Pharmacokinetic analysis of flomoxef in children undergoing cardiopulmonary bypass and modified ultrafiltration.

PubMed

Masuda, Zenichi; Kurosaki, Yuji; Ishino, Kozo; Yamauchi, Keita; Sano, Shunji

2008-04-01

Cardiopulmonary bypass (CPB) induces changes in the pharmacokinetics of drugs. The purpose of this study was to model the pharmacokinetics of flomoxef, a cephalosporin antibiotic, in pediatric cardiac surgery. Each patient received a flomoxef dose of 30 mg/kg as a bolus after the induction of anesthesia and an additional dose (1 g for a child weighing < 10 kg, 2 g for > or = 10 kg) was injected into the CPB prime. Modified ultrafiltration (MUF) was routinely performed. Blood samples, urine, and ultrafiltrate were collected. In seven patients (group I), serum flomoxef concentration-time courses were analyzed by a modified two-compartment model. Utilizing the estimated parameters, serum concentrations were simulated in another eight patients (group II). The initiation of CPB resulted in an abrupt increase in serum flomoxef concentrations in group I; however, concentrations declined biexponentially. The amount of excreted flomoxef in the urine and by MUF was 47% +/- 8% of the total administered dose. In group II, an excellent fit was found between the values calculated by the program and the observed serum concentrations expressed; most of the performance errors were <1.0. There was no difference in any kinetic parameter between group I and groups I + II (n = 15). The pharmacokinetics of flomoxef in children undergoing CPB and MUF were well fitted to a modified two-compartment model. Using the kinetic data from this study, the individualization of dosage regimens for prophylactic use of flomoxef might be possible.

[Inbreeding process and establishment of new inbred lines derived from the Japanese house mouse, Mus musculus molossinus].

PubMed

Nomaguchi, T A; Sakurai, Y

1993-04-01

Inbreeding of 8 groups in molossinus mouse began in (Miura female x Urawa male) F1 (MU) from the stock captured in the Kanto district of Japan and were accomplished by each primiparous littermates. The animals were kept under a clean conventional condition at 23.5 +/- 2.5 degrees C and 50 +/- 5% in relative humidity. Pellet feed, CRF-1, and tap water were provided ad libitum. The respective number of inbreeding generations of MUA, MUF and MUG now exceeds F21, F20 and F22, respectively. Inbreeding of MUD and MUE have reached to F18 up to now, but the other 3 groups became extinct at F10. Time required for inbreeding from F0 to F20 was 2,280 days for MUA, 2,454 days for MUF and 2,143 days for MUG. Generation time was 114.0 +/- 47.2 days for MUA, 122.7 +/- 54.6 days for MUF and 107.2 +/- 48.5 days for MUG. Though the generation time varied from a minimum of 60 days to a maximum of 258 days from F0 to F10 in the inbreeding process (mean: 150.2 +/- 41.7 days), which were shortened from F10 and the mean was 79.0 +/- 29.1 days. In the breeding of the molossinus mouse, primiparous age was 124.5 +/- 29.7 days from F0 to F9 and 77.8 +/- 9.3 days from F10 to F19. The litter size was 5.1 +/- 1.3 for MUA and 5.0 +/- 1.3 for MUG in offspring, 5.0 +/- 1.2 and 4.9 +/- 1.2 in weanling, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanism of Void Prediction in Flip Chip Packages with Molded Underfill

NASA Astrophysics Data System (ADS)

Wu, Kuo-Tsai; Hwang, Sheng-Jye; Lee, Huei-Huang

2017-08-01

Voids have always been present using the molded underfill (MUF) package process, which is a problem that needs further investigation. In this study, the process was studied using the Moldex3D numerical analysis software. The effects of gas (air vent effect) on the overall melt front were also considered. In this isothermal process containing two fluids, the gas and melt colloid interact in the mold cavity. Simulation enabled an appropriate understanding of the actual situation to be gained, and, through analysis, the void region and exact location of voids were predicted. First, the global flow end area was observed to predict the void movement trend, and then the local flow ends were observed to predict the location and size of voids. In the MUF 518 case study, simulations predicted the void region as well as the location and size of the voids. The void phenomenon in a flip chip ball grid array underfill is discussed as part of the study.

Ionospheric Propagation Studies during the Precision Targeting Experiments.

DTIC Science & Technology

1986-01-01

Figure 7 where the mission time is expanded. Figure 7 also shows the MOFF2 and MOFFI as measured directly aboard the aircraft receiving the wideband...terms of the MUF. Questions as to target amplitude and subclutter visibility must also be looked at in detail. During the entire mission MOFF2 > MOFFI

Analysis of cocondensation of melamine and urea through carbon 13 enriched formaldehyde with C-13 nuclear magnetic resonance spectroscopy

Treesearch

Bunichiro Tomita; Chung-Yun Hse

1995-01-01

The urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins, and melamine-ureaformaldehyde (MUF) cocondensed resins were synthesized using the labeling method with 13C enriched formaldehyde under neutral conditions and their 13C-NMR (nuclear magnetic resonance) spectra were analyzed. The remarkable down-field...

Analysis on cocondensation of melamine and urea through carbon 13 enriched formaldehyde with carbon 13 nuclear magnetic resonance spectroscopy

Treesearch

Bunichiro Tomita; Chung-Yun Hse

1995-01-01

The urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins, and melamine-urea-formaldehyde (MUF) cocondensed resins were synthesized using the labeling method of 13C enriched formaldehyde udner neutral conditions and their 13C-NMR (nuclear magnetic resonance) spectra were analyzed. The remarkable down-field shifts...

Analyses of cocondensation of melamine and urea through formaldehyde with carbon 13 nuclear magnetic resonance spectroscopy

Treesearch

Tomita Bunchiro; Chung-Yun Hse

1995-01-01

The 13C-NMR (carbon 13 nuclear magnetic resonance) spectra of urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins, and melamine-urea-formaldehyde (MUF) cocondensed resins synthesized under various conditions were taken with a frequency of 75 MHz. The main purpose was to investigate whether or not the occurrences of cocondensation...

Analyses of cocondensation of melamine and urea through carbon 13 enriched formaldehyde with carbon 13 nuclear magnetic resonance spectroscopy

Treesearch

Tomita Bunchiro; Chung-Yun Hse

1995-01-01

The urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins, and melamine-urea-formaldehyde (MUF) cocondensed resins were synthesized using the labeling method with 13C enriched formaldehyde unde neutral conditions and their 13C-NMR (nuclear magnetic resonance) spectra were analyzed. The remarkable down-field...

Analysis of cocondensation of melamine and urea through formaldehyde with carbon 13 nuclear magnetic resonance spectroscopy

Treesearch

Bunichiro Tomita; Chung-Yun Hse

1995-01-01

The 13C-NMR (carbon 13 nuclear magnetic resonance) spectra of urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins, and melamine-urea-formaldehyde (MUF) cocondensed resins synthesized under various conditions were taken with a frequency of 75 MHz. The main purpose was to investigate whether or not the occurrences of cocondensation...

Research of propagation the high frequency signals during total solar eclipses

NASA Astrophysics Data System (ADS)

Ryabova, Mariya; Ivanov, Vladimir; Ivanov, Dmitrii; Riabova, Natalia; Elsukov, Aleksei

Vertical-oblique sounding methods are special importance for the study; they provide data on the electron concentration. In panoramic sounders, the mean frequencies of sounding signals vary consequently in the range of apriori uncertainty of the conditions of their reflection from the ionosphere. The aim of this work is the experimental study of the variations in the MUFs along one-hop HF lines during the total solar eclipses, and their application for the estimation of the effective recombination coefficient. To solve the above problem, experiments were carried out with the use of a chirp sounder manufactured at the Volga State University of Technology. The main advantages of chirp sounder are connected with the use of continuous chirps, which allow for the use of methods of optimal reception when deciphering in a frequency region, which provides for a signal-to-noise ratio acceptable for obtaining reliable results. We carried out experiments on oblique chirp sounding of the ionosphere during the total solar eclipse of March 29, 2006, and on the reference days of March 28 and 30, 2006, as well as during the total solar eclipse of August 1, 2008, and the reference days of July 31 and August 2, 2008. The ionosonde transmitters were located in Great Britain (the town of Inskip), Cyprus, and Irkutsk, and the receiver was located in Yoshkar-Ola. The maximal phases of the eclipse of March 29 at the target sounding point (TSP) were 0.89 for Cyprus-Yoshkar-Ola (observed at 11:15 UT) and 0.49 for Inskip-Yoshkar-Ola (observed at 11:03 UT); for the eclipse of August 1, 1 for Irkutsk-Yoshkar-Ola (observed at 11:36 UT). Based on the primary data (ionograms), the secondary data were determined in automatic mode. In particular, diurnal variations in the MUF of the 1F2 and 2F2 modes were calculated for the eclipse periods and the reference days along different radio paths. Variation in the MUF on the reference days required the use of a smoothing procedure, which was carried out using the IRI international ionospheric model. Based on the obtained data on the profile of the electron concentration for the TSP along a path, ionograms of oblique sounding were synthesized. This allowed for model adaptations and, as a result, smoothed diurnal variations in the MUF for the reference days, as well as for an estimation of the difference frequencies. The data obtained allows for the estimation of the effective recombination coefficient in the ionospheric F layer with the use of the ionospheric balance equation. Calculations have shown that the effective recombination coefficient of the ionospheric F region increases by 24% at an increase in the maximum eclipse phase from 0.49 to 1.0. The authors gratefully acknowledge financial support from the Russian Foundation for Basic Research (grants 13-07-00371-a, 13-02-00524-a, 13-07-97041).

Bombardment of Thin Lithium Films with Energetic Plasma Flows

ERIC Educational Resources Information Center

Gray, Travis Kelly

2009-01-01

The Divertor Erosion and Vapor Shielding Experiment (DEVEX) has been constructed in the Center for Plasma-Material Interactions at the University of Illinois at Urbana-Champaign. It consists of a conical theta-pinch connected to a 60 kV, 36 [mu]F capacitor bank which is switched with a rise time of 3.5 [mu]s. This results in a peak current of 300…

Changes of Linearity in MF2 Index with R12 and Solar Activity Maximum

NASA Astrophysics Data System (ADS)

Villanueva, L.

2013-05-01

Critical frequency of F2 layer is related to the solar activity, and the sunspot number has been the standard index for ionospheric prediction programs. This layer, being considered the most important in HF radio communications due to its highest electron density, determines the maximum frequency coming back from ground base transmitter signals, and shows irregular variation in time and space. Nowadays the spatial variation, better understood due to the availability of TEC measurements, let Space Weather Centers have observations almost in real time. However, it is still the most difficult layer to predict in time. Short time variations are improved in IRI model, but long term predictions are only related to the well-known CCIR and URSI coefficients and Solar activity R12 predictions, (or ionospheric indexes in regional models). The concept of the "saturation" of the ionosphere is based on data observations around 3 solar cycles before 1970, (NBS, 1968). There is a linear relationship among MUF (0Km) and R12, for smooth Sunspot numbers R12 less than 100, but constant for higher R12, so, no rise of MUF is expected for R12 higher than 100. This recommendation has been used in most of the known Ionospheric prediction programs for HF Radio communication. In this work, observations of smoothed ionospheric index MF2 related to R12 are presented to find common features of the linear relationship, which is found to persist in different ranges of R12 depending on the specific maximum level of each solar cycle. In the analysis of individual solar cycles, the lapse of linearity is less than 100 for a low solar cycle and higher than 100 for a high solar cycle. To improve ionospheric predictions we can establish levels for solar cycle maximum sunspot numbers R12 around low 100, medium 150 and high 200 and specify the ranges of linearity of MUF(0Km) related to R12 which is not only 100 as assumed for all the solar cycles. For lower levels of solar cycle, discussions of present observations are presented.

