic evaluation of shistocytes is still problematic with wide interobserver variations. Some of the latest generation automated blood cell counters (ABCC) propose an original quantitative approach of fragmented red cells (FRC), aiming to be equivalent to the microscopic count. This parameter has been poorly evaluated.   To assess the predictive value (PV) of this test, we conducted studies comparing automated and microscopic counts of FRC/schistocytes, based on the analysis of thousands samples in four university hospitals and using the 2 ABCC currently available (Siemens ADVIA series, Sysmex XE-2100). Reference range for FRC was <0.3% for the ADVIA and <0.5% for the XE-2100. The presence of FRC below a threshold determined at 1% (ADVIA and XE-2100) had a negative PV close to 100% to exclude the presence of schistocyte on the blood smear, but in relationship with a poor PV value. Our study validated the utility of the immediately available FRC parameter on ABCC to exclude schistocytes and the diagnosis of TMA. © 2012 Blackwell Publishing Ltd.

Behavior of Concrete Panels Reinforced with Synthetic Fibers, Mild Steel, and GFRP Composites Subjected to Blasts

DOE Office of Scientific and Technical Information (OSTI.GOV)

C. P. Pantelides; T. T. Garfield; W. D. Richins

2012-03-01

The paper presents experimental data generated for calibrating finite element models to predict the performance of reinforced concrete panels with a wide range of construction details under blast loading. The specimens were 1.2 m square panels constructed using Normal Weight Concrete (NWC) or Fiber Reinforced Concrete (FRC). FRC consisted of macro-synthetic fibers dispersed in NWC. Five types of panels were tested: NWC panels with steel bars; FRC panels without additional reinforcement; FRC panels with steel bars; NWC panels with glass fiber reinforced polymer (GFRP) bars; and NWC panels reinforced with steel bars and external GFRP laminates on both faces. Eachmore » panel type was constructed with three thicknesses: 152 mm, 254 mm, and 356 mm. FRC panels with steel bars had the best performance for new construction. NWC panels reinforced with steel bars and external GFRP laminates on both faces had the best performance for strengthening or rehabilitation of existing structures. The performance of NWC panels with GFRP bars was strongly influenced by the bar spacing. The behavior of the panels is classified in terms of damage using immediate occupancy, life safety, and near collapse performance levels. Preliminary dynamic simulations are compared to the experimental results.« less

An overview of development and status of fiber-reinforced composites as dental and medical biomaterials.

PubMed

Vallittu, Pekka K

2018-01-01

Fibr-reinforced composites (FRC) have been used successfully for decades in many fields of science and engineering applications. Benefits of FRCs relate to physical properties of FRCs and versatile production methods, which can be utilized. Conventional hand lamination of prefabricated FRC prepregs is utilized still most commonly in fabrication of dental FRC devices but CAD-CAM systems are to be come for use in certain production steps of dental constructions and medical FRC implants. Although metals, ceramics and particulate filler resin composites have successfully been used as dental and medical biomaterials for decades, devices made out of these materials do not meet all clinical requirements. Only little attention has been paid to FRCs as dental materials and majority of the research in dental field has been focusing on particulate filler resin composites and in medical biomaterial research to biodegradable polymers. This is paradoxical because FRCs can potentially resolve many of the problems related to traditional isotropic dental and medical materials. This overview reviews the rationale and status of using biostable glass FRC in applications from restorative and prosthetic dentistry to cranial surgery. The overview highlights also the critical material based factors and clinical requirement for the succesfull use of FRCs in dental reconstructions.

Final Report on Development of Optimized Field-Reversed Configuration Plasma Formation Techniques for Magnetized Target Fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lynn, Alan

2013-11-01

The University of New Mexico (UNM) proposed a collaboration with Los Alamos National Laboratory (LANL) to develop and test methods for improved formation of field-reversed configuration (FRC) plasmas relevant to magnetized target fusion (MTF) energy research. MTF is an innovative approach for a relatively fast and cheap path to the production of fusion energy that utilizes magnetic confinement to assist in the compression of a hot plasma to thermonuclear conditions by an external driver. LANL is currently pursing demonstration of the MTF concept via compression of an FRC plasma by a metal liner z-pinch in conjunction with the Air Forcemore » Research Laboratory in Albuquerque, NM. A key physics issue for the FRC's ultimate success as an MTF target lies in the initial pre-ionization (PI) stage. The PI plasma sets the initial conditions from which the FRC is created. In particular, the PI formation process determines the amount of magnetic flux that can be trapped to form the FRC. A ringing theta pinch ionization (RTPI) technique, such as currently used by the FRX-L device at LANL, has the advantages of high ionization fraction, simplicity (since no additional coils are required), and does not require internal electrodes which can introduce impurities into the plasma. However RTPI has been shown to only trap 50% of the initial bias flux at best and imposes additional engineering constraints on the capacitor banks. The amount of trapped flux plays an important role in the FRC's final equilibrium, transport, and stability properties, and provides increased ohmic heating of the FRC through induced currents as the magnetic field decays. Increasing the trapped flux also provides the route to greatest potential gains in FRC lifetime, which is essential to provide enough time to translate and compress the FRC effectively. In conjunction with LANL we initially planned to develop and test a microwave break- down system to improve the initial PI plasma formation. The UNM team would design the microwave optics and oversee the fabrication and assembly of all components and assist with integration into the FRX-L machine control system. LANL would provide a preexisting 65 kW X-band microwave source and some associated waveguide hardware. Once constructed and installed, UNM would take the lead in operating the microwave breakdown system and conducting studies to optimize its use in FRC PI formation in close cooperation with the needs of the LANL MTF team. In conjunction with our LANL collaborators, we decided after starting the project to switch from a microwave plasma breakdown approach to a plasma gun technology to use for enhanced plasma formation in the FRX-L field-reversed configuration experiment at LANL. Plasma guns would be able to provide significantly higher density plasma with greater control over its distribution in time and space within the experiment. This would allow greater control and ne-tuning of the PI plasma formed in the experiment. Multiple plasma guns would be employed to fill a Pyrex glass test chamber (built at UNM) with plasma which would then be characterized and optimized for the MTF effort.« less

[FRC measurement in intensive care patients. A definition of standards].

PubMed

Wauer, H J; Lorenz, B A; Kox, W J

1998-10-01

Determination of Functional Residual Capacity (FRC) can be performed through washout methods, indicator gas dilution or bodyplethysmography. Some of these techniques have been adapted for use in intensive care patients whilst being mechanically ventilated. However, most measurement setups are bulky, cumbersome to use and their running costs are high. Hence FRC measurement has not become a routine method in intensive care although it offers considerable advantages in the management of ventilated patients such as the determination of "best PEEP", the detection of progressive alveolar collapse in the course of acute lung injury and during weaning from mechanical ventilation. Up to now most efforts to improve and simplify FRC measurement were made at the expense of accuracy. An ideal method ought to be accurate, easy to handle and cost-effective. It should supply not only FRC data but also information about intrapulmonary gas distribution and dead space. These demands can be met using modern data acquisition software. The pros and cons of all methods available for FRC measurement are discussed in view of their suitability for intensive care patients. A conventional nitrogen washout using emission spectroscopy for measurement of nitrogen concentration gives satisfying exact values for the determination of the parameters mentioned above. The measurement error can be lowered under 5% by special corrections for flow and nitrogen signal (delay and rise times, changes of gas viscosity). For flow measurement a normal pneumotachograph can be used. Using a laptop computer for data acquisition the bed-side monitor fulfills most of the demands in intensive care. It is then also possible to measure indices of intrapulmonary gas distribution such as Alveolar Mixing Efficiency and Lung Clearance Index.

The utility of absolute risk prediction using FRAX® and Garvan Fracture Risk Calculator in daily practice.

PubMed

van Geel, Tineke A C M; Eisman, John A; Geusens, Piet P; van den Bergh, Joop P W; Center, Jacqueline R; Dinant, Geert-Jan

2014-02-01

There are two commonly used fracture risk prediction tools FRAX(®) and Garvan Fracture Risk Calculator (GARVAN-FRC). The objective of this study was to investigate the utility of these tools in daily practice. A prospective population-based 5-year follow-up study was conducted in ten general practice centres in the Netherlands. For the analyses, the FRAX(®) and GARVAN-FRC 10-year absolute risks (FRAX(®) does not have 5-year risk prediction) for all fractures were used. Among 506 postmenopausal women aged ≥60 years (mean age: 67.8±5.8 years), 48 (9.5%) sustained a fracture during follow-up. Both tools, using BMD values, distinguish between women who did and did not fracture (10.2% vs. 6.8%, respectively for FRAX(®) and 32.4% vs. 39.1%, respectively for GARVAN-FRC, p<0.0001) at group level. However, only 8.9% of those who sustained a fracture had an estimated fracture risk ≥20% using FRAX(®) compared with 53.3% using GARVAN-FRC. Although both underestimated the observed fracture risk, the GARVAN-FRC performed significantly better for women who sustained a fracture (higher sensitivity) and FRAX(®) for women who did not sustain a fracture (higher specificity). Similar results were obtained using age related cut off points. The discriminant value of both models is at least as good as models used in other medical conditions; hence they can be used to communicate the fracture risk to patients. However, given differences in the estimated risks between FRAX(®) and GARVAN-FRC, the significance of the absolute risk must be related to country-specific recommended intervention thresholds to inform the patient. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Two-year survival analysis of twisted wire fixed retainer versus spiral wire and fiber-reinforced composite retainers: a preliminary explorative single-blind randomized clinical trial.

PubMed

Sobouti, Farhad; Rakhshan, Vahid; Saravi, Mahdi Gholamrezaei; Zamanian, Ali; Shariati, Mahsa

2016-03-01

Traditional retainers (both metal and fiber-reinforced composite [FRC]) have limitations, and a retainer made from more flexible ligature wires might be advantageous. We aimed to compare an experimental design with two traditional retainers. In this prospective preliminary clinical trial, 150 post-treatment patients were enrolled and randomly divided into three groups of 50 patients each to receive mandibular canine-to-canine retainers made of FRC, flexible spiral wire (FSW), and twisted wire (TW). The patients were monitored monthly. The time at which the first signs of breakage/debonding were detected was recorded. The success rates of the retainers were compared using chi-squared, Kaplan-Meier, and Cox proportional-hazard regression analyses (α = 0.05). In total, 42 patients in the FRC group, 41 in the FSW group, and 45 in the TW group completed the study. The 2-year failure rates were 35.7% in the FRC group, 26.8% in the FSW group, and 17.8% in the TW group. These rates differed insignificantly (chi-squared p = 0.167). According to the Kaplan-Meier analysis, failure occurred at 19.95 months in the FRC group, 21.37 months in the FSW group, and 22.36 months in the TW group. The differences between the survival rates in the three groups were not significant (Cox regression p = 0.146). Although the failure rate of the experimental retainer was two times lower than that of the FRC retainer, the difference was not statistically significant. The experimental TW retainer was successful, and larger studies are warranted to verify these results.

Two-year survival analysis of twisted wire fixed retainer versus spiral wire and fiber-reinforced composite retainers: a preliminary explorative single-blind randomized clinical trial

PubMed Central

Sobouti, Farhad; Rakhshan, Vahid; Saravi, Mahdi Gholamrezaei; Zamanian, Ali

2016-01-01

Objective Traditional retainers (both metal and fiber-reinforced composite [FRC]) have limitations, and a retainer made from more flexible ligature wires might be advantageous. We aimed to compare an experimental design with two traditional retainers. Methods In this prospective preliminary clinical trial, 150 post-treatment patients were enrolled and randomly divided into three groups of 50 patients each to receive mandibular canine-to-canine retainers made of FRC, flexible spiral wire (FSW), and twisted wire (TW). The patients were monitored monthly. The time at which the first signs of breakage/debonding were detected was recorded. The success rates of the retainers were compared using chi-squared, Kaplan-Meier, and Cox proportional-hazard regression analyses (α = 0.05). Results In total, 42 patients in the FRC group, 41 in the FSW group, and 45 in the TW group completed the study. The 2-year failure rates were 35.7% in the FRC group, 26.8% in the FSW group, and 17.8% in the TW group. These rates differed insignificantly (chi-squared p = 0.167). According to the Kaplan-Meier analysis, failure occurred at 19.95 months in the FRC group, 21.37 months in the FSW group, and 22.36 months in the TW group. The differences between the survival rates in the three groups were not significant (Cox regression p = 0.146). Conclusions Although the failure rate of the experimental retainer was two times lower than that of the FRC retainer, the difference was not statistically significant. The experimental TW retainer was successful, and larger studies are warranted to verify these results. PMID:27019825

Flavonoid-rich cocoa consumption affects multiple cardiovascular risk factors in a meta-analysis of short-term studies.

PubMed

Shrime, Mark G; Bauer, Scott R; McDonald, Anna C; Chowdhury, Nubaha H; Coltart, Cordelia E M; Ding, Eric L

2011-11-01

A growing body of evidence suggests that the consumption of foods rich in polyphenolic compounds, particularly cocoa, may have cardioprotective effects. No review, however, has yet examined the effect of flavonoid-rich cocoa (FRC) on all major cardiovascular risk factors or has examined potential dose-response relationships for these effects. A systematic review and meta-analysis of randomized, controlled trials was performed to evaluate the effect of FRC on cardiovascular risk factors and to assess a dose-response relationship. Inclusion and exclusion criteria as well as dependent and independent variables were determined a priori. Data were collected for: blood pressure, pulse, total cholesterol, HDL cholesterol, LDL cholesterol, TG, BMI, C-reactive protein, flow-mediated vascular dilation (FMD), fasting glucose, fasting insulin, serum isoprostane, and insulin sensitivity/resistance indices. Twenty-four papers, with 1106 participants, met the criteria for final analysis. In response to FRC consumption, systolic blood pressure decreased by 1.63 mm Hg (P = 0.033), LDL cholesterol decreased by 0.077 mmol/L (P = 0.038), and HDL cholesterol increased by 0.046 mmol/L (P = 0.037), whereas total cholesterol, TG, and C-reactive protein remained the same. Moreover, insulin resistance decreased (HOMA-IR: -0.94 points; P < 0.001), whereas FMD increased (1.53%; P < 0.001). A nonlinear dose-response relationship was found between FRC and FMD (P = 0.004), with maximum effect observed at a flavonoid dose of 500 mg/d; a similar relationship may exist with HDL cholesterol levels (P = 0.06). FRC consumption significantly improves blood pressure, insulin resistance, lipid profiles, and FMD. These short-term benefits warrant larger long-term investigations into the cardioprotective role of FRC.

Effect of ultraviolet light irradiation period on bond strengths between fiber-reinforced composite post and core build-up composite resin.

PubMed

Asakawa, Yuya; Takahashi, Hidekazu; Iwasaki, Naohiko; Kobayashi, Masahiro

2014-01-01

The aim of the present study was to characterize the effects of the ultraviolet light (UV) irradiation period on the bond strength of fiber-reinforced composite (FRC) posts to core build-up resin. Three types of FRC posts were prepared using polymethyl methacrylate, urethane dimethacrylate, and epoxy resin. The surfaces of these posts were treated using UV irradiation at a distance of 15 mm for 0 to 600 s. The pull-out bond strength was measured and analyzed with the Dunnett's comparison test (α=0.05). The bond strengths of the post surfaces without irradiation were 6.9 to 7.4 MPa; those after irradiation were 4.2 to 26.1 MPa. The bond strengths significantly increased after 15 to 120-s irradiation. UV irradiation on the FRC posts improved the bond strengths between the FRC posts and core build-up resin regardless of the type of matrix resin.

Modelling mixing within the dead space of the lung improves predictions of functional residual capacity.

PubMed

Harrison, Chris D; Phan, Phi Anh; Zhang, Cathy; Geer, Daniel; Farmery, Andrew D; Payne, Stephen J

2017-08-01

Routine estimation of functional residual capacity (FRC) in ventilated patients has been a long held goal, with many methods previously proposed, but none have been used in routine clinical practice. This paper proposes three models for determining FRC using the nitrous oxide concentration from the entire expired breath in order to improve the precision of the estimate. Of the three models proposed, a dead space with two mixing compartments provided the best results, reducing the mean limits of agreement with the FRC measured by whole body plethysmography by up to 41%. This moves away from traditional lung models, which do not account for mixing within the dead space. Compared to literature values for FRC, the results are similar to those obtained using helium dilution and better than the LUFU device (Dräger Medical, Lubeck, Germany), with significantly better limits of agreement compared to plethysmography. Copyright © 2017 Elsevier B.V. All rights reserved.

Control of ion gyroscale fluctuations via electrostatic biasing and sheared E×B flow in the C-2 field reversed configuration

NASA Astrophysics Data System (ADS)

Schmitz, L.; Ruskov, E.; Deng, B. H.; Binderbauer, M.; Tajima, T.; Gota, H.; Tuszewski, M.

2016-03-01

Control of radial particle and thermal transport is instrumental for achieving and sustaining well-confined high-β plasma in a Field-Reversed Configuration (FRC). Radial profiles of low frequency ion gyro-scale density fluctuations (0.5≤kρs≤40), consistent with drift- or drift-interchange modes, have been measured in the scrape-off layer (SOL) and core of the C-2 Field-Reversed Configuration (FRC), together with the toroidal E×B velocity. It is shown here that axial electrostatic SOL biasing controls and reduces gyro-scale density fluctuations, resulting in very low FRC core fluctuation levels. When the radial E×B flow shearing rate decreases below the turbulence decorrelation rate, fluctuation levels increase substantially, concomitantly with onset of the n=2 instability and rapid loss of diamagnetism. Low turbulence levels, improved energy/particle confinement and substantially increased FRC life times are achieved when E×B shear near the separatrix is maintained via axial SOL biasing using an annular washer gun.

Anticholinesterase activities of cold and hot aqueous extracts of F. racemosa stem bark.

PubMed

Ahmed, Faiyaz; Urooj, Asna

2010-04-01

The present study evaluated the anticholinesterase activity of cold and hot aqueous extracts of Ficus racemosa stem bark against rat brain acetylcholinesterase in vitro. Both the cold aqueous extract (FRC) and the hot aqueous extract (FRH) exhibited a dose dependent inhibition of rat brain acetylcholinesterase. FRH showed significantly higher (P

Extended magnetohydrodynamic simulations of field reversed configuration formation and sustainment with rotating magnetic field current drive

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milroy, R. D.; Kim, C. C.; Sovinec, C. R.

Three-dimensional simulations of field reversed configuration (FRC) formation and sustainment with rotating magnetic field (RMF) current drive have been performed with the NIMROD code [C. R. Sovinec et al., J. Comput. Phys. 195, 355 (2004)]. The Hall term is a zeroth order effect with strong coupling between Fourier components, and recent enhancements to the NIMROD preconditioner allow much larger time steps than was previously possible. Boundary conditions to capture the effects of a finite length RMF antenna have been added, and simulations of FRC formation from a uniform background plasma have been performed with parameters relevant to the translation, confinement,more » and sustainment-upgrade experiment at the University of Washington [H. Y. Guo, A. L. Hoffman, and R. D. Milroy, Phys. Plasmas 14, 112502 (2007)]. The effects of both even-parity and odd-parity antennas have been investigated, and there is no evidence of a disruptive instability for either antenna type. It has been found that RMF effects extend considerably beyond the ends of the antenna, and that a large n=0 B{sub t}heta can develop in the open-field line region, producing a back torque opposing the RMF.« less

PERFORMANCE OF RC AND FRC WALL PANELS REINFORCED WITH MILD STEEL AND GFRP COMPOSITES IN BLAST EVENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Timothy Garfield; William D. Richins; Thomas K. Larson

The structural integrity of reinforced concrete structures in blast events is important for critical facilities. This paper presents experimental data generated for calibrating detailed finite element models that predict the performance of reinforced concrete wall panels with a wide range of construction details under blast loading. The test specimens were 1.2 m square wall panels constructed using Normal Weight Concrete (NWC) or Fiber Reinforced Concrete (FRC). FRC consists of macro-synthetic fibers dispersed in NWC. Five types of panels were tested: NWC panels with steel bar reinforcement (Type A); FRC panels without additional reinforcement (Type B); FRC panels with steel barmore » reinforcement (Type C); NWC panels with glass fiber reinforced polymer (GFRP) bar reinforcement (Type D); and NWC panels reinforced with steel bar reinforcement and external bidirectional GFRP overlays on both faces (Type E). An additional three Type C panels were used as control specimens (CON). Each panel type was constructed with three thicknesses: 152 mm, 254 mm, and 356 mm. The panels were instrumented with strain gauges, and accelerometers; in addition, pressure sensors and high speed videos were employed during the blast events. Panel types C and E had the best performance, whereas panel type B did not perform well. Preliminary dynamic simulations show crack patterns similar to the experimental results.« less

The role of lung inflation and sodium transport in airway liquid clearance during lung aeration in newborn rabbits.

PubMed

Siew, Melissa L; Wallace, Megan J; Allison, Beth J; Kitchen, Marcus J; te Pas, Arjan B; Islam, M Sirajul; Lewis, Robert A; Fouras, Andreas; Yagi, Naoto; Uesugi, Kentaro; Hooper, Stuart B

2013-04-01

Recent phase-contrast X-ray imaging studies suggest that inspiration primarily drives lung aeration and airway liquid clearance at birth, which questions the role of adrenaline-induced activation of epithelial sodium channels (ENaCs). We hypothesized that pressures generated by inspiration have a greater role in airway liquid clearance than do ENaCs after birth. Rabbit pups (30 d of gestation) were delivered and sedated, and 0.1 ml of saline (S) or amiloride (Am; an ENaC inhibitor) was instilled into the lungs before mechanical ventilation. Two other groups (30 d of gestation) were treated similarly but were also given adrenaline (S/Ad and Am/Ad) before mechanical ventilation. Amiloride and adrenaline did not affect functional residual capacity (FRC) recruitment (P > 0.05). Amiloride increased the rate of FRC loss between inflations (Am: -5.2 ± 0.6 ml/kg/s), whereas adrenaline reduced the rate of FRC loss (S/Ad: -1.9 ± 0.3 ml/kg/s) as compared with saline-treated controls (S: -3.5 ± -0.6 ml/kg/s; P < 0.05). These data indicate that inspiration is a major determinant of airway liquid clearance and FRC development during positive pressure ventilation. Although ENaC inhibition and adrenaline administration had no detectable effect on FRC development, ENaC may help to prevent liquid from re-entering the airways during expiration.

Environmental Perturbations: Obesity

PubMed Central

Shore, Stephanie A.

2014-01-01

Obesity currently affects about one third of the U.S. population, while another one third is overweight. The importance of obesity for certain conditions such as heart disease and type 2 diabetes is well appreciated. The effects of obesity on the respiratory system have received less attention and are the subject of this chapter. Obesity alters the static mechanic properties of the respiratory system leading to a reduction in the functional residual capacity (FRC) and the expiratory reserve volume (ERV). There is substantial variability in the effects of obesity on FRC and ERV, at least some of which is related to the location, rather than the total mass of adipose tissue. Obesity also results in airflow obstruction, which is only partially attributable to breathing at low lung volume, and can also promote airway hyperresponsiveness and asthma. Hypoxemia is common is obesity, and correlates well with FRC, as well as with measures of abdominal obesity. However, obese subjects are usually eucapnic, indicating that hypoventilation is not a common cause of their hypoxemia. Instead, hypoxemia results from ventilation perfusion mismatch caused by closure of dependent airways at FRC. Many obese subjects complain of dyspnea either at rest or during exertion, and the dyspnea score also correlates with reductions in FRC and ERV. Weight reduction should be encouraged in any symptomatic obese individual, since virtually all of the respiratory complications of obesity improve with even moderate weight loss. PMID:23737172

Oblate Field-Reversed Configuration Experiments with Neutral Beam Injection

NASA Astrophysics Data System (ADS)

T., II; Gi, K.; Umezawa, T.; Inomoto, M.; Ono, Y.

2011-11-01

The effect of energetic beam ions on oblate Field-Reversed Configurations (FRCs) has been studied experimentally in the TS-4 plasma merging device. In order to examine its kinetic effects, we developed an economical pulsed Neutral Beam Injection (NBI) system by using a washer gun plasma source and finally attained the beam power of 0.6 MW (15 kV, 40 A) for its pulse length of 0.5 ms, longer than the FRC lifetime in TS-4. The Monte Carlo simulation indicates that the tangential NB ions of 15 keV are trapped between the magnetic axis and the separatrix. We found that two merging high-s (s is plasma size normalized by ion gyroradius) hydrogen spheromaks with opposite helicities relaxed into the large scale FRC with poloidal flux as high as 15 mWb under the assistance of the NBI. Without the assistance of NBI, however, they did not relax to an FRC but to another spheromak. These facts suggest some ion kinetic effects such as toroidal ion flow are essential to FRC stability. Recently, two new NB sources with acceleration voltage and current of 15 kV and 20 A were installed on the TS-4 device on the midplane for tangential injection, increasing the beam power over 1 MW. We will start the upgraded FRC experiments using the 1 MW NBI for ion flow control.

Positive and negative regulation of T cell responses by fibroblastic reticular cells within paracortical regions of lymph nodes

PubMed Central

Siegert, Stefanie; Luther, Sanjiv A.

2012-01-01

Fibroblastic reticular cells (FRC) form the structural backbone of the T cell rich zones in secondary lymphoid organs (SLO), but also actively influence the adaptive immune response. They provide a guidance path for immigrating T lymphocytes and dendritic cells (DC) and are the main local source of the cytokines CCL19, CCL21, and IL-7, all of which are thought to positively regulate T cell homeostasis and T cell interactions with DC. Recently, FRC in lymph nodes (LN) were also described to negatively regulate T cell responses in two distinct ways. During homeostasis they express and present a range of peripheral tissue antigens, thereby participating in peripheral tolerance induction of self-reactive CD8+ T cells. During acute inflammation T cells responding to foreign antigens presented on DC very quickly release pro-inflammatory cytokines such as interferon γ. These cytokines are sensed by FRC which transiently produce nitric oxide (NO) gas dampening the proliferation of neighboring T cells in a non-cognate fashion. In summary, we propose a model in which FRC engage in a bidirectional crosstalk with both DC and T cells to increase the efficiency of the T cell response. However, during an acute response, FRC limit excessive expansion and inflammatory activity of antigen-specific T cells. This negative feedback loop may help to maintain tissue integrity and function during rapid organ growth. PMID:22973278

High-Resolution Mineralogical Characterization and Biogeochemical Modeling of Uranium Reduction Pathways at the NABIR Field-Research Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

David R. Veblen; Chen Zhu; Lee Krumholz

The effectiveness and feasibility of bioremediation at the field scale cannot be fully assessed until the mechanisms of immobilization and U speciation in the solid matrix are resolved. However, characterization of the immobilized U and its valence states is extremely difficult, because microbially mediated mineral precipitates are generally nanometer (nm)-sized, poorly crystalline, or amorphous. We are developing combined field emission gun--scanning electron microscopy (FEG-SEM, at Indiana University) and FEG transmission electron microscopy (TEM, at Hopkins) to detect and isolate uranium containing phases; (1) method developments for TEM sample preparations and parallel electron energy loss spectroscopy (EELS) determination of uranium valence;more » and (2) to determine the speciation, fate, reactivity, valence states of immobilized uranium, using the state-of-the-art 300-kV, FEG-TEM. We have obtained preliminary results on contaminated sediments from Area 3 at the Oak Ridge Field Research Center (FRC). TEM results show that the sediments contain numerous minerals, including quartz, mica/clay (muscovite and/or illite), rutile, ilmenite, zircon, and an Al-Sr-Ce-Ca phosphate mineral, none of which contain uranium above the EDS detection limit. Substantial U (up to {approx}2 wt.%) is, however, clearly associated with two materials: (1) the Fe oxyhydroxide and (2) clots of a chemically complex material that is likely a mixture of several nm-scale phases. The Fe oxyhydroxide was identified as goethite from its polycrystalline SAED pattern and EDS analysis showing it to be very Fe-rich; the aggregate also displays one of several morphologies that are common for goethite. U is strongly sorbed to goethite in the FRC sediment, and the ubiquitous association with phosphorous suggests that complexes containing both U and P may play an important role in that sorption. Results from bulk analysis and SEM had previously demonstrated the association of U with Fe and thus suggested that U may be sorbed by Fe oxide or oxyhydroxide (Dr. Roh, image presented by David Watson). However, rigorous identification of the host minerals for U requires TEM results such as these involving imaging, electron diffraction, and spectroscopic analysis. An even higher concentration of U occurs in the chemically complex material noted above. These ''clots'' are high in Fe but also contain C, O, Mg, Al, Si, P, S, Cl, K, Ca, Mn, and U. This chemical complexity strongly suggests that they consist of aggregates of carbonate, silicate, phosphate, and sulfate phases, and TEM images also suggest that they may be intergrowths of numerous exceedingly small nanoparticles. EELS and EFTEM studies should be able to resolve these various components and identify precisely where the uranium is in these complex materials. From the results, it is clear that the FEG-SEM and FEG-TEM can readily detect uranium in the FRC samples. The FEG-SEM allows a wide field of view of the samples and can detect U-rich aggregates as small as 20-30 nm. The FEG-TEM can then focus on these aggregates and use SAED, EDS, EFTEM, and PEELS techniques to determine the valence states, structures, and compositional data for these aggregates. This research will provide a crucial component for a complete understanding of the efficacy of uranium bioremediation.« less

Field reversed configuration confinement enhancement through edge biasing and neutral beam injection.

PubMed

Tuszewski, M; Smirnov, A; Thompson, M C; Korepanov, S; Akhmetov, T; Ivanov, A; Voskoboynikov, R; Schmitz, L; Barnes, D; Binderbauer, M W; Brown, R; Bui, D Q; Clary, R; Conroy, K D; Deng, B H; Dettrick, S A; Douglass, J D; Garate, E; Glass, F J; Gota, H; Guo, H Y; Gupta, D; Gupta, S; Kinley, J S; Knapp, K; Longman, A; Hollins, M; Li, X L; Luo, Y; Mendoza, R; Mok, Y; Necas, A; Primavera, S; Ruskov, E; Schroeder, J H; Sevier, L; Sibley, A; Song, Y; Sun, X; Trask, E; Van Drie, A D; Walters, J K; Wyman, M D

2012-06-22

Field reversed configurations (FRCs) with high confinement are obtained in the C-2 device by combining plasma gun edge biasing and neutral beam injection. The plasma gun creates an inward radial electric field that counters the usual FRC spin-up. The n = 2 rotational instability is stabilized without applying quadrupole magnetic fields. The FRCs are nearly axisymmetric, which enables fast ion confinement. The plasma gun also produces E × B shear in the FRC edge layer, which may explain the observed improved particle transport. The FRC confinement times are improved by factors 2 to 4, and the plasma lifetimes are extended from 1 to up to 4 ms.

LOS selective fading and AN/FRC-170(V) radio hybrid computer simulation phase A report

NASA Astrophysics Data System (ADS)

Klukis, M. K.; Lyon, T. I.; Walker, R.

1981-09-01

This report documents results of the first phase of modeling, simulation and study of the dual diversity AN/FRC-170(V) radio and frequency selective fading line of sight channel. Both hybrid computer and circuit technologies were used to develop a fast, accurate and flexible simulation tool to investigate changes and proposed improvements to the design of the AN/FRC-170(V) radio. In addition to the simulation study, a remote hybrid computer terminal was provided to DCEC for interactive study of the modeled radio and channel. Simulated performance of the radio for Rayleigh, line of sight two ray channels, and additive noise are included in the report.

Effect of location of glass fiber-reinforced composite reinforcement on the flexural properties of a maxillary complete denture in vitro.

PubMed

Takahashi, Yutaka; Yoshida, Kaneyoshi; Shimizu, Hiroshi

2011-07-01

Objective. To evaluate the effect of the location of glass fiber-reinforced composite (FRC) reinforcement on the flexural load at the proportional limit (FL-PL) and the flexural deflection of a maxillary acrylic resin complete denture. Material and methods. Maxillary acrylic resin complete dentures strengthened with and without FRC reinforcement were tested. The polymerized FRC was embedded in the denture base resin in the doughy state and placed (1) under the ridge lap region, (2) in the anterior region, (3) in the middle region or (4) in the anterior and posterior regions. The FL-PL and flexural deflection value at the 100-N loading point of the reinforced maxillary denture specimens were tested. Results. All of the reinforced dentures had a higher FL-PL than the denture without reinforcement but the FL-PL values of all the dentures were not significantly different from each other. The efficiency of the FRC reinforcement compared to the unreinforced denture was 1.54-1.75 times greater. All of the reinforced dentures showed significantly lower deflection compared to the unreinforced denture, but the flexural deflections of all the dentures were not significantly different from each other. Conclusions. The location of the FRC reinforcement did not affect the fracture resistance of the maxillary acrylic resin complete denture. All of the reinforced dentures had higher FL-PL and lower flexural deflection than the denture without reinforcement.

Nuisances and welfare of free-roaming cats in urban settings and their association with cat reproduction.

PubMed

Gunther, I; Raz, T; Berke, O; Klement, E

2015-05-01

Free roaming cats (FRC) are highly abundant in cities around the world. Increasing populations of these cats might result in impairment of cat welfare and cause nuisances and public health risks. In order to study the seasonal dynamics of FRC populations and its association with events of cat welfare impairment and nuisances, we analyzed a database of FRC-associated citizens' telephone complaint events, which were registered in five cities in Israel (total human population of 1.42 million residents) during the years 2007-2011. These complaint events were classified to the following six categories: cat's carcasses, kittens, parturition, aggressive behavior toward people, invasion to human facilities, and cat injuries and distress. Overall, 87,764 complaint events associated with these categories were registered in the five cities during the study period (123.2 complaint events per 10,000 citizens per year). Length of daylight was moderately correlated with the rate of complaints on kittens in the same month (r=0.64) and parturition in the previous month (r=0.54) (P<0.001). Both kitten and parturition-related complaints showed a prominent seasonal pattern, peaking in April and May, respectively, and declining gradually until November. 'Kittens' or 'parturition' were explicitly mentioned in 38%, 39% and 19%, respectively, of the complaints regarding cat aggressiveness toward people, cat invasion to human facilities and cat injuries and distress. In most of the cities the rate of citizen complaints regarding carcasses, aggression, invasion and injuries were still significantly correlated with rate of complaints regarding kittens after omission of these joint complaints and remained significant after controlling for seasonality. These findings imply an association of cat welfare impairment and nuisances with FRC reproduction intensity. The current study revealed the high rate of nuisances and potential public health hazards related to FRC, as well as the impairment of cat welfare, which might be merely 'the tip of the iceberg' of the real welfare situation of these cats. Further studies should examine the effectiveness of FRC population control strategies for the reduction of the rate of nuisances and public health risks related to FRC, as well as for improving their welfare. Copyright © 2015 Elsevier B.V. All rights reserved.

Comprehensive integrated spirometry using raised volume passive and forced expirations and multiple-breath nitrogen washout in infants.

PubMed

Morris, Mohy G

2010-02-28

With the rapid somatic growth and development in infants, simultaneous accurate measurements of lung volume and airway function are essential. Raised volume rapid thoracoabdominal compression (RTC) is widely used to generate forced expiration from an airway opening pressure of 30 cmH(2)O (V(30)). The (dynamic) functional residual capacity (FRC(dyn)) remains the lung volume most routinely measured. The aim of this study was to develop comprehensive integrated spirometry that included all subdivisions of lung volume at V(30) or total lung capacity (TLC(30)). Measurements were performed on 17 healthy infants aged 8.6-119.7 weeks. A commercial system for multiple-breath nitrogen washout (MBNW) to measure lung volumes and a custom made system to perform RTC were used in unison. A refined automated raised volume RTC and the following two novel single maneuvers with dual volume measurements were performed from V(30) during a brief post-hyperventilation apneic pause: (1) the passive expiratory flow was integrated to produce the inspiratory capacity (IC) and the static (passive) FRC (FRC(st)) was estimated by initiating MBNW after end-passive expiration; (2) RTC was initiated late during passive expiration, flow was integrated to produce the slow vital capacity ((j)SVC) and the residual volume (RV) was measured by initiating MBNW after end-expiration while the jacket (j) was inflated. Intrasubject FRC(dyn) and FRC(st) measurements overlapped (p=0.6420) but neither did with the RV (p<0.0001). Means (95% confidence interval) of FRC(dyn), IC, FRC(st), (j)SVC, RV, forced vital capacity and tidal volume were 21.2 (19.7-22.7), 36.7 (33.0-40.4), 21.2 (19.6-22.8), 40.7 (37.2-44.2), 18.1 (16.6-19.7), 40.7 (37.1-44.2) and 10.2 (9.6-10.7)ml/kg, respectively. Static lung volumes and capacities at V(30) and variables from the best forced expiratory flow-volume curve were dependent on age, body length and weight. In conclusion, we developed a comprehensive physiologically integrated approach for in-depth investigation of lung function at V(30) in infants. Copyright 2009 Elsevier B.V. All rights reserved.

Final report on the Magnetized Target Fusion Collaboration

DOE Office of Scientific and Technical Information (OSTI.GOV)

John Slough

Nuclear fusion has the potential to satisfy the prodigious power that the world will demand in the future, but it has yet to be harnessed as a practical energy source. The entry of fusion as a viable, competitive source of power has been stymied by the challenge of finding an economical way to provide for the confinement and heating of the plasma fuel. It is the contention here that a simpler path to fusion can be achieved by creating fusion conditions in a different regime at small scale (~ a few cm). One such program now under study, referred tomore » as Magnetized Target Fusion (MTF), is directed at obtaining fusion in this high energy density regime by rapidly compressing a compact toroidal plasmoid commonly referred to as a Field Reversed Configuration (FRC). To make fusion practical at this smaller scale, an efficient method for compressing the FRC to fusion gain conditions is required. In one variant of MTF a conducting metal shell is imploded electrically. This radially compresses and heats the FRC plasmoid to fusion conditions. The closed magnetic field in the target plasmoid suppresses the thermal transport to the confining shell, thus lowering the imploding power needed to compress the target. The undertaking to be described in this proposal is to provide a suitable target FRC, as well as a simple and robust method for inserting and stopping the FRC within the imploding liner. The timescale for testing and development can be rapidly accelerated by taking advantage of a new facility funded by the Department of Energy. At this facility, two inductive plasma accelerators (IPA) were constructed and tested. Recent experiments with these IPAs have demonstrated the ability to rapidly form, accelerate and merge two hypervelocity FRCs into a compression chamber. The resultant FRC that was formed was hot (T&ion ~ 400 eV), stationary, and stable with a configuration lifetime several times that necessary for the MTF liner experiments. The accelerator length was less than 1 meter, and the time from the initiation of formation to the establishment of the final equilibrium was less than 10 microseconds. With some modification, each accelerator was made capable of producing FRCs suitable for the production of the target plasma for the MTF liner experiment. Based on the initial FRC merging/compression results, the design and methodology for an experimental realization of the target plasma for the MTF liner experiment can now be defined. A high density FRC plasmoid is to be formed and accelerated out of each IPA into a merging/compression chamber similar to the imploding liner at AFRL. The properties of the resultant FRC plasma (size, temperature, density, flux, lifetime) are obtained in the reevant regime of interest. The process still needs to be optimized, and a final design for implementation at AFRL must now be carried out. When implemented at AFRL it is anticipated that the colliding/merging FRCs will then be compressed by the liner. In this manner it is hoped that ultimately a plasma with ion temperatures reaching the 10 keV range and fusion gain near unity can be obtained.« less

Time-Resolved Emission Spectroscopy of Field Reversed Configuration Thruster

DTIC Science & Technology

2016-08-31

radiation Collection Optics to 600um fiber Source: Scharer Research Group Source: PEARL 1. Acquire Spectrum 2. Compare to Collisional‐Radiative Model ( CRM ...calibration (deuterium lamp) • Obtain Argon FRC data and use Collisional Radiative Model ( CRM ) to extract plasma properties • Apply knowledge to improve FRC

Conservative Bin-to-Bin Fractional Collisions

DTIC Science & Technology

2016-06-28

BIN FRACTIONAL COLLISIONS Robert Martin ERC INC., SPACECRAFT PROPULSION BRANCH AIR FORCE RESEARCH LABORATORY EDWARDS AIR FORCE BASE, CA USA 30th...IMPORTANCE OF COLLISION PHYSICS Important Collisions in Spacecraft Propulsion : Discharge and Breakdown in FRC Collisional Radiative Cooling/Ionization...UNLIMITED; PA #16326 3 / 18 IMPORTANCE OF COLLISION PHYSICS Important Collisions in Spacecraft Propulsion : Discharge and Breakdown in FRC Collisional

Compact toroid injection fueling in a large field-reversed configuration

NASA Astrophysics Data System (ADS)

Asai, T.; Matsumoto, T.; Roche, T.; Allfrey, I.; Gota, H.; Sekiguchi, J.; Edo, T.; Garate, E.; Takahashi, Ts.; Binderbauer, M.; Tajima, T.

2017-07-01

A repetitively driven compact toroid (CT) injector has been developed for the large field-reversed configuration (FRC) facility of the C-2/C-2U, primarily for particle refueling. A CT is formed and injected by a magnetized coaxial plasma gun (MCPG) exclusively developed for the C-2/C-2U FRC. To refuel the particles of long-lived FRCs, multiple CT injections are required. Thus, a multi-stage discharge circuit was developed for a multi-pulsed CT injection. The drive frequency of this system can be adjusted up to 1 kHz and the number of CT shots per injector is two; the system can be further upgraded for a larger number of injection pulses. The developed MCPG can achieve a supersonic ejection velocity in the range of ~100 km s-1. The key plasma parameters of electron density, electron temperature and the number of particles are ~5  ×  1021 m-3, ~30 eV and 0.5-1.0  ×  1019, respectively. In this project, single- and double-pulsed counter CT injection fueling were conducted on the C-2/C-2U facility by two CT injectors. The CT injectors were mounted 1 m apart in the vicinity of the mid-plane. To avoid disruptive perturbation on the FRC, the CT injectors were operated at the lower limit of the particle inventory. The experiments demonstrated successful refueling with a significant density build-up of 20-30% of the FRC particle inventory per single CT injection without any deleterious effects on the C-2/C-2U FRC.

Increased Lung Volume in Infants and Toddlers at High Compared to Low Altitude

PubMed Central

Llapur, Conrado J.; Martínez, Myriam R.; Caram, María Marta; Bonilla, Federico; Cabana, Celia; Yu, Zhansheng; Tepper, Robert S.

2015-01-01

Summary Children and adults residing at high altitude (HA) compared to low altitude (LA) have larger lung volumes; however, it is unknown whether this response to chronic hypoxia begins early in life. Our objective was to determine whether infants and toddlers at HA have larger lung volumes compared to infants and toddlers at LA. Oxygen saturation (SaO2), functional residual capacity (FRC), as well as serum levels of vascular endothelial growth factor (VEGF) and erythropoietin (EPO) were measured in infants and toddlers from HA (N = 50; 3,440 m) and LA (N = 35; 440 m). There were no significant differences in somatic size for HA and LA subjects; however, HA subjects had significantly lower SaO2 (88.5% vs. 96.7%; P < 0.0001). Subjects at HA had significantly greater FRC compared to subjects at LA (group mean: 209 and 157 ml; P < 0.0001), adjusting for body length. Male infants at HA had a significantly greater FRC compared to males at LA (57 ml; P-value < 0.001); however, the increase in FRC for females at HA compared to LA was not significant (20 ml; P-value = 0.101). VEGF and EPO were significantly higher for subjects at HA compared to LA with no gender differences. In summary, infants and toddlers at HA have lower oxygen saturations, higher serum levels of VEGF and EPO, and higher FRC compared to subjects at LA; however, chronic hypoxia appears to generate a more robust response in lung growth in male compared to female infants early in life. PMID:23401418

Draft Genome Sequence of Corynebacterium ulcerans FRC58, Isolated from the Bronchitic Aspiration of a Patient in France

PubMed Central

Silva, Andréia do Socorro de Sousa; Baraúna, Rafael Azevedo; de Sá, Pablo Caracciolo Gomes; das Graças, Diego Assis; Carneiro, Adriana Ribeiro; Thouvenin, Maxime; Azevedo, Vasco; Badell, Edgar; Guiso, Nicole; da Silva, Artur Luiz da Costa

2014-01-01

Corynebacterium ulcerans is a bacterial species with high importance because it causes infections in animals and, rarely, in humans. Its virulence mechanisms remain unclear. The current study describes the draft genome of C. ulcerans FRC58, which was isolated from the bronchitic aspiration of a patient in France. PMID:24407640

Separating Spike Count Correlation from Firing Rate Correlation

PubMed Central

Vinci, Giuseppe; Ventura, Valérie; Smith, Matthew A.; Kass, Robert E.

2016-01-01

Populations of cortical neurons exhibit shared fluctuations in spiking activity over time. When measured for a pair of neurons over multiple repetitions of an identical stimulus, this phenomenon emerges as correlated trial-to-trial response variability via spike count correlation (SCC). However, spike counts can be viewed as noisy versions of firing rates, which can vary from trial to trial. From this perspective, the SCC for a pair of neurons becomes a noisy version of the corresponding firing-rate correlation (FRC). Furthermore, the magnitude of the SCC is generally smaller than that of the FRC, and is likely to be less sensitive to experimental manipulation. We provide statistical methods for disambiguating time-averaged drive from within-trial noise, thereby separating FRC from SCC. We study these methods to document their reliability, and we apply them to neurons recorded in vivo from area V4, in an alert animal. We show how the various effects we describe are reflected in the data: within-trial effects are largely negligible, while attenuation due to trial-to-trial variation dominates, and frequently produces comparisons in SCC that, because of noise, do not accurately reflect those based on the underlying FRC. PMID:26942746

[Fiber-reinforced composite in fixed prosthodontics].

PubMed

Pilo, R; Abu Rass, Z; Shmidt, A

2010-07-01

Fiber reinforced composite (FRC) is composed of resin matrix and fibers filler. Common types of fibers: polyethylene, carbon and glass. Fibers can be continuous and aligned, discontinuous and aligned, discontinuous and randomly oriented. The architecture of the fibers is unidirectional, woven or braided. The two main types are: dry fibers or impregnated. Inclusion of fibers to resin composite increased its average flexural strength in 100-200 MPa. FRC can be utilized by the dentist in direct approach (splinting, temporary winged bridge) or indirect approach (laboratory made fixed partial denture). Laboratory fixed partial denture (FPD) is made from FRC substructure and Hybrid/Microfill particulate composite veneer. Main indications: interim temporary FPD or FPD in cases of questionable abutment teeth, in aesthetic cases where All Ceram FPD is not feasible. Retention is attained by adhesive cementation to minimally prepared teeth or to conventionally prepared teeth; other options are inlay-onlay bridges or hybrid bridges. Contraindications are: poor hygiene, inability to control humidity, parafunction habits, and more than two pontics. Survival rate of FRC FPD over 5 years is 75%, lower compared to porcelain fused to metal FPD which is 95%. Main reasons for failure are: fracture of framework and delamination of the veneer. Part of the failures is repairable.

Direct Measurement of Impurity Transport in a Field Reversed Configuration

NASA Astrophysics Data System (ADS)

Roche, T.; Bolte, N.; Heidbrink, W. W.; McWilliams, R.; Wessel, F.

2011-10-01

An optical tomography system has been developed and implemented in the Flux Coil Generated Field Reversed Configuration (FCG-FRC) at Tri Alpha Energy. Sixteen chords view ~ 35 % of the FRC at the mid-plane. The chords are arranged in two identical fans of eight chords each. To measure transport of an impurity species, argon, an FRC is generated using either Nitrogen or Deuterium as the primary species. A puff valve is activated prior to the shot such that the argon begins to bleed in to the vacuum chamber as the FRC is formed. The gas is puffed at the optimal location for tomographic reconstruction. Each chord is collimated to illuminate a fiber optic cable which is fed to an array of photomultiplier tubes which are fitted with neutral density and band pass filters to allow the appropriate amount of light from the emitting, singly ionized, argon at 434 . 8 nm to be measured. Using a preliminary assumption that density of argon is proportional to light intensity gathered data have been used to reconstruct density profiles. These profiles often peak near the field null. The data are being analyzed to determine diffusive and convective transport coefficients.

Numerical Study of HHFW Heating in FRC Plasmas

NASA Astrophysics Data System (ADS)

Ceccherini, Francesco; Galeotti, Laura; Brambilla, Marco; Dettrick, Sean; Yang, Xiaokang; TAE Team

2017-10-01

The TriAlpha Energy (TAE) code RF-Pisa is a Finite Larmor Radius (FLR) full wave code developed over the years to study RF heating in the Field Reversed Configuration (FRC) in both the ion and electron cyclotron regimes. The FLR approximation is perfectly adequate to address RF propagation and absorption at the fundamental and second harmonic frequencies (as in the minority heating scheme), but it is not able to describe higher order processes such as high-harmonic fast waves (HHFW). The latter ones have frequencies lying between the ion cyclotron and lower hybrid resonances and they may represent a viable path to develop an efficient method to deposit energy inside the FRC separatrix, as suggested by recent results obtained at NSTX. A significant upgrade of RF-Pisa to include HHFW has been undertaken. In particular, the so-called ``quasi local approximation'' originally proposed for toroidal geometries has been re-derived for the cylindrical geometry and a new HHFW version of RF-Pisa concurrent to the FLR version has been developed. Here we present the first results of the application of the new code to FRC equilibria and we discuss the features of the dispersion relations and the absorption processes which characterize this novel regime.

Application of trilinear softening functions based on a cohesive crack approach to the simulation of the fracture behaviour of fibre reinforced cementitious materials.

NASA Astrophysics Data System (ADS)

Enfedaque, A.; Alberti, M. G.; Gálvez, J. C.

2017-09-01

The relevance of fibre reinforced cementitious materials (FRC) has increased due to the appearance of regulations that establish the requirements needed to take into account the contribution of the fibres in the structural design. However, in order to exploit the properties of such materials it is a key aspect being able to simulate their behaviour under fracture conditions. Considering a cohesive crack approach, several authors have studied the suitability of using several softening functions. However, none of these functions can be directly applied to FRC. The present contribution analyses the suitability of multilinear softening functions in order to obtain simulation results of fracture tests of a wide variety of FRC. The implementation of multilinear softening functions has been successfully performed by means of a material user subroutine in a commercial finite element code obtaining accurate results in a wide variety of FRC. Such softening functions were capable of simulating a ductile unloading behaviour as well as a rapid unloading followed by a reloading and afterwards a slow unloading. Moreover, the implementation performed has been proven as versatile, robust and efficient from a numerical point of view.

STRUCTURE AND FUNCTION OF SUBSURFACE MICROBIAL COMMUNITIES AFFECTING RADIONUCLIDE TRANSPORT AND BIOIMMOBILIZATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joel E. Kostka; Lee Kerkhof; Kuk-Jeong Chin

2011-06-15

The objectives of this project were to: (1) isolate and characterize novel anaerobic prokaryotes from subsurface environments exposed to high levels of mixed contaminants (U(VI), nitrate, sulfate), (2) elucidate the diversity and distribution of metabolically active metal- and nitrate-reducing prokaryotes in subsurface sediments, and (3) determine the biotic and abiotic mechanisms linking electron transport processes (nitrate, Fe(III), and sulfate reduction) to radionuclide reduction and immobilization. Mechanisms of electron transport and U(VI) transformation were examined under near in situ conditions in sediment microcosms and in field investigations at the Oak Ridge Field Research Center (ORFRC), in Oak Ridge, Tennessee, where themore » subsurface is exposed to mixed contamination predominated by uranium and nitrate. A total of 20 publications (16 published or 'in press' and 4 in review), 10 invited talks, and 43 contributed seminars/ meeting presentations were completed during the past four years of the project. PI Kostka served on one proposal review panel each year for the U.S. DOE Office of Science during the four year project period. The PI leveraged funds from the state of Florida to purchase new instrumentation that aided the project. Support was also leveraged by the PI from the Joint Genome Institute in the form of two successful proposals for genome sequencing. Draft genomes are now available for two novel species isolated during our studies and 5 more genomes are in the pipeline. We effectively addressed each of the three project objectives and research highlights are provided. Task I - Isolation and characterization of novel anaerobes: (1) A wide range of pure cultures of metal-reducing bacteria, sulfate-reducing bacteria, and denitrifying bacteria (32 strains) were isolated from subsurface sediments of the Oak Ridge Field Research Center (ORFRC), where the subsurface is exposed to mixed contamination of uranium and nitrate. These isolates which are new to science all show high sequence identity to sequences retrieved from ORFRC subsurface. (2) Based on physiological and phylogenetic characterization, two new species of subsurface bacteria were described: the metal-reducer Geobacter daltonii, and the denitrifier Rhodanobacter denitrificans. (3) Strains isolated from the ORFRC show that Rhodanobacter species are well adapted to the contaminated subsurface. Strains 2APBS1 and 116-2 grow at high salt (3% NaCl), low pH (3.5) and tolerate high concentrations of nitrate (400mM) and nitrite (100mM). Strain 2APBS1 was demonstrated to grow at in situ acidic pHs down to 2.5. (4) R. denitrificans strain 2APBS1 is the first described Rhodanobacter species shown to denitrify. Nitrate is almost entirely converted to N2O, which may account for the large accumulation of N2O in the ORFRC subsurface. (5) G. daltonii, isolated from uranium- and hydrocarbon-contaminated subsurface sediments of the ORFRC, is the first organism from the subsurface clade of the genus Geobacter that is capable of growth on aromatic hydrocarbons. (6) High quality draft genome sequences and a complete eco-physiological description are completed for R. denitrificans strain 2APBS1 and G. daltonii strain FRC-32. (7) Given their demonstrated relevance to DOE remediation efforts and the availability of detailed genotypic/phenotypic characterization, Rhodanobacter denitrificans strain 2APBS1 and Geobacter daltonii strain FRC-32 represent ideal model organisms to provide a predictive understanding of subsurface microbial activity through metabolic modeling. Tasks II and III-Diversity and distribution of active anaerobes and Mechanisms linking electron transport and the fate of radionuclides: (1) Our study showed that members of genus Rhodanobacter and Geobacter are abundant and active in the uranium and nitrate contaminated subsurface. In the contaminant source zone of the Oak Ridge site, Rhodanobacter spp. are the predominant, active organisms detected (comprising 50% to 100% of rRNA detected). (2) We demonstrated for the first time that the function of microbial communities can be quantified in subsurface sediments using messenger RNA assays (molecular proxies) under in situ conditions. (3) Active Geobacteraceae were identified and phylogenetically characterized from the cDNA of messenger RNA extracted from ORFRC subsurface sediment cores. Multiple clone sequences were retrieved from G. uraniireducens, G. daltonii, and G. metallireducens. (4) Results show that Geobacter strain FRC-32 is capable of growth on benzoate, toluene and benzene as the electron donor, thereby providing evidence that this strain is physiologically distinct from other described members of the subsurface Geobacter clade. (5) Fe(III)-reducing bacteria transform structural Fe in clay minerals from their layer edges rather than from their basal surfaces.« less

High Fidelity Modeling of Field Reversed Configuration (FRC) Thrusters

DTIC Science & Technology

2016-06-01

space propulsion . This effort consists of numerical model development, physical model development, and systematic studies of the non-linear plasma...studies of the physical characteristics of Field Reversed Configuration (FRC) plasma for advanced space propulsion . This effort consists of numerical...FRCs for propulsion application. Two of the most advanced designs are based on the theta-pinch formation and the RMF formation mechanism, which

Calculating background levels for ecological risk parameters in toxic harbor sediment

USGS Publications Warehouse

Leadon, C.J.; McDonnell, T.R.; Lear, J.; Barclift, D.

2007-01-01

Establishing background levels for biological parameters is necessary in assessing the ecological risks from harbor sediment contaminated with toxic chemicals. For chemicals in sediment, the term contaminated is defined as having concentrations above background and significant human health or ecological risk levels. For biological parameters, a site could be considered contaminated if levels of the parameter are either more or less than the background level, depending on the specific parameter. Biological parameters can include tissue chemical concentrations in ecological receptors, bioassay responses, bioaccumulation levels, and benthic community metrics. Chemical parameters can include sediment concentrations of a variety of potentially toxic chemicals. Indirectly, contaminated harbor sediment can impact shellfish, fish, birds, and marine mammals, and human populations. This paper summarizes the methods used to define background levels for chemical and biological parameters from a survey of ecological risk investigations of marine harbor sediment at California Navy bases. Background levels for regional biological indices used to quantify ecological risks for benthic communities are also described. Generally, background stations are positioned in relatively clean areas exhibiting the same physical and general chemical characteristics as nearby areas with contaminated harbor sediment. The number of background stations and the number of sample replicates per background station depend on the statistical design of the sediment ecological risk investigation, developed through the data quality objective (DQO) process. Biological data from the background stations can be compared to data from a contaminated site by using minimum or maximum background levels or comparative statistics. In Navy ecological risk assessments (ERA's), calculated background levels and appropriate ecological risk screening criteria are used to identify sampling stations and sites with contaminated sediments.

Evaluation of some properties of two fiber-reinforced composite materials.

PubMed

Lassila, Lippo V J; Tezvergil, Arzu; Lahdenperä, Milla; Alander, Pasi; Shinya, Akiyoshi; Shinya, Akikazu; Vallittu, Pekka K

2005-08-01

Water sorption, flexural properties, bonding properties, and elemental composition of photopolymerizable resin-impregnated fiber-reinforced composite (FRC) materials (everStick C&B and BR-100) (FPD) were evaluated in this study. Bar-shaped specimens (2 x 2 x 25 mm) were prepared for water sorption and flexural strength testing. The specimens (n = 6) were polymerized either with a hand light-curing unit for 40 s or, additionally, in a light-curing oven for 20 min and stored in water for 30 days. Water sorption was measured during this time, followed by measurements of flexural strength and modulus. A shear bond strength test was performed to determine the bonding characteristics of polymerized FRC to composite resin luting cement (Panavia-F), (n = 15). The cement was bonded to the FRC substrate and the specimens were thermocycled 5000 times (5-55 degrees C) in water. SEM/EDS were analyzed to evaluate the elemental composition of the glass fibers and the fiber distribution in cross section. ANOVA showed significant differences in water sorption according to brand (p < 0.05). Water sorption of everStick C&B was 1.86 wt% (hand-unit polymerized) and 1.94 wt% (oven polymerized), whereas BR-100 was 1.07 wt% and 1.17 wt%, respectively. The flexural strength of everStick C&B after 30 days' water storage was 559 MPa (hand-unit polymerized) and 796 MPa (oven-polymerized); for BR-100, the values were 547 MPa and 689 MPa, respectively. Mean shear bond strength of composite resin cement to the FRC varied between 20.1 and 23.7 MPa, showing no statistical difference between the materials. SEM/EDS analysis revealed that fibers of both FRC materials consist of the same oxides (SiO2, CaO, and Al2O3) in ratios. The distribution of fibers in the cross section of specimens was more evenly distributed in everStick C&B than in BR-100. The results of this study suggest that there are some differences in the tested properties of the FRC materials.

In vitro validation of a shape-optimized fiber-reinforced dental bridge.

PubMed

Chen, YungChung; Li, Haiyan; Fok, Alex

2011-12-01

To improve its mechanical performance, structural optimization had been used in a previous study to obtain an alternative design for a 3-unit inlay-retained fiber-reinforced composite (FRC) dental bridge. In that study, an optimized layout of the FRC substructure had been proposed to minimize stresses in the veneering composite and interfacial stresses between the composite and substructure. The current work aimed to validate in vitro the improved fracture resistance of the optimized design. All samples for the 3-unit inlay-retained FRC dental bridge were made with glass-fibers (FibreKor) as the substructure, surrounded by a veneering composite (GC Gradia). Two different FRC substructure designs were prepared: a conventional (n=20) and an optimized design (n=21). The conventional design was a straight beam linking one proximal box to the other, while the optimized design was a curved beam following the lower outline of the pontic. All samples were loaded to 400N on a universal test machine (MTS 810) with a loading speed of 0.2mm/min. During loading, the force and displacement were recorded. Meanwhile, a two-channel acoustic emission (AE) system was used to monitor the development of cracks during loading. The load-displacement curves of the two groups displayed significant differences. For the conventional design, there were numerous drops in load corresponding to local damage of the sample. For the optimized design, the load curves were much smoother. Cracks were clearly visible on the surface of the conventional group only, and the directions of those cracks were perpendicular to those of the most tensile stresses. Results from the more sensitive AE measurement also showed that the optimized design had, on average, fewer cracking events: 38 versus 2969 in the conventional design. The much lower number of AE events and smoother load-displacement curves indicated that the optimized FRC bridge design had a higher fracture resistance. It is expected that the optimized design will significantly improve the clinical performance of FRC bridges. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

The bond of different post materials to a resin composite cement and a resin composite core material.

PubMed

Stewardson, D; Shortall, A; Marquis, P

2012-01-01

To investigate the bond of endodontic post materials, with and without grit blasting, to a resin composite cement and a core material using push-out bond strength tests. Fiber-reinforced composite (FRC) posts containing carbon (C) or glass (A) fiber and a steel (S) post were cemented into cylinders of polymerized restorative composite without surface treatment (as controls) and after grit blasting for 8, 16, and 32 seconds. Additional steel post samples were sputter-coated with gold before cementation to prevent chemical interaction with the cement. Cylindrical composite cores were bonded to other samples. After sectioning into discs, bond strengths were determined using push-out testing. Profilometry and electron microscopy were used to assess the effect of grit blasting on surface topography. Mean (standard deviation) bond strength values (MPa) for untreated posts to resin cement were 8.41 (2.80) for C, 9.61(1.88) for A, and 19.90 (3.61) for S. Prolonged grit blasting increased bond strength for FRC posts but produced only a minimal increase for S. After 32 seconds, mean values were 20.65 (4.91) for C, 20.41 (2.93) for A, and 22.97 (2.87) for S. Gold-coated steel samples produced the lowest bond strength value, 7.84 (1.40). Mean bond strengths for untreated posts bonded to composite cores were 6.19 (0.95) for C, 13.22 (1.61) for A, and 8.82 (1.18) for S, and after 32 seconds of grit blasting the values were 17.30 (2.02) for C, 26.47 (3.09) for A, and 20.61 (2.67) for S. FRC materials recorded higher roughness values before and after grit blasting than S. With prolonged grit blasting, roughness increased for A and C, but not for S. There was no evidence of significant bonding to untreated FRC posts, but significant bonding occurred between untreated steel posts and the resin cement. Increases in the roughness of FRC samples were material dependent and roughening significantly increased bond strength values (p<0.05). Surface roughening of the tested FRC posts is required for effective bonding.

The effect of clinically relevant thermocycling on the flexural properties of endodontic post materials.

PubMed

Stewardson, Dominic A; Shortall, Adrian C; Marquis, Peter M

2010-05-01

It is suggested that fibre-reinforced composite (FRC) posts have lower elastic moduli than metal posts and this will reduce the incidence of root fracture. However, the mechanical properties may be altered in the oral environment. The aims of this study were to determine the effect on the flexural properties of FRC and metal post materials produced by: (1) a thermocycling regime which was clinically relevant and representative of that which would occur during 1 year in the mouth and (2) storage for 1 year at body temperature. Nine FRC and two metal post material samples were sealed in polythene sleeves and thermocycled between 10 degrees C and 50 degrees C for 10,000 cycles. Additional samples were stored dry at 37 degrees C for 1 year. The flexural strength and moduli were determined by three-point bending and compared with untreated control samples. Thermocycling and storage at 37 degrees C for 1 year decreased the mean flexural modulus of all materials. This was statistically significant for 8 of 11 materials after thermocycling, and 4 of 11 materials after storage at 37 degrees C (p<0.05). Thermocycling and storage at 37 degrees C produced a non-significant increase in yield strength for both metal post materials. Thermocycling significantly increased the flexural strength of Postec while it decreased for the other FRC materials. Storage at 37 degrees C increased the flexural strength of three FRC materials (significantly for Postec) while it was decreased among the other materials. Although some of the changes noticed in flexural properties were statistically significant, it is doubtful that they are of sufficient magnitude to affect clinical performance.

Effect of ultraviolet light irradiation on bond strength of fiber post: Evaluation of surface characteristic and bonded area of fiber post with resin cement.

PubMed

Reza, Fazal; Ibrahim, Nur Sukainah

2015-01-01

Fiber post is cemented to a root canal to restore coronal tooth structure. This research aims to evaluate the effect of ultraviolet (UV) irradiation on bond strength of fiber post with resin cement. A total of 40 of the two types of fiber posts, namely, FRC Prostec (FRC) and Fiber KOR (KOR), were used for the experiment. UV irradiation was applied on top of the fiber post surface for 0, 15, 20, and 30 min. The irradiated surface of the fiber posts (n = 5) were immediately bonded with resin cement (Rely X U200) after UV irradiation. Shear bond strength (SBS) MPa was measured, and the dislodged area of post surfaces was examined with scanning electron microscopes. Changes in surface roughness (Ra) of the FRC group after UV irradiation were observed (n = 3) using atomic force microscopy. Data of SBS were statistically analyzed using one-way analysis of variance, followed by multiple comparisons (P < 0.05). SBS was significantly higher for 20 min of UV irradiation of the FRC group while significantly higher SBS was observed with 15 min of UV irradiation of the KOR group. Resin cement was more evident (cohesive failure) on the dislodged post surface of the UV treated groups compared with the control. The surface roughness of the FRC post was Ra = 175.1 nm and Ra = 929.2 nm for the control and the 20 min group, respectively. Higher surface roughness of the UV irradiated group indicated formation of mechanical retention on the fiber post surface. Evidence of cohesive failure was observed which indicated higher SBS of fiber post with the UV irradiated group.

A novel anatomical short glass fiber reinforced post in an endodontically treated premolar mechanical resistance evaluation using acoustic emission under fatigue testing.

PubMed

Wang, Hsuan-Wen; Chang, Yen-Hsiang; Lin, Chun-Li

2017-01-01

This study evaluates the fracture resistance in an endodontically treated tooth using circular fiber-reinforced composite (FRC) and innovated anatomical short glass fiber reinforced (SGFR) posts under fatigue testing, monitored using the acoustic emission (AE) technique. An anatomical SGFR fiber post with an oval shape and slot/notch design was manufactured using an injection-molding machine. Crown/core maxillary second premolar restorations were executed using the anatomical SGFR and commercial cylindrical fiber posts under fatigue test to understand the mechanical resistances. The load versus AE signals in the fracture and fatigue tests were recorded to evaluate the restored tooth failure resistance. The static fracture resistance results showed that teeth restored using the anatomical SGFR post presented higher resistance than teeth restored using the commercial FRC post. The fatigue test endurance limitation (1.2×10 6 cycles) was 207.1N for the anatomical SGFR fiber post, higher than the 185.3N found with the commercial FRC post. The average accumulated number of AE signals and corresponding micro cracks for the anatomical SGFR fiber post (153.0 hits and 2.44 cracks) were significantly lower than those for the commercial FRC post (194.7 hits and 4.78 cracks) under 40% of the static maximum resistance fatigue test load (pass 1.2×10 6 cycles). This study concluded that the anatomical SGFR fiber post with surface slot/notch design made using precise injection molding presented superior static fracture resistance and fatigue endurance limitation than those for the commercial FRC post in an endodontically treated premolar. Copyright © 2016 Elsevier Ltd. All rights reserved.

Increased lung volume in infants and toddlers at high compared to low altitude.

PubMed

Llapur, Conrado J; Martínez, Myriam R; Caram, María Marta; Bonilla, Federico; Cabana, Celia; Yu, Zhansheng; Tepper, Robert S

2013-12-01

Children and adults residing at high altitude (HA) compared to low altitude (LA) have larger lung volumes; however, it is unknown whether this response to chronic hypoxia begins early in life. Our objective was to determine whether infants and toddlers at HA have larger lung volumes compared to infants and toddlers at LA. Oxygen saturation (SaO2 ), functional residual capacity (FRC), as well as serum levels of vascular endothelial growth factor (VEGF) and erythropoietin (EPO) were measured in infants and toddlers from HA (N = 50; 3,440 m) and LA (N = 35; 440 m). There were no significant differences in somatic size for HA and LA subjects; however, HA subjects had significantly lower SaO2 (88.5% vs. 96.7%; P < 0.0001). Subjects at HA had significantly greater FRC compared to subjects at LA (group mean: 209 and 157 ml; P < 0.0001), adjusting for body length. Male infants at HA had a significantly greater FRC compared to males at LA (57 ml; P-value < 0.001); however, the increase in FRC for females at HA compared to LA was not significant (20 ml; P-value = 0.101). VEGF and EPO were significantly higher for subjects at HA compared to LA with no gender differences. In summary, infants and toddlers at HA have lower oxygen saturations, higher serum levels of VEGF and EPO, and higher FRC compared to subjects at LA; however, chronic hypoxia appears to generate a more robust response in lung growth in male compared to female infants early in life. © 2013 Wiley Periodicals, Inc.

CPAP of 4 cm H(2)O Has no short-term benefit at term in infants with BPD.