Dual protection of wood surface treated with melamine-modified urea-formaldehyde resin mixed with ammonium polyphosphate against both fire and decay

Treesearch

Xing-xia Ma; Grant T. Kirker; Ming-liang Jiang; Yu-zhang Wu

2016-01-01

Surface coatings of melamine-modified urea-formaldehyde resins (MUFs) containing ammonium polyphosphate (APP) have been shown to significantly improve the fire retardancy of wood by prolonging the ignition time and reducing the heat release rate, total heat released, and mass loss rate. Dual protection of wood against both decay and fire has been proposed for remedial...

Improved liquid chromatography-MS/MS of heparan sulfate oligosaccharides via chip-based pulsed makeup flow.

PubMed

Huang, Yu; Shi, Xiaofeng; Yu, Xiang; Leymarie, Nancy; Staples, Gregory O; Yin, Hongfeng; Killeen, Kevin; Zaia, Joseph

2011-11-01

Microfluidic chip-based hydrophilic interaction chromatography (HILIC) is a useful separation system for liquid chromatography-mass spectrometry (LC-MS) in compositional profiling of heparan sulfate (HS) oligosaccharides; however, ions observed using HILIC LC-MS are low in charge. Tandem MS of HS oligosaccharide ions with low charge results in undesirable losses of SO(3) from precursor ions during collision induced dissociation. One solution is to add metal cations to stabilize sulfate groups. Another is to add a nonvolatile, polar compound such as sulfolane, a molecule known to supercharge proteins, to produce a similar effect for oligosaccharides. We demonstrate use of a novel pulsed makeup flow (MUF) HPLC-chip. The chip enables controlled application of additives during specified chromatographic time windows and thus minimizes the extent to which nonvolatile additives build up in the ion source. The pulsed MUF system was applied to LC-MS/MS of HS oligosaccharides. Metal cations and sulfolane were tested as additives. The most promising results were obtained for sulfolane, for which supercharging of the oligosaccharide ions increased their signal strengths relative to controls. Tandem MS of these supercharged precursor ions showed decreased abundances of product ions from sulfate losses yet more abundant product ions from backbone cleavages.

Enhanced Ionization Of Propellant Through Carbon Nanotube Growth On Angled Walls

DTIC Science & Technology

2017-06-01

FEEP field emission electric propulsion MUF mass utilization factor NSTAR NASA Solar Technology Application Readiness SCATHA Spacecraft Charging at...Experiments This experiment, Spacecraft Charging at High Altitudes (SCATHA), was developed by the U.S. Air Force along with NASA [5]. A satellite was launched...propulsion system, gimbal mounted and deployed on DS1. Source: [6]. 3. DAWN A more recent use of XIPS is the DAWN Spacecraft from NASA . Orbiting the

Improved Maneuver Criteria Evaluation Program

DTIC Science & Technology

1979-11-01

If the rotor rpm breakpoint (OMGBL2) is le :-s than the mininum rotor rpm (OMEGMN), then the rpm bleed :ate (OMGBDI) will be the only bleed rate used...VCP =60 PSU 1 EEF = 1 OMGBD1=2 OMGBD3=0 OMGRC2=0 VERR = 2 MPRINT= 1 OMEGMN=300 OMGBL.2=4 OMGBL4=0 OMGRD2=0 MUF = 1 BINERT:2860 TRPMMN= 0 OMGBD2=0 OMGBD4...height is within 2 feet of the measured height. These comparisons show that the MCEP maneuvers are accurate for simulating these types of maneuvers

Behaviour and occurrence of estrogens in municipal sewage treatment plants--II. Aerobic batch experiments with activated sludge.

PubMed

Ternes, T A; Kreckel, P; Mueller, J

1999-01-12

Aerobic batch experiments containing a diluted slurry of activated sludge from a real sewage treatment plant (STP) near Frankfurt/Main were undertaken, in order to investigate the persistence of natural estrogens and contraceptives under aerobic conditions. The batch experiments showed that while in contact with activated sludge the natural estrogen 17 beta-estradiol was oxidized to estrone, which was further eliminated in the batch experiments in an approximate linear time dependence. Further degradation products of estrone were not observed. 16 alpha-hydroxyestrone was rapidly eliminated, again without detection of further degradation products. The contraceptive 17 alpha-ethinylestradiol was principally persistent under the selected aerobic conditions, whereas mestranol was rapidly eliminated and small portions of 17 alpha-ethinylestradiol were formed by demethylation. Additionally, two glucuronides of 17 beta-estradiol (17 beta-estradiol-17-glucuronide and 17 beta-estradiol-3-glucuronide) were cleaved in contact with the diluted activated sludge solution and thus 17 beta-estradiol was released. The glucuronidase activity of the activated sludge was further confirmed by the cleavage of 4-methylumbelliferyl-beta-D-glucuronide (MUF-beta-glucuronide) in a solution of a activated sludge slurry and Milli-Q-water (1:100, v/v). The turnover rate obtained was approximately steady state, with a turnover rate of 0.1 mumol/l for the released MUF. Hence, it is very likely that the glucuronic acid moiety of 17 beta-estradiol glucuronides and other estrogen glucuronides become cleaved in a real municipal STP, so that the concentrations of the free estrogens increase.

Analysis of Environmental Assessment Procedures during OTH Emulator Test Flights

DTIC Science & Technology

1987-11-01

NUMER 2 GOVT ACCESSION NO. 3. RECIPIENT’S CATALOG NUMBER AFGL-TR-87-0333 4. TITLE (A d SubtStle) 5. TYPE OF REPORT & PERIOD COVERF 0 ANALYSIS OF...Discrepancies between MUFF1 and MOFFI values were resolved by ray tracing through a realistic ionosphere (derived from the Argentia ionograms) and...28~ Api 197 FlMd u~4 1 1 ULL U LL. LL. LL LA.. M : D 048r 00) Ir- CLI- a- OW C)o: LL1 C, LiW D D El i gurw lb MUF dnd MC’ \\ 28 April 1987 F2-Mode 5 0

Palm top plasma focus device as a portable pulsed neutron source

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

Rout, R. K.; Niranjan, Ram; Srivastava, R.

2013-06-15

Development of a palm top plasma focus device generating (5.2 {+-} 0.8) Multiplication-Sign 10{sup 4} neutrons/pulse into 4{pi} steradians with a pulse width of 15 {+-} 3 ns is reported for the first time. The weight of the system is less than 1.5 kg. The system comprises a compact capacitor bank, a triggered open air spark gap switch, and a sealed type miniature plasma focus tube. The setup is around 14 cm in diameter and 12.5 cm in length. The energy driver for the unit is a capacitor bank of four cylindrical commercially available electrolytic capacitors. Each capacitor is ofmore » 2 {mu}F capacity, 4.5 cm in diameter, and 9.8 cm in length. The cost of each capacitor is less than US$ 10. The internal diameter and the effective length of the plasma focus unit are 2.9 cm and 5 cm, respectively. A DC to DC converter power supply powered by two rechargeable batteries charges the capacitor bank to the desired voltage and also provides a trigger pulse of -15 kV to the spark gap. The maximum energy of operation of the device is 100 J (8 {mu}F, 5 kV, 59 kA) with deuterium gas filling pressure of 3 mbar. The neutrons have also been produced at energy as low as 36 J (3 kV) of operation. The neutron diagnostics are carried out with a bank of {sup 3}He detectors and with a plastic scintillator detector. The device is portable, reusable, and can be operated for multiple shots with a single gas filling.« less

The International Symposium on Microwave Signatures and Remote Sensing Held in Gothenburg (Sweden) on 19-22 January 1987.

DTIC Science & Technology

1987-05-28

7 A-A1 I 334 NT NAI A SNI JN O ICR MUfI CM NTU AN III UNCLASSIF ED Rkl~ lWLA 2MY90 LAF/C 17/9 ML u-iD i1.0 V , .2 2 il4 016 - 9 I or 9P: FILE OM...returned radar signal to sea various mathematical models. The group state it has been found that the scatter- studied these spikes in an attempt to...Sobieski (Univer- object. A mathematical model relating sity of Louvain, Belgium) attempted to these parameters was developed but no develop an

Automatic interpretation of oblique ionograms

NASA Astrophysics Data System (ADS)

Ippolito, Alessandro; Scotto, Carlo; Francis, Matthew; Settimi, Alessandro; Cesaroni, Claudio

2015-03-01

We present an algorithm for the identification of trace characteristics of oblique ionograms allowing determination of the Maximum Usable Frequency (MUF) for communication between the transmitter and receiver. The algorithm automatically detects and rejects poor quality ionograms. We performed an exploratory test of the algorithm using data from a campaign of oblique soundings between Rome, Italy (41.90 N, 12.48 E) and Chania, Greece (35.51 N, 24.01 E) and also between Kalkarindji, Australia (17.43 S, 130.81 E) and Culgoora, Australia (30.30 S, 149.55 E). The success of these tests demonstrates the applicability of the method to ionograms recorded by different ionosondes in various helio and geophysical conditions.

Evaluated teletherapy source library

DOEpatents

Cox, Lawrence J.; Schach Von Wittenau, Alexis E.

2000-01-01

The Evaluated Teletherapy Source Library (ETSL) is a system of hardware and software that provides for maintenance of a library of useful phase space descriptions (PSDs) of teletherapy sources used in radiation therapy for cancer treatment. The PSDs are designed to be used by PEREGRINE, the all-particle Monte Carlo dose calculation system. ETSL also stores other relevant information such as monitor unit factors (MUFs) for use with the PSDs, results of PEREGRINE calculations using the PSDs, clinical calibration measurements, and geometry descriptions sufficient for calculational purposes. Not all of this information is directly needed by PEREGRINE. It also is capable of acting as a repository for the Monte Carlo simulation history files from which the generic PSDs are derived.

Infant-mortality testing of high-energy-density capacitors used on Nova

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

Merritt, B.T.; Whitham, K.

1983-01-01

Nova is a solid-state large laser for inertial-confinement fusion research. Its flashlamps are driven by a 60-MJ capacitor bank. Part of this bank is being built with high-energy-density capacitors, 52-..mu..F, 22 kV, 12.5 kJ. A total of 2645 of these capacitors have been purchased from two manufacturers. Each capacitor was infant-mortality tested. The first test consisted of a high-potential test, bushing-to-case, since these capacitors have dual bushings. Then the capacitors were discharged 500 times with circuit conditions approximating the capacitors normal flashlamp load. Failure of either of these tests or if the capacitor was leaking was cause for rejection.

Ship Motions Prediction Applications Manager. Predict. User’s Manual

DTIC Science & Technology

1994-02-01

OMEGAE ..2 IF (.10T. LAT) GO T0 6 3 CONTINUE DO 4 Iml. 3 IDXt2oI DO 6 31l. 3 JDX=2.3 721 I L.EQO I! TL’IIJ () 0(.0.)IF (L.GT. TL~ . 3 ::fT3D(L) IF...L.LT.O) TL( IJ)ufl(J,I) 6CONTINUE 4 CONTINUE TL 13 TLl. )-VTL (11 II* OMEGAE )TL 2,3 *T , 3 ) -V*T (2 1)/ II*OMFGAE, TL 3 ,uh3) +VTL (1:1j1t Ie,(G T 2aL 3 ...INTEGER NVK,NMU.YOMEGA,NSIGMA.NSIGWH,NTM0O,NRANG,NNMUl(S) REAL VK(8),MUf(37,8), OMEGA (30),SIGMA(10) S1G’P;H(4),TMODAT ( 3 ), 2

OGUPSA sensor scheduling architecture and algorithm

NASA Astrophysics Data System (ADS)

Zhang, Zhixiong; Hintz, Kenneth J.

1996-06-01

This paper introduces a new architecture for a sensor measurement scheduler as well as a dynamic sensor scheduling algorithm called the on-line, greedy, urgency-driven, preemptive scheduling algorithm (OGUPSA). OGUPSA incorporates a preemptive mechanism which uses three policies, (1) most-urgent-first (MUF), (2) earliest- completed-first (ECF), and (3) least-versatile-first (LVF). The three policies are used successively to dynamically allocate and schedule and distribute a set of arriving tasks among a set of sensors. OGUPSA also can detect the failure of a task to meet a deadline as well as generate an optimal schedule in the sense of minimum makespan for a group of tasks with the same priorities. A side benefit is OGUPSA's ability to improve dynamic load balance among all sensors while being a polynomial time algorithm. Results of a simulation are presented for a simple sensor system.

Molded underfill (MUF) encapsulation for flip-chip package: A numerical investigation

NASA Astrophysics Data System (ADS)

Azmi, M. A.; Abdullah, M. K.; Abdullah, M. Z.; Ariff, Z. M.; Saad, Abdullah Aziz; Hamid, M. F.; Ismail, M. A.

2017-07-01

This paper presents the numerical simulation of epoxy molding compound (EMC) filling in multi flip-chip packages during encapsulation process. The empty and a group flip chip packages were considered in the mold cavity in order to study the flow profile of the EMC. SOLIDWORKS software was used for three-dimensional modeling and it was incorporated into fluid analysis software namely as ANSYS FLUENT. The volume of fluid (VOF) technique was used for capturing the flow front profiles and Power Law model was applied for its rheology model. The numerical result are compared and discussed with previous experimental and it was shown a good conformity for model validation. The prediction of flow front was observed and analyzed at different filling time. The possibility and visual of void formation in the package is captured and the number of flip-chip is one factor that contributed to the void formation.

Transequatorial Propagation and Depletion Precursors

NASA Astrophysics Data System (ADS)

Miller, E. S.; Bust, G. S.; Kaeppler, S. R.; Frissell, N. A.; Paxton, L. J.

2014-12-01

The bottomside equatorial ionosphere in the afternoon and evening sector frequently evolves rapidly from smoothly stratified to violently unstable with large wedges of depleted plasma growing through to the topside on timescales of a few tens of minutes. These depletions have numerous practical impacts on radio propagation, including amplitude scintillation, field-aligned irregularity scatter, HF blackouts, and long-distance transequatorial propagation at frequencies above the MUF. Practical impacts notwithstanding, the pathways and conditions under which depletions form remain a topic of vigorous inquiry some 80 years after their first report. Structuring of the pre-sunset ionosphere---morphology of the equatorial anomalies and long-wavelength undulations of the isodensity contours on the bottomside---are likely to hold some clues to conditions that are conducive to depletion formation. The Conjugate Depletion Experiment is an upcoming transequatorial forward-scatter HF/VHF experiment to investigate pre-sunset undulations and their connection with depletion formation. We will present initial results from the Conjugate Depletion Experiment, as well as a companion analysis of a massive HF propagation data set.

The application of real-time model update by oblique ionospheric sounders to frequency sharing

NASA Astrophysics Data System (ADS)

Uffelman, D. R.; Harnish, L. O.; Goodman, J. M.

1983-03-01

Frequency management systems for the high frequencies (HF) currently in use by the US Department of Defense (DoD) rely heavily on manual selection of frequencies which were allocated on a circuit by circuit basis. There is no capability to anticipate frequency changes (QSY's) in advance in a manner such that a frequency being released by one user is utilized effectively and immediately by a second user. A scheme by which a small computer model of the maximum usage frequency (MUF) of the HF channel (MINIMUF 3.5) is made to perform very accurately to anticipate channel characteristics in a short term prediction mode was examined. It is proposed that this model be utilized to provide automated frequency management which would allow one to anticipate frequency availability and thereby sharing of frequencies between several users. Utilizing data obtained from an oblique sounder net on the East Coast of the United States, the manner in which this might be accomplished is demonstrated.

Effect of anode shape on correlation of neutron emission with pinch energy for a 2.7 kJ Mather-type plasma focus device

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

Hussain, S. S.; Murtaza, Ghulam; Zakaullah, M.

Correlation of neutron emission with pinch energy for a Mather-type plasma focus energized by a single capacitor 12.5 muF, 21 kV (2.7 kJ) is investigated by employing time resolved and time integrated detectors for two different anode shapes. The maximum average neutron yield of about 1.3x10{sup 8} per shot is recorded with cylindrical anode, that increases to 1.6x10{sup 8} per shot for tapered anode. At optimum pressure the input energy converted to pinch energy is about 24% for cylindrical anode as compared to 36% for tapered anode. It is found that the tapered anode enhances neutron flux about 25+-5% bothmore » in axial and radial directions and also broadens the pressure range for neutron emission as well as pinch energy. The neutron yield and optimum gas filling pressures are found strongly dependent on the anode shape.« less

Ion Beam Measurements of a Dense Plasma Focus Device Using CR 39 Nuclear Track Detectors

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

Ngoi, S. K.; Yap, S. L.; Wong, C. S.

The project is carried out using a small Mather type plasma focus device powered by a 15 kV, 30 {mu}F capacitor. The filling gas used is argon. The ion beam generated is investigated by both time resolved and time integrated methods. Investigation on the dynamic of the current sheath is also carried out in order to obtain an optimum condition for ion beam production. The angular distribution of the ion emission is measured at positions of 0 deg. (end-on), 45 deg. and 90 deg. (side-on) by using CR-39 nuclear track detectors. The divergence of the ion beam is also determinedmore » using these detectors. A biased ion collector is used for time resolved measurement of the ion beam. Time of flight technique is employed for the determination of the ion beam energy. Average ion beam energy obtained is about 180 keV. The ion beam produced can be used for applications such as material surface modification and ion implantation.« less

Preliminary Results Of A 600 Joules Small Plasma Focus Device

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

Lee, S. H.; Yap, S. L.; Wong, C. S.

Preliminary results of a 600 J (3.7 muF, 18 kV) Mather type plasma focus device operated at low pressure will be presented. The discharge is formed between a solid anode with length of 6 cm and six symmetrically and coaxially arranged cathode rods of same lengths. The cathode base is profiled in a knife-edge design and a set of coaxial plasma gun are attached to it in order to initiate the breakdown and enhance the current sheath formation. The experiments have been performed in argon gas under a low pressure condition of several microbars. The discharge current and the voltagemore » across the electrodes during the discharge are measured with high voltage probe and current coil. The current and voltage characteristics are used to determine the possible range of operating pressure that gives good focusing action. At a narrow pressure regime of 9.0+-0.5 mubar, focusing action is observed with good reproducibility. Preliminary result of ion beam energy is presented. More work will be carried out to investigate the radiation output.« less

Spatial distribution of enzyme driven reactions at micro-scales

NASA Astrophysics Data System (ADS)

Kandeler, Ellen; Boeddinghaus, Runa; Nassal, Dinah; Preusser, Sebastian; Marhan, Sven; Poll, Christian

2017-04-01

Studies of microbial biogeography can often provide key insights into the physiologies, environmental tolerances, and ecological strategies of soil microorganisms that dominate in natural environments. In comparison with aquatic systems, soils are particularly heterogeneous. Soil heterogeneity results from the interaction of a hierarchical series of interrelated variables that fluctuate at many different spatial and temporal scales. Whereas spatial dependence of chemical and physical soil properties is well known at scales ranging from decimetres to several hundred metres, the spatial structure of soil enzymes is less clear. Previous work has primarily focused on spatial heterogeneity at a single analytical scale using the distribution of individual cells, specific types of organisms or collective parameters such as bacterial abundance or total microbial biomass. There are fewer studies that have considered variations in community function and soil enzyme activities. This presentation will give an overview about recent studies focusing on spatial pattern of different soil enzymes in the terrestrial environment. Whereas zymography allows the visualization of enzyme pattern in the close vicinity of roots, micro-sampling strategies followed by MUF analyses clarify micro-scale pattern of enzymes associated to specific microhabitats (micro-aggregates, organo-mineral complexes, subsoil compartments).

Performance of a 10 kV, 625 kA, 85 kJ energy discharge module utilizing a solid dielectric switch

NASA Astrophysics Data System (ADS)

Richardson, R. A.; Cravey, W. R.; Goerz, D. A.

We have designed and tested an 87-kJ energy discharge system consisting of two 720-(mu)F, 11-kV capacitors discharged through parallel coaxial cables into a 250 nH load. Data will be presented on the current and voltage waveforms, with calculated values of the system inductance and resistance. The bank uses a solid dielectric switch punctured by an explosive bridge wire (EBW) to initiate the discharge. With the capacitors charged to 9 kV, a 625-kA peak current is sent through the load with a ringing frequency of 6.8 kHz. The coaxial cables used to transmit the current to the load are 3 m in length. Both RG-217 and YK-198 cable types were tested, which have an inductance of 74 nH/ft and 35 nH/ft respectively. Normal operation requires that each cable carry 52 kA. The cables were tested to 100 kA each by connecting fewer cables to the load, and gradually increasing the charge voltage. The solid dielectric switch was chosen for high reliability. Details of the switch will be describes and data on its performance will be presented.

Low voltage operation of plasma focus.

PubMed

Shukla, Rohit; Sharma, S K; Banerjee, P; Das, R; Deb, P; Prabahar, T; Das, B K; Adhikary, B; Shyam, A

2010-08-01

Plasma foci of compact sizes and operating with low energies (from tens of joules to few hundred joules) have found application in recent years and have attracted plasma-physics scientists and engineers for research in this direction. We are presenting a low energy and miniature plasma focus which operates from a capacitor bank of 8.4 muF capacity, charged at 4.2-4.3 kV and delivering approximately 52 kA peak current at approximately 60 nH calculated circuit inductance. The total circuit inductance includes the plasma focus inductance. The reported plasma focus operates at the lowest voltage among all reported plasma foci so far. Moreover the cost of capacitor bank used for plasma focus is nearly 20 U.S. dollars making it very cheap. At low voltage operation of plasma focus, the initial breakdown mechanism becomes important for operation of plasma focus. The quartz glass tube is used as insulator and breakdown initiation is done on its surface. The total energy of the plasma focus is approximately 75 J. The plasma focus system is made compact and the switching of capacitor bank energy is done by manual operating switch. The focus is operated with hydrogen and deuterium filled at 1-2 mbar.

Development of a solar-powered infrared injection laser microminiature transmitting system

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

Falter, D.D.; Alley, G.T.; Falter, K.G.