PubMed

Sandberg, Kenneth L; Hjalmarson, Ola

2012-01-01

Lung development and function is compromised at term in infants with bronchopulmonary dysplasia (BPD), characterized by reduced functional residual capacity (FRC) and impaired gas-mixing efficiency in distal airways. To determine whether continuous positive airway pressure (CPAP) improves FRC, ventilation, distal airway function, and gas exchange in spontaneously breathing infants with BPD. Twenty-one infants with BPD (median birth weight 0.72 kg (range 0.50-1.27) and median gestational age 26 weeks (range 23-28)) were studied before and after CPAP of 4 cm H(2)O was applied by a facemask system. A multiple-breath nitrogen washout method was used to assess FRC, ventilation, and gas-mixing efficiency. Moment analysis and lung clearance index was calculated from the nitrogen-decay curve for assessment of gas-mixing efficiency. Transcutaneous (Tc) PO(2)/PCO(2) was monitored during stable infant conditions before each washout test. When CPAP was raised from 0 to 4 cm H(2)O, FRC increased significantly together with a significant increase in moment ratios (M(1)/M(0) and M(2)/M(0)). Tc PO(2) decreased significantly and the breathing pattern changed, with significantly reduced respiratory rate, minute ventilation, and alveolar ventilation. There was also an increase in tidal volume and dead space. CPAP of 4 cm H(2)O applied with a facemask at term to infants with BPD did not improve ventilation, gas-mixing efficiency in distal airways, or oxygenation despite an increase in FRC. We speculate that instead of promoting recruitment of unventilated lung volumes, increasing the end-expiratory pressure in infants with BPD may lead to an overexpansion of already ventilated parts of the lung, causing further compromise of lung function. Copyright © 2012 S. Karger AG, Basel.

Effect of ultraviolet light irradiation on bond strength of fiber post: Evaluation of surface characteristic and bonded area of fiber post with resin cement

PubMed Central

Reza, Fazal; Ibrahim, Nur Sukainah

2015-01-01

Objective: Fiber post is cemented to a root canal to restore coronal tooth structure. This research aims to evaluate the effect of ultraviolet (UV) irradiation on bond strength of fiber post with resin cement. Materials and Methods: A total of 40 of the two types of fiber posts, namely, FRC Prostec (FRC) and Fiber KOR (KOR), were used for the experiment. UV irradiation was applied on top of the fiber post surface for 0, 15, 20, and 30 min. The irradiated surface of the fiber posts (n = 5) were immediately bonded with resin cement (Rely X U200) after UV irradiation. Shear bond strength (SBS) MPa was measured, and the dislodged area of post surfaces was examined with scanning electron microscopes. Changes in surface roughness (Ra) of the FRC group after UV irradiation were observed (n = 3) using atomic force microscopy. Data of SBS were statistically analyzed using one-way analysis of variance, followed by multiple comparisons (P < 0.05). Results: SBS was significantly higher for 20 min of UV irradiation of the FRC group while significantly higher SBS was observed with 15 min of UV irradiation of the KOR group. Resin cement was more evident (cohesive failure) on the dislodged post surface of the UV treated groups compared with the control. The surface roughness of the FRC post was Ra = 175.1 nm and Ra = 929.2 nm for the control and the 20 min group, respectively. Conclusions: Higher surface roughness of the UV irradiated group indicated formation of mechanical retention on the fiber post surface. Evidence of cohesive failure was observed which indicated higher SBS of fiber post with the UV irradiated group. PMID:25713488

Glass fibre-reinforced composite laced with chlorhexidine digluconate and yeast adhesion.

PubMed

Waltimo, T; Luo, G; Samaranayake, L P; Vallittu, P K

2004-02-01

The aim of this study was to lace dental glass fibre reinforced composite (FRC) prepreg with chlorhexidine digluconate and to examine the adherence of common oral fungal pathogen Candida albicans to FRC made of the prepreg. Four different test and control material groups each comprising 16 test specimens ((5.0 x 5.0 x 0.8) mm3) each were used as substrates for C. albicans adherence. A porous polymer pre-impregnated woven glass fibre prepreg was laced with solution of chlorhexidine gluconate and it was used with autopolymerized denture base polymer to fabricate FRC test specimens. Control group (Group 1) consisted of FRC test specimens stored in water. In Group 2, the test specimens were stored in 10% chlorhexidine digluconate solution for 24 h. Group 3 consisted of specimens fabricated using such fibre reinforcements which were pre-soaked in 20% chlorhexidine digluconate and dried before preparation with denture base resin, and followed by storage of the specimens in water. Group 4 was similar to Group 3 but instead of water storage the specimens were immersed in 10% chlorhexidine digluconate for 24 h. For the candidal adhesion assay the test and control specimens were incubated in standardized suspensions of four different strains of C. albicans, rinsed and prepared for light-microscopy. The mean number of adherent cells in each group was counted microscopically and analysed statistically. There were significantly (P < 0.05) more adherent C. albicans cells found in Group 1 than in the other three groups which did not differ significantly from each other. The lowest numbers of adherent cells were found in Group 3. Pretreating the porous polymer pre-impregnated glass fibre reinforcement with chlorhexidine digluconate result in reduction in the number of adherent yeast cells on the surface FRC material.

Open lung ventilation improves functional residual capacity after extubation in cardiac surgery.

PubMed

Reis Miranda, Dinis; Struijs, Ard; Koetsier, Peter; van Thiel, Robert; Schepp, Ronald; Hop, Wim; Klein, Jan; Lachmann, Burkhard; Bogers, Ad J J C; Gommers, Diederik

2005-10-01

After cardiac surgery, functional residual capacity (FRC) after extubation is reduced significantly. We hypothesized that ventilation according to the open lung concept (OLC) attenuates FRC reduction after extubation. A prospective, single-center, randomized, controlled clinical study. Cardiothoracic operating room and intensive care unit of a university hospital. Sixty-nine patients scheduled for elective coronary artery bypass graft and/or valve surgery with cardiopulmonary bypass. Before surgery, patients were randomly assigned to three groups: (1) conventional ventilation (CV); (2) OLC, started after arrival in the intensive care unit (late open lung); and (3) OLC, started directly after intubation (early open lung). In both OLC groups, recruitment maneuvers were applied until Pao2/Fio2 was >375 Torr (50 kPa). No recruitment maneuvers were applied in the CV group. FRC was measured preoperatively and 1, 3, and 5 days after extubation. Peripheral hemoglobin saturation (Spo2) was measured daily till the third day after extubation while the patient was breathing room air. Hypoxemia was defined by an Spo2 value < or =90%. Averaged over the 5 postoperative days, FRC was significantly higher in the early open lung group and tended to be higher in the late open lung group, in comparison with the CV group (mean +/- sem: CV, 1.8 +/- 0.1; late open lung,1.9 +/- 0.1; and early open lung, 2.2 +/- 0.1l). In the CV group, 37% of the patients were hypoxic on the third day after extubation, compared with none of the patients in both OLC groups. After cardiac surgery, earlier application of OLC resulted in a significantly higher FRC and fewer episodes of hypoxemia than with CV after extubation.

Comparison of four software packages for CT lung volumetry in healthy individuals.

PubMed

Nemec, Stefan F; Molinari, Francesco; Dufresne, Valerie; Gosset, Natacha; Silva, Mario; Bankier, Alexander A

2015-06-01

To compare CT lung volumetry (CTLV) measurements provided by different software packages, and to provide normative data for lung densitometric measurements in healthy individuals. This retrospective study included 51 chest CTs of 17 volunteers (eight men and nine women; mean age, 30 ± 6 years), who underwent spirometrically monitored CT at total lung capacity (TLC), functional residual capacity (FRC), and mean inspiratory capacity (MIC). Volumetric differences assessed by four commercial software packages were compared with analysis of variance (ANOVA) for repeated measurements and benchmarked against the threshold for acceptable variability between spirometric measurements. Mean lung density (MLD) and parenchymal heterogeneity (MLD-SD) were also compared with ANOVA. Volumetric differences ranged from 12 to 213 ml (0.20 % to 6.45 %). Although 16/18 comparisons (among four software packages at TLC, MIC, and FRC) were statistically significant (P < 0.001 to P = 0.004), only 3/18 comparisons, one at MIC and two at FRC, exceeded the spirometry variability threshold. MLD and MLD-SD significantly increased with decreasing volumes, and were significantly larger in lower compared to upper lobes (P < 0.001). Lung volumetric differences provided by different software packages are small. These differences should not be interpreted based on statistical significance alone, but together with absolute volumetric differences. • Volumetric differences, assessed by different CTLV software, are small but statistically significant. • Volumetric differences are smaller at TLC than at MIC and FRC. • Volumetric differences rarely exceed spirometric repeatability thresholds at MIC and FRC. • Differences between CTLV measurements should be interpreted based on comparison of absolute differences. • MLD increases with decreasing volumes, and is larger in lower compared to upper lobes.

Influence of retainer design on two-unit cantilever resin-bonded glass fiber reinforced composite fixed dental prostheses: an in vitro and finite element analysis study.

PubMed

Keulemans, Filip; De Jager, Niek; Kleverlaan, Cornelis J; Feilzer, Albert J

2008-10-01

The aim of this study was to evaluate in vitro the influence of retainer design on the strength of two-unit cantilever resin-bonded glass fiber-reinforced composite (FRC) fixed dental prostheses (FDP). Four retainer designs were tested: a proximal box, a step-box, a dual wing, and a step-box-wing. Of each design on 8 human mandibular molars, FRC-FDPs of a premolar size were produced. The FRC framework was made of resin impregnated unidirectional glass fibers (Estenia C&B EG Fiber, Kuraray) and veneered with hybrid resin composite (Estenia C&B, Kuraray). Panavia F 2.0 (Kuraray) was used as resin luting cement. FRC-FDPs were loaded to failure in a universal testing machine. One-way ANOVA and Tukey's post-hoc test were used to evaluate the data. The four designs were analyzed with finite element analysis (FEA) to reveal the stress distribution within the tooth/restoration complex. Significantly lower fracture strengths were observed with inlay-retained FDPs (proximal box: 300 +/- 65 N; step-box: 309 +/- 37 N) compared to wing-retained FDPs (p < 0.05) (step-box-wing: 662 +/- 99 N; dual wing: 697 +/- 67 N). Proximal-box-, step-box-, and step-box-wing-retained FDPs mainly failed with catastrophic cusp fracture (proximal box 100%, step-box 100%, and step-box-wing 75%), while dual-wing-retained FDPs mainly failed at the adhesive interface and/or due to pontic failure (75%). FEA showed more favorable stress distributions within the tooth/restoration complex for dual wing retainers. A dual-wing retainer is the optimal design for replacement of a single premolar by means of a two-unit cantilever FRC-FDPs.

First fast-ion D-alpha (FIDA) measurements and simulations on C-2U

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolte, N. G., E-mail: nbolte@TriAlphaEnergy.com; Gupta, D.; Onofri, M.

2016-11-15

The first measurements of fast-ion D-alpha (FIDA) radiation have been acquired on C-2U, Tri Alpha Energy’s advanced, beam-driven field-reversed configuration (FRC). These measurements are also forward modeled by FIDASIM. This is the first measurement and simulation of FIDA carried out on an FRC topology. FIDA measurements are made of Doppler-shifted Balmer-alpha light from neutralized fast ions using a bandpass filter and photomultiplier tube. One adjustable line-of-sight measured signals at eight locations and eight times during the FRC lifetime over 26 discharges. Filtered signals include only the highest energy ions (>6 keV) and share some salient features with the FIDASIM result.more » Highly Doppler-shifted beam radiation is also measured with a high-speed camera and is spatially well-correlated with FIDASIM.« less

VUV Spectra observed in C-2 FRC plasma

NASA Astrophysics Data System (ADS)

Osin, Dmitry; Douglass, Jon; Tuszewski, Michel; TAE Team

2014-10-01

A grazing incidence flat-field spectrometer was installed for observation of vuv-spectra in C-2 FRC experiment. Wavelength calibration was done by observing spectra of six different gases produced by a hollow-cathode discharge lamp . In addition, in-situ calibration and alignment were performed utilizing neutral-beam heated gases. Wavelength regions between 16 nm and 170 nm was investigated with accuracy of about 0.02 nm. VUV-spectral lines of the most abundant impurity ions were identified both for Plasma Gun and C-2 plasmas. In addition to D spectrum, strong lines of O III-VI, N IV-V, C II-III, and Fe II ions were observed during the plasma lifetime. VUV radiative power losses within energy range from 7.3 eV to 81 eV were estimated based on the calculated FRC dimensions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, M. C., E-mail: mthompson@trialphaenergy.com; Gota, H.; Putvinski, S.

The C-2U experiment at Tri Alpha Energy studies the evolution of field-reversed configuration (FRC) plasmas sustained by neutral beam injection. Data on the FRC plasma performance are provided by a comprehensive suite of diagnostics that includes magnetic sensors, interferometry, Thomson scattering, spectroscopy, bolometry, reflectometry, neutral particle analyzers, and fusion product detectors. While many of these diagnostic systems were inherited from the preceding experiment C-2, C-2U has a variety of new and upgraded diagnostic systems: multi-chord far-infrared polarimetry, multiple fast imaging cameras with selectable atomic line filters, proton detector arrays, and 100 channel bolometer units capable of observing multiple regions ofmore » the spectrum simultaneously. In addition, extensive ongoing work focuses on advanced methods of measuring separatrix shape and plasma current profile that will facilitate equilibrium reconstruction and active control of the FRC plasma.« less

Predictive Models for Dynamic Brittle Fracture and Damage at High-velocity Impact in Multilayered Targets

DTIC Science & Technology

2016-11-01

layered glass/PC systems,Functionally Graded Materials (FGMs), polycrystalline AlON, and fiber-reinforced composite (FRC) materials. For the first time we...multi-layered glass/PC systems,Functionally Graded Materials (FGMs), polycrystalline AlON, and fiber-reinforced composite (FRC) materials. For the... Composite Lamina with Peridynamics, International Journal for Multiscale Computational Engineering, (12 2011): 0. doi: Florin Bobaru, Youn Doh Ha

The Fusion Gain Analysis of the Inductively Driven Liner Compression Based Fusion

NASA Astrophysics Data System (ADS)

Shimazu, Akihisa; Slough, John

2016-10-01

An analytical analysis of the fusion gain expected in the inductively driven liner compression (IDLC) based fusion is conducted to identify the fusion gain scaling at various operating conditions. The fusion based on the IDLC is a magneto-inertial fusion concept, where a Field-Reversed Configuration (FRC) plasmoid is compressed via the inductively-driven metal liner to drive the FRC to fusion conditions. In the past, an approximate scaling law for the expected fusion gain for the IDLC based fusion was obtained under the key assumptions of (1) D-T fuel at 5-40 keV, (2) adiabatic scaling laws for the FRC dynamics, (3) FRC energy dominated by the pressure balance with the edge magnetic field at the peak compression, and (4) the liner dwell time being liner final diameter divided by the peak liner velocity. In this study, various assumptions made in the previous derivation is relaxed to study the change in the fusion gain scaling from the previous result of G ml1 / 2 El11 / 8 , where ml is the liner mass and El is the peak liner kinetic energy. The implication from the modified fusion gain scaling on the performance of the IDLC fusion reactor system is also explored.

Functional residual capacity and airway resistance of the rat measured with a heat- and temperature-adjusted body plethysmograph.

PubMed

Tajiri, Sakurako; Kondo, Tetsuri; Yamabayashi, Hajime

2006-12-01

The functional residual capacity (FRC) and airway resistance (R(aw)) of the rat were measured, using a newly designed body plethysmograph (BPG), the inner environment of which was maintained at body temperature and was water-vapor saturated. The subjects were anesthetized and tracheally intubated male Wistar rats (n = 15). After measuring the FRC and R(aw), we analyzed the effects of inhaled methacholine (Mch, 0-8 mg/ml) on R(aw).The determined FRC was 5.37 +/- 0.22 ml (mean +/- SE). An almost linear relationship between box pressure and respiratory flow was obtained when the difference between box-gas temperature and the rectal temperature of the rat was less than 1.0 degrees C. The R(aw) at FRC was 0.230 +/- 0.017 cm H(2)O/ml/s. It increased proportionally with increases in the Mch concentration. When the dynamic changes in R(aw) were analyzed, the R(aw) was found to progressively increase during expiration; this increase continued throughout inspiration. Thus in the rat, R(aw) is not simply a function of changes in lung volume. In conclusion, the humidity- and temperature-adjusted BPG provided an absolute and possibly dynamic value of R(aw).

Insertional Mutations in the Hydrogenase vhc and frc Operons Encoding Selenium-Free Hydrogenases in Methanococcus voltae

PubMed Central

Berghofer, Y.; Klein, A.

1995-01-01

Methanococcus voltae, which contains four different gene groups that encode [NiFe]-hydrogenases, was transformed with integration vectors to achieve polar inactivation of two of the four hydrogenase operons that encode the selenium-free enzymes Vhc and Frc. Transformants which were selected by their acquired puromycin resistance showed site-specific insertions in either the vhc or frc operon by single crossover events. Southern hybridization revealed tandem integrations of whole vectors in the vhc operon, whereas only one vector copy was found in the frc operon. Northern (RNA) hybridizations showed a pac transcript of defined size, indicating strong termination in front of the hydrogenase genes downstream. In spite of the apparent abolition of expression of selenium-free hydrogenases through these polar insertions, they were not lethal to cells upon growth in selenium-deprived minimal medium, which we had previously shown to strongly induce transcription of the respective operons in M. voltae. Instead, like wild-type control cultures, transformants responded to selenium deprivation only with a reduction in growth rate. We conclude that loss of the potential to express a selenium-free hydrogenase can nevertheless be balanced by very small amounts of selenium hydrogenases under laboratory conditions in which the hydrogen supply is not likely to be a limiting growth factor. PMID:16535019

Sustainable Materials Management (SMM) Food Recovery Challenge (FRC) Data

EPA Pesticide Factsheets

As part of EPA's Food Recovery Challenge (FRC), organizations pledge to improve their sustainable food management practices and report their results. The FRC is part of EPA's Sustainable Materials Management Program (SMM). SMM seeks to reduce the environmental impact of materials through their entire life cycle. This includes how they are extracted, manufactured, distributed, used, reused, recycled, and disposed. Organizations are encouraged to follow the Food Recovery Hierarchy (https://www.epa.gov/sustainable-management-food/food-recovery-hierarchy) to prioritize their actions to prevent and divert wasted food. Each tier of the Food Recovery Hierarchy focuses on different management strategies for your wasted food. The program started in 2011 and the first data were made available in 2012. The FRC is part of EPA's larger SMM program (https://www.epa.gov/smm). Sustainable Materials Management (SMM) is a systemic approach to using and reusing materials more productively over their entire lifecycles. It represents a change in how our society thinks about the use of natural resources and environmental protection. By looking at a product's entire lifecycle we can find new opportunities to reduce environmental impacts, conserve resources, and reduce costs. There are multiple challenge programs available as part of the SMM program, including the Food Recovery Challenge, the Electronics Challenge, the Federal Green Challenge, and the WasteWise program.

Fiberglass distribution poles: A case study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, M.F.; Hosford, G.S.; Boozer, J.F. III

1995-01-01

This paper addresses the design considerations and manufacturing techniques along with mechanical test results of fiberglass reinforced composite (FRC) primary distribution poles. With it`s light weight, and virtually no maintenance it offers a viable alternative for use in remote and inaccessible locations. This paper also discusses a case study where seventy five FRC primary distribution poles have been installed on a distribution system in a remote area accessible only by foot and helicopter.

Flexural properties of three kinds of experimental fiber-reinforced composite posts.

PubMed

Kim, Mi-Joo; Jung, Won-Chang; Oh, Seunghan; Hattori, Masayuki; Yoshinari, Masao; Kawada, Eiji; Oda, Yutaka; Bae, Ji-Myung

2011-01-01

The aim of this study was to estimate the flexural properties of three kinds of experimental fiber-reinforced composite (FRC) posts and to evaluate their potential use as posts. Experimental FRC posts were fabricated with glass, aramid, and UHMWP fibers. Commercial FRC posts were used for comparison. A three-point bending test was performed at a crosshead speed of 1 mm/min. Experimental glass fiber posts showed significantly higher flexural strengths and moduli than aramid and UHMWP posts. Experimental UHMWP posts demonstrated superior toughness to the commercial posts. The glass fiber posts displayed stiff, strong and brittle features, while the UHMWP posts were flexible, weak and ductile. The flexural properties of the aramid posts fell between those of the glass and UHMWP posts. In conclusion, the glass fiber posts proved excellent in flexural strengths and moduli. However, the superior toughness of UHMWP fibers suggests the possibility of their use as posts in combination with glass fibers.

Parallel Transport with Sheath and Collisional Effects in Global Electrostatic Turbulent Transport in FRCs

NASA Astrophysics Data System (ADS)

Bao, Jian; Lau, Calvin; Kuley, Animesh; Lin, Zhihong; Fulton, Daniel; Tajima, Toshiki; Tri Alpha Energy, Inc. Team

2017-10-01

Collisional and turbulent transport in a field reversed configuration (FRC) is studied in global particle simulation by using GTC (gyrokinetic toroidal code). The global FRC geometry is incorporated in GTC by using a field-aligned mesh in cylindrical coordinates, which enables global simulation coupling core and scrape-off layer (SOL) across the separatrix. Furthermore, fully kinetic ions are implemented in GTC to treat magnetic-null point in FRC core. Both global simulation coupling core and SOL regions and independent SOL region simulation have been carried out to study turbulence. In this work, the ``logical sheath boundary condition'' is implemented to study parallel transport in the SOL. This method helps to relax time and spatial steps without resolving electron plasma frequency and Debye length, which enables turbulent transports simulation with sheath effects. We will study collisional and turbulent SOL parallel transport with mirror geometry and sheath boundary condition in C2-W divertor.

Suppressed ion-scale turbulence in a hot high-β plasma

NASA Astrophysics Data System (ADS)

Schmitz, L.; Fulton, D. P.; Ruskov, E.; Lau, C.; Deng, B. H.; Tajima, T.; Binderbauer, M. W.; Holod, I.; Lin, Z.; Gota, H.; Tuszewski, M.; Dettrick, S. A.; Steinhauer, L. C.

2016-12-01

An economic magnetic fusion reactor favours a high ratio of plasma kinetic pressure to magnetic pressure in a well-confined, hot plasma with low thermal losses across the confining magnetic field. Field-reversed configuration (FRC) plasmas are potentially attractive as a reactor concept, achieving high plasma pressure in a simple axisymmetric geometry. Here, we show that FRC plasmas have unique, beneficial microstability properties that differ from typical regimes in toroidal confinement devices. Ion-scale fluctuations are found to be absent or strongly suppressed in the plasma core, mainly due to the large FRC ion orbits, resulting in near-classical thermal ion confinement. In the surrounding boundary layer plasma, ion- and electron-scale turbulence is observed once a critical pressure gradient is exceeded. The critical gradient increases in the presence of sheared plasma flow induced via electrostatic biasing, opening the prospect of active boundary and transport control in view of reactor requirements.

Suppressed ion-scale turbulence in a hot high-β plasma

PubMed Central

Schmitz, L.; Fulton, D. P.; Ruskov, E.; Lau, C.; Deng, B. H.; Tajima, T.; Binderbauer, M. W.; Holod, I.; Lin, Z.; Gota, H.; Tuszewski, M.; Dettrick, S. A.; Steinhauer, L. C.

2016-01-01

An economic magnetic fusion reactor favours a high ratio of plasma kinetic pressure to magnetic pressure in a well-confined, hot plasma with low thermal losses across the confining magnetic field. Field-reversed configuration (FRC) plasmas are potentially attractive as a reactor concept, achieving high plasma pressure in a simple axisymmetric geometry. Here, we show that FRC plasmas have unique, beneficial microstability properties that differ from typical regimes in toroidal confinement devices. Ion-scale fluctuations are found to be absent or strongly suppressed in the plasma core, mainly due to the large FRC ion orbits, resulting in near-classical thermal ion confinement. In the surrounding boundary layer plasma, ion- and electron-scale turbulence is observed once a critical pressure gradient is exceeded. The critical gradient increases in the presence of sheared plasma flow induced via electrostatic biasing, opening the prospect of active boundary and transport control in view of reactor requirements. PMID:28000675

Comparative evaluation between glass and polyethylene fiber reinforced composites: A review of the current literature

PubMed Central

Mangoush, Enas; Säilynoja, Eija; Prinssi, Roosa; Lassila, Lippo; Vallittu, Pekka K.

2017-01-01

Background Fiber reinforced composite (FRC) is a promising class of material that gives clinicians alternative treatment options. There are many FRC products available in the market based on either glass or polyethylene fiber type. The aim of this study was to present a comparison between glass and polyethylene fiber reinforced composites based on available literature review. Material and Methods A thorough literature search, with no limitation, was done up to June 2017. The range of relevant publications was surveyed using PubMed and Google Scholar. From the search results, articles related to our search terms were only considered. An assessment of these articles was done by two individuals in order to include only articles directly compare between glass and polyethylene FRCs. The search terms used were “fiber reinforced dental composites” and “glass and polyethylene fibers in dentistry”. Results The search provided 276 titles. Full-text analysis was performed for 29 articles that met the inclusion criteria. Most were laboratory-based research with various test specimen designs prepared according to ISO standard or with extracted teeth and only three articles were clinical studies. Most of studies (n=23) found superior characteristics of glass FRCs over polyethylene FRCs. Conclusions Significant reinforcement differences between commercial glass and polyethylene fiber reinforced composites were found. Key words:Fiber reinforced composite, glass fiber, polyethylene fiber. PMID:29410756

Optimizing lung aeration at birth using a sustained inflation and positive pressure ventilation in preterm rabbits

PubMed Central

te Pas, Arjan B.; Kitchen, Marcus J.; Lee, Katie; Wallace, Megan J.; Fouras, Andreas; Lewis, Robert A.; Yagi, Naoto; Uesugi, Kentaro; Hooper, Stuart B.

2016-01-01

Background: A sustained inflation (SI) facilitates lung aeration, but the most effective pressure and duration are unknown. We investigated the effect of gestational age (GA) and airway liquid volume on the required inflation pressure and SI duration. Methods: Rabbit kittens were delivered at 27, 29, and 30 d gestation, intubated and airway liquid was aspirated. Either no liquid (control) or 30 ml/kg of liquid was returned to the airways. Lung gas volumes were measured by plethysmography and phase-contrast X-ray-imaging. Starting at 22 cmH2O, airway pressure was increased until airflow commenced and pressure was then held constant. The SI was truncated when 20 ml/kg air had entered the lung and ventilation continued with intermittent positive pressure ventilation (iPPV). Results: Higher SI pressures and longer durations were required in 27-d kittens compared to 30-d kittens. During iPPV, 27-d kittens needed higher pressures and had lower functional residual capacity (FRC) compared to 30-d kittens. Adding lung liquid increased SI duration, reduced FRC, and increased resistance and pressures during iPPV in 29- and 30-d kittens. Conclusion: Immature kittens required higher starting pressures and longer SI durations to achieve a set inflation volume. Larger airway liquid volumes adversely affected lung function during iPPV in older but not young kittens. PMID:26991259

Adhesive retention of experimental fiber-reinforced composite, orthodontic acrylic resin, and aliphatic urethane acrylate to silicone elastomer for maxillofacial prostheses.

PubMed

Kosor, Begüm Yerci; Artunç, Celal; Şahan, Heval

2015-07-01

A key factor of an implant-retained facial prosthesis is the success of the bonding between the substructure and the silicone elastomer. Little has been reported on the bonding of fiber reinforced composite (FRC) to silicone elastomers. Experimental FRC could be a solution for facial prostheses supported by light-activated aliphatic urethane acrylate, orthodontic acrylic resin, or commercially available FRCs. The purpose of this study was to evaluate the bonding of the experimental FRC, orthodontic acrylic resin, and light-activated aliphatic urethane acrylate to a commercially available high-temperature vulcanizing silicone elastomer. Shear and 180-degree peel bond strengths of 3 different substructures (experimental FRC, orthodontic acrylic resin, light-activated aliphatic urethane acrylate) (n=15) to a high-temperature vulcanizing maxillofacial silicone elastomer (M511) with a primer (G611) were assessed after 200 hours of accelerated artificial light-aging. The specimens were tested in a universal testing machine at a cross-head speed of 10 mm/min. Data were collected and statistically analyzed by 1-way ANOVA, followed by the Bonferroni correction and the Dunnett post hoc test (α=.05). Modes of failure were visually determined and categorized as adhesive, cohesive, or mixed and were statistically analyzed with the chi-squared goodness-of-fit test (α=.05). As the mean shear bond strength values were evaluated statistically, no difference was found among the experimental FRC, aliphatic urethane acrylate, and orthodontic acrylic resin subgroups (P>.05). The mean peel bond strengths of experimental fiber reinforced composite and aliphatic urethane acrylate were not found to be statistically different (P>.05). The mean value of the orthodontic acrylic resin subgroup peel bond strength was found to be statistically lower (P<.05). Shear test failure types were found to be statistically different (P<.05), whereas 180-degree peel test failure types were not found to be statistically significant (P>.05). Shear forces predominantly exhibited cohesive failure (64.4%), whereas peel forces predominantly exhibited adhesive failure (93.3%). The mean shear bond strengths of the experimental FRC and aliphatic urethane acrylate groups were not found to be statistically different (P>.05). The mean value of the 180-degree peel strength of the orthodontic acrylic resin group was found to be lower (P<.05). Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Implementing New Non-Chromate Coatings Systems (Briefing Charts)

DTIC Science & Technology

2011-02-09

Initiate Cr6+ authorization process for continued Cr6+ use using the form, Authorization to Use Hexavalent Chromium. YES NO • Approval of...Aluminum and magnesium anodizing • Hard Chrome Plating • Type II conversion coating on aluminum alloys under chromated primer • Type II conversion coating...Elimination of Hexavalent Chromium 80% 5% 14% 1% Type II Type III Type IC Type IC Fatigue Critical 50% 50% Type II Type IC FRC-SE (JAX) Fully Integrated FRC

Fiber-reinforced composite substructure: load-bearing capacity of an onlay restoration and flexural properties of the material.

PubMed

Garoushi, Sufyan K; Lassila, Lippo V J; Tezvergil, Arzu; Vallittu, Pekka K

2006-09-01

The aim of this study was to determine the static load-bearing capacity of composite resin onlay restorations made of particulate filler composite (PFC) with two different types of fiber-reinforced composite (FRC) substructures. In addition, flexural properties of the material combination and the effect of polymerization devices were tested. Specimens were prepared to simulate an onlay restoration, which consisted of 2 to 3 mm of FRC layer as a substructure (short random and continuous bidirectional fiber orientation) and a 1 mm surface layer of PFC. Control specimens were prepared from plain PFC. In Group A the specimens were incrementally polymerized only with a hand-light curing unit for 40 s, while in Group B the specimens were post-cured in a light-curing oven for 15 min before they were statically loaded with a steel ball. Bar-shaped test specimens were prepared to measure the flexural properties of material combination using a three-point bending test (ISO 10477). Analysis of variance (ANOVA) revealed all specimens with a FRC substructure have higher values of static load-bearing capacity and flexural properties than those obtained with plain PFC (p<0.001). The load-bearing capacity of all the specimens decreased after post-curing and water storage. Restorations made from a material combination of FRC and PFC showed better mechanical properties than those obtained with plain PFC.

Spectroscopic Measurement of Ion Flow During Merging Start-up of Field-Reversed Configuration

NASA Astrophysics Data System (ADS)

Oka, Hirotaka; Inomoto, Michiaki; Tanabe, Hiroshi; Annoura, Masanobu; Ono, Yasushi; Nemoto, Koshichi

2012-10-01

The counter-helicity merging method [1] of field-reversed configuration (FRC) formation involves generation of bidirectional toroidal flow, known as a ``sling-shot.'' In two fluids regime, reconnection process is strongly affected by the Hall effect [2]. In this study, we have investigated the behavior of toroidal bidirectional flow generated by the counter-helicity merging in two-fluids regime. We use 2D Ion Doppler Spectroscopy to mesure toroidal ion flow during merging start-up of FRC from Ar gas. We defined two cases: one case with a radially pushed-in X line (case I) and the other case with a radially pushed-out X line(case O). The flow during the plasma merging shows radial asymmetry, as expected from the magnetic measurement, but finally relaxes to a unidirectional flow in plasma current direction in both cases. We observed larger toroidal flow in the plasma current direction in case I after FRC is formed, though the FRC in case O has larger magnetic flux. These results suggest that more ions are lost during merging start-up in case I. This selective ion loss might account for stability and confinement of FRCs probably maintained by high energy ions.[4pt] [1] Y. Ono, et al., Nucl. Fusion 39, pp. 2001-2008 (1999).[0pt] [2] M. Inomoto, et al., Phys. Rev. Lett., 97, 135002, (2006)

Design and Construction of Field Reversed Configuration Plasma Chamber for Plasma Material Interaction Studies

NASA Astrophysics Data System (ADS)

Smith, DuWayne L.

A Field Reversed Configuration (FRC) plasma source was designed and constructed to conduct high energy plasma-materials interaction studies. The purpose of these studies is the development of advanced materials for use in plasma based electric propulsion systems and nuclear fusion containment vessels. Outlined within this thesis is the basic concept of FRC plasmoid creation, an overview of the device design and integration of various diagnostics systems for plasma conditions and characterization, discussion on the variety of material defects resulting from the plasma exposure with methods and tools designed for characterization. Using a Michelson interferometer it was determined that the FRC plasma densities are on the order of ~1021 m-3. A novel dynamic pressure probe was created to measure ion velocities averaging 300 km/s. Compensating flux loop arrays were used to measure magnetic field strength and verify the existence of the FRC plasmoid and when used in combination with density measurements it was determined that the average ion temperatures are ~130 eV. X-ray Photoelectron Spectroscopy (XPS) was employed as a means of characterizing the size and shape of the plasma jet in the sample exposure positions. SEM results from preliminary studies reveal significant morphological changes on plasma facing material surfaces, and use of XRD to elucidate fuel gas-ion implantation strain rates correlated to plasma exposure energies.

3D-Finite element analysis of molars restored with endocrowns and posts during masticatory simulation.

PubMed

Dejak, Beata; Młotkowski, Andrzej

2013-12-01

The objective was to compare equivalent stresses in molars restored with endocrowns as well as posts and cores during masticatory simulation using finite element analysis. Four three-dimensional models of first mandibular molars were created: A - intact tooth; B - tooth restored by ceramic endocrown; C - tooth with FRC posts, composite core and ceramic crown; D - tooth with cast post and ceramic crown. The study was performed using finite element analysis, with contact elements. The computer simulations of mastication were conducted. The equivalent stresses of modified von Mises failure criterion (mvM) in models were calculated, Tsai-Wu index for FRC post was determinate. Maximal values of the stresses in the ceramic, cement and dentin were compared between models and to strength of the materials. Contact stresses in the cement-tissue adhesive interface around restorations were considered as well. During masticatory simulation, the lowest mvM stresses in dentin arisen in molar restored with endocrown (Model B). Maximal mvM stress values in structures of restored molar were 23% lower than in the intact tooth. The mvM stresses in the endocrown did not exceed the tensile strength of ceramic. In the molar with an FRC posts (Model C), equivalent stress values in dentin increased by 42% versus Model B. In ceramic crown of Model C the stresses were 31% higher and in the resin luting cement were 61% higher than in the tooth with endocrown. Tensile contact stresses in the adhesive cement-dentin interface around FRC posts achieved 4 times higher values than under endocrown and shear stresses increased twice. The contact stress values around the appliances were several time smaller than cement-dentin bond strength. Teeth restored by endocrowns are potentially more resistant to failure than those with FRC posts. Under physiological loads, ceramic endocrowns ideally cemented in molars should not be demaged or debonded. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Simplifying the assessment of coronary artery stenosis by enhancing instantaneous wave free ratio.

PubMed

Spagnoli, Vincent; Picard, Fabien; Tadros, Victor-Xavier; Cournoyer, Daniel; Doucet, Serge; Tanguay, Jean François; Gosselin, Gilbert; de Guise, Pierre; Gallo, Richard

2018-04-01

Instantaneous wave free ratio (iFR) does not require adenosine, but has a relatively wide intermediate range where functional assessment remains inconclusive. In this pilot study, we sought to enhance iFR through with the use of intracoronary (IC) saline (iFRs) and contrast media (iFRc) and determine whether these techniques correlated well with fractional flow reserve (FFR). Patients with coronary artery stenosis (CAS) associated with an iFR in the intermediate zone (≥0.86 and ≤0.93) were prospectively assessed with resting distal coronary pressure/aorta pressure (Pd/Pa), iFR, iFRs, iFRc and FFR. A total of 40 coronary lesions were studied (40 patients). Pearson correlation coefficients for FFR and iFR, FFR and iFRs, FFR and iFRc were respectively: 0.57 (P=0.0002), 0.80 (P<0.0001) and 0.77 (P<0.0001). Receiver-operating characteristic (ROC) curve analysis showed similar area under the curve (AUC) of iFRs and iFR [0.90 (95% CI: 0.76-1) vs. 0.89 (95% CI: 0.79-0.99), P=0.89]. Youden's index established cut-off values of ≤0.90 for iFR (sensitivity =91%, specificity =74%) and ≤0.78 for iFRs (sensitivity =73%, specificity =100%). In contrast, the AUC of iFRc was superior to the AUC of iFR [0.99 (95% CI: 0.98-1), P=0.049]. iFRc showed excellent accuracy and established cut-off values of ≤0.81 in predicting an FFR value of ≤0.80 (sensitivity =100%, specificity =93%). When iFR is in the intermediate zone, functional assessment of CAS by iFR is enhanced with the use of contrast media but not saline. This pilot study could be hypothesis generating for further study to enhance iFR specificity and sensibility.

Methanospirillum respiratory mRNA biomarkers correlate with hydrogenotrophic methanogenesis rate during growth and competition for hydrogen in an organochlorine-respiring mixed culture.

PubMed

Rowe, Annette R; Mansfeldt, Cresten B; Heavner, Gretchen L; Richardson, Ruth E

2013-01-02

Molecular biomarkers hold promise for inferring rates of key metabolic activities in complex microbial systems. However, few studies have assessed biomarker levels for simultaneously occurring (and potentially competing) respirations. In this study, methanogenesis biomarkers for Methanospirillum hungatei were developed, tested, and compared to Dehalococcoides mccartyi biomarkers in a well-characterized mixed culture. Proteomic analyses of mixed culture samples (n = 4) confirmed expression of many M. hungatei methanogenesis enzymes. The mRNAs for two oxidoreductases detected were explored as quantitative biomarkers of hydrogenotrophic methanogenesis: a coenzyme F(420)-reducing hydrogenase (FrcA) and an iron sulfur protein (MvrD). As shown previously in D. mccartyi, M. hungatei transcript levels correlated linearly with measured (R = 0.97 for FrcA, R = 0.91 for MvrD; n = 7) or calculated respiration rate (R = 0.81 for FrcA, R = 0.62 for MvrD; n = 35) across two orders of magnitude on a log-log scale. The average abundance of MvrD transcripts was consistently two orders of magnitude lower than FrcA, regardless of experimental condition. In experiments where M. hungatei was competing for hydrogen with D. mccartyi, transcripts for the key respiratory hydrogenase HupL were generally less abundant per mL than FrcA and more abundant than MvrD. With no chlorinated electron acceptor added, HupL transcripts fell below both targets. These biomarkers hold promise for the prediction of in situ rates of respiration for these microbes, even when growing in mixed culture and utilizing a shared substrate which has important implications for both engineered and environmental systems. However, the differences in overall biomarker abundances suggest that the strength of any particular mRNA biomarker relies upon empirically established quantitative trends under a range of pertinent conditions.

Influence of perioperative oxygen fraction on pulmonary function after abdominal surgery: a randomized controlled trial

PubMed Central

2012-01-01

Background A high perioperative inspiratory oxygen fraction (FiO2) may reduce the frequency of surgical site infection. Perioperative atelectasis is caused by absorption, compression and reduced function of surfactant. It is well accepted, that ventilation with 100% oxygen for only a few minutes is associated with significant formation of atelectasis. However, it is still not clear if a longer period of 80% oxygen results in more atelectasis compared to a low FiO2. Our aim was to assess if a high FiO2 is associated with impaired oxygenation and decreased pulmonary functional residual capacity (FRC). Methods Thirty-five patients scheduled for laparotomy for ovarian cancer were randomized to receive either 30% oxygen (n = 15) or 80% oxygen (n = 20) during and for 2 h after surgery. The oxygenation index (PaO2/FiO2) was measured every 30 min during anesthesia and 90 min after extubation. FRC was measured the day before surgery and 2 h after extubation by a rebreathing method using the inert gas SF6. Results Five min after intubation, the median PaO2/FiO2 was 69 kPa [53-71] in the 30%-group vs. 60 kPa [47-69] in the 80%-group (P = 0.25). At the end of anesthesia, the PaO2/FiO2 was 58 kPa [40-70] vs. 57 kPa [46-67] in the 30%- and 80%-group, respectively (P = 0.10). The median FRC was 1993 mL [1610-2240] vs. 1875 mL [1545-2048] at baseline and 1615 mL [1375-2318] vs. 1633 mL [1343-1948] postoperatively in the 30%- and 80%-group, respectively (P = 0.70). Conclusion We found no significant difference in oxygenation index or functional residual capacity between patients given 80% and 30% oxygen for a period of approximately 5 hours. Trial registration ClinicalTrials.gov Identifier: NCT00637936. PMID:22840231

Replacement of missing teeth with fiber-reinforced composite FPDs: clinical protocol.

PubMed

Bouillaguet, Serge; Schütt, Andrea; Marin, Isabelle; Etechami, Leila; Di Salvo, Giancarlo; Krejci, Ivo

2003-04-01

The concept of minimally invasive preparation protocols has resulted in reduced loss of critical tooth structures and maintenance of optimal strength, form, and aesthetics. While various treatment options have been described for single-tooth replacement, fiber-reinforced composite (FRC) fixed partial dentures (FPDs) provide a viable treatment alternative with proven mechanical properties, aesthetics, and function. This article presents several clinical scenarios in which minimally invasive adhesive FRC FPDs are provided to deliver enhanced predictability, strength, and durability.

A fiber-reinforced composite prosthesis restoring a lateral midfacial defect: a clinical report.

PubMed

Kurunmäki, Hemmo; Kantola, Rosita; Hatamleh, Muhanad M; Watts, David C; Vallittu, Pekka K

2008-11-01

This clinical report describes the use of a glass fiber-reinforced composite (FRC) substructure to reinforce the silicone elastomer of a large facial prosthesis. The FRC substructure was shaped into a framework and embedded into the silicone elastomer to form a reinforced facial prosthesis. The prosthesis is designed to overcome the disadvantages associated with traditionally fabricated prostheses; namely, delamination of the silicone of the acrylic base, poor marginal adaptation over time, and poor simulation of facial expressions.

Background radioactivity in sediments near Los Alamos, New Mexico.

PubMed

McLin, Stephen G

2004-07-26

River and reservoir sediments have been collected annually by Los Alamos National Laboratory since 1974 and 1979, respectively. These background samples are collected from five river stations and four reservoirs located throughout northern New Mexico and southern Colorado. Analyses include 3H, 90Sr, 137Cs, total U, 238Pu, 239,240Pu, 241Am, gross alpha, gross beta, and gross gamma radioactivity. Surprisingly, there are no federal or state regulatory standards in the USA that specify how to compute background radioactivity values on sediments. Hence, the sample median (or 0.50 quantile) is proposed for this background because it reflects central data tendency and is distribution-free. Estimates for the upper limit of background radioactivity on river and reservoir sediments are made for sampled analytes using the 0.95 quantile (two-tail). These analyses also show that seven of ten analytes from reservoir sediments are normally distributed, or are normally distributed after a logarithmic or square root transformation. However, only three of ten analytes from river sediments are similarly distributed. In addition, isotope ratios for 137Cs/238Pu, 137Cs/239,240Pu, and 239,240Pu/238Pu from reservoir sediments are independent of clay content, total organic carbon/specific surface area (TOC/SSA) and cation exchange capacity/specific surface area (CEC/SSA) ratios. These TOC/SSA and CEC/SSA ratios reflect sediment organic carbon and surface charge densities that are associated with radionuclide absorption, adsorption, and ion exchange reactions on clay mineral structures. These latter ratio values greatly exceed the availability of background radionuclides in the environment, and insure that measured background levels are a maximum. Since finer-grained reservoir sediments contain larger clay-sized fractions compared to coarser river sediments, they show higher background levels for most analytes. Furthermore, radioactivity values on reservoir sediments have remained relatively constant since the early 1980s. These results suggest that clay contents in terrestrial sediments are often more important at concentrating background radionuclides than many other environmental factors, including geology, climate and vegetation. Hence, reservoirs and floodplains represent ideal radionuclide sampling locations because fine-grained materials are more easily trapped here. Ultimately, most of these differences still reflect spatial and temporal variability originating from global atmospheric nuclear weapons testing and disintegration of nuclear-powered satellites upon atmospheric reentry. Copyright 2004 Elsevier B.V.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slough, John

The entry of fusion as a viable, competitive source of power has been stymied by the challenge of finding an economical way to provide for the confinement and heating of the plasma fuel. The main impediment for current nuclear fusion concepts is the complexity and large mass associated with the confinement systems. To take advantage of the smaller scale, higher density regime of magnetic fusion, an efficient method for achieving the compressional heating required to reach fusion gain conditions must be found. The very compact, high energy density plasmoid commonly referred to as a Field Reversed Configuration (FRC) provides formore » an ideal target for this purpose. To make fusion with the FRC practical, an efficient method for repetitively compressing the FRC to fusion gain conditions is required. A novel approach to be explored in this endeavor is to remotely launch a converging array of small macro-particles (macrons) that merge and form a more massive liner inside the reactor which then radially compresses and heats the FRC plasmoid to fusion conditions. The closed magnetic field in the target FRC plasmoid suppresses the thermal transport to the confining liner significantly lowering the imploding power needed to compress the target. With the momentum flux being delivered by an assemblage of low mass, but high velocity macrons, many of the difficulties encountered with the liner implosion power technology are eliminated. The undertaking to be described in this proposal is to evaluate the feasibility achieving fusion conditions from this simple and low cost approach to fusion. During phase I the design and testing of the key components for the creation of the macron formed liner have been successfully carried out. Detailed numerical calculations of the merging, formation and radial implosion of the Macron Formed Liner (MFL) were also performed. The phase II effort will focus on an experimental demonstration of the macron launcher at full power, and the demonstration of megagauss magnetic field compression by a small array of full scale macrons. In addition the physics of the compression of an FRC to fusion conditions will be undertaken with a smaller scale MFL. The timescale for testing will be rapidly accelerated by taking advantage of other facilities at MSNW where the target FRC will be created and translated inside the MFL just prior to implosion of the MFL. Experimental success would establish the concept at the proof of principle level and the following phase III effort would focus on the full development of the concept into a fusion gain device. Successful operation would lead to several benefits in various fields. It would have application to high energy density physics, as well as nuclear waste transmutation and alternate fission fuel cycles. The smaller scale device could find immediate application as an intense source of neutrons for diagnostic imaging and non-invasive object interrogation.« less

Hall effect on a Merging Formation Process of a Field-Reversed Configuration

NASA Astrophysics Data System (ADS)

Kaminou, Yasuhiro; Guo, Xuehan; Inomoto, Michiaki; Ono, Yasushi; Horiuchi, Ritoku

2015-11-01

Counter-helicity spheromak merging is one of the formation methods of a Field-Reversed Configuration (FRC). In counter-helicity spheromak merging, two spheromaks with opposing toroidal fields merge together, through magnetic reconnection events and relax into a FRC, which has no or little toroidal field. This process contains magnetic reconnection and a relaxation phenomena, and the Hall effect has some essential effects on these process because the X-point in the magnetic reconnection or the O-point of the FRC has no or little magnetic field. However, the Hall effect as both global and local effect on counter-helicity spheromak merging has not been elucidated. In this poster, we conducted 2D/3D Hall-MHD simulations and experiments of counter-helicity spheromak merging. We find that the Hall effect enhances the reconnection rate, and reduces the generation of toroidal sheared-flow. The suppression of the ``slingshot effect'' affects the relaxation process. We will discuss details in the poster.

Simulation of drift wave instability in field-reversed configurations using global magnetic geometry

NASA Astrophysics Data System (ADS)

Fulton, D. P.; Lau, C. K.; Lin, Z.; Tajima, T.; Holod, I.; the TAE Team

2016-10-01

Minimizing transport in the field-reversed configuration (FRC) is essential to enable FRC-based fusion reactors. Recently, significant progress on advanced beam-driven FRCs in C-2 and C-2U (at Tri Alpha Energy) provides opportunities to study transport properties using Doppler backscattering (DBS) measurements of turbulent fluctuations and kinetic particle-in-cell simulations of driftwaves in realistic equilibria via the Gyrokinetic Toroidal Code (GTC). Both measurements and simulations indicate relatively small fluctuations in the scrape-off layer (SOL). In the FRC core, local, single flux surface simulations reveal strong stabilization, while experiments indicate quiescent but finite fluctuations. One possible explanation is that turbulence may originate in the SOL and propagate at very low levels across the separatrix into the core. To test this hypothesis, a significant effort has been made to develop A New Code (ANC) based on GTC physics formulations, but using cylindrical coordinates which span the magnetic separatrix, including both core and SOL. Here, we present first results from global ANC simulations.

Biodiversity and community composition of sediment macrofauna associated with deep-sea Lophelia pertusa habitats in the Gulf of Mexico

USGS Publications Warehouse

Demopoulos, Amanda W.J.; Bourque, Jill R.; Frometa, Janessy

2014-01-01

Scleractinian corals create three-dimensional reefs that provide sheltered refuges, facilitate sediment accumulation, and enhance colonization of encrusting fauna. While heterogeneous coral habitats can harbor high levels of biodiversity, their effect on the community composition within nearby sediments remains unclear, particularly in the deep sea. Sediment macrofauna from deep-sea coral habitats (Lophelia pertusa) and non-coral, background sediments were examined at three sites in the northern Gulf of Mexico (VK826, VK906, MC751, 350–500 m depth) to determine whether macrofaunal abundance, diversity, and community composition near corals differed from background soft-sediments. Macrofaunal densities ranged from 26 to 125 individuals 32 cm−2 and were significantly greater near coral versus background sediments only at VK826. Of the 86 benthic invertebrate taxa identified, 16 were exclusive to near-coral habitats, while 14 were found only in background sediments. Diversity (Fisher’s α) and evenness were significantly higher within near-coral sediments only at MC751 while taxon richness was similar among all habitats. Community composition was significantly different both between near-coral and background sediments and among the three primary sites. Polychaetes numerically dominated all samples, accounting for up to 70% of the total individuals near coral, whereas peracarid crustaceans were proportionally more abundant in background sediments (18%) than in those near coral (10%). The reef effect differed among sites, with community patterns potentially influenced by the size of reef habitat. Taxon turnover occurred with distance from the reef, suggesting that reef extent may represent an important factor in structuring sediment communities near L. pertusa. Polychaete communities in both habitats differed from other Gulf of Mexico (GOM) soft sediments based on data from previous studies, and we hypothesize that local environmental conditions found near L. pertusa may influence the macrofaunal community structure beyond the edges of the reef. This study represents the first assessment of L. pertusa-associated sediment communities in the GOM and provides baseline data that can help define the role of transition zones, from deep reefs to soft sediments, in shaping macrofaunal community structure and maintaining biodiversity; this information can help guide future conservation and management activities.

Infant multiple breath washout using a new commercially available device: Ready to replace the previous setup?

PubMed

Kentgens, Anne-Christianne; Guidi, Marisa; Korten, Insa; Kohler, Lena; Binggeli, Severin; Singer, Florian; Latzin, Philipp; Anagnostopoulou, Pinelopi

2018-05-01

Multiple breath washout (MBW) is a sensitive test to measure lung volumes and ventilation inhomogeneity from infancy on. The commonly used setup for infant MBW, based on ultrasonic flowmeter, requires extensive signal processing, which may reduce robustness. A new setup may overcome some previous limitations but formal validation is lacking. We assessed the feasibility of infant MBW testing with the new setup and compared functional residual capacity (FRC) values of the old and the new setup in vivo and in vitro. We performed MBW in four healthy infants and four infants with cystic fibrosis, as well as in a Plexiglas lung simulator using realistic lung volumes and breathing patterns, with the new (Exhalyzer D, Spiroware 3.2.0, Ecomedics) and the old setup (Exhalyzer D, WBreath 3.18.0, ndd) in random sequence. The technical feasibility of MBW with the new device-setup was 100%. Intra-subject variability in FRC was low in both setups, but differences in FRC between the setups were considerable (mean relative difference 39.7%, range 18.9; 65.7, P = 0.008). Corrections of software settings decreased FRC differences (14.0%, -6.4; 42.3, P = 0.08). Results were confirmed in vitro. MBW measurements with the new setup were feasible in infants. However, despite attempts to correct software settings, outcomes between setups were not interchangeable. Further work is needed before widespread application of the new setup can be recommended. © 2018 Wiley Periodicals, Inc.

Palmitate Attenuates Osteoblast Differentiation of Fetal Rat Calvarial Cells

PubMed Central

Yeh, Lee-Chuan C.; Ford, Jeffery J.; Lee, John C.; Adamo, Martin L.

2014-01-01

Aging is associated with the accumulation of ectopic lipid resulting in the inhibition of normal organ function, a phenomenon known as lipotoxicity. Within the bone marrow microenvironment, elevation in fatty acid levels may produce an increase in osteoclast activity and a decrease in osteoblast number and function, thus contributing to age-related osteoporosis. However, little is known about lipotoxic mechanisms in intramembraneous bone. Previously we reported that the long chain saturated fatty acid palmitate inhibited the expression of the osteogenic markers RUNX2 and osteocalcin in fetal rat calvarial cell (FRC) cultures. Moreover, the acetyl Co-A carboxylase inhibitor TOFA blocked the inhibitory effect of palmitate on expression of these two markers. In the current study we have extended these observations to show that palmitate inhibits spontaneous mineralized bone formation in FRC cultures in association with reduced mRNA expression of RUNX2, alkaline phosphatase, osteocalcin, and bone sialoprotein and reduced alkaline phosphatase activity. The effects of palmitate on osteogenic marker expression were inhibited by TOFA. Palmitate also inhibited the mRNA expression of fatty acid synthase and PPAR gamma in FRC cultures, and as with osteogenic markers, this effect was inhibited by TOFA. Palmitate had no effect on FRC cell proliferation or apoptosis, but inhibited BMP-7-induced alkaline phosphatase activity. We conclude that palmitate accumulation may lead to lipotoxic effects on osteoblast differentiation and mineralization and that increases in fatty acid oxidation may help to prevent these lipotoxic effects. PMID:24955854

Palmitate attenuates osteoblast differentiation of fetal rat calvarial cells.

PubMed

Yeh, Lee-Chuan C; Ford, Jeffery J; Lee, John C; Adamo, Martin L

2014-07-18

Aging is associated with the accumulation of ectopic lipid resulting in the inhibition of normal organ function, a phenomenon known as lipotoxicity. Within the bone marrow microenvironment, elevation in fatty acid levels may produce an increase in osteoclast activity and a decrease in osteoblast number and function, thus contributing to age-related osteoporosis. However, little is known about lipotoxic mechanisms in intramembraneous bone. Previously we reported that the long chain saturated fatty acid palmitate inhibited the expression of the osteogenic markers RUNX2 and osteocalcin in fetal rat calvarial cell (FRC) cultures. Moreover, the acetyl CoA carboxylase inhibitor TOFA blocked the inhibitory effect of palmitate on expression of these two markers. In the current study we have extended these observations to show that palmitate inhibits spontaneous mineralized bone formation in FRC cultures in association with reduced mRNA expression of RUNX2, alkaline phosphatase, osteocalcin, and bone sialoprotein and reduced alkaline phosphatase activity. The effects of palmitate on osteogenic marker expression were inhibited by TOFA. Palmitate also inhibited the mRNA expression of fatty acid synthase and PPARγ in FRC cultures, and as with osteogenic markers, this effect was inhibited by TOFA. Palmitate had no effect on FRC cell proliferation or apoptosis, but inhibited BMP-7-induced alkaline phosphatase activity. We conclude that palmitate accumulation may lead to lipotoxic effects on osteoblast differentiation and mineralization and that increases in fatty acid oxidation may help to prevent these lipotoxic effects. Copyright © 2014 Elsevier Inc. All rights reserved.

Impact of mercury on denitrification and denitrifying microbial communities in nitrate enrichments of subsurface sediments.

PubMed

Wang, Yanping; Wiatrowski, Heather A; John, Ria; Lin, Chu-Ching; Young, Lily Y; Kerkhof, Lee J; Yee, Nathan; Barkay, Tamar

2013-02-01

The contamination of groundwater with mercury (Hg) is an increasing problem worldwide. Yet, little is known about the interactions of Hg with microorganisms and their processes in subsurface environments. We tested the impact of Hg on denitrification in nitrate reducing enrichment cultures derived from subsurface sediments from the Oak Ridge Integrated Field Research Challenge site, where nitrate is a major contaminant and where bioremediation efforts are in progress. We observed an inverse relationship between Hg concentrations and onset and rates of denitrification in nitrate enrichment cultures containing between 53 and 1.1 μM of inorganic Hg; higher Hg concentrations increasingly extended the time to onset of denitrification and inhibited denitrification rates. Microbial community complexity, as indicated by terminal restriction fragment length polymorphism (tRFLP) analysis of the 16S rRNA genes, declined with increasing Hg concentrations; at the 312 nM Hg treatment, a single tRFLP peak was detected representing a culture of Bradyrhizobium sp. that possessed the merA gene indicating a potential for Hg reduction. A culture identified as Bradyrhizobium sp. strain FRC01 with an identical 16S rRNA sequence to that of the enriched peak in the tRFLP patterns, reduced Hg(II) to Hg(0) and carried merA whose amino acid sequence has 97 % identity to merA from the Proteobacteria and Firmicutes. This study demonstrates that in subsurface sediment incubations, Hg may inhibit denitrification and that inhibition may be alleviated when Hg resistant denitrifying Bradyrhizobium spp. detoxify Hg by its reduction to the volatile elemental form.

Background Radioactivity in River and Reservoir Sediments near Los Alamos, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

S.G.McLin; D.W. Lyons

2002-05-05

As part of its continuing Environmental Surveillance Program, regional river and lake-bottom sediments have been collected annually by Los Alamos National Laboratory (the Laboratory) since 1974 and 1979, respectively. These background samples are collected from three drainage basins at ten different river stations and five reservoirs located throughout northern New Mexico and southern Colorado. Radiochemical analyses for these sediments include tritium, strontium-90, cesium-137, total uranium, plutonium-238, plutonium-239,-240, americium-241, gross alpha, gross beta, and gross gamma radioactivity. Detection-limit radioactivity originates as worldwide fallout from aboveground nuclear weapons testing and satellite reentry into Earth's atmosphere. Spatial and temporal variations in individual analytemore » levels originate from atmospheric point-source introductions and natural rate differences in airborne deposition and soil erosion. Background radioactivity values on sediments reflect this variability, and grouped river and reservoir sediment samples show a range of statistical distributions that appear to be analyte dependent. Traditionally, both river and reservoir analyte data were blended together to establish background levels. In this report, however, we group background sediment data according to two criteria. These include sediment source (either river or reservoir sediments) and station location relative to the Laboratory (either upstream or downstream). These grouped data are statistically evaluated through 1997, and background radioactivity values are established for individual analytes in upstream river and reservoir sediments. This information may be used to establish the existence and areal extent of trace-level environmental contamination resulting from historical Laboratory research activities since the early 1940s.« less

Importance of background values in assessing the impact of heavy metals in river ecosystems: case study of Tisza River, Serbia.

PubMed

Štrbac, Snežana; Kašanin Grubin, Milica; Vasić, Nebojša

2017-11-30

The main objective of this paper is to evaluate how a choice of different background values may affect assessing the anthropogenic heavy metal pollution in sediments from Tisza River (Serbia). The second objective of this paper is to underline significance of using geochemical background values when establishing quality criteria for sediment. Enrichment factor (EF), geoaccumulation index (I geo ), pollution load index (PLI), and potential ecological risk index (PERI) were calculated using different background values. Three geochemical (average metal concentrations in continental crust, average metal concentrations in shale, and average metal concentrations in non-contaminated core sediment samples) and two statistical methods (delineation method and principal component analyses) were used for calculating background values. It can be concluded that obtained information of pollution status can be more dependent on the use of background values than the index/factor chosen. The best option to assess the potential river sediment contamination is to compare obtained concentrations of analyzed elements with concentrations of mineralogically and texturally comparable, uncontaminated core sediment samples. Geochemical background values should be taken into account when establishing quality criteria for soils, sediments, and waters. Due to complexity of the local lithology, it is recommended that environmental monitoring and assessment include selection of an appropriate background values to gain understanding of the geochemistry and potential source of pollution in a given environment.

Optimized Deposition Parameters & Coating Properties of Cobalt Phosphorus Alloy Electroplating for Technology Insertion Risk Reduction

DTIC Science & Technology

2010-10-01

of tensile yield strength (Fty) and the runout load (107 cycles), with no more than four points per load. Load and cycles to failure were used to...were coated with 0.002” nCo-P at Integran Technologies Inc. or 0.002” at FRC-SE. Testing was conducted using CS-17 wheels at FRC-SE. 3.2 RESULTS...Abrasive wear tests shall be conducted using the Taber wear test apparatus in accordance with ASTM D4060 using a CS-17 wheel . The wear rate of

Distribution and transport of sediment-bound metal contaminants in the rio grande de tarcoles, costa rica (Central America)

USGS Publications Warehouse

Fuller, C.C.; Davis, J.A.; Cain, D.J.; Lamothe, P.J.; Fries Fernandez, T.L.G.; Vargas, J.A.; Murillo, M.M.

1990-01-01

A reconnaissance survey of the extent of metal contamination in the Rio Grande de Tarcoles river system of Costa Rica indicated high levels of chromium (Cr) in the fine-grain bed sediments (83 times Cr background or 3000->5000 ??g/g). In the main channel of the river downstream of the San Jose urban area, Cr contamination in sediments was 4-6 times background and remained relatively constant over 50 km to the mouth of the river. Sediment from a mangrove swamp at the river mouth had Cr levels 2-3 times above background. Similar patterns of dilution were observed for lead (Pb) and zinc (Zn) sediment contamination, although the contamination levels were lower. The high affinity of Cr towards particulate phases, probably as Cr(III), allows the use of Cr contamination levels for delineating regions of deposition of fine-grained sediments and dilution of particle associated contaminants during transport and deposition.A reconnaissance survey of the extent of metal contamination in the Rio Grande de Tarcoles river system of Costa Rica indicated high levels of chromium (Cr) in the fine-grain bed sediments (83 times Cr background or 3000->5000 ??g/g). In the main channel of the river downstream of the San Jose urban area, Cr contamination in sediments was 4-6 times background and remained relatively constant over 50 km to the mouth of the river. Sediments from a mangrove swamp at the river mouth had Cr levels 2-3 times above background. Similar patterns of dilution were observed for lead (Pb) and zinc (Zn) sediment contamination, although the contamination levels were lower. The high affinity of Cr towards particulate phases, probably as Cr(III), allows the use of Cr contamination levels for delineating regions of deposition of fine-grained sediments and dilution of particle associated contaminants during transport and deposition.

Resolution Versus Error for Computational Electron Microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luzi, Lorenzo; Stevens, Andrew; Yang, Hao

Images that are collected via scanning transmission electron microscopy (STEM) can be undersampled to avoid damage to the specimen while maintaining resolution [1, 2]. We have used BPFA to impute missing data and reduce noise [3]. The reconstruction is typically evaluated using the peak signal-to-noise ratio (PSNR). This measure is too conservative for STEM images and we propose that the Fourier ring correlation (FRC) is used instead to evaluate the reconstruction. We are not concerned with exact reconstruction of the truth image, and therefore PSNR is a conservative estimation of the quality of the reconstruction. Instead, we are concerned withmore » the visual resolution of the image and whether atoms can be distinguished. We have evaluated the reconstruction of a simulated STEM image using the FRC and compared the results with the PSNR measurements. The FRC captures the resolution of the image and is not affected by a large MSE if the atom peaks are still distinguishable. The noisy and reconstructed images are shown in Figure 1. The simulated STEM image was sampled at 100%, 80%, 40%, and 20% of the original pixels to simulate an undersampled scan. The reconstruction was done using BPFA with a patch size of 10 x 10 and no overlapping patches. Not having overlapping patches produces inferior results but they are still acceptable. The dictionary size is 64 and 30 iterations were completed during each reconstruction. The 100% image was denoised instead of reconstructed. Poisson noise was applied to the simulated image with λ values of 500, 50, and 5 to simulate lower imaging dose. The original simulated STEM image was also included in our calculations and was generated using a dose of 1000. The simulated STEM image is 100 by 100 pixels and has essentially no high frequency components. The image reconstruction tends to smooth the data, also resulting in no high frequency components. This causes the FRC of the two images to be large at higher resolutions and may be misleading. For this reason, the BPFA has no overlap to avoid excessive smoothing. Moreover, the resolution of the simulated image is approximately 9.2 (1/nm), so we only look that far in the frequency domain when performing FRC. If the FRC curve does not crossover the threshold, a resolution value of 9.2 is used. We emphasize that our reported results are conservative. The FRC and PSNR values using the ground truth and the reconstructed images are shown in Tables 1 and 2. The left side show the metrics without using BPFA (missing pixels) and the right side show the metrics after using BPFA. When we did not use BPFA, the Fourier transform was estimated [4]. Some threshold curves have been studied [5], but they are derived for additive noise models. Since we have a Poisson noise model, we have used the more conservative threshold of 0.5 for our calculations. Ten images were used to construct each cell of tables in the form of the mean of the metric plus or minus its standard deviation. As expected, the PSNR dies off much quicker than the FRC values for the same image. For the 100% and 80% sampled versions of the truth image, the resolution only dies off when the dose is 5. However, the PSNR dies off rapidly as the dose is reduced. For the 1000, 500, and 50 dose images, the FRC is the maximum, or close, until we undersample at 20%. The PSNR for these values tapers down as we get into the bottom right hand corner of the table, even though the resolution remains high. Overall, we find that undersampled images can be reconstructed to acceptable resolution even when the dose per pixel is also reduced[6]. References: [1]A Stevens, H Yang, L Carin et al. Microscopy 63(1), (2014), pp. 41. [2]A Stevens, L Kovarik, P Abellan et al. Advanced Structural and Chemical Imaging 1(1), (2015), pp. 1. [3]M Zhou, H Chen, J Paisley et al. Image Processing, IEEE Transactions on 21(1), (2012), pp. 130. [4]V. Y. Liepin’sh. Automatic control and computer sciences 30(3), (1996), pp. 20.« less

Inductively Driven, 3D Liner Compression of a Magnetized Plasma to Megabar Energy Densities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slough, John

To take advantage of the smaller scale, higher density regime of fusion an efficient method for achieving the compressional heating required to reach fusion gain conditions must be found. What is proposed is a more flexible metallic liner compression scheme that minimizes the kinetic energy required to reach fusion. It is believed that it is possible to accomplish this at sub-megajoule energies. This however will require operation at very small scale. To have a realistic hope of inexpensive, repetitive operation, it is essential to have the liner kinetic energy under a megajoule which allows for the survivability of the vacuummore » and power systems. At small scale the implosion speed must be reasonably fast to maintain the magnetized plasma (FRC) equilibrium during compression. For limited liner kinetic energy, it becomes clear that the thinnest liner imploded to the smallest radius consistent with the requirements for FRC equilibrium lifetime is desired. The proposed work is directed toward accomplishing this goal. Typically an axial (Z) current is employed for liner compression. There are however several advantages to using a θ-pinch coil. With the θ-pinch the liner currents are inductively driven which greatly simplifies the apparatus and vacuum system, and avoids difficulties with the post implosion vacuum integrity. With fractional flux leakage, the foil liner automatically provides for the seed axial compression field. To achieve it with optimal switching techniques, and at an accelerated pace however will require additional funding. This extra expense is well justified as the compression technique that will be enabled by this funding is unique in the ability to implode individual segments of the liner at different times. This is highly advantageous as the liner can be imploded in a manner that maximizes the energy transfer to the FRC. Production of shaped liner implosions for additional axial compression can thus be readily accomplished with the modified power modules. The additional energy and switching capability proposed will thus provide for optimal utilization of the liner energy. The following tasks were outlined for the three year effort: (1) Design and assemble the foil liner compression test structure and chamber including the compression bank and test foils [Year 1]. (2) Perform foil liner compression experiments and obtain performance data over a range on liner dimensions and bank parameters [Year 2]. (3) Carry out compression experiments of the FRC plasma to Megagauss fields and measure key fusion parameters [Year 3]. (4) Develop numerical codes and analyze experimental results, and determine the physics and scaling for future work [Year 1-3]. The principle task of the project was to design and assemble the foil liner FRC formation chamber, the full compression test structure and chamber including the compression bank. This task was completed successfully. The second task was to test foils in the test facility constructed in year one and characterize the performance obtained from liner compression. These experimental measurements were then compared with analytical predictions, and numerical code results. The liner testing was completed and compared with both the analytical results as well as the code work performed with the 3D structural dynamics package of ANSYS Metaphysics®. This code is capable of modeling the dynamic behavior of materials well into the non-linear regime (e.g. a bullet hit plate glass). The liner dynamic behavior was found to be remarkably close to that predicted by the 3D structural dynamics results. Incorporating a code that can also include the magnetics and plasma physics has also made significant progress at the UW. The remaining test bed construction and assembly task is was completed, and the FRC formation and merging experiments were carried out as planned. The liner compression of the FRC to Megagauss fields was not performed due to not obtaining a sufficiently long lived FRC during the final year of the grant. Modifications planned to correct this deficiency included a larger FRC source as well as a much larger liner driver energy storage system. Due to discontinuation of the grant neither of these improvements were carried out.« less

Kinetic simulation of edge instability in fusion plasmas

NASA Astrophysics Data System (ADS)

Fulton, Daniel Patrick

In this work, gyrokinetic simulations in edge plasmas of both tokamaks and field reversed. configurations (FRC) have been carried out using the Gyrokinetic Toroidal Code (GTC) and A New Code (ANC) has been formulated for cross-separatrix FRC simulation. In the tokamak edge, turbulent transport in the pedestal of an H-mode DIII-D plasma is. studied via simulations of electrostatic driftwaves. Annulus geometry is used and simulations focus on two radial locations corresponding to the pedestal top with mild pressure gradient and steep pressure gradient. A reactive trapped electron instability with typical ballooning mode structure is excited in the pedestal top. At the steep gradient, the electrostatic instability exhibits unusual mode structure, peaking at poloidal angles theta=+- pi/2. Simulations find this unusual mode structure is due to steep pressure gradients in the pedestal but not due to the particular DIII-D magnetic geometry. Realistic DIII-D geometry has a stabilizing effect compared to a simple circular tokamak geometry. Driftwave instability in FRC is studied for the first time using gyrokinetic simulation. GTC. is upgraded to treat realistic equilibrium calculated by an MHD equilibrium code. Electrostatic local simulations in outer closed flux surfaces find ion-scale modes are stable due to the large ion gyroradius and that electron drift-interchange modes are excited by electron temperature gradient and bad magnetic curvature. In the scrape-off layer (SOL) ion-scale modes are excited by density gradient and bad curvature. Collisions have weak effects on instabilities both in the core and SOL. Simulation results are consistent with density fluctuation measurements in the C-2 experiment using Doppler backscattering (DBS). The critical density gradients measured by the DBS qualitatively agree with the linear instability threshold calculated by GTC simulations. One outstanding critical issue in the FRC is the interplay between turbulence in the FRC. core and SOL regions. While the magnetic flux coordinates used by GTC provide a number of computational advantages, they present unique challenges at the magnetic field separatrix. To address this limitation, a new code, capable of coupled core-SOL simulations, is formulated, implemented, and successfully verified.