1989-01-01

A solar-powered infrared microminiature transmitting system is being developed to provide scientists with a tool to continuously track and study Africanized bees. Present tracking methods have limited ranges and lack the capability of continuously tracking individual insects. Preliminary field tests of a stationary prototypic transmitter have demonstrated a range of 1.1 km. The basic design consists of an array of nine 1-mm{sup 2} solar cells, which collect energy for storage in a 1.0-{mu}F tantalum chip capacitor. When the capacitor has been charged to a sufficient level, the circuitry that monitors the capacitor voltage level wakes up'' and fires a 5-{mu}smore » pulse through an 840-nm GaAlAs injection laser diode. The process is then repeated, making the signal frequency (which ranges from 50 to 300 Hz) dependent on solar luminance. The solar cells, capacitor, and laser diode are mounted in hybrid microcircuit fashion directly on the silicon substrate containing the CMOS control and driver circuitry. The transmitter measures {approximately}4 {times} 6 mm and weighs {approximately}65 mg. The receiving system is based on an 8-in. telescope and a Si PIN diode detector. 8 refs., 10 figs.« less

Application of small-size antennas for estimation of angles of arrival of HF signals scattered by ionospheric irregularities

NASA Astrophysics Data System (ADS)

Guo, Qiang; Galushko, Volodymyr G.; Zalizovski, Andriy V.; Kashcheyev, Sergiy B.; Zheng, Yu

2018-05-01

A modification of the Doppler Interferometry Technique is suggested to enable estimating angles of arrival of comparatively broadband HF signals scattered by random irregularities of the ionospheric plasma with the use of small-size weakly directional antennas. The technique is based on the measurements of cross-spectra phases of the probe radiation recorded at least in three spatially separated points. The developed algorithm has been used to investigate the angular and frequency-time characteristics of HF signals propagating at frequencies above the maximum usable one (MUF) for the direct radio path Moscow-Kharkiv. The received signal spectra show presence of three families of spatial components attributed, respectively, to scattering by plasma irregularities near the middle point of the radio path, ground backscatter signals and scattering of the sounding signals by the intense plasma turbulence associated with auroral activations. It has been shown that the regions responsible for the formation of the third family components are located well inside the auroral oval. The drift velocity and direction of the auroral ionosphere plasma have been determined. The obtained estimates are consistent with the classical conception of the ionospheric plasma convection at high latitudes and do not contradict the results of investigations of the auroral ionosphere dynamics using the SuperDARN network.

Dynamics, Control, and Fabrication of Micro Embedded Heaters and Sensors for Micro SMA Active Endoscopes

NASA Astrophysics Data System (ADS)

Aphanuphong, Sutha

This research investigates design and control of an active catheter for minimally invasive medical procedures. Microfabrication techniques are developed and several prototypes were constructed. The understanding and analysis results from each design iteration are utilized to improve the overall design and the performance of each revision. An innovative co-fabrication method is explored to simplify the fabrication process and also improve the quality, repeatability, and reliability of the active catheter. This co-fabrication method enables a unique compact integrated heater and sensor film to be directly constructed on a shape memory alloy (SMA) sheet and to be utilized as an outline mask to pattern a micro SMA actuator. There are two functions integrated in the sensor film: heat sources to actuate the micro SMA actuator and sensors to provide temperature and strain of the active catheter to closed-loop control algorithms. Three main aspects are explored in this dissertation: thermal dynamics in the MicroFlex (muF) film and its effect on the sensor capabilities; non-minimum phase behavior and its effect on control performance, and film micro fabrication design and its effect on thermal dynamics. The sensor film developed from this understanding is able to deliver excellent heating and sensing performance with a simple design.

Bacterial Chitin Hydrolysis in Two Lakes with Contrasting Trophic Statuses

PubMed Central

Carstens, Dörte; Keller, Esther; Vazquez, Francisco; Schubert, Carsten J.; Zeyer, Josef; Bürgmann, Helmut

2012-01-01

Chitin, which is a biopolymer of the amino sugar glucosamine (GlcN), is highly abundant in aquatic ecosystems, and its degradation is assigned a key role in the recycling of carbon and nitrogen. In order to study the significance of chitin decomposition in two temperate freshwater lakes with contrasting trophic and redox conditions, we measured the turnover rate of the chitin analog methylumbelliferyl-N,N′-diacetylchitobioside (MUF-DC) and the presence of chitinase (chiA) genes in zooplankton, water, and sediment samples. In contrast to the eutrophic and partially anoxic lake, chiA gene fragments were detectable throughout the oligotrophic water column and chiA copy numbers per ml of water were up to 15 times higher than in the eutrophic waters. For both lakes, the highest chiA abundance was found in the euphotic zone—the main habitat of zooplankton, but also the site of production of easily degradable algal chitin. The bulk of chitinase activity was measured in zooplankton samples and the sediments, where recalcitrant chitin is deposited. Both, chiA abundance and chitinase activity correlated well with organic carbon, nitrogen, and concentrations of particulate GlcN. Our findings show that chitin, although its overall contribution to the total organic carbon is small (∼0.01 to 0.1%), constitutes an important microbial growth substrate in these temperate freshwater lakes, particularly where other easily degradable carbon sources are scarce. PMID:22101058

Correction of congenital heart defects in Jehovah's Witness children.

PubMed

Alexi-Meskishvili, V; Stiller, B; Koster, A; Böttcher, W; Hübler, M; Photiadis, J; Lange, P E; Hetzer, R

2004-06-01

Between August 1989 and July 2003 14 Jehovah's Witness children with congenital heart defects (CHD) aged under 14 years (median 2.9 years) and with a median weight of 14 kg underwent 16 operations with cardiopulmonary bypass (CPB). Five children had been operated on previously between one to three times. Preoperatively, 7 children were prepared with oral iron supplementation and 10 received erythropoietin. Mean hemoglobin (Hb) at admission was 14.4 g/dl (range 10.9 - 19.2). The cardiopulmonary bypass (CPB) circuit was modified to reduce total priming volume. High doses of aprotinin were administered. The modified ultrafiltration (MUF) circuit, used in 7 patients, was parallel to the ECC circuit with continuous circulation of the blood through a small shunt between the arterial and venous lines. Operations performed consisted of VSD closure (3 pts.), ASD closure (3 pts.), Fontan operation (2 pts.), and complete AV canal correction, aortic commissurotomy, Ross operation, Glenn shunt, cor triatriatum correction, MV reconstruction combined with left outflow tract stenosis resection, correction of absent pulmonary valve syndrome, and correction of tetralogy of Fallot in one patient each. There were no deaths. Mean duration of CPB was 192 min and mean aortic cross-clamp time 40 min. The Hb value at the end of the operation was 4.9 - 14.5 g/dl (mean 9.6) and at discharge it was 7.1 - 14.5 g/dl (mean 15.5). No blood or blood products were used in any patient. Bloodless cardiac surgery with and without CPB can be safely performed in Jehovah's Witness infants and children.

First results of mapping sporadic E with a passive observing network

NASA Astrophysics Data System (ADS)

Rice, D. D.; Sojka, J. J.; Eccles, J. V.; Raitt, J. W.; Brady, J. J.; Hunsucker, R. D.

2011-12-01

Sporadic E (Es) can have dramatic effects on communications in the HF and low VHF range, producing over-the-horizon propagation for signals normally restricted to line-of-sight, and sometimes blocking F region propagation of signals in the lower HF range. Measuring the E region winds believed to produce Es is difficult, and no practical means of predicting Es occurrence currently exists other than statistical models. We describe a low-cost observing network based on software-controlled receivers that continuously watches for Es in near-real time using oblique HF propagation from existing transmitters. Results from an 11-day pilot campaign in July 2008 demonstrated that even a limited number of receivers in the network can readily determine the presence and extent of Es patches. These observations indicate that Es often develops quickly over regions of several hundred kilometers rather than gradually drifting across an area. These widespread Es “blooms” have been observed near winter solstice and occasionally at other times of the year; their lifetime depends on the season but can be several hours during the summer. The current network allows the extent of Es in portions of North America to be evaluated: the geographical distribution of Es and bounds on the density of the layer are inferred from its effects on the ionospheric maximum usable frequency (MUF). This study demonstrates quantitatively that Es mapping can provide information about Es layer geographical growth and decay. The observed sudden widespread Es blooms are space weather events that can have significant impact on HF/lower VHF communications and propagation model predictions.

New insight on the formation of whey protein microbeads by a microfluidic system

NASA Astrophysics Data System (ADS)

Andoyo, Robi; Guyomarc'h, Fanny; Tabuteau, Hervé; Famelart, Marie-Hélène

2018-02-01

The current paper describes the formation of whey protein microbeads (WPM) having a spherical shape and a monodispersed size distribution. A microfluidic flow-focusing geometry was used to control the production of whey protein microdroplets in a hydrophobic phase. The microfluidic system consists of two inlet channels where the WPI solution and the lipophilic phase were separately injected towards the flow-focusing (FF) junction where they eventually meet, then co-flow. A whey protein isolate (WPI) solution of 150 g/kg protein and two types of hydrophobic phases, i.e. sunflower oil and n-dodecane, were tested as the continuous phase. The formation of WPM was observed microscopically. The aim of the present study was to describe the production of stable monodisperse WPM in suspension in milk ultrafiltrate using a microfluidic system. Hints to perform the control of the running parameters, i.e. choice of the hydrophobic phase or fluids flowrates, are provided. The results showed that in the sunflower oil, microdroplets had a large polydisperse size distribution, while in n-dodecane, microdroplets with narrow size distribution were obtained. Stabilization of the whey protein microdroplets through heat-gelation at 75 °C for 20 min in n-dodecane produced WPM and no change in shape nor size is observed. Meanwhile replacing the n-dodecane by MUF using centrifugation and washing caused the swelling of the WPM, but dispersity remained low. From this study, microfluidic system seemed to be a suitable method to be used for producing small quantities of monodisperse WPM.

The effects of tetracaine on charge movement in fast twitch rat skeletal muscle fibres.

PubMed

Hollingworth, S; Marshall, M W; Robson, E

1990-02-01

1. The effects of tetracaine, a local anaesthetic that inhibits muscle contraction, on membrane potential and intramembrane charge movements were investigated in fast twitch rat muscle fibres (extensor digitorum longus). 2. The resting membrane potentials of surface fibres from muscles bathed in isotonic Ringer solution containing 2 mM-tetracaine were well maintained, but higher concentrations of tetracaine caused a time-dependent fall of potential. Muscle fibres bathed in hypertonic solutions containing 2 mM-tetracaine were rapidly depolarized. In both isotonic and hypertonic solutions, the depolarizing effect of tetracaine could not be reversed. 3. Charge movement measurements were made using the middle-of-the-fibre voltage clamp technique. The voltage dependence of charge movements measured in cold isotonic solutions was well fitted by a Boltzmann distribution (Q(V) = Qmax/(1 + exp(-(V-V)/k] where Qmax = 37.3 +/- 2.8 nC muF-1, V = -17.9 +/- 1.2 mV and k = 12.6 +/- 0.8 mV (n = 6, 2 degrees C; means +/- S.E. of means). Similar values were obtained when 2 mM-tetracaine was added to the isotonic bathing fluid (Qmax = 40.6 +/- 2.3 nC microF-1, V = -14.1 +/- 1.3 mV, k = 15.3 +/- 0.8 mV; n = 8, 2 degrees C). 4. Charge movements measured around mechanical threshold in muscle fibres bathed in hypertonic solutions were reduced when 2 mM-tetracaine was added to the bathing fluid. The tetracaine-sensitive component of charge was well fitted with an unconstrained Boltzmann distribution which gave: Qmax = 7.5 nC microF-1, V = -46.5 mV, k = 5.5 mV. The e-fold rise of the foot of the curve was 9.3 mV.

The effects of tetracaine on charge movement in fast twitch rat skeletal muscle fibres.

PubMed Central

Hollingworth, S; Marshall, M W; Robson, E

1990-01-01

1. The effects of tetracaine, a local anaesthetic that inhibits muscle contraction, on membrane potential and intramembrane charge movements were investigated in fast twitch rat muscle fibres (extensor digitorum longus). 2. The resting membrane potentials of surface fibres from muscles bathed in isotonic Ringer solution containing 2 mM-tetracaine were well maintained, but higher concentrations of tetracaine caused a time-dependent fall of potential. Muscle fibres bathed in hypertonic solutions containing 2 mM-tetracaine were rapidly depolarized. In both isotonic and hypertonic solutions, the depolarizing effect of tetracaine could not be reversed. 3. Charge movement measurements were made using the middle-of-the-fibre voltage clamp technique. The voltage dependence of charge movements measured in cold isotonic solutions was well fitted by a Boltzmann distribution (Q(V) = Qmax/(1 + exp(-(V-V)/k] where Qmax = 37.3 +/- 2.8 nC muF-1, V = -17.9 +/- 1.2 mV and k = 12.6 +/- 0.8 mV (n = 6, 2 degrees C; means +/- S.E. of means). Similar values were obtained when 2 mM-tetracaine was added to the isotonic bathing fluid (Qmax = 40.6 +/- 2.3 nC microF-1, V = -14.1 +/- 1.3 mV, k = 15.3 +/- 0.8 mV; n = 8, 2 degrees C). 4. Charge movements measured around mechanical threshold in muscle fibres bathed in hypertonic solutions were reduced when 2 mM-tetracaine was added to the bathing fluid. The tetracaine-sensitive component of charge was well fitted with an unconstrained Boltzmann distribution which gave: Qmax = 7.5 nC microF-1, V = -46.5 mV, k = 5.5 mV. The e-fold rise of the foot of the curve was 9.3 mV. PMID:2348406

Investigation of the Ionsopheric Response to Tropical Cyclones Using Ground and Satellite Based Observations Over Indian Region

NASA Astrophysics Data System (ADS)

G J, B.; Lal, M.

2015-12-01

The present work investigates the equatorial ionospheric response to tropical cyclones which were observed over the Arabian and Bay of Bengal Ocean during the year 2009-2013. The present study utilizes various datasets in order to strengthen the mechanism of troposphere-ionosphere coupling. The tropical cyclone track and data can be obtained from the Indian Meteorological Department, New Delhi. Ionsopheric variations can be monitored from the ground based digisonde located at equatorial station, Trivandrum (8.48oN, 76.95oE), Tirunelveli (8.7oN, 77.8oE) and off equatorial station Allahabad (25.45oN, 81.85oE) and CDAAC COSMIC satellite data. It is believed that tropical cyclone induced convection as the driving agent for the increased gravity wave activity in the lower atmosphere. The convective regions are identified with the help of Outgoing Long wave radiation from NOAA. Gravity wave propagation is mainly depends on the background wind condition, can be examined by using NASA MERRA reanalyses. These Upward propagating gravity waves deposit their energy and momentum into the upper atmosphere as Travelling Ionospheric Disturbances (TIDs). It is found that the enhancement of this wave activity is increased by orders of 10 at ionospheric level. The Ionospheric variability is measured by examining the variation in the parameters such as, Total Electron Content (TEC), foF2, hmF2, foE, MUF, h'E and h'F. The extensive analysis will be carried out in order to understand the coupling mechanism between troposphere and ionosphere region. The detailed results will be discussed in the meeting.

Intracellular studies of hair cells in the mammalian cochlea.

PubMed Central

Russell, I J; Sellick, P M

1978-01-01

1. Intracellular recordings were made from inner hair cells in the first turn of the guinea-pig cochlea, the recording sites being confirmed by the injection of Procion yellow dye and subsequent histology. 2. The receptor potential, in response to a pure tone burst, consisted of an AC response which followed the wave form of the stimulus and was analogous to the extracellularly recorded cochlear microphonic and a depolarizating DC response which followed the envelope of the tone burst and was analogous to the extracellularly recorded summating potential. 3. The DC response was broadly tuned at high sound pressure having a maximal amplitude of 27 mV at a sound pressure level of ca. 100 db; however the bandwidth of the response was reduced at lower sound pressure level. Isoamplitude curves for the DC response were indistinguishable from the threshold curves for auditory nerve fibres. 4. The AC response was tuned in a similar fashion to the DC response except that it was attenuated at 6-9 db/octave with respect to the DC response. It is suggested that this difference was due to the effect of membrane capacitance and resistance on the AC response. In contrast the extracellularly recorded AC component was not subject to this attenuation. 5. The total resistance and capacitance in three cells were found to be 46-61 Momega and 7.8-15.8 muF respectively. 6. Intracellular resistance changes were measured during sound stimulation, the resistance change being proportional to the DC receptor potential, indicating constant current flow through the hair cell. The current varied between 0.37 and 0.81 nA between cells. The time constant for seven cells was found to lie between 0.31 and 0.76 msec. 7. A map of the basilar membrane showing position of hair cells against characteristic frequency corresponded to the cut-off frequencies of the basilar membrane mechanical measurements and the innervation sites of spiral ganglion cells. PMID:731538

Validation of High Frequency (HF) Propagation Prediction Models in the Arctic region

NASA Astrophysics Data System (ADS)

Athieno, R.; Jayachandran, P. T.

2014-12-01

Despite the emergence of modern techniques for long distance communication, Ionospheric communication in the high frequency (HF) band (3-30 MHz) remains significant to both civilian and military users. However, the efficient use of the ever-varying ionosphere as a propagation medium is dependent on the reliability of ionospheric and HF propagation prediction models. Most available models are empirical implying that data collection has to be sufficiently large to provide good intended results. The models we present were developed with little data from the high latitudes which necessitates their validation. This paper presents the validation of three long term High Frequency (HF) propagation prediction models over a path within the Arctic region. Measurements of the Maximum Usable Frequency for a 3000 km range (MUF (3000) F2) for Resolute, Canada (74.75° N, 265.00° E), are obtained from hand-scaled ionograms generated by the Canadian Advanced Digital Ionosonde (CADI). The observations have been compared with predictions obtained from the Ionospheric Communication Enhanced Profile Analysis Program (ICEPAC), Voice of America Coverage Analysis Program (VOACAP) and International Telecommunication Union Recommendation 533 (ITU-REC533) for 2009, 2011, 2012 and 2013. A statistical analysis shows that the monthly predictions seem to reproduce the general features of the observations throughout the year though it is more evident in the winter and equinox months. Both predictions and observations show a diurnal and seasonal variation. The analysed models did not show large differences in their performances. However, there are noticeable differences across seasons for the entire period analysed: REC533 gives a better performance in winter months while VOACAP has a better performance for both equinox and summer months. VOACAP gives a better performance in the daily predictions compared to ICEPAC though, in general, the monthly predictions seem to agree more with the observations compared to the daily predictions.

Colonization of overlaying water by bacteria from dry river sediments.

PubMed

Fazi, Stefano; Amalfitano, Stefano; Piccini, Claudia; Zoppini, Annamaria; Puddu, Alberto; Pernthaler, Jakob

2008-10-01

We studied the diversity, community composition and activity of the primary microbial colonizers of the water above freshly re-wetted sediments from a temporary river. Dried sediments, collected from Mulargia River (Sardinia, Italy), were covered with sterile freshwater in triplicate microcosms, and changes of the planktonic microbial assemblage were monitored over a 48 h period. During the first 9 h bacterial abundance was low (1.5 x 10(4) cells ml(-1)); it increased to 3.4 x 10(6) cells ml(-1) after 28 h and did not change thereafter. Approximately 20% of bacteria exhibited DNA de novo synthesis already after 9 h of incubation. Changes of the ratios of (3)H-leucine to (3)H-thymidine incorporation rates indicated a shift of growth patterns during the experiment. Extracellular enzyme activity showed a maximum at 48 h with aminopeptidase activity (430.8 +/- 22.6 nmol MCA l(-1) h(-1)) significantly higher than alkaline phosphatase (98.6 +/- 4.3 nmol MUF l(-1) h(-1)). The primary microbial colonizers of the overlaying water - as determined by 16S rRNA gene sequence analysis - were related to at least six different phylogenetic lineages of Bacilli and to Alphaproteobacteria (Brevundimonas spp. and Caulobacter spp.). Large bacterial cells affiliated to one clade of Bacillus sp. were rare in the dried sediments, but constituted the majority of the planktonic microbial assemblage and of cells with detectable DNA-synthesis until 28 h after re-wetting. Their community contribution decreased in parallel with a rise of flagellated and ciliated protists. Estimates based on cell production rates suggested that the rapidly enriched Bacillus sp. suffered disproportionally high loss rates from selective predation, thus favouring the establishment of a more heterogenic assemblage of microbes (consisting of Proteobacteria, Actinobacteria and Cytophaga-Flavobacteria). Our results suggest that the primary microbial colonizers of the water above dried sediments are passively released into the plankton and that their high growth potential is counteracted by the activity of bacterivorous protists.

Integrated Process Monitoring based on Systems of Sensors for Enhanced Nuclear Safeguards Sensitivity and Robustness

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

Humberto E. Garcia

This paper illustrates safeguards benefits that process monitoring (PM) can have as a diversion deterrent and as a complementary safeguards measure to nuclear material accountancy (NMA). In order to infer the possible existence of proliferation-driven activities, the objective of NMA-based methods is often to statistically evaluate materials unaccounted for (MUF) computed by solving a given mass balance equation related to a material balance area (MBA) at every material balance period (MBP), a particular objective for a PM-based approach may be to statistically infer and evaluate anomalies unaccounted for (AUF) that may have occurred within a MBP. Although possibly being indicativemore » of proliferation-driven activities, the detection and tracking of anomaly patterns is not trivial because some executed events may be unobservable or unreliably observed as others. The proposed similarity between NMA- and PM-based approaches is important as performance metrics utilized for evaluating NMA-based methods, such as detection probability (DP) and false alarm probability (FAP), can also be applied for assessing PM-based safeguards solutions. To this end, AUF count estimates can be translated into significant quantity (SQ) equivalents that may have been diverted within a given MBP. A diversion alarm is reported if this mass estimate is greater than or equal to the selected value for alarm level (AL), appropriately chosen to optimize DP and FAP based on the particular characteristics of the monitored MBA, the sensors utilized, and the data processing method employed for integrating and analyzing collected measurements. To illustrate the application of the proposed PM approach, a protracted diversion of Pu in a waste stream was selected based on incomplete fuel dissolution in a dissolver unit operation, as this diversion scenario is considered to be problematic for detection using NMA-based methods alone. Results demonstrate benefits of conducting PM under a system-centric strategy that utilizes data collected from a system of sensors and that effectively exploits known characterizations of sensors and facility operations in order to significantly improve anomaly detection, reduce false alarm, and enhance assessment robustness under unreliable partial sensor information.« less

Input related microbial carbon dynamic of soil organic matter in particle size fractions

NASA Astrophysics Data System (ADS)

Gude, A.; Kandeler, E.; Gleixner, G.