Identifying decreased diaphragmatic mobility and diaphragm thickening in interstitial lung disease: the utility of ultrasound imaging

PubMed Central

Santana, Pauliane Vieira; Prina, Elena; Albuquerque, André Luis Pereira; Carvalho, Carlos Roberto Ribeiro; Caruso, Pedro

2016-01-01

Objective: To investigate the applicability of ultrasound imaging of the diaphragm in interstitial lung disease (ILD). Methods: Using ultrasound, we compared ILD patients and healthy volunteers (controls) in terms of diaphragmatic mobility during quiet and deep breathing; diaphragm thickness at functional residual capacity (FRC) and at total lung capacity (TLC); and the thickening fraction (TF, proportional diaphragm thickening from FRC to TLC). We also evaluated correlations between diaphragmatic dysfunction and lung function variables. Results: Between the ILD patients (n = 40) and the controls (n = 16), mean diaphragmatic mobility was comparable during quiet breathing, although it was significantly lower in the patients during deep breathing (4.5 ± 1.7 cm vs. 7.6 ± 1.4 cm; p < 0.01). The patients showed greater diaphragm thickness at FRC (p = 0.05), although, due to lower diaphragm thickness at TLC, they also showed a lower TF (p < 0.01). The FVC as a percentage of the predicted value (FVC%) correlated with diaphragmatic mobility (r = 0.73; p < 0.01), and an FVC% cut-off value of < 60% presented high sensitivity (92%) and specificity (81%) for indentifying decreased diaphragmatic mobility. Conclusions: Using ultrasound, we were able to show that diaphragmatic mobility and the TF were lower in ILD patients than in healthy controls, despite the greater diaphragm thickness at FRC in the former. Diaphragmatic mobility correlated with ILD functional severity, and an FVC% cut-off value of < 60% was found to be highly accurate for indentifying diaphragmatic dysfunction on ultrasound. PMID:27167428

Characterizing functional lung heterogeneity in COPD using reference equations for CT scan-measured lobar volumes.

PubMed

Come, Carolyn E; Diaz, Alejandro A; Curran-Everett, Douglas; Muralidhar, Nivedita; Hersh, Craig P; Zach, Jordan A; Schroeder, Joyce; Lynch, David A; Celli, Bartolome; Washko, George R

2013-06-01

CT scanning is increasingly used to characterize COPD. Although it is possible to obtain CT scan-measured lung lobe volumes, normal ranges remain unknown. Using COPDGene data, we developed reference equations for lobar volumes at maximal inflation (total lung capacity [TLC]) and relaxed exhalation (approximating functional residual capacity [FRC]). Linear regression was used to develop race-specific (non-Hispanic white [NHW], African American) reference equations for lobar volumes. Covariates included height and sex. Models were developed in a derivation cohort of 469 subjects with normal pulmonary function and validated in 546 similar subjects. These cohorts were combined to produce final prediction equations, which were applied to 2,191 subjects with old GOLD (Global Initiative for Chronic Obstructive Lung Disease) stage II to IV COPD. In the derivation cohort, women had smaller lobar volumes than men. Height positively correlated with lobar volumes. Adjusting for height, NHWs had larger total lung and lobar volumes at TLC than African Americans; at FRC, NHWs only had larger lower lobes. Age and weight had no effect on lobar volumes at TLC but had small effects at FRC. In subjects with COPD at TLC, upper lobes exceeded 100% of predicted values in GOLD II disease; lower lobes were only inflated to this degree in subjects with GOLD IV disease. At FRC, gas trapping was severe irrespective of disease severity and appeared uniform across the lobes. Reference equations for lobar volumes may be useful in assessing regional lung dysfunction and how it changes in response to pharmacologic therapies and surgical or endoscopic lung volume reduction.

Differential Substrate Specificity and Kinetic Behavior of Escherichia coli YfdW and Oxalobacter formigenes Formyl Coenzyme A Transferase▿ †

PubMed Central

Toyota, Cory G.; Berthold, Catrine L.; Gruez, Arnaud; Jónsson, Stefán; Lindqvist, Ylva; Cambillau, Christian; Richards, Nigel G. J.

2008-01-01

The yfdXWUVE operon appears to encode proteins that enhance the ability of Escherichia coli MG1655 to survive under acidic conditions. Although the molecular mechanisms underlying this phenotypic behavior remain to be elucidated, findings from structural genomic studies have shown that the structure of YfdW, the protein encoded by the yfdW gene, is homologous to that of the enzyme that mediates oxalate catabolism in the obligate anaerobe Oxalobacter formigenes, O. formigenes formyl coenzyme A transferase (FRC). We now report the first detailed examination of the steady-state kinetic behavior and substrate specificity of recombinant, wild-type YfdW. Our studies confirm that YfdW is a formyl coenzyme A (formyl-CoA) transferase, and YfdW appears to be more stringent than the corresponding enzyme (FRC) in Oxalobacter in employing formyl-CoA and oxalate as substrates. We also report the effects of replacing Trp-48 in the FRC active site with the glutamine residue that occupies an equivalent position in the E. coli protein. The results of these experiments show that Trp-48 precludes oxalate binding to a site that mediates substrate inhibition for YfdW. In addition, the replacement of Trp-48 by Gln-48 yields an FRC variant for which oxalate-dependent substrate inhibition is modified to resemble that seen for YfdW. Our findings illustrate the utility of structural homology in assigning enzyme function and raise the question of whether oxalate catabolism takes place in E. coli upon the up-regulation of the yfdXWUVE operon under acidic conditions. PMID:18245280

Type 1 Interferons and NK Cells Limit Murine Cytomegalovirus Escape from the Lymph Node Subcapsular Sinus

PubMed Central

Bruce, Kimberley; Lawler, Clara; Cardin, Rhonda D.

2016-01-01

Cytomegaloviruses (CMVs) establish chronic, systemic infections. Peripheral infection spreads via lymph nodes, which are also a focus of host defence. Thus, this is a point at which systemic infection spread might be restricted. Subcapsular sinus macrophages (SSM) captured murine CMV (MCMV) from the afferent lymph and poorly supported its replication. Blocking the type I interferon (IFN-I) receptor (IFNAR) increased MCMV infection of SSM and of the fibroblastic reticular cells (FRC) lining the subcapsular sinus, and accelerated viral spread to the spleen. Little splenic virus derived from SSM, arguing that they mainly induce an anti-viral state in the otherwise susceptible FRC. NK cells also limited infection, killing infected FRC and causing tissue damage. They acted independently of IFN-I, as IFNAR blockade increased NK cell recruitment, and NK cell depletion increased infection in IFNAR-blocked mice. Thus SSM restricted MCMV infection primarily though IFN-I, with NK cells providing a second line of defence. The capacity of innate immunity to restrict MCMV escape from the subcapsular sinus suggested that enhancing its recruitment might improve infection control. PMID:27926941

Recent breakthroughs on C-2U: Norman’s legacy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Binderbauer, M. W.; Tajima, T.; Tuszewski, M.

Conventional field-reversed configurations (FRC) face notable stability and confinement concerns, which can be ameliorated by introducing and maintaining a significant fast ion population in the system. This is the conjecture first introduced by Norman Rostoker multiple decades ago and adopted as the central design tenet in Tri Alpha Energy’s advanced beam driven FRC concept. In fact, studying the physics of such neutral beam (NB) driven FRCs over the past decade, considerable improvements were made in confinement and stability. Next to NB injection, the addition of axially streaming plasma guns, magnetic end plugs, as well as advanced surface conditioning lead tomore » dramatic reductions in turbulence driven losses and greatly improved stability. In turn, fast ion confinement improved significantly and allowed for the build-up of a dominant fast particle population. This recently led to the breakthrough of sustaining an advanced beam driven FRC, thereby demonstrating successful maintenance of trapped magnetic flux, plasma dimensions and total pressure inventory for times much longer than all characteristic system time scales and only limited by hardware and electric supply constraints.« less

A Pre-ionization System to Limit Neutral Gas in a Compact Toroid Injector

NASA Astrophysics Data System (ADS)

Allfrey, Ian; Roche, Thomas; Matsumoto, Tadafumi; Garate, Eusebio; Gota, Hiroshi; Asai, Tomohiko; the TAE Team

2016-10-01

Fusion plasmas require long lifetimes and high temperatures, both of which are limited by particle loss, among other factors. Therefore, refueling a long-lived advanced beam-driven field-reversed configuration (FRC) plasma in C-2U is necessary, and injecting a supersonic compact toroid (CT) is an effective means of introducing particles into the FRC core. However, neutral gas that trails the CT into the target chamber cools the FRC. Pre-ionization (PI) system assists the break down between electrodes of the CT injector (CTI), so the amount of introduced gas can be lowered by up to a factor of two, effectively increasing the ionization fraction; thus, reducing the amount of neutral gas in the system. Additionally, the PI decreases the delay in CTI breakdown so a highly reproducible operation is achievable. The PI system consists of a fast, high voltage, pulse discharge circuit coupled to a Teflon insulated semi-rigid coaxial cable inserted into the CTI. System details and experimental data will be presented, in addition to issues such as the introduction of impurities and pre-ionizer lifetime.

Lung volumes during sustained microgravity on Spacelab SLS-1

NASA Technical Reports Server (NTRS)

Elliott, Ann R.; Prisk, Gordon Kim; Guy, Harold J. B.; West, John B.

1994-01-01

Gravity is known to influence the topographical gradients of pulmonary ventilation, perfusion, and pleural pressures. The effect of sustained microgravity on lung volumes has not previously been investigated. Pulmonary function tests were performed by four subjects before, during, and after 9 days of microgravity exposure. Ground measurements were made in standing and supine postures. Tests were performed using a bag-in-box and flowmeter system and a respiratory mass spectrometer. Measurements of tidal volume (V(sub T)), expiratory reserve volume (ERV), inspiratory and expiratory vital capacities (IVC, EVC), functional residual capacity (FRC), and residual volume (RV) were made. During microgravity, V(sub T) decreased by 15%. IVC and EVC were slightly reduced during the first 24 hrs of microgravity and returned to 1 g standing values within 72 hrs after the onset of microgravity. FRC was reduced by 15% and ERV decreased by 10-20%. RV was significantly reduced by 18%. The reductions in FRC, ERV, and V(sub T) during microgravity are probably due to the cranial shift of the diaphragm and an increase in intrathoracic blood volume.

Tissue Engineering of Cartilage on Ground-Based Facilities

NASA Astrophysics Data System (ADS)

Aleshcheva, Ganna; Bauer, Johann; Hemmersbach, Ruth; Egli, Marcel; Wehland, Markus; Grimm, Daniela

2016-06-01

Investigations under simulated microgravity offer the opportunity for a better understanding of the influence of altered gravity on cells and the scaffold-free three-dimensional (3D) tissue formation. To investigate the short-term influence, human chondrocytes were cultivated for 2 h, 4 h, 16 h, and 24 h on a 2D Fast-Rotating Clinostat (FRC) in DMEM/F-12 medium supplemented with 10 % FCS. We detected holes in the vimentin network, perinuclear accumulations of vimentin after 2 h, and changes in the chondrocytes shape visualised by F-actin staining after 4 h of FRC-exposure. Scaffold-free cultivation of chondrocytes for 7 d on the Random Positioning Machine (RPM), the FRC and the Rotating Wall Vessel (RWV) resulted in spheroid formation, a phenomenon already known from spaceflight experiments with chondrocytes (MIR Space Station) and thyroid cancer cells (SimBox/Shenzhou-8 space mission). The experiments enabled by the ESA-CORA-GBF programme gave us an optimal opportunity to study gravity-related cellular processes, validate ground-based facilities for our chosen cell system, and prepare long-term experiments under real microgravity conditions in space

Whole Device Modeling of Compact Tori: Stability and Transport Modeling of C-2W

NASA Astrophysics Data System (ADS)

Dettrick, Sean; Fulton, Daniel; Lau, Calvin; Lin, Zhihong; Ceccherini, Francesco; Galeotti, Laura; Gupta, Sangeeta; Onofri, Marco; Tajima, Toshiki; TAE Team

2017-10-01

Recent experimental evidence from the C-2U FRC experiment shows that the confinement of energy improves with inverse collisionality, similar to other high beta toroidal devices, NSTX and MAST. This motivated the construction of a new FRC experiment, C-2W, to study the energy confinement scaling at higher electron temperature. Tri Alpha Energy is working towards catalysing a community-wide collaboration to develop a Whole Device Model (WDM) of Compact Tori. One application of the WDM is the study of stability and transport properties of C-2W using two particle-in-cell codes, ANC and FPIC. These codes can be used to find new stable operating points, and to make predictions of the turbulent transport at those points. They will be used in collaboration with the C-2W experimental program to validate the codes against C-2W, mitigate experimental risk inherent in the exploration of new parameter regimes, accelerate the optimization of experimental operating scenarios, and to find operating points for future FRC reactor designs.

Fragmented red cells reference range for the Sysmex XN®-series of automated blood cell counters.

PubMed

Lesesve, J-F; Speyer, E; Perol, J-P

2015-10-01

Fragmented red cells (FRCs) are a new parameter determined automatically by the latest generation of blood cell counters. FRC counts may be of interest as they may reflect schistocyte counts measured on a stained peripheral blood smear observed under the microscope. However, FRC counts depend on the technical procedure used to detect them so that reference ranges are device dependent. The XN-9000® is one of the latest models from the Sysmex series of analysers. We aimed to establish a reference range for FRCs based on 1366 normal patient samples. The mean ± SD was 0.14 ± 0.35% and the median was 0% (95% confidence interval of the mean: 0.12-0.16%). We observed that the percentage of red blood cells with <17 pg of haemoglobin content (Hypo-He) was correlated to an FRC increase and that flagged results relating to red blood cells, reticulocytes or platelets might have presented with artefactually increased FRCs. The FRCs reference range (healthy subjects) should be useful for laboratory staff for selecting which blood smears to check optically. © 2015 John Wiley & Sons Ltd.

Lung volumes: measurement, clinical use, and coding.

PubMed

Flesch, Judd D; Dine, C Jessica

2012-08-01

Measurement of lung volumes is an integral part of complete pulmonary function testing. Some lung volumes can be measured during spirometry; however, measurement of the residual volume (RV), functional residual capacity (FRC), and total lung capacity (TLC) requires special techniques. FRC is typically measured by one of three methods. Body plethysmography uses Boyle's Law to determine lung volumes, whereas inert gas dilution and nitrogen washout use dilution properties of gases. After determination of FRC, expiratory reserve volume and inspiratory vital capacity are measured, which allows the calculation of the RV and TLC. Lung volumes are commonly used for the diagnosis of restriction. In obstructive lung disease, they are used to assess for hyperinflation. Changes in lung volumes can also be seen in a number of other clinical conditions. Reimbursement for measurement of lung volumes requires knowledge of current procedural terminology (CPT) codes, relevant indications, and an appropriate level of physician supervision. Because of recent efforts to eliminate payment inefficiencies, the 10 previous CPT codes for lung volumes, airway resistance, and diffusing capacity have been bundled into four new CPT codes.

Multi-layer porous fiber-reinforced composites for implants: in vitro calcium phosphate formation in the presence of bioactive glass.

PubMed

Nganga, Sara; Zhang, Di; Moritz, Niko; Vallittu, Pekka K; Hupa, Leena

2012-11-01

Glass-fiber-reinforced composites (FRCs), based on bifunctional methacrylate resin, have recently shown their potential for use as durable cranioplasty, orthopedic and oral implants. In this study we suggest a multi-component sandwich implant structure with (i) outer layers out of porous FRC, which interface the cortical bone, and (ii) inner layers encompassing bioactive glass granules, which interface with the cancellous bone. The capability of Bioglass(®) 45S5 granules (100-250μm) to induce calcium phosphate formation on the surface of the FRC was explored by immersing the porous FRC-Bioglass laminates in simulated body fluid (SBF) for up to 28d. In both static (agitated) and dynamic conditions, bioactive glass granules induced precipitation of calcium phosphate at the laminate surfaces as confirmed by scanning electron microscopy. The proposed dynamic flow system is useful for the in vitro simulation of bone-like apatite formation on various new porous implant designs containing bioactive glass and implant material degradation. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Fiber-reinforced composite fixed dental prostheses: two clinical reports.

PubMed

Zarow, Maciej; Paisley, Carl Stuart; Krupinski, Jerzy; Brunton, Paul Anthony

2010-06-01

Various options are available in clinical practice for the replacement of a single missing tooth, ranging from conventional fixed and removable dental prostheses to a single implant-supported crown. There are situations in which a semipermanent fixed dental prosthesis may be desirable, particularly for patients who have completed orthodontic treatment but are too young to embark on implant therapy. Following advances in fiber-reinforcement technology, fiber-reinforced composite resin (FRC) now represents a lower-cost alternative to traditional metal-ceramic for the construction of resin-bonded prostheses. Two case reports illustrate the use of FRC prostheses as fixed semipermanent_restorations.

M2-F3 on lakebed

NASA Image and Video Library

1970-06-20

The M2-F3 Lifting Body is seen here on the lakebed next to the NASA Flight Research Center (FRC--later Dryden Flight Research Center), Edwards, California. The May 1967 crash of the M2-F2 had torn off the left fin and landing gear. It had also damaged the external skin and internal structure. Flight Research Center engineers worked with Ames Research Center and the Air Force in redesigning the vehicle with a center fin to provide greater stability. Then Northrop Corporation cooperated with the FRC in rebuilding the vehicle. The entire process took three years.

Apportionment of polycyclic aromatic hydrocarbon sources in lower Fox River, USA, sediments by a chemical mass balance model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, M.C.; Christensen, E.R.; Karls, J.F.

Four sediment cores were collected from the lower Fox River, Wisconsin, USA, to identify possible sources of polycyclic aromatic hydrocarbons (PAHs) using a chemical mass balance model. The cores, which were obtained in 1995 from areas close to Green Bay, Wisconsin, USA, had total PAH concentrations between 19.3 and 0.34 ppm. To determine historical trends of PAH inputs, {sup 210}Pb and {sup 137}Cs dating was used, and elemental carbon particle analysis was done to characterize particles from the combustion of coal, wood, and petroleum. Source fingerprints were taken from the literature. Their results indicate that coke oven emissions, highway dust,more » coal gasification, and wood burning are likely sources of PAHs in the lower Fox River. Coke oven emissions are in the range of 40 to 90% of total PAHs, and this fraction decreases from 1930 to 1990, except in core Fox River-A (FR-A). The overall highway dust (HWY) contribution is between 10 and 75%, and this fraction increases from 1930 to present, except in core FR-A. The wood burning (WB) contribution is less than 7% in cores FR-B, FR-C, and FR-D. In core FR-A, a maximum ({approximately}23%) is found around 1960. The contribution of wood burning has changed from less than 6% in 1950 to between 3 and 10% in 1995. Evidence of aerobic biodegradation or photolysis in the sediment of phenanthrene, with a half-life of approximately 0.5 years has been found at the site of core FR-D, which is the shallowest (1.1 m) of the four core sites.« less

The effect of high fiber fraction on some mechanical properties of unidirectional glass fiber-reinforced composite.

PubMed

Abdulmajeed, Aous A; Närhi, Timo O; Vallittu, Pekka K; Lassila, Lippo V

2011-04-01

This study was designed to evaluate the effect of an increase of fiber-density on some mechanical properties of higher volume fiber-reinforced composite (FRC). Five groups of FRC with increased fiber-density were fabricated and two additional groups were prepared by adding silanated barium-silicate glass fillers (0.7 μm) to the FRC. The unidirectional E-glass fiber rovings were impregnated with light-polymerizable bisGMA-TEGDMA (50-50%) resin. The fibers were pulled through a cylindrical mold with an opening diameter of 4.2mm, light cured for 40s and post-cured at elevated temperature. The cylindrical specimens (n=12) were conditioned at room temperature for 2 days before testing with the three-point bending test (Lloyd Instruments Ltd.) adapted to ISO 10477. Fiber-density was analyzed by combustion and gravimetric analyzes. ANOVA analysis revealed that by increasing the vol.% fraction of E-glass fibers from 51.7% to 61.7% there was a change of 27% (p<0.05) in the modulus of elasticity, 34% (p<0.05) in the toughness, and 15% (p<0.05) in the load bearing capacity, while there was only 8% (p<0.05) increase in the flexural strength although it was statistically insignificant. The addition of particulate fillers did not improve the mechanical properties. This study showed that the properties of FRC could be improved by increasing fibervolume fraction. Modulus of elasticity, toughness, and load bearing capacity seem to follow the law of ratio of quantity of fibers and volume of the polymer matrix more precisely than flexural strength when high fiber-density is used. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

MicroCT analysis of a retrieved root restored with a bonded fiber-reinforced composite dowel: a pilot study.

PubMed

Lorenzoni, Fabio Cesar; Bonfante, Estevam A; Bonfante, Gerson; Martins, Leandro M; Witek, Lukasz; Silva, Nelson R F A

2013-08-01

This evaluation aimed to (1) validate micro-computed tomography (microCT) findings using scanning electron microscopy (SEM) imaging, and (2) quantify the volume of voids and the bonded surface area resulting from fiber-reinforced composite (FRC) dowel cementation technique using microCT scanning technology/3D reconstructing software. A fiberglass dowel was cemented in a condemned maxillary lateral incisor prior to its extraction. A microCT scan was performed of the extracted tooth creating a large volume of data in DICOM format. This set of images was imported to image-processing software to inspect the internal architecture of structures. The outer surface and the spatial relationship of dentin, FRC dowel, cement layer, and voids were reconstructed. Three-dimensional spatial architecture of structures and volumetric analysis revealed that 9.89% of the resin cement was composed of voids and that the bonded area between root dentin and cement was 60.63% larger than that between cement and FRC dowel. SEM imaging demonstrated the presence of voids similarly observed using microCT technology (aim 1). MicroCT technology was able to nondestructively measure the volume of voids within the cement layer and the bonded surface area at the root/cement/FRC interfaces (aim 2). The interfaces at the root dentin/cement/dowel represent a timely and relevant topic where several efforts have been conducted in the past few years to understand their inherent features. MicroCT technology combined with 3D reconstruction allows for not only inspecting the internal arrangement rendered by fiberglass adhesively bonded to root dentin, but also estimating the volume of voids and contacted bond area between the dentin and cement layer. © 2013 by the American College of Prosthodontists.

Evaluation of the effect of a home-bleaching agent on the surface characteristics of indirect esthetic restorative materials: part I--roughness.

PubMed

Torabi, Kianoosh; Rasaeipour, Sasan; Khaledi, Amir Alireza; Vojdani, Mahroo; Ghodsi, Safoura

2014-05-01

Pressing esthetic demands of good looking make people undergo bleaching procedures. However, the effect of bleaching agents on esthetic restorative materials with different surface preparations has been poorly studied. The aim of this study was to examine the effect of a homebleaching agent (carbamide peroxide: CP 38%) on the surface roughness of the polished fiber reinforced composite (FRC), overglazed, autoglazed, or polished ceramic samples. Twenty standardized cylindrical specimens were made of each of the following groups: over-glazed, autoglazed, polished porcelain and also FRC. The test specimens exposed to the CP 38%, 15 minutes, twice a day for 2 weeks according to the manufacturer's recommendation. Six samples from each group were selected randomly to form negative controls. Surface roughness measurements (Ra, micrometer) for baseline, test and control specimens were performed by use of a profilometer. Paired t-test, Mann-Whitney test, and Kruskal-Wallis test were used for statistical analyses. The data showed that bleaching with CP 38% significantly increased the surface roughness of all the test samples (p < 0.05). The type of surface preparation caused significant differences between the susceptibility of porcelain subgroups to bleaching (p < 0.05). The polished porcelain specimens showed the highest changes after bleaching. CP 38% significantly increases the surface roughness of the porcelains and FRC. The type of surface condition affects the amenability of the porcelain surface to the bleaching agent. Glazed porcelains were more resistant to roughness than the polished porcelains and also the composite. Roughening of porcelain and FRC occur following bleaching procedure. No special surface preparation of indirect esthetic restorative materials can completely preserve these materials from adverse effects of bleaching agents.

Dynamic loop gain increases upon adopting the supine body position during sleep in patients with obstructive sleep apnoea.

PubMed

Joosten, Simon A; Landry, Shane A; Sands, Scott A; Terrill, Philip I; Mann, Dwayne; Andara, Christopher; Skuza, Elizabeth; Turton, Anthony; Berger, Philip; Hamilton, Garun S; Edwards, Bradley A

2017-11-01

Obstructive sleep apnoea (OSA) is typically worse in the supine versus lateral sleeping position. One potential factor driving this observation is a decrease in lung volume in the supine position which is expected by theory to increase a key OSA pathogenic factor: dynamic ventilatory control instability (i.e. loop gain). We aimed to quantify dynamic loop gain in OSA patients in the lateral and supine positions, and to explore the relationship between change in dynamic loop gain and change in lung volume with position. Data from 20 patients enrolled in previous studies on the effect of body position on OSA pathogenesis were retrospectively analysed. Dynamic loop gain was calculated from routinely collected polysomnographic signals using a previously validated mathematical model. Lung volumes were measured in the awake state with a nitrogen washout technique. Dynamic loop gain was significantly higher in the supine than in the lateral position (0.77 ± 0.15 vs 0.68 ± 0.14, P = 0.012). Supine functional residual capacity (FRC) was significantly lower than lateral FRC (81.0 ± 15.4% vs 87.3 ± 18.4% of the seated FRC, P = 0.021). The reduced FRC we observed on moving to the supine position was predicted by theory to increase loop gain by 10.2 (0.6, 17.1)%, a value similar to the observed increase of 8.4 (-1.5, 31.0)%. Dynamic loop gain increased by a small but statistically significant amount when moving from the lateral to supine position and this may, in part, contribute to the worsening of OSA in the supine sleeping position. © 2017 Asian Pacific Society of Respirology.

Advanced Fuels Reactor using Aneutronic Rodless Ultra Low Aspect Ratio Tokamak Hydrogenic Plasmas

NASA Astrophysics Data System (ADS)

Ribeiro, Celso

2015-11-01

The use of advanced fuels for fusion reactor is conventionally envisaged for field reversed configuration (FRC) devices. It is proposed here a preliminary study about the use of these fuels but on an aneutronic Rodless Ultra Low Aspect Ratio (RULART) hydrogenic plasmas. The idea is to inject micro-size boron pellets vertically at the inboard side (HFS, where TF is very high and the tokamak electron temperature is relatively low because of profile), synchronised with a proton NBI pointed to this region. Therefore, p-B reactions should occur and alpha particles produced. These pellets will act as an edge-like disturbance only (cp. killer pellet, although the vertical HFS should make this less critical, since the unablated part should appear in the bottom of the device). The boron cloud will appear at midplance, possibly as a MARFE-look like. Scaling of the p-B reactions by varying the NBI energy should be compared with the predictions of nuclear physics. This could be an alternative to the FRC approach, without the difficulties of the optimization of the FRC low confinement time. Instead, a robust good tokamak confinement with high local HFS TF (enhanced due to the ultra low aspect ratio and low pitch angle) is used. The plasma central post makes the RULART concept attractive because of the proximity of NBI path and also because a fraction of born alphas will cross the plasma post and dragged into it in the direction of the central plasma post current, escaping vertically into a hole in the bias plate and reaching the direct electricity converter, such as in the FRC concept.

Novel methodology to perform sulfur hexafluoride (SF6)-based multiple-breath wash-in and washout in infants using current commercially available equipment.

PubMed

Gustafsson, P M; Robinson, P D; Lindblad, A; Oberli, D

2016-11-01

Multiple-breath inert gas washout (MBW) is ideally suited for early detection and monitoring of serious lung disease, such as cystic fibrosis, in infants and young children. Validated commercial options for the MBW technique are limited, and suitability of nitrogen (N 2 )-based MBW is of concern given the detrimental effect of exposure to pure O 2 on infant breathing pattern. We propose novel methodology using commercially available N 2 MBW equipment to facilitate 4% sulfur hexafluoride (SF 6 ) multiple-breath inert gas wash-in and washout suitable for the infant age range. CO 2 , O 2 , and sidestream molar mass sensor signals were used to accurately calculate SF 6 concentrations. An improved dynamic method for synchronization of gas and respiratory flow was developed to take into account variations in sidestream sample flow during MBW measurement. In vitro validation of triplicate functional residual capacity (FRC) assessments was undertaken under dry ambient conditions using lung models ranging from 90 to 267 ml, with tidal volumes of 28-79 ml, and respiratory rates 20-60 per minute. The relative mean (SD, 95% confidence interval) error of triplicate FRC determinations by washout was -0.26 (1.84, -3.86 to +3.35)% and by wash-in was 0.57 (2.66, -4.66 to +5.79)%. The standard deviations [mean (SD)] of percentage error among FRC triplicates were 1.40 (1.14) and 1.38 (1.32) for washout and wash-in, respectively. The novel methodology presented achieved FRC accuracy as outlined by current MBW consensus recommendations (95% of measurements within 5% accuracy). Further clinical evaluation is required, but this new technique, using existing commercially available equipment, has exciting potential for research and clinical use. Copyright © 2016 the American Physiological Society.

Palmitate attenuates osteoblast differentiation of fetal rat calvarial cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeh, Lee-Chuan C.; Ford, Jeffery J.; Lee, John C.

Highlights: • Palmitate inhibits osteoblast differentiation. • Fatty acid synthase. • PPARγ. • Acetyl Co-A carboxylase inhibitor TOFA. • Fetal rat calvarial cell culture. - Abstract: Aging is associated with the accumulation of ectopic lipid resulting in the inhibition of normal organ function, a phenomenon known as lipotoxicity. Within the bone marrow microenvironment, elevation in fatty acid levels may produce an increase in osteoclast activity and a decrease in osteoblast number and function, thus contributing to age-related osteoporosis. However, little is known about lipotoxic mechanisms in intramembraneous bone. Previously we reported that the long chain saturated fatty acid palmitate inhibitedmore » the expression of the osteogenic markers RUNX2 and osteocalcin in fetal rat calvarial cell (FRC) cultures. Moreover, the acetyl CoA carboxylase inhibitor TOFA blocked the inhibitory effect of palmitate on expression of these two markers. In the current study we have extended these observations to show that palmitate inhibits spontaneous mineralized bone formation in FRC cultures in association with reduced mRNA expression of RUNX2, alkaline phosphatase, osteocalcin, and bone sialoprotein and reduced alkaline phosphatase activity. The effects of palmitate on osteogenic marker expression were inhibited by TOFA. Palmitate also inhibited the mRNA expression of fatty acid synthase and PPARγ in FRC cultures, and as with osteogenic markers, this effect was inhibited by TOFA. Palmitate had no effect on FRC cell proliferation or apoptosis, but inhibited BMP-7-induced alkaline phosphatase activity. We conclude that palmitate accumulation may lead to lipotoxic effects on osteoblast differentiation and mineralization and that increases in fatty acid oxidation may help to prevent these lipotoxic effects.« less

Effect of Cementation Technique of Individually Formed Fiber-Reinforced Composite Post on Bond Strength and Microleakage

PubMed Central

Makarewicz, Dominika; Le Bell-Rönnlöf, Anna-Maria B; Lassila, Lippo V.J.; Vallittu, Pekka K.

2013-01-01

Objectives: The aim of this study was to evaluate the effect of two different cementation techniques of individually formed E-glass fiber-reinforced composite (FRC) post on bond strength and microleakage. Methods: The crowns of extracted third molars were removed and post preparation was carried out with parapost drills (diameter 1.5 mm). After application of bonding agents individually formed FRC posts (everStick POST, diameter 1.5 mm) were cemented into the post spaces with either ParaCem®Universal or self-adhesive RelyX™Unicem, using two different cementation techniques: 1) an “indirect (traditional) technique” where the post was prepolymerized prior application of luting cement and insertion into the post space or 2) a “direct technique” where the uncured post was inserted to the post space with luting cement and light-polymerized in situ at the same time. After water storage of 48 hours, the roots (n = 10/group) were cut into discs of thickness of 2 mm. A push-out force was applied until specimen fracture or loosening of the post. A microleakage test was carried out on roots which were not subjected to the loading test (n= 32) to evaluate the sealing capacity of the post-canal interface. The microleakage was measured using dye penetration depth under a stereomicroscope. Results: Higher bond strength values (p<0.05) and less microleakage (p<0.05) were obtained with the “direct technique” compared to the “indirect technique”. None of the FRC posts revealed any dye penetration between the post and the cement. Conclusions: The “direct technique” seems to be beneficial when cementing individually formed FRC posts. PMID:23986792

Static lung volumes in healthy subjects assessed by helium dilution during occlusion of one mainstem bronchus.

PubMed

Johansen, B; Bjørtuft, O; Boe, J

1993-04-01

Single lung function is usually assessed by radioisotopes or, more rarely, by bronchospirometry in which a double lumen catheter is used to separate ventilation of the two lungs. The latter is more precise but less comfortable. An alternative bronchoscopic method is described for determining the volume of a single lung. One mainstem bronchus was temporarily occluded with an inflatable balloon during fibreoptic bronchoscopy in 12 healthy volunteers aged 18-29 years. The functional residual capacities (FRC) of the right, left, and both lungs were measured in duplicate by closed circuit helium dilution. Supplementary vital capacity (VC) manoeuvres permitted calculation of single lung capacities (TLC) and residual volumes (RV). The standard deviation of a single determination of capacities of the right, left, and both lungs were: TLC, 80, 96, and 308 ml; VC, 56, 139, 171 ml; FRC, 131, 74, and 287 ml; RV, 112, 185, and 303 ml, respectively. The sum of the right and left unilateral TLC was not different from bilateral TLC (6.12 v 5.95 l) and the sum of the unilateral FRC was not different from the bilateral FRC (2.60 v 2.78 l). The sum of the unilateral VC was lower than bilateral VC (4.52 v 4.80 l), that of the unilateral RV was higher than bilateral RV (1.60 v 1.16 l). For all subdivisions of lung volume, the right lung was larger than the left. The most common complaint was substernal discomfort during complete exhalation. Oxygen saturation rarely fell below 90%. Temporary occlusion of a mainstem bronchus in normal subjects is safe, relatively simple, and allows fairly precise and accurate measurements of unilateral static lung volumes. Occlusion at TLC, however, probably prevents proper emptying of the non-occluded lung.

Lethal and Sublethal Effects on Tamarixia triozae (Hymenoptera: Eulophidae), an Ectoparasitoid of Bactericera cockerelli (Hemiptera: Triozidae), of Three Insecticides Used on Solanaceous Crops.

PubMed

Morales, Sinue I; Martínez, Ana M; Viñuela, Elisa; Chavarrieta, Juan M; Figueroa, José I; Schneider, Marcela I; Tamayo, Fernando; Pineda, Samuel

2018-05-28

Lethal and sublethal effects of refined soybean oil, imidacloprid, and abamectin on Tamarixia triozae (Burks; Hymenoptera: Eulophidae) were assessed after exposure of the eggs, larvae, and pupae of this parasitoid to three concentrations of these active substances: the LC50 for fourth-instar Bactericera cockerelli (Sulc.; Hemiptera: Triozidae) and 50% and 100% of the minimum field-registered concentration (MiFRC). Soybean oil caused 26-61% mortality in T. triozae eggs and 6-19% in larvae; mortality in both eggs and larvae was ≤19% for imidacloprid and 4-100% for abamectin. All three compounds caused <18% mortality of T. triozae pupae, with the exception of the abamectin 50% (47%) and 100% (72%) MiFRC. The mortality of larvae and pupae derived from treated eggs was ≤39% for all three insecticides, and that of pupae derived from treated larvae was ≤10%. In general, emergence of adults developed from treated eggs, larvae, and pupae was affected more by abamectin than by the other treatments. The proportion of females derived from all three development stages was not affected by treatment with the compounds, except when the parasitoid was treated as larvae with the soybean oil 100 and 50% MiFRC (66 and 68%, respectively) or when treated as pupae with the imidacloprid LC50 and 100% MiFRC (~60%). Female longevity was generally higher than that of males. The use of imidacloprid, soybean oil, and abamectin in combination with T. triozae for pest control may be effective when the parasitoid is in the pupal stage because this stage is less susceptible than other immature stages.

Determination of premining geochemical background and delineation of extent of sediment contamination in Blue Creek downstream from Midnite Mine, Stevens County, Washington

USGS Publications Warehouse

Church, Stan E.; Kirschner, Frederick E.; Choate, LaDonna M.; Lamothe, Paul J.; Budahn, James R.; Brown, Zoe Ann

2008-01-01

Geochemical and radionuclide studies of sediment recovered from eight core sites in the Blue Creek flood plain and Blue Creek delta downstream in Lake Roosevelt provided a stratigraphic geochemical record of the contamination from uranium mining at the Midnite Mine. Sediment recovered from cores in a wetland immediately downstream from the mine site as well as from sediment catchments in Blue Creek and from cores in the delta in Blue Creek cove provided sufficient data to determine the premining geochemical background for the Midnite Mine tributary drainage. These data provide a geochemical background that includes material eroded from the Midnite Mine site prior to mine development. Premining geochemical background for the Blue Creek basin has also been determined using stream-sediment samples from parts of the Blue Creek, Oyachen Creek, and Sand Creek drainage basins not immediately impacted by mining. Sediment geochemistry showed that premining uranium concentrations in the Midnite Mine tributary immediately downstream of the mine site were strongly elevated relative to the crustal abundance of uranium (2.3 ppm). Cesium-137 (137Cs) data and public records of production at the Midnite Mine site provided age control to document timelines in the sediment from the core immediately downstream from the mine site. Mining at the Midnite Mine site on the Spokane Indian Reservation between 1956 and 1981 resulted in production of more than 10 million pounds of U3O8. Contamination of the sediment by uranium during the mining period is documented from the Midnite Mine along a small tributary to the confluence of Blue Creek, in Blue Creek, and into the Blue Creek delta. During the period of active mining (1956?1981), enrichment of base metals in the sediment of Blue Creek delta was elevated by as much as 4 times the concentration of those same metals prior to mining. Cadmium concentrations were elevated by a factor of 10 and uranium by factors of 16 to 55 times premining geochemical background determined upstream of the mine site. Postmining metal concentrations in sediment are lower than during the mining period, but remain elevated relative to premining geochemical background. Furthermore, the sediment composition of surface sediment in the Blue Creek delta is contaminated. Base-metal contamination by arsenic, cadmium, lead, and zinc in sediment in the delta in Blue Creek cove is dominated by suspended sediment from the Coeur d?Alene mining district. Uranium contamination in surface sediment in the delta of Blue Creek cove extends at least 500 meters downstream from the mouth of Blue Creek as defined by the 1,290-ft elevation boundary between lands administered by the National Park Service and the Spokane Indian Tribe. Comparisons of the premining geochemical background to sediment sampled during the period the mine was in operation, and to the sediment data from the postmining period, are used to delineate the extent of contaminated sediment in Blue Creek cove along the thalweg of Blue Creek into Lake Roosevelt. The extent of contamination out into Lake Roosevelt by mining remains open.

Local lung deposition of ultrafine particles in healthy adults: experimental results and theoretical predictions

PubMed Central

2016-01-01

Background Ultrafine particles (UFP) of biogenic and anthropogenic origin occur in high numbers in the ambient atmosphere. In addition, aerosols containing ultrafine powders are used for the inhalation therapy of various diseases. All these facts make it necessary to obtain comprehensive knowledge regarding the exact behavior of UFP in the respiratory tract. Methods Theoretical simulations of local UFP deposition are based on previously conducted inhalation experiments, where particles with various sizes (0.04, 0.06, 0.08, and 0.10 µm) were administered to the respiratory tract by application of the aerosol bolus technique. By the sequential change of the lung penetration depth of the inspired bolus, different volumetric lung regions could be generated and particle deposition in these regions could be evaluated. The model presented in this contribution adopted all parameters used in the experiments. Besides the obligatory comparison between practical and theoretical data, also advanced modeling predictions including the effect of varying functional residual capacity (FRC) and respiratory flow rate were conducted. Results Validation of the UFP deposition model shows that highest deposition fractions occur in those volumetric lung regions corresponding to the small and partly alveolated airways of the tracheobronchial tree. Particle deposition proximal to the trachea is increased in female probands with respect to male subjects. Decrease of both the FRC and the respiratory flow rate results in an enhancement of UFP deposition. Conclusions The study comes to the conclusion that deposition of UFP taken up via bolus inhalation is influenced by a multitude of factors, among which lung morphometry and breathing conditions play a superior role. PMID:27942511

Commercial D-T FRC Power Plant Systems Analysis

NASA Astrophysics Data System (ADS)

Nguyen, Canh; Santarius, John; Emmert, Gilbert; Steinhauer, Loren; Stubna, Michael

1998-11-01

Results of an engineering issues scoping study of a Field-Reversed Configuration (FRC) burning D-T fuel will be presented. The study primarily focuses on engineering issues, such as tritium-breeding blanket design, radiation shielding, neutron damage, activation, safety, and environment. This presentation will concentrate on plasma physics, current drive, economics, and systems integration, which are important for the overall systems analysis. A systems code serves as the key tool in defining a reference point for detailed physics and engineering calculations plus parametric variations, and typical cases will be presented. Advantages of the cylindrical geometry and high beta (plasma pressure/magnetic-field pressure) are evident.

M2-F3 on lakebed

NASA Image and Video Library

1970-06-19

The M2-F3 Lifting Body is seen here on the lakebed at the NASA Flight Research Center (FRC--later the Dryden Flight Research Center), Edwards, California. After a three-year-long redesign and rebuilding effort, the M2-F3 was ready to fly. The May 1967 crash of the M2-F2 had damaged both the external skin and the internal structure of the lifting body. At first, it seemed that the vehicle had been irreparably damaged, but the original manufacturer, Northrop, did the repair work and returned the redesigned M2-F3 with a center fin for stability to the FRC.

Overview of C-2W Field-Reversed Configuration Experimental Program

NASA Astrophysics Data System (ADS)

Gota, H.; Binderbauer, M. W.; Tajima, T.; Putvinski, S.; Tuszewski, M.; Dettrick, S.; Korepanov, S.; Romero, J.; Smirnov, A.; Song, Y.; Thompson, M. C.; van Drie, A.; Yang, X.; Ivanov, A. A.; TAE Team

2017-10-01

Tri Alpha Energy's research has been devoted to producing a high temperature, stable, long-lived field-reversed configuration (FRC) plasma state by neutral-beam injection (NBI) and edge biasing/control. C-2U experiments have demonstrated drastic improvements in particle and energy confinement properties of FRC's, and the plasma performance obtained via 10 MW NBI has achieved plasma sustainment of up to 5 ms and plasma (diamagnetism) lifetimes of 10 + ms. The emerging confinement scaling, whereby electron energy confinement time is proportional to a positive power of the electron temperature, is very attractive for higher energy plasma confinement; accordingly, verification of the observed Te scaling law will be a key future research objective. The new experimental device, C-2W (now also called ``Norman''), has the following key subsystem upgrades from C-2U: (i) higher injected power, optimum energies, and extended pulse duration of the NBI system; (ii) installation of inner divertors with upgraded edge-biasing systems; (iii) fast external equilibrium/mirror-coil current ramp-up capability; and (iv) installation of trim/saddle coils for active feedback control of the FRC plasma. This paper will review highlights of the C-2W program.

Rehabilitation of a periodontal patient with rapidly progressing marginal alveolar bone loss: 1-year follow-up.

PubMed

Sewón, L A; Ampula, L; Vallittu, P K

2000-08-01

The present case report describes a 1-year follow-up of functional rehabilitation of a young periodontal patient with severely advanced, rapidly progressing marginal bone loss treated by using a new splinting material, i.e., glass fiber-reinforced composite (FRC). Apart from one single tooth, the young man had retained all his natural teeth. Periodontal treatment was based on cleaning and root planing enabled by partial-thickness-flap operations. This method was selected to avoid further damage to the remaining alveolar bone. After healing for 6 months, a cavity retained internal FRC splint was constructed and 1 missing lower molar was replaced by an inlay-retained FRC resin-bonded fixed partial denture (FPD). A 12 months follow-up period revealed a healthy periodontium and good functional and esthetic results. The new material allows the use of periodontal treatment methods instead of prosthetic alternatives, which until now have been a more generally used approach in the treatment of severely advanced periodontal cases. Internal fiber-reinforced composite splinting being affordable for the patient, easy for the clinician to construct and giving good esthetic and functional results, suggests that the method may be a valuable aid in periodontal treatment.

Two-dimensional interpreter for field-reversed configurations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steinhauer, Loren, E-mail: lstein@uw.edu

2014-08-15

An interpretive method is developed for extracting details of the fully two-dimensional (2D) “internal” structure of field-reversed configurations (FRC) from common diagnostics. The challenge is that only external and “gross” diagnostics are routinely available in FRC experiments. Inferring such critical quantities as the poloidal flux and the particle inventory has commonly relied on a theoretical construct based on a quasi-one-dimensional approximation. Such inferences sometimes differ markedly from the more accurate, fully 2D reconstructions of equilibria. An interpreter based on a fully 2D reconstruction is needed to enable realistic within-the-shot tracking of evolving equilibrium properties. Presented here is a flexible equilibriummore » reconstruction with which an extensive data base of equilibria was constructed. An automated interpreter then uses this data base as a look-up table to extract evolving properties. This tool is applied to data from the FRC facility at Tri Alpha Energy. It yields surprising results at several points, such as the inferences that the local β (plasma pressure/external magnetic pressure) of the plasma climbs well above unity and the poloidal flux loss time is somewhat longer than previously thought, both of which arise from full two-dimensionality of FRCs.« less

Simulations of High Harmonic Fast Wave Heating on the C-2U Advanced Beam-Driven Field-Reversed Configuration Device

NASA Astrophysics Data System (ADS)

Yang, Xiaokang; Petrov, Yuri; Ceccherini, Francesco; Koehn, Alf; Galeotti, Laura; Dettrick, Sean; Binderbauer, Michl

2017-10-01

Numerous efforts have been made at Tri-Alpha Energy (TAE) to theoretically explore the physics of microwave electron heating in field-reversed configuration (FRC) plasmas. For the fixed 2D profiles of plasma density and temperature for both electrons and thermal ions and equilibrium field of the C-2U machine, simulations with GENRAY-C ray-tracing code have been conducted for the ratios of ω/ωci[D] in the range of 6 - 20. Launch angles and antenna radial and axial positions have been optimized in order to simultaneously achieve good wave penetration into the core of FRC plasmas and efficient power damping on electrons. It is found that in an optimal regime, single pass absorption efficiency is 100% and most of the power is deposited inside the separatrix of FRC plasmas, with power damping efficiency of about 72% on electrons and less than 19% on ions. Calculations have clearly demonstrated that substantial power absorption on electrons is mainly attributed to high beta enhancement of magnetic pumping; complete power damping occurs before Landau damping has a significant effect on power absorption.

UEDGE Simulations for Power and Particle Flow Analysis of FRC Rocket

NASA Astrophysics Data System (ADS)

Zheng, Fred; Evans, Eugene S.; McGreivy, Nick; Kaptanoglu, Alan; Izacard, Olivier; Cohen, Samuel A.

2017-10-01

The field-reversed configuration (FRC) is under consideration for use in a direct fusion drive (DFD) rocket propulsion system for future space missions. To achieve a rocket configuration, the FRC is embedded within an asymmetric magnetic mirror, in which one end is closed and contains a gas box, and the other end is open and incorporates a magnetic nozzle. Neutral deuterium is injected into the gas box, and flows through the scrape-off layer (SOL) around the core plasma and out the magnetic nozzle, both cooling the core and serving as propellant. Previous studies have examined a range of operating conditions for the SOL of a DFD using UEDGE, a 2D fluid code; discrepancies on the order of 5% were found during the analysis of overall power balance. This work extends the analysis of the previously-studied SOL geometry by updating boundary conditions and conducting a detailed study of power and particle flows within the simulation with the goals of modeling electrical power generation instead of thrust and achieving higher specific impulse. This work was supported, in part, by DOE Contract Number DE-AC02-09CH11466 and Princeton Environmental Institute.

Probe measurements of the three-dimensional magnetic field structure in a rotating magnetic field sustained field-reversed configuration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Velas, K. M.; Milroy, R. D.

A translatable three-axis probe was constructed and installed on the translation, confinement, and sustainment upgrade (TCSU) experiment. With ninety windings, the probe can simultaneously measure B{sub r}, B{sub θ}, and B{sub z} at 30 radial positions, and can be placed at any desired axial position within the field reversed configuration (FRC) confinement chamber. Positioning the probe at multiple axial positions and taking multiple repeatable shots allows for a full r-z map of the magnetic field. Measurements were made for odd-parity rotating magnetic field (RMF) antennas and even-parity RMF. The steady state data from applying a 10 kHz low pass filter usedmore » in conjunction with data at the RMF frequency yields a map of the full 3D rotating field structure. Comparisons will be made to the 3D magnetic structure predicted by NIMROD simulations, with parameters adjusted to match that of the TCSU experiments. The probe provides sufficient data to utilize a Maxwell stress tensor approach to directly measure the torque applied to the FRC's electrons, which combined with a resistive torque model, yields an estimate of the average FRC resistivity.« less

Are conventional statistical techniques exhaustive for defining metal background concentrations in harbour sediments? A case study: The Coastal Area of Bari (Southeast Italy).

PubMed

Mali, Matilda; Dell'Anna, Maria Michela; Mastrorilli, Piero; Damiani, Leonardo; Ungaro, Nicola; Belviso, Claudia; Fiore, Saverio

2015-11-01

Sediment contamination by metals poses significant risks to coastal ecosystems and is considered to be problematic for dredging operations. The determination of the background values of metal and metalloid distribution based on site-specific variability is fundamental in assessing pollution levels in harbour sediments. The novelty of the present work consists of addressing the scope and limitation of analysing port sediments through the use of conventional statistical techniques (such as: linear regression analysis, construction of cumulative frequency curves and the iterative 2σ technique), that are commonly employed for assessing Regional Geochemical Background (RGB) values in coastal sediments. This study ascertained that although the tout court use of such techniques in determining the RGB values in harbour sediments seems appropriate (the chemical-physical parameters of port sediments fit well with statistical equations), it should nevertheless be avoided because it may be misleading and can mask key aspects of the study area that can only be revealed by further investigations, such as mineralogical and multivariate statistical analyses. Copyright © 2015 Elsevier Ltd. All rights reserved.

Environmental background values of trace elements in sediments from the Jiaozhou Bay catchment, Qingdao, China.

PubMed

Xu, Fangjian; Liu, Zhaoqing; Yuan, Shengqiang; Zhang, Xilin; Sun, Zhilei; Xu, Feng; Jiang, Zuzhou; Li, Anchun; Yin, Xuebo

2017-08-15

Selected trace elements (As, Cr, Zn, Cu, Cd, Co, Pb and Ni) in 76 surface sediment samples collected from the rivers and the intertidal zone of Jiaozhou Bay (JZB) were evaluated to assess their environmental background values in the JZB catchment. Overall, the sediment quality in the area meets the China Marine Sediment Quality criteria. The background values (ranges) of the elements As, Cr, Zn, Cu, Cd, Co, Pb and Ni were, respectively, 8.28 (4.10-12.46), 67.96 (38.40-97.52), 56.80 (16.42-196.51), 19.13 (5.71-64.06), 0.10 (0.02-0.42), 6.51 (2.08-20.40), 17.97 (12.26-55.84) and 20.69 (10.43-30.95)mg/kg. The background values of most of the trace elements were lower than those in Chinese soil, the upper continental crust, global shales and global preindustrial sediments. The results may assist in defining future coastal and river management measures specifically targeted at monitoring trace element contamination in the JZB catchment. Copyright © 2017 Elsevier Ltd. All rights reserved.

The relationship between fibre post geometry and flexural properties: an assessment through a modified three-point bending test.

PubMed

Soares, L P; de Vasconcellos, A B; da Silva, A H Monteiro da Fonseca Thomé; Sampaio, E M; Vianna, G A de Deus Carneiro

2010-12-01

The aim of this study was to investigate the flexural properties of five types of fiber-reinforced dowels using a modified three-point bending test. Fiber-reinforced resin dowels were tested by a modified three-point bending test associated with models for cylindrical and conical simple-supported beams. The fracture load ranged from 86 to 246 N and the flexural strength from 423 to 1192 MPa. FRC Postec had significantly higher flexural strength and fracture loads values. Thus, the present study demonstrated higher flexural strength values for the FRC Postec fibre posts, suggesting that this system would present a better response to the forces of mastication.

10Be constrains the sediment sources and sediment yields to the Great Barrier Reef from the tropical Barron River catchment, Queensland, Australia

NASA Astrophysics Data System (ADS)

Nichols, K. K.; Bierman, P. R.; Rood, D. H.

2014-12-01

Estimates of long-term, background sediment generation rates place current and future sediment fluxes to the Great Barrier Reef in context. Without reliable estimates of sediment generation rates and without identification of the sources of sediment delivered to the reef prior to European settlement (c. 1850), determining the necessity and effectiveness of contemporary landscape management efforts is difficult. Using the ~2100-km2 Barron River catchment in Queensland, Australia, as a test case, we use in situ-produced 10Be to derive sediment generation rate estimates and use in situ and meteoric 10Be to identify the source of that sediment, which enters the Coral Sea near Cairns. Previous model-based calculations suggested that background sediment yields were up to an order of magnitude lower than contemporary sediment yields. In contrast, in situ 10Be data indicate that background (43 t km-2 y-1) and contemporary sediment yields (~45 t km-2 y-1) for the Barron River are similar. These data suggest that the reef became established in a sediment flux similar to what it receives today. Since western agricultural practices increased erosion rates, large amounts of sediment mobilized from hillslopes during the last century are probably stored in Queensland catchments and will eventually be transported to the coast, most likely in flows triggered by rare but powerful tropical cyclones that were more common before European settlement and may increase in strength as climate change warms the south Pacific Ocean. In situ and meteoric 10Be concentrations of Coral Sea beach sand near Cairns are similar to those in rivers on the Atherton Tablelands, suggesting that most sediment is derived from the extensive, low-gradient uplands rather than the steep, more rapidly eroding but beach proximal escarpment.

3D-WOVEN FIBER-REINFORCED COMPOSITE FOR CAD/CAM DENTAL APPLICATION

PubMed Central

Petersen, Richard; Liu, Perng-Ru

2016-01-01

Three-dimensional (3D)-woven noncrimp fiber-reinforced composite (FRC) was tested for mechanical properties in the two principal directions of the main XY plane and compared to different Computer-Aided-Design/Computer-Aided-Machining (CAD/CAM) Dental Materials. The Dental Materials included ceramic with Vitablock Mark II®, ProCAD®, InCeram® Spinel, InCeram® Alumina and InCeram® Zirconia in addition to a resin-based 3M Corp. Paradigm® particulate-filled composite. Alternate material controls included Coors 300 Alumina Ceramic and a tungsten carbide 22% cobalt cermet. The 3D-woven FRC was vacuum assisted resin transfer molding processed as a one-depth-thickness ~19-mm preform with a vinyl-ester resin and cut into blocks similar to the commercial CAD/CAM Dental Materials. Mechanical test samples prepared for a flexural three-point span length of 10.0 mm were sectioned for minimum-depth cuts to compare machinability and fracture resistance between groups. 3D-woven FRC improved mechanical properties with significant statistical differences over all CAD/CAM Dental Materials and Coors Alumina Ceramic for flexural strength (p<0.001), resilience (p<0.05), work of fracture (p<0.001), strain energy release (p<0.05), critical stress intensity factor (p<0.001) and strain (p<0.001). PMID:27642198

Time dependent changes of material properties of FRC due to intensive heating

NASA Astrophysics Data System (ADS)

Prochazka, Petr P.

2014-02-01

Studies on porous media, particularly on fiber-reinforced concrete (FRC), which is exposed to various temperature conditions, are of great concern for engineers and researchers in wide scale of civil and underground construction. The problem consists in a relatively very complicated description of processes which the concrete undergoes during the change of loading conditions, such as change of temperature (fire), wetting, moistening, attack by chemical substances, etc. There are too many variables which should be observed and their mutual effect should be taken into consideration. If a structure is loaded by a change of temperature on one boundary surface, a texture of the concrete varies and the phases inside the concrete adopt the temperature conditions. In this paper, a numerical study based on 3D finite elements, and an experimental one based on the effect of various conditions of temperature, degree of saturation of gaseous and water parts in pores and vapor are carried out. The parameters in the numerical study are tuned according to the results from the experiments. The theory is established based on thermodynamic laws, Fourier's law, Fick's law, balance conditions, etc. An immediate application of the results from this paper is in underground structures, mainly in concrete (FRC) linings of tunnels. More general applications are much wider.

Effect of different intraorifice barriers on the fracture resistance of roots obturated with Resilon or gutta-percha.

PubMed

Nagas, Emre; Uyanik, Ozgur; Altundasar, Emre; Durmaz, Veli; Cehreli, Zafer C; Vallittu, Pekka K; Lassila, Lippo V J

2010-06-01

This study investigated and compared the root reinforcement potential of 3 different intraorifice barriers (mineral trioxide aggregate [MTA], resin-modified glass ionomer cement [Vitremer], and fiber-reinforced composite [FRC]) placed over root canals obturated with gutta-percha or Resilon. Crowns of 80 extracted human mandibular premolars were sectioned off to obtain 14-mm-long root specimens. After preparation of root canals with nickel-titanium rotary files, the roots were obturated with either the Resilon/Epiphany system or gutta-percha + AH Plus sealer. In both obturation groups, specimens were further subgrouped with respect to the intraorifice barrier material placed after removal of 3-mm coronal portion of the root fillings: (1) MTA, (2) Vitremer, and (3) FRC. The specimens were loaded vertically at 1 mm/min crosshead speed until vertical root fracture occurred. Results were evaluated statistically with two-way analysis of variance and Tukey tests. Fracture resistance of roots was significantly affected by the type of intraorifice barrier (P < .05), but not by the type of obturation system used (P > .05). The use of Vitremer and FRC significantly improved the fracture resistance, whereas MTA did not exhibit any reinforcing effect as an intraorifice barrier. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

3D-WOVEN FIBER-REINFORCED COMPOSITE FOR CAD/CAM DENTAL APPLICATION.

PubMed

Petersen, Richard; Liu, Perng-Ru

2016-05-01

Three-dimensional (3D)-woven noncrimp fiber-reinforced composite (FRC) was tested for mechanical properties in the two principal directions of the main XY plane and compared to different Computer-Aided-Design/Computer-Aided-Machining (CAD/CAM) Dental Materials. The Dental Materials included ceramic with Vitablock Mark II®, ProCAD®, InCeram® Spinel, InCeram® Alumina and InCeram® Zirconia in addition to a resin-based 3M Corp. Paradigm® particulate-filled composite. Alternate material controls included Coors 300 Alumina Ceramic and a tungsten carbide 22% cobalt cermet. The 3D-woven FRC was vacuum assisted resin transfer molding processed as a one-depth-thickness ~19-mm preform with a vinyl-ester resin and cut into blocks similar to the commercial CAD/CAM Dental Materials. Mechanical test samples prepared for a flexural three-point span length of 10.0 mm were sectioned for minimum-depth cuts to compare machinability and fracture resistance between groups. 3D-woven FRC improved mechanical properties with significant statistical differences over all CAD/CAM Dental Materials and Coors Alumina Ceramic for flexural strength (p<0.001), resilience (p<0.05), work of fracture (p<0.001), strain energy release (p<0.05), critical stress intensity factor (p<0.001) and strain (p<0.001).

Predicting critical micelle concentration and micelle molecular weight of polysorbate 80 using compendial methods.

PubMed

Braun, Alexandra C; Ilko, David; Merget, Benjamin; Gieseler, Henning; Germershaus, Oliver; Holzgrabe, Ulrike; Meinel, Lorenz

2015-08-01

This manuscript addresses the capability of compendial methods in controlling polysorbate 80 (PS80) functionality. Based on the analysis of sixteen batches, functionality related characteristics (FRC) including critical micelle concentration (CMC), cloud point, hydrophilic-lipophilic balance (HLB) value and micelle molecular weight were correlated to chemical composition including fatty acids before and after hydrolysis, content of non-esterified polyethylene glycols and sorbitan polyethoxylates, sorbitan- and isosorbide polyethoxylate fatty acid mono- and diesters, polyoxyethylene diesters, and peroxide values. Batches from some suppliers had a high variability in functionality related characteristic (FRC), questioning the ability of the current monograph in controlling these. Interestingly, the combined use of the input parameters oleic acid content and peroxide value - both of which being monographed methods - resulted in a model adequately predicting CMC. Confining the batches to those complying with specifications for peroxide value proved oleic acid content alone as being predictive for CMC. Similarly, a four parameter model based on chemical analyses alone was instrumental in predicting the molecular weight of PS80 micelles. Improved models based on analytical outcome from fingerprint analyses are also presented. A road map controlling PS80 batches with respect to FRC and based on chemical analyses alone is provided for the formulator. Copyright © 2014 Elsevier B.V. All rights reserved.

Screening of soy protein-derived hypotriglyceridemic di-peptides in vitro and in vivo

PubMed Central

2011-01-01

Background Soy protein and soy peptides have attracted considerable attention because of their potentially beneficial biological properties, including antihypertensive, anticarcinogenic, and hypolipidemic effects. Although soy protein isolate contains several bioactive peptides that have distinct physiological activities in lipid metabolism, it is not clear which peptide sequences are responsible for the triglyceride (TG)-lowering effects. In the present study, we investigated the effects of soy protein-derived peptides on lipid metabolism, especially TG metabolism, in HepG2 cells and obese Otsuka Long-Evans Tokushima fatty (OLETF) rats. Results In the first experiment, we found that soy crude peptide (SCP)-LD3, which was prepared by hydrolyze of soy protein isolate with endo-type protease, showed hypolipidemic effects in HepG2 cells and OLETF rats. In the second experiment, we found that hydrophilic fraction, separated from SCP-LD3 with hydrophobic synthetic absorbent, revealed lipid-lowering effects in HepG2 cells and OLETF rats. In the third experiment, we found that Fraction-C (Frc-C) peptides, fractionated from hydrophilic peptides by gel permeation chromatography-high performance liquid chromatography, significantly reduced TG synthesis and apolipoprotein B (apoB) secretion in HepG2 cells. In the fourth experiment, we found that the fraction with 0.1% trifluoroacetic acid, isolated from Frc-C peptides by octadecylsilyl column chromatography, showed hypolipidemic effects in HepG2 cells. In the final experiment, we found that 3 di-peptides, Lys-Ala, Val-Lys, and Ser-Tyr, reduced TG synthesis, and Ser-Tyr additionally reduced apoB secretion in HepG2 cells. Conclusion Novel active peptides with TG-lowering effects from soy protein have been isolated. PMID:21600040

The Effect of Compartmental Asymmetry on the Monitoring of Pulmonary Mechanics and Lung Volumes.

PubMed

Keenan, Joseph C; Cortes-Puentes, Gustavo A; Adams, Alexander B; Dries, David J; Marini, John J

2016-11-01

Esophageal pressure measurement for computation of transpulmonary pressure (P tp ) has begun to be incorporated into clinical use for evaluating forces across the lungs. Gaps exist in our understanding of how esophageal pressure (and therefore P tp ), a value measured at a single site, responds when respiratory system compartments are asymmetrically affected by whole-lung atelectasis or unilateral injury as well as changes in chest wall compliance. We reasoned that P tp would track with aerated volume changes as estimated by functional residual capacity (FRC) and tidal volume. We examined this hypothesis in the setting of asymmetric lungs and changes in intra-abdominal pressure. This study was conducted in the animal laboratory of a university-affiliated hospital. Models of unilateral atelectasis and unilateral and bilateral lung injury exposed to intra-abdominal hypertension (IAH) in 10 deeply sedated mechanically ventilated swine. Atelectasis was created by balloon occlusion of the left main bronchus. Unilateral lung injury was induced by saline lavage of isolated right lung. Diffuse lung injury was induced by saline lavage of both lungs. The peritoneum was insufflated with air to create a model of pressure-regulated IAH. We measured esophageal pressures, airway pressures, FRC by gas dilution, and oxygenation. FRC was reduced by IAH in normal lungs (P < .001) and both asymmetric lung pathologies (P < .001). P tp at end-expiration was decreased by IAH in bilateral (P = .001) and unilateral lung injury (P = .003) as well as unilateral atelectasis (P = .019). In the setting of both lung injury models, end-expiratory P tp showed a moderate correlation in tracking with FRC. P tp tracks with aerated lung volume in the setting of thoracic asymmetry and changes in intra-abdominal pressure. However, used alone, it cannot distinguish the relative contributions of air-space distention and recruitment of lung units. Copyright © 2016 by Daedalus Enterprises.

THE PHYSICS OF THE FAR-INFRARED-RADIO CORRELATION. I. CALORIMETRY, CONSPIRACY, AND IMPLICATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lacki, Brian C.; Thompson, Todd A.; Quataert, Eliot, E-mail: lacki@astronomy.ohio-state.ed

2010-07-01

The far-infrared (FIR) and radio luminosities of star-forming galaxies are linearly correlated over a very wide range in star formation rate, from normal spirals like the Milky Way to the most intense starbursts. Using one-zone models of cosmic ray (CR) injection, cooling, and escape in star-forming galaxies, we attempt to reproduce the observed FIR-radio correlation (FRC) over its entire span. The normalization and linearity of the FRC, together with constraints on the CR population in the Milky Way, have strong implications for the CR and magnetic energy densities in star-forming galaxies. We show that for consistency with the FRC, {approx}2%more » of the kinetic energy from supernova explosions must go into high-energy primary CR electrons and that {approx}10%-20% must go into high-energy primary CR protons. Secondary electrons and positrons are likely comparable to or dominate primary electrons in dense starburst galaxies. We discuss the implications of our models for the magnetic field strengths of starbursts, the detectability of starbursts by Fermi, and CR feedback. Overall, our models indicate that both CR protons and electrons escape from low surface density galaxies, but lose most of their energy before escaping dense starbursts. The FRC is caused by a combination of the efficient cooling of CR electrons (calorimetry) in starbursts and a conspiracy of several factors. For lower surface density galaxies, the decreasing radio emission caused by CR escape is balanced by the decreasing FIR emission caused by the low effective UV dust opacity. In starbursts, bremsstrahlung, ionization, and inverse Compton cooling decrease the radio emission, but they are countered by secondary electrons/positrons and the dependence of synchrotron frequency on energy, both of which increase the radio emission. Our conclusions hold for a broad range of variations in our fiducial model, such as those including winds, different magnetic field strengths, and different diffusive escape times.« less

Assessment of toxic metal contamination using a regional lithogenic geochemical background, Pampean area river basin, Argentina.

PubMed

Castro, Liliana Norma; Rendina, Alicia Elena; Orgeira, Maria Julia

2018-06-15

Contamination assessment in riverbed sediments depends on the accurate determination of the background values. The aim of this study is to assess the degree of contamination and to evaluate the most adequate background for the determination of anthropogenic contamination in Cd, Cr, Cu, Ni, Pb and Zn in bed sediments of the Pampean area river basin (Matanza-Riachuelo River and tributary streams), Argentina. The geo-accumulation index (Igeo) values were calculated using selected lithogenic backgrounds (loess, loessoid sediments and paleosoils), the metal concentrations in the residual fraction (F4) in riverbed sediments and a global average shale often applied in the estimation of toxic metal Igeo. The IgeoF4, IgeoLZB and most of the others Igeos, indicated that in land areas used mainly for agriculture and cattle grazing, the superficial sediments were uncontaminated with Cd, Cr, Cu and Zn, and slightly contaminated with Ni and Pb. Conversely, in those areas dedicated to urban and industrial use, the metal contamination was greater. Overall, the relatively significant anthropogenic contamination of Cr > Pb ≥ Cu > Zn > Ni > Cd in the Riachuelo River area was associated with metallurgic activities, tanning and industrial waste. The comparative analysis of different values suggested that Buenos Aires' "pristine" loess could be recommended to evaluate the Igeo index of riverbed sediments in the Pampean area. To enhance the use of the selected background, the normalized enrichment factor using Al. In this study case, the Igeo and the EF using LZB background display the same trend, showing the greatest degree of contamination, as would be expected, in Riachuelo samples (RIA 1 and RIA 2) located in the urban/industrial area. Copyright © 2018 Elsevier B.V. All rights reserved.

Characterization of compact-toroid injection during formation, translation, and field penetration

NASA Astrophysics Data System (ADS)

Matsumoto, T.; Roche, T.; Allfrey, I.; Sekiguchi, J.; Asai, T.; Gota, H.; Cordero, M.; Garate, E.; Kinley, J.; Valentine, T.; Waggoner, W.; Binderbauer, M.; Tajima, T.

2016-11-01

We have developed a compact toroid (CT) injector system for particle refueling of the advanced beam-driven C-2U field-reversed configuration (FRC) plasma. The CT injector is a magnetized coaxial plasma gun (MCPG), and the produced CT must cross the perpendicular magnetic field surrounding the FRC for the refueling of C-2U. To simulate this environment, an experimental test stand has been constructed. A transverse magnetic field of ˜1 kG is established, which is comparable to the C-2U axial magnetic field in the confinement section, and CTs are fired across it. On the test stand we have been characterizing and studying CT formation, ejection/translation from the MCPG, and penetration into transverse magnetic fields.

Plasma-gun-assisted field-reversed configuration formation in a conical θ-pinch

NASA Astrophysics Data System (ADS)

Weber, T. E.; Intrator, T. P.; Smith, R. J.

2015-04-01

Injection of plasma via an annular array of coaxial plasma guns during the pre-ionization phase of field-reversed configuration (FRC) formation is shown to catalyze the bulk ionization of a neutral gas prefill in the presence of a strong axial magnetic field and change the character of outward flux flow during field-reversal from a convective process to a much slower resistive diffusion process. This approach has been found to significantly improve FRC formation in a conical θ-pinch, resulting in a ˜350% increase in trapped flux at typical operating conditions, an expansion of accessible formation parameter space to lower densities and higher temperatures, and a reduction or elimination of several deleterious effects associated with the pre-ionization phase.

Characterization of compact-toroid injection during formation, translation, and field penetration.

PubMed

Matsumoto, T; Roche, T; Allfrey, I; Sekiguchi, J; Asai, T; Gota, H; Cordero, M; Garate, E; Kinley, J; Valentine, T; Waggoner, W; Binderbauer, M; Tajima, T

2016-11-01

We have developed a compact toroid (CT) injector system for particle refueling of the advanced beam-driven C-2U field-reversed configuration (FRC) plasma. The CT injector is a magnetized coaxial plasma gun (MCPG), and the produced CT must cross the perpendicular magnetic field surrounding the FRC for the refueling of C-2U. To simulate this environment, an experimental test stand has been constructed. A transverse magnetic field of ∼1 kG is established, which is comparable to the C-2U axial magnetic field in the confinement section, and CTs are fired across it. On the test stand we have been characterizing and studying CT formation, ejection/translation from the MCPG, and penetration into transverse magnetic fields.

Ideal-Magnetohydrodynamic-Stable Tilting in Field-Reversed Configurations

NASA Astrophysics Data System (ADS)

Kanno, Ryutaro; Ishida, Akio; Steinhauer, Loren

1995-02-01

The tilting mode in field-reversed configurations (FRC) is examined using ideal-magnetohydrodynamic stability theory. Tilting, a global mode, is the greatest threat for disruption of FRC confinement. Previous studies uniformly found tilting to be unstable in ideal theory: the objective here is to ascertain if stable equilibria were overlooked in past work. Solving the variational problem with the Rayleigh-Ritz technique, tilting-stable equilibria are found for sufficiently hollow current profile and sufficient racetrackness of the separatrix shape. Although these equilibria were not examined previously, the present conclusion is quite surprising. Consequently checks of the method are offered. Even so it cannot yet be claimed with complete certainty that stability has been proved: absolute confirmation of ideal-stable tilting awaits the application of more complete methods.

Multi-Fluid Simulations of Field Reversed Configuration Formation

NASA Astrophysics Data System (ADS)

Sousa, Eder; Martin, Robert

2017-10-01

The use of field reversed configuration (FRC) have been studied extensively for fusion application but here we investigate them for propulsion purposes. FRCs have the potential to produce highly variable thrust and specific impulse using different gases as propellant. Aspects of the FRC formation physics, using a rotating magnetic field (RMF) at low power, are simulated using a multi-fluid plasma model. Results are compared with experimental observations with emphasis in the development of instabilities and robustness of the field reversal. The use of collisional radiative models are used to help compare experiment versus simulation results. Distribution A: Approved for public release; distribution unlimited; Clearance No. 17445. This work is supported by the Air Force Office of Scientific Research Grant Number 17RQCOR465.

Human land uses enhance sediment denitrification and N2O production in Yangtze lakes primarily by influencing lake water quality

NASA Astrophysics Data System (ADS)

Liu, W.; Yao, L.; Wang, Z.; Xiong, Z.; Liu, G.

2015-10-01

Sediment denitrification in lakes alleviates the effects of eutrophication through the removal of nitrogen to the atmosphere as N2O and N2. However, N2O contributes notably to the greenhouse effect and global warming. Human land uses (e.g. agricultural and urban areas) strongly affect lake water quality and sediment characteristics, which, in turn, may regulate lake sediment denitrification and N2O production. In this study, we investigated sediment denitrification and N2O production and their relationships to within-lake variables and watershed land uses in 20 lakes from the Yangtze River basin in China. The results indicated that both lake water quality and sediment characteristics were significantly influenced by watershed land uses. N2O production rates increased with increasing background denitrification rates. Background denitrification and N2O production rates were positively related to water nitrogen concentrations but were not significantly correlated with sediment characteristics and plant community structure. A significant positive relationship was observed between background denitrification rate and percentage of human-dominated land uses (HDL) in watersheds. Structural equation modelling revealed that the indirect effects of HDL on sediment denitrification and N2O production in Yangtze lakes were mediated primarily through lake water quality. Our findings also suggest that although sediments in Yangtze lakes can remove large quantities of nitrogen through denitrification, they may also be an important source of N2O, especially in lakes with high nitrogen content.

Functional liver image guided hepatic therapy (FLIGHT) with hepatobiliary iminodiacetic acid (HIDA) scans.

PubMed

Long, David E; Tann, Mark; Huang, Ke Colin; Bartlett, Gregory; Galle, James O; Furukawa, Yukie; Maluccio, Mary; Cox, John A; Kong, Feng-Ming Spring; Ellsworth, Susannah G

2018-05-01

Hepatobiliary iminodiacetic acid (HIDA) scans provide global and regional assessments of liver function that can serve as a road map for functional avoidance in stereotactic body radiation therapy (SBRT) planning. Functional liver image guided hepatic therapy (FLIGHT), an innovative planning technique, is described and compared with standard planning using functional dose-volume histograms. Thresholds predicting for decompensation during follow up are evaluated. We studied 17 patients who underwent HIDA scans before SBRT. All SBRT cases were replanned using FLIGHT. The following dosimetric endpoints were compared for FLIGHT versus standard SBRT planning: functional residual capacity <15 Gy (FRC 15 HIDA), mean liver dose (MLD), equivalent uniform dose (EUD), and functional EUD (FEUD). Receiver operating characteristics curves were used to evaluate whether baseline HIDA values, standard cirrhosis scoring, and/or dosimetric data predicted clinical decompensation. Compared with standard planning, FLIGHT significantly improved FRC 15 HIDA (mean improvement: 5.3%) as well as MLD, EUD, and FEUD (P < .05). Considerable interindividual variations in the extent of benefit were noted. Decompensation during follow-up was associated with baseline global HIDA <2.915%/min/m 2 , FRC 15 HIDA <2.11%/min/m 2 , and MELD ≥11 (P < .05). FLIGHT with HIDA-based parameters may complement blood chemistry-based assessments of liver function and facilitate individualized, adaptive liver SBRT planning. Copyright © 2018. Published by Elsevier Inc.

Simulating free-roaming cat population management options in open demographic environments.

PubMed

Miller, Philip S; Boone, John D; Briggs, Joyce R; Lawler, Dennis F; Levy, Julie K; Nutter, Felicia B; Slater, Margaret; Zawistowski, Stephen

2014-01-01

Large populations of free-roaming cats (FRCs) generate ongoing concerns for welfare of both individual animals and populations, for human public health, for viability of native wildlife populations, and for local ecological damage. Managing FRC populations is a complex task, without universal agreement on best practices. Previous analyses that use simulation modeling tools to evaluate alternative management methods have focused on relative efficacy of removal (or trap-return, TR), typically involving euthanasia, and sterilization (or trap-neuter-return, TNR) in demographically isolated populations. We used a stochastic demographic simulation approach to evaluate removal, permanent sterilization, and two postulated methods of temporary contraception for FRC population management. Our models include demographic connectivity to neighboring untreated cat populations through natural dispersal in a metapopulation context across urban and rural landscapes, and also feature abandonment of owned animals. Within population type, a given implementation rate of the TR strategy results in the most rapid rate of population decline and (when populations are isolated) the highest probability of population elimination, followed in order of decreasing efficacy by equivalent rates of implementation of TNR and temporary contraception. Even low levels of demographic connectivity significantly reduce the effectiveness of any management intervention, and continued abandonment is similarly problematic. This is the first demographic simulation analysis to consider the use of temporary contraception and account for the realities of FRC dispersal and owned cat abandonment.

From the Journal archives: Airway closure and lung volumes in surgical positions.

PubMed

Grocott, Hilary P

2014-04-01

Douglas B. Craig, W.M. Wahba, Hillary Don Can Anaesth Soc J 1971; 18: 92-9. Surgery and anesthesia expose patients to moderate and sometimes extreme positioning changes that are often unphysiological. The purpose of this article is to highlight and contextualize a seminal study from the Journal archives that explores the effect of several commonly utilized surgical positions (supine, Trendelenburg and lithotomy) and age on basic lung volumes as well as the volume at which small airway closure (AC) (also known as closing volume [CV]) occurs. These factors were examined with the aim of determining which patient position variables could be of clinical significance to gas exchange in the perioperative period. This work showed that supine positioning, when compared with the seated position, results in a decrease of all lung volumes and capacities, including functional residual capacity (FRC) and CV. Trendelenburg positioning further decreases FRC, with no further changes induced by lithotomy positioning. Age is a clinically important factor in AC, occurring within the tidal volume range at a lower age when supine as compared with the seated position. The work of Drs. D. Craig et al. published in the Journal more than 40 years ago was seminal to our understanding of how patient positioning has an important influence on lung volumes and on the age-related relationship between FRC and CV.

North American Society for Pediatric and Adolescent Gynecology

MedlinePlus

... and Long Curriculum U.S. Medical Eligibility Criteria for Contraceptive Use, 2016 U.S. Selected Practice Recommendations for Contraceptive Use, 2016 NASPAG Fellows Research Consortium (FRC) RENEW ...

Plasma-gun-assisted field-reversed configuration formation in a conical θ-pinch

DOE PAGES

Weber, T. E.; Intrator, T. P.; Smith, R. J.

2015-04-29

We show through injection of plasma via an annular array of coaxial plasma guns, during the pre-ionization phase of field-reversed configuration (FRC) formation how to catalyze the bulk ionization of a neutral gas prefill in the presence of a strong axial magnetic field and change the character of outward flux flow during field-reversal from a convective process to a much slower resistive diffusion process. Our approach has been found to significantly improve FRC formation in a conical θ-pinch, resulting in a ~350% increase in trapped flux at typical operating conditions, an expansion of accessible formation parameter space to lower densitiesmore » and higher temperatures, and a reduction or elimination of several deleterious effects associated with the pre-ionization phase.« less

Plasma-gun-assisted field-reversed configuration formation in a conical θ-pinch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weber, T. E., E-mail: tweber@lanl.gov; Intrator, T. P.; Smith, R. J.

2015-04-15

Injection of plasma via an annular array of coaxial plasma guns during the pre-ionization phase of field-reversed configuration (FRC) formation is shown to catalyze the bulk ionization of a neutral gas prefill in the presence of a strong axial magnetic field and change the character of outward flux flow during field-reversal from a convective process to a much slower resistive diffusion process. This approach has been found to significantly improve FRC formation in a conical θ-pinch, resulting in a ∼350% increase in trapped flux at typical operating conditions, an expansion of accessible formation parameter space to lower densities and highermore » temperatures, and a reduction or elimination of several deleterious effects associated with the pre-ionization phase.« less

Characterization of compact-toroid injection during formation, translation, and field penetration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsumoto, T., E-mail: cstd14003@g.nihon-u.ac.jp; Sekiguchi, J.; Asai, T.

2016-11-15

We have developed a compact toroid (CT) injector system for particle refueling of the advanced beam-driven C-2U field-reversed configuration (FRC) plasma. The CT injector is a magnetized coaxial plasma gun (MCPG), and the produced CT must cross the perpendicular magnetic field surrounding the FRC for the refueling of C-2U. To simulate this environment, an experimental test stand has been constructed. A transverse magnetic field of ∼1 kG is established, which is comparable to the C-2U axial magnetic field in the confinement section, and CTs are fired across it. On the test stand we have been characterizing and studying CT formation,more » ejection/translation from the MCPG, and penetration into transverse magnetic fields.« less

Magnetic and electrostatic confinement of plasma with tuning of electrostatic field

DOEpatents

Rostoker, Norman [Irvine, CA; Binderbauer, Michl [Irvine, CA; Qerushi, Artan [Irvine, CA; Tahsiri, Hooshang [Irvine, CA

2008-10-21

A system and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions they are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

Magnetic and electrostatic confinement of plasma with tuning of electrostatic field

DOEpatents

Rostoker, Norman; Binderbauer, Michl; Qerushi, Artan; Tahsiri, Hooshang

2006-10-10

A system and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions they are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

Apparatus for magnetic and electrostatic confinement of plasma

DOEpatents

Rostoker, Norman; Binderbauer, Michl

2013-06-11

An apparatus and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions ions are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

Apparatus for magnetic and electrostatic confinement of plasma

DOEpatents

Rostoker, Norman; Binderbauer, Michl

2016-07-05

An apparatus and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions ions are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

Apparatus for magnetic and electrostatic confinement of plasma

DOEpatents

Rostoker, Norman; Binderbauer, Michl

2006-10-31

An apparatus and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions they are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

Apparatus for magnetic and electrostatic confinement of plasma

DOEpatents

Rostoker, Norman; Binderbauer, Michl

2006-04-11

An apparatus and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions they are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

Apparatus for magnetic and electrostatic confinement of plasma

DOEpatents

Rostoker, Norman [Irvine, CA; Binderbauer, Michl [Irvine, CA

2009-08-04

An apparatus and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions ions are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

Magnetic and electrostatic confinement of plasma with tuning of electrostatic field

DOEpatents

Rostoker, Norman; Binderbauer, Michl; Qerushi, Artan; Tahsiri, Hooshang

2006-03-21

A system and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions they are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

Electronics and Software Engineer for Robotics Project Intern

NASA Technical Reports Server (NTRS)

Teijeiro, Antonio

2017-01-01

I was assigned to mentor high school students for the 2017 First Robotics Competition. Using a team based approach, I worked with the students to program the robot and applied my electrical background to build the robot from start to finish. I worked with students who had an interest in electrical engineering to teach them about voltage, current, pulse width modulation, solenoids, electromagnets, relays, DC motors, DC motor controllers, crimping and soldering electrical components, Java programming, and robotic simulation. For the simulation, we worked together to generate graphics files, write simulator description format code, operate Linux, and operate SOLIDWORKS. Upon completion of the FRC season, I transitioned over to providing full time support for the LCS hardware team. During this phase of my internship I helped my co-intern write test steps for two networking hardware DVTs , as well as run cables and update cable running lists.

Final Scientific/Technical Report – DE-FG02-06ER64172 – Reaction-Based Reactive Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center – Subproject to Co-PI Eric E. Roden

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eric E. Roden

2009-03-17

This report summarizes research conducted in conjunction with a project entitled “Reaction-Based Reactive Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center”, which was funded through the Integrative Studies Element of the former NABIR Program (now the Environmental Remediation Sciences Program) within the Office of Biological and Environmental Research. Dr. William Burgos (The Pennsylvania State University) was the overall PI/PD for the project, which included Brian Dempsey (Penn State), Gour-Tsyh (George) Yeh (Central Florida University), and Eric Roden (formerly at The University of Alabama, now at the University of Wisconsin) as separately-fundedmore » co-PIs. The project focused on development of a mechanistic understanding and quantitative models of coupled Fe(III)/U(VI) reduction in FRC Area 2 sediments. The work builds on our previous studies of microbial Fe(III) and U(VI) reduction, and was directly aligned with the Scheibe et al. ORNL FRC Field Project at Area 2. Area 2 is a shallow pathway for migration of contaminated groundwater to seeps in the upper reach of Bear Creek at ORNL, mainly through a ca. 1 m thick layer of gravel located 4-5 m below the ground surface. The gravel layer is sandwiched between an overlying layer of disturbed fill material, and 2-3 m of undisturbed shale saprolite derived from the underlying Nolichucky Shale bedrock. The fill was put in place when contaminated soils were excavated and replaced by native saprolite from an uncontaminated area within Bear Creek Valley; the gravel layer was presumably installed prior to addition of the fill in order to provide a stable surface for the operation of heavy machinery. The undisturbed saprolite is highly weathered bedrock that has unconsolidated character but retains much of the bedding and fracture structure of the parent rock (shale with interbedded limestone). Hydrological tracer studies conducted during the Scheibe et al. field project indicate that the gravel layer receives input of uranium from both upstream sources and from diffusive mass transfer out of highly contaminated fill and saprolite materials above and below the gravel layer. This research sought to examine biogeochemical processes likely to take place in the less conductive materials above and below the gravel during the in situ ethanol biostimulation experiment conducted at Area 2 during 2005-2006. The in situ experiment in turn examined the hypothesis that injection of electron donor into this layer would induce formation of a redox barrier in the less conductive materials, resulting in decreased mass transfer of uranium out these materials and attendant declines in groundwater U(VI) concentration. Our research was directed toward the following three major objectives relevant to formation of this redox barrier: (1) elucidate the kinetics and mechanisms of reduction of solid-phase Fe(III) and U(VI) in Area 2 sediments; (2) evaluate the potential for long-term sustained U(IV) reductive immobilization in Area 2 sediments; (3) numerically simulate the suite of hydrobiogeochemical processes occurring in experimental systems so as to facilitate modeling of in situ U(IV) immobilization at the field-scale.« less

[Fiber reinforced composite posts: literature review].

PubMed

Frydman, G; Levatovsky, S; Pilo, R

2013-07-01

FRC (Fiber-reinforced composite) posts have been used since the beginning of the 90s with the introduction of carbon fiber posts. Fiber posts are widely used to restore endodontically treated teeth that have insufficient coronal tooth structure. Many in vitro and in vivo studies have shown the advantage of using FRC over prefabricated and cast metal post especially indicated in narrow root canals which are prone to vertically root fracture. The most frequent failure of FRC is debonding of a post at the resin cement/dentin interface. Bonding to dentin may be achieved by using etch-and-rinse and self-etch adhesives. The bond strength formed by self-adhesive cements is noticeably lower in comparison to the bond strength formed with resin cements applied in combination with etch-and-rinse adhesives. In an attempt to maximize resin bonding to fiber posts, several surface treatments have been suggested. Sandblasting with alumina particles results in an increased surface roughness and surface area without affecting the integrity of the post as long as it is applied by 50 microm alumina particles at 2.5 bars for maximally 5 seconds at a distance of 30 mm. The efficiency of post salinization is controversial and its contribution to the retention is of minor importance. Hydrofluoric acid has recently been proposed for etching glass fiber posts but this technique produced substantial damage to the glass fibers and affected the integrity of the post. Delayed cementation of fiber post (at least 24h post endodontic treatment) resulted in higher retentive strengths in comparison to immediate cementation and the best results were obtained when the luting agent was brought into the post space with lentulo spirals or specific syringes. The resin cement film thickness also influences the pullout strengths of fiber-reinforced posts .The highest bond strength values were obtained when the cement layer oversized the post spaces but not larger than 0.3 mm. The use of core build-up materials as post luting cements is not recommended. The use of FRC post, combined with proper adhesive cementation technique can give an excellent solution when restoring endodontically treated teeth that are prone to fracture.

Factors affecting construction of science discourse in the context of an extracurricular science and technology project

NASA Astrophysics Data System (ADS)

Webb, Horace P.

Doing and learning science are social activities that require certain language, activities, and values. Both constitute what Gee (2005) calls Discourses. The language of learning science varies with the learning context (Lemke, 2001,1990). Science for All Americans (AAAS, 1990) and Inquiry and the National Science Education Standards (NRC, 2000) endorse inquiry science learning. In the United States, most science learning is teacher-centered; inquiry science learning is rare (NRC, 2000). This study focused on 12 high school students from two suburban high schools, their three faculty mentors, and two engineering mentors during an extracurricular robotics activity with FIRST Robotics Competition (FRC). FRC employed student-centered inquiry focus to teach science principles integrating technology. Research questions were (a) How do science teachers and their students enact Discourses as they teach and learn science? and (b) How does the pedagogical approach of a learning activity facilitate the Discourses that are enacted by students and teachers as they learn and teach science? Using Critical Discourse Analysis (CDA), the study examined participants' language during robotic activities to determine how language used in learning science shaped the learning and vice versa. Data sources included videorecordings of participant language and semi-structured interviews with study participants. Transcribed recordings were coded initially using Gee's (2005) linguistic Building Tasks as a priori codes. CDA was applied to code transcripts, to construct Discourses enacted by the participants, and to determine how context facilitated their enactment. Findings indicated that, for the students, FRC facilitated elements of Science Discourse. Wild About Robotics (W.A.R.) team became, through FRC, part of a community similar to scientists' community that promoted knowledge and sound practices, disseminated information, supported research and development and encouraged interaction of its members. The public school science classroom in the U.S. is inimical to inquiry learning because of practices and policies associated with the epistemological stance that spawned the standards and/or testing movement and No Child Left Behind (Baez & Boyles, 2009). The findings of this study provided concrete ideas to accommodate the recommendations by NRC (1996) and NSES (2000) for creating contexts that might lead to inquiry science learning for meaningful student engagement.

Deriving sediment Interstitial Water Remediation Goals (IWRGs) for the protection of benthic organisms from direct toxicity

EPA Science Inventory

Background/Objectives. Passive sampling is becoming a frequently used measurement technique at Superfund sites with contaminated sediments. Passive sampling measures the concentrations of freely dissolved chemicals (Cfrees) in the sediment interstitial water. The freely dissol...

Geochemical baseline level and function and contamination of phosphorus in Liao River Watershed sediments of China.

PubMed

Liu, Shaoqing; Wang, Jing; Lin, Chunye; He, Mengchang; Liu, Xitao

2013-10-15

The quantitative assessment of P contamination in sediments is a challenge due to sediment heterogeneity and the lacking of geochemical background or baseline levels. In this study, a procedure was proposed to determine the average P background level and P geochemical baseline level (GBL) and develop P geochemical baseline functions (GBF) for riverbed sediments of the Liao River Watershed (LRW). The LRW has two river systems - the Liao River System (LRS) and the Daliao River System (DRS). Eighty-eight samples were collected and analyzed for P, Al, Fe, Ca, organic matter, pH, and texture. The results show that Fe can be used as a better particle-size proxy to construct the GBF of P (P (mg/kg) = 39.98 + 166.19 × Fe (%), R(2) = 0.835, n = 66). The GBL of P was 675 mg/kg, while the average background level of P was 355 mg/kg. Noting that many large cities are located in the DRS watershed, most of the contaminated sites were located within the DRS and the riverbed sediments were more contaminated by P in the DRS watershed than in the LRS watershed. The geochemical background and baseline information of P are of great importance in managing P levels within the LRW. Copyright © 2013 Elsevier Ltd. All rights reserved.

Reprint of Mechanisms of maintaining high suspended sediment concentration over tide-dominated offshore shoals in the southern Yellow Sea

NASA Astrophysics Data System (ADS)

Xiong, Jilian; Wang, Xiao Hua; Wang, Ya Ping; Chen, Jingdong; Shi, Benwei; Gao, Jianhua; Yang, Yang; Yu, Qian; Li, Mingliang; Yang, Lei; Gong, Xulong

2018-06-01

An understanding of the dynamics and behaviors of suspended sediments is vital in analysis of morphological, environmental, and ecological processes occurring in coastal marine environments. To study the mechanisms of maintaining high suspended sediment concentrations (SSCs) on a tide-dominated offshore shoal, we measured water depths, current velocities, SSCs, wave parameters and bottom sediment compositions in the southern Yellow Sea. These data were then used to calculate bottom shear stresses generated by currents (τc), waves (τw), and wave-current interactions (τcw). SSCs time series exhibited strong quarter-diurnal peaks during spring tides, in contrast to the semidiurnal signal during neap tides. A Fourier analysis showed that suspended sediment variations within tidal cycles was mainly controlled by resuspension in most stations. There existed relatively stable background SSCs (maintaining high SSCs among tidal cycles) values at all four stations during both windy (wind speed > 9.0 m/s) and normal weather conditions (wind speed < 3.0 m/s). The background SSCs had strong relationship with spring/neap-averaged τcw, indicating background SSCs were mainly controlled by mean bottom shear stress, with a minimum value of 0.21 N/m2. On account of the strong tidal currents, background SSCs of spring tides were greater than that of neap tides. In addition, on the base of wavelet, statistics analyses and turbulence dissipation parameter, background SSCs during slack tide in the study area may be maintained by intermittent turbulence events induced by a combined tidal current and wave action.

Mechanisms of maintaining high suspended sediment concentration over tide-dominated offshore shoals in the southern Yellow Sea

NASA Astrophysics Data System (ADS)

Xiong, Jilian; Wang, Xiao Hua; Wang, Ya Ping; Chen, Jingdong; Shi, Benwei; Gao, Jianhua; Yang, Yang; Yu, Qian; Li, Mingliang; Yang, Lei; Gong, Xulong

2017-05-01

An understanding of the dynamics and behaviors of suspended sediments is vital in analysis of morphological, environmental, and ecological processes occurring in coastal marine environments. To study the mechanisms of maintaining high suspended sediment concentrations (SSCs) on a tide-dominated offshore shoal, we measured water depths, current velocities, SSCs, wave parameters and bottom sediment compositions in the southern Yellow Sea. These data were then used to calculate bottom shear stresses generated by currents (τc), waves (τw), and wave-current interactions (τcw). SSCs time series exhibited strong quarter-diurnal peaks during spring tides, in contrast to the semidiurnal signal during neap tides. A Fourier analysis showed that suspended sediment variations within tidal cycles was mainly controlled by resuspension in most stations. There existed relatively stable background SSCs (maintaining high SSCs among tidal cycles) values at all four stations during both windy (wind speed > 9.0 m/s) and normal weather conditions (wind speed < 3.0 m/s). The background SSCs had strong relationship with spring/neap-averaged τcw, indicating background SSCs were mainly controlled by mean bottom shear stress, with a minimum value of 0.21 N/m2. On account of the strong tidal currents, background SSCs of spring tides were greater than that of neap tides. In addition, on the base of wavelet, statistics analyses and turbulence dissipation parameter, background SSCs during slack tide in the study area may be maintained by intermittent turbulence events induced by a combined tidal current and wave action.

Mechanical properties and ultrastructural characteristics of a glass fiber-reinforced composite.

PubMed

García Barbero, Alvaro Enrique; Vera González, Vicente; García Barbero, Ernesto; Aliaga Vera, Ignacio

2015-06-01

To examine the ultrastructural characteristics of a fiber-reinforced composite (FRC) and its behavior in vitro as a framework for fixed partial dentures (FPDs). A total of 40 specimens were prepared using extracted teeth fixed in methacrylate blocks as supports for the FPD, then the specimens were divided into four groups depending on whether a retaining box was used to fix the FPD to the support teeth, and on whether a composite pontic was assembled on top of the fibers. Fracture testing was performed in a universal testing machine (1 mm/minute). Fracture strength values and failure types were statistically compared for each group. Using retaining boxes did not improve the mechanical behavior of the restorative system. The weakest element of the system was the composite tooth constructed on top of the FRC.

Advanced Biasing Experiments on the C-2 Field-Reversed Configuration Device

NASA Astrophysics Data System (ADS)

Thompson, Matthew; Korepanov, Sergey; Garate, Eusebio; Yang, Xiaokang; Gota, Hiroshi; Douglass, Jon; Allfrey, Ian; Valentine, Travis; Uchizono, Nolan; TAE Team

2014-10-01

The C-2 experiment seeks to study the evolution, heating and sustainment effects of neutral beam injection on field-reversed configuration (FRC) plasmas. Recently, substantial improvements in plasma performance were achieved through the application of edge biasing with coaxial plasma guns located in the divertors. Edge biasing provides rotation control that reduces instabilities and E × B shear that improves confinement. Typically, the plasma gun arcs are run at ~ 10 MW for the entire shot duration (~ 5 ms), which will become unsustainable as the plasma duration increases. We have conducted several advanced biasing experiments with reduced-average-power plasma gun operating modes and alternative biasing cathodes in an effort to develop an effective biasing scenario applicable to steady state FRC plasmas. Early results show that several techniques can potentially provide effective, long-duration edge biasing.

Fully-kinetic Ion Simulation of Global Electrostatic Turbulent Transport in C-2U

NASA Astrophysics Data System (ADS)

Fulton, Daniel; Lau, Calvin; Bao, Jian; Lin, Zhihong; Tajima, Toshiki; TAE Team

2017-10-01

Understanding the nature of particle and energy transport in field-reversed configuration (FRC) plasmas is a crucial step towards an FRC-based fusion reactor. The C-2U device at Tri Alpha Energy (TAE) achieved macroscopically stable plasmas and electron energy confinement time which scaled favorably with electron temperature. This success led to experimental and theoretical investigation of turbulence in C-2U, including gyrokinetic ion simulations with the Gyrokinetic Toroidal Code (GTC). A primary objective of TAE's new C-2W device is to explore transport scaling in an extended parameter regime. In concert with the C-2W experimental campaign, numerical efforts have also been extended in A New Code (ANC) to use fully-kinetic (FK) ions and a Vlasov-Poisson field solver. Global FK ion simulations are presented. Future code development is also discussed.

A microprocessor-controlled tracheal insufflation-assisted total liquid ventilation system.

PubMed

Parker, James Courtney; Sakla, Adel; Donovan, Francis M; Beam, David; Chekuri, Annu; Al-Khatib, Mohammad; Hamm, Charles R; Eyal, Fabien G

2009-09-01

A prototype time cycled, constant volume, closed circuit perfluorocarbon (PFC) total liquid ventilator system is described. The system utilizes microcontroller-driven display and master control boards, gear motor pumps, and three-way solenoid valves to direct flow. A constant tidal volume and functional residual capacity (FRC) are maintained with feedback control using end-expiratory and end-inspiratory stop-flow pressures. The system can also provide a unique continuous perfusion (bias flow, tracheal insufflation) through one lumen of a double-lumen endotracheal catheter to increase washout of dead space liquid. FRC and arterial blood gases were maintained during ventilation with Rimar 101 PFC over 2-3 h in normal piglets and piglets with simulated pulmonary edema induced by instillation of albumin solution. Addition of tracheal insufflation flow significantly improved the blood gases and enhanced clearance of instilled albumin solution during simulated edema.

Formation of a field reversed configuration for magnetic and electrostatic confinement of plasma

DOEpatents

Rostoker, Norman; Binderbauer, Michl

2003-12-16

A system and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions they are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

Formation of a field reversed configuration for magnetic and electrostatic confinement of plasma

DOEpatents

Rostoker, Norman; Binderbauer, Michl; Qerushi, Artan; Tahsiri, Hooshang

2007-02-20

A system and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions they are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

Formation of a field reversed configuration for magnetic and electrostatic confinement of plasma

DOEpatents

Rostoker, Norman; Binderbauer, Michl; Qerushi, Artan; Tahsiri, Hooshang

2006-02-07

A system and method for containing plasma and forming a Field Reversed Configuration (FRC) magnetic topology are described in which plasma ions are contained magnetically in stable, non-adiabatic orbits in the FRC. Further, the electrons are contained electrostatically in a deep energy well, created by tuning an externally applied magnetic field. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In this configuration, ions and electrons may have adequate density and temperature so that upon collisions they are fused together by nuclear force, thus releasing fusion energy. Moreover, the fusion fuel plasmas that can be used with the present confinement system and method are not limited to neutronic fuels only, but also advantageously include advanced fuels.

Use of sediment-trace element geochemical models for the identification of local fluvial baseline concentrations

USGS Publications Warehouse

Horowitz, A.J.; Elrick, K.A.; Demas, C.R.; Demcheck, D.K.

1991-01-01

Studies have demonstrated the utility of fluvial bed sediment chemical data in assesing local water-quality conditions. However, establishing local background trace element levels can be difficult. Reference to published average concentrations or the use of dated cores are often of little use in small areas of diverse local petrology, geology, land use, or hydrology. An alternative approach entails the construction of a series of sediment-trace element predictive models based on data from environmentally diverse but unaffected areas. Predicted values could provide a measure of local background concentrations and comparison with actual measured concentrations could identify elevated trace elements and affected sites. Such a model set was developed from surface bed sediments collected nationwide in the United States. Tests of the models in a small Louisiana basin indicated that they could be used to establish local trace element background levels, but required recalibration to account for local geochemical conditions outside the range of samples used to generate the nationwide models.

The influence of pressure changes on the retentive force and coronal microleakage of different types of posts in endodontically treated teeth during simulated dives.

PubMed

Mitov, Gergo; Draenert, Florian; Schumann, Paul; Stötzer, Marcus; von See, Constantin

2016-12-01

We assessed the influence of a simulated diving environment on the interfacial microleakage and retentive forces of different post types in root-canal-filled teeth. One-hundred-and-twenty extracted, single-rooted teeth were endodontically treated and were randomly divided into three groups according to the post and cement used: ER Post/Harvard cement (Titanium), CeraPost/DentinBuild Evo (Zirconia), DT Light Post/Calibra (FRC). Each group was randomly divided into two equal subgroups, a control group, and an experimental group, subjected to simulated dives to 456 kPa in a diving chamber. For 10 specimens of each subgroup the pull-out strength and the coronal microleakage were measured. Significant differences in the linear coronal penetration were observed between the Titanium and FRC groups (experimental group P ≤ 0.001; control group P = 0.02). Diving simulation had no significant impact on the microleakage for the three post types. The FRC groups showed significantly higher retentive strength values compared to the Titanium and Zirconia groups before and after simulated diving. The pull-out strength of the titanium experimental group was significantly less than the control group (P = 0.008). Following root canal treatment the combination of fibre-reinforced posts and resin cement should be preferred for patients requiring retention for tooth restorations using posts that are likely to be exposed to hyperbaric conditions.

a Search for Lower-Hybrid Drift Fluctuations in a Field-Reversed Configuration by Means of Carbon Dioxide Heterodyne Scattering.

NASA Astrophysics Data System (ADS)

Carlson, Arthur William

A measurement is reported which sets an upper bound on LHD-like density fluctuations in an FRC which is two orders of magnitude below the predicted levels. Particle loss from FRC's is known to occur anomalously fast, and this is usually attributed to effects of the LHD instability. If LHD waves are present, they can be measured using heterodyne detection of CO(,2) laser light scattered from the associated density fluctuations. In the present case, the usual scattering system was successfully modified to compensate for severe refraction of the beams by the plasma. This system was calibrated by detection of an electrooptically modulated CO(,2) laser beam, and by detection of light scattered from acoustic waves in salt. The plasma measurements made on the TRX-2 field-reversed theta-pinch covered all parameters at which LHD fluctuations might be expected to occur, namely wavenumbers from 30 to 240 cm('-1), frequencies from 10 to 300 MHz, and radii from one centimeter inside the separatrix to two centimeters outside. The lack of detectable scattered light under any of these conditions indicates ((delta)n/n) < 1 x 10('-4), compared to predictions of ((delta)n/n) ('(TURN)) 1 x 10('-2) based on mode coupling theory, ion -trapping theory, and observed transport rates. Several mechanisms are discussed which may stabilize LHD in these plasmas. Several alternate explanations of the observed anomalous transport rates in FRC's are also discussed.

Experimental study of the formation of field-reversed configurations employing high-order multipole fields

NASA Astrophysics Data System (ADS)

Slough, J. T.; Hoffman, A. L.

1990-04-01

A high-order multipole ``barrier'' field was applied at the vacuum tube wall in the TRX experiment [Phys. Fluids B 1, 840 (1989)] during both the preionization and field reversal phases of field-reversed configuration (FRC) formation. Use of this field during field reversal resulted in a significant reduction of impurities as well as increased flux trapping. With a large enough Bθ at the wall, sheath detachment from the wall became apparent, and flux loss through the sheath became negligible (<10%). At larger wall Bθ (>1.5 kG), destructive rotational spin-up occurred, driven by Hall current forces. When the multipole barrier field was also applied during either axial discharge or ringing theta current preionization, a very symmetric and uniform breakdown of the fill gas was achieved. In particular, using ringing theta preionization, complete ionization of the fill gas was accomplished with purely inductive fields of remarkably low magnitude, where Ez≤3 V/cm, and Eθ≤20 V/cm. Due to the improved ionization symmetry, about 65% to 75% of the lift-off flux (flux remaining after field reversal) could be retained through the remaining formation processes into an equilibrium FRC. Using the multipole field during both preionization and formation, it was possible to form FRC's with good confinement with greater than 3 mWb of trapped flux at 15 mTorr D2 or H2 in a 10 cm radius device. Values of s in excess of 4 could be achieved in this manner.

High-beta spherical tokamak startup in TS-4 merging experiment by use of toroidal field ramp-up

NASA Astrophysics Data System (ADS)

Kaminou, Yasuhiro; , Toru, II; Kato, Joji; Inomoto, Michiaki; Ono, Yasushi; TS Group Team; National InstituteFusion Science Collaboration

2014-10-01

We demonstrated the formation method of an ultrahigh-beta spherical tokamak by use of a field-reversed configuration and a spheromak in TS-4 device (R ~ 0.5 m, A ~ 1.5, Ip ~ 30-100 kA, B ~ 100 mT). This method is composed of the following steps: 1. Two spheromaks are merged together and a high-beta spheromak or FRC is formed by reconnection heating. 2. External toroidal magnetic field is added (current rising time ~50 μs), and spherical tokamak-like configuration is formed. In this way, the ultrahigh-beta ST is formed. The ultrahigh-beta ST formed by FRC has a diamagnetic toroidal field, and it presumed to be in a second-stable state for ballooning stability, and the one formed by spheromak has a weak paramagnetic toroidal magnetic field, while a spheormak has a strong paramagnetic toroidal magnetic field. This diamagnetic current derives from inductive electric field by ramping up the external toroidal magnetic field, and the diamagnetic current sustains high thermal pressure of the ultrahigh-beta spherical tokamak. And the beta of the ultrahigh-beta ST formed by FRC reaches about 50%. To sustain the high-beta state, 0.6 MW neutral beam injection and center solenoid coils are installed to the TS-4 device. In the poster, we report the experimental results of ultrahigh-beta spherical tokamak startup and sustainment by NBI and CS current driving experiment.

Scaling Study of Reconnection Heating in Torus Plasma Merging Experiments

NASA Astrophysics Data System (ADS)

Ono, Yasushi; Akimitsu, Moe; Sawada, Asuka; Cao, Qinghong; Koike, Hideya; Hatano, Hironori; Kaneda, Taishi; Tanabe, Hiroshi

2017-10-01

We have been investigating toroidal plasma merging and reconnection for high-power heating of spherical tokamak (ST) and field-reversed configuration (FRC), using TS-3 (ST, FRC: R =0.2m, 1985-), TS-4 (ST, FRC: R =0.5m, 2000-), UTST (ST: R =0.45m, 2008-) and MAST (ST: R =0.9m, 2000-) devices. The series of merging experiments made clear the promising scaling and characteristics of reconnection heating: (i) its ion heating energy that scales with square of the reconnecting magnetic field Brec, (ii) its energy loss lower than 10%, (iii) its ion heating energy (in the downstream) 10 time larger than its electron heating energy (at around X-point) and (iv) low dependence of ion heating on the guide (toroidal) field Bg. The Brec2-scalingwas obtained when the current sheet was compressed to the order of ion gyrodadius. When the sheet was insufficiently compressed, the measured ion temperature was lower than the scaling prediction. Based on this scaling, we realized significant ion heating up to 1.2keV in MAST after 2D elucidation of ion heating up to 250eV in TS-3 [3,4]. This promising scaling leads us to new high Brec reconnection heating experiments for future direct access to burning plasma: TS-U (2017-) in Univ. Tokyo and ST-40 in Tokamak Energy Inc. (2017-). This presentation reviews major progresses in those toroidal plasma merging experiments for physics and fusion applications of magnetic reconnection.

Point-of-Purchase Labels and Reward Cards Improve Sales of Healthy Foods in University Dining Halls.

PubMed

Biden, Catherine R; Matthews, June I; Laframboise, Natalie A; Zok, Anne; Dworatzek, Paula D N; Seabrook, Jamie A

2018-06-12

To compare sales of Food Resources and Education for Student Health (FRESH) Approved versus non-FRESH Approved menu cycle items pre- and postimplementation of the FRESH program. Sales data from 2011-2015 of FRESH Approved versus non-FRESH Approved menu items were analyzed. Fruit and milk items sold, net sales, and the cost of free fruit and milk redeemed through the FRESH Reward Card (FRC) program, were also analyzed. FRESH Approved items sold more often than non-FRESH Approved items in the latter 2 years (P = 0.01). Prices of FRESH Approved menu items were significantly lower than non-FRESH Approved items for all years (e.g., $1.52 ± $0.94 vs $2.21 ± $1.02 per serving in 2014-2015; P < 0.001). Across all FRESH implementation years, FRESH Approved menu items were found more often on the 6-week menu (P < 0.05). The number of fruit items sold increased from a baseline of 143 052 to 170 954, and net sales increased from $135 450 to $154 248 after 3 years of the FRC implementation. FRESH Approved items were less expensive, available more often, and had higher sales. The FRC increased net fruit sales despite the cost of free fruit. Highlighting and reducing the cost of healthy foods are promising practices to improve campus food environments.

Should PEEP Titration Be Based on Chest Mechanics in Patients With ARDS?

PubMed

Kallet, Richard H

2016-06-01

Functional residual capacity (FRC) is essentially the alveolar volume and a determinant of both oxygenation and respiratory system compliance (CRS). ARDS decreases FRC, and sufficient PEEP restores FRC; thus, assessments of PEEP by its impact on oxygenation and CRS are intimately linked. PEEP also can ameliorate or aggravate ventilator-induced lung injury. Therefore, it can be argued that PEEP should be titrated primarily by its impact on CRS The pro position argues that the heterogeneous nature of lung injury and its unique presentation in individual patients results in an uncoupling between oxygenation and CRS Therefore, relying upon oxygenation alone may enhance lung injury and mortality risk, particularly in those with severe ARDS. The con argument is that the preponderance of preclinical and clinical evidence suggests that a relatively narrow range of PEEP is required to manage all but the most severe cases of ARDS. In addition, pathological alterations in chest wall compliance confuse the interpretation of chest mechanics. Moreover, ambiguities and technical limitations in advanced techniques, such as esophageal manometry and pressure-volume curves, add a layer of complexity that renders its broader application in all ARDS patients both impractical and unnecessary. Whether sophisticated monitoring of chest mechanics in severe ARDS might improve outcomes further is open to question and should be studied further. However, it is highly improbable that we will ever discover a PEEP strategy that optimizes all aspects of cardiorespiratory function and chest mechanics for individual patients suffering from ARDS. Copyright © 2016 by Daedalus Enterprises.

Soil, Groundwater, Surface Water, and Sediments of Kennedy Space Center, Florida: Background Chemical and Physical Characteristics

NASA Technical Reports Server (NTRS)

Shmalzer, Paul A.; Hensley, Melissa A.; Mota, Mario; Hall, Carlton R.; Dunlevy, Colleen A.

2000-01-01

This study documented background chemical composition of soils, groundwater, surface; water, and sediments of Kennedy Space Center. Two hundred soil samples were collected, 20 each in 10 soil classes. Fifty-one groundwater wells were installed in 4 subaquifers of the Surficial Aquifer and sampled; there were 24 shallow, 16 intermediate, and 11 deep wells. Forty surface water and sediment samples were collected in major watershed basins. All samples were away from sites of known contamination. Samples were analyzed for organochlorine pesticides, aroclors, chlorinated herbicides, polycyclic aromatic hydrocarbons (PAH), total metals, and other parameters. All aroclors (6) were below detection in all media. Some organochlorine pesticides were detected at very low frequencies in soil, sediment, and surface water. Chlorinated herbicides were detected at very low frequencies in soil and sediments. PAH occurred in low frequencies in soiL, shallow groundwater, surface water, and sediments. Concentrations of some metals differed among soil classes, with subaquifers and depths, and among watershed basins for surface water but not sediments. Most of the variation in metal concentrations was natural, but agriculture had increased Cr, Cu, Mn, and Zn.

The effect of lung deformation on the spatial distribution of pulmonary blood flow.

PubMed

Arai, Tatsuya J; Theilmann, Rebecca J; Sá, Rui Carlos; Villongco, Michael T; Hopkins, Susan R

2016-11-01

Pulmonary perfusion measurement using magnetic resonance imaging combined with deformable image registration enabled us to quantify the change in the spatial distribution of pulmonary perfusion at different lung volumes. The current study elucidated the effects of tidal volume lung inflation [functional residual capacity (FRC) + 500 ml and FRC + 1 litre] on the change in pulmonary perfusion distribution. Changes in hydrostatic pressure distribution as well as transmural pressure distribution due to the change in lung height with tidal volume inflation are probably bigger contributors to the redistribution of pulmonary perfusion than the changes in pulmonary vasculature resistance caused by lung tissue stretch. Tidal volume lung inflation results in structural changes in the pulmonary circulation, potentially affecting pulmonary perfusion. We hypothesized that perfusion is recruited to regions receiving the greatest deformation from a tidal breath, thus ensuring ventilation-perfusion matching. Density-normalized perfusion (DNP) magnetic resonance imaging data were obtained in healthy subjects (n = 7) in the right lung at functional residual capacity (FRC), FRC+500 ml, and FRC+1.0 l. Using deformable image registration, the displacement of a sagittal lung slice acquired at FRC to the larger volumes was calculated. Registered DNP images were normalized by the mean to estimate perfusion redistribution (nDNP). Data were evaluated across gravitational regions (dependent, middle, non-dependent) and by lobes (upper, RUL; middle, RML; lower, RLL). Lung inflation did not alter mean DNP within the slice (P = 0.10). The greatest expansion was seen in the dependent region (P < 0.0001: dependent vs non-dependent, P < 0.0001: dependent vs middle) and RLL (P = 0.0015: RLL vs RUL, P < 0.0001: RLL vs RML). Neither nDNP recruitment to RLL [+500 ml = -0.047(0.145), +1 litre = 0.018(0.096)] nor to dependent lung [+500 ml = -0.058(0.126), +1 litre = -0.023(0.106)] were found. Instead, redistribution was seen in decreased nDNP in the non-dependent [+500 ml = -0.075(0.152), +1 litre = -0.137(0.167)) and increased nDNP in the gravitational middle lung [+500 ml = 0.098(0.058), +1 litre = 0.093(0.081)] (P = 0.01). However, there was no significant lobar redistribution (P < 0.89). Contrary to our hypothesis, based on the comparison between gravitational and lobar perfusion data, perfusion was not redistributed to the regions of the most inflation. This suggests that either changes in hydrostatic pressure or transmural pressure distribution in the gravitational direction are implicated in the redistribution of perfusion away from the non-dependent lung. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

The effect of lung deformation on the spatial distribution of pulmonary blood flow

PubMed Central

Arai, Tatsuya J.; Theilmann, Rebecca J.; Sá, Rui Carlos; Villongco, Michael T.

2016-01-01

Key points Pulmonary perfusion measurement using magnetic resonance imaging combined with deformable image registration enabled us to quantify the change in the spatial distribution of pulmonary perfusion at different lung volumes.The current study elucidated the effects of tidal volume lung inflation [functional residual capacity (FRC) + 500 ml and FRC + 1 litre] on the change in pulmonary perfusion distribution.Changes in hydrostatic pressure distribution as well as transmural pressure distribution due to the change in lung height with tidal volume inflation are probably bigger contributors to the redistribution of pulmonary perfusion than the changes in pulmonary vasculature resistance caused by lung tissue stretch. Abstract Tidal volume lung inflation results in structural changes in the pulmonary circulation, potentially affecting pulmonary perfusion. We hypothesized that perfusion is recruited to regions receiving the greatest deformation from a tidal breath, thus ensuring ventilation–perfusion matching. Density‐normalized perfusion (DNP) magnetic resonance imaging data were obtained in healthy subjects (n = 7) in the right lung at functional residual capacity (FRC), FRC+500 ml, and FRC+1.0 l. Using deformable image registration, the displacement of a sagittal lung slice acquired at FRC to the larger volumes was calculated. Registered DNP images were normalized by the mean to estimate perfusion redistribution (nDNP). Data were evaluated across gravitational regions (dependent, middle, non‐dependent) and by lobes (upper, RUL; middle, RML; lower, RLL). Lung inflation did not alter mean DNP within the slice (P = 0.10). The greatest expansion was seen in the dependent region (P < 0.0001: dependent vs non‐dependent, P < 0.0001: dependent vs middle) and RLL (P = 0.0015: RLL vs RUL, P < 0.0001: RLL vs RML). Neither nDNP recruitment to RLL [+500 ml = −0.047(0.145), +1 litre = 0.018(0.096)] nor to dependent lung [+500 ml = −0.058(0.126), +1 litre = −0.023(0.106)] were found. Instead, redistribution was seen in decreased nDNP in the non‐dependent [+500 ml = −0.075(0.152), +1 litre = −0.137(0.167)) and increased nDNP in the gravitational middle lung [+500 ml = 0.098(0.058), +1 litre = 0.093(0.081)] (P = 0.01). However, there was no significant lobar redistribution (P < 0.89). Contrary to our hypothesis, based on the comparison between gravitational and lobar perfusion data, perfusion was not redistributed to the regions of the most inflation. This suggests that either changes in hydrostatic pressure or transmural pressure distribution in the gravitational direction are implicated in the redistribution of perfusion away from the non‐dependent lung. PMID:27273807

Economical concrete mix design utilizing blended cements, performance-based specifications, and pay factors.

DOT National Transportation Integrated Search

2013-05-01

This report showcases several new approaches of using materials science and structural mechanics to accomplish : sustainable design of concrete materials. The topics addressed include blended cements, fiber-reinforced concrete : (FRC), internal curin...

Effects of mechanical properties of adhesive resin cements on stress distribution in fiber-reinforced composite adhesive fixed partial dentures.

PubMed

Yokoyama, Daiichiro; Shinya, Akikazu; Gomi, Harunori; Vallittu, Pekka K; Shinya, Akiyoshi

2012-01-01

Using finite element analysis (FEA), this study investigated the effects of the mechanical properties of adhesive resin cements on stress distributions in fiber-reinforced resin composite (FRC) adhesive fixed partial dentures (AFPDs). Two adhesive resin cements were compared: Super-Bond C&B and Panavia Fluoro Cement. The AFPD consisted of a pontic to replace a maxillary right lateral incisor and retainers on a maxillary central incisor and canine. FRC framework was made of isotropic, continuous, unidirectional E-glass fibers. Maximum principal stresses were calculated using finite element method (FEM). Test results revealed that differences in the mechanical properties of adhesive resin cements led to different stress distributions at the cement interfaces between AFPD and abutment teeth. Clinical implication of these findings suggested that the safety and longevity of an AFPD depended on choosing an adhesive resin cement with the appropriate mechanical properties.

Performance improvement of magnetized coaxial plasma gun by magnetic circuit on a bias coil

NASA Astrophysics Data System (ADS)

Edo, Takahiro; Matsumoto, Tadafumi; Asai, Tomohiko; Kamino, Yasuhiro; Inomoto, Michiaki; Gota, Hiroshi

2016-10-01

A magnetized coaxial plasmoid accelerator has been utilized for compact torus (CT) injection to refuel into fusion reactor core plasma. Recently, CT injection experiments have been conducted on the C-2/C-2U facility at Tri Alpha Energy. In the series of experiments successful refueling, i.e. increased particle inventory of field-reversed configuration (FRC) plasma, has been observed. In order to improve the performance of CT injector and to refuel in the upgraded FRC device, called C-2W, with higher confinement magnetic field, magnetic circuit consisting of magnetic material onto a bias magnetic coil is currently being tested at Nihon University. Numerical work suggests that the optimized bias magnetic field distribution realizes the increased injection velocity because of higher conversion efficiency of Lorenz self force to kinetic energy. Details of the magnetic circuit design as well as results of the test experiment and field calculations will be presented and discussed.

The Pulsed High Density Experiment (PHDX) Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slough, John P.; Andreason, Samuel

The purpose of this paper is to present the conclusions that can be drawn from the Field Reversed Configuration (FRC) formation experiments conducted on the Pulsed High Density experiment (PHD) at the University of Washington. The experiment is ongoing. The experimental goal for this first stage of PHD was to generate a stable, high flux (>10 mWb), high energy (>10 KJ) target FRC. Such results would be adequate as a starting point for several later experiments. This work focuses on experimental implementation and the results of the first four month run. Difficulties were encountered due to the initial on-axis plasmamore » ionization source. Flux trapping with this ionization source acting alone was insufficient to accomplish experimental objectives. Additional ionization methods were utilized to overcome this difficulty. A more ideal plasma source layout is suggested and will be explored during a forthcoming work.« less

A search for lower-hybrid-drift fluctuations in a field-reversed configuration using CO2 heterodyne scattering

NASA Astrophysics Data System (ADS)

Carlson, Arthur W.

1987-05-01

An upper bound of (ñe/ne) <10-4 for frequencies and wavenumbers relevant to the lower-hybrid-drift (LHD) instability is set on fluctuations in field-reversed configurations (FRC's) produced by TRX-2 [Fusion Techn. 9, 48 (1986)]. LHD is a well-studied microinstability that is often invoked to explain particle loss rates in FRC's. The conventional technique of CO2 laser scattering with heterodyne detection is here modified to compensate for severe refraction. The calibration of the system is verified by scattering from acoustic waves in salt. The measured bound is two orders of magnitude below both the fluctuation level usually predicted and the level needed to account for observed particle loss rates. Electron collisionality is identified as the most likely LHD stabilization mechanism. Some alternative explanations of anomalous loss rates are discussed.

Absolute calibration of neutron detectors on the C-2U advanced beam-driven FRC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Magee, R. M., E-mail: rmagee@trialphaenergy.com; Clary, R.; Korepanov, S.

2016-11-15

In the C-2U fusion energy experiment, high power neutral beam injection creates a large fast ion population that sustains a field-reversed configuration (FRC) plasma. The diagnosis of the fast ion pressure in these high-performance plasmas is therefore critical, and the measurement of the flux of neutrons from the deuterium-deuterium (D-D) fusion reaction is well suited to the task. Here we describe the absolute, in situ calibration of scintillation neutron detectors via two independent methods: firing deuterium beams into a high density gas target and calibration with a 2 × 10{sup 7} n/s AmBe source. The practical issues of each methodmore » are discussed and the resulting calibration factors are shown to be in good agreement. Finally, the calibration factor is applied to C-2U experimental data where the measured neutron rate is found to exceed the classical expectation.« less

Introduction to D-He(3) fusion reactors

NASA Technical Reports Server (NTRS)

Vlases, G. C.; Steinhauer, L. C.

1989-01-01

A review and evaluation of D-He(3) fusion reactor technology is presented. The advantages and disadvantages of the D-He(3) and D-T reactor cycles are outlined and compared. In addition, the general design features of D-He(3) tokamaks and field reversed configuration (FRC) reactors are described and the relative merits of each are compared. It is concluded that both tokamaks and FRC's offer certain advantages, and that the ultimate decision as to which to persue for terrestrial power generation will depend heavily on how the physics performance of each of them develops over the next few years. It is clear that the D-He(3) fuel cycle offers marked advantages over the D-T cycle. Although the physics requirements for D-He(3) are more demanding, the overwhelming advantages resulting from the two order of magnitude reduction of neutron flux are expected to lead to a shorter time to commercialization than for the D-T cycle.

Cardiopulmonary readjustments in passive tilt

NASA Technical Reports Server (NTRS)

Matalon, S. V.; Farhi, L. E.

1979-01-01

The readjustment of cardiopulmonary variables in human volunteers at various tilt angles on a tilt board is studied. Five healthy subjects (18-31 yr) with thorough knowledge of the experimental protocol are tested, passively tilted from the supine to the upright position in 15-deg increments in random sequence. The parameters measured are cardiac output (Q), heart rate (HR), stroke volume (SV), minute and alveolar ventilation /V(E) and V(A)/, functional residual capacity (FRC), and arterial-end-tidal P(CO2) pressure difference. It is found that changes in Q and FRC are linearly related to the sine of the tilt angle, indicating that either reflexes are absent or their net effect is proportional to the effects of gravity. This is clearly not the case for other variables /HR, SV, V(E), V(A)/, where it is possible to demonstrate threshold values for the appearance of secondary changes.

Cost Modeling and Design of Field-Reversed Configuration Fusion Power Plants

NASA Astrophysics Data System (ADS)

Kirtley, David; Slough, John; Helion Team

2017-10-01

The Inductively Driven Liner (IDL) fusion concept uses the magnetically driven implosion of thin (0.5-1 mm) Aluminum hoops to magnetically compress a merged Field-Reversed Configuration (FRC) plasma to fusion conditions. Both the driver and the target have been studied experimentally and theoretically by researchers at Helion Energy, MSNW, and the University of Washington, demonstrating compression fields greater than 100 T and suitable fusion targets. In the presented study, a notional power plant facility using this approach will be described. In addition, a full cost study based on the LLNL Z-IFE and HYLIFE-II studies, the ARIES Tokamak concept, and RAND power plant studies will be described. Finally, the expected capital costs, development requirements, and LCOE for 50 and 500 MW power plants will be given. This analysis includes core FRC plant scaling, metallic liner recycling, radiation shielding, operations, and facilities capital requirements.

Magnetic Diagnostics on the Magnetized Shock Experiment (MSX)

NASA Astrophysics Data System (ADS)

Hutchinson, T. M.; Weber, T. E.; Boguski, J. C.; Intrator, T. P.; Smith, R. J.; Dunn, J. P.

2013-10-01

The Magnetized Shock Experiment (MSX) at Los Alamos National Laboratory was built to investigate the physics of high-Alfvénic, supercritical, magnetized shocks through the acceleration and subsequent stagnation of a Field Reversed Configuration (FRC) plasmoid against a magnetic mirror and/or plasma target. An array of high-bandwidth, multi-axis, robust, internal magnetic probes has been constructed to characterize flux compression ratios, instability formation, and turbulent macro-scale features of the post-shock plasma. The mirror magnet is mounted on a linear translation stage, providing a capability to axially move the shock layer through the probe field of view. An independent, external probe array also provides conventional information on the FRC shape, velocity, and total pressure during the formation and acceleration phases. Probe design, characterization, configuration, and initial results are presented. This work is supported by the DOE OFES and NNSA under LANS contract DE-AC52-06NA25369. LA-UR-13-25189.

Introduction to D-He(3) fusion reactors

NASA Astrophysics Data System (ADS)

Vlases, G. C.; Steinhauer, L. C.

1989-07-01

A review and evaluation of D-He(3) fusion reactor technology is presented. The advantages and disadvantages of the D-He(3) and D-T reactor cycles are outlined and compared. In addition, the general design features of D-He(3) tokamaks and field reversed configuration (FRC) reactors are described and the relative merits of each are compared. It is concluded that both tokamaks and FRC's offer certain advantages, and that the ultimate decision as to which to persue for terrestrial power generation will depend heavily on how the physics performance of each of them develops over the next few years. It is clear that the D-He(3) fuel cycle offers marked advantages over the D-T cycle. Although the physics requirements for D-He(3) are more demanding, the overwhelming advantages resulting from the two order of magnitude reduction of neutron flux are expected to lead to a shorter time to commercialization than for the D-T cycle.

Absolute calibration of neutron detectors on the C-2U advanced beam-driven FRC.

PubMed

Magee, R M; Clary, R; Korepanov, S; Jauregui, F; Allfrey, I; Garate, E; Valentine, T; Smirnov, A

2016-11-01

In the C-2U fusion energy experiment, high power neutral beam injection creates a large fast ion population that sustains a field-reversed configuration (FRC) plasma. The diagnosis of the fast ion pressure in these high-performance plasmas is therefore critical, and the measurement of the flux of neutrons from the deuterium-deuterium (D-D) fusion reaction is well suited to the task. Here we describe the absolute, in situ calibration of scintillation neutron detectors via two independent methods: firing deuterium beams into a high density gas target and calibration with a 2 × 10 7 n/s AmBe source. The practical issues of each method are discussed and the resulting calibration factors are shown to be in good agreement. Finally, the calibration factor is applied to C-2U experimental data where the measured neutron rate is found to exceed the classical expectation.

Mobilisation of traffic-derived trace metals from road corridors into coastal stream and estuarine sediments, Cairns, northern Australia

NASA Astrophysics Data System (ADS)

Pratt, C.; Lottermoser, B. G.

2007-04-01

This investigation revealed the presence of traffic-derived metals within road, stream and estuarine sediments collected from a coastal catchment, northern Australia. Studied road sediments displayed variable total metal concentrations (median Cd, Cu, Pb, Pd, Pt, Ni and Zn values: 0.19, 42.6, 67.5, 0.064, 0.104, 36.7 and 698 mg/kg, respectively). The distinctly elevated Zn values are due to abundant tyre rubber shreds (as verified by SEM-EDS and correlation analysis). By comparison to the road sediments, background stream sediments taken upstream from roads have relatively low median Pb, Pd, Pt and Zn concentrations (7.3 mg/kg Pb, 0.01 mg/kg Pd, 0.012 mg/kg Pt, 62 mg/kg Zn). Stream and estuarine sediment samples collected below roads have median values of 21.8 mg/kg Pb, 0.014 mg/kg Pd, 0.021 mg/kg Pt and 71 mg/kg Zn, and exhibit 207Pb/206Pb and 208Pb/206Pb ratios that appear on a mixing line between the isotopically distinct background stream sediments and the road sediments. Thus, mobilisation of dusts and sediments from road surfaces has resulted in relatively elevated Pb, Pd, Pt and Zn concentrations and non-radiogenic Pb isotope ratios in local coastal stream and estuarine sediments. The investigation demonstrates that traffic-derived metals enter coastal stream and estuary sediments at the fringe of the Great Barrier Reef lagoon.

Geochemical background and ecological risk of heavy metals in surface sediments from the west Zhoushan Fishing Ground of East China Sea.

PubMed

Xu, Gang; Liu, Jian; Pei, Shaofeng; Hu, Gang; Kong, Xianghuai

2015-12-01

Surface sediment grain size as well as the spatial distribution, pollution status, and source identification of heavy metals in the west Zhoushan Fishing Ground (ZFG) of the East China Sea were analyzed to study the geochemical background concentrations of heavy metals and to assess their potential ecological risk. Our results show that surface sediments in the eastern part of study area were mainly composed of sand-sized components. Spatial distributions of heavy metals were mainly controlled by grain size and terrigenous materials, and their concentrations in the coarsest grain sediments formed primarily during the Holocene transgressive period could represent the element background values of our study area. Contamination factor suggests that there was no pollution of Pb, Zn, and Cr generally in our study area and slight pollution of Cu, Cd, and As (especially Cu) at some stations. In addition, ecological harm coefficient indicates that the ecological risk of each heavy metal, except for Cd, at two stations was low as well. These results are consistent with the pollution load index and ecological risk index, which suggest both the overall level of pollution and the overall ecological risk of six studied metals in sediment were relatively low in our study area. Enrichment factor indicates that the heavy metals came mostly from the natural source. Summarily, the quality level of sediment in our study area was relatively good, and heavy metals in sediments could not exert threat to aquatic lives in the ZFG until now.

Residual monomers and degree of conversion of partially bioresorbable fiber-reinforced composite.

PubMed

Väkiparta, Marju; Puska, Mervi; Vallittu, Pekka K

2006-01-01

The aim of this study was to evaluate the total quantity of residual monomer (bis-phenyl glycidyl dimethacrylate, i.e. Bis-GMA, and triethylene glycol dimethacrylate, i.e. TEGDMA), residual monomer release into water and the degree of monomer conversion (DC%) of glass fiber-reinforced composites (FRC) with a partially bioresorbable polymer matrix. Another aim was to find out whether the curing mode affects the quantity of residual monomer and degree of conversion. Glass fibers were preimpregnated with a bioresorbable poly(hydroxyproline) amide and non-resorbable Bis-GMA-TEGDMA resin system. Specimens were immersed in water for 1, 3 or 7 days (37 degrees C) to determine the quantity of leached residual monomers, or in the solvent tetrahydrofuran for 3 days to determine the total quantity of residual monomers by high performance liquid chromatography. DC% was measured by Fourier transform infrared spectroscopy. The quantity of residual monomer of the specimens decreased when the specimens contained glass fibers, and/or poly(hydroxyproline) amide, and/or when it was post-cured. The majority of the residual monomers were leached out during the first 24 h of immersion in water. The DC% of the specimens increased when post-cured. Also glass fibers in the composite increased the DC% in contrast to Bis-GMA-TEGDMA resin only. In conclusion, use of poly(hydroxyproline) amide as a sizing of the glass fibers in FRC does not increase the quantity of residual monomers. These results suggest that this new kind of partially bioresorbable FRC has potential for biomedical applications.

Comparing de novo genome assembly: the long and short of it.

PubMed

Narzisi, Giuseppe; Mishra, Bud

2011-04-29

Recent advances in DNA sequencing technology and their focal role in Genome Wide Association Studies (GWAS) have rekindled a growing interest in the whole-genome sequence assembly (WGSA) problem, thereby, inundating the field with a plethora of new formalizations, algorithms, heuristics and implementations. And yet, scant attention has been paid to comparative assessments of these assemblers' quality and accuracy. No commonly accepted and standardized method for comparison exists yet. Even worse, widely used metrics to compare the assembled sequences emphasize only size, poorly capturing the contig quality and accuracy. This paper addresses these concerns: it highlights common anomalies in assembly accuracy through a rigorous study of several assemblers, compared under both standard metrics (N50, coverage, contig sizes, etc.) as well as a more comprehensive metric (Feature-Response Curves, FRC) that is introduced here; FRC transparently captures the trade-offs between contigs' quality against their sizes. For this purpose, most of the publicly available major sequence assemblers--both for low-coverage long (Sanger) and high-coverage short (Illumina) reads technologies--are compared. These assemblers are applied to microbial (Escherichia coli, Brucella, Wolbachia, Staphylococcus, Helicobacter) and partial human genome sequences (Chr. Y), using sequence reads of various read-lengths, coverages, accuracies, and with and without mate-pairs. It is hoped that, based on these evaluations, computational biologists will identify innovative sequence assembly paradigms, bioinformaticists will determine promising approaches for developing "next-generation" assemblers, and biotechnologists will formulate more meaningful design desiderata for sequencing technology platforms. A new software tool for computing the FRC metric has been developed and is available through the AMOS open-source consortium.

Light exaggerates apical hook curvature through phytochrome actions in tomato seedlings.