2012-04-01

This paper investigated the flow of carbon into different groups of soil microorganisms isolated from different particle size fractions. Two agricultural sites of contrasting organic matter input were compared. Both soils had been submitted to vegetation change from C3 (Rye/Wheat) to C4 (Maize) plants, 25 and 45 years ago. Soil carbon was separated into one fast-degrading particulate organic matter fraction (POM) and one slow-degrading organo-mineral fraction (OMF). The structure of the soil microbial community were investigated using phospholipid fatty acids (PLFA), and turnover of single PLFAs was calculated from the changes in their 13C content. Soil enzyme activities involved in the degradation of carbohydrates was determined using fluorogenic MUF (methyl-umbelliferryl phosphate) substrates. We found that fresh organic matter input drives soil organic matter dynamic. Higher annual input of fresh organic matter resulted in a higher amount of fungal biomass in the POM-fraction and shorter mean residence times. Fungal activity therefore seems essential for the decomposition and incorporation of organic matter input into the soil. As a consequence, limited litter input changed especially the fungal community favouring arbuscular mycorrhizal fungi. Altogether, supply and availability of fresh plant carbon changed the distribution of microbial biomass, the microbial community structure and enzyme activities and resulted in different priming of soil organic matter. Most interestingly we found that only at low input the OMF fraction had significantly higher calculated MRT for Gram-positive and Gram-negative bacteria suggesting high recycling of soil carbon or the use of other carbon sources. But on average all microbial groups had nearly similar carbon uptake rates in all fractions and both soils, which contrasted the turnover times of bulk carbon. Hereby the microbial carbon turnover was always faster than the soil organic carbon turnover and higher carbon input reduced the carbon storage efficiency from 51 % in the low input to 20 %. These findings suggest that microbial community preferentially assimilated fresh carbon sources but also used recycled existing soil carbon. However, the priming rate was drastically reduced under carbon limitation. In consequence at high carbon availability more carbon was respired to activate the existing soil carbon (priming) whereas at low carbon availability new soil carbon was formed at higher efficiencies.

Viewpoints on impacts of climate change on soil quality

NASA Astrophysics Data System (ADS)

Dilly, Oliver; Pfeiffer, Eva-Maria; Trasar-Cepeda, Carmen; Nannipieri, Paolo

2010-05-01

Climate projections indicate a critical increase in temperature and modification of the precipitation pattern for the next century worldwide (IPCC 2007). Higher temperature increase are expected in polar than in temperate and tropical regions. In addition, studies on the response of microbial metabolism to temperature changes showed lower sensitivity at higher temperature level as analyzed by Q10 values (Kirschbaum 1995). The temperature response as indicated by the Q10 value refers to physiological response including enzyme configuration and substrate availability. For soils from an undisturbed forest site in eastern Amazonia, Knorr et al. (2005) observed even that the apparent pool turnover times are insensitive to temperature and received evidence that non-labile soil organic carbon was more sensitive to temperature than labile soil organic carbon. Linking the climate projections and the findings related to Q10 values suggests that the microbial activity may be stimulated to a higher degree at northern latitudes than at lower latitudes. But few studies address the role of temperature changes on soil organic matter pool and microbial biomass and activities although temperature changes may be important (Dilly et al. 2003). On top, the thawing of permafrost soil (24 % of exposed land in the Northern Hemisphere) represents a further threat since erosion processes will occur and captured gases may evolve to the atmosphere. Finally, dryness and drying-rewetting cycling that are affected by climate change are regulating soil organic carbon turnover (Mamilov and Dilly 2001). The lecture will summarize basic findings and positive feedback on our climate system and also address the concept of ‘soil energ-omics' including the interaction between respiration and microbial colonization and the respective metabolic quotient (Dilly 2006). Key words: Q10, Nitrogen deposition, Permafrost, Carbon turnover, Microbial biomass, adjustment References Dilly, O., 2006. Evaluating soil quality in ecosystems based on modern respiratory approaches. In: Cenci R., Sena F. (eds.) Biodiversity-bioindication to evaluate soil health. European Commission EUR 22245EN, p. 59-64 Dilly O., Blume H.-P., Munch J.C., 2003. Soil microbial activities in Luvisols and Anthrosols during 9 years of region-typical tillage and fertilisation practices in northern Germany. Biogeochemistry 65, 319-339 IPPC 2007. The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (eds Solomon, S. et al.) (Cambridge University Press, 2007). Kirschbaum, M.U.F., 1995. The temperature dependence of soil organic matter decomposition, and the effect of global warming on soil organic C storage. Soil Biology and Biochemistry 27, 753-760 Knorr W., Prentice I.C., House J.I., Holland E.A. 2005. Long-term sensitivity of soil carbon to warming. Nature 433, 298-301 Mamilov, A. Sh., Dilly, O., 2002. Soil microbial eco-physiology as affected by short-term variations in environmental conditions. Soil Biology and Biochemistry 34, 1283-1290

Ionic currents in the guinea-pig taenia coli.

PubMed Central

Inomata, H; Kao, C Y

1976-01-01

Short segments of portions of taenia coli of the guinea-pig averaging 54 mum X 219 mum X ca. 200 mum have been studied by a double sucrose-gap voltage-clamp technique. 2. The average total capacitance was 0-4 muF, corresponding to approximately 10(4) cells, if a specific membrane capacitance of 3 muF/cm2 were assumed. 3. A significant resistance, averaging 11-4omega, was in series with the membrane, and seriously limited the accuracy of the voltage control possible. 4. On depolarization, an early transient inward current was followed by a late maintained outwary current. 5. The late current was carried mainly by K+, because its direction could be reversed if the preparation were first depolarized in isotonic K2SO4 and held back to the original resting potential. 6. After appropriate corrections for residual capacitative and leakage currents, a reversal potential for the late current (Eb) was determined to be 15-20 mV more negative than the natural resting potential. It was not affected by the amplitude or the duration of the activating voltage step, but could be changed by prolonged applications of holding current. 7. At rest, the ratio of PNa:PK was 0-16:1; for Eb it was 0-05:1. 8. The reversal potential for the transient early inward current (Ea) averaged 22 mV in Krebs-bicarbonate solution, but was shifted to about 35 mV when the late current was first suppressed with tetraethylammonium ion. The shift suggested that there was some overlap of the early and late currents. 9. Reduction of [Na+]o to 50% of normal, or replacement of all Na+ with dimethyldiethanol ammonium ion and choline ion, failed to cause any significant shifts in the reversal potential of the early current or reduce the magnitude of the early current. 10. Reduction of [Ca2+]o to 0-25 or 0-1 of the normal caused shifts of the Ea toward the negative and reductions in the early current. These changes can occur without changes in the maximum chord conductance of the early current, such as might happen in ordinary Krebs-bicarbonate solution, or in preparations which had been depolarized by prior treatment with isotonic K2SO4 and then held back to the original membrane voltage. 11. Increase of [Ca2+]o to 5 times normal increased the early inward current, and the maximum chord conductances of the early and late currents, but did not shift the Ea. 12. In preparations pretreated with TEA, increasing [Ca2+]o to 5 times normal shifted Ea toward 45 mV. 13. The various observations are interpreted to mean that the early current in the taenia coli is carried principally by influx of Ca2+, and not by Na+. PMID:1255524

Formation of marine snow and enhanced enzymatic activities in oil-contaminated seawater

NASA Astrophysics Data System (ADS)

Ziervogel, K.; McKay, L.; Yang, T.; Rhodes, B.; Nigro, L.; Gutierrez, T.; Teske, A.; Arnosti, C.

2010-12-01

The fate of oil spilled into the ocean depends on its composition, as well as on biological, chemical, and physical characteristics of the spill site. We investigated the effects of oil addition from the Deepwater Horizon (DH) spill on otherwise uncontaminated water collected close to the spill site. Incubation on a roller table mimicked the physical dynamics of natural seawater, leading to the formation of marine snow-oil aggregates. We measured the enzymatic activities of heterotrophic microbes associated with the aggregates and in the surrounding water, and assessed microbial population and community composition as oil-marine snow aggregates formed and aged in the water. Surface seawater taken near the spill site in May 2010 that had no visible crude oil was incubated in 1-l glass bottles with (oil-bottles) and without (no-oil bottles) a seawater-oil mixture collected from the same site. In the oil-bottles formation of brownish, densely packed marine snow (2-3 cm diameter) was observed within the first hour of the roller table incubation. In contrast no-oil bottles showed aggregate formation only after 3 days, and aggregates were almost transparent, less abundant, and smaller in size (< 1cm diameter). Subsamples of the water surrounding the aggregates were taken throughout 21 days of the roller table incubation, and analyzed for bacterial abundance and community structure as well as the activities of hydrolytic enzymes that are used by heterotrophic bacteria to degrade organic matter. We monitored oil-degrading activities with MUF-stearate and -butyrate, and also measured b-glucosidase, alkaline phosphatase, aminopeptidase, and six different polysaccharide hydrolase activities. Enzymatic activities were up to one order of magnitude higher in the oil-bottles compared with the no-oil bottles throughout the entire incubation time. Butyrate hydrolysis was elevated throughout the time course of the incubation, and stearate hydrolysis was particularly high over the initial 10 days. Activities of enzymes not directly associated with metabolism of oil were also enhanced, however, particularly b-glucosidase, leucine aminopeptidase, and two of the polysaccharide hydrolase activities. These enhanced activities may be a reflection of increased overall microbial metabolism and growth in the oil-bottles, as demonstrated by the 4-fold increase in suspended bacterial cell numbers in oil-bottles over the course of the incubation. Suspended cell numbers in no-oil bottles remained almost unchanged throughout the incubation time. Moreover, aggregates from the oil-bottles were densely colonized by highly active bacteria (5 x 10^9 cells ml-1), one order of magnitude greater than for no-oil aggregates, and two orders of magnitude greater than in the surrounding water. Comparisons of microbial community composition of the oil-bottles and no-oil bottles as well as of the aggregates are currently in progress. Aggregates observed in seawater at the DH spill site likely transport highly active microbial communities to the deeper waters, where they facilitate degradation of deepwater oil.

An electrostatic CMOS/BiCMOS Lithium ion vibration-based harvester-charger IC

NASA Astrophysics Data System (ADS)

Torres, Erick Omar

Self-powered microsystems, such as wireless transceiver microsensors, appeal to an expanding application space in monitoring, control, and diagnosis for commercial, industrial, military, space, and biomedical products. As these devices continue to shrink, their microscale dimensions allow them to be unobtrusive and economical, with the potential to operate from typically unreachable environments and, in wireless network applications, deploy numerous distributed sensing nodes simultaneously. Extended operational life, however, is difficult to achieve since their limited volume space constrains the stored energy available, even with state-of-the-art technologies, such as thin-film lithium-ion batteries (Li Ion) and micro-fuel cells. Harvesting ambient energy overcomes this deficit by continually replenishing the energy reservoir and, as a result, indefinitely extending system lifetime. In this work, an electrostatic harvester that harnesses ambient kinetic energy from vibrations to charge an energy-storage device (e.g., a battery) is investigated, developed, and evaluated. The proposed harvester charges and holds the voltage across a vibration-sensitive variable capacitor so that vibrations can induce it to generate current into the battery when capacitance decreases (as its plates separate). The challenge is that energy is harnessed at relatively slow rates, producing low output power, and the electronics required to transfer it to charge a battery can easily demand more than the power produced. To this end, the system reduces losses by time-managing and biasing its circuits to operate only when needed and with just enough energy while charging the capacitor through an efficient quasi-lossless inductor-based precharger. As result, the proposed energy harvester stores a net energy gain in the battery during every vibration cycle. Two energy-harvesting integrated circuits (IC) were analyzed, designed, developed, and validated using a 0.7-im BiCMOS process and a 30-Hz mechanical variable capacitor. The precharger, harvester, monitoring, and control microelectronics of the first prototype draw sufficient power to operate and at the same time produce experimentally 1.27, 2.14, and 2.87 nJ per vibration cycle for battery voltages at 2.7, 3.5, and 4.2 V, which with 30-Hz vibrations produce 38.1, 64.2, and 86.1 nW. By incorporating into the system a self-tuning loop that adapts optimally the inductor-based precharger to varying battery voltages, the second prototype harnessed and gained 1.93, 2.43, and 3.89 nJ per vibration cycle at battery voltages 2.7, 3.5, and 4.2 V, generating 57.89, 73.02, and 116.55 nW at 30 Hz. The harvester ultimately charges from 2.7 to 4.2 V a 1-muF capacitor (which emulates a small thin-film Li Ion) in approximately 69 s, harnessing in the same length of time 47.9% more energy than with a non-adapting harvester.