PubMed

Shichijo, Chizuko; Ohuchi, Hisako; Iwata, Naoko; Nagatoshi, Yukari; Takahashi, Miki; Nakatani, Eri; Inoue, Kentaroh; Tsurumi, Seiji; Tanaka, Osamu; Hashimoto, Tohru

2010-02-01

Contrary to the established notion that the apical hook of dark-grown dicotyledonous seedlings opens in response to light, we found in tomato (Solanum lycopersicum L.) that the apical hook curvature is exaggerated by light. Experiments with several tomato cultivars and phytochrome mutants, irradiated with red and far-red light either as a brief pulse (Rp, FRp) or continuously (Rc, FRc), revealed: the hook-exaggeration response is maximal at the emergence of the hypocotyl from the seed; the effect of Rp is FRp-reversible; fluence-response curves to a single Rp or FRp show an involvement of low and very low fluence responses (LFR, VLFR); the effect of Rc is fluence-rate dependent, but that of FRc is not; the phyA mutant (phyA hp-1) failed to respond to an Rp of less than 10(-2) micromol m(-2) and to an FRp of all fluences tested as well as to FRc, thus indicating that the hook-exaggeration response involves phyA-mediated VLFR. The Rp fluence-response curve with the same mutant also confirmed the presence of an LFR mediated by phytochrome(s) other than phyA, although the phyB1 mutant (phyB1 hp-1) still showed full response probably due to other redundant phytochrome species (e.g., phyB2). Simulation experiments led to the possible significance of hook exaggeration in the field that the photoresponse may facilitate the release of seed coat when seeds germinate at some range of depth in soil. It was also observed that seed coat and/or endosperm are essential to the hook exaggeration.

Frontal sinus revision rate after nasal polyposis surgery including frontal recess clearance and middle turbinectomy: A long-term analysis.

PubMed

Benkhatar, Hakim; Khettab, Idir; Sultanik, Philippe; Laccourreye, Ollivier; Bonfils, Pierre

2018-08-01

To determine the frontal sinus revision rate after nasal polyposis (NP) surgery including frontal recess clearance (FRC) and middle turbinectomy (MT), to search for predictive factors and to analyse surgical management. Longitudinal analysis of 153 patients who consecutively underwent bilateral sphenoethmoidectomy with FRC and MT for NP with a minimum follow-up of 7 years. Decision of revision surgery was made in case of medically refractory chronic frontal sinusitis or frontal mucocele. Univariate and multivariate analysis incorporating clinical and radiological variables were performed. The frontal sinus revision rate was 6.5% (10/153). The mean time between the initial procedure and revision surgery was 3 years, 10 months. Osteitis around the frontal sinus outflow tract (FSOT) was associated with a higher risk of frontal sinus revision surgery (p=0.01). Asthma and aspirin intolerance did not increase the risk, as well as frontal sinus ostium diameter or residual frontoethmoid cells. Among revised patients, 60% required multiple procedures and 70% required frontal sinus ostium enlargement. Our long-term study reports that NP surgery including FRC and MT is associated with a low frontal sinus revision rate (6.5%). Patients developing osteitis around the FSOT have a higher risk of frontal sinus revision surgery. As mucosal damage can lead to osteitis, FSOT mucosa should be preserved during initial NP surgery. However, as multiple procedures are common among NP patients requiring frontal sinus revision, frontal sinus ostium enlargement should be considered during first revision in the hope of reducing the need of further revisions. Copyright © 2018 Elsevier B.V. All rights reserved.

Effects of Offshore Oil Exploration and Development in the Alaskan Beaufort Sea: A Three-Decade Record for Sediment Metals.

PubMed

Trefry, John H; Neff, Jerry M

2018-06-19

Impacts from oil exploration, development and production in the Beaufort Sea, Alaska, are assessed using concentrations of metals in sediments collected during 2014-15, combined with a large dataset for 1985-2006. Concentrations of 7 (1980 s) or 17 (1999-2015) metals in 423 surface sediments from 134 stations, plus 563 samples from 30 cores were highly variable, primarily as a function of sediment granulometry with naturally greater metal concentrations in fine-grained, Al-rich sediment. Metals versus Al correlation plots were used to normalize metal concentrations and identify values significantly above background. Barium, Cr, Cu, Hg and Pb concentrations were above background, but variable, within 250 m of some offshore sites where drilling occurred between 1981-2001; these areas totaled <6 km 2 of 11,000 km 2 in the total lease area. Random and fixed sampling along the coastal Beaufort Sea from 1985-2015 yielded 40 positive anomalies for metals in surface sediments (∼0.8% of 5,082 data points). About 85% of the anomalies were from developed areas. Half the anomalies were for the five metals found enhanced near drilling sites. No metals concentrations, except As, exceeded accepted sediment quality criteria. Interannual shifts in metals values for surface sediments at inner shelf sites were common and linked to storm-induced transitions in granulometry; however, metal/Al ratios were uniform during these shifts. Sediment cores generally recorded centuries of background values, except for As, Fe and Mn. These three metals were naturally enriched in sediments from deeper water (>100 m) via diagenetic remobilization at sediment depths of 5-15 cm, upward diffusion, and precipitation in surface oxic layers. Minimal evidence for anthropogenic inputs of metals, except near some exploratory drilling sites, is consistent with extraction of most oil from land or barrier islands in the Alaskan Arctic and restricted offshore activity to date. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Monitoring of Hydrocarbons in Sediment and Biota Related to Oil and Gas Development in Near- and Off-Shore Areas of the Arctic Beaufort Sea, Alaska

NASA Astrophysics Data System (ADS)

Durell, G.; Hardin, J.; Libby, S.

2016-02-01

There is increasing interest in extracting oil and gas from offshore environments of Alaska. The Arctic Nearshore Impact Monitoring in Development Area (ANIMIDA) project, started in 1999, has been producing information to evaluate potential effects of oil and gas activities in the Alaskan Beaufort Sea. ANIMIDA was preceded by the Beaufort Sea Monitoring Program. Monitoring has mostly been in pre-drilling locations, but also during development and production periods. Surveys were conducted to assess bottom sediment, sediment cores, suspended sediment, and biota for polycyclic aromatic hydrocarbons (PAH), saturated hydrocarbons, biological and petroleum markers, and geophysical parameters. The concentrations measured in sediments and biota were at or near background throughout most of the Beaufort Sea. There were no significant differences between exploration, production, and background locations, and the concentrations were consistently below those of ecological concern. For instance, TPAH in sediment ranged from below 100 to about 1,000 µg/kg and were controlled primarily by sediment characteristics (e.g., grain size and organic carbon). Hydrocarbons in sediments were from petrogenic, pyrogenic, and biogenic sources. Small areas with indications of input of anthropogenic chemicals were identified by sensitive diagnostic analysis techniques and are possibly associated with historic exploratory drilling and vessels. Sediment cores indicate a uniform historical deposition of hydrocarbons, although some evidence of past drilling activities were observed. Fish, amphipods, and clams contained background levels of hydrocarbons and showed no evidence of effects from accumulation of contaminants; TPAH concentrations were below 100 µg/kg in most biota. Noteworthy interannual fluctuations were observed for PAH concentrations in sediment and biota, likely due to winnowing of sediment fines by large storms and annual variations in river discharges. Significant natural sources were identified; rivers deliver about 80% of the annual suspended solids to Beaufort Sea within a 2-3 week period each spring with significant input of hydrocarbons from terrestrial sources. The ANIMIDA project has provided monitoring information that can confidently be used for future environmental management.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rognlien, T. D.; Cohen, B. I.

This report describes work performed by LLNL to model the behavior and performance of a reverse-field configuration (FRC) type of plasma device as a plasma thruster as summarized by Razin et al. [1], which also describes the MNX device at PPPL used to study this concept.

The effect of box preparation on the strength of glass fiber-reinforced composite inlay-retained fixed partial dentures.

PubMed

Ozcan, Mutlu; Breuklander, Marijn H; Vallittu, Pekka K

2005-04-01

Nonstandardized box dimensions for inlay-retained fixed partial dentures (FPDs) may result in uneven distribution of the forces on the connector region of such restorations. The objective of this in vitro study was to evaluate the effect of box dimensions on the initial and final failure strength of inlay-retained fiber-reinforced composite (FRC) FPDs. Twenty-one inlay-retained FPDs were prepared using FRC (everStick) frameworks with unidirectional fiber reinforcement between mandibular first premolars and first molars. Boxes were prepared using conventional inlay burs (Cerinlay), and small and large ultrasonic tips (SONICSYS approx). Box dimensions were measured after preparation with a digital micrometer. All restorations were subjected to thermal cycling (6000 cycles, 5 degrees C-55 degrees C). Fracture testing was performed in a universal testing machine (1 mm/min). Acoustic emission signals were monitored during loading of the specimens. Initial and final fracture strength values (2-way ANOVA, Bonferroni post hoc tests, alpha =.05) and failure types (Fisher exact test) were statistically compared for each group. Significant differences (P =.0146 and P =.0086) were observed between the groups in the dimensions of the boxes prepared using conventional burs buccolingually (2.8-3.0 mm in molars, 3.1-4.3 mm in premolars) and the small size (2.5-2.9, 2.9-3.8 mm) or large size (2.6-3.8, 3.2-4.9 mm) ultrasonic tips for the premolars and the molars, respectively. No significant differences were found at the initial and final failures between the conventionally prepared group (842 +/- 267 N, 1161 +/- 428 N) and those prepared with either small (1088 +/- 381 N, 1320 +/- 380 N) or large ultrasonic tips (1070 +/- 280 N, 1557 +/- 321 N), respectively. The failure analysis demonstrated no significant difference in failure types but predominant delamination of the veneering resin (85%) in all experimental groups. According to acoustic emission tests, a higher energy level was required for final failure of the FRC FPDs with boxes finished using small ultrasonic tips. Standardized box dimensions showed no significant effect on fracture strength at either initial or final failure of the fiber-reinforced FPDs. The FRC FPDs with boxes refined with small ultrasonic burs required a greater energy level before failure. The type of failure observed after the fracture tests was primarily delamination of the veneering resin.

Concentrations of heavy metals in sediment and organisms during a harmful algal bloom (HAB) at Kun Kaak Bay, Sonora, Mexico.

PubMed

García-Hernández, Jaqueline; García-Rico, Leticia; Jara-Marini, Martin E; Barraza-Guardado, Ramón; Hudson Weaver, Amy

2005-07-01

In early April 2003, fishermen from Kino Bay Sonora alerted us about a massive die-off of fish and mollusks occurring at Kun Kaak Bay. Phytoplankton samples taken on 17 May 2003 reported the presence of a harmful algal bloom composed of Chatonella marina, Chatonella cf. ovata, Gymnodinium catenatum and Gymnodinium sanguineum. On 22 of May, we collected samples of water, sediment and organisms at the affected area. Physicochemical parameters and nutrients were measured in water samples from different depths. Sediment and benthic organisms were analyzed for Cd, Cu, Zn, Pb and Hg. We found concentrations of heavy metals higher than background levels for this area. Cadmium and Lead concentrations in sediment from the HAB area were up to 6x greater than background levels and Cd in mollusks was 8x greater than regulations allow. A relationship between elevated Cd and Pb concentrations in sediment and the survival of toxic dinoflagellates is suspected.

Monitoring heavy metal concentrations in the sediments of the Moskva and Oka River system- Results of the Volga-Rhine-Project

NASA Astrophysics Data System (ADS)

Andresen, Höpke

2010-05-01

In the course of the Volga-Rhine-Project sediment, water and pore water samples were collected on the Volga as well as the Moskva and Oka river systems. The sampling area discussed here is located south east of the city of Moscow. Sediment samples were taken along the Moskva River between Moscow and the city of Kolomna, which is approximately 100 km to the southeast of Moscow and in the Oka River close to the confluence with the Moskva River (Kolomna). The first sampling campaign in this region took place in 1993, followed by further sampling in 1997 and 2007. For evaluation of sediment quality classification systems are often used. The geo-accumulation index proposed by Mueller (1979) is a classification system which consists of seven classes given by the following expression: I = log2×Cn- geo 1.5×Bn Where Cn = measured concentration; Bn = background value (Turekian & Wedepol 1961) of element n and 1.5 = background matrix correction factor. The geo-accumulation index consists of seven grades (0-6) which indicate the enrichment of an element compared to the background value. These grades range from 'not polluted' to 'very strongly polluted'. Another possibility to express sediment contamination is to evaluate the effects on the ecosystem. The lowest effect level (LEL) gives the concentrations of the heavy metals in sediment below which no effect on the majority of the sediment dwelling organisms is expected. The probable effect level (PEL) represents the concentration of heavy metals above which the organisms frequently will show adverse effects. Both of these approaches were used to evaluate the results of the Volga-Rhine-Project. In the last two decades the concentrations of heavy metals in the sediments decreased by up to 60%. In 1993 sediments revealed high concentrations of several heavy metals such as chromium, cadmium, lead, zinc, arsenic, nickel and cobalt, whereas in 2007 only two sediment samples were classified as 'very strongly polluted' regarding lead and cadmium concentrations. Additionally six other sediment samples were found to be 'strongly polluted' with cadmium, zinc and lead, respectively. Using the ecotoxicological approach on the sediments, chromium, cadmium and zinc are above the PEL, whereas the content of lead exceeds the LEL. Thus, these metals may still cause toxic effects on the fresh water system. Although the input of heavy metals into the river systems has clearly decreased during the last 20 years, there are still some locations where high concentrations of heavy metals are found, suggesting point sources. Especially cadmium still shows significantly higher concentrations than the background value in the entire sampling area. There are even two sampling points where the cadmium concentrations reach approximately 100x the background value. To determine the temporal variation of the heavy metal input, sediment cores were taken. Heavy metal concentrations increase with depth in the cores and show a maximum at a depth of about 35-40 cm. Some part of this increase may be a result of early diagenesis as well as a result of reduced heavy metal input. The nature of the decline of the heavy metal concentrations is still in progress. Despite all the improvements achieved in environmental protection in Russia, still some problems have to be addressed. Especially in urban areas like the Moscow region the number and the size of illegal dump sites is increasing dramatically, leading to strong inputs of heavy metals and other pollutants into the river systems, with consequences for the sensitive eco systems.

Sedimentation Effects on the Water Supply of APG

DTIC Science & Technology

2009-05-07

THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Background  The APG (South) Water Treatment Plant ( WTP ...low flow (15.6 cfs)  Typically during Maryland summers drought conditions prevent water uptake Background Cont’d  In 2007 the WTP was forced to shut...around the WTP intake  Will decrease particulate matter in the intake water  Will prevent sedimentation from completely blocking flow to the water

Constitutive modeling of fiber-reinforced cement composites

NASA Astrophysics Data System (ADS)

Boulfiza, Mohamed

The role of fibers in the enhancement of the inherently low tensile stress and strain capacities of fiber reinforced cementitious composites (FRC) has been addressed through both the phenomenological, using concepts of continuum damage mechanics, and micro-mechanical approaches leading to the development of a closing pressure that could be used in a cohesive crack analysis. The observed enhancements in the matrix behavior is assumed to be related to the ability of the material to transfer stress across cracks. In the micromechanics approach, this is modeled by the introduction of a nonlinear closing pressure at the crack lips. Due to the different nature of cracking in the pre-peak and post peak regimes, two different micro-mechanical models of the cohesive pressure have been proposed, one for the strain hardening stage and another for the strain softening regime. This cohesive pressure is subsequently incorporated into a finite element code so that a nonlinear fracture analysis can be carried out. On top of the fact that a direct fracture analysis has been performed to predict the response of some FRC structural elements, a numerical procedure for the homogenization of FRC materials has been proposed. In this latter approach, a link is established between the cracking taking place at the meso-scale and its mechanical characteristics as represented by the Young's modulus. A parametric study has been carried out to investigate the effect of crack patterning and fiber volume fractions on the overall Young's modulus and the thermodynamic force associated with the tensorial damage variable. After showing the usefulness and power of phenomenological continuum damage mechanics (PCDM) in the prediction of ERC materials' response to a stimuli (loading), a combined PCDM-NLFMsp1 approach is proposed to model (predict, forecast) the complete response of the composite up to failure. Based on experimental observations, this approach assumes that damage mechanics which predicts a diffused damage is more appropriate in the pre-peak regime whereas, NLFM is more suitable in the post-peak stage where the opening and propagation of a major crack will control the response of the material and not a deformation in a continuum sense as opposed to the pre-cracking zone. Tensile and compressive tests have been carried out for the sole purpose of calibrating the constitutive models proposed and/or developed in this thesis for FRC materials. The suitability of the models in predicting the response of different structural members has been performed by comparing the models' forecasts with experimental results carried out by the author, as well as experimental results from the literature. The different models proposed in this thesis have the possibility to account for the presence of fibers in the matrix, and give fairly good results for both high fiber volume fractions (vsb{f}≥2%) and low fiber volume fractions (vsb{f}<2%). Use of interface elements in a finite element code has been shown to be a powerful tool in analyzing the behavior of concrete substrate-FRC repair materials by the introduction of a zero thickness layer of interface elements to account for the interface properties which usually control the effectiveness of the repair material. ftnsp1NLFM: Non Linear Fracture Mechanics.

RF Plasma Heating in the PFRC-2 Device: Motivation, Goals and Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cohen, S.; Brunkhorst, C.; Glasser, A.

2011-12-23

The motivation for using radio frequency, odd-parity rotating magnetic fields for heating field-reversed-configuration (FRC) plasmas is explained. Calculations are presented of the expected electron and ion temperatures in the PFRC-2 device, currently under construction.

[Study on trace elements of lake sediments by ICP-AES and XRF core scanning].

PubMed

Cheng, Ai-Ying; Yu, Jun-Qing; Gao, Chun-Liang; Zhang, Li-Sha; He, Xian-Hu

2013-07-01

It is the first time to study sediment of Toson lake in Qaidam Basin. Trace elements including Cd, Cr, Cu, Zn and Pb in lake sediment were measured by ICP-AES method, studied and optimized from different resolution methods respectively, and finally determined a optimum pretreatment system for sediment of Toson lake, namely, HCl-HNO3-HF-HClO4-H2O2 system in the proportions of 5 : 5 : 5 : 1 : 1 was determined. At the same time, the data measured by XRF core scanning were compared, the use of moisture content correction method was analyzed, and the influence of the moisture content on the scanning method was discussed. The results showed that, compared to the background value, the contents of Cd and Zn were a little higher, the content of Cr, Cu and Pb was within the background value limits. XRF core scanning was controlled by sediment elements as well as water content in sediment to some extent. The results by the two methods showed a significant positive correlation, with the correlation coefficient up to 0.673-0.925, and they have a great comparability.

Mercury speciation in sediments at a municipal sewage sludge marine disposal site.

PubMed

Shoham-Frider, E; Shelef, G; Kress, N

2007-12-01

Mercury speciation was performed in excess activated sewage sludge (ASS) and in marine sediments collected at the AAS disposal site off the Mediterranean coast of Israel in order to characterize the spatial and vertical distribution of different mercury species and assess their environmental impact. Total Hg (HgT) concentrations ranged between 0.19 and 1003ng/g at the polluted stations and 5.7 and 72.8ng/g at the background station, while the average concentration in ASS was 1181+/-273ng/g. Only at the polluted stations did HgT concentrations decrease exponentially with sediment depth, reaching background values at 16-20cm, the vertical distribution resulting from mixing of natural sediment with ASS solids and bioturbation by large populations of polycheates. Average Methyl Hg (MeHg) concentration in ASS was 39.7+/-7.1ng/g, ca. 3% of the HgT concentration, while the background concentrations ranged between 0.1 and 0.61ng/g. MeHg concentrations in surficial polluted sediments were 0.7-5.9ng/g (ca. 0.5% of the HgT) and decreased vertically, similar to HgT. A positive correlation between MeHg and Hg only at the polluted stations, higher MeHg concentrations at the surface of the sediment and not below the redoxline, and no seasonality in the concentrations suggest that the MeHg originated from the ASS and not from in situ methylation. By doing selective extractions, we found that ca. 80% of the total Hg in ASS and polluted sediments was strongly bound to amorphous organo-sulfur and to inorganic sulfide species that are not bioavailable. The fractions with potential bioaccessible Hg had maximal concentrations in the range in which biotic effects should be expected. Therefore, although no bioaccumulation was found in the biota in the area, the concentration in the polluted sediments are not negligible and should be carefully monitored.

Improved CT-based estimate of pulmonary gas trapping accounting for scanner and lung-volume variations in a multicenter asthmatic study.

PubMed

Choi, Sanghun; Hoffman, Eric A; Wenzel, Sally E; Castro, Mario; Lin, Ching-Long

2014-09-15

Lung air trapping is estimated via quantitative computed tomography (CT) using density threshold-based measures on an expiration scan. However, the effects of scanner differences and imaging protocol adherence on quantitative assessment are known to be problematic. This study investigates the effects of protocol differences, such as using different CT scanners and breath-hold coaches in a multicenter asthmatic study, and proposes new methods that can adjust intersite and intersubject variations. CT images of 50 healthy subjects and 42 nonsevere and 52 severe asthmatics at total lung capacity (TLC) and functional residual capacity (FRC) were acquired using three different scanners and two different coaching methods at three institutions. A fraction threshold-based approach based on the corrected Hounsfield unit of air with tracheal density was applied to quantify air trapping at FRC. The new air-trapping method was enhanced by adding a lung-shaped metric at TLC and the lobar ratio of air-volume change between TLC and FRC. The fraction-based air-trapping method is able to collapse air-trapping data of respective populations into distinct regression lines. Relative to a constant value-based clustering scheme, the slope-based clustering scheme shows the improved performance and reduced misclassification rate of healthy subjects. Furthermore, both lung shape and air-volume change are found to be discriminant variables for differentiating among three populations of healthy subjects and nonsevere and severe asthmatics. In conjunction with the lung shape and air-volume change, the fraction-based measure of air trapping enables differentiation of severe asthmatics from nonsevere asthmatics and nonsevere asthmatics from healthy subjects, critical for the development and evaluation of new therapeutic interventions. Copyright © 2014 the American Physiological Society.

Improved CT-based estimate of pulmonary gas trapping accounting for scanner and lung-volume variations in a multicenter asthmatic study

PubMed Central

Choi, Sanghun; Hoffman, Eric A.; Wenzel, Sally E.; Castro, Mario

2014-01-01

Lung air trapping is estimated via quantitative computed tomography (CT) using density threshold-based measures on an expiration scan. However, the effects of scanner differences and imaging protocol adherence on quantitative assessment are known to be problematic. This study investigates the effects of protocol differences, such as using different CT scanners and breath-hold coaches in a multicenter asthmatic study, and proposes new methods that can adjust intersite and intersubject variations. CT images of 50 healthy subjects and 42 nonsevere and 52 severe asthmatics at total lung capacity (TLC) and functional residual capacity (FRC) were acquired using three different scanners and two different coaching methods at three institutions. A fraction threshold-based approach based on the corrected Hounsfield unit of air with tracheal density was applied to quantify air trapping at FRC. The new air-trapping method was enhanced by adding a lung-shaped metric at TLC and the lobar ratio of air-volume change between TLC and FRC. The fraction-based air-trapping method is able to collapse air-trapping data of respective populations into distinct regression lines. Relative to a constant value-based clustering scheme, the slope-based clustering scheme shows the improved performance and reduced misclassification rate of healthy subjects. Furthermore, both lung shape and air-volume change are found to be discriminant variables for differentiating among three populations of healthy subjects and nonsevere and severe asthmatics. In conjunction with the lung shape and air-volume change, the fraction-based measure of air trapping enables differentiation of severe asthmatics from nonsevere asthmatics and nonsevere asthmatics from healthy subjects, critical for the development and evaluation of new therapeutic interventions. PMID:25103972

Influence of Laser Activated Irrigation with two Erbium Lasers on Bond Strength of Inidividually Formed Fiber Reinforced Composite Posts to Root Canal Dentin.

PubMed

Parčina, Ivana; Amižić; Miletić, Ivana; Ionescu, Andrei C; Brambilla, Eugenio; Gabrić, Dragana; Baraba, Anja

2016-12-01

The aim of this in vitro study was to investigate the effect of laser activated irrigation (LAI) using two erbium lasers on bond strength of individually formed fiber-reinforced composite (FRC) posts to root canal dentin. Twenty-seven single-rooted human teeth were endodontically treated and after post space preparation divided into three groups (n=9 per group), according to the pre-treatment of post space preparation: 1) Conventional syringe irrigation (CSI) and saline; 2) Er.YAG photon-induced photoacoustic streaming (PIPS) technique and saline; 3) Er,Cr:YSGG activated irrigation with RFT2 tip. Two specimens from each group were used for SEM analysis. The remaining specimens (n=7 per group) received individually formed FRC post, everStick POST, luted with self-adhesive cement, G-CEM LinkAce. After cementation, the roots were perpendicularly sectioned into 1 mm thin sections and a push-out test was carried out (0.5 mm/min). The data were calculated as megapascals and were log transformed and statistically analysed using one-way ANOVA at the level of significance set at 5%. In the control group, the smear layer was still present. In the Er:YAG group, the smear layer was removed. In the Er,Cr:YSGG group, the smear layer was partially removed. The Er,Cr:YSGG group achieved the highest bond strength values, followed by the control group and then the Er:YAG group, but no statistically significant difference was found in bond strength values in the tested group of post space pretreatment (p=0.564). LAI using two erbium lasers, with PIPS or RFT2 tip, did not affect the bond strength of individually formed FRC posts to root canal dentin.

Influence of heart failure on resting lung volumes in patients with COPD

PubMed Central

de Souza, Aline Soares; Sperandio, Priscila Abreu; Mazzuco, Adriana; Alencar, Maria Clara; Arbex, Flávio Ferlin; de Oliveira, Mayron Faria; O'Donnell, Denis Eunan; Neder, José Alberto

2016-01-01

ABSTRACT Objective: To evaluate the influence of chronic heart failure (CHF) on resting lung volumes in patients with COPD, i.e., inspiratory fraction-inspiratory capacity (IC)/TLC-and relative inspiratory reserve-[1 − (end-inspiratory lung volume/TLC)]. Methods: This was a prospective study involving 56 patients with COPD-24 (23 males/1 female) with COPD+CHF and 32 (28 males/4 females) with COPD only-who, after careful clinical stabilization, underwent spirometry (with forced and slow maneuvers) and whole-body plethysmography. Results: Although FEV1, as well as the FEV1/FVC and FEV1/slow vital capacity ratios, were higher in the COPD+CHF group than in the COPD group, all major "static" volumes-RV, functional residual capacity (FRC), and TLC-were lower in the former group (p < 0.05). There was a greater reduction in FRC than in RV, resulting in the expiratory reserve volume being lower in the COPD+CHF group than in the COPD group. There were relatively proportional reductions in FRC and TLC in the two groups; therefore, IC was also comparable. Consequently, the inspiratory fraction was higher in the COPD+CHF group than in the COPD group (0.42 ± 0.10 vs. 0.36 ± 0.10; p < 0.05). Although the tidal volume/IC ratio was higher in the COPD+CHF group, the relative inspiratory reserve was remarkably similar between the two groups (0.35 ± 0.09 vs. 0.44 ± 0.14; p < 0.05). Conclusions: Despite the restrictive effects of CHF, patients with COPD+CHF have relatively higher inspiratory limits (a greater inspiratory fraction). However, those patients use only a part of those limits, probably in order to avoid critical reductions in inspiratory reserve and increases in elastic recoil. PMID:27832235

Lung volumes during sustained microgravity on Spacelab SLS-1

NASA Technical Reports Server (NTRS)

Elliott, Ann R.; Prisk, G. Kim; Guy, Harold J. B.; West, John B.

1994-01-01

Gravity is known to influence the mechanical behavior of the lung and chest wall. However, the effect of sustained microgravity (microgravity) on lung volumes has not been reported. Pulmonary function tests were performed by four subjects before, during, and after 9 days of microgravity exposure. Ground measurements were made in standing and supine postures. Tests were performed using a bag-in-box-and-flowmeter system and a respiratory mass spectrometer. Measurements included functional residual capacity (FRC), expiratory reserve volume (ERV), residual volume (RV), inspiratory and expiratory vital capacities (IVC and EVC), and tidal volume (V9sub T)). Total lung capacity (TLC) was derived from the measured EVC and RV values. With preflight standing values as a comparison, FRC was significantly reduced by 15% (approximately 500 ml) in microgravity and 32% in the supine posture. ERV was reduced by 10 - 20% in microgravity and decreased by 64% in the supine posture. RV was significantly reduced by 18% (310 ml) in microgravity but did not significantly change in the supine posture compared with standing. IVC and EVC were slightly reduced during the first 24 h of microgravity but returned to 1-G standing values within 72 h of microgravity exposure. IVC and EVC in the supine posture were significantly reduced by 12% compared with standing. During microgravity, V(sub T) decreased by 15% (approximately 90 ml), but supine V(sub T) was unchanged compared with preflight standing values. TLC decreased by approximately 8% during microgravity and in the supine posture compared with preflight standing. The reductions in FRC, ERV, and RV during microgravity are probably due to the cranial shift of the diaphragm, an increase in intrathoracic blood volume, and more uniform alveolar expansion.

A Novel Physiological Investigation of the Functional Residual Capacity by the Bias Flow Nitrogen Washout Technique in Infants

PubMed Central

Morris, Mohy G.

2011-01-01

Summary The dynamic functional residual capacity (FRCdyn), the lung volume most routinely measured in infants, is an unreliable volume landmark. In addition to the FRCdyn, we measured the (passive) static FRC (FRCst) by inducing a brief post-hyperventilation apnea (PHA) in 33 healthy infants aged 7.4–127.2 weeks. A commercial system for nitrogen (N2) washout to measure FRC, and a custom made system to monitor and record flow and airwayopening pressure signals in real-time were used in unison. Infants were manually hyperventilated to induce a PHA. After the last passive expiration, FRCst was estimated by measuring the volume of N2 expired after end-passive expiratory switching of the inspired gas from room air to 100% oxygen during the post-expiratory apneic pause. Repeatable intrasubject FRCst and FRCdyn measurements overlapped in most infants including the younger ones (P = 0.2839). Mean (95% confidence interval [CI]) FRCst was 21.1 (20.0–22.3), and error-corrected FRCdyn was 21.4 (20.4–22.4) ml/kg. Mean (washout time [t]) tFRCst was longer than tFRCdyn 60 sec (95% CI 55–65) versus 47 sec (95% CI 43–51) (P<0.0001). The FRC and washout time were dependent on body length, weight and age. We conclude that the FRCst is not different from the FRCdyn in infants. The FRCst is a reliable volume landmark because the PHA stabilizes the end-expiratory level by potentially abolishing the sedated infant’s breathing strategies. The FRCst lacks potential sources of errors and disadvantages associated with measuring the FRCdyn. The findings cast significant doubt on the traditional physiology of air trapping in healthy infants’ lungs. PMID:19499588

Sprinting performance on the Woodway Curve 3.0 is related to muscle architecture.

PubMed

Mangine, Gerald T; Fukuda, David H; Townsend, Jeremy R; Wells, Adam J; Gonzalez, Adam M; Jajtner, Adam R; Bohner, Jonathan D; LaMonica, Michael; Hoffman, Jay R; Fragala, Maren S; Stout, Jeffrey R

2015-01-01

To determine if unilateral measures of muscle architecture in the rectus femoris (RF) and vastus lateralis (VL) were related to (and predictive of) sprinting speed and unilateral (and bilateral) force (FRC) and power (POW) during a 30 s maximal sprint on the Woodway Curve 3.0 non-motorized treadmill. Twenty-eight healthy, physically active men (n = 14) and women (n = 14) (age = 22.9 ± 2.4 years; body mass = 77.1 ± 16.2 kg; height = 171.6 ± 11.2 cm; body-fa t = 19.4 ± 8.1%) completed one familiarization and one 30-s maximal sprint on the TM to obtain maximal sprinting speed, POW and FRC. Muscle thickness (MT), cross-sectional area (CSA) and echo intensity (ECHO) of the RF and VL in the dominant (DOM; determined by unilateral sprinting power) and non-dominant (ND) legs were measured via ultrasound. Pearson correlations indicated several significant (p < 0.05) relationships between sprinting performance [POW (peak, DOM and ND), FRC (peak, DOM, ND) and sprinting time] and muscle architecture. Stepwise regression indicated that POW(DOM) was predictive of ipsilateral RF (MT and CSA) and VL (CSA and ECHO), while POW(ND) was predictive of ipsilateral RF (MT and CSA) and VL (CSA); sprinting power/force asymmetry was not predictive of architecture asymmetry. Sprinting time was best predicted by peak power and peak force, though muscle quality (ECHO) and the bilateral percent difference in VL (CSA) were strong architectural predictors. Muscle architecture is related to (and predictive of) TM sprinting performance, while unilateral POW is predictive of ipsilateral architecture. However, the extent to which architecture and other factors (i.e. neuromuscular control and sprinting technique) affect TM performance remains unknown.

Lung volumes during sustained microgravity on Spacelab SLS-1.

PubMed

Elliott, A R; Prisk, G K; Guy, H J; West, J B

1994-10-01

Gravity is known to influence the mechanical behavior of the lung and chest wall. However, the effect of sustained microgravity (mu G) on lung volumes has not been reported. Pulmonary function tests were performed by four subjects before, during, and after 9 days of mu G exposure. Ground measurements were made in standing and supine postures. Tests were performed using a bag-in-box-and-flowmeter system and a respiratory mass spectrometer. Measurements included functional residual capacity (FRC), expiratory reserve volume (ERV), residual volume (RV), inspiratory and expiratory vital capacities (IVC and EVC), and tidal volume (VT). Total lung capacity (TLC) was derived from the measured EVC and RV values. With preflight standing values as a comparison, FRC was significantly reduced by 15% (approximately 500 ml) in mu G and 32% in the supine posture. ERV was reduced by 10-20% in mu G and decreased by 64% in the supine posture. RV was significantly reduced by 18% (310 ml) in mu G but did not significantly change in the supine posture compared with standing. IVC and EVC were slightly reduced during the first 24 h of mu G but returned to 1-G standing values within 72 h of mu G exposure. IVC and EVC in the supine posture were significantly reduced by 12% compared with standing. During mu G, VT decreased by 15% (approximately 90 ml), but supine VT was unchanged compared with preflight standing values. TLC decreased by approximately 8% during mu G and in the supine posture compared with preflight standing. The reductions in FRC, ERV, and RV during mu G are probably due to the cranial shift of the diaphragm, an increase in intrathoracic blood volume, and more uniform alveolar expansion.

Human Influences on Geomorphic Dynamics in Western Montana Gravel-Bed Rivers

NASA Astrophysics Data System (ADS)

Wilcox, A. C.

2016-12-01

Management of river ecosystems, river restoration, climate-change vulnerability assessments, and other applications require understanding of how current channel conditions and processes compare to historical ranges of variability. This is particularly true with respect to evaluation of sediment balances, including of whether and how current sediment supply compares to background conditions. In western Montana, management and restoration efforts are in some cases driven by the perception that anthropogenic activities have elevated sediment yields above background levels; human-induced erosional increases have been documented in certain environments, but empirical supporting evidence is lacking for western Montana rivers. Here, human-induced changes in channel form and in sediment balances, including flow, sediment supply, and erosion rates, are evaluated for rivers in western Montana, with a particular focus on the Clark Fork and Bitterroot Rivers. These rivers are characteristic of systems in the northern Rocky Mountains with gravel beds, historically wandering channel patterns, modest bed-material loads, and land uses including logging, mining, and agriculture. The Clark Fork is influenced by legacy mining-related sediments and associated contaminants, remediation efforts, and the 2008 removal of Milltown Dam. These influences have caused temporary shifts in sediment balances, but overall, sediment fluxes are modest (e.g., suspended sediment fluxes of 6 tonnes km-2 yr-1 at the USGS Turah gage). The Bitterroot River is influenced by a mix of glaciated and unglaciated landscapes with fire-dominated erosional regimes and larger sand supply than the Clark Fork, reflecting lithologic differences; erosion rates, and the imprint of anthropogenic activities on sediment dynamics, are being investigated. This work has implications for river restoration, including whether measures are needed to impose channel stability, and for evaluating how climate-change-induced changes in fire, runoff, and erosion will alter fluvial sediment balances.

High Fidelity Modeling of Field Reversed Configuration (FRC) Thrusters

DTIC Science & Technology

2015-10-01

dispersion depends on the Riemann solver • Variables are allowed to be discontinuous at the cell interfaces Advantages - Method is conservative...release; distribution unlimited Discontinuous Galerkin (2) • Riemann problems are solved at each interface to compute fluxes • The source of dissipation

Studies on Plasmoid Merging using Compact Toroid Injectors

NASA Astrophysics Data System (ADS)

Allfrey, Ian; Matsumoto, Tadafumi; Roche, Thomas; Gota, Hiroshi; Edo, Takahiro; Asai, Tomohiko; Sheftman, Daniel; Osin Team; Dima Team

2017-10-01

C-2 and C-2U experiments have used magnetized coaxial plasma guns (MCPG) to inject compact toroids (CTs) for refueling the long-lived advanced beam-driven field-reversed configuration (FRC) plasma. This refueling method will also be used for the C-2W experiment. To minimize momentum transfer from the CT to the FRC two CTs are injected radially, diametrically opposed and coincident in time. To improve understanding of the CT characteristics TAE has a dedicated test bed for the development of CT injectors (CTI), where plasmoid merging experiments are performed. The test bed has two CTIs on axis with both axial and transverse magnetic fields. The 1 kG magnetic fields, intended to approximate the magnetic field strength and injection angle on C-2W, allow studies of cross-field transport and merging. Both CTIs are capable of injecting multiple CTs at up to 1 kHz. The resulting merged CT lives >100 μs with a radius of 25 cm. More detailed results of CT parameters will be presented.

[Fracture strength of elastic and conventional fibre-reinforced composite intraradicular posts--an in vitro pilot study].

PubMed

Fráter, Mark; Forster, András; Jantyik, Ádám; Braunitzer, Gábor; Nagy, Katalin

2015-12-01

The purpose of this in vitro investigation was to evaluate the reinforcing effect of different fibre-reinforced composite (FRC) posts and insertion techniques in premolar teeth when using minimal invasive post space preparation. Thirty two extracted and endodontically treated premolar teeth were used and divided into four groups (n = 8) depending on the post used (Group 1-4). 1: one single conventional post, 2: one main conventional and one collateral post, 3: one flexible post, 4: one main flexible and one collateral post. After cementation and core build-up the specimens were submitted to static fracture toughness test. Fracture thresholds and fracture patterns were recorded and evaluated. The multi-post techniques (group 2 and 4) showed statistically higher fracture resistance compared to group one. Regarding fracture patterns there was no statistically significant difference between the tested groups. The application of multiple posts seems to be beneficial regarding fracture resistance independent from the used FRC post. Fracture pattern was not influenced by the elasticity of the post.

ECN-2301

NASA Image and Video Library

1969-09-10

The Hyper III was a low-cost test vehicle for an advanced lifting-body shape. Like the earlier M2-F1, it was a "homebuilt" research aircraft, i.e., built at the Flight Research Center (FRC), later redesignated the Dryden Flight Research Center. It had a steel-tube frame covered with Dacron, a fiberglass nose, sheet aluminum fins, and a wing from an HP-11 sailplane. Construction was by volunteers at the FRC. Although the Hyper III was to be flown remotely in its initial tests, it was fitted with a cockpit for a pilot. On the Hyper III's only flight, it was towed aloft attached to a Navy SH-3 helicopter by a 400-foot cable. NASA research pilot Bruce Peterson flew the SH-3. After he released the Hyper III from the cable, NASA research pilot Milt Thompson flew the vehicle by radio control until the final approach when Dick Fischer took over control using a model-airplane radio-control box. The Hyper III flared, then landed and slid to a stop on Rogers Dry Lakebed.

Reinforcing effects of different fibers on denture base resin based on the fiber type, concentration, and combination.

PubMed

Yu, Sang-Hui; Lee, Yoon; Oh, Seunghan; Cho, Hye-Won; Oda, Yutaka; Bae, Ji-Myung

2012-01-01

The aim of this study was to evaluate the reinforcing effects of three types of fibers at various concentrations and in different combinations on flexural properties of denture base resin. Glass (GL), polyaromatic polyamide (PA) and ultra-high molecular weight polyethylene (PE) fibers were added to heat-polymerized denture base resin with volume concentrations of 2.6%, 5.3%, and 7.9%, respectively. In addition, hybrid fiber-reinforced composite (FRC) combined with either two or three types of fibers were fabricated. The flexural strength, modulus and toughness of each group were measured with a universal testing machine at a crosshead speed of 5 mm/min. In the single fiber-reinforced composite groups, the 5.3% GL and 7.9% GL had the highest flexural strength and modulus; 5.3% PE was had the highest toughness. Hybrid FRC such as GL/PE, which showed the highest toughness and the flexural strength, was considered to be useful in preventing denture fractures clinically.

Issues with Strong Compression of Plasma Target by Stabilized Imploding Liner

NASA Astrophysics Data System (ADS)

Turchi, Peter; Frese, Sherry; Frese, Michael

2017-10-01

Strong compression (10:1 in radius) of an FRC by imploding liquid metal liners, stabilized against Rayleigh-Taylor modes, using different scalings for loss based on Bohm vs 100X classical diffusion rates, predict useful compressions with implosion times half the initial energy lifetime. The elongation (length-to-diameter ratio) near peak compression needed to satisfy empirical stability criterion and also retain alpha-particles is about ten. The present paper extends these considerations to issues of the initial FRC, including stability conditions (S*/E) and allowable angular speeds. Furthermore, efficient recovery of the implosion energy and alpha-particle work, in order to reduce the necessary nuclear gain for an economical power reactor, is seen as an important element of the stabilized liner implosion concept for fusion. We describe recent progress in design and construction of the high energy-density prototype of a Stabilized Liner Compressor (SLC) leading to repetitive laboratory experiments to develop the plasma target. Supported by ARPA-E ALPHA Program.

NIMROD simulations of the IPA FRC experiment

NASA Astrophysics Data System (ADS)

Milroy, Richard

2015-11-01

The IPA experiment created a high temperature plasma by merging and compressing supersonic θ-pinch formed FRCs. The NIMROD code has been used to simulate this process. These calculations include the θ-pinch formation and acceleration of two FRC's using the dynamic formation methodology, and their translation to a central compression chamber where they merge and are magnetically compressed. Transport coefficients have been tuned so simulation results agree well with experimental observation. The inclusion of the Hall term is essential for the FRCs merge quickly, as observed experimentally through the excluded flux profiles. The inclusion of a significant anisotropic viscosity is required for the excluded flux profiles to agree well with the experiment. We plan to extend this validation work using the new ARPA-E funded Venti experiment at Helion Energy in Redmond WA. This will be a very well diagnosed experiment where two FRCs merge (like the IPA experiment) and are then compressed to near-fusion conditions. Preliminary calculations with parameters relevant to this experiment have been made, and some numerical issues identified.

Optical diagnostics on the Magnetized Shock Experiment (MSX)

NASA Astrophysics Data System (ADS)

Boguski, J. C.; Weber, T. E.; Intrator, T. P.; Smith, R. J.; Dunn, J. P.; Hutchinson, T. M.; Gao, K. W.

2013-10-01

The Magnetized Shock Experiment (MSX) at Los Alamos National Laboratory was built to investigate the physics of high Alfvén Mach number, supercritical, magnetized shocks through the acceleration and subsequent stagnation of a Field Reversed Configuration (FRC) plasmoid against a magnetic mirror and/or plasma target. A suite of optical diagnostics has recently been fielded on MSX to characterize plasma conditions during the formation, acceleration, and stagnation phases of the experiment. CCD-backed streak and framing cameras, and a fiber-based visible light array, provide information regarding FRC shape, velocity, and instability growth. Time-resolved narrow and broadband spectroscopy provides information on pre-shock plasma temperature, impurity levels, shock location, and non-thermal ion distributions within the shock region. Details of the diagnostic design, configuration, and characterization will be presented along with initial results. This work is supported by the Center for Magnetic Self Organization, DoE OFES and NNSA under LANS contract DE-AC52-06NA25369. Approved for public release: LA-UR- 13-25190.

High sensitivity far infrared laser diagnostics for the C-2U advanced beam-driven field-reversed configuration plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, B. H., E-mail: bdeng@trialphaenergy.com; Beall, M.; Schroeder, J.

2016-11-15

A high sensitivity multi-channel far infrared laser diagnostics with switchable interferometry and polarimetry operation modes for the advanced neutral beam-driven C-2U field-reversed configuration (FRC) plasmas is described. The interferometer achieved superior resolution of 1 × 10{sup 16} m{sup −2} at >1.5 MHz bandwidth, illustrated by measurement of small amplitude high frequency fluctuations. The polarimetry achieved 0.04° instrument resolution and 0.1° actual resolution in the challenging high density gradient environment with >0.5 MHz bandwidth, making it suitable for weak internal magnetic field measurements in the C-2U plasmas, where the maximum Faraday rotation angle is less than 1°. The polarimetry resolution datamore » is analyzed, and high resolution Faraday rotation data in C-2U is presented together with direct evidences of field reversal in FRC magnetic structure obtained for the first time by a non-perturbative method.« less

Estimation of mercury background values in sediment and biota of the Bijagós archipelago, Guinea-Bissau.

PubMed

Coelho, J P; Monteiro, R J R; Catry, T; Lourenço, P M; Catry, P; Regalla, A; Catry, I; Figueira, P; Pereira, E; Vale, C; P Granadeiro, José

2016-10-15

This work evaluates the mercury (Hg) contamination status (sediments and biota) of the Bijagós archipelago, off the coast of Guinea-Bissau. Sediments exhibited very low concentrations (<1-12ngg(-1)), pointing to negligible sources of anthropogenic Hg in the region. Nevertheless, Hg is well correlated to the fine fraction, aluminium, and loss on ignition, indicating the effect of grain size and organic matter content on the presence of Hg in sediments. Mercury in the bivalves Tagelus adansoni and Senilia senilis did not vary considerably among sites, ranging within narrow intervals (0.09-0.12 and 0.12-0.14μgg(-1) (dry weight), respectively). Divergent substrate preferences/feeding tactics may justify slight differences between species. The value 11ngg(-1) is proposed as the sediment background concentration for this West-African coastal region, and concentrations within the interval 8-10ngg(-1) (wet weight) may be considered as reference range for S. senilis and T. adansoni in future monitoring studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Stream-sediment geochemistry in mining-impacted streams: Prichard, Eagle, and Beaver creeks, northern Coeur d'Alene Mining District, northern Idaho

USGS Publications Warehouse

Box, Stephen E.; Wallis, John C.; Briggs, Paul H.; Brown, Zoe Ann

2005-01-01

This report presents the results of one aspect of an integrated watershed-characterization study that was undertaken to assess the impacts of historical mining and milling of silver-lead-zinc ores on water and sediment composition and on aquatic biota in streams draining the northern part of the Coeur d?Alene Mining District in northern Idaho. We present the results of chemical analyses of 62 samples of streambed sediment, 19 samples of suspended sediment, 23 samples of streambank soil, and 29 samples of mine- and mill-related artificial- fill material collected from the drainages of Prichard, Eagle, and Beaver Creeks, all tributaries to the North Fork of the Coeur d?Alene River. All samples were sieved into three grain-size fractions (<0.063, 0.063?0.25, and 0.25?1.0 mm) and analyzed for 40 elements after four-acid digestion by inductively coupled plasma atomic-emission spectrometry and for mercury by continuous- flow cold-vapor atomic-absorption spectrometry in the U.S. Geological Survey laboratory in Denver, Colo. Historical mining of silver-lead-zinc ores in the headwater reaches of the Prichard Creek, Eagle Creek, and Beaver Creek drainages has resulted in enrichments of lead, zinc, mercury, arsenic, cadmium, silver, copper, cobalt, and, to a lesser extent, iron and manganese in streambed sediment. Using samples collected from the relatively unimpacted West Fork of Eagle Creek as representative of background compositions, streambed sediment in the vicinity of the mines and millsites has Pb and Zn contents of 20 to 100 times background values, decreasing to 2 to 5 times background values at the mouth of the each stream, 15 to 20 km downstream. Lesser enrichments (<10 times background values) of mercury and arsenic also are generally associated with, and decrease downstream from, historical silver-lead-zinc mining in the drainages. However, enrichments of arsenic and, to a lesser extent, mercury also are areally associated with the lode gold deposits along Prichard Creek near Murray, which were not studied here. Metal contents in samples of unfractionated suspended sediment collected during a high-flow event in April 2000 are generally similar to, but slightly higher than, those in the fine (<0.063- mm grain size) fraction of streambed sediment from the same sampling site. Although metal enrichment in streambed sediment typically begins adjacent to the mine portals and their associated mine-waste rock dumps, volumetrically larger inputs of metal-enriched materials were contributed by the ore-concentration millsites and their associated, more finely ground, more metal rich mill-tailings impoundments.

Mercury Geochemistry of Gold Placer Tailings, Sediments, Bedrock, and Waters in the Lower Clear Creek Area, Shasta County, California - Report of Investigations, 2001-2003

USGS Publications Warehouse

Ashley, Roger P.; Rytuba, James J.

2008-01-01

Clear Creek, one of the major tributaries of the upper Sacramento River, drains the eastern Trinity Mountains. Alluvial plain and terrace gravels of lower Clear Creek, at the northwest edge of the Sacramento Valley, contain placer gold that has been mined since the Gold Rush by various methods including hydraulic mining and dredging. In addition, from the 1950s to the 1980s aggregate-mining operations removed gravel from the lower Clear Creek flood plain. Since Clear Creek is an important stream for salmon production, a habitat restoration program is underway to repair damage from mining and improve conditions for spawning. This program includes moving dredge tailings to increase the area of spawning gravel and to fill gravel pits in the flood plain, raising the concern that mercury lost to these tailings in the gold recovery process may be released and become available to biota. The purposes of our study are to identify sources, transport, and dispersal of mercury in the lower Clear Creek area and identify environments in which bioavailable methylmercury is produced. Analytical data acquired include total mercury and methylmercury concentrations in sediments, tailings, and water. Mercury concentrations in bedrock and unmined gravels in and around the mined area are low and are taken to represent background concentrations. Bulk mercury values in placer mining tailings range from near-background in coarse dry materials to more than 40 times background in sands and silts exposed to mercury in sluices. Tailings are entrained in flood-plain sediments and active stream sediments; consequently, mercury concentrations in these materials range from background to about two to three times background. Mercury in sediments and tailings is associated with fine size fractions. The source of most of this mercury is historical gold mining in the Clear Creek watershed. Although methylmercury levels are low in most of these tailings and sediments, flood-plain sediment in shallow flood-plain ponds, tailings in a dredge pond, and active stream sediment in a Clear Creek backwater have elevated levels of methylmercury. Stream waters in the area show low mercury levels during both summer and winter base-flow conditions. During winter high flows total mercury increases by about one order of magnitude; this additional mercury is associated with suspended particulate material. Methylmercury is low in stream waters. Ponds in various environments generally have higher total mercury levels in waters than Clear Creek under base-flow conditions and higher methylmercury levels in both sediments and waters. Ponds are probably the main source of bioavailable mercury in the lower Clear Creek area. Several saline springs occur in the area. The saline waters are enriched in lithium, boron, and mercury, similar to connate waters that are expelled along thrust faults to the south on the west side of the Sacramento Valley. Saline springs may locally contribute some mercury to pond and drainage waters.

Regional geochemistry of metal-contaminated surficial sediments and seagrasses in upper Spencer Gulf, South Australia

NASA Astrophysics Data System (ADS)

Tiller, K. G.; Merry, R. H.; Zarcinas, B. A.; Ward, T. J.

1989-05-01

Surficial sediments, shallow sediment cores and seagrass samples were collected over an area of about 600 km 2 of upper Spencer Gulf, South Australia, adjacent to a major lead-zinc smelter. Regional variation in heavy metal contents was studied in relation to different pathways of contamination from the smelter complex, and geochemical association with natural constituents of the sediments. About 300 km 2 were contaminated to some extent. Areas of appreciable contamination (10 × background) were greatest for Cd and least for As, with Pb and Zn intermediate. Regional trends of heavy metals in the sediment reflected inputs of pollutants from both liquid effluents and atmospheric fallout, modified by tidal currents. Total accessions to Germein Bay were estimated to be at least 25 000 tonnes each of Pb and Zn and 500 tonnes of Cd and As. Arsenic differed both in its distribution with sediment depth and in its geochemical associations when compared to Pb, Zn and Cd. Correlation of Cd with the fine fraction (< 20 μm) permitted a normalization of data which accounted for marked regional variations in sediment grain size and provided a better basis of assessing the regional impact of pollution. Metal concentrations in Posidonia leaves were highly correlated with total and EDTA extractable metal concentrations in the sediments, and may provide a more sensitive indicator of metal dispersion. Background levels of metals in Posidonia were not found in our study area.

Effects of wind-wave disturbances on adsorption and desorption of tetracycline and sulfadimidine in water-sediment systems.

PubMed

Liao, Qianjiahua; Huang, Zheng; Li, Shu; Wang, Yi; Liu, Yuqing; Luo, Ran; Shang, Jingge

2018-05-28

Wind-wave disturbances frequently disperse sediment particles into overlying water, which facilitates the adsorption and desorption of contaminants in aquatic ecosystems. Tetracycline (TC) and sulfadimidine (SM2) are common antibiotics that are frequently found in aquatic environments. This study utilized microcosms, comprising sediment and water from Lake Taihu, China, to examine the adsorption and desorption of TC and SM2 under different wind-wave disturbances in a shallow lake environment. The adsorption experiments were conducted with three different concentrations (1, 5, 10 mg/L) of TC and SM2 in the overlying water, and two different (background and strong) wind-wave conditions for 72 h. Subsequently, four microcosms were employed in a 12-h desorption study. Analysis of adsorption progress showed that TC concentration in the overlying water decreased quickly, while SM2 remained almost constant. In the desorption experiments, SM2 released to the overlying water was an order of magnitude greater than TC. These results indicate that sediment particles strongly adsorb TC but weakly adsorb SM2. Compared to background conditions, the strong wind-wave conditions resulted in higher concentrations of TC and SM2 in sediment and facilitated their migration to deeper sediment during adsorption, correspondingly promoting greater release of TC and SM2 from sediment particles into the overlying water during desorption.

Identifying and Quantifying Chemical Forms of Sediment-Bound Ferrous Iron.

NASA Astrophysics Data System (ADS)

Kohler, M.; Kent, D. B.; Bekins, B. A.; Cozzarelli, I.; Ng, G. H. C.

2015-12-01

Aqueous Fe(II) produced by dissimilatory iron reduction comprises only a small fraction of total biogenic Fe(II) within an aquifer. Most biogenic Fe(II) is bound to sediments on ion exchange sites; as surface complexes and, possibly, surface precipitates; or incorporated into solid phases (e.g., siderite, magnetite). Different chemical forms of sediment-bound Fe(II) have different reactivities (e.g., with dissolved oxygen) and their formation or destruction by sorption/desorption and precipitation/dissolution is coupled to different solutes (e.g., major cations, H+, carbonate). We are quantifying chemical forms of sediment-bound Fe(II) using previously published extractions, novel extractions, and experimental studies (e.g., Fe isotopic exchange). Sediments are from Bemidji, Minnesota, where biodegradation of hydrocarbons from a burst oil pipeline has driven extensive dissimilatory Fe(III) reduction, and sites potentially impacted by unconventional oil and gas development. Generally, minimal Fe(II) was mobilized from ion exchange sites (batch desorption with MgCl2 and repeated desorption with NH4Cl). A < 2mm sediment fraction from the iron-reducing zone at Bemidji had 1.8umol/g Fe(II) as surface complexes or carbonate phases (sodium acetate at pH 5) of which ca. 13% was present as surface complexes (FerroZine extractions). Total bioavailable Fe(III) and biogenic Fe(II) (HCl extractions) was 40-50 umole/g on both background and iron-reducing zone sediments . Approximately half of the HCl-extractable Fe from Fe-reducing zone sediments was Fe(II) whereas 12 - 15% of Fe extracted from background sediments was present as Fe(II). One-third to one-half of the total biogenic Fe(II) extracted from sediments collected from a Montana prairie pothole located downgradient from a produced-water disposal pit was present as surface-complexed Fe(II).

Progress report on the effects of highway construction on suspended-sediment discharge in the Coal River and Trace Fork, West Virginia, 1975-81

USGS Publications Warehouse

Downs, S.C.; Appel, David H.

1986-01-01

Construction of the four-lane Appalachian Corridon G highway disturbed about 2 sq mi in the Coal River and 0.35 sq mi of the 4.75 sq mi Trace Fork basin in southern West Virginia. Construction had a negligible effect on runoff and suspended-sediment load in the Coal River and its major tributaries, the Little Coal and Big Coal Rivers. Drainage areas of the mainstem sites in the Coal River basin ranged from 269 to 862 sq mi, and average annual suspended-sediment yields ranged from 535 to 614 tons/sq mi for the 1975-81 water years. Suspended-sediment load in the smaller Trace Fork basin (4.72 sq mi) was significantly affected by the highway construction. Based on data from undisturbed areas upstream from construction, the normal background load at Trace Fork downstream from construction during the period July 1980 to September 1981 was estimated to be 830 tons; the measured load was 2,385 tons. Runoff from the 0.35 sq mi area disturbed by highway construction transported approximately 1,550 tons of sediment. Suspended-sediment loads from the construction zone were also higher than normal background loads during storms. (USGS)

Calibration and Sediment Load Algorithms for an Acoustic Sediment Flux Probe

DTIC Science & Technology

1994-06-01

Office of Management and Budget, Paperwork Reduction Project (0704-0118) Washington DC 20503. 1 . AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT... 1 IL BACKGROUND THEORY...BACKSCATITER TESTS ........................ 32 1 . EVaimental Tank and Tst V smd ..................................................... 32 2. Sdiment Collection

Regional distribution of mercury in sediments of the main rivers of French Guiana (Amazonian basin).

PubMed

Laperche, Valérie; Hellal, Jennifer; Maury-Brachet, Régine; Joseph, Bernard; Laporte, Pierre; Breeze, Dominique; Blanchard, François

2014-01-01

Use of mercury (Hg) for gold-mining in French Guiana (up until 2006) as well as the presence of naturally high background levels in soils, has led to locally high concentrations in soils and sediments. The present study maps the levels of Hg concentrations in river sediments from five main rivers of French Guiana (Approuague River, Comté River, Mana River, Maroni River and Oyapock River) and their tributaries, covering more than 5 450 km of river with 1 211 sampling points. The maximum geological background Hg concentration, estimated from 241 non-gold-mined streams across French Guiana was 150 ng g(-1). Significant differences were measured between the five main rivers as well as between all gold-mining and pristine areas, giving representative data of the Hg increase due to past gold-mining activities. These results give a unique large scale vision of Hg contamination in river sediments of French Guiana and provide fundamental data on Hg distribution in pristine and gold-mined areas.

Pollution and ecological risk assessment of heavy metals in the soil-plant system and the sediment-water column around a former Pb/Zn-mining area in NE Morocco.

PubMed

El Azhari, Abdellah; Rhoujjati, Ali; El Hachimi, Moulay Laârabi; Ambrosi, Jean-Paul

2017-10-01

This study discussed the environmental fate and ecological hazards of heavy metals in the soil-plant system and sediment-water column around the former Pb-Zn mining Zeïda district, in Northeastern Morocco. Spatial distribution, pollution indices, and cluster analysis were applied for assessing Pb, Zn, As, Cu and Cd pollution levels and risks. The geo-accumulation index (I geo ) was determined using two different geochemical backgrounds: i) the commonly used upper crust values, ii) local geochemical background calculated with exploratory data analysis. The soils in the vicinity of the tailings, as well as the sediments downstream of the latter, displayed much higher metal concentrations, I geo, and potential ecology risk coefficient values than other sites, classifying these sites as highly contaminated and severely hazardous. The concentrations of Pb in contaminated sediment samples also exceeded the PEC limits and are expected to cause harmful effects on sediment-dwelling organisms. Based on the comparison with the toxicity limits, the most contaminated plant samples were found around the tailings piles. The metal concentrations in both raw and filtrated water samples were overall below the drinking water standards in samples upstream and downstream of the mining center, indicating that heavy metals levels in the Moulouya River surface waters were not affected by the tailings spill. Cluster analysis suggest that: i) Pb and Zn in sediments were derived from the abandoned tailings and are mainly stored and transported as particle-bound to the bedload, ii) Pb, Zn, and Cu in the soil-plant system were related to the dispersion of tailings materials while As and Cd originated primarily from natural geological background in both the soil-plant and the water-sediment systems. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluation Options for Family Resource Centers.

ERIC Educational Resources Information Center

Horsch, Karen, Ed.; Weiss, Heather B., Ed.

Family resource centers (FRC) are emerging as a promising program approach to solving urgent social problems. Evaluation plays an important role in learning how these programs work, what their impact is, and whether they should be expanded. However, FRCs pose unique challenges to evaluation. This report considers the challenges to evaluating FRCs,…

A Day at FIRST Lego League

ERIC Educational Resources Information Center

McIntyre, Nancy

2012-01-01

This article features an after-school FIRST Lego League (FLL) program at Chaminade Middle School in Chatsworth, California, USA. The after-school FLL program feeds into the high school FIRST Robotics Competition (FRC) program wherein aspiring young engineers come to the high school team with several years of FLL experience. Through the FLL…

Linking suspended sediment transport metrics with fish functional traits in the Northwestern Great Plains (Invited)

NASA Astrophysics Data System (ADS)

Schwartz, J. S.; Simon, A.; Klimetz, L.

2009-12-01

Loss of ecological integrity due to excessive suspended sediment in rivers and streams is a major cause of water quality impairment in the United States. Although 32 states have developed numeric criteria for turbidity or suspended solids, or both according to the USEPA (2006), criteria is typically written as a percent exceedance above background and what constitutes background is not well defined. Defining a background level is problematic considering suspended sediments and related turbidity levels change with flow stage and season, and limited scientific data exists on relationships between sediment exposure and biotic response. Current assessment protocols for development of sediment total maximum daily loads (TMDLs) lack a means to link temporally-variable sediment transport rates with specific losses of ecological functions as loads increase. This study, within the in Northwestern Great Plains Ecoregion, co-located 58 USGS gauging stations with existing flow and suspended sediment data, and fish data from federal and state agencies. Suspended sediment concentration (SSC) transport metrics were quantified into exceedance frequencies of a given magnitude, duration as the number of consecutive days a given concentration was equaled or exceeded, dosage as concentration x duration, and mean annual suspended sediment yields. A functional traits-based approach was used to correlate SSC transport metrics with site occurrences of 20 fish traits organized into four main groups: preferred rearing mesohabitat, trophic structure, feeding habits, and spawning behavior. Negative correlations between SSC metrics and trait occurrences were assumed to represent potential conditions for impairment, specifically identifying an ecological loss by functional trait. Potential impairment conditions were linked with presence of the following traits: habitat preferences for stream pool and river shallow waters; feeding generalists, omnivores, piscivores; and several spawning behaviors. Using these results, TMDL targets were proposed such as < 19 mg/l SSC and 1,500 mg/l-day dosage at the 95% recurrence frequency for feeding generalists and omnivores. In general, traits correlated with: 1) a broad range of SSC exceedance frequencies and flow stages, 2) exceedance frequencies near 90-95% occurring at moderate flow stages; and 3) exceedance frequencies near 0.01-10 % occurring during floods. Unstable channels were found to be greater in transported suspended sediment than stable channels over a range of concentration exceedance frequencies, and likely influence physical habitat quality. Pool-preference and gravel spawner traits were greater in stable channels than unstable channels. Overall, a functional traits-based approach utilizing concentration-duration-frequency characteristics of suspended sediment transport was successful in identifying potential “targets” for biological impairment due to excessive sediment, and will aid in developing sediment TMDLs.

Evaluation of pulmonary dysfunctions and acid–base imbalances induced by Chlamydia psittaci in a bovine model of respiratory infection

PubMed Central

2014-01-01

Background Chlamydia psittaci (Cp) is a respiratory pathogen capable of inducing acute pulmonary zoonotic disease (psittacosis) or persistent infection. To elucidate the pathogenesis of this infection, a translational large animal model was recently introduced by our group. This study aims at quantifying and differentiating pulmonary dysfunction and acid–base imbalances induced by Cp. Methods Forty-two calves were grouped in (i) animals inoculated with Cp (n = 21) and (ii) controls sham-inoculated with uninfected cell culture (n = 21). For pulmonary function testing, impulse oscillometry, capnography, and FRC (functional residual capacity) measurement were applied to spontaneously breathing animals. Variables of acid–base status were assessed in venous blood using both (i) traditional Henderson-Hasselbalch and (ii) strong ion approach. Results Both obstructive and restrictive pulmonary disorders were induced in calves experimentally inoculated with Cp. Although disorders in respiratory mechanics lasted for 8–11 days, the pattern of spontaneous breathing was mainly altered in the period of acute illness (until 4 days post inoculation, dpi). Expiration was more impaired than inspiration, resulting in elevated FRC. Ventilation was characterised by a reduction in tidal volume (−25%) combined with an increased percentage of dead space volume and a significant reduction of alveolar volume by 10%. Minute ventilation increased significantly (+50%) due to a compensatory doubling of respiratory rate. Hyperventilatory hypocapnia at 2–3 dpi resulted in slightly increased blood pH at 2 dpi. However, the acid–base equilibrium was additionally influenced by metabolic components, i.e. the systemic inflammatory response, all of which were detected with help of the strong ion theory. Decreased concentrations of albumin (2–10 dpi), a negative acute-phase marker, resulted in a decrease in the sum of non-volatile weak acids (Atot), revealing an alkalotic effect. This was counterbalanced by acidic effects of decreased strong ion difference (SID), mediated by the interplay between hypochloraemia (alkalotic effect) and hyponatraemia (acidic effect). Conclusions This bovine model was found to be suitable for studying pathophysiology of respiratory Cp infection and may help elucidating functional host-pathogen interactions in the mammalian lung. PMID:24517577

ISOTOPIC EVALUATION OF PB OCCURRENCES IN THE RIVERINE ECOSYSTEMS OF THE KANKAKEE WATERSHED, ILLINOIS-INDIANA.

EPA Science Inventory

Environmental background levels of Pb were measured in ponds, river waters, sediments, suspended sediments, rocks, and air particulates within the Kankakee watershed during the period of 1995 to 1999. Stable isotopic Pb distinguised airborne Pb and its incorporation into riverin...

An Investigation into Heavy Metal Contamination and Mobilization in the Lower Rouge River, Michigan

NASA Astrophysics Data System (ADS)

Shihadeh, M.; Forrester, J.; Napieralski, J. A.

2010-12-01

Similar to many densely populated watersheds in the Great Lakes Basin, the Rouge River in Michigan drains a heavily urbanized watershed, which, over time, has accumulated a substantial amount of contamination due to decades of manufacturing and refining industries. Statistically significant levels of heavy metals have been found in the bed sediment of the Rouge; however, little is known about the mobilization of these contaminated bed sediments. The goal of this study was to ascertain the extent to which these potentially contaminated sediments are mobilized and transported downstream. Suspended sediment samples were collected at four sites along the lower Rouge River using composite depth integrated sediment samples three times per week, resulting in a total of twenty samples from each site. Turbidity was measured simultaneously using a YSI datalogger at all sampling locations. Sediment was also extracted from floodplain soil pits and silted vegetation, as well as river bed sediment cores along stream channel cross-sections. Heavy metal concentrations (As, Cd, Cr, Cu, Fe, Pb, Hg, Ni, Se, Zn) were analyzed using ICP-MS and compared against both background characteristics for Michigan soils and EPA Hazardous Criteria Limits. As expected, a positive correlation exists between turbidity and heavy metal concentrations. Even in the sampling sites furthest upstream, heavy metal concentrations exceeded background soil characteristics, with a few also exceeding hazardous criteria limits. The heavy metal concentrations found in the Lower Rouge affirm the elevated pollution classification of the river, depict the overall influence of industrialization on stream health, and verify that contaminated sediments are being deposited in aquatic and floodplain environments during variable flow or high discharge events. Results from this study emphasize the need to remediate bed sediments in the Rouge and suggest that there may be significant bioaccumulation potential for organisms inhabiting the floodplain corridor.

Heavy metal contamination from historic mining in upland soil and estuarine sediments of Egypt Bay, Maine, USA

NASA Astrophysics Data System (ADS)

Osher, L. J.; Leclerc, L.; Wiersma, G. B.; Hess, C. T.; Guiseppe, V. E.

2006-10-01

Concentrations of Cd, Cu, Pb and Zn in sediments of Egypt Bay in Hancock County, Maine, are elevated above background levels. The source of the contamination is Cu mining that occurred in the uplands adjacent to Egypt Stream between 1877 and 1885. Egypt Stream is a tributary to Egypt Bay. Egypt Bay is part of the Taunton Bay estuary system. The Hagan Mine was one of the mines extracting metals from the sulfide deposits in Downeast Maine north of Penobscot Bay. Metal concentrations were determined using ICP-AES after sample digestion with nitric acid. Soil collected from the coarse textured mine tailings pile contained elevated concentrations of Cd, Cu, Pb and Zn, but the majority of the surface soils at the Hagan Mine site were not contaminated. Estuary sediments from the surface to 100 cm depth were collected in four locations within Egypt Bay. Below 40 cm, metal concentrations in sediments were similar to those in uncontaminated upland soils. Metal concentrations in the estuary sediments between the surface and 26 cm were above background levels. According to 210Pb dating, the sediment at 26-34 cm depth was likely to have been deposited at the time the historic mines were in operation. Concentrations of Cd, Cu, Pb, and Zn in sediment from the 32-34 cm depth interval are similar to concentrations in the upland soil sample from the mine tailings pile. Elevated Pb concentrations in sediments from the surface to 24 cm are from atmospheric Pb deposition from anthropogenic sources. Sediment in the top 10 cm of the estuary has been mixed both by the polychaete worm Nereis virens and by those harvesting the worms for sale as fish bait.

Enrichment and geochemical mobility of heavy metals in bottom sediment of the Hoedong reservoir, Korea and their source apportionment.

PubMed

Lee, Pyeong-Koo; Kang, Min-Ju; Yu, Soonyoung; Ko, Kyung-Seok; Ha, Kyoochul; Shin, Seong-Cheon; Park, Jung Han

2017-10-01

Physicochemical characteristics of bottom sediment in the Hoedong reservoir were studied to evaluate the effectiveness of the reservoir as traps for trace metals. Roadside soil, stream sediment and background soil were also studied for comparison. Sequential extractions were carried out, and lead isotopic compositions of each extraction were determined to apportion Pb sources. Besides, particle size distribution of roadside soil, and metal concentrations and Pb isotopes of each size group were determined to characterize metal contamination. In result, Zn and Cu were enriched in sediment through roadside soil. The data on metal partitioning implied that Zn posed potential hazards for water quality. Meanwhile, the noticeable reduction of the 206 Pb/ 207 Pb isotopic ratio in the acid-soluble fraction in the size group 200 μm - 2 mm of national roadside soil indicated that this size group was highly contaminated by automotive emission with precipitation of acid-soluble secondary minerals during evaporation. Based on the Pb isotopic ratios, the dry deposition of Asian dust (AD) and non-Asian dust (NAD) affected roadside soil, while the effects of AD and NAD on bottom sediment appeared to be low given the low metal concentrations in sediment. Metal concentrations and Pb isotopic compositions indicated that sediments were a mixture of background and roadside soil. Source apportionment calculations showed that the average proportion of traffic Pb in bottom and stream sediments was respectively 34 and 31% in non-residual fractions, and 26 and 28% in residual fraction. The residual fraction of sediments appeared to be as contaminated as the non-residual fractions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Distribution of trace elements in the coastal sea sediments of Maslinica Bay, Croatia

NASA Astrophysics Data System (ADS)

Mikulic, Nenad; Orescanin, Visnja; Elez, Loris; Pavicic, Ljiljana; Pezelj, Durdica; Lovrencic, Ivanka; Lulic, Stipe

2008-02-01

Spatial distributions of trace elements in the coastal sea sediments and water of Maslinica Bay (Southern Adriatic), Croatia and possible changes in marine flora and foraminifera communities due to pollution were investigated. Macro, micro and trace elements’ distributions in five granulometric fractions were determined for each sediment sample. Bulk sediment samples were also subjected to leaching tests. Elemental concentrations in sediments, sediment extracts and seawater were measured by source excited energy dispersive X-ray fluorescence (EDXRF). Concentrations of the elements Cr, Cu, Zn, and Pb in bulk sediment samples taken in the Maslinica Bay were from 2.1 to over six times enriched when compared with the background level determined for coarse grained carbonate sediments. A low degree of trace elements leaching determined for bulk sediments pointed to strong bonding of trace elements to sediment mineral phases. The analyses of marine flora pointed to higher eutrophication, which disturbs the balance between communities and natural habitats.

Sediment Transport from Urban, Urbanizing, and Rural Areas in Johnson County, Kansas, 2006-08

USGS Publications Warehouse

Lee, Casey J.

2013-01-01

1. Studies have commonly illustrated that erosion and sediment transport from construction sites is extensive, typically 10-100X that of background levels. 2. However, to our knowledge, the affects of construction and urbanization have rarely been assessed (1) since erosion and sediment controls have been required at construction sites, and (2) at watershed (5-65 mi2) scales. This is primarily because of difficulty characterizing sediment loads in small basins. Studies (such as that illustrated from Timble, 1999) illustrated how large changes in surface erosion may not result in substantive changes in downstream sediment loads (b/c of sediment deposition on land-surfaces, floodplains, and in stream channels). 3. Improved technology (in-situ turbidity) sensors provide a good application b/c they provide an independent surrogate of sediment concentration that is more accurate at estimating sediment concentrations and loads that instantaneous streamflow.

Chemical characteristics of urban stormwater sediments and implications for environmental management, Maricopa County, Arizona

USGS Publications Warehouse

Parker, J.T.C.; Fossum, K.D.; Ingersoll, T.L.

2000-01-01

Investigations of the chemical characteristics of urban stormwater sediments in the rapidly growing Phoenix metropolitan area of Maricopa County, Arizona, showed that the inorganic component of these sediments generally reflects geologic background values. Some concentrations of metals were above background values, especially cadmium, copper, lead, and zinc, indicating an anthropogenic contribution of these elements to the sediment chemistry. Concentrations, however, were not at levels that would require soil remediation according to guidelines of the U.S. Environmental Protection Agency. Arsenic concentrations generally were above recommended values for remediation at a few sites, but these concentrations seem to reflect geologic rather than anthropogenic factors. Several organochlorine compounds no longer in use were ubiquitous in the Phoenix area, although concentrations generally were low. Chlordane, DDT and its decay products DDE and DDD, dieldrin, toxaphene, and PCBs were found at almost all sites sampled, although some of the pesticides in which these compounds are found have been banned for almost 30 years. A few sites showed exceptionally high concentrations of organochlorine compounds. On the basis of published guidelines, urban stormwater sediments do not appear to constitute a major regional environmental problem with respect to the chemical characteristics investigated here. At individual sites, high concentrations of organic compounds - chlordane, dieldrin, PCBs, and toxaphene - may require some attention. The possible environmental hazard presented by low-level organochlorine contamination is not addressed in this paper; however, high levels of toxicity in urban sediments are difficult to explain. Sediment toxicity varied significantly with time, which indicates that these tests should be evaluated carefully before they are used for management decisions.Investigations of the chemical characteristics of urban stormwater sediments in the rapidly growing Phoenix metropolitan area of Maricopa County, Arizona, showed that the inorganic component of these sediments generally reflects geologic background values. Some concentrations of metals were above background values, especially cadmium, copper, lead, and zinc, indicating an anthropogenic contribution of these elements to the sediment chemistry. Concentrations, however, were not at levels that would require soil remediation according to guidelines of the U.S. Environmental Protection Agency. Arsenic concentrations generally were above recommended values for remediation at a few sites, but these concentrations seem to reflect geologic rather than anthropogenic factors. Several organochlorine compounds no longer in use were ubiquitous in the Phoenix area, although concentrations generally were low. Chlordane, DDT and its decay products DDE and DDD, dieldrin, toxaphene, and PCBs were found at almost all sites sampled, although some of the pesticides in which these compounds are found have been banned for almost 30 years. A few sites showed exceptionally high concentrations of organochlorine compounds. On the basis of published guidelines, urban stormwater sediments do not appear to constitute a major regional environmental problem with respect to the chemical characteristics investigated here. At individual sites, high concentrations of organic compounds - chlordane, dieldrin, PCBs, and toxaphene - may require some attention. The possible environmental hazard presented by low-level organochlorine contamination is not addressed in this paper; however, high levels of toxicity in urban sediments are difficult to explain. Sediment toxicity varied significantly with time, which indicates that these tests should be evaluated carefully before they are used for management decisions.

A Method for Simulating Sedimentation of Fish Eggs to Generate Biological Effects Data for Assessing Dredging Impacts

DTIC Science & Technology

2017-03-01

activities, as well as other causes of sedimentation (e.g., agricultural practices, storm events, tidal flows). BACKGROUND AND PROBLEM: Many naturally...effects originating from many sources (e.g., agriculture , storm event, tidal flows) on multiple aquatic species and life stages. Multiple experimental

Weight-of-evidence environmental risk assessment of dumped chemical weapons after WWII along the Nord-Stream gas pipeline in the Bornholm Deep.

PubMed

Sanderson, Hans; Fauser, Patrik; Thomsen, Marianne; Larsen, Jørn Bo

2012-05-15

In connection with installation of two natural gas pipelines through the Baltic Sea between Russia and Germany, there has been concern regarding potential re-suspension of historically dumped chemical warfare agents (CWA) in a nearby dump site and the potential environmental risks associated. 192 sediment and 11 porewater samples were analyzed for CWA residues, both parent and metabolites in 2008 and 2010 along the pipeline corridor next to the dump site. Macrozoobenthos and background variables were also collected and compared to the observed CWA levels and predicted potential risks. Detection frequencies and levels of intact CWA found were low, whereas CWA metabolites were more frequently found. Re-suspension of CWA residue-containing sediment from installation of the pipelines contributes marginally to the overall background CWA residue exposure and risk along the pipeline route. The multivariate weight-of-evidence analysis showed that physical and background parameters of the sediment were of higher importance for the biota than observed CWA levels. Copyright © 2012 Elsevier B.V. All rights reserved.

FRC Compression Heating Experiment (FRCHX) at AFRL

DTIC Science & Technology

2007-06-01

Air Force Research Laboratory ( AFRL ) and Los Alamos National Laboratory (LANL) have been... Air Force Research Laboratory , Directed Energy Directorate, 3550 Aberdeen Avenue SE Kirtland AFB, NM 87117-5776 USA 8. PERFORMING ORGANIZATION REPORT...Matt Domonkos, Don Gale, Bernard Martinez, Jerry Parker, Dale Ralph, Ed Ruden, and Wayne Sommars Air Force Research Laboratory , Directed

Dendritic cells control fibroblastic reticular network tension and lymph node expansion.

PubMed

Acton, Sophie E; Farrugia, Aaron J; Astarita, Jillian L; Mourão-Sá, Diego; Jenkins, Robert P; Nye, Emma; Hooper, Steven; van Blijswijk, Janneke; Rogers, Neil C; Snelgrove, Kathryn J; Rosewell, Ian; Moita, Luis F; Stamp, Gordon; Turley, Shannon J; Sahai, Erik; Reis e Sousa, Caetano

2014-10-23

After immunogenic challenge, infiltrating and dividing lymphocytes markedly increase lymph node cellularity, leading to organ expansion. Here we report that the physical elasticity of lymph nodes is maintained in part by podoplanin (PDPN) signalling in stromal fibroblastic reticular cells (FRCs) and its modulation by CLEC-2 expressed on dendritic cells. We show in mouse cells that PDPN induces actomyosin contractility in FRCs via activation of RhoA/C and downstream Rho-associated protein kinase (ROCK). Engagement by CLEC-2 causes PDPN clustering and rapidly uncouples PDPN from RhoA/C activation, relaxing the actomyosin cytoskeleton and permitting FRC stretching. Notably, administration of CLEC-2 protein to immunized mice augments lymph node expansion. In contrast, lymph node expansion is significantly constrained in mice selectively lacking CLEC-2 expression in dendritic cells. Thus, the same dendritic cells that initiate immunity by presenting antigens to T lymphocytes also initiate remodelling of lymph nodes by delivering CLEC-2 to FRCs. CLEC-2 modulation of PDPN signalling permits FRC network stretching and allows for the rapid lymph node expansion--driven by lymphocyte influx and proliferation--that is the critical hallmark of adaptive immunity.

Dendritic Cells Control Fibroblastic Reticular Network Tension and Lymph Node Expansion

PubMed Central

Acton, Sophie E.; Farrugia, Aaron J.; Astarita, Jillian L.; Mourão-Sá, Diego; Jenkins, Robert P.; Nye, Emma; Hooper, Steven; van Blijswijk, Janneke; Rogers, Neil C.; Snelgrove, Kathryn J.; Rosewell, Ian; Moita, Luis F.; Stamp, Gordon; Turley, Shannon J.; Sahai, Erik; Sousa, Caetano Reis e

2014-01-01

Following immunogenic challenge, infiltrating and dividing lymphocytes significantly increase lymph node (LN) cellularity leading to organ expansion1,2. Here we report that the physical elasticity of LNs is maintained in part by podoplanin (PDPN) signalling in stromal fibroblastic reticular cells (FRCs) and its modulation by CLEC-2 expressed on dendritic cells (DCs). We show that PDPN induces actomyosin contractility in FRCs via activation of RhoA/C and downstream Rho-kinase. Engagement by CLEC-2 causes PDPN clustering and rapidly uncouples PDPN from RhoA/C activation, relaxing the actomyosin cytoskeleton and permitting FRC stretching. Notably, administration of CLEC-2 protein to immunised mice augments LN expansion. In contrast, the latter is significantly constrained in mice selectively lacking CLEC-2 expression in DCs. Thus, the same DCs that initiate immunity by presenting antigens to T lymphocytes3 also initiate remodeling of LNs by delivering CLEC-2 to FRCs. CLEC-2 modulation of PDPN signalling permits FRC network stretching and allows for the rapid LN expansion driven by lymphocyte influx and proliferation that is the critical hallmark of adaptive immunity. PMID:25341788

A direct fusion drive for rocket propulsion

NASA Astrophysics Data System (ADS)

Razin, Yosef S.; Pajer, Gary; Breton, Mary; Ham, Eric; Mueller, Joseph; Paluszek, Michael; Glasser, Alan H.; Cohen, Samuel A.

2014-12-01

The Direct Fusion Drive (DFD), a compact, anuetronic fusion engine, will enable more challenging exploration missions in the solar system. The engine proposed here uses a deuterium-helium-3 reaction to produce fusion energy by employing a novel field-reversed configuration (FRC) for magnetic confinement. The FRC has a simple linear solenoid coil geometry yet generates higher plasma pressure, hence higher fusion power density, for a given magnetic field strength than other magnetic-confinement plasma devices. Waste heat generated from the plasma's Bremsstrahlung and synchrotron radiation is recycled to maintain the fusion temperature. The charged reaction products, augmented by additional propellant, are exhausted through a magnetic nozzle. A 1 MW DFD is presented in the context of a mission to deploy the James Webb Space Telescope (6200 kg) from GPS orbit to a Sun-Earth L2 halo orbit in 37 days using just 353 kg of propellant and about half a kilogram of 3He. The engine is designed to produce 40 N of thrust with an exhaust velocity of 56.5 km/s and has a specific power of 0.18 kW/kg.

First results of transcritical magnetized collisionless shock studies on MSX

NASA Astrophysics Data System (ADS)

Weber, T. E.; Smith, R. J.; Hutchinson, T. M.; Taylor, S. F.; Hsu, S. C.

2014-10-01

Magnetized collisionless shocks exhibit transitional length and time scales much shorter than can be created through collisional processes. They are common throughout the cosmos, but have historically proven difficult to create in the laboratory. The Magnetized Shock Experiment (MSX) at LANL produces super-Alfvénic shocks through the acceleration and subsequent stagnation of Field Reversed Configuration (FRC) plasmoids against a strong magnetic mirror and flux-conserving vacuum boundary. Plasma flows have been produced with sonic and Alfvén Mach numbers up to ~10 over a wide range of plasma beta with embedded perpendicular, oblique, and parallel magnetic field. Macroscopic ion skin-depth and long ion-gyroperiod enable diagnostic access to relevant shock physics using common methods. Variable plasmoid velocity, density, temperature, and magnetic field provide access to a wide range of shock conditions, and a campaign to study the physics of transcritical and supercritical shocks within the FRC plasmoid is currently underway. An overview of the experimental design, diagnostics suite, physics objectives, and recent results will be presented. Supported by DOE Office of Fusion Energy Sciences under DOE Contract DE-AC52-06NA25369.

Hybrid reconstruction of field-reversed configurations

NASA Astrophysics Data System (ADS)

Steinhauer, Loren; TAE Team

2016-10-01

Field-reversed configurations (FRC) are poorly represented by fluid-based models and require instead an ion-distribution function. Two such populations are needed since ``core'' ions are roughly restricted to the region inside the separatrix, whereas ``periphery'' ions can escape along open field lines. The Vlasov equation governs the distribution, the general solution to which is an arbitrary function of the constants of motion (Hamiltonian, canonical angular momentum). Only a small subset of such distributions are realistic in view of collisions, which smooth the distribution, and instabilities, which reorganize the field structure. Collisions and end loss are included if the distribution is a solution to the Fokker-Planck (FP) equation. Vlasov and FP solutions are nearly identical in weakly-collisional plasmas. Numerical construction of such equilibria requires solving both Ampere's law for the magnetic flux variable and the ponderous task of a full velocity-space integration at each point. The latter can be done analytically by expressing the distribution as the superposition of simple basis elements. This procedure allows rapid reconstruction of evolving equilibria based on limited diagnostic observables in FRC experiments.

Fibre reinforced concrete exposed to elevated temperature

NASA Astrophysics Data System (ADS)

Novák, J.; Kohoutková, A.

2017-09-01

Although concrete when subject to fire performs very well, its behaviour and properties change dramatically under high temperature due to damaged microstructure and mesostructure. As fibre reinforced concrete (FRC) represents a complex material composed of various components with different response to high temperature, to determine its behaviour and mechanical properties in fire is a demanding task. The presented paper provides a summary of findings on the fire response of fibre FRC. Namely, the information on steel fibre reinforced concrete (SFRC), synthetic fibre reinforced concrete and hybrid (steel + synthetic) fibre reinforced concrete have been gathered from various contributions published up to date. The mechanical properties including the melting point and ignition point of fibres affect significantly the properties of concrete composites with addition of fibres. The combination of steel and synthetic fibres represents a promising alternative how to ensure good toughness of a concrete composite before heating and improve its residual mechanical behaviour and spalling resistance as well as the ductility after heating. While synthetic fibres increase concrete spalling resistance, steel fibres in a concrete mix leads to an improvement in both mechanical properties and resistance to heating effects.

Infant lung function tests as endpoints in the ISIS multicenter clinical trial in cystic fibrosis.

PubMed

Davis, Stephanie D; Ratjen, Felix; Brumback, Lyndia C; Johnson, Robin C; Filbrun, Amy G; Kerby, Gwendolyn S; Panitch, Howard B; Donaldson, Scott H; Rosenfeld, Margaret

2016-05-01

The Infant Study of Inhaled Saline (ISIS) in CF was the first multicenter clinical trial to utilize infant pulmonary function tests (iPFTs) as an endpoint. Secondary analysis of ISIS data was conducted in order to assess feasibility of iPFT measures and their associations with respiratory symptoms. Standard deviations were calculated to aid in power calculations for future clinical trials. Seventy-three participants enrolled, 70 returned for the final visit; 62 (89%) and 45 (64%) had acceptable paired functional residual capacity (FRC) and raised volume measurements, respectively. Mean baseline FEV0.5, FEF75 and FRC z-scores were 0.3 (SD: 1.2), -0.2 (SD: 2.0), and 1.8 (SD: 2.0). iPFTs are not appropriate primary endpoints for multicenter clinical trials due to challenges of obtaining acceptable data and near-normal average raised volume measurements. Raised volume measures have potential to serve as secondary endpoints in future clinical CF trials. Copyright © 2015 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Degradation of crude 4-MCHM (4-methylcyclohexanemethanol) in sediments from Elk River, West Virginia

USGS Publications Warehouse

Cozzarelli, Isabelle M.; Akob, Denise M.; Baedecker, Mary; Spencer, Tracey; Jaeschke, Jeanne B.; Dunlap, Darren S.; Mumford, Adam C.; Poret-Peterson, Amisha T.; Chambers, Douglas B.

2017-01-01

In January 2014, approximately 37 800 L of crude 4-methylcyclohexanemethanol (crude MCHM) spilled into the Elk River, West Virginia. To understand the long-term fate of 4-MCHM, we conducted experiments under environmentally relevant conditions to assess the potential for the 2 primary compounds in crude MCHM (1) to undergo biodegradation and (2) for sediments to serve as a long-term source of 4-MCHM. We developed a solid phase microextraction (SPME) method to quantify the cis- and trans-isomers of 4-MCHM. Autoclaved Elk River sediment slurries sorbed 17.5% of cis-4-MCHM and 31% of trans-4-MCHM from water during the 2-week experiment. Sterilized, impacted, spill-site sediment released minor amounts of cis- and up to 35 μg/L of trans-4-MCHM into water, indicating 4-MCHM was present in sediment collected 10 months post spill. In anoxic microcosms, 300 μg/L cis- and 150 μg/L trans-4-MCHM degraded to nondetectable levels in 8–13 days in both impacted and background sediments. Under aerobic conditions, 4-MCHM isomers degraded to nondetectable levels within 4 days. Microbial communities at impacted sites differed in composition compared to background samples, but communities from both sites shifted in response to crude MCHM amendments. Our results indicate that 4-MCHM is readily biodegradable under environmentally relevant conditions.

Overweight, Obesity, and Lung Function in Children and Adults-A Meta-analysis.

PubMed

Forno, Erick; Han, Yueh-Ying; Mullen, James; Celedón, Juan C

There is conflicting evidence on the effect of obesity on lung function in adults and children with and without asthma. We aimed to evaluate the relation between overweight or obesity and lung function, and whether such relationship varies by age, sex, or asthma status. We searched PubMed, Scopus, CINAHL, Cochrane, and EMBASE for all studies (in English) reporting on obesity status (by body mass index) and lung function, from 2005 to 2017. Main outcomes were forced expiratory volume in 1 second (FEV 1 ), forced vital capacity (FVC), FEV 1 /FVC, forced expiratory flow between 25th and 75th percentile of the forced vital capacity (FEF 25-75 ), total lung capacity (TLC), residual volume (RV), and functional residual capacity (FRC). Random-effects models were used to calculate the pooled risk estimates; each study was weighed by the inverse effect size variance. For each outcome, we compared overweight or obese ("obese") subjects with those of normal weight. All measures of lung function were decreased among obese subjects. Obese adults showed a pattern (lower FEV 1 , FVC, TLC, and RV) different from obese children (more pronounced FEV 1 /FVC deficit with unchanged FEV 1 or FVC). There were also seemingly different patterns by asthma status, in that subjects without asthma had more marked decreases in FEV 1 , TLC, RV, and FRC than subjects with asthma. Subjects who were obese (as compared with overweight) had even further decreased FEV 1 , FVC, TLC, RV, and FRC. Obesity is detrimental to lung function, but specific patterns differ between children and adults. Physicians should be aware of adverse effects of obesity on lung function, and weight control should be considered in the management of airway disease among the obese. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

ECN-1606

NASA Image and Video Library

1967-01-11

In this 1967 NASA Flight Reserch Center photograph the Lunar Landing Research Vehicle (LLRV) is viewed from the front. This photograph provideds a good view of the pilot’s platform with the restrictive cockpit view like that of he real Lunar Module (LM) When Apollo planning was underway in 1960, NASA was looking for a simulator to profile the descent to the Moon's surface. Three concepts surfaced: an electronic simulator, a tethered device, and the ambitious Dryden contribution, a free-flying vehicle. All three became serious projects, but eventually the NASA Flight Research Center’s (FRC) Lunar Landing Research Vehicle (LLRV) became the most significant one. After conceptual planning and meetings with engineers from Bell Aerosystems Company, Buffalo, N.Y., NASA FRC issued a $3.6 million production contract awarded in 1963, for delivery of the first of two vehicles for flight studies. Built of tubular aluminum alloy like a giant four-legged bedstead, the vehicle was to simulate a lunar landing profile from around 1500 feet to the Moon’s surface. The LLRV had a turbofan engine mounted vertically in a gimbal, with 4200 pounds of thrust. The engine, lifted the vehicle up to the test altitude and was then throttled back to support five-sixths of the vehicle's weight, thus simulating the reduced gravity of the Moon. Two lift rockets with thrust that could be varied from 100 to 500 pounds handled the LLRV's rate of descent and horizontal translations. Sixteen smaller rockets, mounted in pairs, gave the pilot control in pitch, yaw, and roll.. The pilot’s platform extended forward between two legs while an electronics platform, similarly located, extended rearward. The pilot had a zero-zero ejection seat that would then lift him away to safety. The two LLRVs were shipped from Bell to the FRC in April 1964, with program emphasis on vehicle No. 1. The first flight, Oct. 30, 1964, NASA research pilot Joe Walker flew it three times for a total of just under 60 seconds

Acute and population level toxicity of imidacloprid and fenpyroximate on an important egg parasitoid, Trichogramma cacoeciae (Hymenoptera: Trichogrammatidae).

PubMed

Saber, Moosa

2011-08-01

One focus of integrated pest management (IPM) is the use of biological and chemical control in an optimal way. The availability of selective pesticides is important as is information about both lethal and sublethal effects of pesticides on biocontrol agents. Acute and sublethal effects of imidacloprid and fenpyroximate exposure were studied on adult stage of egg parasitoid Trichogramma cacoeciae Marchal and the emergence rate and life table parameters were determined. The adult wasps were exposed to field recommended concentration (FRC) of the pesticides on glass plates. Field rates of imidacloprid and fenpyroximate caused 100 and 32% adult mortality, respectively. Based on concentration-response experiments, the LC(50) values of imidacloprid and fenpyroximate were 6.25 and 1,949 ppm, respectively. The effect of imidacloprid and fenpyroximate on larvae, prepupae and pupae of the parasitoid was tested by exposing parasitized eggs of Sitotroga cerealella Olivier or Cydia pomonella L. to the FRC. Imidacloprid and fenpyroximate reduced adult emergence by 10.7 and 29%, respectively, when S. cerealella eggs were used as the host and 10.9 and 24.9%, respectively, when C. pomonella eggs were used as the host. Population parameters of emerged adults from treated pre-imaginal stages by FRC of the pesticides were also studied. The parameters were longevity and progeny production of emergent adults and also intrinsic rate of increase (r ( m )), generation time (T) and doubling time (DT). Longevity and progeny production of the emergent adults was not affected by pesticide exposure in comparison to the control. In addition, none of population parameters such as r ( m ), T and DT were affected by pesticide exposure. The intrinsic rate of increase for the control, fenpyroximate and imidacloprid exposed populations were 0.388, 0.374, and 0.372 female offspring per female per day, respectively. Overall, results of this study suggest a relative compatibility between fenpyroximate and T. cacoeciae, but imidacloprid showed deleterious effects on adults of the parasitoid.

Multivariate analysis and geochemical approach for assessment of metal pollution state in sediment cores.

PubMed

Jamshidi-Zanjani, Ahmad; Saeedi, Mohsen

2017-07-01

Vertical distribution of metals (Cu, Zn, Cr, Fe, Mn, Pb, Ni, Cd, and Li) in four sediment core samples (C 1 , C 2 , C 3 , and C 4 ) from Anzali international wetland located southwest of the Caspian Sea was examined. Background concentration of each metal was calculated according to different statistical approaches. The results of multivariate statistical analysis showed that Fe and Mn might have significant role in the fate of Ni and Zn in sediment core samples. Different sediment quality indexes were utilized to assess metal pollution in sediment cores. Moreover, a new sediment quality index named aggregative toxicity index (ATI) based on sediment quality guidelines (SQGs) was developed to assess the degree of metal toxicity in an aggregative manner. The increasing pattern of metal pollution and their toxicity degree in upper layers of core samples indicated increasing effects of anthropogenic sources in the study area.

Near bed suspended sediment flux by single turbulent events

NASA Astrophysics Data System (ADS)

Amirshahi, Seyed Mohammad; Kwoll, Eva; Winter, Christian

2018-01-01

The role of small scale single turbulent events in the vertical mixing of near bed suspended sediments was explored in a shallow shelf sea environment. High frequency velocity and suspended sediment concentration (SSC; calibrated from the backscatter intensity) were collected using an Acoustic Doppler Velocimeter (ADV). Using quadrant analysis, the despiked velocity time series was divided into turbulent events and small background fluctuations. Reynolds stress and Turbulent Kinetic Energy (TKE) calculated from all velocity samples, were compared to the same turbulent statistics calculated only from velocity samples classified as turbulent events (Reevents and TKEevents). The comparison showed that Reevents and TKEevents was increased 3 and 1.6 times, respectively, when small background fluctuations were removed and that the correlation with SSC for TKE could be improved through removal of the latter. The correlation between instantaneous vertical turbulent flux (w ‧) and SSC fluctuations (SSC ‧) exhibits a tidal pattern with the maximum correlation at peak ebb and flood currents, when strong turbulent events appear. Individual turbulent events were characterized by type, strength, duration and length. Cumulative vertical turbulent sediment fluxes and average SSC associated with individual turbulent events were calculated. Over the tidal cycle, ejections and sweeps were the most dominant events, transporting 50% and 36% of the cumulative vertical turbulent event sediment flux, respectively. Although the contribution of outward interactions to the vertical turbulent event sediment flux was low (11%), single outward interaction events were capable of inducing similar SSC ‧ as sweep events. The results suggest that on time scales of tens of minutes to hours, TKE may be appropriate to quantify turbulence in sediment transport studies, but that event characteristics, particular the upward turbulent flux need to be accounted for when considering sediment transport on process time scales.

Lead in Lake Michigan and Green Bay Surficial Sediments

EPA Science Inventory

Sediment cores were collected in 1987-1989 in Green Bay using a box corer and in 1994-1996 in Lake Michigan using a box corer and a PONAR. Core samples were segmented and dated. Historic background lead concentrations were determined for Green Bay (range=1.8-39.3 mg/kg, mean=14...

Geochemical studies of Fe, Mn, Co, As, Cr, Sb, Zn, Sc and V in surface sediments from Jiaozhou Bay

NASA Astrophysics Data System (ADS)

Wu, Run; Li, Pei-Quan; Miao, Lu-Tian; Zhang, Shu-Xin; Tian, Wei-Zhi

1994-12-01

The contents of nearly forty-elements in surface sediments in Jiaozhou Bay were determined using a Neutron Activation Analysis Technique (Grancini, et al., 1976; Li Peiquan et al., 1985, 1986; Li Xiuxia et al., 1986). This paper's detailed discussion on only nine elements (Fe, Mn, Co, Cr, Sc, As, Sb, Zn and V) includes their distributions, concentrations, correlationships, material sources, background, etc. Based on Zavaristski's classification method, Fe, Mn, Co, Cr and V belong to the second group; As and Sb to the eighth groups: Sc and Zn to the third and sixth groups. It was found that their notably good correlationship is mainly due to the similarity of their ionic structures and that their variation is controlled by the Fe content (except Mn). The source of sediments is mainly terristrial material, and the composition of sediment is similar to that of shale and shale+clay. The contents for a large number of elements are within the scope of the background level, but there still is pollution of Zn and Cr, at least in a few stations.

M2-F2 flight preparation and launch

NASA Technical Reports Server (NTRS)

1969-01-01

This movie clip runs about 27 seconds and shows the cockpit canopy close-out by the ground crew, the aircraft hanging from the NB-52B wing pylon, and the M2-F2 being dropped away from the mothership. A fleet of lifting bodies flown at the NASA Flight Research Center (FRC), Edwards, California, from 1963 to l975 demonstrated the ability of pilots to maneuver (in the atmosphere) and safely land a wingless vehicle. These lifting bodies were basically designed so they could fly back to Earth from space and be landed like an aircraft at a pre-determined site. They served as precursors of today's Space Shuttle, the X-33, and the X-38, providing technical and operational engineering data that shaped all three space vehicles. (In 1976 NASA renamed the FRC as the NASA Dryden Flight Research Center (DFRC) in honor of Hugh L. Dryden.) In 1962, FRC Director Paul Bikle approved a program to build a lightweight, unpowered lifting body as a prototype to flight test the wingless concept. It would look like a 'flying bathtub,' and was designated the M2-F1. Built by Gus Briegleb, a sailplane builder from El Mirage, California, it featured a plywood shell, placed over a tubular steel frame crafted at the FRC. Construction was completed in 1963. The success of Dryden's M2-F1 program led to NASA's development and construction of two heavyweight lifting bodies based on studies at NASA Ames Research Center and NASA and Langley Research Center -- the M2-F2 and the HL-10, both built by the Northrop Corporation, Los Angeles, California. The 'M' refers to 'manned' and 'F' refers to 'flight' version. 'HL' comes from 'horizontal landing' and '10' is for the tenth lifting body model to be investigated by Langley. The first flight of the M2-F2 -- which looked much like the M2-F1 -- occurred on July 12, 1966. Thompson was the pilot. By then, the same B-52 used to air launch the famed X-15 rocket research aircraft had been modified to also carry the lifting bodies into the air and Thompson was dropped from the B-52 wing pylon mount at an altitude of 45,000 feet on that maiden glide flight. On May 10, 1967, during the sixteenth glide flight leading up to powered flight, a landing accident severely damaged the vehicle and seriously injured the NASA pilot, Bruce Peterson. Following the mishap, the M2-F2 was redesigned with a center fin as the M2-F3, which flew from 1970 to 1972. The M2-F2 weighed 4,620 pounds without ballast, was roughly 22 feet long, and had a width of about 10 feet.

Long-term monitoring of metal pollution in sediments from the estuary of the Nerbioi-Ibaizabal River (2005-2010)

NASA Astrophysics Data System (ADS)

Gredilla, Ainara; Fdez-Ortiz de Vallejuelo, Silvia; Arana, Gorka; de Diego, Alberto; Madariaga, Juan Manuel

2013-10-01

This work aims to investigate the spatial and temporal distribution of trace metals in sediment samples taken from the Nerbioi-Ibaizabal River estuary (Bilbao, Basque Country) over the course of a long-term surveillance monitoring programme from 2005 to 2010. Sediment Quality Guidelines (SQGs) and the geoaccumulation indexes (Igeo) were used to assess the environmental risk posed by metal content in the estuary sediment. Sediment was collected at eight different sites in the estuary every three months over the period of investigation. A total of 14 elements (Al, As, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sn, V and Zn) were selected and the concentration of each was measured in all samples. Additionally, conductivity, pH and the concentration of carbonate, total organic carbon and fulvic and humic acids were also measured in those samples collected in sampling campaigns from March 2006 to October 2008. The concentration of most of the metals systematically decreased over the period of investigation. There are still some points of the estuary (those located in the surroundings of the Gobela and Galindo tributaries), however, where concentrations of As, Cd, Cu, Pb and Zn are significantly higher than the background values estimated for the area. According to the mean Effects Range Median quotients (mERMqs) calculated for these sites, sediments may still pose a toxicological threat to living organisms. Metal content in inner estuary sediment is low. Specific point sources of metals to the estuary, together with background contamination of diffuse origin, are probably responsible for this situation.

Baseline trace metals in water and sediment of the Baleh River-a tropical river in Sarawak, Malaysia.

PubMed

Sim, Siong Fong; Chai, Hui Ping; Nyanti, Lee; Ling, Teck Yee; Grinang, Jongkar

2016-09-01

Quantitative indices are classically employed to evaluate the contamination status of metals with reference to the baseline concentrations. The baselines vary considerably across different geographical zones. It is imperative to determine the local geochemical baseline to evaluate the contamination status. No study has been done to establish the background concentrations in tropical rivers of this region. This paper reports the background concentrations of metals in water and sediment of the Baleh River, Sarawak, derived based on the statistical methods where the areas possibly disturbed are distinguished from the undisturbed area. The baseline levels of six elements in water determined were Al (0.34 mg/L), Fe (0.51 mg/L), Mn (0.12 mg/L), Cu (0.01 mg/L), Pb (0.03 mg/L), and Zn (0.05 mg/L). Arsenic and selenium were below the detection limit. For sediment, the background values were established according to statistical methods including (mean + 2σ), iterative 2σ, cumulative distribution frequency, interquartile, and calculation distribution function. The background values derived using the iterative 2σ algorithm and calculated distribution function were relatively lower. The baseline levels calculated were within the range reported in the literatures mainly from tropical and sub-tropical regions. The upper limits proposed for nine elements in sediment were Al (100,879 mg/kg), Cr (75.45 mg/kg), Cu (34.59 mg/kg), Fe (37,823 mg/kg), Mn (793 mg/kg), Ni (22.88 mg/kg), Pb (27.26 mg/kg), Zn (70.64 mg/kg), and Hg (0.33 mg/kg). Quantitative indices calculated suggest low risk of contamination at the Baleh River.

Hydrothermal activity lowers trophic diversity in Antarctic hydrothermal sediments

NASA Astrophysics Data System (ADS)

Bell, James B.; Reid, William D. K.; Pearce, David A.; Glover, Adrian G.; Sweeting, Christopher J.; Newton, Jason; Woulds, Clare

2017-12-01

Hydrothermal sediments are those in which hydrothermal fluid is discharged through sediments and are one of the least studied deep-sea ecosystems. We present a combination of microbial and biochemical data to assess trophodynamics between and within hydrothermal and background areas of the Bransfield Strait (1050-1647 m of depth). Microbial composition, biomass, and fatty acid signatures varied widely between and within hydrothermally active and background sites, providing evidence of diverse metabolic activity. Several species had different feeding strategies and trophic positions between hydrothermally active and inactive areas, and the stable isotope values of consumers were not consistent with feeding morphology. Niche area and the diversity of microbial fatty acids was lowest at the most hydrothermally active site, reflecting trends in species diversity. Faunal uptake of chemosynthetically produced organics was relatively limited but was detected at both hydrothermal and non-hydrothermal sites, potentially suggesting that hydrothermal activity can affect trophodynamics over a much wider area than previously thought.

Occurrence and partitioning of antibiotic compounds found in the water column and bottom sediments from a stream receiving two wastewater treatment plant effluents in northern New Jersey, 2008.

PubMed

Gibs, Jacob; Heckathorn, Heather A; Meyer, Michael T; Klapinski, Frank R; Alebus, Marzooq; Lippincott, Robert L

2013-08-01

An urban watershed in northern New Jersey was studied to determine the presence of four classes of antibiotic compounds (macrolides, fluoroquinolones, sulfonamides, and tetracyclines) and six degradates in the water column and bottom sediments upstream and downstream from the discharges of two wastewater treatment plants (WWTPs) and a drinking-water intake (DWI). Many antibiotic compounds in the four classes not removed by conventional WWTPs enter receiving waters and partition to stream sediments. Samples were collected at nine sampling locations on 2 days in September 2008. Two of the nine sampling locations were background sites upstream from two WWTP discharges on Hohokus Brook. Another background site was located upstream from a DWI on the Saddle River above the confluence with Hohokus Brook. Because there is a weir downstream of the confluence of Hohokus Brook and Saddle River, the DWI receives water from Hohokus Brook at low stream flows. Eight antibiotic compounds (azithromycin (maximum concentration 0.24 μg/L), ciprofloxacin (0.08 μg/L), enrofloxacin (0.015 μg/L), erythromycin (0.024 μg/L), ofloxacin (0.92 μg/L), sulfamethazine (0.018 μg/L), sulfamethoxazole (0.25 μg/L), and trimethoprim (0.14 μg/L)) and a degradate (erythromycin-H2O (0.84 μg/L)) were detected in the water samples from the sites downstream from the WWTP discharges. The concentrations of six of the eight detected compounds and the detected degradate compound decreased with increasing distance downstream from the WWTP discharges. Azithromycin, ciprofloxacin, ofloxacin, and trimethoprim were detected in stream-bottom sediments. The concentrations of three of the four compounds detected in sediments were highest at a sampling site located downstream from the WWTP discharges. Trimethoprim was detected in the sediments from a background site. Pseudo-partition coefficients normalized for streambed sediment organic carbon concentration were calculated for azithromycin, ciprofloxacin, and ofloxacin. Generally, there was good agreement between the decreasing order of the pseudo-partition coefficients in this study and the order reported in the literature. Published by Elsevier B.V.

Occurence of antibiotic compounds found in the water column and bottom sediments from a stream receiving two waste water treatment plant effluents in northern New Jersey, 2008

USGS Publications Warehouse

Gibs, Jacob; Heckathorn, Heather A.; Meyer, Michael T.; Klapinski, Frank R.; Alebus, Marzooq; Lippincott, Robert

2013-01-01

An urban watershed in northern New Jersey was studied to determine the presence of four classes of antibiotic compounds (macrolides, fluoroquinolones, sulfonamides, and tetracyclines) and six degradates in the water column and bottom sediments upstream and downstream from the discharges of two wastewater treatment plants (WWTPs) and a drinking-water intake (DWI). Many antibiotic compounds in the four classes not removed by conventional WWTPs enter receiving waters and partition to stream sediments. Samples were collected at nine sampling locations on 2 days in September 2008. Two of the nine sampling locations were background sites upstream from two WWTP discharges on Hohokus Brook. Another background site was located upstream from a DWI on the Saddle River above the confluence with Hohokus Brook. Because there is a weir downstream of the confluence of Hohokus Brook and Saddle River, the DWI receives water from Hohokus Brook at low stream flows. Eight antibiotic compounds (azithromycin (maximum concentration 0.24 μg/L), ciprofloxacin (0.08 μg/L), enrofloxacin (0.015 μg/L), erythromycin (0.024 μg/L), ofloxacin (0.92 μg/L), sulfamethazine (0.018 μg/L), sulfamethoxazole (0.25 μg/L), and trimethoprim (0.14 μg/L)) and a degradate (erythromycin-H2O (0.84 μg/L)) were detected in the water samples from the sites downstream from the WWTP discharges. The concentrations of six of the eight detected compounds and the detected degradate compound decreased with increasing distance downstream from the WWTP discharges. Azithromycin, ciprofloxacin, ofloxacin, and trimethoprim were detected in stream-bottom sediments. The concentrations of three of the four compounds detected in sediments were highest at a sampling site located downstream from the WWTP discharges. Trimethoprim was detected in the sediments from a background site. Pseudo-partition coefficients normalized for streambed sediment organic carbon concentration were calculated for azithromycin, ciprofloxacin, and ofloxacin. Generally, there was good agreement between the decreasing order of the pseudo-partition coefficients in this study and the order reported in the literature.

Training in Family Support: Towards a Conceptual Framework. A Report from a Wingspread Conference.

ERIC Educational Resources Information Center

Vogel, Christine

This report presents the results of a conference held by the Family Resource Coalition (FRC) in October 1991, which brought together an interdisciplinary group of academics and family resource practitioners to address questions of quality in family support and, more specifically, in staff development and personnel. The report provides the…

Modeling of neutral entrainment in an FRC thruster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brackbill, Jeremiah; Gimelshein, Natalia; Gimelshein, Sergey

2012-11-27

Neutral entrainment in a field reversed configuration thruster is modeled numerically with an implicit PIC code extended to include thermal and chemical interactions between plasma and neutral particles. The contribution of charge exchange and electron impact ionization reactions is analyzed, and the sensitivity of the entrainment efficiency to the plasmoid translation velocity and neutral density is evaluated.

An inventory of suspended sediment stations and type of data analysis for Pennsylvania streams, 1947-1970

USGS Publications Warehouse

Ott, Arthur N.; Commings, Allen B.

1972-01-01

Data concerning suspended sediment concentrations and loads, frequency of occurrence of suspended sediment concentrations, and long-term trends of annual suspended sediment loads are important tools for today's environmental manager. These data are required background for those concerned with establishing and enforcing erosion and sedimentation control regulations and sediment concentration or turbidity standards for water-quality criteria, or those concerned with designing for adequate long-term water storage in reservoirs (sediment load), for efficient municipal and industrial plant operation (sediment concentration frequency), etc.This is a compilation of the location, period of record, sampling frequency and type of data synthesis for suspended sediment carried by Pennsylvania streams. Figures 1 and 2 show the approximate locations of sediment sampling stations in Pennsylvania. All of the sediment data listed were collected by the U. S. Geological Survey mainly in cooperation with the following Federal, State, and local agencies.Pennsylvania Department of Environmental Resources     Bureau of Engineering and Construction     Soil and Water Conservation CommissionPennsylvania Department of TransportationCity of PhiladelphiaBrandywine Valley AssociationDelaware Geological SurveyConestoga Valley AssociationLehigh County Soil and Water Conservation DistrictCorps of Engineers, U. S. Army

Inter-lab testing of Hyalella azteca water and sediment methods: 1 background and overview of the 42-d survival, growth and reproduction test

EPA Science Inventory

Over the past four years, USEPA-Duluth, USGS-Columbia, the Illinois Natural History Survey, and Environment Canada have been conducting studies to refine the USEPA and ASTM International methods for conducting 10- to 42-d water or sediment toxicity exposures with the amphipod Hya...

Assessing environmental impact from gas and oil exploration in the SW Barents Sea using benthic foraminiferal assemblages

NASA Astrophysics Data System (ADS)

Dijkstra, N.; Junttila, J.; Husum, K.; Carroll, J.; Hald, M.

2012-04-01

During the last decades petroleum industry and shipping activities have increased in the SW Barents Sea. Oil exploration wells were drilled in the 1980s with production starting in 2007. These activities are projected to expand in the coming years. As part of the Northern Environmental Waste Management (EWMA) project, a competence cluster for petroleum industry related waste handling, we investigate the impacts of enhanced anthropogenic activities on benthic foraminiferal assemblages in the SW Barents Sea. Sediment cores (0-20 cm) from sites in proximity to two oil- and gas fields are under investigation. These sediment cores, dated with the 210Pb method, represent the last 90 to 150 years. Both dead and living benthic foraminifera (100 µm-1 mm) were counted to elucidate differences in foraminiferal assemblages between pre-impact and recent conditions. In addition, the heavy metal concentrations, persistent organic pollutant (POP) concentrations, grain size and total organic content (TOC) of the sediment cores have been analyzed. Pollution levels of the surface sediments (0-1 cm) are of background to good level (level I-II) according to the definitions of the Water Framework Directorate (WFD). Patterns in living benthic foraminiferal assemblages identified in the sea floor surface sediments, are the result of natural environmental changes such as depth, water mass and sediment composition. Further downcore (1-20 cm) pollution levels are in general of background environmental status (WFD level I). However, at some depth intervals, especially in sediment cores from the near proximity of the oil- and gas- fields, pollution levels are slightly enhanced (WFD level II). Further work will include statistical comparison of dead and living foraminiferal assemblages with sediment pollution levels, sediment properties, and oceanographic conditions. This research contributes to the development of foraminifera as a useful bio-monitoring technique for the Arctic region as industrial activities increase in the coming years.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Page, D.S.; Boehm, P.D.; Douglas, G.S.

Advanced hydrocarbon fingerprinting methods and improved analytical methods make possible the quantitative discrimination of the multiple sources of hydrocarbons in the benthic sediments of Prince William Sound (PWS) and the Gulf of Alaska. These methods measure an extensive range of polycyclic aromatic hydrocarbons (PAH) at detection levels that are as much as two orders of magnitude lower than those obtained by standard Environmental Protection Agency methods. Nineteen hundred thirty six subtidal sediment samples collected in the sound and the eastern Gulf of Alaska in 1989, 1990, and 1991 were analyzed. Fingerprint analyses of gas chromatography-mass spectrometry data reveal a naturalmore » background of petrogenic and biogenic PAH. Exxon Valdez crude, its weathering products, and diesel fuel refined from Alaska North Slope crude are readily distinguished from the natural seep petroleum background and from each other because of their distinctive PAH distributions. Mixing models were developed to calculate the PAH contributions from each source to each sediment sample. These calculations show that most of the seafloor in PWS contains no detectable hydrocarbons from the Exxon Valdez spill, although elevated concentrations of PAH from seep sources are widespread. In those areas where they were detected, spill hydrocarbons were generally a small increment to the natural petroleum hydrocarbon background. Low levels of Exxon Valdez crude residue were present in 1989 and again in 1990 in nearshore subtidal sediments off some shorelines that had been heavily oiled. By 1991 these crude residues were heavily degraded and even more sporadically distributed. 58 refs., 18 figs., 5 tabs.« less

Cadmium partition in river sediments from an area affected by mining activities.

PubMed

Vasile, Georgiana D; Vlădescu, Luminiţa

2010-08-01

In this paper, the cadmium distribution in Certej River sediments in an area seriously affected by intense mining activities has been studied. The main objective of this study was the evaluation of partition of this metal into different operational defined fractions by sequential extractions. Community Bureau of Reference (BCR) sequential extraction was used to isolate different fractions. The sediment quality was assessed both upstream and downstream the pollution input points, along the Certej River, in order to reveal a possible accumulation of cadmium in sediments and the seasonal changes in cadmium concentrations in BCR sediment phases. Our results reveal that most of the cadmium content is divided between both the soluble and iron and manganese hydrated oxide fractions. Based on total cadmium concentrations in sediments, the enrichment factors were estimated using aluminum as normalizing element and the regression curve Cd/Al corresponding to the geochemical background of the studied area.

The impact of human activities on sediments of San Francisco Bay, California: an overview

USGS Publications Warehouse

van Geen, Alexander; Luoma, Samuel N.

1999-01-01

This note introduces a set of eight papers devoted to a detailed study of two sediment cores from San Francisco Bay with an overview of the region and a chronology of human activities. Data used in this study to constrain the range of sediment ages at different depths include , and  concentrations in the sediment and the  age of shell fragments. In order of first detectable appearance in the record, the indicators of contamination that were analyzed include PAHs>Hg>Ag, Cu, Pb, Zn>DDT, PCB>foraminiferal Cd/Ca. This study also documents a large memory effect for estuarine contamination caused by sediment mixing and resuspension. Once an estuary such as San Francisco Bay has been contaminated, decades must pass before contaminant levels in surface sediment will return to background levels, even if external contaminant inputs have been entirely eliminated.

Impact of mine and natural sources of mercury on water, sediment, and biota in Harley Gulch adjacent to the Abbott-Turkey Run mine, Lake County, California

USGS Publications Warehouse

Rytuba, James J.; Hothem, Roger L.; Brussee, Brianne E.; Goldstein, Daniel N.

2011-01-01

Sediment with high Hg concentration is present throughout the West Fork of Harley Gulch below the mine and in the upper part of the Harley Gulch main stem to just above sample site HG10. At the sample site furthest downstream, HG10, Hg concentration is at background levels, as are cobalt (Co), nickel (Ni), and tungsten (W), indicating that the sediment is not significantly contaminated with Hg from the mine.

Burrow characteristics of the mud shrimp Austinogebia edulis, an ecological engineer causing sediment modification of a tidal flat.

PubMed

Das, Shagnika; Tseng, Li-Chun; Wang, Lan; Hwang, Jiang-Shiou

2017-01-01

The mud shrimp Austinogebia edulis, being abundant in the intertidal zone of western Taiwan, constructs deep burrows (>1 m). This study highlights the potential of mud shrimps to modify sediment characteristics of the tidal flat by its burrowing behavior. We studied the structure of the burrow wall, compared the difference in the sediment composition of the burrow and the background sediment, and compared the organic content inside the burrow wall. This study was carried out from September 2015 to November 2016 in three areas of the western coast of Taiwan, namely Shengang, Hanbow, and Wangong. The present study found significant differences between burrow wall and the burrow lumen. The diameter of the burrow wall was double as wide as the inner burrow lumen at the opening and gradually increased to 10 times of the burrow lumen at 30 cm depth. The burrow wall of A. edulis showed low permeability and increased the sheer strength. Statistically, a significant difference was noticed in the comparison between the sediment composition of the burrow wall and the background (p < 0.05, Student's t-test). An accumulation of 3.63 for fine sand (t = -5.22, p < 0.001, fine sand) and 9 for clay (t = -25.01, p < 0.001, clay) was found in the upper burrow wall of A. edulis. This indicated that they somehow chose finer particles to build burrows. This will gradually change the sediment distribution-vertically and horizontally. The burrow wall consisted of a 24 times higher organic matter content than one individual of mud shrimp. The burrow may provide organic material as a potential food source. The mud shrimp thus transforms the sediment characteristics as an ecological engineer, which is expected to have a significant ecological impact on the ecosystem.

Recent paleorecords document rising mercury contamination in Lake Tanganyika

USGS Publications Warehouse

Conaway, C.H.; Swarzenski, P.W.; Cohen, A.S.

2012-01-01

Recent Lake Tanganyika Hg deposition records were derived using 14C and excess 210Pb geochronometers in sediment cores collected from two contrasting depositional environments: the Kalya Platform, located mid-lake and more removed from watershed impacts, and the Nyasanga/Kahama River delta region, located close to the lake's shoreline north of Kigoma. At the Kalya Platform area, pre-industrial Hg concentrations are 23??0.2ng/g, increasing to 74ng/g in modern surface sediment, and the Hg accumulation rate has increased from 1.0 to 7.2??g/m 2/a from pre-industrial to present, which overall represents a 6-fold increase in Hg concentration and accumulation. At the Nyasanga/Kahama delta region, pre-industrial Hg concentrations are 20??3ng/g, increasing to 46ng/g in surface sediment. Mercury accumulation rate has increased from 30 to 70??g/m 2/a at this site, representing a 2-3-fold increase in Hg concentration and accumulation. There is a lack of correlation between charcoal abundance and Hg accumulation rate in the sediment cores, demonstrating that local biomass burning has little relationship with the observed Hg concentration or Hg accumulation rates. Examined using a sediment focusing-corrected mass accumulation rate approach, the cores have similar anthropogenic atmospheric Hg deposition profiles, suggesting that after accounting for background sediment concentrations the source of accumulating Hg is predominantly atmospheric in origin. In summary, the data document an increase of Hg flux to the Lake Tanganyika ecosystem that is consistent with increasing watershed sediment delivery with background-level Hg contamination, and regional as well as global increases in atmospheric Hg deposition. ?? 2011.

Transport mechanisms of Silver Nanoparticles by runoff - A Flume Experiment

NASA Astrophysics Data System (ADS)

Mahdi Mahdi, Karrar NM; Commelin, Meindert; Peters, Ruud J. B.; Baartman, Jantiene E. M.; Ritsema, Coen; Geissen, Violette

2017-04-01

Silver Nanoparticles (AgNPs) are being used in many products as it has unique antimicrobial-biocidal properties. Through leaching, these particles will reach the soil environment which may affect soil organisms and disrupt plants. This work aims to study the potential transport of AgNPs with water and sediment over the soil surface due to soil erosion by water. This was done in a laboratory setting, using a rainfall simulator and flume. Low AgNPs concentration (50 μg.kg-1) was applied to two soil-flumes with slopes of 20% and 10%. The rainfall was applied in four events of 15 min each with the total amount of rainfall was 15mm in each event. After applying the rainfall, different samples were collected; soil clusters, background (BS) and surface sediments (Sf), from the flume surface, and, Runoff sediments (RS) and water (RW) was collected from the outlet. The results showed that AgNPs were detected in all samples collected, however, AgNPs concentration varied according samples type (soil or water), time of collection (for runoff water and sediment) and the slope of the soil flume. Further, the higher AgNPs concentrations were detected in the background soil (BS); as the BS samples have more finer parts (silt and clay). The AgNPs concentration in the runoff sediments increased with subsequent applied rain events. In addition to that, increasing the slope of the flume from 10% to 20% increased the total AgNPs transported with the runoff sediments by a factor 1.5. The study confirms that AgNPs can be transported over the soil surface by both runoff water and sediments due to erosion.

Spatial distribution of chemical constituents in the Kuskokwim River, Alaska

USGS Publications Warehouse

Wang, Bronwen

1999-01-01

The effects of lithologic changes on the water quality of the Kuskokwim River, Alaska, were evaluated by the U.S. Geological Survey in June 1997. Water, suspended sediments, and bed sediments were sampled from the Kusko-kwim River and from three tributaries, the Holitna River, Red Devil Creek, and Crooked Creek. Dissolved boron, chromium, copper, manganese, zinc, aluminum, lithium, barium, iron, antimony, arsenic, mercury, and strontium were detected. Dissolved manganese and iron concentrations were three and four times higher in the Holitna River than in the Kusko-kwim River. Finely divided ferruginous materials found in the graywacke and shale units of the Kuskokwim Group are the probable source of the iron. The highest concentrations of dissolved strontium and barium were found at McGrath, and the limestone present in the upper basin was the most probable source of strontium. The total mercury concentrations on the Kuskokwim River decreased downstream from McGrath. Dissolved mercury was 24 to 32 percent of the total concentration. The highest concentrations of total mercury, and of dissolved antimony and arsenic were found in Red Devil Creek. The higher concentrations from Red Devil Creek did not affect the main stem mercury transport because the tributary was small relative to the Kuskokwim River. In Red Devil Creek, total mercury exceeded the concentration at which the U.S. Environmental Protection Agency (USEPA) indicates that aquatic life is affected and dissolved arsenic exceeded the USEPA's drinking-water standard. Background mercury and antimony concentrations in bed sediments ranged from 0.09 to 0.15 micrograms per gram for mercury and from 1.6 to 2.1 micrograms per gram for antimony. Background arsenic concentrations were greater than 27 micrograms per gram. Sites near the Red Devil mercury mine had mercury and antimony concentrations greater than background concentrations. These concentrations probably reflect the proximity to the ore body and past mining. Crooked Creek had mercury concentrations greater than the background concentration. The transport of suspended sediment-associated trace elements was lower for all elements in the lower river than in the upper river, indicating storage of sediments and their associated metals within the river system.

Submarine Landslide Hazards Offshore Southern Alaska: Seismic Strengthening Versus Rapid Sedimentation

NASA Astrophysics Data System (ADS)

Sawyer, D.; Reece, R.; Gulick, S. P. S.; Lenz, B. L.

2017-12-01

The southern Alaskan offshore margin is prone to submarine landslides and tsunami hazards due to seismically active plate boundaries and extreme sedimentation rates from glacially enhanced mountain erosion. We examine the submarine landslide potential with new shear strength measurements acquired by Integrated Ocean Drilling Program Expedition 341 on the continental slope and Surveyor Fan. These data reveal lower than expected sediment strength. Contrary to other active margins where seismic strengthening enhances slope stability, the high-sedimentation margin offshore southern Alaska behaves like a passive margin from a shear strength perspective. We interpret that seismic strengthening occurs but is offset by high sedimentation rates and overpressure within the slope and Surveyor Fan. This conclusion is supported because shear strength follows an expected active margin profile outside of the fan, where background sedimentation rates occur. More broadly, seismically active margins with wet-based glaciers are susceptible to submarine landslide hazards because of the combination of high sedimentation rates and earthquake shaking

Geochemistry of polycyclic aromatic hydrocarbons in the bottom sediments of the eastern Arctic shelf

NASA Astrophysics Data System (ADS)

Petrova, V. I.; Batova, G. I.; Kursheva, A. V.; Litvinenko, I. V.; Savinov, V. M.; Savinova, T. N.

2008-04-01

Sources and pathways of supply of polycyclic aromatic hydrocarbons (PAH) in the surface sediments of the Laptev and East Siberian seas were identified based on an analysis of the lithological-geochemical characteristics and distribution of organic matter (OM). The distribution of organic carbon, humic acids, bitumoids, and hydrocarbons demonstrates the determining role of the riverine runoff in the formation of the recent sediments. The total average content of PAH in the sediments of this region approximates 37 ng/g, not exceeding 80 ng/g of dry sediment. The biogenic components of the PAH (alkylphenanthrenes, alkylchrysenes, perylene) dominate in the estuarine-shelf and coastal-shelf sediments enriched with plant detritus and significantly decrease in the pelagic zone. The anthropogenic influence is observed in sediments of the port of Tiksi, where the total content of PAH with dominant pyrogenic components is two orders of magnitude higher as compared with the background values in the study region.

Occurrence of microplastics in the coastal marine environment: First observation on sediment of China.

PubMed

Qiu, Qiongxuan; Peng, Jinping; Yu, Xubiao; Chen, Fangchaizi; Wang, Jundong; Dong, Fenqiang

2015-09-15

Microplastics in sediments from the Beibu Gulf and the coastline of China Sea were investigated to evaluate the occurrence and abundance of microplastics in China for the first time. Microplastics (<5mm) were taken from sediments by a flotation method. The number of microplastics was counted by a fluorescence microscope, an instrument that is rarely used in the detection of microplastics in sediments. This instrument led to results that were satisfactory. Compared with other sampled areas, microplastics were found in massive concentrations in China. Four types of microplastics, HDPE, PET, PE and PS, were identified. The results will provide useful background information for further investigations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Using Passive Samplers to Calculate the Diffusive Flux of DDTs and PCBs from Sediments to Water Column at the Palos Verdes Shelf Superfund Site

EPA Science Inventory

Background/Objectives. The Palos Verdes Shelf (PVS) Superfund site is in over 50 meters of water on the continental shelf and slope off the coast of southern California (USA). The site includes over 25 km2 of sediments contaminated over several decades by municipal treatment pla...

Sizing Determination Final Report

DTIC Science & Technology

1988-02-01

A Name: ERIC WHEATLEY Subject No.: 4 S/N: ------------ Sex.: M Race: BLACK Age...z:ni:zum Frcx-tal Arc - Tahc and -Marker Tool 19.= 6- - B-prozy.ncmatic_ ,’entlon Ar- - T"p_ and Marler Tool ......... .. 26.:; i7 Bitragion Mini-o-u- Frc...tape and Marler Tool ............. 24.5 7 . ilt’-aoion inigmu F-ontal Ar-c - -:•c= Oil- ---................... . ?.. S:-.-_,_ . ................. 1

High Fidelity Modeling of Field Reversed Configuration (FRC) Thrusters

DTIC Science & Technology

2017-04-22

signatures which can be used for direct, non -invasive, comparison with experimental diagnostics can be produced. This research will be directly... experimental campaign is critical to developing general design philosophies for low-power plasmoid formation, the complexity of non -linear plasma processes...advanced space propulsion. The work consists of numerical method development, physical model development, and systematic studies of the non -linear

Simulations of Axisymmetric Erosion in IFR-Transported Beams

DTIC Science & Technology

1989-02-21

be significant only when the pi:,h fr)c, an( indi(t:ve F 7 :pile at th head of the beam are weak, as in * . , ’ c. cf Ini. cirari ft. ’ leri roiir...Baker (AFWL/NTYP) Dr. Muhammad Owais (RAAE) D. Dietz (AFWL/NTYP) Lt Col J. Head Department of Energy R. W. Lemke Washington, DC 20545 Attn: Dr. Wilmot

Distribution and enrichment of heavy metals in Sabratha coastal sediments, Mediterranean Sea, Libya

NASA Astrophysics Data System (ADS)

Nour, Hamdy E.; El-Sorogy, Abdelbaset S.

2017-10-01

In order to assess heavy metal pollutants in Sabratha coastal sediments, Mediterranean Sea, Libya, 30 sediment samples were collected for Fe, Cu, Pb, Mn, Cd, Co, Ni and Zn analysis using Atomic Absorption Spectrometry. The analysis indicated that, the Sabratha 's coastal sediments were enriched with Cd, Pb, Cu, Ni, Co and Zn (EF = 81.48, 17.26, 12.80, 11.42, 9.85 and 8.56 respectively). The highest levels of Mn, Cu, Ni, Pb and Co were recorded nearby the Mellitah complex oil and gas station in the western Libyan region, while the highest levels of Zn and Cd were recorded at the central part of the study area nearby fishing port and Sabratha hospital. Average values of Cd, Pb and Co were mostly higher than the ones recorded from the Arabian and Oman gulfs, the Red Sea, the Gulf of Aqaba, the Caspian Sea, coast of Tanzania and the background shale and the earth's crust. The high levels of most of the studied heavy metals suggested significant anthropogenic sources along Sabratha coast. The results of the present study provide a useful background for further marine studies on the Mediterranean area.

Charge separation and transport of the n=2 instability in C-2 FRC plasmas

NASA Astrophysics Data System (ADS)

Deng, Bihe; Sun, Xuan; Tuszewski, Michel

2012-10-01

Charge separation is critical in the positive feedback loop for gravitational type instabilities to grow [1], such as in the case of the n=2 mode in the C-2 field reversed configuration (FRC) experiment [2]. A fast time response Langmuir probe with minimum perturbation to the plasma is inserted into the edge of the C-2 plasma to measure the plasma floating potential. With the combined plasma wobble motion and spin motion, 2-D scans of the plasma floating potential are obtained, and evidence of charge separation associated with the n=2 instability is observed. The transport due to charge separation is estimated. Charge neutralization can provide an alternative method to stabilize the n=2 mode. An experiment is proposed to test this method with two probes inserted into the plasma from two azimuthally separated ports and an external shorting circuit, to constantly neutralize the charge separation, thus suppress the growth of the n=2 mode. [4pt] [1] R.J. Goldston and P.H. Rutherford, Introduction to Plasma Physics (Institute of Physics Publishing, Bristol, 2000).[0pt] [2]. M.W. Binderbauer et al, Phys. Rev. Lett. 105, 045003 (2010).

Compact toroid injection into C-2U

NASA Astrophysics Data System (ADS)

Roche, Thomas; Gota, H.; Garate, E.; Asai, T.; Matsumoto, T.; Sekiguchi, J.; Putvinski, S.; Allfrey, I.; Beall, M.; Cordero, M.; Granstedt, E.; Kinley, J.; Morehouse, M.; Sheftman, D.; Valentine, T.; Waggoner, W.; the TAE Team

2015-11-01

Sustainment of an advanced neutral beam-driven FRC for a period in excess of 5 ms is the primary goal of the C-2U machine at Tri Alpha Energy. In addition, a criteria for long-term global sustainment of any magnetically confined fusion reactor is particle refueling. To this end, a magnetized coaxial plasma-gun has been developed. Compact toroids (CT) are to be injected perpendicular to the axial magnetic field of C-2U. To simulate this environment, an experimental test-stand has been constructed. A transverse magnetic field of B ~ 1 kG is established (comparable to the C-2U axial field) and CTs are fired across it. As a minimal requirement, the CT must have energy density greater than that of the magnetic field it is to penetrate, i.e., 1/2 ρv2 >=B2 / 2μ0 . This criteria is easily met and indeed the CTs traverse the test-stand field. A preliminary experiment on C-2U shows the CT also capable of penetrating into FRC plasmas and refueling is observed resulting in a 20 - 30% increase in total particle number per single-pulsed CT injection. Results from test-stand and C-2U experiments will be presented.

Rotational stability of a long field-reversed configuration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnes, D. C., E-mail: coronadocon@msn.com; Steinhauer, L. C.

2014-02-15

Rotationally driven modes of long systems with dominantly axial magnetic field are considered. We apply the incompressible model and order axial wavenumber small. A recently developed gyro-viscous model is incorporated. A one-dimensional equilibrium is assumed, but radial profiles are arbitrary. The dominant toroidal (azimuthal) mode numbers ℓ=1 and ℓ=2 modes are examined for a variety of non-reversed (B) and reversed profiles. Previous results for both systems with rigid rotor equilibria are reproduced. New results are obtained by incorporation of finite axial wavenumber and by relaxing the assumption of rigid electron and ion rotation. It is shown that the frequently troublesomemore » ℓ=2 field reversed configuration (FRC) mode is not strongly affected by ion kinetic effects (in contrast to non-reversed cases) and is likely stabilized experimentally only by finite length effects. It is also shown that the ℓ=1 wobble mode has a complicated behavior and is affected by a variety of configuration and profile effects. The rotationally driven ℓ=1 wobble is completely stabilized by strong rotational shear, which is anticipated to be active in high performance FRC experiments. Thus, observed wobble modes in these systems are likely not driven by rotation alone.« less

Cross-separatrix Coupling in Nonlinear Global Electrostatic Turbulent Transport in C-2U

NASA Astrophysics Data System (ADS)

Lau, Calvin; Fulton, Daniel; Bao, Jian; Lin, Zhihong; Binderbauer, Michl; Tajima, Toshiki; Schmitz, Lothar; TAE Team

2017-10-01

In recent years, the progress of the C-2/C-2U advanced beam-driven field-reversed configuration (FRC) experiments at Tri Alpha Energy, Inc. has pushed FRCs to transport limited regimes. Understanding particle and energy transport is a vital step towards an FRC reactor, and two particle-in-cell microturbulence codes, the Gyrokinetic Toroidal Code (GTC) and A New Code (ANC), are being developed and applied toward this goal. Previous local electrostatic GTC simulations find the core to be robustly stable with drift-wave instability only in the scrape-off layer (SOL) region. However, experimental measurements showed fluctuations in both regions; one possibility is that fluctuations in the core originate from the SOL, suggesting the need for non-local simulations with cross-separatrix coupling. Current global ANC simulations with gyrokinetic ions and adiabatic electrons find that non-local effects (1) modify linear growth-rates and frequencies of instabilities and (2) allow instability to move from the unstable SOL to the linearly stable core. Nonlinear spreading is also seen prior to mode saturation. We also report on the progress of the first turbulence simulations in the SOL. This work is supported by the Norman Rostoker Fellowship.

Phenomenology of beam driven modes in the field reversed configuration

NASA Astrophysics Data System (ADS)

Magee, Richard; Bolte, Nathan; Clary, Ryan; Necas, Ales; Korepanov, Sergey; Smirnov, Artem; Thompson, Matthew; Tajima, Toshiki; THE TAE Team

2016-10-01

The C-2U experiment offers a unique plasma environment combining a high beta field reversed configuration (FRC) embedded in a low beta magnetic mirror with high power neutral beam injection. The beams are injected tangentially into a modest magnetic field so that the orbits of the resulting fast ions encircle the entire plasma. These large orbit particles sustain and stabilize the plasma and suppress turbulence. Measurements of magnetic fluctuations at the edge of the plasma reveal the presence of three coherent beam driven modes: a low frequency, chirping mode, a mode near the ion cyclotron frequency, and a high frequency compressional Alfven mode. Remarkably, none of these modes are observed to have a deleterious effect on global plasma confinement. In fact, the cyclotron mode has the beneficial effect of dramatically enhancing the DD fusion reaction rate by drawing a trail from the plasma ion energy distribution on a sub-collisional timescale. In this presentation, we experimentally characterize the beam driven modes in the C-2U FRC with data from multiple diagnostics including magnetics, spectroscopy, neutral particle analyzers and fusion product diagnostics. Results are compared to a particle-in-cell simulation in a simplified geometry.