Polymorphic toxin systems: Comprehensive characterization of trafficking modes, processing, mechanisms of action, immunity and ecology using comparative genomics

PubMed Central

2012-01-01

Background Proteinaceous toxins are observed across all levels of inter-organismal and intra-genomic conflicts. These include recently discovered prokaryotic polymorphic toxin systems implicated in intra-specific conflicts. They are characterized by a remarkable diversity of C-terminal toxin domains generated by recombination with standalone toxin-coding cassettes. Prior analysis revealed a striking diversity of nuclease and deaminase domains among the toxin modules. We systematically investigated polymorphic toxin systems using comparative genomics, sequence and structure analysis. Results Polymorphic toxin systems are distributed across all major bacterial lineages and are delivered by at least eight distinct secretory systems. In addition to type-II, these include type-V, VI, VII (ESX), and the poorly characterized “Photorhabdus virulence cassettes (PVC)”, PrsW-dependent and MuF phage-capsid-like systems. We present evidence that trafficking of these toxins is often accompanied by autoproteolytic processing catalyzed by HINT, ZU5, PrsW, caspase-like, papain-like, and a novel metallopeptidase associated with the PVC system. We identified over 150 distinct toxin domains in these systems. These span an extraordinary catalytic spectrum to include 23 distinct clades of peptidases, numerous previously unrecognized versions of nucleases and deaminases, ADP-ribosyltransferases, ADP ribosyl cyclases, RelA/SpoT-like nucleotidyltransferases, glycosyltranferases and other enzymes predicted to modify lipids and carbohydrates, and a pore-forming toxin domain. Several of these toxin domains are shared with host-directed effectors of pathogenic bacteria. Over 90 families of immunity proteins might neutralize anywhere between a single to at least 27 distinct types of toxin domains. In some organisms multiple tandem immunity genes or immunity protein domains are organized into polyimmunity loci or polyimmunity proteins. Gene-neighborhood-analysis of polymorphic toxin systems predicts the presence of novel trafficking-related components, and also the organizational logic that allows toxin diversification through recombination. Domain architecture and protein-length analysis revealed that these toxins might be deployed as secreted factors, through directed injection, or via inter-cellular contact facilitated by filamentous structures formed by RHS/YD, filamentous hemagglutinin and other repeats. Phyletic pattern and life-style analysis indicate that polymorphic toxins and polyimmunity loci participate in cooperative behavior and facultative ‘cheating’ in several ecosystems such as the human oral cavity and soil. Multiple domains from these systems have also been repeatedly transferred to eukaryotes and their viruses, such as the nucleo-cytoplasmic large DNA viruses. Conclusions Along with a comprehensive inventory of toxins and immunity proteins, we present several testable predictions regarding active sites and catalytic mechanisms of toxins, their processing and trafficking and their role in intra-specific and inter-specific interactions between bacteria. These systems provide insights regarding the emergence of key systems at different points in eukaryotic evolution, such as ADP ribosylation, interaction of myosin VI with cargo proteins, mediation of apoptosis, hyphal heteroincompatibility, hedgehog signaling, arthropod toxins, cell-cell interaction molecules like teneurins and different signaling messengers. Reviewers This article was reviewed by AM, FE and IZ. PMID:22731697

Development of high energy density electrical double layer capacitors

NASA Astrophysics Data System (ADS)

Devarajan, Thamarai selvi

Electrochemical Double Layer capacitors (EDLCs) have shown themselves as a viable energy storage alternative. EDLCs have high power density, faster charge/discharge, wide operating temperature and long cycle life compared to batteries since it stores charge by physical separation. Despites all their advantages, their low energy density stand as a bottleneck for capacitors. This research aims to increase the energy density of EDLC without compromising the power density. Energy is proportional to the square of cell voltage. Cell voltage is mainly dependent on electrolyte breakdown. Electrolytes also provide ions for charge separation and conduction. Therefore various electrolytes (Solutes and Solvents) which can give high concentration, solubility and decomposition potential were characterized in the first part of the research. In that study, a novel ionic liquid OPBF4 had higher capacitance and comparable voltage window compared to commercial TEABF4 in Acetonitrile. However, the increased polarity of the fixed ring O-atom and the ion-ion interaction in OPBF4 was responsible for lowering its conductivity. Oxygenated ionic compounds with alkyl groups had lower stability due to beta elimination between two electron withdrawing atoms. Volume based thermodynamics and quantum chemical calculations were used to calculate ion size, HOMO/LUMO energies, and free energy changes and establish relationship with capacitance, redox potential and melting points respectively. In addition free energy of fusion was used to predict the melting point. Ion size had correlation with capacitance due to compact double layer formation. Free energy changes did not explain the differences in melting point and predicted dielectric constant was inconsistent with the polarity. This is presumably due to using Van der Waals volume instead of crystal structure volume and insufficient incorporation of polarization term. The HOMO/LUMO energies gave direct relation between oxidation and reduction potential at 1mA/cm 2. A brief study on non-polar co-solvents for EDLC was studied. Among the solvents studied, fluorinated solvents had low melting point and viscosity due to incorporation of asymmetry. However, because of low dielectric constant, TEABF4 is insoluble and had to be mixed with other solvents. The mixed fluorinated solvents had slightly higher voltage window due to decreased donicity of lone pairs of electrons. The second approach to increasing energy density is to increase capacitance. Capacitance is mainly dependent on surface area and porosity of electrodes. Nanostructured materials which can offer multiple charge storage are currently of interest. Hence, novel NiSi nanotubes were studied as electrodes for supercapacitor applications. Silicon material has high capacity and these inert electrodes can enable higher capacitance by controlling the porosity and functional groups in specific electrolytes. The Silicon wafers were made porous by anodization using hydrofluoric acid. In order to improve the conductivity, the porous silicon was doped, then plated with Ni using electroless plating method and annealed to form nickel mono silicide. Gold was deposited on the back side of the electrode to enhance conductivity. Our porous NiSi electrodes gave capacitance of about 1185muF /cm2 in 0.5 M H 2SO4. Further investigation of oxide formation and modification of functional groups will help achieve higher capacitance.

The Upgraded European Digital Upper Atmosphere Server: new DIAS products for the high latitude ionosphere, the topside ionosphere and the plasmasphere

NASA Astrophysics Data System (ADS)

Belehaki, Anna; Kutiev, Ivan; Zolesi, Bruno; Tsagouri, Ioanna; Dialetis, Dimitris; Marinov, Pencho; Fidanova, Stefka; Cander, Lili; Pietrella, Marco; Tziotziou, Kostas; Lykiardopoulos, Angelos

2013-04-01

Knowledge of the state of the upper atmosphere, and in particular its ionized part, is very important in several applications affected by space weather, especially the communications and navigation systems that rely on radio transmission. To better classify the ionosphere and forecast its disturbances over Europe, a data and model infrastructure platform called the European Digital Upper Atmosphere Server (DIAS) has been established in the National Observatory of Athens by a European consortium formed around eight ionospheric stations, and funded by the European Commission. The DIAS system operates since 2006 and the basic products that are delivered are real-time and historical ionograms, frequency plots and maps of the ionosphere on the foF2, M(3000)F2, MUF and bottomside electron density, as well as long term and short term forecasting up to 24 hour ahead. The DIAS system supports more than 500 subscribed users, including telecommunication companies, satellite operators, space agencies, radio amateurs, research organizations and the space weather scientific community. In 2012 the system has been upgraded, in close collaboration between the National Observatory of Athens, the Istituto Nazionale di Geofisica e Vulcanologia and the Bulgarian Academy of Sciences, with funding from the ESA/SSA Programme. The first group of new products results from the implementation of the TaD model (Topside Sounder Model assisted by Digisonde) that makes possible the generation of maps of the electron density at heights up to GNSS orbits, and of TEC and partial TEC maps (topside and plasmaspheric) over Europe. The TaD is based on the simple empirical functions for the transition height, the topside electron density scale height and their ratio, based on the Alouette/ISIS database, and models separately the oxygen, hydrogen and helium ions density profiles. The model takes as input the plasma characteristics at the height of maximum electron concentration that are provided in real-time by the DIAS Digisondes. To further improve its accuracy, we adjust the modeled TEC parameter with the GNSS-TEC parameter calculated at the Digisondes location. This adjustment forces the model to correctly reproduce the topside scale height, even in cases when the scale height at hmF2 is not available. This adjustment is very important for the application of TaD in an operational environment. The second group of new products consists of long term prediction and of nowcasting maps of the foF2 parameter that cover the whole European region - including Scandinavia. Long term prediction maps have been extended to 80 deg N applying the CCIR coefficients for the region above 65 deg N, while from 32 to 60 deg N we continue to apply SIRM (Simplified Ionospheric Regional Model), as in the case of middle latitude maps that are released routinely by the DIAS system. Between 60 and 65 deg N there is a buffer zone where an interpolation routine is applied. Nowcasting maps are based on the SIRMUP (SIRM updated in real-time) concept, however, a different effective sunspot number (Reff) is estimated for each latitudinal zone, from which a synthetic Reff is calculated.

A Real-Time Assimilative Model for IRI

NASA Astrophysics Data System (ADS)

Reinisch, B. W.; Huang, X.; Galkin, I.; Bilitza, D.