Comprehensive approach to fast ion measurements in the beam-driven FRC

NASA Astrophysics Data System (ADS)

Magee, Richard; Smirnov, Artem; Onofri, Marco; Dettrick, Sean; Korepanov, Sergey; Knapp, Kurt; the TAE Team

2015-11-01

The C-2U experiment combines tangential neutral beam injection, edge biasing, and advanced recycling control to explore the sustainment of field-reversed configuration (FRC) plasmas. To study fast ion confinement in such advanced, beam-driven FRCs, a synergetic technique was developed that relies on the measurements of the DD fusion reaction products and the hybrid code Q2D, which treats the plasma as a fluid and the fast ions kinetically. Data from calibrated neutron and proton detectors are used in a complementary fashion to constrain the simulations: neutron detectors measure the volume integrated fusion rate to constrain the total number of fast ions, while proton detectors with multiple lines of sight through the plasma constrain the axial profile of fast ions. One application of this technique is the diagnosis of fast ion energy transfer and pitch angle scattering. A parametric numerical study was conducted, in which additional ad hoc loss and scattering terms of varying strengths were introduced in the code and constrained with measurement. Initial results indicate that the energy transfer is predominantly classical, while, in some cases, non-classical pitch angle scattering can be observed.

Miniaturization of a Combination Langmuir/Mach Probe

NASA Astrophysics Data System (ADS)

Melnik, P. A.; Dehart, T.; Lotz, D.

2009-11-01

A combination Langmuir/Mach probe has been developed to measure electron temperature and density as well as ion flow speed in TCSU. The probe is fully translatable allowing it to diagnose all radial locations of the FRC at either the mid-plane, end section, or in the exhaust jets. The 1/4'' probe stalk consists of interlocking boron nitride cylinders which encompass a 1/8'' diameter stainless steel tube that houses the probe wires. In addition to the stainless steel jacket the probe wires are twisted to minimize electromagnetic noise pickup. The tip of this combo probe is composed of a boron nitride housing and eight .020'' diameter tungsten collection leads. In TCSU, the RMF used to form and sustain the FRC makes Langmuir probe measurements difficult. To this end we have developed a drive circuit that will generate the bias voltages necessary for Langmuir probe operation. This bipolar power supply can produce steady voltages up to 200 volts at loads over 1 amp and can be swept at any frequency up to 1.5 MHz. The probe current and bias voltage will be recorded with an amplifier and transmitted via fiber optic to a receiver allowing the signals to be digitized.

Diagnostic Progress and Results on the Magnetized Shock Experiment

NASA Astrophysics Data System (ADS)

Smith, R. J.; Weber, T. E.

2015-11-01

The Magnetized Shock Experiment (MSX) at LANL is reliably producing Field Reversed Configuration (FRC) plasmas spanning peak densities of ~ 1021-23 m-3, combined Te +Ti of 10s-500eV and velocities of 100-300km/s as a means to producing a laboratory supercritical collision-less shock. Visible light images showing discontinuities indicative of shocks and jetting have been obtained on various targets: co-solenoid B field, a metal wall and counter-solenoidal B fields (FRC capture and reconnection). Two chord interferometry, external and internal magnetic probing are routinely employed and x-ray diagnostic capability has recently been added. The pulsed polarimetry technique is being deployed which can measure the local magnetic field using Lidar Thomson scattering. In addition, a fiber optic version of pulsed polarimetry using a new specialty fiber that enhances fiber backscatter with Fiber Bragg Gratings is being developed. Magnetic fields of order ~ 1T have been measured, however a new modified shock chamber geometry and recent machine modifications enabling operation at increased θ-coil voltage are expected to improve translation speed and hence stagnation pressures. Progress on these diagnostics and results will be presented. DOE support Grant No DE-SC00010559.

Employing extant stable carbon isotope data in Gulf of Mexico sedimentary organic matter for oil spill studies

NASA Astrophysics Data System (ADS)

Rosenheim, Brad E.; Pendergraft, Matthew A.; Flowers, George C.; Carney, Robert; Sericano, José L.; Amer, Reda M.; Chanton, Jeff; Dincer, Zeynep; Wade, Terry L.

2016-07-01

We have compiled and mapped available carbon isotope data from sedimentary organic material sampled from the Gulf of Mexico prior to 2010. These data provide a baseline to which any changes in the Gulf of Mexico after the 2010 Deepwater Horizon oil spill can be compared. The mean (±1σ) δ13C values, relative to PDB, are -21.4±1.9‰ (entire Gulf of Mexico), -21.7±1.2‰ (shelf sediments), -20.4±1.6‰ (deepwater sediments), and -25.2±4.1‰ (seep-affected sediments). We compare pre-spill mean δ13C values to carbon isotope measurements of sedimentary organic material from coretop samples collected after the 2010 Deepwater Horizon oil spill. The differences between the mean compiled δ13C values and the post-spill δ13C values are corroborated by qualitative relationships with the concentration of polycyclic aromatic hydrocarbons (PAHs), a proxy for oil contamination, in the sediment. The relationships between δ13C of the sedimentary organic material and PAH concentrations allow estimation of background levels of PAHs on the shelf and in the deep Gulf of Mexico. Higher background levels of PAH on the shelf likely relate to Mississippi River outflow and its deposition of petrogenic PAH in riverine sediments.

Natural-abundance stable carbon isotopes of small-subunit ribosomal RNA (SSU rRNA) from Guaymas Basin (Mexico)

NASA Astrophysics Data System (ADS)

MacGregor, B. J.; Mendlovitz, H.; Albert, D.; Teske, A. P.

2012-12-01

Small-subunit ribosomal RNA (SSU rRNA) is a phylogenetically informative molecule found in all species. Because it is poorly preserved in most environments, it is a useful marker for active microbial populations. We are using the natural-abundance stable carbon isotopic composition of specific microbial groups to help identify the carbon substrates contributing to microbial biomass in a variety of marine environments. At Guaymas Basin, hydrothermal fluids interact with abundant sedimentary organic carbon to produce natural gas and petroleum. Where this reaches the sediment surface, it can support dense patches of seafloor life, including Beggiatoa mats. We report here on the stable carbon isotopic composition of SSU rRNA from a Beggiatoa mat transect, a cold background site, a warm site with high oil concentration, and a second Beggiatoa mat. The central part of the transect mat overlay the steepest temperature gradient, and was visually dominated by orange Beggiatoa. This was fringed by white Beggiatoa mat and bare, but still warm, sediment. Methane concentrations were saturating beneath the orange and white mats and at the oily site, lower beneath bare sediment, and below detection at the background site. Our initial hypotheses were that rRNA isotopic composition would be strongly influenced by methane supply, and that archaeal rRNA might be lighter than bacterial due to contributions from methanogens and anaerobic methane oxidizers. We used biotin-labeled oligonucleotides to capture Bacterial and Archaeal SSU rRNA for isotopic determination. Background-site rRNA was isotopically heaviest, and bacterial RNA from below 2 cm at the oily site was lightest, consistent with control by methane. Within the transect mat, however, the pattern was more complicated; at some sediment depths, rRNA from the mat periphery was isotopically lightest. Part of this may be due to the spatially and temporally variable paths followed by hydrothermal fluid, which can include horizontal flow. There was no consistent isotopic difference between rRNAs captured by the two probes, although RNA recoveries were too low for isotopic determinations at depths where methanogens and methane oxidizers are expected. Our prediction that rRNA stable carbon isotopic composition would correlate with methane supply was borne out by the comparison between background and mat sediments, but may be an oversimplification for sites within hydrothermal features. Future work will include the isotopic characterization of other potential carbon substrates, such as acetate. We are also investigating cold-seep sediments and brine pools in the Gulf of Mexico, where methane is significantly more 13C-depleted than at Guaymas Basin and may therefore leave a stronger imprint on microbial biomass.table carbon isotopes of rRNA captured with Bacterial and Archaeal probes at mat transect and background sites.

Biogeochemical and microbiological characteristic of the pockmark sediments, the Gdansk Deep, The Baltic Sea

NASA Astrophysics Data System (ADS)

Pimenov, Nikolay; Kanapatskiy, Timur; Sivkov, Vadim; Toshchakov, Stepan; Korzhenkov, Aleksei; Ulyanova, Marina

2016-04-01

Comparison of the biogeochemical and microbial features was done for the gas-bearing and background sediments as well as near-bottom water of the Gdansk Deep, The Baltic Sea. Data were received in October, 2015 during 64th cruise of the R/V Akademik Mstislav Keldysh. Gas-bearing sediments were sampled within the known pockmark (Gas-Point, depth 94 m). Background sediments area (BG-Point, depth 86 m) was located several km off the pockmark area. The sulphate concentration in the pore water of the surface sediment layer (0-5 cm) of Gas-Point was 9,7 mmol/l, and sharply decreased with depth (did not exceed 1 mmol/l deeper than 50 cm). The sulphate concentration decrease at BG-Point also took place but was not so considerable. Sulphate concentration decrease is typical for the organic rich sediments of the high productive areas, both as for the methane seep areas. Fast sulphate depletion occurs due to active processes of its microbial reduction by consortium of the sulphate-reduction bacteria, which may use low-molecular organic compounds or hydrogen, formed at the different stages of the organic matter destruction; as well as within the process of the anaerobic methane oxidation by consortium of the methane-trophic archaea and sulphate-reduction bacteria. Together with sulphate concentration decrease the methane content increase, typical for the marine sediments, occurred. At the Gas-Point the methane concentration varied within 10 μmol/dm3 in the surface layer till its maximum at sediment horizon of 65 cm (5 mmol/dm3), and decreased to 1.5 mmol/dm3 at depth of 300 cm. The BG-Point maximum values were defined at sediment horizon 6 cm (2,6 μmol/dm3). Methane sulfate transition zone at the Gas-Point sediments was at 25-35 cm depth; whereas it was not defined at the BG-Point mud. High methane concentration in the gas-bearing sediments results in the formation of the methane seep from the sediments to the near-bottom water. So the Gas-Point near-bottom waters were characterized by high methane concentration (0.36-0.50 μmol/l) even in the water 2-5 m above the bottom (0.08-0.28 μmol/l), whereas at the BG-Point sediments methane concentration in the near-bottom water was 0.06-0.08 μmol/l. In order to get insights into the structure of microbial community responsible for realization of these redox processes we performed microbial community profiling using high-throughput 16S amplicon sequencing. DNA was extracted from sediments and water column in pockmark and background zones. NGS libraries were prepared with fusion primers for V4 variable region (Caporaso et al., 2012) and sequenced on the MiSeq system. Results well correlated with new data obtained from the analysis of the intensity of microbial processes. The study was financed by the Russian Scientific Fund (grant 14-37-00047). Caporaso JG, Lauber CL, Walters WA, Berg-Lyons D, Huntley J, Fierer N, Owens SM, Betley J, Fraser L, Bauer M, Gormley N, Gilbert JA, Smith G, Knight R. Ultra-high-throughput microbial community analysis on the Illumina HiSeq and MiSeq platforms. ISME J. 2012 Aug;6(8):1621-4

Modeled summer background concentration nutrients and suspended sediment in the mid-continent (USA) great rivers

EPA Science Inventory

We used regression models to predict background concentration of four water quality indictors: total nitrogen (N), total phosphorus (P), chloride, and total suspended solids (TSS), in the mid-continent (USA) great rivers, the Upper Mississippi, the Lower Missouri, and the Ohio. F...

Distribution of Cr, Pb, Cd, Zn, Fe and Mn in Lake Victoria sediments, East Africa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onyari, J.M.; Wandiga, S.O.

1989-06-01

The presence of many metals at trace or ultra-trace levels in the human environment has received increased global attention. Sediments as a sink for pollutants are widely recognized pollution sources and diagenesis and biochemical transformations within the sediment may mobilize pollutants posing a threat to a wider biological community. The natural (background) concentrations of heavy metals in lake sediments can be estimated either by analysis of surface sediments in non-polluted regions or by analysis of core samples antedating modern pollution. The distribution pattern of heavy metals in tropical freshwater systems has been little studied. The authors found increased concentrations ofmore » lead and other trace metals in Lake Victoria. Thus this study was initiated in order to further investigate the distribution patterns of lead and other metals in Lake Victoria.« less

Total petroleum hydrocarbons in sediments from the coastline and mangroves of the northern Persian Gulf.

PubMed

Mohebbi-Nozar, Seyedeh Laili; Zakaria, Mohamad Pauzi; Ismail, Wan Ruslan; Mortazawi, Mohammad Seddiq; Salimizadeh, Maryam; Momeni, Mohammad; Akbarzadeh, Gholamali

2015-06-15

To provide baseline information for the marine ecosystem of Hormozgan province, the distribution of petroleum hydrocarbons was evaluated in 52 stations involved in the mangrove and coastline ecosystem. Coastline sampling sites included areas facing harbor, river, domestic and industrial discharge. Sediment samples were analyzed based on ultraviolet fluorescence spectroscopy. Petroleum hydrocarbons showed narrow variations ranging from non-detectable (ND) to 1.71 and from 0.2 to 0.63μg/g dry weight for coastline and mangrove sediments, respectively. The detected concentrations for total petroleum hydrocarbons were lower than guideline values for ecological risk. Furthermore, the minimum environmental risk was confirmed by background levels for the Persian Gulf, the Sea of Oman, and detected values for reference areas. The results were regarded as background data in the studied area, and, considering the rapid expansion of activities related to the petroleum industry in Hormozgan province, the continuous monitoring of pollutants is recommended. Copyright © 2015 Elsevier Ltd. All rights reserved.

Macrofaunal recolonization of copper-contaminated sediments in San Diego Bay.

PubMed

Neira, Carlos; Mendoza, Guillermo; Porrachia, Magali; Stransky, Chris; Levin, Lisa A

2015-12-30

Effects of Cu-loading on macrofaunal recolonization were examined in Shelter Island Yacht Basin (San Diego Bay, California). Sediments with high and low Cu levels were defaunated and Cu-spiked, translocated, and then placed back into the environment. These demonstrated that the alteration observed in benthic communities associated with Cu contamination occurs during initial recolonization. After a 3-month exposure to sediments with varying Cu levels, two primary colonizing communities were identified: (1) a "mouth assemblage" resembling adjacent background fauna associated with low-Cu levels that was more diverse and predominantly dominated by surface- and subsurface-deposit feeders, burrowers, and tube builders, and (2) a "head assemblage" resembling adjacent background fauna associated with high-Cu concentrations, with few dominant species and an increasing importance of carnivores and mobile epifauna. Cu loading can cause reduced biodiversity and lower structural complexity that may last several months if high concentrations persist, with a direct effect on community functioning. Copyright © 2015 Elsevier Ltd. All rights reserved.

Total deposition of ultrafine particles in the lungs of healthy men and women: experimental and theoretical results

PubMed Central

2016-01-01

Background Inhaled ultrafine particles (UFP) may induce greater adverse respiratory effects than larger particles occurring in the ambient atmosphere. Due to this potential of UFP to act as triggers for diverse lung injuries medical as well as physical research has been increasingly focused on the exact deposition behavior of the particles in lungs of various probands. Main purpose of the present study was the presentation of experimental and theoretical data of total, regional, and local UFP deposition in the lungs of men and women. Methods Both experiments and theoretical simulations were carried out by using particle sizes of 0.04, 0.06, 0.08, and 0.10 µm [number median diameters (NMD)]. Inhalation of UFP took place by application of predefined tidal volumes (500, 750, and 1,000 mL) and respiratory flow rates (150, 250, 375, and 500 mL·s−1). For male subjects a functional residual capacity (FRC) of 3,911±892 mL was measured, whereas female probands had a FRC of 3,314±547 mL. Theoretical predictions were based on (I) a stochastic model of the tracheobronchial tree; (II) particle transport computations according to a random walk algorithm; and (III) empirical formulae for the description of UFP deposition. Results Total deposition fractions (TDF) are marked by a continuous diminution with increasing particle size. Whilst particles measuring 0.04 µm in size deposit in the respiratory tract by 40–70%, particles with a size of 0.10 µm exhibit deposition values ranging from 20% to 45%. Except for the largest particles studied here TDF of female probands are higher than those obtained for male probands. Differences between experimental and theoretical results are most significant for 0.10 µm particles, but never exceed 20%. Predictions of regional (extrathoracic, tracheobronchial, alveolar) UFP deposition show clearly that females tend to develop higher tracheobronchial and alveolar deposition fractions than males. This discrepancy is also confirmed by airway generation-specific deposition, which is permanently higher in women than in men. Conclusions From the experimental data and modeling predictions it can be concluded that females bear a slightly higher potential to develop lung insufficiencies after exposure to UFP than males. Besides higher deposition fractions occurring in female subjects, also total lung deposition dose is noticeably enhanced. PMID:27429960

Nature and origin of the sedimentary pile subducting in the Nankai Through

NASA Astrophysics Data System (ADS)

Chauvel, C.; Garcon, M.; Yobregat, E.; Chipoulet, C.; Labanieh, S.

2013-12-01

Nd-Hf isotopes and trace and major element concentrations were measured on bulk sediments recovered at Site C0012 during IODP Expedition 322 and 333 in the Shikoku basin. We analyzed the composition of different lithologies such as clay, claystone, sand, sandstone, and ash layers, all through the sedimentary pile, from the surface to the sediment-basalt interface, in order to identify compositional trends and source variations with depth. Major and trace element contents of the background sediments (hemipelagic mudstone) are very homogenous and span a relatively small range of values throughout the entire sedimentary pile. Their composition resembles that of the average upper continental crust of Rudnick and Gao (2003, Treatise on Geochemistry, Vol.3, p. 1-64). Nd and Hf isotopes are more variable, relatively unradiogenic (-8 < ɛNd < -3 ; -4 < ɛHf < +5) but display no systematic variations with depth (Fig. 1). Such isotopic compositions indicate that the background sedimentation of the Shikoku basin may consist of volcaniclastic material from the Izu-Bonin and/or Ryukyu arcs, detrital material eroded from SW Japan and relatively high amount of an evolved continental-derived component, probably Chinese loess as already suggested by Mahomet (2005, Sediment. Geol., 182, p.183-199). Compared to the background sedimentation, volcanic ash layers and volcaniclastic sandstones have very different trace element patterns and more radiogenic Nd-Hf isotopic signature (Fig. 1). Our results allow us to distinguish at least two different volcanic sources for these deposits. At the bottom of the sedimentary pile, siliciclastic sandstones with a mid-Miocene age are present; they have remarkably low ɛNd and ɛHf values (i.e. ɛNd < -8 and ɛHf < -5). Such isotopic compositions clearly demonstrate that their source cannot be the Japanese mainland, as suggested by previous studies (e.g. Underwood et al, 2009, Exp.322 PR ; Fergusson, 2003, Proc. ODP, Sci. Results 190/196). These sandstones are also too coarse to result from an accumulation of Chinese loess transported by wind (particles usually finer than 40 μm). Given the location of the Shikoku basin at 15Ma, we suggest that the siliciclastic sandstones mainly consists of detrital materials transported by Chinese rivers up to the sea in the Shikoku basin. Variations of ɛNd as a function of depth. Potential sediment sources are indicated by color bands

Sediment quality in the north coastal basin of Massachusetts, 2003

USGS Publications Warehouse

Breault, Robert F.; Ashman, Mary S.; Heath, Douglas

2004-01-01

The U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, completed a reconnaissance-level study of bottom-sediment quality in selected lakes, rivers, and estuaries in the North Coastal Basin of Massachusetts. Bottom-sediment grab samples were collected from 20 sites in the North River, Lake Quannapowitt, Saugus River, Mill River, Shute Brook, Sea Plane Basin, Pines River, and Bear Creek. The samples were tested for various types of potentially harmful contaminants? including 33 elements, 17 polyaromatic hydrocarbons (PAHs), 22 organochlorine pesticides, and 7 polychlorinated biphenyl (PCB) mixtures (Aroclors)?to benthic organisms (bottom-dwelling) and humans. The results were compared among sampling sites, to background concentrations, and to concen-trations measured in other urban rivers, and sediment-quality guidelines were used to predict toxicity at the sampling sites to benthic organisms and humans. Because there are no standards for human toxicity for aquatic sediment, standards for contaminated upland soil were used. Contaminant concentrations measured in sediment collected from the North Coastal Basin generally were equal to or greater than concentrations in sediment from uncontaminated rivers throughout New England. Contaminants in North Coastal Basin sediment with elevated concentrations (above back-ground levels) included arsenic, chromium, copper, lead, nickel, and zinc, some of the PAHs, dichlorodiphenyltrichloro-ethane (DDT) and its metabolites, and dieldrin. No PCBs were measured above the detection limits. Measured concentrations of arsenic, chromium, and lead were also generally greater than those measured in other urban rivers throughout the conter-minous United States. With one exception (arsenic), local con-centrations measured in sediment samples collected from the North Coastal Basin were lower than concentrations measured in sediment collected from two of three urban rivers draining to Boston Harbor. The probable toxicity to benthic organisms ranged from about 33 to 91 percent across the study area. Of the elements analyzed, antimony, arsenic, beryllium, and lead exceeded the soil standards for risk to human health. Of the PAHs analyzed, four also exceeded soil standards. Organochlorine pesticide concentrations, however, were not high enough relative to the soil standards to pose a risk to human health. Some trace element and some organic compound concentrations in bottom sediment may be toxic to aquatic organisms and may pose a risk to human health.

Magnetized Target Fusion - Field Reversed Configuration Formation and Injection (MTF-FRC)

DTIC Science & Technology

2009-11-06

from accidental breakage and personnel from injury in that event. The pumps for the vacuum system included a Varian dry scroll pump that was...a dry scroll (oil-free) mechanical pump could be used, as mTorr pressures would be sufficient for the vacuum switch voltage hold-off and operation...56 FIGURE 46. ROUGHING PUMP AND VACUUM -GAUGE CONTROLLERS BENEATH THETA COIL CABLE HEADER

High Fidelity Modeling of Field-Reversed Configuration (FRC) Thrusters (Briefing Charts)

DTIC Science & Technology

2017-05-24

Converged Math → Irrelevant Solutions? Validation: Fluids Example Stoke’s Flow MARTIN, SOUSA, TRAN (AFRL/RQRS) DISTRIBUTION A - APPROVED FOR PUBLIC RELEASE...Convergence Tests Converged Math → Irrelevant Solutions? Must be Aware of Valid Assumption Regions Validation: Fluids Example Stoke’s Flow Potential...AND VALIDATION Verification: Asymptotic Models → Analytical Solutions Yields Exact Convergence Tests Converged Math → Irrelevant Solutions? Must be

Performance Assessment of Discontinuous Fibers in Fiber Reinforced Concrete: Current State-of-the-Art

DTIC Science & Technology

2017-07-01

this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY...non-destructively evaluate fiber distributions, orientation, and FRC posttest damage. This technique allows for a closer to meso scale investigation...performance all the while optimizing the material and improving desired performance by designing materials based on individual constituent

Comparative Analysis of Emergency Response Operations: Haiti Earthquake in January 2010 and Pakistan’s Flood in 2010

DTIC Science & Technology

2011-09-01

Earthquake, Pakistan, Flood, Emergency Response Operations, International Community, HA/DR, United Nations , FRC, NDMA , ICT 16. PRICE CODE 17. SECURITY...Registration Authority NATO North Atlantic Treaty Organization NDMA National Disaster and Management Authority NDMC National Disaster Management...complicates relief efforts. 6 NDMA Pakistan, “Pakistan Floods-Summary of Damages,” No Author. Accessed 24

Complete genome sequence of Cupriavidus basilensis 4G11, isolated from the Oak Ridge Field Research Center site

DOE PAGES

Ray, Jayashree; Waters, R. Jordan; Skerker, Jeffrey M.; ...

2015-05-14

Cupriavidus basilensis 4G11 was isolated from groundwater at the Oak Ridge Field Research Center (FRC) site. Here, we report the complete genome sequence and annotation of Cupriavidus basilensis 4G11. The genome contains 8,421,483 bp, 7,661 predicted protein-coding genes, and a total GC content of 64.4%.

Lawn Care Pesticides. Risks Remain Uncertain While Prohibited Safety Claims Continue

DTIC Science & Technology

1990-03-23

Trade Commission (FrC), under its own legislative authority to protect consumers against false and deceptive advertising , can take enforcement action...vides to the public about the safety of its products, federal enforcement actions taken against lawn care pesticide safety advertising claims, and...in reassessing the risks of these pesticides. FIFRA also authorizes EPA to take enforcement action against advertising claims made by pesticide

Utility of Acoustic Pharyngometry for the Diagnosis of Obstructive Sleep Apnea.

PubMed

Kendzerska, Tetyana; Grewal, Monica; Ryan, Clodagh M

2016-11-01

Owing to resource limitations, the testing of patients for obstructive sleep apnea (OSA) is often delayed. There is a need to accurately triage and expedite testing in those with a high pretest probability of OSA. Acoustic pharyngometry is a simple, noninvasive technique used to assess the upper airway cross-sectional area (UA-XSA), which is known to be reduced in those with OSA. To determine the discriminative ability and predictive value of UA-XSA measurements by acoustic pharyngometry for OSA. We conducted a cross-sectional study with a clinical cohort of consecutive adults with suspected OSA who had undergone both polysomnography and acoustic pharyngometry. OSA was defined as an apnea-hypopnea index greater than or equal to 5. Multivariable logistic regression analyses and receiver operating characteristic curves were used. The cohort included 576 subjects, 87% of whom had OSA and 64% of whom were men. The subjects' median body mass index (BMI) was 30.3 kg/m 2 , and their median age was 57 years. The median UA-XSA at FRC when sitting was significantly smaller in those with OSA compared with those without OSA (3.3 cm 2 [interquartile range, 2.7-3.8] vs. 3.7 cm 2 [interquartile range, of 2.9-4.2]). When the analysis was controlled for age, sex, BMI, and comorbidities, the odds of OSA increased for every 1-cm 2 decrease in the mean UA-XSA FRC when sitting (odds ratio, 1.62; 95% confidence interval, 1.23-2.13). The mean UA-XSA provided fair discrimination for OSA (area under the curve, 0.60). A cutoff value of 3.75 cm 2 , the point with the best sum of sensitivity and specificity, had sensitivity of 73% and specificity of 46%. The magnitude of the incremental discriminative value of UA-XSA over clinical variables (age, sex, BMI, and comorbidities) was small and nonsignificant (P = 0.5). The mean UA-XSA at FRC when sitting or supine provided no further significant advantage over clinical variables for the discernment of OSA.

Research pilot Fred Haise

NASA Image and Video Library

1966-04-07

Fred W. Haise Jr. was a research pilot and an astronaut for the National Aeronautics and Space Administration from 1959 to 1979. He began flying at the Lewis Research Center in Cleveland, Ohio (today the Glenn Research Center), in 1959. He became a research pilot at the NASA Flight Research Center (FRC), Edwards, Calif., in 1963, serving NASA in that position for three years until being selected to be an astronaut in 1966 His best-known assignment at the FRC (later redesignated the Dryden Flight Research Center) was as a lifting body pilot. Shortly after flying the M2-F1 on a car tow to about 25 feet on April 22, 1966, he was assigned as an astronaut to the Johnson Space Center in Houston, Texas. While at the FRC he had also flown a variety of other research and support aircraft, including the variable-stability T-33A to simulate the M2-F2 heavyweight lifting body, some light aircraft including the Piper PA-30 to evaluate their handling qualities, the Apache helicopter, the Aero Commander, the Cessna 310, the Douglas F5D, the Lockheed F-104 and T-33, the Cessna T-37, and the Douglas C-47. After becoming an astronaut, Haise served as a backup crewmember for the Apollo 8, 11, and 16 missions. He flew on the aborted Apollo 13 lunar mission in 1970, spending 142 hours and 54 minutes in space before returning safely to Earth. In 1977, he was the commander of three free flights of the Space Shuttle prototype Enterprise when it flew its Approach and Landing Tests at Edwards Air Force Base, Calif. Meanwhile, from April 1973 to January 1976, Haise served as the Technical Assistant to the Manager of the Space Shuttle Orbiter Project. In 1979, he left NASA to become the Vice President for Space Programs with the Grumman Aerospace Corporation. He then served as President of Grumman Technical Services, an operating division of Northrop Grumman Corporation, from January 1992 until his retirement. Haise was born in Biloxi, Miss., on November 14, 1933. He underwent flight traini

Additive negative effects of anthropogenic sedimentation and warming on the survival of coral recruits.

PubMed

Fourney, Francesca; Figueiredo, Joana

2017-09-28

Corals worldwide are facing population declines due to global climate change and local anthropogenic impacts. Global climate change effects are hard to tackle but recent studies show that some coral species can better handle climate change stress when provided with additional energy resources. The local stressor that most undermines energy acquisition is sedimentation because it impedes coral heterotrophic feeding and their ability to photosynthesize. To investigate if reducing local sedimentation will enable corals to better endure ocean warming, we quantitatively assessed the combined effects of increased temperature and sedimentation (concentration and turbidity) on the survival of coral recruits of the species, Porites astreoides. We used sediment from a reef and a boat basin to mimic natural sediment (coarse) and anthropogenic (fine) sediment (common in dredging), respectively. Natural sediment did not negatively impact coral survival, but anthropogenic sediment did. We found that the capacity of coral recruits to survive under warmer temperatures is less compromised when anthropogenic sedimentation is maintained at the lowest level (30 mg.cm -2 ). Our study suggests that a reduction of US-EPA allowable turbidity from 29 Nephelometric Turbidity Units (NTU) above background to less than 7 NTU near coral reefs would facilitate coral recruit survival under current and higher temperatures.

Tracking the fate of mercury in the fish and bottom sediments of Minamata Bay, Japan, using stable mercury isotopes.

PubMed

Balogh, Steven J; Tsui, Martin Tsz-Ki; Blum, Joel D; Matsuyama, Akito; Woerndle, Glenn E; Yano, Shinichiro; Tada, Akihide

2015-05-05

Between 1932 and 1968, industrial wastewater containing methylmercury (MeHg) and other mercury (Hg) compounds was discharged directly into Minamata Bay, Japan, seriously contaminating the fishery. Thousands of people who consumed tainted fish and shellfish developed a neurological disorder now known as Minamata disease. Concentrations of total mercury (THg) in recent fish and sediment samples from Minamata Bay remain higher than those in other Japanese coastal waters, and elevated concentrations of THg in sediments in the greater Yatsushiro Sea suggest that Hg has moved beyond the bay. We measured stable Hg isotope ratios in sediment cores from Minamata Bay and the southern Yatsushiro Sea and in archived fish from Minamata Bay dating from 1978 to 2013. Values of δ(202)Hg and Δ(199)Hg in Yatsushiro Sea surface sediments were indistinguishable from those in highly contaminated Minamata Bay sediments but distinct from and nonoverlapping with values in background (noncontaminated) sediments. We conclude that stable Hg isotope data can be used to track Minamata Bay Hg as it moves into the greater Yatsushiro Sea. In addition, our data suggest that MeHg is produced in bottom sediments and enters the food web without substantial prior photodegradation, possibly in sediment porewaters or near the sediment-water interface.

Characteristics of Heavy Metals and Pb Isotopic Composition in Sediments Collected from the Tributaries in Three Gorges Reservoir, China

PubMed Central

Gao, Bo; Zhou, Huaidong; Huang, Yong; Wang, Yuchun; Gao, Jijun; Liu, Xiaobo

2014-01-01

The concentrations, distribution, accumulation, and potential ecological risk of heavy metals (Cr, Cu, Zn, Ni, As, Pb, Cd, and Hg) in sediments from the Three Gorges Reservoir (TGR) tributaries were determined and studied. Pb isotopic compositions in sediments were also measured to effectively identify the potential Pb sources. The results showed that the average concentrations of heavy metals in sediment of TGR tributaries were higher than the local background values of soils and sediments in China. The assessment by Geoaccumulation Index indicated that Cu, Ni, and Hg were at the “slightly polluted” level and Cd was ranked as the “moderately polluted” level in tributary sediments of TGR. The assessment by Potential Ecological Risk Index showed that Hg and Cd were the predominant elements in tributary sediments in TGR. The Pb isotopic ratios in sediments varied from 1.171 to 1.202 for 206Pb/207Pb and from 2.459 to 2.482 for 208Pb/207Pb in TGR. All Pb isotopic ratios in sediments were similar to those from coal combustion, lead ores (the mining activities and smelting process), and cement material, indicating that these anthropogenic inputs may be the main sources for Pb pollution in sediments of TGR tributaries. PMID:24624045

Chronic toxicity of copper to five benthic invertebrates in laboratory-formulated sediment: sensitivity comparison and preliminary risk assessment.

PubMed

Roman, Yblin E; De Schamphelaere, Karel A C; Nguyen, Lien T H; Janssen, Colin R

2007-11-15

Five benthic organisms commonly used for sediment toxicity testing were chronically (28 to 35 days) exposed to copper in standard laboratory-formulated sediment (following Organization for Economic Cooperation and Development guidelines) and lethal and sub-lethal toxicities were evaluated. Sub-lethal endpoints considered were reproduction and biomass production for Lumbriculus variegatus, growth and reproduction for Tubifex tubifex, growth and emergence for Chironomus riparius, and growth for Gammarus pulex and Hyalella azteca. Expressed on whole-sediment basis the observed lethal sensitivity ranking (from most to least sensitive) was: G. pulex>L. variegatus>H. azteca=C. riparius=T. tubifex, with median chronic lethal concentrations (LC50) between 151 and 327 mg/kg dry wt. The sub-lethal sensitivity ranking (from most to least sensitive, with the most sensitive endpoint between parentheses): C. riparius (emergence)>T. tubifex (reproduction)=L. variegatus (reproduction)>G. pulex (growth)>H. azteca (growth), with median effective concentrations (EC50) between 59.2 and 194 mg/kg dry wt. No observed effect concentrations (NOEC) or 10% effective concentrations (EC10) for the five benthic invertebrates were used to perform a preliminary risk assessment for copper in freshwater sediment by means of (a) the "assessment factor approach" or (b) the statistical extrapolation approach (species sensitivity distribution). Depending on the data (NOEC or EC10) and the methodology used, we calculated a Predicted No Effect Concentration (PNEC) for sediment between 3.3 and 47.1 mg Cu/dry wt. This range is similar to the range of natural (geochemical) background concentrations of copper in sediments in Europe, i.e. 90% of sediments have a concentration between 5 and 49 mg Cu/kg dry wt. A detailed analysis of the outcome of this preliminary exercise highlighted that multiple issues need to be explored for achieving a scientifically more sound risk assessment and for the development of robust sediment quality criteria for copper, including (i) the use of the assessment factor approach vs. the statistical extrapolation approach, (ii) the importance of bioavailability modifying factors (e.g., organic carbon, acid volatile sulfide), and (iii) the influence of prevailing geochemical (bioavailable) background concentrations on the copper sensitivity of local benthic biota.

Occurrence and distribution of selected heavy metals in the surface sediments of South Brittany coastal waters: An assessment using pollution indicators

NASA Astrophysics Data System (ADS)

Ong, M. C.; Menier, D.; Noor Azhar, M. S.; Dupont, V.; Révillon, S.

2012-04-01

In order to avoid the pollution of heavy metals in South Brittany water, it is necessary to establish the data and understand the mechanisms influencing the distribution of heavy metals of the area. One of the aims of this work was to assess heavy metals contamination in Gulf of Morbihan and Quiberon Bay. Another aim was to use interpolation surfaces per metals to assess the contamination separately per metal. A total of 196 bottom sediment samples were collected from the coastal waters in order to determine the spatial concentration of Cr, Mn, Co, Cu, Zn, Cd and Pb by Inductively Coupled Plasma Mass Spectrometry (ICPMS) after acid digestion. The average heavy metal concentrations are ranked as follows: Mn>Zn>Cr>Pb>Cu>Cu>Cd. In the gulf, metal enrichments observed compared to the bay environment may due river run-off from three major river (Auray, Le Marle and Novalo rivers) which carried municipal waste and maritime activities along the coastal area within the gulf. Beside those factors, the natural factors such as the sheltered basin morphology itself, fine sediment and low hydrodynamic regime which favour the in situ accumulation of pollutants. The level of pollution levels attributed to heavy metals was evaluated using several pollution indicators in order to determine anthropogenically derived sediment contamination. Comparison to sediment quality guidelines (SQGs), enrichment factors (EFs), index of geoaccumulation (Igeo) and contamination factors (CF) based on reference element and background value to compensate for the influence of the natural variability in sediment mineralogy and to assess whether the concentration observed in surface sediment represent background and contaminated levels and visualize using ArcGIS software. These analyses validated that the bottom sediment only enriched in Pb and the other metals in most sample are not due to artificial contamination. Overall, geochemistry of the samples show the effect of both natural and anthropogenic inputs to the catchment, however, natural processes are more dominant than anthropogenic inputs in concentrating metals in the sediment.

Improvement of suspended sediment concentration estimation for the Yarlung Zangbo river

NASA Astrophysics Data System (ADS)

Zeng, C.; Zhang, F.

2017-12-01

Suspended sediment load of a river represents integrated results of soil erosion, ecosystem variation and landform change occurring within basin over a specified period. Accurate estimation of suspended sediment concentration is important for calculating suspended sediment load, therefore is helpful for evaluating the impact of natural and anthropogenic factors on earth system processes under the background of global climate change. However, long-term observation of suspended sediment concentration usually very difficult in harsh condition areas e.g. rivers on the Tibet Plateau. This study proposed two sediment rating curve subdivision methods, the flood rank method and suspended sediment concentration stages method, to improve the estimations of daily suspended sediment concentration of the Yarlung Zangbo river during 2007 to 2009. The flood rank method, hypothesized that the higher water flow with larger erosive power can mobilize sediment sources not available during lower flows, suitable for application where sediments were mainly transported by first few flood events. The suspended sediment concentration stages method, assumed that precipitation is the dominating driving force of sediment erosion and transport processes during the flooding periods, suitable for application where soil erosion was closely related to precipitation events. Compared to traditional sediment rating curve and subdivision methods, results showed that the proposed methods can improve suspended sediment concentration and subsequent suspended sediment load estimations in the middle reach of the Yarlung Zangbo river with higher coefficients of determination (R2) and Nash-Sutcliffe efficiency coefficients (NSE), and yielded smaller bias (BIAS) and root-mean-square errors (RMSE). This study can provide guidelines for regional ecological and environmental management.

Source apportionment and pollution evaluation of heavy metals in water and sediments of Buriganga River, Bangladesh, using multivariate analysis and pollution evaluation indices.

PubMed

Bhuiyan, Mohammad Amir Hossain; Dampare, Samuel B; Islam, M A; Suzuki, Shigeyuki

2015-01-01

Concentrations of heavy metals in water and sediment samples of Buriganga River in the capital city Dhaka, Bangladesh, were studied to understand the level of heavy metals and their source apportionment. The results showed that the mean concentrations of heavy metals both in water and sediment samples were very high and, in most cases, exceeded the permissible limits recommended by the Bangladesh government and other international organizations. Significantly higher concentrations of Pb, Cr, Mn, Co, Ni, Cu, Zn, As, and Cd were found in sediment samples. However, average concentrations of metals both in water and sediment samples were above the effect range median. The heavy metal pollution index (HPI) and degree of contamination (Cd) yielded different results in water samples despite significant correlations between them. The heavy metal evaluation index (HEI) showed strong correlations with HPI and Cd and provided better assessment of pollution levels. The enrichment factor (EF) and geoaccumulation index (Igeo) showed the elevated value of Cr, Pb, and Cd in access of background values. The measured elements were subjected to positive matrix factorization (PMF) and examining correlations in order to explain the content, behavior, and source apportionment of metals. PMF resulted in a successful partitioning of variances into sources related to background geochemistry and contaminant influences. However, the PMF approach successfully demarcated the major sources of metals from tannery, paint, municipal sewage, textiles, and agricultural activities.

Characterization of selected biological, chemical, and physical conditions at fixed sites in the Upper Colorado River basin, Colorado, 1995-98

USGS Publications Warehouse

Deacon, Jeffrey R.; Mize, Scott V.; Spahr, Norman E.

1999-01-01

Biological community samples were collected at 15 sites in the Upper Colorado River Basin (UCOL) in Colorado as part of the National Water-Quality Assessment (NAWQA) Program. Sites sampled in two physiographic provinces, the Southern Rocky Mountains and the Colorado Plateau, represented agriculture, mining, urban and recreation, and mixed land uses and background conditions. Nine measures of water quality, which include information on nutrients, specific conductance (a surrogate for salinity), trace elements in streambed sediment, pesticides in fish tissue, fish communities, and macroinvertebrate richness and composition and stream habitat were used for comparisons among sites within the two physiographic provinces. Sampling sites from three other NAWQA study units?the Rio Grande Valley, the South Platte River Basin, and the Upper Snake River Basin study units?were categorized on the basis of land use and stream size in order to develop a larger data set for comparison to sites in the UCOL. Three categories of land use?forested (includes mining, urban and recreation, and background), agriculture, and mixed?were used for comparison to the UCOL fixed sites. Results indicated that all sites other than the Colorado River below Baker Gulch (a background site) showed some water-quality characteristics to be significantly affected. Results indicated that the concentrations of cadmium and zinc in streambed sediment at mining land-use sites in the Southern Rocky Mountains physiographic province generally were orders of magnitude higher than streambed-sediment concentrations at the background site. Streambed-sediment concentrations at mining land-use sites in the UCOL were greater than the 75th percentile of concentrations from sites in the three other NAWQA study units. Fish communities and habitat conditions were degraded at mining land-use sites compared to the background site. Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness and the percentage of EPT were lower at mining land-use sites than at the background site and were less than the 50th percentile of those for sites from the three other NAWQA study units. Nutrient concentrations at urban and recreation sites in the Southern Rocky Mountain physiographic province generally were greater than concentrations at the background site and generally were between the 25th and 90th percentile of concentrations for sites from the three other NAWQA study units. Habitat conditions and fish communities at urban and recreation sites were slightly degraded compared to the background site. EPT richness and the percentage of EPT were lower at urban and recreation sites than at the background site and were between the 25th and 75th percentile of those for sites from the three other NAWQA study units. The percentage of Chironomidae, which may be indicative of pollutant-tolerant organisms, was higher at urban and recreation sites than at the background site. Mixed land-use sites in the Southern Rocky Mountains physiographic province had similar nutrient concentrations and similar cadmium and zinc streambed-sediment concentrations. Fish-community degradation index values were very different among the three mixed land-use sites in the Southern Rocky Mountains physiographic province. Larger percentages of omnivores and anomalies such as lesions and deformities at two mixed land-use sites resulted in higher degradation values of the fish community. Agriculture land-use sites had higher concentrations of nutrients and selenium than the background site in the Colorado Plateau physiographic province. Concentrations of p,p'-DDE in fish tissue at agriculture sites were higher than the 75th percentile of concentrations for sites from the three other NAWQA study units. Fish communities had degradation values near the 75th percentile for agriculture sites. The percentage of EPT was low at agriculture sites when compared to the background site. Two mixed land-use sites in the Colorado Plateau physiographi

Final Project Report: Release of aged contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jon Chorover, University of Arizona; Peggy O'€™Day, University of California, Merced; Karl Mueller, Penn State University

2012-10-01

Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake. In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided detailed characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, PCO2, and reaction time; (ii) improved molecular-scale understanding of howmore » sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions.« less

Applying multivariate analysis as decision tool for evaluating sediment-specific remediation strategies.

PubMed

Pedersen, Kristine B; Lejon, Tore; Jensen, Pernille E; Ottosen, Lisbeth M

2016-05-01

Multivariate methodology was employed for finding optimum remediation conditions for electrodialytic remediation of harbour sediment from an Arctic location in Norway. The parts of the experimental domain in which both sediment- and technology-specific remediation objectives were met were identified. Objectives targeted were removal of the sediment-specific pollutants Cu and Pb, while minimising the effect on the sediment matrix by limiting the removal of naturally occurring metals while maintaining low energy consumption. Two different cell designs for electrochemical remediation were tested and final concentrations of Cu and Pb were below background levels in large parts of the experimental domain when operating at low current densities (<0.12 mA/cm(2)). However, energy consumption, remediation times and the effect on naturally occurring metals were different for the 2- and 3-compartment cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

Initial Results on the Extraterrestrial Component of New Sediment Cores Containing Deposits of the Eltanin Impact Event

NASA Technical Reports Server (NTRS)

Kyte, Frank T.; Gersonde, Rainer

2003-01-01

Background The impact of the Eltanin asteroid into the Bellingshausen Sea (2.15 Ma) is the only known impact in a deep-ocean (approx. 5 km) basin. In 1995, Polarstern expedition ANT XII/4 made the first geological survey of the suspected impact region. Three sediment cores sampled around the San Martin seamounts (approx. 57.5 S, 91 W) contained well-preserved impact deposits. Sediments of Eocene age and younger were ripped up and redeposited by the impact. The depositional sequence produced by the impact has three units: a chaotic assemblage of sediment fragments up to 50 cm, followed by laminated sands deposited as a turbulent flow, and finally silts and clays that accumulated from dispersed sediments in the water column. The meteoritic impact ejecta, which is composed of shock-melted asteroidal materials and unmelted meteorites, settled through the water column and concentrated near the top of the laminated sands.

Longitudinal variation in suspended sediment and turbidity of two undisturbed streams in northwestern California in relation to the monitoring of water quality above and below a land disturbance

Treesearch

Steve G. Markman

1990-01-01

Abstract - In-stream water quality regulations of California state that silvicultural disturbances must not increase turbidity levels more than 20 percent above naturally occurring background levels. These regulations fail to take into account the natural variation of turbidity and suspended sediment concentration along a short stretch of an undisturbed stream. At...

Relationships of sedimentation and benthic macroinvertebrate assemblages in headwater streams using systematic longitudinal sampling at the reach scale.

PubMed

Longing, S D; Voshell, J R; Dolloff, C A; Roghair, C N

2010-02-01

Investigating relationships of benthic invertebrates and sedimentation is challenging because fine sediments act as both natural habitat and potential pollutant at excessive levels. Determining benthic invertebrate sensitivity to sedimentation in forested headwater streams comprised of extreme spatial heterogeneity is even more challenging, especially when associated with a background of historical and intense watershed disturbances that contributed unknown amounts of fine sediments to stream channels. This scenario exists in the Chattahoochee National Forest where such historical timber harvests and contemporary land-uses associated with recreation have potentially affected the biological integrity of headwater streams. In this study, we investigated relationships of sedimentation and the macroinvertebrate assemblages among 14 headwater streams in the forest by assigning 30, 100-m reaches to low, medium, or high sedimentation categories. Only one of 17 assemblage metrics (percent clingers) varied significantly across these categories. This finding has important implications for biological assessments by showing streams impaired physically by sedimentation may not be impaired biologically, at least using traditional approaches. A subsequent multivariate cluster analysis and indicator species analysis were used to further investigate biological patterns independent of sedimentation categories. Evaluating the distribution of sedimentation categories among biological reach clusters showed both within-stream variability in reach-scale sedimentation and sedimentation categories generally variable within clusters, reflecting the overall physical heterogeneity of these headwater environments. Furthermore, relationships of individual sedimentation variables and metrics across the biological cluster groups were weak, suggesting these measures of sedimentation are poor predictors of macroinvertebrate assemblage structure when using a systematic longitudinal sampling design. Further investigations of invertebrate sensitivity to sedimentation may benefit from assessments of sedimentation impacts at different spatial scales, determining compromised physical habitat integrity of specific taxa and developing alternative streambed measures for quantifying sedimentation.

Tropical Cyclone-Driven Sediment Dynamics Over the Australian North West Shelf

NASA Astrophysics Data System (ADS)

Dufois, François; Lowe, Ryan J.; Branson, Paul; Fearns, Peter

2017-12-01

Owing to their strong forcing at the air-sea interface, tropical cyclones are a major driver of hydrodynamics and sediment dynamics of continental shelves, strongly impacting marine habitats and offshore industries. Despite the North West Shelf of Australia being one of the most frequently impacted tropical cyclone regions worldwide, there is limited knowledge of how tropical cyclones influence the sediment dynamics of this shelf region, including the significance of these episodic extreme events to the normal background conditions that occur. Using an extensive 2 year data set of the in situ sediment dynamics and 14 yearlong calibrated satellite ocean-color data set, we demonstrate that alongshore propagating cyclones are responsible for simultaneously generating both strong wave-induced sediment resuspension events and significant southwestward subtidal currents. Over the 2 year study period, two particular cyclones (Iggy and Narelle) dominated the sediment fluxes resulting in a residual southwestward sediment transport over the southern part of the shelf. By analyzing results from a long-term (37 year) wind and wave hindcast, our results suggest that at least 16 tropical cyclones had a strong potential to contribute to that southwestward sediment pathway in a similar way to Iggy and Narelle.

Trace-metal and organic constituent concentrations in bed sediment at Big Base and Little Base Lakes, Little Rock Air Force Base, Arkansas—Comparisons to sediment-quality guidelines and indications for timing of exposure

USGS Publications Warehouse

Justus, B.G.; Hays, Phillip D.; Hart, Rheannon M.

2015-09-16

Regarding highest concentrations and associated timing of exposure, trace metals analyzed in the sediment core seem to indicate three fairly distinct exposure patterns. For 11 trace metals that had the highest concentration measured in the shallowest and most recently deposited sediment, the most likely explanation is recent exposure by anthropogenic activities. Most of the 11 trace metals with highest concentrations in shallow sediment are relatively innocuous; however, arsenic, copper, selenium, and zinc are among the U.S. Environmental Protection Agency’s 126 priority pollutants. For three trace metals (cadmium, lead, and mercury), for which concentrations were highest in sediments that were 16–20 centimeters down the core, it is likely that a source associated with those contaminants during the period when those sediments were deposited, was reduced or eliminated. The eight remaining trace metals, for which concentrations were highest in sediments that were just below the prereservoir surface, likely had sources that were eliminated soon after lake construction or occurred at relatively high background concentrations in soils in the area around Little Rock Air Force Base.

Use of spatial statistics and isotopic tracers to measure the influence of arsenical pesticide use on stream sediment chemistry in New England, USA

USGS Publications Warehouse

Robinson, G.R.; Ayuso, R.A.

2004-01-01

Arsenical pesticides and herbicides, principally Pb arsenate, Ca arsenate, and Na arsenate with lesser use of other metal-As pesticides, were widely applied on apple, blueberry, and potato crops in New England during the first half of the twentieth century. Agricultural census data for this time period is used to define an agricultural index that identifies areas that are inferred to have used arsenical pesticides extensively. Factor analysis on metal concentrations in 1597 stream sediment samples collected throughout New England, grouped by agricultural-index categories, indicate a positive association of areas with stream sediment sample populations that contain higher As and Pb concentrations than samples from the region as a whole with sample site settings having high agricultural-index values. Population statistics for As and Pb concentrations and factor scores for an As-Pb factor all increase systematically and significantly with increasing agricultural-index intensity in the region, as tested by Kruskal-Wallis analysis. Lead isotope compositions for 16 stream sediments from a range of agricultural-index settings generally overlap the observed variation in rock sulfides and their weathering products; however, sediments collected from high agricultural-index settings have slightly more radiogenic Pb compositions, consistent with an industrial Pb contribution to these samples. Although weathering products from rocks are likely to be the dominant source of As and metals to most of the stream sediment samples collected in the region, the widespread use of arsenical pesticides and herbicides in New England during the early 1900-1960s appears to be a significant anthropogenic source of As and metals to many sediments in agricultural areas in the region and has raised background levels of As in some regions. Elevated concentrations of As in stream sediments are of concern for two reasons. Stream sediments with elevated As concentrations delineate areas with elevated background concentrations of As from both natural rock and anthropogenic sources that may contribute As to groundwater systems used for drinking water supplies. Conversion of agricultural land contaminated with arsenical pesticide residues to residential development may increase the likelihood that humans will be exposed to As. In addition, many stream sediment sites have As concentrations that exceed sediment quality guidelines established for freshwater ecosystems. Thirteen percent of the New England sediment sample sites exceed 9.79 mg/kg As, the threshold effects concentration (TEC), below which harmful effects are unlikely to be observed. Arsenic concentrations exceed 33 mg/kg, the probable effects concentration (PEC), above which harmful effects on sediment-dwelling organisms are expected to occur frequently, at 1.25% of the sediment sample sites. The sample sites that exceed the PEC value occur predominately in agricultural areas that used arsenical pesticides.

Environmental assessment of aromatic hydrocarbons-contaminated sediments of the Mexican Salina Cuz Bay.

PubMed

González-Macías, C; Schifter, I; Lluch-Cota, D B; Méndez-Rodríguez, L; Hernández-Vázquez, S

2007-10-01

Concentrations of total aromatic hydrocarbons and extractable organic matter in the water column and sediment were determined in samples collected in the course of the last 20 years from the Salina Cruz Harbor, México, to assess the degree of organic contamination. In sediments, organic compounds accumulate in shallow areas mostly associated with extractable organic matter and fine fractions. Calculated geocumulation index and enrichment factors suggest that contamination could be derived from anthropogenic activities attributed to harbor and ship scrapping activities, as well as transboundary source. Concentration of total aromatic hydrocarbons (as chrysene equivalents) ranged from 0.01 to 534 microg l(-1) in water, and from 0.10 to 2,160 microg g(-1) in sediments. Total aromatic concentration of 5 microg g(-1) is proposed as background concentration.

Conceptual Basis for a Hazardous Waste Component of the Army Environmental Data Management System (AEDMS)

DTIC Science & Technology

1988-09-01

environmental branch of their hazardous waste activities. Trend Analysis Before EPA had finished promulgating regulations designed to address all aspects of... Cotonal do"yd B 100 (454) Aminhinm cait-inail. 1) 5i,0)) (2.2170) CJpFrc Meetet B 100( 45>4) Ai-ncniir 0liic1Ŕ. Li 5.0iA1 (2.2 70) C.Ac acatoersenita 8 1

Capillary Discharge Thruster Experiments and Modeling (Briefing Charts)

DTIC Science & Technology

2016-06-01

Martin1 ERC INC.1, IN-SPACE PROPULSION BRANCH, AIR FORCE RESEARCH LABORATORY EDWARDS AIR FORCE BASE, CA USA Electric propulsion systems June 2016... PROPULSION MODELS & EXPERIMENTS Spacecraft Propulsion Relevant Plasma: From hall thrusters to plumes and fluxes on components Complex reaction physics i.e... Propulsion Plumes FRC Chamber Environment R.S. MARTIN (ERC INC.) DISTRIBUTION A: APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED; PA# 16279 3 / 30 ELECTRIC

Modeling of Diffusion Based Correlations Between Heart Rate Modulations and Respiration Pattern

DTIC Science & Technology

2001-10-25

1 of 4 MODELING OF DIFFUSION BASED CORRELATIONS BETWEEN HEART RATE MODULATIONS AND RESPIRATION PATTERN R.Langer,(1) Y.Smorzik,(2) S.Akselrod,(1...generations of the bronchial tree. The second stage describes the oxygen diffusion process from the pulmonary gas in the alveoli into the pulmonary...patterns (FRC, TV, rate). Keywords – Modeling, Diffusion , Heart Rate fluctuations I. INTRODUCTION Under a whole-body management perception, the

Realization of FRC interior and exterior furniture

NASA Astrophysics Data System (ADS)

Šonka, Š.; Frantová, M.; Štemberk, P.; Havrda, J.; Janouch, P.

2017-09-01

This article deals with the implementation of fibre reinforced concrete for interior and exterior furniture. The use of fibre reinforced concrete for non-traditional and small structures brings some specifics in design and realization. These are, in particular, the design of a suitable mixture, the choice of the shape of the structure in relation to the technological possibilities of realization, the static effects and finally the actual production of the element.

Jackson Mills and Mine Falls Dams, Nashua, New Hampshire. Reconnaissance Report, Hydroelectric Feasibility. Volume 2. Mine Falls Dam.

DTIC Science & Technology

1980-01-01

producers under a state law of 1978. Until the regulations under PURPA Title II (the National Energy Act of 1978) are promulgated and the PUC reviews this...hour (rWi); end it is FURTr.R ORDERMD, that the Corumission will re-examine th4 PURPA issues in this proceedirg upon the issuance of rules by the F-RC

Burrow characteristics of the mud shrimp Austinogebia edulis, an ecological engineer causing sediment modification of a tidal flat

PubMed Central

Das, Shagnika; Tseng, Li-Chun; Wang, Lan

2017-01-01

The mud shrimp Austinogebia edulis, being abundant in the intertidal zone of western Taiwan, constructs deep burrows (>1 m). This study highlights the potential of mud shrimps to modify sediment characteristics of the tidal flat by its burrowing behavior. We studied the structure of the burrow wall, compared the difference in the sediment composition of the burrow and the background sediment, and compared the organic content inside the burrow wall. This study was carried out from September 2015 to November 2016 in three areas of the western coast of Taiwan, namely Shengang, Hanbow, and Wangong. The present study found significant differences between burrow wall and the burrow lumen. The diameter of the burrow wall was double as wide as the inner burrow lumen at the opening and gradually increased to 10 times of the burrow lumen at 30 cm depth. The burrow wall of A. edulis showed low permeability and increased the sheer strength. Statistically, a significant difference was noticed in the comparison between the sediment composition of the burrow wall and the background (p < 0.05, Student’s t-test). An accumulation of 3.63 for fine sand (t = -5.22, p < 0.001, fine sand) and 9 for clay (t = -25.01, p < 0.001, clay) was found in the upper burrow wall of A. edulis. This indicated that they somehow chose finer particles to build burrows. This will gradually change the sediment distribution—vertically and horizontally. The burrow wall consisted of a 24 times higher organic matter content than one individual of mud shrimp. The burrow may provide organic material as a potential food source. The mud shrimp thus transforms the sediment characteristics as an ecological engineer, which is expected to have a significant ecological impact on the ecosystem. PMID:29236717

Effect of short-term water storage on the elastic properties of some dental restorative materials--A resonant ultrasound spectroscopy study.

PubMed

Pastila, Pirjo; Lassila, Lippo V J; Jokinen, Mikko; Vuorinen, Jyrki; Vallittu, Pekka K; Mäntylä, Tapio

2007-07-01

This study was aimed to determine if short-term water storage would change elastic properties of dental composite materials. Particulate filler composite resin and continuous unidirectional E-glass FRC materials were photopolymerized and additionally post-polymerized by heat for testing elastic properties with the Resonance Ultrasound Spectroscopy method as a function of time in water storage. The test specimens were stored in 37 degrees C water for up to 30 days. About 1% weight increase due to water sorption was observed in both materials with both polymerization methods. Water sorption did not change the resonance frequencies towards lower values, indicating no significant decrease in elastic properties in these materials. Because of high damping of the polymer composite materials leading to wide resonance peaks and low number of the recorded peaks, accurate determination of the elastic properties was not possible. Results suggest that the most likely explanation for the previously observed decrease in bending stiffness of FRC materials is the decreased yield limit of the hydrated polymer matrix. It is important to recognize that water sorption has the effect on mechanical properties of dental composite materials by changing the yield limit of the matrix rather than by changing the elastic properties of the material.

Langmuir probe diagnostic suite in the C-2 field-reversed configuration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roche, T., E-mail: troche@trialphaenergy.com; Armstrong, S.; Knapp, K.

2014-11-15

Several in situ probes have been designed and implemented into the diagnostic array of the C-2 field-reversed configuration (FRC) at Tri Alpha Energy [M. Tuszewski et al. (the TAE Team), Phys. Rev. Lett. 108, 255008 (2012)]. The probes are all variations on the traditional Langmuir probe. They include linear arrays of triple probes, linear arrays of single-tipped swept probes, a multi-faced Gundestrup probe, and an ion-sensitive probe. The probes vary from 5 to 7 mm diameter in size to minimize plasma perturbations. They also have boron nitride outer casings that prevent unwanted electrical breakdown and reduce the introduction of impurities.more » The probes are mounted on motorized linear-actuators allowing for programmatic scans of the various plasma parameters over the course of several shots. Each probe has a custom set of electronics that allows for measurement of the desired signals. High frequency ( > 5MHz) analog optical-isolators ensure that plasma parameters can be measured at sub-microsecond time scales while providing electrical isolation between machine and data acquisition systems. With these probes time-resolved plasma parameters (temperature, density, spatial potential, flow, and electric field) can be directly/locally measured in the FRC jet and edge/scrape-off layer.« less

Auto-magnetizing liners for magnetized inertial fusion

DOE PAGES

Slutz, S. A.; Jennings, C. A.; Awe, T. J.; ...

2017-01-20

Here, the MagLIF (Magnetized Liner Inertial Fusion) concept has demonstrated fusion-relevant plasma conditions on the Z accelerator using external field coils to magnetize the fuel before compression. We present a novel concept (AutoMag), which uses a composite liner with helical conduction paths separated by insulating material to provide fuel magnetization from the early part of the drive current, which by design rises slowly enough to avoid electrical breakdown of the insulators. Once the magnetization field is established, the drive current rises more quickly, which causes the insulators to break down allowing the drive current to follow an axial path andmore » implode the liner in the conventional z-pinch manner. There are two important advantages to AutoMag over external field coils for the operation of MagLIF. Low inductance magnetically insulated power feeds can be used to increase the drive current, and AutoMag does not interfere with diagnostic access. Also, AutoMag enables a pathway to energy applications for MagLIF, since expensive field coils will not be damaged each shot. Finally, it should be possible to generate Field Reversed Configurations (FRC) by using both external field coils and AutoMag in opposite polarities. This would provide a means to studying FRC liner implosions on the 100 ns time scale.« less

The impact of surfactant replacement therapy on cerebral and systemic circulation and lung function.

PubMed

Schipper, J A; Mohammad, G I; van Straaten, H L; Koppe, J G

1997-03-01

The influence of surfactant administration on cerebral and systemic circulation and on lung function was evaluated in 12 premature mechanically ventilated infants (mean birth weight 1,560 +/- 770 g, mean gestational age 30.0 +/- 3.2 weeks) with respiratory distress syndrome (RDS) receiving surfactant replacement therapy. We measured mean cerebral blood flow velocity (MCBFV), heart rate (HR), mean arterial pressure (MAP), static compliance (Crs), resistance of respiratory system (Rrs), functional residual capacity (FRC) and fraction of inspired oxygen (FiO2). In addition to a very low compliance and a moderately elevated resistance of the respiratory system a significant drop in MAP, HR, MCBFV and FiO2 was noticed after surfactant administration. After 30 min HR, MAP and MCBFV values returned to baseline levels. We postulate that the drop in MCBFV, MAP, HR and FiO2 with a minor, though not significant improvement of the FRC can most likely be explained by a "relative" hypovolaemia in other organs and parts of the body due to expansion of the lung vascular bed. Compensation for the redistribution of circulatory volume occurred within several minutes. Blood pressure control and treatment of hypovolaemia is mandatory before surfactant is administered. In RDS patients there is a significant drop of MAP, HR, MCBFV and FiO2 after bolus surfactant administration.

Laboratory studies of magnetized collisionless flows and shocks using accelerated plasmoids

NASA Astrophysics Data System (ADS)

Weber, T. E.; Smith, R. J.; Hsu, S. C.

2015-11-01

Magnetized collisionless shocks are thought to play a dominant role in the overall partition of energy throughout the universe, but have historically proven difficult to create in the laboratory. The Magnetized Shock Experiment (MSX) at LANL creates conditions similar to those found in both space and astrophysical shocks by accelerating hot (100s of eV during translation) dense (1022 - 1023 m-3) Field Reversed Configuration (FRC) plasmoids to high velocities (100s of km/s); resulting in β ~ 1, collisionless plasma flows with sonic and Alfvén Mach numbers of ~10. The FRC subsequently impacts a static target such as a strong parallel or anti-parallel (reconnection-wise) magnetic mirror, a solid obstacle, or neutral gas cloud to create shocks with characteristic length and time scales that are both large enough to observe yet small enough to fit within the experiment. This enables study of the complex interplay of kinetic and fluid processes that mediate cosmic shocks and can generate non-thermal distributions, produce density and magnetic field enhancements much greater than predicted by fluid theory, and accelerate particles. An overview of the experimental capabilities of MSX will be presented, including diagnostics, selected recent results, and future directions. Supported by the DOE Office of Fusion Energy Sciences under contract DE-AC52-06NA25369.

Dual wavelength imaging of a scrape-off layer in an advanced beam-driven field-reversed configuration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osin, D.; Schindler, T., E-mail: dosin@trialphaenergy.com

2016-11-15

A dual wavelength imaging system has been developed and installed on C-2U to capture 2D images of a He jet in the Scrape-Off Layer (SOL) of an advanced beam-driven Field-Reversed Configuration (FRC) plasma. The system was designed to optically split two identical images and pass them through 1 nm FWHM filters. Dual wavelength images are focused adjacent on a large format CCD chip and recorded simultaneously with a time resolution down to 10 μs using a gated micro-channel plate. The relatively compact optical system images a 10 cm plasma region with a spatial resolution of 0.2 cm and can bemore » used in a harsh environment with high electro-magnetic noise and high magnetic field. The dual wavelength imaging system provides 2D images of either electron density or temperature by observing spectral line pairs emitted by He jet atoms in the SOL. A large field of view, combined with good space and time resolution of the imaging system, allows visualization of macro-flows in the SOL. First 2D images of the electron density and temperature observed in the SOL of the C-2U FRC are presented.« less

Factors Affecting Lung Function: A Review of the Literature.

PubMed

Talaminos Barroso, Alejandro; Márquez Martín, Eduardo; Roa Romero, Laura María; Ortega Ruiz, Francisco

2018-06-01

Lung function reference values are traditionally based on anthropometric factors, such as weight, height, sex, and age. FVC and FEV 1 decline with age, while volumes and capacities, such as RV and FRC, increase. TLC, VC, RV, FVC and FEV 1 are affected by height, since they are proportional to body size. This means that a tall individual will experience greater decrease in lung volumes as they get older. Some variables, such as FRC and ERV, decline exponentially with an increase in weight, to the extent that tidal volume in morbidly obese patients can be close to that of RV. Men have longer airways than women, causing greater specific resistance in the respiratory tract. The increased work of breathing to increase ventilation among women means that their consumption of oxygen is higher than men under similar conditions of physical intensity. Lung volumes are higher when the subject is standing than in other positions. DLCO is significantly higher in supine positions than in sitting or standing positions, but the difference between sitting and standing positions is not significant. Anthropometric characteristics are insufficient to explain differences in lung function between different ethnic groups, underlining the importance of considering other factors in addition to the conventional anthropometric measurements. Copyright © 2018 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.

Development of 1D Liner Compression Code for IDL

NASA Astrophysics Data System (ADS)

Shimazu, Akihisa; Slough, John; Pancotti, Anthony

2015-11-01

A 1D liner compression code is developed to model liner implosion dynamics in the Inductively Driven Liner Experiment (IDL) where FRC plasmoid is compressed via inductively-driven metal liners. The driver circuit, magnetic field, joule heating, and liner dynamics calculations are performed at each time step in sequence to couple these effects in the code. To obtain more realistic magnetic field results for a given drive coil geometry, 2D and 3D effects are incorporated into the 1D field calculation through use of correction factor table lookup approach. Commercial low-frequency electromagnetic fields solver, ANSYS Maxwell 3D, is used to solve the magnetic field profile for static liner condition at various liner radius in order to derive correction factors for the 1D field calculation in the code. The liner dynamics results from the code is verified to be in good agreement with the results from commercial explicit dynamics solver, ANSYS Explicit Dynamics, and previous liner experiment. The developed code is used to optimize the capacitor bank and driver coil design for better energy transfer and coupling. FRC gain calculations are also performed using the liner compression data from the code for the conceptual design of the reactor sized system for fusion energy gains.

Anthropogenic platinum and palladium in the sediments of Boston Harbor

USGS Publications Warehouse

Tuit, C.B.; Ravizza, G.E.; Bothner, Michael H.

2000-01-01

Anthropogenic activity has increased recent sediment concentrations of Pt and Pd in Boston Harbor by approximately 5 times background concentrations. Surface sediments and downcore profiles were investigated to evaluate Pt and Pd accumulation and behavior in urban coastal sediments. There is no clear correlation between temporal changes in Pt and Pd consumption and sediment concentration. However, Pt/Pb and Pd/Pb ratios suggest that Pt and Pd flux into the Harbor may not be decreasing with cessation of sludge input as rapidly as other metals. This is supported by the large discrepancy between fluxes associated with sludge and effluent release and those calculated from surface sediment concentrations. This evidence supports catalytic converters as a major source of Pd and Pt to Boston Harbor but cannot preclude other sources. Pd does not exhibit signs of post-burial remobilization below the mixed layer in the sediment cores, although near-surface variability in Pd concentrations may indicate a labile Pd component. Pt displays an inverse correlation with Mn above the oxic/suboxic transition, similar to behavior seen in pristine sediments where Pt is thought to be chemically mobile. This study does not support the use of Pd and Pt as tracers of recent contaminated sedimentation. However, the possibility of a labile Pt and Pd in these sediments highlights the need for further study of the biological uptake of these metals.

Sedimentation and Occurrence and Trends of Selected Chemical Constituents in Bottom Sediment, Empire Lake, Cherokee County, Kansas, 1905-2005

USGS Publications Warehouse

Juracek, Kyle E.