2012-04-01

Ionospheric models are mostly unable to correctly predict the effects of space weather events and atmospheric disturbances on the ionosphere. This is especially true for the International Reference Ionosphere (IRI) which by design is a monthly median (climatological) model [Bilitza et al., 2011]. We propose a Real-Time Assimilative Model "RTAM" for IRI that is ingesting, initially, the available real-time Digisonde GIRO [Reinisch and Galkin, 2011] data streams: foF2/hmF2, MUF3000F2, foF1/hmF1, and foE/hmF2 [Galkin et al., 2011]. Deviations of these characteristics, especially foF2, from the monthly median values are the main cause for errors in the IRI model prediction. The assimilative modeling will provide a high-resolution, global picture of the ionospheric response to various short-term events observed during periods of storm activity or the impact of gravity waves coupling the ionosphere to the lower atmosphere, including timelines of the vertical restructuring of the plasma distribution. GIRO currently provides reliable real-time data from 42 stations at a cadence of 15 min or 5 min. The number of stations is rapidly growing and is likely to soon be complemented by satellite borne topside sounders. IRI uses the characteristics predictions based on CCIR/URSI maps of coefficients. The diurnal variation of the foF2 characteristic, for example, is presented by the Fourier series Σ6 foF 2(T, φ,λ,χ) = a0(φ,λ,χ)+ (an(φ,λ,χ)cosnT + bn(φ,λ,χ)sin nT), n=1 where T is Universal Time in hours, and φ, λ, χ are the geographic latitude, longitude, and modified dip latitude, respectively. The coefficients an are in turn expanded as functions φ, λ, χ resulting in a set of 24 global maps of 988 coefficients each, one for each month of the year and for two levels of solar activity, R12=10 and 100, where R12 is the 12-month running-mean of the monthly sunspot number Rm (2*12*988 = 23,712 coefficients in all) [ITU-R, 2011]. For a given point in time, 988 coefficients need to be adjusted such that the new foF2 map reproduces the 42 values measured at that time by the GIRO network and smoothly transforms the original model map. This totally underdetermined task has been approached by using the mathematical tool of Linear Programming; preliminary results are presented. The technique can also be applied for regional modeling. Retroactive RTAM processing of the maps for an entire solar cycle will result in improved CCIR and URSI maps of the F2 peak characteristics, i.e., in an improved IRI electron density model. Bilitza D., L.-A. McKinnell, B. Reinisch, and T. Fuller-Rowell (2011), The International Reference Ionosphere (IRI) today and in the future, J. Geodesy, 85:909-920, DOI 10.1007/s00190-010-0427-x Galkin, I. A., B. W. Reinisch, , X. Huang, and D. Bilitza, Assimilation of GIRO data in Real-Time IRI: Progress Report, International Reference Ionosphere Workshop IRI-2011, Hermanus, South Africa, October 10-14, 2011. ITU-R, Information Document on Ionospheric Mapping, Working Party 3L (3L/80 Ann. 4, 3L/86. 3L/95), Oct. 2011. Reinisch, B. W. and I. A. Galkin (2011), Global Ionospheric Radio Observatory (GIRO), Earth, Planets and Space, 63(4), 377-381.

Development of a methodology to evaluate material accountability in pyroprocess

NASA Astrophysics Data System (ADS)

Woo, Seungmin

This study investigates the effect of the non-uniform nuclide composition in spent fuel on material accountancy in the pyroprocess. High-fidelity depletion simulations are performed using the Monte Carlo code SERPENT in order to determine nuclide composition as a function of axial and radial position within fuel rods and assemblies, and burnup. For improved accuracy, the simulations use short burnups step (25 days or less), Xe-equilibrium treatment (to avoid oscillations over burnup steps), axial moderator temperature distribution, and 30 axial meshes. Analytical solutions of the simplified depletion equations are built to understand the axial non-uniformity of nuclide composition in spent fuel. The cosine shape of axial neutron flux distribution dominates the axial non-uniformity of the nuclide composition. Combined cross sections and time also generate axial non-uniformity, as the exponential term in the analytical solution consists of the neutron flux, cross section and time. The axial concentration distribution for a nuclide having the small cross section gets steeper than that for another nuclide having the great cross section because the axial flux is weighted by the cross section in the exponential term in the analytical solution. Similarly, the non-uniformity becomes flatter as increasing burnup, because the time term in the exponential increases. Based on the developed numerical recipes and decoupling of the results between the axial distributions and the predetermined representative radial distributions by matching the axial height, the axial and radial composition distributions for representative spent nuclear fuel assemblies, the Type-0, -1, and -2 assemblies after 1, 2, and 3 depletion cycles, is obtained. These data are appropriately modified to depict processing for materials in the head-end process of pyroprocess that is chopping, voloxidation and granulation. The expectation and standard deviation of the Pu-to-244Cm-ratio by the single granule sampling calculated by the central limit theorem and the Geary-Hinkley transformation. Then, the uncertainty propagation through the key-pyroprocess is conducted to analyze the Material Unaccounted For (MUF), which is a random variable defined as a receipt minus a shipment of a process, in the system. The random variable, LOPu, is defined for evaluating the non-detection probability at each Key Measurement Point (KMP) as the original Pu mass minus the Pu mass after a missing scenario. A number of assemblies for the LOPu to be 8 kg is considered in this calculation. The probability of detection for the 8 kg LOPu is evaluated with respect the size of granule and powder using the event tree analysis and the hypothesis testing method. We can observe there are possible cases showing the probability of detection for the 8 kg LOPu less than 95%. In order to enhance the detection rate, a new Material Balance Area (MBA) model is defined for the key-pyroprocess. The probabilities of detection for all spent fuel types based on the new MBA model are greater than 99%. Furthermore, it is observed that the probability of detection significantly increases by increasing granule sample sizes to evaluate the Pu-to-244Cm-ratio before the key-pyroprocess. Based on these observations, even though the Pu material accountability in pyroprocess is affected by the non-uniformity of nuclide composition when the Pu-to-244Cm-ratio method is being applied, that is surmounted by decreasing the uncertainty of measured ratio by increasing sample sizes and modifying the MBAs and KMPs. (Abstract shortened by ProQuest.).

Development of high energy pulsed plasma simulator for plasma-lithium trench experiment

NASA Astrophysics Data System (ADS)

Jung, Soonwook

To simulate detrimental events in a tokamak and provide a test-stand for a liquid lithium infused trench (LiMIT) device, a pulsed plasma source utilizing a theta pinch in conjunction with a coaxial plasma accelerator has been developed. An overall objective of the project is to develop a compact device that can produce 100 MW/m2 to 1 GW/m2 of plasma heat flux (a typical heat flux level in a major fusion device) in ~ 100 mus (≤ 0.1 MJ/m2) for a liquid lithium plasma facing component research. The existing theta pinch device, DEVeX, was built and operated for study on lithium vapor shielding effect. However, a typical plasma energy of 3 - 4 kJ/m2 is too low to study an interaction of plasma and plasma facing components in fusion devices. No or little preionized plasma, ringing of magnetic field, collisions of high energy particles with background gas have been reported as the main issues. Therefore, DEVeX is reconfigured to mitigate these issues. The new device is mainly composed of a plasma gun for a preionization source, a theta pinch for heating, and guiding magnets for a better plasma transportation. Each component will be driven by capacitor banks and controlled by high voltage / current switches. Several diagnostics including triple Langmuir probe, calorimeter, optical emission measurement, Rogowski coil, flux loop, and fast ionization gauge are used to characterize the new device. A coaxial plasma gun is manufactured and installed in the previous theta pinch chamber. The plasma gun is equipped with 500 uF capacitor and a gas puff valve. The increase of the plasma velocity with the plasma gun capacitor voltage is consistent with the theoretical predictions and the velocity is located between the snowplow model and the weak - coupling limit. Plasma energies measured with the calorimeter ranges from 0.02 - 0.065 MJ/m2 and increases with the voltage at the capacitor bank. A cross-check between the plasma energy measured with the calorimeter and the triple probe / optics shows that the plasma energies are in agreement with each other. The effect of theta pinch on preionized plasma has been investigated when operated in conjunction with the coaxial plasma gun. The previous theta coil (1 turn, 40 nH) is connected with 72 muF capacitor bank to handle more energy. The theta coil is reconfigured as a two - turn coil (160 nH) to facilitate the operation of a crowbar. The two-turn coil achieves a maximum current of 300 kA (= 1.2 T) at 20 kV of the main capacitor bank voltage and the operation of the crowbar allows for a monotonically decreasing current. With the 2-turn theta coil, a maximum plasma energy of ~ 0.08 MJ/m2 is achieved with 6 kV at the plasma gun and 20 kV at the theta pinch. Plasma velocities of 34 - 74 km/s are observed at the first few peaks of theta pinch current. A problem of plasma transport with short delay times is observed. Finally, the dissertation concludes with a few ways to further improve the device and increase the plasma heat flux. A change in the system design as well as a compact toroid generation are proposed and preliminary results are presented. The dissertation also suggests hardware upgrades which include an increase in the energy at the plasma gun / the theta pinch capacitor banks. At the same time, additional diagnostics will allow to further investigate the effect of pinching on the plasma from the plasma gun as well as determine the overall effect of the guiding magnetic field. (Abstract shortened by UMI.).

Low power interface IC's for electrostatic energy harvesting applications

NASA Astrophysics Data System (ADS)

Kempitiya, Asantha

The application of wireless distributed micro-sensor systems ranges from equipment diagnostic and control to real time structural and biomedical monitoring. A major obstacle in developing autonomous micro-sensor networks is the need for local electric power supply, since using a battery is often not a viable solution. This void has sparked significant interest in micro-scale power generators based on electrostatic, piezoelectric and electromagnetic energy conversion that can scavenge ambient energy from the environment. In comparison to existing energy harvesting techniques, electrostatic-based power generation is attractive as it can be integrated using mainstream silicon technologies while providing higher power densities through miniaturization. However the power output of reported electrostatic micro-generators to date does not meet the communication and computation requirements of wireless sensor nodes. The objective of this thesis is to investigate novel CMOS-based energy harvesting circuit (EHC) architectures to increase the level of harvested mechanical energy in electrostatic converters. The electronic circuits that facilitate mechanical to electrical energy conversion employing variable capacitors can either have synchronous or asynchronous architectures. The later does not require synchronization of electrical events with mechanical motion, which eliminates difficulties in gate clocking and the power consumption associated with complex control circuitry. However, the implementation of the EHC with the converter can be detrimental to system performance when done without concurrent optimization of both elements, an aspect mainly overlooked in the literature. System level analysis is performed to show that there is an optimum value for either the storage capacitor or cycle number for maximum scavenging of ambient energy. The analysis also shows that maximum power is extracted when the system approaches synchronous operation. However, there is a region of interest where the storage capacitor can be optimized to produce almost 70% of the ideal power taken as the power harvested with synchronous converters when neglecting the power consumption associated with synchronizing control circuitry. Theoretical predictions are confirmed by measurements on an asynchronous EHC implemented with a macro-scale electrostatic converter prototype. Based on the preceding analysis, the design of a novel ultra low power electrostatic integrated energy harvesting circuit is proposed for efficient harvesting of mechanical energy. The fundamental challenges of designing reliable low power sensing circuits for charge constrained electrostatic energy harvesters with capacity to self power its controller and driver stages are addressed. Experimental results are presented for a controller design implemented in AMI 0.7muM high voltage CMOS process using a macro-scale electrostatic converter prototype. The EHC produces 1.126muW for a power investment of 417nW with combined conduction and controller losses of 450nW which is a 20-30% improvement compared to prior art on electrostatic EHCs operating under charge constrain. Inherently dual plate variable capacitors harvest energy only during half of the mechanical cycle with the other half unutilized for energy conversion. To harvest mechanical energy over the complete mechanical vibration cycle, a low power energy harvesting circuit (EHC) that performs charge constrained synchronous energy conversion on a tri-plate variable capacitor for maximizing energy conversion is proposed. The tri-plate macro electrostatic generator with capacitor variation of 405pF to 1.15nF and 405pF to 1.07nF on two complementary adjacent capacitors is fabricated and used in the characterization of the designed EHC. The integrated circuit fabricated in AMI 0.7muM high voltage CMOS process, produces a total output power of 497nW to a 10muF reservoir capacitor from a 98Hz vibration signal. In summary, the thesis lays out the theoretical and experimental foundation for overcoming the main challenges associated with the design of charge constrained synchronous EHC's, making electrostatic converters a possible candidate for powering emerging communication transceivers and portable electronics.