2006-01-01

For about 100 years (1850-1950), the Tri-State Mining District in parts of southeast Kansas, southwest Missouri, and northeast Oklahoma was one of the primary sources of lead and zinc ore in the world. The mining activity in the Tri-State District has resulted in substantial historical and ongoing input of cadmium, lead, and zinc to the environment including Empire Lake in Cherokee County, southeast Kansas. The environmental contamination caused by the decades of mining activity resulted in southeast Cherokee County being listed on the U.S. Environmental Protection Agency's National Priority List as a superfund hazardous waste site in 1983. To provide some of the information needed to support efforts to restore the ecological health of Empire Lake, a 2-year study was begun by the U.S. Geological Survey in cooperation with the U.S. Fish and Wildlife Service and the Kansas Department of Health and Environment. A combination of sediment-thickness mapping and bottom-sediment coring was used to investigate sediment deposition and the occurrence of cadmium, lead, zinc, and other selected constituents in the bottom sediment of Empire Lake. The total estimated volume and mass of bottom sediment in Empire Lake were 44 million cubic feet and 2,400 million pounds, respectively. Most of the bottom sediment was located in the main body and the Shoal Creek arm of the reservoir. Minimal sedimentation was evident in the Spring River arm of the reservoir. The total mass of cadmium, lead, and zinc in the bottom sediment of Empire Lake was estimated to be 78,000 pounds, 650,000 pounds, and 12 million pounds, respectively. In the bottom sediment of Empire Lake, cadmium concentrations ranged from 7.3 to 76 mg/kg (milligrams per kilogram) with an overall median concentration of 29 mg/kg. Compared to an estimated background concentration of 0.4 mg/kg, the historical mining activity increased the median cadmium concentration by about 7,200 percent. Lead concentrations ranged from 100 to 950 mg/kg with an overall median concentration of 270 mg/kg. Compared to an estimated background concentration of 33 mg/kg, the median lead concentration was increased by about 720 percent as a result of mining activities. The range in zinc concentrations was 1,300 to 13,000 mg/kg with an overall median concentration of 4,900 mg/kg. Compared to an estimated background concentration of 92 mg/kg, the median zinc concentration was increased by about 5,200 percent. Within Empire Lake, the largest sediment concentrations of cadmium, lead, and zinc were measured in the main body of the reservoir. Within the Spring River arm of the reservoir, increased concentrations in the downstream direction likely were the result of tributary inflow from Short Creek, which drains an area that has been substantially affected by historical lead and zinc mining. Compared to nonenforceable sediment-quality guidelines, all Empire Lake sediment samples (representing 21 coring sites) had cadmium concentrations that exceeded the probable-effects guideline (4.98 mg/kg), which represents the concentration above which toxic biological effects usually or frequently occur. With one exception, cadmium concentrations exceeded the probable-effects guideline by about 180 to about 1,400 percent. With one exception, all sediment samples had lead concentrations that exceeded the probable-effects guideline (128 mg/kg) by about 10 to about 640 percent. All sediment samples had zinc concentrations that exceeded the probable-effects guideline (459 mg/kg) by about 180 to about 2,700 percent. Overall, cadmium, lead, and zinc concentrations in the bottom sediment of Empire Lake have decreased over time following the end of lead and zinc mining in the area. However, the concentrations in the most recently deposited bottom sediment (determined for 4 of 21 coring sites) still exceeded the probable-effects guideline by about 440 to 640 percent for cadmium, about 40 to 80 percent for lead, and about 580

Adjustment of geochemical background by robust multivariate statistics

USGS Publications Warehouse

Zhou, D.

1985-01-01

Conventional analyses of exploration geochemical data assume that the background is a constant or slowly changing value, equivalent to a plane or a smoothly curved surface. However, it is better to regard the geochemical background as a rugged surface, varying with changes in geology and environment. This rugged surface can be estimated from observed geological, geochemical and environmental properties by using multivariate statistics. A method of background adjustment was developed and applied to groundwater and stream sediment reconnaissance data collected from the Hot Springs Quadrangle, South Dakota, as part of the National Uranium Resource Evaluation (NURE) program. Source-rock lithology appears to be a dominant factor controlling the chemical composition of groundwater or stream sediments. The most efficacious adjustment procedure is to regress uranium concentration on selected geochemical and environmental variables for each lithologic unit, and then to delineate anomalies by a common threshold set as a multiple of the standard deviation of the combined residuals. Robust versions of regression and RQ-mode principal components analysis techniques were used rather than ordinary techniques to guard against distortion caused by outliers Anomalies delineated by this background adjustment procedure correspond with uranium prospects much better than do anomalies delineated by conventional procedures. The procedure should be applicable to geochemical exploration at different scales for other metals. ?? 1985.

LLRV in flight and landing on ramp

NASA Technical Reports Server (NTRS)

1960-01-01

This 26-second video clip shows the LLRV flying and landing. The LLRV's, humorously referred to as 'flying bedsteads,' were created by a predecessor of the NASA Dryden Flight Research Center and Bell Aerosystems Company, Niagra Falls, New York, to study and analyze piloting techniques needed to fly and land the tiny Apollo Lunar Module in the Moon's airless environment. (Dryden was known simply as the NASA Flight Research Center from 1959 to 1976.) Success of the LLRV's led to the building of three Lunar Landing Training Vehicles (LLTV) used by Apollo astronauts at the Manned Spacecraft Center, Houston, Texas, predecessor of the NASA Johnson Space Center. Apollo 11 astronaut, Neil Armstrong -- first human to step onto the Moon's surface -- said the mission would not have been successful without the type of simulation that resulted from the LLRV's. When Apollo planning was underway in 1960, NASA was looking for a simulator to profile the descent to the Moon's surface. Three concepts developed: an electronic simulator, a tethered device, and the ambitious Flight Research Center (FRC) contribution, a free-flying vehicle. All three became serious projects, but eventually the FRC's LLRV became the most significant one. Hubert Drake is credited with originating the idea, while Donald Bellman and Gene Matranga were senior engineers on the project, with Bellman the project manager. After conceptual planning and meetings with engineers from Bell Aerosystems, a company with experience in vertical takeoff and landing (VTOL) aircraft, NASA issued Bell a $50,000 study contract in December 1961. Bell had independently conceived a similar, free-flying simulator, and out of this study came the headquarters' endorsement of the LLRV concept, resulting in a $3.6 million production contract awarded to Bell February 1, 1963, for delivery of the first of two vehicles for flight studies at the FRC within 14 months. Built of aluminum alloy trusses and shaped like a giant four-legged bedstead, the vehicle was to simulate a lunar landing profile. To do this, the LLRV had a General Electric CF-700-2V turbofan engine mounted vertically in a gimbal, with 4200 pounds of thrust. The engine got the vehicle up to the test altitude and was then throttled back to support five-sixths of the vehicle's weight, simulating the reduced gravity of the Moon. Two hydrogen peroxide lift rockets with thrust that could be varied from 100 to 500 pounds handled the LLRV's rate of descent and horizontal movement. Sixteen smaller hydrogen peroxide rockets, mounted in pairs, gave the pilot control in pitch, yaw, and roll. As safety backups on the LLRV, six 500-pound rockets could take over the lift function and stabilize the craft for a moment if the main jet engine failed. The pilot had a zero-zero ejection seat that would then lift him away to safety. The two LLRV's were shipped from Bell to the FRC in April 1964, with program emphasis on vehicle No. 1. It was first readied for captured flight on a tilt-table affair. The scene then shifted to the old South Base area of Edwards. On the day of the first flight, October 30, 1964, research pilot Joe Walker flew it three times for a total of just under 60 seconds to a peak altitude of ten feet (three meters). Later flights were shared between Walker, another Center pilot named Don Mallick, the Army's Jack Kleuver, NASA Manned Spacecraft Center, Houston, Texas, pilots Joseph Algranti and H.E. 'Bud' Ream. NASA had accumulated enough data from the LLRV flight program at the FRC by mid-1966 to give Bell a contract to deliver three LLTVs at a cost of $2.5 million each. In December 1966 vehicle No. 1 was shipped to Houston, followed by No. 2 in January 1967, within weeks of its first flight. Modifications already made to No. 2 had given the pilot a three-axis side control stick and a more restrictive cockpit view, both features of the real Lunar Module that would later be flown by the astronauts down to the Moon's surface. When the LLRV's arrived at Houston, where research pilots would learn how to become LLTV instructor pilots, No. 2 had been flown just seven times while No. 1, the veteran, had a total of 198 flights. In December 1967, the first of the LLTV's joined the FRC's LLRV's to eventually make up the five-vehicle training and simulator fleet. Three of the five vehicles were later destroyed in crashes at Houston - LLRV No. 1 in May 1968 and two LLTV's, in December 1968 and January 1971. The two accidents in 1968, before the first lunar landing, did not deter Apollo program managers who enthusiastically relied on the vehicles for simulation and training. Donald 'Deke' Slayton, then NASA's astronaut chief, said there was no other way to simulate a Moon landing except by flying the LLTV. LLRV No. 2 was eventually returned to Dryden, where it is on display as a silent artifact of the Center's contribution to the Apollo program.

LLRV liftoff from ramp

NASA Technical Reports Server (NTRS)

1960-01-01

This 24-second video clip shows the LLRV pilot strapping in and flying the vehicle. The LLRV's, humorously referred to as 'flying bedsteads,' were created by a predecessor of the NASA Dryden Flight Research Center and Bell Aerosystems Company, Niagra Falls, New York, to study and analyze piloting techniques needed to fly and land the tiny Apollo Lunar Module in the Moon's airless environment. (Dryden was known simply as the NASA Flight Research Center from 1959 to 1976.) Success of the LLRV's led to the building of three Lunar Landing Training Vehicles (LLTV) used by Apollo astronauts at the Manned Spacecraft Center, Houston, Texas, predecessor of the NASA Johnson Space Center. Apollo 11 astronaut, Neil Armstrong -- first human to step onto the Moon's surface -- said the mission would not have been successful without the type of simulation that resulted from the LLRV's. When Apollo planning was underway in 1960, NASA was looking for a simulator to profile the descent to the Moon's surface. Three concepts developed: an electronic simulator, a tethered device, and the ambitious Flight Research Center (FRC) contribution, a free-flying vehicle. All three became serious projects, but eventually the FRC's LLRV became the most significant one. Hubert Drake is credited with originating the idea, while Donald Bellman and Gene Matranga were senior engineers on the project, with Bellman the project manager. After conceptual planning and meetings with engineers from Bell Aerosystems, a company with experience in vertical takeoff and landing (VTOL) aircraft, NASA issued Bell a $50,000 study contract in December 1961. Bell had independently conceived a similar, free-flying simulator, and out of this study came the headquarters' endorsement of the LLRV concept, resulting in a $3.6 million production contract awarded to Bell February 1, 1963, for delivery of the first of two vehicles for flight studies at the FRC within 14 months. Built of aluminum alloy trusses and shaped like a giant four-legged bedstead, the vehicle was to simulate a lunar landing profile. To do this, the LLRV had a General Electric CF-700-2V turbofan engine mounted vertically in a gimbal, with 4200 pounds of thrust. The engine got the vehicle up to the test altitude and was then throttled back to support five-sixths of the vehicle's weight, simulating the reduced gravity of the Moon. Two hydrogen peroxide lift rockets with thrust that could be varied from 100 to 500 pounds handled the LLRV's rate of descent and horizontal movement. Sixteen smaller hydrogen peroxide rockets, mounted in pairs, gave the pilot control in pitch, yaw, and roll. As safety backups on the LLRV, six 500-pound rockets could take over the lift function and stabilize the craft for a moment if the main jet engine failed. The pilot had a zero-zero ejection seat that would then lift him away to safety. The two LLRV's were shipped from Bell to the FRC in April 1964, with program emphasis on vehicle No. 1. It was first readied for captured flight on a tilt-table affair. The scene then shifted to the old South Base area of Edwards. On the day of the first flight, October 30, 1964, research pilot Joe Walker flew it three times for a total of just under 60 seconds to a peak altitude of ten feet (three meters). Later flights were shared between Walker, another Center pilot named Don Mallick, the Army's Jack Kleuver, NASA Manned Spacecraft Center, Houston, Texas, pilots Joseph Algranti and H.E. 'Bud' Ream. NASA had accumulated enough data from the LLRV flight program at the FRC by mid-1966 to give Bell a contract to deliver three LLTV's at a cost of $2.5 million each. In December 1966 vehicle No. 1 was shipped to Houston, followed by No. 2 in January 1967, within weeks of its first flight. Modifications already made to No. 2 had given the pilot a three-axis side control stick and a more restrictive cockpit view, both features of the real Lunar Module that would later be flown by the astronauts down to the Moon's surface. When the LLRV's arrived at Houston, where research pilots would learn how to become LLTV instructor pilots, No. 2 had been flown just seven times while No. 1, the veteran, had a total of 198 flights. In December 1967, the first of the LLTV's joined the FRC's LLRV's to eventually make up the five-vehicle training and simulator fleet. Three of the five vehicles were later destroyed in crashes at Houston - LLRV No. 1 in May 1968 and two LLTVs, in December 1968 and January 1971. The two accidents in 1968, before the first lunar landing, did not deter Apollo program managers who enthusiastically relied on the vehicles for simulation and training. Donald 'Deke' Slayton, then NASA's astronaut chief, said there was no other way to simulate a Moon landing except by flying the LLTV. LLRV No. 2 was eventually returned to Dryden, where it is on display as a silent artifact of the Center's contribution to the Apollo program.

Accumulation and distribution of heavy metals in sediments and fish in the Kola Peninsula lakes under airborne contamination

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dauvalter, V.A.; Kashulin, N.A.; Lukin, A.A.

1996-12-31

The copper-nickel smelter complexes of Kola Peninsula are powerful sources of atmospheric contamination by heavy metals (Ni, Cu, Co, Cd, etc.) and acidic oxides (SO{sub 2}) deposited in precipitation and caused negative effects on local freshwater ecosystems. The rise of background levels occurs over large areas in the region. The aim of the investigations is to assess effects of the air contamination on lake ecosystems at different distances (from 15 to 120 km) from one of the main heavy metal pollution sources of the Kola Peninsula - smelters of the Pechenganickel Company. Negative effects of air pollution by the smeltersmore » on the freshwater ecosystems were recorded. Lake sediments accumulate very intensively heavy metals. Heavy metal contamination factors calculated as the quotient of concentration from the uppermost (0-1 cm) sediment to the mean preindustrial background value (concentrations from 20-30 cm sediment layers) for the investigated region reach up 120 for Ni and 76 for Cu in the lakes within a distance of 40 km from the smelters. The lakes in this region have very high contamination degree according classification by Hakanson (1980). Concentrations of Ni in organs and tissues of all studied fishes (whitefish, pike, perch, arctic char, brown trout) were considerably higher in the investigated lakes than in remote unpolluted lakes. There is tight positive correlation between Ni concentrations in surficial sediment (0-1 cm) and fish kidney (r = +0.854), as well as between values of contamination degree and Ni content in fish (r = +0.871).« less

Early diagenesis in the Congo deep-sea fan sediments dominated by massive terrigenous deposits: Part I - Oxygen consumption and organic carbon mineralization using a micro-electrode approach

NASA Astrophysics Data System (ADS)

Pozzato, Lara; Cathalot, Cécile; Berrached, Chabha; Toussaint, Flora; Stetten, Elsa; Caprais, Jean-Claude; Pastor, Lucie; Olu, Karine; Rabouille, Christophe

2017-08-01

Organic matter (OM) transfer from the continent to the ocean occurs across margins which constitute a major area of OM recycling and burial. The lobe complex of the Congo deep-sea fan is connected to the river mouth by a canyon and alimented by recurrent turbidity currents, containing a large proportion of labile terrigenous OM and producing high sedimentation rates. These inputs support the development of ecosystems harboring rich assemblages of vesicomyid bivalves and bacterial mats, called Habitats. Here, we present O2 microprofiles and diffusive oxygen uptake rates (DOUs) obtained during the CONGOLOBE project at six sites of this active lobe complex by in situ and on-board methods based on micro-electrode profiling. The dataset is used to determine remineralization rates and study the biogeochemical dynamics of different ecosystems of the lobe area, in order to compare levee and background sediments to the Habitats developed on the flanks of the main turbiditic channel. Levee and background sediments are characterized by significantly higher DOUs than abyssal sediments at 5000 m meters depth (2-5 mmol O2 m-2 d-1versus 1.5-2.5 mmol O2 m-2 d-1) and the Habitats are hotspots of OM remineralization with DOU values ranging between 8 and 40 mmol O2 m-2 d-1. By comparing sites near the active channel to a site located 50 km away, we show that the lobe connection to the main turbiditic channel is vital to the dense benthic communities.

Long-term changes in sediment barium inventories associated with drilling-related discharges in the Santa Maria Basin, California, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, C.; Evans, J.; Hom, W.

1998-09-01

Nine-year (1986--1995) records of barium (Ba) concentrations in surficial, subsurface, and suspended sediments near offshore oil and gas platforms in the Santa Maria Basin, California, USA, were analyzed to evaluate temporal trends related to drilling activities. These trends provide important information on the long-term effects of drilling discharges on geochemical conditions. Drilling during the 1986 through 1989 (phase II) monitoring period resulted in significant changes in Ba concentrations in suspended particles and surficial sediments, whereas the relatively shorter 1993 through 1994 (phase III) drilling operations resulted in only minor increases in Ba concentrations in suspended sediments. Residual excess Ba wasmore » present in some sediments within 500 m of the platforms at concentrations up to an order of magnitude above background. These elevated levels probably were associated with cuttings particles deposited near the base of the platforms. Calculated excess Ba in sediments within 500 m of the platforms represented 6 to 11% of the total Ba discharged during the two drilling periods.« less

Contamination of port zone sediments by metals from Large Marine Ecosystems of Brazil.

PubMed

Buruaem, Lucas M; Hortellani, Marcos A; Sarkis, Jorge E; Costa-Lotufo, Leticia V; Abessa, Denis M S

2012-03-01

Sediment contamination by metals poses risks to coastal ecosystems and is considered to be problematic to dredging operations. In Brazil, there are differences in sedimentology along the Large Marine Ecosystems in relation to the metal distributions. We aimed to assess the extent of Al, Fe, Hg, Cd, Cr, Cu, Ni, Pb and Zn contamination in sediments from port zones in northeast (Mucuripe and Pecém) and southeast (Santos) Brazil through geochemical analyses and sediment quality ratings. The metal concentrations found in these port zones were higher than those observed in the continental shelf or the background values in both regions. In the northeast, metals were associated with carbonate, while in Santos, they were associated with mud. Geochemical analyses showed enrichments in Hg, Cd, Cu, Ni and Zn, and a simple application of international sediment quality guidelines failed to predict their impacts, whereas the use of site-specific values that were derived by geochemical and ecotoxicological approaches seemed to be more appropriate in the management of the dredged sediments. Copyright © 2012 Elsevier Ltd. All rights reserved.

Distribution and accumulation of mercury and copper in mangrove sediments in Shenzhen, the world's most rapid urbanized city.

PubMed

Li, Ruili; Xu, Hualin; Chai, Minwei; Qiu, Guo Yu

2016-02-01

To investigate the influence of mangrove forest on heavy metal accumulation and storage in intertidal sediments, core sediments from natural mangrove, restored mangrove, and adjacent mud flat spanning the intertidal zone along the south coastline of the most heavily urbanized Deep bay, Guangdong province, China were analyzed. The average concentrations of mercury (Hg) in surface sediments of natural mangrove and restored mangrove were 172 and 151 ng g(-1), whereas those of copper (Cu) were 75 and 50 μg g(-1), respectively. Compared to those from other typical mangrove wetlands of the world, the metal levels in Shenzhen were at median to high levels, which is consistent with the fact that Shenzhen is in high exploitation and its mangrove suffer intensive impact from human activities. Hg and Cu concentration profiles indicated a higher metal accumulation in surface layers of sediments, in agreement with enrichment of organic matter contents. Maximum concentration, enrichment factors, and excess (background-deducted) concentration inventories of metals (Hg and Cu) were substantially different between environments, decreasing from natural mangrove sediments to restored mangrove sediments to mud flat. Furthermore, metal inputs to Futian mangrove decreased in the order natural mangrove > restored mangrove > mud flat, indicating that mangrove facilitated the accumulation and storage of Hg and Cu in sediment layers.

Towards the assessment and management of contaminated dredged materials.

PubMed

Agius, Suzanne J; Porebski, Linda

2008-04-01

Environment Canada's Disposal at Sea Programme hosted the Contaminated Dredged Material Management Decisions Workshop in Montreal, Quebec, Canada, on 28-30 November 2006. The workshop brought together over 50 sediment assessment and management experts from academic, industrial, and regulatory backgrounds and charged them with drafting a potential framework to assess contaminated dredged materials and compare the risks of various disposal alternatives. This article summarizes the recommendations made during the workshop concerning the development of sediment assessment tools, the interpretation of these tools, and the essential attributes of a comparative risk assessment process. The major outcomes of the workshop include a strong recommendation to develop a national dredging or sediment management strategy, a potential decision-making framework for the assessment of dredged materials and comparative risk assessment of disposal options, and the expansion of minimum sediment characterization requirements for nonroutine disposal permit applications.

A Residual Chlorine Removal Method to Allow Drinking Water Monitoring by Biological Early Warning Systems

DTIC Science & Technology

2005-03-18

Lepomis macrochirus). have been disinfected with chloramines The threshold for a toxicity alarm by was not determined. Biomonitor users the USACEHR...residual solution. This caused an elevated chlorine from water disinfected with chlorine level (measured at 0.08 FRC) chloramines . In testing with a rapid...have been disinfected A Handbook, Volume 2, 8. Kluwer with chloramines . Academic/Plenum Publishers, New York, NY, pp 123-141. 5. Recommendations

Microgravity simulations with human lymphocytes in the free fall machine and in the random positioning machine

NASA Technical Reports Server (NTRS)

Schwarzenberg, M.; Pippia, P.; Meloni, M. A.; Cossu, G.; Cogoli-Greuter, M.; Cogoli, A.

1998-01-01

The purpose of this paper is to present the results obtained in our laboratory with both instruments, the FFM [free fall machine] and the RPM [random positioning machine], to compare them with the data from earlier experiments with human lymphocytes conducted in the FRC [fast rotating clinostat] and in space. Furthermore, the suitability of the FFM and RPM for research in gravitational cell biology is discussed.

Large eddy simulation/dynamic thickened flame modeling of a high Karlovitz number turbulent premixed jet flame (Supplementary material).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Wang; Wang, Haiou; Kuenne, Guido

This supplementary material complements the article and provides additional information to the chemical mechanism used in this work, boundary conditions for the LES con guration and table generation, comparisons of axial velocities, results from a LES/ nite-rate chemistry (FRC) approach, and results from the LES/DTF/SPF approach with a particular chemistry table that is generated using a single strained premixed amelet solution.

Risk Management Approach & Progress in Cd and Cr6+ Elimination

DTIC Science & Technology

2014-11-18

Documentation Available by 2015? Gaps Conversion Coating- Aluminum Avionics/Electrical- Class 3 9 7 Medium yes- joint service/OEM/ NASA effort to...Optimized conditions validated by NASA . – FRC validation: immersion process – Based on data from the lab Surtec 650V optimization, an 1800-gallon tank...acting similarly, 650V not • Plans: scale up to 80 gallon process line; assess Metalast TCP/HF- EPA and Henkel products; further study 650V

Directed Energy HPM, PP, & PPS Efforts: Magnetized Target Fusion - Field Reversed Configuration

DTIC Science & Technology

2006-08-04

interior. 15. SUBJECT TERMS Magnetized Target Fusion (MTF), Field-Reversed Configuration (FRC), Alternative Confinement Concepts, Fusion Energy 16...research, the Department of Energy’s Office of Fusion Energy Studies (DOE OFES). Sections 2 through 4, which follow, describe in detail SAIC’s, FabTek’s...the plasma physics areas (FRCs and fusion energy ) in which we are working. The conference paper was submitted at this time, as well, and will

Analytical Model of Inlet Growth and Equilibrium Cross-Sectional Area

DTIC Science & Technology

2016-04-01

performance in a real-world setting. BACKGROUND: Long-term inlet stability in bar-built systems is determined by the tidal and wave forces that...across the node was limited due to convergence of the two incoming tidal waves . As such, the equivalent bay area was calculated using the midpoint as a...sediment transport is driven by tides and does not incorporate other forcing and associated sediment pathways. The ratio of wave to tidal energy is an

Occurrence and Trends of Selected Chemical Constituents in Bottom Sediment, Grand Lake O' the Cherokees, Northeast Oklahoma, 1940-2008

USGS Publications Warehouse

Juracek, Kyle E.; Becker, Mark F.

2009-01-01

After over 100 years of continuous activity, lead and zinc mining in the Tri-State Mining District (hereafter referred to as the TSMD) in parts of southeast Kansas, southwest Missouri, and northeast Oklahoma ended in the 1970s. The mining activity resulted in substantial historical and ongoing input of cadmium, lead, and zinc to the environment including Grand Lake O' the Cherokees (hereafter referred to as Grand Lake), a large reservoir in northeast Oklahoma. To help determine the extent and magnitude of contamination in Grand Lake, a one-year study was conducted by the U.S. Geological Survey in cooperation with the U.S. Fish and Wildlife Service. Bottom-sediment coring at five sites was used to investigate the occurrence of cadmium, lead, zinc, and other selected constituents in the bottom sediment of Grand Lake. Cadmium concentrations in the bottom sediment of Grand Lake ranged from 2.3 to 3.6 mg/kg (milligrams per kilogram) with a median of 3.5 mg/kg (5 samples). Compared to an estimated local background concentration of 0.6 mg/kg, the historical mining activity increased cadmium concentrations by about 280 to 500 percent. Lead concentrations ranged from 35 to 102 mg/kg with a median of 59 mg/kg (50 samples). Compared to an estimated local background concentration of 20 mg/kg, the historical mining activity increased lead concentrations by about 75 to 410 percent. The range in zinc concentrations was 380 to 986 mg/kg with a median of 765 mg/kg (50 samples). Compared to an estimated local background concentration of 100 mg/kg, the historical mining activity increased zinc concentrations by about 280 to 890 percent. With the exception of the most upstream coring site, the lead and zinc depositional profiles generally were similar in terms of the range in concentrations measured and the temporal pattern observed. Depositional profiles for lead and zinc indicated mid-core peaks followed by concentrations that decreased since about the 1980s. The depositional profiles reflect the complex interaction of several factors including historical mining and related activities, mine drainage, remediation, landscape stabilization, precipitation and associated runoff, and the erosion and transport of contaminated and clean sediments within the basin. Compared to sediment-quality guidelines, the Grand Lake samples had cadmium concentrations that were substantially less than the general probable-effects concentration (PEC) (4.98 mg/kg) and a TSMD-specific PEC (11.1 mg/kg). The PECs represent the concentration above which toxic biological effects are likely to occur. Likewise, all sediment samples had lead concentrations that were substantially less than the general PEC (128 mg/kg) and a TSMD-specific PEC (150 mg/kg). Zinc concentrations typically exceeded the general PEC (459 mg/kg), but were substantially less than a TSMD-specific PEC (2,083 mg/kg). Throughout the history of Grand Lake, lead and zinc concentrations in the deposited sediment did not approach or exceed the TSMD-specific PECs. As of 2008, legacy effects of mining still included the delivery of contaminated sediment to Grand Lake by the Spring and Neosho Rivers. The Neosho River, with its larger flows and less-contaminated sediment, likely dilutes the load of contaminated sediment delivered to Grand Lake by the Spring River. The information contained in this report provides a baseline of Grand Lake conditions with which to compare future conditions that may represent a response to changes in mining-related activity in the Grand Lake Basin.

Deriving sediment Interstitial Water Remediation Goals ...

EPA Pesticide Factsheets

Background/Objectives. Passive sampling is becoming a frequently used measurement technique at Superfund sites with contaminated sediments. Passive sampling measures the concentrations of freely dissolved chemicals (Cfrees) in the sediment interstitial water. The freely dissolved chemical is a good surrogate for and a very practical means for estimating the concentrations of bioavailable chemical in the sediments. Building from this approach, a methodology is proposed to derive sediment Interstitial Water Remediation Goals (IWRGs) for the protection of benthic organisms from direct toxicity using Cfrees measured with passive sampling.Approach/Activities. In the early 2000s, EPA developed and released Equilibrium Partitioning Sediment Benchmarks (ESBs) for a series of chemicals. ESBs are intended to be chemical concentrations below which unacceptable toxicity to benthic organisms does not occur. The ESBs (expressed with the units of ug/g OC) were derived using the equations:ESB= K_OC×FCV where K_OC=0.00028+0.983K_OWThe KOC is the organic carbon normalized sediment-water chemical partition coefficient, FCV is the Final Chronic Value from EPA’s ambient water quality criteria for the protection of aquatic life, and KOW is the n-octanol/water partition coefficient for the chemical. At a specific site, the remedial goal (CS:ESB µg/kg-dw) in sediment are then derived using the site-specific fraction of organic carbon in the sediment (fOC:SS) at the site:C_

Distribution of trace metals at Hopewell Furnace National Historic Site, Berks and Chester Counties, Pennsylvania

USGS Publications Warehouse

Sloto, Ronald A.; Reif, Andrew G.

2011-01-01

Hopewell Furnace, located approximately 50 miles northwest of Philadelphia, was a cold-blast, charcoal iron furnace that operated for 113 years (1771 to 1883). The purpose of this study by the U.S. Geological Survey, in cooperation with the National Park Service, was to determine the distribution of trace metals released to the environment from an historical iron smelter at Hopewell Furnace National Historic Site (NHS). Hopewell Furnace used iron ore from local mines that contained abundant magnetite and accessory sulfide minerals enriched in arsenic, cobalt, copper, and other metals. Ore, slag, cast iron furnace products, soil, groundwater, stream base flow, streambed sediment, and benthic macroinvertebrates were sampled for this study. Soil samples analyzed in the laboratory had concentrations of trace metals low enough to meet Pennsylvania Department of Environmental Protection standards for non-residential use. Groundwater samples from the supply well met U.S. Environmental Protection Agency drinking-water regulations. Concentrations of metals in surface-water base flow at the five stream sampling sites were below continuous concentration criteria for protection of aquatic organisms. Concentrations of metals in sediment at the five stream sites were below probable effects level guidelines for protection of aquatic organisms except for copper at site HF-3. Arsenic, copper, lead, zinc, and possibly cobalt were incorporated into the cast iron produced by Hopewell Furnace. Manganese was concentrated in slag along with iron, nickel, and zinc. The soil near the furnace has elevated concentrations of chromium, copper, iron, lead, and zinc compared to background soil concentrations. Concentrations of toxic elements were not present at concentrations of concern in water, soil, or stream sediments, despite being elevated in ore, slag, and cast iron furnace products. The base-flow surface-water samples indicated good overall quality. The five sampled sites generally had low concentrations of nutrients and major ions but had elevated concentrations of iron, manganese, and strontium when compared to sites sampled in adjacent watersheds. The background site on Baptism Creek generally had the lowest concentrations and yields of constituents. Low concentrations of nutrients and major ions at all five sites indicate that measured concentrations can be attributed to general land use and geology and not to point sources. Streambed-sediment sampling results indicated higher concentrations of all metals except nickel at sites on French Creek compared to the background site on Baptism Creek. Concentrations of aluminum, cadmium, and nickel were highest in sediment from the sampling site upstream from Hopewell Furnace. The highest concentrations of arsenic, boron, cobalt, copper, iron, lead, manganese, mercury, and zinc were detected at the site just below Hopewell Furnace, which indicates that the source of these metals may be in Hopewell Furnace NHS. The invertebrate community at the background site on Baptism Creek was dominated by pollution sensitive taxa indicating a healthy, diverse benthic-macroinvertebrate community. Benthic-macroinvertebrate communities at sampling sites on French Creek indicated disturbed communities when compared to the background site on Baptism Creek and that the overall stream quality immediately above and below Hopewell Furnace NHS is degraded. The benthic-macroinvertebrate communities were dominated by pollution-tolerant taxa, and taxa were less diverse than at the background site. Habitat conditions at the upstream site on French Creek were good but were degraded at downstream sites on French Creek. The major habitat issues at these sites were related to a lack of stable substrate, erosion, and deposition. Water quality and streambed-sediment quality do not indicate that the degraded benthic-macroinvertebrate communities are the result of poor water quality. Habitat conditions (erosion and sedimentation) and physical alterations (water temperature) from the outfall of Hopewell Lake are the most likely causes of the impaired communities.

Hydrogeochemical and stream sediment reconnaissance basic data report for Williams NTMS quadrangle, Arizona

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagoner, J.L.

Wet and dry sediments were collected throughout the 18,500-km/sup 2/arid-to-semiarid region and water samples at available streams, springs, and wells. Samples were collected between August 1977 and January 1978. Results of neutron activation analyses of uranium and trace elements and other field and laboratory analyses are presented in tabular hardcopy and microfiche format. The report includes six full-size overlays for use with the Williams NTMS 1:250,000 quadrangle. Sediment samples are divided into five general groups according to the source rock from which the sediment was derived. Background uranium concentrations for the quadrangle are relatively low, ranging from 1.91 to 2.40more » ppM, with the highest associated with the Precambrian igneous and metamorphic complexes of the Basin and Range province. Uranium correlates best with the rare-earth elements and iron, scandium, titanium, and manganese. Known uranium occurrences are not readily identified by the stream sediment data.« less

In-Well Sediment Incubators to Evaluate Microbial Community Stability and Dynamics following Bioimmobilization of Uranium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baldwin, Brett R.; Peacock, Aaron D.; Gan, M.

2009-09-23

An in-situ incubation device (ISI) was developed in order to investigate the stability and dynamics of sediment associated microbial communities to prevailing subsurface oxidizing or reducing conditions. Here we describe the use of these devices at the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site. During the 7 month deployment oxidized Rifle aquifer background sediments (RABS) were deployed in previously biostimulated wells under iron reducing conditions, cell densities of known iron reducing bacteria including Geobacteraceae increased significantly showing the microbial community response to local subsurface conditions. PLFA profiles of RABS following in situ deployment were strikingly similar to thosemore » of adjacent sediment cores suggesting ISI results could be extrapolated to the native material of the test plots. Results for ISI deployed reduced sediments showed only slight changes in community composition and pointed toward the ability of the ISIs to monitor microbial community stability and response to subsurface conditions.« less

Evaluation of potential relationships between benthic community structure and toxic metals in Laizhou Bay.

PubMed

Wu, Bin; Song, Jinming; Li, Xuegang

2014-10-15

The objective of the present study was to examine the relationships between benthic community structure and toxic metals using bivariate/multivariate techniques at 17 sediment locations in Laizhou Bay, North China. Sediment chemical data were evaluated against geochemical background values and sediment quality guidelines, which identified Cu and As as contaminants of concern with a moderate potential for adverse effects. Benthic community data were subjected to non-metric multidimensional scaling, which generated four groups of stations. Spearman rank correlation was then employed to explore the relationships between the major axes of heavy metals and benthic community structure. However, weak and insignificant correlations were found between these axes, indicating that contaminants of concern may not be the primary explanatory factors. Polychaeta were abundant in southern Laizhou Bay, serving as a warning regarding the health status of the ecosystem. Integrated sediment quality assessment showed sediments from northern central locations were impaired, displaying less diverse benthos and higher metal contamination. Copyright © 2014 Elsevier Ltd. All rights reserved.

Remobilization of metals from slag and polluted sediments (case study: the canal of the Deûle River, northern France).

PubMed

Vdović, Neda; Billon, Gabriel; Gabelle, Cédric; Potdevin, Jean-Luc

2006-05-01

The anthropogenic impact on the environment in the last century has proven to be very negative due to the fast development of industry. A typical example is the Deûle River in northern France, one of the most polluted sites in this region. The concentrations of Pb, Cd, Zn and Cu in river sediments are 300, 800, 50 and 15 times higher, respectively, than the background values. The present study was undertaken to evaluate the capacity of already polluted sediments to capture metals released from industrial wastes (slag). As it were, in spite of the high metal pollution level, sediments have still shown the ability to adsorb metals released from slag under the conditions provided. Their efficiency in "cleaning up" some of the metals (e.g. Pb) seems to be additionally enhanced in anoxic conditions. This study provided some additional information on the importance of sediments as a pollutant sink.

Comparison of E. coli, enterococci, and fecal coliform as indicators for brackish water quality assessment.

PubMed

Jin, Guang; Jeng, Huei-Wang; Bradford, Henry; Englande, A J

2004-01-01

Escherichia coli (E. coli), enterococci, and fecal coliform data were collected and compared as potential indicators for swimmablility assessment of a brackish waterbody (Lake Pontchartrain, Louisiana). These indicators were measured during lake background conditions, in stormwater runoff (before dilution with lake water), and in the outfall plume within the lake following storm events. Microbial indicator titers associated with suspended particles and lake-bottom sediments were also investigated. Overall reduction rate constants for fecal coliform, E. coli, and enterococci in lake water and sediment were measured and reported. Attachment of microbial indicators to suspended matter and subsequent sedimentation appeared to be a significant fate mechanism. A slower reduction rate of indicator organisms in sediment further suggested that bottom sediment may act as a reservoir for prolonging indicator organism survival and added concern of recontamination of overlaying waters due to potential solids resuspension. Results indicated that enterococci might be a more stable indicator than E. coli and fecal coliform and, consequently, a more conservative indicator under brackish water conditions.

Impact of Elevated CO2 on Trace Element Release from Aquifer Sediments of the San Joaquin Valley, CA

NASA Astrophysics Data System (ADS)

Fox, P. M.; Nico, P. S.; Davis, J. A.; Spycher, N.

2014-12-01

Carbon capture and storage (CCS) is a promising technique for mitigating climate change by storing large volumes of carbon dioxide in deep saline aquifers. In California, the thick marine sediments of the Central and Salinas Valleys have been identified as prime targets for future CO2 storage. However, the potential impacts on water quality of overlying drinking-water aquifers must be studied before CCS can be implemented. In this study, we compare trace element release from San Joaquin Valley aquifer sediments with a wide range of textural and redox properties. Kinetic batch experiments were performed with artificial groundwater continuously equilibrated under CO2-saturated (at 1 atm) and background CO2 (0.002-0.006 atm) conditions, resulting in a shift of nearly 3 pH units. In addition, the reversibility of trace element release was studied by sequentially lowering the CO2 from 1.0 atm to 0.5 atm to background concentrations (0.002-0.006 atm) for CO2-saturated systems in order to mimic the dissipation of a CO2 plume in the aquifer. During exposure to high CO2, a number of elements displayed enhanced release compared to background CO2 experiments (Ca, Mg, Li, Si, B, As, Sr, Ni, Fe, Mn, V, Ti, and Co) with concentrations of As, Fe, and Mn exceeding EPA maximum contaminant levels in some cases. On the other hand, Mo and U showed suppressed release. Most intriguing, many of the elements showing enhanced release displayed at least some degree of irreversibility when CO2 concentrations were decreased to background levels. In fact, in some cases (i.e., for V), an element showed further release when CO2 concentrations were decreased. These results suggest that there may be longer-term effects on groundwater quality that persist even after the CO2 plume has dissipated. Several different mechanisms of trace element release including ion exchange, desorption, and carbonate mineral dissolution are explored. Preliminary modeling results suggest that carbonate mineral dissolution can play a key role in driving trace element release even in sediments where carbonates are in low abundance.

The Forgotten Legacy: Sediment From Historical Gold Mining Greatly Exceeds all Other Anthropogenic Sources in SE Australian Rivers

NASA Astrophysics Data System (ADS)

Rutherfurd, I.; Davies, P.; Macklin, M. G.; Grove, J. R.

2016-12-01

Coarse and fine sediment has been a major pollutant of Australian rivers and receiving waters since European settlement in 1788. Anthropogenic sediment budget models demonstrate that catchment and channel erosion has increased background sediment delivery by 10 to 20 times across SE Australia, but these estimates ignore the contribution of historical gold mining. Detailed historical records allow us to reconstruct the delivery of coarse and fine sediment (including contaminated sediment) to the fluvial system. Between 1851 and 1900 alluvial gold mining in the state of Victoria liberated between 1.2 billion and 1.4 billion m3 of coarse and fine sediment into streams. Catchment scale modelling demonstrates that this volume is at least twice the volume of all anthropogenic (post-European) erosion from hillslopes, river banks, and gullies. We map the deposition and remobilization of these contaminated legacy mining sediments down selected valleys, and find that many contemporary floodplains are blanketed with mining sediments (although mercury contamination is present but low), and discrete sediment-slugs can be recognized migrating down river beds. Overall, the impact of gold mining is one of the strongest indicators of the Anthropocene in the Australian landscape, and the level of impact on rivers is substantially greater than recognized in the past. Perhaps of most interest is the rapid recovery of many river systems from the substantial impacts of gold mining. The result is that these major changes to the landscape are largely forgotten.

Using Snow to Teach Geology.

ERIC Educational Resources Information Center

Roth, Charles

1991-01-01

A lesson plan, directed at middle school students and older, describes using snow to study the geological processes of solidification of molten material, sedimentation, and metamorphosis. Provides background information on these geological processes. (MCO)

Prehospital Medicine and the Future Will ECMO Ever Play a Role?

PubMed

Macku, David; Hedvicak, Pavel; Quinn, John; Bencko, Vladimir

Due to the hybrid warfare currently experienced by multiple NATO coalition and NATO partner nations, the tactical combat casualty care (TCCC) paradigm is greatly challenged. One of the major challenges to TCCC is the ad hoc extension phase in resource-poor environments, referred to as prolonged field care (PFC) and forward resuscitative care (FRC). The nuanced clinical skills with limited resources required by warfighters and auxiliary health care professionals to mitigate death on the battlefield and prevent morbidity and mortality in the PFC phase represent a balance that is still under review. The aim of our article is to describe the connection between extracorporeal membrane oxygenation (ECMO) or the extracorporeal life support (ECLS) treatment and its possible improvement in prehospital trauma care, at a Role 1 or 2 facility and, more provocatively, in the PFC phase of care in the future through innovative technology and how it connects with FRC. We report and describe here the primary components of ECMO/ECLS and present the main concept of a human extracorporeal circulation cocoon as a transitional living form for the cardiopulmonary stabilization of wounded combatants on the battlefield and their transportation to higher echelons of care and treatment facilities (to include damage control resuscitation [DCR] and damage control surgery [DCS]). As clinical governance, these matters would fall within the remit of the Committee on Surgical Combat Casualty Care (CoSCCC) and the Committee on Enroute Combat Casualty Care (CoERCCC), and it is within this framework that we propose this concept piece of ECMO in the prehospital space. We caution that this report is a proposed innovation to TCCC but also serves to push the envelope of the PFC and FRC paradigm. What we propose will not change the practice this year, but as ECMO technology progresses, it may change our practice within the next decade. We conclude with proposed novel future research to save life on the battlefield with ECMO as a major challenge and one worth the focus of further research. Medicine is controversial and constantly changing; for those who work in prehospital and battlefield medicine, change is the only constant on which we rely, and without provocative discussion that makes our systems and practice more robust, we will fail. 2018.

Preliminary post-emplacement safety analysis of the subseabed disposal of high-level nuclear waste

NASA Astrophysics Data System (ADS)

Kaplan, M. F.; Koplik, C. M.; Klett, R. D.

1984-09-01

The radiological hazard from the disposal of high-level nuclear waste within the deep ocean sediments is evaluated, on a preliminary basis, for locations in the central North Pacific and in the northwestern Atlantic. Radio-nuclide transport in the sediment and water column and by marine organisms is considered. Peak doses to an individual are approximately five orders of magnitude below background levels for both sites. Sensitivity analyses for most aspects of the post-emplacement systems models are included.

Environmental Radioactivity Study in Surface Sediments of Guacanayabo Gulf (Cuba)

NASA Astrophysics Data System (ADS)

Reyes, H.; López-Pino, N.; Rizo, O. Díaz; Bernal, J. L.; D'Alessandro, K.; Padilla, F.; Corrales, Y.; Casanova, O. A.; Gelen, A.; Martínez, Y.; Aguilar, J.; Arado, J. O.; Maidana, N. L.

2009-06-01

Sediment samples have been collected in the Guacanayabo gulf located in the southeast Cuba, to determinate the radioactivity levels of 210Pb, 234Th, 214Pb, 137Cs, 232Th and 40K using Low-Background Gamma Spectrometry and to evaluate its impact in the habitat of important marine species for fishery industry. The obtained results show the lowest radioactivity levels determined in Cuban marine environments. The species capture declination in the last years is not originated by radioactive pollution of the zone.

Regional Morphology Analysis Package (RMAP): Empirical Orthogonal Function Analysis, Background and Examples

DTIC Science & Technology

2007-10-01

1984. Complex principal component analysis : Theory and examples. Journal of Climate and Applied Meteorology 23: 1660-1673. Hotelling, H. 1933...Sediments 99. ASCE: 2,566-2,581. Von Storch, H., and A. Navarra. 1995. Analysis of climate variability. Applications of statistical techniques. Berlin...ERDC TN-SWWRP-07-9 October 2007 Regional Morphology Empirical Analysis Package (RMAP): Orthogonal Function Analysis , Background and Examples by

Environmental Forensics

DTIC Science & Technology

2011-03-29

Ethanol Benzophenone Benzophenone Stearyl alcohol Stearyl alcohol Fragrances Fragrances Shampoo Lipstick Benzaldehyde Glycerin Methylene Chloride...MatchInconclusiveMatchConclusion NO YES Unknown Coastal Background Sediments: National Survey  0 10 cm depth composites A-  Analytical Methods (EPA SW

Mineral precipitation and dissolution at two slag-disposal sites in northwestern Indiana, USA

USGS Publications Warehouse

Bayless, E.R.; Schulz, M.S.

2003-01-01

Slag is a ubiquitous byproduct of the iron- and steel-refining industries. In northwestern Indiana and northeastern Illinois, slag has been deposited over more than 52 km2 of land surface. Despite the widespread use of slag for fill and construction purposes, little is known about its chemical effects on the environment. Two slagdisposal sites were examined in northwestern Indiana where slag was deposited over the native glacial deposits. At a third site, where slag was not present, background conditions were defined. Samples were collected from cores and drill cuttings and described with scanning electron microscopy and electron microprobe analysis. Ground-water samples were collected and used to assess thermodynamic equilibria between authigenic minerals and existing conditions. Differences in the mineralogy at background and slag-affected sites were apparent. Calcite, dolomite, gypsum, iron oxides, and clay minerals were abundant in native sediments immediately beneath the slag. Mineral features indicated that these minerals precipitated rapidly from slag drainage and co-precipitated minor amounts of non-calcium metals and trace elements. Quartz fragments immediately beneath the slag showed extensive pitting that was not apparent in sediments from the background site, indicating chemical weathering by the hyperalkaline slag drainage. The environmental impacts of slag-related mineral precipitation include disruption of natural ground-water flow patterns and bed-sediment armoring in adjacent surface-water systems. Dissolution of native quartz by the hyperalkaline drainage may cause instability in structures situated over slag fill or in roadways comprised of slag aggregates.

Clostridium perfringens in Long Island Sound sediments: An urban sedimentary record

USGS Publications Warehouse

Buchholtz ten Brink, Marilyn R.; Mecray, E.L.; Galvin, E.L.

2000-01-01

Clostridium perfringens is a conservative tracer and an indicator of sewage-derived pollution in the marine environment. The distribution of Clostridium perfringens spores was measured in sediments from Long Island Sound, USA, as part of a regional study designed to: (1) map the distribution of contaminated sediments; (2) determine transport and dispersal paths; (3) identify the locations of sediment and contaminant focusing; and (4) constrain predictive models. In 1996, sediment cores were collected at 58 stations, and surface sediments were collected at 219 locations throughout the Sound. Elevated concentrations of Clostridium perfringens in the sediments indicate that sewage pollution is present throughout Long Island Sound and has persisted for more than a century. Concentrations range from undetectable amounts to 15,000 spores/g dry sediment and are above background levels in the upper 30 cm at nearly all core locations. Sediment focusing strongly impacts the accumulation of Clostridium perfringens spores. Inventories in the cores range from 28 to 70,000 spores/cm2, and elevated concentrations can extend to depths of 50 cm. The steep gradients in Clostridium perfringens profiles in muddier cores contrast with concentrations that are generally constant with depth in sandier cores. Clostridium perfringens concentrations rarely decrease in the uppermost sediment, unlike those reported for metal contaminants. Concentrations in surface sediments are highest in the western end of the Sound, very low in the eastern region, and intermediate in the central part. This pattern reflects winnowing and focusing of Clostridium perfringens spores and fine-grained sediment by the hydrodynamic regime; however, the proximity of sewage sources to the westernmost Sound locally enhances the Clostridium perfringens signals.

Preliminary report on mercury geochemistry of placer gold dredge tailings, sediments, bedrock, and waters in the Clear Creek restoration area, Shasta County, California

USGS Publications Warehouse

Ashley, Roger P.; Rytuba, James J.; Rogers, Ronald; Kotlyar, Boris B.; Lawler, David

2002-01-01

Clear Creek, one of the major tributaries of the upper Sacramento River, drains the eastern Trinity Mountains. Alluvial plain and terrace gravels of lower Clear Creek, at the northwest edge of the Sacramento Valley, contain placer gold that has been mined since the Gold Rush by various methods including dredging. In addition, from the 1950s to the 1980s aggregate-mining operations removed gravel from the lower Clear Creek flood plain. Since Clear Creek is an important stream for salmon production, a habitat restoration program is underway to repair damage from mining and improve conditions for spawning. This program includes using dredge tailings to fill in gravel pits in the flood plain, raising the concern that mercury lost to these tailings in the gold recovery process may be released and become available to biota. The purposes of our study are to determine concentrations and speciation of mercury in sediments, tailings, and water in the lower Clear Creek area, and to determine its mobility. Mercury concentrations in bedrock and unmined gravels both within and above the mined area are low, and are taken to represent background concentrations. Bulk mercury values in flood-plain sediments and dry tailings are elevated to several times these background concentrations. Mercury in sediments and tailings is associated with fine size fractions. Although methylmercury levels are generally low in sediments, shallow ponds in the flood plain may have above-normal methylation potential. Stream waters in the area show low mercury and methylmercury levels. Ponds with elevated methylmercury in sediments have more methylmercury in their waters as well. One seep in the area is highly saline, and enriched in mercury, lithium, and boron, similar to connate waters that are expelled along thrust faults to the south on the west side of the Sacramento Valley. This occurrence suggests that mercury in waters may at least in part be from sources other than placer mining.

Metalliferous sediments from Eolo Seamount (Tyrrhenian Sea): Hydrothermal deposition and re-deposition in a zone of oxygen depletion

USGS Publications Warehouse

Dekov, V.M.; Kamenov, George D.; Savelli, C.; Stummeyer, Jens; Thiry, M.; Shanks, Wayne C.; Willingham, A.L.; Boycheva, T.B.; Rochette, P.; Kuzmann, E.; Fortin, D.; Vertes, A.

2009-01-01

A sediment core taken from the south-east slope of the Eolo Seamount is composed of alternating red-brown and light-brown to bluish-grey layers with signs of re-deposition in the middle-upper section. The red-brown layers are Fe-rich metalliferous sediments formed as a result of low-temperature (??? 77????C) hydrothermal discharge, whereas the bluish-grey layers most probably originated from background sedimentation of Al-rich detrital material. The metalliferous layers are composed mainly of Si-rich goethite containing some Al. Co-precipitation of hydrothermally released SiO44- and Fe2+ as amorphous or poorly crystalline Fe-Si-oxyhydroxides explains the high Si concentration in goethite. The elevated Al content of the goethite is fairly unusual, but reflects the extremely high background Al content of the Tyrrhenian seawater due to the high eolian terrigenous flux from the Sahara desert. The Sr and Nd isotope data suggest that the Eolo metalliferous sediments are the product of a 3-component mixture: hydrothermal fluid, seawater, and detrital material (Saharan dust and Aeolian Arc material). The enrichment in Fe, P, As, Mo, Cd, Be, Sb, W, Y, V, depletion in REE and transition elements (Cu, Co, Ni, Zn) and the REE distribution patterns support the low-temperature hydrothermal deposition of the metalliferous layers. The hydrothermal field is located in a seawater layer of relative O2 depletion, which led to a significant fractionation of the hydrothermally emitted Fe and Mn. Fe-oxyhydroxides precipitated immediately around the vents whereas Mn stayed in solution longer and the Mn-oxides precipitated higher up on the seamount slope in seawater with relatively higher O2 levels. High seismic activity led to sediment re-deposition and slumping of the Mn-rich layers down slope and mixing with the Fe-rich layers. ?? 2009 Elsevier B.V. All rights reserved.

[Spatial Distribution and Potential Ecological Risk Assessment of Heavy Metals in Soils and Sediments in Shunde Waterway, Southern China].

PubMed

Cai, Yi-min; Chen, Wei-ping; Peng, Chi; Wang, Tie-yu; Xiao, Rong-bo

2016-05-15

Environmental quality of soils and sediments around water source area can influence the safety of potable water of rivers. In order to study the pollution characteristics, the sources and ecological risks of heavy metals Zn, Cr, Pb, Cu, Ni and Cd in water source area, surface soils around the waterway and sediments in the estuary of main tributaries were collected in Shunde, and ecological risks of heavy metals were assessed by two methods of potential ecological risk assessment. The mean contents of Zn, Cr, Pb, Cu, Ni and Cd in the surface soils were 186.80, 65.88, 54.56, 32.47, 22.65 and 0.86 mg · kg⁻¹ respectively, and they were higher than their soil background values except those of Cu and Ni. The mean concentrations of Zn, Cr, Pb, Cu, Ni and Cd in the sediments were 312.11, 111.41, 97.87, 92.32, 29.89 and 1.72 mg · kg⁻¹ respectively, and they were higher than their soil background values except that of Ni. The results of principal component analysis illustrated that the main source of Cr and Ni in soils was soil parent materials, and Zn, Pb, Cu and Cd in soils mainly came from wastewater discharge of local manufacturing industry. The six heavy metals in sediments mainly originated from industry emissions around the Shunde waterway. The results of potential ecological risk assessment integrating environmental bioavailability of heavy metals showed that Zn, Cu, Pb and Ni had a slight potential ecological risk. Cd had a slight potential ecological risk in surface soils, but a moderate potential ecological risk in surfaces sediments. Because the potential ecological risk assessment integrating environmental bioavailability of heavy metals took the soil properties and heavy metal forms into account, its results of risks were lower than those of Hakanson methods, and it could avoid overestimating the potential risks of heavy metals.

Sedimentology and geochemistry of mud volcanoes in the Anaximander Mountain Region from the Eastern Mediterranean Sea.

PubMed

Talas, Ezgi; Duman, Muhammet; Küçüksezgin, Filiz; Brennan, Michael L; Raineault, Nicole A

2015-06-15

Investigations carried out on surface sediments collected from the Anaximander mud volcanoes in the Eastern Mediterranean Sea to determine sedimentary and geochemical properties. The sediment grain size distribution and geochemical contents were determined by grain size analysis, organic carbon, carbonate contents and element analysis. The results of element contents were compared to background levels of Earth's crust. The factors that affect element distribution in sediments were calculated by the nine push core samples taken from the surface of mud volcanoes by the E/V Nautilus. The grain size of the samples varies from sand to sandy silt. Enrichment and Contamination factor analysis showed that these analyses can also be used to evaluate of deep sea environmental and source parameters. It is concluded that the biological and cold seep effects are the main drivers of surface sediment characteristics from the Anaximander mud volcanoes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Engineer’s Handbook. Central Archive for Reusable Defense Software (CARDS)

DTIC Science & Technology

1994-02-28

benefit frc- this reuse effort? Reuse should be done for a domain rather than just for a program. " Identify relationships between domains to facilitate... benefits to the government and its contractors. " Help provide guidelines to enable domain managers to do a trade-off study on requirements, e.g., does...libraries, if desired or required. This can only occur where the government domain growth matches, or can benefit from, the inclusion or incorporation of the

Replacement of Chromium Electroplating on Helicopter Dynamic Components Using HVOF Thermal Spray Technology

DTIC Science & Technology

2009-11-01

quality control RCRA Resource Conservation and Recovery Act SAE Society for Automotive Engineers S-N stress vs number of cycles (fatigue curve...Automotive Engineers ( SAE ) Aerospace Materials Specifications (AMS): Figure 3. Air handler and dust filter installation at FRC-E. 8 - AMS 2447 was...developed with the assistance of the HCAT team and issued by SAE in 1998. It is now a widely used standard in the aerospace industry. - AMS 2448

Annual Report 2015: High Fidelity Modeling of Field-Reversed Configuration (FRC) Thrusters

DTIC Science & Technology

2016-06-01

simulations become unstable as time evolves leading to the magnetic island collision with the boundary and destruction of the close magnetic field structure...compares well with the results of the Hall-MHD code. 1 R. D. Milroy, "A magnetohydrodynamic model of rotating magnetic field current drive in a field...reversed configuration," Physics of Plasmas, vol. 7, no. 10. 2 Distribution A: Approved for Public Release. PA# 16202 Figure 1. Magnetic field

Development, Vibration, and Thermal Characterization of a Steady Operating Pulsed Power System for FRC Thrusters

DTIC Science & Technology

2015-04-01

to successfully operate after being exposed to the harsh launch vibration environment. 2. Uncover workmanship flaws such as loose fasteners or weak...uncover any workmanship errors in spite of exposing the PPUs to vibration levels in excess of what is expected for flight on any of the launchers ...successfully operate after being exposed to the harsh launch vibration environment. 2. Uncover workmanship flaws such as loose fasteners or weak

Effects of umeclidinium/vilanterol on exercise endurance in COPD: a randomised study.

PubMed

Riley, John H; Kalberg, Chris J; Donald, Alison; Lipson, David A; Shoaib, Muhammad; Tombs, Lee

2018-01-01

This multicentre, randomised, double-blind, placebo-controlled, two-period crossover study assessed the effect of umeclidinium/vilanterol (UMEC/VI) on exercise capacity in patients with chronic obstructive pulmonary disease (COPD) using the endurance shuttle walk test (ESWT). Patients were randomised 1:1 to one of two treatment sequences: 1) UMEC/VI 62.5/25 µg followed by placebo or 2) placebo followed by UMEC/VI 62.5/25 µg. Each treatment was taken once daily for 12 weeks. The primary end-point was 3-h post-dose exercise endurance time (EET) at week 12. Secondary end-points included trough forced expiratory volume in 1 s (FEV 1 ) and 3-h post-dose functional residual capacity (FRC), both at week 12. COPD Assessment Test (CAT) score at week 12 was also assessed. UMEC/VI treatment did not result in a statistically significant improvement in EET change from baseline at week 12 versus placebo (p=0.790). However, improvements were observed in trough FEV 1 (206 mL, 95% CI 167-246), 3-h post-dose FRC (-346 mL, 95% CI -487 to -204) and CAT score (-1.07 units, 95% CI -2.09 to -0.05) versus placebo at week 12. UMEC/VI did not result in improvements in EET at week 12 versus placebo, despite improvements in measures of lung function, hyperinflation and health status.

Composite Bus Structure for the SMEX/WIRE Satellite

NASA Technical Reports Server (NTRS)

Rosanova, Giulio G.

1998-01-01

In an effort to reduce the weight and optimize the structural design of the Small Explorer (SMEX) Wide-Field Infrared Explorer (WIRE) spacecraft, it has become desirable to change the material and construction from mechanically fastened aluminum structure to a fully bonded fiber-reinforced composite (FRC) structure. GSFC has developed the WIRE spacecraft structural bus design concept, including the instrument and launch vehicle requirements. The WIRE Satellite is the fifth of a series of SMEX satellites to be launched once per year. GSFC has chosen Composite Optics Inc. (COI) as the prime contractor for the development and procurement of the WIRE composite structure. The detailed design of the fully bonded FRC structure is based on COI's Short Notice Accelerated Production SATellite ("SNAPSAT") approach. SNAPSAT is a state of the art design and manufacturing technology for advanced composite materials which utilizes flat-stock detail parts bonded together to produce a final structural assembly. The structural design approach adopted for the WIRE structure provides a very viable alternative to both traditional aluminum construction as well as high tech. molded type composite structures. This approach to composite structure design is much less costly than molded or honeycomb sandwich type composite construction, but may cost slightly more than conventional aluminum construction on the subsystem level. However on the overall program level the weight saving achieved is very cost effective, since the primary objective is to allocate more mass for science payloads.

Coupled transport in field-reversed configurations

NASA Astrophysics Data System (ADS)

Steinhauer, L. C.; Berk, H. L.; TAE Team

2018-02-01

Coupled transport is the close interconnection between the cross-field and parallel fluxes in different regions due to topological changes in the magnetic field. This occurs because perpendicular transport is necessary for particles or energy to leave closed field-line regions, while parallel transport strongly affects evolution of open field-line regions. In most toroidal confinement systems, the periphery, namely, the portion with open magnetic surfaces, is small in thickness and volume compared to the core plasma, the portion with closed surfaces. In field-reversed configurations (FRCs), the periphery plays an outsized role in overall confinement. This effect is addressed by an FRC-relevant model of coupled particle transport that is well suited for immediate interpretation of experiments. The focus here is particle confinement rather than energy confinement since the two track together in FRCs. The interpretive tool yields both the particle transport rate χn and the end-loss time τǁ. The results indicate that particle confinement depends on both χn across magnetic surfaces throughout the plasma and τǁ along open surfaces and that they provide roughly equal transport barriers, inhibiting particle loss. The interpretation of traditional FRCs shows Bohm-like χn and inertial (free-streaming) τǁ. However, in recent advanced beam-driven FRC experiments, χn approaches the classical rate and τǁ is comparable to classic empty-loss-cone mirrors.

Global electrostatic potential structures of merging flux tubes in TS-U torus plasma merging experiment

NASA Astrophysics Data System (ADS)

Sawada, Asuka; Hatano, Hironori; Akimitsu, Moe; Cao, Qinghong; Yamasaki, Kotaro; Tanabe, Hiroshi; Ono, Yasushi; TS-Group Team

2017-10-01

We have been investigating 2D potential profile of global merging tokamaks to solve high-power heating of magnetic reconnection in TS-3 and TS-3U (ST, FRC:R =0.2m, 1985-, 2017-) and TS-4 (ST, FRC:R =0.5m, 2000-), UTST (ST:R =0.45m, 2008-) and MAST (ST:R = 0.9m, 2000-) devices. These experiments made clear that the electrostatic potential well is formed not only in the downstream area of magnetic reconnection but also in the whole common (reconnected) flux area of two merging flux tubes: tokamak plasmas. This fact suggests that the ion acceleration/heating occurs in much wider region than the reconnection downstream. We studied how the potential structure depends on key reconnection parameters:guide toroidal field and plasma collisionality. We found the polarity of the guide toroidal field determines those of potential hills and wells, indicating their formation is affected by the Hall effect. The peak value of the electrostatic potential well decreased with gas pressure increasing, suggesting plasma collisionality suppresses the Hall effect. The relationship between the electrostatic potential structure and anomalous ion heating is being studied as a possible cause for the high-power heating of fast magnetic reconnection. This work was supported by JSPS KAKENHI Grant Numbers 15H05750, 15K14279 and 17H04863.

Lung volume, breathing pattern and ventilation inhomogeneity in preterm and term infants.

PubMed

Latzin, Philipp; Roth, Stefan; Thamrin, Cindy; Hutten, Gerard J; Pramana, Isabelle; Kuehni, Claudia E; Casaulta, Carmen; Nelle, Matthias; Riedel, Thomas; Frey, Urs

2009-01-01

Morphological changes in preterm infants with bronchopulmonary dysplasia (BPD) have functional consequences on lung volume, ventilation inhomogeneity and respiratory mechanics. Although some studies have shown lower lung volumes and increased ventilation inhomogeneity in BPD infants, conflicting results exist possibly due to differences in sedation and measurement techniques. We studied 127 infants with BPD, 58 preterm infants without BPD and 239 healthy term-born infants, at a matched post-conceptional age of 44 weeks during quiet natural sleep according to ATS/ERS standards. Lung function parameters measured were functional residual capacity (FRC) and ventilation inhomogeneity by multiple breath washout as well as tidal breathing parameters. Preterm infants with BPD had only marginally lower FRC (21.4 mL/kg) than preterm infants without BPD (23.4 mL/kg) and term-born infants (22.6 mL/kg), though there was no trend with disease severity. They also showed higher respiratory rates and lower ratios of time to peak expiratory flow and expiratory time (t(PTEF)/t(E)) than healthy preterm and term controls. These changes were related to disease severity. No differences were found for ventilation inhomogeneity. Our results suggest that preterm infants with BPD have a high capacity to maintain functional lung volume during natural sleep. The alterations in breathing pattern with disease severity may reflect presence of adaptive mechanisms to cope with the disease process.

Surface modification of quartz fibres for dental composites through a sol-gel process.

PubMed

Wang, Yazi; Wang, Renlin; Habib, Eric; Wang, Ruili; Zhang, Qinghong; Sun, Bin; Zhu, Meifang

2017-05-01

In this study, quartz fibres (QFs) surface modification using a sol-gel method was proposed and dental posts reinforced with modified QFs were produced. A silica sol (SS) was prepared using tetraethoxysilane (TEOS) and 3-methacryloxypropyltrimethoxysilane (γ-MPS) as precursors. The amount of γ-MPS in the sol-gel system was varied from 0 to 24wt.% with a constant molar ratio of TEOS, ethanol, deionized water, and HCl. Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and contact angle (CA) measurements were used to characterize the modified QFs, which confirmed that SS had successfully coated the surface of QFs. SEM images showed good interfacial bonding between the modified QFs and the resin matrix. The results of three-point bending tests of the fibre reinforced composite (FRC) posts showed that the QFs modified by SS with 12wt.% γ-MPS presented the best mechanical properties, demonstrating improvements of 108.3% and 89.6% for the flexural strength and flexural modulus, respectively, compared with untreated QFs. Furthermore, the sorption and solubility of the prepared dental posts were also studied by immersing the posts in artificial saliva (AS) for 4weeks, and yielded favourable results. This sol-gel surface modification method promises to resolve interfacial bonding issues of fibres with the resin matrix, and produce FRC posts with excellent properties. Copyright © 2017. Published by Elsevier B.V.

Interaction of Fast Ions with Global Plasma Modes in the C-2 Field Reversed Configuration Experiment

NASA Astrophysics Data System (ADS)

Smirnov, Artem; Dettrick, Sean; Clary, Ryan; Korepanov, Sergey; Thompson, Matthew; Trask, Erik; Tuszewski, Michel

2012-10-01

A high-confinement operating regime [1] with plasma lifetimes significantly exceeding past empirical scaling laws was recently obtained by combining plasma gun edge biasing and tangential Neutral Beam Injection (NBI) in the C-2 field-reversed configuration (FRC) experiment [2, 3]. We present experimental and computational results on the interaction of fast ions with the n=2 rotational and n=1 wobble modes in the C-2 FRC. It is found that the n=2 mode is similar to quadrupole magnetic fields in its detrimental effect on the fast ion transport due to symmetry breaking. The plasma gun generates an inward radial electric field, thus stabilizing the n=2 rotational instability without applying the quadrupole magnetic fields. The resultant FRCs are nearly axisymmetric, which enables fast ion confinement. The NBI further suppresses the n=2 mode, improves the plasma confinement characteristics, and increases the plasma configuration lifetime [4]. The n=1 wobble mode has relatively little effect on the fast ion transport, likely due to the approximate axisymmetry about the displaced plasma column. [4pt] [1] M. Tuszewski et al., Phys. Rev. Lett. 108, 255008 (2012).[0pt] [2] M. Binderbauer et al., Phys. Rev. Lett. 105, 045003 (2010).[0pt] [3] H.Y. Guo et al., Phys. Plasmas 18, 056110 (2011).[0pt] [4] M. Tuszewski et al., Phys. Plasmas 19, 056108 (2012)

Multiple breath washout analysis in infants: quality assessment and recommendations for improvement.

PubMed

Anagnostopoulou, Pinelopi; Egger, Barbara; Lurà, Marco; Usemann, Jakob; Schmidt, Anne; Gorlanova, Olga; Korten, Insa; Roos, Markus; Frey, Urs; Latzin, Philipp

2016-03-01

Infant multiple breath washout (MBW) testing serves as a primary outcome in clinical studies. However, it is still unknown whether current software algorithms allow between-centre comparisons. In this study of healthy infants, we quantified MBW measurement errors and tried to improve data quality by simply changing software settings. We analyzed best quality MBW measurements performed with an ultrasonic flowmeter in 24 infants from two centres in Switzerland with the current software settings. To challenge the robustness of these settings, we also used alternative analysis approaches. Using the current analysis software, the coefficient of variation (CV) for functional residual capacity (FRC) differed significantly between centres (mean  ±  SD (%): 9.8  ±  5.6 and 5.8  ±  2.9, respectively, p  =  0.039). In addition, FRC values calculated during the washout differed between  -25 and  +30% from those of the washin of the same tracing. Results were mainly influenced by analysis settings and temperature recordings. Changing few algorithms resulted in significantly more robust analysis. Non-systematic inter-centre differences can be reduced by using correctly recorded environmental data and simple changes in the software algorithms. We provide implications that greatly improve infant MBW outcomes' quality and can be applied when multicentre trials are conducted.